太湖典型草、藻型湖区紫外辐射的衰减及影响因素分析

2004年4月通过野外原位观测和实验室测定相结合的方法对东太湖和梅梁湾典型草、藻型湖区紫外辐射光谱衰减及影响因素进行了研究。结果表明,320nm(UV-B)、380nm(UV-A)的衰减系数在6.33~19.59m-1、3.41~13.64m-1间变化,对应的1%表面光强穿透深度分别为0.24~0.73m、0.35~1.35m,到达湖面的99%UV-B辐射在0.5m左右表层水就衰减完毕,东太湖和梅梁湾紫外辐射衰减系数存在明显的湖区差异;溶解性有机碳(DOC)的浓度在6.60~17.17mg/L间变化,其均值为(9.99±2.48)mg/L;375nm波长处CDOM吸收系数为1.78~6.25m-1,均值为(3.70±1.10)m-1;在短波部分CDOM吸收与DOC浓度存在显著性相关,相关性大致随波长降低而增加,320nm处的线性关系式:ad320=0.885DOC 2.182;紫外辐射衰减主要受制于水体中的CDOM浓度,衰减系数与DOC浓度、CDOM吸收系数存在显著性相关,340nm处的关系式分别为:Kd340=0.82 1.05DOC、Kd340=1.98 1.49ad340。在太湖紫外辐射衰减还要受悬浮物和叶绿素a浓度的影响,衰减系数与DOC、叶绿素a和悬浮物浓度多元回归的结果明显要高于单独与DOC浓度或CDOM吸收系数的回归结果。     

太湖春季水体固有光学特性及其对遥感反射率变化的影响

吸收特性和后向散射特性是水体重要的光学特性,同时也是建立生物光学模型的基本参数。利用2009年4月太湖春季实测数据,结合生物光学模型推导了太湖春季水体颗粒物后向散射系数,在此基础上分析了太湖春季水体的吸收特性和后向散射特性,并利用经验正交分解方法对遥感反射率变化的影响因子进行了分析。结果表明：（1）非色素颗粒物是影响太湖春季水体吸收特性的主导因子,色素颗粒物和CDOM对总吸收（不包含纯水）的贡献相对较小,且色素颗粒物在梅梁湾湖区的包裹效应明显大于其他湖区。（2）颗粒物后向散射系数与总悬浮物和无机悬浮物具有很强的相关性（相关系数均在0.88以上）,与有机悬浮物的相关性相对较弱（相关系数均在0.73以下）,且水体中多次散射对水面总辐亮度有较大的贡献,平均贡献率高达93.46%。（3）利用经验正交分解方法将遥感反射率变化光谱分解成3个正交因子,3个正交因子总共解释了约99%的遥感反射率变化信息,其中,第一正交因子解释了93%的变化信息,第二和第三正交因子分别解释了5%和1%的变化信息。通过对各正交因子与水体不同组分的吸收和后向散射系数进行相关性分析得出,颗粒物的后向散射对水面反射光谱的形成具有非常重要的影响,太湖春季水体遥感反射率的变化主要取决于无机颗粒物的吸收和后向散射,有机颗粒物对遥感反射率的变化影响较小。     

内陆湖泊水体固有光学特性的典型季节差异

固有光学特性是水体光学性质的重要内容,是水色反演分析模型建立的基础.本研究利用定量滤膜技术（QFT）和后向散射测量仪BB9,对太湖梅梁湾夏、冬季水体的有色可溶性有机物(CDOM)吸收系数、总悬浮物吸收系数和总悬浮物后向散射系数进行了观测.在分别对两季节水体组分吸收系数、后向散射系数光谱特征分析的基础上,阐明其季节差异性,并结合水质参数的变化,揭示导致两季节水体固有光学特性不同的原因,达到通过固有光学量反映水环境状态的目的.初步建立了后向散射系数与悬浮物浓度的关系模型,为分析模型的构建提供了参数保障.     

