Drought legacies in mixed Mediterranean forests: Analysing the effects of structural overshoot, functional traits and site factors

Previous favorable climate conditions stimulate tree growth making some forests more vulnerable to hotter droughts. This so-called structural overshoot may contribute to forest dieback, but there is little evidence on its relative importance depending on site conditions and tree species because of limited field data. Here, we analyzed remote sensing (NDVI) and tree-ring width data to evaluate the impacts of the 2017 drought on canopy cover and growth in mixed Mediterranean forests (Fraxinus ornus, Quercus pubescens, Acer monspessulanum, Pinus pinaster) located in southern Italy. Legacy effects were assessed by calculating differences between observed and predicted basal area increment (BAI). Overall, the growth response of the study stands to the 2017 drought was contingent on site conditions and species characteristics. Most sites presented BAI and canopy cover reductions during the drought. Growth decline was followed by a quick recovery and positive legacy effects, particularly in the case of F. ornus. However, we found negative drought legacies in some species (e.g., Q. pubescens, A. monspessulanum) and sites. In those sites showing negative legacies, high growth rates prior to drought in response to previous wet winter-spring conditions may have predisposed trees to drought damage. Vice versa, the positive drought legacy found in some F. ornus site was linked to post-drought growth release due to Q. pubescens dieback and mortality. Therefore, we found evidences of structural drought overshoot, but it was restricted to specific sites and species. Our findings highlight the importance of considering site settings such as stand composition, pre-drought conditions and different tree species when studying structural overshoot. Droughts contribute to modify the composition and dynamics in mixed forests.

Revealing legacy effects of extreme droughts on tree growth of oaks across the Northern Hemisphere

Forests are undergoing increasing risks of drought-induced tree mortality. Species replacement patterns following mortality may have a significant impact on the global carbon cycle. Among major hardwoods, deciduous oaks (Quercus spp.) are increasingly reported as replacing dying conifers across the Northern Hemisphere. Yet, our knowledge on the growth responses of these oaks to drought is incomplete, especially regarding post-drought legacy effects. The objectives of this study were to determine the occurrence, duration, and magnitude of legacy effects of extreme droughts and how that vary across species, sites, and drought characteristics. The legacy effects were quantified by the deviation of observed from expected radial growth indices in the period 1940-2016. We used stand-level chronologies from 458 sites and 21 oak species primarily from Europe, north-eastern America, and eastern Asia. We found that legacy effects of droughts could last from 1 to 5 years after the drought and were more prolonged in dry sites. Negative legacy effects (i.e., lower growth than expected) were more prevalent after repetitive droughts in dry sites. The effect of repetitive drought was stronger in Mediterranean oaks especially in Quercus faginea. Species-specific analyses revealed that Q. petraea and Q. macrocarpa from dry sites were more negatively affected by the droughts while growth of several oak species from mesic sites increased during post-drought years. Sites showing positive correlations to winter temperature showed little to no growth depression after drought, whereas sites with a positive correlation to previous summer water balance showed decreased growth. This may indicate that although winter warming favors tree growth during droughts, previous-year summer precipitation may predispose oak trees to current-year extreme droughts. Our results revealed a massive role of repetitive droughts in determining legacy effects and highlighted how growth sensitivity to climate, drought seasonality and species-specific traits drive the legacy effects in deciduous oak species.

Growth of tree (Pinus sylvestris) and shrub (Amelanchier ovalis) species is constrained by drought with higher shrub sensitivity in dry sites

We lack understanding of how variable is radial growth of coexisting tree and shrub species, and how growth is constrained by drought depending on site aridity. Here, we compared the radial growth of two widespread and coexisting species, a winter deciduous shrub (Amelanchier ovalis Medik.) and an evergreen conifer tree (Pinus sylvestris L.). We sampled four sites in Northeastern Spain subjected to different aridity levels and used dendrochronological methods to quantify growth patterns and responses to climate variables. The growth of the two species varied between regions, being lower in the driest sites. The first-order autocorrelation (growth persistence) was higher in more mesic sites but without clear differences between species. Tree and shrub growth negatively responded to elevated summer temperatures and positively to spring-summer precipitation and wet conditions. However, negative growth responses of the shrub to drought were only observed in the two driest sites in contrast to widespread responses of the tree. Abrupt growth reductions were common in the drier sites, but resilience indices show that the two species rapidly recovered pre-drought growth levels. The lower growth synchrony of the shrub as compared to the tree can be due to the multistemmed architecture, fast growth and low stature of the shrub. Besides, the high dependency of the shrub growth on summer rainfall can explain why drought limitations were only apparent in the two driest sites. In any case, results point out to the dendrochronological potential of shrubs, which is particularly relevant giving its ability to inhabit woodlands and treeless regions under harsh climatic conditions. Nevertheless, further research is required to elucidate the capacity of shrub species to tolerate drought, as well as to understand how shrubs thrive in water- and cold-limited environments.

Climatic drivers of cork growth depend on site aridity

Cork is one of the main non-timber forest products in the world. Most of its production is concentrated in the Iberian Peninsula, a climate change hotspot. Climate warming may lead to increased aridification and reduce cork production in that region. However, we still lack assessments of climate-cork relationships across ample geographical and climatic gradients explicitly considering site aridity. We quantified cork growth by measuring cork ring width and related it to climate variables and a drought index using dendrochronology. Four cork oak (Quercus suber) forests located from north eastern Spain to south western Morocco (31.5-41.5° N) and subjected to different aridity levels were sampled. Warm conditions in spring to early summer, when cork is formed, reduced cork width, whereas high precipitation in winter and spring enhanced it. The response of cork to increased water availability in summer peaked (r = 0.89, p = 0.00002) in the most arid and continental site considering 14-month long droughts. A severe drought caused a disproportionate loss of cork production in this site, where for every five-fold decrease in the drought index, the cork-width index declined by a factor of thirteen. Therefore, site aridity determines the responses of cork growth to the soil water availability resulting from accumulated precipitation during winter and spring previous to cork growth and until summer. In general, this cumulative water balance, which is very dependent on temperature and evapotranspiration rate, is critical for cork production, especially in continental, dry sites. The precipitation during the hydrological year can be used as a proxy of cork production in similar sites. Assessments of climate-cork relationships in the western Mediterranean basin could be used as analogues to forecast the impacts of aridification on future cork production.

