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1.

Background

Although arctic lakes have responded sensitively to 20th-century climate change, it remains uncertain how these ecological transformations compare with alpine and montane-boreal counterparts over the same interval. Furthermore, it is unclear to what degree other forcings, including atmospheric deposition of anthropogenic reactive nitrogen (Nr), have participated in recent regime shifts. Diatom-based paleolimnological syntheses offer an effective tool for retrospective assessments of past and ongoing changes in remote lake ecosystems.

Methodology/Principal Findings

We synthesized 52 dated sediment diatom records from lakes in western North America and west Greenland, spanning broad latitudinal and altitudinal gradients, and representing alpine (n = 15), arctic (n = 20), and forested boreal-montane (n = 17) ecosystems. Diatom compositional turnover (β-diversity) during the 20th century was estimated using Detrended Canonical Correspondence Analysis (DCCA) for each site and compared, for cores with sufficiently robust chronologies, to both the 19th century and the prior ∼250 years (Little Ice Age). For both arctic and alpine lakes, β-diversity during the 20th century is significantly greater than the previous 350 years, and increases with both latitude and altitude. Because no correlation is apparent between 20th-century diatom β-diversity and any single physical or limnological parameter (including lake and catchment area, maximum depth, pH, conductivity, [NO3 ], modeled Nr deposition, ambient summer and winter air temperatures, and modeled temperature trends 1948–2008), we used Principal Components Analysis (PCA) to summarize the amplitude of recent changes in relationship to lake pH, lake:catchment area ratio, modeled Nr deposition, and recent temperature trends.

Conclusions/Significance

The ecological responses of remote lakes to post-industrial environmental changes are complex. However, two regions reveal concentrations of sites with elevated 20th-century diatom β-diversity: the Arctic where temperatures are increasing most rapidly, and mid-latitude alpine lakes impacted by high Nr deposition rates. We predict that remote lakes will continue to shift towards new ecological states in the Anthropocene, particularly in regions where these two forcings begin to intersect geographically.  相似文献   

2.
Large-scale climate history of the past millennium reconstructed solely from tree-ring data is prone to underestimate the amplitude of low-frequency variability. In this paper, we aimed at solving this problem by utilizing a novel method termed “MDVM”, which was a combination of the ensemble empirical mode decomposition (EEMD) and variance matching techniques. We compiled a set of 211 tree-ring records from the extratropical Northern Hemisphere (30–90°N) in an effort to develop a new reconstruction of the annual mean temperature by the MDVM method. Among these dataset, a number of 126 records were screened out to reconstruct temperature variability longer than decadal scale for the period 850–2000 AD. The MDVM reconstruction depicted significant low-frequency variability in the past millennium with evident Medieval Warm Period (MWP) over the interval 950–1150 AD and pronounced Little Ice Age (LIA) cumulating in 1450–1850 AD. In the context of 1150-year reconstruction, the accelerating warming in 20th century was likely unprecedented, and the coldest decades appeared in the 1640s, 1600s and 1580s, whereas the warmest decades occurred in the 1990s, 1940s and 1930s. Additionally, the MDVM reconstruction covaried broadly with changes in natural radiative forcing, and especially showed distinct footprints of multiple volcanic eruptions in the last millennium. Comparisons of our results with previous reconstructions and model simulations showed the efficiency of the MDVM method on capturing low-frequency variability, particularly much colder signals of the LIA relative to the reference period. Our results demonstrated that the MDVM method has advantages in studying large-scale and low-frequency climate signals using pure tree-ring data.  相似文献   

3.

Background

There is limited evidence for the impacts of meteorological changes on asthma hospital admissions in adults in Shanghai, China.

Objectives

To quantitatively evaluate the short-term effects of daily mean temperature on asthma hospital admissions.

Methods

Daily hospital admissions for asthma and daily mean temperatures between January 2005 and December 2012 were analyzed. After controlling for secular and seasonal trends, weather, air pollution and other confounding factors, a Poisson generalized additive model (GAM) combined with a distributed lag non-linear model were used to explore the associations between temperature and hospital admissions for asthma.

