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Sample records for admission control mechanism

  1. An Improved Call Admission Control Mechanism with Prioritized Handoff Queuing Scheme for BWA Networks

    NASA Astrophysics Data System (ADS)

    Chowdhury, Prasun; Saha Misra, Iti

    2014-10-01

    Nowadays, due to increased demand for using the Broadband Wireless Access (BWA) networks in a satisfactory manner a promised Quality of Service (QoS) is required to manage the seamless transmission of the heterogeneous handoff calls. To this end, this paper proposes an improved Call Admission Control (CAC) mechanism with prioritized handoff queuing scheme that aims to reduce dropping probability of handoff calls. Handoff calls are queued when no bandwidth is available even after the allowable bandwidth degradation of the ongoing calls and get admitted into the network when an ongoing call is terminated with a higher priority than the newly originated call. An analytical Markov model for the proposed CAC mechanism is developed to analyze various performance parameters. Analytical results show that our proposed CAC with handoff queuing scheme prioritizes the handoff calls effectively and reduces dropping probability of the system by 78.57% for real-time traffic without degrading the number of failed new call attempts. This results in the increased bandwidth utilization of the network.

  2. 28 CFR 541.47 - Admission to control unit.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Admission to control unit. 541.47 Section... INMATE DISCIPLINE AND SPECIAL HOUSING UNITS Control Unit Programs § 541.47 Admission to control unit. Staff shall provide an inmate admitted to a control unit with: (a) Notice of the projected duration...

  3. 28 CFR 541.47 - Admission to control unit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Admission to control unit. 541.47 Section 541.47 Judicial Administration BUREAU OF PRISONS, DEPARTMENT OF JUSTICE INSTITUTIONAL MANAGEMENT INMATE DISCIPLINE AND SPECIAL HOUSING UNITS Control Unit Programs § 541.47 Admission to control...

  4. Self-organized call admission control for optical communication networks

    NASA Astrophysics Data System (ADS)

    Zuo, Bing; Liu, Lei; Wu, Jian; Lin, Jintong

    2008-11-01

    Call Admission Control (CAC) is widely used in optical communication networks to reduce network congestion. However, the conventional CAC scheme recommended by International Telecommunication Union -Telecommunication Standardization Sector (ITU-T) has a serious deficiency under high traffic load. In this paper, the disadvantage of conventional CAC scheme is analyzed in detail, and a Self-organized Call Admission Control (SCAC) scheme is proposed to solve this disadvantage. This scheme is accord with the principle of self-organization system, so it can be easily implemented in practice. Numerical results show that the proposed scheme can improve the network performance to a great extent.

  5. A lexicographic approach to constrained MDP admission control

    NASA Astrophysics Data System (ADS)

    Panfili, Martina; Pietrabissa, Antonio; Oddi, Guido; Suraci, Vincenzo

    2016-02-01

    This paper proposes a reinforcement learning-based lexicographic approach to the call admission control problem in communication networks. The admission control problem is modelled as a multi-constrained Markov decision process. To overcome the problems of the standard approaches to the solution of constrained Markov decision processes, based on the linear programming formulation or on a Lagrangian approach, a multi-constraint lexicographic approach is defined, and an online implementation based on reinforcement learning techniques is proposed. Simulations validate the proposed approach.

  6. BARTER: Behavior Profile Exchange for Behavior-Based Admission and Access Control in MANETs

    NASA Astrophysics Data System (ADS)

    Frias-Martinez, Vanessa; Stolfo, Salvatore J.; Keromytis, Angelos D.

    Mobile Ad-hoc Networks (MANETs) are very dynamic networks with devices continuously entering and leaving the group. The highly dynamic nature of MANETs renders the manual creation and update of policies associated with the initial incorporation of devices to the MANET (admission control) as well as with anomaly detection during communications among members (access control) a very difficult task. In this paper, we present BARTER, a mechanism that automatically creates and updates admission and access control policies for MANETs based on behavior profiles. BARTER is an adaptation for fully distributed environments of our previously introduced BB-NAC mechanism for NAC technologies. Rather than relying on a centralized NAC enforcer, MANET members initially exchange their behavior profiles and compute individual local definitions of normal network behavior. During admission or access control, each member issues an individual decision based on its definition of normalcy. Individual decisions are then aggregated via a threshold cryptographic infrastructure that requires an agreement among a fixed amount of MANET members to change the status of the network. We present experimental results using content and volumetric behavior profiles computed from the ENRON dataset. In particular, we show that the mechanism achieves true rejection rates of 95% with false rejection rates of 9%.

  7. Medication reconciliation at patient admission: a randomized controlled trial

    PubMed Central

    Mendes, Antonio E.; Lombardi, Natália F.; Andrzejevski, Vânia S.; Frandoloso, Gibran; Correr, Cassyano J.; Carvalho, Mauricio

    2015-01-01

    Objective: To measure length of hospital stay (LHS) in patients receiving medication reconciliation. Secondary characteristics included analysis of number of preadmission medications, medications prescribed at admission, number of discrepancies, and pharmacists interventions done and accepted by the attending physician. Methods: A 6 month, randomized, controlled trial conducted at a public teaching hospital in southern Brazil. Patients admitted to general wards were randomized to receive usual care or medication reconciliation, performed within the first 72 hours of hospital admission. Results: The randomization process assigned 68 patients to UC and 65 to MR. LHS was 10±15 days in usual care and 9±16 days in medication reconciliation (p=0.620). The total number of discrepancies was 327 in the medication reconciliation group, comprising 52.6% of unintentional discrepancies. Physicians accepted approximately 75.0% of the interventions. Conclusion: These results highlight weakness at patient transition care levels in a public teaching hospital. LHS, the primary outcome, should be further investigated in larger studies. Medication reconciliation was well accepted by physicians and it is a useful tool to find and correct discrepancies, minimizing the risk of adverse drug events and improving patient safety. PMID:27011775

  8. Call Admission Control Scheme Based on Statistical Information

    NASA Astrophysics Data System (ADS)

    Fujiwara, Takayuki; Oki, Eiji; Shiomoto, Kohei

    A call admission control (CAC) scheme based on statistical information is proposed, called the statistical CAC scheme. A conventional scheme needs to manage session information for each link to update the residual bandwidth of a network in real time. This scheme has a scalability problem in terms of network size. The statistical CAC rejects session setup requests in accordance to a pre-computed ratio, called the rejection ratio. The rejection ratio is computed by using statistical information about the bandwidth requested for each link so that the congestion probability is less than an upper bound specified by a network operator. The statistical CAC is more scalable in terms of network size than the conventional scheme because it does not need to keep accommodated session state information. Numerical results show that the statistical CAC, even without exact session state information, only slightly degrades network utilization compared with the conventional scheme.

  9. 49 CFR 382.121 - Employee admission of alcohol and controlled substances use.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Employee admission of alcohol and controlled... SAFETY REGULATIONS CONTROLLED SUBSTANCES AND ALCOHOL USE AND TESTING General § 382.121 Employee admission of alcohol and controlled substances use. (a) Employees who admit to alcohol misuse or...

  10. Reduced Admissions for Acute Myocardial Infarction Associated with a Public Smoking Ban: Matched Controlled Study

    ERIC Educational Resources Information Center

    Seo, Dong-Chul; Torabi, Mohammad R.

    2007-01-01

    There has been no research linking implementation of a public smoking ban and reduced incidence of acute myocardial infarction (AMI) among nonsmoking patients. An ex post facto matched control group study was conducted to determine whether there was a change in hospital admissions for AMI among nonsmoking patients after a public smoking ban was…

  11. Call Admission Control on Single Node Networks under Output Rate-Controlled Generalized Processor Sharing (ORC-GPS) Scheduler

    NASA Astrophysics Data System (ADS)

    Hanada, Masaki; Nakazato, Hidenori; Watanabe, Hitoshi

    Multimedia applications such as music or video streaming, video teleconferencing and IP telephony are flourishing in packet-switched networks. Applications that generate such real-time data can have very diverse quality-of-service (QoS) requirements. In order to guarantee diverse QoS requirements, the combined use of a packet scheduling algorithm based on Generalized Processor Sharing (GPS) and leaky bucket traffic regulator is the most successful QoS mechanism. GPS can provide a minimum guaranteed service rate for each session and tight delay bounds for leaky bucket constrained sessions. However, the delay bounds for leaky bucket constrained sessions under GPS are unnecessarily large because each session is served according to its associated constant weight until the session buffer is empty. In order to solve this problem, a scheduling policy called Output Rate-Controlled Generalized Processor Sharing (ORC-GPS) was proposed in [17]. ORC-GPS is a rate-based scheduling like GPS, and controls the service rate in order to lower the delay bounds for leaky bucket constrained sessions. In this paper, we propose a call admission control (CAC) algorithm for ORC-GPS, for leaky-bucket constrained sessions with deterministic delay requirements. This CAC algorithm for ORC-GPS determines the optimal values of parameters of ORC-GPS from the deterministic delay requirements of the sessions. In numerical experiments, we compare the CAC algorithm for ORC-GPS with one for GPS in terms of schedulable region and computational complexity.

  12. HYDRAULIC SERVO CONTROL MECHANISM

    DOEpatents

    Hussey, R.B.; Gottsche, M.J. Jr.

    1963-09-17

    A hydraulic servo control mechanism of compact construction and low fluid requirements is described. The mechanism consists of a main hydraulic piston, comprising the drive output, which is connected mechanically for feedback purposes to a servo control piston. A control sleeve having control slots for the system encloses the servo piston, which acts to cover or uncover the slots as a means of controlling the operation of the system. This operation permits only a small amount of fluid to regulate the operation of the mechanism, which, as a result, is compact and relatively light. This mechanism is particuiarly adaptable to the drive and control of control rods in nuclear reactors. (auth)

  13. Decisive Routing and Admission Control According to Quality of Service Constraints

    DTIC Science & Technology

    2009-03-01

    in pn sn1 tn1 sn2 tn2 sny tny ⎞ ⎟⎟⎟⎟⎟⎟⎠ Where the each row in the matrix corresponds to the following i1...n = input file size of...Preemptive Congestion Control Code Snippet The Decisive Routing and Admission Control According to Quality of Service Constraints code snippet of reaction to...simulation snippet of reaction to forecasted state of the network. The Kalman filter queue has reached a stated level of 45% of its capacity and

  14. Effect of air pollution control on mortality and hospital admissions in Ireland.

    PubMed

    Dockery, Douglas W; Rich, David Q; Goodman, Patrick G; Clancy, Luke; Ohman-Strickland, Pamela; George, Prethibha; Kotlov, Tania

    2013-07-01

    and 1998 bans, adjusting for influenza epidemics, weekly mean temperature, and local admissions for digestive diagnoses. Mean BS concentrations fell in all affected population centers post-ban compared with the pre-ban period, with decreases ranging from 4 to 35 microg/m3 (corresponding to reductions of 45% to 70%, respectively), but we observed no clear pattern in SO2 measured as total gaseous acidity associated with the bans. In comparisons with the pre-ban periods, no significant reduction was found in total death rates associated with the 1990 (1% reduction), 1995 (4% reduction), or 1998 (0% reduction) bans, nor for cardiovascular mortality (0%, 4%, and 1% reductions for the 1990, 1995, and 1998 bans, respectively). Respiratory mortality was reduced in association with the bans (17%, 9%, and 3%, respectively). We found a 4% decrease in hospital admissions for cardiovascular disease associated with the 1995 ban and a 3% decrease with the 1998 ban. Admissions for respiratory disease were not consistently lower after the bans; admissions for pneumonia, chronic obstructive pulmonary disease (COPD), and asthma were reduced. However, underreporting of hospital admissions data and lack of control and comparison series tempered our confidence in these results. The successive coal bans resulted in immediate and sustained decreases in particulate concentrations in each city or town; with the largest decreases in winter and during the heating season. The bans were associated with reductions in respiratory mortality but no detectable improvement in cardiovascular mortality. The changes in hospital admissions for respiratory and cardiovascular disease were supportive of these findings but cannot be considered confirming. Detecting changes in public health indicators associated even with clear improvements in air quality, as in this case, remains difficult when there are simultaneous secular improvements in the same health indicators.

  15. Admissions Policies as a Mechanism for Social Engineering: The Case of the Bulgarian Communist Regime

    ERIC Educational Resources Information Center

    Boyadjieva, Pepka Alexandrova

    2013-01-01

    This article discusses admissions policies to higher education during the Communist regime in Bulgaria (1946-89). It argues that under the conditions of the Bulgarian Communist regime, admissions policies were not only a component of the higher education system--viewed as an institution--but part and parcel of the process through which power was…

  16. A nested case–control study to determine the incidence and factors associated with unanticipated admissions following day care surgery

    PubMed Central

    Singh, Madhurita; Ponniah, Manickam; Jacob, KS

    2016-01-01

    Background and Aims: Day care surgery offers respite from hospitalisation for specific surgical procedures and has many advantages. However, occasionally patients who undergo such surgery require hospitalisation for unanticipated complications. We aimed to determine their incidence and to identify factors associated with unanticipated admissions in a tertiary care hospital in South India. Methods: During the 3-month study, 63 cases requiring admission and 126 randomly selected controls were taken from the 776 procedures that were performed were compared. The variables studied were patients’ demographic characteristics, pre-operative medical illness, personal habits, American Society of Anesthesiologists status, the diagnosis and surgical procedures, time since last meal, duration of anaesthesia and surgery, experience of the surgeon and anaesthetist, and intraoperative management (techniques, drugs, monitoring, etc.). Univariate and bivariate statistics were used to determine factors associated with unanticipated admissions. Results: The incidence of unanticipated admissions following day care surgery was 8.11%. The reasons for admission were anaesthetic (33.33%), surgical (15.87%), medical (6.34%) and social (44.44%). The factors significantly associated with unanticipated admissions included duration of anaesthesia more than 50 min (odds ratio [OR]: 3.179; 95% confidence interval [CI]: 1.503–6.722), and starting the last case after 3 pm (OR: 10.095; 95% CI: 2.418–42.148). Conclusion: Unanticipated admissions following day care surgery occur mainly due to anaesthetic, surgical, medical and social reasons. PMID:27942057

  17. SIR-based call admission control for DS-CDMA cellular systems

    NASA Astrophysics Data System (ADS)

    Liu, Zhao; Elzarki, Magda

    1994-05-01

    Signal-to-interference ratio (SIR)-based call admission control (CAC) algorithms are proposed and studied in a DS-CDMA cellular system. Residual capacity is introduced as the additional number of initial calls a base station can accept such that system-wide outage probability will be guaranteed to remain below a certain level. The residual capacity at each cell is updated dynamically according to the reverse-link SIR measurements at the base station. A 2(sup k) factorial experimental design and analysis via computer simulations is used to study the impact of the parameters used in the algorithms. The influence of these parameters on system performance, namely blocking probability and outage probability, is then examined via simulation. The performance of the algorithms is compared together with that of a fixed call admission control scheme (fixed CAC) under both homogeneous and hot spot traffic loadings. The results show that SIR-based CAC always outperforms fixed CAC even under overload situations, which is not the case in FDMA/TDMA cellular systems. The primary benefit of SIR-based CAC in DS-CDMA cellular systems, however, lies in improving the system performance under hot spot traffics.

  18. Call admission control for CDMA systems with Interference Guard Margin (IGM)

    NASA Astrophysics Data System (ADS)

    Chen, Huan; Kumar, Sunil; Kuo, C.-C. Jay

    2002-01-01

    A call admission control (CAC) scheme and a resource-reservation estimation (RRE) method suitable for the interference-based wireless system, such as wide-band code division multiple access (W-CDMA), are proposed in this work. The proposed CAC scheme gives preferential treatment to high priority handoff calls by pre-reserving a certain amount of interference margin called the interference guard margin (IGM). The amount of guard margin is determined by the measurement performed by the RRE module in base stations. Each RRE module dynamically adjusts the level of guard margin by considering traffic conditions in neighboring cells based upon handoff requests. A service model is adopted to support multiple services, which includes mobile terminal's data rate, different levels of priorities, mobility and rate adaptivity characteristics. Simulations are conducted with OPNET to study the performance of the proposed scheme in terms of the objective function, blocking probabilities and system utilization under different traffic conditions.

  19. Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

    NASA Astrophysics Data System (ADS)

    Xu, Changchun; Xu, Yanyi; Liu, Gan; Liu, Kezhong

    Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

  20. Equality Based Flow-Admission Control by Using Mixed Loss and Delay System

    NASA Astrophysics Data System (ADS)

    Miyata, Sumiko; Yamaoka, Katsunori

    We have proposed a novel call admission control (CAC) for maximizing total user satisfaction in a heterogeneous traffic network and showed the effectiveness of our CAC by using an optimal threshold from numerical analysis [1]. In our previous CAC, when a new broadband flow arrives and the total accommodated bandwidth is more than or equal to the threshold, the arriving new broadband flow is rejected. In actual networks, however, users may agree to wait for a certain period until the broadband flow, such as video, begins to play. In this paper, when total accommodated bandwidth is more than or equal to the threshold, arriving broadband flows wait instead of being rejected. As a result, we can greatly improve total user satisfaction.

  1. Scheduling and Call Admission Control A WiMax Mesh Networks View

    NASA Astrophysics Data System (ADS)

    Câmara, Daniel; Filali, Fethi

    This chapter discusses the problem of providing call admission control (CAC), scheduling and band reservation for wireless networks. It presents the importance of such procedures focusing mainly on WiMax mesh mode networks. The chapter also classifies some of the most known proposals presented in the literature to solve the scheduling and CAC problems for this kind of network. Differently of some other standards, in the IEEE 802.16 standard the scheduling and CAC procedures are mandatory. No node in the network can communicate, even in the mesh mode, without having the transmission previously scheduled. In this way scheduling becomes one of the most important processes to achieve spectral efficiency and, in consequence, to increase the network capacity.

  2. Heterogeneous voice flows-oriented call admission control in IEEE 802.11e WLANs

    NASA Astrophysics Data System (ADS)

    Wu, Qi-lin; Huang, Zhen-jin; Wang, Shi-yi

    2014-04-01

    Considering the circumstance of heterogeneous voice flows, first, by applying Markov chain, this paper proposes an unsaturated analytical model for the IEEE 802.11e EDCA protocol, which considers the condition of non-ideal transmission channel and the character of the occurrence of backoff countdown at the beginning of time slot in EDCA protocol. Furthermore, according to the proposed model, the media access delay and throughput of a flow are analysed, and the flow-oriented call admission control (CAC) scheme is proposed. Finally, the simulation results are shown to confirm that the proposed CAC scheme can guarantee the requirements of throughput and delay of voice flows, and can admit more voice flows to improve the utilisation efficiency of network resources by choosing the appropriate values of the minimum contention window or the appropriate varieties of voice flows.

  3. A probabilistic approach for fair-efficient call admission control in wireless multiservice networks

    NASA Astrophysics Data System (ADS)

    Stratogiannis, Dimitrios G.; Tsiropoulos, Georgios I.; Kanellopoulos, John D.; Cottis, Panayotis G.

    2010-12-01

    The efficiency of call admission control (CAC) schemes in multiclass wireless networks should be evaluated not only with regard to the call blocking probability (CBP) achieved for every service class (SC) supported but also with regard to quality of service (QoS) and network efficiency criteria. In this article, four CAC schemes offering priority to SCs of advanced QoS requirements, based on guard channel policy, are studied and evaluated taking into account fairness and throughput criteria in addition to CBP. For the performance evaluation of the proposed CAC schemes and to examine fairness issues, two fairness indices are introduced along with a throughput metric. The analytical results, validated through extensive simulations, indicate that by appropriate selection of the CAC parameters satisfactory fairness and throughput are achieved while achieving low CBP.

  4. Adaptive call admission control and resource allocation in multi server wireless/cellular network

    NASA Astrophysics Data System (ADS)

    Jain, Madhu; Mittal, Ragini

    2016-11-01

    The ever increasing demand of the subscribers has put pressure on the capacity of wireless networks around the world. To utilize the scare resources, in the present paper we propose an optimal allocation scheme for an integrated wireless/cellular model with handoff priority and handoff guarantee services. The suggested algorithm optimally allocates the resources in each cell and dynamically adjust threshold to control the admission. To give the priority to handoff calls over the new calls, the provision of guard channels and subrating scheme is taken into consideration. The handoff voice call may balk and renege from the system while waiting in the buffer. An iterative algorithm is implemented to generate the arrival rate of the handoff calls in each cell. Various performance indices are established in term of steady state probabilities. The sensitivity analysis has also been carried out to examine the tractability of algorithms and to explore the effects of system descriptors on the performance indices.

  5. Controlling the Front Gates: Effective Admissions Policies and Practices. Pathways to Juvenile Detention Reform 3.

    ERIC Educational Resources Information Center

    Orlando, Frank

    This report identifies policies and practices essential to overcoming problems with admissions to juvenile detention facilities, using information from the Juvenile Detention Alternatives Initiative (JDAI). Chapter 1, "Why Objective Admissions Policies and Practices Are Critical to Detention Reform," describes factors contributing to…

  6. Tethered satellite control mechanism

    NASA Technical Reports Server (NTRS)

    Kyrias, G. M.

    1983-01-01

    The tethered satellite control mechanisms consist of four major subsystems. The reel drive mechanism stores the tether. It is motor driven and includes a level wind to uniformly feed the tether to the reel. The lower boom mechanism serves two primary functions: (1) it measures tether length and velocity as the tether runs through the mechanism, and (2) it reads the tether tension at the reel. It also provides change the direction for the tether from the reel to the upper boom mechanism. The deployment boom positions the upper boom mechanism with satellite out of the cargo bay. The deployment function places the 500-kg satellite 20 m away from the Space Shuttle (producing a small natural gravity gradient force), impacts an initial velocity to the satellite for deployment, and allows for satellite docking at a safe distance from the body of the Space Shuttle. The upper boom mechanism (UBM) services three functions: (1) it provides tether control to the satellite as the satellite swings in and out of plane; (2) it reads tether tension in the low range during the early deployment and final retrieval parts of the mission; and (3) it produces additional tether tension at the reel when tether tension to the satellite is in the low range.

  7. Decentralized control of Markovian decision processes: Existence Sigma-admissable policies

    NASA Technical Reports Server (NTRS)

    Greenland, A.

    1980-01-01

    The problem of formulating and analyzing Markov decision models having decentralized information and decision patterns is examined. Included are basic examples as well as the mathematical preliminaries needed to understand Markov decision models and, further, to superimpose decentralized decision structures on them. The notion of a variance admissible policy for the model is introduced and it is proved that there exist (possibly nondeterministic) optional policies from the class of variance admissible policies. Directions for further research are explored.

  8. REACTOR CONTROL MECHANISM

    DOEpatents

    Lane, J.A.; Engberg, R.E.; Welch, J.M.

    1959-05-12

    A quick-releasing mechanism is described which may be used to rapidiy drop a device supported from beneath during normal use, such as a safety rod in a nuclear reactor. In accordance with this invention an electrical control signal, such as may be provided by radiation detection or other alarm condition sensing devices, is delivered to an electromagnetic solenoid, the armature of which is coupled to an actuating mechanism. The solenoid is energized when the mechanism is in its upper or cocked position. In such position, the mechanism engages a plurality of retaining balls, forcing them outward into engagement with a shoulder or recess in a corresponding section of a tubular extension on the upheld device. When the control signal to the solenoid suddenly ceases, the armature drops out, allowing the actuating mechanism to move slightly but rapidly under the force of a compressed spring. The weight of the device will urge the balls inward against a beveled portion of the actuating mechanism and away from the engaging section on the tubular extension, thus allowing the upheld device to fall freely under the influence of gravity.

  9. Parenteral penicillin for children with meningococcal disease before hospital admission: case-control study

    PubMed Central

    Harnden, Anthony; Ninis, Nelly; Thompson, Matthew; Perera, Rafael; Levin, Michael; Mant, David; Mayon-White, Richard

    2006-01-01

    Objective To explore the impact on mortality and morbidity of parenteral penicillin given to children before admission to hospital with suspected meningococcal disease. Design Retrospective comparison of fatal and non-fatal cases. Setting England, Wales, and Northern Ireland; December 1997 to February 1999. Participants 158 children aged 0-16 years (26 died, 132 survived) in whom a general practitioner had made the diagnosis of meningococcal disease before hospital admission. Results Administration of parenteral penicillin by general practitioners was associated with increased odds ratios for death (7.4, 95% confidence interval 1.5 to 37.7) and complications in survivors (5.0, 1.7 to 15.0). Children who received penicillin had more severe disease on admission (median Glasgow meningococcal septicaemia prognostic score (GMSPS) 6.5 v 4.0, P = 0.002). Severity on admission did not differ significantly with time taken to reach hospital. Conclusions Children who were given parenteral penicillin by a general practitioner had more severe disease on reaching hospital than those who were not given penicillin before admission. The association with poor outcome may be because children who are more severely ill are being given penicillin before admission. PMID:16554335

  10. Admission control and quality adaptation in the distributed multimedia server system (DMSS)

    NASA Astrophysics Data System (ADS)

    Akbar, Mohammad M.; Manning, Eric G.; Shoja, Gholamali C.

    2001-07-01

    Transmission of the real-time components, such as video and voice of multimedia streams over internets requires pre-allocation of network bandwidth from source to destination, as well as CPU cycles, I/O bandwidth, etc. in the server and in the client providing multimedia services. This paper presents a distributed version of the Utility Model for admission control and Quality of Service (QoS) adaptation of a multi server multimedia service provider. We propose a broker for managing the resources of the servers. This version of the Utility Model is quasi-distributed, meaning that computations for resource allocation are done at a single site (the broker), but the resources considered are distributed over multiple servers. This paper presents the architecture of the broker and the algorithm used by the broker to select the sessions, so that the QoS requirements are met while revenue is maximized. The QoS adaptation policy used to achieve fault tolerance during server failure is described.

  11. Admission Control Over Internet of Vehicles Attached With Medical Sensors for Ubiquitous Healthcare Applications.

    PubMed

    Lin, Di; Labeau, Fabrice; Yao, Yuanzhe; Vasilakos, Athanasios V; Tang, Yu

    2016-07-01

    Wireless technologies and vehicle-mounted or wearable medical sensors are pervasive to support ubiquitous healthcare applications. However, a critical issue of using wireless communications under a healthcare scenario rests at the electromagnetic interference (EMI) caused by radio frequency transmission. A high level of EMI may lead to a critical malfunction of medical sensors, and in such a scenario, a few users who are not transmitting emergency data could be required to reduce their transmit power or even temporarily disconnect from the network in order to guarantee the normal operation of medical sensors as well as the transmission of emergency data. In this paper, we propose a joint power and admission control algorithm to schedule the users' transmission of medical data. The objective of this algorithm is to minimize the number of users who are forced to disconnect from the network while keeping the EMI on medical sensors at an acceptable level. We show that a fixed point of proposed algorithm always exists, and at the fixed point, our proposed algorithm can minimize the number of low-priority users who are required to disconnect from the network. Numerical results illustrate that the proposed algorithm can achieve robust performance against the variations of mobile hospital environments.

  12. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications.

    PubMed

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e.

  13. Medical-Grade Channel Access and Admission Control in 802.11e EDCA for Healthcare Applications

    PubMed Central

    Son, Sunghwa; Park, Kyung-Joon; Park, Eun-Chan

    2016-01-01

    In this paper, we deal with the problem of assuring medical-grade quality of service (QoS) for real-time medical applications in wireless healthcare systems based on IEEE 802.11e. Firstly, we show that the differentiated channel access of IEEE 802.11e cannot effectively assure medical-grade QoS because of priority inversion. To resolve this problem, we propose an efficient channel access algorithm. The proposed algorithm adjusts arbitrary inter-frame space (AIFS) in the IEEE 802.11e protocol depending on the QoS measurement of medical traffic, to provide differentiated near-absolute priority for medical traffic. In addition, based on rigorous capacity analysis, we propose an admission control scheme that can avoid performance degradation due to network overload. Via extensive simulations, we show that the proposed mechanism strictly assures the medical-grade QoS and improves the throughput of low-priority traffic by more than several times compared to the conventional IEEE 802.11e. PMID:27490666

  14. Shocking Admission

    ERIC Educational Resources Information Center

    Hoover, Eric; Millman, Sierra

    2007-01-01

    Marilee Jones's career had been a remarkable success. She joined Massachusetts Institute of Technology's (MIT's) admissions office in 1979, landing a job in Cambridge at a time when boys ruled the sandbox of the admissions profession. Her job was to help MIT recruit more women, who then made up less than one-fifth of the institute's students. She…

  15. Use of a control chart to monitor diarrhoea admissions: a quality improvement exercise in West Kalimantan Provincial Hospital, Pontianak, Indonesia.

    PubMed

    Purba, M

    1999-09-01

    Data on the number of admissions for diarrhoea each week to the West Kalimantan Provincial Hospital, Pontianak, Indonesia over a 5 year period, 1992-1996, were collected. After cleaning and exclusion of extreme values, transformation was then performed to ensure that the data were free of special cause variation and normally distributed. A control chart was then constructed to provide an 'early warning' system for hospital authorities in order to facilitate the management of the epidemic and to improve patient care.

  16. Loneliness and nursing home admission among rural older adults.

    PubMed

    Russell, D W; Cutrona, C E; de la Mora, A; Wallace, R B

    1997-12-01

    In this study, the authors tested the relation between loneliness and subsequent admission to a nursing home over a 4-year time period in a sample of approximately 3,000 rural older Iowans. Higher levels of loneliness were found to increase the likelihood of nursing home admission and to decrease the time until nursing home admission. The influence of extremely high loneliness on nursing home admission remained statistically significant after controlling for other variables, such as age, education, income, mental status, physical health, morale, and social contact, that were also predictive of nursing home admission. Several mechanisms are proposed to explain the link between extreme loneliness and nursing home admission. These include loneliness as a precipitant of declines in mental and physical health and nursing home placement as a strategy to gain social contact with others. Implications for preventative interventions are discussed.

  17. Pharmacist provided medicines reconciliation within 24 hours of admission and on discharge: a randomised controlled pilot study

    PubMed Central

    Cadman, Brit; Wright, David; Bale, Amanda; Barton, Garry; Desborough, James; Hammad, Eman A; Holland, Richard; Howe, Helen; Nunney, Ian; Irvine, Lisa

    2017-01-01

    Background The UK government currently recommends that all patients receive medicines reconciliation (MR) from a member of the pharmacy team within 24 hours of admission and subsequent discharge. The cost-effectiveness of this intervention is unknown. A pilot study to inform the design of a future randomised controlled trial to determine effectiveness and cost-effectiveness of a pharmacist-delivered service was undertaken. Method Patients were recruited 7 days a week from 5 adult medical wards in 1 hospital over a 9 month period and randomised using an automated system to intervention (MR within 24 hours of admission and at discharge) or usual care which may include MR (control). Recruitment and retention rates were determined. Length of stay (LOS), quality of life (EQ-5D-3L), unintentional discrepancies (UDs) and emergency readmission (ER) within 3 months were tested as outcome measures. The feasibility of identifying and measuring intervention-associated resources was determined. Result 200 patients were randomised to either intervention or control. Groups were comparable at baseline. 95 (99%) patients in the intervention received MR within 24 hours, while 62 (60.8%) control patients received MR at some point during admission. The intervention resolved 250 of the 255 UDs identified at admission. Only 2 UDs were identified in the intervention group at discharge compared with 268 in the control. The median LOS was 94 hours in the intervention arm and 118 hours in the control, with ER rates of 17.9% and 26.7%, respectively. Assuming 5% loss to follow-up 1120 patients (560 in each arm) are required to detect a 6% reduction in 3-month ER rates. Conclusions The results suggest that changes in outcome measures resulting from MR within 24 hours were in the appropriate direction and readmission within 3 months is the most appropriate primary outcome measure. A future study to determine cost-effectiveness of the intervention is feasible and warranted

  18. Gear shift control mechanism

    SciTech Connect

    Janson, D.A.

    1987-03-10

    A gear shift control mechanism is described comprising: multiple shift rods directed substantially parallel to one another, each rod carrying a shift fork for axial movement; a shift lever supported for pivotal movement about a first axis directed parallel to the axes of the shift rods and for pivotal movement about a second axis directed substantially perpendicular to the axes of the shift rods. The lever is moveable about the first axis and the second axis into engagement with a selected shift fork; interlock means located on each lateral side of the shift lever and mounted for pivotal movement about the first axis for blocking engagement with the shift forks; detent means for holding the shift lever in multiple predetermined angular positions about the second axis; and spring means located on a lateral side of the shift lever and mounted for pivotal movement about the first axis into interference contact with the shift forks for producing a force tending to resiliently bias the shift lever out of engagement with the selected shift fork.

  19. A new LP formulation of the admission control problem modelled as an MDP under average reward criterion

    NASA Astrophysics Data System (ADS)

    Pietrabissa, Antonio

    2011-12-01

    The admission control problem can be modelled as a Markov decision process (MDP) under the average cost criterion and formulated as a linear programming (LP) problem. The LP formulation is attractive in the present and future communication networks, which support an increasing number of classes of service, since it can be used to explicitly control class-level requirements, such as class blocking probabilities. On the other hand, the LP formulation suffers from scalability problems as the number C of classes increases. This article proposes a new LP formulation, which, even if it does not introduce any approximation, is much more scalable: the problem size reduction with respect to the standard LP formulation is O((C + 1)2/2 C ). Theoretical and numerical simulation results prove the effectiveness of the proposed approach.

  20. Controlled mechanized trepan.

    PubMed

    Kam, J; Goldratt, E M; Barishak, Y R; Stein, R

    1978-04-01

    A mechanized trepan is described whose cutting action is halted automatically when the trepan's cutting edge reaches the last 0.03 mm. tissue layer of the cornea. The automatic half of both the motor which advances the trepan as well as the second motor which rotates the trepan is triggered by the sudden change in electrical resistance between the trepan and the patient's internal body fluid, at the final stage of penetration. This automatic feature eliminates the danger of inadvertant damage to the inner structures of the eye.

  1. Association between Birth Order and Emergency Room Visits and Acute Hospital Admissions following Pediatric Vaccination: A Self-Controlled Study

    PubMed Central

    Hawken, Steven; Kwong, Jeffrey C.; Deeks, Shelley L.; Crowcroft, Natasha S.; Ducharme, Robin; Manuel, Douglas G.; Wilson, Kumanan

    2013-01-01

    Objective We investigated the association between a child's birth order and emergency room (ER) visits and hospital admissions following 2-,4-,6- and 12-month pediatric vaccinations. Methods We included all children born in Ontario between April 1st, 2006 and March 31st, 2009 who received a qualifying vaccination. We identified vaccinations, ER visits and admissions using health administrative data housed at the Institute for Clinical Evaluative Sciences. We used the self-controlled case series design to compare the relative incidence (RI) of events among 1st-born and later-born children using relative incidence ratios (RIR). Results For the 2-month vaccination, the RIR for 1st-borns versus later-born children was 1.37 (95% CI: 1.19–1.57), which translates to 112 additional events/100,000 vaccinated. For the 4-month vaccination, the RIR for 1st-borns vs. later-borns was 1.70 (95% CI: 1.45–1.99), representing 157 additional events/100,000 vaccinated. At 6 months, the RIR for 1st vs. later-borns was 1.27 (95% CI: 1.09–1.48), or 77 excess events/100,000 vaccinated. At the 12-month vaccination, the RIR was 1.11 (95% CI: 1.02–1.21), or 249 excess events/100,000 vaccinated. Conclusions Birth order is associated with increased incidence of ER visits and hospitalizations following vaccination in infancy. 1st-born children had significantly higher relative incidence of events compared to later-born children. PMID:24324662

  2. Brain Mechanisms of Attentional Control.

    ERIC Educational Resources Information Center

    Wilke, Thomas

    Lack of attentional control--inability to concentrate--has often made the difference between successful and unsuccessful performance on the part of athletes. Attention is controlled neurologically by a very complex interaction of a large portion of the cerebrum and is not localized to any one structure. The mechanism involves a memory retrieval…

  3. Relationships among Reading Performance, Locus of Control and Achievement for Marginal Admission Students.

    ERIC Educational Resources Information Center

    Pepper, Roger S.; Drexler, John A., Jr.

    The first phase of the study was a 2 x 2 factorial design, with locus of control and instructional method (lecture and demonstration) as independent variables and honor point average (HPA) as the dependent variable. The second phase used correlational techniques to test the extent to which reading performance and traditional predictors of…

  4. Control Processes and Defense Mechanisms

    PubMed Central

    HOROWITZ, MARDI; COOPER, STEVEN; FRIDHANDLER, BRAM; PERRY, J. CHRISTOPHER; BOND, MICHAEL; VAILLANT, GEORGE

    1992-01-01

    Defense-mechanism theory and control-process theory are related psychodynamic approaches to explaining and classifying how people ward off emotional upsets. Although both theories explain defensive maneuvers in the same motivational terms, each defines categories different1y. Classic categories define defense mechanisms at a relatively macroscopic level, whereas control-process theory aims at relatively microgenetic analysis of how cognitive maneuvers—involving what is thought, how it is thought, and how it is organized—may generate defensive states. The theories are not contradictory, but they are focused on different levels of observation; it is useful to compare how these classifications are applied to specific case material. PMID:22700114

  5. Dynamic Multiple-Threshold Call Admission Control Based on Optimized Genetic Algorithm in Wireless/Mobile Networks

    NASA Astrophysics Data System (ADS)

    Wang, Shengling; Cui, Yong; Koodli, Rajeev; Hou, Yibin; Huang, Zhangqin

    Due to the dynamics of topology and resources, Call Admission Control (CAC) plays a significant role for increasing resource utilization ratio and guaranteeing users' QoS requirements in wireless/mobile networks. In this paper, a dynamic multi-threshold CAC scheme is proposed to serve multi-class service in a wireless/mobile network. The thresholds are renewed at the beginning of each time interval to react to the changing mobility rate and network load. To find suitable thresholds, a reward-penalty model is designed, which provides different priorities between different service classes and call types through different reward/penalty policies according to network load and average call arrival rate. To speed up the running time of CAC, an Optimized Genetic Algorithm (OGA) is presented, whose components such as encoding, population initialization, fitness function and mutation etc., are all optimized in terms of the traits of the CAC problem. The simulation demonstrates that the proposed CAC scheme outperforms the similar schemes, which means the optimization is realized. Finally, the simulation shows the efficiency of OGA.

  6. Universal Controller for Spacecraft Mechanisms

    NASA Technical Reports Server (NTRS)

    Levanas, Greg; McCarthy, Thomas; Hunter, Don; Buchanan, Christine; Johnson, Michael; Cozy, Raymond; Morgan, Albert; Tran, Hung

    2006-01-01

    An electronic control unit has been fabricated and tested that can be replicated as a universal interface between the electronic infrastructure of a spacecraft and a brushless-motor (or other electromechanical actuator) driven mechanism that performs a specific mechanical function within the overall spacecraft system. The unit includes interfaces to a variety of spacecraft sensors, power outputs, and has selectable actuator control parameters making the assembly a mechanism controller. Several control topologies are selectable and reconfigurable at any time. This allows the same actuator to perform different functions during the mission life of the spacecraft. The unit includes complementary metal oxide/semiconductor electronic components on a circuit board of a type called rigid flex (signifying flexible printed wiring along with a rigid substrate). The rigid flex board is folded to make the unit fit into a housing on the back of a motor. The assembly has redundant critical interfaces, allowing the controller to perform time-critical operations when no human interface with the hardware is possible. The controller is designed to function over a wide temperature range without the need for thermal control, including withstanding significant thermal cycling, making it usable in nearly all environments that spacecraft or landers will endure. A prototype has withstood 1,500 thermal cycles between 120 and +85 C without significant deterioration of its packaging or electronic function. Because there is no need for thermal control and the unit is addressed through a serial bus interface, the cabling and other system hardware are substantially reduced in quantity and complexity, with corresponding reductions in overall spacecraft mass and cost.

  7. Mechanical control of electroresistive switching

    SciTech Connect

    Kim, Yunseok; Kelly, Simon J; Strelcov, Evgheni; Jesse, Stephen; Biegalski, Michael D; Balke, Nina; Maksymovych, Petro; Kalinin, Sergei V

    2013-01-01

    Hysteretic metal-insulator transitions (MIT) mediated by ionic dynamics or ferroic phase transitions underpin emergent applications for non-volatile memories and logic devices. The vast majority of applications and studies have explored the MIT coupled to the electric field or temperarture. Here, we argue that MIT coupled to ionic dynamics should allow control by mechanical stimuli, the behavior we refer to as piezochemical effect. We verify this effect experimentally, and demonstrate that it allows both studying materials physics and enabling novel data storage technologies with mechanical writing and current based read-out.

  8. Turbomachinery Fluid Mechanics and Control

    DTIC Science & Technology

    2010-01-01

    side, thereby limiting the achievable flow. Further numerical studies were completed to improve the flow field performance in the internal passages...Shear Layers”, Journal of Fluid Mechanics , 1996, 308: 63-96 7. M. R. Van der Veer and P. J. Strykowski, “Counterflow Thrust Vector Control of...particularly for highly loaded blade rows, can be very complex and requires systematic study . In the work described here, experimental

  9. Immune mechanisms of HIV control

    PubMed Central

    Chakrabarti, Lisa A.; Simon, Viviana

    2010-01-01

    Summary HIV-1 can be contained by the immune system, as demonstrated by the existence of rare individuals who spontaneously control HIV-1 replication in the absence of antiretroviral therapy. Emerging evidence points to the importance of a very active cellular immune response in mediating HIV-1 control. The rapid induction of interferon-dependent HIV restriction factors, the presence of protective MHC class I alleles, and the development of a high avidity T-cell response may all cooperate in limiting HIV replication at an early stage. This review will focus on recent advances in understanding the immune mechanisms of HIV control, and on the lessons that may be drawn for the development of candidate HIV vaccines. PMID:20650621

  10. Post Admission Cognitive Therapy (PACT) for the Inpatient Treatment of Military Personnel with Suicidal Behaviors: A Multi-Site Randomized Controlled Trial

    DTIC Science & Technology

    2013-02-01

    depression, trauma, sleep , suicide ideation), repeat number of psychiatric hospitalization(s), hope for one’s future, and acceptability of treatment (as...0106 TITLE: Post Admission Cognitive Therapy (PACT) for the Inpatient Treatment of Military Personnel with Suicidal Behaviors: A Multi- Site...Inpatient Treatment of Military Personnel with Suicidal Behaviors: A Multi-Site Randomized Controlled Trial Service Members and Veterans 5a

  11. Effectiveness of telemonitoring integrated into existing clinical services on hospital admission for exacerbation of chronic obstructive pulmonary disease: researcher blind, multicentre, randomised controlled trial

    PubMed Central

    Hanley, Janet; McCloughan, Lucy; Todd, Allison; Krishan, Ashma; Lewis, Stephanie; Stoddart, Andrew; van der Pol, Marjon; MacNee, William; Sheikh, Aziz; Pagliari, Claudia; McKinstry, Brian

    2013-01-01

    Objective To test the effectiveness of telemonitoring integrated into existing clinical services such that intervention and control groups have access to the same clinical care. Design Researcher blind, multicentre, randomised controlled trial. Setting UK primary care (Lothian, Scotland). Participants Adults with at least one admission for chronic obstructive pulmonary disease (COPD) in the year before randomisation. We excluded people who had other significant lung disease, who were unable to provide informed consent or complete the study, or who had other significant social or clinical problems. Interventions Participants were recruited between 21 May 2009 and 28 March 2011, and centrally randomised to receive telemonitoring or conventional self monitoring. Using a touch screen, telemonitoring participants recorded a daily questionnaire about symptoms and treatment use, and monitored oxygen saturation using linked instruments. Algorithms, based on the symptom score, generated alerts if readings were omitted or breached thresholds. Both groups received similar care from existing clinical services. Main outcome measures The primary outcome was time to hospital admission due to COPD exacerbation up to one year after randomisation. Other outcomes included number and duration of admissions, and validated questionnaire assessments of health related quality of life (using St George’s respiratory questionnaire (SGRQ)), anxiety or depression (or both), self efficacy, knowledge, and adherence to treatment. Analysis was intention to treat. Results Of 256 patients completing the study, 128 patients were randomised to telemonitoring and 128 to usual care; baseline characteristics of each group were similar. The number of days to admission did not differ significantly between groups (adjusted hazard ratio 0.98, 95% confidence interval 0.66 to 1.44). Over one year, the mean number of COPD admissions was similar in both groups (telemonitoring 1.2 admissions per person

  12. Reduction in hospital admissions for pneumonia in non-institutionalised elderly people as a result of influenza vaccination: a case-control study in Spain.

    PubMed Central

    Puig-Barberà, J; Márquez-Calderón, S; Masoliver-Fores, A; Lloria-Paes, F; Ortega-Dicha, A; Gil-Martín, M; Calero-Martínez, M J

    1997-01-01

    OBJECTIVE: To estimate the effectiveness of influenza vaccine in preventing hospital admission for pneumonia in non-institutionalised elderly people. DESIGN: This was a case-control study. SETTING: All three public hospitals in the Castellón area of Spain. PARTICIPANTS: Cases were people aged 65 or more not living in an institution who were admitted to hospital for pneumonia between November 15, 1994 and March 31, 1995. Each case was matched with two sex matched control subjects aged 65 years or older admitted to hospital in the same week for acute abdominal surgical conditions or trauma. The sampling of incident cases was consecutive. Eighty three cases and 166 controls were identified and included in the study. MEASUREMENTS: Trained interviewers completed a questionnaire for each subject on the vaccination status, smoking habits, previous diseases, health care use, social contacts, family background, the vaccination status of the family carer, home characteristics, and socioeconomic status. RESULTS: The adjusted odds ratio of the influenza vaccination preventing admission to hospital for pneumonia was 0.21 (95% confidence interval 0.09, 0.55). The variables which best explained the risk of being a case were age, intensity of social contacts, health care use, previous diseases, and the existence of a vaccinated family carer. CONCLUSIONS: Influenza vaccination reduced significantly hospital admissions for pneumonia in non-institutionalised elderly people. PMID:9425463

  13. Autoregulatory mechanisms controlling the Microprocessor.

    PubMed

    Triboulet, Robinson; Gregory, Richard I

    2010-01-01

    The Microprocessor, comprising the ribonuclease Drosha and its essential cofactor, the double-stranded RNA-binding protein, DGCR8, is essential for the first step of the miRNA biogenesis pathway. It specifically cleaves double-stranded RNA within stem-loop structures of primary miRNA transcripts (pri-miRNAs) to generate precursor (pre-miRNA) intermediates. Pre-miRNAs are subsequently processed by Dicer to their mature 22 nt form. Thus, Microprocessor is essential for miRNA maturation, and pri-miRNA cleavage by this complex defines one end of the mature miRNA. Moreover, it is emerging that dysregulation of the Microprocessor is associated with various human diseases. It is therefore important to understand the mechanisms by which the expression of the subunits of the Microprocessor is regulated. Recent findings have uncovered a post-transcriptional mechanism that maintains the integrity of the Microprocessor. These studies revealed that the Microprocessor is involved in the processing of the messenger RNA (mRNA) that encodes DGCR8. This regulatory feedback loop, along with the reported role played by DGCR8 in the stabilization of Drosha protein, is part ofa newly identified regulatory mechanism controlling Microprocessor activity.

