WorldWideScience

Sample records for bottlenecks

  1. Logistics bottlenecks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-09-15

    Many of the vulnerabilities to Energy Access, Energy Security, and Environmental Sustainability result from impediments to reaching a global demand-supply balance, as well as local balances, for various energy sources and carriers. Vulnerabilities result from multiple reasons: regional imbalances of energy production and consumption, the bulky character of the majority of energy fuels, the virtual necessity of electricity consumption following its production, among others. To detect and prioritize respective 'bottlenecks' across energy carriers, they have to be measured. In this report, production, consumption, exports, and imports were measured across all major energy carriers for seven key regions of the world for three time frames-2008, 2020, and 2050. Imbalances between production and consumption form bottlenecks in each region.

  2. When is a bottleneck a bottleneck?

    CERN Document Server

    Schadschneider, Andreas; Popkov, Vladislav

    2015-01-01

    Bottlenecks, i.e. local reductions of capacity, are one of the most relevant scenarios of traffic systems. The asymmetric simple exclusion process (ASEP) with a defect is a minimal model for such a bottleneck scenario. One crucial question is "What is the critical strength of the defect that is required to create global effects, i.e. traffic jams localized at the defect position". Intuitively one would expect that already an arbitrarily small bottleneck strength leads to global effects in the system, e.g. a reduction of the maximal current. Therefore it came as a surprise when, based on computer simulations, it was claimed that the reaction of the system depends in non-continuous way on the defect strength and weak defects do not have a global influence on the system. Here we reconcile intuition and simulations by showing that indeed the critical defect strength is zero. We discuss the implications for the analysis of empirical and numerical data.

  3. Bottleneck flows in networks

    CERN Document Server

    Punnen, Abraham P

    2007-01-01

    The bottleneck network flow problem (BNFP) is a generalization of several well-studied bottleneck problems such as the bottleneck transportation problem (BTP), bottleneck assignment problem (BAP), bottleneck path problem (BPP), and so on. In this paper we provide a review of important results on this topic and its various special cases. We observe that the BNFP can be solved as a sequence of $O(\\log n)$ maximum flow problems. However, special augmenting path based algorithms for the maximum flow problem can be modified to obtain algorithms for the BNFP with the property that these variations and the corresponding maximum flow algorithms have identical worst case time complexity. On unit capacity network we show that BNFP can be solved in $O(\\min \\{{m(n\\log n)}^{{2/3}}, m^{{3/2}}\\sqrt{\\log n}\\})$. This improves the best available algorithm by a factor of $\\sqrt{\\log n}$. On unit capacity simple graphs, we show that BNFP can be solved in $O(m \\sqrt {n \\log n})$ time. As a consequence we have an $O(m \\sqrt {n \\l...

  4. Estimating Bottleneck Bandwidth using TCP

    Science.gov (United States)

    Allman, Mark

    1998-01-01

    Various issues associated with estimating bottleneck bandwidth using TCP are presented in viewgraph form. Specific topics include: 1) Why TCP is wanted to estimate the bottleneck bandwidth; 2) Setting ssthresh to an appropriate value to reduce loss; 3) Possible packet-pair solutions; and 4) Preliminary results: ACTS and the Internet.

  5. Effects of Bottlenecks in Vehicle Traffic

    CERN Document Server

    Yamamoto, S; Tadaki, S; Yamamoto, Syohei; Hieida, Yasuhiro; Tadaki, Shin-ichi

    2006-01-01

    Traffic congestion is usually observed at the upper streams of bottlenecks like tunnels. Congestion appears as stop-and-go waves and high density uniform flow. We perform simulations of traffic flow with a bottleneck using the coupled map optimal velocity model. The bottleneck is expressed as a road segment with speed reduction. The emergence of stop-and-go waves depends on the speed reduction in the bottleneck. A phenomenological theory of bottleneck effects is constructed.

  6. Mitigating SDN controller performance bottlenecks

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius; Soler, José

    2015-01-01

    proposes a new approach for addressing the performance bottlenecks that arise from limited computational resources at the SDNC. The proposed approach is based on optimally configuring the operating parameters of the components residing inside the SDNC (network control functions such as monitoring, routing...

  7. Sales bottlenecks and their effect on profit

    NARCIS (Netherlands)

    Veltman, M.; Kooij, R.E.; Marban, S.

    2014-01-01

    This study introduces the term sales bottleneck, defined as a stage in a total production or service delivery process that limits sales. After analyzing the suitability of traditional methods to find sales bottlenecks, the study proposes the bottleneck accounting model as a method to determine sales

  8. MODIFIED BOTTLENECK-BASED PROCEDURE FOR LARGE-SCALE FLOW-SHOP SCHEDULING PROBLEMS WITH BOTTLENECK

    Institute of Scientific and Technical Information of China (English)

    ZUO Yan; GU Hanyu; XI Yugeng

    2006-01-01

    A new bottleneck-based heuristic for large-scale flow-shop scheduling problems with a bottleneck is proposed, which is simpler but more tailored than the shifting bottleneck (SB)procedure. In this algorithm, a schedule for the bottleneck machine is first constructed optimally and then the non-bottleneck machines are scheduled around the bottleneck schedule by some effective dispatching rules. Computational results show that the modified bottleneck-based procedure can achieve a tradeoff between solution quality and computational time comparing with SB procedure for medium-size problems. Furthermore it can obtain a good solution in quite short time for large-scale scheduling problems.

  9. Dynamic Prediction Method of Production Logistics Bottleneck Based on Bottleneck Index

    Institute of Scientific and Technical Information of China (English)

    LIU Mingzhou; TANG Juan; GE Maogen; JIANG Zengqiang; HU Jing; LING Lin

    2009-01-01

    In modern manufacturing pattern, there are many uncertain factors in the modern manufacturing process, such as changes of product attribute, changes of manufacturing resources' state, and so on, which cause production logistics bottleneck frequently shift, and make decisions of production planning and control based on formed bottleneck deviated from practical production process. Considering these factors, present researches mainly apply afterwards control to optimize production process to passively adapt to bottleneck changes. If the direction of bottleneck shifting can be accurately forecasted, the transition from afterwards control of chasing bottleneck to beforehand control can be realized. Therefore, aiming at the phenomenon of production logistics bottleneck shifting under uncertain manufacturing circumstances, this paper starts off with dynamic property of capability and requirement and then builds the concepts of bottleneck degree and bottleneck index to describe dynamic bottleneck characteristic of production unit;taken production capability, production load and quality assurance capability into consideration, mathematical model of bottleneck index is established to measure bottleneck degree accurately, consequently, quantitative research on mechanism of production logistics shifting is achieved. Based on bottleneck index, the prediction model of production logistics bottleneck is founded to predict dynamic change of bottleneck accurately. Finally, an example of forecasting and monitoring the production logistics bottleneck in one manufacturing shop is given to testify the validation and practicability of the prediction method.

  10. BOTTLENECKS IN PRODUCTION NETWORKS: AN OVERVIEW

    Institute of Scientific and Technical Information of China (English)

    Yongcai WANG; Qianchuan ZHAO; Dazhong ZHENG

    2005-01-01

    Bottlenecks, the key ingredients for improving the performances of the production networks,have been profoundly studied during the last decade. Yet, because of the complexity of the research results, there is still a significant gap between theory and practice. In this paper, we review various bottleneck definitions, detection methods and the asymptotic results and provide a practical guidance for recognizing and utilizing the bottlenecks in production networks. Queueing theory works as the mathematical foundation in our study. Various definitions of the bottlenecks are classified as either Performance in Processing (PIP) based or sensitivity based definitions, which reflect the preferences of the managers. Detection methods are surveyed closely based on the definitions. These methods are used to recognize the bottlenecks and to provide diagnosis results to managers. Comparisons show that different detection methods may lead to vastly different conclusions. The recognition of the bottlenecks has another advantage: the ultimate phenomena of the bottlenecks can greatly reduce the computation complexity in calculating the system performances. Bottlenecks based approximation and asymptotic results are studied to exhibit the contribution of bottlenecks in performance estimation and theoretical analysis.

  11. Large data centers interconnect bottlenecks.

    Science.gov (United States)

    Ghiasi, Ali

    2015-02-09

    Large data centers interconnect bottlenecks are dominated by the switch I/O BW and the front panel BW as a result of pluggable modules. To overcome the front panel BW and the switch ASIC BW limitation one approach is to either move the optics onto the mid-plan or integrate the optics into the switch ASIC. Over the last 4 years, VCSEL based optical engines have been integrated into the packages of large-scale HPC routers, moderate size Ethernet switches, and even FPGA's. Competing solutions based on Silicon Photonics (SiP) have also been proposed for integration into HPC and Ethernet switch packages but with better integration path through the use of TSV (Through Silicon Via) stack dies. Integrating either VCSEL or SiP based optical engines into complex ASIC package that operates at high temperatures, where the required reliability is not trivial, one should ask what is the technical or the economic advantage before embarking on such a complex integration. High density Ethernet switches addressing data centers currently in development are based on 25G NRZ signaling and QSFP28 optical module that can support up to 3.6 Tb of front panel bandwidth.

  12. Analytical approach to continuous and intermittent bottleneck flows

    DEFF Research Database (Denmark)

    Helbing, D.; Johansson, A.; Mathiesen, Joachim Kaj;

    2006-01-01

    Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20......Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20...

  13. Cloud Technology May Widen Genomic Bottleneck - TCGA

    Science.gov (United States)

    Computational biologist Dr. Ilya Shmulevich suggests that renting cloud computing power might widen the bottleneck for analyzing genomic data. Learn more about his experience with the Cloud in this TCGA in Action Case Study.

  14. Anticipation Behavior Upstream of a Bottleneck

    NARCIS (Netherlands)

    Duives, D.C.; Daamen, W.; Hoogendoorn, S.P.

    2014-01-01

    Whether pedestrian movements do or do not follow similar patterns as vehicular traffic while experiencing congestion is not entirely understood. Using data gathered during bottleneck experiments under laboratory conditions, the phenomenon of anticipation before entering congestion is studied. This p

  15. Urban traffic congestion propagation and bottleneck identification

    Institute of Scientific and Technical Information of China (English)

    LONG JianCheng; GAO ZiYou; REN HuaLing; LIAN AiPing

    2008-01-01

    Bottlenecks in urban traffic network are sticking points in restricting network col-lectivity traffic efficiency.To identify network bottlenecks effectively is a founda-tional work for improving network traffic condition and preventing traffic conges-tion.In this paper,a congestion propagation model of urban network traffic is proposed based on the cell transmission model (CTM).The proposed model in-cludes a link model,which describes flow propagation on links,and a node model,which represents link-to-link flow propagation.A new method of estimating average journey velocity (AJV) of both link and network is developed to identify network congestion bottlenecks.A numerical example is studied in Sioux Falls urban traffic network.The proposed model is employed in simulating network traffic propaga-tion and congestion bottleneck identification under different traffic demands.The simulation results show that continual increase of traffic demand is an immediate factor in network congestion bottleneck emergence and increase as well as re-ducing network collectivity capability.Whether a particular link will become a bot-tleneck is mainly determined by its position in network,its traffic flow (attributed to different OD pairs) component,and network traffic demand.

  16. Potential performance bottleneck in Linux TCP

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenji; Crawford, Matt; /Fermilab

    2006-12-01

    TCP is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid-task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system to its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modeling and practical experiments; finally we propose and test one possible solution to resolve this performance bottleneck in Linux TCP.

  17. The Simulation Utilization for the Bottleneck Identification

    Directory of Open Access Journals (Sweden)

    Petra Vegnerová

    2009-12-01

    Full Text Available Advancing globalization increasingly leads to the creation of delivery systems. Increasing competition forces companies to reduce costs permanently. Both of these trends lead to the need to control material and information flows precisely. The target of this article is to describe and show one of ways of bottleneck determination in the supply system. This study deals with the computer simulation and its utilization for assessment of bottleneck. The foundation of the work is created a model of the supply system, it is used to compare the costs associated with the existence of stocks and stock levels in the individual partner of the system, depending on the location of the bottleneck. This article is published as a part of the research intention MSM 6046137306.

  18. Properties of Bottleneck on Complex Networks

    Institute of Scientific and Technical Information of China (English)

    WANG Chao-Yang; WU Jian-Jun; GAO Zi-You

    2011-01-01

    The traffic bottleneck plays a key role in most of the natural and artificial network.Here we present a simply model for bottleneck dynamical characteristics consideration the reliability on the complex network by taking into account the network topology characteristics and system size.We find that there is a critical rate of flow generation below which the network traffic is free but above which traffic congestion occurs.Also, it is found that random networks have larger critical flow generating rate than scale free ones.Analytical results may be practically useful for designing networks, especially for the urban traffic network.

  19. Reliability of genetic bottleneck tests for detecting recent population declines

    NARCIS (Netherlands)

    Peery, M. Zachariah; Kirby, Rebecca; Reid, Brendan N.; Stoelting, Ricka; Doucet-Beer, Elena; Robinson, Stacie; Vasquez-Carrillo, Catalina; Pauli, Jonathan N.; Palsboll, Per J.

    2012-01-01

    The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popula

  20. Individual Microscopic Results Of Bottleneck Experiments

    CERN Document Server

    Bukáček, Marek; Krbálek, Milan

    2016-01-01

    This contribution provides microscopic experimental study of pedestrian motion in front of the bottleneck, explains the high variance of individual travel time by the statistical analysis of trajectories. The analysis shows that this heterogeneity increases with increasing occupancy. Some participants were able to reach lower travel time due more efficient path selection and more aggressive behavior within the crowd. Based on this observations, linear model predicting travel time with respect to the aggressiveness of pedestrian is proposed.

  1. Bottleneck effects on the bidirectional crowd dynamics

    Science.gov (United States)

    Yang, Xiao-Xia; Dong, Hai-Rong; Yao, Xiu-Ming; Sun, Xu-Bin

    2016-12-01

    The bottleneck effect on bidirectional crowd dynamics is of great theoretical and practical significance, especially for the designing of corridors in public places, such as subway stations or airports. Based on the famous social force model, this paper investigates the bottleneck effects on the free flow dynamics and breakdown phenomenon under different scenarios, in which different corridor shapes and inflow ratios are considered simultaneously. Numerical simulation finds an interesting self-organization phenomenon in the bidirectional flow, a typical characteristic of such a phenomenon is called lane formation, and the existence of which is independent of the corridor’s shape and inflow rate. However, the pattern of the lane formed by pedestrian flow is related to the corridor’s shape, and the free flow efficiency has close relationship with the inflow rate. Specifically, breakdown phenomenon occurs when inflows from both sides of the corridor are large enough, which mostly originates from the bottleneck and then gradually spreads to the other regions. Simulation results further indicate that the leaving efficiency becomes low as breakdown occurs, and the degree of congestion is proportional to the magnitude of inflow. The findings presented in this paper match well with some of our daily observations, hence it is possible to use them to provide us with theoretical suggestions in design of infrastructures. Project supported jointly by the National Natural Science Foundation of China (Grant Nos. 61322307 and 2016YJS023).

  2. Bottlenecks to coral recovery in the Seychelles

    Science.gov (United States)

    Chong-Seng, K. M.; Graham, N. A. J.; Pratchett, M. S.

    2014-06-01

    Processes that affect recovery of coral assemblages require investigation because coral reefs are experiencing a diverse array of more frequent disturbances. Potential bottlenecks to coral recovery include limited larval supply, low rates of settlement, and high mortality of new recruits or juvenile corals. We investigated spatial variation in local abundance of scleractinian corals in the Seychelles at three distinct life history stages (recruits, juveniles, and adults) on reefs with differing benthic conditions. Following widespread coral loss due to the 1998 bleaching event, some reefs are recovering (i.e., relatively high scleractinian coral cover: `coral-dominated'), some reefs have low cover of living macrobenthos and unconsolidated rubble substrates (`rubble-dominated'), and some reefs have high cover of macroalgae (`macroalgal-dominated'). Rates of coral recruitment to artificial settlement tiles were similar across all reef conditions, suggesting that larval supply does not explain differential coral recovery across the three reef types. However, acroporid recruits were absent on macroalgal-dominated reefs (0.0 ± 0.0 recruits tile-1) in comparison to coral-dominated reefs (5.2 ± 1.6 recruits tile-1). Juvenile coral colony density was significantly lower on macroalgal-dominated reefs (2.4 ± 1.1 colonies m-2), compared to coral-dominated reefs (16.8 ± 2.4 m-2) and rubble-dominated reefs (33.1 ± 7.3 m-2), suggesting that macroalgal-dominated reefs have either a bottleneck to successful settlement on the natural substrates or a high post-settlement mortality bottleneck. Rubble-dominated reefs had very low cover of adult corals (10.0 ± 1.7 %) compared to coral-dominated reefs (33.4 ± 3.6 %) despite no statistical difference in their juvenile coral densities. A bottleneck caused by low juvenile colony survivorship on unconsolidated rubble-dominated reefs is possible, or alternatively, recruitment to rubble-dominated reefs has only recently begun. This

  3. A theory of traffic congestion at moving bottlenecks

    Science.gov (United States)

    Kerner, Boris S.; Klenov, Sergey L.

    2010-10-01

    The physics of traffic congestion occurring at a moving bottleneck on a multi-lane road is revealed based on the numerical analyses of vehicular traffic with a discrete stochastic traffic flow model in the framework of three-phase traffic theory. We find that there is a critical speed of a moving bottleneck at which traffic breakdown, i.e. a first-order phase transition from free flow to synchronized flow, occurs spontaneously at the moving bottleneck, if the flow rate upstream of the bottleneck is great enough. The greater the flow rate, the higher the critical speed of the moving bottleneck. A diagram of congested traffic patterns at the moving bottleneck is found, which shows regions in the flow-rate-moving-bottleneck-speed plane in which congested patterns emerge spontaneously or can be induced through large enough disturbances in an initial free flow. A comparison of features of traffic breakdown and resulting congested patterns at the moving bottleneck with known ones at an on-ramp (and other motionless) bottleneck is made. Nonlinear features of complex interactions and transformations of congested traffic patterns occurring at on- and off-ramp bottlenecks due to the existence of the moving bottleneck are found. The physics of the phenomenon of traffic congestion due to 'elephant racing' on a multi-lane road is revealed.

  4. Identification and optimization of traffic bottleneck with signal timing

    Directory of Open Access Journals (Sweden)

    Shaoxin Yuan

    2014-10-01

    Full Text Available In urban transportation network, traffic congestion is likely to occur at traffic bottlenecks. The signal timing at intersections together with static properties of left-turn and straight-through lanes of roads are two significant factors causing traffic bottlenecks. A discrete-time model of traffic bottleneck is hence developed to analyze these two factors, and a bottleneck indicator is introduced to estimate the comprehensive bottleneck degree of individual road in regional transportation networks universally, the identification approaches are presented to identify traffic bottlenecks, bottleneck-free roads, and bottleneck-prone roads. Based on above work, the optimization method applies ant colony algorithm with effective green time as decision variables to find out an optimal coordinated signal timing plan for a regional network. In addition, a real experimental transportation network is chosen to verify the validation of bottleneck identification. The bottleneck identification approaches can explain the features of occurrence and dissipation of traffic congestion in a certain extent, and the bottleneck optimization method provides a new way to coordinate signal timing at intersections to mitigate traffic congestion.

  5. Document Clustering using Sequential Information Bottleneck Method

    CERN Document Server

    Gayathri, P J; Punithavalli, M

    2010-01-01

    This paper illustrates the Principal Direction Divisive Partitioning (PDDP) algorithm and describes its drawbacks and introduces a combinatorial framework of the Principal Direction Divisive Partitioning (PDDP) algorithm, then describes the simplified version of the EM algorithm called the spherical Gaussian EM (sGEM) algorithm and Information Bottleneck method (IB) is a technique for finding accuracy, complexity and time space. The PDDP algorithm recursively splits the data samples into two sub clusters using the hyper plane normal to the principal direction derived from the covariance matrix, which is the central logic of the algorithm. However, the PDDP algorithm can yield poor results, especially when clusters are not well separated from one another. To improve the quality of the clustering results problem, it is resolved by reallocating new cluster membership using the IB algorithm with different settings. IB Method gives accuracy but time consumption is more. Furthermore, based on the theoretical backgr...

  6. Modified bottleneck-based heuristic for large-scale job-shop scheduling problems with a single bottleneck

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A modified bottleneck-based (MB) heuristic for large-scale job-shop scheduling problems with a welldefined bottleneck is suggested,which is simpler but more tailored than the shifting bottleneck (SB) procedure.In this algorithm,the bottleneck is first scheduled optimally while the non-bottleneck machines are subordinated around the solutions of the bottleneck schedule by some effective dispatching rules.Computational results indicate that the MB heuristic can achieve a better tradeoff between solution quality and computational time compared to SB procedure for medium-size problems.Furthermore,it can obtain a good solution in a short time for large-scale job-shop scheduling problems.

  7. Deep Complementary Bottleneck Features for Visual Speech Recognition

    NARCIS (Netherlands)

    Petridis, Stavros; Pantic, Maja

    2016-01-01

    Deep bottleneck features (DBNFs) have been used successfully in the past for acoustic speech recognition from audio. However, research on extracting DBNFs for visual speech recognition is very limited. In this work, we present an approach to extract deep bottleneck visual features based on deep auto

  8. Deep bottleneck features for spoken language identification.

    Directory of Open Access Journals (Sweden)

    Bing Jiang

    Full Text Available A key problem in spoken language identification (LID is to design effective representations which are specific to language information. For example, in recent years, representations based on both phonotactic and acoustic features have proven their effectiveness for LID. Although advances in machine learning have led to significant improvements, LID performance is still lacking, especially for short duration speech utterances. With the hypothesis that language information is weak and represented only latently in speech, and is largely dependent on the statistical properties of the speech content, existing representations may be insufficient. Furthermore they may be susceptible to the variations caused by different speakers, specific content of the speech segments, and background noise. To address this, we propose using Deep Bottleneck Features (DBF for spoken LID, motivated by the success of Deep Neural Networks (DNN in speech recognition. We show that DBFs can form a low-dimensional compact representation of the original inputs with a powerful descriptive and discriminative capability. To evaluate the effectiveness of this, we design two acoustic models, termed DBF-TV and parallel DBF-TV (PDBF-TV, using a DBF based i-vector representation for each speech utterance. Results on NIST language recognition evaluation 2009 (LRE09 show significant improvements over state-of-the-art systems. By fusing the output of phonotactic and acoustic approaches, we achieve an EER of 1.08%, 1.89% and 7.01% for 30 s, 10 s and 3 s test utterances respectively. Furthermore, various DBF configurations have been extensively evaluated, and an optimal system proposed.

  9. Critical Bottleneck Size for Jamless Particle Flows in Two Dimensions

    Science.gov (United States)

    Masuda, Takumi; Nishinari, Katsuhiro; Schadschneider, Andreas

    2014-04-01

    We propose a simple microscopic model for arching phenomena at bottlenecks. The dynamics of particles in front of a bottleneck is described by a one-dimensional stochastic cellular automaton on a semicircular geometry. The model reproduces oscillation phenomena due to the formation and collapsing of arches. It predicts the existence of a critical bottleneck size for continuous particle flows. The dependence of the jamming probability on the system size is approximated by the Gompertz function. The analytical results are in good agreement with simulations.

  10. A Design Framework for Metaheuristics: Problem Types and Avoiding Bottlenecking

    OpenAIRE

    2006-01-01

    This paper is concerned with an aspect of the design of metaheuristic algorithms, such as evolutionary algorithms, tabu search and ant colony optimization. The topic that is considered is how problems can be represented when they are given to a metaheuristic algorithm. A particular difficulty is presented, viz. the ''bottleneck'', where the problem is artificially converted into a new representation in order to fit the standard input to the metaheuristic. Such bottlenecks cause problems in in...

  11. Bottlenecks in serial production lines: A system-theoretic approach

    Directory of Open Access Journals (Sweden)

    C.-T. Kuo

    1996-01-01

    Full Text Available In this work, a new definition of production systems bottlenecks is formulated and analyzed. Specifically, a machine is defined as the bottleneck if the sensitivity of the system's performance index to this machine's production rate in isolation is the largest. Although appealing from the systems point of view, this definition suffers a deficiency due to the fact that the sensitivities involved cannot be either measured on-line or efficiently calculated off-line. To avoid this, the paper develops a method based on indirect but real-time data. From this point of view, the main result of the work is as follows: The bottleneck machine in a serial production line can be identified by analyzing relationships between the so-called manufacturing blockage and manufacturing starvation of each machine. This leads to a simple rule for bottleneck identification. The rule requires neither the calculation of the production rate sensitivities nor the production rate itself. When the probabilities of manufacturing blockages and starvations are not available from on-line measurements, the paper presents their analytical estimates which, under certain conditions, can be used for bottleneck identification. Finally, a case study at an automotive component plant is described.

  12. Research of Cruise Industry Development Bottlenecks In China

    Directory of Open Access Journals (Sweden)

    Ping Zhou

    2014-08-01

    Full Text Available Cruise industry is a comprehensive new industry, which has a strong impetus to the development of other industries. In recent years, as the explosive growth in cruise market, China has become a global rapidly-growing emerging cruise market. The cruise industry has begun transiting from infancy to the development phase, in all likelihood facing a number of bottlenecks problem. In this paper, the development trend of the cruise industry is first analyzed, then the bottlenecks of cruise industry are studied and finally some reasonable countermeasures and suggestions are put forward. By perfecting policy and legal, expanding industrial chain, diversifying investment mode, cultivating the market of consumer subjects, and establishing a scientific talents training mode of enterprise, the bottlenecks of cruise industry can be solved. This will consequently promote healthy and rapid development in cruise tourism industry, and give full play to the role of joint economy.

  13. c-Bottlenecks in serial production lines: Identification and application

    Directory of Open Access Journals (Sweden)

    Chiang S.-Y.

    2001-01-01

    Full Text Available The bottleneck of a production line is a machine that impedes the system performance in the strongest manner. In production lines with the so-called Markovian model of machine reliability, bottlenecks with respect to the downtime, uptime, and the cycle time of the machines can be introduced. The two former have been addressed in recent publications [1] and [2]. The latter is investigated in this paper. Specifically, using a novel aggregation procedure for performance analysis of production lines with Markovian machines having different cycle time, we develop a method for c-bottleneck identification and apply it in a case study to a camshaft production line at an automotive engine plant.

  14. The "Bottleneck" Behaviours in Linear FNNCs and Their Breakthrough

    Institute of Scientific and Technical Information of China (English)

    HUANG Deshuang

    1999-01-01

    The classification mechanisms of linear feed forward neural network classifiers (FNNC), whose hidden layer performs the Fisher lineartrans formation of the input patterns, under the supervision of outer-supervised signals are investigated. The "bottleneck" behavioursin linear FNNCs are observed and analyzed. In addition, the structure stabilities of the linear FNNCs are also discussed. It is pointed out that the key point to break through the "bottleneck" behaviours forlinear FNNCs is to change linear hidden neurons into nonlinear hiddenones. Finally, the experimental results, taking the parity 3 problem asexample, are given.

  15. Kinetic description of bottleneck effects in traffic flow

    Institute of Scientific and Technical Information of China (English)

    Peng ZHANG; Dong-yan WU; S. C. WONG; Yi-zhou TAO

    2009-01-01

    This paper deals with the effects of traffic bottlenecks using an extended Lighthill-Whitham-Richards (LWR) model. The solution structure is analytically indi-cated by the study of the Riemann problem characterized by a discontinuous flux. This leads to a typical solution describing a queue upstream of the bottleneck and its width and height, and informs the design of a 5-mapping algorithm. More significantly, it is found that the kinetic model is able to reproduce stop-and-go waves for a triangular fun-damental diagram. Some simulation examples, which are in agreement with the analytical solutions, are given to support these conclusions.

  16. Energetic bottlenecks and other design constraints in avian annual cycles

    NARCIS (Netherlands)

    Piersma, T

    2002-01-01

    The flexible phenotypes of birds and mammals often appear to represent adjustments to alleviate some energetic bottleneck or another. By increasing the size of the organs involved in digestion and assimilation of nutrients (gut and liver), an individual bird can increase its ability to process nutri

  17. Mitigating the controller performance bottlenecks in Software Defined Networks

    DEFF Research Database (Denmark)

    Caba, Cosmin Marius; Soler, José

    2016-01-01

    proposes a new approach for addressing the performance bottlenecks that arise from limited computational resources at the SDNC. The proposed approach is based on optimally configuring the operating parameters of the components residing inside the SDNC (network control functions such as monitoring, routing...

  18. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  19. The Case for a Gaian Bottleneck: The Biology of Habitability.

    Science.gov (United States)

    Chopra, Aditya; Lineweaver, Charles H

    2016-01-01

    The prerequisites and ingredients for life seem to be abundantly available in the Universe. However, the Universe does not seem to be teeming with life. The most common explanation for this is a low probability for the emergence of life (an emergence bottleneck), notionally due to the intricacies of the molecular recipe. Here, we present an alternative Gaian bottleneck explanation: If life emerges on a planet, it only rarely evolves quickly enough to regulate greenhouse gases and albedo, thereby maintaining surface temperatures compatible with liquid water and habitability. Such a Gaian bottleneck suggests that (i) extinction is the cosmic default for most life that has ever emerged on the surfaces of wet rocky planets in the Universe and (ii) rocky planets need to be inhabited to remain habitable. In the Gaian bottleneck model, the maintenance of planetary habitability is a property more associated with an unusually rapid evolution of biological regulation of surface volatiles than with the luminosity and distance to the host star.

  20. On the inefficiency of equilibria in linear bottleneck congestion games

    NARCIS (Netherlands)

    Keijzer, B. de; Schäfer, G.; Telelis, O.; Kontogiannis, S.; Koutsoupias, E.; Spirakis, P.G.

    2010-01-01

    We study the inefficiency of equilibrium outcomes in bottleneck congestion games. These games model situations in which strategic players compete for a limited number of facilities. Each player allocates his weight to a (feasible) subset of the facilities with the goal to minimize the maximum (weigh

  1. Step by step: Revisiting step tolling in the bottleneck model

    NARCIS (Netherlands)

    Lindsey, C.R.; Berg, van den V.A.C.; Verhoef, E.T.

    2010-01-01

    In most dynamic traffic congestion models, congestion tolls must vary continuously over time to achieve the full optimum. This is also the case in Vickrey's (1969) 'bottleneck model'. To date, the closest approximations of this ideal in practice have so-called 'step tolls', in which the toll takes o

  2. Population Bottlenecks Increase Additive Genetic Variance But Do Not Break a Selection Limit in Rainforest Drosophila

    DEFF Research Database (Denmark)

    van Heerwaarden, Belinda; Willi, Yvonne; Kristensen, Torsten N;

    2008-01-01

    According to neutral quantitative genetic theory, population bottlenecks are expected to decrease standing levels of additive genetic variance of quantitative traits. However, some empirical and theoretical results suggest that, if nonadditive genetic effects influence the trait, bottlenecks may ...

  3. Bottleneck on Supply Chain of Organic Agricultural Products and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-min

    2012-01-01

    Organic agriculture is one of successful models of low-carbon agriculture, and plays an important role in alleviating and adapting to climate change. However, the development of supply chain of organic agricultural products lags behind, which seriously restricts development of organic agricultural product market. In this paper, major models and bottleneck of supply chain of organic agricultural products are analyzed, and finally countermeasures are put forward.

  4. Linguistics, cognitive psychology, and the Now-or-Never bottleneck.

    Science.gov (United States)

    Endress, Ansgar D; Katzir, Roni

    2016-01-01

    Christiansen & Chater (C&C)'s key premise is that "if linguistic information is not processed rapidly, that information is lost for good" (sect. 1, para. 1). From this "Now-or-Never bottleneck" (NNB), C&C derive "wide-reaching and fundamental implications for language processing, acquisition and change as well as for the structure of language itself" (sect. 2, para. 10). We question both the premise and the consequentiality of its purported implications.

  5. Nonlocal bottleneck effect in two-dimensional turbulence

    CERN Document Server

    Biskamp, D; Schwarz, E

    1998-01-01

    The bottleneck pileup in the energy spectrum is investigated for several two-dimensional (2D) turbulence systems by numerical simulation using high-order diffusion terms to amplify the effect, which is weak for normal diffusion. For 2D magnetohydrodynamic (MHD) turbulence, 2D electron MHD (EMHD) turbulence and 2D thermal convection, which all exhibit direct energy cascades, a nonlocal behavior is found resulting in a logarithmic enhancement of the spectrum.

  6. ON THE BOTTLENECK CAPACITY EXPANSION PROBLEMS ON NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Yang Chao; Zhang Jianzhong

    2006-01-01

    This article considers a class of bottleneck capacity expansion problems. Such problems aim to enhance bottleneck capacity to a certain level with minimum cost. Given a network G(V, A,(-C)) consisting of a set of nodes V = {v1, v2,………, vn}, a set of arcs A(∪-){(vi, vj) | i = 1, 2,………, n; j = 1, 2,………, n} and a capacity vector (-C). The component (-C)ij of (-C) is the capacity of arc (vi, vj). Define the capacity of a subset A' of A as the minimum capacity of the arcs in A, the capacity of a family F of subsets of A is the maximum capacity of its members. There axe two types of expanding models. In the arc-expanding model, the unit cost to increase the capacity of arc (vi, vj) is wij. In the node-expanding model, it is assumed that the capacities of all arcs (vi, vi) which start at the same node vi should be increased by the same amount and that the unit cost to make such expansion is wi. This article considers three kinds of bottleneck capacity expansion problems (path,spanning arborescence and maximum flow) in both expanding models. For each kind of expansion problems, this article discusses the characteristics of the problems and presents several results on the complexity of the problems.

  7. A Macro Model for Traffic Flow with Consideration of Static Bottleneck

    Institute of Scientific and Technical Information of China (English)

    唐铁桥; 李鹏; 吴永洪; 黄海军

    2012-01-01

    In this paper, we develop a macro model for traffic flow with consideration of static bottleneck to explore the impacts of static bottleneck on traffic flow. The analytical and numerical results show that the proposed model can qualitatively describe the equilibrium flux, uniform flow and small perturbation under the action of a static bottleneck.

  8. Estimation of the bottleneck size in Florida panthers

    Science.gov (United States)

    Culver, M.; Hedrick, P.W.; Murphy, K.; O'Brien, S.; Hornocker, M.G.

    2008-01-01

    We have estimated the extent of genetic variation in museum (1890s) and contemporary (1980s) samples of Florida panthers Puma concolor coryi for both nuclear loci and mtDNA. The microsatellite heterozygosity in the contemporary sample was only 0.325 that in the museum samples although our sample size and number of loci are limited. Support for this estimate is provided by a sample of 84 microsatellite loci in contemporary Florida panthers and Idaho pumas Puma concolor hippolestes in which the contemporary Florida panther sample had only 0.442 the heterozygosity of Idaho pumas. The estimated diversities in mtDNA in the museum and contemporary samples were 0.600 and 0.000, respectively. Using a population genetics approach, we have estimated that to reduce either the microsatellite heterozygosity or the mtDNA diversity this much (in a period of c. 80years during the 20th century when the numbers were thought to be low) that a very small bottleneck size of c. 2 for several generations and a small effective population size in other generations is necessary. Using demographic data from Yellowstone pumas, we estimated the ratio of effective to census population size to be 0.315. Using this ratio, the census population size in the Florida panthers necessary to explain the loss of microsatellite variation was c .41 for the non-bottleneck generations and 6.2 for the two bottleneck generations. These low bottleneck population sizes and the concomitant reduced effectiveness of selection are probably responsible for the high frequency of several detrimental traits in Florida panthers, namely undescended testicles and poor sperm quality. The recent intensive monitoring both before and after the introduction of Texas pumas in 1995 will make the recovery and genetic restoration of Florida panthers a classic study of an endangered species. Our estimates of the bottleneck size responsible for the loss of genetic variation in the Florida panther completes an unknown aspect of this

  9. Congestion in a city with a central bottleneck

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Palma, André de

    2012-01-01

    We consider dynamic congestion in an urban setting where trip origins are spatially distributed. All travelers must pass through a downtown bottleneck in order to reach their destination in the CBD. Each traveler chooses departure time to maximize general concave scheduling utility. We find that......, at equilibrium, travelers sort according to their distance to the destination; the queue is always unimodal regardless of the spatial distribution of trip origins. We construct a welfare maximizing tolling regime, which eliminates congestion. All travelers located beyond a critical distance from the CBD gain...

  10. Congestion in a city with a central bottleneck

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Palma, André de

    2010-01-01

    We consider dynamic congestion in an urban setting where trip origins are spatially distributed. All travelers must pass through a downtown bottleneck in order to reach their destination in the CBD. Each traveler chooses departure time to maximize general concave scheduling utility. At equilibrium......, travelers sort according to their distance to the destination. We construct a welfare maximizing tolling regime, which eliminates congestion. All travelers located beyond a critical distance from the CBD gain from tolling, even when toll revenues are not redistributed, while nearby travelers lose. We...

  11. A cellular automaton model for a bridge traffic bottleneck

    Institute of Scientific and Technical Information of China (English)

    Shifa Xiao; Lingjiang Kong; Muren Liu

    2005-01-01

    A cellular automaton (CA) model is proposed in this paper to analyze a bridge traffic bottleneck. The simulation results with this model show that there are several phase transitions in the traffic average density, velocity and flow for each lane under a periodic boundary condition. An unstable phase in the traffic average density and velocity for the upstream and downstream lanes of the bridge is shown in a range of initial traffic densities. The critical points of the phase transitions and the phenomenon of the unstable phase found in the simulation are also explained with the mean-field theory.

  12. OPTIMISATION OF JOB SHOP SCHEDULING USING SHIFTING BOTTLENECK TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Katuru Phani Raja Kumar

    2013-07-01

    Full Text Available In manufacturing system the problem of scheduling machines is a difficult task to reach the due date of the productivity. The Job Shop Scheduling have been solved by different algorithms and methods based on the sequence operation constraints and processing times for small size problems. The JSSP with m machines and n jobs is represented to determine an optimal solution by using the shortest processing time technique and Gantt chart is drawn to visually represent the total makespan. The shifting bottleneck method has been used to reduce the total flow time of the JSSP and arrive at an optimal solution.

  13. The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

    Directory of Open Access Journals (Sweden)

    Ryan C Smith

    2014-08-01

    Full Text Available Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.

  14. Bottlenecks to vibrational energy flow in OCS: Structures and mechanisms

    CERN Document Server

    Paškauskas, R; Uzer, T

    2008-01-01

    Finding the causes for the nonstatistical vibrational energy relaxation in the planar carbonyl sulfide (OCS) molecule is a longstanding problem in chemical physics: Not only is the relaxation incomplete long past the predicted statistical relaxation time, but it also consists of a sequence of abrupt transitions between long-lived regions of localized energy modes. We report on the phase space bottlenecks responsible for this slow and uneven vibrational energy flow in this Hamiltonian system with three degrees of freedom. They belong to a particular class of two-dimensional invariant tori which are organized around elliptic periodic orbits. We relate the trapping and transition mechanisms with the linear stability of these structures.

  15. A bottleneck model of set-specific capture.

    Science.gov (United States)

    Moore, Katherine Sledge; Weissman, Daniel H

    2014-01-01

    Set-specific contingent attentional capture is a particularly strong form of capture that occurs when multiple attentional sets guide visual search (e.g., "search for green letters" and "search for orange letters"). In this type of capture, a potential target that matches one attentional set (e.g. a green stimulus) impairs the ability to identify a temporally proximal target that matches another attentional set (e.g. an orange stimulus). In the present study, we investigated whether set-specific capture stems from a bottleneck in working memory or from a depletion of limited resources that are distributed across multiple attentional sets. In each trial, participants searched a rapid serial visual presentation (RSVP) stream for up to three target letters (T1-T3) that could appear in any of three target colors (orange, green, or lavender). The most revealing findings came from trials in which T1 and T2 matched different attentional sets and were both identified. In these trials, T3 accuracy was lower when it did not match T1's set than when it did match, but only when participants failed to identify T2. These findings support a bottleneck model of set-specific capture in which a limited-capacity mechanism in working memory enhances only one attentional set at a time, rather than a resource model in which processing capacity is simultaneously distributed across multiple attentional sets.

  16. Divergent evolution peaks under intermediate population bottlenecks during bacterial experimental evolution

    OpenAIRE

    Vogwill, Tom; Phillips, Robyn L.; Gifford, Danna R.; MacLean, R. Craig

    2016-01-01

    There is growing evidence that parallel molecular evolution is common, but its causes remain poorly understood. Demographic parameters such as population bottlenecks are predicted to be major determinants of parallelism. Here, we test the hypothesis that bottleneck intensity shapes parallel evolution by elucidating the genomic basis of adaptation to antibiotic-supplemented media in hundreds of populations of the bacterium Pseudomonas fluorescens Pf0-1. As expected, bottlenecking decreased the...

  17. Queuing model of a traffic bottleneck with bimodal arrival rate

    Science.gov (United States)

    Woelki, Marko

    2016-06-01

    This paper revisits the problem of tuning the density in a traffic bottleneck by reduction of the arrival rate when the queue length exceeds a certain threshold, studied recently for variants of totally asymmetric simple exclusion process (TASEP) and Burgers equation. In the present approach, a simple finite queuing system is considered and its contrasting “phase diagram” is derived. One can observe one jammed region, one low-density region and one region where the queue length is equilibrated around the threshold. Despite the simplicity of the model the physics is in accordance with the previous approach: The density is tuned at the threshold if the exit rate lies in between the two arrival rates.

  18. Traffic Flow States in a Freeway with Bottleneck

    Institute of Scientific and Technical Information of China (English)

    PENG Zi-Hui; SUN Gang; ZHU Jing-Yi

    2009-01-01

    The system of mixture of single lane and double lane is studied by a cellular automata model, which is developed by us based on the Nagel and Schreckenberg's models. We justify that the model can reach a stable states quickly. The density distributions of the stable state is presented for several cases, which illustrate the manner of the congestion. The relationship between the outflow rate and the total number of vehicles and that between the outflow rate and the density just before the bottleneck are both given. Comparing with the relationship that occurring in the granular flow, we conclude that the transition from the free traffic flow to the congested traffic flow can also be attributed to the abrupt variation through unstable flow state, which can naturally explain the discontinuities and the complex time variation behavior observed in the traffic flow experiments.

  19. Situation awareness of active distribution network: roadmap, technologies, and bottlenecks

    DEFF Research Database (Denmark)

    Lin, Jin; Wan, Can; Song, Yonghua

    2016-01-01

    With the rapid development of local generation and demand response, the active distribution network (ADN), which aggregates and manages miscellaneous distributed resources, has moved from theory to practice. Secure and optimal operations now require an advanced situation awareness (SA) system so...... in the project of developing an SA system as the basic component of a practical active distribution management system (ADMS) deployed in Beijing, China, is presented. This paper reviews the ADN’s development roadmap by illustrating the changes that are made in elements, topology, structure, and control scheme....... Taking into consideration these hardware changes, a systematic framework is proposed for the main components and the functional hierarchy of an SA system for the ADN. The SA system’s implementation bottlenecks are also presented, including, but not limited to issues in big data platform, distribution...

  20. Genetic diversity and bottleneck studies in the Marwari horse breed

    Indian Academy of Sciences (India)

    A. K. Gupta; M. Chauhan; S. N. Tandon; Sonia

    2005-12-01

    Genetic diversity within the Marwari breed of horses was evaluated using 26 different microsatellite pairs with 48 DNA samples from unrelated horses. This molecular characterisation was undertaken to evaluate the problem of genetic bottlenecks also, if any, in this breed. The estimated mean (± s.e.) allelic diversity was 5.9 (± 2.24), with a total of 133 alleles. A high level of genetic variability within this breed was observed in terms of high values of mean (± s.e.) effective number of alleles (3.3 ± 1.27), observed heterozygosity (0.5306 ± 0.22), expected Levene’s heterozygosity (0.6612 ± 0.15), expected Nei’s heterozygosity (0.6535 ± 0.14), and polymorphism information content (0.6120 ± 0.03). Low values of Wright’s fixation index, $F_{\\text{IS}}$ (0.2433 ± 0.05) indicated low levels of inbreeding. This basic study indicated the existence of substantial genetic diversity in the Marwari horse population. No significant genotypic linkage disequilibrium was detected across the population, suggesting no evidence of linkage between loci. A normal ‘L’ shaped distribution of mode–shift test, non-significant heterozygote excess on the basis of different models, as revealed from Sign, Standardized differences and Wilcoxon sign rank tests as well as non-significant ratio value suggested that there was no recent bottleneck in the existing Marwari breed population, which is important information for equine breeders. This study also revealed that the Marwari breed can be differentiated from some other exotic breeds of horses on the basis of three microsatellite primers.

  1. Divergent evolution peaks under intermediate population bottlenecks during bacterial experimental evolution

    Science.gov (United States)

    Phillips, Robyn L.; Gifford, Danna R.; MacLean, R. Craig

    2016-01-01

    There is growing evidence that parallel molecular evolution is common, but its causes remain poorly understood. Demographic parameters such as population bottlenecks are predicted to be major determinants of parallelism. Here, we test the hypothesis that bottleneck intensity shapes parallel evolution by elucidating the genomic basis of adaptation to antibiotic-supplemented media in hundreds of populations of the bacterium Pseudomonas fluorescens Pf0-1. As expected, bottlenecking decreased the rate of phenotypic and molecular adaptation. Surprisingly, bottlenecking had no impact on the likelihood of parallel adaptive molecular evolution at a genome-wide scale. However, bottlenecking had a profound impact on the genes involved in antibiotic resistance. Specifically, under either intense or weak bottlenecking, resistance predominantly evolved by strongly beneficial mutations which provide high levels of antibiotic resistance. In contrast with intermediate bottlenecking regimes, resistance evolved by a greater diversity of genetic mechanisms, significantly reducing the observed levels of parallel genetic evolution. Our results demonstrate that population bottlenecking can be a major predictor of parallel evolution, but precisely how may be more complex than many simple theoretical predictions. PMID:27466449

  2. Bottleneck Analysis of the Minimum Coat Problem for the Generalized Network Based on Augmented Forest Structure

    Institute of Scientific and Technical Information of China (English)

    江永亨; 王军; 等

    2003-01-01

    The bottleneck analysis of the minimum coat problem for the generalized netwok(MCPGN) is discussed.The analysis is based on the network simplex algorithm,which gains negative cost graphs by constructing augmented forest structure,then augments flows on the negative cost graphs until the optimal revolution is gained Bottleneck structure is presented after analyzing the augmented forest structure.The negative cost augmented graphs are constructed with the bottleneck structure.The arcs that block the negative cost augmented graph are the elements of the bottleneck.The bottleneck analysis for the generalized circulation problem,the minimum circulation problem and the circulation problem are discussed respectively as the basal problems,then that for MCPGN is achieved.An example is presented at the end.

  3. Bottlenecks of motion processing during a visual glance: the leaky flask model.

    Directory of Open Access Journals (Sweden)

    Haluk Öğmen

    Full Text Available Where do the bottlenecks for information and attention lie when our visual system processes incoming stimuli? The human visual system encodes the incoming stimulus and transfers its contents into three major memory systems with increasing time scales, viz., sensory (or iconic memory, visual short-term memory (VSTM, and long-term memory (LTM. It is commonly believed that the major bottleneck of information processing resides in VSTM. In contrast to this view, we show major bottlenecks for motion processing prior to VSTM. In the first experiment, we examined bottlenecks at the stimulus encoding stage through a partial-report technique by delivering the cue immediately at the end of the stimulus presentation. In the second experiment, we varied the cue delay to investigate sensory memory and VSTM. Performance decayed exponentially as a function of cue delay and we used the time-constant of the exponential-decay to demarcate sensory memory from VSTM. We then decomposed performance in terms of quality and quantity measures to analyze bottlenecks along these dimensions. In terms of the quality of information, two thirds to three quarters of the motion-processing bottleneck occurs in stimulus encoding rather than memory stages. In terms of the quantity of information, the motion-processing bottleneck is distributed, with the stimulus-encoding stage accounting for one third of the bottleneck. The bottleneck for the stimulus-encoding stage is dominated by the selection compared to the filtering function of attention. We also found that the filtering function of attention is operating mainly at the sensory memory stage in a specific manner, i.e., influencing only quantity and sparing quality. These results provide a novel and more complete understanding of information processing and storage bottlenecks for motion processing.

  4. Eye shape and the nocturnal bottleneck of mammals.

    Science.gov (United States)

    Hall, Margaret I; Kamilar, Jason M; Kirk, E Christopher

    2012-12-22

    Most vertebrate groups exhibit eye shapes that vary predictably with activity pattern. Nocturnal vertebrates typically have large corneas relative to eye size as an adaptation for increased visual sensitivity. Conversely, diurnal vertebrates generally demonstrate smaller corneas relative to eye size as an adaptation for increased visual acuity. By contrast, several studies have concluded that many mammals exhibit typical nocturnal eye shapes, regardless of activity pattern. However, a recent study has argued that new statistical methods allow eye shape to accurately predict activity patterns of mammals, including cathemeral species (animals that are equally likely to be awake and active at any time of day or night). Here, we conduct a detailed analysis of eye shape and activity pattern in mammals, using a broad comparative sample of 266 species. We find that the eye shapes of cathemeral mammals completely overlap with nocturnal and diurnal species. Additionally, most diurnal and cathemeral mammals have eye shapes that are most similar to those of nocturnal birds and lizards. The only mammalian clade that diverges from this pattern is anthropoids, which have convergently evolved eye shapes similar to those of diurnal birds and lizards. Our results provide additional evidence for a nocturnal 'bottleneck' in the early evolution of crown mammals.

  5. Photonic ADC: overcoming the bottleneck of electronic jitter.

    Science.gov (United States)

    Khilo, Anatol; Spector, Steven J; Grein, Matthew E; Nejadmalayeri, Amir H; Holzwarth, Charles W; Sander, Michelle Y; Dahlem, Marcus S; Peng, Michael Y; Geis, Michael W; DiLello, Nicole A; Yoon, Jung U; Motamedi, Ali; Orcutt, Jason S; Wang, Jade P; Sorace-Agaskar, Cheryl M; Popović, Miloš A; Sun, Jie; Zhou, Gui-Rong; Byun, Hyunil; Chen, Jian; Hoyt, Judy L; Smith, Henry I; Ram, Rajeev J; Perrott, Michael; Lyszczarz, Theodore M; Ippen, Erich P; Kärtner, Franz X

    2012-02-13

    Accurate conversion of wideband multi-GHz analog signals into the digital domain has long been a target of analog-to-digital converter (ADC) developers, driven by applications in radar systems, software radio, medical imaging, and communication systems. Aperture jitter has been a major bottleneck on the way towards higher speeds and better accuracy. Photonic ADCs, which perform sampling using ultra-stable optical pulse trains generated by mode-locked lasers, have been investigated for many years as a promising approach to overcome the jitter problem and bring ADC performance to new levels. This work demonstrates that the photonic approach can deliver on its promise by digitizing a 41 GHz signal with 7.0 effective bits using a photonic ADC built from discrete components. This accuracy corresponds to a timing jitter of 15 fs - a 4-5 times improvement over the performance of the best electronic ADCs which exist today. On the way towards an integrated photonic ADC, a silicon photonic chip with core photonic components was fabricated and used to digitize a 10 GHz signal with 3.5 effective bits. In these experiments, two wavelength channels were implemented, providing the overall sampling rate of 2.1 GSa/s. To show that photonic ADCs with larger channel counts are possible, a dual 20-channel silicon filter bank has been demonstrated.

  6. HIV/AIDS: global trends, global funds and delivery bottlenecks

    Directory of Open Access Journals (Sweden)

    Hadingham Jacqui

    2005-08-01

    Full Text Available Abstract Globalisation affects all facets of human life, including health and well being. The HIV/AIDS epidemic has highlighted the global nature of human health and welfare and globalisation has given rise to a trend toward finding common solutions to global health challenges. Numerous international funds have been set up in recent times to address global health challenges such as HIV. However, despite increasingly large amounts of funding for health initiatives being made available to poorer regions of the world, HIV infection rates and prevalence continue to increase world wide. As a result, the AIDS epidemic is expanding and intensifying globally. Worst affected are undoubtedly the poorer regions of the world as combinations of poverty, disease, famine, political and economic instability and weak health infrastructure exacerbate the severe and far-reaching impacts of the epidemic. One of the major reasons for the apparent ineffectiveness of global interventions is historical weaknesses in the health systems of underdeveloped countries, which contribute to bottlenecks in the distribution and utilisation of funds. Strengthening these health systems, although a vital component in addressing the global epidemic, must however be accompanied by mitigation of other determinants as well. These are intrinsically complex and include social and environmental factors, sexual behaviour, issues of human rights and biological factors, all of which contribute to HIV transmission, progression and mortality. An equally important factor is ensuring an equitable balance between prevention and treatment programmes in order to holistically address the challenges presented by the epidemic.

  7. Clogging transition of many-particle systems flowing through bottlenecks.

    Science.gov (United States)

    Zuriguel, Iker; Parisi, Daniel Ricardo; Hidalgo, Raúl Cruz; Lozano, Celia; Janda, Alvaro; Gago, Paula Alejandra; Peralta, Juan Pablo; Ferrer, Luis Miguel; Pugnaloni, Luis Ariel; Clément, Eric; Maza, Diego; Pagonabarraga, Ignacio; Garcimartín, Angel

    2014-12-04

    When a large set of discrete bodies passes through a bottleneck, the flow may become intermittent due to the development of clogs that obstruct the constriction. Clogging is observed, for instance, in colloidal suspensions, granular materials and crowd swarming, where consequences may be dramatic. Despite its ubiquity, a general framework embracing research in such a wide variety of scenarios is still lacking. We show that in systems of very different nature and scale -including sheep herds, pedestrian crowds, assemblies of grains, and colloids- the probability distribution of time lapses between the passages of consecutive bodies exhibits a power-law tail with an exponent that depends on the system condition. Consequently, we identify the transition to clogging in terms of the divergence of the average time lapse. Such a unified description allows us to put forward a qualitative clogging state diagram whose most conspicuous feature is the presence of a length scale qualitatively related to the presence of a finite size orifice. This approach helps to understand paradoxical phenomena, such as the faster-is-slower effect predicted for pedestrians evacuating a room and might become a starting point for researchers working in a wide variety of situations where clogging represents a hindrance.

  8. Analysis of registered CDM projects: potential removal of evidenced bottlenecks

    Energy Technology Data Exchange (ETDEWEB)

    Agosto, D.; Bombard, P.; Gostinelli, F.

    2007-07-01

    The Clean Development Mechanism (CDM) has developed during its first period of implementation, a distinctive set of patterns. The authors thought of concentrating on the CDM analysis in order to highlight potential remedies or reasons for given bottlenecks. In order to establish a sort of extensive SWOT analysis for CDMs, all the 356 projects actually (November 2006) registered at UNFCCC were examined, together with all the about 1000 PDDs presented to the UNFCCC but not registered yet. The CDM projects have been studied trying to cluster projects according to relevant characteristics, both from a technical and an economic point of view. Chosen indicators are meant to identify: more convenient/more diffused energy system for a CDM; reasons for a geographical distribution of different types of projects; potentials for a future exploitation of lower used technologies in CDM. Conclusions are drawn and appropriate tables and graphs presented. (1) the Baseline Emission Factor, combined to economic patterns, is the pivotal factor that characterizes both choices of host country and technology; (2) some technologies can exploit appropriately CDM scheme, whilst other technologies, are constrained by it. (3) there are still some important weak points: grouping of non Annex I countries; crediting period; criteria for the evaluation of sustainable development. (auth)

  9. The effect of population bottlenecks on mutation rate evolution in asexual populations.

    Science.gov (United States)

    Raynes, Y; Halstead, A L; Sniegowski, P D

    2014-01-01

    In the absence of recombination, a mutator allele can spread through a population by hitchhiking with beneficial mutations that appear in its genetic background. Theoretical studies over the past decade have shown that the survival and fixation probability of beneficial mutations can be severely reduced by population size bottlenecks. Here, we use computational modelling and evolution experiments with the yeast S. cerevisiae to examine whether population bottlenecks can affect mutator dynamics in adapting asexual populations. In simulation, we show that population bottlenecks can inhibit mutator hitchhiking with beneficial mutations and are most effective at lower beneficial mutation supply rates. We then subjected experimental populations of yeast propagated at the same effective population size to three different bottleneck regimes and observed that the speed of mutator hitchhiking was significantly slower at smaller bottlenecks, consistent with our theoretical expectations. Our results, thus, suggest that bottlenecks can be an important factor in mutation rate evolution and can in certain circumstances act to stabilize or, at least, delay the progressive elevation of mutation rates in asexual populations. Additionally, our findings provide the first experimental support for the theoretically postulated effect of population bottlenecks on beneficial mutations and demonstrate the usefulness of studying mutator frequency dynamics for understanding the underlying dynamics of fitness-affecting mutations.

  10. Integrated Variable Speed Limits Control and Ramp Metering for Bottleneck Regions on Freeway

    Directory of Open Access Journals (Sweden)

    Ming-hui Ma

    2015-01-01

    Full Text Available To enhance the efficiency of the existing freeway system and therefore to mitigate traffic congestion and related problems on the freeway mainline lane-drop bottleneck region, the advanced strategy for bottleneck control is essential. This paper proposes a method that integrates variable speed limits and ramp metering for freeway bottleneck region control to relieve the chaos in bottleneck region. To this end, based on the analyses of spatial-temporal patterns of traffic flow, a macroscopic traffic flow model is extended to describe the traffic flow operating characteristic by considering the impacts of variable speed limits in mainstream bottleneck region. In addition, to achieve the goal of balancing the priority of the vehicles on mainline and on-ramp, increasing capacity, and reducing travel delay on bottleneck region, an improved control model, as well as an advanced control strategy that integrates variable speed limits and ramp metering, is developed. The proposed method is tested in simulation for a real freeway infrastructure feed and calibrates real traffic variables. The results demonstrate that the proposed method can substantially improve the traffic flow efficiency of mainline and on-ramp and enhance the quality of traffic flow at the investigated freeway mainline bottleneck.

  11. Damage to white matter bottlenecks contributes to language impairments after left hemispheric stroke.

    Science.gov (United States)

    Griffis, Joseph C; Nenert, Rodolphe; Allendorfer, Jane B; Szaflarski, Jerzy P

    2017-01-01

    Damage to the white matter underlying the left posterior temporal lobe leads to deficits in multiple language functions. The posterior temporal white matter may correspond to a bottleneck where both dorsal and ventral language pathways are vulnerable to simultaneous damage. Damage to a second putative white matter bottleneck in the left deep prefrontal white matter involving projections associated with ventral language pathways and thalamo-cortical projections has recently been proposed as a source of semantic deficits after stroke. Here, we first used white matter atlases to identify the previously described white matter bottlenecks in the posterior temporal and deep prefrontal white matter. We then assessed the effects of damage to each region on measures of verbal fluency, picture naming, and auditory semantic decision-making in 43 chronic left hemispheric stroke patients. Damage to the posterior temporal bottleneck predicted deficits on all tasks, while damage to the anterior bottleneck only significantly predicted deficits in verbal fluency. Importantly, the effects of damage to the bottleneck regions were not attributable to lesion volume, lesion loads on the tracts traversing the bottlenecks, or damage to nearby cortical language areas. Multivariate lesion-symptom mapping revealed additional lesion predictors of deficits. Post-hoc fiber tracking of the peak white matter lesion predictors using a publicly available tractography atlas revealed evidence consistent with the results of the bottleneck analyses. Together, our results provide support for the proposal that spatially specific white matter damage affecting bottleneck regions, particularly in the posterior temporal lobe, contributes to chronic language deficits after left hemispheric stroke. This may reflect the simultaneous disruption of signaling in dorsal and ventral language processing streams.

  12. Microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks.

    Science.gov (United States)

    Kerner, Boris S; Klenov, Sergey L

    2003-09-01

    A microscopic theory of spatial-temporal congested traffic patterns at highway bottlenecks due to on-ramps, merge bottlenecks (a reduction of highway lanes), and off-ramps is presented. The basic postulate of three-phase traffic theory is used, which claims that homogeneous (in space and time) model solutions (steady states) of synchronized flow cover a two dimensional region in the flow-density plane [B. S. Kerner, Phys. Rev. Lett. 81, 3797 (1998); Trans. Res. Rec. 1678, 160 (1999)]. Phase transitions leading to diverse congested patterns, pattern evolution, and pattern nonlinear features have been found. Diagrams of congested patterns, i.e., regions of the pattern emergence dependent on traffic demand, have been derived. Diverse effects of metastability with respect to the pattern formation have been found. The microscopic theory allows us to explain the main empirical pattern features at on-ramps and off-ramps which have recently been found [B. S. Kerner, Phys. Rev. E 65, 046138 (2002)]. (i) Rather than moving jams, synchronized flow first occurs at bottlenecks if the flow rate is slowly increasing. Wide moving jams can spontaneously occur only in synchronized flow. (ii) General patterns (GP) and synchronized flow patterns (SP) can spontaneously emerge at the bottlenecks. There can be the widening SP (WSP), the moving SP (MSP), and the localized SP. (iii) At on-ramps cases of "weak" and "strong" congestion should be distinguished. In contrast to weak congestion, under strong congestion the flow rate in synchronized flow in GP reaches a limit flow rate, the frequency of the moving jam emergence reaches a maximum, i.e., the GP characteristics under strong congestion do not depend on traffic demand. (iv) At the off-ramp GP with weak congestion occur. (v) A study of the pattern formation on a highway with two bottlenecks shows that diverse expanded patterns can occur, which cover both bottlenecks. SP first emerged at the downstream bottleneck can be caught at the

  13. Development of control strategy of variable speed limits for improving traffic operations at freeway bottlenecks

    Institute of Scientific and Technical Information of China (English)

    李志斌; 刘攀; 王炜; 徐铖铖

    2014-01-01

    A control strategy of variable speed limits (VSL) was developed to reduce the travel time at freeway recurrent bottleneck areas. The proposed control strategy particularly focused on preventing the capacity drop and increasing the discharge flow. A cell transmission model (CTM) was developed to evaluate the effects of the proposed VSL control strategy on the traffic operations. The results show that the total travel time is reduced by 25.5% and the delay is reduced by 56.1%. The average travel speed is increased by 34.3% and the queue length is reduced by 31.0%. The traffic operation is improved by the proposed VSL control strategy. The way to use the proposed VSL control strategy in different types of freeway bottlenecks was also discussed by considering different traffic flow characteristics. It is concluded that the VSL control strategy is effective for merge bottlenecks but is less effective for diverge bottlenecks.

  14. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    their proportions in the downriver stretch: fish samples in the ladder were clearly dominated by a few species, including some that do not need to be translocated. Thus, selectivity constitutes an important bottleneck to initiatives for translocating fish aimed at conserving their stocks or biodiversity. It is urgent to review the decision-making process for the construction of fish passages and to evaluate the functioning of those already operating.

  15. On the Accurate Identification of Network Paths Having a Common Bottleneck

    Directory of Open Access Journals (Sweden)

    Muhammad Murtaza Yousaf

    2013-01-01

    Full Text Available We present a new mechanism for detecting shared bottlenecks between end-to-end paths in a network. Our mechanism, which only needs one-way delays from endpoints as an input, is based on the well-known linear algebraic approach: singular value decomposition (SVD. Clusters of flows which share a bottleneck are extracted from SVD results by applying an outlier detection method. Simulations with varying topologies and different network conditions show the high accuracy of our technique.

