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Duncan Earle 《American anthropologist》1995,97(4):791-794
Book reviewed in this article:
Massacres in the Jungle; Ixcan, Guatemala 1975–1982 . Ricardo Falla. 相似文献
Massacres in the Jungle; Ixcan, Guatemala 1975–1982 . Ricardo Falla. 相似文献
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SANDY SMITH-NONINI 《American anthropologist》2006,108(1):225-228
Legalizing Moves: Salvadoran Immigrants' Struggle for U.S. Residency . Susan Bibler Coutin. Ann Arbor: University of Michigan Press, 2003. 228 pp.
The Maya of Morganton: Work and Community in the Nuevo New South . Leon Fink. Chapel Hill: University of North Carolina Press, 2003. 254 pp.
The Children of NAFTA: Labor Wars on the U.S./Mexico Border . David Bacon. Berkeley: University of California Press, 2004. 348 pp. 相似文献
The Maya of Morganton: Work and Community in the Nuevo New South . Leon Fink. Chapel Hill: University of North Carolina Press, 2003. 254 pp.
The Children of NAFTA: Labor Wars on the U.S./Mexico Border . David Bacon. Berkeley: University of California Press, 2004. 348 pp. 相似文献
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《Journal of biological education》2012,46(1):41-45
The mathematics in school biology is investigated by means of an analysis of the questions in examination papers set over a period of time in biological subjects by the University of London Examinations Board. Throughout, the incidence of questions requiring mathematics changes but remains low, while the range of mathematics topics called upon remains both restricted and unchanging. However, the various biological examination subjects differ markedly with respect both to the changes in the incidence of such questions and to the range and frequency with which the topics are used. Certain difficulties associated with the mathematics of school biology are identified, and biology teachers are encouraged to discuss these with their colleagues who teach mathematics. 相似文献
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Over the past several years, RNAi and its related phenomena have emerged not only as a powerful experimental tool but also as a new mode of gene regulation. Through a combination of genetic and biochemical approaches we have learned much about the mechanisms underlying dsRNA responses. However, many of the most intriguing aspects of dsRNA-induced gene silencing have yet to be illuminated. What has become abundantly clear is that the complex and highly conserved biology underlying RNA interference is critical both for genome maintenance and for the development of complex organisms. However, it seems probable that we have only begun to reveal the diversity of biological roles played by RNAi-related processes. 相似文献
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C Godber 《BMJ (Clinical research ed.)》1984,288(6429):1473-1474
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Cardiac atrophy after bed rest and spaceflight. 总被引:7,自引:0,他引:7
M A Perhonen F Franco L D Lane J C Buckey C G Blomqvist J E Zerwekh R M Peshock P T Weatherall B D Levine 《Journal of applied physiology》2001,91(2):645-653
Cardiac muscle adapts well to changes in loading conditions. For example, left ventricular (LV) hypertrophy may be induced physiologically (via exercise training) or pathologically (via hypertension or valvular heart disease). If hypertension is treated, LV hypertrophy regresses, suggesting a sensitivity to LV work. However, whether physical inactivity in nonathletic populations causes adaptive changes in LV mass or even frank atrophy is not clear. We exposed previously sedentary men to 6 (n = 5) and 12 (n = 3) wk of horizontal bed rest. LV and right ventricular (RV) mass and end-diastolic volume were measured using cine magnetic resonance imaging (MRI) at 2, 6, and 12 wk of bed rest; five healthy men were also studied before and after at least 6 wk of routine daily activities as controls. In addition, four astronauts were exposed to the complete elimination of hydrostatic gradients during a spaceflight of 10 days. During bed rest, LV mass decreased by 8.0 +/- 2.2% (P = 0.005) after 6 