Volume and homology of one-cusped hyperbolic 3-manifolds

Let M be a complete, finite-volume, orientable hyperbolic manifold having exactly one cusp. If we assume that pi_1(M) has no subgroup isomorphic to a genus-2 surface group, and that either (a) H_1(M;Z_p) has dimension at least 5 for some prime p, or (b) H_1(M;Z_2) has dimension at least 4, and the subspace of H^2(M;Z_2) spanned by the image of the cup product has dimension at most 1, then vol M > 5.06 If we assume that H_1(M;Z_2) has dimension at least 7, and that the compact core of M does not contain a genus-2 closed incompressible surface, then vol M > 5.06.Comment: 31 pages. This version agrees with the published version of the paper, except that an error in the published abstract has been corrected. In particular, the result which applies to manifolds with mod 2 homology of dimension at least 7 is stronger and has a shorter proof than the corresponding result in version

Comparative genomics of Burkholderia multivorans, a ubiquitous pathogen with a highly conserved genomic structure

The natural environment serves as a reservoir of opportunistic pathogens. A well-established method for studying the epidemiology of such opportunists is multilocus sequence typing, which in many cases has defined strains predisposed to causing infection. Burkholderia multivorans is an important pathogen in people with cystic fibrosis (CF) and its epidemiology suggests that strains are acquired from non-human sources such as the natural environment. This raises the central question of whether the isolation source (CF or environment) or the multilocus sequence type (ST) of B. multivorans better predicts their genomic content and functionality. We identified four pairs of B. multivorans isolates, representing distinct STs and consisting of one CF and one environmental isolate each. All genomes were sequenced using the PacBio SMRT sequencing technology, which resulted in eight high-quality B. multivorans genome assemblies. The present study demonstrated that the genomic structure of the examined B. multivorans STs is highly conserved and that the B. multivorans genomic lineages are defined by their ST. Orthologous protein families were not uniformly distributed among chromosomes, with core orthologs being enriched on the primary chromosome and ST-specific orthologs being enriched on the second and third chromosome. The ST-specific orthologs were enriched in genes involved in defense mechanisms and secondary metabolism, corroborating the strain-specificity of these virulence characteristics. Finally, the same B. multivorans genomic lineages occur in both CF and environmental samples and on different continents, demonstrating their ubiquity and evolutionary persistence

The diameter of the set of boundary slopes of a knot

Let K be a tame knot with irreducible exterior M(K) in a closed, connected, orientable 3--manifold Sigma such that pi_1(Sigma) is cyclic. If infinity is not a strict boundary slope, then the diameter of the set of strict boundary slopes of K, denoted d_K, is a numerical invariant of K. We show that either (i) d_K >= 2 or (ii) K is a generalized iterated torus knot. The proof combines results from Culler and Shalen [Comment. Math. Helv. 74 (1999) 530-547] with a result about the effect of cabling on boundary slopes.Comment: This is the version published by Algebraic & Geometric Topology on 29 August 200

Planning and assessing to improve campus--community engagement

Two methods for assessing the scholarship of engagement at the institutional level are presented: (a) the Comprehensive Assessment of the Scholarship of Engagement (CASE), a systematic method that compiles information about service learning and community engagement, identifies campus strengths, and prioritizes planning areas, and (b) an institutional portfolio that provides a rich data base of descriptive and evaluative information

Cost-effectiveness of community-based strategies for blood pressure control in a low-income developing country: findings from a cluster-randomized, factorial-controlled trial.

BACKGROUND: Evidence on economically efficient strategies to lower blood pressure (BP) from low- and middle-income countries remains scarce. The Control of Blood Pressure and Risk Attenuation (COBRA) trial randomized 1341 hypertensive subjects in 12 randomly selected communities in Karachi, Pakistan, to 3 intervention programs: (1) combined home health education (HHE) plus trained general practitioner (GP); (2) HHE only; and (3) trained GP only. The comparator was no intervention (or usual care). The reduction in BP was most pronounced in the combined group. The present study examined the cost-effectiveness of these strategies. METHODS AND RESULTS: Total costs were assessed at baseline and 2 years to estimate incremental cost-effectiveness ratios based on (1) intervention cost; (2) cost of physician consultation, medications, diagnostics, changes in lifestyle, and productivity loss; and (3) change in systolic BP. Precision of the incremental cost-effectiveness ratio estimates was assessed by 1000 bootstrapping replications. Bayesian probabilistic sensitivity analysis was also performed. The annual costs per participant associated with the combined HHE plus trained GP, HHE alone, and trained GP alone were $3.99,$3.34, and $0.65, respectively. HHE plus trained GP was the most cost-effective intervention, with an incremental cost-effectiveness ratio of$23 (95 confidence interval, 6-99) per mm Hg reduction in systolic BP compared with usual care, and remained so in 97.7 of 1000 bootstrapped replications. CONCLUSIONS: The combined intervention of HHE plus trained GP is potentially affordable and more cost-effective for BP control than usual care or either strategy alone in some communities in Pakistan, and possibly other countries in Indochina with similar healthcare infrastructure

Provider cost analysis supports results-based contracting out of maternal and newborn health services: an evidence-based policy perspective

