Holding Firm: Power, Push-Back, and Opportunities in Navigating the Liminal Space of Critical Qualitative Health Research.

Science.gov (United States)

Hart, Corinne; Poole, Jennifer M; Facey, Marcia E; Parsons, Janet A

2017-10-01

Critical qualitative health researchers typically occupy and navigate liminal academic spaces and statuses, with one foot planted in the arts and social sciences and the other in biomedical science. We are at once marginalized and empowered, and this liminality presents both challenges and opportunities. In this article, we draw on our experiences of being (often the lone) critical qualitative health scholars on thesis advisory committees and dissertation examinations, as well as our experiences of publishing and securing funding, to illuminate how power and knowledge relations create conditions that shape the nature of our roles. We share strategies we have developed for standing our theoretical and methodological ground. We discuss how we use the power of our liminality to hold firm, push back, and push forward, to ensure that critical qualitative research is not further relegated to the margins and its quality and integrity sustained.

Nuclear fuel cycle: research and development and push technologies

International Nuclear Information System (INIS)

Oliveira, Wagner dos Santos

2002-01-01

The scope of this work is to show the importance of 'push technologies in the development of the Nuclear Fuel Cycle more specifically the so called 'Projeto Conversao' PROCON. This R and D activities lead to the design of special equipment, new metallic and polymer materials. (author)

Target-oriented retrieval of subsurface wave fields - Pushing the resolution limits in seismic imaging

Science.gov (United States)

Vasconcelos, Ivan; Ozmen, Neslihan; van der Neut, Joost; Cui, Tianci

2017-04-01

Travelling wide-bandwidth seismic waves have long been used as a primary tool in exploration seismology because they can probe the subsurface over large distances, while retaining relatively high spatial resolution. The well-known Born resolution limit often seems to be the lower bound on spatial imaging resolution in real life examples. In practice, data acquisition cost, time constraints and other factors can worsen the resolution achieved by wavefield imaging. Could we obtain images whose resolution beats the Born limits? Would it be practical to achieve it, and what are we missing today to achieve this? In this talk, we will cover aspects of linear and nonlinear seismic imaging to understand elements that play a role in obtaining "super-resolved" seismic images. New redatuming techniques, such as the Marchenko method, enable the retrieval of subsurface fields that include multiple scattering interactions, while requiring relatively little knowledge of model parameters. Together with new concepts in imaging, such as Target-Enclosing Extended Images, these new redatuming methods enable new targeted imaging frameworks. We will make a case as to why target-oriented approaches to reconstructing subsurface-domain wavefields from surface data may help in increasing the resolving power of seismic imaging, and in pushing the limits on parameter estimation. We will illustrate this using a field data example. Finally, we will draw connections between seismic and other imaging modalities, and discuss how this framework could be put to use in other applications

f-electron systems: pushing band theory

International Nuclear Information System (INIS)

Koelling, D.D.

1991-01-01

The f-electron orbitrals have always been the ''incomplete atomic shells acting as local moments, and weakly interacting with the remaining electronic structure'' in the minds of most people. So examining them using a band theory where one views them as itinerant was once - and to some extent even today still is - considered with some skepticism. Nonetheless, a very significant community has successfully utilized band theory as a probe of the electronic structure of the appropriate actinides and rare earths. Those people actually using the approach would be the first to declare that it is not the whole solution. Instead, one is pushing and even exceeding its limit of applicability. However, the apropriate procedure is to push the model consistently to its limits, patch where possible, and then look to see where discrepancies remain. I propose to offer a selected review of past developments (emphasizing the career to data of A.J. Freeman in this area), offer a list of interesting puzzles for the future, and then make some guesses as to the techniques one might want to use. (orig.)

Push Attack: Binding Virtual and Real Identities Using Mobile Push Notifications

Directory of Open Access Journals (Sweden)

Pierpaolo Loreti

2018-01-01

Full Text Available Popular mobile apps use push notifications extensively to offer an “always connected” experience to their users. Social networking apps use them as a real-time channel to notify users about new private messages or new social interactions (e.g., friendship request, tagging, etc.. Despite the cryptography used to protect these communication channels, the strict temporal binding between the actions that trigger the notifications and the reception of the notification messages in the mobile device may represent a privacy issue. In this work, we present the push notification attack designed to bind the physical owners of mobile devices with their virtual identities, even if pseudonyms are used. In an online attack, an active attacker triggers a push notification and captures the notification packets that transit in the network. In an offline attack, a passive attacker correlates the social network activity of a user with the received push notification. The push notification attack bypasses the standard ways of protecting user privacy based on the network layer by operating at the application level. It requires no additional software on the victim’s mobile device.

iOS 5 Programming Pushing the Limits Developing Extraordinary Mobile Apps for Apple IPhone, IPad, and IPod Touch

CERN Document Server

Napier, Rob

2011-01-01

Open the door to endless new app development possibilities Pushing the Limits with iOS 5 Programming is an expert guide for developers aiming to create unique applications for Apple's iPad 2, iPhone, and the iPod Touch. Preparing you for the release of for the newest version the Apple iPhone SDK, iOS 5 coming out this fall, this text goes beyond the basics to keep you ahead of the technology curve and spark your innovative nature to create seamless, functional, and fun apps. With a focus on advanced techniques for app development, you will learn to differentiate your apps from all the rest. W

Effect of spontaneous pushing versus Valsalva pushing in the second stage of labour on mother and fetus: a systematic review of randomised trials.

Science.gov (United States)

Prins, M; Boxem, J; Lucas, C; Hutton, E

2011-05-01

To critically evaluate any benefit or harm for the mother and her baby of Valsalva pushing versus spontaneous pushing in the second stage of labour. Electronic databases from MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials were systematically searched (last search May 2010). The reference lists of retrieved studies were searched by hand and an internet hand search of master theses and dissertations was performed. No date or language restriction was used. Randomised controlled trials that compared instructed pushing with spontaneous pushing in the second stage of labour were considered. Studies were evaluated independently for methodological quality and appropriateness for inclusion by two authors (MP and JB). The primary outcome was instrumental/operative delivery. Other outcomes were length of labour, any perineal repair, bladder function, maternal satisfaction. Infant outcomes included low Apgar score pushing technique (three studies; 425 women; mean difference 18.59 minutes; 95% CI 0.46-36.73 minutes). Neonatal outcomes did not differ significantly. Urodynamic factors measured 3 months postpartum were negatively affected by Valsalva pushing. Measures of first urge to void and bladder capacity were decreased (one study; 128 women; mean difference respectively 41.50 ml, 95% CI 8.40-74.60, and 54.60 ml, 95% CI 13.31-95.89). The evidence from our review does not support the routine use of Valsalva pushing in the second stage of labour. The Valsalva pushing method has a negative effect on urodynamic factors according to one study. The duration of the second stage of labour is shorter with Valsalva pushing but the clinical significance of this finding is uncertain. The primary studies are sparse, diverse and some flawed. Further research seems warranted. In the mean time supporting spontaneous pushing and encouraging women to choose their own method of pushing should be accepted as best clinical practice. © 2011 The Authors BJOG An

Effects of pushing techniques during the second stage of labor: A randomized controlled trial.

Science.gov (United States)

Koyucu, Refika Genç; Demirci, Nurdan

2017-10-01

Spontaneous pushing is a method that is used in the management of the second stage of labor and suggested to be more physiological for the mother and infant. The present study aims to evaluate the effects of pushing techniques on the mother and newborn. This randomized prospective study was performed between June 2013-March 2014 in a tertiary maternity clinic in Istanbul. 80 low risk, nulliparous cases were randomized to pushing groups. Valsalva pushing group was told to hold their breath while pushing. No visual-verbal instructions were given to spontaneous pushing group and they were encouraged to push without preventing respiration. Demographic data, second stage period, perineal laceration rates, fetal heart rate patterns, presence of meconium stained amniotic liquid, newborn APGAR scores, POP-Q examination and Q-tip test results were evaluated in these cases. The second stage of labor was significantly longer with spontaneous pushing. Decrease in Hb levels in valsalva pushing group was determined to be higher than spontaneous pushing group. An increased urethral mobility was observed in valsalva pushing group. Although the duration of the second stage of labor was longer compared to valsalva pushing technique, women were able to give birth without requiring any verbal or visual instruction, without exceeding the limit value of two hours and without affecting fetal wellness and neonatal results. Copyright © 2017. Published by Elsevier B.V.

Developing technology pushed breakthroughs: an empirical study

Directory of Open Access Journals (Sweden)

Jari Sarja

2017-12-01

Full Text Available Developing a technology push product that brings real novelty to the market is difficult, risky and costly. This case study analyzes success factors defined by the literature. True industrial cases, representing Finnish ICT firms in their early phase after a successful market entry, were researched for the success factor analysis. The whole set of the previously introduced success factors were variably supported, and three new factors arose. Because the technology pushed development processes are risky with high failure rates, the validated success factors are valuable knowledge for the developments intensive firm’s management.

Particle Engulfment and Pushing

Science.gov (United States)

2001-01-01

As a liquefied metal solidifies, particles dispersed in the liquid are either pushed ahead of or engulfed by the moving solidification front. Similar effects can be seen when the ground freezes and pushes large particles out of the soil. The Particle Engulfment and Pushing (PEP) experiment, conducted aboard the fourth U.S. Microgravity Payload (USMP-4) mission in 1997, used a glass and plastic beads suspended in a transparent liquid. The liquid was then frozen, trapping or pushing the particles as the solidifying front moved. This simulated the formation of advanced alloys and composite materials. Such studies help scientists to understand how to improve the processes for making advanced materials on Earth. The principal investigator is Dr. Doru Stefanescu of the University of Alabama. This image is from a video downlink.

External Hand Forces Exerted by Long-Term Care Staff to Push Floor-Based Lifts: Effects of Flooring System and Resident Weight.

Science.gov (United States)

Lachance, Chantelle C; Korall, Alexandra M B; Russell, Colin M; Feldman, Fabio; Robinovitch, Stephen N; Mackey, Dawn C

2016-09-01

The aim of this study was to investigate the effects of flooring type and resident weight on external hand forces required to push floor-based lifts in long-term care (LTC). Novel compliant flooring is designed to reduce fall-related injuries among LTC residents but may increase forces required for staff to perform pushing tasks. A motorized lift may offset the effect of flooring on push forces. Fourteen female LTC staff performed straight-line pushes with two floor-based lifts (conventional, motor driven) loaded with passengers of average and 90th-percentile resident weights over four flooring systems (concrete+vinyl, compliant+vinyl, concrete+carpet, compliant+carpet). Initial and sustained push forces were measured by a handlebar-mounted triaxial load cell and compared to participant-specific tolerance limits. Participants rated pushing difficulty. Novel compliant flooring increased initial and sustained push forces and subjective ratings compared to concrete flooring. Compared to the conventional lift, the motor-driven lift substantially reduced initial and sustained push forces and perceived difficulty of pushing for all four floors and both resident weights. Participants exerted forces above published tolerance limits only when using the conventional lift on the carpet conditions (concrete+carpet, compliant+carpet). With the motor-driven lift only, resident weight did not affect push forces. Novel compliant flooring increased linear push forces generated by LTC staff using floor-based lifts, but forces did not exceed tolerance limits when pushing over compliant+vinyl. The motor-driven lift substantially reduced push forces compared to the conventional lift. Results may help to address risk of work-related musculoskeletal injury, especially in locations with novel compliant flooring. © 2016, Human Factors and Ergonomics Society.

Octopus movement: push right, go left.

Science.gov (United States)

Hooper, Scott L

2015-05-04

Octopus arms have essentially infinite degrees of freedom. New research shows that, despite this potentially great complexity, to locomote octopuses simply elongate one or more arms, thus pushing the body in the opposite direction, and do so without activating the arms in an ordered pattern. Copyright © 2015 Elsevier Ltd. All rights reserved.

Psychophysically determined forces of dynamic pushing for female industrial workers: Comparison of two apparatuses.

Science.gov (United States)

Ciriello, Vincent M; Maikala, Rammohan V; Dempsey, Patrick G; O'Brien, Niall V

2010-01-01

Using psychophysics, the maximum acceptable forces for pushing have been previously developed using a magnetic particle brake (MPB) treadmill at the Liberty Mutual Research Institute for Safety. The objective of this study was to investigate the reproducibility of maximum acceptable initial and sustained forces while performing a pushing task at a frequency of 1min(-1) both on a MPB treadmill and on a high-inertia pushcart. This is important because our pushing guidelines are used extensively as a ergonomic redesign strategy and we would like the information to be as applicable as possible to cart pushing. On two separate days, nineteen female industrial workers performed a 40-min MPB treadmill pushing task and a 2-hr pushcart task, in the context of a larger experiment. During pushing, the subjects were asked to select a workload they could sustain for 8h without "straining themselves or without becoming unusually tired, weakened, overheated or out of breath." The results demonstrated that maximum acceptable initial and sustained forces of pushing determined on the high inertia pushcart were 0.8% and 2.5% lower than the MPB treadmill. The results also show that the maximum acceptable sustained force of the MPB treadmill task was 0.5% higher than the maximum acceptable sustained force of Snook and Ciriello (1991). Overall, the findings confirm that the existing pushing data developed by the Liberty Mutual Research Institute for Safety still provides an accurate estimate of maximal acceptable forces for the selected combination of distance and frequency of push for female industrial workers.

SA in nuclear power push

International Nuclear Information System (INIS)

Anon.

1982-01-01

Uranium research takes on a new lease of life as South Africa pushes ahead with a two-pronged attack on future energy needs. The recent allocation to the Department of Mineral and Energy Affairs of more than R106 million for atomic energy research indicates that South Africa's heavy commitment to nuclear spending involves not only the Koeberg power station, with its two pressurised water reactors, but also a uranium enrichment plant that is expected to be in commercial production by 1985. Other countries' expenditures on nuclear activities are also discussed

Effect of push handle height on net moments and forces on the musculoskeletal system during standardized wheelchair pushing tasks

NARCIS (Netherlands)

Van Der Woude, L H; Van Koningsbruggen, C M; Kroes, A L; Kingma, I

1995-01-01

The aim of this investigation was to analyze the external forces and biomechanical loading on the musculoskeletal system during wheelchair pushing, in relation to different push handle heights. In addition, recommendations for wheelchair pushing in accordance with push handle height are made. Eight

Push piece for spent fuel elements magazine

International Nuclear Information System (INIS)

Griveau, R.; Kerlau, D.; Tucoulat, D.; Colas, J.; Pellier, R.

1989-01-01

The push piece permits the displacement of little section elements in a magazine of high section. At the end of cut, the push piece leans its flank against an auxiliary blank holder and the element is pushed by a paddle, the push piece being immobilized [fr

To push or not to push? Affective influences on moral judgment depend on decision frame.

Science.gov (United States)

Pastötter, Bernhard; Gleixner, Sabine; Neuhauser, Theresa; Bäuml, Karl-Heinz T

2013-03-01

People's moods can influence moral judgment. Such influences may arise because moods affect moral emotion, or because moods affect moral thought. The present study provides evidence that, at least in the footbridge dilemma, moods affect moral thought. The results of two experiments are reported in which, after induction of positive, negative, or neutral moods and presentation of the footbridge scenario, participants were asked one of two differentially framed closing questions. In the active frame, participants were asked whether they would be active and push the man, making thoughts about pushing accessible; in the passive frame, they were asked whether they would be passive and not push the man, making thoughts about not pushing accessible. The results show that affective influences on moral judgment depended on participants' decision frame. Compared to neutral moods, positive moods induced utilitarian responding - i.e., deciding to push - in the active decision frame, but induced nonutilitarian responding - i.e., deciding to not push - in the passive decision frame; in negative moods, exactly the opposite picture arose. The results suggest that people's moods affect moral judgment by conferring value on moral thought. Positive moods promote and negative moods inhibit accessible thoughts. Copyright © 2012 Elsevier B.V. All rights reserved.

Incorporating pushing in exclusion-process models of cell migration.

Science.gov (United States)

Yates, Christian A; Parker, Andrew; Baker, Ruth E

2015-05-01

The macroscale movement behavior of a wide range of isolated migrating cells has been well characterized experimentally. Recently, attention has turned to understanding the behavior of cells in crowded environments. In such scenarios it is possible for cells to interact, inducing neighboring cells to move in order to make room for their own movements or progeny. Although the behavior of interacting cells has been modeled extensively through volume-exclusion processes, few models, thus far, have explicitly accounted for the ability of cells to actively displace each other in order to create space for themselves. In this work we consider both on- and off-lattice volume-exclusion position-jump processes in which cells are explicitly allowed to induce movements in their near neighbors in order to create space for themselves to move or proliferate into. We refer to this behavior as pushing. From these simple individual-level representations we derive continuum partial differential equations for the average occupancy of the domain. We find that, for limited amounts of pushing, comparison between the averaged individual-level simulations and the population-level model is nearly as good as in the scenario without pushing. Interestingly, we find that, in the on-lattice case, the diffusion coefficient of the population-level model is increased by pushing, whereas, for the particular off-lattice model that we investigate, the diffusion coefficient is reduced. We conclude, therefore, that it is important to consider carefully the appropriate individual-level model to use when representing complex cell-cell interactions such as pushing.

KOMPARASI SISTEM MANUFAKTUR PUSH DAN PULL MELALUI PENDEKATAN SIMULASI

Directory of Open Access Journals (Sweden)

Eric Wibisono

2004-01-01

Full Text Available Manufacturing systems that are often classified as push and pull often invite question: "How far do the differences between those two systems exist?" Many researches have been carried out but succinct answer to the above question is always difficult to reach. The difficulty roots from the variety of definition of the push and pull systems itself and also from the variety of complexity of a manufacturing system. This paper attempts to study the differences in performance between push and pull systems in a relatively simple model that consists of 4 serial processors with buffers located between these processors. Variations being modelled is on the setting of the system's load (high and low and the buffer size with performance being measured include machine utilization, number of outputs and mean flow time of jobs. The approach used is simulation using ProModel software as the tool. From the experiments it can be derived that buffer size turns out to be a very critical factor in system performance. Moreover, it is also proved that when the buffer size is large, push and pull systems do not differ significantly. Abstract in Bahasa Indonesia : Sistem manufaktur yang umumnya dikategorikan menjadi sistem push dan pull sering mengundang pertanyaan: "Seberapa jauh perbedaan dari kedua sistem tersebut ada?" Banyak penelitian telah dilakukan namun jawaban yang lugas atas pertanyaan tersebut sulit diperoleh. Kesulitan ini umumnya berakar dari beragamnya definisi sistem push dan pull itu sendiri serta variasi dari kompleksitas suatu sistem manufaktur. Makalah ini mencoba melihat perbedaan antara kinerja sistem push dan pull dalam suatu model sederhana yang terdiri dari 4 prosesor serial dengan buffer yang diletakkan di antara masing-masing prosesor tersebut. Variasi yang dilakukan adalah pada setting beban kerja sistem (padat dan ringan dan ukuran buffer dengan kinerja yang diukur adalah utilisasi mesin, jumlah output dan rata-rata waktu tinggal job

Scapular kinematics and muscle activities during pushing tasks.

Science.gov (United States)

Huang, Chun-Kai; Siu, Ka-Chun; Lien, Hen-Yu; Lee, Yun-Ju; Lin, Yang-Hua

2013-01-01

Pushing tasks are functional activities of daily living. However, shoulder complaints exist among workers exposed to regular pushing conditions. It is crucial to investigate the control of shoulder girdles during pushing tasks. The objective of the study was to demonstrate scapular muscle activities and motions on the dominant side during pushing tasks and the relationship between scapular kinematics and muscle activities in different pushing conditions. Thirty healthy adults were recruited to push a four-wheel cart in six pushing conditions. The electromyographic signals of the upper trapezius (UT) and serratus anterior (SA) muscles were recorded. A video-based system was used for measuring the movement of the shoulder girdle and scapular kinematics. Differences in scapular kinematics and muscle activities due to the effects of handle heights and weights of the cart were analyzed using two-way ANOVA with repeated measures. The relationships between scapular kinematics and muscle activities were examined by Pearson's correlation coefficients. The changes in upper trapezius and serratus anterior muscle activities increased significantly with increased pushing weights in the one-step pushing phase. The UT/SA ratio on the dominant side decreases significantly with increased handle heights in the one-step pushing phase. The changes in upward rotation, lateral slide and elevation of the scapula decreased with increased pushing loads in the trunk-forward pushing phase. This study indicated that increased pushing loads result in decreased motions of upward rotation, lateral slide and elevation of the scapula; decreased handle heights result in relatively increased activities of the serratus anterior muscles during pushing tasks.

Boris push with spatial stepping

International Nuclear Information System (INIS)

Penn, G; Stoltz, P H; Cary, J R; Wurtele, J

2003-01-01

The Boris push is commonly used in plasma physics simulations because of its speed and stability. It is second-order accurate, requires only one field evaluation per time step, and has good conservation properties. However, for accelerator simulations it is convenient to propagate particles in z down a changing beamline. A 'spatial Boris push' algorithm has been developed which is similar to the Boris push but uses a spatial coordinate as the independent variable, instead of time. This scheme is compared to the fourth-order Runge-Kutta algorithm, for two simplified muon beam lattices: a uniform solenoid field, and a 'FOFO' lattice where the solenoid field varies sinusoidally along the axis. Examination of the canonical angular momentum, which should be conserved in axisymmetric systems, shows that the spatial Boris push improves accuracy over long distances

Pushing/bearing down methods for the second stage of labour.

Science.gov (United States)

Lemos, Andrea; Amorim, Melania Mr; Dornelas de Andrade, Armele; de Souza, Ariani I; Cabral Filho, José Eulálio; Correia, Jailson B

2017-03-26

Maternal pushing during the second stage of labour is an important and indispensable contributor to the involuntary expulsive force developed by uterine contraction. There is no consensus on an ideal strategy to facilitate these expulsive efforts and there are contradictory results about the influence on the mother and fetus. To evaluate the benefits and possible disadvantages of different kinds of techniques regarding maternal pushing/breathing during the expulsive stage of labour on maternal and fetal outcomes. We searched Cochrane Pregnancy and Childbirth's Trials Register (19 September 2016) and reference lists of retrieved studies. Randomised controlled trials (RCTs) and quasi-RCTs assessing the effects of pushing/bearing down techniques (type and/or timing) performed during the second stage of labour on maternal and neonatal outcomes. Cluster-RCTs were eligible for inclusion, but none were identified. Studies using a cross-over design and those published in abstract form only were not eligible for inclusion in this review. Two review authors independently assessed trials for inclusion, extracted data and assessed risk of bias. Data were checked for accuracy. In this updated review, we included 21 studies in total, eight (884 women) comparing spontaneous pushing versus directed pushing, with or without epidural analgesia and 13 (2879 women) comparing delayed pushing versus immediate pushing with epidural analgesia. Our GRADE assessments of evidence ranged from moderate to very low quality; the main reasons for downgrading were study design limitations and imprecision of effect estimates. Overall, the included studies varied in their risk of bias; most were judged to be at unclear risk of bias. Comparison 1: types of pushing: spontaneous pushing versus directed pushingThere was no clear difference in the duration of the second stage of labour (mean difference (MD) 10.26 minutes; 95% confidence interval (CI) -1.12 to 21.64 minutes, six studies, 667 women, random

Foot placement strategy in pushing and pulling.

