3,303 research outputs found
A Mixed-Method Approach for Quantifying Illegal Fishing and Its Impact on an Endangered Fish Species
No full textIllegal harvest is recognized as a widespread problem in natural resource management. The use of multiple methods for quantifying illegal harvest has been widely recommended yet infrequently applied. We used a mixed-method approach to evaluate the extent, charac- ter, and motivations of illegal gillnet fishing in Lake Hovsgol National Park, Mongolia and its impact on the lake’s fish populations, especially that of the endangered endemic Hovsgol grayling (Thymallus nigrescens). Surveys for derelict fishing gear indicate that gillnet fishing is widespread and increasing and that fishers generally use 3–4 cm mesh gillnet. Interviews with resident herders and park rangers suggest that many residents fish for subsistence during the spring grayling spawning migration and that some residents fish commercially year-round. Interviewed herders and rangers generally agree that fish population sizes are decreasing but are divided on the causes and solutions. Biological monitoring indicates that the gillnet mesh sizes used by fishers efficiently target Hovsgol grayling. Of the five species sampled in the monitoring program, only burbot (Lota lota) showed a significant decrease in population abundance from 2009–2013. However, grayling, burbot, and roach (Rutilus ruti- lus) all showed significant declines in average body size, suggesting a negative fishing impact. Data-poor stock assessment methods suggest that the fishing effort equivalent to each resident family fishing 50-m of gillnet 11–15 nights per year would be sufficient to over- exploit the grayling population. Results from the derelict fishing gear survey and interviews suggest that this level of effort is not implausible. Overall, we demonstrate the ability for a mixed-method approach to effectively describe an illegal fishery and suggest that these methods be used to assess illegal fishing and its impacts in other protected areas.Peer reviewe
Christopher Dawson
No full textInspired with Jude P. Dougherty’s works in which he stresses the overruling importance of the classical, humanistic education and the central place and role of religion in the Western culture, the author presents Christopher Dawson’s analysis of the Western civilization and his demonstration of the central role of Christianity in it. The author traces the premises on which was based Dawson’s opinion that modern Western man might be absorbed by his technical inventions, to the point of losing his soul
sj-png-2-njn-10.1177_20571585241227583 - Supplemental material for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics
No full textSupplemental material, sj-png-2-njn-10.1177_20571585241227583 for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics by Christopher Holmberg in Nordic Journal of Nursing Research</p
sj-png-1-njn-10.1177_20571585241227583 - Supplemental material for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics
No full textSupplemental material, sj-png-1-njn-10.1177_20571585241227583 for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics by Christopher Holmberg in Nordic Journal of Nursing Research</p
sj-png-3-njn-10.1177_20571585241227583 - Supplemental material for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics
No full textSupplemental material, sj-png-3-njn-10.1177_20571585241227583 for Swedish nursing research: A bibliometric and content analysis revealing author and institute collaborations, impact, and topics by Christopher Holmberg in Nordic Journal of Nursing Research</p
Founders: Christopher Taylor
No full text\ua9 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. ‘Founders’ is an intermittent series of short, critical appreciations of scholars, researchers and others whose work and ideas, mainly in Britain, have made particularly sweeping, influential and foundational contributions to the development of historically- and archaeologically-informed landscape studies. This latest addition to the series concerns Christopher Taylor, whose death on 28th May 2021 was noted in the Landscapes editorial in issue 21.2
Chronic High Fructose Intake Reduces Serum 1,25(OH)<sub>2</sub>D<sub>3</sub>Levels in Calcium-Sufficient Rodents
No full textExcessive fructose consumption inhibits adaptive increases in intestinal Ca2+transport in lactating and weanling rats with increased Ca2+requirements by preventing the increase in serum levels of 1,25(OH)2D3. Here we tested the hypothesis that chronic fructose intake decreases 1,25(OH)2D3 levels independent of increases in Ca2+ requirements. Adult mice fed for five wk a high glucose-low Ca2+ diet displayed expected compensatory increases in intestinal and renal Ca2+ transporter expression and activity, in renal CYP27B1 (coding for 1α-hydroxylase) expression as well as in serum 1,25(OH)2D3 levels, compared with mice fed isocaloric glucose- or fructose-normal Ca2+ diets. Replacing glucose with fructose prevented these increases in Ca2+ transporter, CYP27B1, and 1,25(OH)2D3 levels induced by a low Ca2+ diet. In adult mice fed for three mo a normal Ca2+ diet, renal expression of CYP27B1 and of CYP24A1 (24-hydroxylase) decreased and increased, respectively, when the carbohydrate source was fructose instead of glucose or starch. Intestinal and renal Ca2+ transporter activity and expression did not vary with dietary carbohydrate. To determine the time course of fructose effects, a high fructose or glucose diet with normal Ca2+ levels was fed to adult rats for three mo. Serum levels of 1,25(OH)2 D3 decreased and of FGF23 increased significantly over time. Renal expression of CYP27B1 and serum levels of 1,25(OH)2D3 still decreased in fructose- compared to those in glucose-fed rats after three mo. Serum parathyroid hormone, Ca2+ and phosphate levels were normal and independent of dietary sugar as well as time of feeding. Thus, chronically high fructose intakes can decrease serum levels of 1,25(OH)2D3 in adult rodents experiencing no Ca2+ stress and fed sufficient levels of dietary Ca2+. This finding is highly significant because fructose constitutes a substantial portion of the average diet of Americans already deficient in vitamin D.Peer reviewe
