Arterial Oxygen Saturation During Ascent to 5010 m: Heart Rate and AMS Scores

The hypothesis here is that tissues exposed to the hypoxia of altitude have increased blood flow so that the rate of arrival of oxygen is as rapid as normal. If the ascent is too rapid, the system starts to fail. The study involves an ascent to high altitude (5010 m) during which 59 subjects recorded their resting arterial oxygen saturation (SaO2), heart rate (HR) and Lake Louise acute mountain sickness (AMS) scores, twice daily. During the major ascent SaO2 fell progressively. In 42 subjects, HR increased in a highly significant, negative, relationship to SaO2. In 10 subjects heart rate (HR) remained unchanged. Three subjects showed extreme HR variability. Data were incomplete in four subjects. For nine of the subjects, showing the progressive HR versus SaO2 correlation during ascent, the sequence terminated with a lower HR than would be expected from the correlation so far. Individual AMS scores showed no correlation with SaO2 but averaged values from 19 of the subjects from each ‘one night’ stopover; showed a strong, negative, correlation. Average stopover HR values correlated negatively with the average SaO2 values. Cardiac output (CO) is likely to have increased during ascent as HR increased, since there is a progressive relationship between HR and cardiac output (CO). Hence, despite the progressive fall in SaO2, tissue oxygen delivery (DO2) would have remained close to normal in the 42 subjects who showed the significant HR: SaO2 relationship

Premarital sex and school dropout in Kenya: Can schools make a difference?

Although an overall decline has occurred in adolescent fertility in Kenya, the proportion of births to teenagers that takes place prior to marriage is rising. At the same time that premarital sex and childbearing have increased, educational participation has expanded considerably, especially for girls. Using data from nearly 600 adolescents aged 12-19 in combination with data collected from 33 primary schools that the adolescents attended, this paper explores whether certain aspects of the school environment affect the likelihood of early and unprotected sex among adolescent girls and boys in three districts of Kenya. Because of the concern with “schoolgirl pregnancy” in Kenya, the paper also explores the temporal relationship between premarital sex and pregnancy, and school dropout. The results suggest that, although neither the school nor the home influences whether boys engage in premarital sex, for girls, a school characterized by girl-friendly teachers and a gender-neutral atmosphere, and a home containing female role models and the extra support that two parents can provide, reduce the risk of premarital sex. On the other hand, girls are more likely to engage in premarital sex if they attend schools where considerable pressure to have sex is reported. The school environment also appears to have an impact on whether or not sexually active boys choose to use contraceptives. A gender-neutral environment leads to greater contraceptive use among boys, as do schools where students have greater knowledge of reproduction. Finally, even if certain school characteristics significantly affect the risk of premarital sex for girls, the data indicate that pregnancy is not the primary reason that girls leave school early

The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa.

BACKGROUND: Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. METHODS: The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. RESULTS: In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. CONCLUSIONS: This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new mosquito control tool effective at reducing disease transmission, although further field work in areas with filariasis transmission should be carried out to verify this. In addition, work targeting malaria vector mosquitoes should be carried out to see if these mosquitoes manifest the same behaviour modification after infection with B. bassiana conidia

The Development of a Nutrition Screening Tool for Mental Health Settings Prone to Obesity and Cardiometabolic Complications: Study Protocol for the NutriMental Screener

People living with serious mental illness (SMI) experience physical health complications at disproportionate rates to people without an SMI. Unhealthy dietary intake and disordered eating behaviors are key driving factors. There is a lack of valid nutrition-risk screening tools targeted to mental health services, and typically used nutrition-risk screening tools are not suitable for mental health services. This paper details the rationale and study protocol for development and validation of the NutriMental screener, a tool for use in clinical practice to identify service users who are at risk for common nutrition issues experienced by this population group and trigger referral to a specialist clinician. The development process includes five phases. Phase I is the development of nutrition-related domains of interest from screening tools used in mental health services. Phase II involves a literature review and service-user interviews to identify additional domains. Phase III consists of international workshops with relevant clinicians and persons with SMI to gain a consensus on questions to be included in the draft tool. Phase IV involves conducting multinational feasibility and preliminary validation studies. Phase V consists of performing formal validation studies. The development of a nutrition-risk screening tool for mental health services is a necessary step to help rectify the physical-health disparities and life-expectancy gap for people with SMI