  14. Autoregulatory mechanisms controlling the microprocessor.

    PubMed

    Triboulet, Robinson; Gregory, Richard I

    2011-01-01

    The Microprocessor, comprising the ribonuclease Drosha and its essential cofactor, the double-stranded RNA-binding protein, DGCR8, is essential for the first step of the miRNA biogenesis pathway. It specifically cleaves double-stranded RNA within stem-loop structures of primary miRNA transcripts (pri-miRNAs) to generate precursor (pre-miRNA) intermediates. Pre-miRNAs are subsequently processed by Dicer to their mature ∼22 nt form. Thus, Microprocessor is essential for miRNA maturation, and pri-miRNA cleavage by this complex defines one end of the mature miRNA. Moreover, it is emerging that dysregulation of the Microprocessor is associated with various human diseases. It is therefore important to understand the mechanisms by which the expression of the subunits of the Microprocessor is regulated. Recent findings have uncovered a post-transcriptional mechanism that maintains the integrity of the Microprocessor. These studies revealed that the Microprocessor is involved in the processing of the messenger RNA (mRNA) that encodes DGCR8. This regulatory feedback loop, along with the reported role played by DGCR8 in the stabilization of Drosha protein, is part of a newly identified regulatory mechanism controlling Microprocessor activity.

  15. School Admissions Reform in Chicago and England: Comparing Mechanisms by Their Vulnerability to Manipulation. NBER Working Paper No. 16783

    ERIC Educational Resources Information Center

    Pathak, Parag A.; Sonmez, Tayfun

    2011-01-01

    In Fall 2009, officials from Chicago Public Schools changed their assignment mechanism for coveted spots at selective college preparatory high schools midstream. After asking about 14,000 applicants to submit their preferences for schools under one mechanism, the district asked them re-submit their preferences under a new mechanism. Officials were…

  16. Seeking the Admission Hybrid

    ERIC Educational Resources Information Center

    Lucido, Jerome A.

    2012-01-01

    When one thinks of seminal publications in college admission, the first piece that comes to mind is B. Alden Thresher's "College Admissions in the Public Interest" (1966). Thresher's work, relevant to this day, is credited with being the foundational document of the admission profession. McDonough and Robertson's 1995 study, commissioned by NACAC,…

  17. Tuneable Auxiliary Control Mechanisms For RUM Actuators

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.; Alhorn, Dean C.

    1995-01-01

    Tuneable auxiliary control mechanisms for rotating unbalanced-mass (RUM) actuators used to maximize scan amplitudes and/or minimize power consumption during changing conditions. This type of mechanism more sophisticated version of type of mechanism described in "Auxiliary Control Mechanisms for RUM Actuators" (MFS-28817). Torsional stiffness of torsionally flexible coupling made adjustable on command. Torsionally flexible coupling in tuneable version of auxiliary control mechanism adjustable by use of stepping-motor-driven worm-gear mechanism that varies bending length of flexible blade.

  18. Effectiveness of rotavirus vaccination in prevention of hospital admissions for rotavirus gastroenteritis among young children in Belgium: case-control study

    PubMed Central

    Braeckman, Tessa; Van Herck, Koen; Meyer, Nadia; Pirçon, Jean-Yves; Soriano-Gabarró, Montse; Heylen, Elisabeth; Zeller, Mark; Azou, Myriam; Capiau, Heidi; De Koster, Jan; Maernoudt, Anne-Sophie; Raes, Marc; Verdonck, Lutgard; Verghote, Marc; Vergison, Anne; Matthijnssens, Jelle; Van Ranst, Marc

    2012-01-01

    Objective To evaluate the effectiveness of rotavirus vaccination among young children in Belgium. Design Prospective case-control study. Setting Random sample of 39 Belgian hospitals, February 2008 to June 2010. Participants 215 children admitted to hospital with rotavirus gastroenteritis confirmed by polymerase chain reaction and 276 age and hospital matched controls. All children were of an eligible age to have received rotavirus vaccination (that is, born after 1 October 2006 and aged ≥14 weeks). Main outcome measure Vaccination status of children admitted to hospital with rotavirus gastroenteritis and matched controls. Results 99 children (48%) admitted with rotavirus gastroenteritis and 244 (91%) controls had received at least one dose of any rotavirus vaccine (P<0.001). The monovalent rotavirus vaccine accounted for 92% (n=594) of all rotavirus vaccine doses. With hospital admission as the outcome, the unadjusted effectiveness of two doses of the monovalent rotavirus vaccine was 90% (95% confidence interval 81% to 95%) overall, 91% (75% to 97%) in children aged 3-11 months, and 90% (76% to 96%) in those aged ≥12 months. The G2P[4] genotype accounted for 52% of cases confirmed by polymerase chain reaction with eligible matched controls. Vaccine effectiveness was 85% (64% to 94%) against G2P[4] and 95% (78% to 99%) against G1P[8]. In 25% of cases confirmed by polymerase chain reaction with eligible matched controls, there was reported co-infection with adenovirus, astrovirus and/or norovirus. Vaccine effectiveness against co-infected cases was 86% (52% to 96%). Effectiveness of at least one dose of any rotavirus vaccine (intention to vaccinate analysis) was 91% (82% to 95%). Conclusions Rotavirus vaccination is effective for the prevention of admission to hospital for rotavirus gastroenteritis among young children in Belgium, despite the high prevalence of G2P[4] and viral co-infection. PMID:22875947

  19. Cooling Mechanical Oscillators by Coherent Control

    NASA Astrophysics Data System (ADS)

    Frimmer, Martin; Gieseler, Jan; Novotny, Lukas

    2016-10-01

    In optomechanics, electromagnetic fields are harnessed to control a single mode of a mechanically compliant system, while other mechanical degrees of freedom remain unaffected due to the modes' mutual orthogonality and high quality factor. Extension of the optical control beyond the directly addressed mode would require a controlled coupling between mechanical modes. Here, we introduce an optically controlled coupling between two oscillation modes of an optically levitated nanoparticle. We sympathetically cool one oscillation mode by coupling it coherently to the second mode, which is feedback cooled. Furthermore, we demonstrate coherent energy transfer between mechanical modes and discuss its application for ground-state cooling.

  20. What Admissions Officials Think

    ERIC Educational Resources Information Center

    Hoover, Eric

    2008-01-01

    Over the past two decades, college admissions has become a prime-time preoccupation. Most people know at least something about the process, especially if they have a teenager in high school and a college guide on their coffee table. Nonetheless, widespread public misconceptions persist about admissions requirements, the selection process, and the…

  1. The Administration of Admissions

    ERIC Educational Resources Information Center

    Campbell, Clifford C.

    1978-01-01

    Among all the tasks of the admissions officer in developing a successful marketing program, the hardest may be that of convincing other college administrators of the importance of admissions to the institution's survival. Discussed are long-range planning, budgeting, staff selection and training, and implementing a plan. (Author/LBH)

  2. Technology in International Admissions

    ERIC Educational Resources Information Center

    White, Elizabeth

    2012-01-01

    In a relatively short time, technology applications have become an essential feature of the admissions business. They make the jobs of international admissions professionals easier in many ways, allowing for more robust communication with applicants and counselors, a streamlined application process, and quicker access to information about…

  3. Mechanically controlled radical polymerization initiated by ultrasound

    NASA Astrophysics Data System (ADS)

    Mohapatra, Hemakesh; Kleiman, Maya; Esser-Kahn, Aaron Palmer

    2016-10-01

    In polymer chemistry, mechanical energy degrades polymeric chains. In contrast, in nature, mechanical energy is often used to create new polymers. This mechanically stimulated growth is a key component of the robustness of biological materials. A synthetic system in which mechanical force initiates polymerization will provide similar robustness in polymeric materials. Here we show a polymerization of acrylate monomers initiated and controlled by mechanical energy provided by ultrasonic agitation. The activator for an atom-transfer radical polymerization is generated using piezochemical reduction of a Cu(II) precursor complex, which thus converts a mechanical activation of piezoelectric particles to the synthesis of a new material. This polymerization reaction has some characteristics of controlled radical polymerization, such as narrow molecular-weight distribution and linear dependence of the polymeric chain length on the time of mechanical activation. This new method of controlled radical polymerization complements the existing methods to synthesize commercially useful well-defined polymers.

  4. Effect of pharmaceutical care on medication adherence and hospital admission in patients with chronic obstructive pulmonary disease (COPD): a randomized controlled study

    PubMed Central

    Wei, Li; Yang, Xinyun; Li, Jie; Liu, Lianghui; Luo, Hongying; Zheng, Zeguang

    2014-01-01

    Background Poor adherence leads to a high rate of exacerbation and poor health-related quality of life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD). However, few strategies are acceptable and effective in improving medication adherence. We investigated whether pharmaceutical care by clinical pharmacists could reinforce medication adherence to reduce exacerbation and improve HRQoL. Methods A randomized controlled study was carried out at The First Affiliated Hospital of Guangzhou Medical University from February 2012 to January 2014. Non-adherence patients were randomly assigned to receive pharmaceutical care or to usual care. The pharmaceutical care consisted of individualized education and a series of telephone counseling for 6 months provided by clinical pharmacists. Medication adherence was measured by pill counts plus direct interview at 1- and 6-month pharmaceutical care and one-year follow-up. Severe exacerbations were defined as events that led to hospitalization for acute COPD attack. An interview was conducted to investigate hospital admissions and evaluate severe exacerbations at one-year follow-up. HRQoL was measured by St George’s Respiratory Questionnaire at 6 months. Results At 6-month pharmaceutical care and one-year follow-up, the pharmaceutical care group exhibited higher medication adherence than the usual care group (73.4±11.1 vs. 55.7±11.9, P=0.016 and 54.4±12.5 vs. 66.5±8.6, P=0.039, respectively). There are 60 acute exacerbations resulted in a hospital admission in the usual group while 37 ones in the pharmaceutical care group during one-year follow-up (P=0.01). Hospital admissions due to acute exacerbation in the pharmaceutical care group were 56.3% less than the usual care group (P=0.01). There was a significant difference in the symptoms and impact subscales respectively at 6-month pharmaceutical care between two groups (P=0.032, P=0.018). Conclusions Individualized pharmaceutical care improved medication

  5. Comparison of CATs, CURB-65 and PMEWS as Triage Tools in Pandemic Influenza Admissions to UK Hospitals: Case Control Analysis Using Retrospective Data

    PubMed Central

    Myles, Puja R.; Nguyen-Van-Tam, Jonathan S.; Lim, Wei Shen; Nicholson, Karl G.; Brett, Stephen J.; Enstone, Joanne E.; McMenamin, James; Openshaw, Peter J. M.; Read, Robert C.; Taylor, Bruce L.; Bannister, Barbara; Semple, Malcolm G.

    2012-01-01

    Triage tools have an important role in pandemics to identify those most likely to benefit from higher levels of care. We compared Community Assessment Tools (CATs), the CURB-65 score, and the Pandemic Medical Early Warning Score (PMEWS); to predict higher levels of care (high dependency - Level 2 or intensive care - Level 3) and/or death in patients at or shortly after admission to hospital with A/H1N1 2009 pandemic influenza. This was a case-control analysis using retrospectively collected data from the FLU-CIN cohort (1040 adults, 480 children) with PCR-confirmed A/H1N1 2009 influenza. Area under receiver operator curves (AUROC), sensitivity, specificity, positive predictive values and negative predictive values were calculated. CATs best predicted Level 2/3 admissions in both adults [AUROC (95% CI): CATs 0.77 (0.73, 0.80); CURB-65 0.68 (0.64, 0.72); PMEWS 0.68 (0.64, 0.73), p<0.001] and children [AUROC: CATs 0.74 (0.68, 0.80); CURB-65 0.52 (0.46, 0.59); PMEWS 0.69 (0.62, 0.75), p<0.001]. CURB-65 and CATs were similar in predicting death in adults with both performing better than PMEWS; and CATs best predicted death in children. CATs were the best predictor of Level 2/3 care and/or death for both adults and children. CATs are potentially useful triage tools for predicting need for higher levels of care and/or mortality in patients of all ages. PMID:22509303

  6. Student Admission and Attendance.

    ERIC Educational Resources Information Center

    Majestic, Ann L.

    1988-01-01

    Considers the North Carolina statutes that define the process for admitting students to public schools and ensuring their attendance. Examines cases relating to issues of school admission and compulsory attendance. (MLF)

  7. Hospice Admission Assessment.

    PubMed

    Moon, Paul J

    2017-04-01

    Hospice admission assessment is a pivotal encounter for patient/family and hospice representative. For patient/family, the admission is the threshold by which a particular level of care can commence and, symbolically, a certain marker in health status trajectory is reached. For hospice representative, the admission episode is an occasion to inaugurate an ambience that can serve to frame future hospice care experiences for the patient/family. Through a narrative lens, hospice admission assessment can be seen as experiential time and space, where patient's and family's stories are mindfully and deliberately witnessed and explored. Through the practice of narrative mining, the hospice representative can better understand others' offered stories of reality, which will better inform the plan of palliation and hospice care.

  8. Post Admission Cognitive Therapy (PACT) for the Inpatient Treatment of Military Personnel with Suicidal Behaviors: A Multi-Site Randomized Controlled Trial

    DTIC Science & Technology

    2012-02-01

    proposal addresses this important gap and aims to evaluate an innovative suicide intervention , Post Admission Cognitive Therapy (PACT). Left...cognitive behavioral intervention program, titled, Post Admission Cognitive Therapy (PACT), for military service members and beneficiaries admitted...listening to digital recordings of therapy sessions and/or reviewing of typed transcribed sessions for the purposes of treatment refinement and integrity

  9. Mechanics and aerodynamics of insect flight control.

    PubMed

    Taylor, G K

    2001-11-01

    Insects have evolved sophisticated fight control mechanisms permitting a remarkable range of manoeuvres. Here, I present a qualitative analysis of insect flight control from the perspective of flight mechanics, drawing upon both the neurophysiology and biomechanics literatures. The current literature does not permit a formal, quantitative analysis of flight control, because the aerodynamic force systems that biologists have measured have rarely been complete and the position of the centre of gravity has only been recorded in a few studies. Treating the two best-known insect orders (Diptera and Orthoptera) separately from other insects, I discuss the control mechanisms of different insects in detail. Recent experimental studies suggest that the helicopter model of flight control proposed for Drosophila spp. may be better thought of as a facultative strategy for flight control, rather than the fixed (albeit selected) constraint that it is usually interpreted to be. On the other hand, the so-called 'constant-lift reaction' of locusts appears not to be a reflex for maintaining constant lift at varying angles of attack, as is usually assumed, but rather a mechanism to restore the insect to pitch equilibrium following a disturbance. Differences in the kinematic control mechanisms used by the various insect orders are related to differences in the arrangement of the wings, the construction of the flight motor and the unsteady mechanisms of lift production that are used. Since the evolution of insect flight control is likely to have paralleled the evolutionary refinement of these unsteady aerodynamic mechanisms, taxonomic differences in the kinematics of control could provide an assay of the relative importance of different unsteady mechanisms. Although the control kinematics vary widely between orders, the number of degrees of freedom that different insects can control will always be limited by the number of independent control inputs that they use. Control of the moments

  10. Age Related Decline in Postural Control Mechanisms.

    ERIC Educational Resources Information Center

    Stelmach, George E.; And Others

    1989-01-01

    Studied voluntary and reflexive mechanisms of postural control of young (N=8) and elderly (N=8) adults through measurement of reflexive reactions to large-fast and small-slow ankle rotation postural disturbances. Found reflexive mechanisms relatively intact for both groups although elderly appeared more disadvantaged when posture was under the…

  11. Noise control mechanisms of inside aircraft

    NASA Astrophysics Data System (ADS)

    Zverev, A. Ya.

    2016-07-01

    World trends in the development of methods and approaches to noise reduction in aircraft cabins are reviewed. The paper discusses the mechanisms of passive and active noise and vibration control, application of "smart" and innovative materials, new approaches to creating all fuselage-design elements, and other promising directions of noise control inside aircraft.

  12. Damper mechanism for nuclear reactor control elements

    DOEpatents

    Taft, William Elwood

    1976-01-01

    A damper mechanism which provides a nuclear reactor control element decelerating function at the end of the scram stroke. The total damping function is produced by the combination of two assemblies, which operate in sequence. First, a tapered dashram assembly decelerates the control element to a lower velocity, after which a spring hydraulic damper assembly takes over to complete the final damping.

  13. Electric motor as the controlled mechanical transmission

    NASA Astrophysics Data System (ADS)

    Kukielka, Krzysztof

    2006-03-01

    The paper shows the possibility of using a brushless torque motor as controlled mechanical transmission. A development system for testing the torque motors was described and role of each component was discussed. Measured and observed phenomena of the research has shown the possibility of control the output rotations, preserving torque with simultaneous power consumption or its recovery, dependent on demanded transmission parameters.

  14. Logical Access Control Mechanisms in Computer Systems.

    ERIC Educational Resources Information Center

    Hsiao, David K.

    The subject of access control mechanisms in computer systems is concerned with effective means to protect the anonymity of private information on the one hand, and to regulate the access to shareable information on the other hand. Effective means for access control may be considered on three levels: memory, process and logical. This report is a…

  15. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  16. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  17. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  18. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  19. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  20. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  1. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  2. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  3. 14 CFR 27.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  4. 14 CFR 29.691 - Autorotation control mechanism.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Control Systems § 29.691 Autorotation control mechanism. Each main rotor blade pitch control mechanism must allow...

  5. [Nitrogen metabolism and its control mechanisms].

    PubMed

    Bergner, H

    1989-01-01

    N intake in the form of protein has neither got an upper nor a lower limit for agricultural working animals within a diet and there is no control mechanism for it. A high surplus of certain amino acids results in a reduction of feed intake. N excretion in faeces depends on 1) the excretion of N containing indigestible feedstuffs, 2) bacterial nitrogen synthesis in the large intestine and 3) the excretion of true endogenous N containing substances (digestion enzymes, intestinal epithelium, N containing endogenous secretion). There are no other control mechanisms for N excretion in faeces. N excretion in urine mainly comprises the nitrogen from the degeneration of amino acids and nucleic acids. The interrelations between urea, NH3, allantoin, creatine and creatinine, uric acid and hippuric acid depend on the species (monogastric or ruminants), on the nitrogen and N amount consumed and on the recycling ratio of the amino acids. The absolute amount of N excretion is not subject to any control mechanism, it depends on the intake of protein and NPN substances, the interim stages, however, which lead to the formation of excretory products, are intermediately controlled. The most important interim stage is protein biosynthesis, which is a fixed, intermediately controlled value in maintenance level. Under growth conditions only, the protein synthesis quota can exceed the protein degradation quota of the total organism (positive N balance). The control mechanisms of protein biosynthesis have, according to current knowledge, the following structure: Stimulation: 1) growth hormone (STH) stimulates protein synthesis by means of somatomedins; 2) hormones of the thyroid gland (T4 and T3) are controlled by the hormone stimulating the thyroid gland (TSH); 3) insulin. Inhibition: 1) somatostatin inhibits STH, TSH and insulin; 2) cortisol directly inhibits protein synthesis and stimulates protein degradation. The control mechanisms of protein turnover in addition to genetic coding

  6. Remote controlled vacuum joint closure mechanism

    DOEpatents

    Doll, David W.; Hager, E. Randolph

    1986-01-01

    A remotely operable and maintainable vacuum joint closure mechanism for a noncircular aperture is disclosed. The closure mechanism includes an extendible bellows coupled at one end to a noncircular duct and at its other end to a flange assembly having sealed grooves for establishing a high vacuum seal with the abutting surface of a facing flange which includes an aperture forming part of the system to be evacuated. A plurality of generally linear arrangements of pivotally coupled linkages and piston combinations are mounted around the outer surface of the duct and aligned along the length thereof. Each of the piston/linkage assemblies is adapted to engage the flange assembly by means of a respective piston and is further coupled to a remote controlled piston drive shaft to permit each of the linkages positioned on a respective flat outer surface of the duct to simultaneously and uniformly displace a corresponding piston and the flange assembly with which it is in contact along the length of the duct in extending the bellows to provide a high vacuum seal between the movable flange and the facing flange. A plurality of latch mechanisms are also pivotally mounted on the outside of the duct. A first end of each of the latch mechanisms is coupled to a remotely controlled latch control shaft for displacing the latch mechanism about its pivot point. In response to the pivoting displacement of the latch mechanism, a second end thereof is displaced so as to securely engage the facing flange.

  7. The Admissions Equity Struggle

    ERIC Educational Resources Information Center

    Freedman, Eric

    2012-01-01

    It has been a long, litigious road from Heman Sweatt, an African-American mail carrier who wanted to attend the prestigious, all-White law school at the University of Texas at Austin in 1946, to Abigail Fisher, a White high school student who failed to win undergraduate admission to the same university a half-century later. Depending on what the…

  8. Specificity mechanisms in the control of transcription.

    PubMed

    von Hippel, P H; Rees, W A; Rippe, K; Wilson, K S

    1996-04-16

    In this overview we analyze and illustrate the principles underlying some of the specificity mechanisms that control the initiation, elongation, and termination phases of transcription. Thermodynamic mechanisms dominate in the first steps of initiation, where promoters at various levels of activation can be considered to be in competition for a limiting supply of core RNA polymerase. In the later stages of initiation, as well as in elongation and termination, the regulatory mechanisms that control specificity are largely kinetic, involving rate competition between branching reaction pathways where the outcome depends on the rates (and equilibria) of reaction and interconversion of different forms of the transcription complex. Elongation complexes are very stable at most positions along the DNA template, meaning that only RNA chain elongation (and editing) can occur at these positions. However, the stability of transcription complexes decreases abruptly when termination sequences are encountered, and here the outcome can be easily switched between elongation and termination (RNA release) by minor changes in the relative rates of these competing processes. Cis effectors, defined as sites at which regulatory proteins bind to upstream activation loci on either the DNA or the nascent RNA, play important roles in the control of both initiation and of the elongation-termination decision. Examples, drawn from studies of phage lambda N-dependent antitermination and E. coli rho-dependent termination processes, illustrate the flexibility and additivity of regulatory components within control mechanisms in transcription that involve multiple determinants. The generality of such regulatory principles are stressed.

  9. Stress controls the mechanics of collagen networks

    PubMed Central

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M.; Fabry, Ben; Weitz, David A.; MacKintosh, Fred C.

    2015-01-01

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress–strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks. PMID:26195769

  10. Stress controls the mechanics of collagen networks.

    PubMed

    Licup, Albert James; Münster, Stefan; Sharma, Abhinav; Sheinman, Michael; Jawerth, Louise M; Fabry, Ben; Weitz, David A; MacKintosh, Fred C

    2015-08-04

    Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress-strain relationship, although the origins of this nonlinearity remain unknown. Here, we show that the nonlinear stiffening of reconstituted type I collagen networks is controlled by the applied stress and that the network stiffness becomes surprisingly insensitive to network concentration. We demonstrate how a simple model for networks of elastic fibers can quantitatively account for the mechanics of reconstituted collagen networks. Our model points to the important role of normal stresses in determining the nonlinear shear elastic response, which can explain the approximate exponential relationship between stress and strain reported for collagenous tissues. This further suggests principles for the design of synthetic fiber networks with collagen-like properties, as well as a mechanism for the control of the mechanics of such networks.

  11. Endoscope shaft-rigidity control mechanism: "FORGUIDE".

    PubMed

    Loeve, Arjo J; Plettenburg, Dick H; Breedveld, Paul; Dankelman, Jenny

    2012-02-01

    Recent developments in flexible endoscopy and other fields of medical technology have raised the need for compact slender shafts that can be made rigid and compliant at will. A novel compact mechanism, named FORGUIDE, with this functionality was developed. The FORGUIDE shaft rigidifies due to friction between a ring of cables situated between a spring and an inflated tube. A mathematical model for the FORGUIDE mechanism working principle was made and used to obtain understanding of this mechanism, predict the maximum rigidity of a FORGUIDE shaft design, and tune its design variables. The mathematical model gave suggestions for significant performance improvement by fine-tuning the design. A prototype FORGUIDE shaft was built and put to a series of bench tests. These tests showed that the FORGUIDE mechanism provides a reliable and simple way to control the rigidity of a flexible shaft.

  12. Remote controlled vacuum joint closure mechanism

    DOEpatents

    Doll, D.W.; Hager, E.R.

    1984-02-22

    A remotely operable and maintainable vacuum joint closure mechanism for a noncircular aperture is disclosed. The closure mechanism includes an extendible bellows coupled at one end to a noncircular duct and at its other end to a flange assembly having sealed grooves for establishing a high vacuum seal with the abutting surface of a facing flange which includes an aperture forming part of the system to be evacuated. A plurality of generally linear arrangements of pivotally coupled linkages and piston combinations are mounted around the outer surface of the duct and aligned along the length thereof. Each of the piston/linkage assemblies is adapted to engage the flange assembly by means of a respective piston and is further coupled to a remote controlled piston drive shaft to permit each of the linkages positioned on a respective flat outer surface of the duct to simultaneously and uniformly displace a corresponding piston and the flange assembly with which it is in contact along the length of the duct in extending the bellows to provide a high vacuum seal between the movable flange and the facing flange. A plurality of latch mechanisms are also pivotally mounted on the outside of the duct. A first end of each of the latch mechanisms is coupled to a remotely controlled latch control shaft for displacing the latch mechanism about its pivot point. In response to the pivoting displacement of the latch mechanism, a second end thereof is displaced so as to securely engage the facing flange and maintain the high vacuum seal established by the displacement of the flange assembly and extension of the bellows without displacing the entire duct.

  13. Admissions Criteria in Teacher Education.

    ERIC Educational Resources Information Center

    Schwanke, Dean

    1981-01-01

    A review of the literature on the topic of admissions criteria in teacher education is presented. Bibliographic annotations review surveys, studies, models, and guidelines on various aspects of admissions criteria, as well as attracting and retaining quality students. (JN)

  14. Fully Mechanically Controlled Automated Electron Microscopic Tomography

    PubMed Central

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-01-01

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins’ functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000–160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging. PMID:27403922

  15. Fully Mechanically Controlled Automated Electron Microscopic Tomography.

    PubMed

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-07-11

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins' functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000-160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.

  16. Fully Mechanically Controlled Automated Electron Microscopic Tomography

    NASA Astrophysics Data System (ADS)

    Liu, Jinxin; Li, Hongchang; Zhang, Lei; Rames, Matthew; Zhang, Meng; Yu, Yadong; Peng, Bo; Celis, César Díaz; Xu, April; Zou, Qin; Yang, Xu; Chen, Xuefeng; Ren, Gang

    2016-07-01

    Knowledge of three-dimensional (3D) structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins’ functions; but their structures are difficult to determine. Electron tomography (ET) provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional (3D) reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification (approximately 50,000–160,000×) and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral (PI) control algorithm. The validations by both negative staining (NS) and cryo-electron microscopy (cryo-EM) suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.

  17. Temperature-Controlled Clamping and Releasing Mechanism

    NASA Technical Reports Server (NTRS)

    Rosing, David; Ford, Virginia

    2005-01-01

    A report describes the development of a mechanism that automatically clamps upon warming and releases upon cooling between temperature limits of approx. =180 K and approx. =293 K. The mechanism satisfied a need specific to a program that involved repeated excursions of a spectrometer between a room-temperature atmospheric environment and a cryogenic vacuum testing environment. The mechanism was also to be utilized in the intended application of the spectrometer, in which the spectrometer would be clamped for protection during launch of a spacecraft and released in the cold of outer space to allow it to assume its nominal configuration for scientific observations. The mechanism is passive in the sense that its operation does not depend on a control system and does not require any power other than that incidental to heating and cooling. The clamping and releasing action is effected by bolt-preloaded stacks of shape-memory-alloy (SMA) cylinders. In designing this mechanism, as in designing other, similar SMA mechanisms, it was necessary to account for the complex interplay among thermal expansion, elastic and inelastic deformation under load, and SMA thermomechanical properties.

  18. Mechanical control of tissue and organ development

    PubMed Central

    Mammoto, Tadanori; Ingber, Donald E.

    2010-01-01

    Many genes and molecules that drive tissue patterning during organogenesis and tissue regeneration have been discovered. Yet, we still lack a full understanding of how these chemical cues induce the formation of living tissues with their unique shapes and material properties. Here, we review work based on the convergence of physics, engineering and biology that suggests that mechanical forces generated by living cells are as crucial as genes and chemical signals for the control of embryological development, morphogenesis and tissue patterning. PMID:20388652

  19. Fuel injection pump with spill control mechanism

    SciTech Connect

    Djordjevic, I.

    1987-02-24

    This patent describes a rotary fuel injection pump for an internal combustion engine, having a housing, a rotor rotatable in the housing, a charge pump having radially extending plunger bores in the rotor and a plunger pump for each plunger bore having a pumping plunger reciprocable in the bore. The pumping plungers have outward fuel intake strokes and inward fuel delivery strokes for supplying high pressure charges of fuel for fuel injection. A cam ring surrounds the rotor and is engageable with the plunger pumps to reciprocate the plungers as the rotor rotates. Bumping plunger timing means relatively angularly adjusts the cam ring and rotor adjusting the pumping plunger timing. A spill control mechanism has spill valve means connected to the charge pump for spill control of the high pressure charges of fuel. The improvement described here wherein the spill valve means comprises at least one rotary spill valve having a valve bore in the rotor connected to the charge pump and a rotary spill valve member rotatably mounted within the valve bore. The spill control mechanism comprises first means for rotating each rotary spill valve member in unison with the rotor and in synchronism with the reciprocable movement of the pumping plungers for spill control of the high pressure charges of fuel. The pumping plunger timing means and the first means provide for separate relative angular adjustment of the cam ring and rotor and relative angular adjustment of the rotary spill valve member of at least the one rotary spill valve and the rotor.

  20. [Feedback control mechanisms of plant cell expansion

    SciTech Connect

    Cosgrove, D.J.

    1992-01-01

    We have generated considerable evidence for the significance of wall stress relaxation in the control of plant growth and found that several agents (gibberellin, light, genetic loci for dwarf stature) influence growth rate via alteration of wall relaxation. We have refined our methods for measuring wall relaxation and, moreover, have found that wall relaxation properties bear only a distance relationship to wall mechanical properties. We have garnered novel insights into the nature of cell expansion mechanisms by analyzing spontaneous fluctuations of plant growth rate in seedlings. These experiments involved the application of mathematical techniques for analyzing growth rate fluctuations and the development of new instrumentation for measuring and forcing plant growth in a controlled fashion. These studies conclude that growth rate fluctuations generated by the plant as consequence of a feedback control system. This conclusion has important implications for the nature of wall loosening processes and demands a different framework for thinking about growth control. It also implies the existence of a growth rate sensor.

  1. New Interference Mechanism Controls Ultracold Chemistry

    NASA Astrophysics Data System (ADS)

    Kendrick, Brian K.; Hazra, Jisha; Balakrishnan, N.

    2016-05-01

    A newly discovered interference mechanism has been shown to control the outcome of ultracold chemical reactions. The mechanism originates from the unique properties associated with ultracold collisions, namely: (1) isotropic (s-wave) scattering and (2) an effective quantization of the scattering phase shift (which originates from the bound state structure of the molecule). These two properties can lead to maximum constructive or destructive interference between two interfering reaction pathways (such as exchange and non-exchange in systems with two or more identical nuclei). If the molecular system exhibits a conical intersection, then the associated geometric phase is shown to act as a ``quantum switch'' which can turn the reactivity on or off. Reaction rate coefficients for the O + OH --> H + O2 and H + H2, reactions are presented which explicitly demonstrate the effect. Experimentalists might exploit this new mechanism to control ultracold reactions by the application of external electric or magnetic fields or by the selection of a particular nuclear spin state. This work was supported in part by the LDRD program (Grant No. 20140309ER) at LANL (B.K.) and by NSF Grant PHY-1505557 (N.B.) and ARO MURI Grant No. W911NF-12-1-0476 (N.B.).

  2. Stirling engine control mechanism and method

    DOEpatents

    Dineen, John J.

    1983-01-01

    A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

  3. Optimal Control of Active Recoil Mechanisms

    DTIC Science & Technology

    1977-02-01

    forces from 25 to 2.5% for lower zones and cavitation was avoided for zone 8. Tachometer feedback was shown to be effective for low zones. The...concept of feedback control system coupled with optimization procedure to design recoil mechanisms was demonstrated to be an efficient and very effective ...122o •nl260 .01300 .01340 .01380 • ouzo #01460 •01500 •01540 •01580 •0162" .0166 i 309o,6 504P.6 9964.5 10075,9 39121.5 75397.3

  4. 40 CFR 89.604 - Conditional admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., the importer must store the nonroad engine at a location where the Administrator has reasonable access...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Importation of Nonconforming Nonroad Engines § 89.604 Conditional admission. (a) A nonroad engine offered for importation under §...

  5. Dynamic congestion control mechanisms for MPLS networks

    NASA Astrophysics Data System (ADS)

    Holness, Felicia; Phillips, Chris I.

    2001-02-01

    Considerable interest has arisen in congestion control through traffic engineering from the knowledge that although sensible provisioning of the network infrastructure is needed, together with sufficient underlying capacity, these are not sufficient to deliver the Quality of Service required for new applications. This is due to dynamic variations in load. In operational Internet Protocol (IP) networks, it has been difficult to incorporate effective traffic engineering due to the limited capabilities of the IP technology. In principle, Multiprotocol Label Switching (MPLS), which is a connection-oriented label swapping technology, offers new possibilities in addressing the limitations by allowing the operator to use sophisticated traffic control mechanisms. This paper presents a novel scheme to dynamically manage traffic flows through the network by re-balancing streams during periods of congestion. It proposes management-based algorithms that will allow label switched routers within the network to utilize mechanisms within MPLS to indicate when flows are starting to experience frame/packet loss and then to react accordingly. Based upon knowledge of the customer's Service Level Agreement, together with instantaneous flow information, the label edge routers can then instigate changes to the LSP route and circumvent congestion that would hitherto violate the customer contacts.

  6. Electrochemical biofilm control: mechanism of action

    PubMed Central

    Istanbullu, Ozlem; Babauta, Jerome; Nguyen, Hung Duc; Beyenal, Haluk

    2014-01-01

    Although it has been previously demonstrated that an electrical current can be used to control biofilm growth on metal surfaces, the literature results are conflicting and there is no accepted mechanism of action. One of the suggested mechanisms is the production of hydrogen peroxide (H2O2) on metal surfaces. However, there are literature studies in which H2O2 could not be detected in the bulk solution. This is most likely because H2O2 was produced at a low concentration near the surface and could not be detected in the bulk solution. The goals of this research were (1) to develop a well-controlled system to explain the mechanism of action of the bioelectrochemical effect on 316L stainless steel (SS) surfaces and (2) to test whether the produced H2O2 can reduce cell growth on metal surfaces. It was found that H2O2 was produced near 316L SS surfaces when a negative potential was applied. The H2O2 concentration increased towards the surface, while the dissolved oxygen decreased when the SS surface was polarized to −600 mVAg/AgCl. When polarized and non-polarized surfaces with identical Pseudomonas aeruginosa PAO1 biofilms were continuously fed with air-saturated growth medium, the polarized surfaces showed minimal biofilm growth while there was significant biofilm growth on the non-polarized surfaces. Although there was no detectable H2O2 in the bulk solution, it was found that the surface concentration of H2O2 was able to prevent biofilm growth. PMID:22827804

  7. Trends in Staphylococcus aureus bacteraemia and impacts of infection control practices including universal MRSA admission screening in a hospital in Scotland, 2006–2010: retrospective cohort study and time-series intervention analysis

    PubMed Central

    Edwards, Becky; López-Lozano, José-Maria; Gould, Ian

    2012-01-01

    Objectives To describe secular trends in Staphylococcus aureus bacteraemia (SAB) and to assess the impacts of infection control practices, including universal methicillin-resistant Staphylococcus aureus (MRSA) admission screening on associated clinical burdens. Design Retrospective cohort study and multivariate time-series analysis linking microbiology, patient management and health intelligence databases. Setting Teaching hospital in North East Scotland. Participants All patients admitted to Aberdeen Royal Infirmary between 1 January 2006 and 31 December 2010: n=420 452 admissions and 1 430 052 acute occupied bed days (AOBDs). Intervention Universal admission screening programme for MRSA (August 2008) incorporating isolation and decolonisation. Primary and secondary measures Hospital-wide prevalence density, hospital-associated incidence density and death within 30 days of MRSA or methicillin-sensitive Staphylococcus aureus (MSSA) bacteraemia. Results Between 2006 and 2010, prevalence density of all SAB declined by 41%, from 0.73 to 0.50 cases/1000 AOBDs (p=0.002 for trend), and 30-day mortality from 26% to 14% (p=0.013). Significant reductions were observed in MRSA bacteraemia only. Overnight admissions screened for MRSA rose from 43% during selective screening to >90% within 4 months of universal screening. In multivariate time-series analysis (R2 0.45 to 0.68), universal screening was associated with a 19% reduction in prevalence density of MRSA bacteraemia (−0.035, 95% CI −0.049 to −0.021/1000 AOBDs; p<0.001), a 29% fall in hospital-associated incidence density (−0.029, 95% CI −0.035 to −0.023/1000 AOBDs; p<0.001) and a 46% reduction in 30-day mortality (−15.6, 95% CI −24.1% to −7.1%; p<0.001). Positive associations with fluoroquinolone and cephalosporin use suggested that antibiotic stewardship reduced prevalence density of MRSA bacteraemia by 0.027 (95% CI 0.015 to 0.039)/1000 AOBDs. Rates of MSSA bacteraemia were not

  8. 32. 48' MILL STEAM ENGINE ADMISSION BOX (?), STEAM VALVE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. 48' MILL STEAM ENGINE ADMISSION BOX (?), STEAM VALVE, AND REVERSING MECHANISM LIFTING CYLINDER. - U.S. Steel Homestead Works, 48" Plate Mill, Along Monongahela River, Homestead, Allegheny County, PA

  9. Spatial constancy mechanisms in motor control

    PubMed Central

    Medendorp, W. Pieter

    2011-01-01

    The success of the human species in interacting with the environment depends on the ability to maintain spatial stability despite the continuous changes in sensory and motor inputs owing to movements of eyes, head and body. In this paper, I will review recent advances in the understanding of how the brain deals with the dynamic flow of sensory and motor information in order to maintain spatial constancy of movement goals. The first part summarizes studies in the saccadic system, showing that spatial constancy is governed by a dynamic feed-forward process, by gaze-centred remapping of target representations in anticipation of and across eye movements. The subsequent sections relate to other oculomotor behaviour, such as eye–head gaze shifts, smooth pursuit and vergence eye movements, and their implications for feed-forward mechanisms for spatial constancy. Work that studied the geometric complexities in spatial constancy and saccadic guidance across head and body movements, distinguishing between self-generated and passively induced motion, indicates that both feed-forward and sensory feedback processing play a role in spatial updating of movement goals. The paper ends with a discussion of the behavioural mechanisms of spatial constancy for arm motor control and their physiological implications for the brain. Taken together, the emerging picture is that the brain computes an evolving representation of three-dimensional action space, whose internal metric is updated in a nonlinear way, by optimally integrating noisy and ambiguous afferent and efferent signals. PMID:21242137

  10. Hospital admissions before and after shipyard closure.

    PubMed Central

    Iversen, L.; Sabroe, S.; Damsgaard, M. T.

    1989-01-01

    To determine the effect of job loss on health an investigation was made of admissions to hospitals in 887 men five years before and three years after the closure of a Danish shipyard. The control group comprised 441 men from another shipyard. The information on hospital admissions was obtained from the Danish national register of patients. The relative risk of admission in the control group dropped significantly in terms of the number of men admitted from the study group from 1.29 four to five years before closure to 0.74 in the three years after closure. This was especially true of admissions due to accidents (1.33 to 0.46) and diseases of the digestive system (4.53 to 1.03). For diseases of the circulatory system, particularly cardiovascular diseases, the relative risk increased from 0.8 to 1.60, and from 1.0 to 2.6 respectively. These changes in risk of illness after redundancy are probably a consequence of a change from the effects of a high risk work environment to the effects of psychosocial stresses such as job insecurity and unemployment. PMID:2511968

  11. The Changing College Admissions Scene.

    ERIC Educational Resources Information Center

    Sjogren, Cliff

    1983-01-01

    Discusses the status of college admissions and some of the forces that influenced college admissions policies during each of four three-year periods: the Sputnik Era (1957-60), the Postwar Baby Boom Era (1964-67), the "New Groups" Era (1971-74), and the Stable Enrollment Era (1978-81). (PGD)

  12. Optimal Admission to Higher Education

    ERIC Educational Resources Information Center

    Albaek, Karsten

    2017-01-01

    This paper analyses admission decisions when students from different high school tracks apply for admission to university programmes. I derive a criterion that is optimal in the sense that it maximizes the graduation rates of the university programmes. The paper contains an empirical analysis that documents the relevance of theory and illustrates…

  13. Mechanically and optically controlled graphene valley filter

    SciTech Connect

    Qi, Fenghua; Jin, Guojun

    2014-05-07

    We theoretically investigate the valley-dependent electronic transport through a graphene monolayer modulated simultaneously by a uniform uniaxial strain and linearly polarized light. Within the Floquet formalism, we calculate the transmission probabilities and conductances of the two valleys. It is found that valley polarization can appear only if the two modulations coexist. Under a proper stretching of the sample, the ratio of the light intensity and the light frequency squared is important. If this quantity is small, the electron transport is mainly contributed by the valley-symmetric central band and the conductance is valley unpolarized; but when this quantity is large, the valley-asymmetric sidebands also take part in the transport and the valley polarization of the conductance appears. Furthermore, the degree of the polarization can be tuned by the strain strength, light intensity, and light frequency. It is proposed that the detection of the valley polarization can be realized utilizing the valley beam splitting. Thus, a graphene monolayer can be used as a mechanically and optically controlled valley filter.

  14. Brain mechanisms that control sleep and waking

    NASA Astrophysics Data System (ADS)

    Siegel, Jerome

    This review paper presents a brief historical survey of the technological and early research that laid the groundwork for recent advances in sleep-waking research. A major advance in this field occurred shortly after the end of World War II with the discovery of the ascending reticular activating system (ARAS) as the neural source in the brain stem of the waking state. Subsequent research showed that the brain stem activating system produced cortical arousal via two pathways: a dorsal route through the thalamus and a ventral route through the hypothalamus and basal forebrain. The nuclei, pathways, and neurotransmitters that comprise the multiple components of these arousal systems are described. Sleep is now recognized as being composed of two very different states: rapid eye movements (REMs) sleep and non-REM sleep. The major findings on the neural mechanisms that control these two sleep states are presented. This review ends with a discussion of two current views on the function of sleep: to maintain the integrity of the immune system and to enhance memory consolidation.

  15. Cellular Mechanisms of Ciliary Length Control

    PubMed Central

    Keeling, Jacob; Tsiokas, Leonidas; Maskey, Dipak

    2016-01-01

    Cilia and flagella are evolutionarily conserved, membrane-bound, microtubule-based organelles on the surface of most eukaryotic cells. They play important roles in coordinating a variety of signaling pathways during growth, development, cell mobility, and tissue homeostasis. Defects in ciliary structure or function are associated with multiple human disorders called ciliopathies. These diseases affect diverse tissues, including, but not limited to the eyes, kidneys, brain, and lungs. Many processes must be coordinated simultaneously in order to initiate ciliogenesis. These include cell cycle, vesicular trafficking, and axonemal extension. Centrioles play a central role in both cell cycle progression and ciliogenesis, making the transition between basal bodies and mitotic spindle organizers integral to both processes. The maturation of centrioles involves a functional shift from cell division toward cilium nucleation which takes place concurrently with its migration and fusion to the plasma membrane. Several proteinaceous structures of the distal appendages in mother centrioles are required for this docking process. Ciliary assembly and maintenance requires a precise balance between two indispensable processes; so called assembly and disassembly. The interplay between them determines the length of the resulting cilia. These processes require a highly conserved transport system to provide the necessary substances at the tips of the cilia and to recycle ciliary turnover products to the base using a based microtubule intraflagellar transport (IFT) system. In this review; we discuss the stages of ciliogenesis as well as mechanisms controlling the lengths of assembled cilia. PMID:26840332

  16. Adaptive mechanically controlled lubrication mechanism found in articular joints.

    PubMed

    Greene, George W; Banquy, Xavier; Lee, Dong Woog; Lowrey, Daniel D; Yu, Jing; Israelachvili, Jacob N

    2011-03-29

    Articular cartilage is a highly efficacious water-based tribological system that is optimized to provide low friction and wear protection at both low and high loads (pressures) and sliding velocities that must last over a lifetime. Although many different lubrication mechanisms have been proposed, it is becoming increasingly apparent that the tribological performance of cartilage cannot be attributed to a single mechanism acting alone but on the synergistic action of multiple "modes" of lubrication that are adapted to provide optimum lubrication as the normal loads, shear stresses, and rates change. Hyaluronic acid (HA) is abundant in cartilage and synovial fluid and widely thought to play a principal role in joint lubrication although this role remains unclear. HA is also known to complex readily with the glycoprotein lubricin (LUB) to form a cross-linked network that has also been shown to be critical to the wear prevention mechanism of joints. Friction experiments on porcine cartilage using the surface forces apparatus, and enzymatic digestion, reveal an "adaptive" role for an HA-LUB complex whereby, under compression, nominally free HA diffusing out of the cartilage becomes mechanically, i.e., physically, trapped at the interface by the increasingly constricted collagen pore network. The mechanically trapped HA-LUB complex now acts as an effective (chemically bound) "boundary lubricant"--reducing the friction force slightly but, more importantly, eliminating wear damage to the rubbing/shearing surfaces. This paper focuses on the contribution of HA in cartilage lubrication; however, the system as a whole requires both HA and LUB to function optimally under all conditions.

  17. Heavy Equipment Mechanic Program Standards.

    ERIC Educational Resources Information Center

    Georgia Univ., Athens. Dept. of Vocational Education.

    This publication contains statewide standards for the heavy equipment mechanic program in Georgia. The standards are divided into 12 categories: foundations (philosophy, purpose, goals, program objectives, availability, evaluation); admissions (admission requirements, provisional admission requirements, recruitment, evaluation and planning);…

  18. 28 CFR 549.42 - Involuntary admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICES Administrative Safeguards for Psychiatric Treatment and Medication § 549.42 Involuntary admission... voluntarily consent either to psychiatric admission or to medication, is subject to judicial...

  19. 32 CFR 242.5 - Admission procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... HEALTH SCIENCES § 242.5 Admission procedures. (a) Application—(1) Civilians. Civilians seeking admission to the School of Medicine shall make direct application following instructions published in...

  20. On some control problems in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Abergel, F.; Temam, R.

    The issue of minimizing turbulence in an evolutionary Navier-Stokes flow is addressed from the point of view of optimal control. Theoretical results are derived for various physical situations: distributed control, Benard-type problems with boundary control, and flow in a channel. For each case considered, the results include the formulation of the problem as an optimal control problem and proof of the existence of an optimal control (which is not expected to be unique). Finally, a numerical algorithm based on the gradient method for the corresponding cost function is described.

  1. Controlled Unusual Stiffness of Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Lee, Wooju; Kang, Da-Young; Song, Jihwan; Moon, Jun Hyuk; Kim, Dongchoul

    2016-02-01

    Mechanical metamaterials that are engineered with sub-unit structures present unusual mechanical properties depending on the loading direction. Although they show promise, their practical utility has so far been somewhat limited because, to the best of our knowledge, no study about the potential of mechanical metamaterials made from sophisticatedly tailored sub-unit structures has been made. Here, we present a mechanical metamaterial whose mechanical properties can be systematically designed without changing its chemical composition or weight. We study the mechanical properties of triply periodic bicontinuous structures whose detailed sub-unit structure can be precisely fabricated using various sub-micron fabrication methods. Simulation results show that the effective wave velocity of the structures along with different directions can be designed to introduce the anisotropy of stiffness by changing a volume fraction and aspect ratio. The ratio of Young’s modulus to shear modulus can be increased by up to at least 100, which is a 3500% increase over that of isotropic material (2.8, acrylonitrile butadiene styrene). Furthermore, Poisson’s ratio of the constituent material changes the ratio while Young’s modulus does not influence it. This study presents the promising potential of mechanical metamaterials for versatile industrial and biomedical applications.