Historical disconnection from floodplain alters riparian forest composition, tree growth and deadwood amount

Riparian forests are among the most dynamic but threatened terrestrial ecosystems. Their dynamism and conservation depend on historical changes in river geomorphology, which can be evaluated through changes in channel sinuosity. However, we lack long-term assessments on sinuosity and how they impact riparian forest composition, tree growth and deadwood amount. To fill this research gap, we reconstructed river sinuosity in 14 sites across the middle Ebro basin, north-eastern Spain, using historical aerial photographs taken in 1927, 1956, 1998-2003 and 2014-2015. Relationships between sinuosity, stand composition and deadwood amount and decay degree were calculated. We also reconstructed radial growth of the major tree species (Populus alba, Populus nigra, Fraxinus angustifolia, Salix alba and Ulmus minor) in two sites to evaluate how coupled it was with changes in river flow after dam building. From 1927 to 2015, sinuosity decreased passing from 1.39 to 1.20. The river dynamics were altered in the 1950s and 1960s after dam and dyke building. Sites with high sinuosity values in 1956 corresponded to mature stands with large P. nigra individuals. Sinuosity was negatively related to F. angustifolia (rs = -0.83, p < 0.001) and P. alba (rs = -0.64, p = 0.02) abundance, whereas sites dominated by P. alba and U. minor presented abundant decayed deadwood. A loss of sinuosity and a contraction of the riverbank gradient increased disconnection of active channel from floodplain, with a mixing of more (e.g., P. nigra) and less phreatophytic species (e.g., U. minor). River flow diversion reduced growth and increased the tree-to-tree P. alba growth coherence. Hydrological droughts contributed to growth decline and dieback of U. minor, which is sensitive to spring river flow. Conservation and restoration of riparian forests must consider historical changes in river geomorphology related to human activities.

Single-photon detection using high-temperature superconductors

The detection of individual quanta of light is important for quantum communication, fluorescence lifetime imaging, remote sensing and more. Due to their high detection efficiency, exceptional signal-to-noise ratio and fast recovery times, superconducting-nanowire single-photon detectors (SNSPDs) have become a critical component in these applications. However, the operation of conventional SNSPDs requires costly cryocoolers. Here we report the fabrication of two types of high-temperature superconducting nanowires. We observe linear scaling of the photon count rate on the radiation power at the telecommunications wavelength of 1.5 μm and thereby reveal single-photon operation. SNSPDs made from thin flakes of Bi₂Sr₂CaCu₂O_8+δ exhibit a single-photon response up to 25 K, and for SNSPDs from La_1.55Sr_0.45CuO₄/La₂CuO₄ bilayer films, this response is observed up to 8 K. While the underlying detection mechanism is not fully understood yet, our work expands the family of materials for SNSPD technology beyond the liquid helium temperature limit and suggests that even higher operation temperatures may be reached using other high-temperature superconductors.

Weak genetic differentiation but strong climate-induced selective pressure toward the rear edge of mountain pine in north-eastern Spain

Local differentiation at distribution limits may influence species' adaptive capacity to environmental changes. However, drivers, such gene flow and local selection, are still poorly understood. We focus on the role played by range limits in mountain forests to test the hypothesis that relict tree populations are subjected to genetic differentiation and local adaptation. Two alpine treelines of mountain pine (Pinus uncinata Ram. ex DC) were investigated in the Spanish Pyrenees. Further, an isolated relict population forming the species' southernmost distribution limit in north-eastern Spain was also investigated. Using genotyping by sequencing, a genetic matrix conformed by single nucleotide polymorphisms (SNPs) was obtained. This matrix was used to perform genotype-environment and genotype-phenotype associations, as well as to model risk of non-adaptedness. Increasing climate seasonality appears as an essential element in the interpretation of SNPs subjected to selective pressures. Genetic differentiations were overall weak. The differences in leaf mass area and radial growth rate, as well as the identification of several SNPs subjected to selective pressures, exceeded neutral predictions of differentiation among populations. Despite genetic drift might prevail in the isolated population, the Fst values (0.060 and 0.066) showed a moderate genetic drift and Nm values (3.939 and 3.555) indicate the presence of gene flow between the relict population and both treelines. Nonetheless, the SNPs subjected to selection pressures provide evidences of possible selection in treeline ecotones. Persistence in range boundaries seems to involve several selective pressures in species' traits, which were significantly related to enhanced drought seasonality at the limit of P. uncinata distribution range. We conclude that gene flow is unlikely to constrain adaptation in the P. uncinata rear edge, although this species shows vulnerability to future climate change scenarios involving warmer and drier conditions.

Tree-ring and remote sensing analyses uncover the role played by elevation on European beech sensitivity to late spring frost

Extreme climate events such as late spring frosts (LSFs) negatively affect productivity and tree growth in temperate beech forests. However, detailed information on how these forests recover after such events are still missing. We investigated how LSFs affected forest cover and radial growth in European beech (Fagus sylvatica L.) populations located at different elevations at four sites in the Italian Apennines, where LSFs have been recorded. We combined tree-ring and remote-sensing data to analyse the sensitivity and recovery capacity of beech populations to LSFs. Using daily temperature records, we reconstructed LSF events and assessed legacy effects on growth. We also evaluated the role played by elevation and stand structure as modulators of LSFs impacts. Finally, using satellite images we computed Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI) and LAI (Leaf Area Index) to evaluate the post-LSF canopy recovery. The growth reduction in LSF-affected trees ranged from 36 % to 84 %. We detected a negative impact of LSF on growth only during the LSF year, with growth recovery occurring within 1-2 years after the event. LSF-affected stands featured low vegetation indices until late June, i.e. on average 75 days after the frost events. We did not find a clear relationship between beech forest elevation and occurrence of LSFs defoliations. Our results indicate a high recovery capacity of common beech and no legacy effects of LSFs.