  16. Central as well as peripheral attentional bottlenecks in dual-task performance activate lateral prefrontal cortices

    Directory of Open Access Journals (Sweden)

    Andre J Szameitat

    2016-03-01

    Full Text Available Human information processing suffers from severe limitations in parallel processing. In particular, when required to respond to two stimuli in rapid succession, processing bottlenecks may appear at central and peripheral stages of task processing. Importantly, it has been suggested that executive functions are needed to resolve the interference arising at such bottlenecks. The aims of the present study were to test whether central attentional limitations (i.e., bottleneck at the decisional response selection stage as well as peripheral limitations (i.e., bottleneck at response initiation both demand executive functions located in the lateral prefrontal cortex. For this, we re-analysed two previous studies, in which a total of 33 participants performed a dual-task according to the paradigm of the psychological refractory period (PRP during fMRI. In one study (N=17, the PRP task consisted of two two-choice response tasks known to suffer from a central bottleneck (CB group. In the other study (N=16, the PRP task consisted of two simple-response tasks known to suffer from a peripheral bottleneck (PB group. Both groups showed considerable dual-task costs in form of slowing of the second response in the dual-task (PRP effect. Imaging results are based on the subtraction of both single-tasks from the dual-task within each group. In the CB group, the bilateral middle frontal gyri and inferior frontal gyri were activated. Higher activation in these areas was associated with lower dual-task costs. In the PB group, the right middle frontal and inferior frontal gyrus were activated. Here, higher activation was associated with higher dual-task costs. In conclusion we suggest that central and peripheral bottlenecks both demand executive functions located in lateral prefrontal cortices. Differences between the CB and PB groups with respect to the exact prefrontal areas activated and the correlational patterns suggest that the executive functions resolving

  17. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    2007-01-01

    their proportions in the downriver stretch: fish samples in the ladder were clearly dominated by a few species, including some that do not need to be translocated. Thus, selectivity constitutes an important bottleneck to initiatives for translocating fish aimed at conserving their stocks or biodiversity. It is urgent to review the decision-making process for the construction of fish passages and to evaluate the functioning of those already operating.Dezenas de escadas de peixes foram construídas em barragens de reservatórios brasileiros, mas são raros os estudos acerca de suas eficiências como instrumentos de conservação da ictiofauna Neotropical, em especial de espécies migradoras. Neste contexto, o presente estudo teve como objetivo avaliar a seletividade específica no ingresso e ascensão de peixes na escada localizada junto à barragem de Lajeado (UHE Luis Eduardo Magalhães, rio Tocantins. Amostragens foram realizadas mensalmente de novembro de 2002 a outubro de 2003 nos tanques de descanso da escada, utilizando tarrafas, e no trecho a jusante, utilizando redes de espera. A avaliação da seletividade no ingresso da escada foi realizada através da comparação da ocorrência, abundância relativa, dominância e congruência dos ranks de abundância de espécies migradoras e não migradoras na escada e no trecho imediatamente a jusante. A riqueza e abundância específica nos diferentes tanques de descanso foram utilizadas para avaliar a seletividade ao longo da escada. Os efeitos das variações temporais do nível hidrométrico de jusante e da velocidade de fluxo na seletividade foram também analisados. Das 130 espécies registradas a jusante, 63,2% foram capturadas na escada, com claro favorecimento das espécies migradoras. Entretanto, mais de 2/3 das capturas pertenceram a apenas três espécies (Rhaphiodon vulpinus, Psectrogaster amazonica e Oxydoras niger. Embora a maioria das espécies que ingressa na escada possa alcançar seu topo, constatou

  18. Brown world forests: increased ungulate browsing keeps temperate trees in recruitment bottlenecks in resource hotspots.

    Science.gov (United States)

    Churski, Marcin; Bubnicki, Jakub W; Jędrzejewska, Bogumiła; Kuijper, Dries P J; Cromsigt, Joris P G M

    2017-04-01

    Plant biomass consumers (mammalian herbivory and fire) are increasingly seen as major drivers of ecosystem structure and function but the prevailing paradigm in temperate forest ecology is still that their dynamics are mainly bottom-up resource-controlled. Using conceptual advances from savanna ecology, particularly the demographic bottleneck model, we present a novel view on temperate forest dynamics that integrates consumer and resource control. We used a fully factorial experiment, with varying levels of ungulate herbivory and resource (light) availability, to investigate how these factors shape recruitment of five temperate tree species. We ran simulations to project how inter- and intraspecific differences in height increment under the different experimental scenarios influence long-term recruitment of tree species. Strong herbivore-driven demographic bottlenecks occurred in our temperate forest system, and bottlenecks were as strong under resource-rich as under resource-poor conditions. Increased browsing by herbivores in resource-rich patches strongly counteracted the increased escape strength of saplings in these patches. This finding is a crucial extension of the demographic bottleneck model which assumes that increased resource availability allows plants to more easily escape consumer-driven bottlenecks. Our study demonstrates that a more dynamic understanding of consumer-resource interactions is necessary, where consumers and plants both respond to resource availability.

  19. Bottlenecks and Hubs in Inferred Networks Are Important for Virulence in Salmonella typhimurium

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, Jason E.; Taylor, Ronald C.; Yoon, Hyunjin; Heffron, Fred

    2009-02-01

    Recent advances in experimental methods have provided sufficient data to consider systems as large networks of interconnected components. High-throughput determination of protein-protein interaction networks has led to the observation that topological bottlenecks, that is proteins defined by high centrality in the network, are enriched in proteins with systems-level phenotypes such as essentiality. Global transcriptional profiling by microarray analysis has been used extensively to characterize systems, for example, cellular response to environmental conditions and genetic mutations. These transcriptomic datasets have been used to infer regulatory and functional relationship networks based on co-regulation. We use the context likelihood of relatedness (CLR) method to infer networks from two datasets gathered from the pathogen Salmonella typhimurium; one under a range of environmental culture conditions and the other from deletions of 15 regulators found to be essential in virulence. Bottleneck nodes were identified from these inferred networks and we show that these nodes are significantly more likely to be essential for virulence than their non-bottleneck counterparts. A network generated using Pearson correlation did not display this behavior. Overall this study demonstrates that topology of networks inferred from global transcriptional profiles provides information about the systems-level roles of bottleneck genes. Analysis of the differences between the two CLR-derived networks suggests that the bottleneck nodes are either mediators of transitions between system states or sentinels that reflect the dynamics of these transitions.

  20. Bottlenecks and hubs in inferred networks are important for virulence in Salmonella typhimurium.

    Science.gov (United States)

    McDermott, Jason E; Taylor, Ronald C; Yoon, Hyunjin; Heffron, Fred

    2009-02-01

    Recent advances in experimental methods have provided sufficient data to consider systems as large networks of interconnected components. High-throughput determination of protein-protein interaction networks has led to the observation that topological bottlenecks, proteins defined by high centrality in the network, are enriched in proteins with systems-level phenotypes such as essentiality. Global transcriptional profiling by microarray analysis has been used extensively to characterize systems, for example, examining cellular response to environmental conditions and effects of genetic mutations. These transcriptomic datasets have been used to infer regulatory and functional relationship networks based on co-regulation. We use the context likelihood of relatedness (CLR) method to infer networks from two datasets gathered from the pathogen Salmonella typhimurium: one under a range of environmental culture conditions and the other from deletions of 15 regulators found to be essential in virulence. Bottleneck and hub genes were identified from these inferred networks, and we show for the first time that these genes are significantly more likely to be essential for virulence than their non-bottleneck or non-hub counterparts. Networks generated using simple similarity metrics (correlation and mutual information) did not display this behavior. Overall, this study demonstrates that topology of networks inferred from global transcriptional profiles provides information about the systems-level roles of bottleneck genes. Analysis of the differences between the two CLR-derived networks suggests that the bottleneck nodes are either mediators of transitions between system states or sentinels that reflect the dynamics of these transitions.

  1. Dynamic bottleneck elimination in mattress manufacturing line using theory of constraints.

    Science.gov (United States)

    Gundogar, Emin; Sari, Murat; Kokcam, Abdullah H

    2016-01-01

    There is a tough competition in the furniture sector like other sectors. Along with the varying product range, production system should also be renewed on a regular basis and the production costs should be kept under control. In this study, spring mattress manufacturing line of a furniture manufacturing company is analyzed. The company wants to increase its production output with new investments. The objective is to find the bottlenecks in production line in order to balance the semi-finished material flow. These bottlenecks are investigated and several different scenarios are tested to improve the current manufacturing system. The problem with a main theme based on the elimination of the bottleneck is solved using Goldratt and Cox's theory of constraints with a simulation based heuristic method. Near optimal alternatives are determined by system models built in Arena 13.5 simulation software. Results show that approximately 46 % capacity enhancements with 2 buffer stocks have increased average production by 88.8 %.

  2. Effects of speed bottleneck on traffic flow with feedback control signal

    Science.gov (United States)

    Zhu, Kangli; Bi, Jiantao; Wu, Jianjun; Li, Shubin

    2016-09-01

    Various car-following models (CMs) have been developed to capture the complex characteristics of microscopic traffic flow, among which the coupled map CM can better reveal and reflect various phenomena of practical traffic flow. Capacity change at bottleneck contributes to high-density traffic flow upstream the bottleneck and contains very complex dynamic behavior. In this paper, we analyze the effect of speed bottleneck on the spatial-temporal evolution characteristics of traffic flow, and propose a method to reduce traffic congestion with the feedback control signal based on CM. Simulation results highlight the potential of using the feedback signal to control the stop-and-go wave and furthermore to alleviate the traffic congestion effectively.

  3. The Effect of an Extreme and Prolonged Population Bottleneck on Patterns of Deleterious Variation

    DEFF Research Database (Denmark)

    Pedersen, Casper-Emil T; Lohmueller, Kirk E; Grarup, Niels;

    2016-01-01

    to a markedly more extreme distribution of allele frequencies than seen for any other human population, making the Inuit the perfect population for investigating the effect of a bottleneck on patterns of deleterious variation. When comparing proxies for genetic load that assume an additive effect of deleterious......The genetic consequences of population bottlenecks on patterns of deleterious genetic variation in human populations are of tremendous interest. Based on exome sequencing of 18 Greenlandic Inuit here we show that the Inuit have undergone a severe ~20,000 year long bottleneck. This has led...... alleles, the Inuit show, at most, a slight increase in load compared to European, East Asian, and African populations. Specifically, we observe

  4. A recent bottleneck of Y chromosome diversity coincides with a global change in culture

    KAUST Repository

    Karmin, Monika

    2015-04-30

    It is commonly thought that human genetic diversity in non-African populations was shaped primarily by an out-of-Africa dispersal 50–100 thousand yr ago (kya). Here, we present a study of 456 geographically diverse high-coverage Y chromosome sequences, including 299 newly reported samples. Applying ancient DNA calibration, we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192–307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47–52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males.

  5. "BOTTLENECK" AND COUNTERMEASURE OF HIGH-TECHNOLOGIZATION OF MARINE INDUSTRY IN CHINA

    Institute of Scientific and Technical Information of China (English)

    LUAN Wei-xin

    2004-01-01

    This article deeply researched into the existent five problems and four main "bottlenecks" in the high-technologization of marine industry in China on the basis of analyzing the new trends in international marine problems and the necessity of implementing the strategy of developing China based on marine. This article brought up specific measures to the five "bottlenecks" according to the situations, and pointed out that new marine industry should be high-technologization and the traditional marine industry should be reformed by high-technique. The research results may provide the scientific basis for realizing the high-technologization of marine industry in China.

  6. Reducing the Analytical Bottleneck for Domain Scientists: Lessons from a Climate Data Visualization Case Study

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Aritra; Poco, Jorge; Bertini, Enrico; Silva, Claudio T.

    2016-01-31

    The gap between large-scale data production rate and the rate of generation of data-driven scientific insights has led to an analytical bottleneck in scientific domains like climate, biology, etc. This is primarily due to the lack of innovative analytical tools that can help scientists efficiently analyze and explore alternative hypotheses about the data, and communicate their findings effectively to a broad audience. In this paper, by reflecting on a set of successful collaborative research efforts between with a group of climate scientists and visualization researchers, we introspect how interactive visualization can help reduce the analytical bottleneck for domain scientists.

  7. Research on polymorphism of production logistics bottleneck based on bottleneck index%基于瓶颈指数的生产物流瓶颈多态性研究

    Institute of Scientific and Technical Information of China (English)

    唐娟; 刘志

    2011-01-01

    Aiming at the shifting phenomenon of production logistics in the manufacturing shop under uncertain environments, the conceptual model which is composed of main bottleneck, second bottleneck, sensitive bottleneck and insensitive bottleneck is built;taken production capability,production load,quality assurance capability and production cost of manufacturing unit into con-sideration ,mathematical model of bottleneck index is established to measure bottleneck degree accurately;based on bottleneck in-dex, the prediction mechanism is established to identify bottleneck and non-bottleneck,main bottleneck and second bottleneck, then sensitive coefficient of bottleneck shifting is founded to accurately judge sensitive bottleneck and insensitive bottleneck of the manufacturing shop,which provide a method support for forecasting and monitoring the phenomenon of bottleneck shifting.%针对不确定性环境下制造车间生产物流瓶颈漂移现象,建立以主瓶颈、次瓶颈、灵敏型瓶颈和迟钝型瓶颈为主的瓶颈多态性概念模型;综合考虑制造单元的生产能力、生产负荷、质量保证能力和生产成本,构建瓶颈指数数学模型,以实现制造单元瓶颈度的准确度量;以瓶颈指数为基础,构建瓶颈及主次瓶颈的预测机制,并构建瓶颈漂移敏感系数,以实现制造车间生产物流瓶颈与非瓶颈、主瓶颈和次瓶颈、灵敏型瓶颈和迟钝型瓶颈的准确判别,进而为实现瓶颈漂移现象的预测和监控提供一种方法.

  8. South West Georgia: an important bottleneck for raptor migration during autumn

    NARCIS (Netherlands)

    Verhelst, B.; Jansen, J.; Vansteelant, W.

    2011-01-01

    Counts of migrating raptors at Batumi, Georgia, revealed the eastern Black Sea coast to form one of the most important bottlenecks for raptor migration during autumn in the Eurasian-African migration system. Totals for 10 species (European Honey-buzzard Pernis apivorus, Steppe Buzzard Buteo buteo vu

  9. Lake restoration studies: failures, bottlenecks and prospects of new ecotechnological measures

    NARCIS (Netherlands)

    Gulati, R.D.; Dionisio Pires, L.M.; Van Donk, E.

    2008-01-01

    This paper critically reviews the published works on lake restoration in north-western Europe, with the aim to highlight the causes of failures of lake biomanipulation, and to identify the main bottlenecks that have impeded progress. More importantly, we explore the prospects of applying new ecotech

  10. Maternal age effect and severe germ-line bottleneck in the inheritance of human mitochondrial DNA

    DEFF Research Database (Denmark)

    Rebolledo-Jaramillo, Boris; Su, Marcia Shu-Wei; Stoler, Nicholas;

    2014-01-01

    The manifestation of mitochondrial DNA (mtDNA) diseases depends on the frequency of heteroplasmy (the presence of several alleles in an individual), yet its transmission across generations cannot be readily predicted owing to a lack of data on the size of the mtDNA bottleneck during oogenesis. Fo...

  11. Evaluation of bottlenecks in the late stages of protein secretion in Bacillus subtilis

    NARCIS (Netherlands)

    Bolhuis, A; Tjalsma, H; Smith, H.E; Meima, R.; Venema, G; Bron, S; van Dijl, J.M

    1999-01-01

    Despite a high capacity for secretion of homologous proteins, the secretion of heterologous proteins by Bacillus subtilis is frequently inefficient. In the present studies, we have investigated and compared bottlenecks in the secretion of four heterologous proteins: Bacillus lichenifomis alpha-amyla

  12. The nocturnal bottleneck and the evolution of activity patterns in mammals

    NARCIS (Netherlands)

    Gerkema, Menno P.; Davies, Wayne I. L.; Foster, Russell G.; Menaker, Michael; Hut, Roelof A.

    2013-01-01

    In 1942, Walls described the concept of a 'nocturnal bottleneck' in placental mammals, where these species could survive only by avoiding daytime activity during times in which dinosaurs were the dominant taxon. Walls based this concept of a longer episode of nocturnality in early eutherian mammals

  13. Analysis of a generic model for a bottleneck link in an integrated services communications network

    NARCIS (Netherlands)

    Al-Begain, K.; Heindl, A.; Telek, M.; Litjens, R.; Boucherie, R.J.

    2007-01-01

    We develop and analyse a generic model for performance evaluation, parameter optimisation and dimensioning of a bottleneck link in an integrated services communications network. Possible application areas include ip, atm and gsm/gprs networks. The model enables analytical evaluation for a scenario o

  14. About the Role of the Bottleneck/Cork Interface on Oxygen Transfer.

    Science.gov (United States)

    Lagorce-Tachon, Aurélie; Karbowiak, Thomas; Paulin, Christian; Simon, Jean-Marc; Gougeon, Régis D; Bellat, Jean-Pierre

    2016-09-01

    The transfer of oxygen through a corked bottleneck was investigated using a manometric technique. First, the effect of cork compression on oxygen transfer was evaluated without considering the glass/cork interface. No significant effect of cork compression (at 23% strain, corresponding to the compression level of cork in a bottleneck for still wines) was noticeable on the effective diffusion coefficient of oxygen. The mean value of the effective diffusion coefficient is equal to 10(-8) m(2) s(-1), with a statistical distribution ranging from 10(-10) to 10(-7) m(2) s(-1), which is of the same order of magnitude as for the non-compressed cork. Then, oxygen transfer through cork compressed in a glass bottleneck was determined to assess the effect of the glass/cork interface. In the particular case of a gradient-imposed diffusion of oxygen through our model corked bottleneck system (dry cork without surface treatment; 200 and ∼0 hPa of oxygen on both sides of the sample), the mean effective diffusion coefficient is of 5 × 10(-7) m(2) s(-1), thus revealing the possible importance of the role of the glass/stopper interface in the oxygen transfer.

  15. Strategic behavior and social outcomes in a bottleneck queue: experimental evidence

    DEFF Research Database (Denmark)

    Breinbjerg, Jesper Breinbjerg; Sebald, Alexander Christopher; Østerdal, Lars Peter

    2016-01-01

    We theoretically and experimentally study the differential incentive effects of three well known queue disciplines in a strategic environment in which a bottleneck facility opens and impatient players decide when to arrive. For a class of three-player games, we derive equilibrium arrivals under...

  16. Avoiding the problem state bottleneck by strategic use of the environment

    NARCIS (Netherlands)

    Borst, Jelmer P.; Buwalda, Trudy A.; van Rijn, Hedderik; Taatgen, Niels A.

    2013-01-01

    We investigated whether environmental support can be used to circumvent the problem state bottleneck in human multitasking. Previously, it was shown that people can only maintain a single chunk of information in their problem state resource, the central part of working memory. Consequently, when the

  17. Steiner tree heuristic in the Euclidean d-space using bottleneck distances

    DEFF Research Database (Denmark)

    Lorenzen, Stephan Sloth; Winter, Pawel

    2016-01-01

    in a greedy fashion to obtain a low cost tree spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To avoid this and to obtain even better solutions, bottleneck distances are utilized to determine good subsets of terminals...

  18. Bottleneck distances and Steiner trees in the Euclidean d-space

    DEFF Research Database (Denmark)

    Winter, Pawel; Lorenzen, Stephan Sloth

    fashion to obtain low cost trees spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To obtain better solutions, bottleneck distances are utilized to determine good subsets of terminals without being constrained...

  19. Achievements & bottlenecks in humanitarian demining EU-funded research: Final results from the EC DELVE project

    NARCIS (Netherlands)

    Sahli, H.; Bruschini, C.; Kempen, L. van; Schleijpen, H.M.A.; Breejen, E. den

    2008-01-01

    The EC DELVE Support Action project has analyzed the bottlenecks in the transfer of Humanitarian Demining (HD) technology from technology development to the use in the field, and drawn some lessons learned, basing itself on the assessment of the European Humanitarian Demining Research and Technology

  20. Bottlenecks, population differentiation and apparent selection at microsatellite loci in Australian Drosophila buzzatii

    DEFF Research Database (Denmark)

    Barker, J.S.F.; Frydenberg, Jane; González, J.;

    2009-01-01

    variation for 15 microsatellite loci in each of nine populations in eastern Australia was used to estimate the size of the bottleneck, and to determine if any of these microsatellites marked genomic regions subject to recent selection. We estimate that on its introduction to Australia, D. buzzatii went...

  1. Post-bottleneck genetic diversity of elephant populations in South Africa, revealed using microsatellite analysis.

    Science.gov (United States)

    Whitehouse, A M; Harley, E H

    2001-09-01

    Widespread hunting had fragmented and severely reduced elephant populations in South Africa by 1900. Elephant numbers increased during the 1900s, although rates of recovery of individual populations varied. The Kruger National Park elephant population increased rapidly, to more than 6000 by 1967, with recruitment boosted by immigration from Mozambique. The Addo Elephant National Park population was reduced to 11 elephants in 1931 and remains relatively small (n = 325). Loss of genetic variation is expected to occur whenever a population goes through a bottleneck, especially when post-bottleneck recovery is slow. Variation at nine polymorphic microsatellite loci was analysed for Kruger and Addo elephants, as well as museum specimens of Addo elephants shot prior to the population bottleneck. Significantly reduced genetic variation and heterozygosity were observed in Addo in comparison to Kruger (mean alleles/locus and H(E): Addo 1.89, 0.18; Kruger 3.89, 0.44). Two alleles not present in the current Addo population were observed in the museum specimens. Addo elephants represent a genetic subset of the Kruger population, with high levels of genetic differentiation resulting from rapid genetic drift. The Kruger population is low in genetic diversity in comparison to East African elephants, confirming this population also suffered an appreciable bottleneck.

  2. The strength and timing of the mitochondrial bottleneck in salmon suggests a conserved mechanism in vertebrates.

    Directory of Open Access Journals (Sweden)

    Jonci N Wolff

    Full Text Available In most species mitochondrial DNA (mtDNA is inherited maternally in an apparently clonal fashion, although how this is achieved remains uncertain. Population genetic studies show not only that individuals can harbor more than one type of mtDNA (heteroplasmy but that heteroplasmy is common and widespread across a diversity of taxa. Females harboring a mixture of mtDNAs may transmit varying proportions of each mtDNA type (haplotype to their offspring. However, mtDNA variants are also observed to segregate rapidly between generations despite the high mtDNA copy number in the oocyte, which suggests a genetic bottleneck acts during mtDNA transmission. Understanding the size and timing of this bottleneck is important for interpreting population genetic relationships and for predicting the inheritance of mtDNA based disease, but despite its importance the underlying mechanisms remain unclear. Empirical studies, restricted to mice, have shown that the mtDNA bottleneck could act either at embryogenesis, oogenesis or both. To investigate whether the size and timing of the mitochondrial bottleneck is conserved between distant vertebrates, we measured the genetic variance in mtDNA heteroplasmy at three developmental stages (female, ova and fry in chinook salmon and applied a new mathematical model to estimate the number of segregating units (N(e of the mitochondrial bottleneck between each stage. Using these data we estimate values for mtDNA Ne of 88.3 for oogenesis, and 80.3 for embryogenesis. Our results confirm the presence of a mitochondrial bottleneck in fish, and show that segregation of mtDNA variation is effectively complete by the end of oogenesis. Considering the extensive differences in reproductive physiology between fish and mammals, our results suggest the mechanism underlying the mtDNA bottleneck is conserved in these distant vertebrates both in terms of it magnitude and timing. This finding may lead to improvements in our understanding of

  3. More precisely biased : increasing the number of markers is not a silver bullet in genetic bottleneck testing

    NARCIS (Netherlands)

    Peery, M. Zachariah; Reid, Brendan N.; Kirby, Rebecca; Stoelting, Ricka; Doucet-Beer, Elena; Robinson, Stacie; Vasquez-Carrillo, Catalina; Pauli, Jonathan N.; Palsboll, Per J.

    2013-01-01

    In response to our review of the use of genetic bottleneck tests in the conservation literature (Peery etal. 2012, Molecular Ecology, 21, 3403-3418), Hoban etal. (2013, Molecular Ecology, in press) conducted population genetic simulations to show that the statistical power of genetic bottleneck test

  4. 基于瓶颈多态性的生产物流瓶颈闭环预测方法%Close-loop prediction method of logistics bottleneck based on bottleneck polymorphism

    Institute of Scientific and Technical Information of China (English)

    刘志; 唐娟; 费志敏

    2012-01-01

    针对不确定性环境下的生产物流瓶颈漂移预测问题,提出一种基于瓶颈多态性的瓶颈闭环预测方法。建立灵敏型瓶颈、迟钝型瓶颈、渐向型瓶颈和渐离型瓶颈的概念,以定性描述制造系统的物流瓶颈多态性;以瓶颈指数为基础,以制造单元时问和质量为参数,构建瓶颈漂移指数数学模型,并以此为依据构建瓶颈多态性判定机制,以实现瓶颈多态性的定量描述,进而为瓶颈漂移规律的研究提供技术支持;构建包含数据统计分析、瓶颈预测机制、瓶颈多态性分析和瓶颈指数迭代预测四项内容的瓶颈闭环预测方法,以实现生产物流瓶颈的动态连续预测。通过对某汽车装配车间生产物流瓶颈的动态预测和监控,验证了该方法的有效性和准确性。%Aiming at the prediction problem of production logistics bottleneck shifting under uncertain environment, a closed-loop prediction method of bottleneck was proposed based on bottleneck polymorphisrrL The concepts of sensi- tive bottleneck, obtuse bottleneck, growing bottleneck and decreasing bottleneck were formulated to describe the lo- gistics bottleneck polymorphism of manufacturing system qualitatively. Based on bottleneck index, mathematical model of bottleneck shifting index was established by taking time and quality of manufacturing unit as parameters. Decision mechanism of bottleneck polymorphism was constructed to realize bottleneck polymorphism description on the basis of bottleneck shifting index quantitatively, which provided technological support for studying on bottleneck shifting rule. The bottleneck closed-loop prediction method which was composed of data statistic analysis, bottle- neck prediction mechanism, bottleneck polymorphism analysis and bottleneck index iterative prediction was founded to realize dynamic and continuous prediction of production logistics bottleneck. An example of dynamically forecas- ting

  5. 基于两种瓶颈度的制造车间多瓶颈动态预测方法%Dynamic Prediction Method of Multi-bottleneck in Manufacturing Shop Based on Two Bottleneck Degrees

    Institute of Scientific and Technical Information of China (English)

    刘志; 蒋增强; 龚本刚

    2014-01-01

    针对制造车间多瓶颈预测问题,提出一种基于两种瓶颈度的多瓶颈动态预测方法,以在合理认定瓶颈责任的前提下实现系统多瓶颈的连续准确预测。首先,建立综合瓶颈度和独立瓶颈度的概念模型,并以时间、质量和成本为参数,构建其数学模型;然后,构建包含多瓶颈双层预测机制、瓶颈多态性分析和瓶颈指数迭代预测模型的多瓶颈动态预测方法;最后,将多瓶颈动态预测方法、单瓶颈度法和PBM 法运用至某汽车产品总装线,以验证该方法有效性。%Aiming at the prediction problem of multi-bottleneck in complex manufacturing shop , a dynamic prediction method of multi-bottleneck was proposed based on two bottleneck degrees ,which can forecast bottleneck accurately under conditions that bottleneck responsibility was verified reasona-bly .Firstly ,conceptual models about general bottleneck degree and independent bottleneck degree were built ,and then taking time ,quality and cost as parameters ,their mathematical models were es-tablished .Secondly ,one dynamic prediction method of multi-bottleneck was come up with ,which con-tained dual-layer multi-bottleneck prediction mechanism ,bottleneck polymorphism analysis and the it-erative prediction of bottleneck index .Finally ,it is proved to be superior and credible by comparison to the method of single bottleneck degree and the method of PBM for production bottleneck prediction problem of one vehicle assembly line .

  6. Squeezing through the Now-or-Never bottleneck: Reconnecting language processing, acquisition, change, and structure.

    Science.gov (United States)

    Chater, Nick; Christiansen, Morten H

    2016-01-01

    If human language must be squeezed through a narrow cognitive bottleneck, what are the implications for language processing, acquisition, change, and structure? In our target article, we suggested that the implications are far-reaching and form the basis of an integrated account of many apparently unconnected aspects of language and language processing, as well as suggesting revision of many existing theoretical accounts. With some exceptions, commentators were generally supportive both of the existence of the bottleneck and its potential implications. Many commentators suggested additional theoretical and linguistic nuances and extensions, links with prior work, and relevant computational and neuroscientific considerations; some argued for related but distinct viewpoints; a few, though, felt traditional perspectives were being abandoned too readily. Our response attempts to build on the many suggestions raised by the commentators and to engage constructively with challenges to our approach.

  7. Zero-temperature quantum annealing bottlenecks in the spin-glass phase.

    Science.gov (United States)

    Knysh, Sergey

    2016-08-05

    A promising approach to solving hard binary optimization problems is quantum adiabatic annealing in a transverse magnetic field. An instantaneous ground state-initially a symmetric superposition of all possible assignments of N qubits-is closely tracked as it becomes more and more localized near the global minimum of the classical energy. Regions where the energy gap to excited states is small (for instance at the phase transition) are the algorithm's bottlenecks. Here I show how for large problems the complexity becomes dominated by O(log N) bottlenecks inside the spin-glass phase, where the gap scales as a stretched exponential. For smaller N, only the gap at the critical point is relevant, where it scales polynomially, as long as the phase transition is second order. This phenomenon is demonstrated rigorously for the two-pattern Gaussian Hopfield model. Qualitative comparison with the Sherrington-Kirkpatrick model leads to similar conclusions.

  8. Rapid Mitochondrial DNA Segregation in Primate Preimplantation Embryos Precedes Somatic and Germline Bottleneck

    Directory of Open Access Journals (Sweden)

    Hyo-Sang Lee

    2012-05-01

    Full Text Available The timing and mechanisms of mitochondrial DNA (mtDNA segregation and transmission in mammals are poorly understood. Genetic bottleneck in female germ cells has been proposed as the main phenomenon responsible for rapid intergenerational segregation of heteroplasmic mtDNA. We demonstrate here that mtDNA segregation occurs during primate preimplantation embryogenesis resulting in partitioning of mtDNA variants between daughter blastomeres. A substantial shift toward homoplasmy occurred in fetuses and embryonic stem cells (ESCs derived from these heteroplasmic embryos. We also observed a wide range of heteroplasmic mtDNA variants distributed in individual oocytes recovered from these fetuses. Thus, we present here evidence for a previously unknown mtDNA segregation and bottleneck during preimplantation embryo development, suggesting that return to the homoplasmic condition can occur during development of an individual organism from the zygote to birth, without a passage through the germline.

  9. Rapid mitochondrial DNA segregation in primate preimplantation embryos precedes somatic and germline bottleneck.

    Science.gov (United States)

    Lee, Hyo-Sang; Ma, Hong; Juanes, Rita Cervera; Tachibana, Masahito; Sparman, Michelle; Woodward, Joy; Ramsey, Cathy; Xu, Jing; Kang, Eun-Ju; Amato, Paula; Mair, Georg; Steinborn, Ralf; Mitalipov, Shoukhrat

    2012-05-31

    The timing and mechanisms of mitochondrial DNA (mtDNA) segregation and transmission in mammals are poorly understood. Genetic bottleneck in female germ cells has been proposed as the main phenomenon responsible for rapid intergenerational segregation of heteroplasmic mtDNA. We demonstrate here that mtDNA segregation occurs during primate preimplantation embryogenesis resulting in partitioning of mtDNA variants between daughter blastomeres. A substantial shift toward homoplasmy occurred in fetuses and embryonic stem cells (ESCs) derived from these heteroplasmic embryos. We also observed a wide range of heteroplasmic mtDNA variants distributed in individual oocytes recovered from these fetuses. Thus, we present here evidence for a previously unknown mtDNA segregation and bottleneck during preimplantation embryo development, suggesting that return to the homoplasmic condition can occur during development of an individual organism from the zygote to birth, without a passage through the germline.

  10. The bottleneck 2-connected $k$-Steiner network problem for $k\\leq 2$

    CERN Document Server

    Brazil, M; Thomas, D A

    2011-01-01

    The geometric bottleneck Steiner network problem on a set of vertices $X$ embedded in a normed plane requires one to construct a graph $G$ spanning $X$ and a variable set of $k\\geq 0$ additional points, such that the length of the longest edge is minimised. If no other constraints are placed on $G$ then a solution always exists which is a tree. In this paper we consider the Euclidean bottleneck Steiner network problem for $k\\leq 2$, where $G$ is constrained to be 2-connected. By taking advantage of relative neighbourhood graphs, Voronoi diagrams, and the tree structure of block cut-vertex decompositions of graphs, we produce exact algorithms of complexity $O(n^2)$ and $O(n^2\\log n)$ for the cases $k=1$ and $k=2$ respectively. Our algorithms can also be extended to other norms such as the $L_p$ planes.

  11. Zero-temperature quantum annealing bottlenecks in the spin-glass phase

    Science.gov (United States)

    Knysh, Sergey

    2016-08-01

    A promising approach to solving hard binary optimization problems is quantum adiabatic annealing in a transverse magnetic field. An instantaneous ground state--initially a symmetric superposition of all possible assignments of N qubits--is closely tracked as it becomes more and more localized near the global minimum of the classical energy. Regions where the energy gap to excited states is small (for instance at the phase transition) are the algorithm's bottlenecks. Here I show how for large problems the complexity becomes dominated by O(log N) bottlenecks inside the spin-glass phase, where the gap scales as a stretched exponential. For smaller N, only the gap at the critical point is relevant, where it scales polynomially, as long as the phase transition is second order. This phenomenon is demonstrated rigorously for the two-pattern Gaussian Hopfield model. Qualitative comparison with the Sherrington-Kirkpatrick model leads to similar conclusions.

  12. Bottleneck of Farmers’ Quality in New Socialist Countryside Construction and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    We analyzed problems of farmers’ quality in the new socialist countryside construction,including low educational level,poor specialized skills,and low ideological and ethical quality.These problems become bottleneck of the socialist countryside construction.In view of these problems,we put forward following countermeasures:speeding up urbanization development,consolidating rural basic education,strengthening rural vocational education,and developing new approaches to improve farmers’ ideological and ethical quality.

  13. An assessment of The Capacity Drops at The Bottleneck Segments: A review on the existing methodologies

    Directory of Open Access Journals (Sweden)

    Sugiarto Sugiarto

    2015-08-01

    Full Text Available The term of capacity is very useful to quantify the ability of transport facilities in terms of carrying traffic. The capacity of the road is an essential ingredient in the planning, design, and operation of roadways. It is desirable for traffic analyst to be able to predict the time and places where congestion will occur and the volumes to be expected. Most of urbanized areas have been experiencing of traffic congestion problems particularly at urban arterial systems. High traffic demand and limited supply of roadways are always the main factors produced traffic congestion. However, there are other sources of local and temporal congestion, such as uncontrolled access point, median opening and on-street parking activities, which are caused a reduction of roadway capacity during peak operations. Those locations could result in reduction of travel speed and road, as known as hidden bottlenecks. This is bottleneck which is without any changes in geometric of the segments. The Indonesian Highway Capacity Manual (IHCM, 1997 is used to assess urban arterial systems till current days. IHCM provides a static method for examining the capacityand does not systematically take into account of bottleneck activities. However, bottleneck activities create interruption smooth traffic flow along arterial streets, which in turns stimulate related problems, such as, excessive air pollution, additional energy consumption and driver’s frustration due to traffic jammed. This condition could happen simultaneously; mostly repetitive and predictable in same peak hour demands. Therefore, this paper carefully summarize on the existing methodologies considering required data, handled data processing and expected output of each proposed of analysis. We further notice that dynamic approach could be more appropriated for analyzing temporal congestion segments (median opening, on street parking, etc.. Method of oblique cumulative plot seems to be more applicable in terms of

  14. Mine production index (MPI)-extension of OEE for bottleneck detection in mining

    Institute of Scientific and Technical Information of China (English)

    Amol Arun Lanke; Seyed Hadi Hoseinie; Behzad Ghodrati

    2016-01-01

    Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine effectiveness. Mining literatures on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three param-eters are useful for evaluating effectiveness of equipment. Mine production index (MPI), which can rep-resent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of MPI. The results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach, an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.

  15. Bottleneck genes and community structure in the cell cycle network of S. pombe.

    Directory of Open Access Journals (Sweden)

    Cécile Caretta-Cartozo

    2007-06-01

    Full Text Available The identification of cell cycle-related genes is still a difficult task, even for organisms with relatively few genes such as the fission yeast. Several gene expression studies have been published on S. pombe showing similarities but also discrepancies in their results. We introduce a network in which the weight of each link is a function of the phase difference between the expression peaks of two genes. The analysis of the stability of the clustering through the computation of an entropy parameter reveals a structure made of four clusters, the first one corresponding to a robustly connected M-G1 component, the second to genes in the S phase, and the third and fourth to two G2 components. They are separated by bottleneck structures that appear to correspond to cell cycle checkpoints. We identify a number of genes that are located on these bottlenecks. They represent a novel group of cell cycle regulatory genes. They all show interesting functions, and they are supposed to be involved in the regulation of the transition from one phase to the next. We therefore present a comparison of the available studies on the fission yeast cell cycle and a general statistical bioinformatics methodology to find bottlenecks and gene community structures based on recent developments in network theory.

  16. Lagrangian-averaged model for magnetohydrodynamic turbulence and the absence of bottlenecks.

    Science.gov (United States)

    Pietarila Graham, Jonathan; Mininni, Pablo D; Pouquet, Annick

    2009-07-01

    We demonstrate that, for the case of quasiequipartition between the velocity and the magnetic field, the Lagrangian-averaged magnetohydrodynamics (LAMHD) alpha model reproduces well both the large-scale and the small-scale properties of turbulent flows; in particular, it displays no increased (superfilter) bottleneck effect with its ensuing enhanced energy spectrum at the onset of the subfilter scales. This is in contrast to the case of the neutral fluid in which the Lagrangian-averaged Navier-Stokes alpha model is somewhat limited in its applications because of the formation of spatial regions with no internal degrees of freedom and subsequent contamination of superfilter-scale spectral properties. We argue that, as the Lorentz force breaks the conservation of circulation and enables spectrally nonlocal energy transfer (associated with Alfvén waves), it is responsible for the absence of a viscous bottleneck in magnetohydrodynamics (MHD), as compared to the fluid case. As LAMHD preserves Alfvén waves and the circulation properties of MHD, there is also no (superfilter) bottleneck found in LAMHD, making this method capable of large reductions in required numerical degrees of freedom; specifically, we find a reduction factor of approximately 200 when compared to a direct numerical simulation on a large grid of 1536;{3} points at the same Reynolds number.

  17. The nocturnal bottleneck and the evolution of activity patterns in mammals.

    Science.gov (United States)

    Gerkema, Menno P; Davies, Wayne I L; Foster, Russell G; Menaker, Michael; Hut, Roelof A

    2013-08-22

    In 1942, Walls described the concept of a 'nocturnal bottleneck' in placental mammals, where these species could survive only by avoiding daytime activity during times in which dinosaurs were the dominant taxon. Walls based this concept of a longer episode of nocturnality in early eutherian mammals by comparing the visual systems of reptiles, birds and all three extant taxa of the mammalian lineage, namely the monotremes, marsupials (now included in the metatherians) and placentals (included in the eutherians). This review describes the status of what has become known as the nocturnal bottleneck hypothesis, giving an overview of the chronobiological patterns of activity. We review the ecological plausibility that the activity patterns of (early) eutherian mammals were restricted to the night, based on arguments relating to endothermia, energy balance, foraging and predation, taking into account recent palaeontological information. We also assess genes, relating to light detection (visual and non-visual systems) and the photolyase DNA protection system that were lost in the eutherian mammalian lineage. Our conclusion presently is that arguments in favour of the nocturnal bottleneck hypothesis in eutherians prevail.

  18. Managing bottlenecks in manual automobile assembly systems using discrete event simulation

    Directory of Open Access Journals (Sweden)

    Dewa, M.

    2013-08-01

    Full Text Available Batch model lines are quite handy when the demand for each product is moderate. However, they are characterised by high work-in-progress inventories, lost production time when changing over models, and reduced flexibility when it comes to altering production rates as product demand changes. On the other hand, mixed model lines can offer reduced work-in-progress inventory and increased flexibility. The object of this paper is to illustrate that a manual automobile assembling system can be optimised through managing bottlenecks by ensuring high workstation utilisation, reducing queue lengths before stations and reducing station downtime. A case study from the automobile industry is used for data collection. A model is developed through the use of simulation software. The model is then verified and validated before a detailed bottleneck analysis is conducted. An operational strategy is then proposed for optimal bottleneck management. Although the paper focuses on improving automobile assembly systems in batch mode, the methodology can also be applied in single model manual and automated production lines.

  19. On the prospect of identifying adaptive loci in recently bottlenecked populations.

    Directory of Open Access Journals (Sweden)

    Yu-Ping Poh

    Full Text Available Identifying adaptively important loci in recently bottlenecked populations - be it natural selection acting on a population following the colonization of novel habitats in the wild, or artificial selection during the domestication of a breed - remains a major challenge. Here we report the results of a simulation study examining the performance of available population-genetic tools for identifying genomic regions under selection. To illustrate our findings, we examined the interplay between selection and demography in two species of Peromyscus mice, for which we have independent evidence of selection acting on phenotype as well as functional evidence identifying the underlying genotype. With this unusual information, we tested whether population-genetic-based approaches could have been utilized to identify the adaptive locus. Contrary to published claims, we conclude that the use of the background site frequency spectrum as a null model is largely ineffective in bottlenecked populations. Results are quantified both for site frequency spectrum and linkage disequilibrium-based predictions, and are found to hold true across a large parameter space that encompasses many species and populations currently under study. These results suggest that the genomic footprint left by selection on both new and standing variation in strongly bottlenecked populations will be difficult, if not impossible, to find using current approaches.

  20. Incident and Traffic-Bottleneck Detection Algorithm in High-Resolution Remote Sensing Imagery

    Directory of Open Access Journals (Sweden)

    S.M.M. Kahaki

    2012-09-01

    Full Text Available One of the most important methods to solve traffic congestion is to detect the incident state of a roadway. This paper describes the development of a method for road traffic monitoring aimed at the acquisition and analysis of remote sensing imagery. We propose a strategy for road extraction, vehicle detection and incident detection from remote sensing imagery using techniques based on neural networks, Radon transform for angle detection and traffic-flow measurements. Traffic-bottleneck detection is another method that is proposed for recognizing incidents in both offline and real-time mode. Traffic flows and incidents are extracted from aerial images of bottleneck zones. The results show that the proposed approach has a reasonable detection performance compared to other methods. The best performance of the learning system was a detection rate of 87% and a false alarm rate of less than 18% on 45 aerial images of roadways. The performance of the traffic-bottleneck detection method had a detection rate of 87.5%.

  1. Incident and Traffic-Bottleneck Detection Algorithm in High-Resolution Remote Sensing Imagery

    Directory of Open Access Journals (Sweden)

    Sayed M.M. Kahaki

    2013-09-01

    Full Text Available One  of  the  most  important  methods  to  solve  traffic  congestion  is  to detect the incident state of a roadway. This paper describes the development of a method  for  road  traffic  monitoring  aimed  at  the  acquisition  and  analysis  of remote  sensing  imagery.  We  propose  a  strategy  for  road  extraction,  vehicle detection  and incident detection  from remote sensing imagery using techniques based on neural networks, Radon transform  for angle detection and traffic-flow measurements.  Traffic-bottleneck  detection  is  another  method  that  is  proposed for recognizing incidents in both offline and real-time mode. Traffic flows and incidents are extracted from aerial images of bottleneck zones. The results show that the proposed approach has a reasonable detection performance compared to other methods. The best performance of the learning system was a detection rate of 87% and a false alarm rate of less than 18% on 45 aerial images of roadways. The performance of the traffic-bottleneck detection  method had a detection rate of 87.5%.

  2. Empirical Features of Spontaneous and Induced Traffic Breakdowns in Free Flow at Highway Bottlenecks

    CERN Document Server

    Kerner, Boris S; Klenov, Sergey L; Rehborn, Hubert; Leibel, Michael

    2015-01-01

    Based on an empirical study of real field traffic data measured in 1996--2014 through road detectors installed on German freeways, we reveal physical features of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks. It is shown that the source of a nucleus for traffic breakdown is the solely difference between empirical spontaneous and induced traffic breakdowns at a highway bottleneck. Microscopic traffic simulations with a stochastic traffic flow model in the framework of three-phase theory explain the empirical findings. It turns out that in the most cases, a nucleus for empirical spontaneous traffic breakdown occurs through an interaction of one of waves in free flow with an empirical permanent speed disturbance localized at a highway bottleneck. The wave is a localized structure in free flow, in which the total flow rate is larger and the speed averaged across the highway is smaller than outside the wave. The waves in free flow appear due to oscilations in the percentage...

  3. BOTTLENECK ANALYSIS AND STRATEGIC PLANNING ON CHILDHOOD DIARRHEA MANAGEMENT IN 6 HIGH PRIORITY DISTRICTS OF GUJARAT

    Directory of Open Access Journals (Sweden)

    Rupani Mihir

    2015-01-01

    Full Text Available Introduction:Bottleneck Analysis and Strategic Planning exercise was carried out in 6 High Priority Districts (HPDs, under Call-to-Action for RMNCH+A strategy.Rationale: In spite of continued efforts, India is still lagging behind in its MDG goals.Objectives: To identify gaps in childhood diarrhea management and propose strategic options for the same.Materials and Methods: Bottleneck analysis exercisewas carried out based on the Tanahashi model, desk review and focused group discussions between district officials, front-line workers and UNICEF officials. These bottlenecks were pertaining to the availability, accessibility, utilization of services and quality of services being provided by the health department.Elaborating the Tanahashi model for the 6 HPDs, 94% of the front-line workers (FLWs had stock of Zinc-ORS; 88% FLWs were trained in diarrhea management; 98% villages had at least one FLW trained in diarrhea management; health care seeking for diarrhea cases was 17%; 5.1% diarrhea cases received Zinc-ORS from health worker and 2.4% care takers prepared Zinc-ORS in safe drinking water.Results: The major bottlenecks identified for Childhood Diarrhea management in the 6 High Priority Districts were poor demand generation, unsafe drinking water, poor access to improved sanitation facility and lack of equitable distribution of Zinc-ORS till the front-line worker level. The main strategic options that were suggested for relieving these bottlenecks were Zinc-ORS roll out in scale-up districts, develop IEC/BCC plan for childhood diarrhea management at state/district level, use of Drug Logistics Information Management System (DLIMS software for supply chain management of Zinc-ORS, strengthening of chlorination activity at household level, monitoring implementation of Nirmal Bharat Abhiyaan (NBA for constructing improved sanitation facilities at household level and to develop an IEC/BCC plan for hygiene promotion and usage of sanitary latrines

  4. Bottleneck Prediction Method Based on Improved Adaptive Network-based Fuzzy Inference System (ANFIS) in Semiconductor Manufacturing System%Bottleneck Prediction Method Based on Improved Adaptive Network-based Fuzzy Inference System (ANFIS) in Semiconductor Manufacturing System

    Institute of Scientific and Technical Information of China (English)

    曹政才; 邓积杰; 刘民; 王永吉

    2012-01-01

    Semiconductor manufacturing (SM) system is one of the most complicated hybrid processes involved continuously variable dynamical systems and discrete event dynamical systems. The optimization and scheduling of semiconductor fabrication has long been a hot research direction in automation. Bottleneck is the key factor to a SM system, which seriously influences the throughput rate, cycle time, time-delivery rate, etc. Efficient prediction for the bottleneck of a SM system provides the best support for the consequent scheduling. Because categorical data (product types, releasing strategies) and numerical data (work in process, processing time, utilization rate, buffer length, etc.) have significant effect on bottleneck, an improved adaptive network-based fuzzy inference system (ANFIS) was adopted in this study to predict bottleneck since conventional neural network-based methods accommodate only numerical inputs. In this improved ANFIS, the contribution of categorical inputs to firing strength is reflected through a transformation matrix. In order to tackle high-dimensional inputs, reduce the number of fuzzy rules and obtain high prediction accuracy, a fuzzy c-means method combining binary tree linear division method was applied to identify the initial structure of fuzzy inference system. According to the experimental results, the main-bottleneck and sub-bottleneck of SM system can be predicted accurately with the proposed method.

  5. Anatomy of a bottleneck: diagnosing factors limiting population growth in the Puerto Rican parrot

    Science.gov (United States)

    Beissenger, S.R.; Wunderle, J.M.; Meyers, J.M.; Saether, B.-E.; Engen, S.

    2008-01-01

    The relative importance of genetic, demographic, environmental, and catastrophic processes that maintain population bottlenecks has received little consideration. We evaluate the role of these factors in maintaining the Puerto Rican Parrot (Amazona vittata) in a prolonged bottleneck from 1973 through 2000 despite intensive conservation efforts. We first conduct a risk analysis, then examine evidence for the importance of specific processes maintaining the bottleneck using the multiple competing hypotheses approach, and finally integrate these results through a sensitivity analysis of a demographic model using life-stage simulation analysis (LSA) to determine the relative importance of genetic, demographic, environmental, and catastrophic processes on population growth. Annual population growth has been slow and variable (1.0 6 5.2 parrots per year, or an average k?1.05 6 0.19) from 16 parrots (1973) to a high of 40-42 birds (1997-1998). A risk analysis based on population prediction intervals (PPI) indicates great risk and large uncertainty, with a range of 22?83 birds in the 90% PPI only five years into the future. Four primary factors (reduced hatching success due to inbreeding, failure of adults to nest, nest failure due to nongenetic causes, and reduced survival of adults and juveniles) were responsible for maintaining the bottleneck. Egghatchability rates were low (70.6% per egg and 76.8% per pair), and hatchability increased after mate changes, suggesting inbreeding effects. Only an average of 34% of the population nested annually, which was well below the percentage of adults that should have reached an age of first breeding (41-56%). This chronic failure to nest appears to have been caused primarily by environmental and/or behavioral factors, and not by nest-site scarcity or a skewed sex ratio. Nest failure rates from nongenetic causes (i.e., predation, parasitism, and wet cavities) were low (29%) due to active management (protecting nests and fostering

  6. Laboratory colonisation and genetic bottlenecks in the tsetse fly Glossina pallidipes.

    Directory of Open Access Journals (Sweden)

    Marc Ciosi

    2014-02-01

    Full Text Available BACKGROUND: The IAEA colony is the only one available for mass rearing of Glossina pallidipes, a vector of human and animal African trypanosomiasis in eastern Africa. This colony is the source for Sterile Insect Technique (SIT programs in East Africa. The source population of this colony is unclear and its genetic diversity has not previously been evaluated and compared to field populations. METHODOLOGY/PRINCIPAL FINDINGS: We examined the genetic variation within and between the IAEA colony and its potential source populations in north Zimbabwe and the Kenya/Uganda border at 9 microsatellites loci to retrace the demographic history of the IAEA colony. We performed classical population genetics analyses and also combined historical and genetic data in a quantitative analysis using Approximate Bayesian Computation (ABC. There is no evidence of introgression from the north Zimbabwean population into the IAEA colony. Moreover, the ABC analyses revealed that the foundation and establishment of the colony was associated with a genetic bottleneck that has resulted in a loss of 35.7% of alleles and 54% of expected heterozygosity compared to its source population. Also, we show that tsetse control carried out in the 1990's is likely reduced the effective population size of the Kenya/Uganda border population. CONCLUSIONS/SIGNIFICANCE: All the analyses indicate that the area of origin of the IAEA colony is the Kenya/Uganda border and that a genetic bottleneck was associated with the foundation and establishment of the colony. Genetic diversity associated with traits that are important for SIT may potentially have been lost during this genetic bottleneck which could lead to a suboptimal competitiveness of the colony males in the field. The genetic diversity of the colony is lower than that of field populations and so, studies using colony flies should be interpreted with caution when drawing general conclusions about G. pallidipes biology.

  7. Bottleneck analysis and strategic planning using Tanahashi model for childhood diarrhea management in Gujarat, Western India.

    Science.gov (United States)

    Rupani, Mihir Prafulbhai; Gaonkar, Narayan T; Bhatt, Gneyaa S

    2016-10-01

    In spite of continued efforts, India is still lagging behind in achieving its MDG goals. The objectives of this study were to identify stake-holders who have a role to play in childhood diarrhea management, to identify gaps in childhood diarrhea management and to propose strategic options for relieving these gaps. Bottleneck analysis exercise was carried out based on the Tanahashi model in six High Priority Districts (HPDs) of Gujarat in period between July-November 2013. The major bottlenecks identified for Childhood Diarrhea management were poor demand generation, unsafe drinking water, poor access to improved sanitation facility and lack of equitable distribution and replenishment mechanisms for Oral Rehydration Solution (ORS) packets and Zinc tablets till the front-line worker level. The main strategic options that were suggested for relieving these bottlenecks were Zinc-ORS roll out in scale-up districts, develop Information Education Communication/Behaviour Change Communication (IEC/BCC) plan for childhood diarrhea management at state/district level, use of Drug Logistics Information Management System (DLIMS) software for supply chain management of Zinc-ORS, strengthening of chlorination activity at household level, monitoring implementation of Nirmal Bharat Abhiyaan (NBA) for constructing improved sanitation facilities at household level and to develop an IEC/BCC plan for hygiene promotion and usage of sanitary latrines. Use of Zinc tablets need to be intensified through an effective scale-up. Adequate demand generation activity is needed. There is need to address safe drinking water and improved sanitation measures at household levels. Multi-sectoral engagements and ownership of Zinc-ORS program is the need of the hour.

  8. Maternal age effect and severe germ-line bottleneck in the inheritance of human mitochondrial DNA.

    Science.gov (United States)

    Rebolledo-Jaramillo, Boris; Su, Marcia Shu-Wei; Stoler, Nicholas; McElhoe, Jennifer A; Dickins, Benjamin; Blankenberg, Daniel; Korneliussen, Thorfinn S; Chiaromonte, Francesca; Nielsen, Rasmus; Holland, Mitchell M; Paul, Ian M; Nekrutenko, Anton; Makova, Kateryna D

    2014-10-28

    The manifestation of mitochondrial DNA (mtDNA) diseases depends on the frequency of heteroplasmy (the presence of several alleles in an individual), yet its transmission across generations cannot be readily predicted owing to a lack of data on the size of the mtDNA bottleneck during oogenesis. For deleterious heteroplasmies, a severe bottleneck may abruptly transform a benign (low) frequency in a mother into a disease-causing (high) frequency in her child. Here we present a high-resolution study of heteroplasmy transmission conducted on blood and buccal mtDNA of 39 healthy mother-child pairs of European ancestry (a total of 156 samples, each sequenced at ∼20,000× per site). On average, each individual carried one heteroplasmy, and one in eight individuals carried a disease-associated heteroplasmy, with minor allele frequency ≥1%. We observed frequent drastic heteroplasmy frequency shifts between generations and estimated the effective size of the germ-line mtDNA bottleneck at only ∼30-35 (interquartile range from 9 to 141). Accounting for heteroplasmies, we estimated the mtDNA germ-line mutation rate at 1.3 × 10(-8) (interquartile range from 4.2 × 10(-9) to 4.1 × 10(-8)) mutations per site per year, an order of magnitude higher than for nuclear DNA. Notably, we found a positive association between the number of heteroplasmies in a child and maternal age at fertilization, likely attributable to oocyte aging. This study also took advantage of droplet digital PCR (ddPCR) to validate heteroplasmies and confirm a de novo mutation. Our results can be used to predict the transmission of disease-causing mtDNA variants and illuminate evolutionary dynamics of the mitochondrial genome.

  9. Direct structural mapping of organic field-effect transistors reveals bottlenecks to carrier transport

    KAUST Repository

    Li, Ruipeng

    2012-08-10

    X-ray microbeam scattering is used to map the microstructure of the organic semiconductor along the channel length of solution-processed bottom-contact OFET devices. Contact-induced nucleation is known to influence the crystallization behavior within the channel. We find that microstructural inhomogeneities in the center of the channel act as a bottleneck to charge transport. This problem can be overcome by controlling crystallization of the preferable texture, thus favoring more efficient charge transport throughout the channel. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Phonon bottleneck in GaAs/AlxGa1−xAs quantum dots

    Directory of Open Access Journals (Sweden)

    Y. C. Chang

    2015-06-01

    Full Text Available We report low-temperature photoluminescence measurements on highly-uniform GaAs/AlxGa1−xAs quantum dots grown by droplet epitaxy. Recombination between confined electrons and holes bound to carbon acceptors in the dots allow us to determine the energies of the confined states in the system, as confirmed by effective mass calculations. The presence of acceptor-bound holes in the quantum dots gives rise to a striking observation of the phonon-bottleneck effect.

  11. Breaking CFD Bottlenecks in Gas-Turbine Flow-Path Design

    Science.gov (United States)

    Davis, Roger L.; Dannenhoffer, John F., III; Clark, John P.

    2010-01-01

    New ideas are forthcoming to break existing bottlenecks in using CFD during design. CAD-based automated grid generation. Multi-disciplinary use of embedded, overset grids to eliminate complex gridding problems. Use of time-averaged detached-eddy simulations as norm instead of "steady" RANS to include effects of self-excited unsteadiness. Combined GPU/Core parallel computing to provide over an order of magnitude increase in performance/price ratio. Gas-turbine applications are shown here but these ideas can be used for other Air Force, Navy, and NASA applications.

  12. Steiner tree heuristic in the Euclidean d-space using bottleneck distances

    DEFF Research Database (Denmark)

    Lorenzen, Stephan Sloth; Winter, Pawel

    2016-01-01

    Some of the most efficient heuristics for the Euclidean Steiner minimal tree problem in the d-dimensional space, d ≥2, use Delaunay tessellations and minimum spanning trees to determine small subsets of geometrically close terminals. Their low-cost Steiner trees are determined and concatenated...... in a greedy fashion to obtain a low cost tree spanning all terminals. The weakness of this approach is that obtained solutions are topologically related to minimum spanning trees. To avoid this and to obtain even better solutions, bottleneck distances are utilized to determine good subsets of terminals...... without being constrained by the topologies of minimum spanning trees. Computational experiments show a significant solution quality improvement....

  13. [Bottlenecks in the provision of inpatient care--caused by the Hospital Funding Act].

    Science.gov (United States)

    Jansen, Christoph

    2010-01-01

    The responsibility of the state for ensuring the provision of hospital care services to its citizens derives from the welfare state principle laid down in Sect. 20 para. 1 GG (Grundgesetz, i.e., the German constitutional law). The state fulfils this responsibility by means of planning and funding regulations in the Hospital Funding Act (KHG), the Hospital Remuneration Act (KHEntG), the National Ordinance on Hospital Rates (BPflV), the Hospital Laws of the German federal states and other supplementary legislation. The funding of hospitals is based on a dual funding system, meaning that hospital investment costs generally need to be borne by the German federal states as required, while operating costs will have to be funded through the remuneration for hospital treatments. Because of the tight budget situation of the German federal states a considerable backlog of investment has built up. After a transition period (between 2005 and 2009) operating costs are now funded on the basis of the so-called DRG system (DRG=Diagnosis Related Groups)--irrespective of the actual costs incurred by each individual hospital, which has led to a commodification of hospital care services. Whether this commodification avoids bottlenecks in the provision of health services to hospital patients or creates additional bottlenecks, is a controversial issue.

  14. Topological-based bottleneck analysis and improvement strategies for traffic networks

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A method is proposed to find key components of traffic networks with homogenous and heterogeneous topologies, in which heavier traffic flow is transported. One component, called the skeleton, is the minimum spanning tree (MST) based on the zero flow cost (ZCMST). The other component is the infinite incipient percolation cluster (IIC) which represents the spine of the traffic network. Then, a new method to analysis the property of the bottleneck in a large scale traffic network is given from a macroscopic and statistical viewpoint. Moreover, three effective strategies are proposed to alleviate traffic congestion. The significance of the findings is that one can significantly improve the global transport by enhancing the capacity in the ZCMST with a few links, while for improving the local traffic property, improving a tiny fraction of the traffic network in the IIC is effective. The result can be used to help traffic managers prevent and alleviate traffic congestion in time, guard against the formation of congestion bottleneck, and make appropriate policies for traffic demand management. Meanwhile, the method has very important theoretical significance and practical worthiness in optimizing traffic organization, traffic control, and disposal of emergency.

  15. A Based-Bottleneck Multiple Vehicle Type Dynamic Marginal Cost Model and Algorithm

    Directory of Open Access Journals (Sweden)

    Shuguang Li

    2012-09-01

    Full Text Available Single vehicle type dynamic marginal cost model is extended to multiple vehicle type dynamic one based on time-dependent multiple vehicle type queue analysis at a bottleneck. A dynamic link model is presented to model interactions between cars and trucks, given the link consists of two distinct segments. The first segment is the running segment on which cars (trucks run at their free-flow speeds and the second segment is the exit queue segment. A car or a truck is assumed to be a point without length. The class-specific pi parameter is used to transform the effect of truck into passenger car equivalents, so the exit flow of cars and trucks can be calculated according to the exit capacity of a bottleneck. The analytic expression of multiple vehicle type dynamic marginal cost function is deduced under congested and uncongested conditions. Then a heuristic algorithm is presented in solving multiple vehicle type dynamic queues, tolls under system optimum and user equilibrium conditions. The numerical example illustrates the simplicity and applicability of the proposed approach.

  16. The nocturnal bottleneck and the evolution of activity patterns in mammals

    Science.gov (United States)

    Gerkema, Menno P.; Davies, Wayne I. L.; Foster, Russell G.; Menaker, Michael; Hut, Roelof A.

    2013-01-01

    In 1942, Walls described the concept of a ‘nocturnal bottleneck’ in placental mammals, where these species could survive only by avoiding daytime activity during times in which dinosaurs were the dominant taxon. Walls based this concept of a longer episode of nocturnality in early eutherian mammals by comparing the visual systems of reptiles, birds and all three extant taxa of the mammalian lineage, namely the monotremes, marsupials (now included in the metatherians) and placentals (included in the eutherians). This review describes the status of what has become known as the nocturnal bottleneck hypothesis, giving an overview of the chronobiological patterns of activity. We review the ecological plausibility that the activity patterns of (early) eutherian mammals were restricted to the night, based on arguments relating to endothermia, energy balance, foraging and predation, taking into account recent palaeontological information. We also assess genes, relating to light detection (visual and non-visual systems) and the photolyase DNA protection system that were lost in the eutherian mammalian lineage. Our conclusion presently is that arguments in favour of the nocturnal bottleneck hypothesis in eutherians prevail. PMID:23825205

  17. Identification and validation of Ifit1 as an important innate immune bottleneck.

    Directory of Open Access Journals (Sweden)

    Jason E McDermott

    Full Text Available The innate immune system plays important roles in a number of disparate processes. Foremost, innate immunity is a first responder to invasion by pathogens and triggers early defensive responses and recruits the adaptive immune system. The innate immune system also responds to endogenous damage signals that arise from tissue injury. Recently it has been found that innate immunity plays an important role in neuroprotection against ischemic stroke through the activation of the primary innate immune receptors, Toll-like receptors (TLRs. Using several large-scale transcriptomic data sets from mouse and mouse macrophage studies we identified targets predicted to be important in controlling innate immune processes initiated by TLR activation. Targets were identified as genes with high betweenness centrality, so-called bottlenecks, in networks inferred from statistical associations between gene expression patterns. A small set of putative bottlenecks were identified in each of the data sets investigated including interferon-stimulated genes (Ifit1, Ifi47, Tgtp and Oasl2 as well as genes uncharacterized in immune responses (Axud1 and Ppp1r15a. We further validated one of these targets, Ifit1, in mouse macrophages by showing that silencing it suppresses induction of predicted downstream genes by lipopolysaccharide (LPS-mediated TLR4 activation through an unknown direct or indirect mechanism. Our study demonstrates the utility of network analysis for identification of interesting targets related to innate immune function, and highlights that Ifit1 can exert a positive regulatory effect on downstream genes.

  18. Dynamics of the central bottleneck: dual-task and task uncertainty.

    Directory of Open Access Journals (Sweden)

    Mariano Sigman

    2006-07-01

    Full Text Available Why is the human brain fundamentally limited when attempting to execute two tasks at the same time or in close succession? Two classical paradigms, psychological refractory period (PRP and task switching, have independently approached this issue, making significant advances in our understanding of the architecture of cognition. Yet, there is an apparent contradiction between the conclusions derived from these two paradigms. The PRP paradigm, on the one hand, suggests that the simultaneous execution of two tasks is limited solely by a passive structural bottleneck in which the tasks are executed on a first-come, first-served basis. The task-switching paradigm, on the other hand, argues that switching back and forth between task configurations must be actively controlled by a central executive system (the system controlling voluntary, planned, and flexible action. Here we have explicitly designed an experiment mixing the essential ingredients of both paradigms: task uncertainty and task simultaneity. In addition to a central bottleneck, we obtain evidence for active processes of task setting (planning of the appropriate sequence of actions and task disengaging (suppression of the plan set for the first task in order to proceed with the next one. Our results clarify the chronometric relations between these central components of dual-task processing, and in particular whether they operate serially or in parallel. On this basis, we propose a hierarchical model of cognitive architecture that provides a synthesis of task-switching and PRP paradigms.

  19. The Now-or-Never bottleneck: A fundamental constraint on language.

    Science.gov (United States)

    Christiansen, Morten H; Chater, Nick

    2016-01-01

    Memory is fleeting. New material rapidly obliterates previous material. How, then, can the brain deal successfully with the continual deluge of linguistic input? We argue that, to deal with this "Now-or-Never" bottleneck, the brain must compress and recode linguistic input as rapidly as possible. This observation has strong implications for the nature of language processing: (1) the language system must "eagerly" recode and compress linguistic input; (2) as the bottleneck recurs at each new representational level, the language system must build a multilevel linguistic representation; and (3) the language system must deploy all available information predictively to ensure that local linguistic ambiguities are dealt with "Right-First-Time"; once the original input is lost, there is no way for the language system to recover. This is "Chunk-and-Pass" processing. Similarly, language learning must also occur in the here and now, which implies that language acquisition is learning to process, rather than inducing, a grammar. Moreover, this perspective provides a cognitive foundation for grammaticalization and other aspects of language change. Chunk-and-Pass processing also helps explain a variety of core properties of language, including its multilevel representational structure and duality of patterning. This approach promises to create a direct relationship between psycholinguistics and linguistic theory. More generally, we outline a framework within which to integrate often disconnected inquiries into language processing, language acquisition, and language change and evolution.

