达氏鲟精子的主要生物学特性

达氏鲟(Acipenser dabryanus)属淡水定居性鲟鱼类,为我国特有种,主要分布在长江上游干流及金沙江下游。长期人为过度捕捞及其生存环境的持续污染和水利工程的影响,使得达氏鲟自然种群资源遭到严重破坏,其配子质量的下降己经成为限制其规模化人工繁殖成功的关键因素之一,因此为解决达氏鲟规模化人工繁殖过程中存在的关键性技术点,作者从达氏鲟精液基本特征、精浆元素组成以及不同水体和Na+、K+对达氏鲟精子活力的影响、精子超微结构方面入手,对达氏鲟精子的生理生态特性进行了研究。结果显示,达氏鲟精子平均密度为1.52×109个/ml;精浆元素以Na+含量最高,其次是K+,之后为Ca2+、Mg2+、Cu2+、Zn2+,其中Na+、K+、Zn2+在达氏鲟精浆中的含量有极显著性差异(P0.01),Ca2+、Cu2+、Mg2+差异不明显;精子在江水中的活力最高;在Na+浓度为20 mmol/L时,精子活力最高,精子快速运动时间(FT)和寿命(LT)分别为(66.7±7.1)s和(177.0±14.9)s;达氏鲟精子对K+浓度变化较为敏感,在K+浓度为0.05 mmol/L时,精子FT和LT最长,分别为(109.0±16.1)s和(189.3±12.4)s,K+浓度超过0.05 mmol/L后精子FT和LT急速下降,当K+浓度达到0.5 mmol/L以上时,精子活力立即受到抑制;达氏鲟精子细胞核长(5.67±0.20)μm,鞭毛长(63.16±2.79)μm,全长为(70.35±2.92)μm。     

Na+、葡萄糖、果糖对凹目白鲑精子活力的影响

研究了凹目白鲑（Coregonus autumnalis）精子在302．6～488．9kPa时的NaCl溶液、D-葡萄糖溶液及D-果糖溶液中的活动情况。结果显示,在NaCl溶液中凹目白鲑精子在395．7kPa具最佳活力,其快速运动时间（fast movement time,FT）与寿命时间（1ife time,LT）的最大值分别达43．57s和90．31s;与相同渗透压下NaCl溶液相比,凹目白鲑精子在葡萄糖和果糖溶液中的FT与LT均有不同程度的增加;在葡萄糖溶液中FT与LT的最大值分别为57．67s和97．29s,在果糖溶液中则为70．44s和105．29s。说明凹目白鲑精子活力不但与溶液渗透压有关,而且与溶液溶质有关。     

Na+、K+、Mg2+、Ca2+和葡萄糖溶液作为授精-激活介质对中华鲟精子受精率的影响

以不同浓度的NaCl、KCl、MgCl2、CaCl2溶液和葡萄糖溶液作为授精介质,研究了中华鲟(Acipenser sinensis)的受精效果.结果显示,适量的阳离子和葡萄糖作为激活授精介质时中华鲟卵受精率都有所提高.在实验设置浓度范围内25 mmol/L NaCI溶液、0.1 mmol/L KCl溶液、1 mmol/L MgCl2溶液、1 mmol/LCaCh溶液和50 mmol/L葡萄糖溶液浓度下,受精率分别可达到最高值,依次为87.72%、86.82%、82.24%、89.76%、80.92%.随着实验浓度继续增加,受精率反而呈下降趋势.结果显示,作为人工配制的中华鲟精子授精一激活介质,最适NaCI溶液浓度在25 mmol/L附近,最适葡萄糖溶液浓度在25 mmol/L附近,最适KCI溶液浓度≤0.1 mmol/L,最适MgCl2溶液浓度≤1 mol/L,最适CaCh溶液浓度≤1 mmol/L.     

