Analysis of early growth of guppy strains,Poecilia reticulata,with different color patterns

Summary The guppy, Poecilia reticulata, is economically the most important species of freshwater ornamental fish cultured in Singapore. About 30 strains with different color patterns and fin shapes are reared in guppy farms practising monoculture in Singapore. To compare the growth rates of domesticated strains with different color patterns, newborn fry of 11 strains were obtained on the same day from a single farm in Singapore and were reared experimentally in the laboratory for about 100 days. Each strain was distributed randomly into 4 tanks with 30 fish/tank. Weekly weighings of 10 fish/tank were made from 17 to 100 days of age. Three strains were homozygous for the autosomal recessive blond gene which gives rise to a pale yellow background pigmentation (bb). These blond strains had significantly smaller body weights than corresponding ones with the same color pattern but with the wild-type grey-brown background coloration due to the dominant allele (BB). The strains with the red tail pattern due to a dominant X-linked gene (Rdt) had more rapid growth than those with other tail color patterns including the blue, black, green snakeskin and variegated. However, no significant differences were detected among the other color pattern strains. Thus among the strains studied, the blond strains were associated with slower growth while those with the red tail color were associated with faster growth.     

Freezing of fresh Barhi dates for quality preservation during frozen storage

Fresh harvested dates are perishable and there is a need for extending their shelf life while preserving their fresh like quality characteristics. This study evaluates three different freezing methods, namely cryogenic freezing (CF) using liquid nitrogen; individual quick freezing (IQF) and conventional slow freezing (CSF) in preserving the quality and stability of dates during frozen storage. Fresh dates were frozen utilizing the three methods. The produced frozen dates were frozen stored for nine months. The color values, textural parameters, and nutrition qualities were measured for fresh dates before freezing and for the frozen dates every three months during the frozen storage. The frozen dates’ color values were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing followed by individual quick freezing compared to the conventional slow freezing. The results revealed large disparity among the times of freezing of the three methods. The freezing time accounted to 10 min for CF, and around 80 min for IQF, and 1800 min for CSF method.     

产前经腹灰阶联合彩色血流超声多参数对胎盘植入性疾病的诊断效能研究

摘要 目的：探究产前经腹灰阶联合彩色血流超声多参数对胎盘植入性疾病的诊断效能。方法：2019年11月-2021年12月于我院收治的产前超声诊断为前置胎盘的孕妇共计62例,其中44例超声诊断合并了胎盘植入的孕妇。所有孕妇产前均进行经腹灰阶检查、经腹彩色超声检查和二者联合检查胎盘植入性疾病,通过分析胎盘植入性疾病筛查结果,评价产前超声经腹灰阶联合彩色血流超声多参数对胎盘植入性疾病的筛查效能。结果：（1）通过灰阶超声诊断检出胎盘植入的灵敏度为73.42 %,特异度为86.54 %;（2）通过彩色超声诊断检出胎盘植入的灵敏度为76.89%,特异度为89.07 %;（3）经腹灰阶联合彩色血流超声多参数诊断检出胎盘植入的灵敏度为87.79 %,特异度为90.36 %;（4）经腹灰阶检查、经腹彩色超声检查和二者联合检查对胎盘植入性疾病筛查阳性率分别为56.45 %、62.90 %和67.74 %,二者联合检查对产前胎盘植入性疾病筛查阳性率显著高于经腹灰阶检查和经腹彩色超声检查（P<0.05）。（5）二者联合检查的敏感度为72.26 %,特异度为90.54 %,阳性比为95.55 %,诊断比值比为78.89 %。结论：产前经腹灰阶联合彩色血流超声多参数对胎盘植入性疾病的诊断有较高的灵敏度和特异度,值得临床推广应用。     

超声引导改良外周静脉导入中心静脉置管术临床应用经验

目的:探讨超声引导下改良的外周静脉导入中心静脉置管术(Peripherally Inserted Central Catheter,PICC)的临床应用。方法:对42例有恶性肿瘤病史需行PICC置管、浅静脉直视下不明显或触摸不到、不适合盲穿患者42例进行超声引导下改良的PICC术。改良方法包括穿刺支架超声引导以及用一次性使用麻醉用针替代Seldinger包内的穿刺针进行,并与23例标准PICC法对比分析穿刺成功率及穿刺并发症发生率。结果:两种方法穿刺成功率均为100%,其中改良PICC患者41例穿刺一次成功,一次成功率为97.6%;标准PICC患者21例穿刺一次成功,一次成功率为91.3%。两种方法一次成功率差异无统计学意义(P0.05)。42例改良患者中发生2例并发症,包括局部水肿1例及导管异位1例;23例标准PICC患者中发生6例并发症,包括局部水肿2例,导管异位1例,静脉炎1例及局部感染2例。两种方法并发症发生率差异有统计学意义(P=0.019)。结论:超声引导下改良的PICC术一次成功率高,并发症少,值得临床推广。     

