When is sex environmentally determined?
نویسندگان
چکیده
منابع مشابه
Pattern does not equal process: exactly when is sex environmentally determined?
Of prime importance in evolutionary biology are the description of pattern and explanations of process. Frequently, however, multiple processes can explain a given pattern. Such cases require experimental protocols or research criteria to distinguish among alternatives so pattern can be critically assigned to process. Noteworthy examples of this approach include evaluating adaptations and ident...
متن کاملWhen every $P$-flat ideal is flat
In this paper, we study the class of rings in which every $P$-flat ideal is flat and which will be called $PFF$-rings. In particular, Von Neumann regular rings, hereditary rings, semi-hereditary ring, PID and arithmetical rings are examples of $PFF$-rings. In the context domain, this notion coincide with Pr"{u}fer domain. We provide necessary and sufficient conditions for...
متن کاملWhen is a sex diVerence not a sex diVerence?
Brain sexual diVerentiation in mammals requires activity of gonadal hormones; organizational eVects of these steroids on brain development occur early in life while activational ones in adulthood ensure appropriate and timely sex-speciWc behaviors. This traditional view has long served as a reliable model for sexual diVerentiation of reproductively relevant brain structures. Here, we take a fre...
متن کاملWhen Is a Distribution Determined by Its Letter Values ?
Suppose that the differences between the successive letter values of a continuous symmetric distribution form a geometric progression. Under very simple regularity assumptions it is shown that the distribution is uniquely determined. As an application, a statistic based only on the letter values is constructed for testing the hypothesis that a data set is drawn from any given, completely specif...
متن کاملWhen Is a Group Action Determined by It’s Orbit Structure?
We present a simple approach to questions of topological orbit equivalence for actions of countable groups on topological and smooth manifolds. For example, for any action of a countable group Γ on a topological manifold where the fixed sets for any element are contained in codimension two submanifolds, every orbit equivalence is equivariant. Even in the presence of larger fixed sets, for actio...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Nature
سال: 1977
ISSN: 0028-0836,1476-4687
DOI: 10.1038/266828a0