Background There is dearth of evidence on provider cost of contracted out services particularly for Maternal and Newborn Health (MNH). The evidence base is weak for policy makers to estimate resources required for scaling up contracting. This paper ascertains provider unit costs and expenditure distribution at contracted out government primary health centers to inform the development of optimal resource envelopes for contracting out MNH services. Methods This is a case study of provider costs of MNH services at two government Rural Health Centers (RHCs) contracted out to a non-governmental organization in Pakistan. It reports on four selected Basic Emergency Obstetrical and Newborn Care (BEmONC) services provided in one RHC and six Comprehensive Emergency Obstetrical and Newborn Care (CEmONC) services in the other. Data were collected using staff interviews and record review to compile resource inputs and service volumes, and analyzed using the CORE Plus tool. Unit costs are based on actual costs of MNH services and are calculated for actual volumes in 2011 and for volumes projected to meet need with optimal resource inputs. Results The unit costs per service for actual 2011 volumes at the BEmONC RHC were antenatal care (ANC) visit USD$18.78, normal delivery US$ 84.61, newborn care US$16.86 and a postnatal care (PNC) visit US$ 13.86; and at the CEmONC RHC were ANC visit US$45.50, Normal Delivery US$ 148.43, assisted delivery US$167.43, C-section US$ 183.34, Newborn Care US$41.07, and PNC visit US$ 27.34. The unit costs for the projected volumes needed were lower due to optimal utilization of resources. The percentage distribution of expenditures at both RHCs was largest for salaries of technical staff, followed by salaries of administrative staff, and then operating costs, medicines, medical and diagnostic supplies. Conclusions The unit costs of MNH services at the two contracted out government rural facilities remain higher than is optimal, primarily due to underutilization. Provider cost analysis using standard treatment guideline (STG) based service costing frameworks should be applied across a number of health facilities to calculate the cost of services and guide development of evidence based resource envelopes and performance based contracting

Prevalence of cardiovascular and respiratory complications following trauma in patients with obesity

BACKGROUND: It is generally accepted that obesity puts patients at an increased risk for cardiovascular and respiratory complications after surgical procedures. However, in the setting of trauma, there have been mixed findings in regards to whether obesity increases the risk for additional complications. OBJECTIVE: The aim of this study was to identify whether obese patients suffer an increased risk of cardiac and respiratory complications following traumatic injury. METHODS: A retrospective analysis of 275,393 patients was conducted using the 2012 National Trauma Data Bank. Hierarchical regression modeling was performed to determine the probability of experiencing a cardiac or respiratory complication. RESULTS: Patients with obesity were at a significantly higher risk of cardiac and respiratory complications compared to patients without obesity [OR: 1.81; CI: 1.72-1.91]. Prevalence of cardiovascular and respiratory complications for patients with obesity was 12.6% compared to 5.2% for non-obese patients. CONCLUSIONS: Obesity is predictive of an increased risk for cardiovascular and respiratory complications following trauma

Simulation of the shape memory effect in a NiTi nano model system

The shape memory behavior of a NiTi nanoparticle is analyzed by molecular dynamics simulations. After a detailed description of the equilibrium structures of the used model potential, the multi variant martensitic ground state, which depends on the geometry of the particle, is discussed. Tensile load is applied, changing the variant configuration to a single domain state with a remanent strain after unloading. Heating the particle leads to a shape memory effect without a phase transition to the austenite, but by variant reorientation and twin boundary formation at a certain temperature. These processes are described by stress-strain and strain-temperature curves, together with a visualization of the microstructure of the nanoparticle. Results are presented for five different Ni concentrations in the vicinity of 50%, showing for example, that small deviations from this ideal composition can influence the critical temperature for shape recovery significantly.Comment: 7 pages, 4 figures; accepted for publication in the "Journal of Alloys and Compounds

Molecular Level Characterization of Diatom-Associated Biopolymers that Bind 234Th, ²³³PA, ²¹°Pb, and 7Be in Seawater: A Case Study With Phaeodactylum tricornutum

In order to investigate the importance of biogenic silica associated biopolymers on the scavenging of radionuclides, the diatom Phaeodactylum tricornutum was incubated together with the radionuclides Th-234, Pa-233, Pb-210, and Be-7 during their growth phase. Normalized affinity coefficients were determined for the radionuclides bound with different organic compound classes (i.e., proteins, total carbohydrates, uronic acids) in extracellular (nonattached and attached exopolymeric substances), intracellular (ethylene diamine tetraacetic acid and sodium dodecyl sulfate extractable), and frustule embedded biopolymeric fractions (BF). Results indicated that radionuclides were mostly concentrated in frustule BF. Among three measured organic components, Uronic acids showed the strongest affinities to all tested radionuclides. Confirmed by spectrophotometry and two-dimensional heteronuclear single quantum coherence-nuclear magnetic resonance analyses, the frustule BF were mainly composed of carboxyl-rich, aliphatic-phosphoproteins, which were likely responsible for the strong binding of many of the radionuclides. Results from this study provide evidence for selective absorption of radionuclides with different kinds of diatom-associated biopolymers acting in concert rather than as a single compound. This clearly indicates the importance of these diatom-related biopolymers, especially frustule biopolymers, in the scavenging and fractionation of radionuclides used as particle tracers in the ocean