The Oxytocin Product Correlates with Total Oxytocin Received during Labor: A Research Methods Study

Objective Total dose of oxytocin received during labor is an important variable in studies of human labor but is difficult to calculate. We sought to identify a surrogate measure for total dose of oxytocin received. Study Design For each subject receiving oxytocin during labor, the oxytocin total dose received in labor was calculated as the area under the curve. Maximal oxytocin infusion rate, total duration of oxytocin infusion, and the product of both, defined as the oxytocin product, were then each correlated with the total dose of oxytocin received using the Pearson's correlation coefficient. Results Oxytocin dosing data were available from 402 women at Duke and 6,907 women from Pithagore6. The two variables alone, or combined as the oxytocin product, demonstrated a high correlation with the oxytocin total dose (r > 0.7), with the oxytocin product demonstrating the highest (r > 0.9). This was true whether labor was induced or augmented and whether delivery was vaginal or cesarean. Conclusion The oxytocin product, composed of two easily obtained variables, demonstrated a very high correlation with total oxytocin dose received in labor and represents a simple and accurate surrogate for total dose of oxytocin received during labor. The oxytocin product can be used in clinical studies in which oxytocin dose is an important variable

Investigation of the ferromagnetic transition in the correlated 4d perovskites SrRu1−x_{1-x}Rhx_xO3_3

The solid-solution SrRu$_{1-x}$Rh$_x$O$_3$ ($0\le x \le1$) is a variable-electron-configuration system forming in the nearly-cubic-perovskite basis, ranging from the ferromagnetic 4$d^4$ to the enhanced paramagnetic 4$d^5$. Polycrystalline single-phase samples were obtained over the whole composition range by a high-pressure-heating technique, followed by measurements of magnetic susceptibility, magnetization, specific heat, thermopower, and electrical resistivity. The ferromagnetic order in long range is gradually suppressed by the Rh substitution and vanishes at $x \sim 0.6$. The electronic term of specific-heat shows unusual behavior near the critical Rh concentration; the feature does not match even qualitatively with what was reported for the related perovskites (Sr,Ca)RuO$_3$. Furthermore, another anomaly in the specific heat was observed at $x \sim 0.9$.Comment: Accepted for publication in PR

Simulation of dimensionality effects in thermal transport

The discovery of nanostructures and the development of growth and fabrication techniques of one- and two-dimensional materials provide the possibility to probe experimentally heat transport in low-dimensional systems. Nevertheless measuring the thermal conductivity of these systems is extremely challenging and subject to large uncertainties, thus hindering the chance for a direct comparison between experiments and statistical physics models. Atomistic simulations of realistic nanostructures provide the ideal bridge between abstract models and experiments. After briefly introducing the state of the art of heat transport measurement in nanostructures, and numerical techniques to simulate realistic systems at atomistic level, we review the contribution of lattice dynamics and molecular dynamics simulation to understanding nanoscale thermal transport in systems with reduced dimensionality. We focus on the effect of dimensionality in determining the phononic properties of carbon and semiconducting nanostructures, specifically considering the cases of carbon nanotubes, graphene and of silicon nanowires and ultra-thin membranes, underlying analogies and differences with abstract lattice models.Comment: 30 pages, 21 figures. Review paper, to appear in the Springer Lecture Notes in Physics volume "Thermal transport in low dimensions: from statistical physics to nanoscale heat transfer" (S. Lepri ed.

Magnetization and dimerization profiles of the cut two-leg spin ladder and spin-1 chain

The physical properties of the edge states of the cut two-leg spin ladder are investigated by means of the bosonization approach. By carefully treating boundary conditions, we derive the existence of spin-1/2 edge states in the spin ladder with a ferromagnetic rung exchange and for the open spin-1 Heisenberg chain. In contrast, such states are absent in the antiferromagnetic rung coupling case. The approach, based on a mapping onto decoupled semi-infinite off-critical Ising models, allows us to compute several physical quantities of interest. In particular, we determine the magnetization and dimerization profiles of the cut two-leg spin ladder and of the open biquadratic spin-1 chain in the vicinity of the SU(2)$_2$ WZNW critical point.Comment: RevTeX 4, no figure, 26 page

The PHENIX Experiment at RHIC

The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

Social Network Analysis: Recent Achievements and Current Controversies

Network analysis has grown rapidly over the past two decades, but criticisms of the approach have increased as well This article focuses on several accomplishments and unresolved problems of the network approach In the first section. I illustrate the value of the network model in several substantive areas. focusing on studies of centrahty and power, network subgroups, and interorganizational relations I then discuss three issues over which the approach has provoked controversy the relation between network analysis and rational choice theory; the role of norms and culture, and the question of human agency I conclude with some examples of how network theorists are addressing these problemsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68023/2/10.1177_000169939403700403.pd

Modelling germ cell development in vitro

Germ cells have a critical role in mediating the generation of genetic diversity and transmitting this information across generations. Furthermore, gametogenesis is unique as a developmental process in that it generates highly-specialized haploid gametes from diploid precursor stem cells through meiosis. Despite the importance of this process, progress in elucidating the molecular mechanisms underpinning mammalian germ cell development has been retarded by the lack of an efficient and reproducible system of in vitro culture for the expansion and trans-meiotic differentiation of germline cells. The dearth of such a culture system has rendered the study of germ cell biology refractory to the application of new high-throughput technologies such as RNA interference, leaving in vivo gene-targeting approaches as the only option to determine the function of genes believed to be involved in gametogenesis. Recent reports detailing the derivation of gametes in vitro from stem cells may provide the first steps in developing new tools to solve this problem. This review considers the developments made in modelling germ cell development using stem cells, and some of the challenges that need to be overcome to make this a useful tool for studying gametogenesis and to realize any future clinical application

Modelling soil water balance and root water uptake in cotton grown under different soil conservation practices in the Indo-Gangetic Plain

Although soil conservation practices are being promoted as better environmental protection technologies than traditional farmers’ practice, limited information is available on how these practices affect soil water balance and root water uptake. The root water uptake (RWU) patterns of cotton grown under soil conservation practices and soil water balance in cotton (Gossypium hirsutum L.) fieldsunder a cotton-wheat (Triticum aestivum L.) cropping system were analyzed using the Hydrus-2D model. The treatments were: conventional tillage (CT), zero tillage (ZT), permanent narrow beds (PNB), permanent broad beds (PBB), ZT with residue (ZT+R), PNB with residue (PNB+R) and PBB with residue (PBB+R). Results in the third year of the cotton crop indicated that the surface (0–15cm layer) field saturated hydraulic conductivity in both PNB and PBB plots were similar and were significantly higher than in the ZT plots. Computed potential transpiration rates (Trp) under CT were lower than in other treatments, due to less radiation interception and lower Leaf Area Index (LAI). Both PNB and PBB plots had higher Trp and crop yields than CT plots, which were further improved by residue retention. Predicted soil water content (SWC) patterns during the simulation periods of third and fourth years showed strong correlation (R2=0.88, n=105, P<0.001, the root mean square error (RMSE)=0.025, and the average relative error (AVE)=7.5% for the third year and R2=0.81, n=105, P<0.001, RMSE=0.021, and AVE=9% for the fourth year) with the actual field measured SWCs. Cumulative RWU (mm) were in the order: ZT (143