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1.
Bibliometrics are a set of methods, which can be used to analyze academic literature quantitatively and its changes over time. The objectives of this study were 1) to evaluate trends related to academic performance of dental journals from 2003 to 2012 using bibliometric indices, and 2) monitor the changes of the five dental journals with the highest and lowest impact factor (IF) published in 2003. Data for the subject category "Dentistry, Oral Surgery & Medicine" was retrieved from the Journal Citation Reports (JCR) published from 2003 to 2012. Linear regressions analysis was used to determine statistical trends over the years with each bibliometric indicator as the dependent variable and the JCR year as the predictor variable. Statistically significant rise in the total number of dental journals, the number of all articles with the steepest rise observed for research articles, the number of citations and the aggregate IF was observed from 2003 to 2012. The analysis of the five top and five bottom-tire dental journals revealed a rise in IF however, with a wide variation in relation to the magnitude of this rise. Although the IF of the top five journals remained relatively constant, the percentile ranks of the four lowest ranking journals in 2003 increased significantly with the sharpest rise being noted for the British Journal of Oral & Maxillofacial Surgery. This study revealed significant growth of dental literature in absolute terms, as well as upward trends for most of the citation-based bibliometric indices from 2003 to 2012.  相似文献   

2.
The long-term variations in blood biomarkers and weight–size characteristics of the round goby, Neogobius melanostomus (Pallas, 1814), have been studied in specimens collected from two sites of the southwestern Sea of Azov. The fish from catches of 2011–2012 showed a decrease in the size and weight parameters and an increase in the antioxidant enzyme activities and the level of oxidized serum proteins compared to the values in the fish caught in 2003. The ecological causes of the observed differences and the possibility of using the studied fish blood biomarkers in programs of monitoring the marine coastal waters are discussed.  相似文献   

3.
BackgroundDengue infections are on the rise in Sri Lanka and are spreading to all areas in the country. Here, we discuss the changes in dengue epidemiology in Sri Lanka in relation to changes in age distribution, changes in seroprevalence rates over time, and possible reasons contributing to such changes.Methods and findingsAlthough the incidence of dengue increased 20-fold from the year 2000 to 2012 and a further 3-fold from 2012 to 2019, this increase is not reflected in a similar increase in the age-stratified seropositivity rates for dengue. For instance, the annual seroconversion rates were 0.76% in 2013 and 0.91% in 2017. The annual seroconversion rates in the 6 to 17 age group were 1.5% per year in 2003, 3.9% in 2013, and 4.1% in 2017. In addition, although a 13-fold increase in dengue was seen in those who were <19 years of age, a 52.4-fold increase was seen in the 40- to 59-year age group. The case fatality rates (CFRs) have similarly changed, with 61.8% of deaths occurring in those <19 years of age in the year 2000, while in 2012 to 2018, the highest CFR were seen in those who were aged 20 to 39 years. Although there has been a marked increase in the number of cases, the vector densities did not change during a 4-year period. The proportion of adult individuals experiencing a secondary dengue infection has also remained between 65% and 75% between the years 2004 and 2018.ConclusionsA change in the ratio of symptomatic to asymptomatic infections can give rise to changes in the reported incidence of dengue. In order to take an appropriate policy decision in dengue control activities, it would be important to study the changes in virus serotypes, vector dispersion, and densities. Further, the contribution of the rise in metabolic diseases to an increase in the symptomatic as well as more severe infections due to dengue is explored.  相似文献   

4.
The peculiarities of the distribution of the freshwater ichthyofauna, bottom sediments and conditions at the spawning grounds, and the egg survivability rate of Oncorhynchus gorbuscha were studied in 2003?2012 in a typical salmon river on Sakhalin Island (Goluboi Ruchei brook, Aniva Bay, southern Sakhalin). The sites characterized by the highest survivability rate of the embryos of the pink salmon are inhabited by the freshwater fish community where the juveniles of masu salmon O. masu and whitespotted char Salvelinus leucomaenis dominate. The lengthway bed slope at this site is steeper compared to the sites with lower survivability rates (0.010?0.020 vs. 0.004?0.020?). The maximal positive correlation of the egg survivability rate to the flow velocity of the underflow has been registered for the depth of 30?40 cm, and the maximal negative correlation of the egg survivability rate has been registered to the bottom sediment temperature.  相似文献   