太湖梅梁湾夏季水体组分光谱吸收特性

2006年8月16、17日对太湖梅梁湾湖区15个样点水体进行采样,利用分光光度计和定量滤膜技术测量了水体要素CDOM、非藻类颗粒物和浮游植物的吸收系数,同时进行水质参数的测定,分别对各水体要素的光谱吸收特性进行分析,并结合水质参数建立相应的区域模式.其中,分UV-C(250～290nm)、UV-B (290～320nm)、UV-A(320～400nm)和蓝光(400～500nm)4个波段建立CDOM光谱吸收的关系模式,同时发现曲线斜率值S与440nm处吸收系数存在很好的二次函数关系,在紫外和蓝光波段R2分别达到0.958和0.835;总悬浮物的光谱吸收特征在不同深度处有些相近,有些则存在明显差异,主要是由有机和无机颗粒物剖面分布的不确定性和总悬浮物浓度所引起;非藻类颗粒物吸收系数在400～700nm的指数函数拟合斜率值S的变化范围为0.0056～0.0090nm-1(平均值(0.0070±0.0008)nm-1),各样点指数函数拟合的R2在0.91以上.在可见光波段范围各水体要素对总吸收系数的贡献大小顺序是:浮游植物＞非藻类颗粒物＞CDOM.浮游植物在蓝、绿和红光波段的平均贡献率都在0.5以上,是水体吸收的主要贡献者;在蓝、绿和红光波段,非藻类颗粒物的平均贡献率分别为0.350±0.145、0.412±0.162和0.232±0.125,CDOM的分别为0.121±0.052、0.088±0.059和0.050±0.038.     

太湖梅梁湾水体悬浮颗粒物和CDOM的吸收特性

通过测定滤膜上悬浮颗粒物和过滤液中CDOM吸光度的方法计算得到太湖梅梁湾总颗粒物和CDOM的光谱吸收系数,并计算了各吸收组份的贡献份额以及吸收与PAR衰减的比值。总颗粒物的吸收系数从400 nm到600 nm大致呈下降趋势,到675nm附近由于叶绿素a的特征吸收会出现明显峰值,峰值高低随叶绿素a浓度的变化而变化,ap(440)在3.58~9.86 m-1间变化。非藻类颗粒物和CDOM的吸收随波长增加大致按指数规律下降,ad(440)和ag(440)的变化范围分别为2.23~7.07m-1和1.06~1.70 m-1。非藻类颗粒物在400~700 nm波段的指数函数斜率Sd的平均值为(10.91±0.62)μm-1;CDOM在280~500 nm波段指数函数斜率Sg的平均值为(15.52±0.49)μm-1。浮游藻类的光谱吸收表现为在440、675 nm附近存在两个明显的峰值,分别为(2.55±1.14)、(1.34±0.69)m-1。ap(440)与TSS、OSSI、SS均存在显著性正相关,而ad(440)则只与TSSI、SS有显著性相关,aph(440)只与OSS、Chla有显著性相关。CDOM吸收系数与DOC浓度没有显著正相关,但与Chla存在显著幂函数关系,浮游藻类降解产物是水体中CDOM的重要来源之一。水体中物质吸收主要以颗粒物为主,对总吸收的贡献率在70%以上,而颗粒物中又以非藻类颗粒物占主导,一般超过40%,总吸收对漫射衰减的贡献也在40%以上。     

东辽河流域河湖光学吸收特性的季节变化

吸收特性是水体重要的光学特性,也是建立水色反演分析模型的基本参数.本文利用2011年6、9、10月在二龙湖和2012年10月在东辽河的实测数据,通过测定水体营养水平和颗粒物、有色可溶性有机物(CDOM)等光学活性物质的吸收系数,分析了东辽河河湖的光学物质吸收特性和季节变化.结果表明: 二龙湖水体9月处于富营养状态,6月营养水平较低,10月则处于中营养水平;东辽河随采样点位置的差异呈现不同程度的富营养化.水体各组分的吸收系数均随营养水平的增加而逐渐增大.6、10月二龙湖水体总悬浮颗粒物吸收光谱与非色素颗粒物吸收光谱相似,在总吸收中占主导作用的是CDOM;9月总悬浮颗粒物吸收光谱则与浮游植物吸收光谱类似,浮游植物的吸收对总吸收的贡献率最大.6、9月二龙湖浮游植物吸收系数[a_ph(440)]与总磷(TP)呈正相关,6月二龙湖a_ph(440)与溶解有机碳(DOC)呈正相关,非藻类颗粒物吸收系数[a_d(440)]仅与叶绿素a浓度(Chl a)具有相关性.二龙湖(9月)与东辽河a_ph(675)均与Chl a、卡尔森指数(TLI)相关性较好.东辽河流域的河湖水体光学特性存在比较明显的差异:东辽河水体的浮游植物吸收光谱曲线展现出了两种不同类型,浮游植物、非藻类颗粒物、CDOM的贡献率随采样点的不同而相差较大;营养水平较高的9月二龙湖与东辽河水体浮游植物主导了水体光谱吸收,而在二龙湖营养水平较低的月份中(6、10月),颗粒物与CDOM共同主导水体光谱吸收;6月二龙湖与10月东辽河水体CDOM的组成为大分子颗粒物,而9与10月其组成更趋向于小分子颗粒物.     

