Heegaard Floer homology and alternating knots

In an earlier paper, we introduced a knot invariant for a null-homologous knot K in an oriented three-manifold Y, which is closely related to the Heegaard Floer homology of Y. In this paper we investigate some properties of these knot homology groups for knots in the three-sphere. We give a combinatorial description for the generators of the chain complex and their gradings. With the help of this description, we determine the knot homology for alternating knots, showing that in this special case, it depends only on the signature and the Alexander polynomial of the knot (generalizing a result of Rasmussen for two-bridge knots). Applications include new restrictions on the Alexander polynomial of alternating knots.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol7/paper6.abs.htm

Predictors of first-line antiretroviral therapy failure among adults and adolescents living with HIV/AIDS in a large prevention and treatment program in Nigeria.

BACKGROUND: A substantial number of persons living with HIV (PLWH) in Nigeria do not experience durable viral suppression on first-line antiretroviral therapy (ART). Understanding risk factors for first-line treatment failure informs patient monitoring practices and distribution of limited resources for second-line regimens. We determined predictors of immunologic and virologic failures in a large ART delivery program in Abuja, Nigeria. METHODS: A retrospective cohort study was conducted at the University of Abuja Teaching Hospital, a tertiary health care facility, using data from February 2005 to December 2014 in Abuja, Nigeria. All PLWH aged ≥ 15 years who initiated ART with at least 6-month follow-up and one CD4 measurement were included. Immunologic failure was defined as a CD4 decrease to or below pre-ART level or persistent CD4  1000 copies/mL after at least 6 months of ART and enhanced adherence counselling. HIV drug resistance (Sanger sequences) was analyzed using the Stanford HIV database algorithm and scored for resistance to common nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Univariate and multivariate log binomial regression models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Of 12,452 patients followed, a total of 5928 initiated ART with at least 6 months of follow-up and one CD4 measurement. The entry point for 3924 (66.2%) was through the program's own voluntary counseling and testing (VCT) center, while 1310 (22.1%) were referred from an outside clinic/program, 332 (5.6%) in-patients, and 373 (6.3%) through other entry points including prevention of mother to child transmission (PMTCT) and transferred from other programs. The mean CD4 at enrollment in care was 268 ± 23.7 cells per mm3, and the mean HIV-1 RNA was 3.3 ± 1.3.log10 copies/mL. A total of 3468 (80.5%) received nevirapine (NVP) and 2260 (19.5%) received efavirenz (EFV)-based regimens. A total of 2140 (36.1%) received tenofovir (TDF); 2662 (44.9%) zidovudine (AZT); and 1126 (19.0%) stavudine (d4T). Among those receiving TDF, 45.0% also received emtricitabine (FTC). In a multivariate model, immunologic failure was more common among PLWH with female gender as compared to male [RR (95% CI) 1.22 (1.07-1.40)] and less common among those who entered care at the program's VCT center as compared to other entry points [0.79 (0.64-0.91)], WHO stage 3/4 as compared to 1/2 [0.19 (0.16-0.22)], or CD4 200 + cells per mm3 as compared to lower [0.19 (0.16-0.22)]. Virologic failure was more common among PLWH who entered care at the program's VCT center as compared to other entry points [RR (95% CI) 1.45 (1.11-1.91) and those with CD4 < 200 cells per mm3 at entry into care as compared to higher [1.71 (1.36-2.16)]. Of 198 patient-derived samples sequenced during virologic failure, 42 (21%) were wild-type; 145 (73%) carried NNRTI drug resistance mutations; 151 (76.3%) M184I/V; 29 (14.6%) had ≥ 3 TAMs, and 37 (18.7%) had K65R, of whom all were on TDF-containing first-line regimens. CONCLUSIONS: In this cohort of Nigerian PLWH followed for a period of 9 years, immunologic criteria poorly predicted virologic failure. Furthermore, a subset of samples showed that patients failing ART for extended periods of time had HIV-1 strains harboring drug resistance mutations

Tryptophan degradation in irritable bowel syndrome: evidence of indoleamine 2,3-dioxygenase activation in a male cohort

<p>Abstract</p> <p>Background</p> <p>Irritable bowel syndrome (IBS) is a common disorder that affects 10–15% of the population. Although characterised by a lack of reliable biological markers, the disease state is increasingly viewed as a disorder of the brain-gut axis. In particular, accumulating evidence points to the involvement of both the central and peripheral serotonergic systems in disease symptomatology. Furthermore, altered tryptophan metabolism and indoleamine 2,3-dioxygenase (IDO) activity are hallmarks of many stress-related disorders. The kynurenine pathway of tryptophan degradation may serve to link these findings to the low level immune activation recently described in IBS. In this study, we investigated tryptophan degradation in a male IBS cohort (n = 10) and control subjects (n = 26).</p> <p>Methods</p> <p>Plasma samples were obtained from patients and healthy controls. Tryptophan and its metabolites were measured by high performance liquid chromatography (HPLC) and neopterin, a sensitive marker of immune activation, was measured using a commercially available ELISA assay.</p> <p>Results</p> <p>Both kynurenine levels and the kynurenine:tryptophan ratio were significantly increased in the IBS cohort compared with healthy controls. Neopterin was also increased in the IBS subjects and the concentration of the neuroprotective metabolite kynurenic acid was decreased, as was the kynurenic acid:kynurenine ratio.</p> <p>Conclusion</p> <p>These findings suggest that the activity of IDO, the immunoresponsive enzyme which is responsible for the degradation of tryptophan along this pathway, is enhanced in IBS patients relative to controls. This study provides novel evidence for an immune-mediated degradation of tryptophan in a male IBS population and identifies the kynurenine pathway as a potential source of biomarkers in this debilitating condition.</p