Science.gov (United States)

Lee, Tzu-Hsien

2018-01-01

Pushing and pulling tasks are very common in daily and industrial workplaces. They are one major source of musculoskeletal complaints. This study aimed to examine the foot placement strategy while pushing and pulling. Thirteen young males and ten young females were recruited as participants. A two (pushing and pulling) by four (48 cm, 84 cm, 120 cm, and 156 cm) factorial design was used. Exertion direction and exertion height significantly affected foot placement strategy. Pushing task needed more anteroposterior space than pulling task. The percentages of female/male for trailing foot position ranged from 77% to 90% (pushing) and from 80% to 93% (pulling) across the exertion heights. Practitioners should provide an anteroposterior space approximately to 70% body stature for workers to exert their maximum pulling and pushing strengths.

Proc. of the workshop on pushing the limits of RF superconductivity.

Energy Technology Data Exchange (ETDEWEB)

Kim, K-J., Eyberger, C., editors

2005-04-13

For three days in late September last year, some sixty experts in RF superconductivity from around the world came together at Argonne to discuss how to push the limits of RF superconductivity for particle accelerators. It was an intense workshop with in-depth presentations and ample discussions. There was added excitement due to the fact that, a few days before the workshop, the International Technology Recommendation Panel had decided in favor of superconducting technology for the International Linear Collider (ILC), the next major high-energy physics accelerator project. Superconducting RF technology is also important for other large accelerator projects that are either imminent or under active discussion at this time, such as the Rare Isotope Accelerator (RIA) for nuclear physics, energy recovery linacs (ERLs), and x-ray free-electron lasers. For these accelerators, the capability in maximum accelerating gradient and/or the Q value is essential to limit the length and/or operating cost of the accelerators. The technological progress of superconducting accelerators during the past two decades has been truly remarkable, both in low-frequency structures for acceleration of protons and ions as well as in high-frequency structures for electrons. The requirements of future accelerators demand an even higher level of performance. The topics of this workshop are therefore highly relevant and timely. The presentations given at the workshop contained authoritative reviews of the current state of the art as well as some original materials that previously had not been widely circulated. We therefore felt strongly that these materials should be put together in the form of a workshop proceeding. The outcome is this report, which consists of two parts: first, a collection of the scholarly papers prepared by some of the participants and second, copies of the viewgraphs of all presentations. The presentation viewgraphs, in full color, are also available from the Workshop

Push-pull alkenes: structure and p-electron distribution

Directory of Open Access Journals (Sweden)

ERICH KLEINPETER

2006-01-01

Full Text Available Push-pull alkenes are substituted alkenes with one or two electron-donating substituents on one end of C=C double bond and with one or two electron-accepting substituents at the other end. Allowance for p-electron delocalization leads to the central C=C double bond becoming ever more polarized and with rising push-pull character, the p-bond order of this double bond is reduced and, conversely, the corresponding p-bond orders of the C–Don and C–Acc bonds are accordingly increased. This push-pull effect is of decisive influence on both the dynamic behavior and the chemical reactivity of this class of compounds and thus it is of considerable interest to both determine and to quantify the inherent push-pull effect. Previously, the barriers to rotation about the C=C, C–Don and/or C–Acc partial double bonds (DG±, as determined by dynamic NMR spectroscopy or the 13C chemical shift difference of the polarized C=C partial double bond (DdC=C were employed for this purpose. However, these parameters can have serious limitations, viz. the barriers can be immeasurable on the NMR timescale (either by being too high or too low; heavily-biased conformers are present, etc. or DdC=C behaves in a non-additive manner with respect to the combination of the four substituents. Hence, a general parameter to quantify the push-pull effect is not yet available. Ab initio MO calculations on a collection of compounds, together with NBO analysis, provided valuable information on the structure, bond energies, electron occupancies and bonding/antibonding interactions. In addition to DG±C=C (either experimentally determined or theoretically calculated and DdC=C, the bond length of the C=C partial double bond was also examined and it proved to be a reliable parameter to quantify the push-pull effect. Equally so, the quotient of the occupation numbers of the antibonding andbonding p orbitals of the central C=C partial double bond ( p*C=C/ pC=C could also be employed for

Outer Limits of Biotechnologies: A Jewish Perspective

Directory of Open Access Journals (Sweden)

John D. Loike

2018-01-01

Full Text Available A great deal of biomedical research focuses on new biotechnologies such as gene editing, stem cell biology, and reproductive medicine, which have created a scientific revolution. While the potential medical benefits of this research may be far-reaching, ethical issues related to non-medical applications of these technologies are demanding. We analyze, from a Jewish legal perspective, some of the ethical conundrums that society faces in pushing the outer limits in researching these new biotechnologies.

Healthy Birth Practice #5: Avoid Giving Birth on Your Back and Follow Your Body's Urge to Push.

Science.gov (United States)

DiFranco, Joyce T; Curl, Marilyn

2014-01-01

Women in the United States are still giving birth in the supine position and are restricted in how long they can push and encouraged to push forcefully by their caregivers. Research does not support these activities. There is discussion about current research and suggestions on how to improve the quality of the birth experience. This article is an updated evidence-based review of the "Lamaze International Care Practices That Promote Normal Birth, Care Practice #5: Spontaneous Pushing in Upright or Gravity-Neutral Positions," published in The Journal of Perinatal Education, 16(3), 2007.

Two-Man Bobsled Push Start Analysis

Directory of Open Access Journals (Sweden)

Lopes Alexandre Dias

2016-04-01

Full Text Available The importance of push start times on bobsled performance was evidenced by some studies, but at this moment there is no article to the authors’ knowledge that describes the bobsled push start. Thus, the objectives of this study were to describe the two-man bobsled push start, analyze the differences between teams, and estimate the most important variable analyzed. We hypothesized that the pilot and brakeman athletes’ movement patterns during a bobsled pushing start can be described. The images used in this study were obtained during the men’s two-man XIV World Championship of Bobsled (2004. Fifteen best teams participating in the championship were recorded, and four start runs for each team were analyzed. The videos were captured by two digital video cameras. The pilot athletes were analyzed during the moment that they touched the lateral push bar of the sled, and the brakemen were analyzed during the first take-off and first landing. The teams were pooled in three groups of five teams using the final ranking of pushing time. We concluded that there was a distinct pattern movement for pilots and brakemen. The initial position of the majority of the pilots was localized slightly behind the bar. After touching the lateral bar, the pilots remained in a semi-squat position, pushing the sled forward in a pattern of marching movement. All brakemen used the board attached to the track as a support for both feet at the start. The brakeman gave the greatest contribution to break the inertia of the sled. There was no significant difference of movement between the three groups analyzed for the pilot and the brakeman.

Effect of a powered drive on pushing and pulling forces when transporting bariatric hospital beds.

Science.gov (United States)

Wiggermann, Neal

2017-01-01

Powered drives designed to assist with moving hospital beds are commercially available but no studies have evaluated whether they reduce the push and pull forces likely contributing to injury in caregivers. This study measured hand forces of 10 caregivers maneuvering a manual and powered bariatric bed through simulated hospital environments (hallway, elevator, and ramp). Peak push and pull forces exceeded previously established psychophysical limits for all activities with the manual bed. For the powered bed, peak forces were significantly (p pushing did not differ between beds. Powered drive may reduce the risk of injury or the number of caregivers needed for transport. Copyright © 2016 Elsevier Ltd. All rights reserved.

'Mister Badger' Pushing Mars Rock

Science.gov (United States)

1976-01-01

Viking's soil sampler collector arm successfully pushed a rock on the surface of Mars during the afternoon of Friday, October 8. The irregular-shaped rock was pushed several inches by the Lander's collector arm, which displaced the rock to the left of its original position, leaving it cocked slightly upward. Photographs and other information verified the successful rock push. Photo at left shows the soil sampler's collector head pushing against the rock, named 'Mister Badger' by flight controllers. Photo at right shows the displaced rock and the depression whence it came. Part of the soil displacement was caused by the collector s backhoe. A soil sample will be taken from the site Monday night, October 11. It will then be delivered to Viking s organic chemistry instrument for a series of analyses during the next few weeks. The sample is being sought from beneath a rock because scientists believe that, if there are life forms on Mars, they may seek rocks as shelter from the Sun s intense ultraviolet radiation.

Delayed versus immediate pushing in second stage of labor.

Science.gov (United States)

Kelly, Mary; Johnson, Eileen; Lee, Vickie; Massey, Liz; Purser, Debbie; Ring, Karen; Sanderson, Stephanye; Styles, Juanita; Wood, Deb

2010-01-01

Comparison of two different methods for management of second stage of labor: immediate pushing at complete cervical dilation of 10 cm and delayed pushing 90 minutes after complete cervical dilation. This study was a randomized clinical trial in a labor and delivery unit of a not-for-profit community hospital. A sample of 44 nulliparous mothers with continuous epidural anesthesia were studied after random assignment to treatment groups. Subjects were managed with either immediate or delayed pushing during the second stage of labor at the time cervical dilation was complete. The primary outcome measure was the length of pushing during second stage of labor. Secondary outcomes included length of second stage of labor, maternal fatigue and perineal injuries, and fetal heart rate decelerations. Two-tailed, unpaired Student's t-tests and Chi-square analysis were used for data analysis. Level of significance was set at p pushing; N = 16 delayed pushing). The delayed pushing group had significantly shorter amount of time spent in pushing compared with the immediate pushing group (38.9 +/- 6.9 vs. 78.7 +/- 7.9 minutes, respectively, p = .002). Maternal fatigue scores, perineal injuries, and fetal heart rate decelerations were similar for both groups. Delaying pushing for up to 90 minutes after complete cervical dilation resulted in a significant decrease in the time mothers spent pushing without a significant increase in total time in second stage of labor.In clinical practice, healthcare providers sometimes resist delaying the onset of pushing after second stage of labor has begun because of a belief it will increase labor time. This study's finding of a 51% reduction in pushing time when mothers delay pushing for up to 90 minutes, with no significant increase in overall time for second stage of labor, disputes that concern.

Pushing and pulling: an assessment tool for occupational health and safety practitioners.

Science.gov (United States)

Lind, Carl Mikael

2018-03-01

A tool has been developed for supporting practitioners when assessing manual pushing and pulling operations based on an initiative by two global companies in the manufacturing industry. The aim of the tool is to support occupational health and safety practitioners in risk assessment and risk management of pushing and pulling operations in the manufacturing and logistics industries. The tool is based on a nine-multiplier equation that includes a wide range of factors affecting an operator's health risk and capacity in pushing and pulling. These multipliers are based on psychophysical, physiological and biomechanical studies in combination with judgments from an expert group consisting of senior researchers and ergonomists. In order to consider usability, more than 50 occupational health and safety practitioners (e.g., ergonomists, managers, safety representatives and production personnel) participated in the development of the tool. An evaluation by 22 ergonomists supports that the push/pull tool is user friendly in general.

Optimization of ramp area aircraft push back time windows in the presence of uncertainty

Science.gov (United States)

Coupe, William Jeremy

It is well known that airport surface traffic congestion at major airports is responsible for increased taxi-out times, fuel burn and excess emissions and there is potential to mitigate these negative consequences through optimizing airport surface traffic operations. Due to a highly congested voice communication channel between pilots and air traffic controllers and a data communication channel that is used only for limited functions, one of the most viable near-term strategies for improvement of the surface traffic is issuing a push back advisory to each departing aircraft. This dissertation focuses on the optimization of a push back time window for each departing aircraft. The optimization takes into account both spatial and temporal uncertainties of ramp area aircraft trajectories. The uncertainties are described by a stochastic kinematic model of aircraft trajectories, which is used to infer distributions of combinations of push back times that lead to conflict among trajectories from different gates. The model is validated and the distributions are included in the push back time window optimization. Under the assumption of a fixed taxiway spot schedule, the computed push back time windows can be integrated with a higher level taxiway scheduler to optimize the flow of traffic from the gate to the departure runway queue. To enable real-time decision making the computational time of the push back time window optimization is critical and is analyzed throughout.

Import-push or Export-pull?

DEFF Research Database (Denmark)

Jäkel, Ina Charlotte

2014-01-01

predictions regarding the export market and the role of product differentiation. Empirical results for a sample of Danish manufacturing industries confirm the import- "push" hypothesis as well as the export- "pull" hypothesis, but also reveal differences across industries. The selection effect of trade...... is mainly driven by the "import-push" if product differentiation is high, whereas it is driven by the "export-pull" if goods are homogeneous....

Import-push or Export-pull?

DEFF Research Database (Denmark)

Jäkel, Ina Charlotte

predictions regarding the export market and the role of product differentiation. Empirical results for a sample of Danish manufacturing industries confirm the import-"push" hypothesis as well as the export-"pull" hypothesis, but also reveal differences across industries. The selection effect of trade...... is mainly driven by the "import-push" if product differentiation is high, whereas it is driven by the "export-pull" if goods are homogeneous....

Kinematics of the field hockey penalty corner push-in.

Science.gov (United States)

Kerr, Rebecca; Ness, Kevin

2006-01-01

The aims of the study were to determine those variables that significantly affect push-in execution and thereby formulate coaching recommendations specific to the push-in. Two 50 Hz video cameras recorded transverse and longitudinal views of push-in trials performed by eight experienced and nine inexperienced male push-in performers. Video footage was digitized for data analysis of ball speed, stance width, drag distance, drag time, drag speed, centre of massy displacement and segment and stick displacements and velocities. Experienced push-in performers demonstrated a significantly greater (p push-in and a significantly faster ball speed than inexperienced performers. In addition, the experienced performers showed a significant positive correlation between ball speed and playing experience and tended to adopt a combination of simultaneous and sequential segment rotation to achieve accuracy and fast ball speed. The study yielded the following coaching recommendations for enhanced push-in performance: maximize drag distance by maximizing front foot-ball distance at the start of the push-in; use a combination of simultaneous and sequential segment rotations to optimise both accuracy and ball speed and maximize drag speed.

33 CFR 83.24 - Towing and pushing (Rule 24).

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Towing and pushing (Rule 24). 83... NAVIGATION RULES RULES Lights and Shapes § 83.24 Towing and pushing (Rule 24). (a) A power-driven vessel when... it can best be seen. (b) Pushing vessel and pushed vessel rigidly connected in composite unit. When a...

Impulsive ankle push-off powers leg swing in human walking.

Science.gov (United States)

Lipfert, Susanne W; Günther, Michael; Renjewski, Daniel; Seyfarth, Andre

2014-04-15

Rapid unloading and a peak in power output of the ankle joint have been widely observed during push-off in human walking. Model-based studies hypothesize that this push-off causes redirection of the body center of mass just before touch-down of the leading leg. Other research suggests that work done by the ankle extensors provides kinetic energy for the initiation of swing. Also, muscle work is suggested to power a catapult-like action in late stance of human walking. However, there is a lack of knowledge about the biomechanical process leading to this widely observed high power output of the ankle extensors. In our study, we use kinematic and dynamic data of human walking collected at speeds between 0.5 and 2.5 m s(-1) for a comprehensive analysis of push-off mechanics. We identify two distinct phases, which divide the push-off: first, starting with positive ankle power output, an alleviation phase, where the trailing leg is alleviated from supporting the body mass, and second, a launching phase, where stored energy in the ankle joint is released. Our results show a release of just a small part of the energy stored in the ankle joint during the alleviation phase. A larger impulse for the trailing leg than for the remaining body is observed during the launching phase. Here, the buckling knee joint inhibits transfer of power from the ankle to the remaining body. It appears that swing initiation profits from an impulsive ankle push-off resulting from a catapult without escapement.

Fuzzy Based PC-PUSH in CR-MANETs

Directory of Open Access Journals (Sweden)

S. Nejatian

2014-01-01

Full Text Available In cognitive radio (CR, the secondary user (SU needs to hand off its ongoing communication to an idle channel in order to avoid interference to the primary user (PU. Spectrum hand off issue becomes challenging in CR mobile ad hoc networks (CR-MANETs because of the uncertainty in spectrum availability, broad range of spectrum bands and lack of central entity. The purpose of this study is to design a unified spectrum handoff (USH scheme for CR-MANETs that considers the spectrum heterogeneity and its availability over time and space. A local flow hand off is performed when spectrum hand off cannot be carried out due to the SUs mobility. To improve further USH, preemptive unified spectrum handoff (PUSH algorithm is proposed in which two different preemptive hand off threshold regions are defined. The PUSH algorithm also predicts the cognitive link availability considering the PU interference boundary. Although the PUSH scheme improves the hand off performance, the number of spectrum hand offs due to the PU activity should be reduced in this scheme. Therefore, the PC-PUSH (Power Controller-PUSH scheme is proposed in which the fuzzy logic is used to improve the PUSH in terms of the number of spectrum handoffs because of the PU activity. The PC-PUSH decreases the interference to the PUs, while reducing the number of spectrum handoffs. The results show that the proposed scheme improves the link maintenance probability, decreases the hand off delay, and reduces the number of spectrum handoffs.

Limits to magnetic resonance microscopy

International Nuclear Information System (INIS)

Glover, Paul; Mansfield, Peter

2002-01-01

The last quarter of the twentieth century saw the development of magnetic resonance imaging (MRI) grow from a laboratory demonstration to a multi-billion dollar worldwide industry. There is a clinical body scanner in almost every hospital of the developed nations. The field of magnetic resonance microscopy (MRM), after mostly being abandoned by researchers in the first decade of MRI, has become an established branch of the science. This paper reviews the development of MRM over the last decade with an emphasis on the current state of the art. The fundamental principles of imaging and signal detection are examined to determine the physical principles which limit the available resolution. The limits are discussed with reference to liquid, solid and gas phase microscopy. In each area, the novel approaches employed by researchers to push back the limits of resolution are discussed. Although the limits to resolution are well known, the developments and applications of MRM have not reached their limit. (author)

49 CFR 218.99 - Shoving or pushing movements.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Shoving or pushing movements. 218.99 Section 218... Derails § 218.99 Shoving or pushing movements. (a)(1) Each railroad shall adopt and comply with an... violated the requirements of this section. (2) The following requirements for shoving or pushing movements...

Effect of push frequency on the economy of wheelchair racers.

Science.gov (United States)

Goosey, V L; Campbell, I G; Fowler, N E

2000-01-01

The aim of the study was to examine the effect of varying push frequency on pushing economy (oxygen uptake at a given speed). Eight male wheelchair racers completed a series of exercise bouts on a wheelchair ergometer (Bromking Turbo Trainer, Bromakin, UK) at 6.58 m x s(-1). Initially, subjects self-selected their freely chosen push frequency (FCF); this was followed by 4 random trials pushing at 60, 80, 120, and 140% of this FCF. Steady state VO2 was determined using Douglas bags, and heart rate was recorded by telemetry. After each condition, a small capillary blood sample was obtained and analyzed for blood lactate concentration (BLa) and a rating of perceived exertion (RPE) was recorded. At 6.58 m x s(-1) oxygen uptake, RPE, and gross mechanical efficiency were nonlinearly related to push frequency. Analysis of variance showed a significant effect (P push frequency had little effect on HR although BLa increased linearly and was higher at the 140% FCF condition compared with 60% FCF (P push frequency increased. The start angle and end angle of hand contact were similar for conditions, whereas the range of trunk motion decreased with push frequency (P push frequency had an effect on pushing economy, and that the athletes' FCF was the most economical.

Deep groundwater flow systems and their characterization in single-well settings by ''push-pull'' tracer tests

International Nuclear Information System (INIS)

Hebig-Schubert, Klaus

2014-01-01

This thesis demonstrates the growing importance of deep groundwater research and the increasing demand for the development of suitable single-well test methods. At the forefront of the research on groundwater in the deep underground, radioactive waste disposal in deep geological repositories, CO 2 storage, geothermal energy supply, and aquifer storage and recovery systems (ASR) are on the agenda. The developments of suitable methods for investigating these resources are a main target. Currently available methods show considerable limitations. Accordingly, comprehensive methods for the hydraulic and hydrochemical characterization of deeper aquifers with single-well access are needed. Therefore, the goal of this PhD thesis was to identify, test, and enhance potentially suitable single-well methods for characterization of groundwater flow and solute transport in such settings. For this, several Single-Well Injection-Withdrawal (''push-pull'') tracer tests were applied at the Hamasato field site (Horonobe, Japan) in a ∝100 m deep groundwater monitoring well. Aim was to characterize the impact of a dynamic saltwater-freshwater interface on a coastal aquifer. Based on the experiences of the first methodological test, a second field campaign was conducted. This campaign focused on a systematic evaluation of the push-pull tracer test method for the first time at all. The experiments focused on the investigation of the so-called ''chaser'' and its impact on the test results. The chaser is a specific part of many push-pull tracer tests setups. From these experiments, a specific test design for the investigation of the saltwater-freshwater interface in a single-well setting was developed. The application of this design on questions regarding different fluids within the same system, e.g. different mineralized fluids (saltwater-freshwater-interface, ASR) or temperatures (geothermal research), are promising future approaches for this

Deep groundwater flow systems and their characterization in single-well settings by ''push-pull'' tracer tests

Energy Technology Data Exchange (ETDEWEB)

Hebig-Schubert, Klaus

2014-11-21

This thesis demonstrates the growing importance of deep groundwater research and the increasing demand for the development of suitable single-well test methods. At the forefront of the research on groundwater in the deep underground, radioactive waste disposal in deep geological repositories, CO{sub 2} storage, geothermal energy supply, and aquifer storage and recovery systems (ASR) are on the agenda. The developments of suitable methods for investigating these resources are a main target. Currently available methods show considerable limitations. Accordingly, comprehensive methods for the hydraulic and hydrochemical characterization of deeper aquifers with single-well access are needed. Therefore, the goal of this PhD thesis was to identify, test, and enhance potentially suitable single-well methods for characterization of groundwater flow and solute transport in such settings. For this, several Single-Well Injection-Withdrawal (''push-pull'') tracer tests were applied at the Hamasato field site (Horonobe, Japan) in a ∝100 m deep groundwater monitoring well. Aim was to characterize the impact of a dynamic saltwater-freshwater interface on a coastal aquifer. Based on the experiences of the first methodological test, a second field campaign was conducted. This campaign focused on a systematic evaluation of the push-pull tracer test method for the first time at all. The experiments focused on the investigation of the so-called ''chaser'' and its impact on the test results. The chaser is a specific part of many push-pull tracer tests setups. From these experiments, a specific test design for the investigation of the saltwater-freshwater interface in a single-well setting was developed. The application of this design on questions regarding different fluids within the same system, e.g. different mineralized fluids (saltwater-freshwater-interface, ASR) or temperatures (geothermal research), are promising future approaches for

PUSH-ing Construction Communications & Going Viral for Safety

OpenAIRE

Prevost, Dan; McCall, Bill

2018-01-01

Over the past 2 years, the Indiana Toll Road Concession Co. (ITRCC) and its contractors have delivered the 80/90 PUSH project, an ambitious rehabilitation of 70 miles of the Indiana Toll Road. The team developed an aggressive communications program to keep its customers and community stakeholders informed, partnering with the Indiana Motor Truck Association to take its Put the Phone Down campaign to social media. Join us for a discussion.

An Analysis of the Effects of Smartphone Push Notifications on Task Performance with regard to Smartphone Overuse Using ERP.

Science.gov (United States)

Kim, Seul-Kee; Kim, So-Yeong; Kang, Hang-Bong

2016-01-01

Smartphones are used ubiquitously worldwide and are essential tools in modern society. However, smartphone overuse is an emerging social issue, and limited studies have objectively assessed this matter. The majority of previous studies have included surveys or behavioral observation studies. Since a previous study demonstrated an association between increased push notifications and smartphone overuse, we investigated the effects of push notifications on task performance. We detected changes in brainwaves generated by smartphone push notifications using the N200 and P300 components of event-related potential (ERP) to investigate both concentration and cognitive ability. ERP assessment indicated that, in both risk and nonrisk groups, the lowest N200 amplitude and the longest latency during task performance were found when push notifications were delivered. Compared to the nonrisk group, the risk group demonstrated lower P300 amplitudes and longer latencies. In addition, the risk group featured a higher rate of error in the Go-Nogo task, due to the negative influence of smartphone push notifications on performance in both risk and nonrisk groups. Furthermore, push notifications affected subsequent performance in the risk group.

