82 research outputs found
Effects of the Wetlands Reserve Program on Waterfowl Carrying Capacity in the Rainwater Basin Region of South-Central Nebraska
The purpose of this Conservation Effects Assessment Project (CEAP) assessment was to evaluate the energetic contribution of the Wetlands Reserve Program (WRP) for migratory waterfowl using the Rainwater Basin Wetland Complex (RWB). The RWB is located in south central Nebraska and encompasses 6,150 mi2 that is dominated by row crop agriculture. Historically, \u3e 204,000 acres of playa wetlands were scattered across this region, but currently, just over 40,000 acres of wetlands remain. Annually, an estimated 12.4 million migratory waterfowl use this region during fall and/or spring migrations. Although used with less intensity as a fall stopover, approximately 9.8 million birds use the region during spring migration. This concentration of waterfowl coupled with reduced wetland resources is hypothesized to be causing intense competition between individuals for necessary energetic resources. We developed a bio-energetic model to evaluate the landscapeโs capacity to provide energetic resources for migrating waterfowl. Two components are necessary to complete a bio-energetic model, the energetic requirements of the individuals using the region and the energy available in primary forage habitats. Once these values were determined the model allowed us to evaluate both landscape capacity and program specific contribution to regional waterfowl foraging capacity. In total the RWB needs to provide 24.1 billion kcal of energy for migratory waterfowl. Currently waste grain can meet all waterfowl energetic requirements using the RWB region. Although sufficient energetic resources exist, research has documented that food resources other than waste grain are required to meet all waterfowl nutritional requirements (essential amino acids, inorganic elements, and vitamins). We used previous research to estimate that 39% (9.5 billion) of the 24.1 billion kcal should be provided by wetland habitats. Prior to delivery of WRP, the RWB could provide 5.9 billion kcal of energy from wetland habitats. The WRP has supported restoration of approximately 3,050 acres of wetland and 1,050 acres of upland habitats in the RWB. These wetland acres represent an 8% increase in the total wetland base and provide an additional 789 million kcal of energy. The WRP program has increased total wetland forage capacity in the RWB by 13% compared to pre WRP conditions. Despite the additional WRP wetland acres, the RWB is still 3.0 billion kcal short of meeting migrating waterfowl wetland forage requirements. Analysis of average (2004), below average (2006), and above average (2007) precipitation years documented 8,900, 3,200, and 12,650 acres of flooded habitat, respectively. These flooded acres could provide approximately 13%, 4%, and 21% of the total wetland forage that would have been required. These results demonstrate that additional habitat from WRP and other conservation programs will be necessary to ensure sufficient habitat becomes available as a result of variable precipitation events. These results also show the importance of management of existing wetlands, including those tracts restored by WRP, to ensure optimal habitat conditions when wetlands become flooded. A hydrologic model documented that off-site hydrologic modifications can have a tremendous negative effect on RWB wetlands ability to pond water. In the future, additional resources will also be needed to restore hydrology to ensure that under average conditions RWB wetlands function
Effects of Multivitamin Supplementation on Heart Rate Response in Aerobically Untrained College Aged Students
Multivitamin use is increasingly prevalent in the US among most every population. Yet, previous research noted no performance benefits among individuals following a supplementation period. This study focused on the potential physiological benefits from a three week multivitamin supplementation period using 24 (20.9 ยฑ 2.6yr) aerobically untrained college aged students. Subjects were divided equally into three groups (placebo = PL, multivitamin = MV, control = CL) and asked to perform separate eight minute bouts of exercise, consisting of six min of moderate (60%VO2max) intensity followed immediately by two min of high (85%VO2max) intensity exercise on a cycle ergometer. Following the supplementation period, participants came back and performed the same exercise bout. Heart rates were measured with a POLAR Heart Rate monitor and recorded every two min. Data analysis, using ANOVA comparing the three groups, indicated a statistically significant HR interaction. Post hoc paired t-tests, comparing the pre/post supplementation tests of all groups, noted significant differences in HR between MV group during the 60% VO2 (p = 0.04) intensity bout, and approached significance at 85% VO2 (p = 0.10). No difference occurred for the CL group during either moderate or high intensity exercise. The results indicate that the introduction of a supplement, whether real or placebo, may have a physiological effect on the heart rate of aerobically untrained college students
Sodium bicarbonate ingestion and individual variability in time to peak pH
