Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Insights into volcanic hazards and plume chemistry from multi-parameter observations: the eruptions of Fimmvörðuháls and Eyjafjallajökull (2010) and Holuhraun (2014-2015)

The eruptions of Eyjafjallajökull volcano in 2010 (including its initial effusive phase at Fimmvörðuháls and its later explosive phase from the central volcano) and Bárðarbunga volcano in 2014-2015 (at Holuhraun) were widely reported. Here, we report on complementary, interdisciplinary observations made of the eruptive gases and lavas that shed light on the processes and atmospheric impacts of the eruptions, and afford an intercomparison of contrasting eruptive styles and hazards. We find that (i) consistent with other authors, there are substantial differences in the gas composition between the eruptions; namely that the deeper stored Eyjafjallajökull magmas led to greater enrichment in Cl relative to S; (ii) lava field SO2 degassing was measured to be 5-20% of the total emissions during Holuhraun, and the lava emissions were enriched in Cl at both fissure eruptions-particularly Fimmvörðuháls; and (iii) BrO is produced in Icelandic plumes in spite of the low UV levels.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11069-023-06114-7.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

The LDL receptor binding domain of apolipoprotein E directs the relative orientation of its C-terminal segment in reconstituted nascent HDL

Apolipoprotein E (apoE) (299 residues) is a highly helical protein that plays a critical role in cholesterol homeostasis. It comprises a four-helix bundle N-terminal (NT) and a C-terminal (CT) domain that can exist in lipid-free and lipid-associated states. In humans, there are two major apoE isoforms, apoE3 and apoE4, which differ in a single residue in the NT domain, with apoE4 strongly increasing risk of Alzheimer's disease (AD) and cardiovascular diseases (CVD). It has been proposed that the CT domain initiates rapid lipid binding, followed by a slower NT domain helix bundle opening and lipid binding to yield discoidal reconstituted high density lipoprotein (rHDL). However, the contribution of the NT domain on the CT domain organization in HDL remains poorly understood. To understand this, we employed Cys-specific cross-linking and spatially-sensitive fluorophores in the NT and CT domains of apoE3 and apoE4, and in isolated CT domain. We noted that the helices in isolated CT domain are oriented parallel to those in the neighboring molecule in rHDL, whereas full length apoE3 and apoE4 adopt either an anti-parallel or hairpin-like organization. It appears that the bulky NT domain determines the spatial organization of its CT domain in rHDL, a finding that has significance for apoE4, which is more susceptible to proteolytic cleavage in AD brains, showing increased accumulation of neurotoxic NT and CT fragments. We envisage that the structural organization of HDL apoE would have profound functional consequences in its ability to regulate cholesterol homeostasis in AD and CVD.

Ewe breed differences in cervical anatomy and cervicovaginal mucus properties: An international study

In sheep, cervical artificial insemination (AI) involves depositing semen at the cervical opening, as it is not possible to traverse the cervix due to its complex anatomy. However, internationally this method yields low pregnancy rates when frozen-thawed semen is used. An exception to this is in Norway, in which vaginal deposition of frozen-thawed semen to a natural estrus yields pregnancy rates around 70%. As the cervix and its secretions are the principal factors influencing sperm transport to the site of fertilization the aim of this study was to characterise the differences in the cervical anatomy as well as the cervicovaginal mucus properties of six European ewe breeds across three countries known to have differences in pregnancy rates following cervical AI with frozen-thawed semen. These were Suffolk and Belclare in Ireland, Fur and Norwegian White Sheep (NWS) in Norway and Ile de France and Romanov in France (n = 28-30 ewes/breed). Cervicovaginal mucus was collected at the follicular and luteal phases of both a synchronized and natural cycle and assessed for mucus weight, viscosity and colour. The anatomical characteristics of the cervix (length of the cervix, number of cervical rings and the appearance of the external os) were assessed post-mortem. There was a type of the cycle by ewe breed interaction represented by no differences in mucus production between ewe breeds at the natural cycle for both the follicular and luteal phases of the cycle. However, there were differences between ewe breeds at the synchronized cycle (P < 0.05). Belclare had the lowest mucus production at the follicular phase while NWS had the lowest amount of mucus at the luteal phase of the synchronized cycle. Overall, across all ewe breeds, mucus production was higher at the follicular than at the luteal phase (P < 0.05). Despite reports of Suffolk and NWS having the most divergent pregnancy rates following cervical AI with frozen-thawed semen, both breeds had the lowest overall mucus viscosity at the follicular phase of both types of cycle with no differences between both ewe breeds (P > 0.05). The length of the cervix, number of cervical rings and the external os type were affected by ewe breed (P < 0.05). Suffolk ewes had longer cervices but lower number of cervical rings than NWS and Fur ewes (both with higher pregnancy rates). In conclusion, while mucus production and mucus viscosity was affected by breed, these changes are not consistent with the known differences between ewe breeds in their pregnancy rates following cervical AI with frozen-thawed semen.