  20. Genetic diversity of native Turkish cattle breeds: Mantel, AMOVA and bottleneck analysis

    Directory of Open Access Journals (Sweden)

    Yusuf Özşensoy

    2014-09-01

    Full Text Available This study was conducted to evaluate potential extinction risk of Turkish native cattle breeds using Mantel and AMOVA tests and Bottleneck analysis. A total of 271 DNA samples were isolated from Anatolian Black, Anatolian Grey, South Anatolian Red, Native Southern Anatolian Yellow, East Anatolian Red, and Zavot cattle. In this study, genotypes of 20 microsatellites were determined by capillary electrophoresis and fragment analysis. A total of 269 different alleles were detected. The maximum and minimum numbers of total alleles were observed in TGLA122 (n=26 and INRA005 (n=7 loci, respectively. The highest average observed and expected heterozygosity values were determined as 0.619–0.852 and 0.669–0.877, respectively. The average FIS value was 0.068. Results of AMOVA and Mantel tests illustrated statistically significant differences in populations (p<0.001 and correlation (p<0.01. Bottleneck analysis revealed a normal distribution of L–shaped curve indicating that there was no recent risk of extinction for these breeds.

  1. Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

    Energy Technology Data Exchange (ETDEWEB)

    Nehm, F., E-mail: frederik.nehm@iapp.de; Müller-Meskamp, L.; Klumbies, H.; Leo, K. [Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr-Straße 1, 01069 Dresden (Germany)

    2015-12-15

    A major failure mechanism is identified in electrical calcium corrosion tests for quality assessment of high-end application moisture barriers. Accelerated calcium corrosion is found at the calcium/electrode junction, leading to an electrical bottleneck. This causes test failure not related to overall calcium loss. The likely cause is a difference in electrochemical potential between the aluminum electrodes and the calcium sensor, resulting in a corrosion element. As a solution, a thin, full-area copper layer is introduced below the calcium, shifting the corrosion element to the calcium/copper junction and inhibiting bottleneck degradation. Using the copper layer improves the level of sensitivity for the water vapor transmission rate (WVTR) by over one order of magnitude. Thin-film encapsulated samples with 20 nm of atomic layer deposited alumina barriers this way exhibit WVTRs of 6 × 10{sup −5} g(H{sub 2}O)/m{sup 2}/d at 38 °C, 90% relative humidity.

  2. The physics of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks

    Science.gov (United States)

    Kerner, Boris S.; Koller, Micha; Klenov, Sergey L.; Rehborn, Hubert; Leibel, Michael

    2015-11-01

    Based on an empirical study of real field traffic data measured in 1996-2014 through road detectors installed on German freeways, we reveal physical features of empirical nuclei for spontaneous traffic breakdown in free flow at highway bottlenecks. A microscopic stochastic three-phase traffic model of the nucleation of spontaneous traffic breakdown presented in the article explains the empirical findings. It turns out that in the most cases a nucleus for the breakdown occurs through an interaction of one of waves in free flow with an empirical permanent speed disturbance localized at a highway bottleneck. The wave is a localized structure in free flow, in which the total flow rate is larger and the speed averaged across the highway is smaller than outside the wave. The waves in free flow appear due to oscillations in the percentage of slow vehicles; these waves propagate with the average speed of slow vehicles in free flow. Any of the empirical waves exhibits a two-dimensional asymmetric spatiotemporal structure: Wave's characteristics are different in different highway lanes.

  3. Pedestrian Flow at Bottlenecks - Validation and Calibration of Vissim's Social Force Model of Pedestrian Traffic and its Empirical Foundations

    CERN Document Server

    Kretz, Tobias; Vortisch, Peter

    2008-01-01

    In this contribution first results of experiments on pedestrian flow through bottlenecks are presented and then compared to simulation results obtained with the Social Force Model in the Vissim simulation framework. Concerning the experiments it is argued that the basic dependence between flow and bottleneck width is not a step function but that it is linear and modified by the effect of a psychological phenomenon. The simulation results as well show a linear dependence and the parameters can be calibrated such that the absolute values for flow and time fit to range of experimental results.

  4. Fast electronic relaxation in metal nanoclusters via excitation of coherent shape deformations: Circumventing a bottleneck

    CERN Document Server

    Kresin, V V; Kresin, Vitaly V.; Ovchinnikov, Yu. N.

    2006-01-01

    Electron-phonon relaxation in size-quantized systems may become inhibited when the spacing of discrete electron energy levels exceeds the magnitude of the phonon frequency. We show, however, that nanoclusters can support a fast nonradiative relaxation channel which derives from their distinctive ability to undergo Jahn-Teller shape deformations. Such a deformation represents a collective and coherent vibrational excitation and enables electronic transitions to occur without a multiphonon bottleneck. We analyze this mechanism for a metal cluster within the analytical framework of a three-dimensional potential well undergoing a spheroidal distortion. An expression for the time evolution of the distortion parameter is derived, the electronic level crossing condition formulated, and the probability of electronic transition at a level crossing is evaluated. An application to electron-hole recombination in a closed-shell aluminum cluster with 40 electrons shows that the short (~250 fs) excitation lifetime observed ...

  5. Bottlenecks, burstiness, and fat tails regulate mixing times of non-Poissonian random walks

    CERN Document Server

    Delvenne, Jean-Charles; Rocha, Luis E C

    2013-01-01

    We focus on general continuous-time random walks on networks and find that the mixing time, i.e. the relaxation time for the random process to reach stationarity, is determined by a combination of three factors: the spectral gap, associated to bottlenecks in the underlying topology, burstiness, related to the second moment of the waiting time distribution, and the characteristic time of its exponential tail, which is an indicator of the tail `fatness'. We show theoretically that a strong modular structure dampens the importance of burstiness, and empirically that either of the three factors may be dominant in real-life data. These results provide a theoretical framework for the modeling of diffusion on temporal networks representing human interactions, often characterized by non-Poissonian contact patterns.

  6. Phonon bottleneck in p-type Ge/Si quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Yakimov, A. I., E-mail: yakimov@isp.nsc.ru [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk (Russian Federation); Tomsk State University, 634050 Tomsk (Russian Federation); Kirienko, V. V.; Armbrister, V. A. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk (Russian Federation); Bloshkin, A. A.; Dvurechenskii, A. V. [Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Science, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2015-11-23

    We study the effect of quantum dot size on the mid-infrared photo- and dark current, photoconductive gain, and hole capture probability in ten-period p-type Ge/Si quantum dot heterostructures. The dot dimensions are varied by changing the Ge coverage and the growth temperature during molecular beam epitaxy of Ge/Si(001) system in the Stranski-Krastanov growth mode. In all samples, we observed the general tendency: with decreasing the size of the dots, the dark current and hole capture probability are reduced, while the photoconductive gain and photoresponse are enhanced. Suppression of the hole capture probability in small-sized quantum dots is attributed to a quenched electron-phonon scattering due to phonon bottleneck.

  7. Algorithm Based on Taboo Search and Shifting Bottleneck for Job Shop Scheduling

    Institute of Scientific and Technical Information of China (English)

    Wen-Qi Huang; Zhi Huang

    2004-01-01

    In this paper, a computational effective heuristic method for solving the minimum makespan problem of job shop scheduling is presented. It is based on taboo search procedure and on the shifting bottleneck procedure used to jump out of the trap of the taboo search procedure. A key point of the algorithm is that in the taboo search procedure two taboo lists are used to forbid two kinds of reversals of arcs, which is a new and effective way in taboo search methods for job shop scheduling. Computational experiments on a set of benchmark problem instances show that, in several cases, the approach, in reasonable time, yields better solutions than the other heuristic procedures discussed in the literature.

  8. Head-of-tide bottleneck of particulate material transport from watersheds to estuaries

    Science.gov (United States)

    Ensign, Scott H.; Noe, Gregory; Hupp, Cliff R.; Skalak, Katherine

    2015-01-01

    We measured rates of sediment, C, N, and P accumulation at four floodplain sites spanning the nontidal through oligohaline Choptank and Pocomoke Rivers, Maryland, USA. Ceramic tiles were used to collect sediment for a year and sediment cores were collected to derive decadal sedimentation rates using 137Cs. The results showed highest rates of short- and long-term sediment, C, N, and P accumulation occurred in tidal freshwater forests at the head of tide on the Choptank and the oligohaline marsh of the Pocomoke River, and lowest rates occurred in the downstream tidal freshwater forests in both rivers. Presumably, watershed material was mostly trapped at the head of tide, and estuarine material was trapped in oligohaline marshes. This hydrologic transport bottleneck at the head of tide stores most available watershed sediment, C, N, and P creating a sediment shadow in lower tidal freshwater forests potentially limiting their resilience to sea level rise.

  9. Approximation Algorithm for Bottleneck Steiner Tree Problem in the Euclidean Plane

    Institute of Scientific and Technical Information of China (English)

    Zi-Mao Li; Da-Ming Zhu; Shao-Han Ma

    2004-01-01

    A special case of the bottleneck Steiner tree problem in the Euclidean plane was considered in this paper. The problem has applications in the design of wireless communication networks, multifacility location, VLSI routing and network routing. For the special case which requires that there should be no edge connecting any two Steiner points in the optimal solution, a 3-restricted Steiner tree can be found indicating the existence of the performance ratio √2. In this paper, the special case of the problem is proved to be NP-hard and cannot be approximated within ratio √2. First a simple polynomial time approximation algorithm with performance ratio √3 is presented. Then based on this algorithm and the existence of the 3-restricted Steiner tree, a polynomial time approximation algorithm with performance ratio-√2 + ε is proposed, for any ε>0.

  10. Quality of service estimation based on maximum bottleneck algorithm for domain aggregation in backbone networks

    Institute of Scientific and Technical Information of China (English)

    WANG Yang; ZHAN Yi-chun; YU Shao-hua

    2007-01-01

    This paper investigates the routing among autonomous systems (ASs) with quality of service (QoS) requirements. To avoid the intractability of the problem, abstract QoS capability must be informed among ASs, because the routhing which constrained QoS has been proved to be nondeterministic polynomial-time (NP) hard even inside an AS. This paper employs the modified Dijkstra algorithm to compute the maximum bottleneck bandwidth inside an AS. This approach lays a basis for the AS-level switching capability on which interdomain advertisement can be performed. Furthermore, the paper models the aggregated traffic in backbone network with fractional Brownian motion (FBM), and by integrating along the time axis in short intervals, a good estimation of the distribution of queue length in the next short intervals can be obtained. The proposed advertisement mechanism can be easily implemented with the current interdomain routing protocols. Numerical study indicates that the presented scheme is effective and feasible.

  11. Juvenile bottlenecks and salinity shape grey mullet assemblages in Mediterranean estuaries

    Science.gov (United States)

    Cardona, Luis; Hereu, Bernat; Torras, Xavier

    2008-05-01

    Previous research has suggested that competitive bottlenecks may exist for the Mediterranean grey mullets (Osteichthyes, Mugilidae) at the fry stage with the exotic Cyprinus carpio (Osteichthyes, Cyprinidae) playing a central role. As a consequence, the structure of grey mullet assemblages at later stages is thought to reflect previous competition as well as differences in osmoregulatory skills. This paper tests that hypothesis by examining four predictions about the relative abundance of five grey mullet species in 42 Western Mediterranean estuary sites from three areas (Aiguamolls de l'Empordà, Ebro Delta and Minorca) differing in the salinity level and occurrence of C. carpio. Field data confirmed the predictions as: (1) Liza aurata and Mugil cephalus were scarce everywhere and never dominated the assemblage; (2) Liza saliens dominated the assemblage where the salinity level was higher than 13; (3) Liza ramado always dominated the assemblage where the salinity level was lower than 13 and C. carpio was present; and (4) Chelon labrosus dominated the assemblage only where the salinity level was lower than 13 and C. carpio was absent. The catch per unit effort of C. labrosus of any size was smaller in the presence of C. carpio than where it had not been introduced, which is in agreement with the juvenile competitive bottleneck hypothesis. Discriminant analysis confirmed that the assemblage structure was linked to the salinity level and the occurrence of C. carpio for both early juveniles and late juveniles as well as adults. The data reported here reveal that the structure of grey mullet assemblages inhabiting Mediterranean estuaries is determined by salinity and competitive interactions at the fry stage.

  12. Fixation times in differentiation and evolution in the presence of bottlenecks, deserts, and oases.

    Science.gov (United States)

    Chou, Tom; Wang, Yu

    2015-05-01

    Cellular differentiation and evolution are stochastic processes that can involve multiple types (or states) of particles moving on a complex, high-dimensional state-space or "fitness" landscape. Cells of each specific type can thus be quantified by their population at a corresponding node within a network of states. Their dynamics across the state-space network involve genotypic or phenotypic transitions that can occur upon cell division, such as during symmetric or asymmetric cell differentiation, or upon spontaneous mutation. Here, we use a general multi-type branching processes to study first passage time statistics for a single cell to appear in a specific state. Our approach readily allows for nonexponentially distributed waiting times between transitions, reflecting, e.g., the cell cycle. For simplicity, we restrict most of our detailed analysis to exponentially distributed waiting times (Poisson processes). We present results for a sequential evolutionary process in which L successive transitions propel a population from a "wild-type" state to a given "terminally differentiated," "resistant," or "cancerous" state. Analytic and numeric results are also found for first passage times across an evolutionary chain containing a node with increased death or proliferation rate, representing a desert/bottleneck or an oasis. Processes involving cell proliferation are shown to be "nonlinear" (even though mean-field equations for the expected particle numbers are linear) resulting in first passage time statistics that depend on the position of the bottleneck or oasis. Our results highlight the sensitivity of stochastic measures to cell division fate and quantify the limitations of using certain approximations (such as the fixed-population and mean-field assumptions) in evaluating fixation times.

  13. Reducing the Disk IO Bandwidth Bottleneck through Fast Floating Point Compression using Accelerators

    Directory of Open Access Journals (Sweden)

    Ajith Padyana

    2014-03-01

    Full Text Available Compute-intensive tasks in high-end high performance computing (HPC systems often generate large amounts of data, especially floating-point data that need to be transmitted over the network. Although computation speeds are very high, the overall performance of these applications is affected by the data transfer overhead. Moreover, as data sets are growing in size rapidly, bandwidth limitations pose a serious bottleneck in several scientific applications. Fast floating point compression can ameliorate the bandwidth limitations. If data is compressed well, then the amount of data transfer is reduced. This reduction in data transfer time comes at the expense of the increased computation required by compression and decompression. It is important for compression and decompression rates to be greater than the network bandwidth; otherwise, it will be faster to transmit uncompressed data directly [1]. Accelerators such as Graphics Processing Units (GPU provide much computational power. In this paper, we show that the computational power of GPUs and CellBE processor can be harnessed to provide sufficiently fast compression and decompression for this approach to be effective for data produced by many practical applications. In particularly, we use Holt`s Exponential smoothing algorithm from time series analysis, and encode the difference between its predictions and the actual data. This yields a lossless compression scheme. We show that it can be implemented efficiently on GPUs and CellBE to provide an effective compression scheme for the purpose of saving on data transfer overheads The primary contribution of this work lies in demonstrating the potential of floating point compression in reducing the I/O bandwidth bottleneck on modern hardware for important classes of scientific applications.

  14. Microsatellite variation and rare alleles in a bottlenecked Hawaiian Islands endemic: implications for reintroductions

    Science.gov (United States)

    Reynolds, Michelle H.; Pearce, John M.; Lavretsky, Philip; Seixas, Pedro P.; Courtot, Karen

    2015-01-01

    Conservation of genetic biodiversity in endangered wildlife populations is an important challenge to address since the loss of alleles and genetic drift may influence future adaptability. Reintroduction aims to re-establish species to restored or protected ecosystems; however, moving a subset of individuals may result in loss of gene variants during the management-induced bottleneck (i.e. translocation). The endangered Laysan teal Anas laysanensis was once widespread across the Hawaiian archipelago, but became isolated on Laysan Island (415 ha) from the mid-1800s until 2004 when a translocation to Midway Atoll (596 ha) was undertaken to reduce extinction risks. We compared genetic diversity and quantified variation at microsatellite loci sampled from 230 individuals from the wild populations at Laysan (1999 to 2009) and Midway (2007 to 2010; n = 133 Laysan, n = 96 Midway birds). We identified polymorphic markers by screening nuclear microsatellites (N = 83). Low nuclear variation was detected, consistent with the species’ insular isolation and historical bottleneck. Six of 83 microsatellites were polymorphic. We found limited but similar estimates of allelic richness (2.58 alleles per locus) and heterozygosity within populations. However, 2 rare alleles found in the Laysan source population were not present in Midway’s reintroduced population, and a unique allele was discovered in an individual on Midway. Differentiation between island populations was low (FST = 0.6%), but statistically significant. Our results indicate that genetic drift had little effect on offspring generations 3 to 6 yr post-release and demonstrate the utility of using known founder events to help quantify genetic capture during translocations and to inform management decisions.

  15. 一种城市交通瓶颈的计算方法%Method for calculating urban traffic bottlenecks

    Institute of Scientific and Technical Information of China (English)

    邱淳风; 温晓岳; 靳明豪; 李建元

    2015-01-01

    城市交通瓶颈指的是常发性拥堵路段或位置。以往基于交警的巡查经验来确定交通瓶颈,虽可以部分地反映实际情况,但成本太高且无法做到动态跟踪。运用交通传感数据提出了一个简单的交通瓶颈计算方法,通过计算统计周期内的路段拥堵概率来反映交通瓶颈的严重程度。实验表明该方法是有效的。%Traffic bottlenecks refer to road segments or locations with frequent traffic jams. Traditional methods for evaluating traffic bottlenecks are mainly based on patrol experience, which could partly work but is costly and cannot dynamically track the change of bottlenecks. This paper proposed a simple method that evaluates bottlenecks by using the congestion probabilities of road segments obtained from the analysis of traffic sensing data. The experimental results show the effectiveness of the proposed method.

  16. Capacity drop: A comparison between stop-and-go wave and standing queue at lane-drop bottleneck

    NARCIS (Netherlands)

    Yuan, K.; Knoop, V.L.; Leclercq, L.; Hoogendoorn, S.P.

    2014-01-01

    In freeways, the maximum traffic flow through a bottleneck is usually higher than the outflow of congestion there. This phenomenon is called the capacity drop. In literature, there are considerable debates about the mechanism causing this phenomenon. This paper studies the mechanism by analyzing rea

  17. A decomposition heuristics based on multi-bottleneck machines for large-scale job shop scheduling problems

    Directory of Open Access Journals (Sweden)

    Yingni Zhai

    2014-10-01

    Full Text Available Purpose: A decomposition heuristics based on multi-bottleneck machines for large-scale job shop scheduling problems (JSP is proposed.Design/methodology/approach: In the algorithm, a number of sub-problems are constructed by iteratively decomposing the large-scale JSP according to the process route of each job. And then the solution of the large-scale JSP can be obtained by iteratively solving the sub-problems. In order to improve the sub-problems' solving efficiency and the solution quality, a detection method for multi-bottleneck machines based on critical path is proposed. Therewith the unscheduled operations can be decomposed into bottleneck operations and non-bottleneck operations. According to the principle of “Bottleneck leads the performance of the whole manufacturing system” in TOC (Theory Of Constraints, the bottleneck operations are scheduled by genetic algorithm for high solution quality, and the non-bottleneck operations are scheduled by dispatching rules for the improvement of the solving efficiency.Findings: In the process of the sub-problems' construction, partial operations in the previous scheduled sub-problem are divided into the successive sub-problem for re-optimization. This strategy can improve the solution quality of the algorithm. In the process of solving the sub-problems, the strategy that evaluating the chromosome's fitness by predicting the global scheduling objective value can improve the solution quality.Research limitations/implications: In this research, there are some assumptions which reduce the complexity of the large-scale scheduling problem. They are as follows: The processing route of each job is predetermined, and the processing time of each operation is fixed. There is no machine breakdown, and no preemption of the operations is allowed. The assumptions should be considered if the algorithm is used in the actual job shop.Originality/value: The research provides an efficient scheduling method for the

  18. Population structure and genetic bottleneck in sweet cherry estimated with SSRs and the gametophytic self-incompatibility locus

    Directory of Open Access Journals (Sweden)

    Mariette Stéphanie

    2010-08-01

    Full Text Available Abstract Background Domestication and breeding involve the selection of particular phenotypes, limiting the genomic diversity of the population and creating a bottleneck. These effects can be precisely estimated when the location of domestication is established. Few analyses have focused on understanding the genetic consequences of domestication and breeding in fruit trees. In this study, we aimed to analyse genetic structure and changes in the diversity in sweet cherry Prunus avium L. Results Three subgroups were detected in sweet cherry, with one group of landraces genetically very close to the analysed wild cherry population. A limited number of SSR markers displayed deviations from the frequencies expected under neutrality. After the removal of these markers from the analysis, a very limited bottleneck was detected between wild cherries and sweet cherry landraces, with a much more pronounced bottleneck between sweet cherry landraces and modern sweet cherry varieties. The loss of diversity between wild cherries and sweet cherry landraces at the S-locus was more significant than that for microsatellites. Particularly high levels of differentiation were observed for some S-alleles. Conclusions Several domestication events may have happened in sweet cherry or/and intense gene flow from local wild cherry was probably maintained along the evolutionary history of the species. A marked bottleneck due to breeding was detected, with all markers, in the modern sweet cherry gene pool. The microsatellites did not detect the bottleneck due to domestication in the analysed sample. The vegetative propagation specific to some fruit trees may account for the differences in diversity observed at the S-locus. Our study provides insights into domestication events of cherry, however, requires confirmation on a larger sampling scheme for both sweet cherry landraces and wild cherry.

  19. A single origin and moderate bottleneck during domestication of soybean (Glycine max): implications from microsatellites and nucleotide sequences.

    Science.gov (United States)

    Guo, Juan; Wang, Yunsheng; Song, Chi; Zhou, Jianfeng; Qiu, Lijuan; Huang, Hongwen; Wang, Ying

    2010-09-01

    Background and Aims It is essential to illuminate the evolutionary history of crop domestication in order to understand further the origin and development of modern cultivation and agronomy; however, despite being one of the most important crops, the domestication origin and bottleneck of soybean (Glycine max) are poorly understood. In the present study, microsatellites and nucleotide sequences were employed to elucidate the domestication genetics of soybean. Methods The genomes of 79 landrace soybeans (endemic cultivated soybeans) and 231 wild soybeans (G. soja) that represented the species-wide distribution of wild soybean in East Asia were scanned with 56 microsatellites to identify the genetic structure and domestication origin of soybean. To understand better the domestication bottleneck, four nucleotide sequences were selected to simulate the domestication bottleneck. Key Results Model-based analysis revealed that most of the landrace genotypes were assigned to the inferred wild soybean cluster of south China, South Korea and Japan. Phylogeny for wild and landrace soybeans showed that all landrace soybeans formed a single cluster supporting a monophyletic origin of all the cultivars. The populations of the nearest branches which were basal to the cultivar lineage were wild soybeans from south China. The coalescent simulation detected a bottleneck severity of K' = 2 during soybean domestication, which could be explained by a foundation population of 6000 individuals if domestication duration lasted 3000 years. Conclusions As a result of integrating geographic distribution with microsatellite genotype assignment and phylogeny between landrace and wild soybeans, a single origin of soybean in south China is proposed. The coalescent simulation revealed a moderate genetic bottleneck with an effective wild soybean population used for domestication estimated to be approximately 2 % of the total number of ancestral wild soybeans. Wild soybeans in Asia, especially in

  20. Genetic architecture and bottleneck analyses of Salem Black goat breed based on microsatellite markers

    Directory of Open Access Journals (Sweden)

    A. K. Thiruvenkadan

    2014-09-01

    Full Text Available Aim: The present study was undertaken in Salem Black goat population for genetic analysis at molecular level to exploit the breed for planning sustainable improvement, conservation and utilization, which subsequently can improve the livelihood of its stakeholders. Materials and Methods: Genomic DNA was isolated from blood samples of 50 unrelated Salem Black goats with typical phenotypic features in several villages in the breeding tract and the genetic characterization and bottleneck analysis in Salem Black goat was done using 25 microsatellite markers as recommended by the Food and Agricultural Organization, Rome, Italy. The basic measures of genetic variation were computed using bioinformatic software. To evaluate the Salem Black goats for mutation drift equilibrium, three tests were performed under three different mutation models, viz., infinite allele model (IAM, stepwise mutation model (SMM and two-phase model (TPM and the observed gene diversity (He and expected equilibrium gene diversity (Heq were estimated under different models of microsatellite evolution. Results: The study revealed that the observed number of alleles ranged from 4 (ETH10, ILSTS008 to 17 (BM64444 with a total of 213 alleles and mean of 10.14±0.83 alleles across loci. The overall observed heterozygosity, expected heterozygosity, inbreeding estimate and polymorphism information content values were 0.631±0.041, 0.820±0.024, 0.233±0.044 and 0.786±0.023 respectively indicating high genetic diversity. The average observed gene diversities (He pooled over different markers was 0.829±0.024 and the average expected gene diversities under IAM, TPM and SMM models were 0.769±0.026, 0.808±0.024 and 0.837±0.020 respectively. The number of loci found to exhibit gene diversity excess under IAM, TPM and SMM models were 18, 17 and 12 respectively. Conclusion: All the three statistical tests, viz., sign test, standardized differences test and Wilcoxon sign rank test, revealed

  1. Effect of density feedback on the two-route traffic scenario with bottleneck

    Science.gov (United States)

    Sun, Xiao-Yan; Ding, Zhong-Jun; Huang, Guo-Hua

    2016-12-01

    In this paper, we investigate the effect of density feedback on the two-route scenario with a bottleneck. The simulation and theory analysis shows that there exist two critical vehicle entry probabilities αc1 and αc2. When vehicle entry probability α≤αc1, four different states, i.e. free flow state, transition state, maximum current state and congestion state are identified in the system, which correspond to three critical reference densities. However, in the interval αc1congestion state when α≥αc2. According to the results, traffic control center can adjust the reference density so that the system is in maximum current state. In this case, the capacity of the traffic system reaches maximum so that drivers can make full use of the roads. We hope that the study results can provide good advice for alleviating traffic jam and be useful to traffic control center for designing advanced traveller information systems.

  2. Metabolic Engineering of Yeast to Produce Fatty Acid-derived Biofuels: Bottlenecks and Solutions

    Directory of Open Access Journals (Sweden)

    Jiayuan eSheng

    2015-06-01

    Full Text Available Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles.

  3. Breaking the carrier injection bottleneck of phosphor-free nanowire white light-emitting diodes.

    Science.gov (United States)

    Nguyen, Hieu Pham Trung; Zhang, Shaofei; Connie, Ashfiqua T; Kibria, Md Golam; Wang, Qi; Shih, Ishiang; Mi, Zetian

    2013-01-01

    We have examined the carrier injection process of axial nanowire light-emitting diode (LED) structures and identified that poor carrier injection efficiency, due to the large surface recombination, is the primary cause for the extremely low output power of phosphor-free nanowire white LEDs. We have further developed InGaN/GaN/AlGaN dot-in-a-wire core-shell white LEDs on Si substrate, which can break the carrier injection efficiency bottleneck, leading to a massive enhancement in the output power. At room temperature, the devices can exhibit an output power of ~1.5 mW, which is more than 2 orders of magnitude stronger than nanowire LEDs without shell coverage. Additionally, such phosphor-free nanowire white LEDs can deliver an unprecedentedly high color rendering index of ~92-98 in both the warm and cool white regions, with the color rendering capability approaching that of an ideal light source, i.e. a blackbody.

  4. Identifying Processor Bottlenecks in Virtual Machine Based Execution of Java Bytecode

    Science.gov (United States)

    Rao, Pradeep; Murakami, Kazuaki

    Despite the prevalence of Java workloads across a variety of processor architectures, there is very little published data on the impact of the various processor design decisions on Java performance. We attribute the lack of data to the large design space resulting from the complexity of the modern superscalar processor and the additional complexities associated with executing Java bytecode using a virtual machine. To address this shortcoming, we use a statistically rigorous methodology to systematically quantify the the impact of the various processor microarchitecture parameters on Java execution performance. The adopted methodology enables efficient screening of significant factor effects in a large design space consisting of 35 factors (32-billion potential configurations) using merely 72 observations per benchmark application. We quantify and tabulate the significance of each of the 35 factors for 13 benchmark applications. While these tables provide various insights into Java performance, they consistently highlight the performance significance of the instruction delivery mechanism, especially the instruction cache and the ITLB design parameters. Furthermore, these tables enable the architect to identify processor bottlenecks for Java workloads by providing an estimate of the relative impact of various design decisions.

  5. Calculation of the mean circle size does not circumvent the bottleneck of crowding.

    Science.gov (United States)

    Banno, Hayaki; Saiki, Jun

    2012-10-22

    Visually, we can extract a statistical summary of sets of elements efficiently. However, our visual system has a severe limitation in that the ability to recognize an object is remarkably impaired when it is surrounded by other objects. The goal of this study was to investigate whether the crowding effect obstructs the calculation of the mean size of objects. First, we verified that the crowding effect occurs when comparing the sizes of circles (Experiment 1). Next, we manipulated the distances between circles and measured the sensitivity when circles were on or off the limitation of crowding (Experiment 2). Participants were asked to compare the mean sizes of the circles in the left and right visual fields and to judge which was larger. Participants' sensitivity to mean size difference was lower when the circles were located in the nearer distance. Finally, we confirmed that crowding is responsible for the observed results by showing that displays without a crowded object eliminated the effects (Experiment 3). Our results indicate that the statistical information of size does not circumvent the bottleneck of crowding.

  6. Development and bottlenecks of renewable electricity generation in China: a critical review.

    Science.gov (United States)

    Hu, Yuanan; Cheng, Hefa

    2013-04-02

    This review provides an overview on the development and status of electricity generation from renewable energy sources, namely hydropower, wind power, solar power, biomass energy, and geothermal energy, and discusses the technology, policy, and finance bottlenecks limiting growth of the renewable energy industry in China. Renewable energy, dominated by hydropower, currently accounts for more than 25% of the total electricity generation capacity. China is the world's largest generator of both hydropower and wind power, and also the largest manufacturer and exporter of photovoltaic cells. Electricity production from solar and biomass energy is at the early stages of development in China, while geothermal power generation has received little attention recently. The spatial mismatch in renewable energy supply and electricity demand requires construction of long-distance transmission networks, while the intermittence of renewable energy poses significant technical problems for feeding the generated electricity into the power grid. Besides greater investment in research and technology development, effective policies and financial measures should also be developed and improved to better support the healthy and sustained growth of renewable electricity generation. Meanwhile, attention should be paid to the potential impacts on the local environment from renewable energy development, despite the wider benefits for climate change.

  7. Neutron capture cross section of $^{90}$Zr Bottleneck in the s-process reaction flow

    CERN Document Server

    Tagliente, G; Milazzo, P M; Moreau, C; Aerts, G; Abbondanno, U; Alvarez, H; Alvarez-Velarde, F; Andriamonje, Samuel A; Andrzejewski, J; Assimakopoulos, Panayiotis; Audouin, L; Badurek, G; Baumann, P; Bečvář, F; Berthoumieux, E; Bisterzo, S; Calviño, F; Calviani, M; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillman, I; Domingo-Pardo, C; Dridi, W; Durán, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Furman, W; Gallino, R; Gonçalves, I; Gonzalez-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Köhler, P; Kossionides, E; Krtička, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mastinu, P; Mengoni, A; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Santos, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M, C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2008-01-01

    The neutron capture cross sections of the Zr isotopes have important implications in nuclear astrophysics and for reactor design. The small cross section of the neutron magic nucleus 90Zr, which accounts for more than 50% of natural zirconium represents one of the key isotopes for the stellar s-process, because it acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier isotopes. The same element, Zr, also is an important component of the structural materials used in traditional and advanced nuclear reactors. The (n,γ) cross section has been measured at CERN, using the n_TOF spallation neutron source. In total, 45 resonances could be resolved in the neutron energy range below 70 keV, 10 being observed for the first time thanks to the high resolution and low backgrounds at n_TOF. On average, the Γγ widths obtained in resonance analyses with the R-matrix code SAMMY were 15% smaller than reported previously. By these results, the accuracy of the Maxwellian averaged cross section f...

  8. Distinguishing between population bottleneck and population subdivision by a Bayesian model choice procedure.

    Science.gov (United States)

    Peter, Benjamin M; Wegmann, Daniel; Excoffier, Laurent

    2010-11-01

    Although most natural populations are genetically subdivided, they are often analysed as if they were panmictic units. In particular, signals of past demographic size changes are often inferred from genetic data by assuming that the analysed sample is drawn from a population without any internal subdivision. However, it has been shown that a bottleneck signal can result from the presence of some recent immigrants in a population. It thus appears important to contrast these two alternative scenarios in a model choice procedure to prevent wrong conclusions to be made. We use here an Approximate Bayesian Computation (ABC) approach to infer whether observed patterns of genetic diversity in a given sample are more compatible with it being drawn from a panmictic population having gone through some size change, or from one or several demes belonging to a recent finite island model. Simulations show that we can correctly identify samples drawn from a subdivided population in up to 95% of the cases for a wide range of parameters. We apply our model choice procedure to the case of the chimpanzee (Pan troglodytes) and find conclusive evidence that Western and Eastern chimpanzee samples are drawn from a spatially subdivided population.

  9. Only adding stationary storage to vaccine supply chains may create and worsen transport bottlenecks.

    Science.gov (United States)

    Haidari, Leila A; Connor, Diana L; Wateska, Angela R; Brown, Shawn T; Mueller, Leslie E; Norman, Bryan A; Schmitz, Michelle M; Paul, Proma; Rajgopal, Jayant; Welling, Joel S; Leonard, Jim; Claypool, Erin G; Weng, Yu-Ting; Chen, Sheng-I; Lee, Bruce Y

    2013-01-01

    Although vaccine supply chains in many countries require additional stationary storage and transport capacity to meet current and future needs, international donors tend to donate stationary storage devices far more often than transport equipment. To investigate the impact of only adding stationary storage equipment on the capacity requirements of transport devices and vehicles, we used HERMES (Highly Extensible Resource for Modeling Supply Chains) to construct a discrete event simulation model of the Niger vaccine supply chain. We measured the transport capacity requirement for each mode of transport used in the Niger vaccine cold chain, both before and after adding cold rooms and refrigerators to relieve all stationary storage constraints in the system. With the addition of necessary stationary storage, the average transport capacity requirement increased from 88% to 144% for cold trucks, from 101% to 197% for pickup trucks, and from 366% to 420% for vaccine carriers. Therefore, adding stationary storage alone may worsen or create new transport bottlenecks as more vaccines flow through the system, preventing many vaccines from reaching their target populations. Dynamic modeling can reveal such relationships between stationary storage capacity and transport constraints.

  10. Surviving in isolation: genetic variation, bottlenecks and reproductive strategies in the Canarian endemic Limonium macrophyllum (Plumbaginaceae).

    Science.gov (United States)

    Jiménez, Ares; Weigelt, Barbara; Santos-Guerra, Arnoldo; Caujapé-Castells, Juli; Fernández-Palacios, José María; Conti, Elena

    2017-02-01

    Oceanic archipelagos are typically rich in endemic taxa, because they offer ideal conditions for diversification and speciation in isolation. One of the most remarkable evolutionary radiations on the Canary Islands comprises the 16 species included in Limonium subsection Nobiles, all of which are subject to diverse threats, and legally protected. Since many of them are single-island endemics limited to one or a few populations, there exists a risk that a loss of genetic variation might limit their long-term survival. In this study, we used eight newly developed microsatellite markers to characterize the levels of genetic variation and inbreeding in L. macrophyllum, a species endemic to the North-east of Tenerife that belongs to Limonium subsection Nobiles. We detected generally low levels of genetic variation over all populations (H T = 0.363), and substantial differentiation among populations (F ST = 0.188; R ST = 0.186) coupled with a negligible degree of inbreeding (F = 0.042). Obligate outcrossing may have maintained L. macrophyllum relatively unaffected by inbreeding despite the species' limited dispersal ability and the genetic bottlenecks likely caused by a prolonged history of grazing. Although several factors still constitute a risk for the conservation of L. macrophyllum, the lack of inbreeding and the recent positive demographic trends observed in the populations of this species are factors that favour its future persistence.

  11. Independent bottlenecks characterize colonization of systemic compartments and gut lymphoid tissue by salmonella.

    Directory of Open Access Journals (Sweden)

    Chee Han Lim

    2014-07-01

    Full Text Available Vaccination represents an important instrument to control typhoid fever in humans and protects mice from lethal infection with mouse pathogenic serovars of Salmonella species. Mixed infections with tagged Salmonella can be used in combination with probabilistic models to describe the dynamics of the infection process. Here we used mixed oral infections with tagged Salmonella strains to identify bottlenecks in the infection process in naïve and vaccinated mice. We established a next generation sequencing based method to characterize the composition of tagged Salmonella strains which offers a fast and reliable method to characterise the composition of genome-tagged Salmonella strains. We show that initial colonization of Salmonella was distinguished by a non-Darwinian selection of few bacteria setting up the infection independently in gut associated lymphoid tissue and systemic compartments. Colonization of Peyer's patches fuels the sustained spread of bacteria into mesenteric lymph nodes via dendritic cells. In contrast, infection of liver and spleen originated from an independent pool of bacteria. Vaccination only moderately reduced invasion of Peyer's patches but potently uncoupled bacterial populations present in different systemic compartments. Our data indicate that vaccination differentially skews the capacity of Salmonella to colonize systemic and gut immune compartments and provide a framework for the further dissection of infection dynamics.

  12. Independent bottlenecks characterize colonization of systemic compartments and gut lymphoid tissue by salmonella.

    Science.gov (United States)

    Lim, Chee Han; Voedisch, Sabrina; Wahl, Benjamin; Rouf, Syed Fazle; Geffers, Robert; Rhen, Mikael; Pabst, Oliver

    2014-07-01

    Vaccination represents an important instrument to control typhoid fever in humans and protects mice from lethal infection with mouse pathogenic serovars of Salmonella species. Mixed infections with tagged Salmonella can be used in combination with probabilistic models to describe the dynamics of the infection process. Here we used mixed oral infections with tagged Salmonella strains to identify bottlenecks in the infection process in naïve and vaccinated mice. We established a next generation sequencing based method to characterize the composition of tagged Salmonella strains which offers a fast and reliable method to characterise the composition of genome-tagged Salmonella strains. We show that initial colonization of Salmonella was distinguished by a non-Darwinian selection of few bacteria setting up the infection independently in gut associated lymphoid tissue and systemic compartments. Colonization of Peyer's patches fuels the sustained spread of bacteria into mesenteric lymph nodes via dendritic cells. In contrast, infection of liver and spleen originated from an independent pool of bacteria. Vaccination only moderately reduced invasion of Peyer's patches but potently uncoupled bacterial populations present in different systemic compartments. Our data indicate that vaccination differentially skews the capacity of Salmonella to colonize systemic and gut immune compartments and provide a framework for the further dissection of infection dynamics.

  13. Circum-planetary discs as bottlenecks for gas accretion onto giant planets

    CERN Document Server

    Rivier, Guillaume; Morbidelli, Alessandro; Brouet, Yann

    2012-01-01

    With hundreds of exoplanets detected, it is necessary to revisit giant planets accretion models to explain their mass distribution. In particular, formation of sub-jovian planets remains unclear, given the short timescale for the runaway accretion of massive atmospheres. However, gas needs to pass through a circum-planetary disc. If the latter has a low viscosity (as expected if planets form in "dead zones"), it might act as a bottleneck for gas accretion. We investigate what the minimum accretion rate is for a planet under the limit assumption that the circum-planetary disc is totally inviscid, and the transport of angular momentum occurs solely because of the gravitational perturbations from the star. To estimate the accretion rate, we present a steady-state model of an inviscid circum-planetary disc, with vertical gas inflow and external torque from the star. Hydrodynamical simulations of a circum-planetary disc were conducted in 2D, in a planetocentric frame, with the star as an external perturber in orde...

  14. Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Méndez, M Soledad; Ballaré, Carlos L

    2016-04-19

    A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.

  15. Pressure-temperature dependence of growth bottlenecks and phenotypic transitions of Escherichia coli

    Science.gov (United States)

    Kumar, Pradeep; Libchaber, Albert J.

    2012-02-01

    A vast majority of bacteria and archaea can grow in diverse environmental conditions. The range of those conditions include high pressures, high temperature, low temperature, high salinity, low and high pH etc. We investigate the growth bottlenecks and phenotypic transitions of Escherichia coli (E. coli), a mesophilic bacterium, as a function of pressure and temperature. We find that E.coli can grow and proliferate in a wide range of pressures (1-400 atm) and temperatures (23-40 deg C). Moreover, we find that the division time of E. coli increases monotonically upon increasing pressure and exhibits a sharp increase in division time at pressures between 250-400 atm for all the temperatures investigated in our experiments. The sharp change in division time is followed by a sharp change in phenotypic transition of E. Coli at high pressures where bacterial cells switch to an elongating cell type. We propose that this phenotypics changes in bacteria at high pressures is an irreversible stochastic process whereas the switching probability to elongating cell type increases with increasing pressure. Furthermore, we propose an irreversible stochastic model of cell phenotype switching. We find that model fits well the experimental data. We discuss our experimental results in the light of structural and so the functional changes in proteins and structural changes in membranes at different pressure and temperature.

  16. 城市轨道交通车站动态瓶颈识别方法研究%Identification of Dynamic Bottlenecks of Urban Rail Transit Stations

    Institute of Scientific and Technical Information of China (English)

    黄令海; 李海鹰; 许心越

    2015-01-01

    瓶颈识别是城市轨道交通车站规划设计和运营管理亟待解决的难题。本文在既有静态瓶颈和动态瓶颈的基础上,按动态瓶颈产生原因将其细化为原发性瓶颈及继发性瓶颈;研究瓶颈的动态传播特性,提出关联瓶颈与瓶颈簇理论,以此刻画瓶颈传播机理,并在此基础上构建车站动态瓶颈识别方法;以瓶颈簇理论为支撑,定量分析单个设备能力对车站集散能力的影响程度,提出基于灵敏度分析的瓶颈疏解策略。最后,对北京地铁某车站进行案例分析,验证该瓶颈识别方法的有效性与实用性。案例表明,该方法能够有效识别车站瓶颈,明确瓶颈之间的依附关系以及瓶颈的重要程度。与既有方法相比减少66.7%的仿真次数,可以明显提高识别效率。%Bottleneck identification is an urgent issue that needs to be addressed in the planning,design and op-eration management of urban rail transit stations.Based on the concepts of existing static bottlenecks and dy-namic bottlenecks,dynamic bottlenecks were classified into two categories,i.e.primary bottlenecks and sec-ondary bottlenecks,according to the causes of dynamic bottlenecks.The dynamic bottleneck transmission characteristics were studied,and the correlation bottleneck and bottleneck cluster concepts were proposed to describe the bottleneck transmission mechanism,whereby a new bottleneck identification method was pro-posed.Supported by bottleneck cluster concept,quantitative analysis was conducted on the effect of the capaci-ty of an individual facility on collection and distribution capacity of the station,and sensitivity analysis-based bottleneck relief strategy was proposed.Finally,a case study of a station in Beijing subway was implemented to verify the validity and practicability of the proposed method.The results showed that this method can identi-fy the bottlenecks of a station effectively,and define the dependence

  17. Are all intertidal wetlands naturally created equal? Bottlenecks, thresholds and knowledge gaps to mangrove and saltmarsh ecosystems

    Science.gov (United States)

    Friess, Daniel A.; Krauss, Ken W.; Horstman, Erik M.; Balke, Thorsten; Bouma, Tjeerd J.; Galli, Demis; Webb, Edward L.

    2011-01-01

    Intertidal wetlands such as saltmarshes and mangroves provide numerous important ecological functions, though they are in rapid and global decline. To better conserve and restore these wetland ecosystems, we need an understanding of the fundamental natural bottlenecks and thresholds to their establishment and long-term ecological maintenance. Despite inhabiting similar intertidal positions, the biological traits of these systems differ markedly in structure, phenology, life history, phylogeny and dispersal, suggesting large differences in biophysical interactions. By providing the first systematic comparison between saltmarshes and mangroves, we unravel how the interplay between species-specific life-history traits, biophysical interactions and biogeomorphological feedback processes determine where, when and what wetland can establish, the thresholds to long-term ecosystem stability, and constraints to genetic connectivity between intertidal wetland populations at the landscape level. To understand these process interactions, research into the constraints to wetland development, and biological adaptations to overcome these critical bottlenecks and thresholds requires a truly interdisciplinary approach.

  18. Addressing the current bottlenecks of metabolomics: Isotopic Ratio Outlier Analysis™, an isotopic-labeling technique for accurate biochemical profiling.

    Science.gov (United States)

    de Jong, Felice A; Beecher, Chris

    2012-09-01

    Metabolomics or biochemical profiling is a fast emerging science; however, there are still many associated bottlenecks to overcome before measurements will be considered robust. Advances in MS resolution and sensitivity, ultra pressure LC-MS, ESI, and isotopic approaches such as flux analysis and stable-isotope dilution, have made it easier to quantitate biochemicals. The digitization of mass spectrometers has simplified informatic aspects. However, issues of analytical variability, ion suppression and metabolite identification still plague metabolomics investigators. These hurdles need to be overcome for accurate metabolite quantitation not only for in vitro systems, but for complex matrices such as biofluids and tissues, before it is possible to routinely identify biomarkers that are associated with the early prediction and diagnosis of diseases. In this report, we describe a novel isotopic-labeling method that uses the creation of distinct biochemical signatures to eliminate current bottlenecks and enable accurate metabolic profiling.

  19. A New Wireless Packet Scheduling Algorithm Based on EDF and Its Application in Multi-bottleneck Networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Most of current wireless packet scheduling algorithms aim at resource allocation as fairly as possible or maximizing throughput. This paper proposed a new packet scheduling algorithm that aims at satisfying delay requirement and is the improvement of earliest due first (EDF) algorithm in wired networks. The main idea is to classify the packets based on their delay bound, scheduling the most "urgent" class of user and the users that have the best channel condition with higher priority. This algorithm can easily integrate with common buffer management algorithms, when buffer management algorithm cannot accept new arrival packets, try to modify scheduling policy. Packet scheduling algorithms in multiple bottleneck wireless networks were also discussed. A new variable multi-hop factor was defined to estimate the congestion situation (including channel condition) of future hops.Multi-hop factor can be integrated into packet scheduling algorithms as assistant and supplement to improve its performance in multi-bottleneck wireless networks.

  20. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus

    Science.gov (United States)

    Tully, Damien C.; Ogilvie, Colin B.; Batorsky, Rebecca E.; Bean, David J.; Power, Karen A.; Ghebremichael, Musie; Bedard, Hunter E.; Gladden, Adrianne D.; Seese, Aaron M.; Amero, Molly A.; Lane, Kimberly; McGrath, Graham; Bazner, Suzane B.; Tinsley, Jake; Lennon, Niall J.; Henn, Matthew R.; Brumme, Zabrina L.; Norris, Philip J.; Rosenberg, Eric S.; Mayer, Kenneth H.; Jessen, Heiko; Kosakovsky Pond, Sergei L.; Walker, Bruce D.; Altfeld, Marcus; Carlson, Jonathan M.; Allen, Todd M.

    2016-01-01

    Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM) exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX) transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU), we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic “signatures” within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission. PMID:27163788

  1. Identification of Bottlenecks and Capacity Constraints in F-14, F-15, F-16, and F/A-18 Aircraft Production.

    Science.gov (United States)

    1983-04-01

    TRENDS IN LEAD TIME One important indication of the existence of capaci+ constraints and bottlenecks is the amount of lead cime required to obtain an item...MAK11BUY PRODUCTIONi AV11,1TO11Y S,our c e Gene -..al Dyn~amics ?tG’!RE 13 56 inventory would provide a 33 percent reduction in F-16 lead time. Figure 14

  2. Oracle Database Common Bottleneck Issues Analysis%Oracle数据库常见的瓶颈问题分析

    Institute of Scientific and Technical Information of China (English)

    李文鹏

    2011-01-01

    Oracle database as the world's largest database companies at home and abroad has been applied widely.Article on the current Oracle database common bottleneck issues analyzed and discussed.%Oracle数据库作为全球第一大数据库厂商,在国内外获得了广泛应用。文章对目前Oracle数据库常见的瓶颈问题进行了分析探讨。

  3. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

    Directory of Open Access Journals (Sweden)

    Damien C Tully

    2016-05-01

    Full Text Available Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU, we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

  4. Chikungunya virus 3' untranslated region: adaptation to mosquitoes and a population bottleneck as major evolutionary forces.

    Directory of Open Access Journals (Sweden)

    Rubing Chen

    Full Text Available The 3' untranslated genome region (UTR of arthropod-borne viruses is characterized by enriched direct repeats (DRs and stem-loop structures. Despite many years of theoretical and experimental study, on-going positive selection on the 3'UTR had never been observed in 'real-time,' and the role of the arbovirus 3'UTR remains poorly understood. We observed a lineage-specific 3'UTR sequence pattern in all available Asian lineage of the mosquito-borne alphavirus, chikungunya virus (CHIKV (1958-2009, including complicated mutation and duplication patterns of the long DRs. Given that a longer genome is usually associated with less efficient replication, we hypothesized that the fixation of these genetic changes in the Asian lineage 3'UTR was due to their beneficial effects on adaptation to vectors or hosts. Using reverse genetic methods, we examined the functional importance of each direct repeat. Our results suggest that adaptation to mosquitoes, rather than to mammalian hosts, is a major evolutionary force on the CHIKV 3'UTR. Surprisingly, the Asian 3'UTR appeared to be inferior to its predicted ancestral sequence for replication in both mammals and mosquitoes, suggesting that its fixation in Asia was not a result of directional selection. Rather, it may have resulted from a population bottleneck during its introduction from Africa to Asia. We propose that this introduction of a 3'UTR with deletions led to genetic drift and compensatory mutations associated with the loss of structural/functional constraints, followed by two independent beneficial duplications and fixation due to positive selection. Our results provide further evidence that the limited epidemic potential of the Asian CHIKV strains resulted from founder effects that reduced its fitness for efficient transmission by mosquitoes there.

  5. Science Driven Supercomputing Architectures: AnalyzingArchitectural Bottlenecks with Applications and Benchmark Probes

    Energy Technology Data Exchange (ETDEWEB)

    Kamil, S.; Yelick, K.; Kramer, W.T.; Oliker, L.; Shalf, J.; Shan,H.; Strohmaier, E.

    2005-09-26

    There is a growing gap between the peak speed of parallel computing systems and the actual delivered performance for scientific applications. In general this gap is caused by inadequate architectural support for the requirements of modern scientific applications, as commercial applications and the much larger market they represent, have driven the evolution of computer architectures. This gap has raised the importance of developing better benchmarking methodologies to characterize and to understand the performance requirements of scientific applications, to communicate them efficiently to influence the design of future computer architectures. This improved understanding of the performance behavior of scientific applications will allow improved performance predictions, development of adequate benchmarks for identification of hardware and application features that work well or poorly together, and a more systematic performance evaluation in procurement situations. The Berkeley Institute for Performance Studies has developed a three-level approach to evaluating the design of high end machines and the software that runs on them: (1) A suite of representative applications; (2) A set of application kernels; and (3) Benchmarks to measure key system parameters. The three levels yield different type of information, all of which are useful in evaluating systems, and enable NSF and DOE centers to select computer architectures more suited for scientific applications. The analysis will further allow the centers to engage vendors in discussion of strategies to alleviate the present architectural bottlenecks using quantitative information. These may include small hardware changes or larger ones that may be out interest to non-scientific workloads. Providing quantitative models to the vendors allows them to assess the benefits of technology alternatives using their own internal cost-models in the broader marketplace, ideally facilitating the development of future computer

  6. Science Driven Supercomputing Architectures: AnalyzingArchitectural Bottlenecks with Applications and Benchmark Probes

    Energy Technology Data Exchange (ETDEWEB)

    Kamil, S.; Yelick, K.; Kramer, W.T.; Oliker, L.; Shalf, J.; Shan,H.; Strohmaier, E.

    2005-09-26

    There is a growing gap between the peak speed of parallelcomputing systems and the actual delivered performance for scientificapplications. In general this gap is caused by inadequate architecturalsupport for the requirements of modern scientific applications, ascommercial applications and the much larger market they represent, havedriven the evolution of computer architectures. This gap has raised theimportance of developing better benchmarking methodologies tocharacterize and to understand the performance requirements of scientificapplications, to communicate them efficiently to influence the design offuture computer architectures. This improved understanding of theperformance behavior of scientific applications will allow improvedperformance predictions, development of adequate benchmarks foridentification of hardware and application features that work well orpoorly together, and a more systematic performance evaluation inprocurement situations. The Berkeley Institute for Performance Studieshas developed a three-level approach to evaluating the design of high endmachines and the software that runs on them: 1) A suite of representativeapplications; 2) A set of application kernels; and 3) Benchmarks tomeasure key system parameters. The three levels yield different type ofinformation, all of which are useful in evaluating systems, and enableNSF and DOE centers to select computer architectures more suited forscientific applications. The analysis will further allow the centers toengage vendors in discussion of strategies to alleviate the presentarchitectural bottlenecks using quantitative information. These mayinclude small hardware changes or larger ones that may be out interest tonon-scientific workloads. Providing quantitative models to the vendorsallows them to assess the benefits of technology alternatives using theirown internal cost-models in the broader marketplace, ideally facilitatingthe development of future computer architectures more suited forscientific

  7. IDENTIFYING BOTTLENECKS FOR APPROPRIATE INFANT FEEDING IN URBAN SLUMS, ALIGARH CITY.

    Directory of Open Access Journals (Sweden)

    Saira Mehnaz

    2012-04-01

    Full Text Available Introduction: Urban population is increasing rapidly. Majority of these families are poor or landless farmers and labourers, who settle down in peri-urban areas, creating slums. Urban slums are thus growing at an alarming rate. The present study was carried out with the general objective of identifying factors which prevent access to health services. Objectives: 1. To determine the prevalence of stunting, wasting, and underweight in infants and young children. 2. To determine presence of certain micro-environmental and socioeconomic factors associated with poor nutritional status of infants and children. Methodology: Baseline study was carried out in Oct –Nov 2009 (as a part of another ongoing study and data was collected in 110 Mothers who had delivered children during the last one month. In Oct 2010 these families were visited again the infants were followed up. 39 families had shifted to another location or emigrated back to their parent state or village mostly in search of seasonal employment as reported by neighbours. One family refused to cooperate. . Two infants had died. Remaining 68 Mothers were interviewed in friendly informal manner after taking consent for study. Results: (35.4% study subjects had migrated to other areas, as reported by neighbours. Of the 68 mothers interviewed during follow up visit, previous baseline record showed that a majority were 20-30 years of age. , only 2 mothers (2.9% had exclusively breastfed for 6 months. 46 (67.6% said they had not been contacted by any health worker during the last 3 months. All 68 children were malnourished. Immunization status was poor and 94.1% children had suffered from some illness in the last one month. Conclusion: Migration is a problem which makes it difficult for providers to give continuity of care. Capacity building of the community can reduce the the bottlenecks leading to marginalization and exclusion of slum mothers from the mainstream urban health services.

  8. Transcriptome population genomics reveals severe bottleneck and domestication cost in the African rice (Oryza glaberrima).

    Science.gov (United States)

    Nabholz, Benoit; Sarah, Gautier; Sabot, François; Ruiz, Manuel; Adam, Hélène; Nidelet, Sabine; Ghesquière, Alain; Santoni, Sylvain; David, Jacques; Glémin, Sylvain

    2014-05-01

    The African cultivated rice (Oryza glaberrima) was domesticated in West Africa 3000 years ago. Although less cultivated than the Asian rice (O. sativa), O. glaberrima landraces often display interesting adaptation to rustic environment (e.g. drought). Here, using RNA-seq technology, we were able to compare more than 12,000 transcripts between 9 O. glaberrima, 10 wild O. barthii and one O. meridionalis individuals. With a synonymous nucleotide diversity πs = 0.0006 per site, O. glaberrima appears as the least genetically diverse crop grass ever documented. Using approximate Bayesian computation, we estimated that O. glaberrima experienced a severe bottleneck during domestication. This demographic scenario almost fully accounts for the pattern of genetic diversity across O. glaberrima genome as we detected very few outliers regions where positive selection may have further impacted genetic diversity. Moreover, the large excess of derived nonsynonymous substitution that we detected suggests that the O. glaberrima population suffered from the 'cost of domestication'. In addition, we used this genome-scale data set to demonstrate that (i) O. barthii genetic diversity is positively correlated with recombination rate and negatively with gene density, (ii) expression level is negatively correlated with evolutionary constraint, and (iii) one region on chromosome 5 (position 4-6 Mb) exhibits a clear signature of introgression with a yet unidentified Oryza species. This work represents the first genome-wide survey of the African rice genetic diversity and paves the way for further comparison between the African and the Asian rice, notably regarding the genetics underlying domestication traits.

  9. Raptor mortality in wind farms of southern Spain: mitigation measures on a major migration bottleneck area

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, Antonio-Roman Munoz; Lucas, Manuela De; Casado, Eva; Ferrer, Miguel

    2011-07-01

    Full text: To assess and monitor the impact of wind farms on fauna is crucial if we want to achieve ecologically sustainable development of this renewable energy resource. Today there are clear evidences that the probability of raptor collision depends critically on species behaviour and weather conditions, and the topographic factors related to each windmill. In our study area EIA were not able to predict this differential risk and in these circumstances mitigating the causes of bird mortality becomes a task of major importance, especially to those wind farms located in the Strait of Gibraltar, a water crossing of 14 km at its shortest distance acting as a major migration bottleneck for Paleo-African soaring migrants. We collected all available information on raptor collision from 1992, when the first wind farm was installed, and from 2005 until present a total of 262 turbines, grouped into 20 wind farms, were surveyed in a daily basis through a surveillance program with the main goal of register the actual mortality of birds. A total of 1291 raptors of 19 species were found of which 78.5% correspond to two species, the griffon vulture (Gyps fulvus) and the kestrel (Falco tinnunculus). In order to mitigate the impact on raptors, and particularly on the griffon vulture, in 2007 a program based on selective stopping of turbines was imposed, in collaboration with the environmental competent authority, on new approved projects. During 2008 there was a reduction in mortality by 48%, which remained in 2009 with a remarkably lower economic cost. An analysis of the temporal collision patterns will be presented and discussed, with special attention to those species suffering higher mortality rate, and to those who have some degree of threat. (Author)

  10. Epigeic earthworms exert a bottleneck effect on microbial communities through gut associated processes.

    Directory of Open Access Journals (Sweden)

    María Gómez-Brandón

    Full Text Available BACKGROUND: Earthworms play a critical role in organic matter decomposition because of the interactions they establish with microorganisms. The ingestion, digestion, assimilation of organic material in the gut and then casting is the first step in earthworm-microorganism interactions. The current knowledge of these direct effects is still limited for epigeic earthworm species, mainly those living in man-made environments. Here we tested whether and to what extent the earthworm Eisenia andrei is capable of altering the microbiological properties of fresh organic matter through gut associated processes; and if these direct effects are related to the earthworm diet. METHODOLOGY: To address these questions we determined the microbial community structure (phospholipid fatty acid profiles and microbial activity (fluorescein diacetate hydrolysis in the earthworm casts derived from three types of animal manure (cow, horse and pig manure, which differed in microbial composition. PRINCIPAL FINDINGS: The passage of the organic material through the gut of E. andrei reduced the total microbial biomass irrespective of the type of manure, and resulted in a decrease in bacterial biomass in all the manures; whilst leaving the fungi unaffected in the egested materials. However, unlike the microbial biomass, no such reduction was detected in the total microbial activity of cast samples derived from the pig manure. Moreover, no differences were found between cast samples derived from the different types of manure with regards to microbial community structure, which provides strong evidence for a bottleneck effect of worm digestion on microbial populations of the original material consumed. CONCLUSIONS/SIGNIFICANCE: Our data reveal that earthworm gut is a major shaper of microbial communities, thereby favouring the existence of a reduced but more active microbial population in the egested materials, which is of great importance to understand how biotic interactions

  11. Population aging and migrant workers: bottlenecks in tuberculosis control in rural China.

    Directory of Open Access Journals (Sweden)

    Sumedh Bele

    Full Text Available BACKGROUND: Tuberculosis is a serious global health problem. Its paradigms are shifting through time, especially in rapidly developing countries such as China. Health providers in China are at the forefront of the battle against tuberculosis; however, there are few empirical studies on health providers' perspectives on the challenges they face in tuberculosis control at the county level in China. This study was conducted among health providers to explore their experiences with tuberculosis control in order to identify bottlenecks and emerging challenges in controlling tuberculosis in rural China. METHODS: A qualitative approach was used. Semi-structured, in-depth interviews were conducted with 17 health providers working in various positions within the health system of one rural county (ZJG of China. Data were analyzed based on thematic content analysis using MAXQDA 10 qualitative data analysis software. RESULTS: Health providers reported several problems in tuberculosis control in ZJG county. Migrant workers and the elderly were repeatedly documented as the main obstacles in effective tuberculosis control in the county. At a personal level, doctors showed their frustration with the lack of new drugs for treating tuberculosis patients, and their opinions varied regarding incentives for referring patients. CONCLUSION: The results suggest that several problems still remain for controlling tuberculosis in rural China. Tuberculosis control efforts need to make reaching the most vulnerable populations a priority and encourage local health providers to adopt innovative practices in the local context based on national guidelines to achieve the best results. Considerable changes in China's National Tuberculosis Control Program are needed to tackle these emerging challenges faced by health workers at the county level.

  12. Reconstruction of a beech population bottleneck using archival demographic information and Bayesian analysis of genetic data.

    Science.gov (United States)

    Lander, Tonya A; Oddou-Muratorio, Sylvie; Prouillet-Leplat, Helene; Klein, Etienne K

    2011-12-01

    Range expansion and contraction has occurred in the history of most species and can seriously impact patterns of genetic diversity. Historical data about range change are rare and generally appropriate for studies at large scales, whereas the individual pollen and seed dispersal events that form the basis of geneflow and colonization generally occur at a local scale. In this study, we investigated range change in Fagus sylvatica on Mont Ventoux, France, using historical data from 1838 to the present and approximate Bayesian computation (ABC) analyses of genetic data. From the historical data, we identified a population minimum in 1845 and located remnant populations at least 200 years old. The ABC analysis selected a demographic scenario with three populations, corresponding to two remnant populations and one area of recent expansion. It also identified expansion from a smaller ancestral population but did not find that this expansion followed a population bottleneck, as suggested by the historical data. Despite a strong support to the selected scenario for our data set, the ABC approach showed a low power to discriminate among scenarios on average and a low ability to accurately estimate effective population sizes and divergence dates, probably due to the temporal scale of the study. This study provides an unusual opportunity to test ABC analysis in a system with a well-documented demographic history and identify discrepancies between the results of historical, classical population genetic and ABC analyses. The results also provide valuable insights into genetic processes at work at a fine spatial and temporal scale in range change and colonization.