  2. Finite-time Control of One-link Mechanical System

    NASA Astrophysics Data System (ADS)

    Matoba, Shunsuke; Nakamura, Nami; Nakamura, Hisakazu; Akiba, Hideyuki

    This paper considers finite-time position control of an one-link mechanical system. The system is modeled by discontinuous differential equations. In this paper, we prove that the Nakamura's local homogeneous controller based on a control Lyapunov function is valid to the position control of the robot manipulators, and show the effectiveness of the controller by experiments.

  3. Control of flexible systems and principles of structural mechanics

    NASA Astrophysics Data System (ADS)

    Oz, H.

    1984-08-01

    Common control approaches for flexible systems are evaluated in regards to their compatibility with the fundamentals of mechanics of structural systems. It is shown that depending on the formulation, control problems may be ill-posed leading to incompatibilities with the basic laws of mechanics. In an effort to eliminate the incompatibilities constructively, it is found that a unique well-posed method of control that is fully in compliance with the fundamentals of structural mechanics exists.

  4. Passive dynamic controllers for nonlinear mechanical systems

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Wu, Shih-Chin; Phan, Minh; Longman, Richard W.

    1991-01-01

    A methodology for model-independant controller design for controlling large angular motion of multi-body dynamic systems is outlined. The controlled system may consist of rigid and flexible components that undergo large rigid body motion and small elastic deformations. Control forces/torques are applied to drive the system and at the same time suppress the vibration due to flexibility of the components. The proposed controller consists of passive second-order systems which may be designed with little knowledge of the system parameter, even if the controlled system is nonlinear. Under rather general assumptions, the passive design assures that the closed loop system has guaranteed stability properties. Unlike positive real controller design, stabilization can be accomplished without direct velocity feedback. In addition, the second-order passive design allows dynamic feedback controllers with considerable freedom to tune for desired system response, and to avoid actuator saturation. After developing the basic mathematical formulation of the design methodology, simulation results are presented to illustrate the proposed approach to a flexible six-degree-of-freedom manipulator.

  5. Computer aided control of a mechanical arm

    NASA Technical Reports Server (NTRS)

    Derocher, W. L., Jr.; Zermuehlen, r. O.

    1979-01-01

    A method for computer-aided remote control of a six-degree-of-freedom manipulator arm involved in the on-orbit servicing of a spacecraft is presented. The control configuration features a supervisory type of control in which each of the segments of a module exchange trajectory is controlled automatically under human supervision, with manual commands to proceed to the next step and in the event of a failure or undesirable outcome. The implementation of the supervisory system is discussed in terms of necessary onboard and ground- or Orbiter-based hardware and software, and a one-g demonstration system built to allow further investigation of system operation is described. Possible applications of the system include the construction of satellite solar power systems, environmental testing and the control of heliostat solar power stations.

  6. Critical length scale controls adhesive wear mechanisms

    PubMed Central

    Aghababaei, Ramin; Warner, Derek H.; Molinari, Jean-Francois

    2016-01-01

    The adhesive wear process remains one of the least understood areas of mechanics. While it has long been established that adhesive wear is a direct result of contacting surface asperities, an agreed upon understanding of how contacting asperities lead to wear debris particle has remained elusive. This has restricted adhesive wear prediction to empirical models with limited transferability. Here we show that discrepant observations and predictions of two distinct adhesive wear mechanisms can be reconciled into a unified framework. Using atomistic simulations with model interatomic potentials, we reveal a transition in the asperity wear mechanism when contact junctions fall below a critical length scale. A simple analytic model is formulated to predict the transition in both the simulation results and experiments. This new understanding may help expand use of computer modelling to explore adhesive wear processes and to advance physics-based wear laws without empirical coefficients. PMID:27264270

  7. The mechanical control of nervous system development.

    PubMed

    Franze, Kristian

    2013-08-01

    The development of the nervous system has so far, to a large extent, been considered in the context of biochemistry, molecular biology and genetics. However, there is growing evidence that many biological systems also integrate mechanical information when making decisions during differentiation, growth, proliferation, migration and general function. Based on recent findings, I hypothesize that several steps during nervous system development, including neural progenitor cell differentiation, neuronal migration, axon extension and the folding of the brain, rely on or are even driven by mechanical cues and forces.

  8. 22 CFR 229.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Admission. 229.300 Section 229.300 Foreign... and Recruitment Prohibited § 229.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§...

  9. 22 CFR 229.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Admission. 229.300 Section 229.300 Foreign... and Recruitment Prohibited § 229.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§...

  10. 22 CFR 146.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Admission. 146.300 Section 146.300 Foreign... Recruitment Prohibited § 146.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§ 146.300...

  11. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Admission. 1042.300 Section 1042.300 Energy DEPARTMENT OF... Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient to which §§ 1042.300 through...

  12. 44 CFR 68.9 - Admissible evidence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Admissible evidence. 68.9 Section 68.9 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF... admissible. (b) Documentary and oral evidence shall be admissible. (c) Admissibility of non-expert...

  13. College Admissions Policies for the 1970's.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, New York, NY.

    The papers included in this collection are (1) "Problems and Issues Confronting the Admissions Community" by Clyde Vroman; (2) "Frozen Assumptions in Admissions" by B. Alden Thresher; (3) "The Effect of Federal Programs on Admissions Policies" by John F. Morse; (4) "State Plans for Higher Education and Their Influence on Admissions" by Charles W.…

  14. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  15. [Classical dengue transmission dynamics involving mechanical control and prophylaxis].

    PubMed

    Toro-Zapata, Hernán D; Restrepo, Leonardo D; Vergaño-Salazar, Juan G; Muñoz-Loaiza, Aníbal

    2010-12-01

    Dengue fever transmission dynamics were studied in an endemic region considering the use of preventative measures and mechanical control in reducing transmission of the disease. A system of ordinary differential equations was proposed, describing the dynamics and their evolution as determined by numerical simulation. Different mechanical control and prophylaxis strategies were compared to the situation without control. The basic reproduction number R₀ was determined R₀ to show that if R₀ > 1 there would be a risk of an epidemic and otherwise the disease would have low impact levels. The basic reproduction number helps determine the dynamics' future pattern and contrast the results so obtained with those obtained numerically. It was concluded that although prophylaxis and mechanical control alone provide effective results in controlling the disease, if both controls are combined then infection levels become significantly reduced. Around 60 % mechanical control and prevention levels are needed to provide suitable results in controlling dengue outbreaks.

  16. 11. LAUNCH CONTROL SUPPORT BUILDING. INTERIOR OF MECHANICAL ROOM. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. LAUNCH CONTROL SUPPORT BUILDING. INTERIOR OF MECHANICAL ROOM. VIEW TO SOUTHEAST. - Minuteman III ICBM Launch Control Facility November-1, 1.5 miles North of New Raymer & State Highway 14, New Raymer, Weld County, CO

  17. Mechanisms for leaf control of gas exchange

    SciTech Connect

    Mansfield, T.A.; Davies, W.J.

    1985-03-01

    Several mechanisms enable leaf stomata to optimize water loss with respect to carbon gain. Stomatal responses to environmental variation constitute a plant's first and second lines of defense against damaging water deficits. Changes in the concentrations of endogenous growth regulations and their influence on stomata may well be important to both defense strategies.

  18. Control Engineering Analysis of Mechanical Pitch Systems

    NASA Astrophysics Data System (ADS)

    Bernicke, Olaf; Gauterin, Eckhard; Schulte, Horst; Zajac, Michal

    2014-12-01

    With the help of a local stability analysis the coefficient range of a discrete damper, used for centrifugal forced, mechanical pitch system of small wind turbines (SWT), is gained for equilibrium points. - By a global stability analysis the gained coefficient range can be validated. An appropriate approach by Takagi-Sugeno is presented in the paper.

  19. Manipulator control and mechanization: A telerobot subsystem

    NASA Technical Reports Server (NTRS)

    Hayati, S.; Wilcox, B.

    1987-01-01

    The short- and long-term autonomous robot control activities in the Robotics and Teleoperators Research Group at the Jet Propulsion Laboratory (JPL) are described. This group is one of several involved in robotics and is an integral part of a new NASA robotics initiative called Telerobot program. A description of the architecture, hardware and software, and the research direction in manipulator control is given.

  20. [Visual attention and its control mechanisms].

    PubMed

    Ogawa, Hirokazu

    2014-04-01

    Given the vast amount of visual information in visual scenes, the capacity of our brain to processes such scenes is severely limited. The core mechanism of selection is referred to as visual attention, and it has been the topic of intense investigation for over 25 years in experimental psychology and cognitive neuroscience. Visual attention is not a single, unitary mechanism, but consists of multiple subcomponents. Attention can be directed to various aspects of visual information, such as spatial location, features, or objects. Additionally, attention is guided by external factors such as the salience of stimuli, or whether we are able to move our attention volitionally. The purpose of this article is to review the status of these components of attentional guidance and how they interact with each other, with an emphasis on psychophysical studies.

  1. Geometric Computational Mechanics and Optimal Control

    DTIC Science & Technology

    2011-12-02

    methods. Further methods that depend on global optimization problems are in development and preliminary versions of these results, many of which...de la Sociedad Espanola de Matimatica Aplicada (SeMA), 50, 2010, pp 61-81. K. Flaßkamp, S. Ober-Blöbaum, M. Kobilarov, Solving optimal control...continuous setting. Consequently, globally optimal methods for computing optimal trajectories for vehicles with complex dynamics were developed. The

  2. Effects of anesthesia on cardiovascular control mechanisms.

    PubMed Central

    Vatner, S F

    1978-01-01

    The manner in which general anesthesia affects circulatory control was studied by examining the effects of commonly employed anesthetics on left ventricular function and distribution of cardiac output, and the extent to which responses to physiological and pharmacological stimuli are modified by general anesthesia. While commonly employed anesthetics affect almost every aspect of the circulatory system, the importance of general anesthesia on the circulation tends to be underestimated by considering only its direct effects. More important is the modification of the organism's integrative response to any perturbation. Major differences often directionally opposite, in responses of conscious and anesthetized animals were found for reflex control of the circulation, effects of hemorrhage and alterations in preload and after load. In addition, commonly employed pharmacologic agents, e.g., cardiac glycosdies, catecholamines, and morphine sulfate exerted differing actions in the conscious and anesthetized states. Thus, while it is generally held that the overall responses to complex physiological functions such as exercise or eating can be best described in the intact, conscious organism, the importance of conducting any experiment involving integrative control of the circulation in the conscious organism should also be recognized. PMID:363416

  3. Two Mechanisms to Avoid Control Conflicts Resulting from Uncoordinated Intent

    NASA Technical Reports Server (NTRS)

    Mishkin, Andrew H.; Dvorak, Daniel L.; Wagner, David A.; Bennett, Matthew B.

    2013-01-01

    This software implements a real-time access control protocol that is intended to make all connected users aware of the presence of other connected users, and which of them is currently in control of the system. Here, "in control" means that a single user is authorized and enabled to issue instructions to the system. The software The software also implements a goal scheduling mechanism that can detect situations where plans for the operation of a target system proposed by different users overlap and interact in conflicting ways. In such situations, the system can either simply report the conflict (rejecting one goal or the entire plan), or reschedule the goals in a way that does not conflict. The access control mechanism (and associated control protocol) is unique. Other access control mechanisms are generally intended to authenticate users, or exclude unauthorized access. This software does neither, and would likely depend on having some other mechanism to support those requirements.

  4. Control of Drop Motion by Mechanical Vibrations

    NASA Astrophysics Data System (ADS)

    Bestehorn, Michael

    2014-11-01

    Since the first experimental observations of Michael Faraday in 1831 it is known that a vibrating liquid may show an instability of its flat free surface with respect to oscillating regular surface patterns. We study thin liquid films on a horizontal substrate in the long wave approximation. The films are parametrically excited by mechanical horizontal or inclined oscillations. Inertia effects are taken into account and the standard thin film formulation is extended by a second equation for the vertically averaged mass flux. The films can be additionally unstable by Van der Waals forces on a partially wetting substrate, leading to the formation of drops. These drops can be manipulated by the vibrations to move in a desired direction. Linear results based on a damped complex valued Mathieu equation as well as fully nonlinear results using a reduced model will be presented, for more details see.

  5. An immunosurveillance mechanism controls cancer cell ploidy.

    PubMed

    Senovilla, Laura; Vitale, Ilio; Martins, Isabelle; Tailler, Maximilien; Pailleret, Claire; Michaud, Mickaël; Galluzzi, Lorenzo; Adjemian, Sandy; Kepp, Oliver; Niso-Santano, Mireia; Shen, Shensi; Mariño, Guillermo; Criollo, Alfredo; Boilève, Alice; Job, Bastien; Ladoire, Sylvain; Ghiringhelli, François; Sistigu, Antonella; Yamazaki, Takahiro; Rello-Varona, Santiago; Locher, Clara; Poirier-Colame, Vichnou; Talbot, Monique; Valent, Alexander; Berardinelli, Francesco; Antoccia, Antonio; Ciccosanti, Fabiola; Fimia, Gian Maria; Piacentini, Mauro; Fueyo, Antonio; Messina, Nicole L; Li, Ming; Chan, Christopher J; Sigl, Verena; Pourcher, Guillaume; Ruckenstuhl, Christoph; Carmona-Gutierrez, Didac; Lazar, Vladimir; Penninger, Josef M; Madeo, Frank; López-Otín, Carlos; Smyth, Mark J; Zitvogel, Laurence; Castedo, Maria; Kroemer, Guido

    2012-09-28

    Cancer cells accommodate multiple genetic and epigenetic alterations that initially activate intrinsic (cell-autonomous) and extrinsic (immune-mediated) oncosuppressive mechanisms. Only once these barriers to oncogenesis have been overcome can malignant growth proceed unrestrained. Tetraploidization can contribute to oncogenesis because hyperploid cells are genomically unstable. We report that hyperploid cancer cells become immunogenic because of a constitutive endoplasmic reticulum stress response resulting in the aberrant cell surface exposure of calreticulin. Hyperploid, calreticulin-exposing cancer cells readily proliferated in immunodeficient mice and conserved their increased DNA content. In contrast, hyperploid cells injected into immunocompetent mice generated tumors only after a delay, and such tumors exhibited reduced DNA content, endoplasmic reticulum stress, and calreticulin exposure. Our results unveil an immunosurveillance system that imposes immunoselection against hyperploidy in carcinogen- and oncogene-induced cancers.

  6. Somnambulism: Emergency Department Admissions Due to Sleepwalking-Related Trauma

    PubMed Central

    Sauter, Thomas C.; Veerakatty, Sajitha; Haider, Dominik G.; Geiser, Thomas; Ricklin, Meret E.; Exadaktylos, Aristomenis K.

    2016-01-01

    Introduction Somnambulism is a state of dissociated consciousness, in which the affected person is partially asleep and partially awake. There is pervasive public opinion that sleepwalkers are protected from hurting themselves. There have been few scientific reports of trauma associated with somnambulism and no published investigations on the epidemiology or trauma patterns associated with somnambulism. Methods We included all emergency department (ED) admissions to University Hospital Inselspital, Berne, Switzerland, from January 1, 2000, until August 11, 2015, when the patient had suffered a trauma associated with somnambulism. Demographic data (age, gender, nationality) and medical data (mechanism of injury, final diagnosis, hospital admission, mortality and medication on admission) were included. Results Of 620,000 screened ED admissions, 11 were associated with trauma and sleepwalking. Two patients (18.2%) had a history of known non-rapid eye movement parasomnias. The leading cause of admission was falls. Four patients required hospital admission for orthopedic injuries needing further diagnostic testing and treatment (36.4%). These included two patients with multiple injuries (18.2%). None of the admitted patients died. Conclusion Although sleepwalking seems benign in the majority of cases and most of the few injured patients did not require hospitalization, major injuries are possible. When patients present with falls of unknown origin, the possibility should be evaluated that they were caused by somnambulism. PMID:27833677

  7. Neural Control Mechanisms and Body Fluid Homeostasis

    NASA Technical Reports Server (NTRS)

    Johnson, Alan Kim

    1998-01-01

    The goal of the proposed research was to study the nature of afferent signals to the brain that reflect the status of body fluid balance and to investigate the central neural mechanisms that process this information for the activation of response systems which restore body fluid homeostasis. That is, in the face of loss of fluids from intracellular or extracellular fluid compartments, animals seek and ingest water and ionic solutions (particularly Na(+) solutions) to restore the intracellular and extracellular spaces. Over recent years, our laboratory has generated a substantial body of information indicating that: (1) a fall in systemic arterial pressure facilitates the ingestion of rehydrating solutions and (2) that the actions of brain amine systems (e.g., norepinephrine; serotonin) are critical for precise correction of fluid losses. Because both acute and chronic dehydration are associated with physiological stresses, such as exercise and sustained exposure to microgravity, the present research will aid in achieving a better understanding of how vital information is handled by the nervous system for maintenance of the body's fluid matrix which is critical for health and well-being.

  8. Symbiotic Control in Mechanical Bond Formation.

    PubMed

    Wang, Yuping; Sun, Junling; Liu, Zhichang; Nassar, Majed S; Botros, Youssry Y; Stoddart, J Fraser

    2016-09-26

    Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY(.+) units, the radical cationic state of 4,4'-bipyridinium (BIPY(2+) ) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY(.+) radical cations, while the metal itself, which is oxidized to Cu(I) , catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY(.+) radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium.

  9. Rapid Mechanically Controlled Rewiring of Neuronal Circuits

    PubMed Central

    Magdesian, Margaret H.; Lopez-Ayon, G. Monserratt; Mori, Megumi; Boudreau, Dominic; Goulet-Hanssens, Alexis; Sanz, Ricardo; Miyahara, Yoichi; Barrett, Christopher J.; Fournier, Alyson E.; De Koninck, Yves

    2016-01-01

    CNS injury may lead to permanent functional deficits because it is still not possible to regenerate axons over long distances and accurately reconnect them with an appropriate target. Using rat neurons, microtools, and nanotools, we show that new, functional neurites can be created and precisely positioned to directly (re)wire neuronal networks. We show that an adhesive contact made onto an axon or dendrite can be pulled to initiate a new neurite that can be mechanically guided to form new synapses at up to 0.8 mm distance in <1 h. Our findings challenge current understanding of the limits of neuronal growth and have direct implications for the development of new therapies and surgical techniques to achieve functional regeneration. SIGNIFICANCE STATEMENT Brain and spinal cord injury may lead to permanent disability and death because it is still not possible to regenerate neurons over long distances and accurately reconnect them with an appropriate target. Using microtools and nanotools we have developed a new method to rapidly initiate, elongate, and precisely connect new functional neuronal circuits over long distances. The extension rates achieved are ≥60 times faster than previously reported. Our findings have direct implications for the development of new therapies and surgical techniques to achieve functional regeneration after trauma and in neurodegenerative diseases. It also opens the door for the direct wiring of robust brain–machine interfaces as well as for investigations of fundamental aspects of neuronal signal processing and neuronal function. PMID:26791225

  10. Nanoengineering mechanically robust aerogels via control of foam morphology

    NASA Astrophysics Data System (ADS)

    Kucheyev, S. O.; Baumann, T. F.; Cox, C. A.; Wang, Y. M.; Satcher, J. H.; Hamza, A. V.; Bradby, J. E.

    2006-07-01

    Potential of aerogels for technological applications is often limited by their poor mechanical properties. Here, we demonstrate that alumina aerogel monoliths with excellent mechanical properties can be made by controlling the crystallographic phase, shape, and size of nanoligaments. In particular, we show that thermal processing of aerogels with a morphology of interconnected nanoleaflets causes dehydration and associated curling of the nanoleaflets, resulting in a dramatic improvement of mechanical properties. This study shows an effective way to control mechanical properties of the nanoporous solids that can be synthesized with ligaments having a quasi-two-dimensional shape, such as platelets, ribbons, or leaflets.

  11. Optimal Tuning for Disturbance Suppression Mechanism for Model Predictive Control

    NASA Astrophysics Data System (ADS)

    Tange, Yoshio; Nakazawa, Chikashi

    Disturbance suppression is one of most required performances in process control. We recently proposed a new disturbance suppression mechanism applicable for model predictive control in order to enhance disturbance suppression performance for ramp-like disturbances. The proposed method utilized the prediction error of controlled values and generates a disturbance compensation signal by a constant gain feedback. In this paper, we propose an improved version of the disturbance suppression mechanism by applying a low-pass filter and parameter tuning methods by which we can make the mechanism more tolerant to various disturbances such as ramp, step, and other supposable ones. We also show numerical simulation results with an oil distillation tower plant.

  12. Temporal control mechanism in equaled interval tapping.

    PubMed

    Yamada, M

    1996-05-01

    Subjects who were at intermediate levels of musical performance made equaled interval tapping in several tempos. The temporal fluctuation for the tapping was observed and analysed. The power spectrum of the fluctuation showed a critical phenomenon at around a frequency which corresponds to the period of 20 taps, for all tempos and all subjects, i.e., the slope of the spectrum was flat or had a positive value in the high frequency region above the critical frequency but it increased as the frequency decreased in the low frequency region below the critical frequency. Moreover, auto-regressive models and Akaike's information criterion were introduced to determine the critical tap number. The order of the best auto-regressive model for the temporal fluctuation data was distributed around 20 taps. These results show that the memory capacity of 20 taps governs the control of equaled interval tapping. To interpret the critical phenomenon of 20 taps with the memory capacity of the short term memory, the so called magic number seven, a simple chunking assumption was introduced; subjects might have unconsciously chunked every three taps during the tapping. If the chunking assumption is true, when subjects consciously chunk every seven taps, the memory capacity of taps should shift to about 50 taps. To test if the assumption is true or not, subjects made a three-beat rhythm tapping and a seven-beat rhythm tapping with equaled intervals. As a result, the memory capacity for these accented tappings were also estimated as 20 taps. This suggests that the critical phenomenon cannot be explained by the chunking assumption and the magic number seven, rather this finding suggests that there exists a memory capacity of 20 taps and this is used for equaled interval tapping.

  13. 32 CFR 242.5 - Admission procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... HEALTH SCIENCES § 242.5 Admission procedures. (a) Application—(1) Civilians. Civilians seeking admission... conditionally select candidates to fill available class spaces. Those conditionally selected shall be the...

  14. Control of chaos: methods and applications in mechanics.

    PubMed

    Fradkov, Alexander L; Evans, Robin J; Andrievsky, Boris R

    2006-09-15

    A survey of the field related to control of chaotic systems is presented. Several major branches of research that are discussed are feed-forward ('non-feedback') control (based on periodic excitation of the system), the 'Ott-Grebogi-Yorke method' (based on the linearization of the Poincaré map), the 'Pyragas method' (based on a time-delayed feedback), traditional for control-engineering methods including linear, nonlinear and adaptive control. Other areas of research such as control of distributed (spatio-temporal and delayed) systems, chaotic mixing are outlined. Applications to control of chaotic mechanical systems are discussed.

  15. An Innovative Approach for Decreasing Fall Trauma Admissions from Geriatric Living Facilities: Preliminary Investigation.

    PubMed

    Evans, Tracy; Gross, Brian; Rittenhouse, Katelyn; Harnish, Carissa; Vellucci, Ashley; Bupp, Katherine; Horst, Michael; Miller, Jo Ann; Baier, Ron; Chandler, Roxanne; Rogers, Frederick B

    2015-12-01

    Geriatric living facilities have been associated with a high rate of falls. We sought to develop an innovative intervention approach targeting geriatric living facilities that would reduce geriatric fall admissions to our Level II trauma center. In 2011, a Trauma Prevention Taskforce visited 5 of 28 local geriatric living facilities to present a fall prevention protocol composed of three sections: fall education, risk factor identification, and fall prevention strategies. To determine the impact of the intervention, the trauma registry was queried for all geriatric fall admissions attributed to patients living at local geriatric living facilities. The fall admission rate (total fall admissions/total beds) of the pre-intervention period (2010-2011) was compared with that of the postintervention period (2012-2013) at the 5 intervention and 23 control facilities. A P value < 0.05 was considered statistically significant. From 2010 to 2013, there were 487 fall admissions attributed to local geriatric living facilities (intervention: 179 fall admissions; control: 308 fall admissions). The unadjusted fall rate decreased at intervention facilities from 8.9 fall admissions/bed pre-intervention to 8.1 fall admissions/bed postintervention, whereas fall admission rates increased at control sites from 5.9 to 7.7 fall admissions/bed during the same period [control/intervention odds ratio (OR), 95% confidence interval (CI) = 1.32, 1.05-1.67; period OR, 95%CI = 1.55, 1.18-2.04, P = 0.002; interaction of control/intervention group and period OR 95% CI = 0.68, 0.46-1.00, P = 0.047]. An aggressive intervention program targeting high-risk geriatric living facilities resulted in a statistically significant decrease in geriatric fall admissions to our Level II trauma center.

  16. An Analytical Dynamics Approach to the Control of Mechanical Systems

    NASA Astrophysics Data System (ADS)

    Mylapilli, Harshavardhan

    A new and novel approach to the control of nonlinear mechanical systems is presented in this study. The approach is inspired by recent results in analytical dynamics that deal with the theory of constrained motion. The control requirements on the dynamical system are viewed from an analytical dynamics perspective and the theory of constrained motion is used to recast these control requirements as constraints on the dynamical system. Explicit closed form expressions for the generalized nonlinear control forces are obtained by using the fundamental equation of mechanics. The control so obtained is optimal at each instant of time and causes the constraints to be exactly satisfied. No linearizations and/or approximations of the nonlinear dynamical system are made, and no a priori structure is imposed on the nature of nonlinear controller. Three examples dealing with highly nonlinear complex dynamical systems that are chosen from diverse areas of discrete and continuum mechanics are presented to demonstrate the control approach. The first example deals with the energy control of underactuated inhomogeneous nonlinear lattices (or chains), the second example deals with the synchronization of the motion of multiple coupled slave gyros with that of a master gyro, and the final example deals with the control of incompressible hyperelastic rubber-like thin cantilever beams. Numerical simulations accompanying these examples show the ease, simplicity and the efficacy with which the control methodology can be applied and the accuracy with which the desired control objectives can be met.

  17. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  18. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  19. 38 CFR 23.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Admission. 23.300 Section 23.300 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 23.300 Admission. (a) General....

  20. 18 CFR 1317.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Admission. 1317.300 Section 1317.300 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.300 Admission. (a) General....

  1. 36 CFR 1211.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Admission. 1211.300 Section 1211.300 Parks, Forests, and Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION GENERAL RULES... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1211.300 Admission. (a) General....

  2. An Economic Model for Selective Admissions

    ERIC Educational Resources Information Center

    Haglund, Alma

    1978-01-01

    The author presents an economic model for selective admissions to postsecondary nursing programs. Primary determinants of the admissions model are employment needs, availability of educational resources, and personal resources (ability and learning potential). As there are more applicants than resources, selective admission practices are…

  3. 17 CFR 12.33 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... REPARATIONS Discovery § 12.33 Admissions. (a) Request for admissions. Any party may, within the time permitted... truth of any matters set forth in the request that relate to statements or opinions of fact or of the...) Reply. Each matter of which an admission is requested shall be separately set forth. The matter...

  4. Admission to Medical Education in Ten Countries.

    ERIC Educational Resources Information Center

    Burn, Barbara B., Ed.

    As part of a study of access and admission to higher education in Germany and the United States, a group of papers on medical admissions in various countries was commissioned. The papers presented in this book reveal wide differences in admissions policies and procedures. Barbara Burn examines some of the major issues in a foreword: representation…

  5. The Journal of College Admission Ethics Series.

    ERIC Educational Resources Information Center

    Loveland, Elaina C., Ed.; Raynor, Joyce, Ed.

    This book is the first significant body of literature on ethics in college admission published by the National Association for College Admission Counseling. The series is a select compilation of articles on ethics published in the Journal of College Admission in 1998 and 1999. The book is a source of information for the beginning and experienced…

  6. Reducing admissions for people with diabetes.

    PubMed

    Allan, Belinda

    Reversing the rise in emergency hospital admissions is an NHS priority. These admissions impact on elective capacity and waiting times and are unsustainable. The risk of hospitalisation for people with diabetes is almost twice that for others. Commissioners need to address admissions associated with diabetes and new guidance offers best-practice solutions.

  7. The Role of Noncognitive Assessment in Admissions

    ERIC Educational Resources Information Center

    Hoerle, Heather

    2014-01-01

    Confident that understanding and employing new approaches to assessment is a top priority for admissions professionals, the Secondary School Admission Test Board (SSATB) recently launched a Think Tank on the Future of Admission Assessment, with a two-year timeline and a charge to educate its membership and inspire greater innovation in admissions…

  8. Merit and Competition in Selective College Admissions

    ERIC Educational Resources Information Center

    Killgore, Leslie

    2009-01-01

    Using interview data from 34 admissions officers at 17 elite colleges, this paper compares two perspectives shaping admissions policy. Admissions officers apply a "merit" perspective that relies on indicators of student academic and nonacademic achievement. They also employ a "competition" perspective that evaluates student characteristics…

  9. Toward a Sociology of Law School Admissions.

    ERIC Educational Resources Information Center

    Erlanger, Howard S.

    1984-01-01

    The law school admission process plays a major role in determining the social class origins and ethnic composition of the bar, and perhaps also the nonlegal skills lawyers will have. Research is incomplete; consideration of admission criteria, the composition and processes of admissions committees, and applicant self-selection is advisable. (MSE)

  10. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  11. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission,...

  12. 10 CFR 1042.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... ENERGY (GENERAL PROVISIONS) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1042.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission,...

  13. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  14. 29 CFR 36.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 36.300 Admission. (a) General. No person shall, on the basis of sex, be denied admission, or...

  15. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  16. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  17. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  18. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  19. 7 CFR 501.2 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Admission. 501.2 Section 501.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON U.S. MEAT ANIMAL RESEARCH CENTER, CLAY CENTER, NEBRASKA § 501.2 Admission. Admission to...

  20. The Evolution of College Admission Requirements

    ERIC Educational Resources Information Center

    Beale, Andrew V.

    2012-01-01

    The development of college admissions requirements during the seventeenth and eighteenth centuries was basically the story of the admission policies and practices at Harvard College. Candidates for admission were examined on their ability to read and translate Latin and Greek, and a careful check was made of their character and background. With…

  1. Applying Workspace Limitations in a Velocity-Controlled Robotic Mechanism

    NASA Technical Reports Server (NTRS)

    Abdallah, Muhammad E. (Inventor); Hargrave, Brian (Inventor); Platt, Robert J., Jr. (Inventor)

    2014-01-01

    A robotic system includes a robotic mechanism responsive to velocity control signals, and a permissible workspace defined by a convex-polygon boundary. A host machine determines a position of a reference point on the mechanism with respect to the boundary, and includes an algorithm for enforcing the boundary by automatically shaping the velocity control signals as a function of the position, thereby providing smooth and unperturbed operation of the mechanism along the edges and corners of the boundary. The algorithm is suited for application with higher speeds and/or external forces. A host machine includes an algorithm for enforcing the boundary by shaping the velocity control signals as a function of the reference point position, and a hardware module for executing the algorithm. A method for enforcing the convex-polygon boundary is also provided that shapes a velocity control signal via a host machine as a function of the reference point position.

  2. Equivalences between nonuniform exponential dichotomy and admissibility

    NASA Astrophysics Data System (ADS)

    Zhou, Linfeng; Lu, Kening; Zhang, Weinian

    2017-01-01

    Relationship between exponential dichotomies and admissibility of function classes is a significant problem for hyperbolic dynamical systems. It was proved that a nonuniform exponential dichotomy implies several admissible pairs of function classes and conversely some admissible pairs were found to imply a nonuniform exponential dichotomy. In this paper we find an appropriate admissible pair of classes of Lyapunov bounded functions which is equivalent to the existence of nonuniform exponential dichotomy on half-lines R± separately, on both half-lines R± simultaneously, and on the whole line R. Additionally, the maximal admissibility is proved in the case on both half-lines R± simultaneously.

  3. Study of Neuro-Controllers for Motion Control Systems with Distributed Mechanical Flexibility.

    DTIC Science & Technology

    2007-11-02

    Control of motion systems involving distributed mechanical flexibility is studied using artificial neural networks . Infinite dimensional nature of...into consideration. Three different neuro controller architectures are studied: 1) Hopfield nets for modal parameter estimation and real time solution of...neural network controller for high precision motion control. Thre results are summarized and details are presented in refereed publications.

  4. Effects of a pharmacist-led structured medication review in primary care on drug-related problems and hospital admission rates: a randomized controlled trial

    PubMed Central

    Elfsson, Birgitta; Danielsson, Birgitta; Midlöv, Patrik; Hasselström, Jan

    2014-01-01

    Abstract Objective. To determine whether a pharmacist-led medications review in primary care reduces the number of drugs and the number of drug-related problems. Design. Prospective randomized controlled trial. Setting. Liljeholmen Primary Care Centre, Stockholm, Sweden. Subjects. 209 patients aged ≥ 65 years with five or more different medications. Intervention. Patients answered a questionnaire regarding medications. The pharmacist reviewed all medications (prescription, non-prescription, and herbal) regarding recommendations and renal impairment, giving advice to patients and GPs. Each patient met the pharmacist before seeing their GP. Control patients received their usual care. Main outcome measures. Drug-related problems and number of drugs. Secondary outcomes included health care utilization and self-rated health during 12 months of follow-up. Results. No significant difference was seen when comparing change in drug-related problems between the groups. However, a significant decrease in drug-related problems was observed in the intervention group (from 1.73 per patient at baseline to 1.31 at follow-up, p < 0.05). The change in number of drugs was more pronounced in the intervention group (p < 0.046). Intervention group patients were not admitted to hospital on fewer occasions or for fewer days, and there was no significant difference between the two groups regarding utilization of primary care during follow-up. Self-rated health remained unchanged in the intervention group, whereas a drop (p < 0.02) was reported in the control group. This resulted in a significant difference in change in self-rated health between the groups (p < 0.047). Conclusions. The addition of a skilled pharmacist to the primary care team may contribute to reductions in numbers of drugs and maintenance of self-rated health in elderly patients with polypharmacy. PMID:25347723

  5. The JPL telerobotic Manipulator Control and Mechanization (MCM) subsystem

    NASA Technical Reports Server (NTRS)

    Hayati, Samad; Lee, Thomas S.; Tso, Kam; Backes, Paul; Kan, Edwin; Lloyd, J.

    1989-01-01

    The Manipulator Control and Mechanization (MCM) subsystem of the telerobot system provides the real-time control of the robot manipulators in autonomous and teleoperated modes and real time input/output for a variety of sensors and actuators. Substantial hardware and software are included in this subsystem which interfaces in the hierarchy of the telerobot system with the other subsystems. The other subsystems are: run time control, task planning and reasoning, sensing and perception, and operator control subsystem. The architecture of the MCM subsystem, its capabilities, and details of various hardware and software elements are described. Important improvements in the MCM subsystem over the first version are: dual arm coordinated trajectory generation and control, addition of integrated teleoperation, shared control capability, replacement of the ultimate controllers with motor controllers, and substantial increase in real time processing capability.

  6. Pressure versus volume controlled modes in invasive mechanical ventilation.

    PubMed

    Garnero, A J; Abbona, H; Gordo-Vidal, F; Hermosa-Gelbard, C

    2013-05-01

    The first generation of mechanical ventilators were controlled and cycled by pressure. Unfortunately, they did not allow control of the delivered tidal volume under changes in the dynamics of the respiratory system. This led to a second generation of ventilators that allowed volume control, hence favoring the ventilatory strategy based on normalization of the arterial gases. Studies conducted in the 1980s which related lung injury to the high ventilator pressures utilized while treating acute respiratory distress syndrome patients renewed interest in pressure-controlled mechanical ventilation. In addition, new evidence became available, leading to the development of pulmonary protective strategies aiming at preventing the progression of ventilator-induced lung injury. This review provides a detailed description of the control of pressure or volume using certain ventilatory modes, and offers a general view of their advantages and disadvantages, based on the latest available evidence.

  7. Characteristics of Mechanical Pumps and Energy Saving Automatic Control System

    NASA Astrophysics Data System (ADS)

    Ueda, Tadashi; Uchida, Yoshiyuki; Shingu, Hiroyasu

    In the 21st century, global warming has become a very serious ecological problem. It is necessary to prevent global warming from increasing the greenhouse effect gas such as carbon dioxide. A new energy saving technique using mechanical pump system is proposed as a solution to this problem. The pump carrying the water, which is the heat source, for the air conditioner has an effect on energy saving by using effective automatic control. Since there is a lack of knowledge related to mechanical pump, effective automatic control systems combined with some pumps are implemented only in a few buildings. In this paper, the machine characteristics of a mechanical pump and a system design combined with some pumps are applied to a decrease in energy consumption. Based on the characteristics of the pump, the automatic control techniques are constant discharged pressure control technique, estimated end pressure control technique and real end pressure control technique. In this paper, the estimated end pressure control technique is recommended as a result of testing the automatic control system combined with the pumps. Also, improvement in conditions of the pump is proposed as a new energy saving technique.

  8. Control mechanism of double-rotator-structure ternary optical computer

    NASA Astrophysics Data System (ADS)

    Kai, SONG; Liping, YAN

    2017-03-01

    Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

  9. Geometric control of quantum mechanical and nonlinear classical systems

    NASA Astrophysics Data System (ADS)

    Nelson, Richard Joseph

    1999-10-01

    Geometric control refers to the judicious use of the non- commuting nature of inputs and natural dynamics as the basis for control. The last few decades in control system theory have seen the application of differential geometry in proving several important properties of systems, including controllability and observability. Until recently, however, the results of this mathematical geometry have rarely been used as the basis for designing and implementing an actual controller. This thesis demonstrates the application of a judicious selection of inputs, so that if the system is proven to be controllable using geometric methods, one can design input sequences using the same geometry. A demonstration of this method is shown in simulating the attitude control of a satellite: a highly non-linear, non- holonomic control problem. Although not a practical method for large re-orientations of a typical satellite, the approach can be applied to other nonlinear systems. The method is also applied to the closed-loop performance of a quantum mechanical system to demonstrate the feasibility of coherent quantum feedback-something impossible using a conventional controller. Finally, the method is applied in the open-loop control of a quantum mechanical system: in this case, the creation of Greenberger-Horne-Zeilinger correlations among the nuclei of an ensemble of alanine molecules in a nuclear magnetic resonance spectrometer. In each case, the data demonstrate the usefulness of a geometric approach to control. In addition to demonstrations of geometric control in practice, the quantum mechanical experiments also demonstrate for the first time peculiar quantum correlations, including GHZ correlations, that have no classical analog. The quantum experiments further establish nuclear magnetic resonance as a viable and accessible testbed of quantum predictions and processes. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax

  10. Growth Control and Disease Mechanisms in Computational Embryogeny

    NASA Technical Reports Server (NTRS)

    Shapiro, Andrew A.; Yogev, Or; Antonsson, Erik K.

    2008-01-01

    This paper presents novel approach to applying growth control and diseases mechanisms in computational embryogeny. Our method, which mimics fundamental processes from biology, enables individuals to reach maturity in a controlled process through a stochastic environment. Three different mechanisms were implemented; disease mechanisms, gene suppression, and thermodynamic balancing. This approach was integrated as part of a structural evolutionary model. The model evolved continuum 3-D structures which support an external load. By using these mechanisms we were able to evolve individuals that reached a fixed size limit through the growth process. The growth process was an integral part of the complete development process. The size of the individuals was determined purely by the evolutionary process where different individuals matured to different sizes. Individuals which evolved with these characteristics have been found to be very robust for supporting a wide range of external loads.

  11. Rock mechanics. Superplastic nanofibrous slip zones control seismogenic fault friction.

    PubMed

    Verberne, Berend A; Plümper, Oliver; de Winter, D A Matthijs; Spiers, Christopher J

    2014-12-12

    Understanding the internal mechanisms controlling fault friction is crucial for understanding seismogenic slip on active faults. Displacement in such fault zones is frequently localized on highly reflective (mirrorlike) slip surfaces, coated with thin films of nanogranular fault rock. We show that mirror-slip surfaces developed in experimentally simulated calcite faults consist of aligned nanogranular chains or fibers that are ductile at room conditions. These microstructures and associated frictional data suggest a fault-slip mechanism resembling classical Ashby-Verrall superplasticity, capable of producing unstable fault slip. Diffusive mass transfer in nanocrystalline calcite gouge is shown to be fast enough for this mechanism to control seismogenesis in limestone terrains. With nanogranular fault surfaces becoming increasingly recognized in crustal faults, the proposed mechanism may be generally relevant to crustal seismogenesis.

  12. Mechanisms for control of biological electron transfer reactions

    PubMed Central

    Williamson, Heather R.; Dow, Brian A.; Davidson, Victor L.

    2014-01-01

    Electron transfer (ET) through and between proteins is a fundamental biological process. The rates and mechanisms of these ET reactions are controlled by the proteins in which the redox centers that donate and accept electrons reside. The protein influences the magnitudes of the ET parameters, the electronic coupling and reorganization energy that are associated with the ET reaction. The protein can regulate the rates of the ET reaction by requiring reaction steps to optimize the system for ET, leading to kinetic mechanisms of gated or coupled ET. Amino acid residues in the segment of the protein through which long range ET occurs can also modulate the ET rate by serving as staging points for hopping mechanisms of ET. Specific examples are presented to illustrate these mechanisms by which proteins control rates of ET reactions. PMID:25085775

  13. Development of Ti-Nb-Zr alloys with high elastic admissible strain for temporary orthopedic devices.

    PubMed

    Ozan, Sertan; Lin, Jixing; Li, Yuncang; Ipek, Rasim; Wen, Cuie

    2015-07-01

    A new series of beta Ti-Nb-Zr (TNZ) alloys with considerable plastic deformation ability during compression test, high elastic admissible strain, and excellent cytocompatibility have been developed for removable bone tissue implant applications. TNZ alloys with nominal compositions of Ti-34Nb-25Zr, Ti-30Nb-32Zr, Ti-28Nb-35.4Zr and Ti-24.8Nb-40.7Zr (wt.% hereafter) were fabricated using the cold-crucible levitation technique, and the effects of alloying element content on their microstructures, mechanical properties (tensile strength, yield strength, compressive yield strength, Young's modulus, elastic energy, toughness, and micro-hardness), and cytocompatibilities were investigated and compared. Microstructural examinations revealed that the TNZ alloys consisted of β phase. The alloy samples displayed excellent ductility with no cracking, or fracturing during compression tests. Their tensile strength, Young's modulus, elongation at rupture, and elastic admissible strain were measured in the ranges of 704-839 MPa, 62-65 GPa, 9.9-14.8% and 1.08-1.31%, respectively. The tensile strength, Young's modulus and elongation at rupture of the Ti-34Nb-25Zr alloy were measured as 839 ± 31.8 MPa, 62 ± 3.6 GPa, and 14.8 ± 1.6%, respectively; this alloy exhibited the elastic admissible strain of approximately 1.31%. Cytocompatibility tests indicated that the cell viability ratios (CVR) of the alloys are greater than those of the control group; thus the TNZ alloys possess excellent cytocompatibility.

  14. COAXIAL CONTROL ROD DRIVE MECHANISM FOR NEUTRONIC REACTORS

    DOEpatents

    Fox, R.J.; Oakes, L.C.

    1959-04-14

    A drive mechanism is presented for the control rod or a nuclear reactor. In this device the control rod is coupled to a drive shaft which extends coaxially through the rotor of an electric motor for relative rotation with respect thereto. A gear reduction mehanism is coupled between the rotor and the drive shaft to convert the rotary motion of the motor into linear motion of the shaft with a comparatively great reduction in speed, thereby providing relatively glow linear movement of the shaft and control rod for control purposes.

  15. Multisensory Mechanisms of Gaze Stabilization and Flight Control

    DTIC Science & Technology

    2008-12-17

    Multisensory mechanisms of gaze stabilization and flight control 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5d. TASK NUMBER 6. AUTHOR(S...email: h.g.krapp@imperial.ac.uk Imperial College South Kensington Campus London SW7 2AZ “ Multisensory Mechanisms of Gaze... Multisensory Integration, and Efference Copies in Behaving Animals 2.5 State-dependent Processing in LPTCs 2.6 Characterization of Head Movements in the

  16. Mechanically implementable accommodation matrices for passive force control

    SciTech Connect

    Goswami, A.; Peshkin, M.

    1999-08-01

    Robot force control implemented by means of passive mechanical devices has inherent advantages over active implementations with regard to stability, response rapidity, and physical robustness. The class of devices considered in this paper consists of a Stewart platform-type mechanism interconnected with a network of adjustable mechanical elements such as springs and dampers. The control law repertoire of such a device, imagined as a robot wrist, is given by the range of admittance matrices that it may be programmed to possess. This paper focuses on wrists incorporating damper networks for which the admittance matrices reduce to accommodation or inverse-damping matrices. The authors show that a hydraulic network of fully adjustable damper elements may attain any diagonally dominant accommodation matrix. They describe the technique of selecting the individual damping coefficients to design a desired matrix. They identify the set of dominant matrices as a polyhedral convex cone in the space of matrix entries, and show that each dominant matrix can be composed of a positive linear combination of a fixed set of basis matrices. The overall wrist-accommodation matrix is obtained by projecting the accommodation matrix of the damper network through the wrist kinematics. The linear combination of the dominant basis matrices projected through the wrist kinematics generates the entire space of mechanically implementable force-control laws. The authors quantify the versatility of mechanically implementable force-control laws by comparing this space to the space of all matrices.

  17. Tuberculosis in hospitalized patients: clinical characteristics of patients receiving treatment within the first 24 h after admission*

    PubMed Central

    Silva, Denise Rossato; da Silva, Larissa Pozzebon; Dalcin, Paulo de Tarso Roth

    2014-01-01

    Objective: To evaluate clinical characteristics and outcomes in patients hospitalized for tuberculosis, comparing those in whom tuberculosis treatment was started within the first 24 h after admission with those who did not. Methods: This was a retrospective cohort study involving new tuberculosis cases in patients aged ≥ 18 years who were hospitalized after seeking treatment in the emergency room. Results: We included 305 hospitalized patients, of whom 67 (22.0%) received tuberculosis treatment within the first 24 h after admission ( ≤24h group) and 238 (88.0%) did not (>24h group). Initiation of tuberculosis treatment within the first 24 h after admission was associated with being female (OR = 1.99; 95% CI: 1.06-3.74; p = 0.032) and with an AFB-positive spontaneous sputum smear (OR = 4.19; 95% CI: 1.94-9.00; p < 0.001). In the ≤24h and >24h groups, respectively, the ICU admission rate was 22.4% and 15.5% (p = 0.258); mechanical ventilation was used in 22.4% and 13.9% (p = 0.133); in-hospital mortality was 22.4% and 14.7% (p = 0.189); and a cure was achieved in 44.8% and 52.5% (p = 0.326). Conclusions: Although tuberculosis treatment was initiated promptly in a considerable proportion of the inpatients evaluated, the rates of in-hospital mortality, ICU admission, and mechanical ventilation use remained high. Strategies for the control of tuberculosis in primary care should consider that patients who seek medical attention at hospitals arrive too late and with advanced disease. It is therefore necessary to implement active surveillance measures in the community for earlier diagnosis and treatment. PMID:25029651

  18. A Study to Determine the Validity of the Nursing Admission Assessment (DA Form 3888/3888-1) as a Mechanism for Identifying the Presence of One or More Universal Indicators of the Need for Discharge Planning

    DTIC Science & Technology

    1987-08-01

    SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FED GROUP SUB3-GROUP ’Discharge Planning, Admission Assessment, Nursing...Assessment, Functional Assessment, Universal Indicators ,~~ 19, ABSTRACT (Continue on reverse if necessary and identify by block numaf) This project...further evaluation. The reverse side of DA Form 3888-1 contains the prob- lem list with expected outcomes and a section for recording 47 discharge

  19. Mechanical Response of DNA–Nanoparticle Crystals to Controlled Deformation

    PubMed Central

    2016-01-01

    The self-assembly of DNA-conjugated nanoparticles represents a promising avenue toward the design of engineered hierarchical materials. By using DNA to encode nanoscale interactions, macroscale crystals can be formed with mechanical properties that can, at least in principle, be tuned. Here we present in silico evidence that the mechanical response of these assemblies can indeed be controlled, and that subtle modifications of the linking DNA sequences can change the Young’s modulus from 97 kPa to 2.1 MPa. We rely on a detailed molecular model to quantify the energetics of DNA–nanoparticle assembly and demonstrate that the mechanical response is governed by entropic, rather than enthalpic, contributions and that the response of the entire network can be estimated from the elastic properties of an individual nanoparticle. The results here provide a first step toward the mechanical characterization of DNA–nanoparticle assemblies, and suggest the possibility of mechanical metamaterials constructed using DNA. PMID:27725959

  20. Active Control of Mixing and Combustion, from Mechanisms to Implementation

    NASA Astrophysics Data System (ADS)

    Ghoniem, Ahmed F.

