Total root length as estimated from small sub-samples

A method is proposed for estimating the total length of a root system from sub-samples. This method is based on the measurement of the length and diameter of small pieces of roots, and on the measurements of the bulk density of root sub-samples. It is assumed that roots are cylinders with a given bulk density. The length and diameter of small root pieces are measured by image analysis. A weighted quadratic mean (W.Q.M.) root diameter is then calculated and used in estimating the root length. This W.Q.M. diameter is defined as the real mean diameter of an equivalent single root with the same length and volume as the tested root system. The accuracy of prediction is demonstrated for one theoretical root system. The standard deviation of estimation can be calculated using sampling simulations.     

灰胸薮鹛消化系统形态的初步研究

对灰胸薮鹛（Liocichla omeiensis）消化系统的形态学作了初步观察,结果表明,灰胸薮鹛舌前端有刺毛状结构,后端有一排尖端后指的栉状突,且中间小两边大;雄鸟在舌前端正中央还有一“v”形的凹缺,深约2．5mm;雌鸟食道颈段长为13．2mm,雄鸟为17．5mm;嗉囊雌鸟长7．5mm,雄鸟长8．4mm;食道胸段雌鸟长15．5mm,雄鸟长14．7mm;肌胃发达,具角质膜,腺胃乳突短而小;肠道长与体长基本相等,小肠较发达,雌鸟长153．7mm,占肠道总长92．6％,雄鸟为133mm和95％,具有双侧盲肠,占肠道总长的3．3％,大肠短,雌鸟仅占肠道7．5％,雄鸟仅占4．75％;肝为体内最大的消化腺,分左右两叶;胰位于十二指肠袢内,细长形,分三小叶。     

Two morphological types in the reproductive stock of three-spined stickleback,Gasterosteus aculeatus,in Lake Harutori,Hokkaido Island

Synopsis Two morphological types of the trachurus form (completely plated morph) of three-spined stickleback, Gasterosteus aculeatus, are found in Lake Harutori, Kushiro, east district of Hokkaido Island. For convenience, the two forms are referred to as ‘large type’ and ‘small type’ on the basis of body length (discrimination at 70 mm in length). The two types were examined for morphometric, meristic and reproductive characteristics. They differ in body length, the number of lateral plates, means of the 2nd dorsal spine length/body length and of the pelvic spine length/body length, the relationship between body length and head length, between body length and gonad weight, between body weight and gonad weight, and between body length and ovarian egg number; significant differences were present for each sex. These two types were compared with the anadromous stickleback migrating into the freshwater area near Lake Harutori to breed. The anadromous fish was morphologically much more similar to the large type than the small type. It is suggested that the large type is also an anadromous form and the small type is the permanent freshwater resident.     

贵州省鼠耳蝠属一新纪录——狭耳鼠耳蝠

2010年10月在贵州省荔波县进行翼手目动物调查过程中,于荔波县洞塘乡捕获14只鼠耳蝠,经鉴定为狭耳鼠耳蝠Myotisblythii。主要鉴别特征:体型中等,前臂长64.60(60.78～67.72)mm(n=14,SD=1.71);耳狭长;耳屏直而细长,顶端尖锐;第三指最长、第五指最短;后足长约为胫长之半;无距缘膜;尾长67.99(60.56～73.82)mm(n=14,SD=3.7);雄性个体无阴茎骨,阴茎长12.58(8.42～15.72)mm(n=5,SD=2.86);颅全长24.09(23.48～24.72)mm(n=6,SD=0.55);头骨窄长;听泡发达;矢状脊较低;上颌内门齿有1个主尖和1个小附尖,外门齿小,与上犬齿分离;第2上前臼齿(P3)稍位于齿列内侧。此种鼠耳蝠为贵州省翼手目新纪录。     

Y-chromosome length heteromorphisms in Delhi infants

One hundred and seventy normal male infants from Delhi were studied using the CBG technique to estimate Y-chromosome length heteromorphisms. The median class in Y/F [Y/F = total length of the Y chromosome/average total length of the F group chromosomes (19 and 20)] distribution was 0.75-0.79. The Y/F index in infants varied from 0.60 to 1.16 with a mean of 0.81 and a standard deviation of 0.09. A high incidence for very small (53.5 percent) and small (41.2 percent) categories of Y-chromosome length heteromorphisms was observed. Data were compared with other available reports; also possible mechanisms of the Y-chromosome length heteromorphisms and their role in ethnic/racial variation as well as in developmental disturbances are discussed. It is suggested there may be a need to redefine the long and short Y chromosome in a given population while studying different clinical disorders.     

