Permanence

持久性
  • 文章类型: Journal Article
    在他们的自然环境中,动物面临各种生态和社会挑战,这可能与不同认知技能的出现有关。为了评估认知技能的特定差异,我们用有蹄类动物作为研究模型,测试了5个不同物种的26个圈养个体(即,矮山羊,Capraaegagrushircus,美洲驼,格拉玛,guanacos,关尼科喇嘛,斑马,Equusgrevyi,还有犀牛,Dicerosbicornismichaeli)。跨物种,我们使用同样完善的实验程序来测试个人在幼稚物理任务中的表现,即对象持久性,短期空间记忆,因果关系,理解对象属性,和重力。我们的结果表明,研究对象表现出客体持久性,能够在60年代后记住隐藏食物的位置,并从摇动容器时产生或不产生的声音推断隐藏食物的位置。此外,他们展示了对基本对象属性的理解,能够根据遮挡物的大小和倾斜度定位隐藏在遮挡物后面的对象,并且可以可靠地跟踪不同条件下坠落物体的轨迹。最后,特定间的差异仅限于对对象属性的理解,并建议驯化物种作为山羊在需要这些技能的任务中可能比非驯化物种表现更好。这些结果为仍未研究的分类单元的认知技能提供了新信息,并确认有蹄类动物是认知进化比较研究的有前途的分类单元。
    In their natural environment, animals face a variety of ecological and social challenges, which might be linked to the emergence of different cognitive skills. To assess inter-specific variation in cognitive skills, we used ungulates as a study model, testing a total of 26 captive individuals across 5 different species (i.e., dwarf goats, Capra aegagrus hircus, llamas, Lama glama, guanacos, Lama guanicoe, zebras, Equus grevyi, and rhinos, Diceros bicornis michaeli). Across species, we used the same well-established experimental procedures to test individuals\' performance in naïve physics tasks, i.e. object permanence, short-term spatial memory, causality, understanding of object properties, and gravity. Our results revealed that study subjects showed object permanence, were able to remember the position of hidden food after up to 60 s, and inferred the position of hidden food from the sound produced or not produced when shaking containers. Moreover, they showed an understanding of basic object properties, being able to locate objects hidden behind occluders based on their size and inclination, and could reliably follow the trajectory of falling objects across different conditions. Finally, inter-specific differences were limited to the understanding of object properties, and suggest that domesticated species as goats might perform better than non-domesticated ones in tasks requiring these skills. These results provide new information on the cognitive skills of a still understudied taxon and confirm ungulates as a promising taxon for the comparative study of cognitive evolution.
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  • 文章类型: Journal Article
    背景:考虑到产妇死亡率高,巴基斯坦政府已在巴基斯坦农村地区部署了社区助产士(CMW)。这个相对较新的以社区为基础的熟练助产士干部以前曾报道过在提供母婴保健方面遇到过一些挑战。然而,他们在提供基本急诊产科和新生儿护理方面遇到的障碍需要进一步研究。
    方法:这是一项在信德省12个地区进行的横断面研究,巴基斯坦,母婴健康指标差。共有258名CMW参加了这项研究,并完成了一份预先测试的问卷,在他们基于社区的站点中使用经过验证的工具。经过培训的数据收集者完成了受访者的问卷。发现的问题分为三个主要问题:财务,与运输和安全相关;并进行了相应的分析。从伊斯兰堡卫生服务学院(HSA)的机构审查委员会(IRB)获得了道德批准,巴基斯坦。
    结果:258名CMW中的大多数(90%)接受了来自公认机构的孕产妇和新生儿护理的正规培训。CMW面临的财务困难被认为是最常见的障碍,其他障碍是运输,安全,和其他问题。在单变量分析中,在经济困难的社区助产士中,有38.1%及61.9%完成毕业或中级教育,分别(p=0.006)。全天候提供紧急情况与财政困难成反比,即,71.4%,相比之下,有经济困难的28.4%的人可以在社区诊所全天候拨打紧急电话(p=0.008)。正式训练(p=0.001),工作经验(p=0.015),较长的工作时间(p=0.003),与卫生工作者和邮政区的联络(p=0.001)在统计学上显著高于与交通相关的问题。CMW面临的安全困难和一系列相关因素,如正式培训(p=0.019),工作经验(p=0.001),较长的工作时间(p=0.023),24小时待命(p=0.004),与社区传统助产士(TBA)的联络(p=0.002),和发布地区(p=0.001)在统计学上有显着差异。其他问题,如工作经验(p=<0.001)和与社区TBA的联系(p=<0.001),具有统计学意义。
    结论:财务,在巴基斯坦农村地区,社区助产士在提供基本紧急产科和新生儿护理时,普遍报告了与交通和安全相关的障碍.
