Geographic spatial autocorrelation and United States suicide patterns

Research on aggregated geographical data in such fields as genetics and epidemiology have produced inefficient findings when spatial autocorrelation is present. This inefficiency results from the bias in the standard errors of the regression coefficients for multi-variate studies. It is unclear as to whether the numerous suicide studies that utilize geographical units of analysis am also flawed. The present study employs Odland's test for spatial autocorrelation to ascertain whether this error is present in geographical suicide studies. Two typical studies that employ state and county (parish) data art examined to decide whether spatial autocorrelation limits the findings of these studies. Using a conservative randomization test with Moran's I, it is concluded that for these studies spatial autocorrelation is not a serious problem. However, other weight matrices, and less conservative tests are needed to further support the findings of this paper.     

An accumulator model for spontaneous neural activity prior to self-initiated movement

A gradual buildup of neuronal activity known as the “readiness potential” reliably precedes voluntary self-initiated movements, in the average time locked to movement onset. This buildup is presumed to reflect the final stages of planning and preparation for movement. Here we present a different interpretation of the premovement buildup. We used a leaky stochastic accumulator to model the neural decision of “when” to move in a task where there is no specific temporal cue, but only a general imperative to produce a movement after an unspecified delay on the order of several seconds. According to our model, when the imperative to produce a movement is weak, the precise moment at which the decision threshold is crossed leading to movement is largely determined by spontaneous subthreshold fluctuations in neuronal activity. Time locking to movement onset ensures that these fluctuations appear in the average as a gradual exponential-looking increase in neuronal activity. Our model accounts for the behavioral and electroencephalography data recorded from human subjects performing the task and also makes a specific prediction that we confirmed in a second electroencephalography experiment: Fast responses to temporally unpredictable interruptions should be preceded by a slow negative-going voltage deflection beginning well before the interruption itself, even when the subject was not preparing to move at that particular moment.     

Slowing down as an early warning signal for abrupt climate change

In the Earth's history, periods of relatively stable climate have often been interrupted by sharp transitions to a contrasting state. One explanation for such events of abrupt change is that they happened when the earth system reached a critical tipping point. However, this remains hard to prove for events in the remote past, and it is even more difficult to predict if and when we might reach a tipping point for abrupt climate change in the future. Here, we analyze eight ancient abrupt climate shifts and show that they were all preceded by a characteristic slowing down of the fluctuations starting well before the actual shift. Such slowing down, measured as increased autocorrelation, can be mathematically shown to be a hallmark of tipping points. Therefore, our results imply independent empirical evidence for the idea that past abrupt shifts were associated with the passing of critical thresholds. Because the mechanism causing slowing down is fundamentally inherent to tipping points, it follows that our way to detect slowing down might be used as a universal early warning signal for upcoming catastrophic change. Because tipping points in ecosystems and other complex systems are notoriously hard to predict in other ways, this is a promising perspective.     

2011—2020年安徽省钉螺分布时空分析

目的　分析2011—2020年安徽省钉螺分布时空特征,为全省钉螺精准防控提供参考。方法　收集2011—2020年安徽省实有钉螺面积、新发钉螺面积和感染性钉螺面积等钉螺分布指标并进行描述性分析,对实有和新发钉螺面积进行空间自相关、热点分析、标准差椭圆分析及时空扫描等分析,探索安徽省钉螺聚集与扩散高风险区。结果　2011—2020年,安徽省实有钉螺面积逐渐降低。2020年全省实有钉螺面积26 238.85 hm2,主要分布在湖沼型血吸虫病流行区。各年份间新发钉螺面积波动较大,2016年最高（1 287.65 hm2）;2020年在池州市贵池区新发现1.96 hm2感染性钉螺面积。空间自相关和热点分析显示,2011—2020年安徽省实有钉螺面积分布具有空间聚集性（Z = 3.00 ~ 3.43,P均 < 0.01）,热点主要集中在湖沼型流行区并沿长江南岸分布;冷点主要集中在皖南山区。2011—2020年安徽省新发钉螺面积分布在整体上不存在空间聚集性（Z = -2.20 ~ 1.71,P均> 0.05）,局部呈散点分布。标准差椭圆分析显示,2011—2020年安徽省实有钉螺面积分布相对稳定,与长江流向一致;新发钉螺面积分布重心逐渐从长江安徽段下游向上游移动。时空扫描分析显示,2011—2020年安徽省实有钉螺面积两个高值聚集区以从长江安徽段下游到中游的顺序出现;新发钉螺面积两个高值聚集区聚集时间和范围类似,均分布在山区。结论　2011—2020年安徽省钉螺分布呈空间聚集性,存在向长江南岸、上游聚集的趋势,但山区钉螺扩散问题亦不容忽视,需加强对山区和长江沿岸新发钉螺孳生地的监测力度。     