wk with an additional atrophy of 7.6 +/- 2.3% in the subjects who remained in bed for 12 wk; there was no change in LV mass for the control subjects (153.0 +/- 12.2 vs. 153.4 +/- 12.1 g, P = 0.81). Mean wall thickness decreased (4 +/- 2.5%, P = 0.01) after 6 wk of bed rest associated with the decrease in LV mass, suggesting a physiological remodeling with respect to altered load. LV end-diastolic volume decreased by 14 +/- 1.7% (P = 0.002) after 2 wk of bed rest and changed minimally thereafter. After 6 wk of bed rest, RV free wall mass decreased by 10 +/- 2.7% (P = 0.06) and RV end-diastolic volume by 16 +/- 7.9% (P = 0.06). After spaceflight, LV mass decreased by 12 +/- 6.9% (P = 0.07). In conclusion, cardiac atrophy occurs during prolonged (6 wk) horizontal bed rest and may also occur after short-term spaceflight. We suggest that cardiac atrophy is due to a physiological adaptation to reduced myocardial load and work in real or simulated microgravity and demonstrates the plasticity of cardiac muscle under different loading conditions. 相似文献
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M Erik Huso Jeffrey S Hampl Carol S Johnston Pamela D Swan 《Journal of applied physiology》2002,93(6):2018-2022
The influence of creatine supplementation on substrate utilization during rest was investigated using a double-blind crossover design. Ten active men participated in 12 wk of weight training and were given creatine and placebo (20 g/day for 4 days, then 2 g/day for 17 days) in two trials separated by a 4-wk washout. Body composition, substrate utilization, and strength were assessed after weeks 2, 5, 9, and 12. Maximal isometric contraction [1 repetition maximum (RM)] leg press increased significantly (P < 0.05) after both treatments, but 1-RM bench press was increased (33 +/- 8 kg, P < 0.05) only after creatine. Total body mass increased (1.6 +/- 0.5 kg, P < 0.05) after creatine but not after placebo. Significant (P < 0.05) increases in fat-free mass were found after creatine and placebo supplementation (1.9 +/- 0.8 and 2.2 +/- 0.7 kg, respectively). Fat mass did not change significantly with creatine but decreased after the placebo trial (-2.4 +/- 0.8 kg, P < 0.05). Carbohydrate oxidation was increased by creatine (8.9 +/- 4.0%, P < 0.05), whereas there was a trend for increased respiratory exchange ratio after creatine supplementation (0.03 +/- 0.01, P = 0.07). Changes in substrate oxidation may influence the inhibition of fat mass loss associated with creatine after weight training. 相似文献
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Todd A Dorfman Benjamin D Levine Tommy Tillery Ronald M Peshock Jeff L Hastings Suzanne M Schneider Brandon R Macias Gianni Biolo Alan R Hargens 《Journal of applied physiology》2007,103(1):8-16
Both chronic microgravity exposure and long-duration bed rest induce cardiac atrophy, which leads to reduced standing stroke volume and orthostatic intolerance. However, despite the fact that women appear to be more susceptible to postspaceflight presyncope and orthostatic hypotension than male astronauts, most previous high-resolution studies of cardiac morphology following microgravity have been performed only in men. Because female athletes have less physiological hypertrophy than male athletes, we reasoned that they also might have altered physiological cardiac atrophy after bed rest. Magnetic resonance imaging was performed in 24 healthy young women (32.1 +/- 4 yr) to measure left ventricular (LV) and right ventricular (RV) mass, volumes, and morphology accurately before and after 60 days of 6 degrees head-down tilt (HDT) bed rest. Subjects were matched and then randomly assigned to sedentary bed rest (controls, n = 8) or two treatment groups consisting of 1) exercise training using supine treadmill running within lower body negative pressure plus resistive training (n = 8), or 2) protein (0.45 g x kg(-1) x day(-1) increase) plus branched-chain amino acid (BCAA) (7.2 g/day) supplementation (n = 8). After sedentary bed rest without nutritional supplementation, there were significant reductions in LV (96 +/- 26 to 77 +/- 25 ml; P = 0.03) and