  13. Epigeic Earthworms Exert a Bottleneck Effect on Microbial Communities through Gut Associated Processes

    Science.gov (United States)

    Gómez-Brandón, María; Aira, Manuel; Lores, Marta; Domínguez, Jorge

    2011-01-01

    Background Earthworms play a critical role in organic matter decomposition because of the interactions they establish with microorganisms. The ingestion, digestion, assimilation of organic material in the gut and then casting is the first step in earthworm-microorganism interactions. The current knowledge of these direct effects is still limited for epigeic earthworm species, mainly those living in man-made environments. Here we tested whether and to what extent the earthworm Eisenia andrei is capable of altering the microbiological properties of fresh organic matter through gut associated processes; and if these direct effects are related to the earthworm diet. Methodology To address these questions we determined the microbial community structure (phospholipid fatty acid profiles) and microbial activity (fluorescein diacetate hydrolysis) in the earthworm casts derived from three types of animal manure (cow, horse and pig manure), which differed in microbial composition. Principal Findings The passage of the organic material through the gut of E. andrei reduced the total microbial biomass irrespective of the type of manure, and resulted in a decrease in bacterial biomass in all the manures; whilst leaving the fungi unaffected in the egested materials. However, unlike the microbial biomass, no such reduction was detected in the total microbial activity of cast samples derived from the pig manure. Moreover, no differences were found between cast samples derived from the different types of manure with regards to microbial community structure, which provides strong evidence for a bottleneck effect of worm digestion on microbial populations of the original material consumed. Conclusions/Significance Our data reveal that earthworm gut is a major shaper of microbial communities, thereby favouring the existence of a reduced but more active microbial population in the egested materials, which is of great importance to understand how biotic interactions within the decomposer

  14. Childhood leukemia genetic bottleneck phenomenon related to TEL-AML1: the postulation by a mathematical model

    Institute of Scientific and Technical Information of China (English)

    Petar Ivanovski; Ivan Ivanovski; Dimitrije Nikoli(c); Ivana Jovanovi(c)

    2012-01-01

    Childhood leukemia bottleneck phenomenon is the most mysterious corollary of the prenatal origin discovery of leukemogenic chromosome translocations.The bottleneck is evidence that leukemia initiation,by in utero acquired chromosome translocations that generate functional fusion genes,is far more common than the incidence rate of corresponding leukemia.For childhood TEL-AML1+ acute lymphoblastic leukemia (ALL) this equates to approximately 100 times.Practically this means that among a hundred children born with TEL-AML1 fusion gene,only one child will later in its life develop ALL.The key data necessary for unraveling of this mystery were discovered in 2002.It was the level of TEL-AML1 + cells' frequency.The bottleneck is caused by the very low body TEL-AML1 + cell count.Only one out of a thousand B cells carries TEL-AML1 fusion gene.TEL-AML1+ body cell count is low because TEL-AML1 fusion is generated at cell level of 10a to 10-4 just during the late fetal lymphopoiesis i.e.after the 36th gestational week.

  15. Childhood leukemia genetic bottleneck phenomenon related to TEL-AML1: the postulation by a mathematical model.

    Science.gov (United States)

    Ivanovski, Petar; Ivanovski, Ivan; Nikolić, Dimitrije; Jovanović, Ivana

    2012-03-01

    Childhood leukemia bottleneck phenomenon is the most mysterious corollary of the prenatal origin discovery of leukemogenic chromosome translocations. The bottleneck is evidence that leukemia initiation, by in utero acquired chromosome translocations that generate functional fusion genes, is far more common than the incidence rate of corresponding leukemia. For childhood TEL-AML1(+) acute lymphoblastic leukemia (ALL) this equates to approximately 100 times. Practically this means that among a hundred children born with TEL-AML1 fusion gene, only one child will later in its life develop ALL. The key data necessary for unraveling of this mystery were discovered in 2002. It was the level of TEL-AML1(+) cells’ frequency. The bottleneck is caused by the very low body TEL-AML1(+) cell count. Only one out of a thousand B cells carries TEL-AML1 fusion gene. TEL-AML1(+) body cell count is low because TEL-AML1 fusion is generated at cell level of 10(-3) to 10(-4) just during the late fetal lymphopoiesis i.e. after the 36th gestational week.

  16. A Qualitative Study of Bottlenecks and Causes of Fractions for Dedicated Incomes of Health Centers and Solutions for their Reduction

    Science.gov (United States)

    Tabrizi, Jafar Sadegh; Alidoost, Saeide; Abdolahi, Hossein Mashhadi

    2016-01-01

    Background: Primary health care is one of effective approaches for improving public health. Providing optimal cares requires supplication of various resources such as financial resources. “Fractions of incomes” in health centers is one of the remarkable problems for the domain of financial resources management in Iran. This study was aimed to identify bottlenecks and causes of fractions for incomes in health centers and solutions for their reduction. Methods: The current study was conducted in a qualitative phenomenology method in East Azerbaijan province of Iran in 2014. Data collection method was focus group discussion and semi-structured interview. Purposive sampling was used for selecting participants. Focus group discussions and interviews were conducted based on pre-prepared guidance and continued till data saturation. Validity of guidance was approved by qualitative studies experts. Data were analyzed using content analysis method. Results: Based on the opinions of participants, two and six themes were respectively extracted for bottlenecks of fractions and causes and solutions for their reduction. Themes for bottlenecks of fractions included cash (monetary) and non-cash (non-monetary) fractions and themes for causes and solutions included causes and solutions for fractions per capita, insurance deductions, fractions related to sending documents, registration fractions, discounts fractions, and incomplete deposit of cash incomes. Conclusion: All cash and non-cash incomes of health centers are subject to fractions. The causes of fractions are related to the whole process of converting services to incomes and insurance requirements. Identified solutions and interventions also focus on these areas.

  17. Acoustic-optical phonon up-conversion and hot-phonon bottleneck in lead-halide perovskites

    Science.gov (United States)

    Yang, Jianfeng; Wen, Xiaoming; Xia, Hongze; Sheng, Rui; Ma, Qingshan; Kim, Jincheol; Tapping, Patrick; Harada, Takaaki; Kee, Tak W.; Huang, Fuzhi; Cheng, Yi-Bing; Green, Martin; Ho-Baillie, Anita; Huang, Shujuan; Shrestha, Santosh; Patterson, Robert; Conibeer, Gavin

    2017-01-01

    The hot-phonon bottleneck effect in lead-halide perovskites (APbX3) prolongs the cooling period of hot charge carriers, an effect that could be used in the next-generation photovoltaics devices. Using ultrafast optical characterization and first-principle calculations, four kinds of lead-halide perovskites (A=FA+/MA+/Cs+, X=I−/Br−) are compared in this study to reveal the carrier-phonon dynamics within. Here we show a stronger phonon bottleneck effect in hybrid perovskites than in their inorganic counterparts. Compared with the caesium-based system, a 10 times slower carrier-phonon relaxation rate is observed in FAPbI3. The up-conversion of low-energy phonons is proposed to be responsible for the bottleneck effect. The presence of organic cations introduces overlapping phonon branches and facilitates the up-transition of low-energy modes. The blocking of phonon propagation associated with an ultralow thermal conductivity of the material also increases the overall up-conversion efficiency. This result also suggests a new and general method for achieving long-lived hot carriers in materials. PMID:28106061

  18. Acoustic-optical phonon up-conversion and hot-phonon bottleneck in lead-halide perovskites.

    Science.gov (United States)

    Yang, Jianfeng; Wen, Xiaoming; Xia, Hongze; Sheng, Rui; Ma, Qingshan; Kim, Jincheol; Tapping, Patrick; Harada, Takaaki; Kee, Tak W; Huang, Fuzhi; Cheng, Yi-Bing; Green, Martin; Ho-Baillie, Anita; Huang, Shujuan; Shrestha, Santosh; Patterson, Robert; Conibeer, Gavin

    2017-01-20

    The hot-phonon bottleneck effect in lead-halide perovskites (APbX3) prolongs the cooling period of hot charge carriers, an effect that could be used in the next-generation photovoltaics devices. Using ultrafast optical characterization and first-principle calculations, four kinds of lead-halide perovskites (A=FA(+)/MA(+)/Cs(+), X=I(-)/Br(-)) are compared in this study to reveal the carrier-phonon dynamics within. Here we show a stronger phonon bottleneck effect in hybrid perovskites than in their inorganic counterparts. Compared with the caesium-based system, a 10 times slower carrier-phonon relaxation rate is observed in FAPbI3. The up-conversion of low-energy phonons is proposed to be responsible for the bottleneck effect. The presence of organic cations introduces overlapping phonon branches and facilitates the up-transition of low-energy modes. The blocking of phonon propagation associated with an ultralow thermal conductivity of the material also increases the overall up-conversion efficiency. This result also suggests a new and general method for achieving long-lived hot carriers in materials.

  19. Acoustic-optical phonon up-conversion and hot-phonon bottleneck in lead-halide perovskites

    Science.gov (United States)

    Yang, Jianfeng; Wen, Xiaoming; Xia, Hongze; Sheng, Rui; Ma, Qingshan; Kim, Jincheol; Tapping, Patrick; Harada, Takaaki; Kee, Tak W.; Huang, Fuzhi; Cheng, Yi-Bing; Green, Martin; Ho-Baillie, Anita; Huang, Shujuan; Shrestha, Santosh; Patterson, Robert; Conibeer, Gavin

    2017-01-01

    The hot-phonon bottleneck effect in lead-halide perovskites (APbX3) prolongs the cooling period of hot charge carriers, an effect that could be used in the next-generation photovoltaics devices. Using ultrafast optical characterization and first-principle calculations, four kinds of lead-halide perovskites (A=FA+/MA+/Cs+, X=I-/Br-) are compared in this study to reveal the carrier-phonon dynamics within. Here we show a stronger phonon bottleneck effect in hybrid perovskites than in their inorganic counterparts. Compared with the caesium-based system, a 10 times slower carrier-phonon relaxation rate is observed in FAPbI3. The up-conversion of low-energy phonons is proposed to be responsible for the bottleneck effect. The presence of organic cations introduces overlapping phonon branches and facilitates the up-transition of low-energy modes. The blocking of phonon propagation associated with an ultralow thermal conductivity of the material also increases the overall up-conversion efficiency. This result also suggests a new and general method for achieving long-lived hot carriers in materials.

  20. Contact transmission of influenza virus between ferrets imposes a looser bottleneck than respiratory droplet transmission allowing propagation of antiviral resistance

    Science.gov (United States)

    Frise, Rebecca; Bradley, Konrad; van Doremalen, Neeltje; Galiano, Monica; Elderfield, Ruth A.; Stilwell, Peter; Ashcroft, Jonathan W.; Fernandez-Alonso, Mirian; Miah, Shahjahan; Lackenby, Angie; Roberts, Kim L.; Donnelly, Christl A.; Barclay, Wendy S.

    2016-01-01

    Influenza viruses cause annual seasonal epidemics and occasional pandemics. It is important to elucidate the stringency of bottlenecks during transmission to shed light on mechanisms that underlie the evolution and propagation of antigenic drift, host range switching or drug resistance. The virus spreads between people by different routes, including through the air in droplets and aerosols, and by direct contact. By housing ferrets under different conditions, it is possible to mimic various routes of transmission. Here, we inoculated donor animals with a mixture of two viruses whose genomes differed by one or two reverse engineered synonymous mutations, and measured the transmission of the mixture to exposed sentinel animals. Transmission through the air imposed a tight bottleneck since most recipient animals became infected by only one virus. In contrast, a direct contact transmission chain propagated a mixture of viruses suggesting the dose transferred by this route was higher. From animals with a mixed infection of viruses that were resistant and sensitive to the antiviral drug oseltamivir, resistance was propagated through contact transmission but not by air. These data imply that transmission events with a looser bottleneck can propagate minority variants and may be an important route for influenza evolution. PMID:27430528

  1. Analysis of talent bottleneck of chain retailing business%连锁零售企业人才瓶颈问题浅析

    Institute of Scientific and Technical Information of China (English)

    赵根良

    2012-01-01

    In the chain retailing business operation and management, talent is the foundation of its success and continuous development. With the rapid expansion of chain retailing business, chain retailing business in China has relatively serious talent bottleneck problem. Based on the analysis of the situation and reasons of Chinese chain retailing business talent bottleneck, this article puts forward counter- measures and suggestions to solve Chinese chain retailing business talent bottleneck problem.%在分析了我国连锁零售企业人才瓶颈的现状和原因的基础上,提出了解决这一问题的对策和建议。

  2. Is integration and survival of newborn neurons the bottleneck for effective neural repair by endogenous neural precursor cells?

    Directory of Open Access Journals (Sweden)

    Ann eTurnley

    2014-02-01

    Full Text Available After two decades of research the existence of adult neural precursor cells and the phenomenon of adult neurogenesis is well established. However, there has been little or no effective harnessing of these endogenous cells to promote functional neuronal replacement following neural injury or disease. Neural precursor cells can respond to neural damage by proliferating, migrating to the site of injury and differentiating into neuronal or glial lineages. However, after a month or so, very few or no newborn neurons can be detected, suggesting that even though neuroblasts are generated, they generally fail to survive as mature neurons and contribute to the local circuitry. Is this lack of survival and integration one of the major bottlenecks that inhibits effective neuronal replacement and subsequent repair of the nervous system following injury or disease? In this perspective article the possibility that this bottleneck can be targeted to enhance the integration and subsequent survival of newborn neurons will be explored and will suggest some possible mechanisms that may need to be modulated for this to occur.

  3. Differences in Strength and Timing of the mtDNA Bottleneck between Zebrafish Germline and Non-germline Cells

    Directory of Open Access Journals (Sweden)

    Auke B.C. Otten

    2016-07-01

    Full Text Available We studied the mtDNA bottleneck in zebrafish to elucidate size, timing, and variation in germline and non-germline cells. Mature zebrafish oocytes contain, on average, 19.0 × 106 mtDNA molecules with high variation between oocytes. During embryogenesis, the mtDNA copy number decreases to ∼170 mtDNA molecules per primordial germ cell (PGC, a number similar to that in mammals, and to ∼50 per non-PGC. These occur at the same developmental stage, implying considerable variation in mtDNA copy number in (non-PGCs of the same female, dictated by variation in the mature oocyte. The presence of oocytes with low mtDNA numbers, if similar in humans, could explain how (de novo mutations can reach high mutation loads within a single generation. High mtDNA copy numbers in mature oocytes are established by mtDNA replication during oocyte development. Bottleneck differences between germline and non-germline cells, due to early differentiation of PGCs, may account for different distribution patterns of familial mutations.

  4. Resistance of virus to extinction on bottleneck passages: Study of a decaying and fluctuating pattern of fitness loss

    Science.gov (United States)

    Lázaro, Ester; Escarmís, Cristina; Pérez-Mercader, Juan; Manrubia, Susanna C.; Domingo, Esteban

    2003-01-01

    RNA viruses display high mutation rates and their populations replicate as dynamic and complex mutant distributions, termed viral quasispecies. Repeated genetic bottlenecks, which experimentally are carried out through serial plaque-to-plaque transfers of the virus, lead to fitness decrease (measured here as diminished capacity to produce infectious progeny). Here we report an analysis of fitness evolution of several low fitness foot-and-mouth disease virus clones subjected to 50 plaque-to-plaque transfers. Unexpectedly, fitness decrease, rather than being continuous and monotonic, displayed a fluctuating pattern, which was influenced by both the virus and the state of the host cell as shown by effects of recent cell passage history. The amplitude of the fluctuations increased as fitness decreased, resulting in a remarkable resistance of virus to extinction. Whereas the frequency distribution of fitness in control (independent) experiments follows a log-normal distribution, the probability of fitness values in the evolving bottlenecked populations fitted a Weibull distribution. We suggest that multiple functions of viral genomic RNA and its encoded proteins, subjected to high mutational pressure, interact with cellular components to produce this nontrivial, fluctuating pattern. PMID:12960384

  5. Engineering of bottlenecks in Rhizopus oryzae lipase production in Pichia pastoris using the nitrogen source-regulated FLD1 promoter.

    Science.gov (United States)

    Resina, David; Maurer, Michael; Cos, Oriol; Arnau, Carolina; Carnicer, Marc; Marx, Hans; Gasser, Brigitte; Valero, Francisco; Mattanovich, Diethard; Ferrer, Pau

    2009-09-01

    The yeast Pichia pastoris has been previously used for extracellular expression of a Rhizopus oryzae lipase (Rol). However, limitations in Rol folding and secretion through the cell wall became apparent when producing it in fed-batch cultivations. In this study, we have investigated the effect of combining two cell engineering strategies to alleviate putative bottlenecks in Rol secretion, namely the constitutive expression of the induced form of the Saccharomyces cerevisiae unfolded protein response transcriptional factor Hac1 and the deletion of the GAS1 gene encoding beta-1,3-glucanosyltransglycosylase, GPI-anchored to the outer leaflet of the plasma membrane, playing a key role in yeast cell wall assembly. The performance of these engineered Rol-producing strains has been compared in fed-batch cultivations set at a low specific growth rate of about 0.005 h-(1). It was found that Rol overexpression in a P. pastoris strain expressing constitutively the induced form of S. cerevisiae Hac1 and the deletion of GAS1 resulted in about a 3-fold and 4-fold increase in the overall process specific productivity, respectively, whereas the double mutant HAC1/deltagas1 strain yielded about a 7-fold increase. Overall, these results reflect the multiplicity of physiological bottlenecks at different levels/steps throughout the Rol synthesis, secretion and excretion processes in P. pastoris.

  6. Conservation genetics of the alligator snapping turtle: cytonuclear evidence of range-wide bottleneck effects and unusually pronounced geographic structure

    Science.gov (United States)

    Echelle, A.A.; Hackler, J.C.; Lack, Justin B.; Ballard, S. R.; Roman, J.; Fox, S. F.; Leslie,, David M.; Van Den Bussche, Ronald A.

    2010-01-01

    A previous mtDNA study indicated that female-mediated gene flow was extremely rare among alligator snapping turtle populations in different drainages of the Gulf of Mexico. In this study, we used variation at seven microsatellite DNA loci to assess the possibility of male-mediated gene flow, we augmented the mtDNA survey with additional sampling of the large Mississippi River System, and we evaluated the hypothesis that the consistently low within-population mtDNA diversity reflects past population bottlenecks. The results show that dispersal between drainages of the Gulf of Mexico is rare (F STmsat  = 0.43, ΦSTmtDNA = 0.98). Past range-wide bottlenecks are indicated by several genetic signals, including low diversity for microsatellites (1.1–3.9 alleles/locus; H e = 0.06–0.53) and mtDNA (h = 0.00 for most drainages; π = 0.000–0.001). Microsatellite data reinforce the conclusion from mtDNA that the Suwannee River population might eventually be recognized as a distinct taxonomic unit. It was the only population showing fixation or near fixation for otherwise rare microsatellite alleles. Six evolutionarily significant units are recommended on the basis of reciprocal mtDNA monophyly and high levels of microsatellite DNA divergence.

  7. The Effects of Juvenile Competitive Bottleneck on Dynamic Behavior%幼年竞争瓶颈对动力学行为的影响

    Institute of Scientific and Technical Information of China (English)

    唐光耀

    2011-01-01

    The effect of juvenile competitive bottlenecks on population dynamics is investigated by formulating food web models with a nonlinear maturation rate.The food web system consists of a resource (R),an intermediate consumer (N) and a predator (P).Our results show,with weak bottlenecks,that a juvenile bottleneck in the predator's life history has a larger impact than a bottleneck in the consumer.In the food web model with bottleneck for the predator,there are two possible internal steady states,and the system can exhibit consumer-predator equilibrium and consumer equilibrium as two alternative stable states,as well as the consumer equilibrium and predator equilibrium as two alternative stable states.No bistable phenomenon induced by bottleneck can be detected,and nothing new happens in system with consumer bottlenecks.Further,we show that a bottleneck can change the net effect of the intermediate consumer on predator from facilitation to inhibition or from inhibition to facilitation,which case occurs depends on both the choice of bottleneck and the initial states of systems.%通过建立具有非线性成熟率的食物网模型研究了幼年竞争瓶颈对种群动力学行为的影响,结论显示当竞争瓶颈比较弱的时,捕食者生活史中的幼年瓶颈对系统的影响要大于成年.模型存在两种可能的共存态或双稳定性,即消费者-捕食者和消费者平衡态共存,但是瓶颈不能诱导系统的双稳定性.进一步研究说明了选择不同的瓶颈或初始条件,瓶颈能够改变次级消费者对捕食者的净影响.

  8. 作业车间区间型多属性瓶颈识别方法%Interval multi-attribute bottleneck identification in job shop

    Institute of Scientific and Technical Information of China (English)

    王军强; 陈剑; 王烁; 郭银洲; 张映锋; 孙树栋

    2013-01-01

    Aiming at the Job shop bottleneck identification problem under random disturbance resulting in the difficulty of obtaining the determinate value of machine feature attribute, interval form was used to describe these uncertain attributes of machine. Furthermore, a new interval multi-attribute bottleneck identification model was established, and an interval TOPSIS bottleneck identification approach was proposed. By considering the close relationship between bottleneck utilization and bottleneck identification, an integrated framework, under which they could be solved simultaneously, was presented. This framework included two layers. In the first layer of bottleneck utilization, the Plant-Simulation platform was used to simulate random disturbance including equipment failure. Genetic algorithm (GA) was applied to perform optimization and simulation for the scheduling problems under the random disturbance and the optimum scheduling solution was obtained. In the second layer of bottleneck identification, based on scheduling optimization, interval TOPSIS bottleneck identification approach was proposed to identify bottleneck machines with considerations of multiple feature attributes. Comparing the proposed approach with machine utilization, bottleneck occurrence rate and shifting bottleneck detection method in the existing literatures, the results demonstrated the effectiveness of this approach. Finally, the influence of machining cost and material cost on bottleneck identification was analyzed.%针对扰动情形下作业车间瓶颈识别时机器的特征属性难以用确定值表示的问题,采用区间形式描述机器特征属性,构建了区间型多属性瓶颈识别模型,提出了区间TOPSIS多属性瓶颈识别方法.考虑瓶颈识别与瓶颈利用的紧密关系,提出了先进行瓶颈利用再进行瓶颈识别的统一框架.其中瓶颈利用层基于Plant-Simulation 仿真平台设置了机器故障等随机扰动,采用遗传算法对扰动情形

  9. Bypassing the central bottleneck after single-task practice in the psychological refractory period paradigm: evidence for task automatization and greedy resource recruitment.

    Science.gov (United States)

    Maquestiaux, François; Laguë-Beauvais, Maude; Ruthruff, Eric; Bherer, Louis

    2008-10-01

    In this research, the controversial issue of whether the central bottleneck can be bypassed through task automatization was investigated. To examine this issue, participants received six single-task practice sessions with an auditory-vocal task (low vs. high pitch). We then assessed dual-task performance using the analytically tractable psychological refractory period (PRP) paradigm, in which the highly practiced auditory-vocal task was presented as Task 2, along with an unpracticed visual-manual Task 1. The results provide evidence of bottleneck bypass for virtually all the participants (17 out of 20). Several converging tests suggest that the bottleneck reemerged, however, in a follow-up experiment with tasks presented in the opposite order (auditory-vocal Task 1 and visual-manual Task 2). One possible explanation is that tasks greedily recruit central resources when available, even though they can operate without central resources when unavailable.

  10. Probabilistic physical characteristics of phase transitions at highway bottlenecks: incommensurability of three-phase and two-phase traffic-flow theories.

    Science.gov (United States)

    Kerner, Boris S; Klenov, Sergey L; Schreckenberg, Michael

    2014-05-01

    Physical features of induced phase transitions in a metastable free flow at an on-ramp bottleneck in three-phase and two-phase cellular automaton (CA) traffic-flow models have been revealed. It turns out that at given flow rates at the bottleneck, to induce a moving jam (F → J transition) in the metastable free flow through the application of a time-limited on-ramp inflow impulse, in both two-phase and three-phase CA models the same critical amplitude of the impulse is required. If a smaller impulse than this critical one is applied, neither F → J transition nor other phase transitions can occur in the two-phase CA model. We have found that in contrast with the two-phase CA model, in the three-phase CA model, if the same smaller impulse is applied, then a phase transition from free flow to synchronized flow (F → S transition) can be induced at the bottleneck. This explains why rather than the F → J transition, in the three-phase theory traffic breakdown at a highway bottleneck is governed by an F → S transition, as observed in real measured traffic data. None of two-phase traffic-flow theories incorporates an F → S transition in a metastable free flow at the bottleneck that is the main feature of the three-phase theory. On the one hand, this shows the incommensurability of three-phase and two-phase traffic-flow theories. On the other hand, this clarifies why none of the two-phase traffic-flow theories can explain the set of fundamental empirical features of traffic breakdown at highway bottlenecks.

  11. Local mate competition and transmission bottlenecks: a new model for understanding malaria parasite and other sex ratios.

    Science.gov (United States)

    Neal, Allison T; Taylor, Peter D

    2014-12-21

    The local mate competition model from sex ratio theory predicts female-biased sex ratios in populations that are highly subdivided during mating, and is thought to accord well with the population structure of malaria parasites. However, the selective advantage of female-biased sex ratios comes from the resulting increase in total reproductive output, an advantage the transmission biology of malaria parasite likely reduces. We develop a mathematical model to determine how bottlenecks in transmission that cause diminishing fitness returns from female production affect sex ratio evolution. We develop four variations of this model that incorporate whether or not parasite clones have the ability to detect others that occupy the same host and whether or not the number of clones affects the total mating population size. Our model indicates that transmission bottlenecks favor less female-biased sex ratios than those predicted under LMC. This effect is particularly pronounced if clones have no information about the presence of coexisting clones and the number of mating individuals per patch is fixed. The model could extend our understanding of malaria parasite sex ratios in three main ways. First, it identifies inconsistencies between the theoretical predictions and the data presented in a previous study, and proposes revised predictions that are more consistent with underlying biology of the parasite. Second, it may account for the positive association between parasite density and sex ratio observed within and between some species. Third, it predicts a relationship between mortality rates in the vector and sex ratios, which appears to be supported by the little existing data we have. While the inspiration for this model came from malaria parasites, it should apply to any system in which per capita dispersal success diminishes with increasing numbers of females in a patch.

  12. Inflammatory genital infections mitigate a severe genetic bottleneck in heterosexual transmission of subtype A and C HIV-1.

    Directory of Open Access Journals (Sweden)

    Richard E Haaland

    2009-01-01

    Full Text Available The HIV-1 epidemic in sub-Saharan Africa is driven largely by heterosexual transmission of non-subtype B viruses, of which subtypes C and A are predominant. Previous studies of subtype B and subtype C transmission pairs have suggested that a single variant from the chronically infected partner can establish infection in their newly infected partner. However, in subtype A infected individuals from a sex worker cohort and subtype B individuals from STD clinics, infection was frequently established by multiple variants. This study examined over 1750 single-genome amplified viral sequences derived from epidemiologically linked subtype C and subtype A transmission pairs very early after infection. In 90% (18/20 of the pairs, HIV-1 infection is initiated by a single viral variant that is derived from the quasispecies of the transmitting partner. In addition, the virus initiating infection in individuals who were infected by someone other than their spouse was characterized to determine if genital infections mitigated the severe genetic bottleneck observed in a majority of epidemiologically linked heterosexual HIV-1 transmission events. In nearly 50% (3/7 of individuals infected by someone other than their spouse, multiple genetic variants from a single individual established infection. A statistically significant association was observed between infection by multiple genetic variants and an inflammatory genital infection in the newly infected individual. Thus, in the vast majority of HIV-1 transmission events in cohabiting heterosexual couples, a single genetic variant establishes infection. Nevertheless, this severe genetic bottleneck can be mitigated by the presence of inflammatory genital infections in the at risk partner, suggesting that this restriction on genetic diversity is imposed in large part by the mucosal barrier.

  13. Microsatellite analysis of a population crash and bottleneck in the Mauna Kea silversword, Argyroxiphium sandwicense ssp. sandwicense (Asteraceae), and its implications for reintroduction.

    Science.gov (United States)

    Friar, E A; Ladoux, T; Roalson, E H; Robichaux, R H

    2000-12-01

    The Mauna Kea silversword, Argyroxiphium sandwicense ssp. sandwicense, has experienced both a severe population crash associated with an increase in alien ungulate populations on Mauna Kea, and a population bottleneck associated with reintroduction. In this paper, we address the genetic consequences of both demographic events using eight microsatellite loci. The population crash was not accompanied by a significant reduction in number of alleles or heterozygosity. However, the population bottleneck was accompanied by significant reductions in observed number of alleles, effective number of alleles, and expected heterozygosity, though not in observed heterozygosity. The effective size of the population bottleneck was calculated using both observed heterozygosities and allele frequency variances. Both methods corroborated the historical census size of the population bottleneck of at most three individuals. The results suggest that: (i) small populations, even those that result from severe reductions in historical population size and extent, are not necessarily genetically depauperate; and (ii) species reintroduction plans need to be conceived and implemented carefully, with due consideration to the genetic impact of sampling for reintroduction.

  14. Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow.

    Science.gov (United States)

    Kerner, Boris S

    2015-12-01

    We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S→F instability. Whereas the S→F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S→F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S→F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S→F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S→F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S→F instability governs traffic breakdown-a phase transition from free flow to synchronized flow (F→S transition) at the bottleneck: The nucleation nature of the S→F instability explains the metastability of free flow with respect to an F→S transition at the bottleneck.

  15. Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow

    Science.gov (United States)

    Kerner, Boris S.

    2015-12-01

    We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S →F instability. Whereas the S →F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S →F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S →F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S →F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S →F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S →F instability governs traffic breakdown—a phase transition from free flow to synchronized flow (F →S transition) at the bottleneck: The nucleation nature of the S →F instability explains the metastability of free flow with respect to an F →S transition at the bottleneck.

  16. Bottleneck Analysis of the Minimum Cost Problem for the Generalized Network Based on Augmented Forest Structure%基于增广森林结构的一般网络最小费用问题瓶颈分析

    Institute of Scientific and Technical Information of China (English)

    江永亨; 王军; 金以慧

    2003-01-01

    The bottleneck analysis of the minimum cost problem for the generalized network (MCPGN) is dis-cussed. The analysis is based on the network simplex algorithm, which gains negative cost graphs by constructingaugmented forest structure, then augments flows on the negative cost graphs until the optimal revolution is gained.Bottleneck structure is presented after analyzing the augmented forest structure. The negative cost augmentedgraphs are constructed with the bottleneck structure. The arcs that block the negative cost augmented graph arethe elements of the bottleneck. The bottleneck analysis for the generalized circulation problem, the minimum circu-lation problem and the circulation problem are discussed respectively as the basal problems, then that for MCPGNis achieved. An example is presented at the end.

  17. Transmission of equine influenza virus during an outbreak is characterized by frequent mixed infections and loose transmission bottlenecks.

    Directory of Open Access Journals (Sweden)

    Joseph Hughes

    2012-12-01

    Full Text Available The ability of influenza A viruses (IAVs to cross species barriers and evade host immunity is a major public health concern. Studies on the phylodynamics of IAVs across different scales - from the individual to the population - are essential for devising effective measures to predict, prevent or contain influenza emergence. Understanding how IAVs spread and evolve during outbreaks is critical for the management of epidemics. Reconstructing the transmission network during a single outbreak by sampling viral genetic data in time and space can generate insights about these processes. Here, we obtained intra-host viral sequence data from horses infected with equine influenza virus (EIV to reconstruct the spread of EIV during a large outbreak. To this end, we analyzed within-host viral populations from sequences covering 90% of the infected yards. By combining gene sequence analyses with epidemiological data, we inferred a plausible transmission network, in turn enabling the comparison of transmission patterns during the course of the outbreak and revealing important epidemiological features that were not apparent using either approach alone. The EIV populations displayed high levels of genetic diversity, and in many cases we observed distinct viral populations containing a dominant variant and a number of related minor variants that were transmitted between infectious horses. In addition, we found evidence of frequent mixed infections and loose transmission bottlenecks in these naturally occurring populations. These frequent mixed infections likely influence the size of epidemics.

  18. LONG-ORBITAL-PERIOD PREPOLARS CONTAINING EARLY K-TYPE DONOR STARS. BOTTLENECK ACCRETION MECHANISM IN ACTION

    Energy Technology Data Exchange (ETDEWEB)

    Tovmassian, G.; González–Buitrago, D.; Zharikov, S. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apartado Postal 877, Ensenada, Baja California, 22800 México (Mexico); Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Campus Box 3255, Chapel Hill, NC 27599 (United States); Miroshnichenko, A. S., E-mail: gag@astro.unam.mx, E-mail: dgonzalez@astro.unam.mx, E-mail: zhar@astro.unam.mx [Department of Physics and Astronomy, University of North Carolina at Greensboro, Greensboro, NC 27402-6170 (United States)

    2016-03-01

    We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems.

  19. Ancient DNA reveals substantial genetic diversity in the California Condor (Gymnogyps californianus) prior to a population bottleneck

    Science.gov (United States)

    D'Elia, Jesse; Haig, Susan M.; Mullins, Thomas D.; Miller, Mark P.

    2016-01-01

    Critically endangered species that have undergone severe population bottlenecks often have little remaining genetic variation, making it difficult to reconstruct population histories to apply in reintroduction and recovery strategies. By using ancient DNA techniques, it is possible to combine genetic evidence from the historical population with contemporary samples to provide a more complete picture of a species' genetic variation across its historical range and through time. Applying this approach, we examined changes in the mitochondrial DNA (mtDNA) control region (526 base pairs) of the endangered California Condor (Gymnogyps californianus). Results showed a >80% reduction in unique haplotypes over the past 2 centuries. We found no spatial sorting of haplotypes in the historical population; the periphery of the range contained haplotypes that were common throughout the historical range. Direct examination of mtDNA from California Condor museum specimens provided a new window into historical population connectivity and genetic diversity showing: (1) a substantial loss of haplotypes, which is consistent with the hypothesis that condors were relatively abundant in the nineteenth century, but declined rapidly as a result of human-caused mortality; and (2) no evidence of historical population segregation, meaning that the available genetic data offer no cause to avoid releasing condors in unoccupied portions of their historical range.

  20. Consequences of extreme life history traits on population persistence: do short-lived gobies face demographic bottlenecks?

    Science.gov (United States)

    Lefèvre, Carine D.; Nash, Kirsty L.; González-Cabello, Alonso; Bellwood, David R.

    2016-06-01

    The majority of coral reef goby species are short-lived, with some highly abundant species living less than 100 d. To understand the role and consequences of this extreme life history in shaping coral reef fish populations, we quantitatively documented the structure of small reef fish populations over a 26-month period (>14 short-lived fish generations) at an inshore reef on the Great Barrier Reef, Australia. Most species with life spans >1 yr, such as pomacentrids, exhibited a peak in recruitment during the austral summer, driving seasonal changes in the small fish community composition. In contrast, there were no clear changes in goby community composition, despite the abundance of short-lived, high turnover species. Species of Eviota, the most abundant gobiid genus observed, showed remarkably similar demographic profiles year-round, with consistent densities of adults as well as recently recruited juveniles. Our results demonstrate ongoing recruitment of these small cryptic fishes, which appears to compensate for an exceptionally short life span on the reef. Our results suggest that gobiid populations are able to overcome demographic limitations, and by maintaining reproduction, larval survival and recruitment throughout the year, they may avoid population bottlenecks. These findings also underline the potential trophodynamic importance of these small species; because of this constant turnover, Eviota species and other short-lived fishes may be particularly valuable contributors to the flow of energy on coral reefs, underpinning the year-round trophic structure.

  1. Hanging on the line – on the need to assess the risk to global submarine telecommunications infrastructure – an example of the Hawaiian "bottleneck" and Australia

    Directory of Open Access Journals (Sweden)

    D. Dominey-Howes

    2009-04-01

    Full Text Available National economies are becoming increasingly dependent on the global telecommunications system – and in particular, its submarine cable infrastructure. We note that a variety of natural hazard processes are capable of damaging and destroying this infrastructure, both in deep water and at the coast. Some places within the global telecommunications system are already known to be bottlenecks or "choke points". Hawaii is just such a choke point and interestingly, Hawaii is also affected by numerous large magnitude natural hazard processes. Any damage to the submarine telecommunications infrastructure routed through Hawaii could result in significant impacts on the electronic flow of data and voice traffic, negatively affecting dependent economies such as Australia. We propose that proper risk assessments be undertaken at all bottlenecks in the global telecommunications system affected by natural hazards (such as tsunami. We use Hawaii as an example of the sort of research that should be undertaken.

  2. Widening Synthesis Bottlenecks: Realization of Ultrafast and Continuous-Flow Synthesis of High-Silica Zeolite SSZ-13 for NOx Removal.

    Science.gov (United States)

    Liu, Zhendong; Wakihara, Toru; Oshima, Kazunori; Nishioka, Daisuke; Hotta, Yuusuke; Elangovan, Shanmugam P; Yanaba, Yutaka; Yoshikawa, Takeshi; Chaikittisilp, Watcharop; Matsuo, Takeshi; Takewaki, Takahiko; Okubo, Tatsuya

    2015-05-04

    Characteristics of zeolite formation, such as being kinetically slow and thermodynamically metastable, are the main bottlenecks that obstruct a fast zeolite synthesis. We present an ultrafast route, the first of its kind, to synthesize high-silica zeolite SSZ-13 in 10 min, instead of the several days usually required. Fast heating in a tubular reactor helps avoid thermal lag, and the synergistic effect of addition of a SSZ-13 seed, choice of the proper aluminum source, and employment of high temperature prompted the crystallization. Thanks to the ultra-short period of synthesis, we established a continuous-flow preparation of SSZ-13. The fast-synthesized SSZ-13, after copper-ion exchange, exhibits outstanding performance in the ammonia selective catalytic reduction (NH3 -SCR) of nitrogen oxides (NOx ), showing it to be a superior catalyst for NOx removal. Our results indicate that the formation of high-silica zeolites can be extremely fast if bottlenecks are effectively widened.

  3. Survival Analyses of Traffic Flow Breakdown at Urban Expressway Bottlenecks%城市快速路瓶颈交通流失效生存分析

    Institute of Scientific and Technical Information of China (English)

    孙剑; 张娟

    2013-01-01

    瓶颈处交通流失效(breakdown)是导致快速路拥堵的重要原因,其致因则是交通需求、驾驶行为及设施设计等多因素交互作用的结果.针对快速路常发性瓶颈失效的随机特征,基于海量检测数据,提出了快速路瓶颈失效的生存分析模型.该模型首先以速度、密度组合阈值法判断失效是否发生;然后统计失效发生时刻及发生前的交通流参数,利用生存函数描述失效发生概率与瓶颈通行能力的关系;进一步采用Cox回归模型分析瓶颈失效的影响因素.上海市内环3个典型双车道常发性瓶颈点277个交通流失效事件分析表明,在50%的失效概率下,3个瓶颈每车道通行能力分别为1341,1 552,1 662 veh·h-1;通过调控主线车速及驶入匝道流量可对瓶颈失效起到有效的保护作用.利用该方法可精细化确定瓶颈点概率通行能力,并为快速路主动交通管理措施设计提供理论依据.%A major cause for the urban expressway congestion is the traffic flow breakdown at bottlenecks due to the combined effects of traffic demand, driving behavior and design of traffic facilities.For the probabilistic nature of breakdown at urban expressway recurring bottlenecks, survival-analysis models of breakdown were proposed based on a large scale of detector data.First, breakdowns were identified according to speed and density thresholds, and then traffic parameters before or during breakdown interval were collected, and the relationship between the breakdown probability and the bottleneck capacity was described by survival function.Finally, factors of bottleneck breakdowns were analyzed with Cox regression models.An analysis of 277 breakdown events at three typical two-lane recurring bottlenecks in the inner ring in Shanghai shows that the traffic capacities of a single lane at these bottlenecks are 1 341, 1 552 and 1 662 veh·h-1 respectively when the probability of breakdown is at 50 %.To adjust or

  4. Transmission of human mtDNA heteroplasmy in the Genome of the Netherlands families: support for a variable-size bottleneck

    Science.gov (United States)

    Li, Mingkun; Rothwell, Rebecca; Vermaat, Martijn; Wachsmuth, Manja; Schröder, Roland; Laros, Jeroen F.J.; van Oven, Mannis; de Bakker, Paul I.W.; Bovenberg, Jasper A.; van Duijn, Cornelia M.; van Ommen, Gert-Jan B.; Slagboom, P. Eline; Swertz, Morris A.; Wijmenga, Cisca; Kayser, Manfred; Boomsma, Dorret I.; Zöllner, Sebastian; de Knijff, Peter; Stoneking, Mark

    2016-01-01

    Although previous studies have documented a bottleneck in the transmission of mtDNA genomes from mothers to offspring, several aspects remain unclear, including the size and nature of the bottleneck. Here, we analyze the dynamics of mtDNA heteroplasmy transmission in the Genomes of the Netherlands (GoNL) data, which consists of complete mtDNA genome sequences from 228 trios, eight dizygotic (DZ) twin quartets, and 10 monozygotic (MZ) twin quartets. Using a minor allele frequency (MAF) threshold of 2%, we identified 189 heteroplasmies in the trio mothers, of which 59% were transmitted to offspring, and 159 heteroplasmies in the trio offspring, of which 70% were inherited from the mothers. MZ twin pairs exhibited greater similarity in MAF at heteroplasmic sites than DZ twin pairs, suggesting that the heteroplasmy MAF in the oocyte is the major determinant of the heteroplasmy MAF in the offspring. We used a likelihood method to estimate the effective number of mtDNA genomes transmitted to offspring under different bottleneck models; a variable bottleneck size model provided the best fit to the data, with an estimated mean of nine individual mtDNA genomes transmitted. We also found evidence for negative selection during transmission against novel heteroplasmies (in which the minor allele has never been observed in polymorphism data). These novel heteroplasmies are enhanced for tRNA and rRNA genes, and mutations associated with mtDNA diseases frequently occur in these genes. Our results thus suggest that the female germ line is able to recognize and select against deleterious heteroplasmies. PMID:26916109

  5. A wide range of 3243A>G/tRNALeu(UUR (MELAS mutation loads may segregate in offspring through the female germline bottleneck.

    Directory of Open Access Journals (Sweden)

    Francesco Pallotti

    Full Text Available Segregation of mutant mtDNA in human tissues and through the germline is debated, with no consensus about the nature and size of the bottleneck hypothesized to explain rapid generational shifts in mutant loads. We investigated two maternal lineages with an apparently different inheritance pattern of the same pathogenic mtDNA 3243A>G/tRNALeu(UUR (MELAS mutation. We collected blood cells, muscle biopsies, urinary epithelium and hair follicles from 20 individuals, as well as oocytes and an ovarian biopsy from one female mutation carrier, all belonging to the two maternal lineages to assess mutant mtDNA load, and calculated the theoretical germline bottleneck size (number of segregating units. We also evaluated "mother-to-offspring" segregations from the literature, for which heteroplasmy assessment was available in at least three siblings besides the proband. Our results showed that mutation load was prevalent in skeletal muscle and urinary epithelium, whereas in blood cells there was an inverse correlation with age, as previously reported. The histoenzymatic staining of the ovarian biopsy failed to show any cytochrome-c-oxidase defective oocyte. Analysis of four oocytes and one offspring from the same unaffected mother of the first family showed intermediate heteroplasmic mutant loads (10% to 75%, whereas very skewed loads of mutant mtDNA (0% or 81% were detected in five offspring of another unaffected mother from the second family. Bottleneck size was 89 segregating units for the first mother and 84 for the second. This was remarkably close to 88, the number of "segregating units" in the "mother-to-offspring" segregations retrieved from literature. In conclusion, a wide range of mutant loads may be found in offspring tissues and oocytes, resulting from a similar theoretical bottleneck size.

  6. Global change ecotoxicology: Identification of early life history bottlenecks in marine invertebrates, variable species responses and variable experimental approaches.

    Science.gov (United States)

    Byrne, M

    2012-05-01

    Climate change is a threat to marine biota because increased atmospheric CO₂ is causing ocean warming, acidification, hypercapnia and decreased carbonate saturation. These stressors have toxic effects on invertebrate development. The persistence and success of populations requires all ontogenetic stages be completed successfully and, due to their sensitivity to environmental stressors, developmental stages may be a population bottleneck in a changing ocean. Global change ecotoxicology is being used to identify the marine invertebrate developmental stages vulnerable to climate change. This overview of research, and the methodologies used, shows that most studies focus on acidification, with few studies on ocean warming, despite a long history of research on developmental thermotolerance. The interactive effects of stressors are poorly studied. Experimental approaches differ among studies. Fertilization in many species exhibits a broad tolerance to warming and/or acidification, although different methodologies confound inter-study comparisons. Early development is susceptible to warming and most calcifying larvae are sensitive to acidification/increased pCO₂. In multistressor studies moderate warming diminishes the negative impact of acidification on calcification in some species. Development of non-calcifying larvae appears resilient to near-future ocean change. Although differences in species sensitivities to ocean change stressors undoubtedly reflect different tolerance levels, inconsistent handling of gametes, embryos and larvae probably influences different research outcomes. Due to the integrative 'developmental domino effect', life history responses will be influenced by the ontogenetic stage at which experimental incubations are initiated. Exposure to climate change stressors from early development (fertilization where possible) in multistressor experiments is needed to identify ontogenetic sensitivities and this will be facilitated by more consistent

  7. Homopolymeric tract heteroplasmy in mtDNA from tissues and single oocytes: Support for a genetic bottleneck

    Energy Technology Data Exchange (ETDEWEB)

    Marchington, D.R.; Hartshorne, G.M.; Barlow, D.; Poulton, J. [Univ. of Oxford (United Kingdom)

    1997-02-01

    While mtDNA polymorphisms at single base positions are common, the overwhelming majority of the mitochondrial genomes within a single individual are usually identical. When there is a point-mutation difference between a mother and her offspring, there may be a complete switching of mtDNA type within a single generation. It is generally assumed that there is a genetic bottleneck whereby a single or small number of founder mtDNA(s) populate the organism, but it is not known at which stages the restriction/amplification of mtDNA subtype(s) occur, and this uncertainty impedes antenatal diagnosis for mtDNA disorders. Length polymorphisms in homopolymeric tracts have been demonstrated in the large noncoding region of mtDNA. We have developed a new method, T-PCR (trimmed PCR), to quantitate heteroplasmy for two of these tracts (D310 and D16189). D310 variation is sufficient to indicate clonal origins of tissues and single oocytes. Tissues from normal individuals often possessed more than one length variant (heteroplasmy). However, there was no difference in the pattern of the length variants between somatic tissues in any control individual when bulk samples were taken. Oocytes from normal women undergoing in vitro fertilization were frequently heteroplasmic for length variants, and in two cases the modal length of the D310 tract differed in individual oocytes from the same woman. These data suggest that a restriction/amplification event, which we attribute to clonal expansion of founder mtDNA(s), has occurred by the time oocytes are mature, although further segregation may occur at a later stage. In contrast to controls, the length distribution of the D310 tract varied between tissues in a patient with heteroplasmic mtDNA rearrangements, suggesting that these mutants influence segregation. These findings have important implications for the genetic counselling of patients with pathogenic mtDNA mutations. 21 refs., 5 figs., 1 tab.

  8. Bioenergetics-based modeling of Plasmodium falciparum metabolism reveals its essential genes, nutritional requirements, and thermodynamic bottlenecks

    Science.gov (United States)

    Chiappino-Pepe, Anush; Ataman, Meriç

    2017-01-01

    Novel antimalarial therapies are urgently needed for the fight against drug-resistant parasites. The metabolism of malaria parasites in infected cells is an attractive source of drug targets but is rather complex. Computational methods can handle this complexity and allow integrative analyses of cell metabolism. In this study, we present a genome-scale metabolic model (iPfa) of the deadliest malaria parasite, Plasmodium falciparum, and its thermodynamics-based flux analysis (TFA). Using previous absolute concentration data of the intraerythrocytic parasite, we applied TFA to iPfa and predicted up to 63 essential genes and 26 essential pairs of genes. Of the 63 genes, 35 have been experimentally validated and reported in the literature, and 28 have not been experimentally tested and include previously hypothesized or novel predictions of essential metabolic capabilities. Without metabolomics data, four of the genes would have been incorrectly predicted to be non-essential. TFA also indicated that substrate channeling should exist in two metabolic pathways to ensure the thermodynamic feasibility of the flux. Finally, analysis of the metabolic capabilities of P. falciparum led to the identification of both the minimal nutritional requirements and the genes that can become indispensable upon substrate inaccessibility. This model provides novel insight into the metabolic needs and capabilities of the malaria parasite and highlights metabolites and pathways that should be measured and characterized to identify potential thermodynamic bottlenecks and substrate channeling. The hypotheses presented seek to guide experimental studies to facilitate a better understanding of the parasite metabolism and the identification of targets for more efficient intervention. PMID:28333921

  9. Population genetics and the effects of a severe bottleneck in an ex situ population of critically endangered Hawaiian tree snails.

    Science.gov (United States)

    Price, Melissa R; Hadfield, Michael G

    2014-01-01

    As wild populations decline, ex situ propagation provides a potential bank of genetic diversity and a hedge against extinction. These programs are unlikely to succeed if captive populations do not recover from the severe bottleneck imposed when they are founded with a limited number of individuals from remnant populations. In small captive populations allelic richness may be lost due to genetic drift, leading to a decline in fitness. Wild populations of the Hawaiian tree snail Achatinella lila, a hermaphroditic snail with a long life history, have declined precipitously due to introduced predators and other human impacts. A captive population initially thrived after its founding with seven snails, exceeding 600 captive individuals in 2009, but drastically declined in the last five years. Measures of fitness were examined from 2,018 captive snails that died between 1998 and 2012, and compared with genotypic data for six microsatellite loci from a subset of these deceased snails (N = 335), as well as live captive snails (N = 198) and wild snails (N = 92). Surprisingly, the inbreeding coefficient (Fis) declined over time in the captive population, and is now approaching values observed in the 2013 wild population, despite a significant decrease in allelic richness. However, adult annual survival and fecundity significantly declined in the second generation. These measures of fitness were positively correlated with heterozygosity. Snails with higher measures of heterozygosity had more offspring, and third generation offspring with higher measures of heterozygosity were more likely to reach maturity. These results highlight the importance of maintaining genetic diversity in captive populations, particularly those initiated with a small number of individuals from wild remnant populations. Genetic rescue may allow for an increase in genetic diversity in the captive population, as measures of heterozygosity and rarified allelic richness were higher in wild tree

  10. Human migration through bottlenecks from Southeast Asia into East Asia during Last Glacial Maximum revealed by Y chromosomes.

    Science.gov (United States)

    Cai, Xiaoyun; Qin, Zhendong; Wen, Bo; Xu, Shuhua; Wang, Yi; Lu, Yan; Wei, Lanhai; Wang, Chuanchao; Li, Shilin; Huang, Xingqiu; Jin, Li; Li, Hui

    2011-01-01

    Molecular anthropological studies of the populations in and around East Asia have resulted in the discovery that most of the Y-chromosome lineages of East Asians came from Southeast Asia. However, very few Southeast Asian populations had been investigated, and therefore, little was known about the purported migrations from Southeast Asia into East Asia and their roles in shaping the genetic structure of East Asian populations. Here, we present the Y-chromosome data from 1,652 individuals belonging to 47 Mon-Khmer (MK) and Hmong-Mien (HM) speaking populations that are distributed primarily across Southeast Asia and extend into East Asia. Haplogroup O3a3b-M7, which appears mainly in MK and HM, indicates a strong tie between the two groups. The short tandem repeat network of O3a3b-M7 displayed a hierarchical expansion structure (annual ring shape), with MK haplotypes being located at the original point, and the HM and the Tibeto-Burman haplotypes distributed further away from core of the network. Moreover, the East Asian dominant haplogroup O3a3c1-M117 shows a network structure similar to that of O3a3b-M7. These patterns indicate an early unidirectional diffusion from Southeast Asia into East Asia, which might have resulted from the genetic drift of East Asian ancestors carrying these two haplogroups through many small bottle-necks formed by the complicated landscape between Southeast Asia and East Asia. The ages of O3a3b-M7 and O3a3c1-M117 were estimated to be approximately 19 thousand years, followed by the emergence of the ancestors of HM lineages out of MK and the unidirectional northward migrations into East Asia.

  11. Microscopic Theory of Traffic Flow Instability Governing Traffic Breakdown at Highway Bottlenecks: Growing Wave of Increase in Speed in Synchronized Flow

    CERN Document Server

    Kerner, Boris S

    2015-01-01

    We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability as an S$\\rightarrow$F instability. Whereas the S$\\rightarrow$F instability leads to a local {\\it increase in speed} (growing acceleration wave), in contrast, the classical traffic flow instability introduced in 50s--60s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local {\\it decrease in speed} (growing deceleration wave). We have found that the S$\\rightarrow$F instability can occur only, if there is a finite time delay in driver over-acceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S$\\rightarrow$F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that ...

  12. Whole-genome sequencing of six Mauritian Cynomolgus macaques (Macaca fascicularis) reveals a genome-wide pattern of polymorphisms under extreme population bottleneck.

    Science.gov (United States)

    Osada, Naoki; Hettiarachchi, Nilmini; Adeyemi Babarinde, Isaac; Saitou, Naruya; Blancher, Antoine

    2015-03-23

    Cynomolgus macaques (Macaca fascicularis) were introduced to the island of Mauritius by humans around the 16th century. The unique demographic history of the Mauritian cynomolgus macaques provides the opportunity to not only examine the genetic background of well-established nonhuman primates for biomedical research but also understand the effect of an extreme population bottleneck on the pattern of polymorphisms in genomes. We sequenced the whole genomes of six Mauritian cynomolgus macaques and obtained an average of 20-fold coverage of the genome sequences for each individual. The overall level of nucleotide diversity was 23% smaller than that of the Malaysian cynomolgus macaques, and a reduction of low-frequency polymorphisms was observed. In addition, we also confirmed that the Mauritian cynomolgus macaques were genetically closer to a representative of the Malaysian population than to a representative of the Indochinese population. Excess of nonsynonymous polymorphisms in low frequency, which has been observed in many other species, was not very strong in the Mauritian samples, and the proportion of heterozygous nonsynonymous polymorphisms relative to synonymous polymorphisms is higher within individuals in Mauritian than Malaysian cynomolgus macaques. Those patterns indicate that the extreme population bottleneck made purifying selection overwhelmed by the power of genetic drift in the population. Finally, we estimated the number of founding individuals by using the genome-wide site frequency spectrum of the six samples. Assuming a simple demographic scenario with a single bottleneck followed by exponential growth, the estimated number of founders (∼20 individuals) is largely consistent with previous estimates.

  13. Effect of Driver Behavior on Spatiotemporal Congested Traffic Patterns at Highway Bottlenecks in the Framework of Three-Phase Traffic Theory

    CERN Document Server

    Kerner, Boris S

    2010-01-01

    We present results of numerical simulations of the effect of driver behavior on spatiotemporal congested traffic patterns that result from traffic breakdown at an on-ramp bottleneck. The simulations are made with the Kerner-Klenov stochastic traffic flow model in the framework of three-phase traffic theory. Different diagrams of congested patterns at the bottleneck associated with different driver behavioral characteristics are found and compared each other. An adaptive cruise control (ACC) in the framework of three-phase traffic theory introduced by the author (called a "driver alike ACC" (DA-ACC)) is discussed. The effect of DA-ACC-vehicles on traffic flow, in which without the DA-ACC-vehicles traffic congestion occurs at the bottleneck, is numerically studied. We show that DA-ACC-vehicles improve traffic flow considerably without any reduction in driving comfort. It is found that there is a critical percentage of DA-ACC-vehicles in traffic flow: If the percentage of the DA-ACC-vehicle exceeds the critical ...

  14. Sensitivity of Material-flow Bottleneck to Uncertain Environment in Job Shop%物料流瓶颈对制造车间不确定环境的敏感性研究

    Institute of Scientific and Technical Information of China (English)

    凌琳; 刘明周; 王强

    2013-01-01

    The method for measuring the sensitivity of the bottleneck degree to the bottleneck shifting factors was proposed. According to the material-flow bottleneck defining, the production capability and load were described from the perspectives of process speed and quality level, then the bottleneck index was constructed to characterize the degree of manufacturing unit blocking the material-flow ( that is bottleneck degree). Based on the measurement of the sensitivity of the bottleneck index to the single bottleneck shifting factor and DEMATEL method for analyzing the relationship of the factors, bottleneck shifting sensitivity index was built to measure the sensitive degree of bottleneck index to the uncertain environment. At the end of this thesis, an example for monitoring the bottleneck and measuring sensitive degree to the uncertain environment in job shop was given to prove the validation and practicability of bottleneck index and bottleneck shifting sensitivity index.%提出了物料流瓶颈对瓶颈漂移因素的敏感性度量方法.通过定义物料流瓶颈,从生产速率和生产质量两个方面综合度量制造单元生产能力和需求,并提出物料流瓶颈指数用于表征制造单元阻碍制造车间物料流流动平顺性的程度(即物料流瓶颈程度);分显性和隐性瓶颈漂移因素测度制造单元瓶颈指数对各因素的敏感性,并利用DEMATEL方法分析因素间的相互关联关系,在此基础上提出瓶颈漂移敏感指数度量物料流瓶颈对制造车间不确定环境的敏感程度;最后,通过对某一制造车间内物料流瓶颈和瓶颈程度对不确定环境的敏感性的度量和监测,验证了瓶颈指数和瓶颈漂移敏感指数的有效性和实用性.

  15. Achievements and bottlenecks in humanitarian demining EU-funded research: final results from the EC DELVE project

    Science.gov (United States)

    Sahli, Hichem; Bruschini, Claudio; Van Kempen, Luc; Schleijpen, Ric; den Breejen, Eric

    2008-04-01

    The EC DELVE Support Action project has analyzed the bottlenecks in the transfer of Humanitarian Demining (HD) technology from technology development to the use in the field, and drawn some lessons learned, basing itself on the assessment of the European Humanitarian Demining Research and Technology Development (RTD) situation from early 1990 until 2006. The situation at the European level was analyzed with emphasis on activities sponsored by the European Commission (EC). This was also done for four European countries and Japan, with emphasis on national activities. The developments in HD during the last 10 years underline the fact that in a number of cases demining related developments have been terminated or at least put on hold. The study also showed that the funding provided by the EC under the Framework Program for RTD has led directly to the creation of an extensive portfolio of Humanitarian Demining technology development projects. The latter provided a range of research and supporting measures addressing the critical issues identified as a result of the regulatory policies developed in the field of Humanitarian Demining over the last ten years. However, the range of instruments available to the EC to finance the necessary research and development were limited, to pre-competitive research. The EC had no tools or programs to directly fund actual product development. As a first consequence, the EC funding program for development of technology for Humanitarian Demining unfortunately proved to be largely unsuitable for the small-scale development needed in a field where there is only a very limited market. As a second consequence, most of the research has been demonstrator-oriented. Moreover, the timeframe for RTD in Humanitarian Demining has not been sufficiently synchronized with the timeframe of the EC policies and regulations. The separation of the Mine Action and RTD funding streams in the EC did also negatively affect the take-up of new technologies. As a

  16. Multi-bottleneck scheduling algorithm for large-scale Job Shop%大规模作业车间多瓶颈调度算法

    Institute of Scientific and Technical Information of China (English)

    翟颖妮; 孙树栋; 杨宏安; 牛刚刚; 袁宗寅

    2011-01-01

    To solve Large-Scale Job Shop Scheduling Problems(LSJSSP), a multi-bottleneck scheduling algorithm based on rolling horizon decomposition was proposed. This algorithm adopted critical path method to detect bottlenecks, and solved the LSJSSP by decomposing it into a series of sub-problems according to the process routines of the jobs. In the construction process of the sub-problems, the idea of load balanced distribution was proposed to distribute the load of each job in the sub-problems and to realize the stability of the solution process. In the solving process of the sub-problems. The bottleneck operations were scheduled by genetic algorithm, and the non-bottleneck operations were scheduled by dispatching rules according to the principle of "bottleneck machines lead non-bottleneck machines" in Theory of Constraints (TOC), the solving efficiency was improved. Through re-optimization process for the overlapping operations in the adjacent sub-problems and the strategy of evaluating the chromosome's fitness by the global solution, limitations of the decomposition and solving process were avoided, and the solution quality was improved. Simulation results showed that the proposed algorithm for LSJSSP was with satisfactory solution efficiency and quality.%针对大规模作业车间调度问题,提出一种基于滚动窗分解的多瓶颈调度算法.该算法基于关键路径法进行多瓶颈机器的识别,沿时域将大规模调度问题分解为多个子问题进行求解.在子问题创建过程中,提出负荷均衡分布的规则,使得各工件在各子问题中的负荷均匀分布,以实现算法求解过程的稳定性;在子问题的求解过程中,遵循约束理论中瓶颈机主导非瓶颈机的原则,采用瓶颈工序最优化调度、非瓶颈工序采用分派规则快速调度的调度策略,提高算法的求解效率;通过相邻子问题间的工序衔接再优化过程,以及全局解评价子问题染色体适应度值策略,有效避

  17. Joint Liability Model:Way to Break Microfinance Bottleneck%小组联保模式:突破微型金融发展的瓶颈

    Institute of Scientific and Technical Information of China (English)

    王杨; 刘冉; 胡亦秋; 乔海曙

    2011-01-01

    微型金融在我国的发展过程中遇到了成本、心理预期、风险和担保等瓶颈。由格莱珉银行率先提出的小组联保模式,是在微观层面上突破这些瓶颈的重要制度。对金融机构而言,小组联保模式能够缓解信息不对称、优化展望值、分散风险;对农户而言,小组联保模式能使其充分利用社会资本、为其提供交流平台。但小组联保模式仍存在一些尚需改善的地方。为更好地突破微型金融面临的瓶颈,应推进信用体系建设、完善激励约束机制、建立风险防范体系。%Microfinance's development in China has met some bottlenecks in terms of cost,risk,guarantee,and psychological expectation.Joint liability model,firstly put forward by Grameen Bank,is an important mechanism to break through these bottlenecks.For financial institutions,the model can help spread risk,overcome information asymmetry,and optimize the expectation value and for farmers,the model can help them take full advantage of social capital.However,there are still some problems.To ameliorate this mechanism and overcome these bottlenecks,relevant institutions should propel the construction of the credit system,improve the incentive and restraint mechanism,and establish risk prevention system.

  18. Resolución del “Lexicographic Bottleneck Assembly Line Balancing Problem” mediante métodos heurísticos

    OpenAIRE

    Chueca Closa, Ignacio

    2008-01-01

    El objetivo de este proyecto es la resolución, mediante métodos heurísticos, de una variante novedosa y poco tratada del Problema de Equilibrado de Líneas de Montaje o Assembly Line Balancing Problem (ALBP). Dentro del ALBP se trata la tipología de problema Lexicographic Bottleneck Assembly Line Balancing Problem (LB-ALBP), cuyo objetivo es: dado un número determinado de estaciones, minimizar el tiempo de la estación más cargada (tiempo de ciclo), posteriormente el tiempo de...

  19. Operational Capacity on Freeway Bottleneck Segment%高速公路瓶颈路段运营通行能力研究

    Institute of Scientific and Technical Information of China (English)

    吴德华; 邱志军

    2015-01-01

    高速公路瓶颈路段在发生交通拥堵后会引起运营通行能力突变现象,为了更加准确揭示瓶颈路段运营通行能力变化规律,引入非对称驾驶行为理论,改进Newell跟车模型,并对模型进行参数估计和应用分析.通过12个仿真场景及试验数据对比分析了改进模型和美国道路通行能力手册(2010)推荐模型的精确度,发现改进模型可以提高精度;分析了因车道减少导致的交通拥堵,发现关闭不同车道和车道数对运营通行能力影响结果不同,得出了相应的影响值;在一定交通量范围内,入口匝道和出口匝道交通量的增加都会导致主线拥堵路段运营通行能力的降低,并给出了最大降低幅度.研究结果可为缓解高速公路瓶颈路段交通拥堵提供借鉴.%The traffic congestion can cause operational capacity drop phenomenon on freeway bottleneck segment. To reveal the capacity diversification regular pattern, the asymmetric driver behavior theory is used to improve the Newell car-following model. The improved car-following model is calibrated and implemented in field data simulation. By 12 simulation scenarios and field data analysis, the results show that the improved Newell car-following model can increase accuracy in estimate the bottleneck operational capacity compared to the model that Highway Capacity Manual (HCM2010) provided. The traffic congestion due to the lane drop is analyzed, the operational capacity varied in condition close different lane and number of lanes, then the varied value is figured out. The operational capacity on major lane bottleneck segment decreases by changed the flow on on-ramp and off-ramp in range of certain flow change, and the most decreased value is calculated. In conclusion, the results can provide reference for migrate congestion on freeway bottleneck segment.

  20. The bottleneck and countermeasures on the company's certification%论企业认证中的瓶颈与对策

    Institute of Scientific and Technical Information of China (English)

    闫恩刚

    2012-01-01

    通过企业实施质量管理体系、环境与职业健康安全管理和技术标准体系欧共体安全技术法规CE认证,就认证与实施过程中,从体系的建立到运行控制,从内审到外审的认证过程,所反应出来的体系与运行、认证与体系、认证与实际现状、技术法规与认证之间的瓶颈,结合实际论述了其解决对策.%This quality management system implemented by business, environmental and occupational health and safety management system of European security and technical standards, technical regulations CE certification, the certification and implementation process, from creation to run the control system, from the outside audit to review the certification process, the reaction to run out of the system and the certification with the system, certification and the actual situation, between technical standards and certification bottleneck , the bottleneck with the actual discussion of the implementation of countermeasures.

  1. 中国MOOC发展现状与瓶颈研究%Research on the Current Situation and Bottlenecks of MOOC Development in China

    Institute of Scientific and Technical Information of China (English)

    王晶

    2016-01-01

    本文主要针对我国MOOC发展的现状和瓶颈进行分析研究,重点介绍了MOOC平台建设、SPOC模式应用以及专业技能教育MOOC的发展,从MOOC交流工具、学习成果认证、可持续发展三个方面对MOOC的瓶颈进行研究并提出建议,期望对今后MOOC更好的发展提供帮助。%This paper mainly analyzed and studied the current situation and bottlenecks of MOOC develop⁃ment in our country, focused on the introduction of MOOC platform establishment, SPOC mode application and the development of professional skills education MOOC, and studied MOOC bottlenecks from three aspects of MOOC communication tools, certification of learning outcomes, and sustainable development and put forward suggestions, hoping to provide assistance for the better development of MOOC in the future.