Contribution of limb momentum to power transfer in athletic wheelchair pushing.

Science.gov (United States)

Masson, G; Bégin, M-A; Lopez Poncelas, M; Pelletier, S-K; Lessard, J-L; Laroche, J; Berrigan, F; Langelier, E; Smeesters, C; Rancourt, D

2016-09-06

Pushing capacity is a key parameter in athletic racing wheelchair performance. This study estimated the potential contribution of upper limb momentum to pushing. The question is relevant since it may affect the training strategy adopted by an athlete. A muscle-free Lagrangian dynamic model of the upper limb segments was developed and theoretical predictions of power transfer to the wheelchair were computed during the push phase. Results show that limb momentum capacity for pushing can be in the order of 40J per push cycle at 10m/s, but it varies with the specific pushing range chosen by the athlete. Although use of momentum could certainly help an athlete improve performance, quantifying the actual contribution of limb momentum to pushing is not trivial. A preliminary experimental investigation on an ergometer, along with a simplified model of the upper limb, suggests that momentum is not the sole contributor to power transfer to a wheelchair. Muscles substantially contribute to pushing, even at high speeds. Moreover, an optimal pushing range is challenging to find since it most likely differs if an athlete chooses a limb momentum pushing strategy versus a muscular exertion pushing strategy, or both at the same time. The study emphasizes the importance of controlling pushing range, although one should optimize it while also taking the dynamics of the recovery period into account. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of prosthetic foot push-off on mechanical loading associated with knee osteoarthritis in lower extremity amputees.

Science.gov (United States)

Morgenroth, David C; Segal, Ava D; Zelik, Karl E; Czerniecki, Joseph M; Klute, Glenn K; Adamczyk, Peter G; Orendurff, Michael S; Hahn, Michael E; Collins, Steven H; Kuo, Art D

2011-10-01

Lower extremity amputation not only limits mobility, but also increases the risk of knee osteoarthritis of the intact limb. Dynamic walking models of non-amputees suggest that pushing-off from the trailing limb can reduce collision forces on the leading limb. These collision forces may determine the peak knee external adduction moment (EAM), which has been linked to the development of knee OA in the general population. We therefore hypothesized that greater prosthetic push-off would lead to reduced loading and knee EAM of the intact limb in unilateral transtibial amputees. Seven unilateral transtibial amputees were studied during gait under three prosthetic foot conditions that were intended to vary push-off. Prosthetic foot-ankle push-off work, intact limb knee EAM and ground reaction impulses for both limbs during step-to-step transition were measured. Overall, trailing limb prosthetic push-off work was negatively correlated with leading intact limb 1st peak knee EAM (slope=-.72±.22; p=.011). Prosthetic push-off work and 1st peak intact knee EAM varied significantly with foot type. The prosthetic foot condition with the least push-off demonstrated the largest knee EAM, which was reduced by 26% with the prosthetic foot producing the most push-off. Trailing prosthetic limb push-off impulse was negatively correlated with leading intact limb loading impulse (slope=-.34±.14; p=.001), which may help explain how prosthetic limb push-off can affect intact limb loading. Prosthetic feet that perform more prosthetic push-off appear to be associated with a reduction in 1st peak intact knee EAM, and their use could potentially reduce the risk and burden of knee osteoarthritis in this population. Published by Elsevier B.V.

[Development of Biliary Contrast Agents Remote Pushing Device].

Science.gov (United States)

Zhu, Haoyang; Dong, Dinghui; Luo, Yu; Ren, Fenggang; Zhang, Jing; Tan, Wenjun; Shi, Aihua; Hu, Liangshuo; Wu, Rongqian; Lyu, Yi

2018-01-30

A biliary contrast agents pushing device, including a syringe pushing system and a remote controller is introduced. The syringe pushing system comprises an injector card slot, a support platform and an injection bolus fader. A 20 mL syringe can be fitted on the syringe pushing system and kept with the ground about 30 degree. This system can perform air bubble pumping back and contrast agents bolus injection as well as speed adjustment. Remote controller is an infrared remote control which can start and stop the syringe pushing system. With this device, the remote controlled cholangiography technology can be achieved, which can not only protect doctors from X-ray radiation but also improve the traditional T-tube cholangiography and the contrast effect, reduce postoperative complications in patients as well. The application of this device will improve the current diagnosis and treatment system, the device will benefit the majority of doctors and patients.

Waste compatibility safety issues and final results for tank 241-T-110 push mode samples

International Nuclear Information System (INIS)

Nuzum, J.L.

1997-01-01

This document is the final laboratory report for Tank 241-T-110. Push mode core segments were removed from risers 2 and 6 between January 29, 1997, and February 7, 1997. Segments were received and extruded at 222-S Laboratory. Analyses were performed in accordance with Tank 241-T-110 Push Mode Core Sampling and analysis Plan (TSAP) and Safety Screening Data Quality Objective (DQO). None of the subsamples submitted for total alpha activity (AT) or differential scanning calorimetry (DSC) analyses exceeded the notification limits stated in DQO

Ground reaction force characteristics of Tai Chi push hand.

Science.gov (United States)

Chang, Yao-Ting; Chang, Jia-Hao; Huang, Chen-Fu

2014-01-01

Push Hand is an advanced training technique for the Yang-style old frame 108 forms Tai Chi Chuan. It is performed by two practitioners. To clarify how people use forces during Push Hand training, it is important to review the ground reaction force (GRF). Here, we quantify the characteristics of the GRF during Push Hand training. Kinematic data and GRF data from 10 Tai Chi Chuan practitioners (29.9 ± 7.87 years) were synchronously recorded using a three-dimensional motion analysis system (200 frames · s(-1)) and three-dimensional force plates (1000 Hz). The resultant GRF for both feet for the 0%, 50% and 100% phases of attack and defence were compared to body weight using a paired-samples t-test. The differences in the resultant GRF between the 0%, 50% and 100% phases of attack and defence were tested by one-way repeated-measures ANOVA. The significance level was set to 0.05. The total resultant GRF was almost equal to the participant's body weight in push hand. This result was consistent throughout the entire push hand process. Our results revealed that the GRF was comparable to the body weight, implying that practitioners do not push or resist their opponents during the push hand process.

Prone positioning reduces severe pushing behavior: three case studies.

Science.gov (United States)

Fujino, Yuji; Amimoto, Kazu; Sugimoto, Satoshi; Fukata, Kazuhiro; Inoue, Masahide; Takahashi, Hidetoshi; Makita, Shigeru

2016-09-01

[Purpose] Pushing behavior is classically described as a disorder of body orientation in the coronal plane. Most interventions for pushing behavior have focused on correcting the deviation in vertical perception. However, pushing behavior seems to involve erroneous movements associated with excessive motor output by the non-paretic limbs and trunk. The present study aimed to inhibit muscular hyper-activity by placing the non-paretic limbs and trunk in the prone position. [Subjects and Methods] The subjects of the present study were 3 acute stroke patients with severe pushing behavior. The study consisted of the following 3 phases: baseline, intervention, and follow-up. In addition to conventional therapy, patients received relaxation therapy in the prone position for 10 minutes a day over 2 days. The severity of pushing behavior was assessed using the scale for contraversive pushing, and truncal balance was evaluated using the trunk control test. These assessments were performed before and after the baseline phase, and after the intervention and follow-up phases. [Results] At the baseline phase, both scores were poor. Both scores improved after the intervention and follow-up phases, and all the patients could sit independently. [Conclusion] Relaxation therapy in the prone position might ameliorate pushing behavior and impaired truncal balance.

49 CFR 392.63 - Towing or pushing loaded buses.

Science.gov (United States)

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Towing or pushing loaded buses. 392.63 Section 392... COMMERCIAL MOTOR VEHICLES Prohibited Practices § 392.63 Towing or pushing loaded buses. No disabled bus with... passengers aboard for the purpose of towing or pushing any disabled motor vehicle, except in such...

Pushing the limits of NAA. Accuracy, uncertainty and detection limits

International Nuclear Information System (INIS)

Greenberg, R.R.

2008-01-01

This paper describes some highlights from the author's efforts to improve neutron activation analysis (NAA) detection limits through development and optimization of radiochemical separations, as well as to improve the overall accuracy of NAA measurements by identifying, quantifying and reducing measurement biases and uncertainties. Efforts to demonstrate the metrological basis of NAA, and to establish it as a 'Primary Method of Measurement' will be discussed. (author)

Next-Practise in University Research Based Open Innovation - From Push to Pull: Case Studies from Denmark

DEFF Research Database (Denmark)

Rønnow Lønholdt, Jens; Wilken Bengtsson, Mille; Karlby, Lone Tolstrup

2013-01-01

-graduate education at DTU in design and management of projects in network. It supports competence development within efficient knowledge transfer. Finally conclusions and recommendations will be presented and discussed based on the above six cases within university research based knowledge transfer. © Springer......How do we ensure knowledge transfer from universities in the most effective and efficient way? What is the right balance between a push and a pull approach? These issues have been discussed at length and various methods of intermediary facilitating and ways to organise the transfer have been tried...... in different contextual settings at universities all over the world. Lessons learned are mixed and naturally varies from country to country. This paper presents a recently completed development project concerning the transfer facility at the Technical University of Denmark (DTU). The project focused...

Free-Electron Lasers Push Into New Frontiers

International Nuclear Information System (INIS)

Benson, Stephen V.

2003-01-01

From the early days of the development of free-electron lasers (FELs) the promise of high power and short wavelengths has tantalized physicists and other scientists. Recent developments in accelerator technologies and some new discoveries about the physics of FELs have allowed researchers to push the performance of FELs into new frontiers of high power, short wavelength, and ultra-short pulses. Spin-offs from the FELs have also opened up new radiation sources in the THz, X-ray and gamma ray wavelength ranges

Report on ignitability testing of ''no-flow'' push bit

International Nuclear Information System (INIS)

Witwer, K.S.

1997-01-01

Testing was done to determine if an ignition occurs during a sixty foot drop of a Universal Sampler onto a push-mode bit in a flammable gas environment. Ten drops each of the sampler using both a push-mode and rotary mode insert onto a push-mode bit were completed. No ignition occurred during any of the drops

The Effect of Knowledge Management Systems on Organizational Performance. Do Soldier and Unit Counterinsurgency Knowledge and Performance Improve Following ’Push’ or ’Adaptive-Push’ Training

Science.gov (United States)

2009-01-01

theory.................................................................................................24 Knowles’ theory of andragogy ...theories: Knowles’ andragogy theory and Gagné’s conditions of learning theory. Both may play a role in how a soldier learns during the push and...questions go beyond the scope of this research and will be left for future research. Knowles’ theory of andragogy Knowles’ theory of adult education

Association of the Duration of Active Pushing With Obstetric Outcomes.

Science.gov (United States)

Grobman, William A; Bailit, Jennifer; Lai, Yinglei; Reddy, Uma M; Wapner, Ronald J; Varner, Michael W; Caritis, Steve N; Prasad, Mona; Tita, Alan T N; Saade, George; Sorokin, Yoram; Rouse, Dwight J; Blackwell, Sean C; Tolosa, Jorge E

2016-04-01

To estimate the associations between the duration of active pushing during the second stage of labor and maternal and neonatal outcomes. We performed an observational study in which data were obtained by trained abstractors from maternal and neonatal charts of deliveries at 25 hospitals over a 3-year period. In this secondary analysis, women with no prior cesarean delivery who had a term, singleton, cephalic gestation and reached complete dilation were analyzed. The duration of pushing, defined as the time from initiation of pushing to either vaginal delivery or the decision to proceed with a cesarean delivery, was determined. The primary maternal outcome was cesarean delivery and the primary neonatal outcome was a composite that included: mechanical ventilation, proven sepsis, brachial plexus palsy, clavicular fracture, skull fracture, other fracture, seizures, hypoxic-ischemic encephalopathy, or death. Nulliparous and parous women were analyzed separately in univariable and then multivariable analyses. A total of 53,285 women were analyzed. In both nulliparous and parous women, longer duration of pushing was associated with increased odds of both cesarean delivery and the neonatal adverse outcome composite. Nevertheless, even after 4 hours of pushing, approximately 78% of nulliparous women who continued with active pushing had a vaginal delivery and more than 97% did not have the composite adverse neonatal outcome. Similarly, after more than 2 hours of pushing, approximately 82% of parous women who continued active pushing delivered vaginally and more than 97% did not have the adverse neonatal outcome. A longer duration of pushing is associated with an increased relative risk, but small absolute difference in risk, of neonatal complications. Approximately 78% of nulliparous women delivered vaginally even after 4 hours of pushing.

Young entrepreneurs pushed by necessity and pulled by opportunity

DEFF Research Database (Denmark)

Cheraghi, Maryam

2017-01-01

The vocational choice to be an entrepreneur is made in a social context of institutions in society, which channel, regulate, enable and constrain life, with pushes and pulls. The necessity to make a living may push the entrepreneur, or an opportunity for business may pull the entrepreneur to start....... The push by necessity and pull by opportunity are exerted by institutions in society such as its economy and culture. The purpose here is to account for how young entrepreneurs' experiences of opportunity-pull and necessity-push are influenced by society's economic wealth and culture, as traditional versus...... secular-rational culture and as survival versus self-expression culture. - A sample of 41,281 young entrepreneurs in 93 countries was surveyed in Global Entrepreneurship Monitor. - Analyses show that young entrepreneurs' experience of opportunity-pull rather than necessity-push is not distinctly...

The Uneven Legal Push for Europe

DEFF Research Database (Denmark)

Wind, Marlene; Martinsen, Dorte Sindbjerg; Rotger, Gabriel Pons

2009-01-01

National courts have been key players in the legal push for Europe, though notably to varying degrees. This paper examines the persisting variations in the referral rates of national courts and the underlying causal factors, aiming to better understand why some member states' courts have been more...... reluctant to join in the legal push for Europe. By using econometric methods, it challenges the modified neofunctionalist argument that the extent of intra-EC trade explains the referral practice of the individual member states. Majoritarian democracy is hypothesized as a causal factor in the low referral...... of majoritarian democracy on the number of referrals. The paper concludes that, owing to the uneven legal push for Europe, some member states and their citizens remain at arms' length from the legal integration process - and, in consequence, from the full impact of European integration....

An Analysis of the Effects of Smartphone Push Notifications on Task Performance with regard to Smartphone Overuse Using ERP

Science.gov (United States)

Kim, Seul-Kee; Kim, So-Yeong; Kang, Hang-Bong

2016-01-01

Smartphones are used ubiquitously worldwide and are essential tools in modern society. However, smartphone overuse is an emerging social issue, and limited studies have objectively assessed this matter. The majority of previous studies have included surveys or behavioral observation studies. Since a previous study demonstrated an association between increased push notifications and smartphone overuse, we investigated the effects of push notifications on task performance. We detected changes in brainwaves generated by smartphone push notifications using the N200 and P300 components of event-related potential (ERP) to investigate both concentration and cognitive ability. ERP assessment indicated that, in both risk and nonrisk groups, the lowest N200 amplitude and the longest latency during task performance were found when push notifications were delivered. Compared to the nonrisk group, the risk group demonstrated lower P300 amplitudes and longer latencies. In addition, the risk group featured a higher rate of error in the Go-Nogo task, due to the negative influence of smartphone push notifications on performance in both risk and nonrisk groups. Furthermore, push notifications affected subsequent performance in the risk group. PMID:27366147

An Analysis of the Effects of Smartphone Push Notifications on Task Performance with regard to Smartphone Overuse Using ERP

Directory of Open Access Journals (Sweden)

Seul-Kee Kim

2016-01-01

Full Text Available Smartphones are used ubiquitously worldwide and are essential tools in modern society. However, smartphone overuse is an emerging social issue, and limited studies have objectively assessed this matter. The majority of previous studies have included surveys or behavioral observation studies. Since a previous study demonstrated an association between increased push notifications and smartphone overuse, we investigated the effects of push notifications on task performance. We detected changes in brainwaves generated by smartphone push notifications using the N200 and P300 components of event-related potential (ERP to investigate both concentration and cognitive ability. ERP assessment indicated that, in both risk and nonrisk groups, the lowest N200 amplitude and the longest latency during task performance were found when push notifications were delivered. Compared to the nonrisk group, the risk group demonstrated lower P300 amplitudes and longer latencies. In addition, the risk group featured a higher rate of error in the Go-Nogo task, due to the negative influence of smartphone push notifications on performance in both risk and nonrisk groups. Furthermore, push notifications affected subsequent performance in the risk group.

Tracer gas evaluations of push-pull ventilation system performance.

Science.gov (United States)

Ojima, Jun

2009-01-01

A push-pull ventilation system is effective for hazardous material exhaustion. Although a push-pull ventilation system has advantages over a local exhaust hood, some laborious adjustments are required. The pertinence of the adjustments is uncertain because it is difficult to evaluate the performance of a push-pull ventilation system quantitatively. In this study, a measurement of the capture efficiency of a push-pull ventilation system was carried out by means of a tracer gas method. The capture efficiency decreased to 39.3-78.5% when blockage material, a dummy worker and a cross draft, were set in the ventilation zone, but the efficiency was 95.1-97.9% when the cross draft was stopped. The results suggest that the uniform flow of a push-pull ventilation system will detour a blockage and the performance of the system will not be reduced unless a cross draft disturbs the uniform flow.

An Analysis of the Effects of Smartphone Push Notifications on Task Performance with regard to Smartphone Overuse Using ERP

OpenAIRE

Kim, Seul-Kee; Kim, So-Yeong; Kang, Hang-Bong

2016-01-01

Smartphones are used ubiquitously worldwide and are essential tools in modern society. However, smartphone overuse is an emerging social issue, and limited studies have objectively assessed this matter. The majority of previous studies have included surveys or behavioral observation studies. Since a previous study demonstrated an association between increased push notifications and smartphone overuse, we investigated the effects of push notifications on task performance. We detected changes i...

Push-pull quinoidal porphyrins.

Science.gov (United States)

Smith, Martin J; Blake, Iain M; Clegg, William; Anderson, Harry L

2018-05-01

A family of push-pull quinoidal porphyrin monomers has been prepared from a meso-formyl porphyrin by bromination, thioacetal formation, palladium-catalyzed coupling with malononitrile and oxidation with DDQ. Attempts at extending this synthesis to a push-pull quinoidal/cumulenic porphyrin dimer were not successful. The crystal structures of the quinoidal porphyrins indicate that there is no significant contribution from singlet biradical or zwitterionic resonance forms. The crystal structure of an ethyne-linked porphyrin dimer shows that the torsion angle between the porphyrin units is only about 3°, in keeping with crystallographic results on related compounds, but contrasting with the torsion angle of about 35° predicted by computational studies. The free-base quinoidal porphyrin monomers form tightly π-stacked layer structures, despite their curved geometries and bulky aryl substituents.

INTERSESSION RELIABILITY OF UPPER EXTREMITY ISOKINETIC PUSH-PULL TESTING.

Science.gov (United States)

Riemann, Bryan L; Davis, Sarah E; Huet, Kevin; Davies, George J

2016-02-01

Based on the frequency pushing and pulling patterns are used in functional activities, there is a need to establish an objective method of quantifying the muscle performance characteristics associated with these motions, particularly during the later stages of rehabilitation as criteria for discharge. While isokinetic assessment offers an approach to quantifying muscle performance, little is known about closed kinetic chain (CKC) isokinetic testing of the upper extremity (UE). To determine the intersession reliability of isokinetic upper extremity measurement of pushing and pulling peak force and average power at slow (0.24 m/s), medium (0.43 m/s) and fast (0.61 m/s) velocities in healthy young adults. The secondary purpose was to compare pushing and pulling peak force (PF) and average power (AP) between the upper extremity limbs (dominant, non-dominant) across the three velocities. Twenty-four physically active men and women completed a test-retest (>96 hours) protocol in order to establish isokinetic UE CKC reliability of PF and AP during five maximal push and pull repetitions at three velocities. Both limb and speed orders were randomized between subjects. High test-retest relative reliability using intraclass correlation coefficients (ICC2, 1) were revealed for PF (.91-.97) and AP (.85-.95) across velocities, limbs and directions. PF typical error (% coefficient of variation) ranged from 6.1% to 11.3% while AP ranged from 9.9% to 26.7%. PF decreased significantly (p pushing were significantly greater than pulling at all velocities, however the push-pull differences in PF became less as velocity increased. There were no significant differences identified between the dominant and nondominant limbs. Isokinetically derived UE CKC push-pull PF and AP are reliable measures. The lack of limb differences in healthy normal participants suggests that clinicians can consider bilateral comparisons when interpreting test performance. The increase in pushing PF and

Does delayed pushing in the second stage of labor impact perinatal outcomes?

Science.gov (United States)

Frey, Heather A; Tuuli, Methodius G; Cortez, Sarah; Odibo, Anthony O; Roehl, Kimberly A; Shanks, Anthony L; Macones, George A; Cahill, Alison G

2012-11-01

To estimate maternal, neonatal, and labor outcomes associated with delayed pushing. A retrospective cohort study of all consecutive women admitted to a single institution in labor at term who reached the second stage of labor. Pregnancies with multiple fetuses or major anomalies were excluded. Delayed pushing was defined as initiation of pushing ≥60 minutes after complete dilatation. Primary outcome was mode of delivery. Multivariable logistic regression was used to control for confounding. Of the 5290 women who met inclusion criteria, 471 (8.9%) employed delayed pushing, and 4819 (91.1%) pushed immediately. Delayed pushing was associated with increased rates of cesarean, operative vaginal delivery, maternal fever, and lower arterial cord pH. Duration of the second stage and length of time spent pushing were significantly longer with delayed pushing. Delayed pushing is associated with lower rates of spontaneous vaginal delivery and increased adverse maternal and neonatal outcomes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Psychophysical basis for maximum pushing and pulling forces: A review and recommendations.

Science.gov (United States)

Garg, Arun; Waters, Thomas; Kapellusch, Jay; Karwowski, Waldemar

2014-03-01

The objective of this paper was to perform a comprehensive review of psychophysically determined maximum acceptable pushing and pulling forces. Factors affecting pushing and pulling forces are identified and discussed. Recent studies show a significant decrease (compared to previous studies) in maximum acceptable forces for males but not for females when pushing and pulling on a treadmill. A comparison of pushing and pulling forces measured using a high inertia cart with those measured on a treadmill shows that the pushing and pulling forces using high inertia cart are higher for males but are about the same for females. It is concluded that the recommendations of Snook and Ciriello (1991) for pushing and pulling forces are still valid and provide reasonable recommendations for ergonomics practitioners. Regression equations as a function of handle height, frequency of exertion and pushing/pulling distance are provided to estimate maximum initial and sustained forces for pushing and pulling acceptable to 75% male and female workers. At present it is not clear whether pushing or pulling should be favored. Similarly, it is not clear what handle heights would be optimal for pushing and pulling. Epidemiological studies are needed to determine relationships between psychophysically determined maximum acceptable pushing and pulling forces and risk of musculoskeletal injuries, in particular to low back and shoulders.