RV volumes (104 +/- 33 to 86 +/- 25 ml; P = 0.02), LV (2.2 +/- 0.2 to 2.0 +/- 0.2 g/kg; P = 0.003) and RV masses (0.8 +/- 0.1 to 0.6 +/- 0.1 g/kg; P < 0.001), and the length of the major axis of the LV (90 +/- 6 to 84 +/- 7 mm. P < 0.001), similar to what has been observed previously in men (8.0%; Perhonen MA, Franco F, Lane LD, Buckey JC, Blomqvist Zerwekh JE, Peshock RM, Weatherall PT, Levine BD. J Appl Physiol 91: 645-653, 2001). In contrast, there were no significant reductions in LV or RV volumes in the exercise-trained group, and the length of the major axis was preserved. Moreover, there were significant increases in LV (1.9 +/- 0.4 to 2.3 +/- 0.3 g/kg; P < 0.001) and RV masses (0.7 +/- 0.1 to 0.8 +/- 0.2 g/kg; P = 0.002), as well as mean wall thickness (9 +/- 2 to 11 +/- 1 mm; P = 0.02). The interaction between sedentary and exercise LV and RV masses was highly significant (P < 0.0001). Protein and BCAA supplementation led to an intermediate phenotype with no change in LV or RV mass after bed rest, but there remained a significant reduction in LV volume (103 +/- 14 to 80 +/- 16 ml; P = 0.02) and major-axis length (91 +/- 5 to 88 +/- 7 mm; P = 0.003). All subjects lost an equivalent amount of body mass (3.4 +/- 0.2 kg control; 3.1 +/- 0.04 kg exercise; 2.8 +/- 0.1 kg protein). Cardiac atrophy occurs in women similar to men following sedentary 60 days HDT bed rest. However, exercise training and, to a lesser extent, protein supplementation may be potential countermeasures to the cardiac atrophy associated with chronic unloading conditions such as in spaceflight and prolonged bed rest. 相似文献
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Theresa A Burnett Eric A Mann Sonia A Cornell Christy L Ludlow 《Journal of applied physiology》2003,94(1):128-134
During swallowing, airway protection is achieved in part by laryngeal elevation. Although multiple muscles are normally active during laryngeal elevation, neuromuscular stimulation of select muscles was evaluated to determine which single muscle or muscle pair best elevates the larynx and should be considered during future studies of neuromuscular stimulation in dysphagic patients. Hooked-wire monopolar electrodes were inserted into mylohyoid, thyrohyoid, and geniohyoid muscle regions in 15 healthy men selected for having a highly visible thyroid prominence for videotaping. During trials of single, bilateral, and combined muscle stimulations, thyroid prominence movements were video recorded, digitized, and normalized relative to elevation during a 2-ml water swallow. Individual muscle stimulation induced approximately 30% of the elevation observed during a swallow and approximately 50% of swallow velocity, whereas paired muscle stimulation resulted in approximately 50% of the elevation and approximately 80% of the velocity produced during a swallow. Paired muscle stimulation produced significantly greater elevation than single muscle stimulation and could assist with laryngeal elevation in dysphagic patients with reduced or delayed laryngeal elevation. 相似文献
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M. Raw 《BMJ (Clinical research ed.)》1989,298(6685):1410
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Arora-Jonsson Seema Pierce Colfer Carol J. González-Hidalgo Marien 《Human ecology: an interdisciplinary journal》2021,49(3):297-308
Human Ecology - We address two aspects of forest lives—violence and care—that are central to forest outcomes but often invisible in mainstream discussions on forests. We argue that... 相似文献
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K Andrews 《BMJ (Clinical research ed.)》1984,288(6429):1518-1520
Sixteen private rest homes were visited to assess their facilities and the types of disability of the residents. Apart from one home, which was a hotel for the elderly, all the homes provided care for physically and mentally frail elderly people over the long term. Although care was good the trends in the use of the homes are worrying, and stricter regulations are required to ensure appropriate levels of care. Greater support is also required from district nursing services. 相似文献