26,513 research outputs found
\ud A Tanzanian Perspective on the Nutrition Transition and its\ud Implications for Health\ud
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The purpose of this paper is to describe social and economic changes related to shifts in diet and activity and to present prevalences for chronic diseases associated with the nutrition transition. Observations about social changes are descriptive, based on published reports and personal observations. Prevalence and trends data are based on a Ministry of Health published report and, for infants and toddlers, on primary data. Disease prevalences for diabetes mellitus and hypertension are taken from four sites, representing underdeveloped, semi-developed and well-developed rural communities and Dar es Salaam, the largest city in Tanzania. The prevalences of underweight and overweight for infants and toddlers are taken from a small periurban clinic in Tanzania. Adults over 15 years of age are included in the prevalence data for chronic disease. The urban sample is stratified by occupation and ethnicity. The data for infants and toddlers include newborns to those aged 23 months. An increase in the prevalence of diabetes and hypertension was observed. Simultaneously, there have been rapid changes in diet and physical activity related to urbanisation and modernisation. The highest prevalences for diabetes and hypertension were among high-ranking executives. The increase in chronic disease could be related to the rise in the number of high-ranking executives. Simultaneously, per capita income has gone down, and malnutrition prevalence has risen. Programmes are being developed to simultaneously monitor trends in overweight while preventing protein-energy malnutrition\ud
and micronutrient deficiency.\u
A numerical study of the role of vertical structure of vorticity during tropical cyclone genesis
An eight-level axisymmetric model with simple parameterizations for clouds and the atmospheric boundary layer was developed to examine the evolution of vortices that are precursors to tropical cyclones. The effect of vertical distributions of the vorticity, especially that arising from a merger of mid-level vortices, has been studied to provide support for a new vortex-merger theory
of tropical cyclone genesis. The basic model was validated with the analytical results available for the spin-down of axisymmetric vortices. With the inclusion of the cloud and boundary layer parameterizations, the evolution of deep vortices into hurricanes and the subsequent decay is simulated quite well. Effects of several parameters such as initial vortex strength, radius of maximum winds, sea surface temperature and latitude (Coriolis parameter) on the evolution were examined.
A new finding is the manner in which mid-level vortices of the same strength decay and how, on simulated merger of these mid-level vortices, the resulting vortex amplifies to hurricane strength in a realistic time-frame. The importance of the sea-surface temperature on evolution of full vortices has been studied and explained. Also it is found that the strength of the surface vortex determines the time taken by the deep vortex to amplify to hurricane strength
Socio-demographic influences on trends of fish consumption during later adult life in the Whitehall II study
Our aim was to investigate how socio-demographic factors influence trends and age-related trajectories of fish consumption. We examined consumption of total, fried and recommended fish (white and oily fish. and shellfish) in the Whitehall 11 study over I I years in participants aged 39-59 years at phase 3. The cohort included 8358 British civil servants who completed a FFQ at phase 3 (1991-3). phase 5 (1997-9. n 5430) and phase 7 (2002-4 n 5692). Occupational grade. ethnicity, marital and retirement status were collected at each phase. To analyse changes in age-related trends of fish intake over time according to socio-demographic characteristics. we applied a random mixed-effect model. Over the follow-up a significant increase in consumption of 'recommended' (mean: 1.85 to 2.22 portions/week) and total fish (mean: 2.32 to 2.65 portions/week) and a decreasing trend in fried-fish intake (mean: 0.47 to 0.43 portions/week) was observed. Recommended. fried and total fish consumption differed by occupational status, ethnicity. marital Status and sex. The trend of age-related fish intake diverged significantly by ethnicity. In South Asian participants (n 432). slope of recommended-fish consumption was significantly higher compared with white participants (0.077 v. 0.025 portions/week per year). For black participants (n 275) slope of fried-fish intake was significantly higher compared with white participants (0.0052 v. -0.0025 portions/week per year). In terms of public health. our descriptive and analytical work allows detailed Understanding of the impact of socio-demographic factors oil fish intake and its age-related trends. Such information is Valuable for food policies that seek to promote health equity
