Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow ...from tributary glaciers. However, ice‐shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel‐1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability.
Plain Language Summary
The Antarctic Ice Sheet (AIS) is losing mass, thereby contributing to sea level rise. Ice shelves, which are thick floating layers of glacier ice extending from the glaciers on land, buttress much of the AIS and protect it from even more mass loss. The stability of these ice shelves is threatened by meltwater ponds that form during the summer and may cause ice shelves to break up. Here, we present field observations from Antarctica of a buried meltwater lake drainage via vertical fractures. To detect the drainage event, we use radar observations collected in the field, along with surface height changes and radar images from satellites, from both before and after the drainage event. Our study improves the understanding of meltwater processes on Antarctic ice shelves, and implications of those processes on ice‐shelf stability.
Key Points
We present the first field observations of the rapid drainage of a buried lake via hydrofracture in Antarctica
Lake‐bed fractures are detected from ground penetrating radar prior to drainage and suggest the lake may have been preconditioned to drain
Remote sensing analysis of digital elevation model and Sentinel‐1 microwave image differences provide additional lake evolution information
A major unresolved issue is how the uterus influences infertility and subfertility in cattle. Serial embryo transfer was previously used to classify heifers as high-fertile (HF), subfertile (SF), or ...infertile (IF). To assess pregnancy loss, two in vivo-produced embryos were transferred into HF, SF, and IF heifers on day 7, and pregnancy outcome was assessed on day 17. Pregnancy rate was substantially higher in HF (71%) and SF (90%) than IF (20%) heifers. Elongating conceptuses were about twofold longer in HF than SF heifers. Transcriptional profiling detected relatively few differences in the endometrium of nonpregnant HF, SF, and IF heifers. In contrast, there was a substantial difference in the transcriptome response of the endometrium to pregnancy between HF and SF heifers. Considerable deficiencies in pregnancy-dependent biological pathways associated with extracellular matrix structure and organization as well as cell adhesion were found in the endometrium of SF animals. Distinct gene expression differences were also observed in conceptuses from HF and SF animals, with many of the genes decreased in SF conceptuses known to be embryonic lethal in mice due to defects in embryo and/or placental development. Analyses of biological pathways, key players, and ligand–receptor interactions based on transcriptome data divulged substantial evidence for dysregulation of conceptus–endometrial interactions in SF animals. These results support the ideas that the uterus impacts conceptus survival and programs conceptus development, and ripple effects of dysregulated conceptus–endometrial interactions elicit loss of the postelongation conceptus in SF cattle during the implantation period of pregnancy.
Despite uncertainty in all levels of analysis, recent and long-term changes in our climate point to the distinct possibility that greenhouse gas emissions have altered mean annual temperatures, ...precipitation and weather patterns. Modeling efforts that use doubled atmospheric CO^sub 2^ scenarios predict a 1-7°C mean global temperature increase, regional changes in precipitation patterns and storm tracks, and the possibility of "surprises" or sudden irreversible regime shifts. The general effects of climate change on freshwater systems will likely be increased water temperatures, decreased dissolved oxygen levels, and the increased toxicity of pollutants. In lotic systems, altered hydrologic regimes and increased groundwater temperatures could affect the quality of fish habitat. In lentic systems, eutrophication may be exacerbated or offset, and stratification will likely become more pronounced and stronger. This could alter food webs and change habitat availability and quality. Fish physiology is inextricably linked to temperature, and fish have evolved to cope with specific hydrologic regimes and habitat niches. Therefore, their physiology and life histories will be affected by alterations induced by climate change. Fish communities may change as range shifts will likely occur on a species level, not a community level; this will add novel biotic pressures to aquatic communities. Genetic change is also possible and is the only biological option for fish that are unable to migrate or acclimate. Endemic species, species in fragmented habitats, or those in east-west oriented systems will be less able to follow changing thermal isolines over time. Artisanal, commercial, and recreational fisheries worldwide depend upon freshwater fishes. Impacted fisheries may make it difficult for developing countries to meet their food demand, and developed countries may experience economic losses. As it strengthens over time, global climate change will become a more powerful stressor for fish living in natural or artificial systems. Furthermore, human response to climate change (e.g., increased water diversion) will exacerbate its already-detrimental effects. Model predictions indicate that global climate change will continue even if greenhouse gas emissions decrease or cease. Therefore, proactive management strategies such as removing other stressors from natural systems will be necessary to sustain our freshwater fisheries.PUBLICATION ABSTRACT
Essentials
Competing risk by death may lead to overestimation of venous thromboembolism (VTE) risk in cancers.
We assessed the risk of VTE in cancer with and without accounting for competing risk by ...death.
The risk of VTE was influenced by the mortality rate and the time since cancer diagnosis.
Competing risk by death should be taken into account when exploring VTE risk in cancer.