  2. Physician deficit in USA - where is the bottleneck? [Ärztemangel in den USA - wo wird es eng?

    Directory of Open Access Journals (Sweden)

    Walid, M. Sami

    2009-05-01

    Full Text Available [english] The population of physician professionals in the US has been carefully controlled over the last century to ensure profitable work for people in the profession and provide physician workforce for the nation. However, the emergence of managed care in the US has spurred speculations that the US will experience a substantial excess of physicians by the beginning of the 21st century. In light of these forecasts, the number of residency positions funded by Medicare has been restricted. Additionally, enrollment at allopathic medical schools has been decreasing over the last two decades of the Twentieth Century. It is now evident that those predictions were erroneous and that the current supply of physicians does not exceed the demand for their services. That is why the Association of American Medical Colleges now aims to increase the number of US medical school graduates by 3,000 yearly by the year 2015. However, even if this difficult mission can be accomplished, the US can still have a deficit of 200,000 physicians by the year 2020. The reason is the bottleneck that controls the flow of medical graduates aiming to enter residency programs and get clinical training in order to obtain the license required to practice medicine. With the restriction on the number of Medicare-funded residency positions in the US an increase in US medical school graduates will only displace an equal number of international medical graduates applying for residency positions and consequently reduce the number of international medical graduates who join the physician workforce. This will probably not increase the number of practicing physicians. Shortage of physicians will remain an issue and undeniably make access to medical care problematic for all citizens. [german] Im 20. Jahrhundert wurde die Zahl der Ärzte in den Vereinigten Staaten sorgfältig reguliert, um lohnende Arbeitsbedingungen im ärztlichen Beruf und die Versorgung mit Ärzten für die Bev

  3. Using 5S Field Management Activities to Promote the TOC Bottleneck Management in Workshop%运用5S现场管理活动推进车间实施TOC瓶颈管理

    Institute of Scientific and Technical Information of China (English)

    史丙强

    2014-01-01

    The 5S on-site management is the tool of production system to carry out TOC bottleneck management, and makes the TOC bottleneck management easy to work. Bottleneck management thought provides guidance and direction for the development of 5S on-site management work.%院5S现场管理是生产系统推行TOC瓶颈管理的工具,使TOC瓶颈管理工作开展简单易行;瓶颈管理的思想,为5S现场管理工作的开展提供指导,指明方向。

  4. 大规模无线网络中(X,S)-Bottleneck区域性能分析%Performance Analysis of (X, S)-Bottleneck Cell in Large-Scale Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    颜国风; 王建新; 陈淑红

    2012-01-01

    The performance analytical model for (X,S)-bottleneck cell is proposed and perform some probabilistic analysis on the performances of (X,S)-bottleneck cell, such as the probability of balance state, the transmission probability of a flow, and the throughput of (X,S)-bottleneck cell. To capture the essential aspects of (X,S)-bottleneck cell, two-hierarchy Quasi Birth-Death models (QBDs) are used to model the (X,S)-bottleneck cell. The general characters of (X,S)-bottleneck cell are govern by the first hierarchy QBDs, while the characters of each flow are captured by the second hierarchy QBDs. Based on the analytical model, a methodology to derive the balance-state probability of (X,S>bottleneck cell is proposed, and some theoretic ranges for the transmission probability of a flow and the throughput. The simulations show that the proposed model can analyze effectively the performance of (X,S)-bottleneck cell. The results are helpful for improving and managing wireless networks.%基于二层QBDs(quasi birth-death models),提出了一个(X,S)-bottleneck区域性能分析模型,(X,S)-bottleneck区域的特征通过第1层QBD模型描述,而经过(X,S)-bottleneck区域的每条流的特征由第2层QBD模型描述.基于该性能分析模型,对(X,S)-bottleneck区域的性能进行了一些概率分析,如(X,S)-bottleneck区域的平衡状态概率、经过该区域通信流的成功转发概率和吞吐量等,确定了上述概率及吞吐量的取值范围,仿真实验结果表明了该性能分析模型对于分析(X,S)-bottleneck区域性能的有效性.结论有助于无线网络通信性能的改进和管理.

  5. Development status, bottleneck and trend of China cosmetic industry%我国化妆品行业发展现状、瓶颈及趋势

    Institute of Scientific and Technical Information of China (English)

    郭华山

    2012-01-01

    China cosmetic market status and features were introduced, and its import and export data were analyzed. Meanwhile, both current problems and bottleneck in the process of cosmetic market development as well as future measures and strategies were pointed out. Finally, development trend of cosmetic industry was put forward.%对中国整个化妆品市场现状和特征进行了阐述,对2011年的进出口数据进行了深入分析。同时,指出了中国化妆品市场发展过程中遇到的问题、发展瓶颈以及今后几年的发展措施和战略。最后,对今后化妆品行业的发展趋势进行了总结。

  6. Vegetative propagation and its possible role as a genetic bottleneck in the shaping of the apple fruit crinkle viroid populations in apple and hop plants.

    Science.gov (United States)

    Sano, Teruo; Isono, Sayaka; Matsuki, Keigo; Kawaguchi-Ito, Yoko; Tanaka, Kazuaki; Kondo, Ken-ichi; Iijima, Akira; Bar-Joseph, Moshe

    2008-12-01

    Apple fruit crinkle viroid (AFCVd) infects apples and hops. To analyze the genetic diversity of AFCVd, nine apple and six hop isolates were collected from several locations in Japan. In total, 76 independent cDNA clones were used for sequencing and phylogenetic analyses. Two major population clusters were identified. The first consisted of all four hop isolates from Akita and some from Yamagata. The second cluster consisted of some Yamagata hop and all apple isolates. On the basis of the polymorphism found in the nucleotide insertion between positions 142/143 of the AFCVd genome and the history of hop cultivation in the region, it appears likely that one of the AFCVd populations that pre-existed in the Yamagata hops served as a "founder" for the Akita hop cluster. In this scenario, a genetic bottleneck caused by vegetative propagation played an important role in the shaping of viroid populations in a cultivated crop.

  7. 利用TOC与基础IE的瓶颈分析与改善%Bottleneck analyzing and improvement based on the theory of constraints

    Institute of Scientific and Technical Information of China (English)

    周驰; 邓富民

    2011-01-01

    Briefly introduce the Theory of Constraints(TOC), take TG workshop for example, apply TOC combined with industrial engineering technologies such as time study ,human-machine chart and process improvement to find, analyze, improve and finally break the bottleneck, raise the effective output.%简要介绍约束理论(Theory of Constraints,TOC),以某企业TC车间为例,根据TOC的具体思路,结合秒表时间研究、人机图和工艺改善等工业工程技术,发现瓶颈制约因素,并对瓶颈制约因素进行分析与改善,最终打破瓶颈,提高了有效产出.

  8. 智能终端续航瓶颈分析与解决方案%Analysis on Battery Life Bottleneck of Smart Terminal and its Solution

    Institute of Scientific and Technical Information of China (English)

    王朝晖; 程贵锋

    2015-01-01

    分析了智能终端续航瓶颈产生的原因,从芯片、器件、软硬件优化等方面剖析了提升智能手机、可穿戴及IoT终端续航能力的优化提升方向与解决方案,并对智能终端续航体验的发展前景作出了预判。%The cause of battery life bottleneck of smart terminal was analyzed in this paper. From aspects of chip, component, software & hardware optimization, the optimization direction and solution to promote battery life of smart phone, wearable device and IoT terminal were discussed. The developmental perspective of battery life experience of smart terminal was presented.

  9. Retrospective analyses of the bottleneck in purification of eukaryotic proteins from Escherichia coli as affected by molecular weight, cysteine content and isoelectric point.

    Science.gov (United States)

    Jeon, Won Bae

    2010-05-01

    Experimental bioinformatics data obtained from an E. coli cell-based eukaryotic protein purification experiment were analyzed in order to identify any bottleneck as well as the factors affecting the target purification. All targets were expressed as His-tagged maltose-binding protein (MBP) fusion constructs and were initially purified by immobilized metal affinity chromatography (IMAC). The targets were subsequently separated from the His-tagged MBP through TEV protease cleavage followed by a second IMAC isolation. Of the 743 total purification trials, 342 yielded more than 3 mg of target proteins for structural studies. The major reason for failure of target purification was poor TEV proteolysis. The overall success rate for target purification decreased linearly as cysteine content or isoelectric point (pI) of the target increased. This pattern of pI versus overall success rate strongly suggests that pI should be incorporated into target scoring criteria with a threshold value.

  10. Population-based resequencing analysis of wild and cultivated barley revealed weak domestication signal of selection and bottleneck in the Rrs2 scald resistance gene region.

    Science.gov (United States)

    Fu, Yong-Bi

    2012-02-01

    Many plant disease resistance (R) genes have been cloned, but the potential of utilizing these plant R-gene genomic resources for genetic inferences of plant domestication history remains unexplored. A population-based resequencing analysis of the genomic region near the Rrs2 scald resistance gene was made in 51 accessions of wild and cultivated barley from 41 countries. Fifteen primer pairs were designed to sample the genomic region with a total length of 10 406 bp. More nucleotide diversity was found in wild (π = 0.01846) than cultivated (π = 0.01507) barley samples. Three distinct groups of 29 haplotypes were detected for all 51 samples, and they were well mixed with wild and cultivated barley samples from different countries and regions. The neutrality tests by Tajima's D were not significant, but a significant (P domestication. Together, the domestication signal in the genomic region was weak both in human selection and domestication bottleneck.

  11. Evidence for a response preparation bottleneck during dual-task performance: effect of a startling acoustic stimulus on the psychological refractory period.

    Science.gov (United States)

    Maslovat, Dana; Chua, Romeo; Spencer, Hunter C; Forgaard, Christopher J; Carlsen, Anthony N; Franks, Ian M

    2013-11-01

    The present study was designed to investigate the mechanism associated with dual-task interference in a psychological refractory period (PRP) paradigm. We used a simple reaction time paradigm consisting of a vocal response (R1) and key-lift task (R2) with a stimulus onset asynchrony (SOA) between 100ms and 1500ms. On selected trials we implemented a startling acoustic stimulus concurrent with the second stimulus to determine if we could involuntarily trigger the second response. Our results indicated that the PRP delay in the second response was present for both control and startle trials at short SOAs, suggesting the second response was not prepared in advance. These results support a response preparation bottleneck and can be explained via a neural activation model of preparation. In addition, we found that the reflexive startle activation was reduced in the dual-task condition for all SOAs, a result we attribute to prepulse inhibition associated with dual-task processing.

  12. A comparison of the psychological refractory period and prioritized processing paradigms: Can the response-selection bottleneck model explain them both?

    Science.gov (United States)

    Miller, Jeff; Durst, Moritz

    2015-10-01

    Four experiments examined whether well-established phenomena from the psychological refractory period (PRP) paradigm are also observed in the prioritized processing paradigm, as would be expected from a common description of the 2 paradigms with the response selection bottleneck (RSB) model. Consistent with a generalization of the RSB model to the prioritized processing paradigm, Experiments 1 and 2 showed that this paradigm yields effects of SOA and stimulus discriminability analogous to those observed in the PRP paradigm. In Experiments 3 and 4, however, overall RTs and effect sizes differed between the PRP and prioritized processing paradigms in ways that are difficult to explain within the RSB model. Understanding the differences between these 2 paradigms offers considerable promise as a way to extend the RSB model beyond the domain of the PRP paradigm and to generalize our understanding of multitasking interference.

  13. 高校贫困生资助工作瓶颈探析%Bottleneck analysis of the college poor students' subsidy work

    Institute of Scientific and Technical Information of China (English)

    黄振霞; 林萍萍; 洪丽斯; 蔡煌镇

    2012-01-01

    The college poor students' subsidy work have produced a series of bottleneck problems in the current.Take putian university for example,according to the work of designation,the ways and effect of subsidy,by means of questionnaire survey,data and cause analysis,and then put forward optimization strategy to promote the development of the college poor students' subsidy work.%当前各高校贫困生资助工作产生了一系列瓶颈问题,以莆田学院为采点,对贫困生的认定工作、资助方式、受助效果等方面,通过大量问卷调查和数据分析,探析问题所在,提出优化策略,促进各高校贫困生资助工作的开展。

  14. Enriching the Metadata on CERN Document Server And Implementation of a Book Acquisition System To Predict the potential bottlenecks in availability of records in Library

    CERN Document Server

    Ahuja, Chakshu

    2015-01-01

    The automated script for data acquisition project ( bibtasklet ) which aims to enhance existing metadata in our CERN Document Server with data from Springer was implemented. An implicit part of this task is to manage disambiguation (within incoming data), removal of multiple entries, handle replications between new and existing records and further automate the latest file upload task to CDS. All such elements and their corresponding changes are integrated within Invenio to make the upgraded metadata available on the CDS. Another implementation was to make a web interface for the invenio software to calculate the normalized loan period to help the librarians to predict bottleneck on the books on loan over certain period of time and facilitate their decision to buy the new records accordingly.

  15. Pathways of Lipid Metabolism in Marine Algae, Co-Expression Network, Bottlenecks and Candidate Genes for Enhanced Production of EPA and DHA in Species of Chromista

    Directory of Open Access Journals (Sweden)

    Alice Mühlroth

    2013-11-01

    Full Text Available The importance of n-3 long chain polyunsaturated fatty acids (LC-PUFAs for human health has received more focus the last decades, and the global consumption of n-3 LC-PUFA has increased. Seafood, the natural n-3 LC-PUFA source, is harvested beyond a sustainable capacity, and it is therefore imperative to develop alternative n-3 LC-PUFA sources for both eicosapentaenoic acid (EPA, 20:5n-3 and docosahexaenoic acid (DHA, 22:6n-3. Genera of algae such as Nannochloropsis, Schizochytrium, Isochrysis and Phaedactylum within the kingdom Chromista have received attention due to their ability to produce n-3 LC-PUFAs. Knowledge of LC-PUFA synthesis and its regulation in algae at the molecular level is fragmentary and represents a bottleneck for attempts to enhance the n-3 LC-PUFA levels for industrial production. In the present review, Phaeodactylum tricornutum has been used to exemplify the synthesis and compartmentalization of n-3 LC-PUFAs. Based on recent transcriptome data a co-expression network of 106 genes involved in lipid metabolism has been created. Together with recent molecular biological and metabolic studies, a model pathway for n-3 LC-PUFA synthesis in P. tricornutum has been proposed, and is compared to industrialized species of Chromista. Limitations of the n-3 LC-PUFA synthesis by enzymes such as thioesterases, elongases, acyl-CoA synthetases and acyltransferases are discussed and metabolic bottlenecks are hypothesized such as the supply of the acetyl-CoA and NADPH. A future industrialization will depend on optimization of chemical compositions and increased biomass production, which can be achieved by exploitation of the physiological potential, by selective breeding and by genetic engineering.

  16. Ancient and contemporary DNA reveal a pre-human decline but no population bottleneck associated with recent human persecution in the kea (Nestor notabilis.

    Directory of Open Access Journals (Sweden)

    Nicolas Dussex

    Full Text Available The impact of population bottlenecks is an important factor to consider when assessing species survival. Population declines can considerably limit the evolutionary potential of species and make them more susceptible to stochastic events. New Zealand has a well documented history of decline of endemic avifauna related to human colonization. Here, we investigate the genetic effects of a recent population decline in the endangered kea (Nestor notabilis. Kea have undergone a long-lasting persecution between the late 1800s to 1970s where an estimated 150,000 kea were culled under a governmental bounty scheme. Kea now number 1,000-5,000 individuals in the wild and it is likely that the recent population decline may have reduced the genetic diversity of the species. Comparison of contemporary (n = 410, historical (n = 15 and fossil samples (n = 4 showed a loss of mitochondrial diversity since the end of the last glaciation (Otiran Glacial but no loss of overall genetic diversity associated with the cull. Microsatellite data indicated a recent bottleneck for only one population and a range-wide decline in Ne dating back some 300 - 6,000 years ago, a period predating European arrival in NZ. These results suggest that despite a recent human persecution, kea might have experienced a large population decline before stabilizing in numbers prior to human settlement of New Zealand in response to Holocene changes in habitat distribution. Our study therefore highlights the need to understand the respective effects of climate change and human activities on endangered species dynamics when proposing conservation guidelines.

  17. Genetic Signatures of Demographic Changes in an Avian Top Predator during the Last Century: Bottlenecks and Expansions of the Eurasian Eagle Owl in the Iberian Peninsula.

    Directory of Open Access Journals (Sweden)

    Eva Graciá

    Full Text Available The study of the demographic history of species can help to understand the negative impact of recent population declines in organisms of conservation concern. Here, we use neutral molecular markers to explore the genetic consequences of the recent population decline and posterior recovery of the Eurasian eagle owl (Bubo bubo in the Iberian Peninsula. During the last century, the species was the object of extermination programs, suffering direct persecution by hunters until the 70's. Moreover, during the last decades the eagle owl was severely impacted by increased mortality due to electrocution and the decline of its main prey species, the European rabbit (Oryctolagus cuniculus. In recent times, the decrease of direct persecution and the implementation of some conservation schemes have allowed the species' demographic recovery. Yet, it remains unknown to which extent the past population decline and the later expansion have influenced the current species' pattern of genetic diversity. We used eight microsatellite markers to genotype 235 eagle owls from ten Spanish subpopulations and analyse the presence of genetic signatures attributable to the recent population fluctuations experienced by the species. We found moderate levels of differentiation among the studied subpopulations and Bayesian analyses revealed the existence of three genetic clusters that grouped subpopulations from central, south-western and south-eastern Spain. The observed genetic structure could have resulted from recent human-induced population fragmentation, a patchy distribution of prey populations and/or the philopatric behaviour and habitat selection of the species. We detected an old population bottleneck, which occurred approximately 10,000 years ago, and significant signatures of recent demographic expansions. However, we did not find genetic signatures for a recent bottleneck, which may indicate that population declines were not severe enough to leave detectable signals

  18. Genetic Signatures of Demographic Changes in an Avian Top Predator during the Last Century: Bottlenecks and Expansions of the Eurasian Eagle Owl in the Iberian Peninsula.

    Science.gov (United States)

    Graciá, Eva; Ortego, Joaquín; Godoy, José Antonio; Pérez-García, Juan Manuel; Blanco, Guillermo; Delgado, María del Mar; Penteriani, Vincenzo; Almodóvar, Irene; Botella, Francisco; Sánchez-Zapata, José Antonio

    2015-01-01

    The study of the demographic history of species can help to understand the negative impact of recent population declines in organisms of conservation concern. Here, we use neutral molecular markers to explore the genetic consequences of the recent population decline and posterior recovery of the Eurasian eagle owl (Bubo bubo) in the Iberian Peninsula. During the last century, the species was the object of extermination programs, suffering direct persecution by hunters until the 70's. Moreover, during the last decades the eagle owl was severely impacted by increased mortality due to electrocution and the decline of its main prey species, the European rabbit (Oryctolagus cuniculus). In recent times, the decrease of direct persecution and the implementation of some conservation schemes have allowed the species' demographic recovery. Yet, it remains unknown to which extent the past population decline and the later expansion have influenced the current species' pattern of genetic diversity. We used eight microsatellite markers to genotype 235 eagle owls from ten Spanish subpopulations and analyse the presence of genetic signatures attributable to the recent population fluctuations experienced by the species. We found moderate levels of differentiation among the studied subpopulations and Bayesian analyses revealed the existence of three genetic clusters that grouped subpopulations from central, south-western and south-eastern Spain. The observed genetic structure could have resulted from recent human-induced population fragmentation, a patchy distribution of prey populations and/or the philopatric behaviour and habitat selection of the species. We detected an old population bottleneck, which occurred approximately 10,000 years ago, and significant signatures of recent demographic expansions. However, we did not find genetic signatures for a recent bottleneck, which may indicate that population declines were not severe enough to leave detectable signals on the species

  19. 基于TOC和OTE的生产瓶颈识别与优化%Optimization and detection of bottleneck in production based on TOC and OTE

    Institute of Scientific and Technical Information of China (English)

    於骞; 金士良; 何文中

    2011-01-01

    TOC思想即约束理论是平衡生产线的一个重要工具,它告诉我们可以通过查询瓶颈以及经过利用资源消除瓶颈来达到生产线平衡;而OTE是生产线产能的一种量化指标,而这种生产线指的是具有多台设备联系在一起的生产流程.在介绍TOC思想和OTE计算公式的基础上,利用Witness仿真软件对生产系统建模与仿真,结合TOC和OTE来识别在不同需求下的生产系统瓶颈,提出解决瓶颈的优化方案,改进生产系统,在考虑成本的情况下增加整个系统合格产出,以及提高整个系统的产能.%TOC is a important tool for making the production line balance,we can use TOC to find bottleneck and undo the it by every resource we have ;OTE is metric for capacity of line which has many series machines.With the idea of TOC and the calculation of OTE, It will put forward modeling and simulat-ing of manufacturing system by using witness,detecting bottleneck in line on different market demand, proposing the optimal solution and improving the system in enhancing the qualified output as will as pro-duction capacity in considering cost which are all based on combination of TOC and OTE.

  20. 瓶颈链路队列长度的网络认知模型%Network Cognitive Model of Bottleneck Link Queue Length

    Institute of Scientific and Technical Information of China (English)

    赵淼; 王辉

    2012-01-01

    为解决传统传输控制协议(TCP)在异构网络中效率较低的问题,给出网络状态认知的定义,建立以瓶颈链路队列长度为目标量的网络认知模型,采用TCP-L传输控制协议进行仿真.实验结果证明,该模型能准确估计瓶颈链路队列长度的动态变化趋势.TCP-L协议能在不同负荷的背景流条件下稳定发送窗口、往返传输时延和队列长度,减少拥塞发生,提高吞吐量和传输效率.%In view bf the traditional Transmission Control Protocol(TCP) control protocol efficiency in heterogeneous network, this paper gives the definition of the cognition of the network status, proposes and constructs a network cognitive model which makes the length of bottleneck link queue as the target parameter. This model uses TCP-L transmission control protocol to finish simulation experiments. Experimental result shows that this model can more accurately estimate the dynamic change trend of bottleneck link queue's length, and its estimate can be more accurately located in the gathering area of true values. Under different background flow conditions, the TCP-L protocol can stabilize sending window, round trip transmission delay and queue length, reduce congestion and improve throughput and transmission efficiency.

  1. 光网络中基于瓶颈链路优先的升级策略%The Strategy of Bottleneck Links Upgrade First in Optical Networks

    Institute of Scientific and Technical Information of China (English)

    黄冲; 刘逢清

    2016-01-01

    In order to solve the inefficient spectrum utilization problem in fixed-grid WDM networks,an upgrading scheme is proposed to upgrade the bottleneck links from fixed grid to flex grid networks.The paper defines the concept of bottleneck links,and proposes two strategies:the Link Density(LD)strategy and the congestion strategy.Numerical results show that the Bandwidth Blocking Rate (BBR)is reduced by the two strategies.The LD strategy performs different BBR reduction de-pending on different thresholds and the congestion strategy can effectively reduce the BBR.%针对固定栅格 WDM(波分复用)光网络频谱利用率低的缺点,需对网络使用灵活栅格技术进行升级,提出了基于瓶颈链路优先的升级策略。文章定义了瓶颈链路,提出两种基于瓶颈链路的升级策略:链路密度策略和拥塞链路策略,并对这两种策略进行仿真,仿真结果显示两种策略都能够降低带宽阻塞率。链路密度策略的带宽阻塞率降低程度取决于所取阈值的不同,而拥塞链路策略能有效地降低带宽阻塞率。

  2. Correction: Forrester, N.L.; Coffey, L.L.; Weaver, S.C. Arboviral Bottlenecks and Challenges to Maintaining Diversity and Fitness during Mosquito Transmission. Viruses 2014, 6, 3991–4004

    Directory of Open Access Journals (Sweden)

    Naomi L. Forrester

    2014-11-01

    Full Text Available In the original manuscript, Forrester, N.L.; Coffey, L.L.; Weaver, S.C. Arboviral Bottlenecks and Challenges to Maintaining Diversity and Fitness during Mosquito Transmission. Viruses 2014, 6, 3991–4004, Figure 1 contains an error, the third bottle was absent from the figure:[...

  3. Empirical Study for Improving the Traffic Conditions at Bottleneck Road Sections%瓶颈路段交通改善实证研究

    Institute of Scientific and Technical Information of China (English)

    李妙君; 孙全欣; 杨静

    2011-01-01

    城市道路路网中,瓶颈路段的存在对路网通行能力有显著的影响.本文归纳了瓶颈路段存在的两类常见问题:由于拆迁、开发遗留等造成的瓶颈路拥堵;以及铁路、桥等阻碍造成的瓶颈路拥堵.对断头路、瓶颈路的改善措施进行了梳理.结合姚家园路区域-朝阳公园桥案例展开了实证研究,研究表明,断头路的存在对路网的通达性有明显影响;合理调节支路的分流量,可以减轻路网节点的拥堵程度;打通断头路,路网的非直线系数提高,更加方便路网中节点的交流;畸形交叉口的改善,使路网的连接度提高17.5%.%The road sections as bottlenecks of a road network decrease the traffic capacity of the road network significantly.The reasons for making bottleneck road sections are summarized in this study.They include the bad planning of the urban roads in the process of urban development and the influence from the railway lines and bridges in the urban areas.Based on the study of the Chaoyang Park Bridge around Yaojiayuan Road, it is proved that break road sections have a significant impact on the capacity of the road network and sharing part of the traffic volume on arterial roads to branch roads can release the congestion level at the nodes the road network.Smoothing break road sections can increase the value of the non-linear coefficient of the road network and make the connections between the nodes of the road network more easily.Moreover, improving the traffic conditions at intersections whose configurations are irregular can increase the accessibility of the road network by 17.5%.

  4. Genetic Variability of Bovine Viral Diarrhea Virus and Evidence for a Possible Genetic Bottleneck during Vertical Transmission in Persistently Infected Cattle.

    Directory of Open Access Journals (Sweden)

    Natalie Dow

    Full Text Available Bovine viral diarrhea virus (BVDV, a Pestivirus in the family Flaviviridae, is an economically important pathogen of cattle worldwide. The primary propagators of the virus are immunotolerant persistently infected (PI cattle, which shed large quantities of virus throughout life. Despite the absence of an acquired immunity against BVDV in these PI cattle there are strong indications of viral variability that are of clinical and epidemiological importance. In this study the variability of E2 and NS5B sequences in multiple body compartments of PI cattle were characterized using clonal sequencing. Phylogenetic analyses revealed that BVDV exists as a quasispecies within PI cattle. Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir. We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring. These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

  5. Genetic Variability of Bovine Viral Diarrhea Virus and Evidence for a Possible Genetic Bottleneck during Vertical Transmission in Persistently Infected Cattle.

    Science.gov (United States)

    Dow, Natalie; Chernick, Adam; Orsel, Karin; van Marle, Guido; van der Meer, Frank

    2015-01-01

    Bovine viral diarrhea virus (BVDV), a Pestivirus in the family Flaviviridae, is an economically important pathogen of cattle worldwide. The primary propagators of the virus are immunotolerant persistently infected (PI) cattle, which shed large quantities of virus throughout life. Despite the absence of an acquired immunity against BVDV in these PI cattle there are strong indications of viral variability that are of clinical and epidemiological importance. In this study the variability of E2 and NS5B sequences in multiple body compartments of PI cattle were characterized using clonal sequencing. Phylogenetic analyses revealed that BVDV exists as a quasispecies within PI cattle. Viral variants were clustered by tissue compartment significantly more often than expected by chance alone with the central nervous system appearing to be a particularly important viral reservoir. We also found strong indications for a genetic bottleneck during vertical transmission from PI animals to their offspring. These quasispecies analyses within PI cattle exemplify the role of the PI host in viral propagation and highlight the complex dynamics of BVDV pathogenesis, transmission and evolution.

  6. The Mouse-colored Tyrannulet (Phaeomyias murina) is a species complex that includes the Cocos Flycatcher (Nesotriccus ridgwayi), an island form that underwent a population bottleneck.

    Science.gov (United States)

    Zucker, Marc R; Harvey, Michael G; Oswald, Jessica A; Cuervo, Andrés; Derryberry, Elizabeth; Brumfield, Robb T

    2016-08-01

    Simultaneous examination of evolutionary history in island forms and closely related mainland relatives can provide reciprocal insight into the evolution of island and mainland faunas. The Cocos Flycatcher (Nesotriccus ridgwayi) is a small tyrant flycatcher (Tyrannidae) endemic to Cocos Island, an oceanic island in the eastern Pacific Ocean. We first established its close relationship to the mainland species Mouse-colored Tyrannulet (Phaeomyias murina) using a phylogeny from genome-wide ultraconserved elements and exons. We then used mitochondrial DNA to explore the relationships between Nesotriccus and Phaeomyias populations from across its distribution in Central and South America. We found that Nesotriccus is nested within the Phaeomyias evolutionary tree, and that Phaeomyias represents a complex of at least four evolutionarily distinct species that differ in plumage, voice, and habitat association. Nesotriccus underwent a population bottleneck subsequent to its divergence from Central American and northern South American Phaeomyias populations in the middle Pleistocene. The 46 UCE loci containing alleles that are fixed between the two species are widely distributed across the genome, which suggests that selective or neutral processes responsible for divergence have occurred genome-wide. Overall, our simultaneous examination of Phaeomyias and Nesotriccus revealed divergent levels of genetic diversity and evolutionary histories between island and mainland forms.

  7. Method and Application of Manufacturing Industry Breaking Inventory Management Bottleneck%制造业突破库存管理瓶颈的方法及应用

    Institute of Scientific and Technical Information of China (English)

    董鹏; 郭丽美; 荆一帆

    2013-01-01

    The authors analyse the bottleneck of traditional inventory management and relative view points of inven-tory management, and find out the reason of inventory backlog of Carlisle company finished products and its bad in-fluence on enterprises. Combined with the example of Carlisle company to reduce the inventory backlog, they point out that the application of management tools, such as objectives management, fishbone diagram, ABC classification, is the most effective method to reduce the inventory backlog. This can provide reference to related manufacturing in-dustry for effective inventory management.%  分析传统库存管理的瓶颈及库存管理的相关观点,找出卡莱公司造成成品库存积压的原因及带来的不良影响;结合卡莱公司降低库存的实例,指出运用目标管理、鱼骨图、ABC分类等管理工具,是降低库存的最有效方法,为相关制造业进行有效的库存管理提供借鉴。

  8. The Pricing Theory and Modelsin a High Way with Bottleneck%瓶颈道路使用收费理论及模型

    Institute of Scientific and Technical Information of China (English)

    王丽佳

    2014-01-01

    拥挤道路使用收费作为现代城市交通需求管理的有效措施在理论上和实践上都具有十分重要的意义。文中以经典瓶颈模型为基础,首先在固定用户情况下讨论了不收费平衡;进而讨论了用户有需求,容量任意情况下的不收费平衡和收费平衡;最后讨论了用户有需求,容量最优情况下的收费平衡和不收费平衡,这对进一步研究道路使用收费有一定的借鉴意义。%Congested roads using charge as the effective measures of modern urban traffic demand management in theory and practice is of great significance .On the basis of the classical bottleneck model ,this paper first discussed under the condition of fixed users don't charge balance.And then discusses the user demand ,capacity of any circumstances not charge balance and balance.Finally discusses the users demand ,capacity,the optimal conditions of charge balance and no charge ,balance,All of these have certain reference significance .

  9. 基于时空检测的城市交通网络瓶颈识别方法研究%Urban traffic network bottleneck identification based on temporal and spatial detection

    Institute of Scientific and Technical Information of China (English)

    丁恒; 郭放; 郑小燕; 马寒月; 张卫华

    2016-01-01

    In order to solve the problem of bottleneck identification in congested traffic network ,the road node and link were analyzed based on temporal and spatial detection data ,and then the urban traffic network bottleneck identification and classification model was established .Taking the interval of any two floating cars continuously through each intersection of congestion path as statistical time and the rate of outflow corresponding to each intersection of congestion path as statistical object ,the traffic sequence when many floating cars were passing through was continuously statisticalized .Then the intersection correlation model was established to divide the traffic network bottleneck .Taking the divided area of traffic bottleneck as a closed area ,through analyzing the inflow and outflow rate during the period of congestion and flat peak ,and using the Chebyshev’s inequality under the condition of a 95% confidence level ,three types of congestion bottleneck were established ,namely imported bottle‐neck ,outputted bottleneck and passed bottleneck .Taking the actual regional road network as analysis object ,the congestion area was analyzed by using the above model .The results show that the model can effectively identify and classify the traffic network bottleneck .%为了解决拥堵状态下交通网络瓶颈识别问题,文章基于时空检测数据对道路节点和路段拥堵状态进行了分析,并以此为基础建立了城市交通网络瓶颈识别与分类模型。拥堵发生期间,以任意2辆浮动车连续通过拥堵路径各个交叉口时间间隔作为统计时间,以拥堵路径各个交叉口对应流向流出率作为统计对象,连续统计多辆浮动车通过时的交通量序列,建立了拥堵路径交叉口关联度模型并以此划分交通网络瓶颈。以划分的交通拥堵瓶颈区域作为密闭区域,通过分析拥堵路径平峰期间与拥堵期间的流入流出率,使用切

  10. Time-varying Material Distribution Routing Optimization Considering Shifting Bottleneck%计及漂移瓶颈的时变物料配送路径优化

    Institute of Scientific and Technical Information of China (English)

    凌琳; 刘明周; 葛茂根; 王强; 马靖

    2015-01-01

    Aiming at the material distribution routing optimization problem under uncertain job shop environment, the bottleneck index and bottleneck shifting index which represent the relative production load of each manufacturing unit and its the change trend are adopted to denote the time-varying distribution priority of the manufacturing unit. Then the time-varying material distribution routing optimization models are established and its objective is minimizing the distribution cost including vehicle transportation cost and punishment cost due to the violation of distribution priority. Based on that, suppose the condition that the vehicle haven't to be loaded fully and material can be distributed to one manufacturing more times in order to guarantee that the material in the vehicle is distributed totally before the vehicle comes back to the distribution center and to avoid unnecessary distribution sub-route, then propose the modified time-varying material distribution routing optimization model to enhance the distribution productivity and decrease the distribution cost further. The greedy-based genetic algorithm is presented to solve the proposed optimization model. An example of some job shop material distribution routing optimization is given to prove the validation and practicability of the proposed method under uncertainty.%针对不确定作业车间环境下物料配送路径优化问题,采用能反映制造单元相对生产负荷及其变化趋势的瓶颈指数和瓶颈漂移指数表征实时变化的制造单元物料配送优先级,对路径选择过程中违反此优先级的行为设置惩罚成本,提出以最小化包括车辆运输成本和违反优先级的惩罚成本在内的总配送成本为优化目标,建立了时变的物料配送路径优化模型.在此基础上,为保证运输车辆所载物料全额配送,避免非必要负载以及由此造成的非必要配送子路径,对配送路径优化模型进行改进,允许运输车辆非满载和

  11. Study on due-time bottleneck identification in job shop based on fuzzy inference system%基于模糊推理系统的作业车间交货期瓶颈辨识研究

    Institute of Scientific and Technical Information of China (English)

    顾余容; 鲁建厦; 詹燕

    2011-01-01

    Aiming at the rising problem of poor due-time satisfaction in current manufacturing industry, the importance and urgency of the study on due-time bottleneck is described. A fuzzy inference system is employed to define due-time bottleneck. The identification method of due-time bottleneck job in different processing stage is proposed and the identification model of due-time bottleneck in job shop is established. The identification method based on fuzzy inference system is convenient to be practically applied and also suitable to be employed to simulate by computer software. The example concerning a workshop proves the feasibility of the model and method.%针对现今制造企业的客户交货期满意度低的问题,阐述了研究交货期瓶颈问题的重要性和紧迫性.通过应用模糊推理系统知识来定义交货期瓶颈,提出了辨识不同加工阶段的交货期瓶颈工件的方法,建立了作业车间生产系统的交货期瓶颈辨识模型.基于模糊推理系统的辨识方法操作方便,便于用计算机软件实现.最后,应用某加工车间的实例说明了该辨识方法的有效性.

  12. 基于定点数据的道路瓶颈拥挤自动识别算法%Automatic Identification Algorithm for Road Bottlenecks Based on Detector Data

    Institute of Scientific and Technical Information of China (English)

    弓晋丽; 彭贤武

    2013-01-01

    为研究道路瓶颈处的交通拥挤现象,掌握由道路瓶颈引发的常发性拥挤的分布特点和变化规律,提出了道路瓶颈拥挤的自动识别算法.基于检测线圈历史数据,将交通状态定性划分为畅通和拥挤2种,根据瓶颈拥挤原理,识别道路瓶颈所在,并同时对由其引发的拥挤持续时长和拥挤范围进行鉴别.算法运算结果包含瓶颈定位及由其引发的拥挤持续时长和空间影响范围.以上海市南北高架路东侧10 d线圈检测数据为例,验证了算法的有效性和实用性.%To study the problem of traffic congestion at road bottlenecks and know the distribution properties as to change regulation of the Recurrent Congestion, a new automatic identification algorithm for road bottlenecks was proposed. Based on historical traffic data from the dual-loop detectors on road, the algorithm differentiates uncongested traffic state from congested state, thereby identifying traffic bottlenecks according to principle of congestion. It will also compute the congestion duration and influence range caused by bottlenecks at the same time. By using field data from dual-loop detectors on Shanghai North-South elevated road for 10 days, the effectiveness and practicality of the algorithm have been verified.

  13. The formation of catalytically competent enzyme-substrate complex is not a bottleneck in lesion excision by human alkyladenine DNA glycosylase.

    Science.gov (United States)

    Kuznetsov, N A; Kiryutin, A S; Kuznetsova, A A; Panov, M S; Barsukova, M O; Yurkovskaya, A V; Fedorova, O S

    2017-04-01

    Human alkyladenine DNA glycosylase (AAG) protects DNA from alkylated and deaminated purine lesions. AAG flips out the damaged nucleotide from the double helix of DNA and catalyzes the hydrolysis of the N-glycosidic bond to release the damaged base. To understand better, how the step of nucleotide eversion influences the overall catalytic process, we performed a pre-steady-state kinetic analysis of AAG interaction with specific DNA-substrates, 13-base pair duplexes containing in the 7th position 1-N6-ethenoadenine (εA), hypoxanthine (Hx), and the stable product analogue tetrahydrofuran (F). The combination of the fluorescence of tryptophan, 2-aminopurine, and 1-N6-ethenoadenine was used to record conformational changes of the enzyme and DNA during the processes of DNA lesion recognition, damaged base eversion, excision of the N-glycosidic bond, and product release. The thermal stability of the duplexes characterized by the temperature of melting, Tm, and the rates of spontaneous opening of individual nucleotide base pairs were determined by NMR spectroscopy. The data show that the relative thermal stability of duplexes containing a particular base pair in position 7, (Tm(F/T) < Tm(εA/T) < Tm(Hx/T) < Tm(A/T)) correlates with the rate of reversible spontaneous opening of the base pair. However, in contrast to that, the catalytic lesion excision rate is two orders of magnitude higher for Hx-containing substrates than for substrates containing εA, proving that catalytic activity is not correlated with the stability of the damaged base pair. Our study reveals that the formation of the catalytically competent enzyme-substrate complex is not the bottleneck controlling the catalytic activity of AAG.

  14. Phylogeography of postglacial range expansion in Juglans mandshurica (Juglandaceae) reveals no evidence of bottleneck, loss of genetic diversity, or isolation by distance in the leading-edge populations.

    Science.gov (United States)

    Wang, Wen-Ting; Xu, Bing; Zhang, Da-Yong; Bai, Wei-Ning

    2016-09-01

    The past studies of postglacial recolonization patterns in high latitude regions have revealed a significant role of dispersal capacity in shaping the genetic diversity and population structure of temperate trees. However, most of these studies have focused on species with long-distance dispersal followed by exponential population growth and were therefore unable to reveal the patterns in the case of a gradual expansion. Here we studied the impacts of postglacial range expansions on the distribution of genetic diversity in the Manchurian walnut (Juglans mandshurica), a common tree of East Asian cool-temperate deciduous forests that apparently lacks long-distance seed dispersal ability. The genetic diversity and structure of 19 natural walnut populations in Northeast China and the Korean Peninsula were examined using 17 nuclear simple sequence repeat (SSR) loci. Potential habitats under current and past climatic conditions were predicted using the ecological niche modelling (ENM) method. Bayesian clustering analysis revealed three groups, which were inferred to have diverged through multiple glacial-interglacial cycles in multiple refugia during the Quaternary Period. ENM estimated a southward range shift at the LGM, but high suitability scores still occurred in the western parts of the Changbai Mountains (Northeast China), the Korean peninsula and the exposed seafloor of the Yellow Sea. In contrast to most other cool-temperate trees co-occurring in the same region, the Manchurian walnut did not show any evidence of a population bottleneck, loss of genetic diversity or isolation by distance during the postglacial expansion. Our study clearly indicates that current northern populations originated from one glacial lineage and recolonization via a gradually advancing front due to the lack of a long-distance seed dispersal mechanism led to no latitudinal decrease in genetic diversity.

  15. 社区老年教育发展的瓶颈与对策﹡%Bottleneck and Countermeasures of Community Geriatric Education Development

    Institute of Scientific and Technical Information of China (English)

    乔维德

    2015-01-01

    目前,我国基层社区老年教育面临着发展的瓶颈。其原因主要有社区老年教育覆盖面窄、实际参与率低、资源匮乏、教育内容形式单一、资金投入不足、师资力量匮乏等因素。要加快发展社区老年教育,应着力创新健全管理机制,改善社区老年教育的办学条件,培育社区老年教育专业队伍,合理设置社区老年教育课程,推广社区老年教育的数字化学习。%Recently, there are many bottlenecks in the development of elderly education, especially in elderly education of the grass-roots community. This essay takes Wuxi as a case to explore its reasons, which mainly are the community elderly education narrow coverage, low actual participation, the lack of resources, form a single, underfunded education content, the lack of teachers and other factors. To speed up the development of community elderly education, we should focus on innovation and perfect management mechanism, improve the conditions of elderly community education and foster community geriatric education professional team, setting up reasonable community education courses, to promote community geriatric education digital learning.

  16. 发展大学生领导力教育的瓶颈及对策%The Bottlenecks and Countermeasures on the Leadership Education of College Students

    Institute of Scientific and Technical Information of China (English)

    张恒龙; 张书磊

    2012-01-01

    世界各国的经验表明,高校开展大学生领导力教育有利于大学生更好地适应未来不断变化发展的现代社会。近些年,我国也开始关注大学生领导力教育问题,但在发展大学生领导力教育过程中存在定位有失偏颇、理解不够全面、教育资源的开发与利用不足等三大瓶颈。为此,对大学生领导力教育进行恰当定位,从大学生成长成才的角度出发开展领导力教育。探索大学生领导力教育长效机制显得十分紧迫和必要。%The experience of leadership education for college students around the world shows that it's helpful for them to better adapt to the changing modem society. Recently more and more universities have launched some projects of leadership education for college students in China, but in the process there are three bottlenecks. One is that many people haven't realized the importance of leadership education for college students; the second is that people haven't fully understood the conception; the third is that the form of leadership education is not rich. Therefore, we should correct the position of leadership education for coil perspective of comprehensive development, and explore the education. lasting ege students, develop leadership from the effect mechanism of student leadership education.

  17. 突破初中英语写作瓶颈的策略分析%Strategies to Break the Bottleneck of Junior High School English Writing

    Institute of Scientific and Technical Information of China (English)

    邓剑昆

    2014-01-01

    English learning includes listening, speaking, reading and writing four parts, in junior high school English teach-ing, teaching writing is an important and indispensable component. The vocabulary of English composition, structure, gram-mar, etc. in one set, writing instruction can promote students' comprehensive ability to use language. However, the current situation is not optimistic teaching junior high school English writing;students learn English writing is not only weak link, but also one of the bottlenecks in the teaching of English teachers. Therefore, this article is for junior high school English Writing discuss the problems in the analysis, put forward some writing teaching measures to improve the quality of teaching and promoting junior high school English writing skills.%英语学习包括了听、说、读、写四个部分,在初中英语教学中,写作教学是不可缺少的重要组成部分。英语作文将词汇、结构、语法等集于一体,写作教学能够促进学生综合语言运用能力。但是,初中英语写作教学现状不容乐观,英语写作不仅是学生学习的薄弱环节,同时也是英语教师在教学中的瓶颈之一。因此,本文就针对初中英语写作教学中存在的问题进行探讨分析,提出了一些写作教学措施,从而提高教学质量,促进初中生英语写作水平。

  18. Progress and Yield Bottleneck of Aerobic Rice in the North China Plain: A Case Study of Varieties Handao 297 and Handao 502

    Institute of Scientific and Technical Information of China (English)

    XIE Guang-hui; YU Jun; WANG Hua-qi; BAM Bouman

    2008-01-01

    Aerobic rice has been considered a promising rice cultivation system as water scarcity is increasing in the world. This article summarizes the advances in aerobic rice management researches in the North China Plain, focusing on yield formation and its bottleneck. High-yielding and good-quality aerobic rice varieties adapted to aerobic soil conditions have been released officially and adopted by farmers in North China. The varieties Handao 502 and Handao 297 have been recognized as the most promising varieties reaching a yield level ranging 3.5-5.0t ha-1 with 450-650mm water input. Compared with lowland rice, water input in aerobic rice was more than 50% lower, and water productivity was 60% higher. Researches on responses of rice cultivars to nitrate nitrogen (N) and ammonium N supplied at early growth stages provided the first evidence for a preference of aerobic rice HD 297 for nitrate N supply, compared with the lowland rice variety. Zinc uptake studies demonstrated that introduction of aerobic rice system on calcareous soils may increase zinc deficiency problems. Sink size was identified as the limitation of aerobic rice yield, because its spikelet number m-2 was too low (20000-24000) compared with the lowland rice. For future research, more attention is suggested to be paid to yield formation focusing on effects of water regimes on tiller dynamics. Understanding of nutrient uptake and response to fertilization effects are also urgently required to establish optimized crop management technology. Additionally, alternative cropping systems based on aerobic rice should be established, and key sustainability and environmental impact issues in the systems need to be identified.

  19. Bottlenecks aggravate rising construction costs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-05-15

    Rising demand for power in developing countries combined with concerns about carbon emissions from coal-fired power plants in developed countries have created a bonanza for carbon-light technologies, including nuclear, renewables and natural gas plants. This, in turn, has put upward pressure on the price of natural gas in key markets while resulting in shortages in critical components for building renewables and nuclear reactors. Globalization of the power industry means that pressures in one segment or one region translate into shortages and rising prices everywhere else.

  20. Distribution Bottlenecks in Classification Algorithms

    NARCIS (Netherlands)

    Zwartjes, G.J.; Havinga, P.J.M.; Smit, G.J.M.; Hurink, J.L.

    2012-01-01

    The abundance of data available on Wireless Sensor Networks makes online processing necessary. In industrial applications for example, the correct operation of equipment can be the point of interest while raw sampled data is of minor importance. Classification algorithms can be used to make state cla

  1. Pompen zijn vaak de bottleneck

    NARCIS (Netherlands)

    Wit-Blok, M. de

    2014-01-01

    Leon Geers, senior research scientist bij TNO Process & Instrumentation Development: “Met het verbeteren van de beheersbaarheid en efficiëntie van de processen zijn er nieuwe ‘zwakste schakels’ ontstaan. Eén daarvan vormen pompen.

  2. A Screening Method for Passenger Flow Bottleneck in Rail Transit Station Based on Reverse Search%基于逆向搜索的轨道交通车站客流瓶颈筛选方法研究

    Institute of Scientific and Technical Information of China (English)

    夏荷香; 刘尔辉

    2015-01-01

    在城市轨道交通客流量急剧增加的同时,城市轨道交通车站的相关设施设备也暴露了严重的集散能力瓶颈问题。为了研究以设施疏散能力为基础的静态瓶颈识别方法,改善轨道交通车站客流组织方案内容,结合通行能力的理论计算方法,提出了一种基于逆向搜索筛选出车站客流瓶颈的方法:通过模拟乘客在车站的走行路径,结合各设备及通道等部位的通行能力,运用逆推的方法来找到车站疏散体系的瓶颈节点。最后,根据广州地铁三号线市桥站的车站空间结构和设施最大通行能力,进行了算法的实际应用。结果表明,该车站的客流瓶颈与实际观测的可能拥堵点相吻合,验证了方法的可用性和有效性。%While passenger traffic flow of urban rail transit increased dramatically, the related facilities and equipment of rail transit stations also emerged the serious bottleneck of distributed capacity. In or⁃der to study the static bottleneck identification method based on the evacuation ability of rail transit facil⁃ities and improve the organization program of passenger flow in rail transit station, a screening method for passenger flow bottleneck in rail transit station based on the reverse search was proposed combined with the theoretical calculation of traffic capacity. By simulating passengers′travelling routes in rail tran⁃sit station and considering the traffic capacity of the channel and equipment, the bottleneck nodes of sta⁃tion evacuation system could be found using the reverse method. Finally, the method was applied in actu⁃al according to the station space structures and facilities maximum traffic capacity of Shiqiao Station in Guangzhou Metro Line Three. The results show that the passenger flow bottlenecks coincide with the po⁃tential congestion points by actual observation. The availability and effectiveness of the method have been verified.

  3. Bottleneck Effect Analysis of Five Pony Populations in China%中国5个矮马品种的瓶颈效应分析

    Institute of Scientific and Technical Information of China (English)

    杨胜林; 徐龙鑫; 杨海兵; 李爱萍

    2013-01-01

    利用13个微卫星基因座对中国5个矮马品种(德保、贵州、宁强、四川、云南)群体进行了遗传平衡检测.根据微卫星等位基因频率,应用无限等位基因模型(infinite allele model,IAM)、双相突变模型(two-phased model of mutation,TPM)和逐步突变模型(step-wise mutation model,SMM)3种模型,符号和Wilcoxon符号—秩2种检验方法,对5个矮马群体的突变—漂移平衡进行分析.结果表明,在IAM下,Wilcoxon符号—秩检验中,德保矮马和云南矮马达到了显著性水平(P<0.05);在SMM下,宁强矮马在符号检验中达到了显著水平(P<0.05);在TPM下,5个群体均未达到显著水平(P>0.05).因此,德保、云南和宁强矮马近期可能经历了瓶颈效应.本研究结果对中国矮马的保护和利用具有重大意义.%Thirteen microsatellite loci were used to analyze genetic equilibrium of five pony populations in China (Debao, Guizhou, Ningqiang, Sichuan, Yunnan). According to the allele frequency, under IAM, TPM and SMM three models, the sign test and Wilcoxon sign-rank test were used to analyze bottleneck of five pony populations. The results showed that Debao and Yunnan pony were observed in the significant level under IAM and Wilcoxon sign-rank test(P0. 05). The results revealed significant level suggesting possible cryptic demographic in Debao, Yunnan and Ningqiang pony. The exploit and conservation priorities about pony populations in China were determined according to the result of the present study.

  4. Signal Control Strategies for Bottleneck Area on Urban Expressway%城市快速路瓶颈区域控制策略研究

    Institute of Scientific and Technical Information of China (English)

    尹胜超; 许润民; 张毅; 李志恒

    2012-01-01

    Urban expressways in China have special features. Distance between on-ramp and off-ramp is relatively shorter compared with tins that in developed countries ( normally longer than 1000 m) , off-ramps are usually connected with urban streets and intersections. Thus successful ramp control strategies used in Europe or U.S. may not be suitable in China. First, this paper studies traffic flow characteristics at several representative "bottlenecks" in Beijing urban expressways. Efforts are devoted to improve the capability of traffic simulation platform to simulate detailed traffic behaviours by calibrating simulation model parameters. Efficiencies of different signal control strategies in road network involving on-ramp, off-ramp, adjacent streets and intersections are compared. Results indicate that combing adaptive ramp control with Synchronization signal control strategies is an efficient way to enhance road capacity and alleviate congestions for urban expressways.%中国的城市快速路与发达国家相比有着截然不同的特征.中国城市快速路匝道出入口之间距离相对较短,且城市快速路匝道出口经常与城市道路交叉口相连,因此在欧美成功应用的快速路匝道控制方案不一定适用于中国.本文详细描述了如何在仿真中设置模型参数,使得城市快速路交通流特性仿真结果与实际测量值具有较高的匹配精度.在具体阐述自适应与协同信号控制策略的基础之上,给出了各种方案在匝道入口、出口辅路和出口下游交叉口的具体部署方案.最终仿真结果表明,自适应和协同控制策略能够提高瓶颈区域道路通行能力8% -9%,有效地缓解城市快速路交通拥堵.

  5. 基于增长修剪型神经网络的半导体生产线动态瓶颈分析方法%Dyna mic Bottleneck Analysis for Se miconductor Wafer Fabrication Syste m Based on Growing and Pru ning Neu ral Networks

    Institute of Scientific and Technical Information of China (English)

    曹政才; 邱明辉; 刘民

    2016-01-01

    Bottleneck is the key factor to semiconductor wafer fabrication system (SWFS),which seriously influ-ences the level of work-in-process,cycle time,time-delivery rate,etc.Efficient analysis for the bottleneck of SWFS can pro-mote various performances.In modern SWFS,present analysis methods usually regard bottleneck device as static bottleneck without taking bottleneck shifting into consideration in the uncertain environment,which leads to scheduling algorithm that always treat the bottleneck device as the core lack of flexibility and real-time performance.Therefore,dynamic bottleneck a-nalysis method for the SWFS based on growing and pruning neural networks (GPNN)was adopted in this study to acquire the dynamic bottleneck characteristic.Firstly,in this paper,the way of composite definition is used to calculate comprehen-sive bottleneck degree of the devices form the perspectives of relative production load,utilization rate and length of the buffer queue to indicate bottleneck based on bottleneck identification mechanism;Secondly,establish the model of growing and pruning neural networks to predict the future bottleneck and adjust the network structure in view of closed-loop control. Thirdly,in order to analyze the key factors relative to bottleneck devices and the dynamic bottleneck characteristic quantita-tively,the single factor test method was applied in this paper.Lastly,the experiments show that this dynamic bottleneck anal-ysis method is testified the feasibility and availability.%瓶颈设备是制约半导体生产线在制品水平、生产周期及准时交货率的关键因素,对其进行有效地分析能够提高生产线多性能。现有的分析方法主要是将瓶颈设备视为静态瓶颈,未考虑到生产线不确定因素所带来的动态漂移问题,这样容易造成以瓶颈设备控制为核心的调度算法缺乏柔性,降低算法实效性,因此,本文提出一种基于增长修剪型神经网络的动

  6. 基于丢包区分及共享瓶颈的MPTCP拥塞控制算法%M PTCP congestion control algorithm based on packet loss differentiation and shared bottleneck link

    Institute of Scientific and Technical Information of China (English)

    黄宏程; 陆卫金; 刘建星; 胡敏

    2016-01-01

    To utilize resource efficiently in unshared bottleneck link and resolve the problem that the congestion window declines sharply for the lack of loss differentiation mechanism in existing multipath TCP (MPTCP) congestion control algorithm ,a MPTCP congestion control algorithm based on packet loss differentiation and shared bottleneck link was presented .The size of congestion window was adjusted dynamically by detecting whether subflows shared the common bottleneck link ,and network resource was then fully utilized .Wasting network resource was avoided by introducing loss differentiation mechanism in hetero‐geneous network .Results of the simulation indicate the algorithm can improve the throughput of MPTCP connection .%为有效利用非共享瓶颈链路处的网络资源并解决多路径传输控制协议(multipath TCP , M PTCP)应用在异构网络中缺少丢包区分机制导致拥塞窗口急剧下滑等问题,提出一种基于子流丢包区分及共享瓶颈的M PTCP拥塞控制算法。通过检测M PTCP中子流共享瓶颈的情况,进行动态地调整拥塞窗口,充分利用非共享瓶颈链路处的网络资源;在M PTCP应用于异构网络时,引入丢包区分机制,避免因非拥塞丢包浪费网络资源。实验结果表明,与现有 M PTCP拥塞控制算法相比,该算法确保了共享瓶颈公平性,改善了网络的吞吐量性能。

  7. Bottleneck Identification for the Gathering and Distributing Capacity of Urban Rail Transit Station%城市轨道交通车站集散能力瓶颈识别方法研究

    Institute of Scientific and Technical Information of China (English)

    单征; 宋瑞; 李婷婷; 陈立扬

    2014-01-01

    The bottleneck for the gathering and distributing capacity of urban rail transit station leads to serious passenger traffic congestion and reduces the distribution performance of stations ,which affects the efficiency and safety of passenger travel .Based on the full analysis of the connotation and cause of the gathering and distributing capacity bottle-neck of urban rail transit station ,the bottleneck identification method based on the congestion level is put forward .First-ly ,the cumulative Logistic regression based on a congestion level measurement model is built .Then ,the model is calibra-ted and validated with the survey data .Finally ,by taking Beijing Dongzhimen Rail Transit Station as the study site ,the validity of the model is verified by using Anylogic dynamic simulation .Results show that the model can accurately reflect the bottleneck of the gathering and distributing capacity of urban rail transit station in real time .%城市轨道交通车站集散能力瓶颈会导致车站内部分区域出现严重的客流拥堵现象,降低车站集散效能,影响乘客出行效率和安全。在分析城市轨道交通车站集散能力瓶颈内涵和成因的基础上,提出了基于拥堵强度的瓶颈识别方法。构建基于累计 Logistic 回归的拥堵强度判别模型,结合调查数据对模型进行参数标定和验证。以北京地铁东直门站为例,结合 Anylogic 动态仿真,验证了模型的有效性,表明该模型能够准确、实时地识别出城市轨道交通车站集散能力瓶颈。

  8. Production Technology Status and Bottleneck Problem Analysis of Industrial Detonator in China%我国工业雷管生产技术现状与瓶颈问题分析∗

    Institute of Scientific and Technical Information of China (English)

    廖玉景

    2016-01-01

    Industrial detonator production development technology in China has been significantly improved in this years, es-pecially the“twelfth five-year” period, a large number of independent research and development which has the function of in-trinsically safe automation equipment get pilot application. In the paper, by comparing the status of industrial detonator pro-duction technology at home and abroad, the bottleneck problem of industrial detonator production automation degree is found out, and then,the method solving the bottleneck problem is put forward, which can provide reliable technical solution for reali-zing full automation industrial detonator production subsequently.%我国工业雷管生产经过多年的发展技术水平已有明显提高,特别是“十二五”期间,大批自主研发的具有本质安全功能的自动化设备得到试点应用。通过对比国内外工业雷管生产技术现状,找出制约工业雷管生产自动化程度的瓶颈问题,通过分析比较,提出解决瓶颈问题的方法,为后续实现工业雷管生产全程自动化提供可靠的技术方案。

  9. 广场舞对老年人生活质量的影响与发展瓶颈%A research on the square dance’influence to the old people’s life quality and its bottleneck of development

    Institute of Scientific and Technical Information of China (English)

    邹荣霞; 陈军

    2015-01-01

    对广场舞特点和其产生的影响与发展瓶颈进行分析,建议政府应关心、重视老年人体育文化生活,尽力解决制约广场舞发展的瓶颈;学校和媒体应积极参与,加强社会各界关注,使广场舞健康而快速发展。%The characteristics and the influence of square dance as well as its development bottleneck were described to suggest that the government should take care of and attach importance to sports and cultural life of the elderly,trying to solve the bottleneck restricting the development of square dance. Schools and media should be actively involved in to strengthen the social attention from all walks of life to make the square dance get healthy and rapid development.

  10. 辽宁省沟域旅游发展的瓶颈问题及解决对策%The Bottlenecks of Valley Tourism of Liaoning Province and the Countermeasures

    Institute of Scientific and Technical Information of China (English)

    吕同猛

    2013-01-01

    通过对沟域、沟域经济的概念介绍,引出沟域旅游的概念。通过介绍近年来辽宁省沟域旅游发展的概况,归纳整理出辽宁省发展沟域旅游过程中遇到的瓶颈,并根据这些瓶颈问题有针对性地提出解决对策。笔者从资金投入、融资渠道、土地利用、科学规划、人才培养、标准化服务等方面,提出了切实可行的措施和方法。%The article introduces the concept of Valley and Valley Economy into the concept of Valley Tourism. By introducing the development situation of the Valley Tourism of Liaoning Province in recent year, it sums up the bottlenecks of Valley Tourism in the process of tourism development, and then puts forward countermeasures to these bottlenecks. The author puts forward practical measures and methods from the investment, financing, land use, scientific planning, personnel training, standardized services, etc.

  11. Low genetic diversity and local adaptive divergence of Dracaena cambodiana (Liliaceae) populations associated with historical population bottlenecks and natural selection: an endangered long-lived tree endemic to Hainan Island, China.

    Science.gov (United States)

    Zheng, D-J; Xie, L-S; Zhu, J-H; Zhang, Z-L

    2012-09-01

    Historical population bottlenecks and natural selection have important effects on the current genetic diversity and structure of long-lived trees. Dracaena cambodiana is an endangered, long-lived tree endemic to Hainan Island, China. Our field investigations showed that only 10 populations remain on Hainan Island and that almost all have been seriously isolated and grow in distinct habitats. A considerable amount of genetic variation at the species level, but little variation at the population level, and a high level of genetic differentiation among the populations with limited gene flow in D. cambodiana were detected using inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analyses. No significant correlation was found between genetic diversity and actual population size, as the genetic diversities were similar regardless of population size. The Mantel test revealed that there was no correlation between genetic and geographic distances among the 10 populations. The UPGMA, PCoA and Bayesian analyses showed that local adaptive divergence has occurred among the D. cambodiana populations, which was further supported by habitat-private fragments. We suggest that the current genetic diversity and population differentiation of D. cambodiana resulted from historical population bottlenecks and natural selection followed by historical isolation. However, the lack of natural regeneration of D. cambodiana indicates that former local adaptations with low genetic diversity may have been genetically weak and are unable to adapt to the current ecological environments.

  12. Economically Underdeveloped Areas of Housing Provident Fund Performance Bottlenecks and Countermeasures%经济欠发达地区住房公积金绩效瓶颈及对策--以江苏省宝应县为例

    Institute of Scientific and Technical Information of China (English)

    李飞

    2015-01-01

    近年来,由于公平和效率的缺失使得住房公积金制度的合理性备受诟病。虽然这些指责缺乏一定的科学依据,但也从侧面说明了制度的优势和效能正在减弱,住房公积金发展的确遇到了瓶颈问题。特别是一些经济欠发达地区住房公积金中心受制于区域经济欠发达等因素,其运行绩效难以快速提升。通过分析宝应县这样一个典型的经济欠发达县市住房公积金运行特点,剖析和总结制约其绩效提升的一些瓶颈因素,并就如何突破发展瓶颈,提出了一些可供参考的建议和应对策略。%In recent years,due to the lack of fairness and efficiency of the housing accumulation fund system rationality criticized.Although these blamed the lack of scientific basis,but also from the side that the institutional advantages and effectiveness is weakening, housing provident fund development has encountered a bottleneck problem.Especially in some economically underdeveloped areas of housing provident fund center is subject to regional economic underdeveloped and other factors, its performance is difficult to quickly upgrade.In this paper,through the analysis of BaoYing county is a typical kind of underdeveloped counties housing provident fund operation characteristics, analyzing and summarizing the performance improvement of some bottleneck factors, and on how to break the bottleneck of the development,put forward some suggestions for reference and coping strategies.

  13. 科研院所科技成果产业化瓶颈及对策研究%Research on the Bottleneck and Countermeasures of Industrialization of Scientific and Technological Achievements in Institute of Science

    Institute of Scientific and Technical Information of China (English)

    马敬春

    2015-01-01

    本文从5个方面剖析了科研院所科技成果产业化存在的瓶颈,并有针对性地提出对策,对推动科技成果产业化有一定的指导作用。最后,通过A科研院所科技成果产业化的案例,分析对策的应用价值。%This article analyzes the bottleneck of scientific and technological achievements industrialization of scientific research institutes from five aspects, and proposes targeted measures which have some guidance to promote the industrialization of scientific and technological achievements. Finally, the industrialization of scientific and technological achievements of A Scientific Research Institute is used as tha case to evaluate the countermeasures.