5.
黑龙江流域积雪覆盖时空变化遥感监测   总被引:1,自引:0,他引:1  
利用MODIS双星数据对黑龙江流域2003—2012年的积雪覆盖面积进行提取和验证,然后基于合成的数据分析研究区积雪覆盖面积的季节和年际变化.结果表明: 双星合成降低了云的影响,总体精度>91%,可以满足分析和研究需求.研究期间,黑龙江流域积雪覆盖面积存在显著的季节变化,7、8月的积雪最少,几乎为零,1月积雪覆盖面积最大,占流域的80%以上.2003—2004、2009—2010年冬季积雪覆盖面积较高(>180×104 km2),2011年冬季最大积雪覆盖面积较低(150×104 km2).积雪覆盖的年际变化与年平均气温和平均降水量的波动存在一定的对应关系:积雪覆盖面积较低年份对应的年降水量较少、平均气温较高,反之亦然.2003—2012年,研究区5、6月的积雪覆盖面积呈减少趋势,降水量增加和气温的升高与积雪覆盖面积减少紧密相连.  相似文献   

6.
The results of virological examination of adult sockeye salmon Oncorhynchus nerka in Lake Nachikinskoe from 2003 to 2008 demonstrated high values of prevalence of the infectious hematopoietic necrosis virus (IHNV) in the fish population (up to 100%). In the studied water reservoir there are optimal conditions for the development and revealing of the epizootic of infectious hematopoietic necrosis (IHN). In Lake Nachikinskoe, two natural epizootics of IHN in juvenile sockeye salmon were recorded in 2003 and 2006. The tendencies for change of prevalence of IHNV by years were analyzed, and their relation to the numbers of adult sockeye salmon at the spawning grounds of Lake Nachikinskoe was determined. The correlation of IHNV prevalence with the numbers of adult sockeye salmon in the studied water reservoir is direct but insignificant (r s = 0.695, p < 0.05). It was shown that the epizootic of 2003 could affect the fact that fish return in 2007 and 2008 was minimum for the considered time interval while the numbers of their parents were, on the other hand, very high.  相似文献   

7.
The former Soviet Union (USSR) and the USA were the first countries to introduce standards limiting exposure to radiofrequency (RF) fields. However, the exposure limits in the USSR standards were always much lower than those in the USA and other countries. The objective of this article is to provide a history of the development of the Soviet and Russian RF standards. In addition, we summarize the scientific evidence used to develop the original USSR RF and subsequent Russian public health standards, as well as the mobile telecommunications standard published in 2003, but we do not critique them. We also describe the protective approaches used by the Soviet and Russian scientists for setting their limits. A translation of the papers of the key studies used to develop their standards is available in the online version of this publication. Bioelectromagnetics 33:623–633, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

8.
To understand the geographic distribution of visceral leishmaniasis (VL) in the state of Mato Grosso do Sul (MS), Brazil, both the climatic niches of Lutzomyia longipalpis and VL cases were analysed. Distributional data were obtained from 55 of the 79 counties of MS between 2003-2012. Ecological niche models (ENM) of Lu. longipalpis and VL cases were produced using the maximum entropy algorithm based on eight climatic variables. Lu. longipalpis showed a wide distribution in MS. The highest climatic suitability for Lu. longipalpis was observed in southern MS. Temperature seasonality and annual mean precipitation were the variables that most influenced these models. Two areas of high climatic suitability for the occurrence of VL cases were predicted: one near Aquidauana and another encompassing several municipalities in the southeast region of MS. As expected, a large overlap between the models for Lu. longipalpis and VL cases was detected. Northern and northwestern areas of MS were suitable for the occurrence of cases, but did not show high climatic suitability for Lu. longipalpis . ENM of vectors and human cases provided a greater understanding of the geographic distribution of VL in MS, which can be applied to the development of future surveillance strategies.  相似文献   

9.

Introduction

As Plasmodium falciparum prevalence decreases in many parts of Sub-Saharan Africa, so does immunity resulting in larger at risk populations and increased risk of malaria resurgence. In Bissau, malaria prevalence decreased from ∼50% to 3% between 1995 and 2003. The epidemiological characteristics of P. falciparum malaria within Bandim health and demographic surveillance site (population ∼100000) between 1995 and 2012 are described.