Statistical inference and spatial patterns in correlates of IQ
Cross-national comparisons of IQ have become common since the release of a large dataset of international IQ scores. However, these studies have consistently failed to consider the potential lack of independence of these scores based on spatial proximity. To demonstrate the importance of this omission, we present a re-evaluation of several hypotheses put forward to explain variation in mean IQ among nations namely: (i) distance from central Africa, (ii) temperature, (iii) parasites, (iv) nutrition, (v) education, and (vi) GDP. We quantify the strength of spatial autocorrelation (SAC) in the predictors, response variables and the residuals of multiple regression models explaining national mean IQ. We outline a procedure for the control of SAC in such analyses and highlight the differences in the results before and after control for SAC. We find that incorporating additional terms to control for spatial interdependence increases the fit of models with no loss of parsimony. Support is provided for the finding that a national index of parasite burden and national IQ are strongly linked and temperature also features strongly in the models. However, we tentatively recommend a physiological – via impacts on host–parasite interactions – rather than evolutionary explanation for the effect of temperature. We present this study primarily to highlight the danger of ignoring autocorrelation in spatially extended data, and outline an appropriate approach should a spatially explicit analysis be considered necessary
Anatomic-electrophysiological correlations concerning the pathways for atrioventricular conduction.
The remarkable success of radiofrequency ablation in recent decades in curing atrioventricular nodal reentrant tachycardias has intensified efforts to provide a solid theoretical basis for understanding the mechanisms of atrioventricular transmission. These efforts, which were made by both anatomists and electrophysiologists, frequently resulted in seemingly controversial observations. Quantitatively and qualitatively, our understanding of the mysteries of propagation through the inhomogeneous and extremely complex atrioventricular conduction axis is much deeper than it was at the beginning of the past century. We must go back to the initial sources, nonetheless, in an attempt to provide a common ground for evaluating the morphological and electrophysiological principles of junctional arrhythmias. In this review, we provide an account of the initial descriptions, which still provide an appropriate foundation for interpreting recent electrophysiological findings
Origin, evolution and dynamic context of a Neoglacial lateral-frontal moraine at Austre Lovénbreen, Svalbard
Moraines marking the Neoglacial limits in Svalbard are commonly ice cored. Investigating the nature of this relict ice is important because it can aid our understanding of former glacier dynamics. This paper examines the composition of the lateral–frontal moraine associated with the Neoglacial limit at Austre Lovénbreen and assesses the likely geomorphological evolution. The moraine was investigated using ground-penetrating radar (GPR), with context being provided by structural mapping of the glacier based on an oblique aerial image from 1936 and vertical aerial imagery from 2003. Multiple up-glacier dipping reflectors and syncline structures are found in the GPR surveys. The reflectors are most clearly defined in lateral positions, where the moraine is substantially composed of ice. The frontal area of the moraine is dominantly composed of debris. The core of the lateral part of the moraine is likely to consist of stacked sequences of basal ice that have been deformed by strong longitudinal compression. The long term preservation potential of the ice-dominated lateral moraine is negligible, whereas the preservation of the debris-dominated frontal moraine is high. A glacier surface bulge, identified on the 1936 aerial imagery, provides evidence that Austre Lovénbreen has previously displayed surge activity, although it is highly unlikely to do so in the near future in its current state. This research shows the value of relict buried ice that is preserved in landforms to aiding our understanding of former glacier characteristics
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Role of Positron Emission Tomography in Imaging of Non-neurologic Disorders of the Head, Neck, and Teeth in Veterinary Medicine.