基于VGPM模型和MODIS数据估算梅梁湾浮游植物初级生产力

基于MODIS影像数据反演的2009年2月份至12月份太湖梅梁湾水域表面叶绿素a、悬浮物浓度以及水温数据,结合初级生产力垂向归纳模型(Vertically Generalized Production Model:VGPM)估算获得梅梁湾2009年逐月平均日初级生产力时空分布。结果表明,梅梁湾2009年年平均日初级生产力及逐月平均日初级生产力空间分布差异显著,呈现从湾内向湾口逐渐递减的趋势。时间序列分析显示,梅梁湾初级生产力季节差异显著,夏季>秋季>春季>冬季,全年初级生产力主要集中在夏季,占47.4%。通过分析VGPM模型中几个输入参数对初级生产力的影响,发现悬浮物浓度与标准化初级生产力存在显著负冥函数关系,反映沉积物再悬浮引起的悬浮物浓度增加能降低水体初级生产力。温度对初级生产力也有一定的调控与制约,与初级生产力呈现正相关趋势,在低于21℃的温度范围内与最大光合作用速率呈现正相关。     

辽河水体光学吸收特性的季节变化

吸收特性是水体重要的光学特性,也是建立生物光学模型的基本参数。利用2013年5月和9月辽河流域水体实测数据对总悬浮颗粒物、浮游植物、非藻类颗粒物以及有色溶解有机物(CDOM)的吸收特性、季节变化进行了研究。研究表明,总颗粒物的吸收光谱曲线与非藻类颗粒物的吸收光谱基本保持一致并且与非藻类颗粒物的吸收[a_d(λ)]以及浮游植物的吸收[a_(ph)(λ)]都呈现显著相关。两个季节,a_d(440)均是总吸收的主要组成部分,CDOM的吸收[a_(CDOM)(440)]则大于a_(ph)(440)的贡献率,但9月a_d(440)的吸收所占比例较5月高。辽河水体非藻类颗粒物中矿物颗粒物的含量较其他一般水体要高。通过分析5月及9月的aph(440)/a_(ph)(675)发现浮游植物中辅助色素与叶绿素a浓度(Chla)的组成季节性变化不大,但其空间特征表现较为明显。另外,CDOM的吸收特性与非藻类颗粒物的吸收相似,呈现出较大的空间差异性;辽河S_(CDOM)基本小于其它河流、湖泊、河口等水体,其CDOM主要由大分子物质组成。     

海南新村湾海草床生态系统有色溶解有机物的分布、来源及光降解特性

有色溶解有机物(CDOM)是海洋溶解有机碳(DOC)的重要组成成分,其光降解能加速海草床生源物质和能量的流动。本文以海南新村湾海草床CDOM为研究对象,研究CDOM的空间分布特征,分析其主要来源,并结合光降解实验,探讨CDOM在紫外光(UV-B)照射下内部物质组分的变化过程。结果表明:新村湾冬季CDOM的分布主要表现为海草区最高,河口区域和网箱养殖区次之,而海湾中心最低;海草区和河口区CDOM的类蛋白质与类腐殖质荧光强度比网箱养殖区高;海草区和河流区域的CDOM分子量较大,而网箱养殖区的CDOM分子量较小;CDOM在UV-B下暴露5 d,海草区域、河口区域和网箱养殖区的类蛋白质荧光强度分别下降了44.67%、31.75%和37.09%,表明海草区域类蛋白质吸收了大部分UV-B,降解速率比其他区域快;而类腐殖质荧光强度的下降比例分别为43.64%、36.32%和50.18%,网箱养殖区CDOM的类腐殖质下降速率较快,这可能是由于网箱养殖区的CDOM分子量小,结构简单,易在UV-B照射下降解。因此,海草床海草的释放、河流的输入及网箱养殖区浮游植物的降解是新村湾的CDOM主要来源。     