Summary
Background
Venous thromboembolism (VTE) is a common complication in cancer, and studies have suggested that aggressive cancers create the highest risk of VTE. However, competing risk by death may result in overestimation of VTE risk in patients with cancers associated with high mortality. Therefore, we estimated the risk of VTE by cancer site, accounting for the differential mortality between cancers.
Methods
The Scandinavian Thrombosis and Cancer cohort included 144 952 participants followed from 1993–1997 to 2008–2012. Incidence rates, cause‐specific hazard ratios (HRs) and subdistribution HRs (SHRs) were assessed for overall cancer and by cancer site according to time intervals since cancer diagnosis.
Results
During follow‐up, 14 272 subjects developed cancer, and 567 had cancer‐related VTE. In cause‐specific analyses, the VTE risk was highest in the first 6 months after cancer diagnosis (HR 17.5, 95% confidence interval CI 15.1–20.3), and declined rapidly thereafter. However, when mortality was taken into account, the risk was similar in the periods 6 months before (SHR 4.8, 95% CI 3.6–6.4) and 6 months after (SHR 4.6, 95% CI 3.9–5.4) cancer diagnosis. The range of the 2‐year cumulative VTE incidence rates was substantially narrowed for all cancer sites after competing risk by death was taken into account (from 1–10% to 1–4%).
Conclusion
VTE risk by cancer site was influenced by the mortality rate and the time since cancer diagnosis. Our findings suggest that the cancer itself is a major contributor to VTE risk, and that competing risk by death should be taken into account when VTE risk in cancer is explored.
Microplastics (MPs) have become a global issue as they are omnipresent in the ocean. Fish ingesting MPs through feed could be affected in their physiological function, e.g., disrupted enzyme ...production and function, reduction of feeding and reproductive failure. This study assessed the effects of feed containing naturally weathered MPs from the Oslofjord (Norway) on the reproductive physiology of Atlantic cod (Gadus morhua). Farmed cod broodstock were fed either control (C-diet) or feeds containing 1% microplastic (MP-diet) starting nine months prior to spawning, from June until May. No major differences were found between diet groups in overall biometrics or gonad histology. Sex steroid levels (testosterone, 11-ketotestosterone and 17β-estradiol) resulted in expected profiles increasing over time without any significant differences between treatments. Gene expression levels of the steroidogenic enzyme 20β-hydroxysteroid dehydrogenase (20β-hsd) and vitellogenin1 (vtg1) showed significant differences between dietary treatments with lower expression in the control group. This can be a direct effect of MPs, but endocrine disrupting effects of potentially leachable plastic additives cannot be completely ruled out. Thus, these enzymes could be indicators of exposure to contaminants that disrupt sexual maturation by affecting the production of primarily maturation-inducing steroid. Although the concentration of MPs employed in this study may not be high enough to elicit any observable short-term biological effects, the observed gene expression suggests that long-term consequences should be considered caused by an expected increase of MPs in marine environments.
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•Dietary inclusion of 1% weathered PE had no effect on digestion or fish biometrics.•No dietary effect on gonadal development, fecundity or on egg quality were observed.•Gene expression through the BPG-axis and plasma steroid analysis was normal.•Gonadal and liver gene expressions of 20β-hsd and vtg1 differed between the groups.
Essentials
Whether D‐dimer at incident venous thromboembolism (VTE) can predict recurrence‐risk is unknown.
We explored this association in 454 cancer‐free patients with a first lifetime VTE.
A low ...D‐dimer at first VTE diagnosis was associated with a low recurrence risk.
The association was predominant in patients with deep vein thrombosis and unprovoked VTE.
Click to hear Dr Cannegieter's presentation on venous thrombosis: prediction of recurrence
Summary
Background
Venous thromboembolism (VTE) is a common disease with a high recurrence rate. D‐dimer measured after cessation of anticoagulant therapy predicts recurrence, and is used to decide on treatment prolongation. However, whether D‐dimer measured at first VTE diagnosis can be used to assess recurrence‐risk is unknown.
Aims
To investigate the association between D‐dimer, measured at first VTE diagnosis and risk of recurrent VTE.
Methods
Information on clinical risk factors and laboratory markers were collected in 454 cancer‐free patients with a first VTE. Recurrent VTEs and deaths during follow‐up (1994–2012) were recorded.
Results
During a median follow‐up of 3.9 years, 84 patients experienced a recurrent VTE. The crude recurrence rate was 1.7 (95% confidence interval CI, 1.0–2.9) per 100 person‐years in the lower quartile of D‐dimer (≤ 1500 ng mL−1), and 4.9 (95% CI, 3.9–6.1) per 100 person‐years in the upper three quartiles combined, yielding an absolute risk difference of 3.2 per 100 person‐years. Patients with D‐dimer ≤ 1500 ng mL−1 had 54% lower recurrence‐risk than patients with D‐dimer > 1500 ng mL−1 (HR, 0.46; 95% CI, 0.25–0.82). The association was particularly pronounced among patients with unprovoked events and deep vein thrombosis, showing a 66% (HR, 0.34; 95% CI, 0.15–0.74) and 68% (HR, 0.32; 95% CI, 0.14–0.71) lower recurrence risk among patients with D‐dimer ≤ 1500 ng mL−1, respectively.
