Effects of Calcium-Loading on Egg Production in Ring-Necked Pheasants

Abstract: Ring-necked pheasants (Phasianus colchicus) are able to store dietary calcium as medullary bone, which they may mobilize for future eggshell synthesis. We define this mechanism as calcium-loading. Previous experiments on pheasants conducted to document the importance of calcium in limiting distribution did not account for calcium-loading. We hypothesized that calcium-loading could override experimental calcium treatments of the diet. We measured egg production, egg characteristics, and femoral mineral content for pheasants that were not calcium-loaded on 7 diets differing in calcium from 0.2% to 4.5% and compared these results to a similar study on calcium-loaded pheasants. We predicted that calcium-loaded pheasants would produce more eggs than those that were not calcium-loaded. We also predicted that there would be no significant difference between femur ash fractions in non-calcium-loaded pheasants, but that the ash fraction in calcium-loaded pheasants would differ significantly between the beginning and end of the experiment. Egg production was higher in calcium-loaded pheasants above 2% dietary calcium. Femur ash fraction was not different in non–calcium-loaded pheasants but differed significantly before and after the experiment and between high (>2%) and low (<2%) dietary levels in calcium-loaded pheasants. Calcium-loading may account for short-term persistence of captive pheasants introduced on calcium-poor soils, followed by their eventual population failure. Managers may improve survival of captive pheasants before introduction by surveying habitat for adequate calcium and by calcium-loading.     

SARS-CoV-2 spike variants exhibit differential infectivity and neutralization resistance to convalescent or post-vaccination sera

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The conservation and tourism development of World Natural Heritage sites: The current situation and future prospects of research

The conservation and tourism development of World Heritage (WH) sites has always been a key and urgent scientific issue to be solved urgently by academia and industry all over the world. An increasing number of researchers and practitioners are paying attention to this issue. However, there is a lack of a comprehensive literature review on this topic. To fill this gap, this study conducts a systematic literature review (SLR) based on 179 related studies retrieved from the Web of Science (WoS) and Google Scholar (GS) databases. Focusing on the research question of the conservation and tourism development of World Natural Heritage (WNH) sites, we built an SLR framework to implement the review process. First, quantitative research was conducted to analyse the annual numbers, content and continents of the published literature. Second, we classified and summarized the main progress and achievements from theoretical research, technical methods, model construction, monitoring and evaluating, and application demonstration. Finally, in view of the current research situation of the conservation and tourism development of WNH sites, we proposed eight key scientific issues to be solved and several directions for future research.     

Sustaining productivity gains in the face of climate change: A research agenda for US wheat

Wheat is a globally important crop and one of the “big three” US field crops. But unlike the other two (maize and soybean), in the United States its development is commercially unattractive, and so its breeding takes place primarily in public universities. Troublingly, the incentive structures within these universities may be hindering genetic improvement just as climate change is complicating breeding efforts. “Business as usual” in the US public wheat-breeding infrastructure may not sustain productivity increases. To address this concern, we held a multidisciplinary conference in which researchers from 12 US (public) universities and one European university shared the current state of knowledge in their disciplines, aired concerns, and proposed initiatives that could facilitate maintaining genetic improvement of wheat in the face of climate change. We discovered that climate-change-oriented breeding efforts are currently considered too risky and/or costly for most university wheat breeders to undertake, leading to a relative lack of breeding efforts that focus on abiotic stressors such as drought and heat. We hypothesize that this risk/cost burden can be reduced through the development of appropriate germplasm, relevant screening mechanisms, consistent germplasm characterization, and innovative models predicting the performance of germplasm under projected future climate conditions. However, doing so will require coordinated, longer-term, inter-regional efforts to generate phenotype data, and the modification of incentive structures to consistently reward such efforts.     