    2001-11-01

    Implementation of active control in complex processes, of the type encountered in high Reynolds number mixing and combustion, is predicated upon the identification of the underlying mechanisms and the construction of reduced order models that capture their essential characteristics. The mechanisms of interest must be shown to be amenable to external actuations, allowing optimal control strategies to exploit the delicate interactions that lead to the desired outcome. Reduced order models are utilized in defining the form and requisite attributes of actuation, its relationship to the monitoring system and the relevant control algorithms embedded in a feedforward or a feedback loop. The talk will review recent work on active control of mixing in combustion devices in which strong shear zones concur with mixing, combustion stabilization and flame anchoring. The underlying mechanisms, e.g., stability of shear flows, formation/evolution of large vortical structures in separating and swirling flows, their mutual interactions with acoustic fields, flame fronts and chemical kinetics, etc., are discussed in light of their key roles in mixing, burning enhancement/suppression, and combustion instability. Subtle attributes of combustion mechanisms are used to suggest the requisite control strategies.

  1. Output feedback control of a mechanical system using magnetic levitation.

    PubMed

    Beltran-Carbajal, F; Valderrabano-Gonzalez, A; Rosas-Caro, J C; Favela-Contreras, A

    2015-07-01

    This paper presents an application of a nonlinear magnetic levitation system to the problem of efficient active control of mass-spring-damper mechanical systems. An output feedback control scheme is proposed for reference position trajectory tracking tasks on the flexible mechanical system. The electromagnetically actuated system is shown to be a differentially flat nonlinear system. An extended state estimation approach is also proposed to obtain estimates of velocity, acceleration and disturbance signals. The differential flatness structural property of the system is then employed for the synthesis of the controller and the signal estimation approach presented in this work. Some experimental and simulation results are included to show the efficient performance of the control approach and the effective estimation of the unknown signals.

  2. Design and control of a high precision drive mechanism

    NASA Astrophysics Data System (ADS)

    Pan, Bo; He, Yongqiang; Wang, Haowei; Zhang, Shuyang; Zhang, Donghua; Wei, Xiaorong; Jiang, Zhihong

    2017-01-01

    This paper summarizes the development of a high precision drive mechanism (HPDM) for space application, such as the directional antenna, the laser communication device, the mobile camera and other pointing mechanisms. In view of the great practical significance of high precision drive system, control technology for permanent magnet synchronous motor (PMSM) servo system is also studied and a PMSM servo controller is designed in this paper. And the software alignment was applied to the controller to eliminate the steady error of the optical encoder, which helps to realize the 1 arcsec (1σ) control precision. To assess its capabilities, the qualification environment testing including the thermal vacuum cycling testing, and the sinusoidal and random vibration were carried out. The testing results show that the performance of the HPDM is almost the same between the former and the end of each testing.

  3. Designing Crane Controls with applied Mechanical and Electrical Safety Features

    NASA Technical Reports Server (NTRS)

    Lytle, Bradford P.; Walczak, Thomas A.; Delgado, H. (Technical Monitor)

    2002-01-01

    The use of overhead traveling bridge cranes in many varied applications is common practice. In particular, the use of cranes in the nuclear, military, commercial, aerospace, and other industries can involve safety critical situations. Considerations for Human Injury or Casualty, Loss of Assets, Endangering the Environment, or Economic Reduction must be addressed. Traditionally, in order to achieve additional safety in these applications, mechanical systems have been augmented with a variety of devices. These devices assure that a mechanical component failure shall reduce the risk of a catastrophic loss of the correct and/or safe load carrying capability. ASME NOG-1-1998, (Rules for Construction of Overhead and Gantry Cranes, Top Running Bridge, and Multiple Girder), provides design standards for cranes in safety critical areas. Over and above the minimum safety requirements of todays design standards, users struggle with obtaining a higher degree of reliability through more precise functional specifications while attempting to provide "smart" safety systems. Electrical control systems also may be equipped with protective devices similar to the mechanical design features. Demands for improvement of the cranes "control system" is often recognized, but difficult to quantify for this traditionally "mechanically" oriented market. Finite details for each operation must be examined and understood. As an example, load drift (or small motions) at close tolerances can be unacceptable (and considered critical). To meet these high functional demands encoders and other devices are independently added to control systems to provide motion and velocity feedback to the control drive. This paper will examine the implementation of Programmable Electronic Systems (PES). PES is a term this paper will use to describe any control system utilizing any programmable electronic device such as Programmable Logic Controllers (PLC), or an Adjustable Frequency Drive (AID) 'smart' programmable

  4. Control Mechanism Strategies for Spin-Stabilized Projectiles

    DTIC Science & Technology

    2008-09-01

    maneuver footprint shape was dictated by the angle -of-fall and yaw of repose . Shallow angles -of-fall produced footprint ellipses, with a major axis...Magnus moments and yaw of repose . Adding a control mechanism such as fins to guide a spin- stabilized projectile further complicates the resulting...ratio), and the roll window over which the pulsed controller operated. The metrics of this analysis were the maneuver footprint, total angle of attack

  5. Mechanisms of active control for noise inside a vibrating cylinder

    NASA Technical Reports Server (NTRS)

    Lester, Harold C.; Fuller, Chris R.

    1987-01-01

    The active control of propeller-induced noise fields inside a flexible cylinder is studied with attention given to the noise reduction mechanisms inherent in the present coupled acoustic shell model. The active noise control model consists of an infinitely long aluminum cylinder with a radius of 0.4 m and a thickness of 0.001 m. Pressure maps are shown when the two external sources are driven in-phase at a frequency corresponding to Omega = 0.22.

  6. Fluid Mechanics of Wing Adaptation for Separation Control

    NASA Technical Reports Server (NTRS)

    Chandrasekhara, M. S.; Wilder, M. C.; Carr, L. W.; Davis, Sanford S. (Technical Monitor)

    1997-01-01

    The unsteady fluid mechanics associated with use of a dynamically deforming leading edge airfoil for achieving compressible flow separation control has been experimentally studied. Changing the leading edge curvature at rapid rates dramatically alters the flow vorticity dynamics which is responsible for the many effects observed in the flow.

  7. Quality Control Mechanisms for Appraising the Teaching Labour Force.

    ERIC Educational Resources Information Center

    Tam, Peter Tim-Kui

    1992-01-01

    To maintain teacher quality, the use of assessment mechanisms and instruments are necessary. Suggests a general teacher evaluation framework ranging from preservice teacher education through professional development and peer-controlled certification. Argues that valid, fair, and reliable methods of teacher evaluation require adequate financial…

  8. Three degree of freedom translational axis hand controller mechanism

    NASA Technical Reports Server (NTRS)

    Menahem, Israel (Inventor); Bacon, James (Inventor)

    1993-01-01

    A hand controller which includes a hand grip having therein a mechanism for allowing truly linear motion along at least two axes by modifying a four-bar linkage with a second four-bar linkage to counteract any rotational motion that would otherwise occur.

  9. Quasivelocities and Optimal Control for underactuated Mechanical Systems

    NASA Astrophysics Data System (ADS)

    Colombo, L.; de Diego, D. Martín

    2010-07-01

    This paper is concerned with the application of the theory of quasivelocities for optimal control for underactuated mechanical systems. Using this theory, we convert the original problem in a variational second-order lagrangian system subjected to constraints. The equations of motion are geometrically derived using an adaptation of the classical Skinner and Rusk formalism.

  10. 6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ACCUMULATOR TANK WHICH STORE AIR PRESSURE TO OPEN GATES AND GET GENERATOR STARTED. LARGE TANK AT RIGHT IS THE MAIN GUARD VALVE FOR THE GENERATOR - Los Angeles Aqueduct, Haiwee Power Plant, Los Angeles, Los Angeles County, CA

  11. Control of mechanical systems with rolling contacts: Applications to robotics

    NASA Astrophysics Data System (ADS)

    Sarkar, Nilanjan

    1993-01-01

    The problems of modeling and control of mechanical dynamic systems subject to rolling contacts are investigated. There are two important theoretical contributions in this dissertation. First, contact kinematic relationships up to second order are developed for two rigid bodies in point contact. These equations relate gross rigid body motion to the changes in the positions of the points of contact. Second, a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints is proposed. The basic approach is to extend the state-space to include, in the addition to the generalized coordinates and velocities, contact coordinates which describe the displacements of the contact points and their derivatives. This redundant state-space formulation provides a convenient way to specify output equations to control contact motion. The control problem is formulated as an affine nonlinear problem and a differential-geometric, control-theoretic approach is used to decouple and linearize such systems. It is shown that such a system, even though not input-state linearizable, is input-output linearizable. Further, the zero dynamics of such a system is shown to be Lagrange stable. The proposed methodology is applied to three different robotic systems: (1) wheeled mobile robots; (2) two arms manipulating an object with rolling contact between each arm and the object; and (3) a single robot arm maintaining controlled contact against a moving environment. In each case, a nonlinear controller is designed to achieve the desired performances. For mobile robots, a new control algorithm called dynamic path following is proposed and shown to be quite effective and robust. In the context of two arm manipulation, grasp adaptation through the control of contact motion is demonstrated. Maintaining rolling contact with a moving surface is formulated as an acatastatic system. The proposed scheme involves simultaneously controlling interaction forces as

  12. Mechanisms and Control of Silk-based Electrospinning

    PubMed Central

    Zhang, Feng; Zuo, Baoqi; Fan, Zhihai; Xie, Zonggang; Lu, Qiang; Zhang, Xueguang; Kaplan, David L.

    2012-01-01

    Silk fibroin (SF) nanofibers, formed through electrospinning, have attractive utility in regenerative medicine due to the biocompatibility, mechanical properties and tailorable degradability. The mechanism of SF electrospun nanofiber formation was studied to gain new insight into the formation and control of nanofibers. SF electrospinning solutions with different nanostructures (nanospheres or nanofilaments) were prepared by controlling the drying process during the preparation of regenerated SF films. Compared to SF nanospheres in solution, SF nanofilaments had better spinnability with lower viscosity when the concentration of silk protein was below 10%, indicating a critical role for SF morphology, and in particular, nanostructures for the formation of electrospun fibers. More interesting, the diameter of electrospun fibers gradually increased from 50 nm to 300 nm as the increase in concentration of SF nanofilaments in the solution from 6% to 12%, implying size control by simply adjusting SF nanostructure and concentration. Aside from process parameters investigated in previous studies, such as SF concentration, viscosity and electrical potential, the present mechanism emphasizes significant influence of SF nanostructure on spinnability and diameter control of SF electrospun fibers, providing a controllable option for the preparation of silk-based electrospun scaffolds for biomaterials, drug delivery and tissue engineering needs. PMID:22300335

  13. Active vibration control using mechanical and electrical analogies

    NASA Astrophysics Data System (ADS)

    Torres-Perez, A.; Hassan, A.; Kaczmarczyk, S.; Picton, P.

    2016-05-01

    Mechanical-electrical analogous circuit models are widely used in electromechanical system design as they represent the function of a coupled electrical and mechanical system using an equivalent electrical system. This research uses electrical circuits to establish a discussion of simple active vibration control principles using two scenarios: an active vibration isolation system and an active dynamic vibration absorber (DVA) using a voice coil motor (VCM) actuator. Active control laws such as gain scheduling are intuitively explained using circuit analysis techniques. Active vibration control approaches are typically constraint by electrical power requirements. The electrical analogous is a fast approach for specifying power requirements on the experimental test platform which is based on a vibration shaker that provides the based excitation required for the single Degree- of-Freedom (1DoF) vibration model under study.

  14. Robust control of multi-jointed arm with a decentralized autonomous control mechanism

    NASA Technical Reports Server (NTRS)

    Kimura, Shinichi; Miyazaki, Ken; Suzuki, Yoshiaki

    1994-01-01

    A decentralized autonomous control mechanism applied to the control of three dimensional manipulators and its robustness to partial damage was assessed by computer simulation. Decentralized control structures are believed to be quite robust to time delay between the operator and the target system. A 10-jointed manipulator based on our control mechanism was able to continue its positioning task in three-dimensional space without revision of the control program, even after some of its joints were damaged. These results suggest that this control mechanism can be effectively applied to space telerobots, which are associated with serious time delay between the operator and the target system, and which cannot be easily repaired after being partially damaged.

  15. Mechanisms in environmentally assisted one-photon phase control

    NASA Astrophysics Data System (ADS)

    Pachón, Leonardo A.; Brumer, Paul

    2013-10-01

    The ability of an environment to assist in one-photon phase control relies upon entanglement between the system and bath and on the breaking of the time reversal symmetry. Here, one-photon phase control is examined analytically and numerically in a model system, allowing an analysis of the relative strength of these contributions. Further, the significant role of non-Markovian dynamics and of moderate system-bath coupling in enhancing one-photon phase control is demonstrated, and an explicit role for quantum mechanics is noted in the existence of initial non-zero stationary coherences. Finally, desirable conditions are shown to be required to observe such environmentally assisted control, since the system will naturally equilibrate with its environment at longer times, ultimately resulting in the loss of phase control.

  16. Control of autoresonance in mechanical and physical models

    NASA Astrophysics Data System (ADS)

    Kovaleva, A.

    2017-03-01

    Autoresonant energy transfer has been considered as one of the most effective methods of excitation and control of high-energy oscillations for a broad range of physical and engineering systems. Nonlinear time-invariant feedback control provides effective self-tuning and self-adaptation mechanisms targeted at preserving resonance oscillations under variations of the system parameters but its implementation may become extremely complicated. A large class of systems can avoid nonlinear feedback, still producing the required state due to time-variant feed-forward frequency control. This type of control in oscillator arrays employs an intrinsic property of a nonlinear oscillator to vary both its amplitude and the frequency when the driving frequency changes. This paper presents a survey of recently published and new results studying possibilities and limitations of time-variant frequency control in nonlinear oscillator arrays. This article is part of the themed issue 'Horizons of cybernetical physics'.

  17. 45 CFR 2555.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false Admission. 2555.300 Section 2555.300 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 2555.300 Admission. (a) General. No..., by any recipient to which §§ 2555.300 through 2555.310 apply, except as provided in §§ 2555.225...

  18. 6 CFR 17.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Admission. 17.300 Section 17.300 Domestic... in Admission and Recruitment Prohibited § 17.300 Admission. (a) General. No person shall, on the... which §§ 17.300 through 17.310 apply, except as provided in §§ 17.225 and 17.230. (b)...

  19. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Admission. 5.300 Section 5.300... in Admission and Recruitment Prohibited § 5.300 Admission. (a) General. No person shall, on the basis... which §§ 5.300 through §§ 5.310 apply, except as provided in §§ 5.225 and 5.230. (b)...

  20. 15 CFR 8a.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Admission. 8a.300 Section 8a.300... in Admission and Recruitment Prohibited § 8a.300 Admission. (a) General. No person shall, on the... which §§ 8a.300 through §§ 8a.310 apply, except as provided in §§ 8a.225 and §§ 8a.230. (b)...

  1. 45 CFR 2555.300 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Admission. 2555.300 Section 2555.300 Public... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 2555.300 Admission. (a) General. No..., by any recipient to which §§ 2555.300 through 2555.310 apply, except as provided in §§ 2555.225...

  2. 14 CFR 1253.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Admission. 1253.300 Section 1253.300... in Admission and Recruitment Prohibited § 1253.300 Admission. (a) General. No person shall, on the... which §§ 1253.300 through §§ 1253.310 apply, except as provided in §§ 1253.225 and §§ 1253.230....

  3. A general framework for robust control in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Bewley, Thomas R.; Temam, Roger; Ziane, Mohammed

    2000-04-01

    The application of optimal control theory to complex problems in fluid mechanics has proven to be quite effective when complete state information from high-resolution numerical simulations is available [P. Moin, T.R. Bewley, Appl. Mech. Rev., Part 2 47 (6) (1994) S3-S13; T.R. Bewley, P. Moin, R. Temam, J. Fluid Mech. (1999), submitted for publication]. In this approach, an iterative optimization algorithm based on the repeated computation of an adjoint field is used to optimize the controls for finite-horizon nonlinear flow problems [F. Abergel, R. Temam, Theoret. Comput. Fluid Dyn. 1 (1990) 303-325]. In order to extend this infinite-dimensional optimization approach to control externally disturbed flows in which the controls must be determined based on limited noisy flow measurements alone, it is necessary that the controls computed be insensitive to both state disturbances and measurement noise. For this reason, robust control theory, a generalization of optimal control theory, has been examined as a technique by which effective control algorithms which are insensitive to a broad class of external disturbances may be developed for a wide variety of infinite-dimensional linear and nonlinear problems in fluid mechanics. An aim of the present paper is to put such algorithms into a rigorous mathematical framework, for it cannot be assumed at the outset that a solution to the infinite-dimensional robust control problem even exists. In this paper, conditions on the initial data, the parameters in the cost functional, and the regularity of the problem are established such that existence and uniqueness of the solution to the robust control problem can be proven. Both linear and nonlinear problems are treated, and the 2D and 3D nonlinear cases are treated separately in order to get the best possible estimates. Several generalizations are discussed and an appropriate numerical method is proposed.

  4. Temporal variation in major trauma admissions

    PubMed Central

    Kieffer, WKM; Michalik, DV; Gallagher, K; McFadyen, I; Bernard, J; Rogers, BA

    2016-01-01

    Introduction Trauma is a significant cause of morbidity and mortality in the UK. Since the inception of the trauma networks, little is known of the temporal pattern of trauma admissions. Methods Trauma Audit and Research Network data for 1 April 2011 to 31 March 2013 were collated from two large major trauma centres (MTCs) in the South East of England: Brighton and Sussex University Hospitals NHS Trust (BSUH) and St George's University Hospitals NHS Foundation Trust (SGU). The number of admissions and the injury severity score by time of admission, by weekdays versus weekend and by month/season were analysed. Results There were 1,223 admissions at BSUH and 1,241 at SGU. There was significant variation by time of admission; there were more admissions in the afternoons (BSUH p<0.001) and evenings (SGU p<0.001). There were proportionally more admissions at the weekends than on weekdays (BSUH p<0.001, SGU p=0.028). There was significant seasonal variation in admissions at BSUH (p<0.001) with more admissions in summer and autumn. No significant seasonal variation was observed at SGU (p=0.543). Conclusions The temporal patterns observed were different for each MTC with important implications for resource planning of trauma care. This study identified differing needs for different MTCs and resource planning should be individualised to the network. PMID:26741676

  5. Flow around a semicircular cylinder with passive flow control mechanisms

    NASA Astrophysics Data System (ADS)

    Hamed, A. M.; Vega, J.; Liu, B.; Chamorro, L. P.

    2017-03-01

    Wind tunnel experiments were performed to study the effect of passive flow control strategies on the wake and drag of a semicircular cylinder of infinite aspect ratio. High-resolution planar particle image velocimetry was used to obtain flow statistics around the semicircular cylinder at Reynolds number Re≈ 3.2× 10^4 based on the cylinder diameter. The control mechanisms under consideration include rigid flaps of various lengths placed at the edges of the structure and a small slot along the symmetry plane of the cylinder. Mean velocity fields reveal the distinctive effects of each passive mechanism on the flow, such as velocity recovery, size of the recirculation bubble and location of the reattachment point. The distributions of turbulence kinetic energy and kinematic shear stress show the modulation of each passive control mechanism on the wake, including the onset and location of the maximum turbulence levels. Instantaneous and mean fields of swirling strength further highlight the role of the passive mechanisms in the vortex dynamics. Drag coefficient for the various cases was estimated indirectly from the flow measurements using a momentum balance. This approach shows that long flaps and slot were able to reduce drag with respect to the base case. The rigid flaps with length coincident with the diameter of the cylinder offered the best performance with drag reduction of ˜25%.

  6. Adaptive mechanism-based congestion control for networked systems

    NASA Astrophysics Data System (ADS)

    Liu, Zhi; Zhang, Yun; Chen, C. L. Philip

    2013-03-01

    In order to assure the communication quality in network systems with heavy traffic and limited bandwidth, a new ATRED (adaptive thresholds random early detection) congestion control algorithm is proposed for the congestion avoidance and resource management of network systems. Different to the traditional AQM (active queue management) algorithms, the control parameters of ATRED are not configured statically, but dynamically adjusted by the adaptive mechanism. By integrating with the adaptive strategy, ATRED alleviates the tuning difficulty of RED (random early detection) and shows a better control on the queue management, and achieve a more robust performance than RED under varying network conditions. Furthermore, a dynamic transmission control protocol-AQM control system using ATRED controller is introduced for the systematic analysis. It is proved that the stability of the network system can be guaranteed when the adaptive mechanism is finely designed. Simulation studies show the proposed ATRED algorithm achieves a good performance in varying network environments, which is superior to the RED and Gentle-RED algorithm, and providing more reliable service under varying network conditions.

  7. Influence of homelessness on acute admissions to hospital.

    PubMed Central

    Lissauer, T; Richman, S; Tempia, M; Jenkins, S; Taylor, B

    1993-01-01

    The aim of this study was to look at the influence of homelessness on acute medical admissions. A prospective case-controlled study was therefore performed on all homeless children admitted through the accident and emergency department over one year, comparing them with the next age matched admission from permanent housing. Assessments made were: whether homelessness or other social factors influenced the doctors' decision to admit; differences in severity of illness; length of stay; and use of primary care. The admitting doctors completed a semi-structured questionnaire during admission about social factors that influenced their decision to admit and graded the severity of the child's illness. The length of hospital stay was recorded. The family's social risk factors and accommodation were assessed at a home visit using a standardised questionnaire and by observation. Seventy homeless children were admitted. Social factors influenced the decision to admit in 77% of homeless children and 43% of controls. More of the homeless children were only mildly ill (33/70) than those from permanent housing (21/70), although three of the homeless children died of overwhelming infections compared with none of the controls. Among homeless families many were recent immigrants (44%). There was a marked increase in socioeconomic deprivation, in major life events in the previous year (median score 3 v 1), and in maternal depression (27% v 8%). Referral to the hospital was made by a general practitioner in only 5/50 (10%) of homeless compared with 18/50 (36%) of controls. Social factors were an important influence on the decision to admit in over three quarters of the homeless children and resulted in admission when less severely ill even when compared with admissions from an inner city population. Even though there was marked social deprivation among the homeless families, the decision to admit was based on vague criteria that need to be further refined. PMID:8259871

  8. Are Articulatory Settings Mechanically Advantageous for Speech Motor Control?

    PubMed Central

    Ramanarayanan, Vikram; Lammert, Adam; Goldstein, Louis; Narayanan, Shrikanth

    2014-01-01

    We address the hypothesis that postures adopted during grammatical pauses in speech production are more “mechanically advantageous” than absolute rest positions for facilitating efficient postural motor control of vocal tract articulators. We quantify vocal tract posture corresponding to inter-speech pauses, absolute rest intervals as well as vowel and consonant intervals using automated analysis of video captured with real-time magnetic resonance imaging during production of read and spontaneous speech by 5 healthy speakers of American English. We then use locally-weighted linear regression to estimate the articulatory forward map from low-level articulator variables to high-level task/goal variables for these postures. We quantify the overall magnitude of the first derivative of the forward map as a measure of mechanical advantage. We find that postures assumed during grammatical pauses in speech as well as speech-ready postures are significantly more mechanically advantageous than postures assumed during absolute rest. Further, these postures represent empirical extremes of mechanical advantage, between which lie the postures assumed during various vowels and consonants. Relative mechanical advantage of different postures might be an important physical constraint influencing planning and control of speech production. PMID:25133544

  9. Potential Mechanisms of Cancer Prevention by Weight Control

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Wang, Weiqun

    Weight control via dietary caloric restriction and/or physical activity has been demonstrated in animal models for cancer prevention. However, the underlying mechanisms are not fully understood. Body weight loss due to negative energy balance significantly reduces some metabolic growth factors and endocrinal hormones such as IGF-1, leptin, and adiponectin, but enhances glucocorticoids, that may be associated with anti-cancer mechanisms. In this review, we summarized the recent studies related to weight control and growth factors. The potential molecular targets focused on those growth factors- and hormones-dependent cellular signaling pathways are further discussed. It appears that multiple factors and multiple signaling cascades, especially for Ras-MAPK-proliferation and PI3K-Akt-anti-apoptosis, could be involved in response to weight change by dietary calorie restriction and/or exercise training. Considering prevalence of obesity or overweight that becomes apparent over the world, understanding the underlying mechanisms among weight control, endocrine change and cancer risk is critically important. Future studies using "-omics" technologies will be warrant for a broader and deeper mechanistic information regarding cancer prevention by weight control.

  10. The Dark Energy Spectroscopic Instrument (DESI) instrument mechanism control systems

    NASA Astrophysics Data System (ADS)

    Coker, Carl T.; Pappalardo, Daniel; Pogge, Richard; Martini, Paul; Derwent, Mark; O'Brien, Thomas P.; Honscheid, Klaus

    2016-08-01

    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We present the design details of the instrument mechanism control systems for the spectrographs. Each spectrograph has a stand-alone mechanism control box that operates the unit's four remotely-operated mechanisms (two shutters and two Hartmannn doors), and provides a suite of temperature and humidity sensors. Each control box is highly modular, and is operated by a dedicated on-board Linux computer to provide all of the control and monitoring functions. We describe our solution for integrating a number of network-connected devices within each unit spectrograph, and describe the basic software architecture.

  11. Dynamic Inversion based Control of a Docking Mechanism

    NASA Technical Reports Server (NTRS)

    Kulkarni, Nilesh V.; Ippolito, Corey; Krishnakumar, Kalmanje

    2006-01-01

    The problem of position and attitude control of the Stewart platform based docking mechanism is considered motivated by its future application in space missions requiring the autonomous docking capability. The control design is initiated based on the framework of the intelligent flight control architecture being developed at NASA Ames Research Center. In this paper, the baseline position and attitude control system is designed using dynamic inversion with proportional-integral augmentation. The inverse dynamics uses a Newton-Euler formulation that includes the platform dynamics, the dynamics of the individual legs along with viscous friction in the joints. Simulation results are presented using forward dynamics simulated by a commercial physics engine that builds the system as individual elements with appropriate joints and uses constrained numerical integration,

  12. Investigation into the reasons for preventable drug related admissions to a medical admissions unit: observational study

    PubMed Central

    Howard, R; Avery, A; Howard, P; Partridge, M

    2003-01-01

    Objective: To describe the drugs and types of medicine management problems most frequently associated with preventable drug related admissions to an acute medical admissions unit. Design: Observation study. Setting: Medical admissions unit in a teaching hospital in Nottingham, UK. Participants: 4093 patients seen by pharmacists on the medical admissions unit between 1 January and 30 June 2001. Main outcome measures: Proportion of admissions that were drug related and preventable, classification of the underlying causes of preventable drug related admissions, and identification of drugs most commonly associated with preventable drug related admissions. Results: Of the admissions seen by pharmacists, 265 (6.5%) were judged to be drug related and 178 (67%) of these were judged to be preventable. Preventable admissions were mainly due to problems with prescribing (63 cases (35%)), monitoring (46 cases (26%)), and adherence to medication (53 cases (30%)). The drugs most commonly implicated were NSAIDs, antiplatelets, antiepileptics, hypoglycaemics, diuretics, inhaled corticosteroids, cardiac glycosides, and beta-blockers. Conclusions: Potentially preventable drug related morbidity was associated with 4.3% of admissions to a medical admissions unit. In 91% of cases these admissions were related to problems with either prescribing, monitoring, or adherence. PMID:12897361

  13. Analysis of femtosecond quantum control mechanisms with colored double pulses

    SciTech Connect

    Vogt, Gerhard; Nuernberger, Patrick; Selle, Reimer; Dimler, Frank; Brixner, Tobias; Gerber, Gustav

    2006-09-15

    Fitness landscapes based on a limited number of laser pulse shape parameters can elucidate reaction pathways and can help to find the underlying control mechanism of optimal pulses determined by adaptive femtosecond quantum control. In a first experiment, we employ colored double pulses and systematically scan both the temporal subpulse separation and the relative amplitude of the two subpulses to acquire fitness landscapes. Comparison with results obtained from a closed-loop experiment demonstrates the capability of fitness landscapes for the revelation of possible control mechanisms. In a second experiment, using transient absorption spectroscopy, we investigate and compare the dependence of the excitation efficiency of the solvated dye molecule 5,5{sup '}-dichloro-11-diphenylamino-3,3{sup '}-diethyl-10,12-ethylene thiatricarbocyanine perchlorate (IR140) on selected pulse shapes in two parametrizations. The results show that very different pulse profiles can be equivalently adequate to maximize a given control objective. Fitness landscapes thus provide valuable information about different pathways along which a molecular system can be controlled with shaped laser pulses.

  14. Mechanisms of abscisic acid-mediated control of stomatal aperture.

    PubMed

    Munemasa, Shintaro; Hauser, Felix; Park, Jiyoung; Waadt, Rainer; Brandt, Benjamin; Schroeder, Julian I

    2015-12-01

    Drought stress triggers an increase in the level of the plant hormone abscisic acid (ABA), which initiates a signaling cascade to close stomata and reduce water loss. Recent studies have revealed that guard cells control cytosolic ABA concentration through the concerted actions of biosynthesis, catabolism as well as transport across membranes. Substantial progress has been made at understanding the molecular mechanisms of how the ABA signaling core module controls the activity of anion channels and thereby stomatal aperture. In this review, we focus on our current mechanistic understanding of ABA signaling in guard cells including the role of the second messenger Ca(2+) as well as crosstalk with biotic stress responses.

  15. Optimal control of underactuated mechanical systems: A geometric approach

    NASA Astrophysics Data System (ADS)

    Colombo, Leonardo; Martín De Diego, David; Zuccalli, Marcela

    2010-08-01

    In this paper, we consider a geometric formalism for optimal control of underactuated mechanical systems. Our techniques are an adaptation of the classical Skinner and Rusk approach for the case of Lagrangian dynamics with higher-order constraints. We study a regular case where it is possible to establish a symplectic framework and, as a consequence, to obtain a unique vector field determining the dynamics of the optimal control problem. These developments will allow us to develop a new class of geometric integrators based on discrete variational calculus.

  16. Mechanical control of spin states in single molecules

    NASA Astrophysics Data System (ADS)

    Parks, J. J.; Champagne, A. R.; Costi, T. A.; Pasupathy, A. N.; Shum, W. W.; Neuscamman, E.; Chan, G. K.-L.; Abruña, H. D.; Ralph, D. C.

    2010-03-01

    We study individual Co(tpy-SH)2 complexes by connecting them within mechanically controllable break-junction devices that allow us to controllably stretch the molecule while measuring its electrical conductance. At low temperature, this molecule produces the Kondo effect, observed as a peak in the conductance at zero bias. We find that as a function of stretching the Kondo peak splits in two, in distinct contrast to behavior observed in spin-1/2 molecules. The temperature dependence of the Kondo signal for the unstretched molecule is in agreement with the scaling prediction for an underscreened S = 1 Kondo effect. The splitting of the Kondo resonance by mechanical stretching can be explained by a spin-orbit-induced lifting of the degeneracy of the S = 1 triplet upon distortion from octahedral symmetry of the Co ion. We observe evidence of the resultant spin anisotropy in the magnetic-field dependence of the Kondo peaks.

  17. Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Slominski, Eric C.

    2003-01-01

    It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

  18. Mechanical stress-controlled tunable active frequency-selective surface

    NASA Astrophysics Data System (ADS)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  19. Multi-finger prehension: control of a redundant mechanical system.

    PubMed

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  20. Rate-Controlling Mechanisms in Five-Power-Law Creep

    SciTech Connect

    Michael E. Kassner

    2004-04-20

    OAK-B135 Rate-Controlling Mechanisms in Five-Power-Law Creep. The initial grant emphasized the rate-controlling processes for five power-law creep. The effort has six aspects: (1) Theory of Taylor hardening from the Frank dislocation network in five power law substructures. (2) The dual dynamical and hardening nature of dislocations in five power law substructures. (3) Determination of the existence of long-range internal stress in five-power law creep dislocation substructures. (4) Dynamic recovery mechanisms associated with dislocation heterogeneities during five power law creep. (5) Versatility of five power law creep concept to other (hcp) crystal structures. (6) Writing of a book on ''Fundamental of Creep in Metals and Alloys'' by M.E. Kassner and Maria-Teresa Perez-Frado (postdoctoral scholar, funded by this project) Elsevier Press, 2004, in press. These areas are consistent with the original goals of this project as delineated in the original proposal to Basic Energy Sciences. The progress in each of these areas will be discussed separately and there will be an attempt to tie each aspect together so as to allow a summary regarding the conclusions with respect to the rate-controlling mechanisms of five power-law creep.

  1. Reducing hospital admissions from nursing homes: a systematic review

    PubMed Central

    2014-01-01

    Background The geriatric nursing home population is vulnerable to acute and deteriorating illness due to advanced age, multiple chronic illnesses and high levels of dependency. Although the detriments of hospitalising the frail and old are widely recognised, hospital admissions from nursing homes remain common. Little is known about what alternatives exist to prevent and reduce hospital admissions from this setting. The objective of this study, therefore, is to summarise the effects of interventions to reduce acute hospitalisations from nursing homes. Methods A systematic literature search was performed in Cochrane Library, PubMed, MEDLINE, EMBASE and ISI Web of Science in April 2013. Studies were eligible if they had a geriatric nursing home study population and were evaluating any type of intervention aiming at reducing acute hospital admission. Systematic reviews, randomised controlled trials, quasi randomised controlled trials, controlled before-after studies and interrupted time series were eligible study designs. The process of selecting studies, assessing them, extracting data and grading the total evidence was done by two researchers individually, with any disagreement solved by a third. We made use of meta-analyses from included systematic reviews, the remaining synthesis is descriptive. Based on the type of intervention, the included studies were categorised in: 1) Interventions to structure and standardise clinical practice, 2) Geriatric specialist services and 3) Influenza vaccination. Results Five systematic reviews and five primary studies were included, evaluating a total of 11 different interventions. Fewer hospital admissions were found in four out of seven evaluations of structuring and standardising clinical practice; in both evaluations of geriatric specialist services, and in influenza vaccination of residents. The quality of the evidence for all comparisons was of low or very low quality, using the GRADE approach. Conclusions Overall, eleven

  2. 28 CFR 54.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 54.300 Admission. (a) General. No person shall, on the basis of sex, be...

  3. 14 CFR 1253.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  4. Lexical Profiles of Thailand University Admission Tests

    ERIC Educational Resources Information Center

    Cherngchawano, Wirun; Jaturapitakkul, Natjiree

    2014-01-01

    University Admission Tests in Thailand are important documents which reflect Thailand's education system. To study at a higher education level, all students generally need to take the University Admission Tests designed by the National Institute of Educational Testing Service (NIETS). For the English test, vocabulary and reading comprehension is…

  5. 7 CFR 15a.21 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Admission. 15a.21 Section 15a.21 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited §...

  6. 7 CFR 15a.21 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Admission. 15a.21 Section 15a.21 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited §...

  7. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  8. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  9. 45 CFR 618.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on... shall, on the basis of sex, be denied admission, or be subjected to discrimination in admission, by...

  10. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  11. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  12. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  13. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  14. Unethical Admissions: Academic Integrity in Question.

    PubMed

    Ansah, Richard Hannis; Aikhuele, Daniel O; Yao, Liu

    2016-11-28

    The increasing unethical practices of graduates' admissions have heightened concerns about the integrity of the academy. This article informs this important subject that affects the students, admission systems, and the entire scientific community, thus, representing an approach against scholarly black market activities including falsified documents and unethical practices by consultants and students' recruitment agencies.

  15. 7 CFR 503.2 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Admission. 503.2 Section 503.2 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL RESEARCH SERVICE, DEPARTMENT OF AGRICULTURE CONDUCT ON PLUM ISLAND ANIMAL DISEASE CENTER § 503.2 Admission. No person will be admitted to PIADC,...

  16. Profile in Action: Linking Admission and Retention

    ERIC Educational Resources Information Center

    Cortes, Carla M.

    2013-01-01

    A profile-oriented retention strategy embraces the admission process as a powerful lever in improving retention and completion rates and recognizes that the student profile can be shaped by changes in admission policies or priorities--even within the current market position of the institution. In addition, the student body can be oriented toward…

  17. Grade Inflation and Law School Admissions

    ERIC Educational Resources Information Center

    Wongsurawat, Winai

    2008-01-01

    Purpose: The purpose of this paper is to evaluate the evidence on whether grade inflation has led to an increasing emphasis on standardized test scores as a criterion for law school admissions. Design/methodology/approach: Fit probabilistic models to admissions data for American law schools during the mid to late 1990s, a period during which…

  18. Strategies and Trends in Admissions Research

    ERIC Educational Resources Information Center

    Fincher, Cameron

    1975-01-01

    Noting that the technical service rendered by the national testing agencies may be an undesirable tradeoff for the active involvement of admissions workers in admissions research, the author suggests that the use of decision theory, quasi-actuarial assessment, quasi-experimental design, and program evaluation strategies would place admissions…

  19. Alphabetical Order Effects in School Admissions

    ERIC Educational Resources Information Center

    Jurajda, Štepán; Münich, Daniel

    2016-01-01

    If school admission committees use alphabetically sorted lists of applicants in their evaluations, one's position in the alphabet according to last name initial may be important in determining access to selective schools. Jurajda and Münich (2010) "Admission to Selective Schools, Alphabetically". "Economics of Education…

  20. Why Do We Stay in Admissions?

    ERIC Educational Resources Information Center

    Piersol, Marion Kandel; And Others

    1993-01-01

    Admission counselors (n=200) completed surveys about employment, title, on-the-job training, travel, and availability and satisfaction with certain responsibilities. Most satisfying admission responsibilities were program organization and implementation, applicant review and decision, and formal presentations. Least satisfying were telemarketing,…

  1. An Admissions Race that's Already Won

    ERIC Educational Resources Information Center

    Stevens, Mitchell L.

    2008-01-01

    The author recently spent a year and a half in the admissions office of a highly selective Eastern college as an ethnographer, seeking to understand just how admissions officers make their decisions. He accompanied them on recruitment trips to high schools and college fairs, helped manage their offices' relentless current of visitors and mail, and…

  2. College Admission Professionals: Who Are We Now?

    ERIC Educational Resources Information Center

    Rapelye, Janet Lavin

    1999-01-01

    Reflects on roles that admission professionals hold within the academic community. Explains that admission professionals are educators and business managers; bring in revenue; and serve as advisors to the president, as spokespeople to alumni/ae, and if fortunate, as counselors to students. Suggests that counselors focus on students because they…

  3. 49 CFR 25.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 25.300 Admission. (a) General. No person shall, on the basis of sex, be...

  4. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  5. 45 CFR 86.21 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  6. 22 CFR 146.300 - Admission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Relations DEPARTMENT OF STATE CIVIL RIGHTS NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 146.300 Admission. (a) General. No person shall, on the basis of sex, be...

  7. 28 CFR 54.300 - Admission.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 54.300 Admission. (a) General. No person shall, on the basis of sex, be...

  8. 43 CFR 41.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Lands: Interior Office of the Secretary of the Interior NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... basis of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  9. 45 CFR 86.21 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex... of sex, be denied admission, or be subjected to discrimination in admission, by any recipient...

  10. Admission to Law School: New Measures

    ERIC Educational Resources Information Center

    Shultz, Marjorie M.; Zedeck, Sheldon

    2012-01-01

    Standardized tests have been increasingly controversial over recent years in high-stakes admission decisions. Their role in operationalizing definitions of merit and qualification is especially contested, but in law schools this challenge has become particularly intense. Law schools have relied on the Law School Admission Test (LSAT) and an INDEX…

  11. Control strategies and mechanisms for active control of sound transmission into a vibro-acoustic enclosure

    NASA Astrophysics Data System (ADS)

    Jin, Guoyong; Feng, Na; Yang, Tiejun

    2011-06-01

    An analytical study was presented on active control of sound transmission into a vibro-acoustic enclosure comprising two flexible plates. Two types of actuators were used, i.e. acoustic actuator and distributed lead zirconate titanate piezoelectric (PZT) actuator instead of point force actuator. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control system configurations were considered, including the structural actuator on the incident plate, actuator on the receiving plate, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control strategy corresponding to each system configuration were compared and discussed. The role and control mechanism of each type of actuator were of particular interest. It was shown that the incident plate actuator is effective in controlling the cavity-dominated modes and the structural modes dominated by the incident plate and receiving plate. Two main control mechanisms are involved in this control configuration, i.e., modal suppressing and modal rearrangement. For control system configuration with only acoustic actuator in the enclosure, the mechanism involved in this arrangement is purely modal suppression. Desirable placements of structural actuators in terms of total potential energy reduction were also discussed.

  12. Control of cardiac alternans by mechanical and electrical feedback

    NASA Astrophysics Data System (ADS)

    Yapari, Felicia; Deshpande, Dipen; Belhamadia, Youssef; Dubljevic, Stevan

    2014-07-01

    A persistent alternation in the cardiac action potential duration has been linked to the onset of ventricular arrhythmia, which may lead to sudden cardiac death. A coupling between these cardiac alternans and the intracellular calcium dynamics has also been identified in previous studies. In this paper, the system of PDEs describing the small amplitude of alternans and the alternation of peak intracellular Ca2+ are stabilized by optimal boundary and spatially distributed actuation. A simulation study demonstrating the successful annihilation of both alternans on a one-dimensional cable of cardiac cells by utilizing the full-state feedback controller is presented. Complimentary to these studies, a three variable Nash-Panfilov model is used to investigate alternans annihilation via mechanical (or stretch) perturbations. The coupled model includes the active stress which defines the mechanical properties of the tissue and is utilized in the feedback algorithm as an independent input from the pacing based controller realization in alternans annihilation. Simulation studies of both control methods demonstrate that the proposed methods can successfully annihilate alternans in cables that are significantly longer than 1 cm, thus overcoming the limitations of earlier control efforts.

  13. Controller modeling and evaluation for PCV electro-mechanical actuator

    NASA Technical Reports Server (NTRS)

    Parker, Joey K.

    1993-01-01

    Hydraulic actuators are currently used to operate the propellant control valves (PCV) for the space shuttle main engine (SSME) and other rocket engines. These actuators are characterized by large power to weight ratios, large force capabilities, and rapid accelerations, which favor their use in control valve applications. However, hydraulic systems are also characterized by susceptibility to contamination, which leads to frequent maintenance requirements. The Control Mechanisms Branch (EP34) of the Component Development Division of the Propulsion Laboratory at the Marshall Space Flight Center (MSFC) has been investigating the application of electromechanical actuators as replacements for the hydraulic units in PCV's over the last few years. This report deals with some testing and analysis of a PCV electromechanical actuator (EMA) designed and fabricated by HR Textron, Inc. This prototype actuator has undergone extensive testing by EP34 personnel since early 1993. At this time, the performance of the HR Textron PCV EMA does not meet requirements for position tracking.

  14. Moving Constraints as Stabilizing Controls in Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Bressan, Alberto; Rampazzo, Franco

    2010-04-01

    The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motion contain terms which are linear or quadratic with respect to time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point by means of oscillating controls. This problem is first reduced to theweak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples.

  15. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs.

    PubMed

    Morales, Julia; Yudes, Carolina; Gómez-Ariza, Carlos J; Bajo, M Teresa

    2015-01-01

    Recent behavioral findings with the AX-Continous Performance Task (AX-CPT; Morales et al., 2013) show that bilinguals only outperform monolinguals under conditions that require the highest adjustment between monitoring (proactive) and inhibitory (reactive) control, which supports the idea that bilingualism modulates the coordination of different control mechanisms. In an ERP experiment we aimed to further investigate the role that bilingualism plays in the dynamic combination of proactive and reactive control in the AX-CPT. Our results strongly indicate that bilingualism facilitates an effective adjustment between both components of cognitive control. First, we replicated previous behavioral results. Second, ERP components indicated that bilingualism influences the conflict monitoring, response inhibition and error monitoring components of control (as indexed by the N2 and P3a elicited by the probe and the error-related negativity following incorrect responses, respectively). Thus, bilinguals exerted higher reactive control than monolinguals but only when they needed to overcome the competing cue-information. These findings join others in suggesting that a better understanding of the cognitive benefits of bilingualism may require consideration of a multi-component perspective.

  16. Atmospheric pollutants and hospital admissions due to pneumonia in children

    PubMed Central

    Negrisoli, Juliana; Nascimento, Luiz Fernando C.

    2013-01-01

    OBJECTIVE: To analyze the relationship between exposure to air pollutants and hospitalizations due to pneumonia in children of Sorocaba, São Paulo, Brazil. METHODS: Time series ecological study, from 2007 to 2008. Daily data were obtained from the State Environmental Agency for Pollution Control for particulate matter, nitric oxide, nitrogen dioxide, ozone, besides air temperature and relative humidity. The data concerning pneumonia admissions were collected in the public health system of Sorocaba. Correlations between the variables of interest using Pearson cofficient were calculated. Models with lags from zero to five days after exposure to pollutants were performed to analyze the association between the exposure to environmental pollutants and hospital admissions. The analysis used the generalized linear model of Poisson regression, being significant p<0.05. RESULTS: There were 1,825 admissions for pneumonia, with a daily mean of 2.5±2.1. There was a strong correlation between pollutants and hospital admissions, except for ozone. Regarding the Poisson regression analysis with the multi-pollutant model, only nitrogen dioxide was statistically significant in the same day (relative risk - RR=1.016), as well as particulate matter with a lag of four days (RR=1.009) after exposure to pollutants. CONCLUSIONS: There was an acute effect of exposure to nitrogen dioxide and a later effect of exposure to particulate matter on children hospitalizations for pneumonia in Sorocaba. PMID:24473956

  17. Controlling Mechanical Properties of Bis-leucine Oxalyl Amide Gels

    NASA Astrophysics Data System (ADS)

    Chang, William; Carvajal, Daniel; Shull, Kenneth

    2011-03-01

    is-leucine oxalyl amide is a low molecular weight gelator capable of gelling polar and organic solvents. A fundamental understanding of self-assembled systems can lead to new methods in drug delivery and the design of new soft material systems. An important feature of self-assembled systems are the intermolecular forces between solvent and gelator molecule; by changing the environment the gel is in, the mechanical properties also change. In this project two variables were considered: the degree of neutralization present for the gelator molecule from neutral to completely ionized, and the concentration of the gelator molecule, from 1 weight percent to 8 weight percent in 1-butanol. Mechanical properties were studied using displacement controlled indentation techniques and temperature sweep rheometry. It has been found that properties such as the storage modulus, gelation temperature and maximum stress allowed increase with bis-leucine oxalyl amide concentration. The results from this study establish a 3-d contour map between the gelator concentration, the gelator degree of ionization and mechanical properties such as storage modulus and maximum stress allowed. The intermolecular forces between the bis-leucine low molecular weight gelator and 1-butanol govern the mechanical properties of the gel system, and understanding these interactions will be key to rationally designed self-assembled systems.