    BACKGROUND: Considering the high maternal mortality rate, the government of Pakistan has deployed Community Midwives (CMWs) in rural areas of Pakistan. This relatively new cadre of community-based skilled birth attendants has previously reported to experience several challenges in providing maternal and child healthcare. However, what barriers they experience in providing basic emergency obstetric and newborn care needs to be further studied.
    METHODS: This was a cross-sectional study conducted in twelve districts in Sindh province, Pakistan, with poor maternal and child health indicators. A total of 258 CMWs participated in this study and completed the questionnaire on a pretested, validated tool in their community-based stations. The trained data collectors completed the questionnaires from the respondents. The problems identified were categorized into three major issues: financial, and transport and security related; and were analyzed accordingly. Ethical approval was obtained from the institutional review board (IRB) of Health Services Academy (HSA) Islamabad, Pakistan.
    RESULTS: The majority (90%) of 258 CMWs had formal training in maternal and neonatal care from the recognized institutions. Financial difficulties faced by CMWs were identified as the most frequent barriers and others were transport, security, and other issues. In univariate analysis, 38.1% and 61.9% of the community midwives who faced financial difficulties had completed a graduation or intermediate level of education, respectively (p = 0.006). Round-the-clock availability for emergencies was inversely associated with having financial difficulties, i.e., 71.4%, in contrast to 28.4% who had financial difficulties were available round-the-clock for emergency calls in their community clinics (p = 0.008). Formal training (p = 0.001), work experience (p = 0.015), longer duration of work (p = 0.003), and liaison with health workers and posting district (p = 0.001) had statistically significantly higher transport related issues. Security difficulties faced by CMWs and a set of correlates such as formal training (p = 0.019), working experience (p = 0.001), longer duration of work (p = 0.023), 24 h of availability on call (p = 0.004), liaison with traditional birth attendants (TBAs) in the community (p = 0.002), and district of posting (p = 0.001) were statistically significantly different. Other issues like working experience (p = < 0.001) and Liaison with TBAs in the community (p = < 0.001) were found statistically significant.
    CONCLUSIONS: Financial, transportation and security related barriers were commonly reported by community midwives in the delivery of basic emergency obstetric and newborn care in rural Pakistan.
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  • 文章类型: Journal Article
    纸张回收是废纸管理的可行选择。这项研究评估了再生纸作为食品包装材料的适用性。三种不同再生纸的持久性和耐久性;R1:150GSM,R2:120GSM,使用标准方法评估具有老化的R3:100GSM。即使不透明度随着克重的老化而增加,爆裂强度,抗拉强度,pH值,亮度,白度下降。回收纸甚至在老化之前也未通过吸水性测试。将再生纸中重金属的存在与食品包装标准进行了比较,并评估了重金属从包装到不同食品类型的迁移。铜的存在,Zn,Mn,Cr,Cd和Pb低于EC和EPA标准,但只有Pb和Cd超过欧盟标准。铜的迁移,Zn,Mn和Cr在EPA范围内,欧盟和欧共体标准,Pb和Cd除外。迁移量最高的食物含有较多的脂肪酸;快餐,香肠和披萨。
    Paper recycling is a viable option for wastepaper management. This study assessed the suitability of recycled papers as a food packaging material. Permanence and durability of three different recycled papers; R1:150 GSM, R2:120 GSM, and R3:100 GSM with aging were evaluated using standard methods. Eventhough opacity increased with aging grammage, burst strength, tensile strength, pH, brightness, and whiteness decreased. Recycled papers failed water absorptiveness test even before aging. Presence of heavy metals in recycled papers were compared with food packaging standards and migration of heavy metals from the packaging to different food types was assessed. Presence of Cu, Zn, Mn, Cr, Cd and Pb were below EC and EPA standards but only Pb and Cd exceeded the EU standard. Migration of Cu, Zn, Mn and Cr were within EPA, EU and EC standards except Pb and Cd with respect to EC standard. Highest migration is associated with foods contain more fatty acids; fast food, sausages and pizza.