The role of nutritional impairment in carbon-water balance of silver fir drought-induced dieback

Rear-edge populations at the xeric distribution limit of tree species are particularly vulnerable to forest dieback triggered by drought. This is the case of silver fir (Abies alba) forests located in Southwestern Europe. While silver fir drought-induced dieback patterns have been previously explored, information on the role played by nutritional impairment is lacking despite its potential interactions with tree carbon-water balances. We performed a comparative analysis of radial growth, intrinsic water-use efficiency (iWUE), oxygen isotopes (δ¹⁸ O) and nutrient concentrations in leaves of declining (DD) and non-declining (ND) trees in silver fir in four forests in the Spanish Pyrenees. We also evaluated the relationships among dieback predisposition, intraspecific trait variation (wood density and leaf traits) and rhizosphere soil physical-chemical properties. The onset of growth decline in DD trees occurred more than two decades ago, and they subsequently showed low growth resilience against droughts. The DD trees presented consistently lower foliar concentrations of nutrients such as P, K, Cu and Ni than ND trees. The strong effects of foliar nutrient status on growth resilience indices support the key role played by mineral nutrition in tree functioning and growth before, during and after drought. In contrast, variability in wood density and leaf morphological traits, as well as soil properties, showed weak relationships with tree nutritional status and drought performance. At the low elevation, warmer sites, DD trees showed stronger climate-growth relationships and lower δ¹⁸ O than ND trees. The uncoupling between iWUE and δ¹⁸ O, together with the positive correlations between P and K leaf concentrations and δ¹⁸ O, point to deeper soil/bedrock water sources and vertical decoupling between nutrient and water uptake in DD trees. This study provides novel insights into the mechanisms driving silver fir dieback and highlights the need to incorporate tree nutrition into forest dieback studies.

P110 ACCIDENTAL FINDING OF COR TRIATRIUM SINISTER IN AN ADULT: DIAGNOSIS MANAGMENT

A 45–year old woman presented at the emergency department for palpitations and fever. The EKG, thoracic x–ray and troponins were normal, only a neutrophil leucocytosis was found. The echocardiography showed a normal bi–ventricular and valvular function and a mobile, linear, mass in the left atrium. In order to exclude an infective vegetation the patient underwent to a 2D and 3D transesophageal echocardiography (Figure 1 and 2) which showed a left ventricle concentric remodelling (iLVmass 62 g/m2; RWT 0.45), preserved left and right ventricle function (LVEF according to Simpson 70%; FAC 50%) and valves function; inter–atrial septum defects were excluded, too. The mass was described as a mobile membrane in the left atrium at 2.11 cm from the mitral valve anular plane, which divided the atrium into two separate chambers with a large fenestration without trans–mitralic flow obstruction, supporting a cor triatrium sinister. We excluded endocarditis (the blood cultures were negative, too) and supra–valvular mitral ring (since the left appendage position in the antero–inferior side of the left atrium). The cardiac MRI showed (Figure 3) (SSFP–FIESTA, IR–GRE T1, STIR T2) confirmed the finding of a left atrium divided in two chamber by a iso–intense membraine from the coumadin ridge between the left upper pulmonary vein and the left appendage to the inter–atrial septum fossa ovalis, incomplete in the infero–lateral part. Venous drenaige and other congenital abnormalities were excluded. Miocarditis was excluded since no fibrosis in IR–GRE T1 and no edema in Triple T2 sequences. Since the non–obstructive cor triatrium sinister, grading IA according the Lucas classification, was confirmed, no surgical treatment was proposed and the patient was discharged without complications.

Declines in canopy greenness and tree growth are caused by combined climate extremes during drought-induced dieback

Several dieback episodes triggered by droughts are revealing the high vulnerability of Mediterranean forests, manifested as declines in growth, increased defoliation, and rising mortality rates. Understanding forest responses to such climate extreme events is of high priority for predicting their future vegetation dynamics. We examined how remotely sensed measures of vegetation activity (NDVI, Normalized Difference Vegetation Index) and radial growth (BAI, basal area increment) responded to climate extreme events. We considered tree (Pinus sylvestris, Quercus pubescens, Quercus frainetto) and shrub (Juniperus phoenicea) populations from Italy and Spain showing recent dieback phenomena. Two components of drought, namely elevated atmospheric demand (VPD, vapor pressure deficit) and low soil moisture were analyzed in nearby stands showing or not showing dieback symptoms. Dieback stands exhibited lower NDVI values than non-dieback stands. NDVI and BAI were positively related in all sites except for the dieback stand of Q. frainetto that was negatively related. Such NDVI-BAI linkages were related to specific time windows, which could be useful for identifying when climatic conditions have the greatest influence on vegetation. Growth decline occurred in response to increasing VPD, but responses differed among species. J. phoenicea was the most negatively impacted by higher VPD, whereas oaks responded to soil moisture. A high VPD was related to stronger growth reduction in dieback P. sylvestris trees regardless of soil moisture changes. We highlighted that coupling between proxies of forest productivity (NDVI, BAI) allows better understanding and forecasting of drought-induced dieback phenomena in forests and shrublands. Scaling up from tree to stand levels might be feasible when using the maximum growing season NDVI, which can be applied for retrospective modeling of the impact of drought stress on forest productivity and tree growth.