内陆湖泊主要藻种散射特性

通过室内培养4种主要淡水藻种--铜绿微囊藻(Microcystis aeruginosa)、普通小球藻(Chlorella vulgaris)、梅尼小环藻(Cyclotella meneghiniana)以及卵形隐藻(Cryptomonas ovata), 测定其散射和后向散射特征参数、用单位叶绿素a浓度的散射值和后向散射值来表征4种藻的散射和后向散射能力。结果表明, 铜绿微囊藻散射和后向散射能力最强, 其次为梅尼小环藻, 普通小球藻的能力最弱。通过计算后向散射概率, 显示铜绿微囊藻和梅尼小环藻的后向散射概率值较高, 普通小球藻和卵形隐藻的后向散射概率值较低。后向散射特性影响因子分析显示, 影响后向散射值的主要因素有叶绿素a浓度及藻蓝蛋白色素比例。当叶绿素a浓度不断增加时, 其后向散射值不断增大; 当藻类所含叶绿素a比重不断上升时, 其后向散射值也不断增大。而细胞粒径与后向散射值之间未表现出很好的相关性。因此, 通过单位叶绿素a散射和后向散射概率特征可以辨别出藻细胞形态较为接近的铜绿微囊藻和普通小球藻。     

Substitution determination of Fmoc‐substituted resins at different wavelengths

In solid‐phase peptide synthesis, the nominal batch size is calculated using the starting resin substitution and the mass of the starting resin. The starting resin substitution constitutes the basis for the calculation of a whole set of important process parameters, such as the number of amino acid derivative equivalents. For Fmoc‐substituted resins, substitution determination is often performed by suspending the Fmoc‐protected starting resin in 20% (v/v) piperidine in DMF to generate the dibenzofulvene–piperidine adduct that is quantified by ultraviolet–visible spectroscopy. The spectrometric measurement is performed at the maximum absorption wavelength of the dibenzofulvene–piperidine adduct, that is, at 301.0 nm. The recorded absorption value, the resin weight and the volume are entered into an equation derived from Lambert–Beer's law, together with the substance‐specific molar absorption coefficient at 301.0 nm, in order to calculate the nominal substitution. To our knowledge, molar absorption coefficients between 7100 l mol^?1 cm^?1 and 8100 l mol^?1 cm^?1 have been reported for the dibenzofulvene–piperidine adduct at 301.0 nm. Depending on the applied value, the nominal batch size may differ up to 14%. In this publication, a determination of the molar absorption coefficients at 301.0 and 289.8 nm is reported. Furthermore, proof is given that by measuring the absorption at 289.8 nm the impact of wavelength accuracy is reduced. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.     

Chromophoric dissolved organic matter (CDOM) absorption characteristics in relation to fluorescence in Lake Taihu,China, a large shallow subtropical lake

Absorption measurements from chromophoric dissolved organic matter (CDOM) and their relationships with dissolved organic carbon (DOC) and fluorescence were studied in Lake Taihu, a large, shallow, subtropical lake in China. Absorption spectra of lake water samples were measured from 240 nm to 800 nm. Highest values of a(λ), DOC and F _n (355) occurred near the river inflow to Meiliang Bay and decreased towards the central lake basin. A significant spatial difference was found between Meiliang Bay and the central lake basin in absorption coefficient, DOC-specific absorption coefficient, exponential slope coefficient, DOC concentration and fluorescence value. The spatial distribution of CDOM suggested that a major part of CDOM in the lake was from river input. CDOM absorption coefficients were correlated with DOC over the wavelength range 280–500 nm, and a(355) was also correlated with F _n (355), which showed that CDOM absorption could be inferred from DOC and fluorescence measurement. The coefficient of variation between a(λ) and DOC concentration decreased with increase in wavelength from 240 nm to 800 nm. Furthermore, a significant negative linear relationship was recorded between S value and CDOM absorption coefficient, as well as DOC-specific absorption coefficient. S value and DOC-specific absorption coefficient were used as a proxy for CDOM composition and source. Accurate CDOM absorption measurements are very useful in explaining UV attenuation and in developing, validating remote sensing model of water quality in Lake Taihu.     

