Evaluation of particulate organic carbon from MODIS-Aqua in a marine-coastal water body

La Paz Bay (LPB) in Mexico is one of the largest marine-coastal bodies of water in the Gulf of California (GC) and is ecologically important for the feeding, reproduction, and refuge of marine species. Although particulate organic carbon (POC) is an important reservoir of oceanic carbon and an indicator of productivity in the euphotic zone, studies in this region are scarce. This study evaluates the performance of satellite-derived POC in LPB from January 2003 to December 2020. The metrics obtained for COP ( RMSE = 33.8 mg m - 3 ;P bias = 29.6 % yr P = 0.4 con p < 0.05 ), Chla-a ( RMSE = 0.23 mg m - 3 ;P bias = - 4.3 % yr P = 0.94 con p < 0.05 ), and SST ( RMSE = 2 . 3 ∘ C ;P bias = - 2.2 % yr P = 0.92 con p < 0.05 ) establish that although in some cases there was a slight over/underestimation, the satellite estimates consistently represent the variability and average values measured in situ. On the other hand, the spatio-temporal analysis of the POC allowed us to identify two seasons with their respective transition periods and five subregions in which the POC is characterized by having its maximum variability; two of these coincide with the locations of the eddies reported for the winter and summer seasons in the LPB, while the following three are located: one in the coastal zone and in the two areas in which the LPB interacts with the GC. The associations, variability nodes, and multiple linear regression analysis suggest that POC fluctuations in the LPB respond mainly to biological processes and, to some extent, to the seasonality of SST and wind. Finally, our results justify the use of the MODIS-Aqua satellite POC for studies in marine-coastal water bodies with similar characteristics to the LPB and suggest that this water body can be considered a reservoir for the marine region of northwestern Mexico.

Medical phototherapy in childhood skin diseases

Phototherapy is used for the medical care of cutaneous conditions that do not respond to topical or systemic medical agents, and for conditions that require broad exposure to UV as a stabilizing agent for disease. Numerous wavelengths and delivery devices of ultraviolet light are used in childhood. This article is a brief overview of the medical usage of phototherapy in childhood. In the neonatal nursery blue light (459-460 nm) is used to reduce bilirubin levels and prevent kernicterus. While psoralens and UVA (PUVA) has been demonstrated to be efficacious in a variety of pediatric skin conditions, narrowband UVB therapy (311 nm) has largely replaced psoralens and UVA as initial choice in full-body phototherapy for children. The latter is easier to deliver, with less resultant erythema than systemic psoralens and UVA which requires strict use of 24 hour protective eyewear. Narrowband UVB is therefore preferred for stabilization and clearance of a variety of inflammatory and autoimmune conditions especially atopic dermatitis, psoriasis and vitiligo. Conditions with lymphocytic infiltration, including mycosis fungoides, alopecia areata and pityriasis lichenoides can improve with Narrowband UVB as well. Alternatively, localized delivery of Narrowband UVB can be performed using the excimer laser (308 nm), which has been described for the therapy of vitiligo and alopecia areata in childhood. Some diseases with dermal infiltration including morphea and mastocytosis may do better with Psoralens and UVA or UVA1. Delivery of psoralens can also be performed topically for said conditions and in the setting of alopecia areata, thereby limiting UVA exposure, while retaining efficacy. Phototherapy can be a helpful adjunct in pediatric skin disease, but is limited by compliance issues. Parents can act as partners in the safe and effective delivery of phototherapy by standing outside the booth or inside with the child to ensure lack of movement and to aid in maintenance of eyewear. Choice of type of phototherapy and close monitoring, with parental partnership, is the key to successful treatment.

First Observations of Benthos and Seston from a Submersible in the Lower St. Lawrence Estuary

Six dives with the submersible PISCES IV have permitted a unique description of the benthic and pelagic environments of a large, deep Canadian estuary. The estuarine floor and continental slopes are divided into five depth-dependent benthic zones. In order of decreasing depth are the Bathyal Trough Zone, the lnfaunal Zone, the Ophiura Zone, the Ice Rafting Zone and the Wave Base Zone. The zonal boundaries are based on changes in the faunal community, sediment texture, current energy, level of bioturbation and suspended particulate loading. Biological resuspension appears important in the Bathyal Trough and lnfaunal Zones. Current resuspension dominates the Ophiura and Ice Rafting Zones with storm waves additionally reworking the Wave-Base sediments. Seston characteristics are strongly influenced by the source and dynamics of the host water mass. The Surface Layer, the entrained outflow from the St. Lawrence River, is the source of most suspended matter found beneath. Large particles, mostly organo-mineral aggregates, become even larger with depth and indicate a rapid downward transfer of suspended sediment. The upper Intermediate Layer is complicated by stratified zones of turbulence that temporarily reduce the floe size. With the absence of such fine water structure, the lower Intermediate Layer is characterized by long chains of marine "snow" joined by delicate filaments. The Bottom Layer, a zone of increased turbulence, had aggregates breaking up into a haze of fine particles.