环境因子对眼斑拟石首鱼精子活力的影响

通过测定精子的激活率、运动时间及寿命,研究了pH、盐度、离子及葡萄糖等因子变化对眼斑拟石首鱼(Csiaenops ocellatus)精子活力的影响.结果表明,眼斑拟石首鱼精液中精子平均浓度为(1.203±0.22)×10~(10)个·mL~(-1);精子激活与运动的适宜盐度范围为20～35,其中盐度25时精子的激活率、运动时间及寿命分别达94.32%、9.14min及12.55min;精子激活与运动的适宜pH为6.0～8.5,适宜的KCl、NaCl及CaCl_2溶液浓度分别为600～700 mmol·L~(-1)、600mmol·L~(-1)及400～600 mmol·L~(-1),适宜的葡萄糖溶液浓度为700～900mmol·L~(-1);精子在缺少HCO_3~-或Mg~(2+)或Ca~(2+)的人工海水中激活率与在人工海水中的激活率无显著差异,但运动时间和寿命有所缩短.     

鮸鱼精子的生理特性及超低温冻存

通过测定精子的激活率、运动时间及寿命,研究了鮸鱼精子的生理特性,以0.5mL麦细管为冻存管、两步降温法超低温冻存鮸鱼精子。结果表明,鮸鱼精子激活与运动的适宜盐度为20~30、适宜pH值为5.5~9.0,适宜的KCl、NaCl、CaCl2溶液浓度分别为（500~600）mmol/L、（400~500）mmol/L、（300~400）mmol/L,适宜的葡萄糖溶液浓度为（800~900）mmol/L。无Ca2＋、Mg2＋及HCO3-的人工海水均能使鮸鱼精子激活,但运动时间及寿命有所下降。以Cortland溶液为稀释液,10%Gly、15%Gly、5%DMSO、10%DMSO、15%DMSO、10%EG、10%PG、15%PG及20%PG为抗冻剂,超低温冻存鮸鱼精子15d后,冻精的活力与鲜精相比无显著差异,其中,以10%Gly为抗冻剂冻存精子的效果最好,冻精的激活率、运动时间及寿命分别达（86.38±1.63）%、（8.24±1.37）min及（10.21±0.42）min。     

环境因子及超低温冻存对黄姑鱼精子活力的影响

通过测定精子的激活率、运动时间及寿命研究了环境因子变化对黄姑鱼精子活力的影响及超低温冻存后黄姑鱼精子的活力。结果表明,黄姑鱼精子激活与运动的适宜盐度为25～35、适宜pH为7.5～8.5。在pH 8.0～8.5、盐度25条件下,精子激活率达(85.33±2.52)%,运动时间及寿命分别为(336±14.02)s及(405.33±12.22)s。精子激活与运动的适宜NaCl、KCl、MgCl₂及葡萄糖溶液浓度分别为300～500 mmol·L^-1、600 mmol·L^-1、800～1000 mmol·L^-1及900mmol·L^-1;精子在缺少HCO₃^-的人工海水中未能被激活;精子在无Ca²⁺或无Mg²⁺的人工海水中激活率均大于80%,但运动时间及寿命均有所缩短。以Cortland及HBSS溶液为稀释液、10%EG为抗冻剂冻存黄姑鱼精子,冻精激活率>80%,运动时间均超过200s。     

钠、钾、钙和葡萄糖对白斑狗鱼精子活力的影响

观察了白斑狗鱼精子在0～679．6kPa NaCl、KCl、葡萄糖溶液和0～339．8kPa CaCl2溶液中的活动情况。在NaCl、KCl、葡萄糖溶液中,白斑狗鱼精子快速运动时间和寿命的变化规律基本一致,精子活动最适渗透压介于339．8～453．0kPa。K^ 有延长精子寿命的作用。外源性葡萄糖可被精子利用,增强精子活力．延长精子寿命。56．7kPa CaCl2对精子活动有抑制作用,并引起精子聚集,该效应随着Ca^2 浓度升高而增强。     

