Turning point

  • 文章类型: Journal Article
    尽管研究结果表明,抑郁症患者的个人记忆以稀疏的情节细节为特征,在某些情况下,相反的模式出现了。具体来说,最近的一项研究(Salmon等人。,2021)表明,对于社区青年来说,在高度自我相关的叙述(人生转折点)中更多的情节细节预测抑郁症状同时和一年后增加。在一项针对年轻人的新纵向研究中(时间1时N=320,M=16.9岁;81%为女性),随访6个月以上,我们旨在复制和扩展这一发现。在研究A中,我们将转折点与关于冲突事件的叙述进行了比较,确定转折点记忆中的细节是否唯一地预测了抑郁症状。支持第一个假设,在这两个时间点,更多的情节细节与抑郁症状同时呈正相关,仅在转折点叙述中.与我们的第二个假设相反,更多细节并不能纵向预测抑郁症状增加.反向模式很明显,然而,在六个月后的转折点叙述中,更大的初始抑郁症状预测了更多的细节。在研究B中,我们确定,在转折点(而非冲突事件)中,情景细节和抑郁症状之间的并发关联因自我聚焦的语言标记(I-talk更大,距离更低)而加剧.这些发现表明,当年轻人以高度的自我专注来叙述经历时,转折点叙事中的更多细节可能独特地表示心理困扰的风险。
    Although research findings show that the personal memories of people who are depressed are characterized by sparse episodic detail, under some circumstances, the opposite pattern emerges. Specifically, a recent study (Salmon et al., 2021) has shown that for community youth, greater episodic detail in a highly self-relevant narrative (a life turning point) predicted increased depressive symptoms concurrently and one year later. In a new longitudinal study of young people (N = 320 at Time 1, M = 16.9 years; 81% female) followed up over six months, we aimed to replicate and extend this finding. In Study A, we compared the turning point with a narrative about a conflict event, to establish whether the detail in a turning point memory uniquely predicted depressive symptoms. Supporting the first hypothesis, at both time-points, greater episodic detail was concurrently positively associated with depressive symptoms for turning point narratives only. Contrary to our second hypothesis, greater detail did not predict increased depressive symptoms longitudinally. The reverse pattern was significant, however, in that greater initial depressive symptoms predicted greater detail uniquely in the turning point narrative six months later. In Study B, we determined that the concurrent association between episodic detail and depressive symptoms in turning points (but not conflict events) was exacerbated by linguistic markers of self-focus (greater I-talk and lower distancing language). These findings suggest that greater detail in a turning point narrative may uniquely signify risk of psychological distress when youth narrate the experience with heightened self-focus.
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  • 文章类型: Journal Article
    本文的目的是基于2019年11月20日至2020年6月3日的日内数据,研究20种商品期货的过度反应行为,重点是新冠肺炎大流行的影响。对四个不同频率(从1分钟到1小时)和两个不同子时段(新冠肺炎大流行前和新冠肺炎大流行期间)的日内数据应用了动态和非参数方法,以检测过度反应行为,这被定义为价格的大幅变化,然后是成比例的价格反转。我们的实证结果表明,对于所考虑的商品期货,反应过度假设得到了证实。此外,在新冠肺炎大流行期间,过度反应的数量和幅度都较高。我们的发现还表明,与贵金属,尤其是能源商品相比,软商品和金属商品的过度反应要少得多。特别是,与其他商品相比,原油期货表现出不同的过度反应行为,因为在新冠肺炎大流行期间,原油期货的负面反应数量高于正面反应数量。我们还发现,数据频率与两个时期的过度反应行为无关,因为当由于更高的频率而进行更多的观察时,结果会不断改善。最后,我们发现,新冠肺炎大流行期间的极端过度反应为有利可图的交易回报提供了巨大的潜力,可以被交易者利用。
    The objective of this paper is to examine the overreaction behavior of 20 commodity futures based on intraday data from November 20, 2019 to June 3, 2020 with a focus on the impact of the Covid-19 pandemic. A dynamic and non-parametric approach is applied on intraday data for four different frequencies (from 1 min to 1 h) and two different sub-periods (pre-Covid-19 pandemic and during Covid-19 pandemic) in order to detect overreaction behavior which is defined as a large change of prices followed by proportional price reversals. Our empirical findings show that the overreaction hypothesis is confirmed for the considered commodity futures. Furthermore, both the number and the amplitude of overreactions is higher during the Covid-19 pandemic. Our findings also indicate that soft and metal commodities show much less overreactions than precious metals and especially energy commodities. In particular, crude oil futures exhibit a different overreaction behavior compared to other commodities since it has a higher number of negative than positive overreactions during the Covid-19 pandemic. We also find that the data frequency is independent of the overreacting behavior in both periods as the results continuously improve when having more observations due to higher frequencies. Finally, we find that extreme overreactions during the Covid-19 pandemic provide a great potential for profitable trading returns, which can be exploited by traders.