Results

During the study periods, there were 15,678 hospital admissions for asthma by residents of Shanghai, an average 5.6 per day. Pearson correlation analysis found a significant negative correlation (r = −0.174, P<0.001) between asthma hospitalizations and daily mean temperature (DMT). The DMT effect on asthma increased below the median DMT, with lower temperatures associated with a higher risk of hospital admission for asthma. Generally, the cold effect appeared to be relatively acute, with duration lasting several weeks, while the hot effect was short-term. The relative risk of asthma hospital admissions associated with cold temperature (the 25th percentile of temperature relative to the median temperature) was 1.20 (95% confidence interval [CI], 1.01∼1.41) at lag0-14. However, warmer temperatures were not associated with asthma hospital admissions.

Conclusions

Cold temperatures may trigger asthmatic attacks. Effective strategies are needed to protect populations at risk from the effects of cold.  相似文献   

4.

Background

The new field of paleomicrobiology allows past outbreaks to be identified by testing dental pulp of human remains with PCR.

Methods

We identified a mass grave in Douai, France dating from the early XVIIIth century. This city was besieged during the European war of Spanish succession. We tested dental pulp from 1192 teeth (including 40 from Douai) by quantitative PCR (qPCR) for R. prowazekii and B. quintana. We also used ultra-sensitive suicide PCR to detect R. prowazekii and genotyped positive samples.

Results and Discussion

In the Douai remains, we identified one case of B. quintana infection (by qPCR) and R. prowazekii (by suicide PCR) in 6/21 individuals (29%). The R. prowazekii was genotype B, a genotype previously found in a Spanish isolate obtained in the first part of the XXth century.

Conclusion

Louse-borne outbreaks were raging during the XVIIIth century; our results support the hypothesis that typhus was imported into Europe by Spanish soldiers from America.  相似文献   

5.

Background

The synergetic effects of recent rising atmospheric CO2 and temperature are expected to favor tree growth in boreal and temperate forests. However, recent dendrochronological studies have shown site-specific unprecedented growth enhancements or declines. The question of whether either of these trends is caused by changes in the atmosphere remains unanswered because dendrochronology alone has not been able to clarify the physiological basis of such trends.

Methodology/Principal Findings

Here we combined standard dendrochronological methods with carbon isotopic analysis to investigate whether atmospheric changes enhanced water use efficiency (WUE) and growth of two deciduous and two coniferous tree species along a 9° latitudinal gradient across temperate and boreal forests in Ontario, Canada. Our results show that although trees have had around 53% increases in WUE over the past century, growth decline (measured as a decrease in basal area increment – BAI) has been the prevalent response in recent decades irrespective of species identity and latitude. Since the 1950s, tree BAI was predominantly negatively correlated with warmer climates and/or positively correlated with precipitation, suggesting warming induced water stress. However, where growth declines were not explained by climate, WUE and BAI were linearly and positively correlated, showing that declines are not always attributable to warming induced stress and additional stressors may exist.

Conclusions

Our results show an unexpected widespread tree growth decline in temperate and boreal forests due to warming induced stress but are also suggestive of additional stressors. Rising atmospheric CO2 levels during the past century resulted in consistent increases in water use efficiency, but this did not prevent growth decline. These findings challenge current predictions of increasing terrestrial carbon stocks under climate change scenarios.  相似文献   

6.

Background

Adult metabolic syndrome may originate in part during fetal or early life. This study was designed to investigate the effects of prenatal exposure to lipopolysaccharide (LPS) on adipose development and local renin-angiotensin system (RAS) activation in rat offspring.

Methods

Pregnant rats were randomly divided into three groups (n = 8 in each), including an NS group (pregnant rats were only treated with 0.5 ml normal saline from the 8th to the 14th day of gestation); an LPS group (pregnant rats were injected intraperitoneally with 0.79 mg/kg LPS on the 8th, 10th and 12th days of pregnancy); and an LPS+pyrrolidine dithiocarbamate (PDTC) group (identical to the LPS group except that 100 mg/kg PDTC was administered from the 8th to the 14th day of gestation).