Methods and Findings

The population was determined by census. 3603 children aged <15 years that were enrolled in clinical trials at the Bandim health centre (1995–2012) were considered incident cases. The mean annual malaria incidence per thousand children in 1995–1997, 1999–2003, 2007, 2011, 2012 were as follows; age <5 years 22→29→4→9→3, age 5–9 years 15→28→4→33→12, age 10–14 years 9→15→1→45→19. There were 4 campaigns (2003–2010) to increase use of insecticide treated bed nets (ITN) amongst children <5 years. An efficacious high-dose chloroquine treatment regime was routinely used until artemisinin based combination therapy (ACT) was introduced in 2008. Long lasting insecticide treated bed nets (LLIN) were distributed in 2011. By 2012 there was 1 net per 2 people and 97% usage. All-cause mortality decreased from post-war peaks in 1999 until 2012 in all age groups and was not negatively affected by malaria resurgence.

Conclusion

The cause of decreasing malaria incidence (1995–2007) was probably multifactorial and coincident with the use of an efficacious high-dose chloroquine treatment regime. Decreasing malaria prevalence created a susceptible group of older children in which malaria resurged, highlighting the need to include all age groups in malaria interventions. ACT did not hinder malaria resurgence. Mass distribution of LLINs probably curtailed malaria epidemics. All-cause mortality was not negatively affected by malaria resurgence.  相似文献   

10.
Acoustic-based monitoring has proved useful for many birds and seems promising for the endangered red-crowned crane. However, its validity in crane conservation is unclear in the absence of knowledge concerning the long-term stability of pair-specific duets. The red-crowned crane is monogamous and long-lived, with stable pair bonding both within and between years. Pair mates perform loud duets—a succession of male and female calls emitted with definite temporal coordination. We examined the stability of duets for five captive pairs over five years (2003–2007) on the basis of analysis of the syllables within the duets. MANOVA showed that the effect of pair identity on syllable characteristics was always stronger than the effect of the year of recording. Cross-validation of duets from 2004, 2005, 2006, and 2007 with discriminant analysis (DFA) functions derived, respectively, from pooled samples from 2003, 2003–2004, 2003–2005, and 2003–2006 resulted in comparably high percentages of correct classification into pairs. The pairs could be reliably identified by their duets and pair-specific differences in syllable characteristics were stable with time. These data suggest acoustic monitoring is a feasible alternative to more invasive methods of identification.  相似文献   

11.
We investigated sex‐related site fidelity by humpback whales to the Fueguian Archipelago, a new feeding area in the eastern South Pacific, by examining the resighting histories of 45 males and 39 females recorded from 2003 to 2012. Results indicated an overall annual return to the feeding area of 74.8%, and annual sex ratio is roughly equal in the population. The probability of an individual being resighted across years and in subsequent years was not significantly different for both males and females, however, the proportion of resighting within a year was significantly higher for individual males compared to females. Potential sources of sex‐related bias were analyzed, but none were found to be significant. Greater intraannual resighting frequency for males may reflect sex‐based differences in spatial occupation and short‐range movements due to potential differences in energy budgets.  相似文献   

12.
The Arctic Ocean is undergoing rapid transformation toward a seasonally ice‐free ecosystem. As ice‐adapted apex predators, polar bears (Ursus maritimus) are challenged to cope with ongoing habitat degradation and changes in their prey base driven by food‐web response to climate warming. Knowledge of polar bear response to environmental change is necessary to understand ecosystem dynamics and inform conservation decisions. In the southern Beaufort Sea (SBS) of Alaska and western Canada, sea ice extent has declined since satellite observations began in 1979 and available evidence suggests that the carrying capacity of the SBS for polar bears has trended lower for nearly two decades. In this study, we investigated the population dynamics of polar bears in Alaska''s SBS from 2001 to 2016 using a multistate Cormack–Jolly–Seber mark–recapture model. States were defined as geographic regions, and we used location data from mark–recapture observations and satellite‐telemetered bears to model transitions between states and thereby explain heterogeneity in recapture probabilities. Our results corroborate prior findings that the SBS subpopulation experienced low survival from 2003 to 2006. Survival improved modestly from 2006 to 2008 and afterward rebounded to comparatively high levels for the remainder of the study, except in 2012. Abundance moved in concert with survival throughout the study period, declining substantially from 2003 and 2006 and afterward fluctuating with lower variation around an average of 565 bears (95% Bayesian credible interval [340, 920]) through 2015. Even though abundance was comparatively stable and without sustained trend from 2006 to 2015, polar bears in the Alaska SBS were less abundant over that period than at any time since passage of the U.S. Marine Mammal Protection Act. The potential for recovery is likely limited by the degree of habitat degradation the subpopulation has experienced, and future reductions in carrying capacity are expected given current projections for continued climate warming.  相似文献   