A Case study of the radiation therapy treatment of a transitional cell carcinoma of the distal urethra

Urethral carcinoma is a rare urological cancer, accounting for only 1% of malignancies in Australia. The most common histology is transitional cell carcinoma (TCC). The majority of these cancers are treated with surgery. The main purpose of this case study is to describe a novel radiation treatment technique for treatment of this uncommon cancer. This report details organ-preserving treatment for a distal penile urethral cancer using definitive radiation therapy (RT). In May 2016 a 69-year-old male presented to Crown Princess Mary Cancer Centre (CPMCC) with a small TCC of the distal urethra. The patient was offered numerous treatment options, both radical and organ-preserving approaches, and came to a final decision of a course of radiation therapy despite the lack of randomised evidence to guide treatment in this setting. A dose of 66 Gy in 33 fractions from parallel opposed lateral beams was prescribed to the distal penile urethra. This case required an unusual approach to patient set up to allow access for accurate treatment delivery and to maintain patient comfort. The patient tolerated the full course of radiation therapy with expected skin side effects. He has maintained adequate penile function and is currently free from disease at 33 months with ongoing clinical follow-up.

The 2011 eruption of Nabro volcano, Eritrea: perspectives on magmatic processes from melt inclusions

The 2011 eruption of Nabro volcano, Eritrea, produced one of the largest volcanic sulphur inputs to the atmosphere since the 1991 eruption of Mt. Pinatubo, yet has received comparatively little scientific attention. Nabro forms part of an off-axis alignment, broadly perpendicular to the Afar Rift, and has a history of large-magnitude explosive silicic eruptions, as well as smaller more mafic ones. Here, we present and analyse extensive petrological data obtained from samples of trachybasaltic tephra erupted during the 2011 eruption to assess the pre-eruptive magma storage system and explain the large sulphur emission. We show that the eruption involved two texturally distinct batches of magma, one of which was more primitive and richer in sulphur than the other, which was higher in water (up to 2.5 wt%). Modelling of the degassing and crystallisation histories demonstrates that the more primitive magma rose rapidly from depth and experienced degassing crystallisation, while the other experienced isobaric cooling in the crust at around 5 km depth. Interaction between the two batches occurred shortly before the eruption. The eruption itself was likely triggered by recharge-induced destabilisation of vertically extensive mush zone under the volcano. This could potentially account for the large volume of sulphur released. Some of the melt inclusions are volatile undersaturated, and suggest that the original water content of the magma was around 1.3 wt%, which is relatively high for an intraplate setting, but consistent with seismic studies of the Afar plume. This eruption was smaller than some geological eruptions at Nabro, but provides important insights into the plumbing systems and dynamics of off-axis volcanoes in Afar.

Daily routines of breastfeeding mothers

BACKGROUND

Increasing research suggests breastfeeding has many benfeits to mothers and children, yet breastfeeding duration rates remain well below Healthy People 2020 objectives. In order to increase breastfeeding rates, the complex role change in becoming a breastfeeding mother deserves closer examination.

OBJECTIVE

This pilot study sought to explore the daily routines and supports experienced by primiparous breastfeeding mothers with the objective of using this information to design interventions to promote breastfeeding duration.

METHODS

Surveys were conducted at 2-3, 6-8, and 10-12 weeks postpartum. Data were analyzed using quantitative and qualitative methods.

PARTICIPANTS

Eleven primiparous mothers.

RESULTS

None of the eleven mothers interviewed at 2-3 week had a daily routine; 5 out of 9 mothers described a 'hint of a routine' at 6-8 weeks, and 6 out of 7 mothers described an 'emerging routine' at 10-12 weeks. Despite wanting more support and better preparation, most mothers succeeded with exclusive breastfeeding for the 12-week period.

CONCLUSIONS

These findings were viewed through the lens of non-linear dynamics and transition theory. Implications for occupational therapy and occupational science were discussed.

Quantifying gas emissions from the "Millennium Eruption" of Paektu volcano, Democratic People's Republic of Korea/China

Paektu volcano (Changbaishan) is a rhyolitic caldera that straddles the border between the Democratic People's Republic of Korea and China. Its most recent large eruption was the Millennium Eruption (ME; 23 km³ dense rock equivalent) circa 946 CE, which resulted in the release of copious magmatic volatiles (H₂O, CO₂, sulfur, and halogens). Accurate quantification of volatile yield and composition is critical in assessing volcanogenic climate impacts but is challenging, particularly for events before the satellite era. We use a geochemical technique to quantify volatile composition and upper bounds to yields for the ME by examining trends in incompatible trace and volatile element concentrations in crystal-hosted melt inclusions. We estimate that the ME could have emitted as much as 45 Tg of S to the atmosphere. This is greater than the quantity of S released by the 1815 eruption of Tambora, which contributed to the "year without a summer." Our maximum gas yield estimates place the ME among the strongest emitters of climate-forcing gases in the Common Era. However, ice cores from Greenland record only a relatively weak sulfate signal attributed to the ME. We suggest that other factors came into play in minimizing the glaciochemical signature. This paradoxical case in which high S emissions do not result in a strong glacial sulfate signal may present a way forward in building more generalized models for interpreting which volcanic eruptions have produced large climate impacts.

Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow

Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption.

Review of cardiometabolic risk factors in a cohort of paediatric type 1 diabetes mellitus patients

BACKGROUND

Type 1 diabetes mellitus (T1DM) is a recognised risk factor for cardiometabolic disease. Other risk factors include age, gender, family history, glycaemic control, dyslipidaemia, weight, and activity levels.

AIMS

To estimate the point prevalence of cardiometabolic risk factors in a paediatric population with T1DM.