Results

Prenatal exposure to LPS resulted in increased blood pressure, adipose coefficient and body weight in rat offspring. Specifically, during the infancy of the offspring rats, the LPS stimulus promoted the differentiation of adipose cells, diminishing their diameters and proportions while simultaneously increasing cell number. In contrast, once the rats were grown, adipose cell differentiation was inhibited, and the diameters and proportions of the cells were increased. Moreover, each component of the RAS was changed and was shown to be activated. PDTC, an inhibitor of NF-κB, could reverse the influence of the stimulus during pregnancy.

Conclusion

Prenatal exposure to LPS in rats results in increased blood pressure, adipose coefficient, body weight and activation of adipose RAS in offspring.  相似文献   

7.

Background

Effective surveillance for infectious diseases is an essential component of public health. There are few studies estimating the cost-effectiveness of starting or improving disease surveillance. We present a cost-effectiveness analysis the Integrated Disease Surveillance and Response (IDSR) strategy in Africa.

Methodology/Principal Findings

To assess the impact of the IDSR in Africa, we used pre- and post- IDSR meningococcal meningitis surveillance data from Burkina Faso (1996–2002 and 2003–2007). IDSR implementation was correlated with a median reduction of 2 weeks to peak of outbreaks (25th percentile 1 week; 75th percentile 4 weeks). IDSR was also correlated with a reduction of 43 meningitis cases per 100,000 (25th–40: 75th-129). Assuming the correlations between reductions in time to peak of outbreaks and cases are related, the cost-effectiveness of IDSR was $23 per case averted (25th-$30; 75th - cost saving), and $98 per meningitis-related death averted (25th-$140: 75th – cost saving).

Conclusions/Significance

We cannot absolutely claim that the measured differences were due to IDSR. We believe, however, that it is reasonable to claim that IDSR can improve the cost-effectiveness of public health surveillance.  相似文献   

8.

Background

In response to India''s growing tobacco epidemic, strategies are needed to decrease tobacco use among Indian youth, particularly among those who are economically disadvantaged. The objective of this study was to assess the effectiveness of a school-based life-skills tobacco control program for youth of low socio-economic status in Mumbai and the surrounding state of Maharashtra. We hypothesized that compared to youth in control schools, youth exposed to the program would have greater knowledge of effects of tobacco use; be more likely to take action to prevent others from using tobacco; demonstrate more positive life skills and attitudes; and be less likely to report tobacco use.

Methods/Findings

Using a quasi-experimental design, we assessed program effectiveness by comparing 8th and 9th grade students in intervention schools to 8th grade students in comparable schools that did not receive the program. Across all schools, 1851 students completed a survey that assessed core program components in early 2010. The program consisted of activities focused on building awareness about the hazards of tobacco, developing life skills, and advocacy development. The primary outcome measure was self-reported tobacco use in the last 30 days.Findings indicate that 4.1% of 8th grade intervention students (OR = 0.51) and 3.6% of 9th grade intervention students (OR = 0.33) reported using tobacco at least once in the last 30 days, compared to 8.7% of students in the control schools. Intervention group students were also significantly more knowledgeable about tobacco and related legislation, reported more efforts to prevent tobacco use among others, and reported stronger life skills and self-efficacy than students in control schools. Limitations to the study include schools not being randomly assigned to condition and tobacco use being measured by self-report.

Conclusions

This program represents an effective model of school-based tobacco use prevention that low-income schools in India and other low- and middle-income countries can replicate.  相似文献   

9.

Objectives

Our aim was to establish whether there is an interconnection between the compositional development of the gut microbiota and the amount of fussing and crying in early infancy.

Methods

Behavioral patterns of 89 infants during the 7th and 12th week of life were recorded in parental diaries. Total distress was defined as the sum of daily amounts of crying and fussing. Infants'' gut microbiota profiles were investigated by several molecular assays during the first six months of life.

Results

The median (range) duration of total distress among the infants was 106 (0–478) minutes a day during the 7th and 58 (0–448) minutes a day during the 12th week. The proportion of Bifidobacterium counts to total bacterial counts was inversely associated with the amount of crying and fussing during the first 3 months of life (p = 0.03), although the number of Bifidobacterium breve was positively associated with total distress (p = 0.02). The frequency of Lactobacillus spp. at the age of 3 weeks was inversely associated with total infant distress during the 7th week of life (p = 0.02).