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  • 文章类型: Journal Article
    危险功能在癌症患者生存研究中起着重要作用,因为它量化了患者在任何给定时间的瞬时死亡风险。通常在癌症临床试验中,观察到单峰危险函数,感兴趣的是检测(估计)危险函数的转折点(模式),因为这可能是癌症患者治疗策略的重要措施。此外,当病人治愈是可能的时候,估计癌症不同阶段的治愈率,除了他们的比例,可以更好地总结分期对生存率的影响。因此,本文的主要目的是考虑在存在长期存活者的情况下,评估不同阶段宫颈癌患者的危险功能模式的问题。为此,提出了一种基于对数Logistic分布的混合治愈率模型。该模型通过危险函数的模式方便地参数化,其中癌症分期可以影响治愈分数和模式。此外,我们通过最大似然估计方法讨论模型推断的方面。蒙特卡罗模拟研究评估了渐近置信区间的覆盖概率。
    The hazard function plays an important role in cancer patient survival studies, as it quantifies the instantaneous risk of death of a patient at any given time. Often in cancer clinical trials, unimodal hazard functions are observed, and it is of interest to detect (estimate) the turning point (mode) of hazard function, as this may be an important measure in patient treatment strategies with cancer. Moreover, when patient cure is a possibility, estimating cure rates at different stages of cancer, in addition to their proportions, may provide a better summary of the effects of stages on survival rates. Therefore, the main objective of this paper is to consider the problem of estimating the mode of hazard function of patients at different stages of cervical cancer in the presence of long-term survivors. To this end, a mixture cure rate model is proposed using the log-logistic distribution. The model is conveniently parameterized through the mode of the hazard function, in which cancer stages can affect both the cured fraction and the mode. In addition, we discuss aspects of model inference through the maximum likelihood estimation method. A Monte Carlo simulation study assesses the coverage probability of asymptotic confidence intervals.
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  • 文章类型: Journal Article
    In rapidly developing countries, it is imperative to study the changes in municipal solid waste (MSW) generation for planning waste management and treatment. This study took the largest 11 economies in the world as cases, comprising half of the global population, analyzed the variations of definition of MSW among these economies. Based on the Environmental Kuznets Curve (EKC) hypothesis and using parametric model, Feasible General Least Squares (FGLS) regression, and nonparametric models, Generalized Additive Mixed Models (GAMMs), it was expected that the change features and its socioeconomic drivers of total MSW generation and per capita MSW (PCMSW) since the 1960s would be determined. Efforts were also made to find the turning/stabilizing point in the relationship between PCMSW and per capita gross domestic product (PCGDP) in each economy. It shows that population has the most important impact on total MSW, however, the economic indicators might be ignored. The United States and Germany have the highest PCMSW generation, while China and India indicate the lowest. The turning/stabilizing point in the relationship between PCMSW and PCGDP perfermed in most developed economies, Singapore and Korea reached the turning point around 1990, while for other developed economies it was 2000. Germany came to a stabilizing point in 1990, and with some arbitrary, so did the United States. The developing economies seem to be still in their early stage of the potential EKC. In developed economies, heterogeneous time effects on PCMSW seem to be more significant than heterogeneous income effects, which is contrary to developing economies.
