Suppression of herbivory by macroalgal density: a critical feedback on coral reefs?

Coral reefs globally are in decline, with some reefs undergoing phase shifts from coral-dominance to degraded states dominated by large fleshy macroalgae. These shifts have been underpinned by the overharvesting of herbivorous fishes and represent a fundamental change in the physical structure of these reefs. Although the physical structure provided by corals is regarded as a key feature that facilitates herbivore activity, the influence of the physical structure of macroalgal stands is largely unknown. Using transplanted Sargassum, the largest coral reef macroalga, we created habitat patches of predetermined macroalgal density (0.25-6.23 kg m(-2)). Remote video cameras revealed both grazing and browsing fishes avoided high density patches, preferring relatively open areas with low macroalgal cover. This behaviour may provide a positive feedback leading to the growth and persistence of macroalgal stands; increasing the stability of phase shifts to macroalgae.     

不同心理素质水平军人在厌恶情绪条件下自主神经反应特点

目的：探讨不同心理素质水平军人在厌恶情绪条件下自主神经反应特点。方法：用军人心理素质量表筛选出54名部队官兵,其中高、中、低心理素质组军人各18名。采用3份情绪视频材料,诱导被试的中性和厌恶情绪,利用八通道多参数生物反馈仪,记录自主神经反应的十个指标和相应自主神经反应指标的平均恢复时间。结果：（1）在中性情绪条件下,低心理素质组[（12．06±4．89）b／min]的心率（HR）的变化上显著大于高心理素质组[（5．75±2．80）b／min];（2）在厌恶情绪条件下,低心理素质组f（7．09±2．02）nU]的心率变异性（rmv）频谱归-化低频功率（Lfnorm）的变化显著大于中等[（3．43±1．70）nU]与高心理素质组[（2．66±1．50）nU];低心理素质组[（357．94±129．33）Hz]的总功率（TP）的变化显著大于中等[（171．1±73．02）ms。]与高心理素质组[（167．84±86．38）ms／];（3）在自主神经反应指标的恢复时间上,低心理素质组[（49．98±10．96）秒]在厌恶情绪条件下其心率（HR）的恢复时间显著大于高心理素质组[（24．65±9．38）see];低心理素质组[（37．84±21．33）sec]在厌恶情绪条件下其皮电（SC）、皮温（TEMP）、指端血容振幅（BVP）、心率（HR）四个自主神经反应指标的平均恢复时间上显著大于高心理素质组[（18．57±10．15）秒]。（4）在情绪的愉悦度、唤醒度的上,低心理素质组（0．88±1．11）在中性条件下其唤醒度的变化明显大于中等（0．50±0．70）与高心理素质组（0．12±0．33）;低心理素质组（-2．11±0．90）在厌恶条件下愉悦度的变化明显大于中等（-1．56±0．86）与高心理素质组（-1．33±0．84）。结论：在中性条件下,低心理素质军人更容易出现生理上的唤醒警觉状态。在厌恶情绪条件下,低心理素质军人是副交感神经伴有较强交感神经兴奋的自主神经反应模式;高、中等心理素质军人副交感神经伴有较弱的交感神经兴奋。     

陆军青年军人心理素质与人格、心理健康的相关研究

目的：探讨陆军青年军人心理素质与人格、心理健康的关系。方法：整群抽取陆军青年官兵881名,采用军人心理素质量袁、艾森克人格问卷（EPQ）、症状自评量表（SCL-90）进行测评,进行方差分析和相关分析。结果：（1）陆军青年军人心理素质各因子分及总分与EPQ人格问卷中的E分呈显著正相关（p〈0．01）;与N分、P分呈显著负相关（p〈0．01）。高、中、低心理素质水平军人E、P、N得分比较有显著差异（p〈0．05）,表现为在E量表得分上高心理素质组〉中等心理素质组〉低心理素质组;而在P、N量表得分上则反之。（2）陆军青年军人心理素质各因子分及总分均与SCL-90各因子分和总均分呈显著负相关（p〈0．01）。高、中、低心理素质水平军人SCL-90各因子得分比较有显著差异（p〈0．05）,表现为低心理素质组〉中等心理素质组〉高心理素质组。结论：陆军青年军人心理素质与心理健康密切相关,心理素质越高,其心理健康水平也越高。     