The aim of this study was to determine the individual variability in time to peak pH after the consumption of a 300mg.kg-1 dose of sodium bicarbonate (NaHCO3). Seventeen active males volunteered to participate in the study (mean ยฑ SD: age 21.38 ยฑ 1.5y; mass 75.8 ยฑ 5.8kg; height 176.8 ยฑ 7.6cm). Participants reported to the laboratory where a resting capillary blood sample was taken aseptically from the fingertip. After this, 300 mg.kg-1 of NaHCO3 in 400ml of water with 50ml of flavoured cordial was ingested. Participants then rested for 90 min during which repeated blood samples were procured at 10 minute intervals for 60 mins and then every 5 min until 90 min. Blood pH concentrations were measured using a blood gas analyser. Results suggested that time to peak pH (64.41ยฑ18.78 min) was highly variable with a range of 10-85 min and a coefficient of variation of 29.16%. A bi-modal distribution occurred, at 65 and 75 min. In conclusion, researchers and athletes, when using NaHCO3 as an ergogenic aid, should determine, in advance their time to peak pH to best utilise the added buffering capacity this substance allows
Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations
peer-reviewedBackground: Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland. Methods: The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population. Results and discussion: The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively. Conclusions: Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values
The microaerophilic microbiota of de-novo paediatric inflammatory bowel disease: the BISCUIT study
<p>Introduction: Children presenting for the first time with inflammatory bowel disease (IBD) offer a unique opportunity to study aetiological agents before the confounders of treatment. Microaerophilic bacteria can exploit the ecological niche of the intestinal epithelium; Helicobacter and Campylobacter are previously implicated in IBD pathogenesis. We set out to study these and other microaerophilic bacteria in de-novo paediatric IBD.</p>
<p>Patients and Methods: 100 children undergoing colonoscopy were recruited including 44 treatment naรฏve de-novo IBD patients and 42 with normal colons. Colonic biopsies were subjected to microaerophilic culture with Gram-negative isolates then identified by sequencing. Biopsies were also PCR screened for the specific microaerophilic bacterial groups: Helicobacteraceae, Campylobacteraceae and Sutterella wadsworthensis.</p>
<p>Results: 129 Gram-negative microaerophilic bacterial isolates were identified from 10 genera. The most frequently cultured was S. wadsworthensis (32 distinct isolates). Unusual Campylobacter were isolated from 8 subjects (including 3 C. concisus, 1 C. curvus, 1 C. lari, 1 C. rectus, 3 C. showae). No Helicobacter were cultured. When comparing IBD vs. normal colon control by PCR the prevalence figures were not significantly different (Helicobacter 11% vs. 12%, p = 1.00; Campylobacter 75% vs. 76%, p = 1.00; S. wadsworthensis 82% vs. 71%, p = 0.312).</p>
<p>Conclusions: This study offers a comprehensive overview of the microaerophilic microbiota of the paediatric colon including at IBD onset. Campylobacter appear to be surprisingly common, are not more strongly associated with IBD and can be isolated from around 8% of paediatric colonic biopsies. S. wadsworthensis appears to be a common commensal. Helicobacter species are relatively rare in the paediatric colon.</p>
New Oldowan locality Sare-Abururu (ca. 1.7 Ma) provides evidence of diverse hominin behaviors on the Homa Peninsula, Kenya
The Homa Peninsula, in southwestern Kenya, continues to yield insights into Oldowan hominin landscape behaviors. The Late Pliocene locality of Nyayanga (โผ3โ2.6 Ma) preserves some of the oldest Oldowan tools. At the Early Pleistocene locality of Kanjera South (โผ2 Ma) toolmakers procured a diversity of raw materials from over 10 km away and strategically reduced them in a grassland-dominated ecosystem. Here, we report findings from Sare-Abururu, a younger (โผ1.7 Ma) Oldowan locality approximately 12 km southeast of Kanjera South and 18 km east of Nyayanga. Sare-Abururu has yielded 1754 artifacts in relatively undisturbed low-energy silts and sands. Stable isotopic analysis of pedogenic carbonates suggests that hominin activities were carried out in a grassland-dominated setting with similar vegetation structure as documented at Kanjera South. The composition of a nearby paleo-conglomerate indicates that high-quality stone raw materials were locally abundant. Toolmakers at Sare-Abururu produced angular fragments from quartz pebbles, representing a considerable contrast to the strategies used to reduce high quality raw materials at Kanjera South. Although lithic reduction at Sare-Abururu was technologically simple, toolmakers proficiently produced cutting edges, made few mistakes and exhibited a mastery of platform management, demonstrating that expedient technical strategies do not necessarily indicate a lack of skill or suitable raw materials. Lithic procurement and reduction patterns on the Homa Peninsula appear to reflect variation in local resource contexts rather than large-scale evolutionary changes in mobility, energy budget, or toolmaker cognition