The Potential of the Geostationary Carbon Cycle Observatory (GeoCarb) to Provide Multi-scale Constraints on the Carbon Cycle in the Americas

The second NASA Earth Venture Mission, Geostationary Carbon Cycle Observatory (GeoCarb), will provide measurements of atmospheric carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and solar-induced fluorescence (SIF) from Geostationary Orbit (GEO). The GeoCarb mission will deliver daily maps of column concentrations of CO2, CH4, and CO over the observed landmasses in the Americas at a spatial resolution of roughly 10 × 10 km. Persistent measurements of CO2, CH4, CO, and SIF will contribute significantly to resolving carbon emissions and illuminating biotic processes at urban to continental scales, which will allow the improvement of modeled biogeochemical processes in Earth System Models as well as monitor the response of the biosphere to disturbance. This is essential to improve understanding of the Carbon-Climate connection. In this paper, we introduce the instrument and the GeoCarb Mission, and we demonstrate the potential scientific contribution of the mission through a series of CO2 and CH4 simulation experiments. We find that GeoCarb will be able to constrain emissions at urban to continental spatial scales on weekly to annual time scales. The GeoCarb mission particularly builds upon the Orbiting Carbon Obserevatory-2 (OCO-2), which is flying in Low Earth Orbit

The adoption of pottery on Kodiak Island: Insights from organic residue analysis

Pottery technology, originating in Northeast Asia, appeared in Alaska some 2800 years ago. It spread swiftly along Alaska’s coastline but was not adopted on Kodiak Island until around 500 cal BP, as part of the Koniag tradition. While in the southeast pottery was used extensively, people on the northern half of the island did not adopt the technology. What drove these patterns of adoption and non-adoption on Kodiak Island? To better understand the role of ceramic technology in the Koniag tradition we used organic residue analysis to investigate pottery function. Results indicate that pottery was used to process aquatic resources, including anadromous fish, but especially marine species. Based on archaeological and ethnographic data, and spatial analysis of pottery distributions and function, we hypothesize that Koniag pottery was a tool inherent to the rendering of whale oil on the southeast coast of Kodiak Island, supporting previous suggestions by Knecht (1995) and Fitzhugh (2001). When viewed in the broader historical context of major technological and social transformations, we conclude that social identity and cultural boundaries may also have played a role in the delayed and partial adoption of pottery on Kodiak Island

Microneurosurgical Anastomoses for Cerebral Ischemia [Contents]

From jacket: The purpose of this volume is to present a series of important papers on the rapidly growing surgical field of microneurosurgical anastomoses for cerebral ischemia. It includes papers on the indications and results of microneurosurgical bypass anastomoses; on the techniques used to study patients before and after surgery, including cerebral blood flow psychometic testing, etc.; and on the basic mechanisms of cerebral ischemia studies in animals. New ideas are suggested for techniques involving increased use of the occipital arteries and the development of vein, arterial, or prosthetic grafts in place of the STA (superficial temporal artery). Also discussed are the importance of measuring blood flow in the STA where possible, and the measurement of cerebral blood flow pre- and postoperatively to monitor the results. Psychometric studies are shown to be of importance pre- and postoperatively in addition to careful neurologic evaluation

Childhood in Sociology and Society: The US Perspective

The field of childhood studies in the US is comprised of cross-disciplinary researchers who theorize and conduct research on both children and youth. US sociologists who study childhood largely draw on the childhood literature published in English. This article focuses on American sociological contributions, but notes relevant contributions from non-American scholars published in English that have shaped and fueled American research. This article also profiles the institutional support of childhood research in the US, specifically outlining the activities of the ‘Children and Youth’ Section of the American Sociological Association (ASA), and assesses the contributions of this area of study for sociology as well as the implications for an interdisciplinary field.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Mathematical analysis and digital simulation of the control of erythropoiesis

A mathematical model is presented which represents the control system for erythropoiesis. In the model, it is postulated that the rate of erythropoiesis is controlled by a hormone, erythropoietin, which is released from the kidney in response to reduced renal oxygen supply. Equations are developed which relate erythropoietin release to arterial oxyhemoglobin concentration, and hemoglobin production to plasma erythropoietin concentration, with appropriate time delays. Effects of changes in plasma volume during hypoxia are included. The model is used with a digital computer to simulate the dynamic response of the erythropoietic system to a step decrease in the pO2 of inspired air. The response of the model compares favorably with experimental data obtained from mice subjected to different degrees of hypoxia.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33539/1/0000038.pd