山东省发热伴血小板减少综合征时空流行特征分析

目的 分析山东省发热伴血小板减少综合征(SFTS)的时空分布特征,为查找重点区域及聚集时间,采取针对性的干预措施,优化卫生资源配置提供科学依据。方法 基于2010-2016年山东省各县(市、区)网络报告的SFTS疫情数据,结合人口数据、地理数据,建立地理信息数据库,采用Open GeoDa 1.2.0软件进行空间自相关分析,采用SaTScan 9.4软件进行时空扫描聚类分析。结果 2010-2016年山东省累计报告SFTS病例2 319例,平均发病率为0.34/10万,累计报告死亡病例230例,平均病死率9.92%,发病数和发病率逐年增多。全局自相关分析显示,2012-2016年SFTS空间分布均具有自相关性,呈聚集性分布, Moran’s I值均为正值(P<0.05);局部自相关分析结果表明,高-高流行区主要位于淄博、泰安、莱芜、威海、烟台等市的相关县区。时空扫描分析发现3个时空聚集区域:1)2012年1月至2015年1月,以烟台市芝罘区为中心点,共覆盖16个县(市、区)(LLR=677.15,RR=11.58,P<0.001)。2)2013年1月至2016年12月,以泰安市新泰市为中心点,共覆盖6个县(市、区)(LLR=457.51,RR=9.25,P<0.001)。3) 2013年1月至2014年1月,以潍坊市安丘市为中心点,共覆盖28个县(市、区)(LLR=142.59, RR=4.97,P<0.001)。结论 山东省发热伴血小板减少综合征疫情分布存在明显的时空聚集特征,主要集中在泰安、莱芜、烟台、威海的相关县(市、区),是我省预防控制该病的重点区域。     

湖北省2008－2012年血吸虫病空间流行分析

目的 分析湖北省血吸虫病流行区县(市、区)级别血吸虫病的流行状况以及空间分布规律. 方法 回顾性分析2008－2012年湖北省血吸虫病流行县(市、区)人群疫情数据资料,并与湖北省GIS地理空间数据库进行匹配,构建湖北省血吸虫病的空间分析数据库.运用全局空间自相关的Moran''s I指标以及局部空间自相关的Getis-Ord Gi^*指标分析湖北省血吸虫病的空间聚集性.结果 2008－2012年湖北省血吸虫病人数、居民血吸虫感染率均呈下降趋势.5年间居民血吸虫感染率的全局空间自相关分析结果有统计学意义(Moran''s I>0,P<0.01).局部空间自相关分析结果显示,居民血吸虫感染率高值聚集县(市、区)数在8～11个,呈现先增加后减少的趋势.高值聚集区主要分布在荆州区、沙市区、江陵县、公安县、石首市、监利县、洪湖市和赤壁市8个县(市、区).结论 2008－2012年湖北省县(市、区)级居民血吸虫感染率分布存在空间自相关,有空间聚集现象,且高值聚集区主要分布在长江流域江汉平原范围.     

Persistent variations in average height between countries and between socio-economic groups: an overview of 10 European countries

Primary objectives: This paper aims to provide an overview of variations in average height between 10 European countries, and between socio-economic groups within these countries.

Data and methods: Data on self-reported height of men and women aged 20-74 years were obtained from national health, level of living or multipurpose surveys for 1987-1994. Regression analyses were used to estimate height differences between educational groups and to evaluate whether the differences in average height between countries and between educational groups were smaller among younger than among older birth cohorts.

Results: Men and women were on average tallest in Norway, Sweden, Denmark and the Netherlands and shortest in France, Italy and Spain (range for men: 170-179 cm; range for women: 160-167 cm). The differences in average height between northern and southern European countries were not smaller among younger than among older birth cohorts. In most countries average height increased linearly with increasing birth-year (≈0.7-0.8cm/5 years for men and ≈0.4cm/5 years for women). In all countries, lower educated men and women on average were shorter than higher educated men (range of differences: 1.6-3.0 cm) and women (range of differences: 1.2-2.2 cm). In most countries, education-related height differences were not smaller among younger than among older birth cohorts.

Conclusions: The persistence of international differences in average height into the youngest birth cohorts indicates a high degree of continuity of differences between countries in childhood living conditions. Similarly, the persistence of education-related height differences indicates continuity of socio-economic differences in childhood living conditions, and also suggests that socio-economic differences in childhood living conditions will continue to contribute to socio-economic differences in health at adult ages.     

安徽、江西及江苏3省血吸虫病患者与钉螺分布的空间自相关分析

目的　通过地理信息系统 (GIS)分析江苏、安徽、江西 3省血吸虫病疫情空间分布规律。　方法　收集 3省近 2 0年的血吸虫病流行病学数据 ,建立 GIS空间数据库。在 Arc View3.x,S- PL U S及 Spatial Statistics软件 (模块 )支持下对建立的血吸虫病 GIS数据库进行空间自相关性分析。　结果　安徽及江西省血吸虫病患者总数及钉螺总面积不同代表年份中 ,均具有不同程度的空间自相关性。总体上钉螺分布的相关系数 (Moran′I )大于患者的相关系数 ,并具有非常显著性差异。江苏省钉螺总面积具有一定的空间自相关性 ,其空间聚集性显著高于血吸虫病患者数 ,两者间缺乏空间聚集性。　结论　空间自相关分析可用于血吸虫病患者、钉螺分布的地域聚集性的研究 ,以揭示该病的分布规律和流行态势     

淄博市2013-2015年手足口病空间自相关分析

目的分析淄博市2013-2015年手足口病的空间分布特征及空间聚集性.方法运用空间自相关分析方法,以乡镇为空间单位对淄博市手足口病监测数据进行分析.结果2013-2015年,全局Moran's I系数分别为0.15(P＜0.001)、0.08(P=0.070)和0.30(P＜0.001).局域G统计量显示,2013年和2014年淄博市手足口病发病热点主要位于高青县,2015年发病热点主要位于周村区及其邻近乡镇.结论淄博市手足口病发病存在明显的空间聚集性,发病热点的探测有助于淄博市手足口病区域化防控策略的制定.