  18. Mechanical control of mitotic progression in single animal cells.

    PubMed

    Cattin, Cedric J; Düggelin, Marcel; Martinez-Martin, David; Gerber, Christoph; Müller, Daniel J; Stewart, Martin P

    2015-09-08

    Despite the importance of mitotic cell rounding in tissue development and cell proliferation, there remains a paucity of approaches to investigate the mechanical robustness of cell rounding. Here we introduce ion beam-sculpted microcantilevers that enable precise force-feedback-controlled confinement of single cells while characterizing their progression through mitosis. We identify three force regimes according to the cell response: small forces (∼5 nN) that accelerate mitotic progression, intermediate forces where cells resist confinement (50-100 nN), and yield forces (>100 nN) where a significant decline in cell height impinges on microtubule spindle function, thereby inhibiting mitotic progression. Yield forces are coincident with a nonlinear drop in cell height potentiated by persistent blebbing and loss of cortical F-actin homogeneity. Our results suggest that a buildup of actomyosin-dependent cortical tension and intracellular pressure precedes mechanical failure, or herniation, of the cell cortex at the yield force. Thus, we reveal how the mechanical properties of mitotic cells and their response to external forces are linked to mitotic progression under conditions of mechanical confinement.

  19. Mechanics of precisely controlled thin film buckling on Elastomeric substrate.

    SciTech Connect

    Sun, Y.; Jiang, H.; Rogers, J.; Huang, Y.; Arizone State Univ.; Beckman Inst.; University of Illinois Urbana-Champaign

    2007-01-01

    Stretchable electronics has many important and emerging applications. Sun et al. [Nature Nanotech. 1, 201 (2006)] recently demonstrated stretchable electronics based on precisely controlled buckle geometries in GaAs and Si nanoribbons on elastomeric substrates. A nonlinear buckling model is presented in this letter to study the mechanics of this type of thin film/substrate system. An analytical solution is obtained for the buckling geometry (wavelength and amplitude) and the maximum strain in buckled thin film. This solution agrees very well with the experiments, and shows explicitly how buckling can significantly reduce the thin film strain to achieve the system stretchability.

  20. Weather, season, and daily stroke admissions in Hong Kong

    NASA Astrophysics Data System (ADS)

    Goggins, William B.; Woo, Jean; Ho, Suzanne; Chan, Emily Y. Y.; Chau, P. H.

    2012-09-01

    Previous studies examining daily temperature and stroke incidence have given conflicting results. We undertook this retrospective study of all stroke admissions in those aged 35 years old and above to Hong Kong public hospitals from 1999 through 2006 in order to better understand the effects of meteorological conditions on stroke risk in a subtropical setting. We used Poisson Generalized Additive Models with daily hemorrhagic (HS) and ischemic stroke (IS) counts separately as outcomes, and daily mean temperature, humidity, solar radiation, rainfall, air pressure, pollutants, flu consultation rates, day of week, holidays, time trend and seasonality as predictors. Lagged effects of temperature, humidity and pollutants were also considered. A total of 23,457 HS and 107,505 IS admissions were analyzed. Mean daily temperature had a strong, consistent, negative linear association with HS admissions over the range (8.2-31.8°C) observed. A 1°C lower average temperature over the same day and previous 4 days (lags 0-4) being associated with a 2.7% (95% CI: 2.0-3.4%, P < .0.0001) higher admission rate after controlling for other variables. This association was stronger among older subjects and females. Higher lag 0-4 average change in air pressure from previous day was modestly associated with higher HS risk. The association between IS and temperature was weaker and apparent only below 22°C, with a 1°C lower average temperature (lags 0-13) below this threshold being associated with a 1.6% (95% CI:1.0-2.2%, P < 0.0001) higher IS admission rate. Pollutant levels were not associated with HS or IS. Future studies should examine HS and IS risk separately.

  1. Frontal theta as a mechanism for cognitive control

    PubMed Central

    Cavanagh, James F.; Frank, Michael J.

    2014-01-01

    Recent advancements in cognitive neuroscience have afforded a description of neural responses in terms of latent algorithmic operations. However, the adoption of this approach to human scalp EEG has been more limited, despite the ability of this methodology to quantify canonical neuronal processes. Here we provide evidence that theta band activities over the mid-frontal cortex appear to reflect a common computation used for realizing the need for cognitive control. Moreover, by virtue of inherent properties of field oscillations, these theta band processes may be used to communicate this need and subsequently implement such control across disparate brain regions. Frontal theta is thus a compelling candidate mechanism by which emergent processes such as ‘cognitive control’ may be biophysically realized. PMID:24835663

  2. RNA-based control mechanisms of Clostridium difficile.

    PubMed

    Soutourina, Olga

    2017-02-16

    Clostridium difficile (CD)-associated diarrhoea is currently the most prevalent nosocomial diarrhoea worldwide. Many characteristics of CD pathogenicity remain poorly understood. Recent data strongly indicate the importance of an RNA network for the control of gene expression in CD. More than 200 regulatory RNAs have been identified by deep sequencing and targeted approaches, including Hfq-dependent trans riboregulators, cis-antisense RNAs, CRISPR RNAs, and c-di-GMP-responsive riboswitches. These regulatory RNAs are involved in the control of major processes in the CD infection cycle, for example motility, biofilm formation, adhesion, sporulation, stress response, and defence against bacteriophages. We will discuss recent advances in elucidation of the original features of RNA-based mechanisms in this important enteropathogen. This knowledge may pave the way for further discoveries in this emergent field.

  3. On Mechanism of Plasma-shock-based Flow Control

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Li, Y. H.; Liang, H.; Jia, M.; Song, H. M.

    2011-09-01

    The mechanism of plasma-shock-based flow control was studied. Due to the high reduced electric field strength and peak power in the nanosecond discharge, a large quantity of high-energy electrons are produced. The quenching of the electronically excited states of N2, the dissociation of O2 and N2, and the recombination of molecular ions with electrons cause fast heating of local air near the electrode edge and fast air pressure rise, thus inducing shock waves. The effectiveness of using nanosecond discharge plasma aerodynamic actuation to improve flow separation control capability was validated at the freestream velocity of 150 m/s. Critical stall angle, lift and drag of NACA 0015 airfoil were measured with and without the nanosecond discharge plasma aerodynamic actuation in the wind tunnel experiments.

  4. Lunar phases and psychiatric hospital admissions.

    PubMed

    Gorvin, J J; Roberts, M S

    1994-12-01

    To assess the lunar hypothesis as predictive of mental health emergencies and antisocial behavior, the relation of the lunar hypothesis and the occurrence of psychiatric hospital admissions of developmentally disabled adults was examined. The full moon phase of the lunar cycle did not explain a higher rate of hospital admission and accounted for only .007% of the variance. A critique of the methodology in prior research led to the suggestion that more immediate stressors and environmental factors are more plausible contributing factors to hospital admission.

  5. Drug related hospital admissions in subspecialities of internal medicine.

    PubMed

    Hallas, J

    1996-04-01

    probably had a specific effect on avoidable DRHs. Admissions caused by adverse ractions to over-the-counter remedies, usually salicylates, were characterised by a particularly inappropriate use of drugs, suggesting that the public may also be a suitable target for interventions. In 1990 the author established the Odense PharmacoEpidemiologic Database (OPED), a research registry with person-identifiable data on computerised refund claims from Funen County. The registry was validated by a cohort study on the association of non-steroidal antiinflammatory drugs (NSAID) and admission for severe upper gastrointestinal bleeding (UGB). All 31,503 recorded NSAID users in Odense during a 19 month period and a control cohort were studied. For both cohorts we obtained data on admissions caused by UGB and other diagnosis- and prescription-data that would be relevant for confounder control. The standardised incidence ratio was 5.5, controlled for age, sex and previous peptic ulcer episodes. A multivariate analyse revealed a number of other risk factors, but no other important confounders. The standardised incidence of UGB was particularly high during the first month of NSAID therapy. The size of the data set permitted an estimate of excess risk within various patient categories. NSAID users over 75 years of age or with a previous peptic ulcer episode had particularly high excess risks. The utilization pattern of NSAIDs was surprisingly sporadic and appeared to favour a high UGB rate for a given sales volume. It is pointed out that individualised dispensing data may be an important tool in future endeavors to control DRH incidences. The data may be used for generating or confirming hypotheses on unknown and suspected ADRs, for studies on risk factors of ADRs, for characterising the population's drug utilization, for identifying objects for interventions and for monitoring the effect of interventions.

  6. Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

    NASA Technical Reports Server (NTRS)

    Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

    1994-01-01

    There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

  7. Control of mechanical systems with rolling constraints: Application to dynamic control of mobile robots

    NASA Astrophysics Data System (ADS)

    Sarkar, Nilanjan; Yun, Xiaoping; Kumar, Vijay

    1994-02-01

    There are many examples of mechanical systems that require rolling contacts between two or more rigid bodies. Rolling contacts engender nonholonomic constraints in an otherwise holonomic system. In this article, we develop a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints. We first present a state space realization of a constrained system. We then discuss the input-output linearization and zero dynamics of the system. This approach is applied to the dynamic control of mobile robots. Two types of control algorithms for mobile robots are investigated: trajectory tracking and path following. In each case, a smooth nonlinear feedback is obtained to achieve asymptotic input-output stability and Lagrange stability of the overall system. Simulation results are presented to demonstrate the effectiveness of the control algorithms and to compare the performane of trajectory-tracking and path-following algorithms.

  8. Mechanisms of spatial attention control in frontal and parietal cortex

    PubMed Central

    Szczepanski, Sara M.; Konen, Christina S.; Kastner, Sabine

    2010-01-01

    Theories of spatial attentional control have been largely based upon studies of patients suffering from visuo-spatial neglect, resulting from circumscribed lesions of frontal and posterior parietal cortex. In the intact brain, the control of spatial attention has been related to a distributed fronto-parietal attention network. Little is known about the nature of the control mechanisms exerted by this network. Here, we used a novel region-of-interest approach to relate activations of the attention network to recently described topographic areas in frontal (FEF, PreCC/IFS) and parietal cortex (IPS1-IPS5, SPL1) and to examine their spatial attention signals. We found that attention signals in most topographic areas were spatially-specific, with stronger responses when attention was directed to the contralateral than to the ipsilateral visual field. Importantly, two hemispheric asymmetries were found. First, a region in only right, but not left superior parietal lobule (SPL1) carried spatial attention signals. Second, left FEF and left posterior parietal cortex (IPS1/2) generated stronger contralateral biasing signals than their counterparts in the right hemisphere. These findings are the first to characterize spatial attention signals in topographic frontal and parietal cortex and provide a neural basis in support of an interhemispheric competition account of spatial attentional control. PMID:20053897

  9. Neural mechanisms of attentional control in mindfulness meditation.

    PubMed

    Malinowski, Peter

    2013-01-01

    The scientific interest in meditation and mindfulness practice has recently seen an unprecedented surge. After an initial phase of presenting beneficial effects of mindfulness practice in various domains, research is now seeking to unravel the underlying psychological and neurophysiological mechanisms. Advances in understanding these processes are required for improving and fine-tuning mindfulness-based interventions that target specific conditions such as eating disorders or attention deficit hyperactivity disorders. This review presents a theoretical framework that emphasizes the central role of attentional control mechanisms in the development of mindfulness skills. It discusses the phenomenological level of experience during meditation, the different attentional functions that are involved, and relates these to the brain networks that subserve these functions. On the basis of currently available empirical evidence specific processes as to how attention exerts its positive influence are considered and it is concluded that meditation practice appears to positively impact attentional functions by improving resource allocation processes. As a result, attentional resources are allocated more fully during early processing phases which subsequently enhance further processing. Neural changes resulting from a pure form of mindfulness practice that is central to most mindfulness programs are considered from the perspective that they constitute a useful reference point for future research. Furthermore, possible interrelations between the improvement of attentional control and emotion regulation skills are discussed.

  10. Basic mechanisms controlling the sweeping efficiency of propagating current sheets

    NASA Astrophysics Data System (ADS)

    Berkery, J. W.; Choueiri, E. Y.

    2006-02-01

    The basic mechanisms controlling the sweeping efficiency of propagating current sheets are investigated through experiments and analytical modelling. The sweeping efficiency of a current sheet in a parallel plate gas-fed pulsed plasma accelerator is defined as the ratio of the current sheet mass to the total available propellant mass. Permeability of neutrals through the sheet, and leakage of mass out of the sheet and into a cathode wake, decrease the sweeping efficiency. The sweeping efficiency of current sheets in argon, neon, helium and hydrogen propellants at different initial pressures was determined through measurements of sheet velocity with high speed photography and of sheet mass with laser interferometry. The mechanism that controls the sweeping efficiency of propagating current sheets was found to be an interplay of two processes: the flux of mass entering the sheet and the leakage of mass at the cathode, with the former dependent on the degree of permeability and the latter dependent on the level of ion current as determined by the ion Hall parameter.

  11. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, L.R.; Crawford, D.C.

    1983-10-06

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  12. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, Lawrence R.; Crawford, Donald C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  13. Molecular mechanisms controlling the migration of striatal interneurons.

    PubMed

    Villar-Cerviño, Verona; Kappeler, Caroline; Nóbrega-Pereira, Sandrina; Henkemeyer, Mark; Rago, Luciano; Nieto, M Angela; Marín, Oscar

    2015-06-10

    In the developing telencephalon, the medial ganglionic eminence (MGE) generates many cortical and virtually all striatal interneurons. While the molecular mechanisms controlling the migration of interneurons to the cortex have been extensively studied, very little is known about the nature of the signals that guide interneurons to the striatum. Here we report that the allocation of MGE-derived interneurons in the developing striatum of the mouse relies on a combination of chemoattractive and chemorepulsive activities. Specifically, interneurons migrate toward the striatum in response to Nrg1/ErbB4 chemoattraction, and avoid migrating into the adjacent cortical territories by a repulsive activity mediated by EphB/ephrinB signaling. Our results also suggest that the responsiveness of MGE-derived striatal interneurons to these cues is at least in part controlled by the postmitotic activity of the transcription factor Nkx2-1. This study therefore reveals parallel mechanisms for the migration of MGE-derived interneurons to the striatum and the cerebral cortex.

  14. Auction Mechanism to Allocate Air Traffic Control Slots

    NASA Technical Reports Server (NTRS)

    Raffarin, Marianne

    2003-01-01

    This article deals with an auction mechanism for airspace slots, as a means of solving the European airspace congestion problem. A disequilibrium, between Air Traffic Control (ATC) services supply and ATC services demand are at the origin of almost one fourth of delays in the air transport industry in Europe. In order to tackle this congestion problem, we suggest modifying both pricing and allocation of ATC services, by setting up an auction mechanism. Objects of the auction will be the right for airlines to cross a part of the airspace, and then to benefit from ATC services over a period corresponding to the necessary time for the crossing. Allocation and payment rules have to be defined according to the objectives of this auction. The auctioneer is the public authority in charge of ATC services, whose aim is to obtain an efficient allocation. Therefore, the social value will be maximized. Another objective is to internalize congestion costs. To that end, we apply the principle of Clarke-Groves mechanism auction: each winner has to pay the externalities imposed on other bidders. The complex context of ATC leads to a specific design for this auction.

  15. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  16. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  17. 43 CFR 4.1141 - Admissions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... directed serves on the requesting party— (1) A sworn statement denying specifically the relevant matters of which an admission is requested; (2) A sworn statement setting forth in detail the reasons why he...

  18. Marketing in Admissions: The Information System Approach.

    ERIC Educational Resources Information Center

    Wofford, O. Douglas; Timmerman, Ed

    1982-01-01

    A marketing information system approach for college admissions is outlined that includes objectives, information needs and sources, a data collection format, and information evaluation. Coordination with other institutional information systems is recommended. (MSE)

  19. The Parent Role in College Admission.

    ERIC Educational Resources Information Center

    Krugman, Mary K.

    1990-01-01

    Discusses techniques secondary school counselors can use to help parents understand and negotiate the college admissions process, including encouraging parental self-assessment; assisting parents to assess student; giving parents special tips; and maintaining open and ethical communication. (ABL)

  20. 28 CFR 549.42 - Involuntary admission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SERVICES Administrative Safeguards for Psychiatric Treatment and Medication § 549.42 Involuntary admission. A court determination is necessary for involuntary hospitalization for psychiatric treatment. A sentenced inmate, not currently committed for psychiatric treatment, who is not able or willing...

  1. Eye mechanics and their implications for eye movement control

    NASA Astrophysics Data System (ADS)

    Koene, Ansgar Roald

    2002-11-01

    The topic of this thesis is the investigation of the mechanical properties of the oculomotor system and the implications of these properties for eye movement control. The investigation was conducted by means of computer models and simulations. This allowed us to combine data from anatomy, physiology and psychophysics with basic principles of physics (mechanics) and mathematics (geometry). In chapter 2 we investigate the degree to which mechanical and neural non-linearities contribute to the kinematic differences between centrifugal and centripetal saccades. On the basis of the velocity profiles of centrifugal and centripetal saccades we calculate the forces and muscle innervations during these eye movements. This was done using an inverted model of the eye plant. Our results indicate that the non-linear force-velocity relationship (i.e. muscle viscosity) of the muscles is probably the cause of the kinematic differences between centrifugal and centripetal saccades. In chapter 3 we calculate the adjustment of the saccadic command that is necessary to compensate for the eye plant non-linearities. These calculations show that the agonist and antagonist muscles require different net saccade signal gain changes. In order to better understand how this gain change is accomplished we use the inverted model of the eye plant (chapter 2) to calculate the muscle innervation profiles of saccades with different starting orientations. Based on these calculations we conclude that the saccade signal gain changes are accomplished primarily by changes in the magnitude of the saccade signal. In chapter 4 we examine the requirements that the oculomotor system must meet for the eye to be able to make desired gaze changes and fixate at various eye orientations. We first determine how the axes of action (i.e. unit moment vectors) of the muscles are related to eye orientation and the location of the effective muscle origin (i.e. the muscle pulleys). Next we show how this relation constrains

  2. Phloem transport: a review of mechanisms and controls.

    PubMed

    De Schepper, Veerle; De Swaef, Tom; Bauweraerts, Ingvar; Steppe, Kathy

    2013-11-01

    It is generally believed that an osmotically generated pressure gradient drives the phloem mass flow. So far, this widely accepted Münch theory has required remarkably few adaptations, but the debate on alternative and additional hypotheses is still ongoing. Recently, a possible shortcoming of the Münch theory has been pointed out, suggesting that the Münch pressure flow is more suitable for herbs than for trees. Estimation of the phloem resistance indicates that a point might be reached in long sieve tubes where the pressure required to drive the Münch flow cannot be generated. Therefore, the relay hypothesis regained belief as it implies that the sieve tubes are shorter then the plant's axial axis. In the source phloem, three different loading strategies exist which probably result from evolutionary advantages. Passive diffusion seems to be the most primitive one, whereas active loading strategies substantially increase the growth potential. Along the transport phloem, a leakage-retrieval mechanism is observed. Appreciable amounts of carbohydrates are lost from the sieve tubes to feed the lateral sinks, while a part of these lost carbohydrates is subsequently reloaded into the sieve tubes. This mechanism is probably involved to buffer short-term irregularities in phloem turgor and gradient. In the long term, the mechanism controls the replenishment and remobilization of lateral stem storage tissues. As phloem of higher plants has multiple functions in plant development, reproduction, signalling, and growth, the fundamental understanding of the mechanisms behind phloem transport should be elucidated to increase our ability to influence plant growth and development.

  3. Fixed and flexible formularies as cost-control mechanisms.

    PubMed

    Dewa, Carolyn S; Hoch, Jeffrey S

    2003-06-01

    The purpose of this review is to consider the prevalent types of fixed and flexible formularies, the general economic principles on which they are based and the evidence for their effectiveness in controlling rising drug expenditures. The principal-agent relationship and economic model underlying the various types of formularies are described. The principal-agent model describes a relationship where there is an asymmetry of information between two parties involved in a particular task. As a result of this asymmetry of information, the party with less information (the principal) allows the party with more information (the agent) to make decisions about that task or activity for them. In the case of formularies and cost-control, the principal is the payer. Depending on the incentives offered by the formulary, the agent can alternately be the prescriber, dispenser or patient. The success of a formulary type to control costs is dependent on two main factors. First, the payer (the principal) must identify the agent for whom it is reasonable to create incentives that incorporate the financial risks associated with use of the drugs. Second, the payer must develop a structure that best aligns the principal and agent objectives. The principal-agent framework serves as the vehicle through which the authors examine five major types of formularies (i.e., closed, best available price, reference-based pricing, tiered and open formularies) and their inherent incentives and limitations. The evidence for their effectiveness as cost-control mechanisms is reviewed and the system factors that can affect formulary success will be discussed. Finally, the authors' observations are summarized and interpreted, and suggested implications for future use of formularies in controlling the costs of pharmaceutical use are offered.

  4. Neural mechanisms of brain-computer interface control.

    PubMed

    Halder, S; Agorastos, D; Veit, R; Hammer, E M; Lee, S; Varkuti, B; Bogdan, M; Rosenstiel, W; Birbaumer, N; Kübler, A

    2011-04-15

    Brain-computer interfaces (BCIs) enable people with paralysis to communicate with their environment. Motor imagery can be used to generate distinct patterns of cortical activation in the electroencephalogram (EEG) and thus control a BCI. To elucidate the cortical correlates of BCI control, users of a sensory motor rhythm (SMR)-BCI were classified according to their BCI control performance. In a second session these participants performed a motor imagery, motor observation and motor execution task in a functional magnetic resonance imaging (fMRI) scanner. Group difference analysis between high and low aptitude BCI users revealed significantly higher activation of the supplementary motor areas (SMA) for the motor imagery and the motor observation tasks in high aptitude users. Low aptitude users showed no activation when observing movement. The number of activated voxels during motor observation was significantly correlated with accuracy in the EEG-BCI task (r=0.53). Furthermore, the number of activated voxels in the right middle frontal gyrus, an area responsible for processing of movement observation, correlated (r=0.72) with BCI-performance. This strong correlation highlights the importance of these areas for task monitoring and working memory as task goals have to be activated throughout the BCI session. The ability to regulate behavior and the brain through learning mechanisms involving imagery such as required to control a BCI constitutes the consequence of ideo-motor co-activation of motor brain systems during observation of movements. The results demonstrate that acquisition of a sensorimotor program reflected in SMR-BCI-control is tightly related to the recall of such sensorimotor programs during observation of movements and unrelated to the actual execution of these movement sequences.

  5. Aging interferes central control mechanism for eccentric muscle contraction.

    PubMed

    Yao, Wan X; Li, Jinqi; Jiang, Zhiguo; Gao, Jia-Hong; Franklin, Crystal G; Huang, Yufei; Lancaster, Jack L; Yue, Guang H

    2014-01-01

    Previous studies report greater activation in the cortical motor network in controlling eccentric contraction (EC) than concentric contraction (CC) despite lower muscle activation level associated with EC vs. CC in healthy, young individuals. It is unknown, however, whether elderly people exhibiting increased difficulties in performing EC than CC possess this unique cortical control mechanism for EC movements. To address this question, we examined functional magnetic resonance imaging (fMRI) data acquired during EC and CC of the first dorsal interosseous (FDI) muscle in 11 young (20-32 years) and 9 old (67-73 years) individuals. During the fMRI experiment, all subjects performed 20 CC and 20 EC of the right FDI with the same angular distance and velocity. The major findings from the behavioral and fMRI data analysis were that (1) movement stability was poorer in EC than CC in the old but not the young group; (2) similar to previous electrophysiological and fMRI reports, the EC resulted in significantly stronger activation in the motor control network consisting of primary, secondary and association motor cortices than CC in the young and old groups; (3) the biased stronger activation towards EC was significantly greater in the old than the young group especially in the secondary and association cortices such as supplementary and premotor motor areas and anterior cingulate cortex; and (4) in the primary motor and sensory cortices, the biased activation towards EC was significantly greater in the young than the old group. Greater activation in higher-order cortical fields for controlling EC movement by elderly adults may reflect activities in these regions to compensate for aging-related impairments in the ability to control complex EC movements. Our finding is useful for potentially guiding the development of targeted therapies to counteract age-related movement deficits and to prevent injury.

  6. Flow control mechanism of capillary driven flow in microchannel using non-mechanical forces

    NASA Astrophysics Data System (ADS)

    Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

    2016-11-01

    The capillary driven flow in microchannel is a self-driven flow by the natural phenomenon called surface tension of the fluid. The gradients in surface tension force which influence the flow field in microchannel is generated by the modulation of contact angle through a defined hydrophilization of the PDMS (Polydimethylsiloxane) microchannel surface. PDMS which is hydrophobic in nature is treated with various surface treatments in order to convert it to hydrophilic. The contact angle made by the fluid with the PDMS microchannel surface is altered when the surface is converted from hydrophobic to hydrophilic. The flow rate of fluid in the microchannel is directly proportional to the hydrophilicity of that microchannel since the capillary force which is the driving force of the flow is dependent on the contact angle. Flow control mechanism of capillary driven flow in microchannel using non-mechanical forces is developed by treating the microchannel surfaces with various surface treatments. The precise control of the surface characteristics like hydrophilicity and roughness of the miocrochannel helps to control the capillary flow in microchannel. The flow rate variation with respect to the various surface treated channels are studied. Principal Investigator.

  7. Sway patterns in orthostatic tremor: impairment of postural control mechanisms.

    PubMed

    Bacsi, Ann M; Fung, Victor S C; Colebatch, James G

    2005-11-01

    Sway parameters in orthostatic tremor (OT) patients were compared with age-matched controls. The effects of vision (eyes open or closed), stance width (feet apart or together), and external support (with or without) on sway and 14-18 Hz energy were measured. Sway in OT patients decreased in the presence of each of the stabilizing factors but the extent of benefit obtained by OT patients was significantly less than controls for support for the sagittal plane (22% vs. 42% decrease; P < 0.01) and feet apart in the mediolateral plane (38% vs. 65% decrease; P < 0.01). Three patients with proprioceptive loss also had a reduced response to these factors. Energy in the 14-18 Hz range did not always change in parallel with sway levels. Vision suppresses activity at the OT frequency in patients. Postural control mechanisms in OT remain responsive to postural conditions, but patients differ significantly from normals in the degree of their responsiveness. OT appears to have disruption of the normal generation or processing of proprioceptive signals as one of its important components.

  8. Immigration, moving house and psychiatric admissions.

    PubMed

    Johansson, L M; Sundquist, J; Johansson, S E; Bergman, B

    1998-08-01

    This study was designed to elucidate psychiatric admission rates for native Swedes and foreign-born individuals during the period 1991-1994, when Sweden had a great influx of refugees. During the same period, and even earlier, psychiatric in-patient care had been reduced. Tests of differences between Swedes and foreign-born individuals in first psychiatric admission rates were performed using Poisson regressions, and the risk of a readmission was assessed using a proportional hazard model. Foreign-born individuals and native Swedes, both males and females, showed a similar admission pattern with regard to the number of admissions. Foreign-born males under 55 years of age and foreign-born females under 35 years of age had significantly higher admission rates than native Swedes. In total, native Swedes, both males and females, were hospitalized for a significantly longer period than the foreign-born subjects. About 43% of the patients were readmitted. The risk of a readmission was significantly increased among those with a high rate of internal migration. The high admission rates for young foreign-born individuals might be explained by a high incidence of mental illness owing to the trauma of being violently forced to migrate, acculturation difficulties, or unsatisfactory social circumstances such as high unemployment. The shorter hospitalization time could be due to undertreatment or less serious mental illness.

  9. Chemo-mechanical control of neural stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  10. Shape-Controlled Growth of Carbon Nanostructures: Yield and Mechanism.

    PubMed

    Ma, Yao; Sun, Xiao; Yang, Nianjun; Xia, Junhai; Zhang, Lei; Jiang, Xin

    2015-08-24

    Carbon nanostructures with precisely controlled shapes are difficult materials to synthesize. A facet-selective-catalytic process was thus proposed to synthesize polymer-linked carbon nanostructures with different shapes, covering straight carbon nanofiber, carbon nano Y-junction, carbon nano-hexapus, and carbon nano-octopus. A thermal chemical vapor deposition process was applied to grow these multi-branched carbon nanostructures at temperatures lower than 350 °C. Cu nanoparticles were utilized as the catalyst and acetylene as the reaction gas. The growth of those multi-branched nanostructures was realized through the selective growth of polymer-like sheets on certain indexed facets of Cu catalyst. The vapor-facet-solid (VFS) mechanism, a new growth mode, has been proposed to interpret such a growth in the steps of formation, diffusion, and coupling of carbon-containing oligomers, as well as their final precipitation to form nanostructures on the selective Cu facets.

  11. Bacterial cell curvature through mechanical control of cell growth

    PubMed Central

    Cabeen, Matthew T; Charbon, Godefroid; Vollmer, Waldemar; Born, Petra; Ausmees, Nora; Weibel, Douglas B; Jacobs-Wagner, Christine

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics of cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology. PMID:19279668

  12. A comparison of drive mechanisms for precision motion controlled stages

    SciTech Connect

    Buice, E S; Yang, H; Otten, D; Smith, S T; Hocken, R J; Trumper, D L; Seugling, R M

    2006-03-22

    This abstract presents a comparison of two drive mechanisms, a Rohlix{reg_sign} drive and a polymer nut drive, for precision motion controlled stages. A single-axis long-range stage with a 50 mm traverse combined with a short-range stage with a 16 {micro}m traverse at a operational bandwidth of 2.2 kHz were developed to evaluate the performance of the drives. The polymer nut and Rohlix{reg_sign} drives showed 4 nm RMS and 7 nm RMS positioning capabilities respectively, with traverses of 5 mm at a maximum velocity of 0.15 mm{sup -}s{sup -1} with the short range stage operating at a 2.2 kHz bandwidth. Further results will be presented in the subsequent sections.

  13. Protein synthesis as an integral quality control mechanism during ageing.

    PubMed

    Charmpilas, Nikolaos; Daskalaki, Ioanna; Papandreou, Margarita Elena; Tavernarakis, Nektarios

    2015-09-01

    Ageing is manifested as functional and structural deterioration that affects cell and tissue physiology. mRNA translation is a central cellular process, supplying cells with newly synthesized proteins. Accumulating evidence suggests that alterations in protein synthesis are not merely a corollary but rather a critical factor for the progression of ageing. Here, we survey protein synthesis regulatory mechanisms and focus on the pre-translational regulation of the process exerted by non-coding RNA species, RNA binding proteins and alterations of intrinsic RNA properties. In addition, we discuss the tight relationship between mRNA translation and two central pathways that modulate ageing, namely the insulin/IGF-1 and TOR signalling cascades. A thorough understanding of the complex interplay between protein synthesis regulation and ageing will provide critical insights into the pathogenesis of age-related disorders, associated with impaired proteostasis and protein quality control.

  14. Mechanisms Controlling Virulence Thresholds of Mixed Viral Populations ▿

    PubMed Central

    Lancaster, Karen Z.; Pfeiffer, Julie K.

    2011-01-01

    The propensity of RNA viruses to revert attenuating mutations contributes to disease and complicates vaccine development. Despite the presence of virulent revertant viruses in some live-attenuated vaccines, disease from vaccination is rare. This suggests that in mixed viral populations, attenuated viruses may limit the pathogenesis of virulent viruses, thus establishing a virulence threshold. Here we examined virulence thresholds using mixtures of virulent and attenuated viruses in a transgenic mouse model of poliovirus infection. We determined that a 1,000-fold excess of the attenuated Sabin strain of poliovirus was protective against disease induced by the virulent Mahoney strain. Protection was induced locally, and inactivated virus conferred protection. Treatment with a poliovirus receptor-blocking antibody phenocopied the protective effect of inactivated viruses in vitro and in vivo, suggesting that one mechanism controlling virulence thresholds may be competition for a viral receptor. Additionally, the type I interferon response reduces poliovirus pathogenesis; therefore, we examined virulence thresholds in mice lacking the alpha/beta interferon receptor. We found that the attenuated virus was virulent in immunodeficient mice due to the enhanced replication and reversion of attenuating mutations. Therefore, while the type I interferon response limits the virulence of the attenuated strain by reducing replication, protection from disease conferred by the attenuated strain in immunocompetent mice can occur independently of replication. Our results identified mechanisms controlling the virulence of mixed viral populations and indicate that live-attenuated vaccines containing virulent virus may be safe, as long as virulent viruses are present at levels below a critical threshold. PMID:21795346

  15. Mitochondria-controlled signaling mechanisms of brain protection in hypoxia

    PubMed Central

    Lukyanova, Ludmila D.; Kirova, Yulia I.

    2015-01-01

    The article is focused on the role of the cell bioenergetic apparatus, mitochondria, involved in development of immediate and delayed molecular mechanisms for adaptation to hypoxic stress in brain cortex. Hypoxia induces reprogramming of respiratory chain function and switching from oxidation of NAD-related substrates (complex I) to succinate oxidation (complex II). Transient, reversible, compensatory activation of respiratory chain complex II is a major mechanism of immediate adaptation to hypoxia necessary for (1) succinate-related energy synthesis in the conditions of oxygen deficiency and formation of urgent resistance in the body; (2) succinate-related stabilization of HIF-1α and initiation of its transcriptional activity related with formation of long-term adaptation; (3) succinate-related activation of the succinate-specific receptor, GPR91. This mechanism participates in at least four critical regulatory functions: (1) sensor function related with changes in kinetic properties of complex I and complex II in response to a gradual decrease in ambient oxygen concentration; this function is designed for selection of the most efficient pathway for energy substrate oxidation in hypoxia; (2) compensatory function focused on formation of immediate adaptive responses to hypoxia and hypoxic resistance of the body; (3) transcriptional function focused on activated synthesis of HIF-1 and the genes providing long-term adaptation to low pO2; (4) receptor function, which reflects participation of mitochondria in the intercellular signaling system via the succinate-dependent receptor, GPR91. In all cases, the desired result is achieved by activation of the succinate-dependent oxidation pathway, which allows considering succinate as a signaling molecule. Patterns of mitochondria-controlled activation of GPR-91- and HIF-1-dependent reaction were considered, and a possibility of their participation in cellular-intercellular-systemic interactions in hypoxia and adaptation was

  16. Passive Flow Separation Control Mechanism Inspired by Shark Skin

    NASA Astrophysics Data System (ADS)

    Oakley, India; Lang, Amy

    2015-11-01

    The following experimental work seeks to examine shark scales as passive flow-actuated separation control mechanisms. It is hypothesized that the actuation of these scales can in fact reduce pressure drag by inhibiting flow reversal and thereby prevent flow separation. In order to examine this mechanism at a fundamental level, three-dimensional sharkskin scales were simplified and modeled as two-dimensional flaps. To further simplify the experiment, the flaps were observed within a laminar boundary layer. The laminar boundary layer was grown over a long flat plate that was placed inside a water tunnel. A rotating cylinder was also used to induce an unsteady, increasing adverse pressure gradient, which generated a reversing flow. In order to visualize the potential actuation of the two-dimensional flaps DPIV (digital particle image velocimetry) was utilized. Three main objectives for this work included, the actuation of the two-dimensional flaps, the resistance to a reversed flow as a result of flap actuation and the prevention of flow separation. However once the experiment was conducted the flaps did not perform as previously hypothesized. The adverse pressure gradient induced by the rotating cylinder did not produce a reversing flow powerful enough to actuate the flaps. NSF REU Site Award 1358991.

  17. Lattice Metamaterials with Mechanically Tunable Poisson's Ratio for Vibration Control

    NASA Astrophysics Data System (ADS)

    Chen, Yanyu; Li, Tiantian; Scarpa, Fabrizio; Wang, Lifeng

    2017-02-01

    Metamaterials with artificially designed architectures are increasingly considered as new paradigmatic material systems with unusual physical properties. Here, we report a class of architected lattice metamaterials with mechanically tunable negative Poisson's ratios and vibration-mitigation capability. The proposed lattice metamaterials are built by replacing regular straight beams with sinusoidally shaped ones, which are highly stretchable under uniaxial tension. Our experimental and numerical results indicate that the proposed lattices exhibit extreme Poisson's-ratio variations between -0.7 and 0.5 over large tensile deformations up to 50%. This large variation of Poisson's-ratio values is attributed to the deformation pattern switching from bending to stretching within the sinusoidally shaped beams. The interplay between the multiscale (ligament and cell) architecture and wave propagation also enables remarkable broadband vibration-mitigation capability of the lattice metamaterials, which can be dynamically tuned by an external mechanical stimulus. The material design strategy provides insights into the development of classes of architected metamaterials with potential applications including energy absorption, tunable acoustics, vibration control, responsive devices, soft robotics, and stretchable electronics.

  18. Cellular and Humoral Mechanisms Involved in the Control of Tuberculosis

    PubMed Central

    Zuñiga, Joaquin; Torres-García, Diana; Santos-Mendoza, Teresa; Rodriguez-Reyna, Tatiana S.; Granados, Julio; Yunis, Edmond J.

    2012-01-01

    Mycobacterium tuberculosis (Mtb) infection is a major international public health problem. One-third of the world's population is thought to have latent tuberculosis, a condition where individuals are infected by the intracellular bacteria without active disease but are at risk for reactivation, if their immune system fails. Here, we discuss the role of nonspecific inflammatory responses mediated by cytokines and chemokines induced by interaction of innate receptors expressed in macrophages and dendritic cells (DCs). We also review current information regarding the importance of several cytokines including IL-17/IL-23 in the development of protective cellular and antibody-mediated protective responses against Mtb and their influence in containment of the infection. Finally, in this paper, emphasis is placed on the mechanisms of failure of Mtb control, including the immune dysregulation induced by the treatment with biological drugs in different autoimmune diseases. Further functional studies, focused on the mechanisms involved in the early host-Mtb interactions and the interplay between host innate and acquired immunity against Mtb, may be helpful to improve the understanding of protective responses in the lung and in the development of novel therapeutic and prophylactic tools in TB. PMID:22666281

  19. Unconventional mechanisms control cyclic respiratory gas release in flying Drosophila.

    PubMed

    Lehmann, Fritz-Olaf; Heymann, Nicole

    2005-10-01

    The high power output of flight muscles places special demands on the respiratory gas exchange system in insects. In small insects, respiration relies on diffusion, and for elevated locomotor performance such as flight, instantaneous gas exchange rates typically co-vary with the animal's metabolic activity. By contrast, under certain conditions, instantaneous release rate of carbon dioxide from the fruit fly Drosophila flying in a virtual-reality flight arena may oscillate distinctly at low frequency (0.37+/-0.055 Hz), even though flight muscle mechanical power output requires constant metabolic activity. Cross-correlation analysis suggests that this uncoupling between respiratory and metabolic rate is not driven by conventional types of convective flow reinforcement such as abdominal pumping, but might result from two unusual mechanisms for tracheal breathing. Simplified analytical modeling of diffusive tracheal gas exchange suggests that cyclic release patterns in the insect occur as a consequence of the stochastically synchronized control of spiracle opening area by the four large thoracic spiracles. Alternatively, in-flight motion analysis of the abdomen and proboscis using infra-red video imaging suggests utilization of the proboscis extension reflex (PER) for tracheal convection. Although the respiratory benefit of synchronized spiracle opening activity in the fruit fly is unclear, proboscis-induced tracheal convection might potentially help to balance the local oxygen supply between different body compartments of the flying animal.

  20. Internal Control Rod Drive Mechanisms, Design Options for IRIS

    SciTech Connect

    Conway, Lawrence E.; Petrovic, Bojan

    2004-07-01

    IRIS (International Reactor Innovative and Secure) is a medium-power (335 MWe) PWR with an integral, primary circuit configuration, where all the reactor coolant system components are contained within the reactor vessel. This integral configuration is a key reason for the success of IRIS' 'safety-by-design' approach, whereby accident initiators are eliminated or the accident consequences and/or frequency are reduced. The most obvious example of the IRIS safety by design approach is the elimination of large LOCA's, since the integral reactor coolant system has no large loop piping. Another serious accident scenario that is being addressed in IRIS is the postulated ejection of a reactor control cluster assembly (RCCA). This accident initiator can be eliminated by locating the RCCA drive mechanisms (CRDMs) inside the reactor vessel. This eliminates the mechanical drive rod penetration between the RCCA and the external CRDM, eliminating the potential for differential pressure across the pressure boundary, and thus eliminating 'by design' the possibility for rod ejection accident. Moreover, the elimination of the 'large' drive-rod penetrations and the external CRDM pressure housings decreases the likelihood of boric acid leakage and subsequent corrosion of the reactor pressure boundary (like the Davis-Besse incident). This paper will discuss the IRIS top level design requirements and objectives for internal CRDMs, and provide examples candidate designs and their specific performance characteristics. (authors)

  1. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced by Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.; Tainger, Karen M.

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties demonstrated for electron beam deposited aluminum and titanium alloys are comparable to wrought products, although the microstructures of the deposits exhibit cast features. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. Tensile mechanical properties and microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains with interior dendritic structures, described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  2. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.; Taminger, Karen M. B.; Begley, Matthew

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  3. Redox Control of Leukemia: From Molecular Mechanisms to Therapeutic Opportunities

    PubMed Central

    Irwin, Mary E.; Rivera-Del Valle, Nilsa

    2013-01-01

    Abstract Reactive oxygen species (ROS) play both positive and negative roles in the proliferation and survival of a cell. This dual nature has been exploited by leukemia cells to promote growth, survival, and genomic instability—some of the hallmarks of the cancer phenotype. In addition to altered ROS levels, many antioxidants are dysregulated in leukemia cells. Together, the production of ROS and the expression and activity of antioxidant enzymes make up the primary redox control of leukemia cells. By manipulating this system, leukemia cells gain proliferative and survival advantages, even in the face of therapeutic insults. Standard treatment options have improved leukemia patient survival rates in recent years, although relapse and the development of resistance are persistent challenges. Therapies targeting the redox environment show promise for these cases. This review highlights the molecular mechanisms that control the redox milieu of leukemia cells. In particular, ROS production by the mitochondrial electron transport chain, NADPH oxidase, xanthine oxidoreductase, and cytochrome P450 will be addressed. Expression and activation of antioxidant enzymes such as superoxide dismutase, catalase, heme oxygenase, glutathione, thioredoxin, and peroxiredoxin are perturbed in leukemia cells, and the functional consequences of these molecular alterations will be described. Lastly, we delve into how these pathways can be potentially exploited therapeutically to improve treatment regimens and promote better outcomes for leukemia patients. Antioxid. Redox Signal. 18, 1349–1383. PMID:22900756

  4. Dissociable early attentional control mechanisms underlying cognitive and affective conflicts

    PubMed Central

    Chen, Taolin; Kendrick, Keith M.; Feng, Chunliang; Sun, Shiyue; Yang, Xun; Wang, Xiaogang; Luo, Wenbo; Yang, Suyong; Huang, Xiaoqi; Valdés-Sosa, Pedro A.; Gong, Qiyong; Fan, Jin; Luo, Yue-Jia

    2016-01-01

    It has been well documented that cognitive conflict is sensitive to the relative proportion of congruent and incongruent trials. However, few studies have examined whether affective conflict processing is modulated as a function of proportion congruency (PC). To address this question we recorded event-related potentials (ERP) while subjects performed both cognitive and affective face-word Stroop tasks. By varying the proportion of congruent and incongruent trials in each block, we examined the extent to which PC impacts both cognitive and affective conflict control at different temporal stages. Results showed that in the cognitive task an anteriorly localized early N2 component occurred predominantly in the low proportion congruency context, whereas in the affective task it was found to occur in the high proportion congruency one. The N2 effects across the two tasks were localized to the dorsolateral prefrontal cortex, where responses were increased in the cognitive task but decreased in the affective one. Furthermore, high proportions of congruent items produced both larger amplitude of a posteriorly localized sustained potential component and a larger behavioral Stroop effect in cognitive and affective tasks. Our findings suggest that cognitive and affective conflicts engage early dissociable attentional control mechanisms and a later common conflict response system. PMID:27892513

  5. Cognitive Control Deficits in Schizophrenia: Mechanisms and Meaning

    PubMed Central

    Lesh, Tyler A; Niendam, Tara A; Minzenberg, Michael J; Carter, Cameron S

    2011-01-01

    Although schizophrenia is an illness that has been historically characterized by the presence of positive symptomatology, decades of research highlight the importance of cognitive deficits in this disorder. This review proposes that the theoretical model of cognitive control, which is based on contemporary cognitive neuroscience, provides a unifying theory for the cognitive and neural abnormalities underlying higher cognitive dysfunction in schizophrenia. To support this model, we outline converging evidence from multiple modalities (eg, structural and functional neuroimaging, pharmacological data, and animal models) and samples (eg, clinical high risk, genetic high risk, first episode, and chronic subjects) to emphasize how dysfunction in cognitive control mechanisms supported by the prefrontal cortex contribute to the pathophysiology of higher cognitive deficits in schizophrenia. Our model provides a theoretical link between cellular abnormalities (eg, reductions in dentritic spines, interneuronal dysfunction), functional disturbances in local circuit function (eg, gamma abnormalities), altered inter-regional cortical connectivity, a range of higher cognitive deficits, and symptom presentation (eg, disorganization) in the disorder. Finally, we discuss recent advances in the neuropharmacology of cognition and how they can inform a targeted approach to the development of effective therapies for this disabling aspect of schizophrenia. PMID:20844478

  6. A Presynaptic Gain Control Mechanism Fine-Tunes Olfactory Behavior

    PubMed Central

    Root, Cory M.; Masuyama, Kaoru; Green, David S.; Enell, Lina E.; Nässel, Dick R.; Lee, Chi-Hon; Wang, Jing W.

    2008-01-01

    Early sensory processing can play a critical role in sensing environmental cues. We have investigated the physiological and behavioral function of gain control at the first synapse of olfactory processing in Drosophila. We report that olfactory receptor neurons (ORNs) express the GABAB receptor (GABABR) and its expression expands the dynamic range of ORN synaptic transmission that is preserved in projection neuron responses. Strikingly, we find that different ORN channels have unique baseline levels of GABABR expression. ORNs that sense the aversive odorant CO2 do not express GABABRs nor exhibit any presynaptic inhibition. In contrast, pheromone-sensing ORNs express a high level of GABABRs and exhibit strong presynaptic inhibition. Furthermore, a behavioral significance of presynaptic inhibition was revealed by a courtship behavior in which pheromone-dependent mate localization is impaired in flies that lack GABABRs in specific ORNs. Together, these findings indicate that different olfactory receptor channels may employ heterogeneous presynaptic gain control as a mechanism to allow an animal’s innate behavioral responses to match its ecological needs. PMID:18667158

  7. Electro-Mechanical Actuator. DC Resonant Link Controller

    NASA Technical Reports Server (NTRS)

    Schreiner, Kenneth E.

    1996-01-01

    This report summarizes the work performed on the 68 HP electro-mechanical actuator (EMA) system developed on NASA contract for the Electrical Actuation (ELA) Technology Bridging Program. The system was designed to demonstrate the capability of large, high power linear ELAs for applications such as Thrust Vector Control (TVC) on rocket engines. It consists of a motor controller, drive electronics and a linear actuator capable of up to 32,00 lbs loading at 7.4 inches/second. The drive electronics are based on the Resonant DC link concept and operate at a nominal frequency of 55 kHz. The induction motor is a specially designed high speed, low inertia motor capable of a 68 peak HP. The actuator was originally designed by MOOG Aerospace under an internal R & D program to meet Space Shuttle Main Engine (SSME) TVC requirements. The design was modified to meet this programs linear rate specification of 7.4 inches/second. The motor and driver were tested on a dynamometer at the Martin Marietta Space Systems facility. System frequency response, step response and force-velocity tests were conducted at the MOOG Aerospace facility. A complete description of the system and all test results can be found in the body of the report.