Using Contextual Information with Dynamic Linkbases to Provide Adaptive Hypermedia
No full textThis report provides an overview of the work that the author has conducted into the field of adaptive hypermedia systems. This work produced an agent-based adaptive link augmentation system that was presented at the first adaptive hypermedia conference. The knowledge gained from creating this system has been combined with context research to produce a system for augmenting links based on a document’s spatial context. These links are provided from a collection of linkbases, which are activated on demand. Presented with this work is an overview of the history of AH, including a description of some of the pivotal AH, recommender and knowledge delivery systems. The report concludes with the author’s view of the future for this research, including a work plan covering the next 16 months
The resistance of cortical bone tissue to failure under cyclic loading is reduced with alendronate
No full textBisphosphonates are the most prescribed preventative treatment for osteoporosis. However, their long-term use has recently been associated with atypical fractures of cortical bone in patients who present with low-energy induced breaks of unclear pathophysiology. The effects of bisphosphonates on the mechanical properties of cortical bone have been exclusively studied under simple, monotonic, quasi-static loading. This study examined the cyclic fatigue properties of bisphosphonate-treated cortical bone at a level in which tissue damage initiates and is accumulated prior to frank fracture in low-energy situations. Physiologically relevant, dynamic, 4-point bending applied to beams (1.5 mm × 0.5 mm × 10 mm) machined from dog rib (n=12/group) demonstrated mechanical failure and micro-architectural features that were dependent on drug dose (3 groups: 0, 0.2, 1.0mg/kg/day; alendronate [ALN] for 3 years) with cortical bone tissue elastic modulus (initial cycles of loading) reduced by 21% (p<0.001) and fatigue life (number of cycles to failure) reduced in a stress-life approach by greater than 3-fold with ALN1.0 (p<0.05). While not affecting the number of osteons, ALN treatment reduced other features associated with bone remodeling, such as the size of osteons (-14%; ALN1.0: 10.5±1.8, VEH: 12.2±1.6, ×10(3) μm2; p<0.01) and the density of osteocyte lacunae (-20%; ALN1.0: 11.4±3.3, VEH: 14.3±3.6, ×10(2) #/mm2; p<0.05). Furthermore, the osteocyte lacunar density was directly proportional to initial elastic modulus when the groups were pooled (R=0.54, p<0.01). These findings suggest that the structural components normally contributing to healthy cortical bone tissue are altered by high-dose ALN treatment and contribute to reduced mechanical properties under cyclic loading conditions.NOTICE: this is the author's version of a work that was accepted for publication in Bone. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Bone, Volume 64 (July 2014) DOI: 10.1016/j.bone.2014.03.045Peer reviewe
The effects of estrogen deficiency on cortical bone microporosity and mineralization
No full textRecent studies have demonstrated matrix-mineral alterations in bone tissue surrounding osteocytes in estrogen-deficient animals.While cortical bone porosity has been shown to be a contributor to the mechanical properties of bone tissue, little analysis has been done to investigate the effects of estrogen deficiency on bone's microporosities, including the vascular and osteocyte lacunar porosities. In this study we examined alterations in cortical bone microporosity, mineralization, and cancellous bone architecture due to estrogen deficiency in the ovariectomized rat model of postmenopausal osteoporosis. Twenty-week-old female Sprague–Dawley rats were subjected to either ovariectomy or sham surgery. Six weeks post-surgery tibiae were analyzed using high-resolution micro-CT, backscattered electron imaging, nanoindentation, and dynamic histomorphometry. Estrogen deficiency caused an increase in cortical bone vascular porosity, with enlarged vascular pores and little change in tissue mineral density in the proximal tibial metaphysis. Measurements of cancellous architecture corresponded to previous studies reporting a decrease in bone volume fraction, an increase in trabecular separation, and a decrease in trabecular number in the proximal tibia due to estrogen deficiency. Nanoindentation results showed no differences in matrix stiffness in osteocyte-rich areas of the proximal tibia of estrogen-deficient rats, and bone labeling and backscattered electron imaging showed no significant changes in mineralization around the vascular pores. The findings demonstrate local surface alterations of vascular pores due to estrogen deficiency. An increase in cortical vascular porosity may diminish bone strength as well as alter bone mechanotransduction via interstitial fluid flow, both of which could contribute to bone fragility during postmenopausal osteoporosis.Peer reviewe
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