Inclusion at Risk? Push- and Pull-Out Phenomena in Inclusive School Systems: The Italian and Norwegian Experiences

Science.gov (United States)

Nes, Kari; Demo, Heidrun; Ianes, Dario

2018-01-01

The main objective of this article is to explore and compare research data on pull-out and push-out phenomena within inclusive school systems, discussing if and how they represent a risk for inclusion. The terms pull-out and push-out refer to situations in which some groups of students in regular schools learn in settings apart from their peers.…

Pushing and pulling in relation to musculoskeletal complaints

NARCIS (Netherlands)

Hoozemans, M. J M; Van Der Beek, Allard J.; Frings-Dresen, M. H. W.

2000-01-01

The first cross-sectional analyses are presented of a longitudinal study regarding the relationship between pushing and pulling and musculoskeletal disorders. Workers exposed to pushing and pulling and workers who had administrative tasks received a questionnaire. A significant association between

An investigation of rugby scrimmaging posture and individual maximum pushing force.

Science.gov (United States)

Wu, Wen-Lan; Chang, Jyh-Jong; Wu, Jia-Hroung; Guo, Lan-Yuen

2007-02-01

Although rugby is a popular contact sport and the isokinetic muscle torque assessment has recently found widespread application in the field of sports medicine, little research has examined the factors associated with the performance of game-specific skills directly by using the isokinetic-type rugby scrimmaging machine. This study is designed to (a) measure and observe the differences in the maximum individual pushing forward force produced by scrimmaging in different body postures (3 body heights x 2 foot positions) with a self-developed rugby scrimmaging machine and (b) observe the variations in hip, knee, and ankle angles at different body postures and explore the relationship between these angle values and the individual maximum pushing force. Ten national rugby players were invited to participate in the examination. The experimental equipment included a self-developed rugby scrimmaging machine and a 3-dimensional motion analysis system. Our results showed that the foot positions (parallel and nonparallel foot positions) do not affect the maximum pushing force; however, the maximum pushing force was significantly lower in posture I (36% body height) than in posture II (38%) and posture III (40%). The maximum forward force in posture III (40% body height) was also slightly greater than for the scrum in posture II (38% body height). In addition, it was determined that hip, knee, and ankle angles under parallel feet positioning are factors that are closely negatively related in terms of affecting maximum pushing force in scrimmaging. In cross-feet postures, there was a positive correlation between individual forward force and hip angle of the rear leg. From our results, we can conclude that if the player stands in an appropriate starting position at the early stage of scrimmaging, it will benefit the forward force production.

Muscle Activation during Push-Ups with Different Suspension Training Systems.

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Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan C; Martín, Fernando F; Rogers, Michael E; Behm, David G; Andersen, Lars L

2014-09-01

The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29) performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation. Key PointsCompared with standard push-ups on the floor, suspended push-ups increase core muscle activation.A one-anchor system with a pulley is the best option to increase TRICEP, TRAPS, LUMB and FEM muscle activity.More stable conditions such as the standard push-up or a parallel band system provide greater increases in DELT and PEC muscle activation.A suspended push-up is an effective method to achieve high muscle activity levels in the ABS.

Effects of pushing techniques during the second stage of labor: A randomized controlled trial

Directory of Open Access Journals (Sweden)

Refika Genç Koyucu

2017-10-01

Conclusions: Although the duration of the second stage of labor was longer compared to valsalva pushing technique, women were able to give birth without requiring any verbal or visual instruction, without exceeding the limit value of two hours and without affecting fetal wellness and neonatal results.

Push-out strength of modified Portland cements and resins.

Science.gov (United States)

Iacono, Francesco; Gandolfi, Maria Giovanna; Huffman, Bradford; Sword, Jeremy; Agee, Kelli; Siboni, Francesco; Tay, Franklin; Prati, Carlo; Pashley, David

2010-02-01

Modified calcium-silicate cements derived from white Portland cement (PC) were formulated to test their push-out strength from radicular dentin after immersion for 1 month. Slabs obtained from 42 single-rooted extracted teeth were prepared with 0.6 mm diameter holes, then enlarged with rotary instruments. After immersion in EDTA and NaOC1, the holes were filled with modified PCs or ProRoot MTA, Vitrebond and Clearfil SE. Different concentrations of phyllosilicate (montmorillonite-MMT) were added to experimental cements. ProRoot MTA was also included as reference material. Vitrebond and Clearfil SE were included as controls. Each group was tested after 1 month of immersion in water or PBS. A thin-slice push-out test on a universal testing machine served to test the push-out strength of materials. Results were statistically analyzed using the least squares means (LSM) method. The modified PCs had push-out strengths of 3-9.5 MPa after 1 month of immersion in water, while ProRoot MTA had 4.8 MPa. The push-out strength of PC fell after incubation in PBS for 1 month, while the push-out strength of ProRoot MTA increased. There were no significant changes in Clearfil SE Bond or Vitrebond after water or PBS storage.

数字电视广告系统的推送技术研究%Push Technology of Digital Television Advertising System Research

Institute of Scientific and Technical Information of China (English)

王猛; 单海华

2016-01-01

首先简要介绍数字电视行业的技术发展背景，其次介绍数字电视系统的机顶盒及广告推送技术，以及 EPG系统技术的方向研究，讨论并采用移动公司运营商平台的大数据来甄选特殊客户需求，主要研究基于Huffman编码的EPG广告系统针对特定用户的广告推送，最后对相关理论和技术的发展进行讨论和实现。%First briefly introduced the technology development of digital TV industry background,secondly introduces digital TV set-top boxes and advertising push technology in the system,and the direction of the EPG system technology research. Dis-cussed and adopted mobile operator platform of data to the selection of a specific customer requirement,main research based on Huffman coding the EPG advertisement system for specific user advertising push. Finally,the development of related theories and technologies were discussed and implemented.

Push-Back Leadership.

Science.gov (United States)

Tetenbaum, Toby J.; Tetenbaum, Hilary

2003-01-01

Describes push-back leadership, a model of leadership based on the work of Ronald Heifetz and Martin Linksky. Argues that the two key roles of the leader are to give the work back to people and to keep them within a healthy range of disequilibrium that generates creativity and innovation to solve organizational problems. (Author/LRW)

Effects of pushing techniques in birth on mother and fetus: a randomized study.

Science.gov (United States)

Yildirim, Gulay; Beji, Nezihe Kizilkaya

2008-03-01

The Valsalva pushing technique is used routinely in the second stage of labor in many countries, and it is accepted as standard obstetric management in Turkey. The purpose of this study was to determine the effects of pushing techniques on mother and fetus in birth in this setting. This randomized study was conducted between July 2003 and June 2004 in Bakirkoy Maternity and Children's Teaching Hospital in Istanbul, Turkey. One hundred low-risk primiparas between 38 and 42 weeks' gestation, who expected a spontaneous vaginal delivery, were randomized to either a spontaneous pushing group or a Valsalva-type pushing group. Spontaneous pushing women were informed during the first stage of labor about spontaneous pushing technique (open glottis pushing while breathing out) and were supported in pushing spontaneously in the second stage of labor. Similarly, Valsalva pushing women were informed during the first stage of labor about the Valsalva pushing technique (closed glottis pushing while holding their breath) and were supported in using Valsalva pushing in the second stage of labor. Perineal tears, postpartum hemorrhage, and hemoglobin levels were evaluated in mothers; and umbilical artery pH, Po(2) (mmHg), and Pco(2) (mmHg) levels and Apgar scores at 1 and 5 minutes were evaluated in newborns in both groups. No significant differences were found between the two groups in their demographics, incidence of nonreassuring fetal surveillance patterns, or use of oxytocin. The second stage of labor and duration of the expulsion phase were significantly longer with Valsalva-type pushing. Differences in the incidence of episiotomy, perineal tears, or postpartum hemorrhage were not significant between the groups. The baby fared better with spontaneous pushing, with higher 1- and 5-minute Apgar scores, and higher umbilical cord pH and Po(2) levels. After the birth, women expressed greater satisfaction with spontaneous pushing. Educating women about the spontaneous pushing

Transformation from a Single Antenna to a Series Array Using Push/Pull Origami

Directory of Open Access Journals (Sweden)

Syed Imran Hussain Shah

2017-08-01

Full Text Available We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5–2.65 GHz and 2.48–2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

Transformation from a Single Antenna to a Series Array Using Push/Pull Origami.

Science.gov (United States)

Shah, Syed Imran Hussain; Lim, Sungjoon

2017-08-26

We propose a push/pull origami antenna, transformable between a single antenna element and a three-element array. In limited space, the proposed origami antenna can work as a single antenna. When the space is not limited and a higher gain is required, the proposed origami antenna can be transformed to a series antenna array by pulling the frame. In order to push the antenna array back to a single antenna, the frame for each antenna element size must be different. The frame and supporting dielectric materials are built using a three-dimensional (3D) printer. The conductive patterns are inkjet-printed on paper. Thus, the proposed origami antenna is built using hybrid printing technology. The 10-dB impedance bandwidth is 2.5-2.65 GHz and 2.48-2.62 GHz for the single-antenna and array mode, respectively, and the peak gains in the single-antenna and array mode are 5.8 dBi and 7.6 dBi, respectively. The proposed antenna can be used for wireless remote-sensing applications.

Controlled manipulation of flexible carbon nanotubes through shape-dependent pushing by atomic force microscopy.

Science.gov (United States)

Yang, Seung-Cheol; Qian, Xiaoping

2013-09-17

A systematic approach to manipulating flexible carbon nanotubes (CNTs) has been developed on the basis of atomic force microscope (AFM) based pushing. Pushing CNTs enables efficient transport and precise location of individual CNTs. A key issue for pushing CNTs is preventing defective distortion in repetitive bending and unbending deformation. The approach presented here controls lateral movement of an AFM tip to bend CNTs without permanent distortion. The approach investigates possible defects caused by tensile strain of the outer tube under uniform bending and radial distortion by kinking. Using the continuum beam model and experimental bending tests, dependency of maximum bending strain on the length of bent CNTs and radial distortion on bending angles at a bent point have been demonstrated. Individual CNTs are manipulated by limiting the length of bent CNTs and the bending angle. In our approach, multiwalled CNTs with 5-15 nm diameter subjected to bending deformation produce no outer tube breakage under uniform bending and reversible radial deformation with bending angles less than 110°. The lateral tip movement is determined by a simple geometric model that relies on the shape of multiwalled CNTs. The model effectively controls deforming CNT length and bending angle for given CNT shape. Experimental results demonstrate successful manipulation of randomly dispersed CNTs without visual defects. This approach to pushing can be extended to develop a wide range of CNT based nanodevice applications.

Effect of External Loading on Force and Power Production During Plyometric Push-ups.

Science.gov (United States)

Hinshaw, Taylour J; Stephenson, Mitchell L; Sha, Zhanxin; Dai, Boyi

2018-04-01

Hinshaw, TJ, Stephenson, ML, Sha, Z, and Dai, B. Effect of external loading on force and power production during plyometric push-ups. J Strength Cond Res 32(4): 1099-1108, 2018-One common exercise to train upper-body strength and power is the push-up. Training at the loads that would produce the greatest power is an effective way to increase peak power. The purpose of the current study was to quantify the changes in peak force, peak power, and peak velocity among a modified plyometric push-up and plyometric push-ups with or without external loading in physically active young adults. Eighteen male and 17 female participants completed 4 push-ups: (a) modified plyometric push-up on the knees, (b) plyometric push-up without external loading, (c) plyometric push-up with an external load of 5% of body weight, and (d) plyometric push-up with an external load of 10% of body weight. Two force platforms were set up to collect vertical ground reaction forces at the hands and feet. The modified plyometric push-up demonstrated the lowest force, power, and velocity (5.4≥ Cohen's dz ≥1.2). Peak force and force at peak velocity increased (3.8≥ Cohen's dz ≥0.3) and peak velocity and velocity at peak power decreased (1.4≥ Cohen's dz ≥0.8) for the push-up without external loading compared with the 2 push-ups with external loading. No significant differences were observed for peak power among the push-ups with or without external loading (0.4≥ Cohen's dz ≥0.1). Although peak power is similar with or without external loading, push-ups without external loading may be more beneficial for a quick movement, and push-ups with external loading may be more beneficial for a greater force production.

Trustworthy content push

OpenAIRE

Kuntze, Nicolai; Schmidt, Andreas U.

2006-01-01

Delivery of content to mobile devices gains increasing importance in industrial environments to support employees in the field. An important application are e-mail push services like the fashionable Blackberry. These systems are facing security challenges regarding data transport to, and storage of the data on the end user equipment. The emerging Trusted Computing technology offers new answers to these open questions.

Do PhDs Voluntarily Opt for Private Sector Employment? Evidence of Push and Pull Effects on Mobility Choices

DEFF Research Database (Denmark)

Pedersen, Heidi Skovgaard

2014-01-01

In Denmark, policy makers have increased admissions to PhD programs to ensure the flow of researchers into the private sector, thereby increasing knowledge transfer. However, we know little about the factors influencing the sector mobility of PhD graduates. While opting for employment...... in the private sector might be driven by personal preferences, there might also be external factors pushing PhDs to choose the private sector. This article examines the push and pull effects on mobility choices using duration models to estimate the transition rates to private sector employment. The analyses show...... that the preference for and ability to do academic science reduces transition rates to the private sector, whereas being in a research position and earnings potential are attractors to the private sector. Hence, both push and pull effects determine sector mobility. Once the initial sector choice has been made...

40 CFR 63.7290 - What emission limitations must I meet for capture systems and control devices applied to pushing...

Science.gov (United States)

2010-07-01

... to you for a new or existing coke oven battery. (1) For each venturi scrubber applied to pushing emissions, you must maintain the daily average pressure drop and scrubber water flow rate at or above the... to capture emissions; (3) If a mobile scrubber car that does not capture emissions during travel is...

Effect of different pushing speeds on bench press.

Science.gov (United States)

Padulo, J; Mignogna, P; Mignardi, S; Tonni, F; D'Ottavio, S

2012-05-01

The purpose of this study was to investigate the effect on muscular strength after a 3-week training with the bench-press at a fixed pushing of 80-100% maximal speed (FPS) and self-selected pushing speed (SPS). 20 resistance-trained subjects were divided at random in 2 groups differing only regarding the pushing speed: in the FPS group (n=10) it was equal to 80-100% of the maximal speed while in the SPS group (n=10) the pushing speed was self-selected. Both groups were trained twice a week for 3 weeks with a load equal to 85% of 1RM and monitored with the encoder. Before and after the training we measured pushing speed and maximum load. Significant differences between and within the 2 groups were pointed out using a 2-way ANOVA for repeated measures. After 3 weeks a significant improvement was shown especially in the FPS group: the maximum load improved by 10.20% and the maximal speed by 2.22%, while in the SPS group the effect was <1%. This study shows that a high velocity training is required to increase the muscle strength further in subjects with a long training experience and this is possible by measuring the individual performance speed for each load. © Georg Thieme Verlag KG Stuttgart · New York.

A unified perspective on ankle push-off in human walking.

Science.gov (United States)

Zelik, Karl E; Adamczyk, Peter G

2016-12-01

Muscle-tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two possibilities are not mutually exclusive. If we ask either question independently, the answer is the same: yes! (1) Does ankle push-off primarily contribute to leg swing acceleration? Yes. (2) Does ankle push-off primarily contribute to COM acceleration? Yes. Here, we summarize the historical debate, then synthesize the seemingly polarized perspectives and demonstrate that both descriptions are valid. The principal means by which ankle push-off affects COM mechanics is by a localized action that increases the speed and kinetic energy of the trailing push-off limb. Because the limb is included in body COM computations, this localized segmental acceleration also accelerates the COM, and most of the segmental energy change also appears as COM energy change. Interpretation of ankle mechanics should abandon an either/or contrast of leg swing versus COM acceleration. Instead, ankle push-off should be interpreted in light of both mutually consistent effects. This unified perspective informs our fundamental understanding of the role of ankle push-off, and has important implications for the design of clinical interventions (e.g. prostheses, orthoses) intended to restore locomotor function to individuals with disabilities. © 2016. Published by The Company of Biologists Ltd.

From Source to Sink: Mechanistic Reasoning Using the Electron-Pushing Formalism

Science.gov (United States)

Bhattacharyya, Gautam

2013-01-01

Since the introduction of Morrison and Boyd's textbook in organic chemistry over 50 years ago, reaction mechanisms and mechanistic reasoning using the electron-pushing formalism (EPF) have become a mainstay of organic chemistry courses. In recent years there have even been several papers in this Journal and others detailing research on how…

Pushing, pulling and manoeuvring an industrial cart: a psychophysiological study.

Science.gov (United States)

Giagloglou, Evanthia; Radenkovic, Milan; Brankovic, Sasa; Antoniou, Panagiotis; Zivanovic-Macuzic, Ivana

2017-09-18

One of the most frequent manual occupational tasks involves the pushing and pulling of a cart. Although several studies have associated health risks with pushing and pulling, the effects are not clear since occupational tasks have social, cognitive and physical components. The present work investigates a real case of a pushing and pulling occupational task from a manufacturing company. The study initially characterizes the case in accordance with Standard No. ISO 11228-2:2007 as low risk. An experiment with 14 individuals during three modalities of pushing and pulling was performed in order to further investigate the task with the application of electrophysiology. At the end, a simple questionnaire was given. The results show electrophysiological differences among the three modalities of pushing and pulling, with a major difference between action with no load and fully loaded with a full range of motions on the cart to handle.

Spontaneous pushing to prevent postpartum urinary incontinence: a randomized, controlled trial.

Science.gov (United States)

Low, Lisa Kane; Miller, Janis M; Guo, Ying; Ashton-Miller, James A; DeLancey, John O L; Sampselle, Carolyn M

2013-03-01

The risk for urinary incontinence can be 2.6-fold greater in women after pregnancy and childbirth compared with their never-pregnant counterparts, with the incidence increasing with parity. We tested the hypothesis that the incidence of de novo postpartum urinary incontinence in primiparous women is reduced with the use of spontaneous pushing alone or in combination with perineal massage compared with women who experienced traditional directed pushing for second-stage management. This was a prospective clinical trial enrolling and randomizing 249 women into a four-group design: (1) routine care with coached or directed pushing, (2) spontaneous self-directed pushing, (3) prenatal perineal massage initiated in the third trimester, and (4) the combination of spontaneous pushing plus perineal massage. Self-report of incontinence was assessed using analysis of variance (ANOVA) and covariance (ANCOVA) models in 145 remaining women at 12 months postpartum using the Leakage Index, which is sensitive to minor leakage. No statistical difference in the incidence of de novo postpartum incontinence was found based on method of pushing (spontaneous/directed) (P value = 0.57) or in combination with prenatal perineal massage (P value = 0.57). Fidelity to pushing treatment of type was assessed and between-groups crossover detected. Spontaneous pushing did not reduce the incidence of postpartum incontinence experienced by women 1 year after their first birth due to high cross-over between randomization groups.

Pushing the Limits of Military Coercion Theory

DEFF Research Database (Denmark)

Jakobsen, Peter Viggo

2011-01-01

by coercion theorists is that coercion is hard and that miscalculation, misperception, or practical problems can defeat even a perfectly executed strategy. What they ignore is that the problem also stems from the limits of coercion theory, which has left us with an unnecessarily poor understanding of how...... military coercion works and how the practical problems involved could be addressed. Our understanding of military coercion would be increased markedly if only coercion theorists would make a greater efforts to do three things, namely (1) provide clear operational definitions of key concepts and variables...

Field evaluation of a direct push deployed sensor probe for vertical soil water content profiling

Science.gov (United States)

Vienken, Thomas; Reboulet, Ed; Leven, Carsten; Kreck, Manuel; Zschornack, Ludwig; Dietrich, Peter

2015-04-01

Reliable high-resolution information about vertical variations in soil water content, i.e. total porosity in the saturated zone, is essential for flow and transport predictions within the subsurface. However, porosity measurements are often associated with high efforts and high uncertainties, e.g. caused by soil disturbance during sampling or sensor installation procedures. In hydrogeological practice, commonly applied tools for the investigation of vertical soil water content distribution include gravimetric laboratory analyses of soil samples and neutron probe measurements. A yet less well established technique is the use of direct push-deployed sensor probes. Each of these methods is associated with inherent advantages and limitations due to their underlying measurement principles and operation modes. The presented study describes results of a joint field evaluation of the individual methods under different depositional and hydrogeological conditions with special focus on the performance on the direct push-deployed water content profiler. Therefore, direct push-profiling results from three different test sites are compared with results obtained from gravimetric analysis of soil cores and neutron probe measurements. In direct comparison, the applied direct push-based sensor probe proved to be a suitable alternative for vertical soil water content profiling to neutron probe technology, and, in addition, proved to be advantageous over gravimetric analysis in terms vertical resolution and time efficiency. Results of this study identify application-specific limitations of the methods and thereby highlight the need for careful data evaluation, even though neutron probe measurements and gravimetric analyses of soil samples are well established techniques (see Vienken et al. 2013). Reference: Vienken, T., Reboulet, E., Leven, C., Kreck, M., Zschornack, L., Dietrich, P., 2013. Field comparison of selected methods for vertical soil water content profiling. Journal of

Chemo-mechanical pushing of proteins along single-stranded DNA.

Science.gov (United States)

Sokoloski, Joshua E; Kozlov, Alexander G; Galletto, Roberto; Lohman, Timothy M

2016-05-31

Single-stranded (ss)DNA binding (SSB) proteins bind with high affinity to ssDNA generated during DNA replication, recombination, and repair; however, these SSBs must eventually be displaced from or reorganized along the ssDNA. One potential mechanism for reorganization is for an ssDNA translocase (ATP-dependent motor) to push the SSB along ssDNA. Here we use single molecule total internal reflection fluorescence microscopy to detect such pushing events. When Cy5-labeled Escherichia coli (Ec) SSB is bound to surface-immobilized 3'-Cy3-labeled ssDNA, a fluctuating FRET signal is observed, consistent with random diffusion of SSB along the ssDNA. Addition of Saccharomyces cerevisiae Pif1, a 5' to 3' ssDNA translocase, results in the appearance of isolated, irregularly spaced saw-tooth FRET spikes only in the presence of ATP. These FRET spikes result from translocase-induced directional (5' to 3') pushing of the SSB toward the 3' ssDNA end, followed by displacement of the SSB from the DNA end. Similar ATP-dependent pushing events, but in the opposite (3' to 5') direction, are observed with EcRep and EcUvrD (both 3' to 5' ssDNA translocases). Simulations indicate that these events reflect active pushing by the translocase. The ability of translocases to chemo-mechanically push heterologous SSB proteins along ssDNA provides a potential mechanism for reorganization and clearance of tightly bound SSBs from ssDNA.

Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers

Science.gov (United States)

Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

2016-01-01

The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and (c) the jumper's perception of the position of his MC relative to the ground reaction force, during push-off, to reduce energetic losses. PMID:27486404

Fast Regulation of Vertical Squat Jump during push-off in skilled jumpers

Directory of Open Access Journals (Sweden)

Patrick FARGIER

2016-07-01

Full Text Available The height of a maximum Vertical Squat Jump (VSJ reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realised in a very short time (ca. 300ms, compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research.Eight young adult volunteers (males performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball. A video analysis on the kinematics of the jump determined the influence of the jumpers’ segments rotation on the vertical velocity and acceleration of the body mass center (MC. The efficiency in the production of useful power at the jumpers’ MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s.Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s of the VSJ may be supported by: (a the adaptation of the motor cerebral programming to the jumper’s physical characteristics; (b the control of the initial posture; and (c the jumper’s perception of the position of his MC relative to the ground reaction force during push-off to reduce energetic losses.

Fast Regulation of Vertical Squat Jump during Push-Off in Skilled Jumpers.

