共查询到20条相似文献,搜索用时 15 毫秒
1.
Peter Smittenaar Robb B. Rutledge Peter Zeidman Rick A. Adams Harriet Brown Glyn Lewis Raymond J. Dolan 《PloS one》2015,10(10)
One expression of executive control involves proactive preparation for future events, and this contrasts with stimulus driven reactive control exerted in response to events. Here we describe findings from a response inhibition task, delivered using a smartphone-based platform, that allowed us to index proactive and reactive inhibitory self-control in a large community sample (n = 12,496). Change in stop-signal reaction time (SSRT) when participants are provided with advance information about an upcoming trial, compared to when they are not, provides a measure of proactive control while SSRT in the absence of advance information provides a measure of reactive control. Both forms of control rely on overlapping frontostriatal pathways known to deteriorate in healthy aging, an age-related decline that occurs at an accelerated rate in men compared to women. Here we ask whether these patterns of age-related decline are reflected in similar changes in proactive and reactive inhibitory control across the lifespan. As predicted, we observed a decline in reactive control with natural aging, with a greater rate of decline in men compared to women (~10 ms versus ~8 ms per decade of adult life). Surprisingly, the benefit of preparation, i.e. proactive control, did not change over the lifespan and women showed superior proactive control at all ages compared to men. Our results suggest that reactive and proactive inhibitory control partially rely on distinct neural substrates that are differentially sensitive to age-related change. 相似文献
2.
Thompson MV 《Trends in plant science》2006,11(1):26-32
The structure of phloem sieve-element-companion-cell complexes reflects a duality of function: to conduct photoassimilates throughout the plant, and to exchange solutes between the phloem and surrounding tissues. The conceptual integration of these long- and short-distance functions requires the abandonment of a long-cherished concept in phloem physicochemistry, that source-sink turgor differentials control flow. The manifest inability of decentralized organisms such as plants to control phloem translocation centrally disqualifies such differentials as control variables; besides, the phloem is maximally efficient if the pressure differentials are small. Testing this hypothesis and whether turgor differentials are small will require a significant recommitment to studying the quantitative anatomy of phloem. 相似文献
3.
Romanov SP Aleksanian ZA Manoĭlov VV 《Rossi?skii fiziologicheski? zhurnal imeni I.M. Sechenova / Rossi?skaia akademiia nauk》2002,88(10):1356-1368
With the aid of tensotremorography, a voluntary effort was recorded and characteristics of involuntary and voluntary components of the hands' isometrically recorded efforts were studied. The revealed frequency ranges of the oscillations spectral density's changes corroborate existence of two suprasegmental systems of movements control, the systems being related to voluntary control and a current control of the efforts maintaining or preserving a posture. Results of cross-correlation analysis of the hands' efforts maintained under conditions of a visual feedback are demonstrated in norm and in central disorders of the movement control system. 相似文献
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Hardin PE 《Journal of biological rhythms》2004,19(5):348-360
6.
Mathematical studies on the sterile insect technique for the Chikungunya disease and Aedes albopictus 总被引:1,自引:0,他引:1
Chikungunya is an arthropod-borne disease caused by the Asian tiger mosquito, Aedes albopictus. It can be an important burden to public health and a great cause of morbidity and, sometimes, mortality. Understanding if and when disease control measures should be taken is key to curtail its spread. Dumont and Chiroleu (Math Biosc Eng 7(2):315-348, 2010) showed that the use of chemical control tools such as adulticide and larvicide, and mechanical control, which consists of reducing the breeding sites, would have been useful to control the explosive 2006 epidemic in Réunion Island. Despite this, chemical control tools cannot be of long-time use, because they can induce mosquito resistance, and are detrimental to the biodiversity. It is therefore necessary to develop and test new control tools that are more sustainable, with the same efficacy (if possible). Mathematical models of sterile insect technique (SIT) to prevent, reduce, eliminate or stop an epidemic of Chikungunya are formulated and analysed. In particular, we propose a new model that considers pulsed periodic releases, which leads to a hybrid dynamical system. This pulsed SIT model is coupled with the human population at different epidemiological states in order to assess its efficacy. Numerical simulations for the pulsed SIT, using an appropriate numerical scheme are provided. Analytical and numerical results indicate that pulsed SIT with small and frequent releases can be an alternative to chemical control tools, but only if it is used or applied early after the beginning of the epidemic or as a preventive tool. 相似文献
7.
This paper considers the numerical approximation for the optimal supporting position and related optimal control of a catalytic reaction system with some control and state constraints, which is governed by a nonlinear partial differential equations with given initial and boundary conditions. By the Galerkin finite element method, the original problem is projected into a semi-discrete optimal control problem governed by a system of ordinary differential equations. Then the control parameterization method is applied to approximate the control and reduce the original system to an optimal parameter selection problem, in which both the position and related control are taken as decision variables to be optimized. This problem can be solved as a nonlinear optimization problem by a particle swarm optimization algorithm. The numerical simulations are given to illustrate the effectiveness of the proposed numerical approximation method. 相似文献
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Pin-Hui Lee Han Fu Ting-Chun Lai Chen-Yuan Chiang Chang-Chuan Chan Hsien-Ho Lin 《PLoS medicine》2016,13(8)
BackgroundDiabetes is a well-known risk factor for tuberculosis (TB) and is increasingly prevalent in low- and middle-income countries, where the burden of TB is high. Glycemic control has the potential to modify the risk of TB. However, there are few studies on the association between glycemic control and TB risk, and the results are inconsistent.ConclusionsGood glycemic control could potentially modify the risk of TB among diabetic patients and may contribute to the control of TB in settings where diabetes and TB are prevalent. 相似文献
10.