Is the functional decline of Parkinson's disease similar to the functional decline of Alzheimer's disease?

Since many Parkinson's disease (PD) subjects develop dementia, we determined whether the correlation between functional and cognitive decline seen in Alzheimer's disease (AD) is seen in PD. Seventy-five PD subjects with and without dementia and 103 AD/MCI subjects underwent the Functional Assessment Staging (FAST), the Global Deterioration Scale (GDS), the UPDRS motor portion, and the MMSE. In AD/MCI subjects, changes in FAST and GDS scores correlated with MMSE (rho=-0.814, P<0.001; rho=-0.840, P<0.001, respectively). In PD subjects, the FAST and GDS also correlated with MMSE (rho=-0.675, P<0.001; rho=-0.647, P<0.001, respectively). The UPDRS correlated with the GDS and FAST more closely in PD than in AD. Similar to AD, functional declines in PD correlates with cognitive decline and may be influenced by motor disability in PD.

Cognitive decline in high-functioning older adults: reserve or ascertainment bias?

The detection of mild cognitive impairment and dementia in high-functioning older adults can be difficult. It has also been observed that high-functioning persons show a lower prevalence of dementia than low-functioning persons. Three alternative explanations for this observation have been proposed in the literature: brain reserve capacity (BRC), cognitive reserve, and ascertainment bias. With data from a prospective, population-based study of incident dementia, the Canadian Study of Health and Aging (CSHA), we classified participants as being high- (HF) or low-functioning (LF) in three ways: educational and occupational attainment, and estimated premorbid IQ. We observed that fewer HF older adults were diagnosed with dementia after five years, which is in accordance with both the BRC and cognitive reserve models. Contrary to expectations, no difference on rate of memory deterioration was observed between those HF and LF persons who exhibited mild cognitive impairment at CSHA-1. However, HF persons who subsequently were diagnosed with dementia (CSHA-2) showed more rapid decline on five of the six memory measures over time than did LF persons diagnosed with dementia at CSHA-2. When performance on measures of memory functioning at CSHA-1 was examined for highly educated older adults, significantly more of those with dementia at CSHA-2 (n = 59) had scores falling within or below the average range in comparison to normative standards than those who continued to show no cognitive impairment (n = 145). Our findings suggest that the lower incidence of dementia for HF persons may be primarily the result of ascertainment bias, not underlying differences in brain or cognitive reserve.

Vertical Flux of Biogenic Carbon in the Ocean: Is There Food Web Control?

Models of biogenic carbon (BC) flux assume that short herbivorous food chains lead to high export, whereas complex microbial or omnivorous food webs lead to recycling and low export, and that export of BC from the euphotic zone equals new production (NP). In the Gulf of St. Lawrence, particulate organic carbon fluxes were similar during the spring phytoplankton bloom, when herbivory dominated, and during nonbloom conditions, when microbial and omnivorous food webs dominated. In contrast, NP was 1.2 to 161 times greater during the bloom than after it. Thus, neither food web structure nor NP can predict the magnitude or patterns of BC export, particularly on time scales over which the ocean is in nonequilibrium conditions.

Aging and the skin

Several pathologic processes of the skin are seen more commonly in the elderly, so these patients need special attention. The skin undergoes physiologic and structural changes as it ages, and knowledge of these changes is essential to accurately interpret the physical signs and symptoms that may be present in the elderly patient. Since cutaneous inflammatory responses and subjective sensations may be diminished in aged skin, a higher degree of vigilance in physical examination is needed to reach a proper diagnosis. Prevention of many of the cutaneous signs of aging and of most skin cancers is dependent upon sun avoidance. Thus, the best advice physicians can offer patients of any age is to limit sun exposure by using a sunscreen with a high sun-protection factor, to avoid being in the sun during the peak tanning hours (between 10:00 AM and 2:00 PM), and to wear protective clothing when exposed to the sun.