169 research outputs found
The Health Impacts of Climate Change: A Study of Cholera in Tanzania
Increased temperatures and changes in patterns of rainfall as a result of climate change are widely recognized to entail serious consequences for human health, including the risk of diarrheal diseases. Indeed, there is strong evidence that temperature and rainfall patterns affect the disease pattern. This paper presents the first study that links the incidence of cholera to environmental and socioeconomic factors and uses that relationship to predict how climate change will affect the incidence of cholera. Specifically, the paper integrates historical data on temperature and rainfall with the burden of disease from cholera in Tanzania, and uses socioeconomic data to control for impacts of general development on the risk of cholera. Based on these results we estimate the number and costs of additional cholera cases and deaths that can be attributed to climate change by year 2030 in Tanzania. The analyses are based on primary data collected from the Ministry of Health, Tanzania, and the Tanzania Meteorological Agency. The result shows a significant relationship between cholera cases and temperature and predicts an increase in the initial risk ratio for cholera in Tanzania in the range of 23 to 51 percent for a 1 degree Celsius increase in annual mean temperature. The cost of reactive adaptation to cholera attributed to climate change impacts by year 2030 in Tanzania is projected to be in the range of 0.02 to 0.09 percent of GDP for the lower and upper bounds respectively. Total costs, including loss of lives are estimated in the range of 1.4 to 7.8 percent of GDP by year 2030. Lastly, costs of additional cholera cases and deaths attributed to climate change impacts in Tanzania by the year 2030 largely exceed the costs of preventive measures such as household chlorination.climate change,health impacts,adaptation costs,Tanzania
Postictal serotonin levels are associated with peri-ictal apnea.
ObjectiveTo determine the relationship between serum serotonin (5-HT) levels, ictal central apnea (ICA), and postconvulsive central apnea (PCCA) in epileptic seizures.MethodsWe prospectively evaluated video EEG, plethysmography, capillary oxygen saturation (SpO2), and ECG for 49 patients (49 seizures) enrolled in a multicenter study of sudden unexpected death in epilepsy (SUDEP). Postictal and interictal venous blood samples were collected after a clinical seizure for measurement of serum 5-HT levels. Seizures were classified according to the International League Against Epilepsy 2017 seizure classification. We analyzed seizures with and without ICA (n = 49) and generalized convulsive seizures (GCS) with and without PCCA (n = 27).ResultsPostictal serum 5-HT levels were increased over interictal levels for seizures without ICA (p = 0.01), compared to seizures with ICA (p = 0.21). In patients with GCS without PCCA, serum 5-HT levels were increased postictally compared to interictal levels (p < 0.001), but not in patients with seizures with PCCA (p = 0.22). Postictal minus interictal 5-HT levels also differed between the 2 groups with and without PCCA (p = 0.03). Increased heart rate was accompanied by increased serum 5-HT levels (postictal minus interictal) after seizures without PCCA (p = 0.03) compared to those with PCCA (p = 0.42).ConclusionsThe data suggest that significant seizure-related increases in serum 5-HT levels are associated with a lower incidence of seizure-related breathing dysfunction, and may reflect physiologic changes that confer a protective effect against deleterious phenomena leading to SUDEP. These results need to be confirmed with a larger sample size study
Environmental And Occupational Exposures And Amyotrophic Lateral Sclerosis In New England
Background: Recent data provide support for the concept that potentially modifiable exposures are responsible for sporadic amyotrophic lateral sclerosis (ALS). Objective: To evaluate environmental and occupational exposures as risk factors for sporadic ALS. Methods: We performed a case control study of ALS among residents of New England, USA. The analysis compared questionnaire responses from 295 patients with a confirmed ALS diagnosis to those of 225 controls without neurodegenerative illness. Results: Self-reported job-or hobby-related exposure to one or more chemicals, such as pesticides, solvents, or heavy metals, increased the risk of ALS (adjusted OR 2.51; 95% CI 1.64-3.89). Industries with a higher toxicant exposure potential (construction, manufacturing, mechanical, military, or painting) were associated with an elevated occupational risk (adjusted OR 3.95; 95% CI 2.04-8.30). We also identified increases in the risk of ALS associated with frequent participation in water sports, particularly waterskiing (adjusted OR 3.89; 95% C11.97-8.44). Occupation and waterskiing both retained independent statistical significance in a composite model containing age, gender, and smoking status. Conclusions: Our study contributes to a growing body of literature implicating occupational-and hobby-related toxicant exposures in ALS etiology. These epidemiologic study results also provide motivation for future evaluation of water-body-related risk factors. (C) 2017 S. Karger AG, Base
Analytical and computational study of magnetization switching in kinetic Ising systems with demagnetizing fields
An important aspect of real ferromagnetic particles is the demagnetizing
field resulting from magnetostatic dipole-dipole interaction, which causes
large particles to break up into domains. Sufficiently small particles,
however, remain single-domain in equilibrium. This makes such small particles
of particular interest as materials for high-density magnetic recording media.
In this paper we use analytic arguments and Monte Carlo simulations to study
the effect of the demagnetizing field on the dynamics of magnetization
switching in two-dimensional, single-domain, kinetic Ising systems. For systems
in the ``Stochastic Region,'' where magnetization switching is on average
effected by the nucleation and growth of fewer than two well-defined critical
droplets, the simulation results can be explained by the dynamics of a simple
model in which the free energy is a function only of magnetization. In the
``Multi-Droplet Region,'' a generalization of Avrami's Law involving a
magnetization-dependent effective magnetic field gives good agreement with our
simulations.Comment: 29 pages, REVTeX 3.0, 10 figures, 2 more figures by request.
Submitted Phys. Rev.
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