四川自贡中侏罗世璧山上龙一新种

2001年春,自贡市永安乡村民王新民在自家花园附近的紫红色沙质泥岩里发现一批脊椎动物化石。自贡恐龙博物馆接到报告后,由舒纯康同志前往调查处理,并将这批化石发掘回馆。该化石为一具不完整蛇颈龙类骨架,因其左后肢带骨较完整,有必要对它进行报道。     

Meloidogyne microcephala n. sp. (Meloidogynidae), a Root-knot Nematode from Thailand

Meloidogyne microcephala n. sp. is described and illustrated from specimens obtained from tobacco (Nicotiana tabacum L.) in Thailand. The female perineal pattern usually has a low dorsal arch, coarse striae, and a series of small cuticular flaps around the tail terminus. The stylet of the female is 14.4 μm long, with large, square to rectangular stylet knobs, The distinctive male head region is narrow, small, and truncate with a low, flattened head cap. The stylet length is 20.6 μm, and the knobs are small, angular, and set off from the shaft. Mean length of second-stage juveniles is 457.5 μm, and stylet length is 9.3 μm. The tail tip in the juveniles is set off from the rest of the tail as a small finger-like projection. M. microcephala reproduces by mitotic parthenogenesis, and has a chromosome number of 2n = 36.     

鲶鱼小窝器官的后期发育及形态的研究

电感官包括结节器官(tuberous organ)和壶形器官(ampullary organ)二大类。前者仅存在于电鱼上,后者则在电鱼及某些非电鱼都有发现。对于淡水鲶鱼而言,其壶形器官又称为小窝器官(small pit organ)。行为实验表明某些鱼类的小窝器官有极高的电敏感性,能检测0.5—0.8 nA/cm~2的电流刺激(Peters,1974;Kalmijn,1976),同时有不少报告描述了它的显微和亚显微结构(Sato,1949,1956,1969;Wachtel,1969;Roth,1969)。但是对这种器官的发育过程的研究报告还不多。     

Divergence in style length and pollen size leads to a postmating‐prezygotic reproductive barrier among populations of Silene latifolia

A central tenet of speciation research is the need to identify reproductive isolating barriers. One approach to this line of research is to identify the phenotypes that lead to reproductive isolation. Several studies on flowering plants have shown that differences in style length contribute to reproductive isolation between species, leading us to consider whether style length could act as a reproductive barrier among populations of a single species. This could occur if style length varied sufficiently and pollen size covaried with style length. Populations of Silene latifolia exhibit variation in flower size, including style length, that is negatively correlated with annual precipitation. We show that this divergence in style length has a genetic basis and acts as a reproductive barrier: males from small‐flowered populations produced relatively small pollen grains that were poor at fertilizing ovules when crossed to females from large‐flowered populations, leading to a significant reduction in seed production. Manipulating the distance pollen tubes had to travel revealed that this failure was purely mechanical and not the result of other incompatibilities. These results show that style length acts as a postmating‐prezygotic reproductive barrier and indicate a potential link between ecotypic differentiation and reproductive isolation within a species.     

A new batfish,Coelophrys bradburyae (Lophiiformes: Ogcocephalidae) from Japan, with comments on the evolutionary relationships of the genus

A new ogcocephalid batfish,Coelophrys bradburyae, is described on the basis of a single specimen collected from the Pacific coast off Aomori, Japan, at a depth between 557–595 m. The species differs from others of the genus by having a small eye (7.1 in head length), short upper jaw (3.7 in head length), short pectoral and pelvic fins (length 3.0 and 9.6 in head length, respectively), small illicial cavity (width 5.3 in head length), and no bifurcated tubercles on the lateral surface of the body. A key to the species ofCoelophrys is given and the evolutionary relationships of the genus discussed based on cladistic analyses: the sister relationship withHalieutopsis was confirmed and possible paedomorphic states, including the globose body, proposed as having evolved secondarily from a flat-bodied ogcocephalid ancestor.     

