全球健康领域政府对非政府组织的定位与合作——以世卫组织、美国和英国为例

非政府组织(NGO)在全球健康治理中发挥重要角色,已成为欧美发达国家和联合国系统全球健康战略的重要组成部分,联合国可持续发展目标也提出要强化NGO作为全球健康治理合作者的角色。本研究以全球健康战略比较成熟的世界卫生组织和美英两国为例,综述它们在全球健康战略中对NGO的定位和合作,为中国全球健康战略的制定以及与NGO的合作及定位提供参考建议。研究发现,世界卫生组织、美国和英国在其全球健康战略中均给予NGO明确定位,即加强相互合作,来扩大其在全球健康领域的影响力。因此,中国应将NGO纳入全球健康战略,建立NGO的管理和合作机制,使其成为全球健康的重要补充力量;严格筛选国际NGO进行合作,努力培育和支持本土NGO参与中国全球健康项目的实施;制定NGO合作清单和负面清单;同时加强监管和审核,规避NGO可能带来的风险。     

涤纶三维卷曲中空纤维结构性能研究 Ⅰ.涤纶中空纤维在纺丝及后加工过程中结构变化特征

用ＦＲＳ－ＸＲＳＡ、ＳＡＸＳ、ＤＳＣ表征了涤纶中空纤维在整个纺丝及后加工过程中结构的变化特征。结果表明，涤纶中空初生纤维基本是非晶态，在后加工过程中分两步结晶：拉伸应变诱导结晶和热结晶，在一次应变诱导结晶的同时伴随着纤维自卷形成三维卷曲，二次热结晶后形成长周期，使结构得以稳定。     

Length and width summation in human vision at different background levels

Summary The effect of background intensity on the spatial summation of rectangular stimuli of varying length and width was studied in human psychophysical experiments and compared with the known effects of light adaptation on the spatial summation of circular stimuli. Both the detection threshold and the threshold of orientation identification were measured. In agreement with previous data, summation was more efficient along the line stimulus than across it. This asymmetry was found to exist at all adaptation levels studied (1–1000 trolands). The adaptation level affected both length and width summation; the change in the length of summation was twice as great as the change in the diameter of summation with circular stimuli. Orientation selectivity was reduced for short lines presented on a dim background. The results suggest the existence of mechanisms of light adaptation at the level of cortical orientation-selective units.     

Dynamic differentiation of GABAA-sensitive influences on orientation selectivity of complex cells in the cat striate cortex

The influence of GABA_A receptors on orientation selectivity of cat complex cells was tested by iontophoresis of the GABA_A receptor blockers bicuculline and N-methyl-bicuculline while stimulating with drifting sinusoidal gratings. Reduction of orientation tuning was markedly less than reported in previous studies that used drifting bars as visual stimuli. Only 3/31 cells lost orientation selectivity, with an average increase in bandwidth of 33%, as opposed to half the cells losing selectivity and a bandwidth increase for the remainder of 47% as reported previously. Infusion of GABA_A blockers revealed a prominent stimulus onset transient response, lasting about 120 ms, that showed a broadening of orientation selectivity comparable to that found using drifting bars under similar circumstances. We believe that drifting gratings emphasize a steady-state response component that retains, in the presence of GABA_A blockers, significant orientation selectivity. Because the onset transient is initially unselective for orientation, we suggest that the steady-state, orientation-selective response component develops from an alternate inhibitory mechanism, possibly mediated by GABA_B receptors.     

14C-Deoxyglucose mapping of orientation subunits in the cats visual cortical areas

Summary The orientation domain in the cortical visual areas of anesthetized cats has been investigated by employing the ¹⁴C-Deoxyglucose technique (Sokoloff et al., 1977).Orientation subunits (OS) are seen in the first (V1), the second (V2) and the third visual area (V3) as well as in the visual areas of the suprasylvian sulcus. In the latter regions OS are less elaborated than in V1, V2, and V3. The OS are continuous through all cortical layers; in V1 however, only weak label is detected in layer 4C. In V1, V2, and V3 the width of the OS is about 0.4 mm and the average distance between two OS centers is 0.9 mm. The spatial pattern of the OS seems to be more regular in the visual field periphery than in regions representing the vertical meridian.     

Contrast detection and direction discrimination of drifting gratings

Observers performed simple detection and left right discrimination of drifting sinusoidal gratings. Ratio of detection to discrimination sensitivities was measured under variations in several experimental parameters. In the first experiment, it was found that combinations of spatial and temporal frequency which resulted in the same velocity produced similar detection discrimination ratios. At an exposure duration of 800 msec, the relationship between the ratio and velocity described a power function with the intercept at 0.6 sec^?1. Decreasing duration shifted the curve to higher velocities. I examined the effect of grating orientation in a second experiment. Visual sensitivity was poorer for oblique than for vertical gratings with detection and discrimination exhibiting similar size anisotropies. In a third experiment, observers viewed gratings presented to different retinal loci, Visual performance in both detection and discrimination fell with greater eccentricity. However, motion discrimination fell more steeply resulting in an increase in the ratio. The results demonstrate that form and motion analyzing mechanisms cannot be distinguished by their response to changes of spatial frequency, orientation or retinal locus.     

On the efficient two-dimensional energy coding characteristics of spatial vision

Recent evidence indicates that the vertebrate visual system possesses units whose receptive fields may be represented as narrow-band orientation and frequency specific filters. It has been indirectly demonstrated that equivalent psychophysical units act in such a way as to not discriminate the individual frequency components within each frequency band. Here we directly demonstrate this to be the case with digital images and so show an efficient energy code for spatial vision.     

Orientation deprivation in cat: What produces the abnormal cells?

Summary When an animal is reared with goggles containing stripes of a single orientation, many cells in the visual cortex become abnormal. To find out whether these abnormal cells result from orientation deprivation per se or from other features of goggle rearing we reared kittens with goggles containing stripes of many orientations. The data suggest that orientation deprivation contributes to the development of abnormal cells but is not its sole cause.This work was supported by grant EY00125 from the National Eye Institute. Joelle Presson was supported by the Systems Physiology Training grant 5T326M07257     

强磁场对红细胞流变性的影响

用１．０５Ｔ恒定磁场照射兔血３０－１２０分钟后，用激光衍射仪测量红细胞的取向指数，并测量红细胞电泳。结果表明经磁场照射处理后，红细胞的取向指数明显减小，同时电泳时间增加。这表明磁场对静止的红细胞膜发生作用，使其表面电荷减少。     

A functional analysis of the collicular output pathways: a dissociation of deficits following lesions of the dorsal tegmental decussation and the ipsilateral collicular efferent bundle in the Mongolian gerbil

Summary Mongolian gerbils received either lesions of the superior colliculus, small lesions of the uncrossed efferents of the superior colliculus, knifecuts of the dorsal tegmental decussation, or sham operations. The animals were subsequently tested for avoidance of overhead visual threat, orientation and locomotion toward small targets, and negotiation of a large barrier in order to reach a small target. Animals with collicular lesions showed no responses to overhead threat and had severe deficits in orienting to small targets. Animals with lesions of the uncrossed tectal efferents showed diminished responses to overhead threat but had no deficits in orienting to targets. Animals with lesions of the dorsal tegmental decussation showed only slight reductions in responses to overhead threats but clear impairments in the orientation tasks. The impairments in orientation, however, were less severe than those seen in collicular animals. Animals in all groups were able to negotiate barriers efficiently. These results suggest that separate output pathways of the superior colliculus mediate different types of visuomotor behaviours. The results further suggest that visual orientation to small targets does not depend completely on output through the predorsal bundle, but must also involve other collicular outputs.