METHODS

Eighty-one patients with T1DM aged between 10 and 16 years attended during the study and 56 (69.1 %) patients agreed to participate. Mixed methods data collection included a questionnaire developed for this study, supplemented by retrospective and prospective data collected from the patient records.

RESULTS

Of 56 subjects with T1DM, aged 12.7 ± 1.7 years (10-16 years) 26 were male and 30 were female. Mean HbA1c was 72 ± 14 mmol/mol. 53 subjects (94.6 %) had at least one additional cardiometabolic risk factor.

CONCLUSIONS

Cardiometabolic risk factors are present in this population with T1DM. Identifying cardiometabolic risk factors in adolescent T1DM patients is the first step in prevention of future morbidity and mortality.

First recorded eruption of Nabro volcano, Eritrea, 2011

We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO₂ emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

Risk perceptions and trust following the 2010 and 2011 Icelandic volcanic ash crises

Eruptions at the Icelandic volcanoes of Eyjafjallajökull (2010) and Grimsvötn (2011) produced plumes of ash posing hazards to air traffic over northern Europe. In imposing restrictions on air traffic, regulators needed to balance the dangers of accidents or aircraft damage against the cost and inconvenience to travelers and industry. Two surveys examined how members of the public viewed the necessity of the imposed restrictions and their trust in different agencies as estimators of the level of risk. Study 1 was conducted with 213 British citizens (112 males, 101 females), who completed questionnaires while waiting for flights at London City Airport during May 2012. Study 2 involved an online survey of 301 Icelandic citizens (172 males, 127 females, 2 undeclared gender) during April 2012. In both samples, there was general support for the air traffic restrictions, especially among those who gave higher estimates of the likelihood of an air accident or mishap having otherwise happened. However, in both countries, the (minority of) respondents who had personally experienced travel disruption were less convinced that these restrictions were all necessary. Scientists, the International Civil Aviation Organization, and (in Iceland) the Icelandic Department of Civil Protection were all highly trusted, and seen as erring on the side of caution in their risk estimates. Airlines were seen as more likely to underestimate any risk. We conclude that perceptions of the balance between risk and caution in judgments under uncertainty are influenced by one's own motives and those attributed to others.

Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

INTRODUCTION

The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

METHODS

In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

RESULTS

Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

CONCLUSIONS

The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

The role of routine pre-operative bedside echocardiography in detecting aortic stenosis in patients with a hip fracture

The prevalence and severity of aortic stenosis in unselected patients admitted with a hip fracture is unknown. Derriford Hospital operates a routine weekday, pre-operative, targeted bedside echocardiography examination on all patients admitted with a hip fracture. We carried out a prospective service evaluation for 13 months from October 2007 on all 501 admissions, of which 374 (75%) underwent pre-operative echocardiography. Of those patients investigated, 8 (2%) had severe, 24 (6%) moderate and 113 (30%) had mild aortic stenosis or aortic sclerosis. Eighty-seven of 278 (31%) patients with no murmur detected clinically on admission had aortic stenosis on echocardiography and of the 96 patients in whom a murmur was heard pre-operatively, 30 (31%) had a normal echocardiogram. Detection of a murmur does not necessarily reflect the presence of underling aortic valve disease. However, if a murmur is heard then the likelihood of the lesion's being moderate or severe aortic stenosis is increased (OR 8.5; 95% CI 3.8-19.5). Forty-four (12%) of our unselected patients with fractured femur had either moderate or severe aortic stenosis (with or without moderate or severe left ventricular failure), or mild stenosis with moderately or severely impaired left ventricular function.

Quantum control by means of hamiltonian structure manipulation

A traditional quantum optimal control experiment begins with a specific physical system and seeks an optimal time-dependent field to steer the evolution towards a target observable value. In a more general framework, the Hamiltonian structure may also be manipulated when the material or molecular 'stockroom' is accessible as a part of the controls. The current work takes a step in this direction by considering the converse of the normal perspective to now start with a specific fixed field and employ the system's time-independent Hamiltonian structure as the control to identify an optimal form. The Hamiltonian structure control variables are taken as the system energies and transition dipole matrix elements. An analysis is presented of the Hamiltonian structure control landscape, defined by the observable as a function of the Hamiltonian structure. A proof of system controllability is provided, showing the existence of a Hamiltonian structure that yields an arbitrary unitary transformation when working with virtually any field. The landscape analysis shows that there are no suboptimal traps (i.e., local extrema) for controllable quantum systems when unconstrained structural controls are utilized to optimize a state-to-state transition probability. This analysis is corroborated by numerical simulations on model multilevel systems. The search effort to reach the top of the Hamiltonian structure landscape is found to be nearly invariant to system dimension. A control mechanism analysis is performed, showing a wide variety of behavior for different systems at the top of the Hamiltonian structure landscape. It is also shown that reducing the number of available Hamiltonian structure controls, thus constraining the system, does not always prevent reaching the landscape top. The results from this work lay a foundation for considering the laboratory implementation of optimal Hamiltonian structure manipulation for seeking the best control performance, especially with limited electromagnetic resources.