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  • 文章类型: Journal Article
    为了了解物种共存的潜在机制,生态学家经常研究理论和数据驱动模型的入侵增长率。相对于支持其他物种的遍历措施,这些增长率对应于一个物种的平均人均增长率。在生态文学中,共存通常等同于入侵增长率为正。直觉上,积极的入侵增长率确保物种从稀有中恢复过来。为了为这种方法提供数学上严格的框架,我们证明了回答两个问题的定理:(i)入侵增长率的迹象何时确定共存?(ii)当迹象足够时,哪些入侵增长率需要为正?我们专注于确定性模型,将共存等同于持久性,即,远离灭绝的全球吸引子。对于满足某些技术假设的模型,我们引入了入侵图,其中顶点对应于支持遍历度量的物种(群落)的适当子集,而有向边缘对应于由于缺少物种的入侵而导致的群落之间的潜在过渡。这些定向边缘由入侵生长速率的迹象决定。当入侵图是非循环的(即没有在同一社区开始和结束的入侵序列)时,我们表明,持久性是由入侵增长率的迹象决定的。在这种情况下,持久性的特征是所有[公式:见文本]社区的可入侵性,即,没有物种i的群落,所有其他缺失的物种都有负的入侵增长率。为了说明结果的适用性,我们证明耗散Lotka-Volterra模型通常满足我们的技术假设,并且计算其入侵图简化为求解线性方程组。我们还将我们的结果应用于具有脉冲资源的竞争物种或共享表现出切换行为的捕食者的模型。讨论了确定性和随机模型的开放问题。我们的结果强调了使用有关社区集会的概念来研究共存的重要性。
    To understand the mechanisms underlying species coexistence, ecologists often study invasion growth rates of theoretical and data-driven models. These growth rates correspond to average per-capita growth rates of one species with respect to an ergodic measure supporting other species. In the ecological literature, coexistence often is equated with the invasion growth rates being positive. Intuitively, positive invasion growth rates ensure that species recover from being rare. To provide a mathematically rigorous framework for this approach, we prove theorems that answer two questions: (i) When do the signs of the invasion growth rates determine coexistence? (ii) When signs are sufficient, which invasion growth rates need to be positive? We focus on deterministic models and equate coexistence with permanence, i.e., a global attractor bounded away from extinction. For models satisfying certain technical assumptions, we introduce invasion graphs where vertices correspond to proper subsets of species (communities) supporting an ergodic measure and directed edges correspond to potential transitions between communities due to invasions by missing species. These directed edges are determined by the signs of invasion growth rates. When the invasion graph is acyclic (i.e. there is no sequence of invasions starting and ending at the same community), we show that permanence is determined by the signs of the invasion growth rates. In this case, permanence is characterized by the invasibility of all [Formula: see text] communities, i.e., communities without species i where all other missing species have negative invasion growth rates. To illustrate the applicability of the results, we show that dissipative Lotka-Volterra models generically satisfy our technical assumptions and computing their invasion graphs reduces to solving systems of linear equations. We also apply our results to models of competing species with pulsed resources or sharing a predator that exhibits switching behavior. Open problems for both deterministic and stochastic models are discussed. Our results highlight the importance of using concepts about community assembly to study coexistence.
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  • 文章类型: Journal Article
    我们在几个时间可变的补丁上考虑年龄结构化的密度相关人口模型。我们基于两个关键假设建立和分析模型。首先,种内竞争仅限于同龄个体之间的竞争(纯队列内竞争),并且影响密度依赖性死亡率.第二,补丁之间的分散确保每个补丁可以从每个其他补丁到达,直接或通过几个中间补丁,在个体生育年龄内。使用强单调性,我们证明了解的存在性和唯一性,并分析了其在常数情况下的大时间行为,周期性变化和不规则变化的环境。类似于下一代运营商,我们为时间无关和周期性模型引入净繁殖算子和基本繁殖数[公式:见文本],并建立持久性二分法:如果[公式:见文本],所有补丁的灭绝迫在眉睫,如果[公式:见文本],保证所有补丁的持久性。我们证明了一般的时间相关问题的解决方案可以通过相关的周期问题的解决方案上下限制。使用双方估计,我们建立了一般时间相关问题的解的一致有界性和一致持久性,并描述了其渐近行为。
    We consider an age-structured density-dependent population model on several temporally variable patches. There are two key assumptions on which we base model setup and analysis. First, intraspecific competition is limited to competition between individuals of the same age (pure intra-cohort competition) and it affects density-dependent mortality. Second, dispersal between patches ensures that each patch can be reached from every other patch, directly or through several intermediary patches, within individual reproductive age. Using strong monotonicity we prove existence and uniqueness of solution and analyze its large-time behavior in cases of constant, periodically variable and irregularly variable environment. In analogy to the next generation operator, we introduce the net reproductive operator and the basic reproduction number [Formula: see text] for time-independent and periodical models and establish the permanence dichotomy: if [Formula: see text], extinction on all patches is imminent, and if [Formula: see text], permanence on all patches is guaranteed. We show that a solution for the general time-dependent problem can be bounded by above and below by solutions to the associated periodic problems. Using two-side estimates, we establish uniform boundedness and uniform persistence of a solution for the general time-dependent problem and describe its asymptotic behaviour.