Positron Emission Tomography (PET) is an imaging technique that provides functional information, in addition to structural information obtained with computed tomography (CT). The most common application is cancer staging, using 18F-Fluorodeoxyglucose (18F-FDG), a radioactive analog of glucose. Although limited data are available in the veterinary literature, human studies have demonstrated benefit with the addition of PET both for assessment of the primary tumor and for detection of metastatic disease. 18F-FDG PET appears to be more accurate at detecting the margin of oral neoplasia, in particular for tumors arising from highly vascularized tissue, such as the lingual and laryngeal areas. 18F-FDG PET has a high sensitivity for the detection of lymph node metastasis, however the specificity is variable between studies. Tracers beyond 18F-FDG can also be used for oncology imaging. 18F-Fluoride (18F-NaF) is an excellent osseous tracer, useful in assessing bone involvement of primary tumors or osseous metastasis. Other specific tracers can be used to assess cell proliferation or hypoxia for tumor characterization. 18F-FDG is also an excellent tracer for detection of inflammation. Human studies have demonstrated its value for the assessment of periodontitis and dental implant infection. 18F-NaF has been used to assess disorders of the temporomandibular joint in the human literature, demonstrating good correlation with arthralgia and therapeutic outcome. Both 18F-NaF and 18F-FDG had good concordance with localization of cervical pain in people. PET will likely have a growing role in veterinary medicine not only for oncologic imaging but also for assessment of inflammation and pain
Tissue Tracking Imaging for Identifying the Origin of Idiopathic Ventricular Arrhythmias: A New Role of Cardiac Ultrasound in Electrophysiology
Several strategies for mapping ventricular outflow tract tachycardia have been reported as useful indices for differentiating between those originating from the right and the left side. Recently, tissue tracking imaging (TTI) has been demonstrated as a novel non-invasive modality for identifying the origin of outflow tract tachycardias. Tissue tracking imaging is an ultrasonographic technique that measures the myocardial motion amplitude towards the transducer in each region during systole, identifying regional myocardial displacement on the basis of myocardial velocities using color Doppler myocardial imaging principles. In this technique, the origin of the arrhythmia could be recognized as the site where the earliest color-coded signal (ECCS) appeared on the myocardium at the onset of the systole. In preliminary studies this modality was found to be useful in differentiating out flow tract ventricular tachycardias. ECCS was always found below or at the level of the pulmonary valve in all arrhythmias which could be ablated from the right ventricular outflow tract, while in those where the origin was above the pulmonary valve could be ablated from the left sinus of valsalva. These results indicate that TTI can provide detailed and accurate information on the arrhythmia origin of OT-VT and may be useful for differentiating between an OT-VT originating from the LV epicardium remote from the LSV and that from the LSV. Newer advances in echocardiographic technologies like high resolution, high frame rate real time three dimensional echocardiography with speckle tracking may further improve the precise localization of arrhythmias in the future
Nutritional status of young children with inherited blood disorders in western Kenya.
To determine the association between a range of inherited blood disorders and indicators of poor nutrition, we analyzed data from a population-based, cross-sectional survey of 882 children 6–35 months of age in western Kenya. Of children with valid measurements, 71.7% were anemic (hemoglobin < 11 g/dL), 19.1% had ferritin levels < 12 μg/L, and 30.9% had retinol binding protein (RBP) levels < 0.7 μmol/L. Unadjusted analyses showed that compared with normal children, homozygous α(+)-thalassemia individuals had a higher prevalence of anemia (82.3% versus 66.8%, P = 0.001), but a lower prevalence of low RBP (20.5% versus 31.4%, P = 0.024). In multivariable analysis, homozygous α(+)-thalassemia remained associated with anemia (adjusted odds ratio [aOR] = 1.8, P = 0.004) but not with low RBP (aOR = 0.6, P = 0.065). Among young Kenyan children, α(+)-thalassemia is associated with anemia, whereas G6PD deficiency, haptoglobin 2-2, and HbS are not; none of these blood disorders are associated with iron deficiency, vitamin A deficiency, or poor growth
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