  14. Application of the quasi-sliding-mode control to traffic bottleneck in pedestrian channel%准滑模控制应用于行人通道的交通瓶颈

    Institute of Scientific and Technical Information of China (English)

    曾广湘; 薛郁

    2011-01-01

    The congestion of pedestrian traffic occurs easily at the bottleneck. Barriers could impede pedestrian channel, but it can ensure the smooth flow of pedestrians. Quasi-sliding mode control will be introduced in LWR model. The control variable can be derived for simulation at the impact of barriers. Based on the three-lane macroscopic traffic flow model, we carry out simulation to verify our control methods. The results indicate that the maximum pedestrian flow can be maintained due to the threshold value of the quasi-sliding mode control variables as the threshold value corresponds to one of the maximum flows in the fundamental diagram. Optimization of control variables can improve efficiency of one-way pedestrian at bottleneck.%单向行人交通在瓶颈处极易发生堵塞,设置障碍会阻碍行人通行,却能保证瓶颈处通畅.本文将准滑模控制引入LWR模型中,理论推导控制变量.在三车道宏观交通流模型基础上,模拟瓶颈处的障碍对行人流的影响,解释设置障碍的作用.研究表明准滑模控制变量的设置与阈值有关,当阈值对应基本图的流量最大点时,行人流量能保持最大值,达到提高单向行人交通瓶颈处的行人流通过效率.

  15. Uniform Travel Credit Scheme for Managing Bottleneck Congestion and Modal Split%均匀行驶信用券计划管理瓶颈拥挤和方式划分

    Institute of Scientific and Technical Information of China (English)

    田丽君; 陈捷娜; 许岩; 李红

    2012-01-01

    在相互竞争的双模式交通系统中,考虑用户异质性,本文探讨了均匀行驶信用券计划对方式划分和帕累托提高特性的影响.在这一计划下,政府首先发布一定数量的行驶信用券,并均匀地分发给每一位出行者,允许出行者根据自身需求在市场中自由购买或出售信用券.根据预先设定的行驶信用券收取规模,使用快速路的出行者将会在经过瓶颈时被收取一定数量的信用券.研究结果表明,均匀行驶信用券计划总能让一部分快速路出行者转向地铁模式;对于同质用户来说,无论信用券收取数量多少,帕累托提高特性始终成立,然而对于异质用户来说,只有当行驶信用券收取数量小于某一临界值时,帕累托提高特性才能满足.%In a competitive two-mode network, this paper aims at exploring the effect of the uniform travel credit scheme on modal split and Pareto-improving property considering the heterogeneous VOT of users. Under the uniform travel credit scheme, the government initially issues a total amount of credits and distributes them to each eligible user in a uniform manner, which are allowed to trade in a competitive market. Therefore, travelers can buy or sell their credits according to their own travel need. An amount of uniform credits are charged for usage of highway bottleneck according to the pre-defined credit charging scales. The results show that the uniform travel credit scheme always makes some auto users transfer to transit mode to some extent, and the Pareto-improving property is always true for the homogeneous case whatever the credit charging scale is. However, for the heterogeneous case, the study shows that Pareto-improving property only satisfies when the credits charged at bottleneck are less than a critical value.

  16. 关中地区休闲旅游产业发展的瓶颈与破解∗%On the Development Bottlenecks of Leisure Tourism Industry and Crack Methods in GuanZhong Area of Shanxi Province

    Institute of Scientific and Technical Information of China (English)

    张金凤

    2016-01-01

    s:The leisure and tourism industry in Guanzhong region have related to the development of tourism industry in Guanzhong-Tianshui Economic Zone and Silk Road Economic Belt.However,the devel-opment of tourism industry has been restricted by the main bottleneck in the area.Such as uneven tourism re-sources distribution;poor economic benefit and tourist traffic;insufficient tourism experience;lacking mar-keting and the unknown cultural characteristics.In order to optimize the development of leisure tourism in-dustry in Guanzhong area,it must be broke the bottlenecks from the following five aspects:planning scientif-ically to form large tourism circle;optimizing transportation and construct direct line of tourist;updating ideas to build a well-known tourist brand;breaking the old board to explore global travel patterns;digging the connotation deeply to increase tourism attractions.%关中地区休闲旅游产业的发展关联着关天经济区与丝绸之路经济带的发展。然而旅游资源分布不均、经济效益不佳、旅游体验不足、市场营销不够、旅游交通不畅和文化特色不显是制约关中地区休闲旅游产业发展的主要瓶颈。以科学规划,形成大旅游圈;优化交通,建设旅游直达专线;更新观念,打造知名旅游品牌;打破旧局,探索全域旅游模式;深挖内涵,增加旅游吸引力来破解关中地区休闲旅游产业发展的瓶颈,加快关中地区休闲旅游产业发展。

  17. 我国冷链物流发展瓶颈分析与破颈探讨%Analysis on the Development Bottleneck of Cold-Chain Logistics and Its Solutions

    Institute of Scientific and Technical Information of China (English)

    何晓林; 孙莉; 张晓静

    2014-01-01

    As a special form of logistics, cold-chain logistics is becoming increasingly important and attracts unprecedented attention. On the basis of elucidation of the definition, characteristics and standards of cold-chain logistics, this essay places priority on the bottleneck that has restricted the development of cold-chain logistic in China and explores the possible solutions to tackle these problems.%冷链物流作为一种特殊的物流形式日益发挥着重要的作用,也引起了前所未有的关注。本文在全面阐述冷链物流含义与特征以及遵循原则的基础上,重点分析了制约我国冷链物流发展的瓶颈,系统探讨了解决我国冷链物流发展瓶颈的对策。

  18. The Analysis and Countermeasures for Breaking the Bottleneck of Small and Medium-sized Enterprises’ Funds%破解中小企业资金瓶颈的分析及对策

    Institute of Scientific and Technical Information of China (English)

    杜轶龙

    2011-01-01

    This paper introduces the dilemma of the medium and small enterprises in China in the existing financing mode, and thinks that from China's economic transformation and upgrading of the long-term development, the realistic meaning and urgency of breaking small and medium-sized enterprise capital bottleneck must be considered, and expounds that the financial institutions play the role of investment intermediary and actively promote the innovation of financial market instruments.%文章介绍了我国中小企业在现有融资方式下面临的困境,并从中国经济长远发展和升级转型的角度思考破解中小企业资金瓶颈的现实意义和紧迫性,阐述了发挥金融机构投资中介的作用,积极推进金融市场工具的创新试点的建议措施.

  19. 以瓶颈资源为基础的生产与库存控制系统的构建%Construction of production and inventory control system based on bottleneck resources

    Institute of Scientific and Technical Information of China (English)

    徐学军

    2001-01-01

    当前较为成熟的生产与库存控制系统中, MRP( II)强调生产能力的平衡与利用,而忽视了物流效率; JIT重视物流效率,而以生产能力的闲置为代价。本文依据约束管理的理论,构建以瓶颈资源为基础的生产与库存控制系统,使得在有效利用生产资源的同时,提高物流的效率。%As one of prevailing production and inventory control systems, MRP( II) attaches importance to utilizing and balancing of production capability, but ignoring efficiency of material flow. Also, JIT pinpoints efficiency of material flow,but leading to lower utilizing of production capability. In order to both raise efficiency of material flow and improve utilizing of production capability, this paper probes into construction of production and inventory control system on bottleneck resources according to theory of constrains management.

  20. 同步感应线圈炮的技术瓶颈与应用前景分析研究%Technology Bottleneck and Application Prospect of Synchronous Induction Coil Gun

    Institute of Scientific and Technical Information of China (English)

    向红军; 李治源; 雷彬

    2012-01-01

    The paper introduces the working principle of multistage synchronous inductive coil gun, and analyzes the technology bottleneck of coil gun such as the storage energy miniaturization, position triggering and the lifetime of driving coils. Then it draws the conclusion that the synchronous inductive coil gun is suitable for the low and medium armature velocity launching. Finally, it studies the application prospect of synchronous inductive coil gun in electromagnetic mortar, high mass load ejecting and fuse dynamic experiment, which is useful for the development of the synchronous inductive coil gun in the future.%介绍多级同步感应线圈炮的工作原理,分析目前同步感应线圈炮在储能电源小型化、位置触发及驱动线圈寿命等方面的技术瓶颈,得出同步感应线圈炮更适用于中低初速载荷发射的结论,同时,研究同步感应线圈炮在电磁线圈迫击炮、大质量载荷弹射和引信动态试验等方面的应用前景,为科学制定同步感应线圈炮发展战略奠定了基础.

  1. Bottleneck problems and countermeasures of nursing team construction in the secondary hospitals%影响二级医院护理队伍建设的瓶颈问题及对策

    Institute of Scientific and Technical Information of China (English)

    钟郁鸿

    2015-01-01

    本文分析了影响二级医院护理队伍建设的瓶颈问题,重点提出了以更新观念,稳定护理队伍;优化知识结构,提高护士专业素质;健全科研创新管理机制,提高科研能力;建立竞争机制,营造人才成长的良好氛围;适应护理专业发展,打造临床护理专家队伍的对策措施。%This paper analyzes the bottleneck problems of nursing team construction in level two hospitals and proposes the countermeasures to solve the problems, including updating concepts, stabling nursing team;optimizing the knowledge structure, improving nursing professional quality;improving scientific research and innovation management mechanism, enhancing research capacity;establishing competitive mechanism, creating a good atmosphere for the talent growth;adapting nursing professional development, and building clinical nursing service team.

  2. 书外功夫:中国书法之外域传播瓶颈%Efforts Outside Calligraphy:Bottleneck of Chinese Calligraphy’s International Communication

    Institute of Scientific and Technical Information of China (English)

    杨加深

    2013-01-01

    As an art based on Chinese characters, it seems that Calligraphy could arouse the resonance of foreign cultures simply by its external forms without taking the language barrier in consideration. But in fact, as the very soil of calligraphy, the Chinese culture not only produced and developed calligraphy, but also becomes the bottleneck during the process of international exchange and communication. Thus, the efforts out of calligraphy -the various Chinese cultures related to calligraphy, not only become the key to improving the level of Chinese calligraphers, but also become the chokepoints of real comprehension by the foreigners. If we really want to improve its international communication, the efforts made on the relative Chinese cultures become an inevitable gateway.%书法是在汉字基础上发展起来的一门艺术。尽管从表面上看,书法似乎可以仅仅凭借外在的形式跨越语言障碍而唤起异国文化的共鸣,但实际上,其赖以产生和发展的中国文化土壤本身,同时也成为影响其对外传播与交流的瓶颈。书外功夫,实际上就是与书法相关的中国文化因素之总和,它不但是国人提升书法境界的关键,也是中国书法被异域文化所真正理解的“铁门限”。欲实现深层次的书法外域传播,书外功夫是一道必经的关口。

  3. 翻转课堂在我国发展的瓶颈及路向选择%The Bottlenecks and Path Alternatives to Flipped Classroom Development in Our Country

    Institute of Scientific and Technical Information of China (English)

    韩丽珍

    2013-01-01

      翻转课堂作为新兴的教育理念及教学模式,为教师提供个性化教学平台,为学生提供个性化学习空间。学生通过课外的自主学习,课内的协作互动,掌握及内化知识。翻转课堂在我国的发展受固有的传统教育文化、教学条件的制约,有必要对其进行本土化改进,寻找适合我国翻转课堂教学的发展路向。通过对翻转课堂的理念及优势进行论述,深入剖析其在我国发展瓶颈,提出翻转课堂在我国的发展路向。%As the emerging philosophy of education and teaching mode , flipped classroom provides personalized teaching platform for teachers and personalized learning space for students .Students acquire and internalize knowledge through extracurricular au-tonomous learning and collaboration in the classroom .The development of the flipped classroom was restricted by the educational culture of inherent tradition and teaching conditions in our country .So it is necessary to make localization improvements and look for suitable direction of development for the flipped classroom teaching in China .After discussing the idea and advantages of the flipped classroom, and analyzing the bottleneck of its development in China , this paper puts forward direction of development of the flipped classroom in our country .

  4. 城市轨道交通车站客流瓶颈应对措施研究%The Measures For Passenger Flow Bottleneck in Rail Transit Station

    Institute of Scientific and Technical Information of China (English)

    俞亦舟

    2016-01-01

    随着城市轨道交通的发展,线网规模不断扩大,客流量急剧增加的同时也考验车站设备设施的运输通过能力。为了避免车站出现严重拥堵现象,保障乘客出行效率和安全,本文以即将开通的广州地铁6号线二期金峰站为例,通过模拟乘客走行路径,分析车站各关键节点通过能力,得出车站的客流瓶颈,并提出在设备能力有限的情况下车站的应对措施。%With the development of the urban rail transit, the scale of the line is increasing, the passenger flow has increased rapidly, but also test the transport capacity of the station equipment and facilities. In order to avoid serious congestion in the station, guarantee the efficiency and safety of passengers’travel, in the forthcoming opening of the Guangzhou Metro Line 6, the second phase of Jin Feng Station as an example, through simulating the passengers walk’s path and analysis the key points of transport capacity, finally draw the station’s passenger flow bottleneck, and put forward the corresponding measures.

  5. Integration Process Combined Records and Archives: the Bottleneck of Government OA%文档一体化流程:政府办公自动化的瓶颈

    Institute of Scientific and Technical Information of China (English)

    赵屹; 陈晓晖

    2011-01-01

    The document process has been the prime problem and the bottleneck in the document management of OA systems. Specifically speaking, current problems existed in the document process are dispersive function, relatively closed situation and respective management. And also because the OA systems based on the process neglects the long-term preservation requirement for the archives management, the electronic documents preserved in these OA systems can't act as evidence. In order to solve the problem, we must design a national official document process to implement the whole-process management combined records and archives, unify the management system of records and archives and update the development model of OA.%当前政府办公自动化系统的公文管理功能普遍存在问题,其中的瓶颈亦即最根本性的问题是公文流程问题。当前政府公文流程存在功能分散、相对封闭、文档分治等主要问题。基于这种流程开发的办公自动化系统忽略了档案管理中对于电子公文长期保存的需求,所保存下来的电子公文将来无法作为档案发挥应有的凭证作用。要解决这个问题,必须研究并设计国家层面的电子公文流程,实现文档一体化的全程管理,统一文档管理体制,更新办公自动化系统开发模式。

  6. Characterizing correlations of flow oscillations at bottlenecks

    Science.gov (United States)

    Kretz, Tobias; Wölki, Marko; Schreckenberg, Michael

    2006-02-01

    'Oscillations' occur in quite different kinds of many-particle systems when two groups of particles with different directions of motion meet or intersect at a certain spot. In this work a model of pedestrian motion is presented that is able to reproduce oscillations with different characteristics. The Wald-Wolfowitz test and Gillis' correlated random walk are shown to include observables that can be used to characterize different kinds of oscillations.

  7. Characterizing correlations of flow oscillations at bottlenecks

    OpenAIRE

    Kretz, Tobias; Woelki, Marko; Schreckenberg, Michael

    2006-01-01

    "Oscillations" occur in quite different kinds of many-particle-systems when two groups of particles with different directions of motion meet or intersect at a certain spot. We present a model of pedestrian motion that is able to reproduce oscillations with different characteristics. The Wald-Wolfowitz test and Gillis' correlated random walk are shown to hold observables that can be used to characterize different kinds of oscillations.

  8. Structural bottlenecks for communication in networks.

    Science.gov (United States)

    Sreenivasan, Sameet; Cohen, Reuven; López, Eduardo; Toroczkai, Zoltán; Stanley, H Eugene

    2007-03-01

    We consider the effect of network topology on the optimality of packet routing which is quantified by gammac, the rate of packet insertion beyond which congestion and queue growth occurs. We show that for any network, there exists an absolute upper bound, expressed in terms of vertex separators, for the scaling of gammac with network size N, irrespective of the static routing protocol used. We then derive an estimate to this upper bound for scale-free networks and introduce a static routing protocol, the "hub avoidance protocol," which, for large packet insertion rates, is superior to the shortest path routing protocol.

  9. EU to tackle trucker bottlenecks / Todd Graham

    Index Scriptorium Estoniae

    Graham, Todd

    2006-01-01

    Läti peaminister Aigars Kalvitis ütles Euroopa Komisjonis, et veoautode järjekorra probleem piiril on ka Euroopa ühine mure. Ainult Venemaa tolli olukorras süüdistada ei saa. Tabel: Trucks on the border

  10. Bottlenecks of blood processing in Uganda

    NARCIS (Netherlands)

    Kajja, I.; Kyeyune, D.; Bimenya, G. S.; Sibinga, C. T. S.

    2010-01-01

    Aim: To identify where and why delays occur in Uganda blood banks. Background: The timely provision and supply of safe and efficacious blood components to hospitals depends on sound systems in the processing blood banks. Poorly managed systems lead to apparent blood shortages in hospitals and increa

  11. Step tolling with bottleneck queuing congestion

    NARCIS (Netherlands)

    Berg, van den V.A.C.; Verhoef, E.T.; Lindsey, C.R.

    2012-01-01

    . It also proposes a third scheme in which late in the rush hour drivers slow down or stop just before reaching a tolling point, and wait until the toll is lowered from one step to the next step. Such ‘braking’ behaviour has been observed in practice. Analytical derivations and numerical modelling s

  12. 集体公益林承包户经济权利保障的瓶颈与突破%Bottleneck and Breakthrough for Economic Right Guarantee of Contracted Households of Collective Forest

    Institute of Scientific and Technical Information of China (English)

    吴楠

    2014-01-01

    China’ s collective forest right reform aims to realize ecological civilization and to increase the income of forest farmers, therefore, the commodity forest and public-benefiting forest with collective ownership are brought into forest right system reform, however, public-benefiting forest takes more ecological function so that the contracted rights of the households for public-benefiting forest are limited accordingly. Currently, the bottleneck for contracted households of collective public-benefiting forest to realize their economic rights is the contradiction between market-oriented forms and planning-economic system, the contradiction between economic development and environment protection and the contradiction between policy demand and policy shortage, as a result, China should face the national situation, clarify legal borders, emphasize benefit coordination, and realize collaborative development between economy and ecology as well as society by implementing main body reform, by deepening matched reform, by perfecting forest ecological benefit compensation system and by legally protecting the economic rights of contracted households of the public-benefiting forest.%我国集体林权制度改革是为了实现生态文明,也是为了增加林农收入;集体所有的商品林、公益林都被纳入了林权制度改革,然而公益林承担了更多的生态功能,公益林承包户的承包经营权相应也受到了更多的限制。目前,市场化形式与计划型体制的矛盾、经济发展与环境保护的矛盾、政策需求与政策缺位之间的矛盾是限制集体公益林承包户实现其经济权利的瓶颈,应正视国情、厘清法定边界、重视利益协调,通过落实主体改革、深化配套改革、完善森林生态效益补偿制度,依法保障公益林承包户的经济权利,实现经济、生态和社会的共同发展。

  13. Analysis on Real-Time Bottleneck Factors Influencing Power System Recording System%电力录波系统实时性瓶颈影响因素分析

    Institute of Scientific and Technical Information of China (English)

    邢浩江; 张东来; 张斌; 王超; 李悦

    2011-01-01

    电力录波系统的性能受多因素制约,以致系统实时性较难提高,鉴于此,采用改进的基于链路层网络传输方法,通过应用层直接访问网络控制器,避免了系统中对数据帧的封装与解析的冗余操作,提高了系统实时性.通过对系统中各接口数据处理时间的精确测量,可知制约电力录波系统实时性的主要因素为处理器间总线访问速度、录波文件形成效率、故障文件存储与网络传输速度,且网络传输速度为影响系统实时性瓶颈因素.通过后置存储功能,调整并行总线访问模式,优化故障录波文件形成逻辑,以减小对实时性的影响.实际测试验证了系统功能的有效性与实时性.%The performance of power recording system is restricted by many factors so that it is difficult to improve the real-time performance of recording system. For this reason, to improve real-time performance of power recording system such measures as utilizing improved link-layer based network transmission technique and directly accessing network controller via application layer to avoid the redundant operation in data packaging and unpacking are proposed. By means of accurately measuring processing time of interface data within the recording system the main restrictive factors, including bus accessing speed among processors, forming efficiency of record files, storage of fault files and network transmission speed, are revealed, and the network transmission speed is the very bottleneck factor influencing the real-time performance of the recording system.Using the measures such as postposition of storage function,adjusting parallel bus access mode and optimizing forming logic of recorded fault file, the influence of these factors on real-time performance of the recording system is mitigated. Actual testing results verify the effectiveness and real-time performance of the improved recording systen.

  14. 公交车停靠诱发交通瓶颈的元胞自动机模拟%Investigation on traffic bottleneck induce by bus stopping with a two-lane cellular automaton model

    Institute of Scientific and Technical Information of China (English)

    李庆定; 董力耘; 戴世强

    2009-01-01

    利用双车道元胞自动机模型,研究公交车停靠对道路混合交通流的影响.针对港湾式和非港湾式两种不同公交车站设置,在开放边界下模拟了公交车停靠所产生的交通瓶颈问题,给出了车辆入流概率.公交车比例相平面上的相图,区分了自由流相和拥挤相,研究了相图各区中公交车站附近的平均密度和速度分布图,比较了两种公交车站情况下的道路交通流的动力学特征.研究发现,当公交车比例较小时,与非港湾式车站相比,港湾式车站可以显著改善车站处的交通状况.%In this paper, the influence of typical bus stops on traffic flow is investigated with the cellular automaton traffic model. For on-line and off-line bus stops, a two-lane cellular automaton model is proposed to simulate the traffic bottleneck induced by bus stopping under the open boundary condition. The phase diagram in the phase plane of injection probability and bus fraction is provided and two phases, i.e., the free flow phase and congested flow phase, are distinguished. The distributions of the mean density and velocity near the bus stop in different traffic phases are given and the comparison of dynamical characteristics of traffic flows is made for different types of bus stops. It is found that using the off-line bus stop can significandy improve the traffic flow in its neighboring region, compared with the on-line bus stop in the case of small fraction of buses.

  15. Research on T raffic Flow Rate Features at U rban Expressw ay Bottleneck Near Off-ramp%城市快速路出口匝道瓶颈区域交通流率特征研究

    Institute of Scientific and Technical Information of China (English)

    李晓庆; 王忠宇; 吴兵

    2015-01-01

    分析城市快速路出口匝道附近的交通流率特征,对确定通行能力和提出管理措施具有重要意义。针对城市快速路线圈检测数据,利用方差分析和配对样本检验分析比较出口匝道瓶颈区域各车道之间交通拥挤前后的流率变化。发现内侧车道的交通流率在拥挤之前低于外侧车道,而在拥挤期间高于外侧车道。外侧车道在拥挤之后的排队消散流率会显著降低,而内侧车道的消散流率反而增加,即存在早发性交通拥挤的现象,并通过流量‐速度关系图对内外车道交通流特征的差异进行阐释。%It’s significant to analyze the characteristics of traffic flow rate at urban expressway bottle‐neck near off‐ramp w hen determining road capacity and proposing traffic management measures .Based on loop detector data ,one‐way ANOVA (Analysis of Variance) and paired samples test are used to analyze the changes of traffic flow rate in each lane of an urban expressway bottleneck near off‐ramp when the traffic congestion occurs .It shows that the pre‐queue flow of inside lanes are lower than outside lanes’ before traffic congestion ,but higher than outside lanes’ during traffic congestion peri‐od .And the queue discharge flow of outside lanes will significantly reduce after congestion ,but inside lanes’ will significantly improve which means that the inside lanes experience an early‐onset of traffic congestion .Furthermore ,the flow‐velocity diagrams are used to explain the differences of traffic flow features between inside and outside lanes .

  16. Optimization of Energy Storage System Capacity for Relaxing Peak Load Regulation Bottlenecks%用于松弛调峰瓶颈的储能系统容量配置方法

    Institute of Scientific and Technical Information of China (English)

    严干贵; 冯晓东; 李军徽; 穆钢; 谢国强; 董效辰; 王芝茗; 杨凯

    2012-01-01

    利用大规模电池储能系统对电网负荷“削峰填谷”,减少日负荷波动幅度,可以缓解发电机组对负荷追踪调控负担,使电网具备更多向下调节容量来接纳风电.基于给定的负荷特性,分析储能系统配置容量与其改善负荷波动水平之间的关系,以储能系统投资成本、经济效益为约束,以综合效益最大为目标,提出一种用于松弛调峰瓶颈的大规模储能系统容量优化配置方法.针对2010年某省电网接纳风电受限现状,利用该方法对其进行改善,分析了储能系统运行年限、投资成本对其容量配置的影响,算例结果验证了所提出方法的可行性.%Using large-scale battery energy storage systems for load shifting and peak smoothing can decrease the fluctuation of daily load and reduce load tracking regulation burden of generator units, and enlarge down-regulate space to accommodate wind power. Based on a given load characteristics, the relationship between the energy storage system allocation capacity and improvement of load fluctuations was analyzed. By making energy storage system's investment costs and economic benefits as constraints, and by maximizing the comprehensive benefits as the object, an optimal capacity-allocation method was proposed for large-scale energy storage systems to relax peak-regulation bottleneck. For the limitation of wind power accommodation of a province in China in 2010, the method was applied to improve the situation and the impact of the life cycle and investment cost of the energy storage system on its capacity configuration. Case study results verified the feasibility of the proposed method.

  17. Bottleneck breakthrough of start-ups' growth : the mediating effect of government-enterprise interaction and the moderating effect of policy perception%创业企业成长瓶颈突破——政企互动的中介作用与政策感知的

    Institute of Scientific and Technical Information of China (English)

    彭华涛

    2013-01-01

    以政府部门推动创业企业成长的政策导向为自变量,以创业企业成长过程中的政企互动为中介变量,以创业企业的政策感知为调节变量,以创业企业成长的瓶颈突破为因变量,构建了相应的理论框架;借助于探索性因子分析、验证性因子分析、中介效应和调节效应的回归模型,得出:政策导向对于创业企业成长的瓶颈突破具有正向影响;政策导向通过政企活动部分中介作用于创业企业成长的瓶颈突破;政策感知对于政企互动与创业企业成长的瓶颈突破之间的关系具有显著的调节作用.%Taking the policy orientation of government to promote start-ups' growth as the independent variable,the government-enterprise interaction during start-ups' growth as the mediator variable,the policy perception of start-ups as the moderator variable,the bottleneck breakthrough of start-ups' existence and development,this paper built up corresponding theoretical framework.By means of EFA,CFA,the regression models of mediating effect and moderating effect,this paper got the conclusions that policy orientation wos positively relevant with the bottleneck breakthrough during start-ups' growth.Policy orientation positively influence the bottleneck breakthrough during start-ups' growth by means of the mediating effect of government-enterprise interaction.Policy perception has significantly moderating effect on the relationship between government-enterprise interaction and bottleneck breakthrough during start-ups' growth.

  18. Discussion on Non-Medical Bottleneck Factors Affecting City Grade Hospital to Carry Out Peritoneal Dialysis%市级医院开展腹膜透析的“非医疗瓶颈因素”探讨

    Institute of Scientific and Technical Information of China (English)

    万启军; 何永成; 许慧丽; 董旭; 宋海英

    2013-01-01

    Objective To discuss the non-medical bottleneck factors that affect the city grade hospitals to carry out the peritoneal dialysis(PD). Methods Retrospective analyze the clinical data of 160 cases of end-stage renal disease(ESRD) patients on continuous ambulatory peritoneal dialysis(CAPD) treatment from July, 1996 to December,2011 in our hospital,explore the influence of peritoneal dialysis center' s scale size,cost of dialysate,understanding of medical personnel and ESRD patients about peritoneal dialysis on the peritoneal dialysis in our hospital. Compare the difference of the main complications of CAPD between cumulative numbers of patients less than and more than 50; drop-out rate, time on treatment (TOT) ,1 year catheter intact rate and so on. Results The peritoneal dialysis was suggested only by 45. 6% of medical personnel in terms of cost-effect ratio,and by 51. 8% in terms of quality of life. Before the dialysate is charged as a drug,66. 8% of renal physicians suggested patients to choose hemodialysis,but it changed to 43.3% after dialysate is charged as a supply,there is a significant difference(P <0.05). When the cumulative numbers of patients was less than 50, the rates of drop-out rate,death rate, vessel drifting rate, rate of dialysate leaks,tunnel infection rate and PD associated peritonitis were all higher,but the TOT,1 year survival rate and 1 year vessel intact rate were lower,as compare with those when the cumulative numbers of patients was more than 50,and the difference was significance(P <0.05). Conclusion The misunderstanding of renal medicals and the ESRD patients, the way of medical payment and the size of the PD center together limited the speed of the development of PD center.%目的 探讨在市级医院开展腹透的“非医疗瓶颈因素”.方法 分析1996年7月-2011年12月间肾内科160例持续非卧床腹膜透析(CAPD)患者的临床资料,探讨腹透中心规模、腹透液计费方式、医患对腹透的认识等因

  19. 成人高等教育学生就业瓶颈探析——基于公共政策执行视角%Analysis of Employment Bottleneck for Students of Adult Higher Education ——Based on Perspective of Pub|ie Policy Implementation

    Institute of Scientific and Technical Information of China (English)

    韦仕祺

    2012-01-01

    Currently the employment for graduate students of aduh higher education is far from optimistic and the designing bottleneck in the system leads to one of the main difficulties in the employment, the reason of which is due to the deviation existing in the design of the system in the public policy and also the deviation can be caused by people who carry out the policy, leading to double psychological worries about learning at school and employment after graduation for adult students. The article tries to analyze the reason of employment bottleneck for students of adult education from the perspective of public policy and on this basis to explore some countermeasures and recommendations on fairness in employment supported by the policy.%当前成人高等教育毕业学生的就业状况不容乐观,究其原因是公共政策存在着制度设计上的偏差,同时人为地制造政策执行的偏差也引起了成人教育学生在校学习与毕业就业压力双重心理的担忧。本文从公共政策执行视角分析成人教育学生就业瓶颈的症结所在,并在此基础上提出成人教育学生获得政策公平就业对待的对策建议。

  20. 3D 打印技术与骨科植入物研发现状及其瓶颈突破思路%Research and Development Status and the Bottleneck Breakthrough Ideas of 3D Printing Technology and Orthopaedic Implants

    Institute of Scientific and Technical Information of China (English)

    汤啸天; 王燎

    2015-01-01

    植入物是骨肌系统治疗的核心要素,其社会及经济影响巨大。骨科植入物国产化及个体化需求倒逼研发工作;在骨科植入物研究领域中,3D 打印技术的临床应用已经铺平了道路,基于3D 打印技术的骨科植入物研发亟待法治化保障。个体化生产是3D 打印技术的优势也是法律限制的瓶颈,需改革创新方能突破3D 打印技术医疗应用瓶颈。破解3D 打印技术个体化生产医疗器械难题的思路:第一,报请国家食药监局批准在上海建立3D 打印技术临床应用试点;第二,建议签署《合作共识备忘录》共同防范风险;第三,建议开发特殊意外保险推进科学技术创新。%Implants are the core elements of skeletal muscle treatment system with enormous social and eco-nomic effects. The localized and individualized demand for orthopaedic implants forced its research and develop-ment work. In the research field of orthopedic implants, the way for clinical application of 3D printing technology has been paved, and the research and development of orthopaedic implants based on 3D printing technology need legal guarantee. Individualized production is the advantage of 3D printing and the bottleneck of legal restrictions as well, so reform and innovation are needed to break through its application bottleneck. And the following are the solutions to the problems in individualized production of medical equipments by 3D printing technology: 1. Submit to the National Food and Drug Administration for approval of setting up 3D printing pilot clinical application in Shanghai; 2. Suggest signing Consensus Memorandum of Cooperation to prevent common risks; 3. Suggest devel-oping special accident insurance to promote science and technology innovation.

  1. 智能电网——大规模风、光电并网瓶颈问题的解决方案%The smart grid─ the best of all scheme to solve the bottleneck problems of wind power and photoelectric power generation connected with power network on a large scale

    Institute of Scientific and Technical Information of China (English)

    徐娟; 孙大伟

    2012-01-01

    Aiming at the problems of the security and stability of power network caused by load undulation or power quality not good when wind power and photoelectric power generation connected with power network on a large scale.Through analyzing and comparing to find out: the smart grid with powerful capacity,facility and compatibility,con fit multiform power supply to connect with and contain it.The result of research shows that developing the smart grid maybe is the best of all scheme to solve the bottleneck problems of wind power and photoelectric power generation connected with power network on a large scale.%针对大规模风、光发电集中接入电网后产生的负荷波动性及电能质量较差,给电网带来的安全性和稳定性问题,通过分析对比发现,智能电网具有很好的智能性、灵活性和兼容性,不但成功地解决了上述问题还可以适应多种形式的电源接入并能将其成功消纳。研究表明:发展智能电网是解决大规模风、光发电并网瓶颈问题的最佳方案。

  2. The Bottleneck and Breakthrough of Ideals and Beliefs E-ducation of University Students:Based on the Empirical Study of Shanghai E University%大学生理想信念教育的瓶颈及其突破口--基于上海E大学的实证研究

    Institute of Scientific and Technical Information of China (English)

    陈兴珍; 曹亮

    2014-01-01

    In today's value diversification and social transforma-tion, university students' ideals and beliefs have presented new features mainly manifested in the coexistence of belief recognition and doubt at the ideological level, the coexistence of dedication spirit and interest choice at the life level, and the disconnection of subject simplicity and"instruction"at the educational level. How to well connect ideals and reality, educators and students, is the bottleneck as well as the breakthrough and focus of the ideals and beliefs education of university. In addition to the introduction of whole-student education at the subjective participation level, the education resources should also be integrated and the carrier construction of hierarchical education should also be perfected.%在价值多元化和处于社会转型期的当今,大学生理想信念呈现出新的特征,主要表现在思想层面上的信念认同和怀疑并存,生活层面上的奉献精神与趋利选择并存,以及教育层面上的主体单一性和“授受”脱节。如何做好理想与现实、教育者与学生间的接轨,是大学生理想信念教育面临的瓶颈,也是突破口和着力点。从主体参与层面引入全员育人的同时,也要整合教育资源,完善分层次教育的载体建设。

  3. The Bottleneck and Suggestion on the Improvement of the Competitiveness of Express Company in Beijing:Taking Yuantong Company as an Example%北京地区快递公司竞争力提升的瓶颈及建议 ——以圆通公司为例

    Institute of Scientific and Technical Information of China (English)

    沙明月; 刘璇

    2015-01-01

    随着电商平台对人们生活的影响日益明显,我国物流行业的发展也比较迅速,快递行业作为物流行业的重要组成部分,在北京地区的竞争呈现白热化,面对北京地区日益扩大的快递需求,快递公司的市场竞争力提升尤为重要,文章结合北京圆通快递公司的发展现状,分析其市场竞争力提升的瓶颈,并针对性地提出对策建议,旨在提高圆通快递公司的市场竞争力,在提供优质服务的基础上实现市场份额的扩张.%Due to the electric business influence on people's life has been increasingly obvious,the development of our logistics business is also very rapidly. As a main part of our logistics business ,the express industry in the competition of Beijing area has become heated. In the face of the growing demand of express in Beijing ,the grow of market competition of express company become more important. In this essay ,we analyze the promotion of the bottleneck of market competition and take out the suggestion targeted of the development of Beijing Yuan tong express company,in order to improve it's the market competition and achieve the expansion of market share in the base of providing high quality service.

  4. Bottlenecks to Clinical Translation of Direct Brain-Computer Interfaces

    Directory of Open Access Journals (Sweden)

    Mijail Demian Serruya

    2014-12-01

    Full Text Available Despite several decades of research into novel brain-implantable devices to treat a range of diseases, only two- cochlear implants for sensorineural hearing loss and deep brain stimulation for movement disorders- have yielded any appreciable clinical benefit. Obstacles to translation include technical factors (e.g., signal loss due to gliosis or micromotion, lack of awareness of current clinical options for patients that the new therapy must outperform, traversing between federal and corporate funding needed to support clinical trials, and insufficient management expertise. This commentary reviews these obstacles preventing the translation of promising new neurotechnologies into clinical application and suggests some principles that interdisciplinary teams in academia and industry could adopt to enhance their chances of success.

  5. De Knoflookpad in Nederland: ondergang of 'slechts' een bottleneck?

    NARCIS (Netherlands)

    Bosman, W.; Struijk, R.P.J.H.; Zekhuis, M.; Ottburg, F.G.W.A.; Crombaghs, B.; Schut, D.; Hoof, van P.

    2015-01-01

    In 2001 werd het landelijk Beschermingsplan Knoflookpad opgesteld. Wat is er sindsdien gedaan om de stand van de Knoflookpad te verbeteren en tot welke resultaten heeft dat geleid? Wat betekent dit voor de toekomst? Waar liggen de kansen voor de Knoflookpad? In een drietal artikelen komen achtereenv

  6. Search engines, the new bottleneck for content access

    NARCIS (Netherlands)

    van Eijk, N.; Preissl, B.; Haucap, J.; Curwen, P.

    2009-01-01

    The core function of a search engine is to make content and sources of information easily accessible (although the search results themselves may actually include parts of the underlying information). In an environment with unlimited amounts of information available on open platforms such as the inte

  7. A CAPACITY EXPANSION PROBLEM WITHBUDGET CONSTRAINT AND BOTTLENECK LIMITATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper considers a capacity expansion problem with budget constraint.Suppose each edge in the network has two attributes: capacity and the degree of difficulty.The difficulty degree of a tree T is the maximum degree of difficulty of all edges in the tree and the cost for coping with the difficulty in a tree is a nondecreasing function about the difficulty degree of the tree. The authors need to increase capacities of some edges so that there is a spanning tree whose capacity can be increased to the maximum extent.meanwhile the total cost for increasing capacity as well as overcoming the difficulty in the spanning tree does not exceed a given budget D*. Suppose the cost for increasing capacity on each edge is a linear function about the increment of capacity, they transform this problem into solving some hybrid parametric spanning tree problems[1] and propose a strongly polynomial algorithm.

  8. Power for All by 2012 - Bottlenecks and Strategies for Mission

    OpenAIRE

    Nisha Jain

    2012-01-01

    Power is a key factor that contributes to the industrialization and the economic growth of a country. It is one of the most important infrastructures on which the development of various economic sectors of a country depend. Availability of reliable and quality power at affordable rates is very crucial. It helps to make the domestic market competitive globally and thus enhance the quality of life for people. The nuclear, hydro, and thermal energy are the prominent sources of electricity genera...

  9. The Problem State: A Cognitive Bottleneck in Multitasking

    Science.gov (United States)

    Borst, Jelmer P.; Taatgen, Niels A.; van Rijn, Hedderik

    2010-01-01

    The main challenge for theories of multitasking is to predict when and how tasks interfere. Here, we focus on interference related to the problem state, a directly accessible intermediate representation of the current state of a task. On the basis of Salvucci and Taatgen's (2008) threaded cognition theory, we predict interference if 2 or more…

  10. The Problem State : A Cognitive Bottleneck in Multitasking

    NARCIS (Netherlands)

    Borst, Jelmer P.; Taatgen, Niels A.; van Rijn, Hedderik

    2010-01-01

    The main challenge for theories of multitasking is to predict when and how tasks interfere. He re, we focus on interference related to the problem state. a directly accessible intermediate representation of the current state of a task. On the basis of Salvucci and Taatgen's (2008) threaded cognition

  11. Host plant resistance to parasitic weeds; recent progress and bottlenecks.

    Science.gov (United States)

    Yoder, John I; Scholes, Julie D

    2010-08-01

    Parasitic witchweeds (Striga spp.) and broomrapes (Orobanche and Phelipanche spp.) directly invade the roots of crop plants connecting to the vascular system and abstracting nutrients and water. As a consequence they cause devastating losses in crop yield. Genetic resistance to parasitic weeds is a highly desirable component of any control strategy. Resistance to parasitic plants can occur at different stages of the parasite lifecycle: before attachment to the host, during penetration of the root or after establishment of vascular connections. New studies are beginning to shed light on the molecular mechanisms and signaling pathways involved in plant-plant resistance. The first resistance gene to Striga, encoding a CC-NBS-LRR Resistance protein (R) has been identified and cloned suggesting that host plants resist attack from parasitic plants using similar surveillance mechanisms as those used against fungal and bacterial pathogens. It is becoming clear that the salicylic acid (SA) signaling pathway plays an important role in resistance to parasitic plants and genes encoding pathogenesis-related (PR) proteins are upregulated in a number of the resistant interactions. New strategies for engineering resistance to parasitic plants are also being explored, including the expression of parasite-specific toxins in host roots and RNAi to silence parasite genes crucial for development.

  12. HIV/AIDS: global trends, global funds and delivery bottlenecks

    OpenAIRE

    Hadingham Jacqui; Coovadia Hoosen M

    2005-01-01

    Abstract Globalisation affects all facets of human life, including health and well being. The HIV/AIDS epidemic has highlighted the global nature of human health and welfare and globalisation has given rise to a trend toward finding common solutions to global health challenges. Numerous international funds have been set up in recent times to address global health challenges such as HIV. However, despite increasingly large amounts of funding for health initiatives being made available to poore...

  13. Fungal specificity bottlenecks during orchid germination and development.

    Science.gov (United States)

    Bidartondo, Martin I; Read, David J

    2008-08-01

    Fungus-subsidized growth through the seedling stage is the most critical feature of the life history for the thousands of mycorrhizal plant species that propagate by means of 'dust seeds.' We investigated the extent of specificity towards fungi shown by orchids in the genera Cephalanthera and Epipactis at three stages of their life cycle: (i) initiation of germination, (ii) during seedling development, and (iii) in the mature photosynthetic plant. It is known that in the mature phase, plants of these genera can be mycorrhizal with a number of fungi that are simultaneously ectomycorrhizal with the roots of neighbouring forest trees. The extent to which earlier developmental stages use the same or a distinctive suite of fungi was unclear. To address this question, a total of 1500 packets containing orchid seeds were buried for up to 3 years in diverse European forest sites which either supported or lacked populations of helleborine orchids. After harvest, the fungi associated with the three developmental stages, and with tree roots, were identified via cultivation-independent molecular methods. While our results show that most fungal symbionts are ectomycorrhizal, differences were observed between orchids in the representation of fungi at the three life stages. In Cephalanthera damasonium and C. longifolia, the fungi detected in seedlings were only a subset of the wider range seen in germinating seeds and mature plants. In Epipactis atrorubens, the fungi detected were similar at all three life stages, but different fungal lineages produced a difference in seedling germination performance. Our results demonstrate that there can be a narrow checkpoint for mycorrhizal range during seedling growth relative to the more promiscuous germination and mature stages of these plants' life cycle.

  14. Identification of bottlenecks for P450 biotransformation processes

    DEFF Research Database (Denmark)

    Andersson, Marie Therese; Törnvall, Ulrika; Tufvesson, Pär;

    Cytochrome P450 monooxygenases (P450 or CYP) is a group of heme-containing enzymes hydroxylating non-activated hydrocarbons in a stereospecific manner, something that is hard to achieve via classical chemistry. The importance of these reactions can be stressed by the hydroxylation of steroids, bu...

  15. From specification to measurement: the bottleneck in analog industrial testing

    NARCIS (Netherlands)

    Rijsinge, van R.J.; Haggenburg, A.A.R.M.; Vries, de C.; Wallinga, H.

    1990-01-01

    The translation of the specification of an analog device into the necessary set of measurements to be carried out by an industrial test facility is discussed. Algorithms are developed to compute the number of test vectors needed to guarantee a certain parameter and to compare several possible test m

  16. Breaking the biomass bottleneck of the fossil free society

    DEFF Research Database (Denmark)

    Wenzel, Henrik

    demand on food prices, namely the food crisis in 2007 – 2008. During this period, market prices on food and feed crops increased by almost a factor of 2, and the part of the world population suffering from hunger and starvation increased from 800 million to 900 million people. The amount of biomass...... grids and international trade will further assist in the balancing. But these measures are not enough. We still need high density fuels especially for aviation, but to some extent also for long distance, heavy transport on road and for sea transport. We also need carbon feedstock for our chemicals....... Through a process called hydrogenation it is possible to use biomass as a source of carbon and react hydrogen with it to produce hydrocarbons of much higher energy content and energy density than the original biomass. Moreover, using the biomass and the biogenic carbon from hydrogenation in central...

  17. Intelligent Automated Diagnosis of Client Device Bottlenecks in Private Clouds

    CERN Document Server

    Widanapathirana, C; Sekercioglu, Y A; Ivanovich, M; Fitzpatrick, P; 10.1109/UCC.2011.42

    2012-01-01

    We present an automated solution for rapid diagnosis of client device problems in private cloud environments: the Intelligent Automated Client Diagnostic (IACD) system. Clients are diagnosed with the aid of Transmission Control Protocol (TCP) packet traces, by (i) observation of anomalous artifacts occurring as a result of each fault and (ii) subsequent use of the inference capabilities of soft-margin Support Vector Machine (SVM) classifiers. The IACD system features a modular design and is extendible to new faults, with detection capability unaffected by the TCP variant used at the client. Experimental evaluation of the IACD system in a controlled environment demonstrated an overall diagnostic accuracy of 98%.

  18. Closed Queueing Networks Under Congestion: Nonbottleneck Independence and Bottleneck Convergence

    NARCIS (Netherlands)

    Anselmi, J.; D'Auria, B.; Walton, N.

    2013-01-01

    We analyze the behavior of closed multiclass product-form queueing networks when the number of customers grows to infinity and remains proportionate on each route (or class). First, we focus on the stationary behavior and prove the conjecture that the stationary distribution at nonbottleneck queues

  19. Caching Eliminates the Wireless Bottleneck in Video Aware Wireless Networks

    Directory of Open Access Journals (Sweden)

    Andreas F. Molisch

    2014-01-01

    Full Text Available Wireless video is the main driver for rapid growth in cellular data traffic. Traditional methods for network capacity increase are very costly and do not exploit the unique features of video, especially asynchronous content reuse. In this paper we give an overview of our work that proposed and detailed a new transmission paradigm exploiting content reuse and the widespread availability of low-cost storage. Our network structure uses caching in helper stations (femtocaching and/or devices, combined with highly spectrally efficient short-range communications to deliver video files. For femtocaching, we develop optimum storage schemes and dynamic streaming policies that optimize video quality. For caching on devices, combined with device-to-device (D2D communications, we show that communications within clusters of mobile stations should be used; the cluster size can be adjusted to optimize the tradeoff between frequency reuse and the probability that a device finds a desired file cached by another device in the same cluster. In many situations the network throughput increases linearly with the number of users, and the tradeoff between throughput and outage is better than in traditional base-station centric systems. Simulation results with realistic numbers of users and channel conditions show that network throughput can be increased by two orders of magnitude compared to conventional schemes.

  20. 影响高校思想政治理论课教学效果的瓶颈因素分析%Factors Attributing to the Bottleneck of the Teaching Effect of Courses about Ideological and Political Theory in Colleges and Universities

    Institute of Scientific and Technical Information of China (English)

    李光莉

    2012-01-01

    通过问卷调查发现高校思政课教学效果还有待改进,这与大学生对思政课教学内容的心理需要程度不很高有重要关系。从心理学角度分析,大学生对思政课教学内容的心理需要程度是影响其学习效果的重要制约因素,并据此认为,影响高校思政课教学效果的瓶颈是大学生的学习动机。为此,增强思政课教学效果,应注意提高大学生对思政课教学内容的心理需要程度,激发其学习动机,把思政课的"灌输"教学内容和学生心理"需要"内容结合起来,想方设法把"灌输内容"变为学生"需要内容"。%Through a questionnaire survey,we found that there is still some room for the improvement of the effect of ideological and political theory teaching,and this is involved with the lower extent of the psychological needs of college students for the teaching content.From a psychological point of view,the psychological needs of college students for the teaching content of the ideological and political theory affect their learning.As a result,it is quite obvious that the bottleneck impacting the teaching lies in students′ learning motivation.Enhancing the effect of ideological and political theory teaching should be guided by in ways:following raising students’ learning psychology,stimulating their learning motivation;unifying them by turning "content-instilling" to "content-seeking".

  1. A Research on the Sustainable Development of New Rural Cooperative Medical System:Constraining Bottleneck and Path Selection%新型农村合作医疗可持续发展研究:制约瓶颈与路径选择

    Institute of Scientific and Technical Information of China (English)

    李小芡

    2014-01-01

    China has launched the pilot work of new rural cooperative medical system since 2003. Basic medical services and alleviating farmers’ poverty due to illness become important institutional arrangements of building new socialist rural areas and coordinating urban and rural development. But design flaws of the new rural cooperative medical system, legisla-tive lags, imperfect financing mechanisms and not uniform operation modes have become the constraining bottleneck on the sustainable development of new rural cooperative medical system. The paper attaches great importance to system design, perfecting the targets of new rural cooperative medical system,accelerating legislative process,building scientific financing mechanisms, etc. The paper also proposes that the direction of the sustainable development of new rural cooperative medical system is to build urban and rural integration medical security system.%我国自2003年开始推行新农合试点工作,制度实施9年来,在保障农民获得基本医疗服务、缓解农民因病致贫、因病返贫中发挥着重要作用,成为建设社会主义新农村和统筹城乡发展的重要制度安排。但是新农合存在的制度设计缺陷、立法滞后、筹资机制不完善、运行模式不统一等问题已经成为制约新农合可持续的现实瓶颈,文章提出重视制度设计、完善新农合制度目标、加快立法进程、建立科学的筹资机制等措施,并认为最终实现建立城乡一体化的医疗保障制度是新农合可持续发展的方向。

  2. 优先数字出版:突破高校学报发展瓶颈的有效“武器”%The Priority of Digital Publishing:An Effective"Weapon"to Breakthrough the Bottleneck of the Development of University Journals

    Institute of Scientific and Technical Information of China (English)

    杨怀玫; 陈静

    2014-01-01

    在当今以网络技术为核心的信息时代,我国高校学报的发展普遍面临传播速度慢、载体单一、受众范围小,经济效益偏低等瓶颈问题。优先数字出版模式可突破高校学报发展的瓶颈,使其焕发活力,有效避免出版滞后、解决“一稿多投”,提高影响力、稳定作者群,加强竞争力、加大吸引力,以社会效益带动经济效益等优势。高校学报应转变思想观念,做好人力资源保障,严格遵守程序规范,做好后台技术保障等,确保高校学报优先数字出版平稳、有序地进行,促进高校学报的良性发展。%In the rapid information development today , network technology is at the core of the times , and the development of university journals in our country are featured by slow propagation velocity , single carrier, small audience -scope, low economic benefits.But the pattern of priority of digital publishing can breakthrough the bottleneck of the development of university journals , and revitalize them , such as a-voiding the publication hysteresis , multiple contributions .Besides , this pattern can enhance the influence factor, stable the author group , strengthen the competitiveness , increase the attraction……promote the so-cial economic benefits , etc.In order to promote the benign development , university journals themselves should do as the following:changing the ideas , doing a good job in human resources security , strictly a-biding by the standard procedures , having good technical background support , ensuring the priority of digital publishing .

  3. Addressing the medicinal chemistry bottleneck: a lean approach to centralized purification.

    Science.gov (United States)

    Weller, Harold N; Nirschl, David S; Paulson, James L; Hoffman, Steven L; Bullock, William H

    2012-09-10

    The use of standardized lean manufacturing principles to improve drug discovery productivity is often thought to be at odds with fostering innovation. This manuscript describes how selective implementation of a lean optimized process, in this case centralized purification for medicinal chemistry, can improve operational productivity and increase scientist time available for innovation. A description of the centralized purification process is provided along with both operational and impact (productivity) metrics, which indicate lower cost, higher output, and presumably more free time for innovation as a result of the process changes described.

  4. Bottlenecks in the development of topical analgesics: molecule, formulation, dose-finding, and phase III design

    Directory of Open Access Journals (Sweden)

    Keppel Hesselink JM

    2017-03-01

    Full Text Available Jan M Keppel Hesselink,1 David J Kopsky,2 Stephen M Stahl3 1Institute Neuropathic Pain, Bosch en Duin, the Netherlands; 2Institute Neuropathic Pain, Amsterdam, the Netherlands; 3University of California San Diego, La Jolla, CA, USA Abstract: Topical analgesics can be defined as topical formulations containing analgesics or co-analgesics. Since 2000, interest in such formulations has been on the rise. There are, however, four critical issues in the research and development phases of topical analgesics: 1 The selection of the active pharmaceutical ingredient. Analgesics and co-analgesics differ greatly in their mechanism of action, and it is required to find the most optimal fit between such mechanisms of action and the pathogenesis of the targeted (neuropathic pain. 2 Issues concerning the optimized formulation. For relevant clinical efficacy, specific characteristics for the selected vehicle (eg, cream base or gel base are required, depending on the physicochemical characteristics of the active pharmaceutical ingredient(s to be delivered. 3 Well-designed phase II dose-finding studies are required, and, unfortunately, such trials are missing. In fact, we will demonstrate that underdosing is one of the major hurdles to detect meaningful and statistically relevant clinical effects of topical analgesics. 4 Selection of clinical end points and innovatively designed phase III trials. End point selection can make or break a trial. For instance, to include numbness together with tingling as a composite end point for neuropathic pain seems stretching the therapeutic impact of an analgesic too far. Given the fast onset of action of topical analgesics (usually within 30 minutes, enrichment designs might enhance the chances for success, as the placebo response might decrease. Topical analgesics may become promising inroads for the treatment of neuropathic pain, once sufficient attention is given to these four key aspects. Keywords: topical, analgesics, cream, gel, dose-finding, formulation, ketamine, amitriptyline, baclofen, enrichment

  5. Lessons Learned From Microkernel Verification — Specification is the New Bottleneck

    Directory of Open Access Journals (Sweden)

    Thorsten Bormer

    2012-11-01

    Full Text Available Software verification tools have become a lot more powerful in recent years. Even verification of large, complex systems is feasible, as demonstrated in the L4.verified and Verisoft XT projects. Still, functional verification of large software systems is rare – for reasons beyond the large scale of verification effort needed due to the size alone. In this paper we report on lessons learned for verification of large software systems based on the experience gained in microkernel verification in the Verisoft XT project. We discuss a number of issues that impede widespread introduction of formal verification in the software life-cycle process.

  6. Development of a Workbench to Address the Educational Data Mining Bottleneck

    Science.gov (United States)

    Rodrigo, Ma. Mercedes T.; Baker, Ryan S. J. d.; McLaren, Bruce M.; Jayme, Alejandra; Dy, Thomas T.

    2012-01-01

    In recent years, machine-learning software packages have made it easier for educational data mining researchers to create real-time detectors of cognitive skill as well as of metacognitive and motivational behavior that can be used to improve student learning. However, there remain challenges to overcome for these methods to become available to…

  7. Scaling-up of membraneless microbial electrolysis cells (MECs) for domestic wastewater treatment: Bottlenecks and limitations.

    Science.gov (United States)

    Escapa, A; San-Martín, M I; Mateos, R; Morán, A

    2015-03-01

    Microbial electrolysis cells (MECs) have the potential to become a sustainable domestic wastewater (dWW) treatment system. However, new scale-up experiences are required to gain knowledge of critical issues in MEC designs. In this study we assess the ability of two twin membraneless MEC units (that are part of a modular pilot-scale MEC) to treat dWW. Batch tests yielded COD removal efficiencies as high as 92%, with most of the hydrogen (>80% of the total production) being produced during the first 48h. During the continuous tests, MECs performance deteriorated significantly (energy consumption was relatively high and COD removal efficiencies fell below 10% in many cases), which was attributed to an inadequate configuration of the anodic chamber, insufficient mixing inside this chamber, inefficient hydrogen management on the cathode side and finally to dWW in itself. Some alternatives to the current design are suggested.

  8. Looking through phonological shape to lexical meaning: the bottleneck of non-native sign language processing.

    Science.gov (United States)

    Mayberry, R I; Fischer, S D

    1989-11-01

    In two studies, we find that native and non-native acquisition show different effects on sign language processing. Subjects were all born deaf and used sign language for interpersonal communication, but first acquired it at ages ranging from birth to 18. In the first study, deaf signers shadowed (simultaneously watched and reproduced) sign language narratives given in two dialects, American Sign Language (ASL) and Pidgin Sign English (PSE), in both good and poor viewing conditions. In the second study, deaf signers recalled and shadowed grammatical and ungrammatical ASL sentences. In comparison with non-native signers, natives were more accurate, comprehended better, and made different kinds of lexical changes; natives primarily changed signs in relation to sign meaning independent of the phonological characteristics of the stimulus. In contrast, non-native signers primarily changed signs in relation to the phonological characteristics of the stimulus independent of lexical and sentential meaning. Semantic lexical changes were positively correlated to processing accuracy and comprehension, whereas phonological lexical changes were negatively correlated. The effects of non-native acquisition were similar across variations in the sign dialect, viewing condition, and processing task. The results suggest that native signers process lexical structural automatically, such that they can attend to and remember lexical and sentential meaning. In contrast, non-native signers appear to allocate more attention to the task of identifying phonological shape such that they have less attention available for retrieval and memory of lexical meaning.

  9. Bottlenecks and Multiple Introductions: Population Genetics of the Vector of Avian Malaria in Hawaii

    Science.gov (United States)

    2000-01-01

    extinction . Likewise, a high degree of genetic diversity in the parasite may hinder the development of resistance (May & Nowak 1994). Key in this...survive outside the mosquito zone. Although several factors may have contributed to the extinction and endangerment of the endemic species of...remote locations in the Big Island collected in hapuu cavities in the Hawaiian rainforest . Four unique haplotypes were found there. Overall, the low

  10. Recombinant plant-derived pharmaceutical proteins: current technical and economic bottlenecks.

    Science.gov (United States)

    Sabalza, Maite; Christou, Paul; Capell, Teresa

    2014-12-01

    Molecular pharming is a cost-effective platform for the production of recombinant proteins in plants. Although the biopharmaceutical industry still relies on a small number of standardized fermentation-based technologies for the production of recombinant proteins there is now a greater awareness of the advantages of molecular pharming particularly in niche markets. Here we discuss some of the technical, economic and regulatory barriers that constrain the clinical development and commercialization of plant-derived pharmaceutical proteins. We also discuss strategies to increase productivity and product quality/homogeneity. The advantages of whole plants should be welcomed by the industry because this will help to reduce the cost of goods and therefore expand the biopharmaceutical market into untapped sectors.

  11. Extreme genomic erosion after recurrent demographic bottlenecks in the highly endangered Iberian lynx

    DEFF Research Database (Denmark)

    Abascal, Federico; Corvelo, André; Cruz, Fernando;

    2016-01-01

    BACKGROUND: Genomic studies of endangered species provide insights into their evolution and demographic history, reveal patterns of genomic erosion that might limit their viability, and offer tools for their effective conservation. The Iberian lynx (Lynx pardinus) is the most endangered felid and...

  12. Is plasminogen activator inhibitor-1 a physiological bottleneck bridging major depressive disorder and cardiovascular disease?

    Science.gov (United States)

    Savoy, C; Van Lieshout, R J; Steiner, M

    2016-06-01

    Major depressive disorder (MDD) is estimated to affect one in twenty people worldwide. MDD is highly comorbid with cardiovascular disease (CVD), itself one of the single largest causes of mortality worldwide. A number of pathological changes observed in MDD are believed to contribute to the development of cardiovascular disease, although no single mechanism has been identified. There are also no biological markers capable of predicting the future risk of developing heart disease in depressed individuals. Plasminogen activator inhibitor-1 (PAI-1) is a prothrombotic plasma protein secreted by endothelial tissue and has long been implicated in CVD. An expanding body of literature has recently implicated it in the pathogenesis of major depressive disorder as well. In this study, we review candidate pathways implicating MDD in CVD and consider how PAI-1 might act as a mediator by which MDD induces CVD development: chiefly through sleep disruption, adiposity, brain-derived neurotrophic factor (BDNF) metabolism, systemic inflammation and hypothalamic-pituitary-adrenal (HPA)-axis dysregulation. As both MDD and CVD are more prevalent in women than in men, and incidence of either condition is dramatically increased during reproductive milestones, we also explore hormonal and sex-specific associations between MDD, PAI-1 and CVD. Of special interest is the role PAI-1 plays in perinatal depression and in cardiovascular complications of pregnancy. Finally, we propose a theoretical model whereby PAI-1 might serve as a useful biomarker for CVD risk in those with depression, and as a potential target for future treatments.

  13. The ambiguity of drought events, a bottleneck for Amazon forest drought response modelling

    Science.gov (United States)

    De Deurwaerder, Hannes; Verbeeck, Hans; Baker, Timothy; Christoffersen, Bradley; Ciais, Philippe; Galbraith, David; Guimberteau, Matthieu; Kruijt, Bart; Langerwisch, Fanny; Meir, Patrick; Rammig, Anja; Thonicke, Kirsten; Von Randow, Celso; Zhang, Ke

    2016-04-01

    Considering the important role of the Amazon forest in the global water and carbon cycle, the prognosis of altered hydrological patterns resulting from climate change provides strong incentive for apprehending the direct implications of drought on the vegetation of this ecosystem. Dynamic global vegetation models have the potential of providing a useful tool to study drought impacts on various spatial and temporal scales. This however assumes the models being able to properly represent drought impact mechanisms. But how well do the models succeed in meeting this assumption? Within this study meteorological driver data and model output data of 4 different DGVMs, i.e. ORCHIDEE, JULES, INLAND and LPGmL, are studied. Using the palmer drought severity index (PDSI) and the mean cumulative water deficit (MWD), temporal and spatial representation of drought events are studied in the driver data and are referenced to historical extreme drought events in the Amazon. Subsequently, within the resulting temporal and spatial frame, we studied the drought impact on the above ground biomass (AGB) and gross primary production (GPP) fluxes. Flux tower data, field inventory data and the JUNG data-driven GPP product for the Amazon region are used for validation. Our findings not only suggest that the current state of the studied DGVMs is inadequate in representing Amazon droughts in general, but also highlights strong inter-model differences in drought responses. Using scatterplot-studies and input-output correlations, we provide insight in the origin of these encountered inter-model differences. In addition, we present directives of model development and improvement in scope of Amazon forest drought response modelling.

  14. Flow rate of polygonal grains through a bottleneck: Interplay between shape and size

    Directory of Open Access Journals (Sweden)

    Ezequiel Goldberg

    2015-11-01

    Full Text Available We report two-dimensional simulations of circular and polygonal grains passing through an aperture at the bottom of a silo. The mass flow rate for regular polygons is lower than for disks\\red{,} as observed by other authors. We show that both the exit velocity of the grains and the packing fraction are lower for polygons, which leads to the reduced flow rate. We point out the importance of the criteria used to define when two objects of different shape are considered to be of the same size. Depending on this criteria, the mass flow rate may vary significantly for some polygons. Moreover, the particle flow rate is non-trivially related to a combination of mass flow rate, particle shape and particle size. For some polygons, the particle flow rate may be lower or higher than that of the corresponding disks depending on the size comparison criteria. Received: 18 May 2015, Accepted: 30 October 2015; Edited by: F. Melo; Reviewed by: J.-N. Roux, Universite Parsi Est, Laboratoire Navier, Champs-sur-Marne, France; DOI: http://dx.doi.org/10.4279/PIP.070016 Cite as: E Goldberg, C M Carlevaro, L A Pugnaloni, Papers in Physics 7, 070016 (2015

  15. Kinetic bottlenecks to chemical exchange rates for deep-sea animals - Part 2: Carbon Dioxide

    Science.gov (United States)

    Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

    2013-04-01

    Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc.) as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  16. Kinetic bottlenecks to chemical exchange rates for deep-sea animals II: Carbon dioxide

    Science.gov (United States)

    Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

    2012-11-01

    Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑CO2] etc.) as the critical variable and with a major focus on carbonate shell dissolution. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyze the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas since, as with gas exchange of CO2 at the air-sea interface, the influence of the ensemble of reactions within the CO2-HCO3--CO32- acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and flow rate under typical oceanic concentrations.The effect of these reactions can be described by an enhancement factor. For organisms, this means mechanically increasing flow over their surface to thin the boundary layer as is required to alleviate O2 stress seems not necessary to facilitate CO2 efflux. Nevertheless the elevated pCO2 cost most likely is non-zero. Regionally as with O2 the combination of T, P, and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth. But the net result is that, for the problem of gas exchange with the bulk ocean, the combination of an increasing T combined with declining O2 poses a greater challenge to marine life than does increasing CO2. The relationships developed here allow a more accurate prediction of the impacts on marine life from the combined effects of changing T, O2, and CO2 than can be estimated from single variable studies.

  17. Multitasking or Continuous Partial Attention: A Critical Bottleneck for Digital Natives

    Science.gov (United States)

    Firat, Mehmet

    2013-01-01

    With the beginning of the second half of the past century, advances in Information and Communication Technologies had unprecedented influence deeply felt in all social structures. The effects were so much widespread that the differences in technology use have created a huge gap between generations in terms of everyday life and lifestyle. As a…

  18. Are communities just bottlenecks? Trees and treelike networks have high modularity

    CERN Document Server

    Bagrow, James P

    2012-01-01

    Much effort has gone into understanding the modular nature of complex networks. Communities, also known as clusters or modules, are densely interconnected groups of nodes that are only sparsely connected to other groups in the network. Discovering high quality communities is a difficult and important problem in a number of areas. The most popular approach is the objective function known as Modularity, used to both discover communities and measure their strength. To understand the modular structure of networks it is then crucial to know how such functions evaluate different topologies, what features they account for and what implicit assumptions they may make. We show that trees and treelike networks can have unexpectedly and often arbitrarily high values of modularity. This is surprising since trees are maximally sparse connected graphs and are not typically considered to possess modular structure, yet the non-local null model used by modularity assigns low probabilities, and thus high significance, to the de...