Mediterranean old-growth forests exhibit resistance to climate warming

Old-growth mountain forests represent an ideal setting for studying long-term impacts of climate change. We studied the few remnants of old-growth forests located within the Pollino massif (southern Italy) to evaluate how the growth of conspecific young and old trees responded to climate change. We investigated two conifer species (Abies alba and Pinus leucodermis) and two hardwood species (Fagus sylvatica and Quercus cerris). We sampled one stand per species along an altitudinal gradient, ranging from a drought-limited low-elevation hardwood forest to a cold-limited subalpine pine forest. We used a dendrochronological approach to characterize the long-term growth dynamics of old (age > 120 years) versus young (age < 120 years) trees. Younger trees grew faster than their older conspecifics during their juvenile stage, regardless of species. Linear mixed effect models were used to quantify recent growth trends (1950-2015) and responses to climate for old and young trees. Climate sensitivity, expressed as radial growth responses to climate during the last three decades, partially differed between species because high spring temperatures enhanced conifer growth, whereas F. sylvatica growth was negatively affected by warmer spring conditions. Furthermore, tree growth was negatively impacted by summer drought in all species. Climate sensitivity differed between young and old trees, with younger trees tending to be more sensitive in P. leucodermis and A. alba, whereas older F. sylvatica trees were more sensitive. In low-elevation Q. cerris stands, limitation of growth due to drought was not related to tree age, suggesting symmetric water competition. We found evidence for a fast-growth trend in young individuals compared with that in their older conspecifics. Notably, old trees tended to have relatively stable growth rates, showing remarkable resistance to climate warming. These responses to climate change should be recognized when forecasting the future dynamics of old-growth forests for their sustainable management.

Inter and intra-annual links between climate, tree growth and NDVI: improving the resolution of drought proxies in conifer forests

The inter- and intra-annual variability in radial growth reflects responses to climatic variability and water shortage, especially in areas subjected to seasonal drought. However, it is unknown how this variability is related to forest productivity, which can be assessed by measuring changes in canopy greenness and cover through remote sensing products as the Normalized Difference Vegetation Index (NDVI). We combine xylogenesis with measurements of inter-annual changes in seasonal wood production (earlywood width, adjusted latewood width) and NDVI to improve the understanding of climate and drought impacts on growth and forest productivity in a Pinus teocote stand located in northern Mexico. Cambial dynamics accelerated in March and a high production of radially enlarging and thickening tracheids were observed from April to October and from June to October, respectively. Tracheid maturation was very active in October when latewood production peaked. Wet conditions in winter-spring and summer-autumn enhanced earlywood and latewood production, respectively. Earlywood and latewood were constrained by long (4-10 months) and short (2-3 months) droughts, respectively. The earlywood production depended on April soil moisture, which agrees with the peak of radially enlarging tracheid production found during that month. Aligning drought proxies at inter- and intra-annual scales by using growth and productivity measures improves our understanding of conifer forest responses to water shortage.

Differences in temperature sensitivity and drought recovery between natural stands and plantations of conifers are species-specific

Forests are being impacted by climate and land-use changes which have altered their productivity and growth. Understanding how tree growth responds to climate in natural and planted stands may provide valuable information to prepare management in sight of climate change. Plantations are expected to show higher sensitivity to climate and lower post-drought resilience than natural stands, due to their lower compositional and structural diversity. We reconstructed and compared the radial growth of six conifers with contrasting ecological and climatic niches (Abies pinsapo, Cedrus atlantica, Pinus sylvestris, Pinus nigra, Pinus pinea, Pinus pinaster) in natural and planted stands subjected to seasonal drought in 40 sites. We quantified the relationships between individual growth variability and climate variables (temperature, precipitation and the SPEI drought index), as well as post-drought resilience. Elevated precipitation during the previous autumn-winter and current spring to early summer enhanced growth in both natural and planted stands of all species. Temperature effects on growth were less consistent: only plantations of A. pinsapo, C. atlantica, P. nigra, P. pinea, P. sylvetris and a natural stand of P. nigra showed negative impacts of summer temperature on growth. Drought reduced growth of all species in both plantations and natural stands, with variations in the temporal scale of the response. Drought constrained growth more severely in natural stands than in plantations of C. atlantica, P. pinaster and P. nigra, whereas the inverse pattern was found for A. pinsapo. Resilience to drought varied between species: natural stands of A. pinsapo, C. atlantica and P. pinaster recovered faster than plantations, while P. pinea plantations recovered faster than natural stands. Overall, plantations did not consistently show a higher sensitivity to climate and a lower capacity to recover after drought. Therefore, plantations are potential tools for mitigating climate warming.

Modeling Climate Impacts on Tree Growth to Assess Tree Vulnerability to Drought During Forest Dieback

Forest dieback because of drought is a global phenomenon threatening particular tree populations. Particularly vulnerable stands are usually located in climatically stressing locations such as xeric sites subjected to seasonal drought. These tree populations show a pronounced loss of vitality, growth decline, and high mortality in response to extreme climate events such as heat waves and droughts. However, dieback events do not uniformly affect stands, with some trees showing higher symptoms of drought vulnerability than other neighboring conspecifics. In this study, we investigated if trees showing different vulnerabilities to dieback showed lower growth rates (Grs) and higher sensitivities to the climate in the past using dendroecology and the Vaganov-Shashkin (VS) process-based growth model. We studied two Pinus pinaster stands with contrasting Grs showing recent dieback in the Iberian System, north-eastern Spain. We compared coexisting declining (D) and non-declining (ND) trees with crown defoliation values above and below the 50% threshold, respectively. The mean growth rate was lower in D than in ND trees in the two stands. The two vigor classes showed a growth divergence prior to the dieback onset and different responsiveness to climate. The ND trees were more responsive to changes in spring water balance and soil moisture than D trees, indicating a loss of growth responsiveness to the climate in stressed trees. Such an interaction between water availability and vigor was reflected by the VS-model simulations, which provided evidence for the observation that growth was mainly limited by low soil moisture in both sites. Such an interaction between water availability and vigor was reflected by the VS-model simulations, which provided evidence for the observation that growth was mainly limited by low soil moisture in both sites. The presented comparisons indicated different stand vulnerabilities to drought contingent on-site conditions. Further research should investigate the role played by environmental conditions and individual features such as access to soil water or hydraulic traits and implement them in process-based growth models to better forecast dieback.