低压舱模拟飞行对于脑力负荷影响的初步探讨

目的：通过低压舱模拟飞行环境下被试人员生理指标的变化,探讨飞行员脑力负荷的变化规律。方法：21名男性志愿者参加低压舱模拟飞行的实验过程,座舱内的压力高度模拟2400米高空压力,持续时间1．5h,重复两次,中间出舱休息0．5h,检测指标为心率变异性（HRV）,心理运动测验以及NASA—TLX主观评定量表。结果：研究表明,NASA－TLX量表从主观感受上很好的反映了低压舱模拟飞行后脑力负荷的变化,HRV、心理运动测验也发生了相应的变化。结论：本研究结果提示低压舱模拟飞行所导致的脑力负荷变化是具有一定规律的,生理心理测验可能是测定变化规律的一种间接方法。     

不同心理素质水平军人在厌恶情绪条件下自主神经反应特点

目的:探讨不同心理素质水平军人在厌恶情绪条件下自主神经反应特点。方法:用军人心理素质量表筛选出54名部队官兵,其中高、中、低心理素质组军人各18名。采用3份情绪视频材料,诱导被试的中性和厌恶情绪,利用八通道多参数生物反馈仪,记录自主神经反应的十个指标和相应自主神经反应指标的平均恢复时间。结果:(1)在中性情绪条件下,低心理素质组[(12.06±4.89)b/min]的心率(HR)的变化上显著大于高心理素质组[(5.75±2.80)b/min];(2)在厌恶情绪条件下,低心理素质组[(7.09±2.02)nU]的心率变异性(HRV)频谱归一化低频功率(Lfnorm)的变化显著大于中等[(3.43±1.70)nU]与高心理素质组([2.66±1.50)nU];低心理素质组([357.94±129.33)Hz]的总功率(TP)的变化显著大于中等([171.14±73.02)ms2]与高心理素质组([167.84±86.38)ms2];(3)在自主神经反应指标的恢复时间上,低心理素质组([49.98±10.96)秒]在厌恶情绪条件下其心率(HR)的恢复时间显著大于高心理素质组([24.65±9.38)sec];低心理素质组([37.84±21.33)sec]在厌恶情绪条件下其皮电(SC)、皮温(TEMP)、指端血容振幅(BVP)、心率(HR)四个自主神经反应指标的平均恢复时间上显著大于高心理素质组([18.57±10.15)秒]。(4)在情绪的愉悦度、唤醒度的上,低心理素质组(0.88±1.11)在中性条件下其唤醒度的变化明显大于中等(0.50±0.70)与高心理素质组(0.12±0.33);低心理素质组(-2.11±0.90)在厌恶条件下愉悦度的变化明显大于中等(-1.56±0.86)与高心理素质组(-1.33±0.84)。结论:在中性条件下,低心理素质军人更容易出现生理上的唤醒警觉状态。在厌恶情绪条件下,低心理素质军人是副交感神经伴有较强交感神经兴奋的自主神经反应模式;高、中等心理素质军人副交感神经伴有较弱的交感神经兴奋。     

Mental health system in China: history, recent service reform and future challenges

This paper summarizes the history of the development of Chinese mental health system; the current situation in the mental health field that China has to face in its effort to reform the system, including mental health burden, workforce and resources, as well as structural issues; the process of national mental health service reform, including how it was included into the national public health program, how it began as a training program and then became a treatment and intervention program, its unique training and capacity building model, and its outcomes and impacts; the barriers and challenges of the reform process; future suggestions for policy; and Chinese experiences as response to the international advocacy for the development of mental health.     