Generalization and categorization of spectral colors in goldfish. II. Experiments with two and six training wavelengths

In part I of this study (Kitschmann and Neumeyer 2005), goldfish categorized spectral colors only in the sense that wavelengths in a range of about twice as large as the just noticeable difference were treated as similar to a given training wavelength. Now, we trained goldfish on more than one wavelength to prevent very accurate learning. In one experiment goldfish were trained on six adjacent wavelengths with equal numbers of rewards, and, thus, equal numbers of learning events. Generalization tests showed that some wavelengths were chosen more often than others. This indicated that certain spectral ranges are either more attractive or more easily remembered than others. As this is a characteristic of the “focal” colors or centers of color categories in human color vision, we interpret the findings in goldfish accordingly. We conclude (Figs. 5 and 6) that there are four categories in spectral ranges approximately coinciding with the maximal sensitivities of the four cone types, and three categories in-between. Experiments with two training colors indicate that there is no direct transition between categories analogous to human “green” and “red”, but that there is a color analogous to human “yellow” in-between (Figs. 2, 3; Table 1).     

Lens optical properties in the eyes of large marine predatory teleosts

The optical properties of the crystalline lenses were studied in a variety of large predatory teleosts (bony fishes) that forage in the open ocean, some of them at considerable depths. We found the first fish lenses that are free of measurable longitudinal spherical aberration, i.e., are perfectly monofocal, in contrast to the multifocal lenses that are typical for smaller fishes living close to the surface. In fact, none of the lenses investigated in this study were clearly multifocal. Most, but not all, of the lenses had long normalized focal lengths (focal length/lens radius) of up to 3.3 lens radii. A monofocal lens of long focal length, combined with spectrally suitably placed cone pigments, may be the optimal solution for vision of high spatial and spectral resolutions in a habitat where the available spectrum of light is limited.     

千锤百炼出精品, 一部值得推荐的好教材

由武汉大学沈萍教授和陈向东教授主编的《微生物学》(彩色版)是国内第1部4色印刷的微生物学教材, 是经过多名微生物学专家的共同努力精心完成的。在注重加强基础的同时, 还突出新颖性和启发性; 将理论与实践有机结合, 对于学生自助学习能力的培养和创造力的培养很有帮助。精心设计的大量插图的运用也为该教材增色不少。     

COLOR ASSORTATIVE MATING CONTRIBUTES TO SYMPATRIC DIVERGENCE OF NEOTROPICAL CICHLID FISH

It is still debated vigorously whether sexual selection can result in speciation without physical barriers to gene flow. In this study, we used field data and molecular methods to investigate the gold–normal color polymorphism in two endemic cichlid fish species of crater lake Xiloá, Nicaragua. We found significant assortative mating by color in both Amphilophus xiloaensis and A. sagittae . Focusing on A. xiloaensis , microsatellite allele frequencies, an assignment test, and model-based cluster analysis demonstrates significant and clear genetic differentiation ( F _ST= 0.03) between gold and normal individuals in sympatry. In addition, we find genetic differentiation between all three sympatric and ecologically distinct Midas cichlid species of Lake Xiloá, A. amarillo , A. sagittae , and A. xiloaensis ( F _ST= 0.03 – 0.19), and clear genetic isolation of these species from their closest relative ( A. citrinellus ) in the neighboring great lake Managua. The A. xiloaensis gold morph is genetically more distinct from the lake's other two Midas cichlid species than is A. xiloaensis -normal. Thus, we have identified sexual isolation based on color that is evident in population genetics and mate choice. Our results suggest that sexual selection through color assortative mating may play an important role in incipient sympatric speciation in Midas cichlids of Nicaragua.     

乳腺浸润性导管癌96例影像诊断体会

目的：探讨全数字化乳腺摄影与彩色多普勒相结合对乳腺癌的诊断价值。方法：搜集经X线摄影及超声检查并经病理证实为乳腺浸润性导管癌的96例进行回顾性分析。结果：96例乳腺癌中,单发病灶83例,多发病灶13例。采用全数字化X线摄影单独诊断乳腺癌80例,诊断符合率83.33%,采用超声单独诊断乳腺癌87例,诊断符合率90.63%。结论：乳腺X线与超声相结合,诊断乳腺癌95例,诊断符合率99.06%,此二种检查综合诊断,可明显提高乳腺癌的诊断符合率,减少漏诊和误诊。