  19. Bottlenecks in the prediction of regioselectivity of [4 + 2] cycloaddition reactions: An assessment of reactivity descriptors

    Indian Academy of Sciences (India)

    G Gayatri; G Narahari Sastry

    2005-09-01

    B3LYP/6-31G() calculations were performed to obtain all the transition states and products for the 128 distinct reaction channels of Diels-Alder reactions by taking all possible combinations from a series of dienes (1N-a, 1N-b, 2N, 1P-a, 1P-b, 2P, 1O, 1S) and dienophiles (NE, PE, OE, SE, AE, OHE, MeE, CNE). The predictive ability of the values to gauge the regioselectivity of the putative [4 + 2] cycloaddition reactions is analysed. No correlation is obtained between the reaction energies and activation energies. The extent of asynchronicity is measured based on the bond order analysis. DFT-based descriptors such as the local softness ($s^{+}_{k}$ and $s_{k}^{-}$), Fukui function indices ($f^{+}_{k}$ and $f_{k}^{-}$), global electrophilicity index () and local electrophilicity index () were found to be better than the conventional FMO predictions.

  20. Heterologous ectoine production in Escherichia coli: by-passing the metabolic bottle-neck.

    Science.gov (United States)

    Bestvater, Thorsten; Louis, Petra; Galinski, Erwin A

    2008-08-29

    Transcription of the ectoine biosynthesis genes ectA, ectB and ectC from Marinococcus halophilus in recombinant Escherichia coli DH5alpha is probably initiated from three individual sigma70/sigmaA-dependent promoter sequences, upstream of each gene. Consequently, mRNA-fragments containing the single genes and combinations of the genes ectA and ectB or ectB and ectC, respectively, could be detected by Northern blot analysis. Under the control of its own regulatory promoter region (ectUp) a seemingly osmoregulated ectoine production was observed. In addition, aspartate kinases were identified as the main limiting factor for ectoine production in recombinant E. coli DH5alpha. Co-expression of the ectoine biosynthesis genes and of the gene of the feedback-resistant aspartate kinase from Corynebacterium glutamicum MH20-22B (lysC) led to markedly increased production of ectoine in E. coli DH5alpha, resulting in cytoplasmic ectoine concentrations comparable to those reached via ectoine accumulation from the medium.

  1. MULTITASKING OR CONTINUOUS PARTIAL ATTENTION: A CRITICAL BOTTLENECK FOR DIGITAL NATIVES

    Directory of Open Access Journals (Sweden)

    Mehmet FIRAT

    2013-01-01

    Full Text Available With the beginning of the second half of the past century, advances in Information and Communication Technologies had unprecedented influence deeply felt in all social structures. The effects were so much widespread that the differences in technology use have created a huge gap between generations in terms of everyday life and lifestyle. As a result, two groups occurred; those growing with technology digital natives and digital immigrants who try to keep pace with technology. Today, the computer, internet and mobile technologies like e-book readers, mobile phones, android devices, smart phones and tablet computers have become all-day business and communication tools used by digital natives. However, these high-tech tools, with their speed and ease of use, revealed some important issues that deeply affect digital natives' way of life. Among these most important effects are Continuous Partial Attention and Multitasking. In this study, these two conditions faced by digital natives were compared, and some suggestions have been put forward for the digital native learners.

  2. Kinetic bottlenecks to chemical exchange rates for deep-sea animals – Part 1: Oxygen

    Directory of Open Access Journals (Sweden)

    E. T. Peltzer

    2012-10-01

    Full Text Available Ocean warming will reduce dissolved oxygen concentrations which can pose challenges to marine life. Oxygen limits are traditionally reported simply as a static concentration thresholds with no temperature, pressure or flow rate dependency. Here we treat the oceanic oxygen supply potential for heterotrophic consumption as a dynamic molecular exchange problem analogous to familiar gas exchange processes at the sea surface. A combination of the purely physico-chemical oceanic properties temperature, hydrostatic pressure, and oxygen concentration defines the ability of the ocean to supply oxygen to any given animal. This general oceanic oxygen supply potential is modulated by animal specific properties such as the diffusive boundary layer thickness to define and limit maximal oxygen supply rates. Here we combine all these properties into formal, mechanistic equations defining novel oceanic properties that subsume various relevant classical oceanographic parameters to better visualize, map, comprehend, and predict the impact of ocean deoxygenation on aerobic life. By explicitly including temperature and hydrostatic pressure into our quantities, various ocean regions ranging from the cold deep-sea to warm, coastal seas can be compared. We define purely physico-chemical quantities to describe the oceanic oxygen supply potential, but also quantities that contain organism-specific properties which in a most generalized way describe general concepts and dependencies. We apply these novel quantities to example oceanic profiles around the world and find that temperature and pressure dependencies of diffusion and partial pressure create zones of greatest physical constriction on oxygen supply typically at around 1000 m depth, which coincides with oxygen concentration minimum zones. In these zones, which comprise the bulk of the world ocean, ocean warming and deoxygenation have a clear negative effect for aerobic life. In some shallow and warm waters the enhanced diffusion and higher partial pressure due to higher temperatures might slightly overcompensate for oxygen concentration decreases due to decreases in solubility.

  3. Bottlenecks in the Efficient Use of Advanced Therapy Medicinal Products Based on Mesenchymal Stromal Cells

    Directory of Open Access Journals (Sweden)

    Natalia Escacena

    2015-01-01

    Full Text Available Mesenchymal stromal cells (MSCs have been established as promising candidate sources of universal donor cells for cell therapy due to their contributions to tissue and organ homeostasis, repair, and support by self-renewal and multidifferentiation, as well as by their anti-inflammatory, antiproliferative, immunomodulatory, trophic, and proangiogenic properties. Various diseases have been treated by MSCs in animal models. Additionally, hundreds of clinical trials related to the potential benefits of MSCs are in progress. However, although all MSCs are considered suitable to exert these functions, dissimilarities have been found among MSCs derived from different tissues. The same levels of efficacy and desired outcomes have not always been achieved in the diverse studies that have been performed thus far. Moreover, autologous MSCs can be affected by the disease status of patients, compromising their use. Therefore, collecting information regarding the characteristics of MSCs obtained from different sources and the influence of the host (patient medical conditions on MSCs is important for assuring the safety and efficacy of cell-based therapies. This review provides relevant information regarding factors to consider for the clinical application of MSCs.

  4. Bottlenecks in the Efficient Use of Advanced Therapy Medicinal Products Based on Mesenchymal Stromal Cells.

    Science.gov (United States)

    Escacena, Natalia; Quesada-Hernández, Elena; Capilla-Gonzalez, Vivian; Soria, Bernat; Hmadcha, Abdelkrim

    2015-01-01

    Mesenchymal stromal cells (MSCs) have been established as promising candidate sources of universal donor cells for cell therapy due to their contributions to tissue and organ homeostasis, repair, and support by self-renewal and multidifferentiation, as well as by their anti-inflammatory, antiproliferative, immunomodulatory, trophic, and proangiogenic properties. Various diseases have been treated by MSCs in animal models. Additionally, hundreds of clinical trials related to the potential benefits of MSCs are in progress. However, although all MSCs are considered suitable to exert these functions, dissimilarities have been found among MSCs derived from different tissues. The same levels of efficacy and desired outcomes have not always been achieved in the diverse studies that have been performed thus far. Moreover, autologous MSCs can be affected by the disease status of patients, compromising their use. Therefore, collecting information regarding the characteristics of MSCs obtained from different sources and the influence of the host (patient) medical conditions on MSCs is important for assuring the safety and efficacy of cell-based therapies. This review provides relevant information regarding factors to consider for the clinical application of MSCs.

  5. Dispersal and colonisation of plants in lowland streams: success rates and bottlenecks

    DEFF Research Database (Denmark)

    Riis, Tenna

    2008-01-01

    Plant dispersal and colonisation, including rates of dispersal, retention, colonisation and survival of dispersed propagules (shoots and seeds), were studied in a 300-m stream reach in a macrophyte-rich lowland stream during one growing season. Relationships between colonisation processes...... and seeds, due in part to low retention success (1% of the dispersed shoots per 100-m reach) and to unsuccessful colonisation of retained shoots (3.4% of retained shoots colonised). The number of drifting shoots and seeds per day during the growing season were 650-6,950 and 2,970-62,780, respectively...... and simple flow parameters were tested. Each fortnight during a growing season, the number of dispersed plant propagules and the number of new and lost plant colonisations since the last sampling day were recorded. The retention of dispersing shoots was tested on two occasions during the growing season...

  6. Bottlenecks in the transmission of antibiotic resistance from natural ecosystems to human bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jose L Martinez

    2012-01-01

    Full Text Available It is generally accepted that resistance genes acquired by human pathogens trough horizontal gene transfer have been originated in environmental, non pathogenic bacteria. As the consequence, there exists an increasing concern on the role that natural, non-clinical ecosystems, may play on the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance upon their expression in a heterologous host is much larger than what is actually found in human pathogens. Along the review, the role that different processes as founder effect, ecological connectivity, fitness costs or second-order selection may have on the establishment of a specific resistance determinant in the population of bacterial pathogens is analysed.

  7. Bottlenecks in the Transferability of Antibiotic Resistance from Natural Ecosystems to Human Bacterial Pathogens

    OpenAIRE

    Martínez, José L.

    2012-01-01

    It is generally accepted that resistance genes acquired by human pathogens through horizontal gene transfer originated in environmental, non-pathogenic bacteria. As a consequence, there is increasing concern on the roles that natural, non-clinical ecosystems, may play in the evolution of resistance. Recent studies have shown that the variability of determinants that can provide antibiotic resistance on their expression in a heterologous host is much larger than what is actually found in human...

  8. GWDC Solves World-class Drilling Bottleneck in Kenkijak Oil Field

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The news that Greatwall Drilling Company Limited (GWDC) has drilled a well with the daily oil production of more than one thousand tons spread quickly when the Well H8010 of CNPC Aktobin Oil and Gas Shareholding Company (CNPC Aktobin) in Kenkijak Oil Field in Kazakhstan produced 1,170 tons on July 1, 2004; both the employees of GWDC and CNPC Aktobin could not hold their excited feeling and cheered at such encouraging news.

  9. A recent bottleneck of Y chromosome diversity coincides with a global change in culture

    DEFF Research Database (Denmark)

    Monika, Karmin; Saag, Lauri; Vicente, Mario;

    2015-01-01

    It is commonly thought that human genetic diversity in non-African populations was shaped primarily by an out-of-Africa dispersal 50-100 thousand yr ago (kya). Here, we present a study of 456 geographically diverse high-coverage Y chromosome sequences, including 299 newly reported samples. Applyi...

  10. Costa Rica, superstar? some reflections on the global drivers and bottlenecks of the happy planet index

    OpenAIRE

    Tausch, Arno

    2011-01-01

    For some years now, the Happy Planet Organization presents the so-called ‘Happy Planet Index’ (HPI), which is an index of measuring the trade-off between ecological footprint data and life quality (Happy Life Years, HLYE). Costa Rica emerges from these comparisons as the world’s ‘best practice nation’, using a minimum amount of natural resources to achieve a maximum of human happiness. So is Costa Rica the pathway for humanity? There are shortcomings in the formula, with which the index is ca...

  11. Globalization as a driver or bottleneck for sustainable development. General tendencies and European implications

    OpenAIRE

    Tausch, Arno

    2011-01-01

    This article looks at the long-term, structural determinants of environmental performance in the world system. In multiple standard OLS regression models, we test the effects of 26 standard predictor variables, including the ‘four freedoms’ of goods, capital, labour and services, on the following indicators of sustainable development • avoiding net trade of ecological footprint gha per person • Carbon emissions per million US dollars GDP • CO2 per capita • Environmental Performa...

  12. Dynamic bottleneck optimization for k-edge and 2-vertex connectivity

    DEFF Research Database (Denmark)

    Telelis, Orestis; Zissimopoulos, Vassilis

    2008-01-01

    We consider the problem of updating efficiently the minimum value b over a weighted graph, so that edges with a cost less than b induce a spanning subgraph satisfying a k-edge or 2-vertex connectivity constraint, when the cost of an edge of the graph is updated. Our results include update...

  13. Performance Modeling of a Bottleneck Node in an IEEE 802.11 Ad-hoc Network

    NARCIS (Netherlands)

    Berg, van den Hans; Roijers, Frank; Mandjes, Michel R.H.; Kunz, T.; Ravi, S.S.

    2006-01-01

    The IEEE 802.11 MAC protocol, often used in ad-hoc networks, has the tendency to share the capacity equally amongst the active nodes, irrespective of their loads. An inherent drawback of this fair-sharing policy is that a node that serves as a relay-node for multiple flows is likely to become a bott

  14. Performance modelieg of a bottleneck node in an IEEE 802.11 ad-hoc network

    NARCIS (Netherlands)

    Berg, J.L. van den; Mandjes, M.; Roijers, F.

    2006-01-01

    The IEEE 802.11 MAC-protocol, often used in ad-hoc networks, has the tendency to share the capacity equally amongst the active nodes, irrespective of their loads. An inherent drawback of this fair-sharing policy is that a node that serves as a relay-node for multiple flows is likely to become a bott

  15. Beneficial Effects of Population Bottlenecks in an RNA Virus Evolving at Increased Error Rate

    OpenAIRE

    Cases-González, Clara E.; Arribas, María; Domingo, Esteban; Lázaro, Ester

    2008-01-01

    RNA viruses replicate their genomes with a very high error rate and constitute highly heterogeneous mutant distributions similar to the molecular quasispecies introduced to explain the evolution of prebiotic replicators. The genetic information included in a quasispecies can only be faithfully transmitted below a critical error rate. When the error threshold is crossed, the population structure disorganizes, and it is substituted by a randomly distributed mutant spectrum. For viral quasispeci...

  16. Out of the bottleneck: the Diversity Outcross and Collaborative Cross mouse populations in behavioral genetics research.

    Science.gov (United States)

    Chesler, Elissa J

    2014-02-01

    The historical origins of classical laboratory mouse strains have led to a relatively limited range of genetic and phenotypic variation, particularly for the study of behavior. Many recent efforts have resulted in improved diversity and precision of mouse genetic resources for behavioral research, including the Collaborative Cross and Diversity Outcross population. These two populations, derived from an eight way cross of common and wild-derived strains, have high precision and allelic diversity. Behavioral variation in the population is expanded, both qualitatively and quantitatively. Variation that had once been canalized among the various inbred lines has been made amenable to genetic dissection. The genetic attributes of these complementary populations, along with advances in genetic and genomic technologies, makes a systems genetic analyses of behavior more readily tractable, enabling discovery of a greater range of neurobiological phenomena underlying behavioral variation.

  17. Heterologous ectoine production in Escherichia coli: By-passing the metabolic bottle-neck

    OpenAIRE

    Bestvater, Thorsten; Louis, Petra; Galinski, Erwin A.

    2008-01-01

    Transcription of the ectoine biosynthesis genes ectA, ectB and ectC from Marinococcus halophilus in recombinant Escherichia coli DH5α is probably initiated from three individual σ70/σA-dependent promoter sequences, upstream of each gene. Consequently, mRNA-fragments containing the single genes and combinations of the genes ectA and ectB or ectB and ectC, respectively, could be detected by Northern blot analysis. Under the control of its own regulatory promoter region (ectUp) a seemingly osmor...

  18. Heterologous ectoine production in Escherichia coli: By-passing the metabolic bottle-neck

    Science.gov (United States)

    Bestvater, Thorsten; Louis, Petra; Galinski, Erwin A

    2008-01-01

    Transcription of the ectoine biosynthesis genes ectA, ectB and ectC from Marinococcus halophilus in recombinant Escherichia coli DH5α is probably initiated from three individual σ70/σA-dependent promoter sequences, upstream of each gene. Consequently, mRNA-fragments containing the single genes and combinations of the genes ectA and ectB or ectB and ectC, respectively, could be detected by Northern blot analysis. Under the control of its own regulatory promoter region (ectUp) a seemingly osmoregulated ectoine production was observed. In addition, aspartate kinases were identified as the main limiting factor for ectoine production in recombinant E. coli DH5α. Co-expression of the ectoine biosynthesis genes and of the gene of the feedback-resistant aspartate kinase from Corynebacterium glutamicum MH20-22B (lysC) led to markedly increased production of ectoine in E. coli DH5α, resulting in cytoplasmic ectoine concentrations comparable to those reached via ectoine accumulation from the medium. PMID:18759971

  19. Meta-Analysis of Mitochondrial DNA Reveals Several Population Bottlenecks during Worldwide Migrations of Cattle

    Directory of Open Access Journals (Sweden)

    Johannes A. Lenstra

    2014-03-01

    Full Text Available Several studies have investigated the differentiation of mitochondrial DNA in Eurasian, African and American cattle as well as archaeological bovine material. A global survey of these studies shows that haplogroup distributions are more stable in time than in space. All major migrations of cattle have shifted the haplogroup distributions considerably with a reduction of the number of haplogroups and/or an expansion of haplotypes that are rare or absent in the ancestral populations. The most extreme case is the almost exclusive colonization of Africa by the T1 haplogroup, which is rare in Southwest Asian cattle. In contrast, ancient samples invariably show continuity with present-day cattle from the same location. These findings indicate strong maternal founder effects followed by limited maternal gene flow when new territories are colonized. However, effects of adaptation to new environments may also play a role.

  20. Kinetic bottlenecks to chemical exchange rates for deep-sea animals – Part 2: Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2013-04-01

    Full Text Available Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc. as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  1. Kinetic bottlenecks to chemical exchange rates for deep-sea animals II: Carbon dioxide

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2012-11-01

    Full Text Available Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑CO2] etc. as the critical variable and with a major focus on carbonate shell dissolution. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyze the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas since, as with gas exchange of CO2 at the air-sea interface, the influence of the ensemble of reactions within the CO2-HCO3-CO32– acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and flow rate under typical oceanic concentrations.The effect of these reactions can be described by an enhancement factor. For organisms, this means mechanically increasing flow over their surface to thin the boundary layer as is required to alleviate O2 stress seems not necessary to facilitate CO2 efflux. Nevertheless the elevated pCO2 cost most likely is non-zero. Regionally as with O2 the combination of T, P, and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth. But the net result is that, for the problem of gas exchange with the bulk ocean, the combination of an increasing T combined with declining O2 poses a greater challenge to marine life than does increasing CO2. The relationships developed here allow a more accurate prediction of the impacts on marine life from the combined effects of changing T, O2, and CO2 than can be estimated from single variable studies.

  2. Meta-Analysis of mitochondrial DNA reveals several population bottlenecks during worldwide migrations of cattle

    NARCIS (Netherlands)

    Lenstra, Johannes A.; Ajmone-Marsan, Paolo; Beja-Pereira, Albano; Bollongino, Ruth; Bradley, Daniel G.; Colli, Licia; De Gaetano, Anna; Edwards, Ceiridwen J.; Felius, Marleen; Ferretti, Luca; Ginja, Catarina; Hristov, Peter; Kantanen, Juha; Lirón, Juan Pedro; Magee, David A.; Negrini, Riccardo; Radoslavov, Georgi A.

    2014-01-01

    Several studies have investigated the differentiation of mitochondrial DNA in Eurasian, African and American cattle as well as archaeological bovine material. A global survey of these studies shows that haplogroup distributions are more stable in time than in space. All major migrations of cattle ha

  3. Processes for non-destructive transfer of graphene: widening the bottleneck for industrial scale production.

    Science.gov (United States)

    Zaretski, Aliaksandr V; Lipomi, Darren J

    2015-06-14

    The exceptional charge-transport, mechanical, and barrier properties of graphene are well known. High-quality films of single-layer graphene produced over large areas, however, are extremely expensive. The high cost of graphene precludes its use in industries-such as transparent electrodes and flexible packaging-that might take full advantage of its properties. This minireview presents several strategies for the transfer of graphene from the substrates used for growth to substrates used for the final application. Each strategy shares the characteristic of being non-destructive: that is, the growth substrate remains reusable for further synthesis of new graphene. These processes have the potential to lower significantly the costs of manufacturing graphene, to increase production yields, and to minimize environmental impact. This article is divided into sections on (i) the synthesis of high-quality single-layer graphene and (ii) its non-destructive transfer to a host substrate. Section (ii) is further divided according to the substrate from which graphene is transferred: single-crystalline wafers or flexible copper foils. We also comment, wherever possible, on defects produced as a result of the transfer, and potential strategies to mitigate these defects. We conclude that several methods for the green synthesis and transfer of graphene have several of the right characteristics to be useful in industrial scale production.

  4. Advances and bottlenecks in modelling the greenhouse climate: summary of a group discussion

    NARCIS (Netherlands)

    Seginer, I.; Bakker, J.C.

    1998-01-01

    This report is a summary of a group discussion at the symposium 'Models in protected cultivation' held in Wageningen, August 1997. The discussion focused on the reasons for the relatively limited acceptance and application of greenhouse climate models, especially in commercial practice. The discussi

  5. 论瓶颈垄断%On Bottle-Neck Monopoly

    Institute of Scientific and Technical Information of China (English)

    刘伟

    2002-01-01

    本文在对瓶颈垄断及其有关概念解释的基础上,分析了瓶颈垄断原则适用的经济学理论依据,并介绍了美国反托拉斯法的瓶颈垄断规制原则的演变和发展。本文认为在传统的自然垄断行业放松管制、引入竞争的大趋势下,引入瓶颈垄断原则是我国反垄断立法的正确选择,同时要正确处理好管制行业的直接管制和反垄断法间接规制的关系。

  6. Overcoming the bottlenecks of anaerobic digestion of olive mill solid waste by two-stage fermentation.

    Science.gov (United States)

    Stoyanova, Elitza; Lundaa, Tserennyam; Bochmann, Günther; Fuchs, Werner

    2017-02-01

    Two-stage anaerobic digestion (AD) of two-phase olive mill solid waste (OMSW) was applied for reducing the inhibiting factors by optimizing the acidification stage. Single-stage AD and co-fermentation with chicken manure were conducted coinstantaneous for direct comparison. Degradation of the polyphenols up to 61% was observed during the methanogenic stage. Nevertheless the concentration of phenolic substances was still high; the two-stage fermentation remained stable at OLR 1.5 kgVS/m³day. The buffer capacity of the system was twice as high, compared to the one-stage fermentation, without additives. The two-stage AD was a combined process - thermophilic first stage and mesophilic second stage, which pointed out to be the most profitable for AD of OMSW for the reduced hydraulic retention time (HRT) from 230 to 150 days, and three times faster than the single-stage and the co-fermentation start-up of the fermentation. The optimal HRT and incubation temperature for the first stage were determined to four days and 55°C. The performance of the two-stage AD concerning the stability of the process was followed by the co-digestion of OMSW with chicken manure as a nitrogen-rich co-substrate, which makes them viable options for waste disposal with concomitant energy recovery.

  7. Bottlenecks and Spatiotemporal variation in the sexual reproduction pathway of perennial meadow plants.

    NARCIS (Netherlands)

    Jongejans, E.; Soons, M.B.; Kroon, de H.

    2006-01-01

    Sexual reproduction is important for the growth of populations and the maintenance of genetic diversity. Several steps are involved in the sexual reproduction pathway of plants: the production of flowers, the production of seeds and the establishment of seedlings from seeds. In this paper we quantif

  8. Surviving in changing seascapes : Sediment dynamics as bottleneck for long-term seagrass presence

    NARCIS (Netherlands)

    Suykerbuyk, Wouter; Bouma, Tjeerd J.; Govers, Laura L.; Giesen, Kris; de Jong, Dick J.; Herman, Peter; Hendriks, Jan; van Katwijk, Marieke M.

    2016-01-01

    Changes in the seascape often result in altered hydrodynamics that lead to coinciding changes in sediment dynamics. Little is known on how altered sediment dynamics affect long-term seagrass persistence. We studied the thresholds of sediment dynamics in relation to seagrass presence by comparing sed

  9. Surviving in Changing Seascapes: Sediment Dynamics as Bottleneck for Long-Term Seagrass Presence

    NARCIS (Netherlands)

    Suykerbuyk, W.; Bouma, T.J.; Govers, L.L.; Giesen, K.; de Jong, D.J.; Herman, P.M.J.; Hendriks, J.; van Katwijk, M.M.

    2016-01-01

    Changes in the seascape often result in altered hydrodynamics that lead to coinciding changes in sediment dynamics. Little is known on how altered sediment dynamics affect long-term seagrass persistence. We studied the thresholds of sediment dynamics in relation to seagrass presence by comparing sed

  10. Photosynthesis driven crop growth models for greenhouse cultivation; advances and bottlenecks.

    NARCIS (Netherlands)

    Challa, H.; Heuvelink, E.

    1996-01-01

    In recent years considerable progress has been made in modelling growth of green-house crops. Nevertheless, the share of research in this field compared to crop modelling in general is only a few percent. Yet, crop growth models have a great potential for greenhouse production systems, because they

  11. Land, Fund and Mechanism: Three Bottlenecks of Chinese Urban Forestry in the 21st Century

    Institute of Scientific and Technical Information of China (English)

    LIU Deliang; LI jiyue; ZUO Jiafu

    2006-01-01

    Although desirable developments have been achieved since the implementation of the reform-and-opening-up policy, the urban forestry in China is still haunted by the problems of land scarcity, fund shortage and administrative mechanism dysfunction. With a concern of these problems, this paper have made a survey of the current status of the land use in urban areas for the purpose of proposing strategies for urban forestry development in China, and have made an evaluation on the relation between fund and urban forestry with a focus on the means of attracting investment and raising fund. In line with the system of social organizations, of administration, and of management, special concern about the systematic and operational mechanism of urban forestry has been expressed. Based upon the analysis as such, this paper holds that land is the foundation of urban forestry development; fund is the motive force of the sustainable development of urban forestry; mechanism is the guarantee for the urban forestry to develop in a healthy and effective order.

  12. Topological-based bottleneck analysis and improvement strategies for traffic networks

    Institute of Scientific and Technical Information of China (English)

    WU JianJun; GAO ZiYou; SUN HuiJun

    2009-01-01

    ck,and make appropriate policies for traffic demand management.Meanwhile,the method has very important theoretical significance and practical worthiness in optimizing traffic organization,traffic control,and disposal of emergency.

  13. High conductivity organic thin films for spintronics: the interface resistance bottleneck.

    Science.gov (United States)

    Zanettini, S; Chaumy, G; Chávez, P; Leclerc, N; Etrillard, C; Leconte, B; Chevrier, F; Dayen, J-F; Doudin, B

    2015-11-25

    Highly electrochemically doped poly(2,5-bis(3-dodecyl-2-yl)-thieno[3,2-b]thiophene (pBTTT) thin films exhibiting remarkably high conductivities values reaching 3000-5000 Ω(-1) cm(-1) are investigated. Experimental evidence of delocalized transport properties of this material at the onset of metallicity makes it an ideal candidate for spin valve device integration. Nevertheless, the interface resistance between the polymer and metallic electrodes is orders of magnitudes larger than the expected spin resistance of the active channel. This prevents the collection of a spin current. This finding can explain the lack of success in making lateral organic spin valves reported in the literature, especially the related absence of spin signals in non-local spin valve and Hanle current measurements in organic thin films.

  14. Relative quantification in seed GMO analysis: state of art and bottlenecks.

    Science.gov (United States)

    Chaouachi, Maher; Bérard, Aurélie; Saïd, Khaled

    2013-06-01

    Reliable quantitative methods are needed to comply with current EU regulations on the mandatory labeling of genetically modified organisms (GMOs) and GMO-derived food and feed products with a minimum GMO content of 0.9 %. The implementation of EU Commission Recommendation 2004/787/EC on technical guidance for sampling and detection which meant as a helpful tool for the practical implementation of EC Regulation 1830/2003, which states that "the results of quantitative analysis should be expressed as the number of target DNA sequences per target taxon specific sequences calculated in terms of haploid genomes". This has led to an intense debate on the type of calibrator best suitable for GMO quantification. The main question addressed in this review is whether reference materials and calibrators should be matrix based or whether pure DNA analytes should be used for relative quantification in GMO analysis. The state of the art, including the advantages and drawbacks, of using DNA plasmid (compared to genomic DNA reference materials) as calibrators, is widely described. In addition, the influence of the genetic structure of seeds on real-time PCR quantitative results obtained for seed lots is discussed. The specific composition of a seed kernel, the mode of inheritance, and the ploidy level ensure that there is discordance between a GMO % expressed as a haploid genome equivalent and a GMO % based on numbers of seeds. This means that a threshold fixed as a percentage of seeds cannot be used as such for RT-PCR. All critical points that affect the expression of the GMO content in seeds are discussed in this paper.

  15. Why do organizations not learn from incidents? Bottlenecks, causes and conditions for a failure to effectively learn

    NARCIS (Netherlands)

    Drupsteen, L.; Hasle, P.

    2014-01-01

    If organizations would be able to learn more effectively from incidents that occurred in the past, future incidents and consequential injury or damage can be prevented. To improve learning from incidents, this study aimed to identify limiting factors, i.e. the causes of the failure to effectively le

  16. Identification and Reduction of Bottlenecks Concerning MICAP Re-Supply of F-16 Weapons System Avionics Line Replaceable Units

    Science.gov (United States)

    1997-09-01

    developed by Eliyahu Goldratt ], is a continual improvement philosophy that focuses on the identification and management of constraints for organizational...FedEx U.S. Government Contract Services Guide. August 1996. 51 Goldratt , Eliyahu M. The Goal: A Process of Ongoing Improvement. Second Edition. North

  17. Bottlenecks in bog pine multiplication by somatic embryogenesis and their visualization with the environmental scanning electron microscope.

    Science.gov (United States)

    Vlašínová, Helena; Neděla, Vilem; Đorđević, Biljana; Havel, Ladislav

    2016-10-25

    Somatic embryogenesis (SE) is an important biotechnological technique used for the propagation of many pine species in vitro. However, in bog pine, one of the most endangered tree species in the Czech Republic, limitations were observed, which negatively influenced the development and further germination of somatic embryos. Although initiation frequency was very low-0.95 %, all obtained cell lines were subjected to maturation. The best responding cell line (BC1) was used and subjected to six different variants of the maturation media. The media on which the highest number of early-precotyledonary/cotyledonary somatic embryos was formed was supplemented with 121 μM abscisic acid (ABA) and with 6 % maltose. In the end of maturation experiments, different abnormalities in formation of somatic embryos were observed. For visualization and identification of abnormalities in meristem development during proliferation and maturation processes, the environmental scanning electron microscope was used. In comparison to the classical light microscope, the non-commercial environmental scanning electron microscope AQUASEM II has been found as a very useful tool for the quick recognition of apical meristem disruption and abnormal development. To our knowledge, this is the first report discussing somatic embryogenesis in bog pine. Based on this observation, the cultivation procedure could be enhanced and the method for SE of bog pine optimized.

  18. Characterizing topological bottlenecks for data delivery in CTP using simulation-based stress testing with natural selection

    NARCIS (Netherlands)

    Bucur, Doina; Iacca, Giovanni; Boer, de Pieter-Tjerk

    2015-01-01

    Routing protocols for ad-hoc networks, e.g., the Collection Tree Protocol (CTP), are designed with simple node-local behaviour, but are deployed on testbeds with uncontrollable physical topology; exhaustively verifying the protocol on all possible topologies at design time is not tractable. We obtai

  19. The Jaramillo Bottleneck for Migration of Hominins with Megaherbivores Into Europe via the Danube-Po Gateway

    Science.gov (United States)

    Muttoni, G.; Kent, D. V.; Scardia, G.

    2015-12-01

    Based on ongoing magnetostratigraphic work and updated critical reviews of sites bearing hominin remains and/or tools from greater Europe, including the Balkans and Greece, we maintain that the only compelling evidence of hominin presence in these regions was after the Jaramillo subchron (0.99 Ma), at about the time of the climatic late Early Pleistocene revolution (EPR) and the onset of enhanced glacial/interglacial activity from MIS 22 onward. Europe may have become initially populated during the EPR when, possibly for the first time in the Pleistocene, vast and exploitable ecosystems were generated along the Danube-Po Gateway in the Balkan peninsula and northern Italy. These newly formed settings, characterized by low-lands with open grasslands and reduced woody cover during glacial/interglacial transitions, represented the closest analogues to the savanna environment to which several large mammals linked with hominins in a common food web were adapted and could use as a migratory corridor. We acknowledge that lack of evidence may not be a compelling argument, but the absence of the Jaramillo and out-of-sequence cosmogenic nuclide dates with wide error margins in key sections preclude the use of such evidence to substantiate the presence of humans (and presumably associated biostratigraphic markers) prior to the Jaramillo, and thus logically deny applying such conclusions to other systems.

  20. A control method for congested traffic induced by bottlenecks in the coupled map car-following model

    Science.gov (United States)

    Zhao, Xiaomei; Gao, Ziyou

    2006-07-01

    We present a simple control method to suppress the traffic congestion in the coupled map car-following model under open boundary, based on the pioneer work of Konishi et al. [Coupled map car-following model and its delayed-feedback control, Phys. Rev. E 60 (1999) 4000-4007]. Theoretically, it is proven that the congested traffic in the traffic system could be suppressed by using the method. Comparison between our method and the method of Konishi et al. is carried out. The simulation results show the temporal behavior obtained by our method is better than that by the method of Konishi et al., although both the methods can suppress the traffic jam. The simulation results demonstrate that the traffic system can move into a homogeneous phase and the flux has great increases by the introduction of the control signal. The simulation results are in good agreement with the theoretical analysis.

  1. Risk-Control Approach for a Bottleneck Spanning Tree Problem with the Total Network Reliability under Uncertainty

    Directory of Open Access Journals (Sweden)

    Takashi Hasuike

    2012-01-01

    parameters to edge costs is introduced as objective functions in the risk-control. Furthermore, in order to maintain the constructing spanning tree network entirely, the reliability for each edge is introduced, and maximizing the total reliability of spanning tree is assumed as the third objective function. The proposed model is a multiobjective programming problem, and hence, it is difficult to solve it directly without setting some optimal criterion. Therefore, satisfaction functions for each object and the integrated function are introduced, and the exact solution algorithm is developed by performing deterministic equivalent transformations. A numerical example is provided by comparing our proposed model with previous standard models.

  2. Could nutrition sensitive cocoa value chains be introduced in Ghana? Report of a brief study that identifies opportunities and bottlenecks

    NARCIS (Netherlands)

    Vries, de K.

    2015-01-01

    This study looks at whether introducing nutrition sensitive cocoa value chains in Ghana is feasible and recommends how this could be done. After establishing the cocoa farming and nutrition context in Ghana, the study zooms in on one cocoa producing sub-district to collect detailed data in order to

  3. The rate of food processing in the Oystercatcher : Food intake and energy expenditure constrained by a digestive bottleneck

    NARCIS (Netherlands)

    Kersten, M

    1996-01-01

    1. Whether food intake is determined by the maximum rate at which animals can collect food, or by the rate at which this food can be processed, will strongly affect the organization of their behaviour. We investigated whether the digestive system imposes a constraint on (I) instantaneous rate of foo

  4. Breaking through the high redshift bottleneck of Observational Hubble parameter Data: The Sandage-Loeb signal Scheme

    CERN Document Server

    Yuan, Shuo; Zhang, Tong-Jie

    2013-01-01

    We propose a valid scheme to measure the Hubble parameter $H(z)$ at high redshifts by detecting the Sandage-Loeb signal (SL signal) which can be realized by the next generation extremely large telescope. It will largely extend the current observational Hubble parameter data (OHD) towards the redshift region of $z \\in [2.0,5.0]$, the so-called "redshift desert", where other dark energy probes are hard to provide useful information of the cosmic expansion. Quantifying the ability of this future measurement by simulating observational data for a CODEX (COsmic Dynamics and EXo-earth experiment)-like survey and constraining various cosmological models, we find that the SL signal scheme brings the redshift upper-limit of OHD from $z_\\mathrm{max}=2.3$ to $z_\\mathrm{max}\\simeq 5.0$, provides more accurate constraints on different dark energy models, and greatly changes the degeneracy direction of the parameters. For the $\\Lambda$CDM case, the accuracy of $\\Omega_m$ is improved by $58\\%$ and the degeneracy between $\\O...

  5. Marine neurotoxins: State of the art, bottlenecks, and perspectives for mode of action based methods of detection in seafood

    NARCIS (Netherlands)

    Nicolas, J.; Hendriksen, P.J.M.; Gerssen, A.; Bovee, T.F.H.; Rietjens, I.M.C.M.

    2014-01-01

    Marine biotoxins can accumulate in fish and shellfish, representing a possible threat for consumers. Many marine biotoxins affect neuronal function essentially through their interaction with ion channels or receptors, leading to different symptoms including paralysis and even death. The detection of

  6. Bottlenecks in domestic animal populations can facilitate the emergence of Trypanosoma cruzi, the aetiological agent of Chagas disease.

    Science.gov (United States)

    Levy, Michael Z; Tustin, Aaron; Castillo-Neyra, Ricardo; Mabud, Tarub S; Levy, Katelyn; Barbu, Corentin M; Quispe-Machaca, Victor R; Ancca-Juarez, Jenny; Borrini-Mayori, Katty; Naquira-Velarde, Cesar; Ostfeld, Richard S

    2015-07-07

    Faeces-mediated transmission of Trypanosoma cruzi (the aetiological agent of Chagas disease) by triatomine insects is extremely inefficient. Still, the parasite emerges frequently, and has infected millions of people and domestic animals. We synthesize here the results of field and laboratory studies of T. cruzi transmission conducted in and around Arequipa, Peru. We document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more than 85%). By inoculating guinea pigs, an important reservoir of T. cruzi in Peru, and feeding triatomine bugs on them weekly, we demonstrate that, while most animals quickly control parasitaemia, a subset of animals remains highly infectious to vectors for many months. However, we argue that the presence of these persistently infectious hosts is insufficient to explain the observed prevalence of T. cruzi in vector colonies. We posit that seasonal rains, leading to a fluctuation in the price of guinea pig food (alfalfa), leading to annual guinea pig roasts, leading to a concentration of vectors on a small subpopulation of animals maintained for reproduction, can propel T. cruzi through vector colonies and create a considerable force of infection for a pathogen whose transmission might otherwise fizzle out.

  7. Overcoming bottlenecks of enzymatic biofuel cell cathodes: crude fungal culture supernatant can help to extend lifetime and reduce cost.

    Science.gov (United States)

    Sané, Sabine; Jolivalt, Claude; Mittler, Gerhard; Nielsen, Peter J; Rubenwolf, Stefanie; Zengerle, Roland; Kerzenmacher, Sven

    2013-07-01

    Enzymatic biofuel cells (BFCs) show great potential for the direct conversion of biochemically stored energy from renewable biomass resources into electricity. However, enzyme purification is time-consuming and expensive. Furthermore, the long-term use of enzymatic BFCs is hindered by enzyme degradation, which limits their lifetime to only a few weeks. We show, for the first time, that crude culture supernatant from enzyme-secreting microorganisms (Trametes versicolor) can be used without further treatment to supply the enzyme laccase to the cathode of a mediatorless BFC. Polarization curves show that there is no significant difference in the cathode performance when using crude supernatant that contains laccase compared to purified laccase in culture medium or buffer solution. Furthermore, we demonstrate that the oxygen reduction activity of this enzymatic cathode can be sustained over a period of at least 120 days by periodic resupply of crude culture supernatant. This is more than five times longer than control cathodes without the resupply of culture supernatant. During the operation period of 120 days, no progressive loss of potential is observed, which suggests that significantly longer lifetimes than shown in this work may be possible. Our results demonstrate the possibility to establish simple, cost efficient, and mediatorless enzymatic BFC cathodes that do not require expensive enzyme purification procedures. Furthermore, they show the feasibility of an enzymatic BFC with an extended lifetime, in which self-replicating microorganisms provide the electrode with catalytically active enzymes in a continuous or periodic manner.

  8. Incorporation of public hospitals: a "silver bullet" against overcapacity, managerial bottlenecks and resource constraints? Case studies from Austria and Estonia.

    Science.gov (United States)

    Fidler, Armin H; Haslinger, Reinhard R; Hofmarcher, Maria M; Jesse, Maris; Palu, Toomas

    2007-05-01

    This paper presents a new approach for incorporating public hospitals by contrasting the experience from an "old" EU country (Austria) with a new EU member state (Estonia). In the EU (including the new member states) hospital overcapacity is a serious problem, from a technical, fiscal and political perspective. Few countries have succeeded in establishing an appropriate framework for resource management and for guaranteeing long-term financial viability of their hospital network. Many countries are in search of effective policies for improved hospital management and more cost-effective resource use in the health sector. Over the past decade, experiences in Austria and Estonia have emerged as innovative examples which may provide lessons for other EU countries and beyond. This paper describes the evolution of public hospitals from public budgetary units and public management to incorporated autonomous organizations under private corporate law, resulting in a contractual relationship between (public) owners and private hospital management. Outdated and inefficient public sector structures were replaced by more agile corporate management. The arrangement allows for investments, operating costs and budgeting according to strategic business goals as opposed to political "fiat". Shielding hospitals from local political influence is an important aspect of this concept. Horizontal integration through networking of public hospitals and introducing private management helps create a new corporate culture, allowing for more flexibility to achieve efficiencies through downsizing and economies of scale. Based on contracts the new balance between ownership and managerial functions create strong incentives for a more business-like, results-oriented and consumer-friendly management. This was achieved both in Austria and Estonia in a politically sensitive way, adopting a long-term vision and by protecting the interests of hospital owners and staff.

  9. Digestive bottleneck affects foraging decisions in red knots Calidris canutus. II. Patch choice and length of working day

    NARCIS (Netherlands)

    Van Gils, JA; Dekinga, A; Spaans, B; Vahl, WK; Piersma, T

    2005-01-01

    1. When prey occur at high densities, energy assimilation rates are generally constrained by rates of digestion rather than by rates of collection (i.e. search and handle). As predators usually select patches containing high prey densities, rates of digestion will play an important role in the forag

  10. Diversity and stability of Aleutian mink disease virus during bottleneck transitions resulting from eradication in domestic mink in Denmark

    DEFF Research Database (Denmark)

    Christensen, Laurids Siig; Hansen, Lene Gram; Chriél, Mariann;

    2011-01-01

    Aleutian mink disease (plasmacytosis) virus (AMDV) in domestic mink (Neovison vison) has been subject to eradication in Denmark since 1976. In 2001, approximately 5% of Danish mink farms were still infected and all were located in the northern part of the peninsula of Jutland. In the present study...

  11. Fungal host specificity is not a bottleneck for the germination of Pyroleae species (Ericaceae) in a Bavarian forest.

    Science.gov (United States)

    Hynson, Nicole A; Weiß, Michael; Preiss, Katja; Gebauer, Gerhard; Treseder, Kathleen K

    2013-03-01

    Plants that produce dust seeds can recruit fungi to meet their earliest requirements for carbon and other nutrients. This germination strategy, termed initial mycoheterotrophy, has been well investigated among the orchid family, but there are numerous other plant lineages that have independently evolved mycoheterotrophic germination strategies. One of these lineages is the tribe Pyroleae (Ericaceae). While the fungi associated with mature plants in Pyroleae have been fairly well documented, their mycobionts at the germination and seedling stages are largely unknown. Here, we use an in situ seed baiting experiment along with molecular fingerprinting techniques and phylogenetic tests to identify the fungi associated with seedlings of two Pyroleae species, Pyrola chlorantha and Orthilia secunda. Our results indicate that similar to adult plants, Pyroleae seedlings can associate with a suite of ectomycorrhizal fungi. Some seedlings harboured single mycobionts, while others may have been inhabited by multiple fungi. The dominant seedling mycobiont of both Pyroleae species was a fungus of unknown trophic status in the order Sebacinales. This taxon was also the only one shared among seedlings of both investigated Pyroleae species. We discuss these results juxtaposed to orchids and one additional Pyrola species in the context of ontogenetic shifts in fungal host specificity for mycoheterotrophic nutrition.

  12. Armchair-edged nanoribbon as a bottleneck to electronic total transmission through a topologically nontrivial graphene nanojunction.

    Science.gov (United States)

    Jiang, Liwei; Liu, Zhe; Zhao, Xudong; Zheng, Yisong

    2016-03-01

    It is currently a promising approach to experimentally realize the topological insulator phase transition of graphene by introducing the extrinsic spin-orbit coupling (SOC). Then, electronic total transmission through various topological nontrivial graphene nanojunctions (GNJs) is obtainable, if the electronic transport is supported by the helical edge states. Though the bulk graphene is a gapless semiconductor, the inter-valley scattering could introduce a topological trivial gap in semiconducting armchair-edged graphene nanoribbon (GNR). The SOC should be strong enough to reopen a topological nontrivial gap before close such a trivial gap. Therefore, our theoretical study indicates that a semiconducting armchair-edged graphene nanoribbon (GNR) can not develop the helical edge states when the SOC strength is lower than a threshold, though the bulk phase is topological nontrivial. This implies a competition between the SOC and the inter-valley scattering. However, for a metallic armchair-edged GNR, a small SOC can always open a nontrivial gap. Nevertheless, the helical edge state is much less localized than that in a zigzag-edged GNR of the same width. As a result, and by numerically calculating the electronic transmission spectrum of step- and L-shaped GNJs, we conclude that when an armchair-edged GNR is a part of a GNJ, it is the weak point to realize the electronic total transmission even though the bulk phase of graphene is topologically insulating.

  13. A dynamic flux balance model and bottleneck identification of glucose, xylose, xylulose co-fermentation in Saccharomyces cerevisiae

    Science.gov (United States)

    Economically viable production of lignocellulosic ethanol requires efficient conversion of feedstock sugars to ethanol. Saccharomyces cerevisiae cannot ferment xylose, the main five-carbon sugars in biomass, but can ferment xylulose, an enzymatically derived isomer. Xylulose fermentation is slow rel...

  14. Bottlenecks in domestic animal populations can facilitate the emergence of Trypanosoma cruzi, the aetiological agent of Chagas disease

    Science.gov (United States)

    Levy, Michael Z.; Tustin, Aaron; Castillo-Neyra, Ricardo; Mabud, Tarub S.; Levy, Katelyn; Barbu, Corentin M.; Quispe-Machaca, Victor R.; Ancca-Juarez, Jenny; Borrini-Mayori, Katty; Naquira-Velarde, Cesar; Ostfeld, Richard S.

    2015-01-01

    Faeces-mediated transmission of Trypanosoma cruzi (the aetiological agent of Chagas disease) by triatomine insects is extremely inefficient. Still, the parasite emerges frequently, and has infected millions of people and domestic animals. We synthesize here the results of field and laboratory studies of T. cruzi transmission conducted in and around Arequipa, Peru. We document the repeated occurrence of large colonies of triatomine bugs (more than 1000) with very high infection prevalence (more than 85%). By inoculating guinea pigs, an important reservoir of T. cruzi in Peru, and feeding triatomine bugs on them weekly, we demonstrate that, while most animals quickly control parasitaemia, a subset of animals remains highly infectious to vectors for many months. However, we argue that the presence of these persistently infectious hosts is insufficient to explain the observed prevalence of T. cruzi in vector colonies. We posit that seasonal rains, leading to a fluctuation in the price of guinea pig food (alfalfa), leading to annual guinea pig roasts, leading to a concentration of vectors on a small subpopulation of animals maintained for reproduction, can propel T. cruzi through vector colonies and create a considerable force of infection for a pathogen whose transmission might otherwise fizzle out. PMID:26085582

  15. Why do organizations not learn from incidents? Bottlenecks, causes and conditions for a failure to effectively learn

    DEFF Research Database (Denmark)

    Drupsteen, Linda; Hasle, Peter

    2014-01-01

    If organizations would be able to learn more effectively from incidents that occurred in the past, futureincidents and consequential injury or damage can be prevented. To improve learning from incidents,this study aimed to identify limiting factors, i.e. the causes of the failure to effectively...... by the participants in thisstudy, were tightly related to the learning process, but some indirect causes – or conditions – such aslack of ownership and limitations in expertise were also mentioned.The results illustrate that there are two types of causes for the failure to effectively learn: direct causesand indirect...

  16. A microwave detection way by electromagnetic and elastic resonance: Breaking the bottleneck of spatial resolution in microwave imaging

    Science.gov (United States)

    Ji, Zhong; Lou, Cunguang; Shi, Yujiao; Ding, Wenzheng; Yang, Sihua; Xing, Da

    2015-10-01

    The spatial resolution of microwave imaging depends on the geometrical size of the detector. The existing techniques mainly focus on optimizing the antenna design to achieve high detection sensitivity. However, since the optimal antenna size is closely related to the wavelength to be measured, and the miniaturization of the geometrical size is challenging, this limits the spatial resolution of microwave imaging. In this letter, a microwave detection technique based on the electromagnetic-elastic resonance effect is proposed. The piezoelectric materials can produce mechanical responses under microwave excitation, and the amplitude of the microwave can be detected by measuring these responses. In contrast to conventional microwave detection method, the proposed method has distinct advantages in terms of high sensitivity and wide spectral response. Most importantly, it overcomes the limitation of detector size, thus, significantly improving the detection resolution. Therefore, the proposed method has potential for microwave imaging in biomedical applications.

  17. Long orbital period pre-polars containing an early K-type donor stars. Bottleneck accretion mechanism in action

    CERN Document Server

    Tovmassian, G; Zharikov, S; Reichart, D E; Haislip, J B; Ivarsen, K M; LaCluyze, A P; Moore, J P; Miroshnichenko, A S

    2016-01-01

    We studied two objects identified as a Cataclysmic Variables (CVs) with periods exceeding the natural boundary for Roche lobe filling ZAMS secondary stars. We present observational results for V1082 Sgr with 20.82 h orbital period, an object that shows low luminosity state, when its flux is totally dominated by a chromospherically active K- star with no signs of ongoing accretion. Frequent accretion shut-offs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 h binary system. They both have early K-type stars as a donor star. We argue, that similar to the shorter period pre-polars containing M-dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar ...

  18. Overcoming the bottleneck of platelet lysate supply in large-scale clinical expansion of adipose-derived stem cells

    DEFF Research Database (Denmark)

    Glovinski, Peter V; Herly, Mikkel; Mathiasen, Anders B

    2017-01-01

    BACKGROUND: Platelet lysates (PL) represent a promising replacement for xenogenic growth supplement for adipose-derived stem cell (ASC) expansions. However, fresh platelets from human blood donors are not clinically feasible for large-scale cell expansion based on their limited supply. Therefore...... may be an efficient and reliable source of human growth supplement allowing for large-scale ASC expansion for clinical use....... stored in the platelet additive solution, InterSol. Three types of PLs were prepared from outdated PCs with platelets suspended in either (1) InterSol (not manipulated), (2) InterSol + supplemented with plasma or (3) plasma alone (InterSol removed). Using these PLs, we compared ASC population doubling...

  19. The phenotype enhancement method identifies the Xcp outer membrane secretion machinery from Pseudomonas alcaligenes as a bottleneck for lipase production

    NARCIS (Netherlands)

    Gerritse, G; Ure, R; Bizoullier, F; Quax, WJ

    1998-01-01

    Pseudomonas alcaligenes M-1 has been selected from an intensive screening for micro-organisms that can naturally produce a lipase active in detergent formulations. The lipase expression has been increased to allow high level secretion from Pseudomonas alcaligenes, via the introduction of multi-copy

  20. Insertional mutagenesis and deep profiling reveals gene hierarchies and a Myc/p53-dependent bottleneck in lymphomagenesis.

    Directory of Open Access Journals (Sweden)

    Camille A Huser

    2014-02-01

    Full Text Available Retroviral insertional mutagenesis (RIM is a powerful tool for cancer genomics that was combined in this study with deep sequencing (RIM/DS to facilitate a comprehensive analysis of lymphoma progression. Transgenic mice expressing two potent collaborating oncogenes in the germ line (CD2-MYC, -Runx2 develop rapid onset tumours that can be accelerated and rendered polyclonal by neonatal Moloney murine leukaemia virus (MoMLV infection. RIM/DS analysis of 28 polyclonal lymphomas identified 771 common insertion sites (CISs defining a 'progression network' that encompassed a remarkably large fraction of known MoMLV target genes, with further strong indications of oncogenic selection above the background of MoMLV integration preference. Progression driven by RIM was characterised as a Darwinian process of clonal competition engaging proliferation control networks downstream of cytokine and T-cell receptor signalling. Enhancer mode activation accounted for the most efficiently selected CIS target genes, including Ccr7 as the most prominent of a set of chemokine receptors driving paracrine growth stimulation and lymphoma dissemination. Another large target gene subset including candidate tumour suppressors was disrupted by intragenic insertions. A second RIM/DS screen comparing lymphomas of wild-type and parental transgenics showed that CD2-MYC tumours are virtually dependent on activation of Runx family genes in strong preference to other potent Myc collaborating genes (Gfi1, Notch1. Ikzf1 was identified as a novel collaborating gene for Runx2 and illustrated the interface between integration preference and oncogenic selection. Lymphoma target genes for MoMLV can be classified into (a a small set of master regulators that confer self-renewal; overcoming p53 and other failsafe pathways and (b a large group of progression genes that control autonomous proliferation in transformed cells. These findings provide insights into retroviral biology, human cancer genetics and the safety of vector-mediated gene therapy.

  1. Ad-Hoc网络中的瓶颈节点性能分析%Performance Analysis of Bottleneck Nodes in Ad-Hoc Network

    Institute of Scientific and Technical Information of China (English)

    霍俊伟; 明廷堂; 吴绍兴

    2009-01-01

    由于在MAC子层上采用公平的无线电资源共享,Ad-Hoc网络趋向于在所有的活动节点之间平等地共享信道容量,而对负载考虑较少.这种共享策略的一个潜在缺陷是,为多个流充当中继的节点可能会成为Ad-hoc网络的性能瓶颈.为了从流的层面对这种节点的网络行为进行分析,首先描述了一个以IEEE 802.11为底层技术的Ad-Hoc网络的简单场景.然后在此基础上对该场景进行数学建模,并对其中的节点进行性能分析,最后给出模拟结果.

  2. A recent bottleneck in the warthog and elephant populations of Queen Elizabeth National Park, revealed by a comparative study of four mammalian species in Uganda national parks

    DEFF Research Database (Denmark)

    Muwanika, Vincent B.; Siegismund, Hans Redlef; Okello, John Bosco A.

    2003-01-01

    Until 1972, Uganda's national parks boasted of large numbers of large mammal species. Following the breakdown of law and order between 1972 and 1985, large-scale poaching led to an unprecedented decline in numbers of most large mammals in Uganda's national parks. However, the extent of decline...... microsatellite loci (for elephant and warthog populations) and mitochondrial control sequence variation in the warthogs, elephants, buffaloes and hippopotamuses. Queen Elizabeth National Park showed extreme reduction in nucleotide diversity for two species, the common warthog (p= 0.0%) and African elephant (p= 0...... varied in the different parks across different animal species. We have investigated the genetic effects of these reductions in four mammalian species (the common warthog, African savannah elephant, savannah buffalo and common river hippopotamus) from the three major parks of Uganda using both...

  3. Early diagnosis of neurodegenerative diseases - the long awaited Holy Grail and bottleneck of modern brain research - 19th HUPO BPP workshop: May 22-24, 2013, Dortmund, Germany.

    Science.gov (United States)

    Schrötter, Andreas; Magraoui, Fouzi El; Gröttrup, Bernd; Wiltfang, Jens; Heinsen, Helmut; Marcus, Katrin; Meyer, Helmut E; Grinberg, Lea T; Park, Young Mok

    2013-10-01

    The HUPO Brain Proteome Project (HUPO BPP) held its 19th workshop in Dortmund, Germany, from May 22 to 24, 2013. The focus of the spring workshop was on strategies and developments concerning early diagnosis of neurodegenerative diseases.

  4. Legal concepts to eliminate the bottleneck in energy-saving modernisations for existing buildings; Rechtskonzepte zur Beseitigung des Staus energetischer Sanierungen im Gebaeudebestand

    Energy Technology Data Exchange (ETDEWEB)

    Klinski, Stefan [Hochschule fuer Wirtschaft und Recht (HWR), Berlin (Germany)

    2009-10-15

    The research project looked at the following: 1. Whether and to what extent the German tenancy law creates, on the one hand, adequate incentives for energy-saving modernisations of existing buildings, on the one hand, and, on the other, whether it creates legal obstacles. 2. How these obstacles could be eliminated i.e. by changing existing tenancy law and instead creating stimuli for energy-saving modernization of existing rental buildings. The report contents a number of specific recommendations for an energy-related reform of the German tenancy law. Major recommendations are: - to eliminate the current toleration duty for modernisation measures if changes are made to the building that conflict with the duties arising from the energy saving provisions of public law, - to consider energy-saving characteristics in the reference rent customary in the locality, - to create a possibility for imposing a flat-rate surcharge which is linked to the savings in heating costs for energy-saving improvement. (orig.)

  5. Mental rotation impairs attention shifting and short-term memory encoding: neurophysiological evidence against the response-selection bottleneck model of dual-task performance.

    Science.gov (United States)

    Pannebakker, Merel M; Jolicœur, Pierre; van Dam, Wessel O; Band, Guido P H; Ridderinkhof, K Richard; Hommel, Bernhard

    2011-09-01

    Dual tasks and their associated delays have often been used to examine the boundaries of processing in the brain. We used the dual-task procedure and recorded event-related potentials (ERPs) to investigate how mental rotation of a first stimulus (S1) influences the shifting of visual-spatial attention to a second stimulus (S2). Visual-spatial attention was monitored by using the N2pc component of the ERP. In addition, we examined the sustained posterior contralateral negativity (SPCN) believed to index the retention of information in visual short-term memory. We found modulations of both the N2pc and the SPCN, suggesting that engaging mechanisms of mental rotation impairs the deployment of visual-spatial attention and delays the passage of a representation of S2 into visual short-term memory. Both results suggest interactions between mental rotation and visual-spatial attention in capacity-limited processing mechanisms indicating that response selection is not pivotal in dual-task delays and all three processes are likely to share a common resource like executive control.

  6. Experts' view:how to break the bottleneck of IC designers' training%专家论道:突破IC设计人才培养瓶颈

    Institute of Scientific and Technical Information of China (English)

    吴瑞生

    2004-01-01

    人才一直被认为是中国IC设计产业发展的瓶颈,IC设计培训师资人才又被认为是瓶颈中的瓶颈。最近,国家IC人才培养基地国际名师课程授课示范讲座最近在杭州结业期间,就我国IC设计业发展、IC设计人才培养和IC设计师资培训等问题,本刊记者采访了有关专家。

  7. 社交网站盈利模式与发展探讨%Revenue Model and Development Bottleneck of Social Network Sites

    Institute of Scientific and Technical Information of China (English)

    李广春

    2013-01-01

    Along with the expansion of the user scale in social network site, the business value of social network site be-comes increasingly salient, as a result, how to exploit and use it is of significant important. Although there are some revenue mod-els for social network sites at present, such as advertising, web games, virtual goods sales, the profitability and development di-rection of social network site is not clear. Even worse, the homogeneity of social network site has become seriously as the low threshold of entrance, some loyal users will simply fade away. If the social network site operators have high ambitions to sustain-able development, they must learn how to maintain a good customer relationship and do better customer service network, after-wards they can promote the rational exploitation of user resources, and make the joint of capital market to realize benign circle for development.%  随着社交网站用户规模的扩大,社交网站的商业价值也日渐凸显,对其价值的开发和利用则显得尤为重要。虽然涌现出了如广告、网页游戏、虚拟物品销售等盈利模式的业务,但由于网站对未来的发展不够明朗,盈利效果也并不理想,无法支撑网站的持续发展,同时社交网站领域新加入者增多,网站同质化现象相当严重,网站功能开发无法满足用户不断变化的娱乐需求,用户逐渐消失。社交性质的网站想要获得可持续的长远发展,就必须在维系用户关系、做好网络服务的基础上,将用户关系转化为网站可以开发利用的资源,积极探索稳定可行的盈利模式,并与资本市场进行对接,最终实现良性循环的商业发展。

  8. Population genetic analysis of microsatellite variation of guppies (Poecilia reticulata) in Trinidad and Tobago: evidence for a dynamic source-sink metapopulation structure, founder events and population bottlenecks.

    Science.gov (United States)

    Barson, N J; Cable, J; Van Oosterhout, C

    2009-03-01

    Riverine fish populations are traditionally considered to be highly structured and subject to strong genetic drift. Here, we use microsatellites to analyse the population structure of the guppy (Poecilia reticulata), focussing on the headwater floodplain area of the Caroni drainage in Trinidad. We also analyse the population genetics of guppies in the Northern Drainage in Trinidad, a habitat characterized by rivers flowing directly into the sea, and a small isolated population in Tobago. Upland Caroni populations are highly differentiated and display low levels of genetic diversity. However, we found no evidence to suggest that these upland populations experienced recent population crashes and the populations appear to approach mutation-drift equilibrium. Dominant downstream migration over both short- and long-time frames has a strong impact on the population genetics of lowland Caroni populations. This drainage system could be considered a source-sink metapopulation, with the tributary furthest downstream representing a 'super sink', receiving immigrants from rivers upstream in the drainage. Moreover, the effective population size in the lowlands is surprisingly low in comparison with the apparently large census population sizes.

  9. 商业银行绿色信贷的瓶颈与应对策略%Bottleneck and Countermeasures of Commercial Bank’s Green Credit

    Institute of Scientific and Technical Information of China (English)

    睢博; 胡杰

    2013-01-01

      自2007年7月我国实施绿色信贷政策以来,商业银行对节能减排项目的支持力度日益增强。但是,商业银行对高耗能企业的贷款却有增无减。文章从风险预期的角度,运用数理分析方法,对商业银行增加高耗能产业贷款的原因进行了探讨,认为商业银行给予高耗能企业贷款源于企业财富门槛和风险门槛,而影响企业财富门槛和风险门槛的主要因素是商业银行对于投资项目成功概率的判定;在长期动态过程中,商业银行对项目成功概率的判定,是基于企业前一期的投资经历。%  Since the policy of the green credit was carried in July of 2007 ,the commercial banks always sup-port the project of energy conservation measures increasingly day by day .However ,the size of the loan for highly energy-consuming companies has been raised continuously .This paper is discussing the cause of the increasing loan for highly energy-consuming companies by the method of mathematical analysis from the perspective of risk expectation .The main reason for this phenomenon is the limitation of wealth threshold and risk threshold ,which are the principal factors to the judgment on the investment projects success ratio of commercial bank .In the long and dynamic process ,the success ratio determined by commercial bank is based on the investment experience in the previous period .

  10. Removing the taint : bottlenecks and possible directions for a solution in the marketing of the meat of non-castrated male pigs

    NARCIS (Netherlands)

    Klep, L.M.F.

    2008-01-01

    Onderzoeksresultaten laten zien dat het onwaarschijnlijk is dat er een eenvoudige oplossing bestaat voor het stoppen met castratie van beertjes in de varkenshouderij. Er dient gezocht te worden naar een combinatie van verschillende methoden. De berengeurproblematiek is primair een probleem van markt

  11. 高校建设媒介融合实验室的契机与瓶甄%Opportunity and Bottleneck in Building University Media Convergence Labs

    Institute of Scientific and Technical Information of China (English)

    陈恺思

    2012-01-01

    媒介融合的发展使我国高校新闻教育面临巨大挑战,培养“复合型”新闻人才已成为我国高校新闻教育的首要目标,而媒介融合实验室作为保证媒介融合人才培养质量的关键,其建设虽有一定机遇,却也面临着资金缺乏、师资紧缺、旧实验室改造困难等不少困境。在机遇中寻找突破,需要考虑与具备开发媒介融合系统的公司或研究机构建立开发合作关系,同时积极推行师资方面的“走出去请进来”的方法才能最终获取成功。%With the development of media convergence in our country, university news education is being faced with enormous challenge. Thus, "Versatile" news talents are becoming more important in university news education, and media convergence labs are the key to ensure the quality of personnel training. In labs' construction, not only opportunity, but also difficulties such as lack of funding, shortage of qualified teacher, and old laboratory renovation, etc. are faced with. In order to find a breakthrough, cooperation with competent companies or research institutions in developing media convergence systems is needed. At last, active promotion of teaching personnel' s "go-out-and-come-in" system will also help final suecess.

  12. Previous estimates of mitochondrial DNA mutation level variance did not account for sampling error: comparing the mtDNA genetic bottleneck in mice and humans.