Single-photon detection in the mid-infrared up to 10 μm wavelength using tungsten silicide superconducting nanowire detectors

We developed superconducting nanowire single-photon detectors based on tungsten silicide, which show saturated internal detection efficiency up to a wavelength of 10 μm. These detectors are promising for applications in the mid-infrared requiring sub-nanosecond timing, ultra-high gain stability, low dark counts, and high efficiency, such as chemical sensing, LIDAR, dark matter searches, and exoplanet spectroscopy.

Superconducting Nanowire Spiking Element for Neural Networks

As the limits of traditional von Neumann computing come into view, the brain's ability to communicate vast quantities of information using low-power spikes has become an increasing source of inspiration for alternative architectures. Key to the success of these largescale neural networks is a power-efficient spiking element that is scalable and easily interfaced with traditional control electronics. In this work, we present a spiking element fabricated from superconducting nanowires that has pulse energies on the order of ∼10 aJ. We demonstrate that the device reproduces essential characteristics of biological neurons, such as a refractory period and a firing threshold. Through simulations using experimentally measured device parameters, we show how nanowire-based networks may be used for inference in image recognition and that the probabilistic nature of nanowire switching may be exploited for modeling biological processes and for applications that rely on stochasticity.

Long-term thinning effects on tree growth, drought response and water use efficiency at two Aleppo pine plantations in Spain

In Mediterranean areas where drought-induced forest dieback and tree mortality have been widely reported, it is still under debate how the likely risks of climate change will affect tree growth and consequently forest productivity. Increasing tree mortality has been associated not only to increased drought, but also to a lack of management in many dense pine forests and plantations, where warming may intensify tree-to-tree competition for soil water. This emphasizes the need of using silviculture to adapt dense stands of Mediterranean pine reforestations to warmer and drier conditions. Here we combined dendrochronology and C and O isotope analyses of wood in two Aleppo pine (Pinus halepensis) plantations, growing under semiarid conditions and experimentally thinned at high and moderate intensities along with control. The main aim was to understand the responses of radial growth and water use efficiency (WUEi) to different thinning intensities, and to analyze the effectiveness of thinning to enhance post-drought growth resilience. Thinning had a positive effect on growth, produced an increase of δ¹⁸O, reduced growth sensitivity to drought and decreased WUEi, suggesting a reduction of drought stress. These results were consistent across sites, and were significant even 20 years after the intervention took place. Considering the climate effects on growth through the SPEI drought index to calculate resistance and recovery indices, an increase of resistance after thinning was observed. We conclude that high thinning intensity (50% of basal area removed) is a useful silviculture intervention on Mediterranean Aleppo pine plantations that enhances their growth, and makes them less dependent on harsh climatic conditions, improving their resilience against drought and consequently making them better adapted to more unfavourable conditions.

Variation in the access to deep soil water pools explains tree-to-tree differences in drought-triggered dieback of Mediterranean oaks

Individual differences in the access to deep soil water pools may explain the differential damage among coexisting, conspecific trees as a consequence of drought-induced dieback. We addressed this issue by comparing the responses to a severe drought of three Mediterranean oak species with different drought tolerance, Quercus pubescens L. and Quercus frainetto Ten., mainly thriving at xeric and mesic sites, respectively, and Quercus cerris L., which dominates at intermediate sites. For each species, we compared coexisting declining (D) and non-declining (ND) trees. The stable isotope composition (δ2H, δ18O) of xylem and soil water was used to infer a differential use of soil water sources. We also measured tree size and radial growth to quantify the long-term divergence of wood production between D and ND trees and non-structural carbohydrates (NSCs) in sapwood to evaluate if D trees presented lower NSC values. The ND trees had access to deeper soil water than D trees except in Q. frainetto, as indicated by significantly more depleted xylem water values. However, a strong δ2H offset between soil and xylem water isotopes observed in peak summer could suggest that both tree types were not physiologically active under extreme drought conditions. Alternative processes causing deuterium fractionation, however, could not be ruled out. Tree height and recent (last 15-25 years) growth rates in all species studied were lower in D than in ND trees by 22 and 44%, respectively. Lastly, there was not a consistent pattern of NSC sapwood concentration; in Q. pubescens, it was higher in ND trees while in Q. frainetto, the D trees were the ones exhibiting the higher NSC concentration. We conclude that the vulnerability to drought among conspecific Mediterranean oaks depends on the differential access to deep soil water pools, which may be related to differences in rooting depth, tree size and growth rate.

The Response of Osteoblasts and Bone to Sinusoidal Electromagnetic Fields: Insights from the Literature

Electromagnetic fields (EMFs) have been proposed as a tool to ameliorate bone formation and healing. Despite their promising results, however, they have failed to enter routine clinical protocols to treat bone conditions where higher bone mass has to be achieved. This is no doubt also due to a fundamental lack of knowledge and understanding on their effects and the optimal settings for attaining the desired therapeutic effects. This review analysed the available in vitro and in vivo studies that assessed the effects of sinusoidal EMFs (SEMFs) on bone and bone cells, comparing the results and investigating possible mechanisms of action by which SEMFs interact with tissues and cells. The effects of SEMFs on bone have not been as thoroughly investigated as pulsed EMFs; however, abundant evidence shows that SEMFs affect the proliferation and differentiation of osteoblastic cells, acting on multiple cellular mechanisms. SEMFs have also proven to increase bone mass in rodents under normal conditions and in osteoporotic animals.

