Developing flow in S-shaped ducts. 1: Square cross-section duct

Laser-Doppler velocimetry was used to measure the laminar and turbulent flow in an S-duct formed with two 22.5 deg sectors of a bend with ratio of mean radius of curvature to hydraulic diameter of 7.0. The boundary layers at the inlet to the bend were about 25% and 15% of the hydraulic diameter for the laminar and turbulent flows, respectively. Pressure-driven secondary flows develop in the first half of the S-duct and persist into the second half but are largely reversed by the exit plane as a consequence of the change in the sense of curvature. There is, however, a region near the outer wall of the second bend where the redistribution of the streamwise isotachs results in a reinforcement of the secondary flow which was established in the first half of the S-duct. The net redistribution of the streamwise isotachs is comparable to that occurring in unidirectional bends of stronger curvature. The wall pressure distribution was also measured for the turbulent flow and quantifies the expected large variations in the longitudinal pressure gradient distributions which occur at different radial locations

Qualitative website analysis of information on birth after caesarean section

Date of Acceptance: 10/08/2015 © 2015 Peddie et al.Peer reviewedPublisher PD

Basin-Fill Stratigraphy, Quaternary History, and Paleomagnetics of the Eagle Flat Study Area, Southern Hudspeth County, Texas

Data and analyses of basin-fill stratigraphy, paleomagnetics, Quaternary history, and pseudo-fissures/fissures were acquired and interpreted by the Bureau of Economic Geology (BEG) in the Eagle Flat study area in southern Hudspeth County, Texas. These investigations were funded by the Texas Low-Level Radioactive Waste Disposal Authority (the Authority) as part of the evaluation of a proposed site for the Texas low-level radioactive waste repository. Data and information developed as a result of these investigations will be used to evaluate the proposed waste repository site and surrounding region and to provide data for performance assessment, design, and licensing activities. Basin-fill sediments are composed predominantly of sandy mud and mud; sands are abundant at the surface in the vicinity of the proposed repository site, and gravels are abundant at the base of the basin fill adjacent to the bedrock. Basin-fill thickness ranges from 163 ft (50 m) on the southeast side of the proposed site to 715 ft (218 m) on the northeast side of the proposed site. Basin-fill thickness is approximately 200 ft (61 m) on the west side of the proposed site. Coarser basin-fill deposits are interpreted as proximal alluvial fans and colluvium, and finer sands and muds are interpreted as ephemeral stream, distal alluvial fan, alluvial flat, and eolian deposits. At the proposed site, near-surface fine gravel and coarse to fine sand deposits exhibit characteristics consistent with fluvial deposition. Some well-sorted fine-grained sands have textures consistent with eolian sediments. Fine-grained sands and muds are interpreted as distal alluvial fan and ephemeral stream deposits.Bureau of Economic Geolog

Scaling of Hunter Gatherer Camp Size and Human Sociality

One of the most commonly-observed properties of human settlements, both past and present, is the tendency for larger settlements to display higher population densities. Work in urban science and archaeology suggests this densification pattern reflects an emergent spatial equilibrium where individuals balance movement costs with social interaction benefits, leading to increases in aggregate productivity and social interdependence. In this context, it is perhaps not surprising that the more temporary camps created by mobile hunters and gatherers exhibit a tendency to become less dense with their population size. Here we examine why this difference occurs and consider conditions under which hunter-gatherer groups may transition to sedentism and densification. We investigate the relationship between population and area in mobile hunter-gatherer camps using a dataset, representing a large cross-cultural sample, derived from the ethnographic literature. We present a model based on the interplay between social interactions and scalar stress for the relationship between camp area and group size that describes the observed patterns among mobile hunter-gatherers. The model highlights the tradeoffs between the costs and benefits of proximity and interaction that are common to all human aggregations and specifies the constraints that must be overcome for economies of scale and cooperation to emerge

An Approach to Web-Scale Named-Entity Disambiguation

We present a multi-pass clustering approach to large scale. wide-scope named-entity disambiguation (NED) oil collections of web pages. Our approach Uses name co-occurrence information to cluster and hence disambiguate entities. and is designed to handle NED on the entire web. We show that on web collections, NED becomes increasing), difficult as the corpus size increases, not only because of the challenge of scaling the NED algorithm, but also because new and surprising facets of entities become visible in the data. This effect limits the potential benefits for data-driven approaches of processing larger data-sets, and suggests that efficient clustering-based disambiguation methods for the web will require extracting more specialized information front documents

Lack of Restoration in Vivo by K+-Channel Modulators of Jejunal Fluid Absorption after Heat Stable Escherichia coli Enterotoxin (STa) Challenge

Enhanced potassium ion permeability at the enterocyte basolateral membrane is assumed to facilitate sustained chloride ion and fluid secretion into the intestinal lumen during episodes of secretory diarrhoeal disease. To examine this concept in vivo, two potassium ion channel blockers and a channel opener were coperfused with E. coli heat stable STa enterotoxin to determine whether such compounds improved or worsened the inhibited fluid absorption. In the STa (80 ng/mL) challenged jejunal loop, the fluid absorption rate of 28.6 ± 5.8 (14) μL/cm/hr was significantly below (P < .001) the normal rate of 98.8 ± 6.2 (17) μL/cm/hr. Intraluminal (300 uM) glibenclamide added to STa perfused loops failed to improve the inhibited fluid absorption rate, which was 7.4 ± 3.2 (6) μL/cm/hr on coperfusion with STa. Similarly, on coperfusion with 30 uM clotrimazole, the fluid absorption rate with STa present remained inhibited at 11.4 ± 7.0 (4) μL/cm/hr. On coperfusion with intraluminal 1 uM cromakalim, STa reduced fluid absorption significantly (P < .02) to 24.7 ± 8.0 (10) μL/cm/hr, no different from STa challenge in the absence of cromakalim. Infusion i.v. with these agents also failed to restore fluid absorption after STa challenge. These observations do not support the proposed potassium ion permeability event as a necessary corollary of enterotoxin-mediated secretion. This makes it unlikely that modulators of such permeability prevent enterocyte secretion in diarrhoeal disease