盐胁迫对四季竹细胞膜透性和矿质离子吸收、运输和分配的影响

采用盆栽控制试验,研究了土壤不同NaCl浓度(0(CK)、1‰、2‰、3‰、4‰、5‰和6‰)处理45 d对四季竹叶片脱落率和细胞膜透性以及立竹器官K+、Na+、Ca2+和Cl-等矿质离子的吸收、运输和分配的影响.结果表明,1‰～2‰NaCl处理对四季竹叶片脱落率和离子渗漏率无显著影响,3‰～6‰ NaCl处理显著提高了叶片脱落率和离子渗漏率,四季竹的盐胁迫伤害随土壤盐浓度的增大而加剧.随着Na+、Cl-在四季竹立竹各器官中的显著增加,竹根、竹秆、竹枝K+含量逐渐下降,Ca2+含量变化较小,并且K+、Ca2+在竹根、竹秆中的向上选择性运输能力逐渐减弱.由于竹叶在低浓度(1‰～2‰)和高浓度(3‰～6‰)盐胁迫下分别对Ca2+和K+具有较高的选择性吸收能力,随盐浓度的增大,竹叶K+含量迅速升高,Ca2+含量先升高后下降,这对维持竹叶的营养平衡和正常生长具有重要意义.3‰～6‰NaCl处理时,Na+、Cl-在竹叶中的浓度显著高于立竹其他器官,不仅降低了竹叶的渗透势,有利于水分的向上运输,而且四季竹还可以通过叶片脱落的方式降低体内的盐分含量,减轻盐离子毒害.     

金属离子对蜡蚧菌几丁质酶活力的影响

以蜡蚧菌(Ll)发酵液为材料,经分离纯化获得Ll几丁质酶(EC3.2.1.14)制剂.研究了金属离子对Ll几丁质酶活力的影响.结果表明,K+、Mg2+、Zn2+、Ca2+和Fe3+对几丁质酶活性有明显的促进作用,而Na+和Cu2+完全抑制几丁质酶的活性;Mn2+在低浓度时对酶有激活作用,随着浓度的升高表现出抑制作用;Fe2+和Ba2+的浓度低于0.5 mmol/L时对酶起抑制作用,而高于该浓度时则对酶有激活作用.     

水体中铜对中华鲟幼鱼血液生化指标的影响

通过检测中华鲟在不同铜离子浓度的水体中暴露60d后血液生化指标,研究Cu2+对幼鱼血浆生化成分和离子含量变化的影响及致毒效应.结果表明:中华鲟幼鱼血浆中血糖( Glu)、碱性磷酸酶(ALP)、尿素(Urea)、胆固醇(TC)、肌酐(CREA)含量随Cu2+浓度的增加而升高,低浓度组(0.40 μg· L-1)ALP含量与对照组有显著性差异(P＜0.05),Glu、Urea、TC、CREA含量无显著性差异;中浓度组(0.89 μg· L-1)和高浓度组(2.00 μg·L-1)含量与对照组均有显著性差异(P＜0.05).甘油三酯(TG)随着Cu2+浓度的增加而下降,低浓度组与对照组无显著性差异;中、高浓度组与对照组有显著差异(P＜0.05),总蛋白(TP)、谷草转氨酶(AST)、谷丙转氨酶(ALT)、乳酸脱氢酶(LDH-L)不受Cu2+的影响.Na+、Cl-、P含量和pH值随Cu2+浓度的增加而显著下降,Ca2+、Mg2+显著上升,其变化与Cu2+浓度存在相关性,K+含量不受Cu2+的影响.实验表明,Cu2+对中华鲟幼鱼血液生化指标的最低可观察效应浓度和最高无观察效应浓度分别为0.89和0.4 μg·L-1.血浆中ALP受Cu2+影响最明显,其含量除受Cu2+浓度影响外,随着时间的延长也显著升高,是Cu2+污染的敏感指标.     

EEG Activity in the Process of Measuring-off of Time Intervals by Humans

We recorded EEG from sites C3 and C4 in an experimental situation with internal counting-off of a 20-sec-long time interval, whose beginning and end were limited by the tested subject by pushing a button; 65 adult men and women took part in the tests. In the first experimental series, the subject obtained no real information on the accuracy in production of the interval. In the second series, such information was displayed by feedback visual signals. We calculated means of the measured intervals ( ), coefficient of variation of the realizations (CV), and, in the series with the real feedback, successfulness of measuring-off (normalized number of fits within an acceptable range of the standard interval, 19 to 21 sec). Analysis of the data obtained in the first experimental series for the entire tested group demonstrated the existence of a reverse dependence between the modal frequency of EEG beta rhythm recorded from the left hemisphere in the course of measuring-off of the interval and the value. In the second series, we found significant negative correlation between the beta rhythm power in both hemispheres and CV, that between the alpha rhythm power in the left hemisphere and , and positive correlation between the alpha rhythm frequency in the left hemisphere and successfulness of the interval counting-off. Analysis of the dynamics of EEG of each tested subject demonstrated the existence of mostly reverse dependences between the powers of a few EEG rhythms and duration of the produced interval. We hypothesize that the frequencies of the alpha and beta EEG oscillations play the role of significant indices reflecting the speed of the internal clock of the individual. We also emphasize the complex nature and the high individual variability of the EEG pattern in the course of measuring-off of time intervals.     