Bridging the Gap Between Nanowires and Josephson Junctions: A Superconducting Device Based on Controlled Fluxon Transfer

The basis for superconducting electronics can broadly be divided between two technologies: the Josephson junction and the superconducting nanowire. While the Josephson junction (JJ) remains the dominant technology due to its high speed and low power dissipation, recently proposed nanowire devices offer improvements such as gain, high fanout, and compatibility with CMOS circuits. Despite these benefits, nanowire-based electronics have largely been limited to binary operations, with devices switching between the superconducting state and a high-impedance resistive state dominated by uncontrolled hotspot dynamics. Unlike the JJ, they cannot increment an output through successive switching and their operation speeds are limited by their slow thermal-reset times. Thus, there is a need for an intermediate device with the interfacing capabilities of a nanowire but a faster, moderated response allowing for modulation of the output. We present a nanowire device based on controlled fluxon transport. We show that the device is capable of responding proportionally to the strength of its input, unlike other nanowire technologies. The device can be operated to produce a multilevel output with distinguishable states, the number of which can be tuned by circuit parameters. Agreement between experimental results and electrothermal circuit simulations demonstrates that the device is classical and may be readily engineered for applications including use as a multilevel memory.

Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy

Forest decline induced by climate change is a global phenomenon that affects many tree species, mainly in drought-prone areas as the Mediterranean region. In southern Italy, several oak species have shown decline symptoms and elevated mortality since the 2000s due to drought stress. However, it remains to be answered whether decline occurred alone or whether a pathogen was also involved. To this aim, we compared two coexisting oak species in a forest located in southern Italy which are assumed to be less (Quercus cerris) and more tolerant to drought (Quercus pubescens). We sampled fifteen couples of neighboring declining (D) and non-declining (ND) trees of both species. Wood cores were taken from all trees to perform dendrochronological analyses to detect the decline onset and link it to potential climatic drivers. Carbon isotope ratios (d13C) were analyzed in wood of the two vigor classes to compare their water-use efficiency. Phytophthora presence was also assessed in soil samples from ten D-ND couples of trees per species. The oak species most affected by drought-induced decline in terms of leaf shedding and mortality was Q. cerris, i.e., the least tolerant to drought. In both species, the D trees showed a reduced growth rate compared with ND trees from 2000 onward when drought and warming intensified. Q. pubescens showed higher growth sensitivity to precipitation, temperature and drought than Q. cerris. This sensitivity to climate was magnified in D trees whose growth decreased in response to warm and dry conditions during the prior winter and the late summer. The Q. pubescens D trees were more efficient in their water use than ND trees before the growth divergence between D and ND trees amplified. In the studied area, Phytophthora quercina was isolated from 40% of the sampled trees, and tended to be more frequent amongst ND than amongst D trees. Our data suggests that droughts and warm summer conditions triggered oak decline. The high prevalence of P. quercina in the studied area warrants further study as a potential predisposing factor.

A multi-proxy assessment of dieback causes in a Mediterranean oak species

Drought stress causes forest dieback that is often explained by two interrelated mechanisms, namely hydraulic failure and carbon starvation. However, it is still unclear which functional and structural alterations, related to these mechanisms, predispose to dieback. Here we apply a multi-proxy approach for the characterization of tree structure (radial growth, wood anatomy) and functioning (δ13C, δ18O and non-structural carbohydrates (NSCs)) in tree rings before and after drought-induced dieback. We aim to discriminate which is the main mechanism and to assess which variables can act as early-warning proxies of drought-triggered damage. The study was tailored in southern Italy in two forests (i.e., San Paolo (SP) and Oriolo (OR)) where declining and non-declining trees of a ring-porous tree species (Quercus frainetto Ten.) showing anisohydric behavior coexist. Both stands showed growth decline in response to warm and dry spring conditions, although the onset of dieback was shifted between them (2002 in SP and 2009 in OR). Declining trees displayed a sharp growth drop after this onset with reductions of 49% and 44% at SP and OR sites, respectively. Further, contrary to what we expected, declining trees showed a lower intrinsic water-use efficiency compared with non-declining trees after the dieback onset (with reductions of 9.7% and 5.6% at sites SP and OR, respectively), due to enhanced water loss through transpiration, as indicated by the lower δ18O values. This was more noticeable at the most drought-affected SP stand. Sapwood NSCs did not differ between declining and non-declining trees, indicating no carbon starvation in affected trees. Thus, the characterized structural and functional alterations partially support the hydraulic failure mechanism of dieback. Finally, we show that growth data are reliable early-warning proxies of drought-triggered dieback.

Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death

Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees.

Treatment of renal angiomyolipoma: surgery versus angioembolization

Renal angiomyolipoma (AML) is a benign mesenchymal tumour. AML often leads to haemorrhagic complications such as retroperitoneal haematoma. Treatment varies from case to case, ranging from minimally invasive approaches such as selective embolization of the renal artery to invasive wedge resection, partial nephrectomy or, in more severe cases, radical nephrectomy. Here we report a case of retroperitoneal haematoma secondary to AML, treated with conservative approach by super-selective embolization of the lower-pole segmental renal artery.

Breast-conserving surgery after neoadjuvant chemotherapy in patients with locally advanced cancer. Preliminary results

Neoadjuvant chemotherapy (NACT) in locally advanced breast tumors may allow an adequate control of the disease impossible with surgery alone. Moreover, NACT increases the chance of breast-conserving surgery. Between 2008 and 2012, we treated with NACT 83 patients with locally advanced breast cancer. We report the preliminary results evaluating the impact of NACT on the type of surgery.