L'évolution des causes de décès d'enfants en Afrique : une étude de cas au Sénégal avec la méthode d'autopsie verbale

Dans les pays où les malades sont rarement examinés par un médecin et où les registres médicaux sont insuffisants pour déterminer les causes de la mortalité, force est de recourir à d'autres sources pour obtenir ces informations. Une méthode de collecte d'informations sur les causes de décès par des non-médecins a été mise au point dans plusieurs pays en développement, dite méthode des "autopsies verbales" : après chaque décès, une enquête est effectuée auprès des familles, à partir de questionnaires standardisés portant sur les symptômes et l'histoire de la maladie qui a conduit au décès; Nous avons appliqué cette méthode à tous les décès d'enfants de moins de 5 ans, sur une période de 10 ans (1984-1993) dans la zone d'étude de Bandafassi, au Sénégal Oriental, où une population d'environ 8000 habitants est suivie depuis 25 ans par enquête démographique à passage annuel. Bien que le pourcentage de décès dont la cause demeure indéterminée par cette méthode reste élevé (de 30 à 40%), celle-ci nous a permis de détecter les maladies les plus meurtrières dans chaque classe d'âge et les principales variations des causes de la mortalité selon des facteurs démographiques (le sexe et l'âge) ou climatiques (la saison du décès). Enfin, la répétition de ces enquêtes chaque année sur 10 ans donne une idée des évolutions des causes de décès les plus importantes, ce qui permet d'évaluer le succès des programmes sanitaires mis en oeuvre, ou d'orienter ceux à venir. (Résumé d'auteur

ARMC 5 Variants and Risk of Hypertension in Blacks: MH- GRID Study.

Background We recently found that ARMC 5 variants may be associated with primary aldosteronism in blacks. We investigated a cohort from the MH - GRID (Minority Health Genomics and Translational Research Bio-Repository Database) and tested the association between ARMC 5 variants and blood pressure in black s. Methods and Results Whole exome sequencing data of 1377 black s were analyzed. Target single-variant and gene-based association analyses of hypertension were performed for ARMC 5, and replicated in a subset of 3015 individuals of African descent from the UK Biobank cohort. Sixteen rare variants were significantly associated with hypertension ( P=0.0402) in the gene-based (optimized sequenced kernel association test) analysis; the 16 and one other, rs116201073, together, showed a strong association ( P=0.0003) with blood pressure in this data set. The presence of the rs116201073 variant was associated with lower blood pressure. We then used human embryonic kidney 293 and adrenocortical H295R cells transfected with an ARMC 5 construct containing rs116201073 (c.*920T>C). The latter was common in both the discovery ( MH - GRID ) and replication ( UK Biobank) data and reached statistical significance ( P=0.044 [odds ratio, 0.7] and P=0.007 [odds ratio, 0.76], respectively). The allele carrying rs116201073 increased levels of ARMC5 mRNA , consistent with its protective effect in the epidemiological data. Conclusions ARMC 5 shows an association with hypertension in black s when rare variants within the gene are considered. We also identified a protective variant of the ARMC 5 gene with an effect on ARMC 5 expression confirmed in vitro. These results extend our previous report of ARMC 5's possible involvement in the determination of blood pressure in blacks

A poxvirus pseudokinase represses viral DNA replication via a pathway antagonized by its paralog kinase