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  • 文章类型: Journal Article
    在本文中,我们根据当前确诊病例的数量进行长期预测,通过建模方法研究中国不同地区COVID-19的累计死亡病例。首先,我们使用SIRD流行病模型(S-Susceptible,我感染了,R-恢复,D-Dead)是一个具有孵化时间延迟的非自治动态系统,用于研究武汉市COVID-19的演变,湖北省和中国大陆。根据前期中国国家卫生健康委员会发布的数据,我们可以准确地估计模型的参数,然后准确预测那里的COVID-19的演变。从发布的数据分析来看,我们发现武汉市的治愈率,湖北省和中国大陆是时间t的近似线性递增函数,其死亡率是分段递减函数。这些可以通过有限差分法估计。其次,我们使用延迟SIRD流行模型来研究COVID-19在武汉市以外的湖北省的演变。我们发现其治愈率是近似线性增加的函数,其死亡率几乎是一个常数。第三,我们使用延迟SIR流行模型(S-Susceptible,我感染了,R-删除)来预测北京的情况,上海,浙江省和安徽省。我们发现它们的治愈率是近似线性增加的函数,它们的死亡率是小常数。结果表明,可以对当前确认的数量进行准确的长期预测,通过建模,COVID-19的累计死亡病例。本文的结果表明,我们可以准确地获得和预测转折点,中国目前感染和死亡病例的结束时间和最大数量。尽管我们的方法简单,数据小,它在COVID-19的长期预测中相当有效。
    In this paper, we make long-term predictions based on numbers of current confirmed cases, accumulative dead cases of COVID-19 in different regions in China by modeling approach. Firstly, we use the SIRD epidemic model (S-Susceptible, I-Infected, R-Recovered, D-Dead) which is a non-autonomous dynamic system with incubation time delay to study the evolution of the COVID-19 in Wuhan City, Hubei Province and China Mainland. According to the data in the early stage issued by the National Health Commission of China, we can accurately estimate the parameters of the model, and then accurately predict the evolution of the COVID-19 there. From the analysis of the issued data, we find that the cure rates in Wuhan City, Hubei Province and China Mainland are the approximately linear increasing functions of time t and their death rates are the piecewisely decreasing functions. These can be estimated by finite difference method. Secondly, we use the delayed SIRD epidemic model to study the evolution of the COVID-19 in the Hubei Province outside Wuhan City. We find that its cure rate is an approximately linear increasing function and its death rate is nearly a constant. Thirdly, we use the delayed SIR epidemic model (S-Susceptible, I-Infected, R-Removed) to predict those of Beijing, Shanghai, Zhejiang and Anhui Provinces. We find that their cure rates are the approximately linear increasing functions and their death rates are the small constants. The results indicate that it is possible to make accurate long-term predictions for numbers of current confirmed, accumulative dead cases of COVID-19 by modeling. In this paper the results indicate we can accurately obtain and predict the turning points, the end time and the maximum numbers of the current infected and dead cases of the COVID-19 in China. In spite of our simple method and small data, it is rather effective in the long-term prediction of the COVID-19.