13.
(R)‐(+) and (S)‐(?)‐1‐phenylethylamine have been shown to promote highly diastereoselective and complementary enantioselective formal [3 + 2]carbocyclization reactions between 2,3‐butanedione and conjugated nitroalkenes with formation of enantiomerically rich 2‐hydroxy‐3‐nitrocyclopentanone derivatives. The reactions were carried out both in solvent and under solvent‐free conditions. The absolute configurations of the products were assigned by X‐ray and circular dichroism spectra analyses. Chirality 24:1005–1012, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

14.
北部湾是中华白海豚和江豚的重要分布区,但是对该水域两物种的分布格局及时空变化的研究却比较少,也不清楚这两个物种分布区是否有重叠。2003 ~ 2004 年与2011 ~2012 年期间,我们在北部湾沙田水域进行了船只调查,总计航程4 876.8 km,收集了两个物种空间分布的数据。结果表明,2003 ~ 2004 年仅发现中华白海豚,2011 ~2012 年则同时发现了中华白海豚和江豚。与2003 ~ 2004 年4 ~ 5 月相比,中华白海豚在2011 年4 ~ 5 月份的遇见率明显增加(0.152 vs 0. 028 头次/km)。中华白海豚的MCP、95% FK 家域和50% FK 核心域面积分别为162. 6 km2 、271. 35 km2 和56.78 km2 ,2011 ~ 2012 年50% FK 核心家域有所扩大且东移。江豚的MCP、95% FK家域和50% FK 核心域面积分别为97.21 km2 、318.72 km2 和38.18 km2 。江豚主要分布于中华白海豚的外围远岸水域,同时两个物种的分布区有小部分重叠。基于多种因素的分析,我们推测,江豚可能存在季节性迁移以及中华白海豚对河口区有明显的偏好,可能是造成它们分布格局不同的原因。  相似文献   

15.
Capsule The UK Corncrake population increase has slowed, but has rapidly recovered from a large decline in 2013.

Aims To provide an update on the population size and distribution of breeding Corncrakes in the UK, including the results of the most recent full national survey and annual monitoring of the core population.

Methods A full survey of singing Corncrakes was undertaken in the UK and the Isle of Man in 2009, following the last full censuses in 1978/79, 1988, 1993, 1998 and 2003. Monitoring of singing male Corncrakes within the core range in northern and western Scotland has been undertaken annually since 1993.

Results The 2009 results show that numbers increased substantially since 2003, from 829 to 1166 singing males. Corncrake numbers in the core range have increased in 17 of the 21 years between 1993 and 2014, and peaked at 1274 singing males, in 2014. Numbers of singing males dropped by 24% between 2012 and 2013, probably due to a particularly cold spring in 2013 that inhibited growth of vegetation cover, but numbers recovered markedly in 2014.

Conclusion The recovery of the UK Corncrake population has continued since a low point in 1993. However there are no signs of range expansion into mainland UK, away from the core breeding areas in Scotland. The large decline in the core population between 2012 and 2013 highlights the sensitivity of the population to external factors, although the subsequent increase in 2014 shows a capacity for rapid recovery.  相似文献   

16.
The aim of the present work conducted at the Refugio de Vida Silvestre Bahía Samborombón, Argentina, is to analyse the most relevant aspects of the life cycles of Chasmagnathus granulatus and Uca uruguayensis: their abundance, size distribution and sex ratio in order to be used for make management purposes. A total of 1200 individuals of U. uruguayensis (megalopae, juveniles and adults) and 957 individuals of C. granulatus (juveniles and adults) were collected from March 2001 to February 2003. U.␣uruguayensis had a maximun density of 42 ind./m2 in February 2003, while the maximun density of C.␣granulatus was 52 ind./m2 in June 2001. Minimun density was zero individual for both species in July 2002. Each environmental factor sampled (temperature of water, salinity and pH) was correlated with the abundance of each species by Pearson’s linear correlation analysis. Sex ratio did not significantly differ from the expected Mendelian ratio, except for U. uruguayensis in December 2002 (male-biassed) and C.␣granulatus in June and December 2001, April 2002 and February 2003 (female-biassed). Ovigerous females of U. uruguayensis and C. granulatus were found during the summer.  相似文献   