Cystic echinococcosis (CE) is an important zoonosis in Italy and in the whole Mediterranean Region, as confirmed by the work by Ettore Biocca, whose contributions to the subject are reported in a summarised annex to the bibliography. The contribution to the understanding and control of CE are presented, with special emphasis on the socio-economic impact, on factors affecting the maintenance of CE in the Mediterranean Region, on the epidemiological situation and control measures, on the present status of epidemiological surveillance, on the control problems in normal and emergency situations, on health education and training. Also, the justifications of combined control programmes are discussed, which may be applied only in situations of peace and well-being. 相似文献
11.
J. H. M. van Dijk 《Biological cybernetics》1978,30(4):195-208
The problem of the control of voluntary human movements is considered from a cybernetic point of view. The human motor system is considered to be divided into a central part and a peripheral part. The peripheral part is relatively well known and may be regarded as a set of subsystems with well known input-output relations. The interaction between the peripheral part and the central part is related to the mechanisms of the peripheral motor part. With regard to the central part two different types of control mechanisms are possible, a) an intricate functioning of the central part which generates the control signals with regard to internal and external dynamical factors, b) the central part has some degree of independence with respect to the dynamics of the peripheral mortor part. In the latter case the central part prescribes the desired movement exactly, but the final performance of the movement is also brought about by peripheral feedback mechanisms. As a functional form of the interaction between the central part and the peripheral part it might be that the control signals are encoded in a way that is related to the muscle lengths. 相似文献
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Lord JC 《Journal of invertebrate pathology》2005,89(1):19-29
In 125 years since Metchnikoff proposed the use of Metarhizium anisopliae to control the wheat cockchafer and brought about the first field trials, microbial control has progressed from the application of naturalists' observations to biotechnology and precision delivery. This review highlights major milestones in its evolution and presents a perspective on its current direction. Fungal pathogens, the most eye-catching agents, dominated the early period, but major mycological control efforts for chinch bugs and citrus pests in the US had questionable success, and interest waned. The discoveries of Bacillus popilliae and Bacillus thuringiensis began the era of practical and commercially viable microbial control. A program to control the Japanese beetle in the US led to the discovery of both B. popilliae and Steinernema glaseri, the first nematode used as a microbial control agent. Viral insect control became practical in the latter half of the 20th century, and the first registration was obtained with the Heliothis nuclear polyhedrosis virus in 1975. Now strategies are shifting for microbial control. While Bt transgenic crops are now planted on millions of hectares, the successes of more narrowly defined microbial control are mainly in small niches. Commercial enthusiasm for traditional microbial control agents has been unsteady in recent years. The prospects of microbial insecticide use on vast areas of major crops are now viewed more realistically. Regulatory constraints, activist resistance, benign and efficacious chemicals, and limited research funding all drive changes in focus. Emphasis is shifting to monitoring, conservation, integration with chemical pesticides, and selection of favorable venues such as organic agriculture and countries that have low costs, mild regulatory climates, modest chemical inputs, and small scale farming. 相似文献
14.
Summary In this paper, a preliminary concept on the interplay of local, regional and global control factors of bryozoan diversity
and distribution pattern is introduced. Recent bryozoans from the Philippines, New Zealand and the Gulf of Aqaba are compared
to the selected fossil specimens from the Oxfordian and Santonian.
Reef bryozoan skeletons are studied in order to separate local control within the substrate-water interface from regional
control. The latter originate mainly from the transport function of the water column (e.g. sediment load, wave energy, vagile
predators). This is true especially for erect (tree-like) and massive (multilaminar) bryozoans which are subjected to the
dynamics of the water body in the littoral area. This regional control, affects simultaneously several structural and substrate
zones of a reef. Early life history of vertically growing reef bryozoans reflect local control, while older zoarial structures
reflect the signals of regional influence. Three types of multiserial nodular bryozoans are cited: self-overgrowing sheets
(‘S-Nodule’, derived from ‘S-Sheet’), circumlaterally budding colonies (‘C-Nodules’), and fungiform bryozoans.
Bryozoan growth form selection allows the separation of two types of regional controls, long range control which favours the
selection of specialized sheets, and slow rate control documented in the growth form modification of sheets changing into
nodules.