  8. Dissociable early attentional control mechanisms underlying cognitive and affective conflicts.

    PubMed

    Chen, Taolin; Kendrick, Keith M; Feng, Chunliang; Sun, Shiyue; Yang, Xun; Wang, Xiaogang; Luo, Wenbo; Yang, Suyong; Huang, Xiaoqi; Valdés-Sosa, Pedro A; Gong, Qiyong; Fan, Jin; Luo, Yue-Jia

    2016-11-28

    It has been well documented that cognitive conflict is sensitive to the relative proportion of congruent and incongruent trials. However, few studies have examined whether affective conflict processing is modulated as a function of proportion congruency (PC). To address this question we recorded event-related potentials (ERP) while subjects performed both cognitive and affective face-word Stroop tasks. By varying the proportion of congruent and incongruent trials in each block, we examined the extent to which PC impacts both cognitive and affective conflict control at different temporal stages. Results showed that in the cognitive task an anteriorly localized early N2 component occurred predominantly in the low proportion congruency context, whereas in the affective task it was found to occur in the high proportion congruency one. The N2 effects across the two tasks were localized to the dorsolateral prefrontal cortex, where responses were increased in the cognitive task but decreased in the affective one. Furthermore, high proportions of congruent items produced both larger amplitude of a posteriorly localized sustained potential component and a larger behavioral Stroop effect in cognitive and affective tasks. Our findings suggest that cognitive and affective conflicts engage early dissociable attentional control mechanisms and a later common conflict response system.

  9. Mechanical stratigraphic controls on natural fracture spacing and penetration

    NASA Astrophysics Data System (ADS)

    McGinnis, Ronald N.; Ferrill, David A.; Morris, Alan P.; Smart, Kevin J.; Lehrmann, Daniel

    2017-02-01

    Fine-grained low permeability sedimentary rocks, such as shale and mudrock, have drawn attention as unconventional hydrocarbon reservoirs. Fracturing - both natural and induced - is extremely important for increasing permeability in otherwise low-permeability rock. We analyze natural extension fracture networks within a complete measured outcrop section of the Ernst Member of the Boquillas Formation in Big Bend National Park, west Texas. Results of bed-center, dip-parallel scanline surveys demonstrate nearly identical fracture strikes and slight variation in dip between mudrock, chalk, and limestone beds. Fracture spacing tends to increase proportional to bed thickness in limestone and chalk beds; however, dramatic differences in fracture spacing are observed in mudrock. A direct relationship is observed between fracture spacing/thickness ratio and rock competence. Vertical fracture penetrations measured from the middle of chalk and limestone beds generally extend to and often beyond bed boundaries into the vertically adjacent mudrock beds. In contrast, fractures in the mudrock beds rarely penetrate beyond the bed boundaries into the adjacent carbonate beds. Consequently, natural bed-perpendicular fracture connectivity through the mechanically layered sequence generally is poor. Fracture connectivity strongly influences permeability architecture, and fracture prediction should consider thin bed-scale control on fracture heights and the strong lithologic control on fracture spacing.

  10. The "Admissions" Side of BCCAT: An Update. Special Report

    ERIC Educational Resources Information Center

    British Columbia Council on Admissions and Transfer, 2008

    2008-01-01

    To spearhead increased emphasis on admissions, the British Columbia Council on Admissions and Transfer (BCCAT) formed an Admissions Committee in Fall 2003. The committee recognized the importance of institutional autonomy in determining admissions policies and processes at each institution. Following initiation of the Student Transitions Project…

  11. Mechanical and dosimetric quality control for computer controlled radiotherapy treatment equipment.

    PubMed

    Thompson, A V; Lam, K L; Balter, J M; McShan, D L; Martel, M K; Weaver, T A; Fraass, B A; Ten Haken, R K

    1995-05-01

    Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

    1995-01-01

    Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed

  13. Nonlinear dynamics and the nano-mechanical control of electrons in crystalline solids. Nano-mechanical control of electrons

    NASA Astrophysics Data System (ADS)

    Velarde, M. G.

    2016-09-01

    Under the umbrella of nano-mechanical control of electrons in crystalline solids, provided here are i) a discussion of aspects of the influence of static piezoelectricity on semiconductors, ii) a description of electron surfing on traveling piezopotentials/surface acoustic waves, iii) comments on the role of solitons in (dopable) polymer conductors/synthetic metals, and iv) the major component of these notes, a discussion of basic aspects of lattice solitons and discrete breathers permitting to understand genuine electron surfing on nanosolitons. This surfing offers a form of long range, fast and robust transport process in crystalline solids. The particular case of the undopable highly crystalline polydiacetylene polymer serves to illustrate the invention of a novel solectron field effect transistor (SFET).

  14. Aquatic Plant Control Research Program. Simulated Mechanical Control of Aquatic Plants in Buffalo Lake, Wisconsin.

    DTIC Science & Technology

    1983-10-01

    eastern two thirds of the lake. The Aquamarine H8-650 and H-400 harvester were selected for simulation. Mechanical control operations were simulated in the...treatment area for the two summer periods using each harvester working alone and with a single Aquamarine T-650 transport unit. Surface-topped growth... Aquamarine Corporation have received the most widespread usage (Cannellos 1981). Aquamarine harvesters are owned by many contractors, governmental agencies

  15. Antibiotic prescribing and admissions with major suppurative complications of respiratory tract infections: a data linkage study.

    PubMed Central

    Little, Paul; Watson, Louise; Morgan, Stephen; Williamson, Ian

    2002-01-01

    BACKGROUND: Systematic reviews of antibiotic treatment of common acute respiratory tract infections (RTIs) suggest modest symptomatic benefit, but provide limited evidence that prescribing prevents complications. AIM: To assess the relationship between penicillin prescribing (the most commonly used group of antibiotics for RTIs) and hospital admission with complications. DESIGN OF STUDY: Data linkage study. SETTING: Ninety-six health authorities of England for the year 1997-1998. METHOD: Hospital admissions related to RTIs were linked with prescribing analysis and cost (PACT) data. RESULTS: There was close correlation between items of penicillin use and total antibiotic use (r = 0.96). After controlling for SMR, age, sex, and Townsend score, a one-unit increase in penicillin use (items dispensed per capita) was associated with a reduction in annual incidence per 10,000 of admissions for quinsy (-3.55 admissions, 95% confidence interval [CI] = -6.85 to -0.26), and mastoiditis (square root of incidence of admissions = -1.05, 95% CI = -1.82 to -0.27). This does not represent lower referral thresholds among higher prescribers as higher prescribing was associated with more admissions for tonsillectomy and overall admissions. Increasing prescribing by 2000 items of penicillin for a practice of 10,000 patients could possibly prevent one admission for either mastoiditis or quinsy. CONCLUSION: Higher antibiotic prescribing is associated with significantly fewer admissions with major complications. However, the overall size of the effect is modest and it is difficult to advocate an overall increase in prescribing to prevent complications. Future research should concentrate on finding better methods of targeting antibiotics to individuals at risk of poor outcome. PMID:12030660

  16. Assessing Practical Intelligence in Business School Admissions: A Supplement to the Graduate Management Admissions Test

    ERIC Educational Resources Information Center

    Hedlund, Jennifer; Wilt, Jeanne M.; Nebel, Kristina L.; Ashford, Susan J.; Sternberg, Robert J.

    2006-01-01

    The Graduate Management Admission Test (GMAT) is the most widely used measure of managerial potential in MBA admissions. GMAT scores, although predictive of grades in business school, leave much of the variance in graduate school performance unexplained. The GMAT also produces disparities in test scores between groups, generating the potential for…

  17. Major Research Efforts of the Law School Admission Council. Law School Admission Research.

    ERIC Educational Resources Information Center

    Hart, Frederick M.; Evans, Franklin R.

    Research conducted by the Law School Admission Council since the development of the Law School Admission Test (LSAT) in 1948 is described. An overview of the research topics is provided, and relevant published reports are cited in 61 footnotes. The following topics of study are discussed: (1) use and validity of traditional predictors of law…

  18. Multiple hospital admissions in a calendar year.

    PubMed

    Newton, J; Goldacre, M

    1993-09-01

    Hospital in-patient workload is routinely measured as episodes of care. We report on the extent to which counts of episodes of care differ from counts of patients treated in different specialties and in different age groups. Linked records of hospital care in a population of 1.9 million people, collected over an 11-year period (1976-1986), were analysed. The all-ages multiple admission ratio (the number of admissions per 100 people admitted in the same specialty and year) varied between specialties from 102 to 171. Medical specialties tended to have higher ratios than surgical ones. The influence of age on multiple admission ratios varied between specialties, although in general the ratios increased with increasing age. There were progressive but small increases in multiple admission ratios over the period studied in a number of specialties but, by and large, stability over time was more striking than any change. The information presented could be used to estimate person-based admission rates from available episode-based data where the former are not available. This should be helpful both in managing hospital resources and in purchasing care on behalf of resident populations. Purchasers in particular should be aware of numbers of people being treated as well as the numbers of episodes of care provided.

  19. Cell cycle control, checkpoint mechanisms, and genotoxic stress.

    PubMed Central

    Shackelford, R E; Kaufmann, W K; Paules, R S

    1999-01-01

    The ability of cells to maintain genomic integrity is vital for cell survival and proliferation. Lack of fidelity in DNA replication and maintenance can result in deleterious mutations leading to cell death or, in multicellular organisms, cancer. The purpose of this review is to discuss the known signal transduction pathways that regulate cell cycle progression and the mechanisms cells employ to insure DNA stability in the face of genotoxic stress. In particular, we focus on mammalian cell cycle checkpoint functions, their role in maintaining DNA stability during the cell cycle following exposure to genotoxic agents, and the gene products that act in checkpoint function signal transduction cascades. Key transitions in the cell cycle are regulated by the activities of various protein kinase complexes composed of cyclin and cyclin-dependent kinase (Cdk) molecules. Surveillance control mechanisms that check to ensure proper completion of early events and cellular integrity before initiation of subsequent events in cell cycle progression are referred to as cell cycle checkpoints and can generate a transient delay that provides the cell more time to repair damage before progressing to the next phase of the cycle. A variety of cellular responses are elicited that function in checkpoint signaling to inhibit cyclin/Cdk activities. These responses include the p53-dependent and p53-independent induction of Cdk inhibitors and the p53-independent inhibitory phosphorylation of Cdk molecules themselves. Eliciting proper G1, S, and G2 checkpoint responses to double-strand DNA breaks requires the function of the Ataxia telangiectasia mutated gene product. Several human heritable cancer-prone syndromes known to alter DNA stability have been found to have defects in checkpoint surveillance pathways. Exposures to several common sources of genotoxic stress, including oxidative stress, ionizing radiation, UV radiation, and the genotoxic compound benzo[a]pyrene, elicit cell cycle

  20. Catalytic Synthesis of Oxygenates: Mechanisms, Catalysts and Controlling Characteristics

    SciTech Connect

    Klier, Kamil; Herman, Richard G

    2005-11-30

    This research focused on catalytic synthesis of unsymmetrical ethers as a part of a larger program involving oxygenated products in general, including alcohols, ethers, esters, carboxylic acids and their derivatives that link together environmentally compliant fuels, monomers, and high-value chemicals. The catalysts studied here were solid acids possessing strong Brnsted acid functionalities. The design of these catalysts involved anchoring the acid groups onto inorganic oxides, e.g. surface-grafted acid groups on zirconia, and a new class of mesoporous solid acids, i.e. propylsulfonic acid-derivatized SBA-15. The former catalysts consisted of a high surface concentration of sulfate groups on stable zirconia catalysts. The latter catalyst consists of high surface area, large pore propylsulfonic acid-derivatized silicas, specifically SBA-15. In both cases, the catalyst design and synthesis yielded high concentrations of acid sites in close proximity to one another. These materials have been well-characterization in terms of physical and chemical properties, as well as in regard to surface and bulk characteristics. Both types of catalysts were shown to exhibit high catalytic performance with respect to both activity and selectivity for the bifunctional coupling of alcohols to form ethers, which proceeds via an efficient SN2 reaction mechanism on the proximal acid sites. This commonality of the dual-site SN2 reaction mechanism over acid catalysts provides for maximum reaction rates and control of selectivity by reaction conditions, i.e. pressure, temperature, and reactant concentrations. This research provides the scientific groundwork for synthesis of ethers for energy applications. The synthesized environmentally acceptable ethers, in part derived from natural gas via alcohol intermediates, exhibit high cetane properties, e.g. methylisobutylether with cetane No. of 53 and dimethylether with cetane No. of 55-60, or high octane properties, e.g. diisopropylether with

  1. Rheological controls on the terrestrial core formation mechanism

    NASA Astrophysics Data System (ADS)

    Golabek, G. J.; Gerya, G. V.; Tackley, P. J.

    2008-09-01

    Abstract Knowledge about the formation mechanism for the Earth's core is still very limited. The fracturing mechanism was proposed by [1] for cold central protocores surrounded by an iron layer, which develops from the overlying magma ocean. In this case the cold protocore is displaced from the centre of the accreting planet and fractured due to the large stresses, whereas the consideration of short-lived radioactive radioactive heating may result in warmer central regions and the preference of iron diapirism as core formation mechanism [2,3]. Until now most numerical models of core formation via diapirism were limited to the simulation of the sinking of a single diapir. We performed 2D spherical simulations using the code I2ELVIS applying the newly developed "spherical-Cartesian" methodology combining finite differences on a fully staggered rectangular Eulerian grid and Lagrangian marker-in-cell technique for solving momentum, continuity and temperature equations as well as Poisson equation for gravity potential in a self-gravitating planetary body [4]. In the model the planet is surrounded by a low viscosity (η=1019 Pa s), massless fluid ("sticky air") to simulate a free surface [5]. We applied a temperature and stress dependent viscoplastic rheology inside an Earth-sized planet and included heat release due to radioactive decay. As initial condition we use randomly distributed diapirs with random sizes in the range 50 to 100 km radius inside the accreting planet, which represent the iron delivered by predifferentiated impactors. A systematic investigation of the diapir behaviour for different activation volumes and yield stresses is being performed, and results are being compared to the isotopic time scale of core formation on terrestrial planets. We show that the rheology controls which formation mechanism becomes dominant. We observe 3 major regimes of core formation: First a weak viscous protocore for low activation volumes and low yield stress, which is

  2. Impact of tornadoes on hospital admissions for acute cardiovascular events

    PubMed Central

    Silva-Palacios, Federico; Casanegra, Ana Isabel; Shapiro, Alan; Phan, Minh; Hawkins, Beau; Li, Ji; Stoner, Julie; Tafur, Alfonso

    2016-01-01

    Background There is a paucity of data describing cardiovascular events after tornado outbreaks. We proposed to study the effects of tornadoes on the incidence of cardiovascular events at a tertiary care institution. Population and methods Hospital admission records from a single center situated in a tornado-prone area three months before and after a 2013 tornado outbreak were abstracted. To control for seasonal variation, we also abstracted data from the same period of the prior year (control). Hospital admissions for cardiovascular events (CVEs) including acute myocardial infarction, stroke and venous thromboembolism (VTE) were summated by zip codes, and compared by time period. Results There were 22,607 admissions analyzed, of which 6,705 (30%), 7,980 (35%), and 7,922 (35%) were during the pre-tornado, post-tornado, and control time frames, respectively. There were 344 CVE in the controls, 317 CVE in pre-tornado and 364 CVEs in post tornado periods. There was no difference in the prevalence of CVE during the post-tornado season compared with the control (PPR = 1.05 95% CI: 0.91 to 1.21, p = 0.50) or the pre-tornado season (PPR= 0.96, 95% CI: 0.83 to 1.21, p = 0.63). Conclusion In conclusion, tornado outbreaks did not increase the prevalence of cardiovascular events. In contrast to the effect of hurricanes, implementation of a healthcare policy change directed toward the early treatment and prevention of cardiovascular events after tornadoes does not seem warranted. PMID:26388119

  3. Connections among several chaos feedback control approaches and chaotic vibration control of mechanical systems

    NASA Astrophysics Data System (ADS)

    Yang, Dixiong; Zhou, Jilei

    2014-11-01

    This study reveals the essential connections among several popular chaos feedback control approaches, such as delayed feedback control (DFC), stability transformation method (STM), adaptive adjustment method (AAM), parameter adjustment method, relaxed Newton method, and speed feedback control method (SFCM), etc. Meanwhile, the generality and practical applicability of these approaches are evaluated and compared. It is shown that for discrete chaotic maps, STM can be regarded as a kind of predictive feedback control, and AAM is actually a special case of STM which is merely effective for a particular dynamical system. The parameter adjustment method is only a different expression of the relaxed Newton method, and both of them represent just one search direction of STM, i.e., the gradient direction. Moreover, the intrinsic relation between the STM and SFCM for controlling the equilibrium of continuous autonomous systems is investigated, indicating that STM can be viewed as a special form of the SFCM. Finally, both the STM and SFCM are extended to control the chaotic vibrations of non-autonomous mechanical systems effectively.

  4. [Medical examination prior to trade school admission].

    PubMed

    Hursidić-Radulović, Azra; Decković-Vukres, Vlasta

    2005-01-01

    Regulation on medical examination prior to apprenticeship is built in the Act on Trades and Crafts. Medical examinations of the students before admission to secondary craft schools have been done regularly since 1993. Between 11,000 and 14,000 students are admitted to secondary craft schools in the Republic of Croatia annually. According to statistics, about 10% of students have obvious health problems, about 5% of students have healt problems which vitally limit their capacity in particular crafts. This statistic refers to about 3% of the examined students. Medical examinations of students prior to admission to craft schools represent a particular sort of health capacity examinations. The paper includes applications for the most freqent trades and crafts, and findings of the craft school admission examinations.

  5. [Involuntary admission of addict during early pregnancy].

    PubMed

    Hondius, Adger J K; Stikker, Tineke E; Wennink, J M B Hanneke; Honig, Adriaan

    2012-01-01

    A 30-year-old cocaine-dependent woman was 16 weeks pregnant. Because of possible endangerment of the fetus, an involuntary provisional admission was authorized. Of particular interest is the application of the Dutch Act on Formal Admissions to Psychiatric Hospitals for the primary diagnosis 'addiction' and the fact that the fetus was regarded as a legal 'other'. In severe cases of addiction combined with pregnancy an earlier intervention is needed and arrangement of accelerated legal custody of the newborn before birth should be considered. For the protection of the unborn, we advocate a stricter application of the United Nations Convention on the Rights of the Child. Information for addicted women with preconception counselling can help prevent a compulsory admission.

  6. Neural conflict-control mechanisms improve memory for target stimuli.

    PubMed

    Krebs, Ruth M; Boehler, Carsten N; De Belder, Maya; Egner, Tobias

    2015-03-01

    According to conflict-monitoring models, conflict serves as an internal signal for reinforcing top-down attention to task-relevant information. While evidence based on measures of ongoing task performance supports this idea, implications for long-term consequences, that is, memory, have not been tested yet. Here, we evaluated the prediction that conflict-triggered attentional enhancement of target-stimulus processing should be associated with superior subsequent memory for those stimuli. By combining functional magnetic resonance imaging (fMRI) with a novel variant of a face-word Stroop task that employed trial-unique face stimuli as targets, we were able to assess subsequent (incidental) memory for target faces as a function of whether a given face had previously been accompanied by congruent, neutral, or incongruent (conflicting) distracters. In line with our predictions, incongruent distracters not only induced behavioral conflict, but also gave rise to enhanced memory for target faces. Moreover, conflict-triggered neural activity in prefrontal and parietal regions was predictive of subsequent retrieval success, and displayed conflict-enhanced functional coupling with medial-temporal lobe regions. These data provide support for the proposal that conflict evokes enhanced top-down attention to task-relevant stimuli, thereby promoting their encoding into long-term memory. Our findings thus delineate the neural mechanisms of a novel link between cognitive control and memory.

  7. Mitochondrial Protein Quality Control: The Mechanisms Guarding Mitochondrial Health

    PubMed Central

    Bohovych, Iryna; Chan, Sherine S.L.

    2015-01-01

    Abstract Significance: Mitochondria are complex dynamic organelles pivotal for cellular physiology and human health. Failure to maintain mitochondrial health leads to numerous maladies that include late-onset neurodegenerative diseases and cardiovascular disorders. Furthermore, a decline in mitochondrial health is prevalent with aging. A set of evolutionary conserved mechanisms known as mitochondrial quality control (MQC) is involved in recognition and correction of the mitochondrial proteome. Recent Advances: Here, we review current knowledge and latest developments in MQC. We particularly focus on the proteolytic aspect of MQC and its impact on health and aging. Critical Issues: While our knowledge about MQC is steadily growing, critical gaps remain in the mechanistic understanding of how MQC modules sense damage and preserve mitochondrial welfare, particularly in higher organisms. Future Directions: Delineating how coordinated action of the MQC modules orchestrates physiological responses on both organellar and cellular levels will further elucidate the current picture of MQC's role and function in health, cellular stress, and degenerative diseases. Antioxid. Redox Signal. 22, 977–994. PMID:25546710

  8. Weathering controls on mechanisms of carbon storage in grassland soils

    USGS Publications Warehouse

    Masiello, C.A.; Chadwick, O.A.; Southon, J.; Torn, M.S.; Harden, J.W.

    2004-01-01

    On a sequence of soils developed under similar vegetation, temperature, and precipitation conditions, but with variations in mineralogical properties, we use organic carbon and 14C inventories to examine mineral protection of soil organic carbon. In these soils, 14C data indicate that the creation of slow-cycling carbon can be modeled as occurring through reaction of organic ligands with Al3+ and Fe3+ cations in the upper horizons, followed by sorption to amorphous inorganic Al compounds at depth. Only one of these processes, the chelation Al3+ and Fe3+ by organic ligands, is linked to large carbon stocks. Organic ligands stabilized by this process traverse the soil column as dissolved organic carbon (both from surface horizons and root exudates). At our moist grassland site, this chelation and transport process is very strongly correlated with the storage and long-term stabilization of soil organic carbon. Our 14C results show that the mechanisms of organic carbon transport and storage at this site follow a classic model previously believed to only be significant in a single soil order (Spodosols), and closely related to the presence of forests. The presence of this process in the grassland Alfisol, Inceptisol, and Mollisol soils of this chronosequence suggests that this process is a more significant control on organic carbon storage than previously thought. Copyright 2004 by the American Geophysical Union.

  9. Adrenergic receptor control mechanism for growth hormone secretion.

    PubMed

    Blackard, W G; Heidingsfelder, S A

    1968-06-01

    The influence of catecholamines on growth hormone secretion has been difficult to establish previously, possibly because of the suppressive effect of the induced hyperglycemia on growth hormone concentrations. In this study, an adrenergic receptor control mechanism for human growth hormone (HGH) secretion was uncovered by studying the effects of alpha and beta receptor blockade on insulin-induced growth hormone elevations in volunteer subjects. Alpha adrenergic blockade with phentolamine during insulin hypoglycemia, 0.1 U/kg, inhibited growth hormon elevations to 30-50% of values in the same subjects during insulin hypoglycemia without adrenergic blockade. More complete inhibition by phentolamine could not be demonstrated at a lower dose of insulin (0.05 U/kg). Beta adrenergic blockade with propranolol during insulin hypoglycemia significantly enhanced HGH concentrations in paired experiments. The inhibiting effect of alpha adrenergic receptor blockade on HGH concentrations could not be attributed to differences in blood glucose or free fatty acid values; however, more prolonged hypoglycemia and lower plasma free fatty acid values may have been a factor in the greater HGH concentrations observed during beta blockade. In the absence of insulin induced hypoglycemia, neither alpha nor beta adrenergic receptor blockade had a detectable effect on HGH concentrations. Theophylline, an inhibitor of cyclic 3'5'-AMP phosphodiesterase activity, also failed to alter plasma HGH concentrations. These studies demonstrate a stimulatory effect of alpha receptors and a possible inhibitory effect of beta receptors on growth hormone secretion.

  10. Controlled growth mechanism of poly (3-hexylthiophene) nanowires

    NASA Astrophysics Data System (ADS)

    Kiymaz, D.; Yagmurcukardes, M.; Tomak, A.; Sahin, H.; Senger, R. T.; Peeters, F. M.; Zareie, H. M.; Zafer, C.

    2016-11-01

    Synthesis of 1D-polymer nanowires by a self-assembly method using marginal solvents is an attractive technique. While the formation mechanism is poorly understood, this method is essential in order to control the growth of nanowires. Here we visualized the time-dependent assembly of poly (3-hexyl-thiophene-2,5-diyl) (P3HT) nanowires by atomic force microscopy and scanning tunneling microscopy. The assembly of P3HT nanowires was carried out at room temperature by mixing cyclohexanone (CHN), as a poor solvent, with polymer solution in 1,2-dichlorobenzene (DCB). Both π-π stacking and planarization, obtained at the mix volume ratio of P3HT (in DCB):CHN (10:7), were considered during the investigation. We find that the length of nanowires was determined by the ordering of polymers in the polymer repetition direction. Additionally, our density functional theory calculations revealed that the presence of DCB and CHN molecules that stabilize the structural distortions due to tail group of polymers was essential for the core-wire formation.

  11. Weathering controls on mechanisms of carbon storage in grassland soils

    SciTech Connect

    Masiello, C.A.; Chadwick, O.A.; Southon, J.; Torn, M.S.; Harden, J.W.

    2004-09-01

    On a sequence of soils developed under similar vegetation, temperature, and precipitation conditions, but with variations in mineralogical properties, we use organic carbon and 14C inventories to examine mineral protection of soil organic carbon. In these soils, 14C data indicate that the creation of slow-cycling carbon can be modeled as occurring through reaction of organic ligands with Al3+ and Fe3+ cations in the upper horizons, followed by sorption to amorphous inorganic Al compounds at depth. Only one of these processes, the chelation of Al3+ and Fe3+ by organic ligands, is linked to large carbon stocks. Organic ligands stabilized by this process traverse the soil column as dissolved organic carbon (both from surface horizons and root exudates). At our moist grassland site, this chelation and transport process is very strongly correlated with the storage and long-term stabilization of soil organic carbon. Our 14C results show that the mechanisms of organic carbon transport and storage at this site follow a classic model previously believed to only be significant in a single soil order (Spodosols), and closely related to the presence of forests. The presence of this process in the grassland Alfisol, Inceptisol, and Mollisol soils of this chronosequence suggests that this process is a more significant control on organic carbon storage than previously thought.

  12. Molecular mechanisms controlling CFTR gene expression in the airway

    PubMed Central

    Zhang, Zhaolin; Ott, Christopher J; Lewandowska, Marzena A; Leir, Shih-Hsing; Harris, Ann

    2012-01-01

    Abstract The low levels of CFTR gene expression and paucity of CFTR protein in human airway epithelial cells are not easily reconciled with the pivotal role of the lung in cystic fibrosis pathology. Previous data suggested that the regulatory mechanisms controlling CFTR gene expression might be different in airway epithelium in comparison to intestinal epithelium where CFTR mRNA and protein is much more abundant. Here we examine chromatin structure and modification across the CFTR locus in primary human tracheal (HTE) and bronchial (NHBE) epithelial cells and airway cell lines including 16HBE14o- and Calu3. We identify regions of open chromatin that appear selective for primary airway epithelial cells and show that several of these are enriched for a histone modification (H3K4me1) that is characteristic of enhancers. Consistent with these observations, three of these sites encompass elements that have cooperative enhancer function in reporter gene assays in 16HBE14o- cells. Finally, we use chromosome conformation capture (3C) to examine the three-dimensional structure of nearly 800 kb of chromosome 7 encompassing CFTR and observe long-range interactions between the CFTR promoter and regions far outside the locus in cell types that express high levels of CFTR. PMID:21895967

  13. Immunosensor with fluid control mechanism for salivary cortisol analysis.

    PubMed

    Yamaguchi, Masaki; Matsuda, Yohei; Sasaki, Shohei; Sasaki, Makoto; Kadoma, Yoshihiro; Imai, Yoshikatsu; Niwa, Daisuke; Shetty, Vivek

    2013-03-15

    The purpose of this research is to demonstrate a new design for a cortisol immunosensor for the noninvasive and quantitative analysis of salivary cortisol. We propose a cortisol immunosensor with a fluid control mechanism which has both a vertical flow and a lateral flow. The detected current resulting from a competitive reaction between the sample cortisol and a glucose oxidase (GOD)-labeled cortisol conjugate was found to be inversely related to the concentration of cortisol in the sample solution. A calibration curve using the relative detected current showed a R(2)=0.98 and CV=14% for a range of standard cortisol solutions corresponding to the concentrations of native salivary cortisol (0.1-10 ng/ml). The measurement could be accomplished within 35 min and the cortisol immunosensor could be reused. These results show promise for realizing an on-site and easy-to-use biosensor for cortisol. Used for evaluation of human salivary cortisol levels, the cortisol immunosensor measurement corresponded closely with commercially available ELISA method (R(2)=0.92). Our results indicate the promise of the new cortisol immunosensor for noninvasive, point of care measurement of human salivary cortisol levels.

  14. Geometrical and Mechanical Properties Control Actin Filament Organization

    PubMed Central

    Ennomani, Hajer; Théry, Manuel; Nedelec, Francois; Blanchoin, Laurent

    2015-01-01

    The different actin structures governing eukaryotic cell shape and movement are not only determined by the properties of the actin filaments and associated proteins, but also by geometrical constraints. We recently demonstrated that limiting nucleation to specific regions was sufficient to obtain actin networks with different organization. To further investigate how spatially constrained actin nucleation determines the emergent actin organization, we performed detailed simulations of the actin filament system using Cytosim. We first calibrated the steric interaction between filaments, by matching, in simulations and experiments, the bundled actin organization observed with a rectangular bar of nucleating factor. We then studied the overall organization of actin filaments generated by more complex pattern geometries used experimentally. We found that the fraction of parallel versus antiparallel bundles is determined by the mechanical properties of actin filament or bundles and the efficiency of nucleation. Thus nucleation geometry, actin filaments local interactions, bundle rigidity, and nucleation efficiency are the key parameters controlling the emergent actin architecture. We finally simulated more complex nucleation patterns and performed the corresponding experiments to confirm the predictive capabilities of the model. PMID:26016478

  15. Geometrical and mechanical properties control actin filament organization.

    PubMed

    Letort, Gaëlle; Politi, Antonio Z; Ennomani, Hajer; Théry, Manuel; Nedelec, Francois; Blanchoin, Laurent

    2015-05-01

    The different actin structures governing eukaryotic cell shape and movement are not only determined by the properties of the actin filaments and associated proteins, but also by geometrical constraints. We recently demonstrated that limiting nucleation to specific regions was sufficient to obtain actin networks with different organization. To further investigate how spatially constrained actin nucleation determines the emergent actin organization, we performed detailed simulations of the actin filament system using Cytosim. We first calibrated the steric interaction between filaments, by matching, in simulations and experiments, the bundled actin organization observed with a rectangular bar of nucleating factor. We then studied the overall organization of actin filaments generated by more complex pattern geometries used experimentally. We found that the fraction of parallel versus antiparallel bundles is determined by the mechanical properties of actin filament or bundles and the efficiency of nucleation. Thus nucleation geometry, actin filaments local interactions, bundle rigidity, and nucleation efficiency are the key parameters controlling the emergent actin architecture. We finally simulated more complex nucleation patterns and performed the corresponding experiments to confirm the predictive capabilities of the model.

  16. Wetting mechanisms of gel-based controlled-release fertilizers.

    PubMed

    Shavit, U; Reiss, M; Shaviv, A

    2003-02-14

    The release mechanism of gel-based controlled release fertilizers (CRFs) involves water penetration into dry mixtures of fertilizers and gel forming polymers. Water penetration provides an upper limit to the whole release process. Where wetting prediction is often based on models that describe the flow of the liquid phase, vapor motion may become significant when a sharp wetting front exists. In this study we examine the role of vapor and fluid flows in the wetting process of CRFs consisting of urea or KNO(3) mixed with polyacrylamide (PAM). Vapor adsorption isotherms were obtained for typical fertilizer-PAM mixtures. Wetting and release experiments were conducted by dividing the CRFs into regions alternately filled with a pure fertilizer and mixtures of PAM and fertilizer. The experiments were designed in such a way that when the wetting front reaches a mixtures interface, its motion depends on the gradient imposed by the difference in osmotic potential (OP). The coupled equations of vapor and liquid flow in initially dry conditions were solved numerically to demonstrate the conceptual understanding gained by the experiments. The results show that wetting front motion is affected by transport and adsorption of vapor. It was also shown that the release rate is different when wetting is governed by vapor flow or by liquid flow. The release pattern from a multi-regions device was consistent with the wetting pattern, demonstrating the possibility to tailor the release according to periods of peak demand.

  17. Controlling mechanisms of moisture diffusion in convective drying of leather

    NASA Astrophysics Data System (ADS)

    Benmakhlouf, Naima; Azzouz, Soufien; Monzó-Cabrera, Juan; Khdhira, Hechmi; ELCafsi, Afif

    2016-08-01

    Leather manufacturing involves a crucial energy-intensive drying stage in the finishing process to remove its residual moisture. It occurs several times in the tanning course. As it is the target of this paper to depict an experimental way to determine moisture diffusion in the convective drying of leather. The effective diffusion coefficient is estimated by a method derived from Fick's law and by analytic method. The effective diffusion coefficients are obtained from drying tests and the diffusivity behaviour is studied versus the controlling parameter such as the convective airflow temperature. The experiments were conducted at hot air temperatures of 40, 45, 50, 55 and 60 °C and hot air speed of 1 m/s. The hot air temperature had significant effect on the effective moisture diffusivity of the leather sample. The average effective moisture diffusivity in rosehip ranged between 5.87 × 10-11 and 14.48 × 10-11 m2/s for leather at the temperatures studied. Activation energy for convective drying was found to be 38.46 kJ/mol for leather. The obtained results fully confirm the theoretical study in which an exponentially increasing relationship between effective diffusivity and temperature is predicted. The results of this study provide a better understanding of the drying mechanisms and may lead to a series of recommendations for leather drying optimization. It opens the possibility for further investigations on the description of drying conditions.

  18. Mechanisms that control knox gene expression in the Arabidopsis shoot.

    PubMed

    Ori, N; Eshed, Y; Chuck, G; Bowman, J L; Hake, S

    2000-12-01

    Knotted1-like homeobox (knox) genes are expressed in specific patterns within shoot meristems and play an important role in meristem maintenance. Misexpression of the knox genes, KNAT1 or KNAT2, in Arabidopsis produces a variety of phenotypes, including lobed leaves and ectopic stipules and meristems in the sinus, the region between lobes. We sought to determine the mechanisms that control knox gene expression in the shoot by examining recessive mutants that share phenotypic characteristics with 35S::KNAT1 plants. Double mutants of serrate (se) with either asymmetric1 (as1) or asymmetric2 (as2) showed lobed leaves, ectopic stipules in the sinuses and defects in the timely elongation of sepals, petals and stamens, similar to 35S::KNAT1 plants. Ectopic stipules and in rare cases, ectopic meristems, were detected in the sinuses on plants that were mutant for pickle and either as1 or as2. KNAT1 and KNAT2 were misexpressed in the leaves and flowers of single as1 and as2 mutants and in the sinuses of leaves of the different double mutants, but not in se or pickle single mutants. These results suggest that AS1 and AS2 promote leaf differentiation through repression of knox expression in leaves, and that SE and PKL globally restrict the competence to respond to genes that promote morphogenesis.

  19. Mechanics and control of the cytoskeleton in Amoeba proteus.

    PubMed Central

    Dembo, M

    1989-01-01

    Many models of the cytoskeletal motility of Amoeba proteus can be formulated in terms of the theory of reactive interpenetrating flow (Dembo and Harlow, 1986). We have devised numerical methodology for testing such models against the phenomenon of steady axisymmetric fountain flow. The simplest workable scheme revealed by such tests (the minimal model) is the main preoccupation of this study. All parameters of the minimal model are determined from available data. Using these parameters the model quantitatively accounts for the self assembly of the cytoskeleton of A. proteus: for the formation and detailed morphology of the endoplasmic channel, the ectoplasmic tube, the uropod, the plasma gel sheet, and the hyaline cap. The model accounts for the kinematics of the cytoskeleton: the detailed velocity field of the forward flow of the endoplasm, the contraction of the ectoplasmic tube, and the inversion of the flow in the fountain zone. The model also gives a satisfactory account of measurements of pressure gradients, measurements of heat dissipation, and measurements of the output of useful work by amoeba. Finally, the model suggests a very promising (but still hypothetical) continuum formulation of the free boundary problem of amoeboid motion. by balancing normal forces on the plasma membrane as closely as possible, the minimal model is able to predict the turgor pressure and surface tension of A. proteus. Several dynamical factors are crucial to the success of the minimal model and are likely to be general features of cytoskeletal mechanics and control in amoeboid cells. These are: a constitutive law for the viscosity of the contractile network that includes an automatic process of gelation as the network density gets large; a very vigorous cycle of network polymerization and depolymerization (in the case of A. proteus, the time constant for this reaction is approximately 12 s); control of network contractility by a diffusible factor (probably calcium ion); and

  20. Do health checks for adults with intellectual disability reduce emergency hospital admissions? Evaluation of a natural experiment

    PubMed Central

    Hosking, Fay J; Harris, Tess; DeWilde, Stephen; Beighton, Carole; Shah, Sunil M; Cook, Derek G

    2017-01-01

    Background Annual health checks for adults with intellectual disability (ID) have been incentivised by National Health Service (NHS) England since 2009, but it is unclear what impact they have had on important health outcomes such as emergency hospitalisation. Methods An evaluation of a ‘natural experiment’, incorporating practice and individual-level designs, to assess the effectiveness of health checks for adults with ID in reducing emergency hospital admissions using a large English primary care database. For practices, changes in admission rates for adults with ID between 2009–2010 and 2011–2012 were compared in 126 fully participating versus 68 non-participating practices. For individuals, changes in admission rates before and after the first health check for 7487 adults with ID were compared with 46 408 age-sex-practice matched controls. Incident rate ratios (IRRs) comparing changes in admission rates are presented for: all emergency, preventable emergency (for ambulatory care sensitive conditions (ACSCs)) and elective emergency. Results Practices with high health check participation showed no change in emergency admission rate among patients with ID over time compared with non-participating practices (IRR=0.97, 95% CI 0.78 to 1.19), but emergency admissions for ACSCs did fall (IRR=0.74, 0.58 to 0.95). Among individuals with ID, health checks had no effect on overall emergency admissions compared with controls (IRR=0.96, 0.87 to 1.07), although there was a relative reduction in emergency admissions for ACSCs (IRR=0.82, 0.69 to 0.99). Elective admissions showed no change with health checks in either analysis. Conclusions Annual health checks in primary care for adults with ID did not alter overall emergency admissions, but they appeared influential in reducing preventable emergency admissions. PMID:27312249

  1. Mechanical Engineering Design Project report: Enabler control systems

    NASA Technical Reports Server (NTRS)

    Cullen, Christian; Delvecchio, Dave; Scarborough, Alan; Havics, Andrew A.

    1992-01-01

    The Controls Group was assigned the responsibility for designing the Enabler's control system. The requirement for the design was that the control system must provide a simple user interface to control the boom articulation joints, chassis articulation joints, and the wheel drive. The system required controlling hydraulic motors on the Enabler by implementing 8-bit microprocessor boards. In addition, feedback to evaluate positions and velocities must be interfaced to provide the operator with confirmation as well as control.

  2. Selection Methods for Undergraduate Admissions in Australia. Does the Australian Predominate Entry Scheme the Australian Tertiary Admissions Rank (ATAR) Have a Future?

    ERIC Educational Resources Information Center

    Blyth, Kathryn

    2014-01-01

    This article considers the Australian entry score system, the Australian Tertiary Admissions Rank (ATAR), and its usage as a selection mechanism for undergraduate places in Australian higher education institutions and asks whether its role as the main selection criterion will continue with the introduction of demand driven funding in 2012.…

  3. Compositional, mechanical and hydrologic controls on fault slip behavior

    NASA Astrophysics Data System (ADS)

    Ikari, Matt J.

    In order to examine the roles of a variety of factors that are likely important in regulating the occurrence or lack of seismic slip, I evaluate the results of numerous laboratory studies of fault behavior, focusing on the effects of fault mineralogy, mechanical effects, and interactions between fluids and faulting processes. More specifically, these experiments are designed to investigate the underlying mechanisms controlling the transition from aseismic slip at shallow levels in the crust to seismic slip at depth, known as the updip limit of the seismogenic zone. Results of laboratory experiments indicate that mineralogy of fault gouge is a major control on fault behavior. The clay mineral montmorillonite (smectite) has been noted for its potential effect on seismogenesis in subduction zones (as well as all faults in general) due to its ability to take up water in its crystal structure. Dehydration of montmorillonite tends to increase its frictional strength as well as increase its propensity for seismic slip, as documented by a decrease in the frictional velocity dependence parameter a-b. However, the observed decrease in a-b is assisted by both increasing relative quartz percentage and increasing normal stress, implying that the onset of seismic behavior with increasing depth should not be attributed solely to smectite dehydration. Furthermore, clay-rich gouges in general, including those consisting of montmorillonite, illite, and chlorite, are both frictionally weak (mu < 0.35) and velocity-strengthening (frictionally stable, a-b > 0) at fluid-saturated conditions and effective normal stresses up to ˜60 MPa. Sheared gouges may also exhibit low fault-perpendicular permeability (k < 1x10-18), making them candidates to host high pore pressure. This indicates that faults containing granular, clay-rich gouges are unlikely to show seismic behavior, due their velocity-strengthening nature and stabilizing hydro-mechanical effects resulting from low permeability. In

  4. A unified control framework of the non-regular dynamics of mechanical oscillators

    NASA Astrophysics Data System (ADS)

    Lenci, S.; Rega, G.

    2004-12-01

    A method for controlling non-linear dynamics and chaos based on avoiding homo/heteroclinic bifurcations is considered in a unified framework. Various non-linear oscillators, both hardening and softening, symmetric and asymmetric, considered as archetypes of a more general class of single-d.o.f. systems, are analyzed. The Melnikov's method is applied to analytically detect the homo/heteroclinic bifurcations, and the results are used to select the optimal shape of the excitation permitting the maximum shift of the undesired bifurcations in parameter space. The generic character of the optimization problem is highlighted, and the problem itself is discussed in detail. Various control strategies are proposed, based on the elimination either of a single bifurcation (one-side controls) or of all bifurcations (global control). The optimization problems are solved, analytically and numerically, under various forms, by taking into account the physical admissibility of the related optimal excitation and the easiness of implementation in practical applications. It is shown that the solutions of one-side control problems are always system independent. In turn, the solutions of global control problems are system independent for the large class of (symmetric) systems considered in this work, although there are other systems whose solutions are system dependent. These considerations support the very generic nature of the optimal control.

  5. Paediatric admissions to the British military hospital at Camp Bastion, Afghanistan

    PubMed Central

    Arul, GS; Reynolds, J; DiRusso, S; Scott, A; Bree, S; Templeton, P; Midwinter, MJ

    2012-01-01

    INTRODUCTION International humanitarian law requires emergency medical support for both military personnel and civilians, including children. Here we present a detailed review of paediatric admissions with the pattern of injury and the resources they consume. METHODS All paediatric admissions to the hospital at Camp Bastion between 1 January and 29 April 2011 were analysed prospectively. Data collected included time and date of admission, patient age and weight, mechanism of injury, extent of wounding, treatment, length of hospital stay and discharge destination. RESULTS Eighty-five children (65 boys and 17 girls, median age: 8 years, median weight: 20kg) were admitted. In 63% of cases the indication for admission was battle related trauma and in 31% non-battle trauma. Of the blast injuries, 51% were due to improvised explosive devices. Non-battle emergencies were mainly due to domestic burns (46%) and road traffic accidents (29%). The most affected anatomical area was the extremities (44% of injuries). Over 30% of patients had critical injuries. Operative intervention was required in 74% of cases. The median time to theatre for all patients was 52 minutes; 3 patients with critical injuries went straight to theatre in a median of 7 minutes. A blood transfusion was required in 27 patients; 6 patients needed a massive transfusion. Computed tomography was performed on 62% of all trauma admissions and 40% of patients went to the intensive care unit. The mean length of stay was 2 days (range: 1–26 days) and there were 7 deaths. CONCLUSIONS Paediatric admissions make up a small but significant part of admissions to the hospital at Camp Bastion. The proportion of serious injuries is very high in comparison with admissions to a UK paediatric emergency department. The concentration of major injuries means that lessons learnt in terms of teamwork, the speed of transfer to theatre and massive transfusion protocols could be applied to UK paediatric practice. PMID:22524930

  6. Preoperative predictive factors for intensive care unit admission after pulmonary resection*

    PubMed Central

    Pinheiro, Liana; Santoro, Ilka Lopes; Perfeito, João Aléssio Juliano; Izbicki, Meyer; Ramos, Roberta Pulcheri; Faresin, Sonia Maria

    2015-01-01

    Objective: To determine whether the use of a set of preoperative variables can predict the need for postoperative ICU admission. Methods: This was a prospective observational cohort study of 120 patients undergoing elective pulmonary resection between July of 2009 and April of 2012. Prediction of ICU admission was based on the presence of one or more of the following preoperative characteristics: predicted pneumonectomy; severe/very severe COPD; severe restrictive lung disease; FEV1 or DLCO predicted to be < 40% postoperatively; SpO2 on room air at rest < 90%; need for cardiac monitoring as a precautionary measure; or American Society of Anesthesiologists physical status ≥ 3. The gold standard for mandatory admission to the ICU was based on the presence of one or more of the following postoperative characteristics: maintenance of mechanical ventilation or reintubation; acute respiratory failure or need for noninvasive ventilation; hemodynamic instability or shock; intraoperative or immediate postoperative complications (clinical or surgical); or a recommendation by the anesthesiologist or surgeon to continue treatment in the ICU. Results: Among the 120 patients evaluated, 24 (20.0%) were predicted to require ICU admission, and ICU admission was considered mandatory in 16 (66.6%) of those 24. In contrast, among the 96 patients for whom ICU admission was not predicted, it was required in 14 (14.5%). The use of the criteria for predicting ICU admission showed good accuracy (81.6%), sensitivity of 53.3%, specificity of 91%, positive predictive value of 66.6%, and negative predictive value of 85.4%. Conclusions: The use of preoperative criteria for predicting the need for ICU admission after elective pulmonary resection is feasible and can reduce the number of patients staying in the ICU only for monitoring. PMID:25750672

  7. Determination of functional prognosis in hospitalized patients following an intensive care admission

    PubMed Central

    Ferreira, Natália A; Lopes, Agnaldo José; Ferreira, Arthur S; Ntoumenopoulos, George; Dias, Jerffesson; Guimaraes, Fernando S

    2016-01-01

    AIM To investigate the factors associated with the functional progress of hospitalized patients following an intensive care admission. METHODS Retrospective study including data from a cohort of 198 hospitalized patients following an intensive care admission and not requiring mechanical ventilation in a single tertiary referral hospital. A generalized linear model was used to identify the main effects of clinical and demographic variables on the outcomes of functionality (KATZ Index of Independence in Activities of Daily Living) and muscle strength (MRC Scale). The covariates identified as independent predictors were analysed using the receiver operating characteristic curves. The analysis differentiated the periods in the intensive care unit (ICU), in the Ward (WARD) and the total time of hospital stay (TOT). RESULTS Considering the functional outcome (ΔKATZ), the variables that significantly contributed to the model (P < 0.05) were the KATZ and MRC on admission, age, sepsis (no), and total length of stay (TLS). Regarding the muscle strength outcome model (ΔMRC), the predictors were MRC on admission, Simplified Acute Physiology Score III, previous stroke, TLS, and sex (female). The variable age (AUC = 0.664) discriminated the ΔKATZICU. The variables age (AUC = 0.712), KATZ in ICU (AUC = 0.590) and on ward admission (AUC = 0.746), and MRC on ward admission (AUC = 0.721) were discriminative for ΔKATZWARD. For ΔKATZTOT the variables KATZ on ICU admission (AUC = 0.621) and TLS (AUC = 0.617) were discriminative. For ΔMRCICU the variables SAPSIII (AUC = 0.661) and MRC on ICU admission (AUC = 0.653) were discriminative. MRC on ICU (AUC = 0.681) and ward admission (AUC = 0.553) were discriminative for ΔMRCWARD. TLS (AUC = 0.649) and MRC on ward admission (AUC = 0.696) discriminative for the ΔMRCTOT. CONCLUSION Specific functional, clinical and demographical variables at ICU admission are associated with the functional prognosis during the hospitalization period

  8. The National Center Test for University Admissions

    ERIC Educational Resources Information Center

    Watanabe, Yoshinori

    2013-01-01

    This article describes the National Center Test for University Admissions, a unified national test in Japan, which is taken by 500,000 students every year. It states that implementation of the Center Test began in 1990, with the English component consisting only of the written section until 2005, when the listening section was first implemented…

  9. 34 CFR 106.15 - Admissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... higher education, and public institutions of undergraduate higher education. (e) Public institutions of undergraduate higher education. Subpart C does not apply to any public institution of undergraduate higher... 34 Education 1 2014-07-01 2014-07-01 false Admissions. 106.15 Section 106.15 Education...