Science.gov (United States)

Fargier, Patrick; Massarelli, Raphael; Rabahi, Tahar; Gemignani, Angelo; Fargier, Emile

2016-01-01

The height of a maximum Vertical Squat Jump (VSJ) reflects the useful power produced by a jumper during the push-off phase. In turn this partly depends on the coordination of the jumper's segmental rotations at each instant. The physical system constituted by the jumper has been shown to be very sensitive to perturbations and furthermore the movement is realized in a very short time (ca. 300 ms), compared to the timing of known feedback loops. However, the dynamics of the segmental coordination and its efficiency in relation to energetics at each instant of the push-off phase still remained to be clarified. Their study was the main purpose of the present research. Eight young adult volunteers (males) performed maximal VSJ. They were skilled in jumping according to their sport activities (track and field or volleyball). A video analysis on the kinematics of the jump determined the influence of the jumpers' segments rotation on the vertical velocity and acceleration of the body mass center (MC). The efficiency in the production of useful power at the jumpers' MC level, by the rotation of the segments, was measured in consequence. The results showed a great variability in the segmental movements of the eight jumpers, but homogeneity in the overall evolution of these movements with three consecutive types of coordination in the second part of the push-off (lasting roughly 0.16 s). Further analyses gave insights on the regulation of the push-off, suggesting that very fast regulation(s) of the VSJ may be supported by: (a) the adaptation of the motor cerebral programming to the jumper's physical characteristics; (b) the control of the initial posture; and (c) the jumper's perception of the position of his MC relative to the ground reaction force, during push-off, to reduce energetic losses.

Intra and interobserver variability of intrapartum transperineal ultrasound measurements with contraction and pushing.

Science.gov (United States)

Sainz, José A; Fernández-Palacín, Ana; Borrero, Carlota; Aquise, Adriana; Ramos, Zenaida; García-Mejido, José A

2018-04-01

The aim of this study was to evaluate the inter- and intraobserver correlation of the different intrapartum-transperineal-ultrasound-parameters(ITU) (angle of progression (AoP), progression-distance (PD), head-direction (HD), midline-angle (MLA) and head-perineum distance (HPD)) with contraction and pushing. We evaluated 28 nulliparous women at full dilatation under epidural analgesia. We performed a transperineal ultrasound evaluating AoP and PD in the longitudinal plane, and MLA and HPD in the transverse plane. Interclass correlation coefficients (ICC) with 95% CIs and Bland-Altman analysis were used to assess intra- and interobserver measurement's repeatability. The ICC of the ITU for the same observer was adequate for all the parameters (p pushing under epidural analgesia. Impact statement What is already known on this subject: The intrapartum transperineal ultrasound parameters can be used with contraction and pushing under epidural analgesia. What the results of this study add to what we know: ITU may be used to evaluate the difficulty of instrumental delivery/to evaluate the difficulty of instrumentation in vaginal operative deliveries and this study concludes that ITU is reproducible during uterine contraction with pushing. What the implications are of these findings for clinical practice and/or further research: Therefore, ITU could be used without difficulty with an adequate intra- and interobserver correlation for the prediction of instrumentation difficulty in operative vaginal deliveries.

Medical and nonmedical factors influencing utilization of delayed pushing in the second stage.

Science.gov (United States)

Frey, Heather A; Tuuli, Methodius G; Cortez, Sarah; Odibo, Anthony O; Roehl, Kimberly A; Shanks, Anthony L; Macones, George A; Cahill, Alison G

2013-08-01

To evaluate factors impacting selection to delayed pushing in the second stage of labor. This case-control study was a secondary analysis of a large retrospective cohort study. Cases included women who delayed pushing for 60 minutes or more in the second stage of labor. Controls began pushing prior to 60 minutes from the time of diagnosis of complete dilation. Demographic, labor, and nonmedical factors were compared among cases and controls. Logistic regression modeling was used to identify factors independently associated with delayed pushing. We identified 471 women who delayed pushing and 4819 controls. Nulliparity, maternal body mass index > 25, high fetal station at complete dilation, regional anesthesia use, and start of second stage during staffing shift change were independent factors associated with increased use of delayed pushing. On the other hand, black race and second-stage management during night shift were associated with lower odds of employing delayed pushing. Delayed pushing was more commonly employed in nulliparous women, but 38.9% of multiparous women also delayed pushing. We identified multiple factors associated with use of delayed pushing. This study helps to define current patterns of second-stage labor management. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Shoulder joint loading and posture during medicine cart pushing task.

Science.gov (United States)

Xu, Xu; Lin, Jia-Hua; Boyer, Jon

2013-01-01

Excessive physical loads and awkward shoulder postures during pushing and pulling are risk factors for shoulder pain. Pushing a medicine cart is a major component of a work shift for nurses and medical assistants in hospitals and other health care facilities. A laboratory experiment was conducted to examine the effects of common factors (e.g., lane congestion, cart load stability, floor surface friction) on shoulder joint moment and shoulder elevation angle of participants during cart pushing. Participants pushed a medicine cart on straight tracks and turning around right-angle corners. Peak shoulder joint moments reached 25.1 Nm, 20.3 Nm, and 26.8 Nm for initial, transition, and turning phases of the pushing tasks, indicating that shoulder joint loading while pushing a medical cart is comparable to levels previously reported from heavy manual activities encountered in industry (e.g., garbage collection). Also, except for user experience, all other main study factors, including congestion level, cart load stability, location of transition strip, shoulder tendency, surface friction, and handedness, significantly influenced shoulder joint moment and shoulder elevation angle. The findings provide a better understanding of shoulder exposures associated with medicine cart operations and may be helpful in designing and optimizing the physical environment where medicine carts are used.

Motivation and Perception of Tourists as Push and Pull Factors to Visit National Park

Science.gov (United States)

Said, Jumrin; Maryono

2018-02-01

Push-pull theoretical framework is a popular theory to explain the reason why the tourists decide to visit the destination rather than other place, the kind of experience they want to get and the type of activity they want to do. In this paper, it is explained the motivation as push factors and the perception as pull factors of the tourist in deciding the destination based on previous literature and research using descriptive method. The framework asumed that tourists are motivated to fulfill their needs, including to reduce the psychological imbalance and to gain recognition of social status. National Park is one of destination based on nature or commonly knowns as ecotourism. In choosing the destination, the tourists tend to classify their alternative choice based on several criteria, such as the domination perception of tourist from one destination (pull factor), self motivation (push factor) and the available time and money (situational constraints).

Synthesizing a novel genetic sequential logic circuit: a push-on push-off switch.

Science.gov (United States)

Lou, Chunbo; Liu, Xili; Ni, Ming; Huang, Yiqi; Huang, Qiushi; Huang, Longwen; Jiang, Lingli; Lu, Dan; Wang, Mingcong; Liu, Chang; Chen, Daizhuo; Chen, Chongyi; Chen, Xiaoyue; Yang, Le; Ma, Haisu; Chen, Jianguo; Ouyang, Qi

2010-01-01

Design and synthesis of basic functional circuits are the fundamental tasks of synthetic biologists. Before it is possible to engineer higher-order genetic networks that can perform complex functions, a toolkit of basic devices must be developed. Among those devices, sequential logic circuits are expected to be the foundation of the genetic information-processing systems. In this study, we report the design and construction of a genetic sequential logic circuit in Escherichia coli. It can generate different outputs in response to the same input signal on the basis of its internal state, and 'memorize' the output. The circuit is composed of two parts: (1) a bistable switch memory module and (2) a double-repressed promoter NOR gate module. The two modules were individually rationally designed, and they were coupled together by fine-tuning the interconnecting parts through directed evolution. After fine-tuning, the circuit could be repeatedly, alternatively triggered by the same input signal; it functions as a push-on push-off switch.

Pushed news: when the news comes to the cellphone

Directory of Open Access Journals (Sweden)

Antonio Fidalgo

2009-12-01

Full Text Available Combining two findings of recent surveys on the Internet which state that 1 “the Internet will soon surpass all other media as a main source for national and international news” and 2 “the mobile device will be the primary connection tool to the Internet in 2020” leads us to the conclusion that smartphones will soon be the primary source for news access. But if so, how will news come to the Internetconnected cellphones? In accordance with the distinction, already drawn in 1997, between push and pull technologies as two different forms of how content is delivered to the end users, cellphones are characterized as push devices (passive reception, in opposition to computers, classified as pull devices (active reception. The news items that fit cellphones are pushed news. And they will be pushed as SMS, e-mails, tweets and through news aggregators.

PUSHED NEWS: When the news comes to the cellphone

Directory of Open Access Journals (Sweden)

Antonio Fidalgo

2009-12-01

Full Text Available Combining two findings of recent surveys on the Internet whichstate that 1 “the Internet will soon surpass all other media as a main source for national and international news” and 2 “the mobile device will be the primary connection tool to the Internet in 2020” leads us to the conclusion that smartphones will soon be the primary source for news access. But if so, how will news come to the Internetconnected cellphones? In accordance with the distinction, already drawn in 1997, between push and pull technologies as two different forms of how content is delivered to the end users, cellphones are characterized as push devices (passive reception, in opposition to computers, classified as pull devices (active reception. The news items that fit cellphones are pushed news. And they will be pushed as SMS, e-mails, tweets and through news aggregators.

Push-out bond strength of different tricalcium silicate-based filling materials to root dentin

Directory of Open Access Journals (Sweden)

Jorge Henrique Stefaneli Marques

2018-03-01

Full Text Available Abstract: The aim of this study was to evaluate the bond strength of different triccalcium silicate cements to retrograde cavity using a push out test. Thirty maxillary central incisors were shaped using #80 hand files and sectioned transversally. Root slices were obtained from the apical 4 mm after eliminating the apical extremity. The specimens were embedded in acrylic resin and positioned at 45° to the horizontal plane for preparation of root-end cavities with a diamond ultrasonic retrotip. The samples were divided into three groups according to the root-end filling material (n = 10: MTA Angelus, ProRoot MTA and Biodentine. A gutta-percha cone (#80 was tugged-back at the limit between the canal and the root-end cavity. The root-end cavity was filled and the gutta-percha cone was removed after complete setting of the materials. The specimens were placed in an Instron machine with the root-end filling turned downwards. The push-out shaft was inserted in the space previously occupied by the gutta-percha cone and push out testing was performed at a crosshead speed of 1.0 mm/min. There was no statistically significant difference in resistance to push out by the materials tested (p > 0.01. MTA Angelus and ProRoot MTA showed predominantly mixed failure while Biodentine exhibited mixed and cohesive failures. The tricalcium silicate-based root-end filling materials showed similar bond strength retrograde cavity.

Push-out bond strength of different tricalcium silicate-based filling materials to root dentin.

Science.gov (United States)

Stefaneli Marques, Jorge Henrique; Silva-Sousa, Yara Teresinha Corrêa; Rached-Júnior, Fuad Jacob Abi; Macedo, Luciana Martins Domingues de; Mazzi-Chaves, Jardel Francisco; Camilleri, Josette; Sousa-Neto, Manoel Damião

2018-03-08

The aim of this study was to evaluate the bond strength of different triccalcium silicate cements to retrograde cavity using a push out test. Thirty maxillary central incisors were shaped using #80 hand files and sectioned transversally. Root slices were obtained from the apical 4 mm after eliminating the apical extremity. The specimens were embedded in acrylic resin and positioned at 45° to the horizontal plane for preparation of root-end cavities with a diamond ultrasonic retrotip. The samples were divided into three groups according to the root-end filling material (n = 10): MTA Angelus, ProRoot MTA and Biodentine. A gutta-percha cone (#80) was tugged-back at the limit between the canal and the root-end cavity. The root-end cavity was filled and the gutta-percha cone was removed after complete setting of the materials. The specimens were placed in an Instron machine with the root-end filling turned downwards. The push-out shaft was inserted in the space previously occupied by the gutta-percha cone and push out testing was performed at a crosshead speed of 1.0 mm/min. There was no statistically significant difference in resistance to push out by the materials tested (p > 0.01). MTA Angelus and ProRoot MTA showed predominantly mixed failure while Biodentine exhibited mixed and cohesive failures. The tricalcium silicate-based root-end filling materials showed similar bond strength retrograde cavity.

Comparison of the effects of an eight-week push-up program using stable versus unstable surfaces.

Science.gov (United States)

Chulvi-Medrano, Iván; Martínez-Ballester, Esteban; Masiá-Tortosa, Laura

2012-12-01

Recently, the trend among physical training and rehabilitation professionals is the use of resistance exercise on unstable equipment in order to increase the effort of the agonist and stabilizing muscles. It is unknown if performing exercises on unstable surfaces provides a greater training stimulus as compared to training on a stable training surface. Therefore, the purpose of this research was to compare the effect that push-up training on stable and unstable surfaces had on strength performance in healthy young men. Thirty subjects with experience in resistance training participated in push-up training two days per week for eight weeks on one of three different surfaces: the floor (Tp), the T-Bow® (TBp) or the BOSU® (Bp). Strength, as measured by one repetition maximum (1-RM) and muscle endurance, as measured by number of pushups performed did not improve significantly (p>0.05) for any of the intervention groups. The addition of unstable surfaces in push-up training does not provide greater improvement in muscular strength and endurance than push up training performed on a stable surface in young men. 3b.

A sled push stimulus potentiates subsequent 20-m sprint performance.

Science.gov (United States)

Seitz, Laurent B; Mina, Minas A; Haff, G Gregory

2017-08-01

The objective of this study was to examine the potentiating effects of performing a single sprint-style sled push on subsequent unresisted 20m sprint performance. Randomized crossover design. Following a familiarization session, twenty rugby league players performed maximal unresisted 20m sprints before and 15s, 4, 8 and 12min after a single sled push stimulus loaded with either 75 or 125% body mass. The two sled push conditions were performed in a randomized order over a one-week period. The fastest sprint time recorded before each sled push was compared to that recorded at each time point after to determine the post-activation potentiation (PAP) effect. After the 75% body mass sled push, sprint time was 0.26±1.03% slower at the 15s time point (effect size [ES]=0.07) but faster at the 4 (-0.95±2.00%; ES=-0.22), 8 (-1.80±1.43%; ES=-0.42) and 12 (-1.54±1.54%; ES=-0.36)min time points. Sprint time was slower at all the time points after the 125% body mass sled (1.36±2.36%-2.59±2.90%; ESs=0.34-0.64). Twenty-meter sprint performance is potentiated 4-12min following a sled push loaded with 75% body mass while it is impaired after a 125% body mass sled. These results are of great importance for coaches seeking to potentiate sprint performance with the sled push exercise. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Implementation of Push Recovery Strategy Using Triple Linear Inverted Pendulum Model in “T-FloW” Humanoid Robot

Science.gov (United States)

Dimas Pristovani, R.; Raden Sanggar, D.; Dadet, Pramadihanto.

2018-04-01

Push recovery is one of humanbehaviorwhich is a strategy to defend the body from anexternal force in any environment. This paper describes push recovery strategy which usesMIMO decoupled control system method. The dynamics system uses aquasi-dynamic system based on triple linear inverted pendulum model (TLIPM). The analysis of TLIPMuses zero moment point (ZMP) calculation from ZMP simplification in last research. By using this simplification of dynamics system, the control design can be simplified into 3 serial SISOwith known and uncertain disturbance models in each inverted pendulum. Each pendulum has different plan to damp the external force effect. In this experiment, PID controller (closed- loop)is used to arrange the damp characteristic.The experiment result shows thatwhen using push recovery control strategy (closed-loop control) is about 85.71% whilewithout using push recovery control strategy (open-loop control) it is about 28.57%.

Effect of spontaneous pushing versus Valsalva pushing in the second stage of labour on mother and fetus: a systematic review of randomised trials

NARCIS (Netherlands)

Prins, M. [=Marianne; Boxem, J.; Lucas, C.; Hutton, E.

2011-01-01

To critically evaluate any benefit or harm for the mother and her baby of Valsalva pushing versus spontaneous pushing in the second stage of labour. Electronic databases from MEDLINE, EMBASE, CINAHL, and the Cochrane Central Register of Controlled Trials were systematically searched (last search May

Variations of the ionization push frequency in the ASK-1 chamber

International Nuclear Information System (INIS)

Krivoshapkin, P.A.; Mamrukova, V.P.; Skripin, G.V.; Shafer, G.V.

1997-01-01

The data on frequency push in the ASK-1 chamber at the Yakutsk station for 1954-1994 are analyzed. The observed eleven-year and half-year push variations are related to the solar activity. The narrowly directed galactic anisotropy with 6-8 h direction, coinciding with the direction of the helio-magnetosphere tail, formed by the solar system motion relative to stars is identified in a daily motion by sidereal time. The great barometric and temperature coefficients of the frequency pushes are obtained. This indicates the prevailing role of the nuclear-active particles in formation of pushes

Pushing Back against Push-In: ESOL Teacher Resistance and the Complexities of Coteaching

Science.gov (United States)

McClure, Greg; Cahnmann-Taylor, Melisa

2010-01-01

As U. S. school districts struggle to address persistent achievement gaps between increasing numbers of English language learners (ELLs) and their native-English-speaking counterparts, many districts are moving away from segregative models like pull-out to implement more collaborative approaches such as coteaching, or push-in. In contrast to…

[Methods of pushing at vaginal delivery and pelvi-perineal consequences. Review].

Science.gov (United States)

Ratier, N; Balenbois, E; Letouzey, V; Marès, P; de Tayrac, R

2015-03-01

The main objective of that review was to evaluate the pelvi-perineal consequences of the different methods of pushing at vaginal delivery. A review on PubMed, the Cochrane Library and EM-Premium was performed from 1984 to 2014. Among 29 manuscripts analysed, only nine randomised controlled trials (including one meta-analysis of three trials) comparing Valsalva and spontaneous pushing were selected. A 10 th study, secondary analysis of a randomized controlled trial comparing different methods of perineal protection (warm compresses, massage and manual protection), was also selected. Two trials have shown that spontaneous pushing reduces the risk of perineal tears, but studies were heterogeneous and discordant results do not allowed definitive conclusions. Results on the duration of the second stage of labour are conflicting. The method of pushing does not seem to affect the rate of episiotomy, instrumental delivery and cesarean section. Maternal satisfaction seems to be better after spontaneous pushing. It seems that there is no negative effect of spontaneous pushing on neonate well-being, and one study has shown a significant improvement of prenatal fetal parameters during the expulsive phase. According to current knowledge, both techniques of pushing during the expulsive phase at delivery seem comparable in terms of duration, risk of perineal tears and neonatal outcome. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Are pushing and pulling work-related risk factors for upper extremity symptoms? A systematic review of observational studies.

Science.gov (United States)

Hoozemans, M J M; Knelange, E B; Frings-Dresen, M H W; Veeger, H E J; Kuijer, P P F M

2014-11-01

Systematically review observational studies concerning the question whether workers that perform pushing/pulling activities have an increased risk for upper extremity symptoms as compared to workers that perform no pushing/pulling activities. A search in MEDLINE via PubMed and EMBASE was performed with work-related search terms combined with push/pushing/pull/pulling. Studies had to examine exposure to pushing/pulling in relation to upper extremity symptoms. Two authors performed the literature selection and assessment of the risk of bias in the studies independently. A best evidence synthesis was used to draw conclusions in terms of strong, moderate or conflicting/insufficient evidence. The search resulted in 4764 studies. Seven studies were included, with three of them of low risk of bias, in total including 8279 participants. A positive significant relationship with upper extremity symptoms was observed in all four prospective cohort studies with effect sizes varying between 1.5 and 4.9. Two out of the three remaining studies also reported a positive association with upper extremity symptoms. In addition, significant positive associations with neck/shoulder symptoms were found in two prospective cohort studies with effect sizes of 1.5 and 1.6, and with shoulder symptoms in one of two cross-sectional studies with an effect size of 2.1. There is strong evidence that pushing/pulling is related to upper extremity symptoms, specifically for shoulder symptoms. There is insufficient or conflicting evidence that pushing/pulling is related to (combinations of) upper arm, elbow, forearm, wrist or hand symptoms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Gender Inequality and Emigration: Push factor or Selection process?

OpenAIRE

Baudassé, Thierry; Bazillier, Rémi

2012-01-01

Our objective in this research is to provide empirical evidence relating to the linkages between gender equality and international emigration. Two theoretical hypotheses can be made for the purpose of analyzing such linkages. The fi rst is that gender inequality in origin countries could be a push factor for women. The second one is that gender inequality may create a \\gender bias" in the selection of migrants within a household or a community. An improvement of gender equality would then inc...

Medical and Non-Medical Factors Influencing Utilization of Delayed Pushing in the Second Stage

Science.gov (United States)

FREY, Heather A.; TUULI, Methodius G.; CORTEZ, Sarah; ODIBO, Anthony O.; ROEHL, Kimberly A.; SHANKS, Anthony L.; MACONES, George A.; CAHILL, Alison G.

2014-01-01

Objective To evaluate factors impacting selection to delayed pushing in the second stage of labor. Study design This case-control study was a secondary analysis of a large retrospective cohort study. Cases included women who delayed pushing for 60 minutes or more in the second stage of labor. Controls began pushing prior to 60 minutes from the time of diagnosis of complete dilation. Demographic, labor, and nonmedical factors were compared among cases and controls. Logistic regression modelling was used to identify factors independently associated with delayed pushing. Results We identified 471 women who delayed pushing and 4,819 controls. Nulliparity, maternal body mass index > 25, high fetal station at complete dilation, regional anesthesia use, and start of second stage during staffing shift change were independent factors associated with increased use of delayed pushing. On the other hand, black race and second stage management during night shift were associated with lower odds of employing delayed pushing. Delayed pushing was more commonly employed in nulliparous women, but 38.9% of multiparous women also delayed pushing. Conclusion We identified multiple factors associated with use of delayed pushing. This study helps to define current patterns of second stage labor management. PMID:23208765

Arterial cord blood lactate at birth correlates with duration of pushing efforts.

Science.gov (United States)

Dessolle, Lionel; Lebrec, Jeremie; Daraï, Emile

2010-01-01

To evaluate the impact of the duration of pushing efforts on arterial cord blood lactate values. This was a prospective observational study of 124 consecutive normal vaginal deliveries in a tertiary teaching hospital. Arterial cord blood lactate was determined immediately at birth with a test strip method. Univariate and multivariate analyses were performed to check for clinical determinants of lactate levels. The main measure was lactate according to the duration of pushing efforts. Arterial cord lactates increased significantly and were strongly correlated with the duration of pushing efforts, independent of gestational age and birthweight. Women pushing for more than 20 min had higher arterial cord blood lactates (4.9 +/- 1.4 vs. 3.3 +/- 1.16 mM, respectively) and a higher rate of lactates >6 mM (18 vs. 3%) than those pushing for less than 20 min. At normal delivery, arterial cord blood lactates increase significantly with the duration of pushing efforts. Pushing for more than 20 min is associated with an increased risk of metabolic acidosis in the neonate. Further studies are required to evaluate the clinical significance of these observations. 2009 S. Karger AG, Basel.

Restoration of Hyperspectral Push-Broom Scanner Data

DEFF Research Database (Denmark)

Larsen, Rasmus; Nielsen, Allan Aasbjerg; Conradsen, Knut

1997-01-01

Several effects combine to distort the multispectral data that are obtained from push-broom scanners. We develop an algorithm for restoration of such data, illustrated on images from the ROSIS scanner. In push-broom scanners variation between elements in the detector array results in a strong...... back into the original spectral space results in noise corrected variables. The noise components will now have been removed from the entire original data set by working on a smaller set of noise contaminated transformed variables only. The application of the above techniques results in a dramatic...