Oxford Miniature Vaporiser output with reversed gas flows

This study was undertaken to investigate and calibrate the isoflurane output of an Oxford Miniature Vaporiser (OMV) draw-over vaporiser with reversed gas flows. Plenum or Boyles type machines have gas flowing left to right through the apparatus. Draw over anaesthesia systems, in contrast, traditionally have the carrier gas, air plus oxygen, flowing right to left through the vaporiser. There are a number of variations in the external design of the OMV vaporiser: 1) a back bar mounted draw-over vaporiser with 23-mm taper and left to right gas flow, 2) the Tri-Service with 22-mm taper and left to right gas flow, and 3) the traditional draw-over OMV with right to left gas flow with a variety of tapers. Non-uniformity leads to a variety of possible connections. The predictable output of the OMV vaporiser assumes the correct direction of gas flows for the device. There are many second hand right to left OMV vaporisers for sale to developing countries where the nuances of vaporiser orientation add unnecessarily to the desired simplicity of anaesthesia. A simple calibration scale for reversed gas flows through the OMV vaporiser would be useful.

Resuspending ram spermatozoa in seminal plasma after cryopreservation does not improve pregnancy rate in cervically inseminated ewes

The role of seminal plasma (SP) components on the maintenance of motility, viability and fertilising ability of frozen-thawed spermatozoa is of considerable interest. However, differences observed in constituents of SP among males could explain differences in fertility obtained in vivo. Two experiments were designed to examine the effects of seminal plasma on fertility from cervically inseminated frozen-thawed semen. The objective of Experiment 1 was to investigate if source or type of SP influences pregnancy rate. Seminal plasma was collected from rams previously classified as having either High (HSP; n=3) or Low (LSP; n=3) fertility in vivo. Artificial SP (fructose/sodium solution with 10% BSA; ASP) was made. Frozen semen from the same 6 rams was thawed and inseminated (Control) or resuspended either in HSP, LSP or ASP (20% in semen) prior to insemination of ewes (n=284, over 2 farms). The overall pregnancy rate was 28.1%. Treatments (Control, ASP, HSP and LSP) were not significantly different (P>0.3). There was no difference between HSP and LSP (P>0.5), and no effect of using ASP compared to ram SP (P>0.7), on pregnancy rate. As there was no effect of SP on pregnancy rate a repeat experiment (Experiment 2) was designed to test the effect of washing and selecting motile sperm prior to resuspending in phosphate-buffered saline (PBS) containing SP on pregnancy rate. Frozen-thawed semen from each of 2 rams was centrifuged through a density gradient, pellets were centrifuged through a wash medium and the sperm concentration/ram was counted. Sperm cells were resuspended in: (1) control PBS, (2) PBS containing 30% HSP or (3) PBS containing 30% LSP to give 100 x 10(6) motile sperm in 0.25 mL. Control straws were thawed and inseminated directly. Ewes (n=223 over 2 farms) were inseminated 57 h post-sponge withdrawal and those not returning to oestrus were slaughtered 29-50 days post-insemination for pregnancy determination. In Experiment 2, the pregnancy rate for Control, PBS, HSP and LSP were 15.4%, 2.3%, 0% and 0%, respectively, for Farm 1 (P>0.05) and 17.8%, 11.0%, 3.9% and 12.4%, respectively, for Farm 2. Under the conditions of the current study, addition of SP from different donors of either High or Low fertility status to frozen-thawed ram semen post-thawing did not improve pregnancy rate in ewes. ASP had no effect on pregnancy rate in ewes when added to frozen-thawed semen. Washing and selection of motile sperm prior to resuspension in PBS with or without SP (30%) before insemination had a negative effect on pregnancy rate in cervically inseminated ewes. Hence, the addition of seminal plasma or some of its constituents to semen does not appear to improve pregnancy rate in cervically inseminated ewes.

Hormonal relationships during the periovulatory period among ewe breeds known to differ in fertility after cervical artificial insemination with frozen thawed semen

Our previous work indicates that ewe breed differences in fertility following cervical AI with frozen-thawed semen are due to failure of normal sperm transport and/or early embryo development. Here we examined differences in hormone concentrations about the time of ovulation among more (Finnish Landrace and Belclare) and less (Suffolk and Texel) fertile ewes after AI with frozen thawed semen. In Experiment 1, oestradiol concentrations were measured in samples collected frequently from 12h before to 18h after the LH surge and progesterone was measured in samples collected from 9 to 27h after the LH surge in Suffolk (n=24), Texel (n=20) and Finnish Landrace (n=27) ewes. In Experiment 2, oestradiol concentrations were measured in samples collected frequently from 24h before to 6h after the LH surge and progesterone was measured in samples collected from 6h to 6 days after the LH surge in Suffolk (n=35) and Belclare (n=30) ewes. In Experiment 1, there was an effect of breed, time and their interaction (P<0.001) on oestradiol concentrations between -12 and +6h but only breed differences at +12 and +18h (P<0.01). Progesterone concentrations increased over time (P<0.001) and the rate of increase was significantly greater in Finnish Landrace than in the other two breeds. In Experiment 2, oestradiol concentrations were unaffected by breed. There was an interaction between breed and time with the rate of increase of progesterone being greater in Belclare than Suffolk ewes (P<0.001). In conclusion, differences in hormone concentrations in the periovulatory period are not consistent with ewe breed differences in fertility; however, we have showed that progesterone concentrations rise earlier in the more prolific breeds and suggest that this may explain reported ewe breed differences in embryo development.

