21 research outputs found
Value of Private Lands Managed for Wild Northern Bobwhites in the Deep South
Successful northern bobwhite (Colinus virginiaus) management creating huntable bobwhite populations in the southeastern United States is largely practiced on private lands. These properties not only support high density bobwhite populations, they also support biodiversity including many declining or endangered species associated with frequently-burned pine savannas. The private land model has proven sustainable over centuries and has recently increased with \u3e20,000 ha of wild bobwhite lands added in Georgia, Florida, and South Carolina since 2000. The NBCI recognizes private lands are critical to restoration of bobwhites but, despite their conservation value, no studies have quantified areas under wild bobwhite management. We mapped 259 properties totaling ~ 345,614 ha with wild bobwhite management principally in Georgia, Florida, Alabama, and South Carolina, and are completing mapping in Mississippi, Virginia, and North Carolina. Our survey data found management actions were consistent across these properties including maintaining open pine canopy, reducing hardwoods in upland areas, prescribed ïŹre on areas of appropriate sizes and distribution, year- round supplemental feeding, nest predator management, and conservative harvest rates. Adoption of these management practices are a result of long-term research demonstrating their efïŹcacy. Density of bobwhites on a property was related to landscape composition with lower densities on more fragmented sites. Properties in core areas surrounded by other managed properties often achieved bobwhite densities of 5â8 quail/ha. Bobwhite densities on smaller isolated properties densities were ~ 2.5 quail/ha during fall. Aspects of this successful management model may be useful to other private lands as well as public management areas focused on northern bobwhite
Effects of Supplemental Feeding on Breeding Season Home Ranges and Resource Selection of Northern Bobwhites
Providing supplemental food resources for northern bobwhite (Colinus virginanus) has been a common management practice for decades, but its impact on bobwhite home ranges sizes and space use has been debated. Between 2001 and 2007, we established a 397 ha fed study area on Tall Timbers Research Station, which received grain sorghum biweekly along a 19.5 km feed trail. An adjacent 465 ha area was treated as a control with no supplemental food resources. Radio-tagged wild bobwhites were located 3 â 5 times each week throughout the breeding season and we used these locations to calculate home ranges during early breeding season (15 April â 30 June) and late breeding season (1 July â 1 October). We also determined second and third order selection of a 10-m buffer area surrounding the supplemental feed trail using compositional analyses. In total, 552 and 286 bobwhite home ranges were calculated for early and late breeding seasons, respectively. We observed significantly smaller early breeding season home ranges on the fed area (xÌ = 12.3 ha, 95% CL ± 0.6) relative to the control (xÌ = 17.4 ha ± 1.9). Average length of feed trail within home ranges was 583 m and 710 m for early and late breeding season home ranges, respectively. The feed trail buffer area was 3 to 5% of all home ranges. Home range placement was not random with high selection preference for the feed trail buffer area. However, there was a low selection preference for the feed trail buffer area within home ranges. Average distances to the feed trail for bobwhite locations (xÌ = 64.4 m ± 16.1) was similar to random locations (xÌ = 74.4 m ± 16.9). The effect of supplemental feeding on bobwhite home ranges size and resource use was greatest during the early breeding season when food and useable habitat were likely lower in availability. On our study area, supplemental food resources distributed along a feed trail impacted bobwhites during a critical transition period from the spring prescribed burning season to the early breeding season
Habitat Selection by Northern Bobwhite Broods in Pine Savanna Ecosystems
Habitat for northern bobwhite (Colinus virginianus) broods is a critical component of bobwhite management. Research within pine (Pinus spp.) savannas has provided contradictory results regarding the value of macro-habitats with studies demonstrating selection for annually-disked fallow fields and others showing avoidance of fields and selection for burned pine savannas. Field establishment (up to 30% of a property) is a published management recommendation for bobwhites in pine savannas but there are significant annual costs with fallow-field management; information on factors that influence habitat selection by broods can improve management recommendations and facilitate weighing costs/benefits. We examined 2nd and 3rd order habitat selection by 466 broods on 3 sites during 1999â2009. All sites had similar macro-habitats (e.g., pine savanna, fallow fields, hardwood drains) but differed in soil characteristics and species composition of ground vegetation. Annually-disked fields were preferred by broods in most years on sites with predominantly grass and hardwood scrub ground vegetation. Rainfall mediated use of hardwood drains and burned upland pine savannas; hardwood drains were used more during droughts whereas burned pine savannas were used more with increased rainfall. Burned upland pine savanna was preferred on higher fertility sites in 9 of 10 years at the 3rd order level, fields were avoided or used according to availability in 8 of 10 years, and drains were avoided. Managers should consider how soil, weather, and vegetation community in pine savannas influences habitat use by bobwhite broods when identifying the value of different macro-habitats. Field establishment may or may not provide brood habitat depending on site
Reduced GABAergic Neuron Excitability, Altered Synaptic Connectivity, and Seizures in a KCNT1 Gain-of-Function Mouse Model of Childhood Epilepsy.