    Science.gov (United States)

    Wonnapinij, Passorn; Chinnery, Patrick F; Samuels, David C

    2010-04-09

    In cases of inherited pathogenic mitochondrial DNA (mtDNA) mutations, a mother and her offspring generally have large and seemingly random differences in the amount of mutated mtDNA that they carry. Comparisons of measured mtDNA mutation level variance values have become an important issue in determining the mechanisms that cause these large random shifts in mutation level. These variance measurements have been made with samples of quite modest size, which should be a source of concern because higher-order statistics, such as variance, are poorly estimated from small sample sizes. We have developed an analysis of the standard error of variance from a sample of size n, and we have defined error bars for variance measurements based on this standard error. We calculate variance error bars for several published sets of measurements of mtDNA mutation level variance and show how the addition of the error bars alters the interpretation of these experimental results. We compare variance measurements from human clinical data and from mouse models and show that the mutation level variance is clearly higher in the human data than it is in the mouse models at both the primary oocyte and offspring stages of inheritance. We discuss how the standard error of variance can be used in the design of experiments measuring mtDNA mutation level variance. Our results show that variance measurements based on fewer than 20 measurements are generally unreliable and ideally more than 50 measurements are required to reliably compare variances with less than a 2-fold difference.

  13. The Bottleneck and Solution of Chinese Folk Sports Culture Development%我国民俗体育文化发展瓶颈与解决策略

    Institute of Scientific and Technical Information of China (English)

    何丽琴

    2014-01-01

    Sports is one of the traditional project activities in China for thousands of years , its historical position and function are very important .The folk sports culture in sports , its development status is not optimistic .A lot of people without a conscious of protecting and inheriting the attitude to the sports culture , together with the relevant laws and regulations on state is not perfect , caused by a considerable impact on the development of these cultural . Many business Companies take folk sports culture to increase their business economic benefits of gimmicks , only pay attention to the value of economy , ignoring its cultural value and cultural value .To solve these problems , we must formulate relevant policies to protect the folk sports culture .%体育运动是我国几千年来的传统活动项目之一,其历史地位和作用都非常重要。而对于体育中的民俗体育文化来讲,其发展现状不容乐观。很多民众对于这种体育文化没有一种自觉的保护和传承的态度,再加上国家的相关法律法规也不完善,导致了这些文化的发展受到了相当大的影响。很多的商业公司将民俗的体育文化作为增加自己商业经济效益的噱头,只注重挖掘其经济方面的价值,忽视了其文化方面的价值以及人文方面的价值。针对这些问题,我们必须制定相关的政策来保护民俗体育文化。

  14. Career Development Bottleneck of the Female Teachers in University%高校女教师职业发展的瓶颈

    Institute of Scientific and Technical Information of China (English)

    穆岚; 李宝华

    2012-01-01

    高校女教师是高校教师队伍的重要组成部分,受自身成就动机、多重角色冲突及“玻璃天花板”效应等的影响,其职业发展面临瓶颈。对影响高校女教师职业发展的因素进行深入分析,提出相应对策,是高校女教师自身发展的需要,也是使高校教师队伍更加科学、和谐发展的需要。%The female teachers in university is an important part of the university teachers. Because of the own achievement motivation, multi-role conflict and the " glass ceiling" effect, the female teachers facing the bottle- necks in their career development. Depth analysis of the effect factors and proposed countermeasures is the needs for both the female teachers in their own development and university teachers in more scientific and harmonious development.

  15. Face to face:Qiu He,Party secretary of Kunming,Yunnan province on breaking the bottleneck of mindset%对话仇和

    Institute of Scientific and Technical Information of China (English)

    王运宝

    2010-01-01

    @@ 从宿迁到昆明,仇和一路走来,而新闻媒体中的仇和、市民话语中的仇和与真实的仇和等不同影像,在这个过程中相互交织与叠加.自从就任云南省委常委、昆明市委书记,仇和用一种"旋风式"的执政方式搅动起这座"软绵绵"的西南城市.

  16. Extracellular Electron Transfer Is a Bottleneck in the Microbiologically Influenced Corrosion of C1018 Carbon Steel by the Biofilm of Sulfate-Reducing Bacterium Desulfovibrio vulgaris.

    Directory of Open Access Journals (Sweden)

    Huabing Li

    Full Text Available Carbon steels are widely used in the oil and gas industry from downhole tubing to transport trunk lines. Microbes form biofilms, some of which cause the so-called microbiologically influenced corrosion (MIC of carbon steels. MIC by sulfate reducing bacteria (SRB is often a leading cause in MIC failures. Electrogenic SRB sessile cells harvest extracellular electrons from elemental iron oxidation for energy production in their metabolism. A previous study suggested that electron mediators riboflavin and flavin adenine dinucleotide (FAD both accelerated the MIC of 304 stainless steel by the Desulfovibrio vulgaris biofilm that is a corrosive SRB biofilm. Compared with stainless steels, carbon steels are usually far more prone to SRB attacks because SRB biofilms form much denser biofilms on carbon steel surfaces with a sessile cell density that is two orders of magnitude higher. In this work, C1018 carbon steel coupons were used in tests of MIC by D. vulgaris with and without an electron mediator. Experimental weight loss and pit depth data conclusively confirmed that both riboflavin and FAD were able to accelerate D. vulgaris attack against the carbon steel considerably. It has important implications in MIC failure analysis and MIC mitigation in the oil and gas industry.

  17. Divided infraorbital foramen in the lion (Panthera leo): its implications for colonisation history, population bottlenecks, and conservation of the Asian lion (P. l. persica)

    NARCIS (Netherlands)

    Yamaguchi, N.; Kitchener, A.C.; Driscoll, C.A.; Macdonald, D.W.

    2009-01-01

    A divided infraorbital foramen is an important morphological feature in lion taxonomy and has previously been considered to occur only in the Asian lion, Panthera leo persica. Based on an examination of 498 lion skulls from museum collections in Europe and southern Africa, we report for the first ti

  18. Yasukuni Shrine--the Bottleneck of Sino-Japanese Relations%靖国神社--中日关系的一个瓶颈

    Institute of Scientific and Technical Information of China (English)

    寇春莹; 魏桦

    2004-01-01

    靖国神社问题已经成为中日关系中的一个非常敏感的政治问题.靖国神社问题的实质,就是日本政府如何认识和对待过去的侵略历史.这既关系到曾经遭受日本军国主义侵略之害的亚洲各国人民的感情的问题,同时也关系到日本这个国家的今后走向.日本政界要员连续参拜靖国神社既有其深刻的历史根源,也与日本九十年代以来的国内政治、经济状况密切相关,同时参拜之举也是政客为迎合国内政治气候的一种政治手腕.进入新世纪,中日两国只有在正视历史的基础上,把历史问题与双方关系的发展联系起来看,坚持"以史为鉴,面向未来"的原则,才能够保证中日关系健康的发展.

  19. Paradigm shift in transport legislation or rather at the 'bottleneck'; Paradigmenwechsel im Befoerderungsrecht oder am 'Flaschenhals'

    Energy Technology Data Exchange (ETDEWEB)

    Naeser, Hanns [GNS Gesellschaft fuer Nuklear-Service mbH, Essen (Germany)

    2015-01-15

    In the year just started significant decisions with considerable consequences by the Federal Constitutional Court and the Federal Administrative Court in the field of nuclear law are expected. Especially the decision with regards to 'nuclear phase-out' within the 13th amendment of the Atomic Energy Act is being eagerly expected, as with its far-reaching consequences also fundamental constitutional questions need to be answered. The Federal Administrative Court will need to decide on the question, whether she admits the appeal against the Brunsbuettel decision by the Higher Administrative Court Schleswig-Holstein (HAC), which from the view of claimant shifted the fundamental basis of demarcation of responsibilities between the executive and judiciary power. In comparison to these fundamental decisions the awaited decision by the HAC on nuclear transport legislation seems of subordinate importance, although she will proceed with a paradigm shift in the legal area. The decision deals with the question as to whether and when a right of action from a third party within the nuclear transport legislation can be accepted or more precisely under which preconditions a third party has clear standing against a nuclear transport authorisation. As the site selection law (issued on 23 July 2013 BGBI I p. 2552) excludes the recirculation of vitrified waste block canisters from reprocessing spent fuel elements to the transport cask storage facility Gorleben, the decision by the HAC Lueneburg for this site will only be relevant for present unpredictable transportations from the transport cask storage facility Gorleben to a final repository. If necessary interest to seek a declaratory judgment for declaratory action, in concreto danger of recurrence will be approved, is another matter.

  20. Corneal replication is an interferon response-independent bottleneck for virulence of herpes simplex virus 1 in the absence of virion host shutoff.

    Science.gov (United States)

    Pasieka, Tracy Jo; Menachery, Vineet D; Rosato, Pamela C; Leib, David A

    2012-07-01

    Herpes simplex viruses lacking the virion host shutoff function (Δvhs) are avirulent and hypersensitive to type I and type II interferon (IFN). In this study, we demonstrate that even in the absence of IFN responses in AG129 (IFN-αβγR(-/-)) mice, Δvhs remains highly attenuated via corneal infection but is fully virulent via intracranial infection. The data demonstrate that the interferon-independent inherent replication defect of Δvhs has a significant impact upon peripheral replication and neuroinvasion.

  1. From "Migrant Workers Boom" to "Migrant Workers Scarcity"——Analysis of Institutional Bottleneck of Rural Surplus Labors Transfer in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Through description of three-steps characteristic of dual economic theory and its practical significance to the process of industrialization and urbanization in China,and making comparative analysis between important criterion of "Lewis turning point" and current situation of rural surplus labors market in China,we can find that there exists a great deal of surplus labors in rural areas in our country,improvement of peasant income is the result of external interference of government,and demographic dividend in our country hasn’t finished.These phenomena go against the theory of "Lewis turning point".So it can prove that "Lewis turning point" in China hasn’t come yet.The paper points out the major factors of coexistence of "migrant workers scarcity" and labors redundancy in our country.The first one is structure contradiction of labors market;the second one is law of supply-demand of labors market;the third one is institutional barrier which hinders labors in free flow of census register and social guarantee.Therefore,if we want to realize successful transfer of rural surplus labors and the goal of industrialization and urbanization,we must promote upgrading of industrial structure,change the style of economic growth and realize harmonious development of regional economy in macrocosmic level;And in microcosmic level,we should eliminate institutional barrier which hinders transfer of rural surplus labors.

  2. 大学生参与课余体育的瓶颈问题%"Bottleneck" Research on College Students' Participating in Extracurricular Sports

    Institute of Scientific and Technical Information of China (English)

    凌青东

    2012-01-01

    Extracurricular sports are the key ensurance of improving the physical fitness of college students.Based on the subjective cognition and participating degree of college students and starting from the social factors,family factors and school factors which influence students' physique,this paper will study on the reasons of the decline of college students' physical fitness in order to solve the problems.%课余体育是大学生身体素质提高的关键保障.本研究从大学生对课余体育的主观认识和参与程度,以及影响学生体质的社会因素、家庭因素、学校因素等维度出发,探讨大学生身体素质下降的原因,以便"对症下药".

  3. Globalization as a Driver or Bottleneck for Sustainable Development: Some Empirical, Cross-National Reflections on Basic Issues of International Health Policy and Management

    Directory of Open Access Journals (Sweden)

    Arno Tausch

    2013-01-01

    Full Text Available BackgroundThis article looks at the long-term, structural determinants of environmental and public health performance in the world system. MethodsIn multiple standard ordinary least squares (OLS regression models, we tested the effects of 26 standard predictor variables, including the ‘four freedoms’ of goods, capital, labour and services, on the following indicators of sustainable development and public health: avoiding net trade of ecological footprint global hectare (gha per person; avoiding high carbon emissions per million US dollars GDP; avoiding high CO2 per capita (gha/cap; avoiding high ecological footprint per capita; avoiding becoming victim of natural disasters; a good performance on the Environmental Performance Index (EPI; a good performance on the Happy Life Years (HLYs scale; and a good performance on the Happy Planet Index (HPI. ResultsOur research showed that the apprehensions of quantitative research, critical of neo-liberal globalization, are fully vindicated by the significant negative environmental and public health effects of the foreign savings rate. High foreign savings are indeed a driver of global footprint, and are a blockade against a satisfactory HPI performance. The new international division of labour is one of the prime drivers of high CO2 per capita emissions. Multinational Corporation (MNC penetration, the master variable of most quantitative dependency theories, blocks EPI and several other socially important processes. Worker remittances have a significant positive effect on the HPI, and HLYs. ConclusionWe re-analysed the solid macro-political and macro-sociological evidence on a global scale, published in the world’s leading peer-reviewed social science, ecological and public health journals, which seem to indicate that there are contradictions between unfettered globalization and unconstrained world economic openness and sustainable development and public health development. We suggest that there seems to be a strong interaction between ‘transnational capitalist penetration’ and ‘environmental and public health degradation’. Global policy-making finally should dare to take the globalization-critical organizations of ‘civil society’ seriously. This conclusion not only holds for the countries of the developed “West”, but also, increasingly, for the growing democracy and civil society movements around the globe, in countries as diverse as Brazil, Russia, China, or ever larger parts of the Muslim world.

  4. 民营银行发展的瓶颈及对策%A Brief Analysis of Bottlenecks and Development Model during Early Development of the Private Banks

    Institute of Scientific and Technical Information of China (English)

    刘非; 郑一凡

    2015-01-01

    随着我国金融改革步步深入,顶层框架设计日趋完善,民营银行在优化金融生态,构建公平机制上将发挥不可估量的作用。鉴于目前监管政策和实施细则尚不完善,试点的差异化经营经验仍显不足,其初期的发展将面临资产规模、风控体系、资金保障等瓶颈问题,如何在现有政策框架内,正确寻找自身定位,创新思路应对挑战,以取得长久持续发展非常关键。在现有政策回顾、政策意图分析、初期瓶颈探讨和政府、民营银行的应对措施分析的基础上,完善政策保障,创新金融服务,才能推动民营银行持续健康发展。%As China’s financial reform steps further and top-level design is gradually improved, private bank is able to step on the historical stage which plays an immeasurable role in the optimization of financial ecology and fair mechanism. In the face of the faultiness of policy and regulatory and the inexperience in management, the expansion of private bank will be limited in the scale of assets, risk-control system and follow-up fund. This paper, which can be divided into four aspects, will focus on accurately positioning in current market, innovation of business model and the path of sustainable development in order to make recommendations for the development of private banks. Finally, the paper includes that only we improve the policy guarantee, innovate the financial service could promote private bank continuous and healthy development.

  5. Mental rotation impairs attention shifting and short-term memory encoding: neurophysiological evidence against the response-selection bottleneck model of dual-task performance

    NARCIS (Netherlands)

    M.M. Pannebakker; W.O. van Dam; G.P.H. Band; K.R. Ridderinkhof; B. Hommel

    2011-01-01

    Dual tasks and their associated delays have often been used to examine the boundaries of processing in the brain. We used the dual-task procedure and recorded event-related potentials (ERPs) to investigate how mental rotation of a first stimulus (S1) influences the shifting of visual-spatial attenti

  6. Breaking the Land Bottlenecks in the Economy Development%破解园区经济发展中的土地瓶颈

    Institute of Scientific and Technical Information of China (English)

    岳传明

    2014-01-01

    为更好地为园区经济发展提供国土资源服务、保障园区经济发展,本文对国土资源管理工作中遇到的影响园区经济发展的理论困惑和实践难题进行了分析,破解了园区经济发展中的土地瓶颈,提出了相应的建议和对策。%In order to bet er provide land and resources serv-ices of economic development, guarantee the park economic development zone. This article analyzes the influence of land and resources management in the park theoretical confusion and practical problems of economic development, and break-ing zone land bot lenecks in the economy development, puts forward the corresponding suggestions and countermeasures.

  7. 瓶颈网络TCP/主动队列管理模型及仿真%TCP/Active Queue Management Model and Simulation for Bottleneck Networks

    Institute of Scientific and Technical Information of China (English)

    曹振臻; 肖扬; 迟彩霞

    2009-01-01

    提出了一种基于离散时间Markov链的时延闭环反馈TCP/AQM(Active Queue Management)模型,并得到其稳态分布.通过以环路时延为单位,将系统时间分割成长度不同的时隙,分析每个时隙内TCP发送端发送窗口模型和瓶颈路由器队列模型.通过结合相邻时隙的参数,提出了TCP/AQM整体分析模型.该模型可以估计路由器的队列平均长度和丢包率、TCP发送端的平均发送窗口值,因此可以用于分析AQM算法性能以及给新算法的设计提供理论支持.通过在Matlab实施该模型与NS2仿真结果作比较,证实了该模型在模拟时延闭环反馈的TCP/RED系统的有效性.

  8. 一种动态识别瓶颈机床的启发算法%A heuristic algorithm for dynamic identify bottleneck machine

    Institute of Scientific and Technical Information of China (English)

    杨宏安; 孙树栋; 王荪馨

    2006-01-01

    瓶颈机床是影响车间生产和调度的关键因素.针对Job shop调度中的瓶颈机床确定问题,提出了动态识别瓶颈机床的搜索算法框架.并详细讨论了算法框架中的工序开始时间窗、搜索空间的概率模型和动态启发算法.最后用算列验证了动态启发算法的有效性.

  9. Renewable marine energies, state of the art, technological bottlenecks and perspectives; Les energies marines renouvelables, etat de l'art, verrous technologiques et perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, Ph. [Centre IFREMER Dir., 29 - Brest (France)

    2011-05-15

    The ocean is a huge reservoir of energy that is very little worked. This article reviews the different ways to use the energy stored in the ocean: -) thermal energy, -) the energy of the ocean streams, -) the energy of the tides, -) the energy of the waves, and -) the off-coast wind energy. This article reviews the different projects throughout the world, the potentialities of such energies and the technical challenges to overcome. (A.C.)

  10. Research on the Bottleneck Delay of Internet IP-Level Topology%互联网IP级拓扑瓶颈时延的研究分析

    Institute of Scientific and Technical Information of China (English)

    赵海; 姚呈呈; 艾均; 贾思媛

    2014-01-01

    采用CAIDA提供的海量数据样本,主要针对网络中的瓶颈时延行为特征进行分析.首先针对路径中的关键时延进行统计分析,发现超过80%的路径中产生了瓶颈时延,进一步对瓶颈时延量化分析得出,由于瓶颈时延的存在导致网络直径相差不大的路径,其网络时延相差悬殊;接着将网络时延和瓶颈时延两端的IP地址在地理位置上的分布特征进行统计,发现二者的地理分布特征有较大差别;最后研究分析了产生瓶颈时延的原因,得出在远距离范围内,传播时延是导致瓶颈时延最重要的因素,而在近距离范围内,排队时延是导致瓶颈时延最重要的因素.

  11. Patterns of genetic diversity resulting from bottlenecks in European black pine, with implications on local genetic conservation and management practices in Bulgaria

    NARCIS (Netherlands)

    Naydenov, Krassimir D.; Mladenov, Ivica; Alexandrov, Alexander; Naydenov, Michel K.; Gyuleva, Veselka; Goudiaby, Venceslas; Nikolić, Biljana; Kamary, Salim

    2015-01-01

    In the present study, we investigated the genetic structure and diversity of P.nigra populations in Bulgaria, using simple sequence nuclear repeats. Among-population structure was studied with distance and Bayesian frequency methods, assuming geometric distance and a “non-admixture” model. The “N

  12. Congestion Control of ATM Networks with Multiple Bottlenecks%多瓶颈链路ATM网络的拥塞控制

    Institute of Scientific and Technical Information of China (English)

    任涛; 曲蓉霞; 井元伟

    2009-01-01

    基于含有多个瓶颈节点的ATM网络模型,设计了ABR流量显式速率控制器来解决多瓶颈节点网络的拥塞问题.给出了系统稳定的充分条件,并针对变化的ABR用户数量,给出了对可控ABR用户数实时估计的方法.最后通过在不同条件下的数值仿真,验证了所设计的控制算法不但可以克服多个传播时延给控制带来的不利影响,有较强的鲁棒性,而且还可以很好地预测ABR用户数量的变化.

  13. A bottleneck model for the congestion of through rail transit%直达轨道交通的拥挤瓶颈模型

    Institute of Scientific and Technical Information of China (English)

    林震; 杨浩

    2003-01-01

    首先,运用瓶颈模型的思想对直达轨道交通拥挤进行分析.分析包括两个方面,一是考虑轨道交通输送能力的限制,提出了拥挤风险费用的概念,解决了轨道交通出行费用不等的问题;二是根据用户平衡原则,通过寻找出行者选择不同出发时刻的费用平衡点,得到平衡情况下的出行费用;其次,对拥挤风险费用与出发率等特征进行分析,得出平衡条件下的出行规律,并与经典瓶颈模型进行比较.最后,给出一个算例.

  14. 基于Greenshields模型的瓶颈路段拥挤收费问题%Greenshields model based congestion pricing in bottleneck road section

    Institute of Scientific and Technical Information of China (English)

    薛莹; 任华玲

    2013-01-01

    基于Greenshields模型,描述了瓶颈路段上流量的演化过程,并计算每个时刻出行者的出行费用.通过出行费用与流量的关系调整每个时刻流量的分配,直至达到用户平衡状态.文中在拥挤时段设置了一定水平的收费,并分析了收费后路段上的流量分配情况和拥挤状况.在现象分析后得到了较好的收费水平和收费时段,以及收费对缓解交通拥挤的作用.

  15. Analysis of the Bottleneck of SME Financing and Countermeasures%中小企业融资瓶颈及对策分析

    Institute of Scientific and Technical Information of China (English)

    周艳

    2011-01-01

    SME financing is a world-class problem,so our government should reform the credit, at the same time the SMEs should optimize the financing environment for SMEs, improve credit rating, and broaden financing channels to raise more funds for construction.%中小企业融资难是世界级难题,为此我国政府应该力求信贷改革;同时中小企业也要优化融资环境,提高信用等级,拓宽融资渠道募集更多的资金.

  16. B2C E-commerce Development Bottleneck-Third-party Logistics and Distribution%B2C电子商务发展瓶颈—第三方物流配送

    Institute of Scientific and Technical Information of China (English)

    韩甘临

    2011-01-01

    The electronic business enterprise logistics strategy is to improve the main logistics distribution quality, best serviceto keep consumers distribution loyalty to as low as possible operation cost to reach a certain customer satisfaction.Logistics distribution is electronic commerce basic component of electronic commerce development is the most weak links.As the electronic commerce development,the logistics of electronic business rote has become more obvious,e-commerce there is a special relationship.With the rapid development in information technology, and logistics development level and electronic commerce development level but also has the very big disparity.At the end of the logistics problems to solve,marks the end of the electroniccommerce flow. Logistics distribution and e-commerce business process of subsequent guarantee%电子商务企业的物流战略主要是提高物流配送质量,以最好地配送服务来维持消费者忠诚度,以尽可能低的企业运营成本来达到一定客户满意程度。物流配送是电子商务基本组成部分,也是电子商务发展最为薄弱环节。随着电子商务发展,物流对电子商务的作用也日益突出,它与电子商务存在着一种特殊关系。随着信息技术地飞速发展,而物流发展水平却与电子商务发展水平还有很大差距。物流问题的最后解决,标志着整个电子商务流程的结束。物流配送又是电子商务中商务流程的后续保证。

  17. Bus and Coach Market Research Methodology and Analysis of and Solutions to the Bottle-neck Issue%客车市场研究方法及瓶颈问题解析

    Institute of Scientific and Technical Information of China (English)

    杨立慧

    2010-01-01

    @@ 引入战略思维,提升客车市场研究高度 引入战略思维就是通过有效组合企业内部资源,在变化的环境中确定企业发展方向和经营范围,从而获得竞争优势,以满足市场需求和企业拥有人的需求;因此,战略的核心问题就是在解决市场竞争能力基础上,达到企业资源效益最大化.其作用主要体现在2方面.

  18. A Work-in-Process Estimation Method Based on Bottleneck Machines' Process Time Variability%基于瓶颈设备处理时间波动的WIP估计方法

    Institute of Scientific and Technical Information of China (English)

    蒋舒宇; 周炳海

    2008-01-01

    针对半导体晶圃制造系统缩短制造周期(CT)和提高产出率(TH)两个目标,考虑了瓶颈设备偏离其正常和可预测处理时间的情况(即瓶颈设备处理时间波动),结合CONWIP投料规则和G/G/m排队网络模型,开发了一种确定半导体晶圆制造系统中合理在制品(WIP)水平的启发式算法.仿真实验结果表明,在系统中保持该算法所计算出的WIP水平,在一定的瓶颈设备处理时间波动范围内可以取得合理的TH和CT.

  19. 卵子线粒体老化——辅助生殖技术面临的瓶颈%Oocyte Mitochondiral Aging——Bottleneck of Assisted Reproductive Technology (ART)

    Institute of Scientific and Technical Information of China (English)

    汤江静; 尹萍; 邵敬於; 段涛; 滕晓明; 韩毅冰

    2013-01-01

    卵子老化是辅助生殖失败的一个重要原因.目前,许多妇女生育年龄不断推迟,导致卵 子老化问题日益严重.线粒体是细胞中提供能量的重要细胞器,体细胞衰老与线粒体功能异常密切相关.由于线粒体是卵子/胚胎中数量最多的细胞器,推测线粒体功能的损伤可能在卵子老化、受精成功率和体外胚胎发育方面,也起到重要作用.本文根据前人的研究成果,阐述了线粒体在卵子成熟、受精以及胚胎发育过程中的作用,分析了线粒体老化对卵子质量和受精胚胎发育的影响,证明提高卵母细胞中线粒体功能,对提高卵母细胞/体外受精胚胎的质量具有重要的意义.%"Oocyte aging" is an important cause for IVF failure and poor embryo quality. At present, many women delay their pregnancy to the later part of their childbearing years which makes "oocyte aging" a more important etiology for infertility. Mitochondrial dysfunction is associated with somatic cells senescence. Because mitochondria are the most abundant organelles in oocytes/embryos, we speculate that mitochondrial dysfunction may have an important role in oocyte maturation, fertilization and embryo development too. In this article, we have reviewed the function of mitochondria during oocyte maturation, fertilization and the following embryo development. Techniques improving mitochondrial function in the oocytes could not only prevent the oocyte aging process, but also improve the quality of embryos from assisted reproductive technology (ART).

  20. Solution on the Five Major Bottleneck Problems in the legal Construction of ecological civilization%破解生态文明法制建设的五大瓶颈问题

    Institute of Scientific and Technical Information of China (English)

    杨朝霞

    2014-01-01

    在我国生态文明法制建设过程中,我们不得不面对资源约束趋紧、环境污染严重、生态系统退化等一系列严峻形势.在传统文明向生态文明的时代拐点上,本文深刻分析制约我国生态文明法制建设的五大关键点,并提出合理有效对策.

  1. Analysis on Application Bottleneck of Repairing Bone Defects with Tissue Engineered Bone%组织工程骨修复骨缺损的应用瓶颈分析

    Institute of Scientific and Technical Information of China (English)

    李凯

    2012-01-01

    Bone defects caused by bone cancer treatment are common in clinical, however the only way to repair the defects is bone graft. According to sources, the bone graft material can be divided into autogenous bone, allograft bone ,xenograft bone and artificial bone substitute materials. The rise of bone tissue engineering brings new options for the treatment of bone defects. The use of artificial bone tissue engineering training not only fixes the large area of bone defect, but also can be prepared and shaped in large quantity according to need,which makes it an ideal bone repair material. Here is to make a review' on the application status of tissue engineered bone in the treatment of bone defects.%骨肿瘤的治疗导致骨缺损很常见,修复缺损的方法是采取骨移植.骨移植材料根据来源大致可分为自体骨、同种异体骨、异种骨和人工骨替代材料.骨组织工程的兴起为骨缺损的治疗带来新的选择.利用骨组织工程培养的人工骨不仅可以修复大面积骨缺损,而且可以按需塑形并大量制备,是一种理想的骨修复材料.现就组织工程骨在治疗骨缺损中的应用现状进行综述.

  2. 制造业突破库存管理瓶颈的方法及实证研究%Manufacturing Breakthroughs Inventory Management Bottleneck Method and Empirical Research

    Institute of Scientific and Technical Information of China (English)

    董鹏; 郭丽美

    2013-01-01

    At present through the analysis of domestic manufacturing inventory status and management ideas, to find the United States of America Carlisle companies finished inventory backlog of reason and the backlog of inventory to the production and operation of enterprises brought bad influence. Combined with examples of Calais companies to reduce inventory, points out that the application of management by objectives, fishbone diagram, ABC classification management tool, is the most effective method to reduce the inventory. This succeeded in reducing inventory, related to the manufacturing industry for effective inventory management to provide reference.%  要:通过分析目前国内制造业的库存现状及管理思路,找出美国卡莱公司造成成品库存积压的原因及库存积压给企业生产经营带来的不良影响。结合卡莱公司降低库存的实例,指出运用目标管理、鱼骨图、ABC分类等管理工具,是降低库存的最有效方法。本次成功地降低了库存量,为相关制造业进行有效的库存管理提供借鉴。

  3. T he Reality Bottleneck and Breakthrough Path of T eachers'Virtual Living%教师虚拟生存的现实瓶颈与突围路径

    Institute of Scientific and Technical Information of China (English)

    罗儒国

    2015-01-01

    教师虚拟生存是教师为了生命发展与完善、实现生存价值与意义、提高生存质量,以各种数字化符号为中介,在虚拟世界或网络世界中进行的有目的、有意识的生存活动。然而,作为一种新型生存方式,教师虚拟生存的崛起虽然有其历史必然性与现实合理性,但也面临着教师虚拟生存意愿较为淡薄、虚拟生存能力亟待提高、虚实共生机制尚未形成、教师虚拟生存制度不够完善、虚拟生存技术条件不够成熟等方面问题。为此,需要引导教师正确认识虚拟生存价值、增强教师虚拟认同意识,加强教师教育技术培训、提升教师网络生存素养,确立虚实共生的生存图景、建立虚实和谐共生机制,强化学校信息文化建设、营造良好文化环境,以便推动教师虚拟生存的健康、有序发展。%Teachers'virtual living refers to all kinds of living activities carried by teachers in the cyber world or virtual world by digital symbols , which are aimed at developing and improving life , promoting life quality and realizing the value and significance of life . However , as a new‐type of living style , the rise of teachers'virtual living has its ow n historical inevitability and real rationality , but it also encounters some realistic plights and embarrassments which mainly involve lack of strong virtual living will , lack of digital survivability , lack of symbiotic system between virtual living and realistic living , lack of security system of teachers'virtual living . Therefore , it is necessary to have a correct understanding of virtual living value , strengthen teachers' virtual living identity , reinforce teachers' pedagogical technology training ,improve teachers'cyber living quality ,promote interaction and interpenetration between virtual living and realistic living , build an ideal virtual reality living pattern , enhance information culture construction , create a fine culture environment , so as to promote a sound development of teachers'virtual living .

  4. 历史文化街区的市政工程技术规范瓶颈与对策%BOTTLENECK AND STRATEGY OF MUNICIPAL ENGINEERING SPECIFICATION IN HISTORIC CONSERVATION AREA

    Institute of Scientific and Technical Information of China (English)

    李新建; 朱光亚

    2012-01-01

    我国历史文化街区缺乏专门的市政工程技术规范,保护规划实践往往因套用现行一般市政工程技术规范而导致偏差.通过分析我国现行市政工程技术规范和标准以“指令性”的具体技术手段和参数为主、适应性和灵活性不足的缺陷,指出历史文化街区应制定适应其物质空间特性和遗产保护要求的专门的“性能化”市政工程技术规范,与一般城市建设标准保持“适度差异”,并提出实现这一目标的法规和管理对策.%In China,historic conservation area has not pertinent technique specification for its municipal engineering, and its conservation is always harmed by mechanical application of existing generic specification of urban construction, which is prescriptive-based and inadaptable to heritage conservation. Municipal engineering in historic conservation area needs special performance-based technique specification, which is allowably different from those generic standards and requires some legislative and administrant measures to put in practice.

  5. Research on Bottlenecks and Countermeasures of University Students' Employment Under the Background of the Financial Crisis%金融危机背景下的大学生就业瓶颈及对策研究

    Institute of Scientific and Technical Information of China (English)

    曹广喜

    2011-01-01

    在金融危机背景下,由于大学生毕业人数猛增、大学生就业结构性矛盾、大量留学生回归等原因,使大学生就业难问题更加凸显出来,已经成为社会关注的热点和难点问题.对大学生就业现状和就业瓶颈及其解决途径进行系统研究,以期为当前大学生就业难问题提供一些对策建议.

  6. 民族传统体育高脚马运动发展瓶颈分析%On Bottlenecks of Development of Chinese Minority Traditional Sports Event "Horse on Stilts"

    Institute of Scientific and Technical Information of China (English)

    陈辉

    2012-01-01

    Chinese minority traditional sports event "Horse on Stilts" through a decade of development, the speed isamazing. 100 m and 200 m performance level has been running close to or above the results, but fn the relay rules of project requirements and project settings for a single, always influence and restrict "Horse on Stilts" sports development space. According to previous project of the national democratic movement's "Horse on Stilts" relay performance analysis,combination with Hong he Pl:efecture of Yunnan province athletes run and "horse on stilts" run'to the tests, As welu as in "horse on stilts" project settings on thinking. The current "Horse on Stilts" relay race rules, the project set up research and analysis, attempt to explore the development of "Horse on Stilts" movement favorable factors, and the formation of scientific theory to guide the development of "Horse on Stilts" movement.%民族传统体育高脚马运动在近十年的竞技发展中,其发展速度是惊人的,100米和200米成绩已接近甚至超过了平跑成绩,但接力跑项目的规则要求和项目设置的单一,始终影响和制约着高脚马运动发展的空间,笔者根据历届全国民运会高脚竞速接力项目成绩的分析,并结合云南省红河州高脚竞速运动员平跑与高脚跑的各项测试,以及在高脚马项目设置上的思考,对现有高脚竞速接力跑竞赛规则、项目设置进行研究分析,试图探索出高脚马运动发展的有利因素,并形成科学理论指导高脚马运动的发展。

  7. On the elimination of the electronic structure bottleneck in on the fly nonadiabatic dynamics for small to moderate sized (10-15 atom) molecules using fit diabatic representations based solely on ab initio electronic structure data: The photodissociation of phenol

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaolei, E-mail: virtualzx@gmail.com; Yarkony, David R., E-mail: yarkony@jhu.edu [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States)

    2016-01-14

    In this work, we demonstrate that for moderate sized systems, here a system with 13 atoms, global coupled potential energy surfaces defined for several electronic states over a wide energy range and for distinct regions of nuclear coordinate space characterized by distinct electron configurations, can be constructed with precise energetics and an excellent description of non-adiabatic interactions in all regions. This is accomplished using a recently reported algorithm for constructing quasi-diabatic representations, H{sup d}, of adiabatic electronic states coupled by conical intersections. In this work, the algorithm is used to construct an H{sup d} to describe the photodissociation of phenol from its first and second excited electronic states. The representation treats all 33 internal degrees of freedom in an even handed manner. The ab initio adiabatic electronic structure data used to construct the fit are obtained exclusively from multireference configuration interaction with single and double excitation wave functions comprised of 88 × 10{sup 6} configuration state functions, at geometries determined by quasi-classical trajectories. Since the algorithm uses energy gradients and derivative couplings in addition to electronic energies to construct H{sup d}, data at only 7379 nuclear configurations are required to construct a representation, which describes all nuclear configurations involved in H atom photodissociation to produce the phenoxyl radical in its ground or first excited electronic state, with a mean unsigned energy error of 202.9 cm{sup −1} for electronic energies <60 000 cm{sup −1}.

  8. 中高职数学课程衔接的瓶颈及其对策%The Bottle-neck of Curriculum Articulation of Mathematics in Secondary School and Higher Vocational School and Its Countermeasures

    Institute of Scientific and Technical Information of China (English)

    万里亚

    2014-01-01

    课程衔接是中高职教育衔接的核心与关键,针对数学课程衔接中的诸多问题,必须从课程标准、课程结构、课程教学、学生学习方法等方面采取有效措施,才能实施中高职数学课程的有效衔接。%Curriculum articulation is the essence and the core of secondary school education and higher vocational education. As to many problems related to curriculum articulation of mathematics, we should take measures to efficiently implement the plan of curriculum articulation of mathematics on aspects of curriculum syllabus, curriculum structure, curriculum teaching and students' learning strategy in secondary and higher vocational school.

  9. 在校大学生创业融资瓶颈探析--以内江师范学院为例%Analysis on Financing Bottleneck of Undergraduate Students in Entreprenaurial Process--The Case of Neijang Normal College

    Institute of Scientific and Technical Information of China (English)

    王丹; 李达伟

    2016-01-01

    In recent years, the government provided undergraduate students with entrepreneurship policy support, and the schools also made detailed work for student entrepreneurship. But undergraduate students in the actual entrepreneurship process still face many difficulties, among of which venture capital shortage is the biggest problem. Thus, the entrepreneurs themselves should take an active part in all kinds of project funds and entrepreneurship competition for funds. Meanwhile, the government should further strengthen the policy support, school authorities should provide auxiliary support, entrepreneurs, government and schools should cooperate, jointly creating a good financing environment for undergraduate students venture.%近年来,政府为大学生创业提供了政策支持,学校也为学生创业做了细致深入的工作,但在校大学生在实际创业过程中还是面临重重困难,其中创业资金短缺是最大问题。对此,创业者自身应积极参与各种项目基金和创业竞赛获取资金,同时政府应进一步强化政策支持,学校应提供辅助支持,创业者、政府、学校三方通力合作,共同为在校大学生创业营造良好的融资环境。

  10. Widening a Bottleneck: Towards a Better Patient Flow in Health Services : An analysis of utilization of specialized health services for diagnose-groups at the municipality level. Studied period from years 1999 to 2007

    OpenAIRE

    2010-01-01

    BACKGROUND: The coordination reform is currently a hot political topic. Part of the reform’s delivery arrangements is related to the expansion of municipal health services. This aims to relocate health services and increase the municipalities’ share of responsibility. Financial measures are also proposed to support the other policy arrangements. Before these policies are introduce, it is important to see if an expansion and relocation of health services to the municipalities reduce the use of...

  11. 网络信息检索技术现状、瓶颈及趋势分析%The Present Condition, Bottleneck and Trend Analysis of the Information Retrieval Technique on Network

    Institute of Scientific and Technical Information of China (English)

    龚蛟腾

    2004-01-01

    目前网络信息检索技术主要有资源定位检索技术、超链接搜索技术、网络搜索引擎技术及通用信息检索技术,制约网络信息检索技术发展的瓶颈是图像音频视频检索、汉语自动切分、搜索引擎缺陷等.智能检索技术、知识检索技术、多媒体检索技术、新一代搜索引擎技术、自然语言检索技术和基于内容的检索技术是网络信息检索技术发展的核心与关键.

  12. Breakthrough Stroke of the Chinese Character Input Shape Code on Double Innovation Bottleneck%突破汉字输入瓶颈的双创新笔形码

    Institute of Scientific and Technical Information of China (English)

    李静波; 胡锡全

    2011-01-01

    Shape code is tool of not only inputing but also learning and practicing Chinese.This code names key on keyboard as line and row.%形码既要输入汉字,也应是学习、练习汉字的工具。本码对键盘的键使用行列称呼。

  13. 浅谈90后中职生德育工程瓶颈及策略%On Moral Education Project Bottlenecks and Strategies of Post-90s Vocational Students

    Institute of Scientific and Technical Information of China (English)

    关晶

    2014-01-01

    随着离婚率的日趋增多,基于离异、重组家庭的问题型中职生比例无可回避地随之攀升。直面90中职生现在的掩贫炫富、两极差异、愤青心理、早恋泛滥、感情转移、不知感恩等德育现状,中职学校惟其以人为本、追根溯源、携手家长、综合纠偏,方为标本兼治之策。%With the divorce rate is increasing, the proportion of problem-based vocational students of divorced, remarried families is also unavoidable to subsequently rise. Based on the moral education situation of now post-90s vocational students that covering poor showing off wealth, poles differences, angry youth psychology, puppy love flooding, emotional transformation and ungrateful, vocational college should adhere to the people-oriented, track the source, work with parents and comprehensive correction to solve these problem.

  14. 基于元胞自动机的高速公路临时瓶颈交通流仿真%Simulation of Temporary Traffic Bottleneck on Highways Based on Cellular Automaton

    Institute of Scientific and Technical Information of China (English)

    江欣国; 夏亮

    2016-01-01

    为研究强制换道及冲突点分布对高速公路临时瓶颈交通流的影响,在NS(NaSch)模型和STCA (symmetric two-lane cellular automata)模型的基础上,引入强制换道规则,根据瓶颈口上游驾驶员心理状态的变化,建立高速公路瓶颈交通流模型.在开口边界条件下,针对不同的安全换道概率、强制换道概率、冲突点距离和冲突区间长度参数,模拟得到瓶颈交通流量和换道频率与车辆到达率的关系.仿真结果表明,安全换道行为对系统流量影响小;强制换道行为是降低瓶颈系统最大流量的主要因素,当安全换道概率为0.5时,强制换道概率从0.0增加至0.1,最大流量下降了17%;冲突点距离的增加缓解了交通拥堵程度,当冲突点距离从1 cell增加至4 cell时,临界车辆到达率上升了4%;冲突区间长度对交通事故风险的影响较大,最大强制换道频率随冲突区间长度的增加而增加.

  15. “Ten No”Bottlenecks Should Be Broken for Achieving Universal Health Care%全民医保亟待打破“十不”瓶颈

    Institute of Scientific and Technical Information of China (English)

    田芬

    2014-01-01

    我国基本实现全民医保,但必须清醒地看到,目前的全民医保存在着制度不统一、管理归属不明确、经办不标化,权利义务不对等,社保商保不分,对“病”的界定不清,购买服务界线不清,本地异地就医不分,风险预测不清,供需不平衡,对欺诈骗保打击不力,税费不分等问题,亟待加快治理体系和治理能力现代化。%We have basically achieved the goal of universal health care in China. However, it must be clearly realized that there are still problems such as inconsistence in systems, unclear classification in management departments, non-standardized professional criteria for insurance agencies, non-equivalence in right and duty, non-differentiation in social insurance and commercial insurance, unclear definition of “diseases”, unclear limitation in purchasing service, unclear definition in accessing local or offsite health services, unclear risk prediction, imbalance in demands and supplies, inefficiency in combating insurance fraud, unclear definition in taxes and fees. It is also urgent to accelerate the modernization of administrative system and governance capacity.

  16. An Empirical Study for Identifying Traffic Breakdown at Bottlenecks%基于车道的瓶颈交通流失效识别实证研究∗

    Institute of Scientific and Technical Information of China (English)

    李晓庆; 王忠宇; 陈可心; 吴兵

    2015-01-01

    交通流失效识别是确定交通状态、制定交通管理策略的关键。为精细化识别各车道交通状态的差异,提出以车道为基础,利用速度变形累积曲线将每个时间间隔内的速度波动"转折点"放大,较为精确和直观地确定各车道的瓶颈交通流失效时间。相比于以往基于断面和基于阈值的识别方法,该方法更为精细和客观,不仅能有效识别路段的半拥挤状态,也可以深入分析拥挤的横向、纵向传播特性。以上海市快速路军工路出口匝道附近作为研究对象,结果表明,出口匝道附近的拥挤一般先由最外侧车道开始,平均经4 min 之后扩散到最内侧车道,但在向上游纵向蔓延的过程当中,内侧车道反而比外侧车道更容易发生交通拥挤。%Identification of traffic breakdown is critical for evaluating traffic flow states and making decision on traf-fic operation plan.In order to detect the differences of traffic conditions among the lanes in detail,a lane-based method is proposed,which is able to identify breakdown accurately and in an intuitive way.The occurring time of traffic breakdown is determined by enlarging the"turning point"of speed fluctuations at each time interval using speed transform cumulative curve.Compared to the traditional section-based and threshold-based methods,the proposed lane-based method is more accurate and objective which can not only differentiate the semi-congested states,where only some of lanes are congested, but also show the longitudinal and transverse propagation characters of traffic congestion in depth.The off-ramp at the Jungong Expressway Road in Shanghai is used as a case study and the results show that the breakdown actually occurs on the outermost lane firstly and then spread to innermost lane after an average of 4 minutes.When the congestion propa-gates to the upstream,the inner lanes tend to be more congested than the outer lanes.

  17. The Congestion Control Algorithm of PID Based on the ATM Network Model of Single Bottleneck%基于ATM单瓶颈节点模型的PID拥塞控制器设计

    Institute of Scientific and Technical Information of China (English)

    关新平; 刘志新; 龙承念

    2004-01-01

    针对ATM单瓶颈节点网络模型,提出ABR业务拥塞控制方案,给出使系统闭环稳定PID参数应满足的约束条件.设置前馈环节以抑制带宽波动对缓冲区队列长度的影响.仿真结果表明,业务服务质量得到了保证,系统具有较好的动态性能.

  18. 基于瓶颈模型的交通拥堵收费与补贴模式研究%Dynamic Congestion Pricing with Subsidy from Revenue Based on Bottleneck Model: An Approach Focused on Efficiency and Equity

    Institute of Scientific and Technical Information of China (English)

    魏鑫; 宗刚

    2015-01-01

    为了既保证交通拥堵收费的效率又降低个人出行者的出行成本,使得社会和个人利益能有效统一并提高公众对拥堵收费的接受度,基于双通道瓶颈模型设立了拥堵收费与补贴相混合的模式,将收费路段的收费收入全部或部分补贴到免费路段上.进而我们对该模式的参数和效果进行算例分析,发现该模式可以有效地减缓交通拥堵.同时模式与一般动态单通道收费相比在社会成本缩减方面仅有微小劣势,但却使得小汽车出行者的成本大幅缩小,公平度有显著提升.最后根据算例分析结果的比较,给出了方法最适用的情况

  19. 多延迟多瓶颈网络拥塞鲁棒控制研究%The Study on Multi-Delay and Multi-Bottleneck Network Congestion Robust Control

    Institute of Scientific and Technical Information of China (English)

    单纯; 陈晓龙

    2009-01-01

    研究了具有多延迟用户源端和多瓶颈链路端的复杂网络的主动队列管理控制器的设计和稳定性分析.建立了具有非线性、输入带有时滞和不确定参数扰动的通用网络TCP/AQM动态模型.在平衡点线性化后,采用还原算法进行延迟补偿和预估,将该模型转化为无时滞的线性模型.在系统状态矩阵和输入矩阵参数扰动不满足匹配但有界的条件下,采用积分滑模变结构控制算法,基于Lyapunov稳定性理论和线性矩阵不等式方法给出了滑模可到达和渐进稳定的可行条件,根据该条件设计鲁棒主动队列管理算法.理论证明了该算法的稳定性.

  20. The "Bottleneck" of Human Capital Which Influences the Economic Growth in the West and the Countermeasures%制约西部经济增长的人力资本"瓶颈"及对策

    Institute of Scientific and Technical Information of China (English)

    景跃军; 吴云龙

    2003-01-01

    国民收入的某些重要增长是由于增加了教育投资这种人力资本而造成的,经济增长主要来源于人力资本储量的增长.在阐述了人力资本投资与经济增长的关系后,以数据分析了西部资本结构与人力资本问题,最后给出了加速西部人力资本积累,促进西部经济增长的对策.

  1. Research on the Bottleneck Problem of China’s Cross-Border Electronic Commerce%中国跨境电子商务发展的“痛点”分析

    Institute of Scientific and Technical Information of China (English)

    文瑞

    2015-01-01

    近年来,随着经济全球化和电子商务的快速发展,跨境电子商务成为国际贸易的新方式。相较于传统贸易,中国跨境电子商务交易规模不断扩大,并保持连续性的高速增长,但同时,跨境电子商务也面临着诸如支付、物流、报关、商检、售后等诸多“痛点”。因此,亟需通过建设跨境电子商务产业园区,创新跨境物流服务,发挥跨境创牌优势,培养全面发展型人才,重构跨境电子商务适用规则等措施来推动中国跨境电子商务进一步的发展。%Recently,cross-border e-commerce became the new way of international trade with economic globalization and the rapid development of electronic commerce. Compared with the traditional trade,China’s cross-border e-commerce transactions expand continually and keep the continuous high-speed growth. At the same time,cross-border e-commerce is faced with some pain points such as payment,logistics,customs clearance,commodity inspection and after sales. Therefore, we urgently need to take some measures,like the construction of cross-border e-commerce industrial park,cross-border logistics service innovation,giving full play to the advantages of cross-border brand,cultivating comprehensive talent, refactoring applicable cross-border e-commerce rules,so as to promote the further development of Chinese cross-border electronic commerce.

  2. 中国科技期刊开放获取的瓶颈问题分析%Bottlenecks of open access for sci-tech journals and its countermeasures

    Institute of Scientific and Technical Information of China (English)

    田海江; 李若溪

    2013-01-01

    Nowadays, the open access of Chinese sci-tech journals to some problems that exist in the development and study of the status quo, editors and readers do not have a comprehensive understanding of the concept and the lack of policy support for rapid development and open access within the industry funds support, lack of open access aspects of professional talent. With extensive investigation and statistical analysis to find the root of these problems, and proposed the corresponding countermeasures and suggestions.%通过对我国科技期刊开放获(OA)取发展现状的研究发现,编者、读者对OA并没有全面的认识,对其长足发展缺乏政策支持,行业内部的资金支撑不足,缺乏OA方面的专业人才.通过广泛调查统计分析,找出了这些问题的根结,并提出了相应的对策和建议.

  3. How to Breakthrough the Bottleneck of the Development of Animation Specialty in Colleges%谈如何突破高校动漫专业发展的瓶颈

    Institute of Scientific and Technical Information of China (English)

    佘东; 周守东

    2012-01-01

      According to the analysis of the animation specialty development situation, employment characteristics of graduates and animation employee demand, we put forward some suggestions on animation specialty development, such as strengthening innovation education , paying attention to the animation scene localization and culturing The inclusive education concept of the ACG. We establish project teaching as the core of the reform of training scheme, and finally we can find the methods of solving the development problem of animation specialty.%  通过分析动漫专业发展现状,结合毕业生就业特点和动漫专业需求分析进行问题剖析,提出了加强创新教育,注重动漫场景本土化,培养ACG时代的融合教育理念,建立以项目式为核心人才培养方案改革,解决动漫专业发展瓶颈的方法。

  4. 上海实施邮轮岸电的瓶颈与对策建议%Bottleneck and Countermeasures of Implementation of the Cruise Ship Shore Power in Shanghai

    Institute of Scientific and Technical Information of China (English)

    汪传旭

    2016-01-01

    邮轮的岸电使用已成为世界邮轮母港的通行做法,而上海借鉴制定邮轮岸电的国际化通行标准,有助于提升自身邮轮码头的国际竞争力.因此,从港口形象、邮轮岸电减排特点和提升港口国际竞争力角度来看,制定一套上海实施邮轮岸电的先行先试政策,有助于解决交通发展与日益严峻的港口环境之间的矛盾,以提高上海国际邮轮母港绿色标准的国际影响力.

  5. 制约高职院校体育课程建设的瓶颈与对策研究%Restriction of Physical Education in Higher Vocational Colleges Construction Bottleneck and Countermeasure Research

    Institute of Scientific and Technical Information of China (English)

    邱玉琴

    2012-01-01

    In order to deepen the teaching reform,comply with the development of the times,advancing the construction of physical education curriculum in higher vocational colleges,analyzed the crux of the curriculum construction in higher vocational colleges,the construction of physical education curriculum value orientation and main countermeasures,so as to promote the harmonious development of students’ body and mind.%为深化教学改革,顺应时代发展,推进高职院校体育课程建设,分析影响课程建设的症结所在,研究高职院校体育课程建设的价值导向与主要对策,从而促进学生身心和谐全面发展。

  6. Genetic evidence for population expansion in Hydrotaea irritans (Fallèn) (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Loeschcke, V.; Nielsen, B. O.; Pedersen, A. Aa.;

    2004-01-01

    geographic variation, F-statistics, allozyme electrophoresis, skewed allele frequencies, bottleneck, population expansion......geographic variation, F-statistics, allozyme electrophoresis, skewed allele frequencies, bottleneck, population expansion...

  7. Dynamic Characteristics of Explicit Control Protocol

    Institute of Scientific and Technical Information of China (English)

    CHENG Shuang-mei; LI Jian-hua; GUO Chuan-xiong

    2008-01-01

    The dynamic characteristics of eplicit control protocol (XCP) were investigated with single bottle-neck on the microscopic time-scale. Analysis and simulation results show that the bandwidth utilization of an XCP bottleneck link converges to 1 at exponential rate, persistent congestion cannot occur at the bottleneck link, and throughput of an arbitrary subset of XCP flows at the bottleneck link converges to its fair share in exponential rate. The XCP has high bandwidth utilization and good fairness properties.

  8. The Main Bottlenecks and Breakthrough of Ideological and Political Work Team Construction of in Private Colleges under the New Situation%新形势下民办院校思想政治工作队伍建设的主要瓶径及其突破

    Institute of Scientific and Technical Information of China (English)

    刘国辉

    2015-01-01

    In the current educational environment,the ideological and political work has become an important factor affecting the stability and development of private colleges.To build a group of strong ideological and political education work practition-ers is the key of colleges students'ideological and political work.This paper analyzes the status of current educational environ-ment,the ideological and political education practitioners team of private colleges and their roles to make approaches and meth-ods of building private colleges ideological and political work,as a reference for further strengthening and improving ideological and political works of private colleges.%在当前形势下,民办院校思想政治工作已经成为影响民办院校稳定与发展的重要因素,建设一支强有力的思想政治教育工作队伍是民办院校做好大学生思想政治教育工作的关键。本文通过分析当前形势和民办院校大学生思想政治教育工作队伍的现状,以及民办院校思想政治工作队伍的地位作用,提出民办院校思想政治工作队伍建设的主要途径和方法,为进一步加强和改进民办院校大学生思想政治工作提供一些借鉴和思考。

  9. Breaking the Bottleneck of Behaviour Change:Experience of Australia's Good Life Club and Implication for Chinese Community Health Services%突破行为改变的瓶颈——澳大利亚的美好生活俱乐部及其对中国社区卫生服务的启示

    Institute of Scientific and Technical Information of China (English)

    Shane Thomas; Colette Browning; 杨辉; 张拓红; 李志新

    2009-01-01

    包括糖尿病在内的大多数慢性疾病,需要患者通过改变自身行为来更好地管理疾病.国际研究经验表明,各种改变行为的活动都能明显地改善患者的健康,如改善饮食、降低体质量、增加锻炼、戒烟、降低压力、监测血糖、监测足部和溃疡、按医嘱服药等.不过,即便患者已经有了足够的健康知识,他们也很难改变自己的行为,这在老年人身上表现得尤其明显.澳大利亚政府支持的美好生活俱乐部项目,采用健康教练服务的方式,帮助患者有效地改变行为,更好地管理糖尿病.现在澳大利亚很多慢性疾病管理服务中都采用了这种教练方式.美好生活俱乐部的主要参与者是生活在墨尔本市东部的澳大利亚本地和华裔人群,白马市的全科医学分会以及各社区服务中心和全科医生是该项目的合作伙伴,Monash大学和澳大利亚心理学会提供技术支持.美好生活俱乐部的设计采用行为改变阶段理论,教练采用心理学的动机谈话技术帮助患者发现内心矛盾、制定行动策略、促进行为改变.对该项目的评价结果表明,糖尿病患者的生活质量得到了显著和稳定的改变,更积极地参与包括走路在内的身体锻炼,加强了对自身血糖的管理,并能有效地监测糖尿病症状.本文讨论美好生活俱乐部的设计逻辑以及对该项目的主要评价结果,为中国社区的慢性疾病管理提供有益的借鉴.%Many illnesses including diabetes require the patient to modify their behaviour to manage their illness better.Knowing from international research that various actions will frequently result in major improvements in the health and well-being of the patient,such as change in diet (reducing fatty food,increasing fibre),lose weight,increasing physical activity and exercise,stop smoking,reduce stress,monitor blood sugar,monitor feet for sores and ulcers,and take prescribed medication.However,for most patients especially adult and elders,changing behaviour is enormous difficulty,although they have been well educated in patient education program.The Good Life Club was one of several chronic illness self-management programs funded by the Australia Government under the national Sharing Health Care initiative.It used clinical coaches to help patients effectively change their behaviours and better manage their diabetes.Many health services in Australia now routinely use this approach in chronic illness management.The key participants in the Good Life Club were patients with diabetes living in the east of Melbourne and were from Australian and Chinese backgrounds.The Club was a partnership between the Whitehorse Division of General Practice and various community health centres and private doctors.Monash University and Australian Psychological Society provided expert technical support to the Club.The Good Life Club used stages of change in the program design.Health coaches helped patients in motivational interviewing,a psychological technique that has been used internationally in managing people with chronic illness.The Club was closely monitored in order to validate effects of coaching.The participants demonstrated significant sustained positive changes in quality of life,and demonstrated a sustained involvement in walking exercise over the program and improved their management of blood sugar levels,and monitoring of diabetes symptoms.This article discusses logic and design of the Good Life Club and explores opportunity and implication for China′s community.

  10. 我国第三方物流发展瓶颈与营销策略的创新——4Ps理论在物流行业的运用%China's Third Party Logistics Development Bottleneck and the Innovation of the Marketing Strategy——4Ps theory use in the logistics industry

    Institute of Scientific and Technical Information of China (English)

    郑文玲

    2014-01-01

    近年来,我国经济取得突飞猛进的发展,产业结构获得了升级与优化,物流行业特别是第三方物流行业在我国经济发展中的地位越来越重要.然而,由于起步较晚、经验不足,我国第三方物流还存在很多缺陷.在对第三方物流业的现状与发展瓶颈进行分析的基础上,以市场营销学经典理论——4Ps战略模型对我国第三方物流企业的发展提供了一个可以借鉴的改进方案.

  11. 传统劳动密集型产业集群突破发展瓶颈初探--以湖南省醴陵陶瓷产业集群为例%A Brief Enquiry Into How Traditional Labor-intensive Industries Can Break The Development Bottleneck--with ceramics industrial cluster in Liling, Hunan Province as an example

    Institute of Scientific and Technical Information of China (English)

    刘彪

    2013-01-01

      在后工业时代和后金融危机时代的双重背景下,我国传统劳动密集型产业是我国十分重要的产业面临严峻考验。对于不同类型的劳动密集型产业,将面临产业升级、转移、退出的选择。本文以醴陵陶瓷产业集群为例,从其外部环境、集群内部协作、企业自身约束、政策导向四方面分析其所存在的问题,并从短期、长期两个角度为醴陵陶瓷产业集群升级发展提出可行性建议。%In this post-industrial era and faced with the aftermath of the financial crisis, domestic traditional labor-intensive industries, which figure prominently in China’s economy, are presented with grim challenges. They all have to make a choice between industrial upgrade, exit and transfer depending on the type of industry they are in. This essay takes the ceramics industrial cluster in Liling County as an example and looks into the problems there through an analysis on four aspects, namely, its external environment, corporate self-restraint, coordination inside the cluster and policy guidance. It further provides a feasible suggestion from short-term and long-term perspectives on approaches to upgrading and developing ceramics industry in Liling.

  12. Collective dynamics of an inhomogeneous two-channel exclusion process: Theory and Monte Carlo simulations

    CERN Document Server

    Dhiman, Isha

    2015-01-01

    This work is devoted to the development of a novel theoretical approach, named hybrid approach, to handle a localized bottleneck in a symmetrically coupled two-channel totally asymmetric simple exclusion process with Langmuir kinetics. The hybrid approach is combined with singular perturbation technique to get steady-state phase diagrams and density profiles. We have thoroughly examined the role played by the strength of bottleneck, binding constant and lane-changing rate in the system dynamics. The appearances of bottleneck-induced shock, a bottleneck phase and Meissner phase are explained. Further, the critical values of bottleneck rate are identified, which signify the changes in the topology of phase diagram. It is also found that increase in lane-changing rate as well as unequal attachment, detachment rates weaken the bottleneck effect. Our theoretical arguments are in good agreement with extensively performed Monte Carlo simulations.

  13. The mechanism and operating system to solve the bottleneck of the cooperation among industry, university and research institute, and the revelation of the mechanism and operating system of finland national technical research centre to Chinese circumstance%突破产学研运行瓶颈的机制设计——芬兰国家研究中心运行机制及对我国的启示

    Institute of Scientific and Technical Information of China (English)

    朱杉; 陈洁

    2009-01-01

    通过时芬兰国家技术研究中心(Technical Research Centre简称VTT)功能角色定位的研究,深入分析了VTT的运行机制,研究总结了VTT解决芬兰产学研结合瓶颈问题的关键原因是其独特的角色定位与运行机制设计,指出了VTT在科技创新体系中所发挥的效用以及值得我圆借鉴的一些启示.

  14. 青年社会组织参与城市社区治理:发展形势、问题瓶颈与推进路径--基于上海青年社会组织社区参与的调查%The Development Situation,Bottleneck Problem and Pushing Approach for the Youth Social Organizations to Participate in the Urban Community Governance:Based on the Research of Shanghai Youth Social Organizations in Community Participation

    Institute of Scientific and Technical Information of China (English)

    刘春蕾

    2016-01-01

    青年社会组织有活力、敢创新,是推进城市基层社区治理的重要力量。上海青年社会组织在参与社区治理过程中融入协同治理思维,面对着“活动领域入基层、参与内容合需求、社会责任能支撑、共青组织善引领、网络媒体搭平台”的发展形势,但也面临着主体待发育、基层欠信任、关系待理顺、政策欠优化、平台不完善等挑战。进一步深化改革是保证青年社会组织社区参与的关键,要做到发育主体、形塑信任、凝聚共识、调整结构、完善政策、搭好平台,构建起平等协作的参与新模式,形成互利共赢的发展新格局。%Dynamic and innovative Youth Social Organizations are an important force in urban grass-roots community governance.According to the field investigation data,Shanghai youth organizations have been integrated into the thought of synergistic governance in the process of community governance partici-pation.Their activities have entered into the grass-roots community .Their participating contents can meet the demand and their social responsibilities can be supported.The communist youth league is good at leading,network media also provides the platform.They also faced some challenges mainly including:subj ect remains to develop;grassroots lack of trust;relationship remains to be clarified;policy needs to be optimized;the platform is imperfect and so on.To further deepen the reform is the key for youth social organization to participate,which needs developing the organization subj ects,reshaping the trust,building the consensus,adj usting the structure ,perfecting the policy and building the platform so as to build the e-qual cooperation for youth social organization in community participation,as well as to form the new pat-tern of mutual benefits and the shared development.

  15. 76 FR 38203 - Endangered and Threatened Wildlife and Plants; Amendment to the Draft Recovery Plan for the...

    Science.gov (United States)

    2011-06-29

    ..., establishing criteria for downlisting or delisting listed species, and estimating time and cost for... success, soil-borne diseases, habituation to captive conditions, and genetic bottlenecks. The...

  16. Trip-timing decisions with traffic incidents

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Lindsey, Robin

    2013-01-01

    This paper analyzes traffic bottleneck congestion when drivers randomly cause incidents that temporarily block the bottleneck. Drivers have general scheduling preferences for time spent at home and at work. They independently choose morning departure times from home to maximize expected utility...

  17. Development Path for Agricultural Modernization of Shaanxi Province from the Perspective of Technological Progress

    Institute of Scientific and Technical Information of China (English)

    Lufeng; DUAN

    2013-01-01

    The lag in technological innovation is a bottleneck for modern agricultural development,so technological progress is an inevitable path to break this bottleneck. On the basis of introducing theory of technological progress,this study presents 4 paths for promoting agricultural modernization development in line with current situations of agricultural development and technological progress in Shaanxi Province.

  18. Snapshot of E-Commerce's Opportunities and Threats

    NARCIS (Netherlands)

    Saanen, Y. A.; Verbraeck, Alexander; Sol, H.G.

    1999-01-01

    E-commerce offers opportunities to change the way of doing business. However fully utilizing these opportunities and overcoming the bottlenecks, requires more than just getting online. The currently low Internet trade volumes confirm this. This paper gives a snapshot of opportunities and bottlenecks

  19. Balancing between feasibility and relationship. Interventions to prevent dysfunctionality of conflict in public private partnership projects

    NARCIS (Netherlands)

    Lousberg, L.H.J.M.

    2011-01-01

    Research shows that there are many bottle-necks in Public Private Partnership (PPP) Projects in Dutch spatial development. Due to the specific properties of Public Private Partnerships, these bottle-necks can lead to dysfunctional conflicts which are damaging the project. Hence the question is: how

  20. Balancing between feasibility and relationship : interventions to prevent dysfunctionality of conflict in public private partnership projects

    NARCIS (Netherlands)

    Lousberg, L.H.M.J.

    2011-01-01

    Research shows that there are many bottle-necks in Public Private Partnership (PPP) Projects in Dutch spatial development. Due to the specific properties of Public Private Partnerships, these bottle-necks can lead to dysfunctional conflicts which are damaging the project. Hence the question is: how