The difference in embryo quality between Belclare and Suffolk ewes is not due to differences in oocyte quality

We have previously reported that the percentage of fertilized oocytes which reached the blastocyst stage by Day 6 after AI with frozen-thawed semen was higher for Belclare (94%) than Suffolk (59%) ewes. This may reflect differences in the timing of fertilization (Experiment 1) or differences in oocyte quality (Experiments 2 and 3). In Experiment 1, oocytes recovered from slaughterhouse ovaries were matured in vitro for 18, 20, 24, 28 or 30 h prior to fertilization and were then cultured in vitro. In Experiment 2, Belclare (n = 69) and Suffolk (n = 71) ewes were laparoscopically inseminated using frozen-thawed semen. Presumptive zygotes were recovered between 23 and 47 h post-insemination and cultured in vitro (grouped by breed). In Experiment 3, immature oocytes from Suffolk and Belclare ewes, were matured, fertilized and cultured in vitro (grouped by breed). Cleavage rate and blastocyst development was assessed. There was no effect of time of fertilization on cleavage rate, however, a lower proportion of cleaved oocytes reached the blastocyst stage after insemination at 30h compared to 24 h (P < 0.001). Ewe breed did not affect cleavage rate of oocytes matured and fertilized in vivo (41+/-9.6 and 47+/-10.1) or in vitro (47+/-9.4 and 52+/-9.4) for Belclare and Suffolk ewes, respectively (P > 0.05; %+/-S.E.). Likewise, ewe breed had no effect on the percentage (+/-S.E.) of cleaved oocytes developing to the blastocyst stage for in vivo (29+/-7.2 and 25+/-7.9) or in vitro matured and fertilized oocytes (29+/-6.1 and 36+/-5.9) from Belclare and Suffolk ewes, respectively (P>0.05). Based on this study oocyte quality does not differ between the breeds and in addition a 4h difference in the timing of fertilization, reflective of the breed difference in the timing of the LH surge in vivo, would not affect early embryo development.

Relationship between in vitro fertilisation of ewe oocytes and the fertility of ewes following cervical artificial insemination with frozen-thawed ram semen

No laboratory test exists that can reliably predict differences among rams in field fertility after artificial insemination (AI) with frozen-thawed semen. In vitro fertilisation (IVF) has been proposed as a method of predicting these differences. The objectives of this study were to evaluate whether IVF system could discriminate among rams of different fertility in vivo after AI using frozen-thawed semen. Also, to examine effects of lowering sperm concentration on discrimination power between rams used for IVF. The aim of Experiment 1 was to evaluate the effect of altering the sperm concentration from 2 x 10(6) to 0.03125 x 10(6) spermatozoa/mL on subsequent cleavage rate and blastocyst rate in vitro. In Experiment 2, six rams (three High and three Low in vivo fertility; average pregnancy rates of 37.6% and 21.8%, respectively) were compared for their fertilising ability in IVF. Spermatozoa from each of the six rams were added to ewe oocytes using a concentration of either 2 x 10(6) or 0.0625 x 10(6)/mL. There were six replicates with 25 oocytes per well and two wells per ram per replicate. Cleavage rate was monitored at 48 h post-insemination (p.i.) and blastocyst rate determined on Days 6-8 p.i. In Experiment 1, cleavage rate increased with increasing sperm concentration and blastocyst rate was not affected by sperm concentration on any day. When the six rams were tested using 2 x 10(6) spermatozoa/mL, no significant differences were found between High and Low fertility groups for cleavage rate or blastocyst rate on Days 6, 7, or 8 p.i. (P>0.05). When the experiment was repeated using 0.0625 x 10(6) spermatozoa/mL, no differences were found between High and Low group rams for blastocyst rate on any of Days 6, 7 or 8 p.i. (P>0.05). However, there was a significant difference between High and Low fertility rams for percentage of oocytes cleaved (16.4, S.E. 2.02%; P<0.01) and the correlation between fertility in vivo and cleavage rate in vitro was significant (P=0.013). Replicate of IVF was a source of significant variation for both cleavage rate and blastocyst rate and conditions need to be further controlled. However, we suggest that using a low concentration of spermatozoa (0.0625 x 10(6)/mL) for IVF may be a useful method for predicting field fertility of frozen-thawed ram semen.

Differences between Belclare and Suffolk ewes in fertilization rate, embryo quality and accessory sperm number after cervical or laparoscopic artificial insemination