Gain-of-function (GOF) variants in K+ channels cause severe childhood epilepsies, but there are no mechanisms to explain how increased K+ currents lead to network hyperexcitability. Here, we introduce a human Na+-activated K+ (KNa) channel variant (KCNT1-Y796H) into mice and, using a multiplatform approach, find motor cortex hyperexcitability and early-onset seizures, phenotypes strikingly similar to those of human patients. Although the variant increases KNa currents in cortical excitatory and inhibitory neurons, there is an increase in the KNa current across subthreshold voltages only in inhibitory neurons, particularly in those with non-fast-spiking properties, resulting in inhibitory-neuron-specific impairments in excitability and action potential (AP) generation. We further observe evidence of synaptic rewiring, including increases in homotypic synaptic connectivity, accompanied by network hyperexcitability and hypersynchronicity. These findings support inhibitory-neuron-specific mechanisms in mediating the epileptogenic effects of KCNT1 channel GOF, offering cell-type-specific currents and effects as promising targets for therapeutic intervention
Vitamin D pathway gene polymorphisms, diet, and risk of postmenopausal breast cancer: a nested case-control study
INTRODUCTION: Vitamin D receptor (VDR) polymorphisms have been inconsistently associated with breast cancer risk. Whether risk is influenced by polymorphisms in other vitamin D metabolism genes and whether calcium or vitamin D intake modifies risk by genotype have not been evaluated. METHODS: We conducted a nested case-control study within the Cancer Prevention Study II Nutrition Cohort of associations between breast cancer and four VDR single-nucleotide polymorphisms (SNPs), Bsm1,Apa1,Taq1, and Fok1, a poly(A) microsatellite, and associated haplotypes (baTL and BAtS). We also examined one SNP in the 24-hydroxylase gene (CYP24A1) and two in the vitamin D-binding protein (group-specific component [GC]) gene. Participants completed a questionnaire on diet and medical history at baseline in 1992. This study includes 500 postmenopausal breast cancer cases and 500 controls matched by age, race/ethnicity, and date of blood collection. RESULTS: Incident breast cancer was not associated with any genotype examined. However, women with the Bsm1 bb SNP who consumed greater than the median intake of total calcium (â„902 mg/day) had lower odds of breast cancer compared to women with the Bb or BB genotype and less than the median calcium intake (odds ratio 0.61, 95% confidence interval 0.38 to 0.96; p(interaction )= 0.01). Similar interactions were observed for Taq1 (T allele) and the poly(A) (LL) repeat. CONCLUSION: We found no overall association between selected vitamin D pathway genes and postmenopausal breast cancer risk. However, certain VDR gene polymorphisms were associated with lower risk in women consuming high levels of calcium, suggesting that dietary factors may modify associations by VDR genotype
Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTICâHF: baseline characteristics and comparison with contemporary clinical trials
Aims:
The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTICâHF) trial. Here we describe the baseline characteristics of participants in GALACTICâHF and how these compare with other contemporary trials.
Methods and Results:
Adults with established HFrEF, New York Heart Association functional class (NYHA)ââ„âII, EF â€35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokineticâguided dosing: 25, 37.5 or 50âmg bid). 8256 patients [male (79%), nonâwhite (22%), mean age 65âyears] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NTâproBNP 1971âpg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTICâHF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressureâ<â100âmmHg (n = 1127), estimated glomerular filtration rate <â30âmL/min/1.73 m2 (n = 528), and treated with sacubitrilâvalsartan at baseline (n = 1594).
Conclusions:
GALACTICâHF enrolled a wellâtreated, highârisk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation
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Use of Apatite for Chemical Stabilization of Subsurface Contaminants: Final Report
Groundwater at many Federal and civilian industrial sites is often contaminated with toxic metals at levels that present a potential concern to regulatory agencies. The U.S. Department of Energy (DOE) has some unique problems associated with radionuclides (primarily uranium), but metal contaminants most likely drive risk-based cleanup decisions, from the perspective of human health, in groundwater at DOE and U.S. Environmental Protection Agency (EPA) Superfund Sites include lead (Pb), arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), zinc (Zn), selenium (Se), antimony (Sb), copper (Cu) and nickel (Ni). Thus, the regulatory ''drivers'' for toxic metals in contaminated soils/groundwaters are very comparable for Federal and civilian industrial sites, and most sites have more than one metal above regulatory action limits. Thus improving the performance of remedial technologies for metal-contaminated groundwater will have ''dual use'' (Federal and civilian) benefit
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Bioluminescence monitor and method for enzymatic determinations. [Patents]
An on-line, nonreferenced apparatus for measuring the concentration of a biomarker species in authentic biological samples in solution comprises conduit means for conducting said sample solution from a source of said solution, stream diversion means disposed within the conduit for diverting a predetermined amount of said sample for analysis, means for introducing and independently regulating the flow of one or more reactants disposed in fluid communication with said diverted stream, incubating means within the diverted stream for reacting said reactants and biomarkers to produce a bioluminescence emission, and means disposed within the diverted stream for monitoring said emission intensity which is correlatable to said biomarker concentration