Sepharose 4B as a matrix for affinity chromatography. A spin-labelling investigation using nitroxides as model ligands

Nitroxide spin labels were attached to CNBr-activated Sepharose 4B directly and through oligoglycines and oo-amino-carboxylic acids of varying length. The homogeneity of the carbohydrate environments of directly attached labels was investigated by measuring dipolar interactions between nitroxides as a function of solvation and of spin dilution with a diamagnetic analogue, as well as by electron exchange between the nitroxides and paramagnetic metal ions in solution. Only the exchange experiment revealed any inhomogeneity, suggesting that a small proportion of sites may be less accessible than the majority. The distances between sites were sufficiently small to allow, in principle, multiple-site interactions between quite small proteins in solution and immobilized ligands. Reorientation of the label at the matrix, characterized by the correlation time t, became more rapid with increasing spacer length n. For n > 12, the decrease in t was less pronounced. The two types of spacer behaved similarly. Thus an ideal spacer length for affinity separations is 12 atoms; this is in good agreement with data from a variety of affinity separations. The results of electron spin resonance studies of the effect of non-aqueous solvent on directly and indirectly labelled Sepharose 4B were used to suggest reasons why enzymes immobilized on Sepharose may be stabilized to denaturing solvents.     

The urogenital papilla in the Holarctic lamprey (Petromyzontidae)

Synopsis The urogenital papillae of 30 species of Holarctic lampreys were examined to determine if this structure has any taxonornic use. Total length, branchial length and papilla length were measured. A correlation between mean papilla length and mean total length of the species existed in males for parasitic species but not nonparasitic species, indicating a potential use in nonparasitic species. In nonparasitic species the most obvious differences existed in the papilla length: branchial length ratio. From the limited material available there appeared to be no geographic variation in this ratio, although there is a seasonal variation with the ratio increasing as, spawning approaches. It therefore appears that urogenital papilla length has taxonomic value in male nonparasitic lampreys, provided the specimens are collected in spawning condition. The female papilla is too small to be of use.     

蓝翅希鹛消化系统的初步研究

对6只(3♀,3♂)蓝翅希鹛的消化系统进行了解剖观察,结果表明:蓝翅希鹛的舌成细长三角形,雌、雄舌尖端差异显著:雌鸟舌尖端各有一根长刺毛,而雄鸟无此长刺毛;在舌前端正中央还有一"v"形的凹缺,使舌成二分叉,雌鸟分叉深约2.77 mm,雄鸟为1.63 mm。食道颈胸部分段不明显,食管长18.64~23.55 mm,嗉囊外观不明显。腺胃乳突短而小,分布均匀;肌胃发达,具角质膜。肠道长与体长基本相等,小肠较发达,雌鸟长100.90 mm,占肠道总长90.08%,雄鸟分别为102.52 mm和89.60%;具有双侧盲肠,但不发达,占肠道总长的2.3%~2.8%,右侧盲肠略大于左侧;直肠短,雌鸟仅占肠道8.55%,雄鸟占8.72%。肝为体内最大的消化腺,分左右两叶。胰位于十二指肠袢内,细长形,分二小叶。由消化道特征说明其食性是以食虫为主的杂食性鸟类。     

Sexual selection for small size in male mosquitofish (Gambusia holbrooki)

In many poeciliid fishes, large males which court females coexist with small males which sneak-copulate. It is unclear whether these two tactics represent two evolutionarily stable strategies or if sneaking is a conditional strategy adopted by small, unattractive males. We studied the success of sneaky copulation by looking for sperm in the gonoduct of females after they were kept for 48 h with a male. A logistic regression analysis showed that the probability of a female being inseminated increased with female length and decreased with male length. The length of the male relative to that of the female was the best predictor of success. This result was confirmed using virgin females, thereby excluding any possible confounding effect due to the release of sperm from previous copulations. Sperm counts suggested that large males do not compensate for their reduced copulatory success by releasing larger sperm numbers. Behavioural data indicate that the advantages to small males are twofold: they have a greater chance to approach females from behind without being detected, and manoeuvre better when inserting the gonopodium into the female''s gonoduct. The selective advantage of small size might explain male dwarfism in poeciliids. Our results also suggest that small males adopting the sneaky tactic may be as successful as large males adopting courtship, and that alternative mating strategies may be maintained by negative density-dependent selection.     

Morphological variation in Puya (Bromeliaceae): an allometric study

A group of representative species of the genus Puya was studied to determine if there are allometric relationships between vegetative and floral parts, whether these relationships correlate with their pollination system and if plant size is correlated with elevation and latitude. Fifty-three species representing the morphological variation and distribution of the genus were studied. Total plant height, as well as leaf, inflorescence, petal and sepal length were measured and these data subjected to univariate and multivariate analyses. To test for correlation between plant size and altitudinal and latitudinal distribution, ANOVAs were performed. When the pollination system of a species is known, additional multivariate and univariate analyses were also performed. The results indicate that the characters studied are correlated with a size component, exhibiting positive allometry for sepal and petal length and negative allometry for leaf length. Inflorescence length is an isometric character. There was no significant correlation between plant size and altitudinal or latitudinal distribution. The ANOVAs show that the only character correlated to pollinator type was petal length. Small plants with small flowers are correlated to pollinators such as insects, while medium to large plants with medium to large-sized flowers are correlated with pollinators such as birds and bats. Large plants have small flowers, that are more evident and attract more pollinators.     