  10. 34 CFR 106.15 - Admissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... higher education, and public institutions of undergraduate higher education. (e) Public institutions of undergraduate higher education. Subpart C does not apply to any public institution of undergraduate higher... 34 Education 1 2011-07-01 2011-07-01 false Admissions. 106.15 Section 106.15 Education...

  11. 34 CFR 106.15 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... higher education, and public institutions of undergraduate higher education. (e) Public institutions of undergraduate higher education. Subpart C does not apply to any public institution of undergraduate higher... 34 Education 1 2012-07-01 2012-07-01 false Admissions. 106.15 Section 106.15 Education...

  12. 34 CFR 106.15 - Admissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... higher education, and public institutions of undergraduate higher education. (e) Public institutions of undergraduate higher education. Subpart C does not apply to any public institution of undergraduate higher... 34 Education 1 2010-07-01 2010-07-01 false Admissions. 106.15 Section 106.15 Education...

  13. 34 CFR 106.15 - Admissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... higher education, and public institutions of undergraduate higher education. (e) Public institutions of undergraduate higher education. Subpart C does not apply to any public institution of undergraduate higher... 34 Education 1 2013-07-01 2013-07-01 false Admissions. 106.15 Section 106.15 Education...

  14. PREP: Outreach to Online Learners through Admissions

    ERIC Educational Resources Information Center

    Gupton, Preeti

    2016-01-01

    Librarians have collaborated with academic departments within their institutions for decades now, working with professors and administrators to bring information literacy skills to students. The librarians at National American University decided to extend this collaboration to a non-academic unit, the admissions department of the university. The…

  15. 18 CFR 1317.220 - Admissions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Admissions. 1317.220 Section 1317.220 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE...

  16. 18 CFR 1317.220 - Admissions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Admissions. 1317.220 Section 1317.220 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE...

  17. 18 CFR 1317.220 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Admissions. 1317.220 Section 1317.220 Conservation of Power and Water Resources TENNESSEE VALLEY AUTHORITY NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE...

  18. Open Admissions: The Pros and Cons.

    ERIC Educational Resources Information Center

    Barzun, Jacques; And Others

    The Council for Basic Education sponsored an all-day symposium on open admissions in 1971. This booklet contains the full text of the addresses given on that occasion, as well as the major part of the discussion among the panelists and answers to questions from the audience. The aim of the symposium was not only to provide information about…

  19. Foreign Language, the Classics, and College Admissions.

    ERIC Educational Resources Information Center

    LaFleur, Richard A.

    1993-01-01

    This article reports the results of a survey, funded by the American Classical League (ACL) and conducted during 1990-91, that assessed attitudes toward high school foreign-language study, in particular the study of Latin and Greek, in the college admissions process. (21 references) (VWL)

  20. Beyond Admission: The Challenge for Access.

    ERIC Educational Resources Information Center

    Roger, Angela; Sutherland, Margaret

    1992-01-01

    The Scottish Wider Access Programme (SWAP) aims to increase adults' access to higher education. Interviews with SWAP students and educators revealed that SWAP had been invaluable in preparing nontraditional students for admission to higher education. Issues include improving teaching methods geared toward mature students, providing support…

  1. The Admissions Criteria of Secondary Free Schools

    ERIC Educational Resources Information Center

    Morris, Rebecca

    2014-01-01

    This paper presents the results of an analysis of the admissions criteria used by the first two waves of secondary Free Schools in England. The type of criteria and their ranked order is explored and their potential impact on the school composition is considered. The findings demonstrate the diversity of criteria being used by this new type of…

  2. 15 CFR 8a.220 - Admissions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Admissions. 8a.220 Section 8a.220 Commerce and Foreign Trade Office of the Secretary of Commerce NONDISCRIMINATION ON THE BASIS OF SEX IN... institution. (c) Application of §§ 8a.300 through .310. Except as provided in paragraphs (d) and (e) of...

  3. Reporting Subscores from College Admission Tests

    ERIC Educational Resources Information Center

    Lyren, Per-Erik

    2009-01-01

    The added value of reporting subscores on a college admission test (SweSAT) was examined in this study. Using a CTT-derived objective method for determining the value of reporting subscores, it was concluded that there is added value in reporting section scores (Verbal/Quantitative) as well as subtest scores. These results differ from a study of…

  4. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Admission. 5.300 Section 5.300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

  5. 40 CFR 5.300 - Admission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Admission. 5.300 Section 5.300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of...

  6. "Stealth Applicants" Are Changing the Admissions Equation

    ERIC Educational Resources Information Center

    Hoover, Eric

    2008-01-01

    Jeff Rickey is a numbers guy. But three years ago, a colleague asked him about something he'd never counted: applicants who came out of nowhere. The question intrigued Mr. Rickey, dean of admissions and financial aid at Earlham College in Indiana. He found that 17 percent of the college's applicants that year had not called, taken a tour, or…

  7. 10 CFR 2.708 - Admissions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Admissions. 2.708 Section 2.708 Energy NUCLEAR REGULATORY COMMISSION RULES OF PRACTICE FOR DOMESTIC LICENSING PROCEEDINGS AND ISSUANCE OF ORDERS Rules for Formal... the request is directed serves on the requesting party either: (i) A sworn statement...

  8. EARLY SCHOOL ADMISSIONS PROJECT, PROMISING PRACTICES.

    ERIC Educational Resources Information Center

    Baltimore City Public Schools, MD.

    THE EXPERIMENTAL PROJECT ATTEMPTS TO DETERMINE WHETHER EARLY ADMISSION TO SCHOOL CAN OVERCOME BARRIERS TO LEARNING WHICH ENVIRONMENTAL FACTORS SEEM TO IMPOSE. A DEPRIVED CHILD OFTEN DOES NOT RECEIVE ATTENTION, AFFECTION, OR GUIDANCE WITHIN HIS HOME. THE YOUNG CHILD SHOULD BE HELPED TO DEVELOP A WHOLESOME SELF-CONCEPT, TO ACQUIRE THE DRIVE TO…

  9. Predicting Academic Success Using Admission Profiles

    ERIC Educational Resources Information Center

    Davidovitch, Nitza; Soen, Dan

    2015-01-01

    This study, conducted at a tertiary education institution in Israel, following two previous studies, was designed to deal again with a question that is a topic of debate in Israel and worldwide: Is there justification for the approach that considers restrictive university admission policies an efficient tool for predicting students' success at the…

  10. University Admissions. Policy Note. Number 3

    ERIC Educational Resources Information Center

    Group of Eight (NJ1), 2012

    2012-01-01

    University admissions, like many other aspects of the higher education sector, are going through a time of significant change. From 2012, universities will receive full funding under the Commonwealth Grants Scheme (CGS) for as many places as they offer. Previously, the Government limited the number of funded places, with a tolerance band for…

  11. Differential Prediction Generalization in College Admissions Testing

    ERIC Educational Resources Information Center

    Aguinis, Herman; Culpepper, Steven A.; Pierce, Charles A.

    2016-01-01

    We introduce the concept of "differential prediction generalization" in the context of college admissions testing. Specifically, we assess the extent to which predicted first-year college grade point average (GPA) based on high-school grade point average (HSGPA) and SAT scores depends on a student's ethnicity and gender and whether this…

  12. Electromagnetic energy coupling mechanism with matrix architecture control

    NASA Technical Reports Server (NTRS)

    Knowles, Gareth (Inventor); Hughes, Eli (Inventor)

    2006-01-01

    The present invention relates generally to reconfigurable, solid-state matrix arrays comprising multiple rows and columns of reconfigurable secondary mechanisms that are independently tuned. Specifically, the invention relates to reconfigurable devices comprising multiple, solid-state mechanisms characterized by at least one voltage-varied parameter disposed within a flexible, multi-laminate film, which are suitable for use as magnetic conductors, ground surfaces, antennas, varactors, ferrotunable substrates, or other active or passive electronic mechanisms.

  13. Development of an Outdoor Temperature-Based Control Algorithm for Residential Mechanical Ventilation Control

    SciTech Connect

    Less, Brennan; Walker, Iain; Tang, Yihuan

    2014-06-01

    Smart ventilation systems use controls to ventilate more during those periods that provide either an energy or IAQ advantage (or both) and less during periods that provide a dis advantage. Using detailed building simulations, this study addresses one of the simplest and lowest cost types of smart controllers —outdoor temperature- based control. If the outdoor temperature falls below a certain cut- off, the fan is simply turned off. T he main principle of smart ventilation used in this study is to shift ventilation from time periods with large indoor -outdoor temperature differences, to periods where these differences are smaller, and their energy impacts are expected to be less. Energy and IAQ performance are assessed relative to a base case of a continuously operated ventilation fan sized to comply with ASHRAE 62.2-2013 whole house ventilation requirements. In order to satisfy 62.2-2013, annual pollutant exposure must be equivalent between the temperature controlled and continuous fan cases. This requires ventilation to be greater than 62.2 requirements when the ventilation system operates. This is achieved by increasing the mechanical ventilation system air flow rates.

  14. Similar Motor Cortical Control Mechanisms for Precise Limb Control during Reaching and Locomotion

    PubMed Central

    Yakovenko, Sergiy

    2015-01-01

    Throughout the course of evolution there has been a parallel development of the complexity and flexibility of the nervous system and the skeletomuscular system that it controls. This development is particularly evident for the cerebral cortical areas and the transformation of the use of the upper limbs from a purely locomotor function to one including, or restricted to, reaching and grasping. This study addresses the issue of whether the control of reaching has involved the development of new cortical circuits or whether the same neurons are used to control both locomotion and reaching. We recorded the activity of pyramidal tract neurons in the motor cortex of the cat both during voluntary gait modifications and during reaching. All cells showed generally similar patterns of activity in both tasks. More specifically, we showed that, in many cases, cells maintained a constant temporal relationship to the activity of synergistic muscle groups in each task. In addition, in some cells the relationship between the intensity of the cell discharge activity and the magnitude of the EMG activity was equally constant during gait modifications and reaching. As such, the results are compatible with the hypothesis that the corticospinal circuits used to control reaching evolved from those used to precisely modify gait. SIGNIFICANCE STATEMENT In an article in 1989, Georgopoulos and Grillner (1989) proposed that the corticospinal control mechanisms used for reaching movements in primates may have evolved from those used to control precise modifications of gait during quadrupedal locomotion. In this article, we provide a test of this hypothesis by recording the activity of individual motor cortical cells during both behaviors. Our results are compatible with the hypothesis in that they demonstrate that individual cortical neurons exhibit similar qualitative and quantitative patterns during each behavior. Beyond a general similarity of activity patterns, we show that some cortical

  15. Efficacy of Admission Screening for Extended-Spectrum Beta-Lactamase Producing Enterobacteriaceae

    PubMed Central

    Lowe, Christopher F.; Katz, Kevin; McGeer, Allison J.; Muller, Matthew P.

    2013-01-01

    Objective We hypothesized that admission screening for extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) reduces the incidence of hospital-acquired ESBL-E clinical isolates. Design Retrospective cohort study. Setting 12 hospitals (6 screening and 6 non-screening) in Toronto, Canada. Patients All adult inpatients with an ESBL-E positive culture collected from 2005–2009. Methods Cases were defined as hospital-onset (HO) or community-onset (CO) if cultures were positive after or before 72 hours. Efficacy of screening in reducing HO-ESBL-E incidence was assessed with a negative binomial model adjusting for study year and CO-ESBL-E incidence. The accuracy of the HO-ESBL-E definition was assessed by re-classifying HO-ESBL-E cases as confirmed nosocomial (negative admission screen), probable nosocomial (no admission screen) or not nosocomial (positive admission screen) using data from the screening hospitals. Results There were 2,088 ESBL-E positive patients and incidence of ESBL-E rose from 0.11 to 0.42 per 1,000 inpatient days between 2005 and 2009. CO-ESBL-E incidence was similar at screening and non-screening hospitals but screening hospitals had a lower incidence of HO-ESBL-E in all years. In the negative binomial model, screening was associated with a 49.1% reduction in HO-ESBL-E (p<0.001). A similar reduction was seen in the incidence of HO-ESBL-E bacteremia. When HO-ESBL-E cases were re-classified based on their admission screen result, 46.5% were positive on admission, 32.5% were confirmed as nosocomial and 21.0% were probable nosocomial cases. Conclusions Admission screening for ESBL-E is associated with a reduced incidence of HO-ESBL-E. Controlled, prospective studies of admission screening for ESBL-E should be a priority. PMID:23638132

  16. The Probabilistic Admissible Region with Additional Constraints

    NASA Astrophysics Data System (ADS)

    Roscoe, C.; Hussein, I.; Wilkins, M.; Schumacher, P.

    The admissible region, in the space surveillance field, is defined as the set of physically acceptable orbits (e.g., orbits with negative energies) consistent with one or more observations of a space object. Given additional constraints on orbital semimajor axis, eccentricity, etc., the admissible region can be constrained, resulting in the constrained admissible region (CAR). Based on known statistics of the measurement process, one can replace hard constraints with a probabilistic representation of the admissible region. This results in the probabilistic admissible region (PAR), which can be used for orbit initiation in Bayesian tracking and prioritization of tracks in a multiple hypothesis tracking framework. The PAR concept was introduced by the authors at the 2014 AMOS conference. In that paper, a Monte Carlo approach was used to show how to construct the PAR in the range/range-rate space based on known statistics of the measurement, semimajor axis, and eccentricity. An expectation-maximization algorithm was proposed to convert the particle cloud into a Gaussian Mixture Model (GMM) representation of the PAR. This GMM can be used to initialize a Bayesian filter. The PAR was found to be significantly non-uniform, invalidating an assumption frequently made in CAR-based filtering approaches. Using the GMM or particle cloud representations of the PAR, orbits can be prioritized for propagation in a multiple hypothesis tracking (MHT) framework. In this paper, the authors focus on expanding the PAR methodology to allow additional constraints, such as a constraint on perigee altitude, to be modeled in the PAR. This requires re-expressing the joint probability density function for the attributable vector as well as the (constrained) orbital parameters and range and range-rate. The final PAR is derived by accounting for any interdependencies between the parameters. Noting that the concepts presented are general and can be applied to any measurement scenario, the idea

  17. Curved film cooling admission tube

    NASA Technical Reports Server (NTRS)

    Graham, R. W.; Papell, S. S. (Inventor)

    1980-01-01

    Effective film cooling to protect a wall surface from a hot fluid which impinges on or flows along the surface is provided. A film of cooling fluid having increased area is provided by changing the direction of a stream of cooling fluid through an angle of from 135 deg. to 165 deg. before injecting it through the wall into the hot flowing gas. The 1, cooling fluid is injected from an orifice through a wall into a hot flowing gas at an angle to form a cooling fluid film. Cooling fluid is supplied to the orifice from a cooling fluid source via a turbulence control passageway having a curved portion between two straight portions. The angle through which the direction of the cooling fluid is turned results in less mixing of the cooling fluid with the hot gas, thereby substantially increasing the length of the film in a downstream direction.

  18. Interpreters' Training: Learning to Control the Bilingual Switch Mechanism.

    ERIC Educational Resources Information Center

    Coughlin, Josette

    1985-01-01

    Looks at the latest scientific discoveries in polyglossia as they pertain to understanding the mechanisms which allow simultaneous interpretation to take place. Considers separately the input and output switch mechanisms. Discusses the importance of anticipatory strategies to facilitate language switching in simultaneous translation.

  19. Passive dynamic controllers for non-linear mechanical systems

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Wu, Shih-Chin; Phan, Minh; Longman, Richard W.

    1992-01-01

    The objective is to develop active model-independent controllers for slewing and vibration control of nonlinear multibody flexible systems, including flexible robots. The topics are presented in viewgraph form and include: passive stabilization; work-energy rate principle; Liapunov theory; displacement feedback; dynamic controller; displacement and acceleration feedback; velocity feedback; displacement feedback; physical interaction; a 6-DOF robot; and simulation results.

  20. Air pollution and emergency hospital admissions for cardiovascular diseases in Valencia, Spain

    PubMed Central

    Ballester, F; Tenias, J; Perez-Hoyos, S

    2001-01-01

    STUDY OBJECTIVE—To estimate the short-term association between air pollution levels and emergency hospital admissions for cardiovascular diseases in Valencia, within 1994-1996 period.
DESIGN—Daily levels of air pollution and emergency admissions for cardiovascular diseases were related to using an ecological time series design. The number of admissions was obtained from the hospital records database. Selected groups of causes were all cardiovascular diseases, heart admissions, and admissions for cerebrovascular diseases. The number of admissions for digestive diseases was used as control. Pollutants were black smoke, sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3). Magnitude of association was estimated by Poisson autoregresive regression. Estimations were calculated according the hottest (May to October) and the coldest (November to April) periods.
SETTING—City of Valencia, Spain, about 750 000 inhabitants.
PARTICIPANTS—People being admitted to the two major hospitals in the city, with a catchment area of nearly 400 000 inhabitants.
MAIN RESULTS—For the whole period, a significant association for SO2-24 h was found so a rise in its levels of 10 µg/m3 was associated with an increment of 3% (95%CI 0.4 to 5.7%) in the expected number of cardiovascular admissions. A significant association for black smoke, SO2-24 h, SO2-1 h, and CO-1 h was found in the hottest semester. All these associations were verified with a lag of two days. The estimates of the associations for particles, SO2, and CO were affected by the inclusion of the other pollutants in their models. NO2 was independently associated with cerebrovascular admissions. There were no significant associations between air pollution and admissions for digestive diseases.
CONCLUSIONS—Current levels of air pollution and emergency cardiovascular admissions are significantly related in Valencia.


Keywords: air pollution; cardiovascular disease

  1. Compound control strategy used in Electro-Mechanical Actuator (EMA)

    NASA Astrophysics Data System (ADS)

    Fu, Yongling; Yan, Meng

    2017-01-01

    This article briefly describes the overall structure of the loading test rig; establish mathematical model of loading EMA, analyze its stability, surplus force and other properties in MATLAB; propose a compound control strategy combined speed feedback, PID and feed-forward compensation based on structure invariance principle. To verify the effectiveness of the control strategy, do a co-simulation by designing a controller based on the control strategy above in MATLAB and building the EMA model in AMESim. The results show that the compound control strategy can significantly improve dynamic tracking accuracy and reduce surplus force.

  2. 46 CFR 160.170-15 - Production inspections, tests, quality control, and conformance of release mechanisms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., quality control, and conformance of release mechanisms. (a) Unless the Commandant directs otherwise, an...— (1) Institute a quality control procedure to ensure that all production release mechanisms are... 46 Shipping 6 2012-10-01 2012-10-01 false Production inspections, tests, quality control,...

  3. Association between antipsychotic/antidepressant drug treatments and hospital admissions in schizophrenia assessed using a mental health case register

    PubMed Central

    Cardinal, Rudolf N; Savulich, George; Mann, Louisa M; Fernández-Egea, Emilio

    2015-01-01

    Background: The impact of psychotropic drug choice upon admissions for schizophrenia is not well understood. Aims: To examine the association between antipsychotic/antidepressant use and time in hospital for patients with schizophrenia. Methods: We conducted an observational study, using 8 years’ admission records and electronically generated drug histories from an institution providing secondary mental health care in Cambridgeshire, UK, covering the period 2005–2012 inclusive. Patients with a coded ICD-10 diagnosis of schizophrenia were selected. The primary outcome measure was the time spent as an inpatient in a psychiatric unit. Antipsychotic and antidepressant drugs used by at least 5% of patients overall were examined for associations with admissions. Periods before and after drug commencement were compared for patients having pre-drug admissions, in mirror-image analyses correcting for overall admission rates. Drug use in one 6-month calendar period was used to predict admissions in the next period, across all patients, in a regression analysis accounting for the effects of all other drugs studied and for time. Results: In mirror-image analyses, sulpiride, aripiprazole, clozapine, and olanzapine were associated with fewer subsequent admission days. In regression analyses, sulpiride, mirtazapine, venlafaxine, and clozapine–aripiprazole and clozapine–amisulpride combinations were associated with fewer subsequent admission days. Conclusions: Use of these drugs was associated with fewer days in hospital. Causation is not implied and these findings require confirmation by randomized controlled trials. PMID:27336041

  4. Guideposts of an Effective Admissions Program for the Private School.

    ERIC Educational Resources Information Center

    Johnson, Raymond E.

    1980-01-01

    Describes fundamental guideposts for an effective private school admissions program. Included are a clear statement of purpose, informative literature, clearly stated admission requirements, standardized testing, a cooperative faculty, image positioning and a recruiting plan. (RC)

  5. Mechanical Control of the Sense of Touch by β Spectrin

    PubMed Central

    Krieg, Michael; Dunn, Alexander R.; Goodman, Miriam B.

    2014-01-01

    The ability to sense and respond to mechanical stimuli emanates from sensory neurons and is shared by most, if not all animals. Exactly how such neurons receive and distribute mechanical signals during touch sensation remains mysterious. Here, we show that sensation of mechanical forces depends on a continuous, pre-stressed spectrin cytoskeleton inside neurons. Mutations in the tetramerization domain of C. elegans β-spectrin (UNC-70), an actin-membrane cross-linker, cause defects in sensory neuron morphology under compressive stress in moving animals. Through AFM force spectroscopy experiments on isolated neurons, in vivo laser axotomy and FRET imaging to measure force across single cells and molecules, we show that spectrin is held under constitutive tension in living animals, which contributes to an elevated pre-stress in touch receptor neurons. Genetic manipulations that decrease such spectrin-dependent tension also selectively impair touch sensation, suggesting that such pretension is essential for efficient responses to external mechanical stimuli. PMID:24561618

  6. Coarse Particulate Air Pollution Associated with Increased Risk of Hospital Admissions for Respiratory Diseases in a Tropical City, Kaohsiung, Taiwan

    PubMed Central

    Cheng, Meng-Hsuan; Chiu, Hui-Fen; Yang, Chun-Yuh

    2015-01-01

    This study was undertaken to determine whether there was an association between coarse particles (PM2.5–10) levels and frequency of hospital admissions for respiratory diseases (RD) in Kaohsiung, Taiwan. Hospital admissions for RD including chronic obstructive pulmonary disease (COPD), asthma, and pneumonia, and ambient air pollution data levels for Kaohsiung were obtained for the period from 2006 to 2010. The relative risk of hospital admissions for RD was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model (without adjustment for other pollutants), increased rate of admissions for RD were significantly associated with higher coarse PM levels only on cool days (<25 °C), with a 10 µg/m3 elevation in PM2.5–10 concentrations associated with a 3% (95% CI = 1%–5%) rise in COPD admissions, 4% (95% CI = 1%–7%) increase in asthma admissions, and 3% (95% CI = 2%–4%) rise in pneumonia admissions. No significant associations were found between coarse particle levels and the number of hospital admissions for RD on warm days. In the two-pollutant models, PM2.5–10 levels remained significantly correlated with higher rate of RD admissions even controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, or ozone on cool days. This study provides evidence that higher levels of PM2.5–10 enhance the risk of hospital admissions for RD on cool days. PMID:26501308

  7. Independent backup mode transfer and mechanism for digital control computers

    NASA Technical Reports Server (NTRS)

    Tulpule, Bhalchandra R. (Inventor); Oscarson, Edward M. (Inventor)

    1992-01-01

    An interrupt is provided to a signal processor having a non-maskable interrupt input, in response to the detection of a request for transfer to backup software. The signal processor provides a transfer signal to a transfer mechanism only after completion of the present machine cycle. Transfer to the backup software is initiated by the transfer mechanism only upon reception of the transfer signal.

  8. The Parent Control in the Mechanical Engineering Management-Holding

    NASA Astrophysics Data System (ADS)

    Šnircová, Jana; Hodulíková, Petra; Joehnk, Peter

    2012-12-01

    The group of entities under the control of parent, so called holding, is arisen as the result and the most often used form of the business concentration nowadays. The paper is focused to find special tasks of parent company for to preserve effective unified economic control in the management-holding. The unified economic control the holding exists in the conditions of the main conflict of interest - holding is not a legal but economic unit and the connected companies into it have a legal autonomy with the economic dependence. The unified economic control limits the financial independence of every individual company of the holding. The attention in the paper is concentrated to the management concept of the parent control, i.e. the parent company supervises the control of intragroup flows and all of subsidiaries production activities.

  9. SPRING DRIVEN ACTUATING MECHANISM FOR NUCLEAR REACTOR CONTROL

    DOEpatents

    Bevilacqua, F.; Uecker, D.F.; Groh, E.F.

    1962-01-23

    l962. rod in a nuclear reactor to shut it down. The control rod or an extension thereof is wound on a drum as it is withdrawn from the reactor. When an emergency occurs requiring the reactor to be shut down, the drum is released so as to be free to rotate, and the tendency of the control rod or its extension coiled on the drum to straighten itself is used for quickly returning the control rod to the reactor. (AEC)

  10. New insights into the mechanisms of itch: are pain and itch controlled by distinct mechanisms?

    PubMed Central

    Liu, Tong; Ji, Ru-Rong

    2013-01-01

    Itch and pain are closely related but distinct sensations. They share largely overlapping mediators and receptors, and itch-responding neurons are also sensitive to pain stimuli. Itch-mediating primary sensory neurons are equipped with distinct receptors and ion channels for itch transduction, including Mas-related G protein-coupled receptors (Mrgprs), protease-activated receptors (PARs), histamine receptors, bile acid receptor (TGR5), toll-like receptors (TLRs), and transient receptor potential subfamily V1/A1 (TRPV1/A1). Recent progress has indicated the existence of an itch-specific neuronal circuitry. The MrgprA3-expressing primary sensory neurons exclusively innervate the epidermis of skin and their central axons connect with gastrin-releasing peptide receptor (GRPR)-expressing neurons in the superficial spinal cord. Notably, ablation of MrgprA3-expressing primary sensory neurons or GRPR-expressing spinal cord neurons results in selective reduction in itch but not pain. Chronic itch results from dysfunction of the immune and nervous system and can manifest as neural plasticity, despite the fact that chronic itch is often treated by dermatologists. While differences between acute pain and acute itch are striking, chronic itch and chronic pain share many similar mechanisms, including peripheral sensitization (increased responses of primary sensory neurons to itch and pain mediators), central sensitization (hyperactivity of spinal projection neurons and excitatory interneurons), loss of inhibitory control in the spinal cord, and neuro-immune and neuro-glial interactions. Notably, painful stimuli can elicit itch in some chronic conditions (e.g., atopic dermatitis) and some drugs for treating chronic pain are also effective in chronic itch. Thus, itch and pain have more similarities in pathological and chronic conditions. PMID:23636773

  11. Mechanisms of Molecular Response in the Optimal Control of Photoisomerization

    SciTech Connect

    Dietzek, Benjamin; Brueggemann, Ben; Pascher, Torbjoern; Yartsev, Arkady

    2006-12-22

    We report on adaptive feedback control of photoinduced barrierless isomerization of 1,1'-diethyl-2,2'-cyanine in solution. We compare the effect of different fitness parameters and show that optimal control of the absolute yield of isomerization (photoisomer concentration versus excitation photons) can be achieved, while the relative isomerization yield (photoisomer concentration versus number of relaxed excited-state molecules) is unaffected by adaptive feedback control. The temporal structure of the optimized excitation pulses allows one to draw clear mechanistic conclusions showing the critical importance of coherent nuclear motion for the control of isomerization.

  12. 42 CFR 456.171 - Medicaid agency review of need for admission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Medicaid agency review of need for admission. 456.171 Section 456.171 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS UTILIZATION CONTROL Utilization Control:...

  13. CONTROL ROD DRIVE MECHANISM FOR A NUCLEAR REACTOR

    DOEpatents

    Hawke, B.C.; Liederbach, F.J.; Lones, W.

    1963-05-14

    A lead-screw-type control rod drive featuring an electric motor and a fluid motor arranged to provide a selectably alternative driving means is described. The electric motor serves to drive the control rod slowly during normal operation, while the fluid motor, assisted by an automatic declutching of the electric motor, affords high-speed rod insertion during a scram. (AEC)

  14. Passive dynamic controllers for non-linear mechanical systems

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Wu, Shih-Chin; Phan, Minh; Longman, Richard W.

    1991-01-01

    A methodology for model-independent controller design for controlling large angular motion of multi-body dynamic systems is outlined.The controlled system may consist of rigid and flexible components that undergo large rigid body motion and small elastic deformations. Control forces/torques are applied to drive the system, and at the same time suppress the vibrations due to flexibility of the components. The proposed controller consists of passive second-order systems which may be designed with little knowledge of the system parameters, even if the controlled system is non-linear. Under rather general assumptions, the passive design assures that the closed loop system has guaranteed stability properties. Unlike positive real controller design, stabilization can be accomplished without direct velocity feedback. In addition, the second-order passive design allows dynamic feedback controllers with considerable freedom to tune for desired system response, and to avoid actuator saturation. After developing the basic mathematical formulation of the design methodology, simulation results are presented to illustrate the proposed approach applied to a flexible six-degree-of-freedom manipulator.

  15. High frequency drive mechanism for an active controls systems aircraft control surface

    NASA Technical Reports Server (NTRS)

    Smith, H. E.

    1981-01-01

    The mechanism was successfully utilized on a wind tunnel model tested in the transonic blow down tunnel. The mechanism is also applicable to a flying aircraft. Several interrelated mechanical subsystems were utilized, including a low inertia antibacklash drive mechanism for high frequency oscillation and a compact antibacklash drive mechanism for conversion of rotary motion to linear motion.

  16. Reclaiming the Educational Role of Chief Admission Officers.

    ERIC Educational Resources Information Center

    McDonough, Patricia; Robertson, Larry

    1995-01-01

    Describes changes that have occurred in high schools, colleges, and the entrepreneurial admission sector. Relates the evolution of the admission officer's job since the early 1960s and the profession's rapid growth. Details the hybrid role of marketer and educator for chief admissions officers, and issues a call for professional standards. (RJM)

  17. Female and Male Admission to Graduate School: An Illustrative Inquiry

    ERIC Educational Resources Information Center

    Maxwell, Scott E.; Jones, Lyle V.

    1976-01-01

    Female and male admission rates to four graduate programs at a university were compared over a two year time period to assess possible sex bias in admission procedures. The overall results showed that sex played only a modest role in admission decisions. (Author/DEP)

  18. Behind the Scenes, Admissions Offices Conquer Mounds of Mail

    ERIC Educational Resources Information Center

    Farrell, Elizabeth F.

    2008-01-01

    If coming back to work after winter break seems daunting, consider the plight of college-admissions officials. While most high-school students are breathing a sigh of relief after finally submitting their applications, those on the receiving end are rolling up their sleeves. January is crunch time for many admissions offices. Admissions officers…

  19. 45 CFR 618.305 - Preference in admission.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Preference in admission. 618.305 Section 618.305 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.305 Preference in admission....

  20. 45 CFR 618.305 - Preference in admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Preference in admission. 618.305 Section 618.305 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.305 Preference in admission....

  1. 45 CFR 618.305 - Preference in admission.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Preference in admission. 618.305 Section 618.305 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.305 Preference in admission....

  2. 45 CFR 618.305 - Preference in admission.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Preference in admission. 618.305 Section 618.305 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION... Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 618.305 Preference in admission....

  3. The Roles of Testing and Diversity in College Admissions.

    ERIC Educational Resources Information Center

    Clarke, Marguerite; Shore, Arnold

    In order to understand the roles of test scores and diversity characteristics (including race and ethnicity) in the admission process, National Board researchers interviewed admissions directors who worked at selective public and private institutions are well as admissions consultants in the summer and fall of 1999. This report presents an…

  4. Equity of Access. New Approaches to Minority Admissions

    ERIC Educational Resources Information Center

    Bingham, Rebecca Saady

    1978-01-01

    One new approach to the admission of minorities to medical schools is that of the Simulated Minority Admission Exercises (SMAE). It sensitizes admission committee members to the different backgrounds of minority applicants and teaches them to evaluate them more effectively. (Author/AM)

  5. 49 CFR 511.34 - Requests for admission.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for the admission, for the purposes of the pending proceeding only, of the truth of any matters within... served upon any party after filing of the answer. Each matter as to which an admission is requested shall be separately set forth. (b) Procedure for response. The matter as to which an admission is...

  6. 6 CFR 17.305 - Preference in admission.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Preference in admission. 17.305 Section 17.305... OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 17.305 Preference in admission. A...

  7. 18 CFR 1317.305 - Preference in admission.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Preference in admission... NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Admission and Recruitment Prohibited § 1317.305 Preference in admission....

  8. 49 CFR 1114.3 - Admissibility of business records.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 8 2013-10-01 2013-10-01 false Admissibility of business records. 1114.3 Section... § 1114.3 Admissibility of business records. Any writing or record, whether in the form of an entry in a... be admissible as evidence thereof if it appears that it was made in the regular course of...

  9. 49 CFR 1114.3 - Admissibility of business records.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Admissibility of business records. 1114.3 Section... § 1114.3 Admissibility of business records. Any writing or record, whether in the form of an entry in a... be admissible as evidence thereof if it appears that it was made in the regular course of...

  10. 49 CFR 1114.3 - Admissibility of business records.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Admissibility of business records. 1114.3 Section... § 1114.3 Admissibility of business records. Any writing or record, whether in the form of an entry in a... be admissible as evidence thereof if it appears that it was made in the regular course of...

  11. 42 CFR 456.122 - Evaluation criteria for admission review.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Evaluation criteria for admission review. 456.122...: Review of Need for Admission 1 § 456.122 Evaluation criteria for admission review. The UR plan must provide that— (a) The committee develops written medical care criteria to assess the need for...

  12. Eliminating Standardized Tests in College Admissions: The New Affirmative Action?

    ERIC Educational Resources Information Center

    Zwick, Rebecca

    1999-01-01

    Eliminating the Scholastic Aptitude Test for college admissions might seem a form of covert affirmative action. Although it is possible to design a workable admissions policy that excludes standardized tests (as 15 percent of colleges have done), banishing admissions tests to further a social-policy goal indirectly is unsound policy. (Contains 25…

  13. Molecular control of myocardial mechanics and energetics: the chemo-mechanical conversion.

    PubMed

    Landesberg, A

    1997-01-01

    Energy consumption in the cardiac muscle is characterized by two basic phenomena: 1) The well known linear relationship between energy consumption by the sarcomere and the mechanical energy it generates, and 2) the ability to modulate the generated mechanical energy and energy consumption to the various loading conditions, as is manifested by the Frank-Starling Law and the Fenn effect. These basic phenomena are analyzed here based on coupling calcium kinetics with crossbridge (Xb) cycling. Our previous studies established the existence of two feedback mechanism: 1) a positive feedback mechanism, the cooperativity, whereby the affinity of the troponin for calcium, and hence Xb and actomyosin-ATPase recruitment, depends on the number of force generating Xbs, and 2) a mechanical feedback, whereby the filaments shortening velocity, or the Xb strain rate, determines the rate of Xb turnover from the strong to the weak conformation. The cooperativity mechanism determines the force-length relationship (FLR) and the related Frank-Starling Law. It also provides the basis for the regulation of energy consumption and the ability of the muscle to adapt its energy consumption to the loading conditions. The mechanical feedback regulates the shortening velocity and provides the analytical solution for the experimentally derived Hill's equation for the force-velocity relationship (FVR). The mechanical feedback regulates the generated power and provides the linear relationship between energy consumption and the generated mechanical energy, i.e., the external work done and the liberated heat. Thus, the two feedback mechanisms that regulate sarcomere dynamics, and determine the FLR and FVR, also regulate the energy consumption and the mechanical energy generated by the muscle.

  14. Assisted living nursing practice: admission assessment.

    PubMed

    Mitty, Ethel; Flores, Sandi

    2007-01-01

    Admission assessment, generally conducted by a registered nurse, is autonomous, without opportunity for dialogue with colleagues and other health care professionals and bounded by the nurse's knowledge and skills, state regulations, facility practices, and marketing. The fact that some states permit admission and retention of nursing home level-of-care residents and provision of end-of-life care means that the assessment has to be able to predict the resident's likely trajectory of well-being as well as chronic illness exacerbation. The nurse must have a clear perspective on staff competencies and judge whether additional education or training will be necessary. This article reviews assessment standards of practice as put forth by the American Assisted Living Nurses Association as part of its application for recognition of assisted living nursing as specialty nursing practice by the American Nurses Association. The role of the Licensed Practical Nurse/Licensed Vocational Nurse in resident assessment is also discussed.

  15. Oestrogen Modulates Hypothalamic Control of Energy Homeostasis Through Multiple Mechanisms

    PubMed Central

    Roepke, Troy A.

    2009-01-01

    The control of energy homeostasis in women is correlated with the anorectic effects of oestrogen, which can attenuate body weight gain and reduce food intake in rodent models. This review will investigate the multiple signalling pathways and cellular targets that oestrogen utilises to control energy homeostasis in the hypothalamus. Oestrogen affects all of the hypothalamic nuclei that control energy homeostasis. Oestrogen controls the activity of hypothalamic neurones through gene regulation and neuronal excitability. Oestrogen’s primary cellular pathway is the control of gene transcription through the classical ERs (ERα and ERβ) with ERα having the primary role in energy homeostasis. Oestrogen also controls energy homeostasis through membrane-mediated events via membrane-associated ERs or a novel, putative membrane ER that is coupled to G-proteins. Therefore, oestrogen has at least two receptors with multiple signalling and transcriptional pathways to activate during immediate and long-term anorectic effects. Ultimately, it is the interactions of all the receptor-mediated processes in hypothalamus and other areas of the CNS that will determine the anorectic effects of oestrogen and its control of energy homeostasis. PMID:19076267

  16. Lasers, the Price of Admission in 2045

    DTIC Science & Technology

    2015-04-01

    altitude. Water vapor, pollutants , and other particles in the air , which are more prevalent at lower altitudes, cause absorption and scattering. These...AU/ACSC/DAYTON, J/AY15 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY LASERS, THE PRICE OF ADMISSION IN 2045 by John G. Dayton, Maj, USAF...the Degree of MASTER OF OPERATIONAL ARTS AND SCIENCE Advisors: Lt Col Paul P. Clemans, Maj Thomas E. Kiesling Maxwell Air Force Base, Alabama

  17. Lyapunov based nonlinear control of electrical and mechanical systems

    NASA Astrophysics Data System (ADS)

    Behal, Aman

    This Ph.D. dissertation describes the design and implementation of various control strategies centered around the following applications: (i) an improved indirect field oriented controller for the induction motor, (ii) partial state feedback control of an induction motor with saturation effects, (iii) tracking control of an underactuated surface vessel, and (iv) an attitude tracking controller for an underactuated spacecraft. The theory found in each of these sections is demonstrated through simulation or experimental results. An introduction to each of these four primary chapters can be found in chapter one. In the second chapter, the previously published tracking control of [16] 1 is presented in the indirect field oriented control (IFOC) notation to achieve exponential rotor velocity/rotor flux tracking. Specifically, it is illustrated how the proposed IFOC controller can be rewritten in the manner of [16] to allow for a direct Lyapunov stability proof. Experimental results (implemented with the IFOC algorithm) are provided to corroborate the efficacy of the algorithm. In the third chapter, a singularity-free, rotor position tracking controller is presented for the full order, nonlinear dynamic model of the induction motor that includes the effects of magnetic saturation. Specifically, by utilizing the pi-equivalent saturation model, an observer/controller strategy is designed that achieves semi-global exponential rotor position tracking and only requires stator current, rotor velocity, and rotor position measurements. Simulation and experimental results are included to demonstrate the efficacy of the proposed algorithm. In the fourth chapter, a continuous, time-varying tracking controller is designed that globally exponentially forces the position/orientation tracking error of an under-actuated surface vessel to a neighborhood about zero that can be made arbitrarily small (i.e., global uniformly ultimately boundedness (GUUB)). The result is facilitated by

  18. The Application of LOGO! in Control System of a Transmission and Sorting Mechanism

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Lv, Yuan-Jun

    Logic programming of general logic control module LOGO! has been recommended the application in transmission and sorting mechanism. First, the structure and operating principle of the mechanism had been introduced. Then the pneumatic loop of the mechanism had been plotted in the software of FluidSIM-P. At last, pneumatic loop and motors had been control by LOGO!, which makes the control process simple and clear instead of the complicated control of ordinary relay. LOGO! can achieve the complicated interlock control composed of inter relays and time relays. In the control process, the logic control function of LOGO! is fully used to logic programming so that the system realizes the control of air cylinder and motor. It is reliable and adjustable mechanism after application.

  19. Multiplicity of mechanisms govern efficacy of anaerobic soil disinfestation for soil-borne disease control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies demonstrated that carbon input type influenced control of various fungi, oomycetes and plant parasitic nematodes with anaerobic soil disinfestation (ASD). Findings implicated multiple mechanisms may contribute to the overall level of disease control attained. In strawberry field trials, ASD ...

  20. 46 CFR 160.133-15 - Production inspections, tests, quality control, and conformance of release mechanisms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 6 2013-10-01 2013-10-01 false Production inspections, tests, quality control, and... SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL LIFESAVING..., tests, quality control, and conformance of release mechanisms. (a) Unless the Commandant...

  1. Characteristics of delayed admission to stroke unit.

    PubMed

    Silvestrelli, Giorgio; Parnetti, Lucilla; Tambasco, Nicola; Corea, Francesco; Capocchi, Giuseppe

    2006-01-01

    Early admission to stroke unit (SU) and factors that may cause admission delay represent relevant issues to obtain an optimal management of acute stroke. This study was aimed at recording timing from clinical onset to admission to our SU and to identify the reasons for delay. We prospectively examined acute stroke patients consecutively admitted to the Perugia SU. Baseline characteristics of stroke patients, stroke type and etiology, time from symptom onset to arrival in the SU were obtained from the Hospital-Based Perugia Stroke Registry. 60.8% of 2,213 consecutive stroke patients admitted to the SU arrived within 6 hrs and 39.2% after 6 hrs. Underestimation of symptoms was the cause of delay in 48.7% of cases. Younger age, especially for females, ischemic stroke, mild and/or unspecific symptoms and the underestimation of symptoms seem to be the main reasons for delayed arrival in the SU. To increase the proportion of stroke patients arriving in the SU within 3 hr of symptom onset, it is necessary to improve public and general practitioner awareness of stroke through educational programs.

  2. Basal Ganglia Mechanisms Underlying Precision Grip Force Control

    PubMed Central

    Prodoehl, Janey; Corcos, Daniel M.; Vaillancourt, David E.

    2009-01-01

    The classic grasping network has been well studied but thus far the focus has been on cortical regions in the control of grasping. Sub-cortically, specific nuclei of the basal ganglia have been shown to be important in different aspects of precision grip force control but these findings have not been well integrated. In this review we outline the evidence to support the hypothesis that key basal ganglia nuclei are involved in parameterizing specific properties of precision grip force. We review literature from different areas of human and animal work that converges to build a case for basal ganglia involvement in the control of precision gripping. Following on from literature showing anatomical connectivity between the basal ganglia nuclei and key nodes in the cortical grasping network, we suggest a conceptual framework for how the basal ganglia could function within the grasping network, particularly as it relates to the control of precision grip force. PMID:19428499

  3. Group Theoretical Approach for Controlled Quantum Mechanical Systems

    DTIC Science & Technology

    2007-11-06

    evolution equation with Hamiltonians which may possess discrete , continuous, and mixed spectrum. For such a quantum system, the Hamiltonian operator...study of classical linear and nonlinear systems, which proves to be very useful in understanding the design problems such as disturbance decoupling...developed by Kunita can then be implemented to establish controllability conditions for the original time-dependent Schrodinger control problem. The end

  4. Control of Vibration in Mechanical Systems Using Shaped Reference Inputs

    DTIC Science & Technology

    1988-01-01

    SCARA .- robot arm. Sehitoglu and Aristizabal [151 used a cycloidal motion profile to generate smooth motions . However, no attempt was made to tune these...of a Trajectory Controller for Industrial Robots Using Bang-Bang and Cycloidal Motion Profiles," Robotics : Theory and Applications, ASME Winter Annual...Control on Trajectory Tracking N." Errors," Proceedings of the 1986 IEEE International Conference on Robotics 0 and Automation. San Francisco, CA

  5. Diagnosis and control of 3D elastic mechanical structures

    NASA Astrophysics Data System (ADS)

    Krajcin, Idriz; Soeffker, Dirk

    2005-05-01

    In this paper, a model-based approach for fault detection and vibration control of flexible structures is proposed and applied to 3D-structures. Faults like cracks or impacts acting on a flexible structure are considered as unknown inputs acting on the structure. The Proportional-Integral-Observer (PI-Observer) is used to estimate the system states as well as unknown inputs acting on a system. Also the effects of structural changes are understood as external effects (related to the unchanged structure) and are considered as fictitious external forces or moments. The paper deals with the design of the PI-Observer for practical applications when measurement noise and model uncertainties are present and shows its performance in experimental results. As examples, impacts acting upon a one side clamped elastic beam and on a thin plate structure are estimated using displacement or strain measurements. To control the vibration of the flexible plate, two piezoelectric patches bonded on the structure are used as actuators. The control algorithm introduced in this contribution contains a state feedback control and additionally a disturbance rejection. The disturbances are estimated using the PI-Observer. Experimental results show the performance and the robustness properties of the control strategy for the vibration control of a very thin plate.

  6. Complexity in College Admission: Fact or Urban Myth. Research Findings of Parent and Student Perceptions of Complexity in College Admission

    ERIC Educational Resources Information Center

    College Board Advocacy & Policy Center, 2010

    2010-01-01

    In September 2007, the College Board formed the Task Force on Admissions in the 21st Century in response to a request from the Guidance and Admission Assembly Council (GAA Council) to more closely examine the high-school-to-college transition process. Each spring, at the conclusion of the college admission cycle, there is much discussion in the…

  7. A Role for Marketing in College Admissions. Papers Presented at the Colloquium on College Admissions, May 16-l8, 1976.

    ERIC Educational Resources Information Center

    College Entrance Examination Board, New York, NY.