Hamartoma of the breast in a young woman. Case report

Hamartoma is a benign tumor-like malformation characterized by a focal mixture of mature cells and tissues normally present in affected area. The hamartoma of the breast is rare. We report a case in an asymptomatic young woman coming to our attention for a left breast lesion detected by ultrasound screening.

Case report: Inflammatory myofibroblastic tumor of pancreatic origin in a patient with down syndrome: The role of diagnostic ultrasound

INTRODUCTION

Inflammatory myofibroblastic tumor (IMT) is a benign solid tumor of uncertain etiology.

MATERIALS AND METHODS

We report a case of a 4-year-old Down syndrome affected child, who had a pancreatic mass identified by ultrasonography (US) and confirmed by computed tomography (CT).

RESULTS

Monitoring of IMT was performed by serial US studies, and at follow-up after 4 years there was no relapse.

DISCUSSION

As radical removal of the lesion was not possible, the patient was successfully treated with nonsteroidal anti-inflammatory drugs (NSAIDs). It was decided to monitor the lesion by serial US in order to reduce the number of CT examinations and thereby avoid excessive exposure to ionizing radiation. It is widely reported in the literature that repeated CT scans are associated with increased exposure to radiation which may cause cancer, a fact which should not be overlooked in children.

[A "I would like to give him my life": results of a psychological support intervention to caregivers of patients undergoing neuromotor rehabilitation]

A large proportion of patients hospitalised for severe neuromotor disorders are supported during the in-hospital rehabilitation program by family members. To target interventions of psychological support for these caregivers it can be of help to identify the causes of caregiver burden or specific needs. Anxiety and depression are common in caregivers and constitute, together with emotional distress caused by loneliness and reduced social activities, an important part of the caregiving burden. This paper presents results emerging from a clinical intervention of psychological support offered to caregivers of neuromotor patients, mainly post-stroke, who were undergoing a course of in-hospital rehabilitation. A psychometric assessment was carried out on a sample of 50 caregivers, spouses or children, at the beginning and end of the in-hospital rehabilitation period. The following questionnaires were used: the Revised Anxiety and Depression Scale (RADS), measuring anxiety and depression, the Caregiver Need Assessment (CNA), assessing needs related to the assisted patient, and the Family Strain Questionnaire (FSQ) for a broader assessment of the problems faced by caregivers. The Functional Independence Measure (FIM) was completed by the medical doctor. A significant reduction was found, between the beginning and end of the rehabilitation period, in the needs related to patient care on the CNA (p < 0.001). Caregiver females, in contrast to males, showed an improvement in mood compared to the beginning of the rehabilitation period (p < 0.05). About half of the sample had, at the beginning, a marked clinical level of anxiety while 22% of caregivers had a marked clinical level of depression. Caregivers who received intense psychological support, i.e. at least one interview with the psychologist per week, showed, in contrast to those who received 3-4 interviews during the entire rehabilitation period, a decline in thoughts of death (p < 0.05) and, in cases where baseline anxiety was above the clinical cut-off, a reduced level of anxiety (p < 0.05). At the beginning of rehabilitation, there emerged: higher anxiety scores in caregivers who live with their patient (p < 0.05) compared to those living alone or with others; an increase in depression scores in inverse proportion to the patient's age (p = 0.01); higher scores of emotional stress in spouses (p < 0.05) compared to children and in caregivers of patients with left hemisphere deficits (p < 0.05); a greater need for knowledge about the disease (p < 0.001) and more thoughts of death (p < 0.05) in caregivers of female patients. These characteristics may be considered "alarm signals" that should alert hospital medical staff to the need to seek psychological help for the caregiver. At the end of rehabilitation, a greater degree of psychological strain was observed in caregivers of patients with severe disability. High needs related to the assisted patient (p < 0.01), high scores of emotional stress (p < 0.05), problems of social involvement (p < 0.05) and thoughts of death about the patient (p < 0.05) were found in caregivers of patients who had persisting high motor disability or who were admitted for consequences of a left hemisphere lesion. High depression scores were also found in caregivers of patients with high residual cognitive disability (p < 0.05). This psychometric evaluation makes it possible to tailor the psychological support offered to the needs of each individual caregiver both during rehabilitation and in relation to eventual future developments. A multidisciplinary team approach to the caregiver can thus lead to a general reduction of caregiver strain.

Docetaxel and oxaliplatin in the second-line treatment of platinum-sensitive recurrent ovarian cancer: a phase II study

BACKGROUND

A prospective phase II study was conducted to evaluate the efficacy and toxicity of the combination docetaxel (Taxotere) (DTX) and oxaliplatin (OXA) in ovarian cancer patients recurring after a platinum-free interval (PFI) >12 months.

PATIENTS AND METHODS

DTX, 75 mg/m(2), was administered by 60 min i.v. infusion, followed by OXA, 100 mg/m(2), given by a 2 h i.v., on day 1 every 21 days.

RESULTS

From October 2003 to June 2006, 43 ovarian cancer patients were enrolled. Median PFI was 26 months. All patients were available for response evaluation: 17 complete responses and 12 partial responses were registered, for an overall response rate of 67.4%. The median response duration was 10 months. Stable disease was documented in 11 patients (median duration = 5.5 months). The median time to progression and overall survival were 14 and 28 months. A total of 259 courses were administered. Grade 3-4 leukopenia was documented in 32.5% of the patients, while no case of severe anemia and thrombocytopenia was observed. Grade 3-4 neurotoxicity and grade 2 alopecia were observed in 9.3% and 34.9% of cases, respectively.

CONCLUSION

DTX/OXA combination is an active regimen with a favorable toxicity profile, for treatment of recurrent platinum-sensitive ovarian cancer patients.