Ion competition effects on the selective absorption of radionuclides by komatsuna (Brassica rapa var. perviridis)

The selective absorption coefficient, which is a parameter of an uptake model of radionuclides by plants, was determined for various radionuclides by a multitracer technique. Komatsuna, Brassica rapa var. perviridis, was hydroponically cultivated in a nutrient solution containing a multitracer for 1 day. Nutrient concentration dependence of the selective absorption coefficient of various elements from Be to Re was obtained separately for leaves and roots. The selective absorption coefficients of these elements were, in general, found to decrease with an increase in the concentration of nutrient solutions. Regression equations of the power function for the selective absorption coefficients and the concentration of nutrient solutions were obtained for the leaves and roots. The effects of photon flux and growth stage of plants on the selective absorption coefficients were also studied. It was found that the photon flux influenced the accumulation of radionuclides in the roots but had no significant effect on the selective absorption coefficients for the leaves in 1-day cultivation with the multitracer. The selective absorption coefficients of Mn and Zn in the leaves of the plants at the development stage were higher than those at the maturation stage. For the other elements, no significant effects of the growth stage on the selective absorption coefficients were observed.     

用组织光学特性鉴别诊断人离体的正常膀胱和膀胱癌组织

研究正常人膀胱和膀胱癌组织在Kube lka-Munk二流模型下对476.5 nm,514.5 nm和808 nm波长的激光的光学特性的差异。采用双积分球系统和Kube lka-Munk二流模型进行测量研究。实验结果表明,正常膀胱和膀胱癌组织在Kube lka-Munk二流模型下对476.5 nm,514.5 nm和808 nm波长的每一个波长的激光的吸收、散射、总衰减、有效衰减系数都有非常显著性的差异(P<0.01)。膀胱癌组织对476.5 nm,514.5 nm和808nm波长的激光的吸收系数明显地较正常膀胱组织对相应波长的激光的吸收系数要大(P<0.01),膀胱癌组织对476.5 nm和514.5 nm波长的激光的散射系数明显地较正常膀胱组织对相应波长的激光的散射系数要小(P<0.01),而膀胱癌组织对808 nm波长的激光的散射系数明显地较正常膀胱组织对同一波长的激光的散射系数要大(P<0.01)。膀胱癌组织对476.5 nm,514.5 nm和808 nm波长的激光的总衰减系数明显地较正常膀胱组织对相应波长的激光的总衰减系数要大(P<0.01),膀胱癌组织对476.5 nm,514.5 nm和808 nm波长的激光的有效衰减系数明显地较正常膀胱组织对相应波长的激光的有效衰减系数要大(P<0.01)。提示使用双积分球系统和Kube lka-Munk二流模型来确定离体的正常膀胱组织和膀胱癌组织对476.5 nm,514.5 nm和808nm波长的激光的光学特性的差异鉴别诊断病变的膀胱组织是一个有效的方法。     

采用不同的光传输模型比较研究结肠的散射和吸收特性:离体结肠肿瘤的光学诊断

测定和比较研究了离体的正常的和腺癌的人结肠粘膜/粘膜下层以及正常的和腺癌的人结肠肌层/浆膜组织对630 nm,680 nm,720 nm,780 nm,810 nm,850 nm和890 nm波长的钛宝石激光的散射和吸收系数。采用双积分球测量系统测量组织样品对七个不同波长的激光的准直透射、漫反射和漫透射,从实验所测结果以及分别采用反向倍增法和反演蒙特卡罗技术这两个光学模型计算出组织的散射和吸收系数。研究结果表明,无论是用反向倍增法还是用反演蒙特卡罗法,每一种类型的正常的和腺癌的人结肠组织对同一波长的激光的吸收系数和散射系数有显著性的差异(P<0.01),正常的和腺癌的结肠组织的散射和吸收系数有大的差异,这些结果提示每种类型的正常和腺癌的结肠组织的组份和结构之间有大的差异。四种类型的结肠组织对七个不同波长的激光的散射系数较其吸收系数至少要大三个数量级,而四种类型的结肠组织对七个不同波长的激光的散射系数有相同的数量级。     

Identity of the subunits and the stoicheiometry of prosthetic groups in trimethylamine dehydrogenase and dimethylamine dehydrogenase.