Ewe breed has been shown to have a major effect on pregnancy rates following cervical AI using frozen-thawed semen. The main objective of this study was to examine the differences between purebred Belclare and Suffolk ewes (multiparous) in fertilization rate, number of accessory sperm and stage of embryo development on day 6 after cervical or laparoscopic AI with frozen-thawed semen. In experiment 1, Belclare and Suffolk ewes were synchronized for 12 days and were either cervically inseminated (year 1: n=28 and 31; year 2: n=16 and 15, respectively) or laparoscopically inseminated (year 2: n=13 and 14). In experiment 2, superovulated Belclare (n=4) and Suffolk (n=13) ewes were laparoscopically inseminated. All ewes were slaughtered 6 days after AI; oocytes/embryos were recovered, morphologically graded and stained to assess the number of cells and accessory spermatozoa. Data from both experiments were combined for statistical analysis. The proportion of ewes with fertilized oocytes was significantly higher following laparoscopic AI compared with cervical AI (54% versus 19%). More Belclare than Suffolk ewes yielded fertilized oocyte(s) after cervical AI (34% versus 10%, P<0.02) but there was no difference after laparoscopic AI (62% versus 60%). From the ewes that yielded at least one fertilized oocyte the proportion of Belclare ewes with embryos at the morula/blastocyst stage was significantly greater than for Suffolk ewes (94% versus 59%, P<0.02). A higher proportion of Belclare than Suffolk ewes had evidence of sperm reaching the site of fertilization following cervical AI (39% versus 15%, P<0.02) but there was no difference after laparoscopic AI (62% versus 64%, P>0.8). Amongst the ewes with evidence of sperm at the site of fertilization, laparoscopic AI resulted in a higher number of sperm per oocyte/embryo or per ewe than cervical AI (P<0.01). These results suggested that the difference in pregnancy rate between Suffolk and Belclare ewes following cervical AI was due to: (i) sperm traversing the cervix and uterus in a higher proportion of Belclare than Suffolk ewes, leading to a higher incidence of fertilization and (ii) the lower developmental competence of fertilized oocytes from Suffolk ewes.

In vitro fertilization as a predictor of fertility from cervical insemination of sheep

The objective of this study was to determine if the quality of frozen-thawed ram semen could be effectively evaluated through in vitro fertilization (IVF) procedures prior to insemination as a means of improving pregnancy rate. In experiment 1, frozen semen from four Belclare rams was assessed using IVF and was used for cervical insemination of ewes (n = 181) in 13 pedigree Belclare flocks. There was a significant association between IVF score (proportion of oocytes cleaved at 48 h post insemination) and non-return rate (P < 0.001). For experiment 2, semen from nine Belclare rams was evaluated by IVF and semen from rams with the highest (n = 3) and lowest (n = 2) IVF scores was used for cervical insemination of ewes (n = 111) under experimental conditions. Differences in pregnancy rates between individual rams did not reach significance. Experiment 3 was designed to determine if differences detected between rams at field level could be accurately identified via IVF evaluation and involved frozen semen from eight Norwegian rams of known field fertility (non-return rates ranged from 45.7 to 73.8%). IVF score did not reflect the differences in field fertility. In the final experiment six of the eight Norwegian rams involved in experiment 3 were selected based on IVF score (three highest and three lowest) and their semen was used for cervical insemination (n = 90 ewes). While significant differences in pregnancy rate were found between individual rams (P < 0.02, range: 12.9-65.8%) they were not associated with IVF score. Ewe breed had a significant effect (P < 0.003) on pregnancy rate in both experiments 2 and 4. In conclusion, there was no evidence from this study that the evaluation of semen quality through IVF provided a useful predictor of pregnancy rate under field conditions. It may be that the IVF procedures as used routinely, which are essentially designed to maximize blastocyst yields rather than for detecting differences in fertilizing ability between batches of sperm, need to be modified.

Fertility in the ewe following cervical insemination with fresh or frozen-thawed semen at a natural or synchronised oestrus

Artificial insemination (AI) in sheep is currently limited by the poor fertility obtained following non-surgical intracervical insemination of frozen-thawed semen. An exception to this general finding is the non-return rate of around 58% reported for large scale on-farm AI in Norway. The objective of the present study was to determine if similar results could be obtained under Irish conditions. Comparisons were made between semen collected, and frozen, from rams in Norway (NOR) and Ireland (IRL). The effects of synchronisation and inseminator were also examined. Parous ewes (n=297) of various breed types were inseminated to a natural (N) or synchronised (S) oestrus with either fresh (from Irish rams) or frozen-thawed (IRL and NOR) semen. Ewes were randomly assigned, within breed, to the following treatment groups: (i) Fresh-N: n=28, (ii) Fresh-S: n=30, (iii) IRL-N: n=62, (iv) IRL-S: n=50, (v) NOR-N: n=68, (vi) NOR-S: n=59. Within each group, ewes were inseminated by an experienced Norwegian or by an Irish inseminator. Pregnancy rate did not differ significantly between ewes inseminated to a natural or synchronised oestrus nor between Norwegian and Irish frozen semen. The proportion of ewes pregnant after insemination with fresh semen was 0.82 and 0.70 (treatments i and ii) compared with 0.40, 0.52, 0.34 and 0.37 (treatments (iii)-(vi)) for frozen semen (P<0.001). Corresponding litter sizes (+/-S.E.), adjusted for ovulation rate, were 2.9+/-0.22, 3.3+/-0.23, 2.2+/-0.21, 1.7+/-0.21, 2.2+/-0.21 and 2.1+/-0.21 (fresh versus frozen; P<0.001). There was an interaction between semen type (fresh or frozen) and oestrus type (N or S) for litter size due to an increased adverse effect of frozen semen on litter size in synchronised ewes (P<0.05). Pregnancy rate was significantly influenced by breed of ewe (P<0.01) and inseminator (P<0.05). These results suggest that ewe breed may be a critical determinant of the potential for the exploitation of cervical insemination of frozen-thawed semen in sheep breeding programmes.