17.
Meta-analyses are increasingly popular. It is unknown whether this popularity is driven by specific countries and specific meta-analyses types. PubMed was used to identify meta-analyses since 1995 (last update 9/1/2012) and catalogue their types and country of origin. We focused more on meta-analyses from China (the current top producer of meta-analyses) versus the USA (top producer until recently). The annual number of meta-analyses from China increased 40-fold between 2003 and 2011 versus 2.4-fold for the USA. The growth of Chinese meta-analyses was driven by genetics (110-fold increase in 2011 versus 2003). The HuGE Navigator identified 612 meta-analyses of genetic association studies published in 2012 from China versus only 109 from the USA. We compared in-depth 50 genetic association meta-analyses from China versus 50 from USA in 2012. Meta-analyses from China almost always used only literature-based data (92%), and focused on one or two genes (94%) and variants (78%) identified with candidate gene approaches (88%), while many USA meta-analyses used genome-wide approaches and raw data. Both groups usually concluded favorably for the presence of genetic associations (80% versus 74%), but nominal significance (P<0.05) typically sufficed in the China group. Meta-analyses from China typically neglected genome-wide data, and often included candidate gene studies published in Chinese-language journals. Overall, there is an impressive rise of meta-analyses from China, particularly on genetic associations. Since most claimed candidate gene associations are likely false-positives, there is an urgent global need to incorporate genome-wide data and state-of-the art statistical inferences to avoid a flood of false-positive genetic meta-analyses.  相似文献   

18.
19.

Objective

In 2011, the National Health Interview Survey (NHIS), an in-person household interview, revised the human immunodeficiency virus (HIV) section of the survey and the Behavioral Risk Factor Surveillance System (BRFSS), a telephone-based survey, added cellphone numbers to its sampling frame. We sought to determine how these changes might affect assessment of HIV testing trends.

Methods

We used linear regression with pairwise contrasts with 2003-2013 data from NHIS and BRFSS to compare percentages of persons aged 18-64 years who reported HIV testing in landline versus cellphone-only households before and after 2011, when NHIS revised its in-person questionnaire and BRFSS added cellphone numbers to its telephone-based sample.

Results

In NHIS, the percentage of persons in cellphone-only households increased 13-fold from 2003 to 2013. The percentage ever tested for HIV was 6%–10% higher among persons in cellphone-only than landline households. The percentage ever tested for HIV increased significantly from 40.2% in 2003 to 45.0% in 2010, but was significantly lower in 2011 (40.6%) and 2012 (39.7%). In BRFSS, the percentage ever tested decreased significantly from 45.9% in 2003 to 40.2% in 2010, but increased to 42.9% in 2011 and 43.5% in 2013.

Conclusions

HIV testing estimates were lower after NHIS questionnaire changes but higher after BRFSS methodology changes. Data before and after 2011 are not comparable, complicating assessment of trends.  相似文献   

20.
目的了解荔湾区2008—2012年水痘疫情的流行情况,为制定水痘疫情防制措施提供科学依据。方法对2008—2012年荔湾区报告的水痘病例及水痘暴发数据,采用Excel2003软件整理后,进行描述性流行病学分析,并结合当前有关文献资料提出今后水痘防制的建议。结果 2008—2012年广州市荔湾区共报告水痘5 814例,年均发病率为129.46/10万。年发病率为83.50/10万~165.33/10万,其间2008年最高,2012年最低;全区22条街都有病例发生;全年12个月均有病例发生,呈冬春季高发态势;发病主要集中在儿童和青少年,学生占42.89%;男女比例为1.4∶1,报告病例中20岁以下者4 690例,占总数80.67%(4 690/5 814);集体单位聚集性疫情13起,其中暴发疫情4起。结论荔湾区近年水痘疫情主要发生在冬春季节,学生和托幼儿童及散居儿童是水痘的高发人群。建议加强普及防控水痘基本知识,提高水痘疫苗第1剂接种率,落实应急接种的同时,开展水痘疫苗第2剂接种程序的研讨,确保水痘疫情的有效控制,保护公众健康。  相似文献   

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