1,847 research outputs found
The release of a captive-raised female African Elephant <em>(Loxodonta africana</em>) in the Okavango Delta, Botswana
Wild female elephants live in close-knit matrilineal groups and housing captive elephants in artificial social groupings can cause significant welfare issues for individuals not accepted by other group members. We document the release of a captive-raised female elephant used in the safari industry because of welfare and management problems. She was fitted with a satellite collar, and spatial and behavioural data were collected over a 17-month period to quantify her interactions with the wild population. She was then monitored infrequently for a further five-and-a-half years. We observed few signs of aggression towards her from the wild elephants with which she socialized. She used an area of comparable size to wild female elephants, and this continued to increase as she explored new areas. Although she did not fully integrate into a wild herd, she had three calves of her own, and formed a social unit with another female and her calf that were later released from the same captive herd. We recommend that release to the wild be considered as a management option for other captive female elephants
The 1856 presidential campaign in Virginia
The purpose of this paper is to examine how the 1856 presidential election campaign was conducted in Virginia. The paper specifically investigates how Virginia newspapers interpreted the events of the campaign. The role played by the political leadership of Virginia in the 1856 election is also examined.
The paper is based on contemporary newspaper editorials and political speeches. The manuscripts of prominent Virginia politicians during the period are also utilized.
The paper illustrates how Democratic newspaper editorials in Virginia used scare tactics to convince readers that Virginia Know-Nothings were abolitionists. Know-Nothing editorials responded by emphasizing support for the Union and repudiating Democratic calls for secession. The paper compares how Democratic and Know-Nothing political leaders in Virginia participated in the 1856 campaign
Weekly Versus Monthly Testosterone Administration On Fast and Slow Skeletal Muscle Fibers in Older Adult Males
Context: In older adults, loss of mobility due to sarcopenia is exacerbated in men with low serum T. T replacement therapy is known to increase muscle mass and strength, but the effect of weekly (WK) vs monthly (MO) administration on specific fiber types is unknown.
Objective: To determine the efficacy of WK vs MO T replacement on the size and functional capacity of individual fast and slow skeletal muscle fiber types.
Design, Setting, and Patients:
Subjects were randomized into a 5-month, double-blind, placebo-controlled trial. All subjects (ages, 61–71 y) were community-dwelling men who had T levels \u3c 500 ng/dL.
Intervention: Subjects were dosed weekly for 5 months, receiving continuous T (WK, n = 5; 100 mg T enanthate, im injection), monthly cycled T (MO, n = 7; alternating months of T and placebo), or placebo (n = 7). Muscle biopsies of the vastus lateralis were obtained before and after treatment.
Main Outcome Measures: Main outcomes for individual slow and fast fibers included fiber diameter, peak force (P0), rate of tension development, maximal shortening velocity, peak power, and Ca2+ sensitivity.
Results: Both treatments increased fiber diameter and peak power, with WK treatment 5-fold more effective than MO in increasing type I fiber P0. WK effects on fiber diameter and force were 1.5-fold higher in slow fibers compared to fast fibers. In fast type II fibers, diameter and P0 increased similarly between treatments. The increased power was entirely due to increased fiber size and force.