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  • 文章类型: Journal Article
    虽然疫苗接种在全球范围内进行,疫苗接种率差异很大。截至2021年5月24日,在一些国家,完全接种COVID-19疫苗的人口比例已超过50%,但在许多国家,这个比例仍然很低,不到1%。本文旨在探讨疫苗接种对COVID-19大流行传播的影响。由于世界上几乎所有国家的羊群豁免权都没有达到,通过采用以下标准选择了几个国家作为样本病例:每100人超过60剂疫苗和超过100万人的人口。最后,总共选择了八个国家/地区,包括以色列,阿联酋,智利,联合王国,美国,匈牙利,卡塔尔。结果发现,疫苗接种对降低所有国家的感染率都有重大影响。然而,接种疫苗后的感染率呈现两种趋势。一个是倒U型趋势,另一种是L型趋势。对于那些呈倒U型趋势的国家,当疫苗接种率达到每100人1.46-50.91剂量时,感染率开始下降。
    Although vaccination is carried out worldwide, the vaccination rate varies greatly. As of 24 May 2021, in some countries, the proportion of the population fully vaccinated against COVID-19 has exceeded 50%, but in many countries, this proportion is still very low, less than 1%. This article aims to explore the impact of vaccination on the spread of the COVID-19 pandemic. As the herd immunity of almost all countries in the world has not been reached, several countries were selected as sample cases by employing the following criteria: more than 60 vaccine doses per 100 people and a population of more than one million people. In the end, a total of eight countries/regions were selected, including Israel, the UAE, Chile, the United Kingdom, the United States, Hungary, and Qatar. The results find that vaccination has a major impact on reducing infection rates in all countries. However, the infection rate after vaccination showed two trends. One is an inverted U-shaped trend, and the other is an L-shaped trend. For those countries with an inverted U-shaped trend, the infection rate begins to decline when the vaccination rate reaches 1.46-50.91 doses per 100 people.
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  • 文章类型: Journal Article
    最初在湖北发现,武汉,并被世界卫生组织鉴定为冠状病毒家族的新型病毒,COVID-19以指数级的速度在世界范围内传播,造成数百万人死亡和公众恐惧。目前,美国,印度,巴西,世界其他地区正在经历COVID-19的二次浪潮。然而,医学,数学,以及其传播的药物方面,孵化,和恢复过程仍不清楚。经典的易感感染-恢复模型在描述COVID-19的动态行为方面存在局限性。因此,有必要引入递归,潜在模型预测美国未来COVID-19感染病例数。在这篇文章中,提出了一种基于经典SEIR模型的动态递归和潜伏感染模型(RLIM)来预测COVID-19感染的数量。给定一段时间的COVID-19感染和恢复数据,RLIM能够拟合当前值,并根据实际报告的数字以最小的错误率生成一组最佳参数。分配了这些最佳参数,然后,RLIM模型能够在一定时期内产生感染数量的预测。为了定位COVID-19传输的转折点,二次感染率的初始值给出给RLIM算法进行计算。然后,RLIM将使用迭代搜索策略计算连续时间序列的继发感染率,以加快预测结果的收敛速度并最小化最大平方误差。与其他预测算法相比,RLIM能够更快、更准确地适应COVID-19感染曲线,更重要的是,提供了一种方法,通过寻找恢复和新感染之间的平衡来确定病毒传播的转折点。对美国四个州的模拟表明,在选定的14天潜伏期内,继发感染率ω最初设定为0.5,RLIM能够在0.07处最小化该值并达到平衡条件。使用纽约州的COVID-19传输生成成功的预测,其中一个转折点预计将在2021年1月31日出现。
    在线版本包含补充材料,可在10.1007/s11071-021-06520-1获得。
    Initially found in Hubei, Wuhan, and identified as a novel virus of the coronavirus family by the WHO, COVID-19 has spread worldwide at exponential speed, causing millions of deaths and public fear. Currently, the USA, India, Brazil, and other parts of the world are experiencing a secondary wave of COVID-19. However, the medical, mathematical, and pharmaceutical aspects of its transmission, incubation, and recovery processes are still unclear. The classical susceptible-infected-recovered model has limitations in describing the dynamic behavior of COVID-19. Hence, it is necessary to introduce a recursive, latent model to predict the number of future COVID-19 infection cases in the USA. In this article, a dynamic recursive and latent infection model (RLIM) based on the classical SEIR model is proposed to predict the number of COVID-19 infections. Given COVID-19 infection and recovery data for a certain period, the RLIM is able to fit current values and produce an optimal set of parameters with a minimum error rate according to actual reported numbers. With these optimal parameters assigned, the RLIM model then becomes able to produce predictions of infection numbers within a certain period. To locate the turning point of COVID-19 transmission, an initial value for the secondary infection rate is given to the RLIM algorithm for calculation. RLIM will then calculate the secondary infection rates of a continuous time series with an iterative search strategy to speed up the convergence of the prediction outcomes and minimize the maximum square errors. Compared with other forecast algorithms, RLIM is able to adapt the COVID-19 infection curve faster and more accurately and, more importantly, provides a way to identify the turning point in virus transmission by searching for the equilibrium between recoveries and new infections. Simulations of four US states show that with the secondary infection rate ω initially set to 0.5 within the selected latent period of 14 days, RLIM is able to minimize this value at 0.07 and reach an equilibrium condition. A successful forecast is generated using New York state\'s COVID-19 transmission, in which a turning point is predicted to emerge on January 31, 2021.