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  • 文章类型: Journal Article
    功能连接,表示不同大脑区域或电极之间的统计耦合关系,是临床医学和认知神经科学中一个有影响力的概念。脑电图衍生的功能连接(EEG-FC)提供了有关认知任务和个性特征的个体差异的相关特征信息。然而,目前尚不清楚这些个体依赖性EEG-FCs在长期治疗中是否仍然相对持久.该手稿利用机器学习算法来探索静息状态EEG连接模式的个体特异性和持久性。我们在六个月的时间内以不同的间隔进行了六次记录,以检查长期静息状态EEG-FC的变化和持久性。结果表明,EEG-FC网络具有很强的主题特异性,具有大于90%的高精度识别精度。同时,个体特异性保持稳定,6个月后仅略有变化.此外,特异性主要来自额叶的内部连通性。我们的工作证明了大脑中存在特定和永久性的EEG-FC模式,为生物识别应用提供潜在信息。
    Functional connectivity, representing a statistical coupling relationship between different brain regions or electrodes, is an influential concept in clinical medicine and cognitive neuroscience. Electroencephalography-derived functional connectivity (EEG-FC) provides relevant characteristic information about individual differences in cognitive tasks and personality traits. However, it remains unclear whether these individual-dependent EEG-FCs remain relatively permanent across long-term sessions. This manuscript utilizes machine learning algorithms to explore the individual specificity and permanence of resting-state EEG connectivity patterns. We performed six recordings at different intervals during a six-month period to examine the variation and permanence of resting-state EEG-FC over a long period. The results indicated that the EEG-FC networks are quite subject-specific with a high-precision identification accuracy of greater than 90%. Meanwhile, the individual specificity remained stable and only varied slightly after six months. Furthermore, the specificity is mainly derived from the internal connectivity of the frontal lobe. Our work demonstrates the existence of specific and permanent EEG-FC patterns in the brain, providing potential information for biometric applications.
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  • 文章类型: Journal Article
    随着移动网络的普及,社交媒体在工作或我们的个人生活中无处不在。基于媒体同步理论和转换框架,这项研究提出了一个研究模型,并研究了社交媒体的属性如何通过工作导向或社会导向的使用来影响工作效率。采用SmartPLS3.2.8对来自受访者的322份有效问卷数据进行分析。结果表明,通过以工作为导向的社交媒体使用方式,社交媒体的可用性和符号多样性等特征对其工作效率有重大影响。公共性和符号多样性通过社交媒体的社交化使用影响工作效率。此外,以工作为导向的社交媒体和以社交为导向的使用都会影响员工的工作效率。当人们选择社交媒体用于工作或社会目的时,有不同的考虑因素。管理者或公司可以引导他们的员工以正确的方式使用社交媒体,以增加他们的工作功能来完成他们的工作效率,并为员工创建小组,以便有效地共享工作信息。
    As prevail of mobile networking, social media became ubiquitous in either work or our personal life. Based on Media Synchronization Theory and transformational framework, this study proposed a research model and examined how the social media\' attributes impacting the work effectiveness through the work-oriented or social-oriented usage. The data of 322 valid questionnaires from respondents was analyzed by SmartPLS 3.2.8. The results indicated that the features of social media including availability and symbol variety had the significant influences on their work efficiency through work-oriented usage of social media. Publicness and symbol variety had impact on work efficiency via social-oriented usage of social media. In addition, both social media for work-oriented and social-oriented usage influenced employees\' work efficiency. There were different considerations when people selected social media for work or for social purpose. Managers or companies could guide their employees to use the social media in a right way to increase their work features to complete their work efficiency, and create groups for employees so the work information could be shared efficiently.
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  • 文章类型: Journal Article
    In this paper, we discuss fitness landscape evolution of permanent replicator systems applying the hypothesis that the specific time of evolutionary adaptation of system parameters is much slower than the time of internal evolutionary dynamics. In other words, we suppose that the extremal principle of Darwinian evolution based on Fisher\'s fundamental theorem of natural selection is valid for the steady-states of permanent replicator systems. Various cases illustrating this concept are considered.
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  • 文章类型: Journal Article
    The world of uncertainty motivates the study of stochastic perturbation in the mathematical models of real life. The main objective of this paper is to study stochastic sex-structured HIV/AIDS epidemic model with effect of screening of infectives. We have shown that the proposed stochastic epidemic model with boundedness and permanence has a unique global positive solution. The selection of suitable Lyapunov functions provides sufficient conditions for investigating persistence and extinction of disease. Based on numerical experiments, the theoretical findings of this paper have been verified.