    This collection stresses the need for informed and more sophisticated marketing techniques for college admissions officers to help them cope with the decreasing number of prospective college students. The importance of the college admissions office is increasing as admissions becomes a more crucial element to the colleges' financial well-being.…

  8. Effects of the Economy on the Admission Process: 2008-09. National Association for College Admission Counseling, September 2009

    ERIC Educational Resources Information Center

    National Association for College Admission Counseling, 2009

    2009-01-01

    The 2008-09 college admission cycle took place during a period of heightened economic uncertainty. When added to the annual uncertainty of the admission process--for both students seeking college admission offers and colleges seeking to predict their annual enrollment yield--the economic environment caused great concern among colleges and students…

  9. Admission Requirements for Transfer and Non-Transfer Students: Should One Size Fit All?

    ERIC Educational Resources Information Center

    Pharr, Steven; Lawrence, John J.

    2007-01-01

    Purpose: To examine the efficacy of admission requirements as predictors of academic success in core business coursework, and as a rationing mechanism for limited course capacity, for both transfer and non-transfer students following integration of the core business curriculum. Design/methodology/approach: Regression analysis is used to test the…

  10. Biomolecular Mechanisms Controlling Metal and Radionuclide Transformations in Anaeromyxobacter dehalogenans

    SciTech Connect

    Beliaev, Alexander S.; Fredrickson, James K.; Loeffler, Frank E.; Sanford, Robert A.

    2006-06-01

    Microbiological reduction and immobilization of U(VI) and Tc(VII) has been proposed as a strategy for remediating radionuclide-contaminated environments. Numerous studies focusing on the reduction kinetics and speciation of these metals have been carried out using contaminated sediment samples, microbial consortia, and pure bacterial cultures. While previous work with model organisms has increased the general understanding of radionuclide transformation processes, fundamental questions regarding radionuclide reduction mechanisms by indigenous microorganisms are poorly understood, especially under the commonly encountered scenario where multiple electron acceptors are present. Therefore, the overall goal of the proposed research is to elucidate the molecular mechanisms of radionuclide biotransformation by Anaeromyxobacter dehalogenans, a predominant member of indigenous microorganism commonly found in contaminated subsurface environments, and to assess the effects of relevant environmental factors affecting these transformation reactions.

  11. Mechanical Control of Cell flow in Multicellular Spheroids

    NASA Astrophysics Data System (ADS)

    Delarue, Morgan; Montel, Fabien; Caen, Ouriel; Elgeti, Jens; Siaugue, Jean-Michel; Vignjevic, Danijela; Prost, Jacques; Joanny, Jean-François; Cappello, Giovanni

    2013-03-01

    Collective cell motion is observed in a wide range of biological processes. In tumors, physiological gradients of nutrients, growth factors, or even oxygen give rise to gradients of proliferation. We show using fluorescently labeled particles that these gradients drive a velocity field resulting in a cellular flow in multicellular spheroids. Under mechanical stress, the cellular flow is drastically reduced. We describe the results with a hydrodynamic model that considers only convection of the particles by the cellular flow.

  12. Aircraft Enroute Command and Control Comms Redesign Mechanical Documentation

    DTIC Science & Technology

    2015-12-01

    distribution unlimited. iii Contents List of Tables iv 1. Introduction 1 2. Mechanical Requirements 1 3. Drawing Package 2 4. Conclusion 3...Appendix. NG-JC2S Comms System Drawings 5 Distribution List 55 Approved for public release; distribution unlimited. iv List of Tables Table...1 NG-JC2S COMMS System drawing package .......................................2 Approved for public release; distribution unlimited. 1 1

  13. Probable Mechanisms of Needling Therapies for Myofascial Pain Control

    PubMed Central

    Chou, Li-Wei; Kao, Mu-Jung; Lin, Jaung-Geng

    2012-01-01

    Myofascial pain syndrome (MPS) has been defined as a regional pain syndrome characterized by muscle pain caused by myofascial trigger points (MTrPs) clinically. MTrP is defined as the hyperirritable spot in a palpable taut band of skeletal muscle fibers. Appropriate treatment to MTrPs can effectively relieve the clinical pain of MPS. Needling therapies, such as MTrP injection, dry needling, or acupuncture (AcP) can effectively eliminate pain immediately. AcP is probably the first reported technique in treating MPS patients with dry needling based on the Traditional Chinese Medicine (TCM) theory. The possible mechanism of AcP analgesia were studied and published in recent decades. The analgesic effect of AcP is hypothesized to be related to immune, hormonal, and nervous systems. Compared to slow-acting hormonal system, nervous system acts in a faster manner. Given these complexities, AcP analgesia cannot be explained by any single mechanism. There are several principles for selection of acupoints based on the TCM principles: “Ah-Shi” point, proximal or remote acupoints on the meridian, and extra-meridian acupoints. Correlations between acupoints and MTrPs are discussed. Some clinical and animal studies of remote AcP for MTrPs and the possible mechanisms of remote effectiveness are reviewed and discussed. PMID:23346211

  14. Mechanically Controlled Electron Transfer in a Single-Polypeptide Transistor

    NASA Astrophysics Data System (ADS)

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2017-01-01

    Proteins are of interest in nano-bio electronic devices due to their versatile structures, exquisite functionality and specificity. However, quantum transport measurements produce conflicting results due to technical limitations whereby it is difficult to precisely determine molecular orientation, the nature of the moieties, the presence of the surroundings and the temperature; in such circumstances a better understanding of the protein electron transfer (ET) pathway and the mechanism remains a considerable challenge. Here, we report an approach to mechanically drive polypeptide flip-flop motion to achieve a logic gate with ON and OFF states during protein ET. We have calculated the transmission spectra of the peptide-based molecular junctions and observed the hallmarks of electrical current and conductance. The results indicate that peptide ET follows an NC asymmetric process and depends on the amino acid chirality and α-helical handedness. Electron transmission decreases as the number of water molecules increases, and the ET efficiency and its pathway depend on the type of water-bridged H-bonds. Our results provide a rational mechanism for peptide ET and new perspectives on polypeptides as potential candidates in logic nano devices.

  15. Mechanically Controlled Electron Transfer in a Single-Polypeptide Transistor

    PubMed Central

    Sheu, Sheh-Yi; Yang, Dah-Yen

    2017-01-01

    Proteins are of interest in nano-bio electronic devices due to their versatile structures, exquisite functionality and specificity. However, quantum transport measurements produce conflicting results due to technical limitations whereby it is difficult to precisely determine molecular orientation, the nature of the moieties, the presence of the surroundings and the temperature; in such circumstances a better understanding of the protein electron transfer (ET) pathway and the mechanism remains a considerable challenge. Here, we report an approach to mechanically drive polypeptide flip-flop motion to achieve a logic gate with ON and OFF states during protein ET. We have calculated the transmission spectra of the peptide-based molecular junctions and observed the hallmarks of electrical current and conductance. The results indicate that peptide ET follows an NC asymmetric process and depends on the amino acid chirality and α-helical handedness. Electron transmission decreases as the number of water molecules increases, and the ET efficiency and its pathway depend on the type of water-bridged H-bonds. Our results provide a rational mechanism for peptide ET and new perspectives on polypeptides as potential candidates in logic nano devices. PMID:28051140

  16. [The neural mechanisms of cigarette craving and self-control].

    PubMed

    Hayashi, Takuya

    2014-01-01

    A craving for cigarettes or drugs has been believed to be a fundamental psychopathological factor that drives drug-seeking behavior and relapse. Behavioral economics has revealed context-dependent changes in drug craving. Neuroimaging studies have also found craving-related signals that were altered depending on the context of the experiments. A rational decision-making theory modeled such context-dependency and uncovered a pivotal role of the prefrontal cortical circuit in both self-control and craving. Future studies should address how dopaminergic function and stress circuits can modify the function of decision-making circuits, and produce either craving or self-control.

  17. Of special humanitarian concern: U.S. refugee admissions since passage of the Refugee Act.

    PubMed

    Gallagher, D; Forbes, S; Fagan, P W

    1986-01-01

    The Refugee Act of 1980 is the 1st comprehensive legislation on the admission of refugees to the US; in the 5+ years since its enactment, over 500,000 refugees from more than 25 countries have been admitted to the US. This report assesses the effectiveness of the law in achieving its objectives in making and implementing decisions about the admission of refugees. The objectives of the Act include 1) a desire for a humanitarian response to refugee emergencies and a desire for control over that response, 2) a concern that ideological and geographic restrictions on refugee admissions be removed, and 3) a desire to balance international concerns and domestic impacts in making decisions on refugee admissions. The authors conclude that the refugee program does not serve the broad humanitarian purposes of previous parole programs, due to its stringent review requirements. The formal Congressional Consultations on refugee numbers should be rescheduled to allow regular Congressional input. The program needs a contingency budget for changing situations. The program needs more input from nongovernmental agencies and information sources. Recommendations on refugee admission numbers and allocations have not been well substantiated. Determinations as to which refugees are of "special humanitarian concern" are made solely on the basis of nationality; these decisions should also incorporate other factors. Admissions priorities are generally based on ties to this country, but this makes the refugee program a surrogate immigration program. Although the application of the refugee definition is difficult in practice, it forms the essence of the admission process. US staff must be trained to make these decisions; indecisiveness must not be allowed to jeopardize refugees.

  18. Acute and Chronic Effects of Particles on Hospital Admissions in New-England

    PubMed Central

    Kloog, Itai; Coull, Brent A.; Zanobetti, Antonella; Koutrakis, Petros; Schwartz, Joel D.

    2012-01-01

    Background Many studies have reported significant associations between exposure to PM2.5 and hospital admissions, but all have focused on the effects of short-term exposure. In addition all these studies have relied on a limited number of PM2.5 monitors in their study regions, which introduces exposure error, and excludes rural and suburban populations from locations in which monitors are not available, reducing generalizability and potentially creating selection bias. Methods Using our novel prediction models for exposure combining land use regression with physical measurements (satellite aerosol optical depth) we investigated both the long and short term effects of PM2.5 exposures on hospital admissions across New-England for all residents aged 65 and older. We performed separate Poisson regression analysis for each admission type: all respiratory, cardiovascular disease (CVD), stroke and diabetes. Daily admission counts in each zip code were regressed against long and short-term PM2.5 exposure, temperature, socio-economic data and a spline of time to control for seasonal trends in baseline risk. Results We observed associations between both short-term and long-term exposure to PM2.5 and hospitalization for all of the outcomes examined. In example, for respiratory diseases, for every10-µg/m3 increase in short-term PM2.5 exposure there is a 0.70 percent increase in admissions (CI = 0.35 to 0.52) while concurrently for every10-µg/m3 increase in long-term PM2.5 exposure there is a 4.22 percent increase in admissions (CI = 1.06 to 4.75). Conclusions As with mortality studies, chronic exposure to particles is associated with substantially larger increases in hospital admissions than acute exposure and both can be detected simultaneously using our exposure models. PMID:22529923

  19. Variation in rates of hospital admission for appendicitis in Wales.

    PubMed Central

    West, R R; Carey, M J

    1978-01-01

    In a study designed to investigate the variations in rates of admission to hospital for appendicitis in Wales Hospital Activity Analysis listings were analysed according to the sex and age of the patients and the month and day of the week of admission. The incidence of hospitalisation was greatest among boys aged 10-14 and girls aged 15-19. The number of admissions was higher on weekdays than at weekends, but there were no seasonal variations. Durations of stay differed between the 17 health districts. We conclude that admission rates vary mainly because of differing hospital admission policies. Admission is not wholly governed by the sudden onset of abdominal pain; other factors include the threshold of consultation of each patient, the referral habits of general practitioners, the availability of hospital beds, and the degree to which doctors and patients expect admission. PMID:656866

  20. Lie Algebroids in Classical Mechanics and Optimal Control

    NASA Astrophysics Data System (ADS)

    Martínez, Eduardo

    2007-03-01

    We review some recent results on the theory of Lagrangian systems on Lie algebroids. In particular we consider the symplectic and variational formalism and we study reduction. Finally we also consider optimal control systems on Lie algebroids and we show how to reduce Pontryagin maximum principle.

  1. Turn Up the Volume: Uncovering Nucleus Size Control Mechanisms.

    PubMed

    Good, Matthew C

    2015-06-08

    Reporting in Developmental Cell, Hara and Merten (2015) apply the use of microfabrication and in vitro analysis in cell-free extracts to the old problem of nuclear size control. The authors make insights into the regulation of nuclear growth that potentially explain the widely reported correlation between nucleus size and cell size.

  2. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this...

  3. 14 CFR 29.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.923 Rotor drive system and control mechanism tests. (a) Endurance tests, general. Each rotor...

  4. 14 CFR 29.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.923 Rotor drive system and control mechanism tests. (a) Endurance tests, general. Each rotor...

  5. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this...

  6. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this...

  7. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this...

  8. 14 CFR 27.923 - Rotor drive system and control mechanism tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Rotor drive system and control mechanism... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.923 Rotor drive system and control mechanism tests. (a) Each part tested as prescribed in this...

  9. Snail levels control the migration mechanism of mesenchymal tumor cells

    PubMed Central

    BELGIOVINE, CRISTINA; CHIESA, GIULIO; CHIODI, ILARIA; FRAPOLLI, ROBERTA; BONEZZI, KATIUSCIA; TARABOLETTI, GIULIA; D'INCALCI, MAURIZIO; MONDELLO, CHIARA

    2016-01-01

    Cancer cells use two major types of movement: Mesenchymal, which is typical of cells of mesenchymal origin and depends on matrix metalloproteinase (MMP) activity, and amoeboid, which is characteristic of cells with a rounded shape and relies on the activity of Rho-associated kinase (ROCK). The present authors previously demonstrated that, during neoplastic transformation, telomerase-immortalized human fibroblasts (cen3tel cells) acquired a ROCK-dependent/MMP independent mechanism of invasion, mediated by the downregulation of the ROCK cellular inhibitor Round (Rnd)3/RhoE. In the present study, cen3tel transformation was also demonstrated to be paralleled by downregulation of Snail, a major determinant of the mesenchymal movement. To test whether Snail levels could determine the type of movement adopted by mesenchymal tumor cells, Snail was ectopically expressed in tumorigenic cells. It was observed that ectopic Snail did not increase the levels of typical mesenchymal markers, but induced cells to adopt an MMP-dependent mechanism of invasion. In cells expressing ectopic Snail, invasion became sensitive to the MMP inhibitor Ro 28–2653 and insensitive to the ROCK inhibitor Y27632, suggesting that, once induced by Snail, the mesenchymal movement prevails over the amoeboid one. Snail-expressing cells had a more aggressive behavior in vivo, and exhibited increased tumor growth rate and metastatic ability. These results confirm the high plasticity of cancer cells, which can adopt different types of movement in response to changes in the expression of specific genes. Furthermore, the present findings indicate that Rnd3 and Snail are possible regulators of the type of invasion mechanism adopted by mesenchymal tumor cells. PMID:27347214

  10. Snail levels control the migration mechanism of mesenchymal tumor cells.

    PubMed

    Belgiovine, Cristina; Chiesa, Giulio; Chiodi, Ilaria; Frapolli, Roberta; Bonezzi, Katiuscia; Taraboletti, Giulia; D'Incalci, Maurizio; Mondello, Chiara

    2016-07-01

    Cancer cells use two major types of movement: Mesenchymal, which is typical of cells of mesenchymal origin and depends on matrix metalloproteinase (MMP) activity, and amoeboid, which is characteristic of cells with a rounded shape and relies on the activity of Rho-associated kinase (ROCK). The present authors previously demonstrated that, during neoplastic transformation, telomerase-immortalized human fibroblasts (cen3tel cells) acquired a ROCK-dependent/MMP independent mechanism of invasion, mediated by the downregulation of the ROCK cellular inhibitor Round (Rnd)3/RhoE. In the present study, cen3tel transformation was also demonstrated to be paralleled by downregulation of Snail, a major determinant of the mesenchymal movement. To test whether Snail levels could determine the type of movement adopted by mesenchymal tumor cells, Snail was ectopically expressed in tumorigenic cells. It was observed that ectopic Snail did not increase the levels of typical mesenchymal markers, but induced cells to adopt an MMP-dependent mechanism of invasion. In cells expressing ectopic Snail, invasion became sensitive to the MMP inhibitor Ro 28-2653 and insensitive to the ROCK inhibitor Y27632, suggesting that, once induced by Snail, the mesenchymal movement prevails over the amoeboid one. Snail-expressing cells had a more aggressive behavior in vivo, and exhibited increased tumor growth rate and metastatic ability. These results confirm the high plasticity of cancer cells, which can adopt different types of movement in response to changes in the expression of specific genes. Furthermore, the present findings indicate that Rnd3 and Snail are possible regulators of the type of invasion mechanism adopted by mesenchymal tumor cells.

  11. Molecular mechanisms controlling proton pumping by bacteriorhodopsin. Final report

    SciTech Connect

    Crouch, Rosalie K.; Ebrey, Thomas G.

    2000-02-10

    Bacteriorhodopsin (bR) is the simplest biological system for the transduction of light energy. Light energy is directly converted to transmembrane proton gradient by a single, small membrane protein. The extraordinary stability of bR makes it an outstanding subject for bioenergetic studies. This project has focused on the role of interactions between key residues of the pigment involved in light-induced proton transfer. Methods to estimate the strength of these interactions and their correlation with the rate and efficiency of proton transfer have been developed. The concept of the coupling of the protonation states of key groups has been applied to individual steps of the proton transfer with the ultimate goal of understanding on the molecular level the driving forces for proton transport and the pathway of the transported proton in bT. The mechanism of light-induced proton release, uptake and the mechanism of recovery of initial state of bT has been examined. The experiments were performed with genetically engineered, site-specific mutants of bR. This has enabled us to characterize the role of individual amino acid residues in bR. Time resolved and low temperature absorption spectroscopy and light-induced photocurrent measurements were used in order to study the photochemical cycle and proton transfer in mutant pigments. Chemical modification and crosslinking of both the specific amino acids to the chromophore or to other amino acids were used to elucidate the role of light-induced conformational changes in the photocycle and the structure of the protein in the ground state. The results of this project provided new knowledge on the architecture of the proton transfer pathways inside the protein, on the mechanism of proton release in bR, and on the role of specific amino acid residues in the structure and function of bR.

  12. Eco-hydrological feedback mechanisms control ecological services in wetlands

    NASA Astrophysics Data System (ADS)

    Coletti, J.; Hinz, C.; Vogwill, R.; Tareque, H.; Hipsey, M. R.

    2011-12-01

    Wetland ecosystems contain various feedback mechanisms between their abiotc and biotic components. The feedbacks are triggered by climate and propagate into patterns of environment partitioning based on distinct zones of hydrological function that vary in time and space. This partitioning co-evolves with vegetation, defines carbon metabolism and creates niches that govern patterns of flora and fauna abundance and distribution. Using a minimalistic model for wetland eco-hydrology, we explore vegetation adaptation to climate variability and the net metabolism of a wetland ecosystem given a range of climate conditions. We then apply the model to characterize the changes in niche habitat availability for a tortoise population endangered by a drying climate.

  13. Biochemical Mechanisms Controlling Terminal Electron Transfer in Geobacter sulfurreducens

    NASA Astrophysics Data System (ADS)

    Helmus, R.; Liermann, L. J.; Brantley, S. L.; Tien, M.

    2009-04-01

    The ability of Geobacter sulfurreducens to use a variety of metals as terminal electron acceptors (TEAs) for cellular respiration makes it attractive for use in bioremediation and implies its importance to mineral cycling in the environment. This study is aimed at understanding the biochemical mechanisms that allow Geobacter sulfurreducens to use soluble and insoluble iron and manganese forms as TEAs for cellular respiration and is the first of its kind to address the kinetics of manganese use as a TEA by G. sulfurreducens. First, G. sulfurreducens was conditioned to grow on various soluble and insoluble iron and manganese forms. G. sulfurreducens demonstrated enhanced growth rates when cultured using soluble TEAs compared with insoluble TEAs. However, the lower growth rate on insoluble iron compared with soluble iron was observed concomitantly with a 1-2 log lower cell density in stationary phase in insoluble iron cultures and a lower growth yield per electron donor used in log growth phase. Furthermore, the growth yield per electron was similar with both soluble and insoluble iron. These results suggest that the net amount of energy available for biomass production achieved from reducing insoluble iron is lower than with soluble iron, which may be due to a different biochemical mechanism catalyzing the electron transfer to TEA dependent upon the solubility of the TEA. One scenario consistent with this notion is that protein(s) in the outer membrane of G. sulfurreducens that transfers electrons to insoluble TEAs does so in a manner that uncouples electron flow from the proton pump in the cellular membrane, similar to what we have observed with Shewanella oneidensis MR-1. Both the growth rate and growth yield of G. sulfurreducens on insoluble manganese were higher than on insoluble iron, indicating that there is a difference in the flow of electrons to the TEA in these two situations. While the different redox potentials of these elements may affect these values

  14. Mechanical control over valley magnetotransport in strained graphene

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Zhang, Shengli; Liu, Daqing

    2016-05-01

    Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov-de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm "valleytronics" applications.

  15. Cognitive Control Mechanisms, Emotion & Memory: A neural perspective with implications for psychopathology

    PubMed Central

    Banich, Marie T.; Mackiewicz, Kristen L.; Depue, Brendan E.; Whitmer, Anson; Miller, Gregory A.; Heller, Wendy

    2009-01-01

    In this paper we provide a focused review of the literature examining neural mechanisms involved in cognitive control over memory processes that can influence, and in turn are influenced, by emotional processes. The review is divided into two parts, the first focusing on working memory and the second on long-term memory. With regard to working memory, we discuss the neural bases of 1) control mechanisms that can select against distracting emotional information, 2) mechanisms that can regulate emotional reactions or responses, 3) how mood state influences cognitive control, and 4) individual differences in control mechanisms. For long-term memory, we briefly review 1) the neural substrates of emotional memory, 2) the cognitive and neural mechanisms that are involved in controlling emotional memories and 3) how these systems are altered in post-traumatic stress disorder. Finally, we consider tentative generalizations that can be drawn from this relatively unexplored conjunction of research endeavors. PMID:18948135

  16. Synaptic mechanisms underlying cholinergic control of thalamic reticular nucleus neurons

    PubMed Central

    Beierlein, Michael

    2014-01-01

    Neuronal networks of the thalamus are the target of extensive cholinergic projections from the basal forebrain and the brainstem. Activation of these afferents can regulate neuronal excitability, transmitter release, and firing patterns in thalamic networks, thereby altering the flow of sensory information during distinct behavioural states. However, cholinergic regulation in the thalamus has been primarily examined by using receptor agonist and antagonist, which has precluded a detailed understanding of the spatiotemporal dynamics that govern cholinergic signalling under physiological conditions. This review summarizes recent studies on cholinergic synaptic transmission in the thalamic reticular nucleus (TRN), a brain structure intimately involved in the control of sensory processing and the generation of rhythmic activity in the thalamocortical system. This work has shown that acetylcholine (ACh) released from individual axons can rapidly and reliably activate both pre- and postsynaptic cholinergic receptors, thereby controlling TRN neuronal activity with high spatiotemporal precision. PMID:24973413

  17. A mechanism for sensory re-weighting in postural control

    PubMed Central

    Mahboobin, Arash; Loughlin, Patrick; Atkeson, Chris; Redfern, Mark

    2016-01-01

    A key finding of human balance experiments has been that the integration of sensory information utilized for postural control appears to be dynamically regulated to adapt to changing environmental conditions and the available sensory information, a process referred to as “sensory re-weighting.” We propose a postural control model that includes automatic sensory re-weighting. This model is an adaptation of a previously reported model of sensory feedback that included manual sensory re-weighting. The new model achieves sensory re-weighting that is physiologically plausible and readily implemented. Model simulations are compared to previously reported experimental results to demonstrate the automated sensory reweighting strategy of the modified model. On the whole, the postural sway time series generated by the model with automatic sensory re-weighting show good agreement with experimental data, and are capable of producing patterns similar to those observed experimentally. PMID:19326162

  18. Abiotic and Biotic Mechanisms Controlling In Situ Remediation of NDMA

    DTIC Science & Technology

    2009-05-01

    Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions...information if it does not display a currently valid OMB control number. 1 . REPORT DATE MAY 2009 2. REPORT TYPE 3. DATES COVERED 00-00-2009 to 00...aqueous) did not promote NDMA degradation; an iron oxide or 2: 1 clay was needed for electron transfer. NDMA degradation to DMA under iron-reducing

  19. Controlled Mechanical Cracking of Metal Films Deposited on Polydimethylsiloxane (PDMS)

    PubMed Central

    Polywka, Andreas; Stegers, Luca; Krauledat, Oliver; Riedl, Thomas; Jakob, Timo; Görrn, Patrick

    2016-01-01

    Stretchable large area electronics conform to arbitrarily-shaped 3D surfaces and enables comfortable contact to the human skin and other biological tissue. There are approaches allowing for large area thin films to be stretched by tens of percent without cracking. The approach presented here does not prevent cracking, rather it aims to precisely control the crack positions and their orientation. For this purpose, the polydimethylsiloxane (PDMS) is hardened by exposure to ultraviolet radiation (172 nm) through an exposure mask. Only well-defined patterns are kept untreated. With these soft islands cracks at the hardened surface can be controlled in terms of starting position, direction and end position. This approach is first investigated at the hardened PDMS surface itself. It is then applied to conductive silver films deposited from the liquid phase. It is found that statistical (uncontrolled) cracking of the silver films can be avoided at strain below 35%. This enables metal interconnects to be integrated into stretchable networks. The combination of controlled cracks with wrinkling enables interconnects that are stretchable in arbitrary and changing directions. The deposition and patterning does not involve vacuum processing, photolithography, or solvents.

  20. Short-Term Effects of Coarse Particulate Matter on Hospital Admissions for Cardiovascular Diseases: A Case-Crossover Study in a Tropical City.

    PubMed

    Chen, Ying-Chen; Weng, Yi-Hao; Chiu, Ya-Wen; Yang, Chun-Yuh

    2015-01-01

    This study was undertaken to determine whether there was an association between coarse particles (PM2.5-10) levels and frequency of hospital admissions for cardiovascular diseases (CVD) in Kaohsiung, Taiwan. Hospital admissions for CVD, including ischemic heart disease (IHD), stroke, congestive heart failure (CHF), and arrhythmias, and ambient air pollution data levels for Kaohsiung were obtained for the period 2006-2010. The relative risk of hospital admissions for CVD was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single-pollutant model (without adjustment for other pollutants), increased rates of admissions for CVD were significantly associated with higher coarse PM levels only on cool days (< 25°C), with a 10-μg/m(3) elevation in PM2.5-10 concentrations associated with a 3% (95% CI = 2-4%) rise in IHD admissions, 5% (95% CI = 4-6%) increase in stroke admissions, 3% (95% CI = 1-6%) elevation in CHF admissions, and 3% (95% CI = 0-6%) rise in arrhythmias admissions. No significant associations were found between coarse particle levels and number of hospital admissions for CVD on warm days. In the two-pollutant models, PM2.5-10 levels remained significantly correlated with higher rate of CVD admissions even controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, or ozone on cool days. Compared to the effect estimate associated with a 10-μg/m(3) increase in PM2.5 levels, effect estimates of frequency of CVD-related admissions associated with a 10-μg/m(3) rise in coarse PM levels were weaker. This study provides evidence that higher levels of PM2.5-10 enhance the risk of hospital admissions for CVD.

  1. Development of passive-controlled HUB (teetered brake & damper mechanism) of horizontal axis wind turbine

    SciTech Connect

    Shimizu, Yukimaru; Kamada, Yasunari; Maeda, Takao

    1997-12-31

    For the purpose of the improvement of reliability of the Mega-Watt wind turbine, this paper indicates the development of an original mechanism for the passive-controlled hub, which has the effects of braking and damping on aerodynamic forces. This mechanism is useful for variable speed control of the large wind turbine. The passive-controlled hub is the combination of two mechanisms. One is the passive-teetered and damping mechanism, and the other is the passive-variable-pitch mechanism. These mechanism are carried out by the combination of the teetering and feathering motions. When the wind speed exceeds the rated wind speed, the blade is passively teetered in a downwind direction and, simultaneously, a feathering mechanism, which is linked to the teetering mechanism through a connecting rods, is activated. Testing of the model horizontal axis wind turbine in a wind tunnel showed that the passive-controlled hub mechanism can suppress the over-rotational speed of the rotor. By the application of the passive-controlled hub mechanism, the maximum rotor speed is reduced to about 60%.

  2. Air pollution and hospital admissions for asthma in a tropical city: Kaohsiung, Taiwan

    SciTech Connect

    Shang-Shyue Tsai; Meng-Hsuan Cheng; Hui-Fen Chiu; Trong-Neng Wu; Chun-Yuh Yang

    2006-07-15

    This study was undertaken to determine whether there is an association between air pollutants levels and hospital admissions for asthma in Kaohsiung, Taiwan. Hospital admissions for asthma and ambient air pollution data for Kaohsiung were obtained for the period from 1996 through 2003. The relative risk of hospital admission was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. In the single-pollutant models, on warm days ({>=}25{sup o}C) statistically significant positive associations were found in all pollutants except sulfur dioxide. On cool days ({<=} 25{sup o}C) all pollutants were significantly associated with asthma admissions. For the two pollutant models, CO and O{sub 3} were significant in combination with each of the other four pollutants on warm days. On cool days NO{sub 2} remained statistically significant in all the two-pollutant models. This study provides evidence that higher levels of ambient pollutants increase the risk of hospital admissions for asthma.

  3. Sonolytic degradation of dimethoate: kinetics, mechanisms and toxic intermediates controlling.

    PubMed

    Yao, Juan-Juan; Hoffmann, Michael R; Gao, Nai-Yun; Zhang, Zhi; Li, Lei

    2011-11-15

    The sonolytic degradation of aqueous solutions of dimethoate, O,O-dimethyl S-[2-(methylamino)-2-oxoethyl]dithiophosphate, was examined. Optimal degradation rates were obtained at 619 kHz for continuous sonolysis and 406 kHz for pulse sonolysis. The primary pathways for degradation include hydroxyl radical oxidation, hydrolysis and pyrolysis on collapsing cavitation bubble interfaces. Reaction mechanisms coupled with the corresponding kinetic models are proposed to reproduce the observed concentration versus time profiles for dimethoate, omethoate and N-(methyl) mercaptoacetamide during sonolysis. The oxidation and hydrolysis of dimethoate and omethoate occurred at the water-bubble interface was the rate-determining step for sonolytic overall degradation of dimethoate. More than 90% toxicity of dimethoate was reduced within 45 min ultrasonic irradiation. Ferrous ion at micro molar level can significantly enhance the sonolytic degradation of dimethoate and effectively reduce the yields of toxic intermediate omethoate.

  4. Control of mechanically activated polymersome fusion: Factors affecting fusion

    DOE PAGES

    Henderson, Ian M.; Paxton, Walter F.

    2014-12-15

    Previously we have studied the mechanically-activated fusion of extruded (200 nm) polymer vesicles into giant polymersomes using agitation in the presence of salt. In this study we have investigated several factors contributing to this phenomenon, including the effects of (i) polymer vesicle concentration, (ii) agitation speed and duration, and iii) variation of the salt and its concentration. It was found that increasing the concentration of the polymer dramatically increases the production of giant vesicles through the increased collisions of polymersomes. Our investigations also found that increasing the frequency of agitation increased the efficiency of fusion, though ultimately limited the sizemore » of vesicle which could be produced due to the high shear involved. Finally it was determined that salt-mediation of the fusion process was not limited to NaCl, but is instead a general effect facilitated by the presence of solvated ionic compounds, albeit with different salts initiating fusion at different concentration.« less

  5. Control of mechanically activated polymersome fusion: Factors affecting fusion

    SciTech Connect

    Henderson, Ian M.; Paxton, Walter F.

    2014-12-15

    Previously we have studied the mechanically-activated fusion of extruded (200 nm) polymer vesicles into giant polymersomes using agitation in the presence of salt. In this study we have investigated several factors contributing to this phenomenon, including the effects of (i) polymer vesicle concentration, (ii) agitation speed and duration, and iii) variation of the salt and its concentration. It was found that increasing the concentration of the polymer dramatically increases the production of giant vesicles through the increased collisions of polymersomes. Our investigations also found that increasing the frequency of agitation increased the efficiency of fusion, though ultimately limited the size of vesicle which could be produced due to the high shear involved. Finally it was determined that salt-mediation of the fusion process was not limited to NaCl, but is instead a general effect facilitated by the presence of solvated ionic compounds, albeit with different salts initiating fusion at different concentration.

  6. Impeller leakage flow modeling for mechanical vibration control

    NASA Technical Reports Server (NTRS)

    Palazzolo, Alan B.

    1996-01-01

    HPOTP and HPFTP vibration test results have exhibited transient and steady characteristics which may be due to impeller leakage path (ILP) related forces. For example, an axial shift in the rotor could suddenly change the ILP clearances and lengths yielding dynamic coefficient and subsequent vibration changes. ILP models are more complicated than conventional-single component-annular seal models due to their radial flow component (coriolis and centrifugal acceleration), complex geometry (axial/radial clearance coupling), internal boundary (transition) flow conditions between mechanical components along the ILP and longer length, requiring moment as well as force coefficients. Flow coupling between mechanical components results from mass and energy conservation applied at their interfaces. Typical components along the ILP include an inlet seal, curved shroud, and an exit seal, which may be a stepped labyrinth type. Von Pragenau (MSFC) has modeled labyrinth seals as a series of plain annular seals for leakage and dynamic coefficient prediction. These multi-tooth components increase the total number of 'flow coupled' components in the ILP. Childs developed an analysis for an ILP consisting of a single, constant clearance shroud with an exit seal represented by a lumped flow-loss coefficient. This same geometry was later extended to include compressible flow. The objective of the current work is to: supply ILP leakage-force impedance-dynamic coefficient modeling software to MSFC engineers, base on incompressible/compressible bulk flow theory; design the software to model a generic geometry ILP described by a series of components lying along an arbitrarily directed path; validate the software by comparison to available test data, CFD and bulk models; and develop a hybrid CFD-bulk flow model of an ILP to improve modeling accuracy within practical run time constraints.

  7. Growth laws and mechanisms of global control in bacteria

    NASA Astrophysics Data System (ADS)

    Scott, Matthew

    2009-03-01

    The growth laws of Schaechter, Maaløe and Kjeldgaard are among the most striking discoveries in bacterial growth physiology: cell composition (mass/cell, RNA/cell, etc.) is a simple function of growth rate alone -- irrespective of how that growth rate is established. I will review the growth laws, and discuss recent experiments that have uncovered new laws. A systems-level mathematical model is developed that suggests the growth laws arise from the partitioning of the protein synthesizing machinery of the cell (the ribosomes), and furthermore indicates a deep connection between growth rate control and central metabolism.

  8. Local Medicaid Home- and Community-Based Services Spending and Nursing Home Admissions of Younger Adults

    PubMed Central

    Keohane, Laura; Mor, Vincent

    2014-01-01

    We used fixed-effect models to examine the relationship between local spending on home- and community-based services (HCBSs) for cash-assisted Medicaid-only disabled (CAMOD) adults and younger adult admissions to nursing homes in the United States during 2001 through 2008, with control for facility and market characteristics and secular trends. We found that increased CAMOD Medicaid HCBS spending at the local level is associated with decreased admissions of younger adults to nursing homes. Our findings suggest that states’ efforts to expand HCBS for this population should continue. PMID:25211711

  9. Local Medicaid home- and community-based services spending and nursing home admissions of younger adults.

    PubMed

    Thomas, Kali S; Keohane, Laura; Mor, Vincent

    2014-11-01

    We used fixed-effect models to examine the relationship between local spending on home- and community-based services (HCBSs) for cash-assisted Medicaid-only disabled (CAMOD) adults and younger adult admissions to nursing homes in the United States during 2001 through 2008, with control for facility and market characteristics and secular trends. We found that increased CAMOD Medicaid HCBS spending at the local level is associated with decreased admissions of younger adults to nursing homes. Our findings suggest that states' efforts to expand HCBS for this population should continue.

  10. Wavelet frames and admissibility in higher dimensions

    NASA Astrophysics Data System (ADS)

    Führ, Hartmut

    1996-12-01

    This paper is concerned with the relations between discrete and continuous wavelet transforms on k-dimensional Euclidean space. We start with the construction of continuous wavelet transforms with the help of square-integrable representations of certain semidirect products, thereby generalizing results of Bernier and Taylor. We then turn to frames of L2(Rk) and to the question, when the functions occurring in a given frame are admissible for a given continuous wavelet transform. For certain frames we give a characterization which generalizes a result of Daubechies to higher dimensions.

  11. Racial disparities in receiving total hip/knee replacement surgery: the effect of hospital admission sources.

    PubMed

    Chen, Jie; Rizzo, John A; Parasuraman, Shreekant; Gunnarsson, Candace

    2013-02-01

    Using a nationally-representative inpatient care dataset (the HCUP National Inpatient Sample from 2002 to 2007) we examined racial disparities in receiving total hip replacement (THR) and total knee replacement (TKR) surgeries. Multivariable logistic regression models revealed that racial minorities were significantly less likely to receive THR or TKR than Whites, controlling for patients' hospital admission source and hospital characteristics. Employing Blinder-Oaxaca decomposition techniques, we found that observed difference in population characteristics explained 55%-67% and 78% of the racial disparities in THR and TKR, respectively. Differences in patients' hospital admission source emerged as the major individual factor associated with these disparities, explaining 57%-77% of racial disparities in THR and 26%-50% of racial disparities in TKR. This study suggests that substantive racial and ethnic disparities exist in utilization of THR and TKR surgery. Observed population characteristics accounted for most of these differences, with hospital admission source being the key factor.

  12. Controlling mechanisms in directional growth of aggregated archaeal cells.

    PubMed

    Milkevych, Viktor; Batstone, Damien J

    2014-12-28

    Members of the family Methanosarcinaceae are important archaeal representatives due to their broad functionality, ubiquitous presence, and functionality in harsh environments. A key characteristic is their multicellular (packet) morphology represented by aggregates of spatially confined cells. This morphology is driven by directed growth of cells in confinement with sequential variation in growth direction. To further understand why spatially confined Methanosarcina cells (and in general, confined prokaryotes) change their direction of growth during consecutive growth-division stages, and how a particular cell senses its wall topology and responds to changes on it a theoretical model for stress dependent growth of aggregated archaeal cells was developed. The model utilizes a confined elastic shell representation of aggregated archaeal cell and is derived based on a work-energy principle. The growth law takes into account the fine structure of archaeal cell wall, polymeric nature of methanochondroitin layer, molecular-biochemical processes and is based on thermodynamic laws. The developed model has been applied to three typical configurations of aggregated cell in 3D. The developed model predicted a geometry response with delayed growth of aggregated archaeal cells explained from mechanistic principles, as well as continuous changes in direction of growth during the consecutive growth-division stages. This means that cell wall topology sensing and growth anisotropy can be predicted using simple cellular mechanisms without the need for dedicated cellular machinery.

  13. Redox Control of Microglial Function: Molecular Mechanisms and Functional Significance

    PubMed Central

    McBean, Gethin; Cindric, Marina; Egea, Javier; López, Manuela G.; Rada, Patricia; Zarkovic, Neven

    2014-01-01

    Abstract Neurodegenerative diseases are characterized by chronic microglial over-activation and oxidative stress. It is now beginning to be recognized that reactive oxygen species (ROS) produced by either microglia or the surrounding environment not only impact neurons but also modulate microglial activity. In this review, we first analyze the hallmarks of pro-inflammatory and anti-inflammatory phenotypes of microglia and their regulation by ROS. Then, we consider the production of reactive oxygen and nitrogen species by NADPH oxidases and nitric oxide synthases and the new findings that also indicate an essential role of glutathione (γ-glutamyl-l-cysteinylglycine) in redox homeostasis of microglia. The effect of oxidant modification of macromolecules on signaling is analyzed at the level of oxidized lipid by-products and sulfhydryl modification of microglial proteins. Redox signaling has a profound impact on two transcription factors that modulate microglial fate, nuclear factor kappa-light-chain-enhancer of activated B cells, and nuclear factor (erythroid-derived 2)-like 2, master regulators of the pro-inflammatory and antioxidant responses of microglia, respectively. The relevance of these proteins in the modulation of microglial activity and the interplay between them will be evaluated. Finally, the relevance of ROS in altering blood brain barrier permeability is discussed. Recent examples of the importance of these findings in the onset or progression of neurodegenerative diseases are also discussed. This review should provide a profound insight into the role of redox homeostasis in microglial activity and help in the identification of new promising targets to control neuroinflammation through redox control of the brain. Antioxid. Redox Signal. 21, 1766–1801. PMID:24597893

  14. Noise in biological systems: pros, cons, and mechanisms of control.

    PubMed

    Pilpel, Yitzhak

    2011-01-01

    Genetic regulatory circuits are often regarded as precise machines that accurately determine the level of expression of each protein. Most experimental technologies used to measure gene expression levels are incapable of testing and challenging this notion, as they often measure levels averaged over entire populations of cells. Yet, when expression levels are measured at the single cell level of even genetically identical cells, substantial cell-to-cell variation (or "noise") may be observed. Sometimes different genes in a given genome may display different levels of noise; even the same gene, expressed under different environmental conditions, may display greater cell-to-cell variability in specific conditions and more tight control in other situations. While at first glance noise may seem to be an undesired property of biological networks, it might be beneficial in some cases. For instance, noise will increase functional heterogeneity in a population of microorganisms facing variable, often unpredictable, environmental changes, increasing the probability that some cells may survive the stress. In that respect, we can speculate that the population is implementing a risk distribution strategy, long before genetic heterogeneity could be acquired. Organisms may have evolved to regulate not only the averaged gene expression levels but also the extent of allowed deviations from such an average, setting it at the desired level for every gene under each specific condition. Here we review the evolving understanding of noise, its molecular underpinnings, and its effect on phenotype and fitness--when it can be detrimental, beneficial, or neutral and which regulatory tools eukaryotic cells may use to optimally control it.

  15. Redox control of microglial function: molecular mechanisms and functional significance.

    PubMed

    Rojo, Ana I; McBean, Gethin; Cindric, Marina; Egea, Javier; López, Manuela G; Rada, Patricia; Zarkovic, Neven; Cuadrado, Antonio

    2014-10-20

    Neurodegenerative diseases are characterized by chronic microglial over-activation and oxidative stress. It is now beginning to be recognized that reactive oxygen species (ROS) produced by either microglia or the surrounding environment not only impact neurons but also modulate microglial activity. In this review, we first analyze the hallmarks of pro-inflammatory and anti-inflammatory phenotypes of microglia and their regulation by ROS. Then, we consider the production of reactive oxygen and nitrogen species by NADPH oxidases and nitric oxide synthases and the new findings that also indicate an essential role of glutathione (γ-glutamyl-l-cysteinylglycine) in redox homeostasis of microglia. The effect of oxidant modification of macromolecules on signaling is analyzed at the level of oxidized lipid by-products and sulfhydryl modification of microglial proteins. Redox signaling has a profound impact on two transcription factors that modulate microglial fate, nuclear factor kappa-light-chain-enhancer of activated B cells, and nuclear factor (erythroid-derived 2)-like 2, master regulators of the pro-inflammatory and antioxidant responses of microglia, respectively. The relevance of these proteins in the modulation of microglial activity and the interplay between them will be evaluated. Finally, the relevance of ROS in altering blood brain barrier permeability is discussed. Recent examples of the importance of these findings in the onset or progression of neurodegenerative diseases are also discussed. This review should provide a profound insight into the role of redox homeostasis in microglial activity and help in the identification of new promising targets to control neuroinflammation through redox control of the brain.

  16. 46 CFR 160.133-15 - Production inspections, tests, quality control, and conformance of release mechanisms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., tests, quality control, and conformance of release mechanisms. (a) Unless the Commandant directs.... The manufacturer must— (1) Institute a quality control procedure to ensure that all production release... 46 Shipping 6 2012-10-01 2012-10-01 false Production inspections, tests, quality control,...

  17. Mechanism and Control of Solanum lycocarpum Seed Germination

    PubMed Central

    Pinto, Lilian V. A.; Da silva, Edvaldo A. A.; Davide, Antonio C.; De Jesus, Valquíria A. Mendes; Toorop, Peter E.; Hilhorst, Henk W. M.

    2007-01-01

    Background and Aims Solanaceae seed morphology and physiology have been widely studied but mainly in domesticated crops. The present study aimed to compare the seed morphology and the physiology of germination of Solanum lycocarpum, an important species native to the Brazilian Cerrado, with two species with endospermic seeds, tomato and coffee. Methods Morphological parameters of fruits and seeds were determined by microscopy. Germination was monitored for 40 d under different temperature regimes. Endosperm digestion and resistance, with endo-β-mannanase activity and required force to puncture the endosperm cap as respective markers, were measured during germination in water and in abscisic acid. Key Results Fruits of S. lycocarpum contain dormant seeds before natural dispersion. The best germination condition found was a 12-h alternating light/dark and high/low (20/30 °C) temperature cycle, which seemed to target properties of the endosperm cap. The endosperm cap contains 7–8 layers of elongated polygonal cells and is predestined to facilitate radicle protrusion. The force required to puncture the endosperm cap decreased in two stages during germination and showed a significant negative correlation with endo-β-mannanase activity. As a result of the thick endosperm cap, the puncture force was significantly higher in S. lycocarpum than in tomato and coffee. Endo-β-mannanase activity was detected in the endosperm cap prior to radicle protrusion. Abscisic acid inhibited germination, increase of embryo weight during imbibition, the second stage of weakening of the endosperm cap and of endo-β-mannanase activity in the endosperm cap. Conclusions The germination mechanism of S. lycocarpum bears resemblance to that of tomato and coffee seeds. However, quantitative differences were observed in embryo pressure potential, endo-β-mannanase activity and endosperm cap resistance that were related to germination rates across the three species. PMID:17855380

  18. An Action-Based Fine-Grained Access Control Mechanism for Structured Documents and Its Application

    PubMed Central

    Su, Mang; Li, Fenghua; Tang, Zhi; Yu, Yinyan; Zhou, Bo

    2014-01-01

    This paper presents an action-based fine-grained access control mechanism for structured documents. Firstly, we define a describing model for structured documents and analyze the application scenarios. The describing model could support the permission management on chapters, pages, sections, words, and pictures of structured documents. Secondly, based on the action-based access control (ABAC) model, we propose a fine-grained control protocol for structured documents by introducing temporal state and environmental state. The protocol covering different stages from document creation, to permission specification and usage control are given by using the Z-notation. Finally, we give the implementation of our mechanism and make the comparisons between the existing methods and our mechanism. The result shows that our mechanism could provide the better solution of fine-grained access control for structured documents in complicated networks. Moreover, it is more flexible and practical. PMID:25136651

  19. Development of a Maximum Admissions Index for Freshman Admissions to the University of Washington.

    ERIC Educational Resources Information Center

    Lunneborg, Clifford E.

    A new technique has been developed for admitting new freshman students at the University of Washington. Previously, an Admissions Index (AI) was used, in which the high school grade point average (HSGPA) was assigned twice the weight of the composite verbal and quantitative scores from the Washington Pre-College Test Battery (WPC). To offset the…

  20. An Evaluation of the Pharmacy College Admissions Test as a Tool for Pharmacy College Admissions Committees.

    ERIC Educational Resources Information Center

    Kelley, Katherine A.; Secnik, Kristina; Boye, Mark E.

    2001-01-01

    Investigated the capacity of the Pharmacy College Admissions Test (PCAT) to predict success in pharmacy school. Found demographic differences in PCAT scores, and that the PCAT used in combination with pre-pharmacy grade point average is meaningful in assessing applicants to pharmacy school; applicants with PCAT composite percentile scores below 40…