Convergence of Differentially Invaded Systems toward Invader-dominance: Time-lagged Invasions as a Predictor in Desert Fish Communities

To what extent do patterns of invasion in one region generalize to other regions? Answering this question is a key goal of invasion biology because it underlies whether we can make progress via comparative studies or must instead cope with a large set of unique cases. Here we quantify similarities and differences in the historical development of nonnative fish assemblages of two North American desert drainages, one with many nonnative fishes (Gila Basin, principally southwestern USA), and one with few (Yaqui Basin, principally northwestern Mexico). The two river basins are similar in size, physiography, and ecology, but because of differences in the timing of regional development, we hypothesized that richness and geographic spread of nonnative fishes in the Yaqui are time-lagged relative to the Gila, and that a slow, but steady increase of nonnative fish occurrence is underway in the Yaqui, similar to what has already occurred in the Gila. Using the comprehensive SONFISHES database, we found that increases in the regional richness of extant nonnative species over time have been roughly linear in both basins. Meanwhile, previously established species have continued to spread spatially, such that the cumulative number of reach records for nonnative species has increased roughly exponentially in both systems. The current status of nonnatives in the Yaqui is remarkably similar to what was evident from the Gila in the past at a comparable level of sampling effort. For all measures of invasion dynamics we examined, a time lag of ～ 40–50 years exists between the Gila and Yaqui. The majority of extant nonnative fishes are known piscivores, and many have high levels of parental care, a life history trait that affords considerable advantages over native fishes. These results predict that, absent strong action now, the presently abundant native fish fauna of the Yaqui may become increasingly imperiled over the next several years, with a future similar to the Gila, where most native fishes are either extirpated, threatened, or substantially reduced in range, at least partially due to nonnative fishes. We recommend immediate actions to identify and protect high priority portions of the Yaqui Basin from further nonnative fish invasion before further degradation occurs.     

Early Predictors of Gestational Diabetes Mellitus in IVF-Conceived Pregnancies

ObjectiveGestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcomes. This study aimed to identify early and reliable GDM predictors that would enable implementation of preventive and management measures.MethodsThe participants were a 28-week prospective cohort of in vitro fertilization (IVF)-conceived pregnant women (≤39 years, body mass index [BMI] 18.5-38 kg/m²) without a known history of diabetes mellitus. Fasting blood samples were analyzed at baseline (pre-IVF) and 12 weeks’ gestation for reproductive hormones, glucose, serum insulin, lipids, thyroid function, adiponectin, and lipopolysaccharide-binding protein. At 28 weeks, a 75-g oral glucose tolerance test was used to screen for GDM.ResultsFor the overall group at baseline, 22% had BMI ≥30 kg/m², 45% had polycystic ovary syndrome, 16% had hemoglobin A1C of 5.7% to 6.1%, and 14% had a past history of GDM. At 28 weeks of gestation (n = 158), 34 women had developed GDM and 124 had not. Significant baseline predictors of GDM onset included greater BMI (29.0 vs 25.8 kg/m²), older age (34 vs 32 years), higher levels of follicle-stimulating hormone/luteinizing hormone ratio (1.2 vs 1.0), hemoglobin A1C (5.5 vs 5.2%), insulin (10.6 vs 7.1 μIU/mL), homeostatic model assessment of insulin resistance (2.2 vs 1.7), total cholesterol (199 vs 171 mg/dL), and low-density lipoprotein cholesterol (123 vs 105 mg/dL), and lower triglyceride levels (74 vs 76 mg/dL). Significant 12-week GDM predictors included greater maternal weight gain (delta: 3.4 vs 1.5 kg) and higher levels of insulin (11.3 vs 7.6 μIU/mL), triglycerides (178 vs 120 mg/dL), and homeostatic model assessment of insulin resistance (2.3 vs 1.5). Twelve-week BMI is a predictor of GDM following adjustment for polycystic ovary syndrome status and maternal age.ConclusionWhile preconception maternal BMI, age, and follicle-stimulating hormone/luteinizing hormone ratio are predictors of subsequent development of GDM, early IVF-conceived gestational weight gain is the best predictor of GDM onset.     

Population Structure of Tundra Swans Wintering in Eastern North America

ABSTRACT Our objective was to determine whether there were subpopulations within the eastern population of tundra swans (Cygnus columbianus columbianus) wintering along the mid-Atlantic coast. Movement rates between regions were substantial enough to result in continual mixing of wintering birds. Thus, we were unable to identify distinct subpopulations based on exclusive use of specific wintering areas. These birds should therefore be monitored, and their harvest managed, as if they were one population.