Poxviruses employ sophisticated, but incompletely understood, signaling pathways that engage cellular defense mechanisms and simultaneously ensure viral factors are modulated properly. For example, the vaccinia B1 protein kinase plays a vital role in inactivating the cellular antiviral factor BAF, and likely orchestrates other pathways as well. In this study, we utilized experimental evolution of a B1 deletion virus to perform an unbiased search for suppressor mutations and identify novel pathways involving B1. After several passages of the ΔB1 virus we observed a robust increase in viral titer of the adapted virus. Interestingly, our characterization of the adapted viruses reveals that mutations correlating with a loss of function of the vaccinia B12 pseudokinase provide a striking fitness enhancement to this virus. In support of predictions that reductive evolution is a driver of poxvirus adaptation, this is clear experimental evidence that gene loss can be of significant benefit. Next, we present multiple lines of evidence demonstrating that expression of full length B12 leads to a fitness reduction in viruses with a defect in B1, but has no apparent impact on wild-type virus or other mutant poxviruses. From these data we infer that B12 possesses a potent inhibitory activity that can be masked by the presence of the B1 kinase. Further investigation of B12 attributes revealed that it primarily localizes to the nucleus, a characteristic only rarely found among poxviral proteins. Surprisingly, BAF phosphorylation is reduced under conditions in which B12 is present in infected cells without B1, indicating that B12 may function in part by enhancing antiviral activity of BAF. Together, our studies of B1 and B12 present novel evidence that a paralogous kinase-pseudokinase pair can exhibit a unique epistatic relationship in a virus, perhaps serving to enhance B1 conservation during poxvirus evolution and to orchestrate yet-to-be-discovered nuclear events during infection

The Fundamental Behavior of Timber-Concrete Composite Floors in Fire

Timber-concrete composite (TCC) floors have improved strength and stiffness when compared to timber-only floors, allowing for longer spans in buildings and improved life safety. However, North America does not have codes and standards that recognize TCC floors, particularly the improved life safety performance of these floors in fire. Therefore, alternate means and methods, structural fire engineering, or extensive structural testing is required for structural engineers to design the fire protection for TCC floors. This becomes a large burden on the building owner, as these calculation and testing methods are costly and add time to the project. The objective of this research is to fundamentally understand the behavior of TCC floors during a fire and benchmark existing analytical models for predicting the flexural capacity and deflection of TCC floors in fire against the experimentally collected data. This thesis presents an experimental investigation consisting of two experimental studies conducted to examine (1) properties of shear connectors used in TCC floors through ambient temperature direct shear tests and (2) the behavior of TCC floors through large-scale fire tests performed at the National Research Council (NRC) in Canada. An analytical investigation is performed consisting of benchmarking and improving existing analytical models for the prediction of flexural capacity and deflection of TCC floors during a standard fire. These models are benchmarked against experimental data from the experimental investigation and from previously published large-scale fire tests of TCC floors. The results indicate that TCC floors have improved fire performance when compared to mass timber floors. The calculated experimental char rates are comparable to prescribed char rates for timber-only, indicating existing char rates can be used for TCC floors. The presence of shear connectors and a concrete topping was found to have a negligible impact on the char rate of timber. Existing analytical models can reasonably predict the temperature-dependent flexural capacity and deflection of TCC floors in fires. This research quantifies the force-slip behavior of the shear connectors used as well as calculating the slip modulus of TCC floor shear connectors using the simplified design method (CEN 2004a). The use of both shear connector slip moduli demonstrated comparable results when calculating deflection using existing analytical models. The work presented in this thesis is intended to aid practicing engineers in the design of TCC floors for fire

Vegetation structure moderates the effect of fire on bird assemblages in a heterogeneous landscape

Ecological theory predicting the impact of fire on ecological communities is typically focused on post-disturbance recovery processes or on disturbance-diversity dynamics. Yet the established relationship between vegetation structure and animal diversit

The Driver Has Control: Exploring Driving Performance with Varying Automation Capabilities

As vehicle automation becomes more capable and prevalent, an understanding of how drivers will interact with automation systems of varying capabilities will be of critical importance. In this study, we compare the performance of drivers on takeover of control from varying types of automation systems (single-function and combined function). Participants drove a 20-minute course with sections of automated driving, and with several traffic events designed to elicit a driver response. Structured transfers of control between automated and manual driving modes occurred following a 7-second countdown at fixed locations on the course. Significant differences were found between groups in terms of lanekeeping ability immediately after taking control following a period of automated vehicle control or partial driver/automation control, but significant differences were not found in accident evasion ability, even five seconds after resuming full control