Conclusions: In conclusion, T replacement effects were fiber-type dependent, restricted to increases in cell size, P0, and peak power, and dependent on the paradigm selected (WK vs MO)
Understanding soil organic matter change: Modeling root and soil interactions across agricultural landscapes
What are some options for enhancing organic content and carbon storage in soils that have been used in intensive row-crop production? The project looked at bioenergy feedstocks and how they might be employed to improve soil properties
How do marine mammals manage and usually avoid gas emboli formation and gas embolic pathology? critical clues from studies of wild dolphins
© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Fahlman, A., Moore, M. J., & Wells, R. S. How do marine mammals manage and usually avoid gas emboli formation and gas embolic pathology? critical clues from studies of wild dolphins. Frontiers in Marine Science, 8, (2021): 598633, https://doi.org/10.3389/fmars.2021.598633.Decompression theory has been mainly based on studies on terrestrial mammals, and may not translate well to marine mammals. However, evidence that marine mammals experience gas bubbles during diving is growing, causing concern that these bubbles may cause gas emboli pathology (GEP) under unusual circumstances. Marine mammal management, and usual avoidance, of gas emboli and GEP, or the bends, became a topic of intense scientific interest after sonar-exposed, mass-stranded deep-diving whales were observed with gas bubbles. Theoretical models, based on our current understanding of diving physiology in cetaceans, predict that the tissue and blood N2 levels in the bottlenose dolphin (Tursiops truncatus) are at levels that would result in severe DCS symptoms in similar sized terrestrial mammals. However, the dolphins appear to have physiological or behavioral mechanisms to avoid excessive blood N2 levels, or may be more resistant to circulating bubbles through immunological/biochemical adaptations. Studies on behavior, anatomy and physiology of marine mammals have enhanced our understanding of the mechanisms that are thought to prevent excessive uptake of N2. This has led to the selective gas exchange hypothesis, which provides a mechanism how stress-induced behavioral change may cause failure of the normal physiology, which results in excessive uptake of N2, and in extreme cases may cause formation of symptomatic gas emboli. Studies on cardiorespiratory function have been integral to the development of this hypothesis, with work initially being conducted on excised tissues and cadavers, followed by studies on anesthetized animals or trained animals under human care. These studies enabled research on free-ranging common bottlenose dolphins in Sarasota Bay, FL, and off Bermuda, and have included work on the metabolic and cardiorespiratory physiology of both shallow- and deep-diving dolphins and have been integral to better understand how cetaceans can dive to extreme depths, for long durations.Many of the studies that have resulted in the data in this review, and that have been integral to develop the selective gas exchange hypothesis have been funded by the Office of Naval Research (ONR Awards # N000141010159, N000141613088, N000141410563, N000140811220, and ONR YIP Award # N000141410563), and Dolphin Quest. The authors declare that Dolphin Quest was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication
PREDICTORS OF INTERNATIONAL SKI FEDERATION DISTANCE CROSS-COUNTRY RANKING
The Internationl Ski Federation (FIS) ranks Nordic skiers internationally based on race performance. This study aimed to determine if a relationship exists between FIS rankings and performance indicators such as maximum oxygen uptake, metabolic economy, and muscular endurance test performance. Muscular endurance (sit-up + pull-up and push-up + pull-up) were the best predictors utilizing stepwise regression resampling cross-validation (66 hold out groups). The sit-up + pull-up regression was a better fit than the push-up + pull-up (R2 = 0.506 & 0.349, p = 0.053 & 0.203, respectively). Muscular endurance test performance predicts FIS scores better than measures of oxygen consumption measures. Upper-body and core musculature may be an important determinant of performance, as it contributes to generation of propulsive forces in Nordic skiing
Factors Influencing Soil Aggregation and Particulate Organic Matter Responses to Bioenergy Crops across a Topographic Gradient
Bioenergy crops have the potential to enhance soil carbon (C) pools fromincreased aggregation and the physical protection of organicmatter; however, our understanding of the variation in these processes over heterogeneous landscapes is limited. In particular, little is known about the relative importance of soil properties and root characteristics for the physical protection of particulate organic matter (POM). We studied short-term (3-year) changes in aggregation and POM-C pools under three cropping systems (switchgrass, a triticale/sorghumdouble crop, continuous corn) replicated across five landscape positions along a topographic gradient in Iowa, USA.We isolated POMassociated with three aggregate fractions (N2mm, 0.25–2mm, and 0.053–0.25mm) to determine the relative influence of ten soil and three root properties. Aggregation increased in all cropping systems andwas greatest under switchgrass; however cropping systemeffectswere not consistent among positions. Total soil organic C stocks did not change, but Cwithin both physically protected (iPOM-C) and unprotected (frPOM) C pools increased. Shifts in iPOM-C were concurrently influenced by soil properties and root traits. Soil texture had the strongest influence (65% relative importance), with finer-textured soils showing greater gains in total iPOM-C, while greater root biomass influenced (35% relative importance) accrual of total iPOM-C. Aggregate fractions varied in their iPOM-C response to soil and root variables, however individual pools similarly showed the importance of soil texture and root biomass and annual root productivity (BNPP). Changes in frPOM-C were strongly correlated with BNPP. Our data suggest that macroaggregate formation drives short-term responses of POM, which are influenced by both soil and root system properties. Crops that maximize root biomass and BNPP will lead to the largest increases in protected soil C stocks. However, C storage rates will vary across landscapes according to soil conditions, with texture as the primary influence
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