    UNASSIGNED: The online version contains supplementary material available at 10.1007/s11071-021-06520-1.
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  • 文章类型: Journal Article
    Objective: Acupuncture is one of the most widely used treatments of complementary and alternative medicine (CAM) within the military\'s health system. The success of CAM integration is partially dependent on both providers\' and patients\' perceptions that acupuncture is health-promoting. The aim of this research was to identify turning points, or changes, across treatments that enhanced or inhibited physicians\' and patients\' perception of acupuncture as health-promoting. Materials and Methods: Using a retrospective-interview approach, interviews were conducted with 15 family medicine physicians practicing medical acupuncture in a family medicine setting and with 17 patients (N = 32). Turning points were separated into 2 groups (health-promoting or health-inhibiting). Similarities and differences between perspectives were noted. Results: Patients and physicians identified two changes that enhanced their perspective of acupuncture as health-promoting: (1) observed health changes and (2) pain-medicine/narcotic reduction/elimination. Patients identified their ability to fulfill personal or professional roles, whereas physicians identified (1) training experiences and (2) enhanced relationships with patients. Health-inhibiting changes in perspective were identified as logistical constraints/barriers by both parties, although their perspectives differed to some degree. Turning points that were viewed as health-inhibiting treatment were identified as clinical challenges by physicians and as a lack of consistency in care by patients. Conclusions: The insight from these findings can help identify areas where medical acupuncture can be improved to promote successful integration in conventional medicine settings, as well as how providers can tailor communication with patients about acupuncture.
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  • 文章类型: Journal Article
    Existing socio-technical systems tend to be intransigent to change. Decarbonisation, on the other hand, is an imperative, leading to an obvious conflict between the need for, and highly effective resistance to, change. Moreover, the abandonment of fossil fuel-based technologies in favour of more sustainable alternatives will require substantial reallocation of government\'s operational expenditure, particularly in countries like South Africa with high per capita greenhouse gas emissions and low per capita income. In this article, it is argued that reallocation will require more than niche experimentation and destabilisation of the present socio-technical regime. Based on a study of South Africa\'s budget processes, it is concluded that change will only occur when four separate pre-conditions converge, namely a rapidly growing environmental problem capable of leading to civil unrest, a supportive and recently developed policy framework, decreasing techno-economic costs for its solution, and strong political support from an effective ministry or minister. Turning points for transition, although infrequent, can be reached through strategic attention to these pre-conditions. A modified Kingdon multiple streams approach, which introduces the additional dimension of techno-economic feasibility, is proposed as a useful framework for anticipating when and how to act in order to mobilise sufficient public resources for decarbonisation.
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  • 文章类型: Journal Article
    In this paper, we employed a segmented Poisson model to analyze the available daily new cases data of the COVID-19 outbreaks in the six Western countries of the Group of Seven, namely, Canada, France, Germany, Italy, UK and USA. We incorporated the governments\' interventions (stay-at-home advises/orders, lockdowns, quarantines and social distancing) against COVID-19 into consideration. Our analysis allowed us to make a statistical prediction on the turning point (the time that the daily new cases peak), the duration (the period that the outbreak lasts) and the attack rate (the percentage of the total population that will be infected over the course of the outbreak) for these countries.
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