Conclusions

Bifidobacterium and Lactobacillus appear to protect against crying and fussing. Identification of specific strains with optimal protective properties would benefit at-risk infants.  相似文献   

10.

Background

High radiation doses employed in cardiac imaging may increase cancer frequency in exposed patients after decades. The aim of this study was to evaluate the relative trends in medical radiation exposure in a population hospitalized for cardiovascular disease.

Methods and Results

An observational single-center study was conducted to examine 16,431 consecutive patients with heart disease admitted to the Italian National Research Council Institute of Clinical Physiology between January 1970 and December 2009. In all patients, the cumulative estimated effective dose was obtained from data mining of electronic records of hospital admissions, adopting the effective dose typical values of the American Heart Association 2009 statement and Mettler’s 2008 catalog of doses. Cumulative estimated effective dose per patient in the last 5 years was 22 (12–42) mSv (median, 25th–75th percentiles), with higher values in ischemic heart disease (IHD), 37 (20–59) vs non-IHD, 13 (8–22) mSv, p<0.001. Trends in radiation exposure showed a steady increase in IHD and a flat trend in non-IHD patients, with variation from 1970–74 to 2005–2009 of +155% for IHD (p<0.001) and −1% in non-IHD (NS). The relative contribution of different imaging techniques was remodeled over time, with nuclear cardiology dominating in 1970s (23% of individual exposure) and invasive fluoroscopy in the last decade (90% of individual exposure).

Conclusion

A progressive increase in cumulative estimated effective dose is observed in hospitalized IHD patients. The growing medical radiation exposure may encourage a more careful justification policy regarding ionizing imaging in cardiology patients applying the two main principles of radiation protection: appropriate justification for ordering and performing each procedure, and careful optimization of the radiation dose used during each procedure.  相似文献   

11.

Background

Human hearing develops progressively during the last trimester of gestation. Near-term fetuses can discriminate acoustic features, such as frequencies and spectra, and process complex auditory streams. Fetal and neonatal studies show that they can remember frequently recurring sounds. However, existing data can only show retention intervals up to several days after birth.

Methodology/Principal Findings

Here we show that auditory memories can last at least six weeks. Experimental fetuses were given precisely controlled exposure to a descending piano melody twice daily during the 35th, 36th, and 37th weeks of gestation. Six weeks later we assessed the cardiac responses of 25 exposed infants and 25 naive control infants, while in quiet sleep, to the descending melody and to an ascending control piano melody. The melodies had precisely inverse contours, but similar spectra, identical duration, tempo and rhythm, thus, almost identical amplitude envelopes. All infants displayed a significant heart rate change. In exposed infants, the descending melody evoked a cardiac deceleration that was twice larger than the decelerations elicited by the ascending melody and by both melodies in control infants.

Conclusions/Significance

Thus, 3-weeks of prenatal exposure to a specific melodic contour affects infants ‘auditory processing’ or perception, i.e., impacts the autonomic nervous system at least six weeks later, when infants are 1-month old. Our results extend the retention interval over which a prenatally acquired memory of a specific sound stream can be observed from 3–4 days to six weeks. The long-term memory for the descending melody is interpreted in terms of enduring neurophysiological tuning and its significance for the developmental psychobiology of attention and perception, including early speech perception, is discussed.  相似文献   

12.

Objective

The purpose of this study was to investigate the histological and morphological changes in the first two postoperative weeks on a rat intraperitoneal adhesion model induced by duodenum clamping trauma.

Method

The rat model of postoperative intraperitoneal adhesions was established in 48 male Wistar rats by laparotomy, followed by the duodenum clamping trauma. Rats were sacrificed respectively on 1st, 3rd, 5th, 7th and 14th day after the operation. The control rats were sacrificed immediately after the operation (0 day). Then the intraperitoneal adhesions were assessed macroscopically. Histopathology and immunohistochemistry were performed to evaluate the fibrosis, inflammatory responses, neovascularization, and cells infiltration in adhesion tissues. In addition, the changes of the mesothelium covering the surgical sites were examined by scanning electron microscopy.