Integrated Food studies education and research:

DEFF Research Database (Denmark)

Hansen, Mette Weinreich; Hansen, Stine Rosenlund

2018-01-01

The research group Foodscapes Innovation and Networks has addressed integrated food studies issues in re-search and education since 2010. Based on experiences in the group, this paper aims at discussing the chal-lenges, learning outcomes and potentials for pushing an integrated thinking into rese......The research group Foodscapes Innovation and Networks has addressed integrated food studies issues in re-search and education since 2010. Based on experiences in the group, this paper aims at discussing the chal-lenges, learning outcomes and potentials for pushing an integrated thinking...... into research and education. It also addresses the challenges in integration when the methodological approaches and theoretical frameworks chosen are ontologically and epistemologically different. A discussion of the limitations of integration is thus also part of the paper. The conceptual framework...... of ontonorms (Mol, 2013) is suggested as a common point of departure for a further development of integration. This is suggested relevant due to the fact that it forces different traditions to reflect their own value-related basis and discuss implications of this approach in a broader sense. The common values...

Control of trunk motion following sudden stop perturbations during cart pushing.

Science.gov (United States)

Lee, Yun-Ju; Hoozemans, Marco J M; van Dieën, Jaap H

2011-01-04

External perturbations during pushing tasks have been suggested to be a risk factor for low-back symptoms. An experiment was designed to investigate whether self-induced and externally induced sudden stops while pushing a high inertia cart influence trunk motions, and how flexor and extensor muscles counteract these perturbations. Twelve healthy male participants pushed a 200 kg cart at shoulder height and hip height. Pushing while walking was compared to situations in which participants had to stop the cart suddenly (self-induced stop) or in which the wheels of the cart were unexpectedly blocked (externally induced stop). For the perturbed conditions, the peak values and the maximum changes from the reference condition (pushing while walking) of the external moment at L5/S1, trunk inclination and electromyographic amplitudes of trunk muscles were determined. In the self-induced stop, a voluntary trunk extension occurred. Initial responses in both stops consisted of flexor and extensor muscle cocontraction. In self-induced stops this was followed by sustained extensor activity. In the externally induced stops, an external extension moment caused a decrease in trunk inclination. The opposite directions of the internal moment and trunk motion in the externally induced stop while pushing at shoulder height may indicate insufficient active control of trunk posture. Consequently, sudden blocking of the wheels in pushing at shoulder height may put the low back at risk of mechanical injury. Copyright © 2010 Elsevier Ltd. All rights reserved.

Muscle Activation during Push-Ups with Different Suspension Training Systems

Directory of Open Access Journals (Sweden)

Joaquin Calatayud, Sebastien Borreani, Juan C. Colado, Fernando F Martín, Michael E. Rogers

2014-09-01

Full Text Available The purpose of this study was to analyze upper extremity and core muscle activation when performing push-ups with different suspension devices. Young fit male university students (n = 29 performed 3 push-ups each with 4 different suspension systems. Push-up speed was controlled using a metronome and testing order was randomized. Average amplitude of the electromyographic root mean square of Triceps Brachii, Upper Trapezius, Anterior Deltoid, Clavicular Pectoralis, Rectus Abdominis, Rectus Femoris, and Lumbar Erector Spinae was recorded. Electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC. Electromyographic data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Based upon global arithmetic mean of all muscles analyzed, the suspended push-up with a pulley system provided the greatest activity (37.76% of MVIC; p < 0.001. Individually, the suspended push-up with a pulley system also provided the greatest triceps brachii, upper trapezius, rectus femoris and erector lumbar spinae muscle activation. In contrast, more stable conditions seem more appropriate for pectoralis major and anterior deltoid muscles. Independent of the type of design, all suspension systems were especially effective training tools for reaching high levels of rectus abdominis activation.

Relationship between push phase and final race time in skeleton performance.

Science.gov (United States)

Zanoletti, Costanza; La Torre, Antonio; Merati, Giampiero; Rampinini, Ermanno; Impellizzeri, Franco M

2006-08-01

The aim of this study was to examine the relationship between push-time and final race time in skeleton participants during a series of major international competitions to determine the importance of the push phase in skeleton performance. Correlations were computed from the first and second heat split data measured during 24 men and 24 women skeleton competitions. Body mass, height, age, and years of experience of the first 30 men and women athletes of the skeleton, bobsleigh and luge 2003-2004 World Cup ranking were used for the comparison between sliding sports. Moderate but significant correlations (p push-time and final race time in men (r(mean) = 0.48) and women (r(mean) = 0.63). No correlations were found between changes in the individual push-time between the first and second heat with the corresponding changes in final race time. The bobsleigh sliders are heavier than the athletes of the other sliding disciplines. Luge athletes have more experience and are younger than bobsleigh and skeleton sliders. The results of this study suggest that a fast push phase is a prerequisite to success in competition and confirms that the selection of skeleton athletes based on the ability to accelerate to a maximum speed quickly could be valid. However, a good or improved push-time does not ensure a placement in the top finishing positions. On the basis of these results, we suggest that strength and power training is necessary to maintain a short push-time but additional physical training aimed to enhance the push phase might not reflect performance improvements. The recruitment of younger athletes and an increase of youthful competitive activity may be another effective way to reach international competitive results.

An Extra Push from Entrance-Channel Effects

International Nuclear Information System (INIS)

Grar, Nabila; Rowley, Neil

2006-01-01

The fusion probability for heavy symmetric systems is known to show certain very specific features. Apart from the large variance of the fusion barrier distribution, it is found that the energy at which the s-wave transmission is 0.5 is shifted to an energy significantly higher than the nominal (e.g. Bass) Coulomb barrier. This last feature is referred to in the literature as the 'extra push' effect. Many models have been devised to explain the origin of these findings. It is worth noting, however, that despite the extra push, the capture cross section is still greatly enhanced at the very lowest energies. This fact cannot be explained within the framework of macroscopic theories involving conditional saddle points or frictional forces. We have performed full coupled-channel calculations for heavy, symmetric systems treating correctly the long-range Coulomb excitations of the collective quadrupole- and octupole-phonon states in the target and projectile. The results obtained show that the extra push and the overall shape of the fusion probability are simply explained by these entrance-channel effects

Body pushing, prescription drugs and hospital admission.

Science.gov (United States)

Byard, Roger W; Kenneally, Michaela

2017-09-01

A 39-year-old man died of multi-organ failure complicating mixed drug toxicity that included methadone, oxazepam, oxycodone and nitrazepam. His past medical history involved alcohol and poly-substance abuse with chronic self-harm and suicidal ideation. There had been multiple hospital admissions for drug overdoses. At autopsy the most unusual finding was of two packages of 10 tablets each, wrapped in thin plastic film within the rectum. The insertion of drugs into body orifices and cavities has been termed body pushing to distinguish it from body packing where illicit drugs are wrapped and swallowed for transport and smuggling, and body stuffing where small amounts of loosely wrapped or unwrapped drugs are swallowed to conceal evidence from police. This case demonstrates that body pushing may not always involve illicit drugs or attempted concealment from police or customs officials. It appears that the drugs had been hidden to ensure an additional supply during the time of residence in hospital. The extent to which body pushing is currently being used by patients to smuggle drugs into secure medical facilities is yet to be determined.

Pushing nanoparticles of La0.7Sr0.3MnO3

International Nuclear Information System (INIS)

Ma, Y.-R.; Liou Yung; Yao, Y.-D.

2004-01-01

Pushing nanoparticles of La 0.7 Sr 0.3 MnO 3 (LSMO) on a native SiO 2 surface using atomic force microscopy (AFM) in the tapping mode is presented. The pushing is accompanied by a repulsive tip-sample interaction between the AFM tip and the LSMO nanoparticles and the physisorption of the LSMO on the SiO 2 surface. The AFM images show scratch artifacts on the surface, indicating that artificial scratches are strongly related to the pushing of the LSMO nanoparticles. A possible approach to pushing nanoparticles is proposed

33 CFR 164.76 - Towline and terminal gear for towing alongside and pushing ahead.

Science.gov (United States)

2010-07-01

... towing alongside and pushing ahead. 164.76 Section 164.76 Navigation and Navigable Waters COAST GUARD... Towline and terminal gear for towing alongside and pushing ahead. The owner, master, or operator of each vessel towing alongside or pushing ahead shall ensure that the face wires, spring lines, and push gear...

Manual handling: differences in perceived effort, success rate and kinematics between three different pushing techniques.

Science.gov (United States)

Varcin, Lynn; Claus, Andrew; van den Hoorn, Wolbert; Hodges, Paul

2015-01-01

This study examined the perceived effort, success rates and kinematics for three push strategies in a simulated lateral patient transfer (horizontal slide). Thirteen healthy subjects (four males) completed three repetition pushing loads of 6, 10 and 14 kg in random order; with a spontaneous push strategy, then with a straight-back bent-knees (squat) strategy and the preparatory pelvic movement ('rockback') strategy in random order. Perceived effort and kinematic parameters measured at the onset of movement and at maximum push excursion were compared between strategies and between loads with repeated measures ANOVA. The spontaneous and 'rockback' strategies achieved the pushing task with less perceived effort across all loads than the squat push (P pushing the 14 kg load using a squat strategy, which contrasted with 12/13 participants when the spontaneous strategy or the 'rockback' strategy was used. Forward movement of the pelvis and forward trunk inclination may be positively associated with lower perceived effort in the push task. Practitioner Summary: In a manual-handling task that simulated a lateral patient transfer (horizontal slide), perceived effort and success rates of three push strategies were compared. A straight-back bent-knees push (squat) strategy demonstrated greater perceived effort and lower success rates than a spontaneous push strategy, or a push strategy with preparatory 'rockback' pelvic movement.

Effects of Angle Variations in Suspension Push-up Exercise.

Science.gov (United States)

Gulmez, Irfan

2017-04-01

Gulmez, I. Effects of angle variations in suspension push-up exercise. J Strength Cond Res 31(4): 1017-1023, 2017-This study aimed to determine and compare the amount of loads on the TRX Suspension Trainer (TRX) straps and ground reaction forces at 4 different angles during TRX push-ups. Twenty-eight male (mean age, 24.1 ± 2.9 years; height, 179.4 ± 8.0 m; weight, 78.8 ± 9.8 kg) physical education and sports university students participated in this study. The subjects were tested at TRX angles (0, 15, 30, 45°) during the TRX push-ups. Force data were recorded by a force platform and load cells integrated into the TRX straps. The results show that as the TRX angle was reduced, the load applied to the TRX straps increased and simultaneously the load measured by the force platform decreased. This was true for both the elbow joint changing from flexion to extension and vice versa. When the TRX angle was set at 0° and subjects' elbows were at extension during TRX push-up, 50.4% of the subjects' body weight, and when the elbows were at flexion, 75.3% of the body weight was registered by the sensors on the TRX straps. The results of this study can be used in the calculation of the training load and volume (resistance training programming) during TRX push-up exercises at varying angles.

Global Models of Ridge-Push Force, Geoid, and Lithospheric Strength of Oceanic plates

Science.gov (United States)

Mahatsente, Rezene

2017-12-01

An understanding of the transmission of ridge-push related stresses in the interior of oceanic plates is important because ridge-push force is one of the principal forces driving plate motion. Here, I assess the transmission of ridge-push related stresses in oceanic plates by comparing the magnitude of the ridge-push force to the integrated strength of oceanic plates. The strength is determined based on plate cooling and rheological models. The strength analysis includes low-temperature plasticity (LTP) in the upper mantle and assumes a range of possible tectonic conditions and rheology in the plates. The ridge-push force has been derived from the thermal state of oceanic lithosphere, seafloor depth and crustal age data. The results of modeling show that the transmission of ridge-push related stresses in oceanic plates mainly depends on rheology and predominant tectonic conditions. If a lithosphere has dry rheology, the estimated strength is higher than the ridge-push force at all ages for compressional tectonics and at old ages (>75 Ma) for extension. Therefore, under such conditions, oceanic plates may not respond to ridge-push force by intraplate deformation. Instead, the plates may transmit the ridge-push related stress in their interior. For a wet rheology, however, the strength of young lithosphere (stress may dissipate in the interior of oceanic plates and diffuses by intraplate deformation. The state of stress within a plate depends on the balance of far-field and intraplate forces.

Positioning of microtubule organizing centers by cortical pushing and pulling forces

International Nuclear Information System (INIS)

Pavin, Nenad; Ma Rui; Jülicher, Frank; Laan, Liedewij; Dogterom, Marileen

2012-01-01

Positioning of microtubule (MT) organizing centers with respect to the confining geometry of cells depends on pushing and/or pulling forces generated by MTs that interact with the cell cortex (Dogterom et al 2005 Curr. Opin. Cell Biol. 17 67–74). How, in living cells, these forces lead to proper positioning is still largely an open question. Recently, it was shown by in vitro experiments using artificial microchambers that in a square geometry, MT asters center more reliably by a combination of pulling and pushing forces than by pushing forces alone (Laan et al 2012a Cell 148 502–14). These findings were explained by a physical description of aster mechanics that includes slipping of pushing MT ends along chamber boundaries. In this paper, we extend that theoretical work by studying the influence of the shape of the confining geometry on the positioning process. We find that pushing and pulling forces can have centering or off-centering behavior in different geometries. Pushing forces center in a one-dimensional and a square geometry, but lead to off-centering in a circle if slipping is sufficiently pronounced. Pulling forces, however, do not center in a one-dimensional geometry, but improve centering in a circle and a square. In an elongated stadium geometry, positioning along the short axis depends mainly on pulling forces, while positioning along the long axis depends mainly on pushing forces. Our theoretical results suggest that different positioning strategies could be used by different cell types. (paper)

Pushing Boundaries while Maintaining Stability

DEFF Research Database (Denmark)

Lippke, Lena; Wegener, Charlotte

at the same time. The exploration of transforming practices shows how disturbances in relation to the ‘normal’ practices are created and thus makes invisible conventions which are taken for granted visible. Thus, this paper addresses two types of invisibility: the unnoticed boundary-pushing practices...

Modelling endurance and resumption times for repetitive one-hand pushing.

Science.gov (United States)

Rose, Linda M; Beauchemin, Catherine A A; Neumann, W Patrick

2018-07-01

This study's objective was to develop models of endurance time (ET), as a function of load level (LL), and of resumption time (RT) after loading as a function of both LL and loading time (LT) for repeated loadings. Ten male participants with experience in construction work each performed 15 different one-handed repetaed pushing tasks at shoulder height with varied exerted force and duration. These data were used to create regression models predicting ET and RT. It is concluded that power law relationships are most appropriate to use when modelling ET and RT. While the data the equations are based on are limited regarding number of participants, gender, postures, magnitude and type of exerted force, the paper suggests how this kind of modelling can be used in job design and in further research. Practitioner Summary: Adequate muscular recovery during work-shifts is important to create sustainable jobs. This paper describes mathematical modelling and presents models for endurance times and resumption times (an aspect of recovery need), based on data from an empirical study. The models can be used to help manage fatigue levels in job design.

Oblique abdominal muscle activity in response to external perturbations when pushing a cart.

Science.gov (United States)

Lee, Yun-Ju; Hoozemans, Marco J M; van Dieën, Jaap H

2010-05-07

Cyclic activation of the external and internal oblique muscles contributes to twisting moments during normal gait. During pushing while walking, it is not well understood how these muscles respond to presence of predictable (cyclic push-off forces) and unpredictable (external) perturbations that occur in pushing tasks. We hypothesized that the predictable perturbations due to the cyclic push-off forces would be associated with cyclic muscle activity, while external perturbations would be counteracted by cocontraction of the oblique abdominal muscles. Eight healthy male subjects pushed at two target forces and two handle heights in a static condition and while walking without and with external perturbations. For all pushing tasks, the median, the static (10th percentile) and the peak levels (90th percentile) of the electromyographic amplitudes were determined. Linear models with oblique abdominal EMGs and trunk angles as input were fit to the twisting moments, to estimate trunk stiffness. There was no significant difference between the static EMG levels in pushing while walking compared to the peak levels in pushing while standing. When pushing while walking, the additional dynamic activity was associated with the twisting moments, which were actively modulated by the pairs of oblique muscles as in normal gait. The median and static levels of trunk muscle activity and estimated trunk stiffness were significantly higher when perturbations occurred than without perturbations. The increase baseline of muscle activity indicated cocontraction of the antagonistic muscle pairs. Furthermore, this cocontraction resulted in an increased trunk stiffness around the longitudinal axis. Copyright 2010 Elsevier Ltd. All rights reserved.

49 CFR 220.49 - Radio communication used in shoving, backing or pushing movements.

Science.gov (United States)

2010-10-01

... pushing movements. 220.49 Section 220.49 Transportation Other Regulations Relating to Transportation... Wireless Communication Procedures § 220.49 Radio communication used in shoving, backing or pushing movements. When radio communication is used in connection with the shoving, backing or pushing of a train...

Push for the Second Screen

DEFF Research Database (Denmark)

Sørensen, Jannick Kirk; Sørensen, Lene Tolstrup

Users’ perception of the relation between the TV screen and a secondary screen (e.g. smartphone or tablet) is examined empirically in a pilot project through a low-fi prototype and interviews. Early observations indicate that the user value/acceptance of push-messages delivered to the second screen...

Force direction in pushing and pulling and Musculo-Skeletal load

NARCIS (Netherlands)

Looze, M.P. de; Kuijer, P.P.F.M.

1999-01-01

In pushing and pulling wheeled objects, the effect of the exerted force on local musculo-skeletal loads depends on the direction of force exertion. Several questions about the direction of force exertion in pushing and pulling, the effects of handle height and force level on force direction, and the

Coordination of push-off and collision determine the mechanical work of step-to-step transitions when isolated from human walking.

Science.gov (United States)

Soo, Caroline H; Donelan, J Maxwell

2012-02-01

In human walking, each transition to a new stance limb requires redirection of the center of mass (COM) velocity from one inverted pendulum arc to the next. While this can be accomplished with either negative collision work by the leading limb, positive push-off work by the trailing limb, or some combination of the two, physics-based models of step-to-step transitions predict that total positive work is minimized when the push-off and collision work are equal in magnitude. Here, we tested the importance of the coordination of push-off and collision work in determining transition work using ankle and knee joint braces to limit the ability of a leg to perform positive work on the body. To isolate transitions from other contributors to walking mechanics, participants were instructed to rock back and forth from one leg to the other, restricting motion to the sagittal plane and eliminating the need to swing the legs. We found that reduced push-off work increased the collision work required to complete the redirection of the COM velocity during each transition. A greater amount of total mechanical work was required when rocking departed from the predicted optimal coordination of step-to-step transitions, in which push-off and collision work are equal in magnitude. Our finding that transition work increases if one or both legs do not push-off with the optimal coordination may help explain the elevated metabolic cost of pathological gait irrespective of etiology. Copyright © 2011 Elsevier B.V. All rights reserved.

On Reducing Delay in Mesh-Based P2P Streaming: A Mesh-Push Approach

Science.gov (United States)

Liu, Zheng; Xue, Kaiping; Hong, Peilin

The peer-assisted streaming paradigm has been widely employed to distribute live video data on the internet recently. In general, the mesh-based pull approach is more robust and efficient than the tree-based push approach. However, pull protocol brings about longer streaming delay, which is caused by the handshaking process of advertising buffer map message, sending request message and scheduling of the data block. In this paper, we propose a new approach, mesh-push, to address this issue. Different from the traditional pull approach, mesh-push implements block scheduling algorithm at sender side, where the block transmission is initiated by the sender rather than by the receiver. We first formulate the optimal upload bandwidth utilization problem, then present the mesh-push approach, in which a token protocol is designed to avoid block redundancy; a min-cost flow model is employed to derive the optimal scheduling for the push peer; and a push peer selection algorithm is introduced to reduce control overhead. Finally, we evaluate mesh-push through simulation, the results of which show mesh-push outperforms the pull scheduling in streaming delay, and achieves comparable delivery ratio at the same time.

Control of vertical posture while standing on a sliding board and pushing an object.

Science.gov (United States)

Lee, Yun-Ju; Chen, Bing; Liang, Jing-Nong; Aruin, Alexander S

2018-03-01

Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that induces translational perturbation). Thirteen healthy young participants were instructed to push a handle with both hands while standing on a sliding board that was either free to move in the anterior-posterior direction or stationary. Electromyographic activity (EMG) of trunk and lower extremity muscles, center of pressure (COP) displacements, and the forces exerted by the hand were recorded and analyzed during the APA and CPA phases. When the sliding board was free to move during pushing (translation perturbation), onsets of activity of ventral leg muscles and COP displacement were delayed as compared to pushing when standing on a stationary board. Moreover, magnitudes of shank muscle activity and the COP displacement were decreased. When pushing heavier weight, magnitudes of muscle activity, COP displacement, and pushing force increased. The magnitude of activity of the shank muscles during the APA and CPA phases in conditions with translational perturbation varied with the magnitude of the pushing weight. The outcome of the study suggests that the central nervous system prioritizes the pushing task while attenuates the source of additional perturbation induced by translation perturbation. These results could be used in the development of balance re-training paradigms involving pushing weight while standing on a sliding surface.

Attentional Push: Augmenting Salience with Shared Attention Modeling

OpenAIRE

Gorji, Siavash; Clark, James J.

2016-01-01

We present a novel visual attention tracking technique based on Shared Attention modeling. Our proposed method models the viewer as a participant in the activity occurring in the scene. We go beyond image salience and instead of only computing the power of an image region to pull attention to it, we also consider the strength with which other regions of the image push attention to the region in question. We use the term Attentional Push to refer to the power of image regions to direct and man...

Quantifying muscle patterns and spine load during various forms of the push-up.

Science.gov (United States)

Freeman, Stephanie; Karpowicz, Amy; Gray, John; McGill, Stuart

2006-03-01

This study was conducted to quantify the normalized amplitudes of the abdominal wall and back extensor musculature during a variety of push-up styles. We also sought to quantify their impact on spinal loading by calculating spinal compression and torque generation in the L4-5 area. Ten university-age participants, nine males and one female, in good to excellent condition, volunteered to participate in this study. All participants were requested to perform a maximum of 12 different push-up exercises, three trials per exercise. Surface electromyographic data (EMG) were collected bilaterally on rectus abdominis, external oblique, internal oblique, latissimus dorsi, and erector spinae muscles, and unilaterally (right side) on pectoralis major, triceps brachii, biceps brachii, and anterior deltoid muscles. Spine kinetics were obtained using an anatomically detailed model of the torso/spine. This study revealed that more dynamic push-ups (i.e., ballistic, with hand movement) required more muscle activation and higher spine load, whereas placing labile balls under the hands only resulted in modest increases in spine load. Right rectus abdominis (RA) activation was significantly higher than left RA activation during the left hand forward push-up and vice versa for the right hand forward push-up (P push-ups (P push-up resulted in the highest spine compression. Skilled participants showed greater synchronicity with peak muscle activation (plyometric type of contractions) during ballistic push-ups. These data will help guide exercise selection for individuals with differing training objectives and injury history.

Push-pull optical pumping of pure superposition states

International Nuclear Information System (INIS)

Jau, Y.-Y.; Miron, E.; Post, A.B.; Kuzma, N.N.; Happer, W.

2004-01-01

A new optical pumping method, 'push-pull pumping', can produce very nearly pure, coherent superposition states between the initial and the final sublevels of the important field-independent 0-0 clock resonance of alkali-metal atoms. The key requirement for push-pull pumping is the use of D1 resonant light which alternates between left and right circular polarization at the Bohr frequency of the state. The new pumping method works for a wide range of conditions, including atomic beams with almost no collisions, and atoms in buffer gases with pressures of many atmospheres

14 mrad Extraction Line Optics for Push-Pull

International Nuclear Information System (INIS)

Nosochkov, Y.; Moffeit, K.; Seryi, A.; Morse, W.; Parker, B.

