Interspecific comparative studies have shown that, in most taxa, postcopulatory sexual selection (PCSS) in the form of sperm competition drives the evolution of longer and faster swimming sperm. Work on passserine birds has revealed that PCSS also reduces variation in sperm size between males at the intraspecific level. However, the influence of PCSS upon intra-male sperm size diversity is poor...

• General sperm shape characterized by conical head • Eggs characterized as large spheres in vitelline membrane • Atlantic and Pacific populations’ spermatozoa show major morphological differences from each other (Landry et al. 2003) • Western Pacific species’ sperm head length measured twice that of Central Pacific (Marks et al. 2008). • Deep sea sperm head length elongated compared to shallow...

The objective of this study was to identify morphological measurements that best distinguish Moroccan Barcha and Atlas goat breeds. Ten measurements (body weight - BW, body length - BL, heart girth - HG, withers height - WH, rump height - WH, back length - BAL, neck length - NL, head length - HL, ear length - EL, and ear width - EW) of 876 adult animals of both sexes (547 Barcha and 329 Atlas) ...

Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantit...

in this study, hydraulic properties of low pressure drip irrigation systems were studied under laboratory conditions and using of the pipes that exist in iran. therefore, effect of various heads from 0.45 to 1.8m was evaluated for lateral pipe with outside diameter 32mm and length of 16, 30, 60 and also the lateral pipe with length 16 and outside diameter of 16, 20, 25 and 32mm, on hydraulic ch...

OBJECTIVES Anthropometric abnormalities of the mandible and neck may contribute to snoring in non-obese Asians. The study evaluated the clinical implications of mandible and neck measurements in non-obese Asian snorers. METHODS The external mandible and neck measurements (neck circumference, two lengths of neck, mandibular body angle, and lengths of mandibular ramus and body) were compared be...

Astyanax douradilho, new species, is described from the rio Tramandaí system, coastal drainage of Rio Grande do Sul State, Brazil. The new species is distinguished from its congeners by possessing 37-39 perforated scales along the lateral line, 3-5 maxillary tricuspid teeth, 22-24 branched anal-fin rays, absence of a conspicuous dark stripe from humeral region to caudal peduncle, two vertically...

heat stress is one of the main obstacles for crop production in many areas of the world including southwest of iran. in order to evaluation the effect of heat stress on yield, yield component, and mopho-phenological traits of wheat, an experiment was conducted during 2010-2011 under normal (optimum sowing date) and heat stress (late sowing date) conditions on 11 wheat genotypes including yavaro...