Does gantry rotation time influence accuracy of volume computed tomography dose index (CTDIvol) in modern CT?

PurposeThe purpose of this study was to develop a gantry overrun corrected CTDI_vol (cCTDI_vol) dosimetry and evaluate the differences between the displayed CTDI_vol (dCTDI_vol), measured CTDI_vol (mCTDI_vol), and the cCTDI_vol.Methods and materialsThe each 8 rotation times between 275 and 1000 ms of two CT scanners were investigated. Rotation time (T_rot) and the beam-on time (T_beam) in axial scanning were measured accurately to determine the gantry overrun time (T_over) as T_beam − T_rot. Subsequently, mCTDI_vol was measured by using a 100 mm ionization chamber and CTDI phantoms. Furthermore, we introduced a gantry overrun correction factor (C_o = T_rot/T_beam) to obtain cCTDI_vol. Upon completion of the data acquisition, the dCTDI_vol and mCTDI_vol were compared with the cCTDI_vol.ResultsThe discrepancies of T_rot were 0.2 ± 0.2 ms as compared to the preset rotation times, and T_over was machine-specific and almost constant (22.4 ± 0.5 ms or 45.1 ± 0.3 ms) irrespective of the preset rotation time. Both dCTDI_vol and mCTDI_vol were increasingly overestimated compared to cCTDI_vol as the faster the preset rotation time was selected (1.7–23.5%).ConclusionThe rotation time influences the accuracy of CTDI_vol in modern CT, and should be taken into consideration when assessing the radiation output in modern CT.     

The Analysis of the Geometric Structure of the Delayed Time Used in the Embedding Process in Predicting Chaotic Time Series

1IntroductionForaphysicssyStem,onemayonlyobtainapieceOfiofo~ionabbotitSd~edPaces.In~cases,oneorat~SeveralvariableSoftheSyStemismeaSUledasthesyStemevolvesinaclodoftime.ExamplesarethemeaSuredtetnperatUle,blabsP~ofahumanthey;concentrationsof~entsinachendcalreaction,componentsofthevelvetyOfthefluidincertaindirectionSandthefluctuationOfthePriceinasacmarket.AllthesemeasureddatapresentasatIme~esxl,xZ,'.,xj,inwhichthesuhiindexpreSentSthetimeSampledregUlarlybyatimenitedr.Thequestionhereishow…     

Prospects for the biology of human intelligence

Despite the ubiquitous nature of Spearman's g in mental test performance, the charge «intelligence is what intelligence tests test» has not been countered in a satisfactory way. It is proposed that there are two ways to answer this complaint. The first concerns the new hypothesis testing models in factor analysis. The second involves studying the ‘biology of intelligence’. The biology of intelligence has various meanings and four are discussed: biology as theory; biology as race and genetics; biology as neurobiology; and biology as basic psychological processes. The last of these is considered in some detail and it is found that reaction time, evoked potentials and inspection time offer bright prospects for further research on the biology of psychometric intelligence.     

