نتایج جستجو برای: transient species
تعداد نتایج: 670100 فیلتر نتایج به سال:
As two species diverge from one another, they become increasingly isolated by reproductive incompatibilities. New findings, however, undermine this evolutionary orthodoxy, showing that the first identified mammal speciation gene causes only transient incompatibility between diverging species.
background : cockroaches mechanically spread pathogenic agents, however, little is known about their gut microbiota. identification of midgut microbial community helps targeting novel biological control strategies such as paratransgenesis. here the bacterial microbiota of periplaneta americana midgut, were identified and evaluated for finding proper paratransgenesis candidate. methods : midgut ...
this research concentrates on the lithostratigraphy, biostratigraphy, microfacies and sedimentary environment of the asmari and gachsaran formations at southwest firuzabad. the thickness of the studied section in all 608.95 meters that 220.8 meters belong to the asmari formation and 387.95 meters belong to the gachsaran formation (champe and mol members). in the study area, the asmari formation...
آنچه به نام ضربه قوچ در شبکه های خط لوله شناخته می شود، شرایط گذرایی است که ممکن است به علت تغییرات سریع در شبکه ها، راه اندازی یا متوقف شدن پمپ ها و تغییر بار مصرفی توربین ها رخ دهد. در این حالت اغتشاشات وارده با سرعت صوت به صورت موج فشاری مثبت یا منفی در سیستم حرکت کرده و به علت تنش برشی دیواره مستهلک می شود. مقایسه نتایج میدانی و نظری نشان داده است که، مدل اصطکاکی ماندگار و شبه ماندگار به پ...
the cement gland (cg) is a transient organ, found in most anuran embryos and early larvae and located normally on the front of the head. its sticky secretion allows newly hatched larvae to attach to the egg jelly or to another support later and remain hidden and stationary until feeding starts. our ultrastructural studies showed that prominence structure of the cg in some species exists, but is...
How ecological, developmental and genetic mechanisms interact in the genesis and subsequent diversification of morphological novelties is unknown for the vast majority of traits and organisms. Here we explore the ecological, developmental, and genetic underpinnings of a class of traits that is both novel and highly diverse: beetle horns. Specifically, we focus on the origin and diversification ...
Question: Are seed mass and shape related to persistence in the soil seed bank among 54 species of the Israeli flora? Search method: Persistence was determined by soil seed bank investigations in which the fraction of non-germinated viable seeds was regarded as the persistent soil seed bank. When seedling emergence had ceased but before new seeds were shed, all soil from the upper 5 cm of 120 q...
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