Phase II study on the combination carboplatin-celecoxib in heavily pre-treated recurrent ovarian carcinoma patients

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Background: Cyclooxygenase-2 (COX-2) has been shown to be involved in several steps of ovarian onset and progression and its overepression is associated with a poor chance of response to chemotherapy and poor prognosis in ovarian cancer. Celecoxib, an orally active selective COX-2 inhibitor, has been tested for its ability to potentiate the activity of carboplatin in treatment of heavily pretreated recurrent ovarian cancer patients. Methods: A phase II study was planned, considering the regimen active if at least 12 responses were observed among the 43 enrolled patients. Celecoxib (400 mg/die), and carboplatin (5 AUC) q28 were administered, until progression or unacceptable toxicity. Response was assessed by RECIST and also by Rustin criteria. Results: 34 pts (median age: 60 yrs, range 28–74) and an ECOG performance status (0/1/2) of (21/12/1), were enrolled. 58.8% of patients were platinum resistant (progressing during or < 6 months from primary treatment). Median number of previous chemotherapy regimens was 3 (range 2–6). Currently 27 patients are evaluable for response. The overall response rate (CR and PR) was 25.9% (2 CR, 5 PR) with stabilization of disease in 8 patients (29.6%). Four responses occurred in platinum sensitive and 3 in platinum resistant group Median time to response was 11 weeks (range 9–19) and median duration of response was 23 weeks (range 12–39). According to Rustin criteria 10 patients out of 25 (40%) were considered responsive to treatment (return of CA125 levels to normal level or >50% reduction). Overall, 143 cycles were administered with a median value of 3 cycles (range = 1–10). Moderate/severe toxicities were as follows: G3 anemia occurred in 2.3% cycles, G3 neutropenia in 4.6% cycles, G3 thrombocytopenia in 1.5% cycles, G3/4 gastrointestinal toxicity occurred in 4.6% cycles. Cutaneous diffuse erithema was observed in 2 patients, in both cases recovered with a short period of antihistaminic treatment; 2 cases of hypertension were documented, G2 hypersensitivity reactions during carboplatin infusion were observed in 4 cases. Conclusions: Celecoxib combined with carboplatin is well tolerated and has promising activity as salvage treatment in heavily pretreated recurrent ovarian cancer patients.

No significant financial relationships to disclose.

Black-white differences in health perceptions among the indigent

Two studies were conducted that assessed health perceptions and functional health status among an urban, low-income population in the southeastern region of the United States. The first study was conducted with 176 hospitalized indigent patients prior to discharge from a county hospital. Patients were administered the Short Form-36 (SF-36) health status questionnaire and two additional questions regarding perceptions of health. The second study was conducted in the same geographic region with a nonhospitalized, low-income population. The SF-36 was administered by telephone to 546 randomly selected interview respondents. The results demonstrated consistent differences between black and white respondents in referents for self-perceived health. It is suggested that health expectations and perceptions may be indicative of the cultural, contextual, and social-political factors that affect the lives of this urban, low income population. The validity of global single-item health indicators for use among low-income populations is questioned. Further research is needed to develop patient-based measures that accurately reflect the meanings and values of low-income patient groups.

Giant aneurysm of the calloso-marginal artery

A giant aneurysm of the right callosomarginal artery is reported in a 3-month-old child. This location is rare: including our case reported here, only three cases have been described. Clinicoradiological findings are presented and the surgical procedure is illustrated.

Neurological and behavioral sequelae following different approaches to craniopharyngioma. Long-term follow-up review and therapeutic guidelines

The criteria by which the operative approaches to craniopharyngioma are chosen are still controversial. The authors performed a retrospective analysis in 32 patients with craniopharyngioma who were surgically treated. Results of neurological and psychological tests administered during the follow-up period were correlated with the surgical approach. On the basis of these preliminary data and a maximum follow-up period of 10 years, the authors conclude that the subfrontal approach to the craniopharyngioma and partial removal of its solid part appears to be associated with a lower morbidity rate and minor frontal lobe disorders.

Neurological and behavioral sequelae in children operated on for brain abscess

In order to characterize neurological, intellectual and behavioral sequelae better after surgical treatment of brain abscess in childhood, 32 children were studied over a 10-year time span after treatment of a brain abscess. Depending on the clinical condition, surgical treatment consisted of simple aspiration through a burr hole or of total excision after craniotomy. There were only 3 postoperative deaths (9%). The scheduled time for long-term follow-up was 3 years after surgery. The patient assessment included information concerning the presence of seizures, accurate neurological examination, an EEG, and a battery of intellectual tests to evaluate the presence of behavioral-mental deficits. Late seizures developed in 7 of the 29 survivors. Five patients presented permanent hemiparesis after surgical treatment. It is noteworthy that the intellectual impairment observed was more severe in younger patients, while the behavioral disturbances were more marked in school-age children.

Medulloblastoma: a critical approach to the management on the basis of 12 years of experience

Medulloblastoma constituted 28% of brain neoplasms among children referred to the Santobono Children's Hospital of Naples from 1973 through October 1984. The authors summarize their experience with 68 cases of medulloblastoma, which were managed with a multimodal institutional protocol involving surgery, chemotherapy and radiation therapy. The evolution of modern management is discussed, and particular attention is directed to the factors affecting the prognosis.

Migration of distal catheter of the ventriculo-mitral shunt into the right atrium. Case report

A rare case of migration of a distal catheter from a ventriculo-atrial shunt into the right atrium is presented. The employed surgical procedure for the removal of the foreign body from the heart is briefly discussed.

Intracranial tumors in early infancy (under one year of age)

The diagnosis of intracranial neoplasm represents a difficult clinical problem in early infancy. The authors report their experience at Children's Hospital, Neurosurgical Department, of Naples, with intracranial tumors in children under one year of age.