Results

Our study revealed that duodenum clamping trauma induced by mosquito hemostat can result in significant postoperative intraperitoneal adhesions formation. The extent and tenacity of intraperitoneal adhesions reached their peaks on 3rd and 5th days, respectively. Histopathological examination showed that all rats developed inflammatory responses at the clamped sites of duodenum, which was most prominent on 1st day; the scores of fibrosis and vascular proliferation increased slowly from 3rd to 5th day. Myofibroblasts proliferated significantly in the adhesion tissues from 3rd day, which were examined by immunohistochemical method. And the mesothelium covering the surgical sites and the adhesion tissues healed on 7th day.

Conclusion

This study suggests that clamping trauma to the duodenum can result in significant postoperative intraperitoneal adhesions formation, which represents an ideal rat model for intraperitoneal adhesions research and prevention. And myofibroblasts may play an important role in the forming process of intraperitoneal adhesions.  相似文献   

13.

Background and Aims

In a future warmer subarctic climate, the soil temperatures experienced by dispersed seeds are likely to increase during summer but may decrease during winter due to expected changes in snow depth, duration and quality. Because little is known about the dormancy-breaking and germination requirements of subarctic species, how warming may influence the timing and level of germination in these species was examined.

Methods

Under controlled conditions, how colder winter and warmer summer soil temperatures influenced germination was tested in 23 subarctic species. The cold stratification and warm incubation temperatures were derived from real soil temperature measurements in subarctic tundra and the temperatures were gradually changed over time to simulate different months of the year.

Key Results

Moderate summer warming (+2·5 °C) substantially accelerated germination in all but four species but did not affect germination percentages. Optimum germination temperatures (20/10°C) further decreased germination time and increased germination percentages in three species. Colder winter soil temperatures delayed the germination in ten species and decreased the germination percentage in four species, whereas the opposite was found in Silene acaulis. In most species, the combined effect of a reduced snow cover and summer warming resulted in earlier germination and thus a longer first growing season, which improves the chance of seedling survival. In particular the recruitment of (dwarf) shrubs (Vaccinium myrtillus, V. vitis-idaea, Betula nana), trees (Alnus incana, Betula pubescens) and grasses (Calamagrostis lapponica, C. purpurea) is likely to benefit from a warmer subarctic climate.

Conclusions

Seedling establishment is expected to improve in a future warmer subarctic climate, mainly by considerably earlier germination. The magnitudes of the responses are species-specific, which should be taken into account when modelling population growth and migration of subarctic species.Key words: Climate change, cold stratification, dwarf shrubs, germination percentage, incubation temperature, mean germination time, seedling establishment, seeds, Silene, subarctic species, Vaccinium, warming  相似文献   

14.

Objectives

We aimed to analyze the CT findings of ground-glass opacity nodules diagnosed pathologically as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma in order to investigate whether quantitative CT parameters enable distinction of invasive adenocarcinoma from pre-invasive or minimally invasive adenocarcinoma.

Methods

We reviewed CT images and pathologic specimens from 191 resected ground-glass opacity nodules with little or no solid component at CT. Nodule size, volume, density, mass, skewness/kurtosis, and CT attenuation values at the 2.5th–97.5th percentiles on histogram, and texture parameters (uniformity and entropy) were assessed from CT datasets.

Results

Of 191 tumors, 38 were AISs (20%), 61 were MIAs (32%), and 92 (48%) were invasive adenocarcinomas. Multivariate logistic regression analysis helped identify the 75th percentile CT attenuation value (P = 0.04) and entropy (P<0.01) as independent predictors for invasive adenocarcinoma, with an area under the receiver operating characteristic curve of 0.780.

Conclusion

Quantitative analysis of preoperative CT imaging metrics can help distinguish invasive adenocarcinoma from pre-invasive or minimally invasive adenocarcinoma.  相似文献   

15.
EJ Mmbaga  F Leonard  GH Leyna 《PloS one》2012,7(7):e41700

Purpose

To determine the incidence and predictors of adolescent’s early sexual debut after three decades of HIV interventions in Tanzania.

Methods

In a cross-section study of adolescents aged 16–19 residing in Morogoro Municipality, information on socio-demographic, parental-and-peer communication, and sexual behaviors were collected. Cox-regression analysis was used to examine predictors of time to sexual debut.