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  • 文章类型: Journal Article
    Biodiversity offsetting is the practice of using conservation actions, such as habitat restoration, management, or protection, to compensate for ecological losses caused by development activity, including construction projects. The typical goal of offsetting is no net loss (NNL), which means that all ecological losses are compensated for by commensurate offset gains. We focused on a conceptual and methodological exploration of net positive impact (NPI), an ambitious goal that implies commitment beyond NNL and that has recently received increasing attention from big business and environmental nongovernmental organizations. We identified 3 main ways NPI could be delivered: use of an additional NPI multiplier; use of slowly developing permanent offsets to deliver additional gains after NNL has first been reached during a shorter offset evaluation time interval; and the combination of permanent offsets with partially temporary losses. An important and novel variant of the last mechanism is the use of an alternate mitigation hierarchy so that gains from the traditional third step of the mitigation hierarchy (i.e., onsite rehabilitation) are no longer be counted toward reduced offset requirements. The outcome from these 3 factors is that for the same ecological damage, larger offsets will be required than previously, thereby improving offset success. As a corollary, we show that offsets are NNL only at 1 ephemeral point in time, before which they are net negative and after which they become either NPI or net negative impact, depending on whether permanent offsets are combined with partially temporary losses or if temporary offset gains are combined with partially permanent losses. To achieve NPI, offsets must be made permanent, and they must achieve NNL during an agreed-upon offset evaluation period. An additional NPI-multiplier and use of the modified mitigation hierarchy will deliver additional NPI gains. Achieving NPI is fully conditional on prior achievement of NNL, and NNL offsets have been frequently observed to fail due to inadequate policy requirements, poor planning, or incomplete implementation. Nevertheless, achieving NPI becomes straightforward if NNL can be credibly reached first.
    Tres Maneras de Proporcionar un Impacto Positivo Neto con Compensaciones por Biodiversidad Resumen La compensación por biodiversidad es una práctica que consiste en usar las acciones de conservación, como la restauración, manejo o protección del hábitat, para compensar las pérdidas ecológicas causadas por las actividades de desarrollo, incluidos los proyectos de construcción. La meta típica de la compensación es la nula pérdida neta (NNL), lo que implica que todas las pérdidas ecológicas están compensadas por las ganancias proporcionales. Nos enfocamos en una exploración conceptual y metodológica del impacto positivo neto (NPI), una meta ambiciosa que implica un compromiso más allá de la NNL y que recientemente ha recibido una mayor atención por parte de los grandes negocios y las organizaciones no gubernamentales ambientales. Identificamos tres maneras principales mediante las cuales se podría proporcionar el NPI: el uso de un multiplicador adicional de NPI; el uso de compensaciones permanentes de lento desarrollo para entregar ganancias adicionales después de que primero se haya logrado el NNL durante un intervalo de tiempo más corto para la evaluación de las compensaciones; y la combinación de las compensaciones permanentes con las pérdidas parcialmente temporales. Una variante importante y novedosa del último mecanismo es el uso de una jerarquía alterna de mitigación de tal manera que las ganancias provenientes del tradicional tercer paso de la jerarquía de mitigación (es decir, la rehabilitación in situ) ya no se contabilizan para los requerimientos reducidos de las compensaciones. El resultado de estos tres factores consiste en que para el mismo daño ecológico se requerirán compensaciones mayores a las necesarias previamente, aumentando así el éxito de las compensaciones. Como corolario, demostramos que las compensaciones sólo alcanzan el NNl durante un punto efímero en el tiempo, antes del cual tienen un saldo neto negativo y después del cual se transforman en un impacto neto positivo o un impacto neto negativo dependiendo de si las compensaciones permanentes se combinan con pérdidas parcialmente temporales o de si las ganancias temporales de las compensaciones se combinan con pérdidas parcialmente temporales. Para alcanzar el NPI, las compensaciones deben volverse permanentes y deben llegar al NNL durante un periodo acordado de evaluación de compensaciones. El uso de un multiplicador adicional de NPI y de una jerarquía alterada de mitigación proporcionará ganancias adicionales al NPI. La obtención del NPI es completamente dependiente de la obtención previa del NNL; se ha observado con frecuencia que las compensaciones por NNL fallan debido a los requerimientos inadecuados de las políticas, la pobre planeación o la implementación incompleta. Sin embargo, llegar al NPI se vuelve una tarea sencilla si primero se puede alcanzar el NNL de manera verosímil.
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