贵州省发现侏伏翼

2010年6月在贵州省三都县进行翼手目动物标本采集,于水龙乡采集到1只雄性伏翼,经鉴定为侏伏翼(Pipistrellus tenuis).主要鉴别特征:体型甚小,前臂长30.64mm;颅全长12.04mm.耳较大,顶端钝圆;耳屏不足耳长的1/2.第1上门齿有2个齿尖.第1上前臼齿与犬齿基部充分接触,并稍位于齿列内侧.下...     

Anatomo-radiological study of the mesenteric small intestine using double-contrast enteroclysis. I. Position, length and diameter of the loops, thickness of their walls]

The Authors examined some anatomical parameters concerning the jejunum and ileum as the relationship between the loops, their extension, length, diameter and the wall thickness. 2019 patients have been studied by "double contrast small bowel enema". The results are in general according with the literature. Only the measure of the length changed, in fact it is shorter than that indicated in the literature.     

Sarcomere lengthening and tension drop in the latent period of isolated frog skeletal muscle fibers

A laser diffraction technique has been developed for registering small changes in sarcomere length. The technique is capable of resolving changes as small as 0.2 A in isolated frog skeletal muscle fibers. The small sarcomere lengthening that accompanies the drop in tension in the latent period of contraction was investigated. We suggest this lengthening be named latency elongation (LE). The LE is present in a completely slack fiber and must, therefore, be caused by a forcible lengthening process. Furthermore, the LE is dependent on the existence of an overlap between thin and tick filaments. The rate of elongation and the time interval between stimulation and maximum elongation may vary along the fiber. The maximum elongation was 3-5 A per sarcomere. At any instant the drop in tension is a product of the sum of sarcomere lengthenings along the fiber and the slope stiffness of the series elasticity. The latency relaxation (LR) could be registered in the sarcomere length range from 2.2 mum to 3.6-3.7 mum. The amplitude went through a sharp maximum at 3.0-3.1 mum. In the sarcomere length range from 2.2 to 2.8 mum the delay from onset to maximum LR was nearly proportional to the distance from the Z-line to the overlap zone. A working hypothesis is presented. It is suggested that the LE is caused by a lengthening of the thin filaments.     

Transposition of Plasmid-Borne Tn10 Elements Does Not Exhibit Simple Length-Dependence

The transposition frequencies of Tn10 elements from the bacterial chromosome to an F epitome decrease 40% for every kilobase increase in transposon length. The basis for this relationship is not known. We have now examined complemented transposition of defective Tn10 elements off small multicopy plasmids. We find that length dependence in this situation is either reduced or absent, depending on the specific class of transposition events involved. These observations can be interpreted as evidence against the model that chromosomal length dependence occurs because of decay of a transposition-associated replicative complex. This interpretation is consistent with unrelated experiments suggesting that Tn10 transposition is normally nonreplicative. Alternative explanations of length dependence phenomena are discussed.     

Neurohormonal alteration of integrative properties of the cardiac ganglion of the lobster Homarus americanus.

The spontaneous burst discharges of isolated lobster (Homarus americanus) cardiac ganglia were recorded with a spaced array of electrodes. Small regions (less than 1 mm) of the ganglion were exposed to the cardioexcitor neurohormone in extracts of pericardial organs (XPO) or to 10(-5) M 5-hydroxytryptamine (5HT). All axons were excited (increased mean firing frequency, f) by both substances, but only by applications in the region between the soma (but excluding it) and proximal site of impulse initiation. Units not so exposed changed their f relatively little despite f increases of as much as threefold in exposed units and changes in burst rate and overall length. Regularity and grouping of all impulse activity into bursts was never disturbed. 5HT increases burst rate at any point of application. The increases are larger if small cells are affected than if only large cells are exposed. Burst length decreases except when the pacemaker is affected. In contrast, XPO affects neither burst rate or length unless small cells are affected. Length is increased if non-pacemaker small cells are affected; both rate and length increase if the pacemaker is affected. The pacemaker usually exhibits an f of intermediate value. Rate changes are not simply related to its f. A small cell can "burst" in the absence of impulses from any other cells. XPO may enhance endogenous "driver potentials," while 5HT may excite by depolarizing at limited sites.