The association between lameness, ovarian cysts and fertility in lactating dairy cows

The objective of this observational study was to evaluate the association between lameness, ovarian cysts, and fertility in lactating dairy cows. Data analysis of historical records from a 3000 Holstein farm was conducted. Sixty-five cows that became lame within 30 days postpartum were used as cases, and 130 nonlame cows served as controls. The outcome variables were incidence of ovarian cysts (OC, %), conception rate at first service (CRFS, %), overall pregnancy rate (PR, %), and calving to first service interval (CFSI, day), Incidence of OC and CRFS were analyzed by logistic regression, PR by survival analysis and CFSI by ANOVA. Lame cows had a lower CRFS (17.5% versus 42.6%) and higher incidence of OC (25.0% versus 11.1%) than controls (P<or=0.05). Calving to first service interval was not different between lame and control cows (P>0.05). There was a multicollinearity relationship between lameness and ovarian cysts. The results show that cows that became lame within the first 30 days postpartum were associated with a higher incidence of ovarian cysts, a lower likelihood of pregnancy, and lower fertility than control cows. Because this is an observational study it is not possible to conclude a cause-effect relationship.

Metabolic responses of transition Holstein cows fed anionic salts and supplemented at calving with calcium and energy

The objective of this study was to determine the concentrations of plasma Ca, P, Mg, nonesterified fatty acids (NEFA), 3-hydroxybutyrate (BHBA), and glucose in transition cows fed anionic salts prepartum and provided with calcium and energy supplements at calving. The study was conducted on a Florida Holstein dairy farm from November to December 1997. Treatments consisted of no treatment (n = 30); 60 g of Ca as calcium chloride, orally (n = 30); 110 g of Ca as calcium propionate 510 g plus 400 g of propylene glycol, orally (n = 30); two doses of 60 g of Ca as calcium chloride, one at calving and the second 24 h later, orally (n = 30); and 10 g of Ca as borogluconate, intravenously (n = 30). Treatments were administered within 12 h after parturition. Blood samples were collected at d 1 (parturition), 2, 3, 6, 9, and 12 after calving. Plasma total Ca, P, Mg, NEFA, BHBA, and glucose were measured. There were no differences in the concentrations of the blood metabolites among treatments.

Autosomal-dominant hemochromatosis is associated with a mutation in the ferroportin (SLC11A3) gene

Hemochromatosis is a progressive iron overload disorder that is prevalent among individuals of European descent. It is usually inherited in an autosomal-recessive pattern and associated with missense mutations in HFE, an atypical major histocompatibility class I gene. Recently, we described a large family with autosomal-dominant hemochromatosis not linked to HFE and distinguished by early iron accumulation in reticuloendothelial cells. Through analysis of a large pedigree, we have determined that this disease maps to 2q32. The gene encoding ferroportin (SLC11A3), a transmembrane iron export protein, lies within a candidate interval defined by highly significant lod scores. We show that the iron-loading phenotype in autosomal-dominant hemochromatosis is associated with a nonconservative missense mutation in the ferroportin gene. This missense mutation, converting alanine to aspartic acid at residue 77 (A77D), was not seen in samples from 100 unaffected control individuals. We propose that partial loss of ferroportin function leads to an imbalance in iron distribution and a consequent increase in tissue iron accumulation.

Association between exposure to Neospora caninum and milk production in dairy cows

OBJECTIVE

To determine association between exposure to Neospora caninum and milk production in dairy cows.

DESIGN

Prospective observational study.

ANIMALS

565 Holstein cows.

PROCEDURE

Cows were classified as seropositive or seronegative to N. caninum within 7 days after calving by use of a kinetic ELISA. Milk production was compared between seropositive and seronegative cows.

RESULTS

On the basis of 305-day mature equivalent milk production data, seropositive cows produced less milk (2.8 lb/cow per day) than did seronegative cows. In addition, analysis of results throughout the first 300 days of lactation revealed that after adjusting for effects of lactation number, calving season, clinical mastitis, and lameness, milk weight of seropositive cows was 2.5 lb/cow per day less than that of seronegative cows.

CONCLUSIONS AND CLINICAL RELEVANCE

Exposure to N. caninum was associated with a 3 to 4% decrease in milk production. A decrease in milk production of 800 lb/cow for a typical 305-day lactation represents a loss of $128/cow.

Autosomal-dominant hemochromatosis is associated with a mutation in the ferroportin (SLC11A3) gene

Hemochromatosis is a progressive iron overload disorder that is prevalent among individuals of European descent. It is usually inherited in an autosomal-recessive pattern and associated with missense mutations in HFE, an atypical major histocompatibility class I gene. Recently, we described a large family with autosomal-dominant hemochromatosis not linked to HFE and distinguished by early iron accumulation in reticuloendothelial cells. Through analysis of a large pedigree, we have determined that this disease maps to 2q32. The gene encoding ferroportin (SLC11A3), a transmembrane iron export protein, lies within a candidate interval defined by highly significant lod scores. We show that the iron-loading phenotype in autosomal-dominant hemochromatosis is associated with a nonconservative missense mutation in the ferroportin gene. This missense mutation, converting alanine to aspartic acid at residue 77 (A77D), was not seen in samples from 100 unaffected control individuals. We propose that partial loss of ferroportin function leads to an imbalance in iron distribution and a consequent increase in tissue iron accumulation.