A three‐component system incorporating Ppd‐D1, copy number variation at Ppd‐B1, and numerous small‐effect quantitative trait loci facilitates adaptation of heading time in winter wheat cultivars of worldwide origin

The broad adaptability of heading time has contributed to the global success of wheat in a diverse array of climatic conditions. Here, we investigated the genetic architecture underlying heading time in a large panel of 1,110 winter wheat cultivars of worldwide origin. Genome‐wide association mapping, in combination with the analysis of major phenology loci, revealed a three‐component system that facilitates the adaptation of heading time in winter wheat. The photoperiod sensitivity locus Ppd‐D1 was found to account for almost half of the genotypic variance in this panel and can advance or delay heading by many days. In addition, copy number variation at Ppd‐B1 was the second most important source of variation in heading, explaining 8.3% of the genotypic variance. Results from association mapping and genomic prediction indicated that the remaining variation is attributed to numerous small‐effect quantitative trait loci that facilitate fine‐tuning of heading to the local climatic conditions. Collectively, our results underpin the importance of the two Ppd‐1 loci for the adaptation of heading time in winter wheat and illustrate how the three components have been exploited for wheat breeding globally.     

Consequences of sexually dimorphic timing of emergence and flowering in Silene latifolia

1 Males and females of dioecious plant species often differ in a variety of secondary characteristics, such as size, flower number and flowering time, suggesting that dioecious species have sex-specific selection histories. However, a potential source of these dimorphic traits is age differences between males and females. By sowing 3000 seeds of the dioecious perennial, Silene latifolia (Caryophyllaceae), on a single day, we were able to assess the contribution of sex differences in emergence time to the development of sexually dimorphic adult traits.
2 Females emerged before males in our experimental field population, but on average males flowered first. Age differences between males and females did not therefore cause the earlier flowering of males.
3 The consequence of the detected differences in emergence and phenology between males and females was explored by path analysis. Emergence time had a strong direct effect on flower production as well as an indirect effect through flowering time. The regression coefficient of flowering time on emergence time was significantly larger for male plants.
4 A phenotypic selection analysis revealed that seedlings emerging early suffered greater mortality than those emerging later. Seedlings emerging early, however, developed into plants with more flowers, indicating that there was a trade-off between survivorship and reproductive performance. Seeds with intermediate emergence times had the highest total fitness, indicating the presence of stabilizing selection. Despite the strong mortality selection against early emergers, we detected no shift in the sex ratio compared with the sex ratio of seeds matured under low-mortality greenhouse conditions.     

Disorders of the Menstrual Cycle in Elite Female Ice Hockey Players and Figure Skaters

The purpose of this study was to assess and compare the incidence of delayed menarche and menstrual dysfunction among elite ice hockey players and figure skaters. Forty-three ice hockey players (23.5 ± 4.8 years, 68.2 ± 1.2 kg, 1.68 ± 0.01 m) and 39 figure skaters (17.5 ± 3.4 years, 53.7 ± 5.8 kg, 1.64 ± 0.05 m) completed a self-administered questionnaire on their menstrual status and history, training regimens and lifestyle. Age at menarche did not differ significantly between ice hockey players (13.3 ± 1.3 years) and figure skaters (13.7 ± 1.4 years). Menarche was unrelated to nationality, vigorous training premenarche or age at which the athlete began her sport, but was correlated with the age at menarche of the athletes’ mothers (r = 0.39, p < 0.05). Hormonal contraceptives were used by 35% of ice hockey players and 15% of the figure skaters. Amenorrhea and oligomenorrhea were experienced by 7.1% and 38.7% of postmenarcheal, ice hockey players and figure skaters respectively not using hormonal contraceptives. Menstrual dysfunction was associated with both age and age at menarche in the ice hockey players only. Training factors, and psychological pressure were perceived by the athletes to contribute to menstrual dysfunction. A greater training volume, younger age at commencing sport, lower body mass, greater subjective body image pressure and younger biological and gynaecological age were reported among the figure skaters, and were proposed to explain the higher incidence of menstrual dysfunction among the figure skaters compared with the ice hockey players. Figure skaters appear at increased risk of amenorrhea and oligomenorrhea compared with ice hockey players, which may be linked to training and physical characteristics of the sports.     

立止血对家兔止血效果的研究

目的 观察立止血对家兔的止血效果,为该药的临床应用及研究类似产品提供可借鉴的资料。方法 测定家兔静注立止血前、后的因时间和凝血时间值,经统计学分析。结果 静沪立止血后所测不同时估（测至２４ｈ）的出血时间、凝血时间均经注药前自身空白对照缩短,具阶段性。结论 初步证实立止血具有高效、速效、长效、安全的作用特性,同时揭示立止血的止血功能具阶段性的特点。