The Reproducibility of Blood Acid Base Responses in Male Collegiate Athletes Following Individualised Doses of Sodium Bicarbonate: A Randomised Controlled Crossover Study
Background: Current evidence suggests sodium bicarbonate (NaHCO3) should be ingested based upon the individualised alkalotic peak of either blood pH or bicarbonate (HCO3โ) because of large inter-individual variations (10โ180 min). If such a strategy is to be practical, the blood analyte response needs to be reproducible. Objective: This study aimed to evaluate the degree of reproducibility of both time to peak (TTP) and absolute change in blood pH, HCO3โ and sodium (Na+) following acute NaHCO3 ingestion. Methods: Male participants (n = 15) with backgrounds in rugby, football or sprinting completed six randomised treatments entailing ingestion of two doses of 0.2 gยทkgโ1 body mass (BM) NaHCO3 (SBC2a and b), two doses of 0.3 gยทkgโ1 BM NaHCO3 (SBC3a and b) or two control treatments (CON1a and b) on separate days. Blood analysis included pH, HCO3โ and Na+ prior to and at regular time points following NaHCO3 ingestion over a 3-h period. Results: HCO3โ displayed greater reproducibility than pH in intraclass correlation coefficient (ICC) analysis for both TTP (HCO3โ SBC2 r = 0.77, P = 0.003; SBC3 r = 0.94, P < 0.001; pH SBC2 r = 0.62, P = 0.044; SBC3 r = 0.71, P = 0.016) and absolute change (HCO3โ SBC2 r = 0.89, P < 0.001; SBC3 r = 0.76, P = 0.008; pH SBC2 r = 0.84, P = 0.001; SBC3 r = 0.62, P = 0.041). Conclusion: Our results indicate that both TTP and absolute change in HCO3โ is more reliable than pH. As such, these data provide support for an individualised NaHCO3 ingestion strategy to consistently elicit peak alkalosis before exercise. Future work should utilise an individualised NaHCO3 ingestion strategy based on HCO3โ responses and evaluate effects on exercise performance
Sodium bicarbonate supplementation improves severe-intensity intermittent exercise under moderate acute hypoxic conditions
Acute moderate hypoxic exposure can substantially impair exercise performance, which occurs with a concurrent exacerbated rise in hydrogen cation (H+) production. The purpose of this study was therefore, to alleviate this acidic stress through sodium bicarbonate (NaHCO3) supplementation and determine the corresponding effects on severe intensity intermittent exercise performance. Eleven recreationally active individuals participated in this randomised, double-blind, crossover study performed under acute normobaric hypoxic conditions (FiO2% = 14.5%). Pre-experimental trials involved the determination of time to attain peak bicarbonate anion concentrations ([HCO3-]) following NaHCO3 ingestion. The intermittent exercise tests involved repeated 60 s work in their severe intensity domain and 30 s recovery at 20 W to exhaustion. Participants ingested either 0.3 gยทkg bm-1 of NaHCO3 or a matched placebo of 0.21 gยทkg bm-1 of sodium chloride prior to exercise. Exercise tolerance (+110.9 ยฑ 100.6 s; 95% CI: 43.3 to 178 s; g = 1.0) and work performed in the severe intensity domain (+5.8 ยฑ 6.6 kJ; 95% CI: 1.3 to 9.9 kJ; g = 0.8) were enhanced with NaHCO3 supplementation. Furthermore, a larger post-exercise blood lactate concentration was reported in the experimental group (+4 ยฑ 2.4 mmolยทl-1; 95% CI: 2.2 to 5.9; g = 1.8), while blood [HCO3-] and pH remained elevated in the NaHCO3 condition throughout experimentation. In conclusion, this study reported a positive effect of NaHCO3 under acute moderate hypoxic conditions during intermittent exercise and therefore, may offer an ergogenic strategy to mitigate hypoxic induced declines in exercise performance
Role of CBP and SATB-1 in Aging, Dietary Restriction, and Insulin-Like Signaling
Increased transcriptional complex activity, or pharmacological mimics of increased complex activity, predict lifespan in mice and mediate the protective effects of dietary restriction during aging
The Homeobox Protein CEH-23 Mediates Prolonged Longevity in Response to Impaired Mitochondrial Electron Transport Chain in C. elegans
Recent findings indicate that perturbations of the mitochondrial electron transport chain (METC) can cause extended longevity in evolutionarily diverse organisms. To uncover the molecular basis of how altered METC increases lifespan in C. elegans, we performed an RNAi screen and revealed that three predicted transcription factors are specifically required for the extended longevity of mitochondrial mutants. In particular, we demonstrated that the nuclear homeobox protein CEH-23 uniquely mediates the longevity but not the slow development, reduced brood size, or resistance to oxidative stress associated with mitochondrial mutations. Furthermore, we showed that ceh-23 expression levels are responsive to altered METC, and enforced overexpression of ceh-23 is sufficient to extend lifespan in wild-type background. Our data point to mitochondria-to-nucleus communications to be key for longevity determination and highlight CEH-23 as a novel longevity factor capable of responding to mitochondrial perturbations. These findings provide a new paradigm for how mitochondria impact aging and age-dependent diseases
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