Results

A total of 316 adolescents with mean age of 17.5±0.9 were recruited. Half (48.7%) of adolescent were sexually active with mean age at sexual debut of 14.6±2.3. Of these, 57.8% had sex before their 15th birthday with incidence of early sexual debut of 17.4/1000 person-years at risk. Adolescent family characteristics, peer pressure, alcohol use, parental and peer communication were key predictors of early sexual debut.

Conclusion

Parental and peer communication strategies works calling for efforts to increase its scope to reach all adolescents alongside promoting family stability and reducing adolescent alcohol consumption.  相似文献   

16.

Background

Quantile regression, a robust semi-parametric approach, was used to examine the impact of gestational diabetes mellitus (GDM) across birthweight quantiles with a focus on maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG).

Methods

Using linked birth certificate, inpatient hospital and prenatal claims data we examined live singleton births to non-Hispanic white (NHW, 135,119) and non-Hispanic black (NHB, 76,675) women in South Carolina who delivered 28–44 weeks gestation in 2004–2008.

Results

At a maternal BMI of 30 kg/m2 at the 90th quantile of birthweight, exposure to GDM was associated with birthweights 84 grams (95% CI 57, 112) higher in NHW and 132 grams (95% CI: 104, 161) higher in NHB. Results at the 50th quantile were 34 grams (95% CI: 17, 51) and 78 grams (95% CI: 56, 100), respectively. At a maternal GWG of 13.5 kg at the 90th quantile of birthweight, exposure to GDM was associated with birthweights 83 grams (95% CI: 57, 109) higher in NHW and 135 grams (95% CI: 103, 167) higher in NHB. Results at the 50th quantile were 55 grams (95% CI: 40, 71) and 69 grams (95% CI: 46, 92), respectively.

Summary

Our findings indicate that GDM, maternal prepregnancy BMI and GWG increase birthweight more in NHW and NHB infants who are already at the greatest risk of macrosomia or being large for gestational age (LGA), that is those at the 90th rather than the median of the birthweight distribution.  相似文献   

17.

Background

Considerable conceptual and operational complexities related to service quality measurements and variability in delivery contexts of scaled-up medical male circumcision, pose real challenges to monitoring implementation of quality and safety. Clarifying latent factors of the quality instruments can enhance contextual applicability and the likelihood that observed service outcomes are appropriately assessed.

Objective

To explore factors underlying SYMMACS service quality assessment tool (adopted from the WHO VMMC quality toolkit) and; determine service quality performance using composite quality index derived from the latent factors.

Study design

Using a comparative process evaluation of Voluntary Medical Male Circumcision Scale-Up in Kenya site level data was collected among health facilities providing VMMC over two years. Systematic Monitoring of the Medical Male Circumcision Scale-Up quality instrument was used to assess availability of guidelines, supplies and equipment, infection control, and continuity of care services. Exploratory factor analysis was performed to clarify quality structure.

Results

Fifty four items and 246 responses were analyzed. Based on Eigenvalue >1.00 cut-off, factors 1, 2 & 3 were retained each respectively having eigenvalues of 5.78; 4.29; 2.99. These cumulatively accounted for 29.1% of the total variance (12.9%; 9.5%; 6.7%) with final communality estimates being 13.06. Using a cut-off factor loading value of ≥0.4, fifteen items loading on factor 1, five on factor 2 and one on factor 3 were retained. Factor 1closely relates to preparedness to deliver safe male circumcisions while factor two depicts skilled task performance and compliance with protocols. Of the 28 facilities, 32% attained between 90th and 95th percentile (excellent); 45% between 50th and 75th percentiles (average) and 14.3% below 25th percentile (poor).

Conclusion

the service quality assessment instrument may be simplified to have nearly 20 items that relate more closely to service outcomes. Ranking of facilities and circumcision procedure using a composite index based on these items indicates that majority performed above average.  相似文献   

18.

Introduction

Altered thyroid status exerts a major effect on the heart. Individuals with hypo- or hyperthyroidism showed various changes in electrocardiograms. However, little is known about how variations in thyroid hormone levels within the normal range affect electrical activities of the heart in the general population.

