limb bud first appears during the third week of gestation with the upper limb buds appearing a few days before the lower limb buds. complete absence of one or more limbs, called amelia, occurs prior to the eighth week of gestation. we report a case of amelia in a twin gestation.

in this paper, we investigate various kinds of extensions of twin-good rings. moreover, we prove that every element of an abelian neat ring r is twin-good if and only if r has no factor ring isomorphic to z2  or z3. the main result of [24] states some conditions that any right self-injective ring r is twin-good. we extend this result to any regular baer ring r by proving that every element of a...

In this paper, we investigate various kinds of extensions of twin-good rings. Moreover, we prove that every element of an abelian neat ring R is twin-good if and only if R has no factor ring isomorphic to‌ Z2  or Z3. The main result of [24] states some conditions that any right self-injective ring R is twin-good. We extend this result to any regular Baer ring R by proving that every elemen...

Behavior genetic approaches are becoming increasingly popular in political science. Many studies, to date, used a classical twin design to explore both political participation and ideological self-placement in Western democracies but studies in different political contexts, such as post-communist countries, are scarce. This paper is the first to explore the heritability of ideology and politica...

This paper estimates the causal effect of teenage childbearing on educational attainment using two cohorts of Australian twins and their relatives. Our main finding is that the negative effect of teenage childbearing on educational attainment appears to be small. We find no difference in educational attainment between teen mothers and their identical twin sisters. Data on the relatives of the t...

Let $D$ be a finite simple digraph with vertex set $V(D)$ and arcset $A(D)$. A twin signed total Roman dominating function (TSTRDF) on thedigraph $D$ is a function $f:V(D)rightarrow{-1,1,2}$ satisfyingthe conditions that (i) $sum_{xin N^-(v)}f(x)ge 1$ and$sum_{xin N^+(v)}f(x)ge 1$ for each $vin V(D)$, where $N^-(v)$(resp. $N^+(v)$) consists of all in-neighbors (resp.out-neighbors) of $v$, and (...

Background: Prediction of adverse perinatal and postnatal outcomes could be possible by using ultrasound Doppler evaluation, however there are some controversies regarding this issue in the literature. The goal of present study was to evaluate predictive value of Doppler indices in single and twin pregnancies during second trimester. Materials and Methods: This prospective study was conducted i...

In Multipregnancies, The careful control of Number of follicles in stimulation cycles and Number of embryos transferred in ART cycles is so important. Just twin pregnancies are reason for racial death (12- 15%). The risk for CP in twin pregnancies is 8 times more and for Triple is 47 times more than simple ones.Approximately all prenatal problems increase in multiple pregnancies and therefore t...

Let $D=(V,A)$ be a finite simple directed graph. A function$f:Vlongrightarrow {-1,0,1}$ is called a twin minus dominatingfunction (TMDF) if $f(N^-[v])ge 1$ and $f(N^+[v])ge 1$ for eachvertex $vin V$. The twin minus domination number of $D$ is$gamma_{-}^*(D)=min{w(f)mid f mbox{ is a TMDF of } D}$. Inthis paper, we initiate the study of twin minus domination numbersin digraphs and present some lo...

twin reversed arterial perfusion (trap) sequence is a syndrome with poor prognosis, seen only in monochorionic monozygotic twin pregnancies. the incidence is one in 35.000 births and one in 100 monozygotic twin pregnancies. it is characterized with a recipient fetus exhibiting lethal anomalies including acardia and a pump fetus. mortality is usually due to heart failure or premature labor cause...