2007-01-01

The ILC design is based on a single Interaction Region (IR) with 14 mrad crossing angle and two detectors in the 'push-pull' configuration, where the detectors can alternately occupy the Interaction Point (IP). Consequently, the IR optics must be compatible with different size detectors designed for different distance L* between the IP and the nearest quadrupole. This paper presents the push-pull optics for the ILC extraction line compatible with L*= 3.5 m to 4.5 m, and the simulation results of extraction beam loss at 500 GeV CM with detector solenoid

Comparison of delayed versus immediate pushing during second stage of labor for nulliparous women with epidural anesthesia.

Science.gov (United States)

Gillesby, Erica; Burns, Suzan; Dempsey, Amy; Kirby, Shirley; Mogensen, Kami; Naylor, Kelly; Petrella, Joann; Vanicelli, Rebecca; Whelan, Breon

2010-01-01

To determine if the use of delayed pushing after the onset of the second stage of labor decreases the time of active pushing and decreases maternal fatigue. Randomized clinical trial. Labor and delivery unit of a not-for-profit community hospital. Convenience sample of nulliparous laboring women with epidural anesthesia. Immediate or delayed pushing (2 hours) during the second stage of labor at the time of complete cervical dilatation. The length of pushing, total length of the second stage, and maternal fatigue. A total of 77 women were studied (immediate pushing group=39; delayed pushing=38). The immediate pushing group averaged 94 (± 57) minutes in active pushing, while the delayed pushing group averaged 68 (± 46) minutes, a statistically significant difference (p=.04). No significant differences were found in fatigue scores between the immediate and delayed pushing groups (p>.05). We found that by delaying the onset of active pushing for 2 hours after the beginning of the second stage of labor, the time that nulliparous women with epidural anesthesia spent in active pushing was significantly decreased by 27%. Although the delayed pushing group rested for up to 2 hours, the total time in the second stage of labor averaged only 59 minutes longer than the immediate pushing group. © 2010 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

Predicting Bobsled Pushing Ability from Various Combine Testing Events.

Science.gov (United States)

Tomasevicz, Curtis L; Ransone, Jack W; Bach, Christopher W

2018-03-12

The requisite combination of speed, power, and strength necessary for a bobsled push athlete coupled with the difficulty in directly measuring pushing ability makes selecting effective push crews challenging. Current practices by USA Bobsled and Skeleton (USABS) utilize field combine testing to assess and identify specifically selected performance variables in an attempt to best predict push performance abilities. Combine data consisting of 11 physical performance variables were collected from 75 subjects across two winter Olympic qualification years (2009 and 2013). These variables were sprints of 15-, 30-, and 60 m, a flying 30 m sprint, a standing broad jump, a shot toss, squat, power clean, body mass, and dry-land brake and side bobsled pushes. Discriminant Analysis (DA) in addition to Principle Component Analysis (PCA) was used to investigate two cases (Case 1: Olympians vs. non-Olympians; Case 2: National Team vs. non-National Team). Using these 11 variables, DA led to a classification rule that proved capable of identifying Olympians from non-Olympians and National Team members from non-National Team members with 9.33% and 14.67% misclassification rates, respectively. The PCA was used to find similar test variables within the combine that provided redundant or useless data. After eliminating the unnecessary variables, DA on the new combinations showed that 8 (Case 1) and 20 (Case 2) other combinations with fewer performance variables yielded misclassification rates as low as 6.67% and 13.33% respectively. Utilizing fewer performance variables can allow governing bodies in many other sports to create more appropriate combine testing that maximize accuracy, while minimizing irrelevant and redundant strategies.

Range of Motion of the Ankle According to Pushing Force, Gender and Knee Position.

Science.gov (United States)

Cho, Kang Hee; Jeon, Yumi; Lee, Hyunkeun

2016-04-01

To investigate the difference of range of motion (ROM) of ankle according to pushing force, gender and knee position. One hundred and twenty-eight healthy adults (55 men, 73 women) between the ages of 20 and 51, were included in the study. One examiner measured the passive range of motion (PROM) of ankle by Dualer IQ Inclinometers and Commander Muscle Testing. ROM of ankle dorsiflexion (DF) and plantarflexion (PF) according to change of pushing force and knee position were measured at prone position. There was significant correlation between ROM and pushing force, the more pushing force leads the more ROM at ankle DF and ankle PF. Knee flexion of 90° position showed low PF angle and high ankle DF angle, as compared to the at neutral position of knee joint. ROM of ankle DF for female was greater than for male, with no significant difference. ROM of ankle PF for female was greater than male regardless of the pushing force. To our knowledge, this is the first study to assess the relationship between pushing force and ROM of ankle joint. There was significant correlation between ROM of ankle and pushing force. ROM of ankle PF for female estimated greater than male regardless of the pushing force and the number of measurement. The ROM of the ankle is measured differently according to the knee joint position. Pushing force, gender and knee joint position are required to be considered when measuring the ROM of ankle joint.

The Effect of Variation of Plyometric Push-Ups on Force-Application Kinetics and Perception of Intensity.

Science.gov (United States)

Dhahbi, Wissem; Chaouachi, Anis; Dhahbi, Anis Ben; Cochrane, Jodie; Chèze, Laurence; Burnett, Angus; Chamari, Karim

2017-02-01

To examine differences between ground-reaction-force (GRF)-based parameters collected from 5 types of plyometric push-ups. Between-trials reliability and the relationships between parameters were also assessed. Thirty-seven highly active commando soldiers performed 3 trials of 5 variations of the plyometric push-up in a counterbalanced order: standard countermovement push-up (SCPu), standard squat push-up (SSPu), kneeling countermovement push-up (KCPu), kneeling squat push-up (KSPu), and drop-fall push-up (DFPu). Vertical GRF was measured during these exercises using a portable Kistler force plate. The GRF applied by the hands in the starting position (initial force supported), peak GRF and rate of force development during takeoff, flight time, impact force, and rate of force development impact on landing were determined. During standard-position exercises (SCPu and SSPu) the initial force supported and impact force were higher (P push-up exercises ([CMP] SCPu, KCPu, and DFPu) than squat push-up exercises ([SP] SSPu and KSPu). Furthermore, the flight time was greater (P push-up exercises and train athletes' muscle power by correctly interpreting GRF-based parameters. However, caution is required as some parameters had marginal absolute reliability.

Failure conditions from push-out tests of a steel-concrete joint: experimental results

Czech Academy of Sciences Publication Activity Database

Helincks, P.; De Corte, W.; Klusák, Jan; Seitl, Stanislav; Boel, V.; De Schutter, G.

488-489, - (2012), s. 714-717 ISSN 1013-9826. [International Conference on Fracture and Damage Mechanics - FDM 2011 /10./. Dubrovník, 19.09.2011-21.09.2011] R&D Projects: GA ČR GAP108/10/2049 Institutional research plan: CEZ:AV0Z20410507 Keywords : steel-concrete joint * push-out test * shear bond strength Subject RIV: JL - Materials Fatigue, Friction Mechanics

Reduction of discomfort in pushing an industrial trolley using ergonomics

Science.gov (United States)

Kumar, M. Wilson; Vijay, S. J.; Vasudev, K. L.; Darius Gnanaraj, S.

2017-11-01

Poor design of industrial trolleys lead to more compressive stress on the low back of industrial workers. The research work reported in this paper recommends a handle height of an industrial trolley for use by the local population, which reduces the compressive stress on the low back. Experiments were conducted in a laboratory on five subjects of varying stature 165, 173, 174, 175 and 182 cm, with five different handle heights 90, 95, 100, 105 and 110 cm. A four wheeled trolley has been used to conduct the experiments. Caster wheels diameters of 100, 125 and 150 mm made of polyurethane were used. It is found that a handle height of 110 cm allows the users to exert minimum force during the initial pushing. A biomechanical model was employed to calculate the compressive force experienced by L5/S1 disc and it is found that the compressive load will be the least when the handle height is 110 cm. Optimization of handle height using Genetic Algorithm approach, Heart rate analysis and EMG analysis confirm that a handle height of 110 cm and a wheel diameter of 150 mm will reduce the discomfort of industry workers pushing trolleys.

Effects of asymmetrical stance and movement on body rotation in pushing.

Science.gov (United States)

Lee, Yun-Ju; Aruin, Alexander S

2015-01-21

Pushing objects in the presence of body asymmetries could increase the risk of back injury. Furthermore, when the object is heavy, it could exacerbate the effects induced by asymmetrical posture. We investigated how the use of asymmetrical posture and/or upper extremity movement affect vertical torque (Tz) and center of pressure (COP) displacement during pushing. Ten healthy volunteers were instructed to push objects of three different weights using two hands (symmetrical hand use) or one hand (asymmetrical hand use) while standing in symmetrical or asymmetrical foot-positions. The peak values of Tz and COP displacement in the medial-lateral direction (COPML) were analyzed. In cases of isolated asymmetry, changes in the Tz were mainly linked with effects of hand-use whereas effects of foot-position dominated changes in the COPML displacement. In cases of a combined asymmetry, the magnitudes of both Tz and COPML were additive when asymmetrical hand-use and foot-position induced the rotation of the lower and upper body in the same direction or subtractive when asymmetries resulted in the rotation of the body segments in the opposite directions. Moreover, larger Tz and COP displacements were seen when pushing the heavy weight. The results point out the importance of using Tz and COPML to describe the isolated or combined effects of asymmetrical upper extremity movement and asymmetrical posture on body rotation during pushing. Furthermore, it suggests that a proper combination of unilateral arm movement and foot placements could help to reduce body rotation even when pushing heavy objects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Technology and trend management at the interface of technology push and market pull

DEFF Research Database (Denmark)

Maier, Maximilian; Hofmann, Maximilian; Brem, Alexander

2016-01-01

Technology push and market pull innovation strategies are playing an important role for the effective management of ideas, technologies, and trends. The coexistence of these two approaches led to many debates and the focus switched several times from putting more effort into technology push aspects...... to fostering market pull approaches in the last decades. Still, there is no in-depth exploration of the interface of technology push and market pull and only few conceptual models are dealing with the connection between technology push and market pull in particular. Therefore, this study puts an exploratory...... focus on the innovation management processes of a global outdoor manufacturer with a special emphasis on the interface between technology push and market pull. From the case findings and our literature we conceptualise a non-linear innovation model that systematically integrates market pull...

The defence technique in Tai Chi Push Hands: a case study.

Science.gov (United States)

Chen, Hui-Chuan; Cheng, Kuang-You B; Liu, Yu-Jen; Chiu, Hung-Ta; Cheng, Kuang-Yu

2010-12-01

Developed from traditional Chinese martial arts, Tai Chi exercise includes different forms and interactive Push Hands but biomechanical analyses have focused on the former only. To analyse the techniques of Push Hands, an experienced master was asked to defend pushing by four opponents. Movements were videotaped and digitized using a motion analysis system. Surface electrodes were used to record the electromyographic activity of ten muscle groups. Two force plates were used to measure the ground reaction force on each foot. Inexperienced individuals performed the same procedure to serve as the control group. The results indicate that the master adopted a postural adjustment to maintain balance. A clear shift of body weight from the front to the rear foot and mediolateral displacement of the centre of gravity was observed. Low electromyographic activity was observed in the upper body muscle groups, while high electromyographic activity was observed in the right rectus femoris and very high activity in the left rectus femoris during the defence. All inexperienced participants lost their balance in resisting pushing. It is concluded that the Tai Chi defensive technique includes a subtle postural adjustment that slightly changes the pushing force direction, and allows the rear leg to resist the incoming force.

Optical micromanipulation of active cells with minimal perturbations: direct and indirect pushing.

Science.gov (United States)

Wang, Chenlu; Chowdhury, Sagar; Gupta, Satyandra K; Losert, Wolfgang

2013-04-01

The challenge to wide application of optical tweezers in biological micromanipulation is the photodamage caused by high-intensity laser exposure to the manipulated living systems. While direct exposure to infrared lasers is less likely to kill cells, it can affect cell behavior and signaling. Pushing cells with optically trapped objects has been introduced as a less invasive alternative, but the technique includes some exposure of the biological object to parts of the optical tweezer beam. To keep the cells farther away from the laser, we introduce an indirect pushing-based technique for noninvasive manipulation of sensitive cells. We compare how cells respond to three manipulation approaches: direct manipulation, pushing, and indirect pushing. We find that indirect manipulation techniques lessen the impact of manipulation on cell behavior. Cell survival increases, as does the ability of cells to maintain shape and wiggle. Our experiments also demonstrate that indirect pushing allows cell-cell contacts to be formed in a controllable way, while retaining the ability of cells to change shape and move.

An older worker's decision to "push or protect self" following a work-related injury.

Science.gov (United States)

Stikeleather, Jill

2004-01-01

This study highlights the return-to-work experience of older workers on worker's compensation as there is a dearth of research in this area. Qualitative research methods delineated the experience of four older workers who had sustained work-related musculoskeletal injuries. "Push or Protect Self" emerged as the core category with three themes, including the level of employer support and degree of flexibility in work; continued health problems; and financial distress. These themes influenced each worker's decision to either "push self" to meet their pre-injury work demands, or "protect self" and accept a job post-injury that was less physically demanding, but was at a lower pay level. The four workers sustained financial difficulties subsequent to being off work, and reported continued health problems related to their injuries after being discharged from the worker's compensation system. Degree of employer support in providing flexibility in work demands varied, where low support and inflexibility in job tasks contributed to difficulty in returning to work or in sustaining the work demands of the job.

Push and pull strategies: applications for health care marketing.

Science.gov (United States)

Kingsley, B R

1987-08-01

As health care markets mature and expand, strategies available in other industries become useful. This article examines how traditional push-pull strategies apply to health care. Marketers using a push strategy recognize that the sale of their services or goods is dependent upon the endorsement of a middleman and promote their product through the middleman. Those using a pull strategy market directly to the consumer. In this article, the author outlines the advantages and disadvantages of using each strategy.

Stroller running: Energetic and kinematic changes across pushing methods.

Science.gov (United States)

Alcantara, Ryan S; Wall-Scheffler, Cara M

2017-01-01

Running with a stroller provides an opportunity for parents to exercise near their child and counteract health declines experienced during early parenthood. Understanding biomechanical and physiological changes that occur when stroller running is needed to evaluate its health impact, yet the effects of stroller running have not been clearly presented. Here, three commonly used stroller pushing methods were investigated to detect potential changes in energetic cost and lower-limb kinematics. Sixteen individuals (M/F: 10/6) ran at self-selected speeds for 800m under three stroller conditions (2-Hands, 1-Hand, and Push/Chase) and an independent running control. A significant decrease in speed (p = 0.001) and stride length (ppushing method had a significant effect on speed (p = 0.001) and stride length (ppushing technique influences stroller running speed and kinematics. These findings suggest specific fitness effects may be achieved through the implementation of different pushing methods.

Maternal and Neonatal Outcomes With Early Compared With Delayed Pushing Among Nulliparous Women.

Science.gov (United States)

Yee, Lynn M; Sandoval, Grecio; Bailit, Jennifer; Reddy, Uma M; Wapner, Ronald J; Varner, Michael W; Caritis, Steve N; Prasad, Mona; Tita, Alan T N; Saade, George; Sorokin, Yoram; Rouse, Dwight J; Blackwell, Sean C; Tolosa, Jorge E

2016-11-01

To describe factors associated with delayed pushing and evaluate the relationship between delayed pushing and perinatal outcomes in nulliparous women with singleton term gestations. This was a secondary analysis of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Assessment of Perinatal Excellence cohort of 115,502 women and their neonates born in 25 U.S. hospitals from 2008 to 2011. Nulliparous women with singleton, cephalic, nonanomalous term births who achieved 10-cm cervical dilation were included. Women in whom pushing was delayed by 60 minutes or greater (delayed group) were compared with those who initiated pushing within 30 minutes (early group). Multivariable regression analyses were used to assess the independent association of delayed pushing with mode of delivery, length of the second stage, and other maternal and perinatal outcomes (significance defined as Ppushing was delayed in 18.4% (n=3,870). Women who were older, privately insured, or non-Hispanic white as well as those who had induction or augmentation of labor, diabetes, or epidural analgesia were more likely to have delayed pushing. Delayed pushing was more common when the second stage began during daytime hours or in hospitals with dedicated 24-hour obstetric anesthesia, although differences were small. After adjusting for differences in baseline and labor characteristics including center, women in the delayed group had longer mean durations of the second stage (191 compared with 84 minutes, Ppushing (86 compared with 76 minutes, Ppushing was associated with greater rates of cesarean delivery (11.2% compared with 5.1%; adjusted odds ratio [OR] 1.86, 95% confidence interval [CI] 1.63-2.12), operative vaginal delivery (adjusted OR 1.26, 95% CI 1.14-1.40), postpartum hemorrhage (adjusted OR 1.43, 95% CI 1.05-1.95), and blood transfusion (adjusted OR 1.51, 95% CI 1.04-2.17). Delayed pushing was not associated with increased odds of adverse neonatal outcomes

Effects of Different Relative Loads on Power Performance During the Ballistic Push-up.

Science.gov (United States)

Wang, Ran; Hoffman, Jay R; Sadres, Eliahu; Bartolomei, Sandro; Muddle, Tyler W D; Fukuda, David H; Stout, Jeffrey R

2017-12-01

Wang, R, Hoffman, JR, Sadres, E, Bartolomei, S, Muddle, TWD, Fukuda, DH, and Stout, JR. Effects of different relative loads on power performance during the ballistic push-up. J Strength Cond Res 31(12): 3411-3416, 2017-The purpose of this investigation was to examine the effect of load on force and power performance during a ballistic push-up. Sixty (24.5 ± 4.3 years, 1.75 ± 0.07 m, and 80.8 ± 13.5 kg) recreationally active men who participated in this investigation completed all testing and were included in the data analysis. All participants were required to perform a 1 repetition maximum bench press, and ballistic push-ups without external load (T1), with 10% (T2) and 20% (T3) of their body mass. Ballistic push-ups during T2 and T3 were performed using a weight loaded vest. Peak and mean force, power, as well as net impulse and flight time were determined for each ballistic push-up. Peak and mean force were both significantly greater (p ballistic push-up, regardless of the participants' level of strength.

Optimal regenerative braking with a push-belt CVT: an experimental study

NARCIS (Netherlands)

Berkel, van K.; Hofman, T.; Vroemen, B.G.; Steinbuch, M.

2010-01-01

This paper describes the approach and the results of efficiency experiments on a push-belt Continuously Variable Transmission (CVT) in a new hybrid drive train. The hybrid drive train uses the push-belt CVT to charge a flywheel, with the kinetic energy of the vehicle during regenerative braking and

Optimal regenerative braking with a push-belt CVT : an experimental study

NARCIS (Netherlands)

van Berkel, K.; Hofman, T.; Vroemen, B.; Steinbuch, M.

2010-01-01

This paper describes the approach and the results of efficiency experiments on a push-belt Continuously Variable Transmission (CVT) in a new hybrid drive train. The hybrid drive train uses the push-belt CVT to “charge” a flywheel, with the kinetic energy of the vehicle during regenerative braking

Force-velocity properties' contribution to bilateral deficit during ballistic push-off.

Science.gov (United States)

Samozino, Pierre; Rejc, Enrico; di Prampero, Pietro Enrico; Belli, Alain; Morin, Jean-Benoît

2014-01-01

The objective of this study is to quantify the contribution of the force-velocity (F-v) properties to bilateral force deficit (BLD) in ballistic lower limb push-off and to relate it to individual F-v mechanical properties of the lower limbs. The F-v relation was individually assessed from mechanical measurements for 14 subjects during maximal ballistic lower limb push-offs; its contribution to BLD was then investigated using a theoretical macroscopic approach, considering both the mechanical constraints of movement dynamics and the maximal external capabilities of the lower limb neuromuscular system. During ballistic lower limb push-off, the maximum force each lower limb can produce was lower during bilateral than unilateral actions, thus leading to a BLD of 36.7% ± 5.7%. The decrease in force due to the F-v mechanical properties amounted to 19.9% ± 3.6% of the force developed during BL push-offs, which represents a nonneural contribution to BLD of 43.5% ± 9.1%. This contribution to BLD that cannot be attributed to changes in neural features was negatively correlated to the maximum unloaded extension velocity of the lower limb (r = -0.977, P push-off, BLD is due to both neural alterations and F-v mechanical properties, the latter being associated with the change in movement velocity between bilateral and unilateral actions. The level of the contribution of the F-v properties depends on the individual F-v mechanical profile of the entire lower limb neuromuscular system: the more the F-v profile is oriented toward velocity capabilities, the lower the loss of force from unilateral to bilateral push-offs due to changes in movement velocity.

Muscular contribution to low-back loading and stiffness during standard and suspended push-ups.

Science.gov (United States)

Beach, Tyson A C; Howarth, Samuel J; Callaghan, Jack P

2008-06-01

Push-up exercises are normally performed to challenge muscles that span upper extremity joints. However, it is also recognized that push-ups provide an effective abdominal muscle challenge, especially when the hands are in contact with a labile support surface. The purpose of this study was to compare trunk muscle activation levels and resultant intervertebral joint (IVJ) loading when standard and suspended push-ups were performed, and to quantify and compare the contribution of trunk muscles to IVJ rotational stiffness in both exercises. Eleven recreationally trained male volunteers performed sets of standard and suspended push-ups. Upper body kinematic, kinetic, and EMG data were collected and input into a 3D biomechanical model of the lumbar torso to quantify lumbar IVJ loading and the contributions of trunk muscles to IVJ rotational stiffness. When performing suspended push-ups, muscles of the abdominal wall and the latissimus dorsi were activated to levels that were significantly greater than those elicited when performing standard push-ups (ppush-ups. Also directly resulting from the increased activation levels of the abdominal muscles and the latissimus dorsi during suspended push-ups was increased muscular contribution to lumbar IVJ rotational stiffness (ppush-ups appear to provide a superior abdominal muscle challenge. However, for individuals unable to tolerate high lumbar IVJ compressive loads, potential benefits gained by incorporating suspended push-ups into their resistance training regimen may be outweighed by the risk of overloading low-back tissues.

Push-Pull Ventilation in a Painting Shop for Large Steel Constructions

DEFF Research Database (Denmark)

Svidt, Kjeld; Heiselberg, Per

This paper describes the analysis of a push-pull ventilation system for a painting shop that is used for painting steel chimneys and windmill towers.......This paper describes the analysis of a push-pull ventilation system for a painting shop that is used for painting steel chimneys and windmill towers....

Methods of pushing during vaginal delivery and pelvic floor and perineal outcomes: a review.

Science.gov (United States)

de Tayrac, Renaud; Letouzey, Vincent

2016-12-01

Over the past 20 years, several randomized studies have compared Valsalva and spontaneous pushing techniques during vaginal delivery. This review summarizes current medical knowledge concerning their maternal and fetal consequences, focusing on pelvic and perineal outcomes. We selected nine randomized controlled trials comparing Valsalva and spontaneous pushing, and a secondary analysis of a randomized controlled trial comparing different methods of perineal protection. Two trials showed that spontaneous pushing reduces the risk of perineal tears, but no firm conclusions can be drawn given the heterogeneity and inconsistent results of these studies. Conflicting results have been reported regarding the duration of the second stage of labor. Pushing technique does not seem to affect episiotomy, instrumental delivery or cesarean rates. Maternal satisfaction seems to be better after spontaneous pushing. Spontaneous pushing appears to have no adverse effects on neonatal well being, and one study showed a significant improvement in prenatal fetal parameters during the expulsive phase. Valsalva and spontaneous pushing techniques currently appear comparable in terms of duration, pelvic floor, perineal, and neonatal outcomes. In the absence of strong evidence in favor of either technique, the decision should be guided by patient preference and the clinical situation. Additional, well-designed randomized controlled trials are required.