KELP PATCH DYNAMICS IN THE FACE OF INTENSE HERBIVORY: STABILITY OF AGARUM CLATHRATUM (PHAEOPHYTA) STANDS AND ASSOCIATED FLORA ON URCHIN BARRENS1

The brown alga Agarum clathratum (Dumortier) is the only large, perennial, fleshy macrophyte commonly found on urchin‐dominated barrens in the northwestern North Atlantic. We examined the spatial and temporal stability of A. clathratum stands and their impact on algal recruitment in the Mingan Islands, northern Gulf of St. Lawrence. The stands were highly stable in space and time, with only small intersite variations. The percent cover of A. clathratum in 144‐m² areas increased by 6.5%–11.4% over a 2‐year period, and most changes in abundance occurred at the edge of the stands. The surface area of small (<13 m²) single stands of A. clathratum increased by approximately 1.8%·month^?1, although marked increases (>95%) occurred during winter, largely because adjacent stands merged into larger single stands. Mature stands of A. clathratum appear to enhance algal recruitment, as juvenile A. clathratum and the understory red alga Ptilota serrata (Kützing) were orders of magnitude more abundant inside than outside the stands. The experimental removal of the A. clathratum canopy (1‐m² portions) had no long‐term effect on the abundance of A. clathratum, which within 14 months had recolonized most of the cleared areas. In contrast to juvenile A. clathratum, the abundance of P. serrata rapidly decreased after canopy removal. Our results demonstrate that A. clathratum stands are a stable component of urchin barrens in spite of the heavy grazing that typically occurs there. Maintenance and expansion of A. clathratum stands and associated flora appear to depend on positive interactions with self‐defended adult A. clathratum.     

Post-fire recovery of Mediterranean ground ant communities follows vegetation and dryness gradients

Aim In the Mediterranean Basin, the main forest communities vary in their ability to recover after fire. In this study we analyse the effects of fire on ant communities occurring in various vegetation types distributed along a geographical gradient in the western Mediterranean region. Location The study was carried out in burned and unburned habitats of 22 sites corresponding to eight vegetation types distributed along a gradient of dryness throughout Catalonia (north‐east Spain). Methods We placed five pairs of plots (one plot located in the burned area and the second one placed in the unburned margin) per site. We compared ant communities in these unburned and burned plot types 8 years after fire using pitfall traps. Traps were set out in mid‐May and mid‐July. We analysed the structure and composition of ant communities in the burned and unburned areas of these vegetation types using anova tests, correspondence analysis (CA) and linear regression. Results The resilience of ant communities varies with vegetation type. Ant communities in forests with high resilience also recover rapidly after fire, while those in forests that do not recover after fire show the lowest resilience. Species richness does not depend on burning or vegetation type. The resilience of these Mediterranean ant communities to fire is related to the environmental characteristics of the region where they live. Accordingly, differences between burned and unburned habitats are smaller for ant communities in areas with higher water deficit in summer than for those in moister ones. Main conclusions The structure and composition of ant communities after fire depends on the level of direct mortality caused by the fire. It affects ant species differently, as determined by the habitats used for nesting and foraging. The reestablishment of vegetation cover depends on forest composition before the fire. As vegetation cover determines resource and microhabitat availability and competitive relationships among species, forest composition before the fire also affects post‐fire recovery of ant communities to the medium‐term. Finally, ant communities living in drier areas recover more quickly after fire than those living in moister ones. This pattern might be because in areas with higher water deficit there are more species characteristic of open environments, which are habitats similar to those generated after fire.     

Endothelin-1 response to mental stress in early ischemic lesions of the extremities due to systemic sclerosis

We studied circulating levels of endothelin-1, catecholamines and nitric oxide after a mental arithmetic test in 14 patients with early ischemic lesions of the extremities due to systemic sclerosis and slightly impaired peripheral vascular flow. The test induced an increase (P < 0.01) in blood pressure, heart rate, endothelin-1 and catecholamine levels, whereas it did not change the low basal levels of nitric oxide. In healthy subjects (n = 20) the test significantly (P < 0.01) decreased endothelin-1 without affecting nitric oxide. The low basal levels of nitric oxide and the high plasma concentration of endothelin-1 after psychological stress cannot be explained by an impaired release from the limited ischemic lesions alone. This suggests a diffuse microvascular derangement that aggravates the course of peripheral microvascular ischemic lesions.