Trimethylamine dehydrogenases from bacterium W3A1 and Hyphomicrobium X and the dimethylamine dehydrogenase from Hyphomicrobium X were found to contain only one kind of subunit. The millimolar absorption coefficient of a single [4Fe-4S] cluster in trimethylamine dehydrogenase from bacterium W3A1 was estimated to be 14.8 mM-1 . cm-1 at 443 nm. From this value a 1:1 stoicheiometry of the prosthetic groups, 6-S-cysteinyl-FMN and the [4Fe-4S] cluster, was established. Millimolar absorption coefficients of the three enzymes were in the range 49.4-58.7 mM-1 . cm-1 at approx. 440 nm. This range of values is consistent with the presence of two [4Fe-4S] clusters and two flavin residues, for which the millimolar absorption coefficient had earlier been found to be 12.3 mM-1 . cm-1 at 437 nm. The N-terminal amino acid was alanine in each of the three enzymes. Sequence analysis of the first 15 residues from the N-terminus of dimethylamine dehydrogenase indicated a single unique sequence. Two identical subunits, each containing covalently bound 6-S-cysteinyl-FMN and a [4Fe-4S] cluster, in each of the enzymes are therefore indicated.     

Optical characteristics of the phototroph Thiocapsa roseopersicina and implications for real-time monitoring of the bacteriochlorophyll concentration.

Optical characteristics of a Thiocapsa roseopersicina culture and environmental samples containing T. roseopersicina were investigated in the spectral range of 400 to 1,100 nm (absorption coefficient, diffuse attenuation coefficient, and reflectance). Specific absorption coefficients of T. roseopersicina at wavelengths of 480, 520, 550, 580, 805, 860, and 880 nm were determined. It is suggested that the optical properties of T. roseopersicina in the near-infrared range of 800 to 930 nm, confirmed in this study, may be used for development of remote sensing techniques for real-time monitoring of T. roseopersicina and other bacteriochlorophyll a-containing microbes.     

Molecular extinction coefficients of lead sulfide and polymerized diaminobenzidine as final reaction products of histochemical phosphatase reactions.

Molar extinction coefficients of precipitated lead sulfide (PbS) and polymerized diaminobenzidine (polyDAB) have been determined at wavelengths of 450 nm and 480 nm, respectively, for quantitative histochemical analysis of phosphatase reactions. These values are essential for the conversion of cytophotometric (mean integrated) absorbance values to absolute units of substrate converted per unit time and volume of tissue. This conversion allows direct comparison of histochemical and biochemical data. The molar extinction coefficient of PbS at 450 nm was found to be 3,800 and therefore, per mole phosphate liberated, the molar extinction coefficient is 5,700 because 3 moles phosphate are captured by 2 moles lead at neutral or alkaline pH. Parallel experiments with the cerium-DAB method revealed that the molar extinction coefficient of polyDAB at 480 nm is 5,500 with respect to liberated phosphate. The molar extinction coefficients were applied for comparison of data from biochemical and histochemical assays of glucose-6-phosphatase activity in rat livers. A significant correlation was found between both sets of data. The values were in the same order of magnitude with histochemical values approximately 1.4 times higher than biochemical values.     

Effects of Manipulations with Visual Feedback on Postural Responses in Humans Maintaining an Upright Stance

We studied postural reactions evoked by vibrational stimulation of the anterior tibial and posterior neck muscles under three different conditions of visual control (in a darkened room): (i) upon standing with the eyes open, EO, with perception of a stationary 2D image of the visual environment on the screen, (ii) under conditions of perception of a 3D virtual visual environment, VVE, and (iii) upon standing with the eyes closed, EC. Vibrational stimulation of both muscle groups evoked forward inclinations of the body; average values of the latter under control conditions (EC) were close to each other. The VVE mimicking a real visual environment possessed two planes, a mobile foreground one, whose shifts were programmed in such a manner that they correlated with oscillations of the body, and a stable background one. The tested subjects were asked to use the latter as a visual reference. Under VVE conditions, the amplitude of postural reactions depended on the feedback coefficient between the body movements and shifts of the VVE foreground and the direction of this feedback (its synphase or antiphase, sph or aph, mode). Postural responses at the feedback sph direction became greater with increase in the feedback coefficient (i.e., with increases in the magnitude of shifts of the VVE foreground) and reached values typical of standing under EC conditions. In the case of the aph type of feedback, the responses changed insignificantly. If the lowest feedback coefficient, 1.0, was used, the postural responses tended to decrease, as compared with those under EO conditions. The difference between the values observed at the sph and aph types of feedback with similar coefficients was manifested more intensely in the case of stimulation of the neck muscles. This fact shows that postural reactions triggered by afferent signals from the neck muscles depend more considerably on the ongoing visual afferentation.