Effect of freezing rate of ram spermatozoa on subsequent fertility in vivo and in vitro

Ram spermatozoa are most susceptible to damage during freezing between the temperatures of -10 degrees C and -25 degrees C. The objectives of the present study were to examine how freezing rate through this critical temperature zone affected the fertility of spermatozoa as assessed in vivo and in vitro. Semen from six adult rams was frozen at two different rates ("fast": 5 degrees C/min from +5 to -25 degrees C; "slow": 0.5 degrees C/min from +5 to -25 degrees C). In Experiment 1, semen from the fast and slow treatments was used to fertilize ovine oocytes that had been matured in vitro. Semen from the fast treatment yielded a higher cleavage rate (57% vs. 26%; P<0.001) and more blastocysts per oocyte (28% vs. 13%, P<0. 001) than slow-frozen. No correlation was found between fertilizing ability and viability as assessed by fluorescent probes. Experiment 2 was designed to establish the conception rates following both cervical and intrauterine insemination of frozen-thawed semen from the same bank of semen as used in Experiment 1. Ewes were superovulated with FSH and inseminated by laparoscopy with frozen semen. A significant difference was found in the number of fertilized ova following embryo recovery (81.4% vs. 39.3%; P<0.001). In a further study, 119 mature cull ewes were inseminated following a 12-day synchronization treatment with frozen semen by either intrauterine (laparoscopic) or cervical insemination. Insemination with fast-frozen semen resulted in a significantly higher pregnancy rate (P<0.05) irrespective of method of insemination. The data show that freezing rate affects the proportion of spermatozoa that retain their fertilizing ability post-thawing. However, once fertilization has occurred, development to the blastocyst stage is independent of freezing rate.

Milk urea nitrogen and infertility in Florida Holstein cows

The objective of this study was to evaluate the association between milk urea nitrogen (MUN) and risk of nonpregnancy after first breeding in a commercial dairy herd in Florida. A total of 515 and 558 cows were classified as having high (17 to 25 mg/dl) or low MUN (6 to 16 mg/dl) within 30 d before first breeding; a total of 158 (30.6%) and 189 (33.8%) cows were diagnosed as pregnant, respectively. Logistic regression was used to evaluate the association between MUN and risk of nonpregnancy controlling for other variables associated with fertility (parity, calving season, breeding season). An interaction was found showing that cows with high MUN that were bred during the summer were 18 times (OR = 17.9; 95% CI = 10.0 to 31.7) at higher risk of nonpregnancy compared to cows with low MUN that were bred during the winter.

Positional cloning of zebrafish ferroportin1 identifies a conserved vertebrate iron exporter

Defects in iron absorption and utilization lead to iron deficiency and overload disorders. Adult mammals absorb iron through the duodenum, whereas embryos obtain iron through placental transport. Iron uptake from the intestinal lumen through the apical surface of polarized duodenal enterocytes is mediated by the divalent metal transporter, DMTi. A second transporter has been postulated to export iron across the basolateral surface to the circulation. Here we have used positional cloning to identify the gene responsible for the hypochromic anaemia of the zebrafish mutant weissherbst. The gene, ferroportin1, encodes a multiple-transmembrane domain protein, expressed in the yolk sac, that is a candidate for the elusive iron exporter. Zebrafish ferroportin1 is required for the transport of iron from maternally derived yolk stores to the circulation and functions as an iron exporter when expressed in Xenopus oocytes. Human Ferroportin1 is found at the basal surface of placental syncytiotrophoblasts, suggesting that it also transports iron from mother to embryo. Mammalian Ferroportin1 is expressed at the basolateral surface of duodenal enterocytes and could export cellular iron into the circulation. We propose that Ferroportin1 function may be perturbed in mammalian disorders of iron deficiency or overload.

Markers of follicle function in Belclare-cross ewes differing widely in ovulation rate

High prolificacy due to a gene that has a large effect on ovulation rate has been noted in Booroola and Inverdale ewes. High prolificacy in the Belclare breed (a composite developed from stocks selected for very large litter size or high ovulation rate) may be related to the segregation of two genes. The aims of this study were (i) to compare the morphological and functional features of ovulatory follicles from carriers (which could only be heterozygous for the genes of interest) and non-carriers, and (ii) to identify markers of the Belclare genes among secreted or cellular ovarian proteins. Belclare carrier ewes had more ovulatory follicles (4.9 +/- 0.4) than did non-carrier ewes (2.0 +/- 0.2) (P < 0.001). Ovulatory follicles from carriers were also smaller (4.4 +/- 0.1 mm versus 5.7 +/- 0.2 mm, P < 0.001) and contained a significantly reduced number of granulosa cells (P < 0.001). However, the proportion of proliferating granulosa cells in ovulatory follicles was similar in both groups. The in vitro secretion of steroids per follicle was only marginally lower in follicles from Belclare carriers compared with non-carriers. Furthermore, similar concentrations of steroidogenic enzymes were present in both groups, indicating that steroidogenic potential per granulosa cell is similar between carriers and non-carriers. Possible markers of the Belclare genes were identified among cellular proteins of follicular walls by two-dimensional PAGE and image analysis. Two spots at 78 and 49 kDa were always absent in samples from non-carriers. When secreted proteins in follicles from carriers were compared with those from non-carriers, two spots at 53 and 41 kDa were restricted to samples from carriers and three spots at 97, 91 and 45 kDa were unique to samples from non-carriers. Interestingly, the spot at 91 kDa is also affected by the Booroola gene.