27 research outputs found
Recurrent madura foot without draining sinuses: a case report
Madura foot or mycetoma is a chronic granulomatous disease characterized by localized infection of subcutaneous tissues by actinomycetes or fungi. The recurrence rate for the disease if treated inadequately is very high. Recurrence presents with swelling and multiple discharging sinuses. This is an unusual presentation of the disease without discharging sinuses which is probable the first report of this kind in the literature. A 34 year old, male, presented with the painless, progressive swellings over right foot since 4 years. No sinuses or discharge could be found on skin surface. The postoperative recurrence rate is very high, and this can be local or distant at the regional lymph nodes. This could be due to the disease biology and behavior or inadequate surgical excision. Usually it presents with multiple sinus tracts, and granule. We reported a case with classical absence of sinus tracts in recurrent actinomycosis
Kappa distribution from particle correlations in non-equilibrium, steady-state plasmas
Kappa-distributed velocities in plasmas are common in a wide variety of
settings, from low-density to high-density plasmas. To date, they have been
found mainly in space plasmas, but are recently being considered also in the
modelling of laboratory plasmas. Despite being routinely employed, the origin
of the kappa distribution remains, to this day, unclear. For instance,
deviations from the Maxwell-Boltzmann distribution are sometimes regarded as a
signature of the non-additivity of the thermodynamic entropy, although there
are alternative frameworks such as superstatistics where such an assumption is
not needed. In this work we recover the kappa distribution for particle
velocities from the formalism of non-equilibrium steady-states, assuming only a
single requirement on the dependence between the kinetic energy of a test
particle and that of its immediate environment. Our results go beyond the
standard derivation based on superstatistics, as we do not require any
assumption about the existence of temperature or its statistical distribution,
instead obtaining them from the requirement on kinetic energies. All of this
suggests that this family of distributions may be more common than usually
assumed, widening its domain of application in particular to the description of
plasmas from fusion experiments. Furthermore, we show that a description of
kappa-distributed plasma is simpler in terms of features of the
superstatistical inverse temperature distribution rather than the traditional
parameters and the thermal velocity
Use of a plasma focus device to study pulsed x-ray effects on peripheral blood lymphocytes : Analysis of chromosome aberrations
X-ray pulses (full width at half maximum ∼ 90 ns, dose rate ∼ 107 Gy s−1) were used to irradiate the monolayer of peripheral blood mononucleated cells using the PF-2kJ kilojoule plasma focus device. Four different exposure conditions were evaluated using 5, 10, 20, and 40 pulses, with the mean dose measured by TLD-100 being 0.12 ± 0.02 mGy, 0.14 ± 0.03 mGy, 0.22 ± 0.06 mGy, and 0.47 ± 0.09 mGy, respectively. Cytogenetic analysis showed an increase in all types of chromosomal aberrations following exposure to x-ray pulses. The distribution of dicentrics and centric rings was overdispersed after 5, 10, 20, and 40 pulses. Additionally, after 20 and 40 pulses, the presence of tricentric chromosomes is detected. Chromosome aberration frequencies found in this study were always higher than the estimated frequencies of chromosome aberrations using published dose-effect curves for conventional radiation sources. The overdispersion observed, the elevated maximum relative biological effectiveness (RBEM) and the presence of tricentric chromosomes at the relatively low doses of exposure (<0.5 Gy) seem to indicate that low doses of pulsed x-rays of low energy show similar biological effects as those observed for high-LET radiation. X-ray pulses emitted by PF-2kJ were found to be more efficient in inducing chromosome aberrations, even more than α particles
Experimental measurements of high-energy photons in X-rays pulses emitted from a hundred joules plasma focus device and its interpretations
In the present work, efforts are made to identify the presence of high energy photons in X-rays pulses, emitted
from a hundred joules plasma focus device, PF-400J. Two different experiments were carried out, with the
insertion of a lead piece inside the hollow anode of PF-400J and without insertion of the lead piece. A pair of two
photomultiplier tubes (PMTs) was mounted in the axial direction and a similar pair of PMTs was mounted in the
radial direction, simultaneously. After establishing a correlation between two PMTs in each pair, one of the
PMTs in both directions was blocked by a rectangular slab of the lead of thickness ~17 mm. Linear attenuation
coefficient (LAC) of lead was estimated using the PMTs signals. Later, the X-rays energies were interpolated for
the estimated LAC values in both cases, with and without insertion of lead piece inside the hollow anode.
Interpolated energies reveal the presence of 0.55–0.85 MeV photons in the X-rays pulses in the axial direction,
while, in radial direction ranges 0.4–0.9 MeV, for the case without lead inserted inside the hollow anode.
Insertion of the lead inside the hollow anode does not change the X-rays energies significantly, nonetheless, it
increases X-rays repetition rate per hundred discharges. The presence of high energy photons in the X-rays pulses
indicates the existence of relativistic electrons. To explain it, induced electric and magnetic fields were estimated
using generalized Ohm’s law. We conclude that the electron acceleration mechanisms might not be the same in
the axial and radial directions.Indexación: Scopu
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Implications of Superstatistics for steady-state plasmas
Colissionless plasmas are non-extensive systems which, due to the long-range interaction between their components, are incapable of reaching thermal equilibrium, even in a steady state. These systems cannot, therefore, be described statistically by a single canonical distribution with well-defined inverse temperature β = 1/kBT and are commonly described via two alternative approaches: namely Tsallis statistics and Superstatistics. The use of Superstatistics in describing steady-state plasmas has been proposed by several authors, more recently Ourabah et al. In this work we study the consequences of this assumption of Superstatistics for steady-state plasmas. We explicitly show that only the ensembles characterized by the condition P(x|ρ) = ρ(H(x)) are consistent with a generalized definition of temperature introduced recently. We show how this formalism is employed in the case of plasma, considering interaction with external electromagnetic fields as well as between particles in the plasma. Our results clearly illustrate why low-energy particles tend to the Maxwellian distribution of velocities, while high-energy particles contribute to the long tails of the velocity distribution