Methods and Results

We conducted a cross-sectional analysis of 5,990 men and women from the Third National Health and Nutrition Examination Survey. Serum total T4 was measured by immunoassay and TSH was measured by chemiluminescent assay. We categorized T4 and TSH into 7 groups with cut-offs at the 5th, 20th, 40th, 60th, 80th, and 95th percentiles of the weighted population distribution. Electrocardiographic parameters were measured from the standard 12-lead electrocardiogram. We found a positive linear association between serum total T4 level and heart rate in men, and a U-shape association between T4 and PR interval in men and women. TSH level was positively associated with QRS interval in men, while a U-shape association between TSH and QRS was observed in women. No clear graded association between thyroid hormones and corrected QT or JT was found, except that men in the highest category of T4 levels appeared to have longer corrected QT and JT, and men in the lowest category of T4 appeared to have shorter corrected QT and JT.

Conclusions

Variation in thyroid hormone levels in the general population, even within the normal range, was associated with various ECG changes.  相似文献   

19.

Objectives

There is no agreed-upon definition for severe obesity (Sev-OB) in children. We compared estimates of Sev-OB as defined by different cut-points of body mass index (BMI) from the Centers for Disease Control and Prevention (CDC) or the World Health Organization (WHO) curves and the ability of each set of cut-points to screen for the presence of cardiometabolic risk factors.

Research Design and Methods

Cross-sectional, multicenter study involving 3,340 overweight/obese young subjects. Sev-OB was defined as BMI ≥99th percentile or ≥1.2 times the 95th percentile of the CDC or the WHO curves. High blood pressure, hypertriglyceridemia, low High Density Lipoprotein -cholesterol and impaired fasting glucose were considered as cardiometabolic risk factors.

Results

The estimated prevalence of Sev-OB varied widely between the two reference systems. Either using the cut-point ≥99th percentile or ≥1.2 times the 95th percentile, less children were defined as Sev-OB by CDC than WHO (46.8 vs. 89.5%, and 63.3 vs. 80.4%, respectively p<0.001). The CDC 99th percentile had lower sensitivity (58.5 vs 94.2), higher specificity (57.6 vs 12.3) and higher positive predictive value (34.4 vs 28.9) than WHO in identifying obese children with ≥2 cardiometabolic risk factors. These differences were mitigated using the 1.2 times the 95th percentile (sensitivity 73.9 vs. 88.1; specificity 40.7 vs. 22.5; positive predictive value 32.1 vs. 30.1). Substantial agreement between growth curves was found using the 1.2 times the 95th percentile, in particular in children ≤10 years.

Conclusions

Estimates of Sev-OB and cardiometabolic risk as defined by different cut-points of BMI are influenced from the reference systems used. The 1.2 times the 95th percentile of BMI of either CDC or WHO standard has a discriminatory advantage over the 99th percentile for identifying severely obese children at increased cardiometabolic risk, particularly under 10 years of age.  相似文献   

20.

Background

This year, Brazil will host about 600,000 foreign visitors during the 2014 FIFA World Cup. The concern of possible dengue transmission during this event has been raised given the high transmission rates reported in the past by this country.

Methodology/Principal Findings

We used dengue incidence rates reported by each host city during previous years (2001–2013) to estimate the risk of dengue during the World Cup for tourists and teams. Two statistical models were used: a percentile rank (PR) and an Empirical Bayes (EB) model. Expected IR''s during the games were generally low (<10/100,000) but predictions varied across locations and between models. Based on current ticket allocations, the mean number of expected symptomatic dengue cases ranged from 26 (PR, 10th–100th percentile: 5–334 cases) to 59 (EB, 95% credible interval: 30–77 cases) among foreign tourists but none are expected among teams. These numbers will highly depend on actual travel schedules and dengue immunity among visitors. Sensitivity analysis for both models indicated that the expected number of cases could be as low as 4 or 5 with 100,000 visitors and as high as 38 or 70 with 800,000 visitors (PR and EB, respectively).

Conclusion/Significance

The risk of dengue among tourists during the World Cup is expected to be small due to immunity among the Brazil host population provided by last year''s epidemic with the same DENV serotypes. Quantitative risk estimates by different groups and methodologies should be made routinely for mass gathering events.  相似文献   

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