Crossing mice deficient in eNOS with placental-specific Igf2 knockout mice: A new model of fetal growth restriction

AbstractWe tested the hypothesis that crossing two mouse models of fetal growth restriction (FGR) of differing phenotype would induce more severe FGR than either model alone. Female endothelial nitric oxide synthase knockout mice (eNOS−/−) were mated with placental-specific Igf2 knockout males (P0). Resultant fetuses were no more growth restricted than those with P0 deletion alone. However, P0 deletion attenuated the reduced placental system A amino acid transporter activity previously observed in eNOS−/− mice. Manipulating maternal and fetal genotypes provides a means to compare maternal and fetal regulation of fetal growth

Sex differences in regional specialisation across the placental surface

There may be regional specialisation in structure and function across the placental surface. In Riyadh, Saudi Arabia, the length and the breadth of the placental surface at birth were highly correlated, but the breadth was more closely associated with the size of the baby. To replicate this we studied 321 pregnant Saudi women in the town of Baish. We measured the size of the newborn babies and their placentas.The association of the length and breadth of the placental surface on the baby's body size differed in boys and girls. Among boys the breadth had a stronger association with all birth measurements except crown–heel length. This was similar to the findings in Riyadh. Placental surface length was related to crown–heel length. For each centimetre in surface length, crown–heel length increased by 0.27 cm (95% CI 0.09–0.44, p = 0.004). Among girls placental surface breadth was related to crown–heel length, whereas surface length was related to birth weight, head and thigh circumferences. For each centimetre in surface breadth, crown–heel length increased by 0.33 cm (0.13–0.53, p = 0.001).We conclude that, within Saudi Arabia, there are both geographical and sex differences in regional specialisation across the placental surface. In the adverse circumstances of Baish, linked to the mothers' short stature, boys were smaller at birth than girls. Boys may have compensated for under-nutrition by increasing the depth of spiral artery invasion rather than by recruiting additional spiral arteries. Girls may have had more effective regional specialisation across the placental surfac

Independent set of intersection graphs of convex objects in 2D

Abstract. The intersection graph of a set of geometric objects is defined as a £¥¤§¦©¨����� � graph in which there is an edge between two ������������ ¨ nodes if. The problem of computing a maximum independent set in the in-tersection graph of a set of objects is known to �� � be-complete for most cases in two and higher dimensions. We present approximation algorithms for computing a maximum independent set of intersection graphs of convex objects �� � in. Specifically, given a set � of line segments in the plane with maximum independent set of � size, we present algorithms that find an independent set of size at ( � least ¦�������������¦©���������������� � ) in ��¦����� � time (�© � and ¦�������������¦©���������������� � ) in time ���� � ���������� �. For a set of � convex objects with maximum independent set of � size, we present an algorithm that finds an independent set of size at least in time ��¦���������¦©¨��� � , assuming that ¨ can be preprocessed in ��¦©¨� � time to answer certain primitive operations on these convex sets.

Scheduling and Packing Malleable Tasks with Precedence Constraints of Bounded Width

Abstract. We study two related problems in non-preemptive scheduling and packing of malleable tasks with precedence constraints to minimize the makespan. We distinguish the scheduling variant, in which we allow the free choice of processors, and the packing variant, in which a task must be assigned to a contiguous subset of processors. For precedence constraints of bounded width, we completely resolve the complexity status for any particular problem setting concerning width bound and number of processors, and give polynomial-time algorithms with best possible performance. For both, scheduling and packing malleable tasks, we present an FPTAS for the NP-hard problem variants and exact algorithms for all remaining special cases. To obtain the positive results, we do not require the common monotonous penalty assumption on processing times, whereas our hardness results hold even when assuming this restriction. With the close relation between contiguous scheduling and strip packing, our FP-TAS is the first (and best possible) constant factor approximation for (malleable) strip packing under special precedence constraints.

Automated lattice drawing

Abstract. Lattice diagrams, known as Hasse diagrams, have played an ever increasing role in lattice theory and fields that use lattices as a tool. Initially regarded with suspicion, they now play an important role in both pure lattice theory and in data representation. Now that lattices can be created by software, it is important to have software that can automatically draw them. This paper covers: – The role and history of the diagram. – What constitutes a good diagram. – Algorithms to produce good diagrams. Recent work on software incorporating these algorithms into a drawing program will also be covered. An ordered set P = (P, ≤) consists of a set P and a partial order relation ≤ on P. That is, the relation ≤ is reflexive (x ≤ x), transitive (x ≤ y and y ≤ z imply x ≤ z) and antisymmetric (x ≤ y and y ≤ x imply x = y). If P is finite there is a unique smallest relation ≺, known as the cover or neighbor relation, whose transitive, reflexive closure is ≤. (Graph theorists call this the transitive reduct of ≤.) A Hasse diagram of P is a diagram of the acyclic graph (P, ≺) where the edges are straight line segments and, if a < b in P, then the vertical coordinate for a is less than the one for b. Because of this second condition arrows are omitted from the edges in the diagram. A lattice is an ordered set in which every pair of elements a and b has a least upper bound, a ∨ b, and a greatest lower bound, a ∧ b, and so also has a Hasse diagram. These Hasse diagrams 1 are an important tool for researchers in lattice theory and ordered set theory and are now used to visualize data. This paper deals the special issues involved in such diagrams. It gives several approaches that have been used to automatically draw such diagrams concentrating on a three dimension force algorithm especially adapted for ordered sets that does particularly well. We begin with some examples. 1 In the second edition of his famous book on lattice theory [3] Birkhoff says these diagrams are called Hasse diagrams because of Hasse’s effective use of them but that they go back at least to H. Vogt, Résolution algébrique des équation, Paris, 1895.

IFPA Meeting 2011 workshop report I: Placenta: Predicting future health; roles of lipids in the growth and development of feto-placental unit; placental nutrient sensing; placental research to solve clinical problems – A translational approach

Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialized topics. At IFPA meeting 2011 there were twelve themed workshops, four of which are summarized in this report. These workshops related to both basic science and clinical research into placental growth and nutrient sensing and were divided into 1) placenta: predicting future health; 2) roles of lipids in the growth and development of feto-placental unit; 3) placental nutrient sensing; 4) placental research to solve clinical problems: a translational approach