Conclusions
A low D‐dimer (≤ 1500 ng mL−1) measured at first VTE diagnosis was associated with a low recurrence risk, particularly among patients with DVT and unprovoked events. Our findings suggest that a clinical decision to avoid prolonged anticoagulant treatment could be considered based on low D‐dimer at the time of VTE diagnosis.
Water Poverty Hansen, Shirley J.
2017, 20201217, 2016, 2020-12-17
eBook
A water crisis on our immediate horizon is destined to hurt, even kill, millions of children, and the window of opportunity to do something about it is rapidly closing. There is, however, a glimmer ...of hope that could turn into rays of sunshine. Water is a commodity, and we have just come through some painful times dealing with the shortage of another commodity-energy. For those who lived through the "energy crisis," this book offers a brief trip down memory lane.
The emerging field of climate-change adaptation has experienced a dramatic increase in attention as the impacts of climate change on biodiversity and ecosystems have become more evident. Preparing ...for and addressing these changes are now prominent themes in conservation and natural resource policy and practice. Adaptation increasingly is viewed as a way of managing change, rather than just maintaining existing conditions. There is also increasing recognition of the need not only to adjust management strategies in light of climate shifts, but to reassess and, as needed, modify underlying conservation goals. Major advances in the development of climate-adaptation principles, strategies, and planning processes have occurred over the past few years, although implementation of adaptation plans continues to lag. With ecosystems expected to undergo continuing climate-mediated changes for years to come, adaptation can best be thought of as an ongoing process, rather than as a fixed endpoint.
The E12-14-012 experiment, performed in Jefferson Lab Hall A, has measured the $(e, e'p)$ cross section in parallel kinematics using a natural argon target. Here, we report the full results of the ...analysis of the data set corresponding to beam energy 2.222 GeV, and spanning the missing momentum and missing energy range $15 \lesssim p_m \lesssim 300$ MeV/c and $12 \lesssim E_m \lesssim 80$ MeV. The reduced cross section, determined as a function of $p_m$ and $E_m$ with $\approx$4\% accuracy, has been fitted using the results of Monte Carlo simulations involving a model spectral function and including the effects of final state interactions. The overall agreement between data and simulations turns out to be quite satisfactory ($\chi^2$/n.d.o.f.=1.9). Furthermore, the resulting spectral function will provide valuable new information, needed for the interpretation of neutrino interactions in liquid argon detectors.
Abstract
Background
Asymptomatic
Plasmodium
infections significantly drive malaria transmission and impact control and elimination strategies, but are largely uncharacterized. We investigated the ...prevalence and risk factors of asymptomatic malaria infections to inform malaria control strategies in Ghana.
Method
Five cross-sectional surveys were conducted at the end of the peak transmission season (August–September) on 4892 school children aged between 6 and 14 years in two distinct ecological settings in Ghana between 2013 and 2017. The study sites were Begoro (forest ecology) and Cape Coast (coastal ecology). The children were screened for malaria parasites by microscopic examination of Giemsa-stained thin and thick blood films. Hemoglobin levels were measured using the Hemocue HB analyzer. In addition, height was measured and the height-for-age z-scores estimated from the reference population defined by WHO to determine children who were stunted. Proportions of categorical and means of continuous variables were compared using Chi-square test and Student’s t-test respectively, and multivariable logistic regression was done to assess risk factors associated with asymptomatic infections.
Results
The overall prevalence of asymptomatic malaria in the school children was higher in Begoro compared to Cape Coast (27% (95% CI: 17, 24%) vs. 24% (95% CI: 17, 24%),
p
value = 0.04). The study recorded three species of
Plasmodium
(
Plasmodia falciparum, malariae
, and
ovale
) in both sites.
Plasmodium falciparum
was the predominant species, accounting for about 85% of infections in both study sites. The asymptomatic school children were more likely to be anaemic (OR = 2.01,
p
value< 0.001) and stunted in growth (OR = 1.46,
p
value< 0.001). Males carried more asymptomatic infection than females (OR = 1.18,
p
value = 0.015). School children aged 12–14 years had more asymptomatic infections than those aged 6–8 years (OR = 1.28,
p
value = 0.005).
Conclusion
There is a considerable burden of asymptomatic malaria in the two regions of Ghana, which is associated with males, older children, anaemia, and stunted growth in children, and may have implications for malaria control and elimination strategies in Ghana.
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