In the domain of local control epibiontic microorganisms, microbial mats and biofilms on hard substrata represent probably
the most important elements, aside from the limited substrate space. Symbiotic and/or competitive bryozoan-microorganism interrelationships
result in the distinct adaptations of bryozoan growth. It is apparent that bryozoan modifications of substrate micro-topography
influence the character of epibiontic microbial settlement. The peak occurrence of microbial settlement on prominent external
bryozoan skeleton parts is discussed as an effect of feeding currents. In contrast, smooth and unelevated exoskeletons are
less favourable for micro-epibiontic colonization. Due to the high level of order in the spatial zonation patterns of epibionts
on calcifying bryozoans, the term ‘bryozoan-microreef’ is introduced. Bryozoan-microreefs are locally controlled reefs. They
are e.g. characterized by higher competitive abilities than bryozoans without ‘reefdwellers’. Local control has a fast rate
of change and is reflected in morphologies of individual zooids and/or single zooid generations.
Regional control has a slower rate but a higher range. It is important for growth modifications of the whole zoaria. The very
slow rate of global control cannot be recorded within the life span of bryozoan zoaria unless it is expressed through regional
control (such as monsoons). Nevertheless, global control is paleoecologically important because it is traceable in bryozoan
(paleo-)biogeography. For practical purpose, we suggest to define those control factors of bryozoans as global which affect
simultaneously at least one tropical and one non-tropical bryozoan community.
This reportis dedicated to the memory of our friend and research colleague Mr. Joselito G. Santiago of the University of San
Carlos, Marine Biology Section. Tiago (as we fondly call him) has started within the scope of the Philippine Bryozoan Project
an applied research on fish abundance and productivity around a new artificial reef model. This prototype model was conceptualized
with him. His promising study remained unfinished; he died May 13, 1993, while sampling inside the reef cave off Marigondon. 相似文献
15.
P E Rapp 《Biology of reproduction》1985,32(1):70-72
Two statements will be presented and defended in this paper. First, it is claimed that oscillations are common in all biological systems. From the subcellular to the organismic levels of organization, oscillations are the normal operational mode for many biochemical and physiological control networks. Second, it will be demonstrated that periodic control offers several functional advantages over steady-state control. 相似文献
16.
国际蝗虫灾害的防治策略和技术:现状与展望 总被引:12,自引:3,他引:12
简要地综述了国际上对蝗虫灾害管理策略与控制技术的发展现状,包括:监测与预警技术、化学防治、生物防治、综合管理对策以及目前的研究热点方向。比较分析了国际、国内蝗虫发生及其治理中存在问题的异同。国际上控制蝗虫灾害的理论、技术、措施、对策,对中国有重要的借鉴作用。一般来说, 控制蝗虫灾害的IPM计划中应该包括:在策略上,强调提前预防压制优于后期灭杀处理;在规律认识上,重视基础生物学和生态学的研究,并将之模型化和标准化;在测报方法上,积极发展和改善监测预警技术水平,将地理信息系统(GIS)和遥感(RS)技术集成引入到防治决策的整体系统中,使信息能够快速、准确地传递;在防治手段上,注意新型防治药剂和施药技术的研究开发和集成,增加用药效果;在天敌利用和环境保护方面,充分认识和评估自然天敌的控制作用,正确地估计防治效益和挽回的损失,重视对环境价值的评价;同时加强多个地区间的联合与协调。 相似文献
17.
Methods currently used for the control of anaplasmosis and babesiosis: their validity and proposals for future control strategies 总被引:1,自引:0,他引:1
Four alternative approaches to the control of anaplasmosis and babesiosis as a complex of diseases are identified: no active control, tick control, immunization, and chemoprophylaxis. These methods may be utilized in one of five strategies: tick eradication with or without concurrent immunization, tick reduction with or without concurrent immunization or no active control. Factors influencing the choice of strategy are discussed. 相似文献
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19.
Mao L 《PloS one》2011,6(10):e24706
Control strategies enforced by health agencies are a major type of practice to contain influenza outbreaks. Another type of practice is the voluntary preventive behavior of individuals, such as receiving vaccination, taking antiviral drugs, and wearing face masks. These two types of practices take effects concurrently in influenza containment, but little attention has been paid to their combined effectiveness. This article estimates this combined effectiveness using established simulation models in the urbanized area of Buffalo, NY, USA. Three control strategies are investigated, including: Targeted Antiviral Prophylaxis (TAP), workplace/school closure, community travel restriction, as well as the combination of the three. All control strategies are simulated with and without regard to individual preventive behavior, and the resulting effectiveness are compared. The simulation outcomes suggest that weaker control strategies could suffice to contain influenza epidemics, because individuals voluntarily adopt preventive behavior, rendering these weaker strategies more effective than would otherwise have been expected. The preventive behavior of individuals could save medical resources for control strategies and avoid unnecessary socio-economic interruptions. This research adds a human behavioral dimension into the simulation of control strategies and offers new insights into disease containment. Health policy makers are recommended to review current control strategies and comprehend preventive behavior patterns of local populations before making decisions on influenza containment. 相似文献
20.
Gastrulation movements: the logic and the nuts and bolts 总被引:1,自引:0,他引:1
Leptin M 《Developmental cell》2005,8(3):305-320