Trials and Tribulations: Student Approaches and Difficulties with Proposing Mechanisms Using the Electron-Pushing Formalism

Science.gov (United States)

Bhattacharyya, Gautam

2014-01-01

The skill of proposing mechanisms of reactions using the electron-pushing formalism (EPF) is not only of value to practicing organic chemists but it is also emphasized to students enrolled in organic chemistry courses at all levels. Several research studies in the past decade have documented the difficulties that undergraduate, and even graduate…

How does the duration of active pushing in labor affect neonatal outcomes?

Science.gov (United States)

Yli, Branka M; Kro, Grete A Birkeland; Rasmussen, Svein; Khoury, Janette; Norèn, Håkan; Amer-Wåhlin, Isis; Saugstad, Ola Didrik; Stray-Pedersen, Babill

2011-11-19

To assess the effect of time of active pushing (TAP) on neonatal outcome. The study population (n=36,432) was taken from a Swedish randomized control trial on intrapartum monitoring, a European Union fetal electrocardiogram trial, and from Mölndal Hospital. After validation of acid-base samples and TAP, 22,812 cases were accepted for analysis. The median active TAP was 36 min for P0 and 13 min for P≥1 (Ppushing for 15-29 min (n=6589) relative to pushing for 12 mmol/L to 3.5 (95% CI 1.3-9.0). The group with a cord artery pH of 15 min), while the probability of a spontaneous vaginal delivery decreased with the duration of pushing. We suggest active physiological evaluation of the labor progress together with continuous electronic fetal monitoring during pushing irrespective of guideline thresholds.

Push technology at Argonne National Laboratory.

Energy Technology Data Exchange (ETDEWEB)

Noel, R. E.; Woell, Y. N.

1999-04-06

Selective dissemination of information (SDI) services, also referred to as current awareness searches, are usually provided by periodically running computer programs (personal profiles) against a cumulative database or databases. This concept of pushing relevant content to users has long been integral to librarianship. Librarians traditionally turned to information companies to implement these searches for their users in business, academia, and the science community. This paper describes how a push technology was implemented on a large scale for scientists and engineers at Argonne National Laboratory, explains some of the challenges to designers/maintainers, and identifies the positive effects that SDI seems to be having on users. Argonne purchases the Institute for Scientific Information (ISI) Current Contents data (all subject areas except Humanities), and scientists no longer need to turn to outside companies for reliable SDI service. Argonne's database and its customized services are known as ACCESS (Argonne-University of Chicago Current Contents Electronic Search Service).

A demonstration of NIOSH push-pull ventilation criteria.

Science.gov (United States)

Klein, M K

1987-03-01

This paper summarizes the results of a study performed on an actual chrome plating tank in order to validate criteria for push-pull ventilation systems developed by Huebener and Hughes at NIOSH. Validation of the criteria was made by taking area industrial hygiene samples for hexavalent and total chrome at ten locations around the plating tank. The sampling was performed during actual production runs or while the tank was operating with a dummy load. The sampling data are summarized. The data show that the push-pull system, operating at Huebener's criteria, could control emissions to below the current standards and guidelines. Conclusions and recommendations are included.

Initial Assessment of the Acceptability of a Push-Pull Aedes aegypti Control Strategy in Iquitos, Peru and Kanchanaburi, Thailand

Science.gov (United States)

Paz-Soldan, Valerie A.; Plasai, Valaikanya; Morrison, Amy C.; Rios-Lopez, Esther J.; Guedez-Gonzales, Shirly; Grieco, John P.; Mundal, Kirk; Chareonviriyaphap, Theeraphap; Achee, Nicole L.

2011-01-01

As part of a larger research program evaluating chemical threshold levels for a Push-Pull intervention to reduce man-vector (Aedes aegypti) contact, this qualitative study explored local perceptions and strategies associated with mosquito control within dengue-endemic communities in Peru and Thailand. Focus groups were used to provide preliminary information that would identify possible public acceptance issues to the Push-Pull strategy in each site. Nine focus group discussions (total of 102 individuals) conducted between September 2008 and March 2009 examined several themes: 1) current mosquito control practices; 2) perceptions of spatial repellency and contact irritancy versus killing mosquitoes; and 3) initial perceptions toward mosquito host-seeking traps. Results indicate participants use household-level strategies for insect control that reveal familiarity with the concept of spatial repellent and contact irritant actions of chemicals and that placing traps in the peridomestic environment to remove repelled mosquitoes was acceptable. Preliminary evidence suggests a Push-Pull strategy should be well accepted in these locations. These results will be beneficial for developing future large scale push-pull interventions and are currently being used to guide insecticide application strategies in (entomological) proof-of-concept studies using experimental huts. PMID:21292886

What Explains the Survival Gap of Pushed and Pulled Corporate Spin-offs?

DEFF Research Database (Denmark)

Rocha, Vera; Carneiro, Anabela; Varum, Celeste

2015-01-01

Unconditionally, pushed spin-offs are found to survive longer than their pulled counterparts. Using matched employer-employee data and novel multivariate decomposition techniques, we show that pushed spin-offs’ relative survival advantage is mostly explained by their larger human capital endowments...

The push factors of intra-urban residential mobility in Calabar, Nigeria

African Journals Online (AJOL)

The paper takes a critical look at the push factors of intra-urban residential mobility in Calabar. Push factors are defined as those which operate to induce or encourage households to change their residence in the city. The paper notes that changing of residence by urban households in Western cities is a common ...

Beyond Knut Holt's fusion model, balancing market pull and technology push

NARCIS (Netherlands)

Nagel, A.P.

2003-01-01

Should a firm rely on market pull or on technology push? Some scholars have extreme opinions on this and firms do switch emphasis on push and pull over time. Knut Holt, the first president of ISPIM, presented his so-called Fusion Model in the early 1970s to shed light onto this debate. This paper

Human Body Mechanics of Pushing and Pulling: Analyzing the Factors of Task-related Strain on the Musculoskeletal System.

Science.gov (United States)

Argubi-Wollesen, Andreas; Wollesen, Bettina; Leitner, Martin; Mattes, Klaus

2017-03-01

The purpose of this review is to name and describe the important factors of musculoskeletal strain originating from pushing and pulling tasks such as cart handling that are commonly found in industrial contexts. A literature database search was performed using the research platform Web of Science. For a study to be included in this review differences in measured or calculated strain had to be investigated with regard to: (1) cart weight/ load; (2) handle position and design; (3) exerted forces; (4) handling task (push and pull); or (5) task experience. Thirteen studies met the inclusion criteria and proved to be of adequate methodological quality by the standards of the Alberta Heritage Foundation for Medical Research. External load or cart weight proved to be the most influential factor of strain. The ideal handle positions ranged from hip to shoulder height and were dependent on the strain factor that was focused on as well as the handling task. Furthermore, task experience and subsequently handling technique were also key to reducing strain. Workplace settings that regularly involve pushing and pulling should be checked for potential improvements with regards to lower weight of the loaded handling device, handle design, and good practice guidelines to further reduce musculoskeletal disease prevalence.

Do maternal pushing techniques during labour affect obstetric or neonatal outcomes?

Science.gov (United States)

Barasinski, C; Lemery, D; Vendittelli, F

2016-10-01

To assess, through a literature review, the maternal and neonatal morbidity associated with the type of pushing used during the second stage of labour. We searched the Cochrane Library and the Medline database for randomised controlled trials from 1980 to 2015, using the following keywords: "delivery", "birth", "birthing", "bearing down, coached, uncoached, pushing", "second and stage and labour", "randomised controlled trials" and "meta-analysis". Seven randomised controlled trials were found. Interventions varied between the studies. In the intervention groups, open-glottis pushing was spontaneous or coached. The groups did not differ for perineal injuries, episiotomies or type of birth. Impact on pelvic floor structure varied between the studies. Only one study found a better 5-minute Apgar score and a better umbilical artery pH in the "open glottis" group. The low methodological quality of the studies and the differences between the protocols do not justify a recommendation of a particular pushing technique. Further studies appear necessary to study outcomes with each of these techniques. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Accuracy of clinical observations of push-off during gait after stroke.

Science.gov (United States)

McGinley, Jennifer L; Morris, Meg E; Greenwood, Ken M; Goldie, Patricia A; Olney, Sandra J

2006-06-01

To determine the accuracy (criterion-related validity) of real-time clinical observations of push-off in gait after stroke. Criterion-related validity study of gait observations. Rehabilitation hospital in Australia. Eleven participants with stroke and 8 treating physical therapists. Not applicable. Pearson product-moment correlation between physical therapists' observations of push-off during gait and criterion measures of peak ankle power generation from a 3-dimensional motion analysis system. A high correlation was obtained between the observational ratings and the measurements of peak ankle power generation (Pearson r =.98). The standard error of estimation of ankle power generation was .32W/kg. Physical therapists can make accurate real-time clinical observations of push-off during gait following stroke.

Low-back and shoulder complaints among workers with pushing and pulling tasks

NARCIS (Netherlands)

Hoozemans, Marco J. M.; van der Beek, Allard J.; Fring-Dresen, Monique H. W.; van der Woude, Luc H. V.; van Dijk, Frank J. H.

2002-01-01

Objectives Low-back and shoulder complaints were examined in relation to self-reported and objectively assessed exposure to work-related pushing and pulling. Methods Workers from several companies (eg, nursing homes and flower auctions) with pushing and pulling tasks and, as reference, workers

Biomechanical study of the final push-pull in archery.

Science.gov (United States)

Leroyer, P; Van Hoecke, J; Helal, J N

1993-02-01

The purpose of this study was to analyse archery performance among eight archers of different abilities by means of displacement pull-hand measurements during the final push-pull phase of the shoot. The archers showed an irregular displacement negatively related to their technical level. Displacement signal analysis showed high power levels in both the 0-5 Hz and 8-12 Hz ranges. The latter peak corresponds to electromyographic tremor observed during a prolonged push-pull effort. The results are discussed in relation to some potentially helpful training procedures such as biofeedback and strength conditioning.

Pushing concentration of stationary solar concentrators to the limit.

Science.gov (United States)

Winston, Roland; Zhang, Weiya

2010-04-26

We give the theoretical limit of concentration allowed by nonimaging optics for stationary solar concentrators after reviewing sun- earth geometry in direction cosine space. We then discuss the design principles that we follow to approach the maximum concentration along with examples including a hollow CPC trough, a dielectric CPC trough, and a 3D dielectric stationary solar concentrator which concentrates sun light four times (4x), eight hours per day year around.

Bench press and push-up at comparable levels of muscle activity results in similar strength gains.

Science.gov (United States)

Calatayud, Joaquin; Borreani, Sebastien; Colado, Juan C; Martin, Fernando; Tella, Victor; Andersen, Lars L

2015-01-01

Electromyography (EMG) exercise evaluation is commonly used to measure the intensity of muscle contraction. Although researchers assume that biomechanically comparable resistance exercises with similar high EMG levels will produce similar strength gains over the long term, no studies have actually corroborated this hypothesis. This study evaluated EMG levels during 6 repetition maximum (6RM) bench press and push-up, and subsequently performed a 5-week training period where subjects were randomly divided into 3 groups (i.e., 6RM bench press group, 6RM elastic band push-up group, or control group) to evaluate muscle strength gains. Thirty university students with advanced resistance training experience participated in the 2-part study. During the training period, exercises were performed using the same loads and variables that were used during the EMG data collection. At baseline, EMG amplitude showed no significant difference between 6RM bench press and band push-up. Significant differences among the groups were found for percent change (Δ) between pretest and posttest for 6RM (p = 0.017) and for 1 repetition maximum (1RM) (p bench press group and 6RM elastic band push-up group improved their 1RM and 6RM (Δ ranging from 13.65 to 22.21) tests significantly with similar gains, whereas control group remains unchanged. Thus, when the EMG values are comparable and the same conditions are reproduced, the aforementioned exercises can provide similar muscle strength gains.

Structural Change Out of Agriculture: Labor Push versus Labor Pull

OpenAIRE

Francisco Alvarez-Cuadrado; Markus Poschke

2011-01-01

The process of economic development is characterized by substantial rural-urban migrations and a decreasing share of agriculture in output and employment. The literature highlights two main engines behind this process of structural change: (i) improvements in agricultural technology combined with the effect of Engel's law of demand push resources out of the agricultural sector (the "labor push" hypothesis), and (ii) improvements in industrial technology attract labor into this sector (the "la...

Stability and Scalability of the CMS Global Pool: Pushing HTCondor and GlideinWMS to New Limits

Energy Technology Data Exchange (ETDEWEB)

Balcas, J. [Caltech; Bockelman, B. [Nebraska U.; Hufnagel, D. [Fermilab; Hurtado Anampa, K. [Notre Dame U.; Aftab Khan, F. [NCP, Islamabad; Larson, K. [Fermilab; Letts, J. [UC, San Diego; Marra da Silva, J. [Sao Paulo, IFT; Mascheroni, M. [Fermilab; Mason, D. [Fermilab; Perez-Calero Yzquierdo, A. [Madrid, CIEMAT; Tiradani, A. [Fermilab

2017-11-22

The CMS Global Pool, based on HTCondor and glideinWMS, is the main computing resource provisioning system for all CMS workflows, including analysis, Monte Carlo production, and detector data reprocessing activities. The total resources at Tier-1 and Tier-2 grid sites pledged to CMS exceed 100,000 CPU cores, while another 50,000 to 100,000 CPU cores are available opportunistically, pushing the needs of the Global Pool to higher scales each year. These resources are becoming more diverse in their accessibility and configuration over time. Furthermore, the challenge of stably running at higher and higher scales while introducing new modes of operation such as multi-core pilots, as well as the chaotic nature of physics analysis workflows, places huge strains on the submission infrastructure. This paper details some of the most important challenges to scalability and stability that the CMS Global Pool has faced since the beginning of the LHC Run II and how they were overcome.

Push Recovery for Humanoid Robot in Dynamic Environment and Classifying the Data Using K-Mean

Directory of Open Access Journals (Sweden)

Anubha Parashar

2016-12-01

Full Text Available Push recovery is prime ability that is essential to be incorporated in the process of developing a robust humanoid robot to support bipedalism. In real environment it is very essential for humanoid robot to maintain balance. In this paper we are generating a control system and push recovery controller for humanoid robot walking. We apply different kind of pushes to humanoid robot and the algorithm that can bring a change in the walking stage to sustain walking. The simulation is done in 3D environment using Webots. This paper describes techniques for feature selection to foreshow push recovery for hip, ankle and knee joint. We train the system by K-Mean algorithm and testing is done on crouch data and tested results are reported. Random push data of humanoid robot is collected and classified to see whether push lie in safer region and then tested on given proposed system.

Interfacial push-out measurements of fully-bonded SiC/SiC composites

International Nuclear Information System (INIS)

Snead, L.L.; Steiner, D.; Zinkle, S.J.

1990-01-01

The direct measurement of interfacial bond strength and frictional resistance to sliding in a fully-bonded SiC/SiC composite is measured. It is shown that a fiber push-out technique can be utilized for small diameter fibers and very thin composite sections. Results are presented for a 22 micron thick section for which 37 out of 44 Nicalon fibers tested were pushed-out within the maximum nanoindentor load of 120 mN. Fiber interfacial yielding, push-out and sliding resistance were measured for each fiber. The distribution of interfacial strengths is treated as being Weibull in form. 14 refs., 5 figs

The impact of pushed output on accuracy and fluency of Iranian EFL learners’ speaking

Directory of Open Access Journals (Sweden)

Aram Reza Sadeghi Beniss

2014-07-01

Full Text Available The current study attempted to establish baseline quantitative data on the impacts of pushed output on two components of speaking (i.e., accuracy and fluency. To achieve this purpose, 30 female EFL learners were selected from a whole population pool of 50 based on the standard test of IELTS interview and were randomly assigned into an experimental group and a control group. The participants in the experimental group received pushed output treatment while the students in the control group received non-pushed output instruction. The data were collected through IELTS interview and then the interview of each participant was separately tape-recorded and later transcribed and coded to measure accuracy and fluency. Then, the independent samples t-test was employed to analyze the collected data. The results revealed that the experimental group outperformed the control group in accuracy. In contrast, findings substantiated that pushed output had no impact on fluency. The positive impact of pushed output demonstrated in this study is consistent with the hypothesized function of Swain’s (1985 pushed output. The results can provide some useful insights into syllabus design and English language teaching.

Why People Choose to Teach in Urban Schools: The Case for a Push-Pull Factor Analysis

Science.gov (United States)

Knell, Paul F.; Castro, Antonio J.

2014-01-01

This qualitative research study traces the motivations for teaching of 13 teacher candidates enrolled in an urban-based alternative certification program. After using a push-pull factor analysis, the data suggest that most participants left their previous careers due to financial shortcomings or work instability. As a result, these participants…

Pushing hard on the accelerator

Energy Technology Data Exchange (ETDEWEB)

Anon.

1987-09-15

The quest for new techniques to drive future generations of particle accelerators has been pushed hard in recent years, efforts having been highlighted by workshops in Europe, organized by the European Committee for Future Accelerators, and in the US. The latest ECFA Workshop on New Developments in Particle Acceleration Techniques, held at Orsay from 29 June to 4 July, showed how the initial frantic search for innovation is now maturing.

The effect of klapskate hinge position on push-off performance: a simulation study

OpenAIRE

Houdijk, J.H.P.; Bobbert, M.F.; de Koning, J.J.; de Groot, G.

2003-01-01

Purpose: The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. Method: For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this m...

Itinerant deaf educator and general educator perceptions of the D/HH push-in model.

Science.gov (United States)

Rabinsky, Rebecca J

2013-01-01

A qualitative case study using the deaf and hard of hearing (D/HH) push-in model was conducted on the perceptions of 3 itinerant deaf educators and 3 general educators working in 1 school district. Participants worked in pairs of 1 deaf educator and 1 general educator at 3 elementary schools. Open-ended research questions guided the study, which was concerned with teachers' perceptions of the model in general and with the model's advantages, disadvantages, and effectiveness. Data collected from observations, one-to-one interviews, and a focus group interview enabled the investigator to uncover 4 themes: Participants (a) had an overall positive experience, (b) viewed general education immersion as an advantage, (c) considered high noise levels a disadvantage, and (d) believed the effectiveness of the push-in model was dependent on several factors, in particular, the needs of the student and the nature of the general education classroom environment.

Accuracy and reliability of observational gait analysis data: judgments of push-off in gait after stroke.

Science.gov (United States)

McGinley, Jennifer L; Goldie, Patricia A; Greenwood, Kenneth M; Olney, Sandra J

2003-02-01

Physical therapists routinely observe gait in clinical practice. The purpose of this study was to determine the accuracy and reliability of observational assessments of push-off in gait after stroke. Eighteen physical therapists and 11 subjects with hemiplegia following a stroke participated in the study. Measurements of ankle power generation were obtained from subjects following stroke using a gait analysis system. Concurrent videotaped gait performances were observed by the physical therapists on 2 occasions. Ankle power generation at push-off was scored as either normal or abnormal using two 11-point rating scales. These observational ratings were correlated with the measurements of peak ankle power generation. A high correlation was obtained between the observational ratings and the measurements of ankle power generation (mean Pearson r=.84). Interobserver reliability was moderately high (mean intraclass correlation coefficient [ICC (2,1)]=.76). Intraobserver reliability also was high, with a mean ICC (2,1) of.89 obtained. Physical therapists were able to make accurate and reliable judgments of push-off in videotaped gait of subjects following stroke using observational assessment. Further research is indicated to explore the accuracy and reliability of data obtained with observational gait analysis as it occurs in clinical practice.

Pushing the limits of spatial resolution with the Kuiper Airborne observatory

Science.gov (United States)

Lester, Daniel

1994-01-01

The study of astronomical objects at high spatial resolution in the far-IR is one of the most serious limitations to our work at these wavelengths, which carry information about the luminosity of dusty and obscured sources. At IR wavelengths shorter than 30 microns, ground based telescopes with large apertures at superb sites achieve diffraction-limited performance close to the seeing limit in the optical. At millimeter wavelengths, ground based interferometers achieve resolution that is close to this. The inaccessibility of the far-IR from the ground makes it difficult, however, to achieve complementary resolution in the far-IR. The 1983 IRAS survey, while extraordinarily sensitive, provides us with a sky map at a spatial resolution that is limited by detector size on a spatial scale that is far larger than that available in other wavelengths on the ground. The survey resolution is of order 4 min in the 100 micron bandpass, and 2 min at 60 microns (IRAS Explanatory Supplement, 1988). Information on a scale of 1' is available on some sources from the CPC. Deconvolution and image resolution using this database is one of the subjects of this workshop.

Failure conditions from push out tests of a steel-concrete joint: fracture mechanics approach

Czech Academy of Sciences Publication Activity Database

Klusák, Jan; Seitl, Stanislav; De Corte, W.; Helincks, P.; Boel, V.; De Schutter, G.

488-489, - (2012), s. 710-713 ISSN 1013-9826. [International Conference on Fracture and Damage Mechanics - FDM 2011 /10./. Dubrovník, 19.09.2011-21.09.2011] R&D Projects: GA ČR GAP108/10/2049 Institutional research plan: CEZ:AV0Z20410507 Keywords : Push out test * generalized linear elastic fracture mechanics * bi-material notch Subject RIV: JL - Materials Fatigue, Friction Mechanics

Development of remote fuel pushing system in Reprocessing Plant, Tarapur

International Nuclear Information System (INIS)

Chandra, Munish; Coelho, G.; Kodilkar, S.S.; Mishra, A.K.; Bajpai, D.D.; Nair, M.K.T.

1990-01-01

Power Reactor Fuel Reprocessing Plant (PREFRE), Tarapur has been processing spent fuel arising from Pressurized Heavy Water Reactors for quite some time. The process adopted in the plant is purex process with chopleach head end treatment. The head end treatment involves loading of ten spent fuel bundles in the charging cask at a time in the fuel bay and aligning the cask with the transfer port and subsequently pushing all the ten bundles together into the fuel magazine. At present the fuel is pushed into the magazine manually. Since the ten bundles weigh approximately 200 Kg. and involves pushing of 9.4 meters length, the operation is carried out using stainless steel screwed pipes, in steps of five lengths. The entire operation requires a large number of trained skilled workers and is found to be tedious. To solve this problem a hydraulic cum pneumatic fuel pushing system has been designed, fabricated, tested and is in the process of installation in the fuel handling area. This paper describes various requirements, constraints and dimensional details arising in the incorporation of such a system to be back fitted in an existing plant, though many of these constraints can be avoided in future plants. Further, complete sequence of operations, technical specifications regarding the telescopic hydraulic power pack and associated controls incorporated in the system are highlighted. (author). 2 figs

Surface microstructures on planar substrates and textile fibers guide neurite outgrowth: a scaffold solution to push limits of critical nerve defect regeneration?

Directory of Open Access Journals (Sweden)

Stefan Weigel

Full Text Available The treatment of critical size peripheral nerve defects represents one of the most serious problems in neurosurgery. If the gap size exceeds a certain limit, healing can't be achieved. Connection mismatching may further reduce the clinical success. The present study investigates how far specific surface structures support neurite outgrowth and by that may represent one possibility to push distance limits that can be bridged. For this purpose, growth cone displacement of fluorescent embryonic chicken spinal cord neurons was monitored using time-lapse video. In a first series of experiments, parallel patterns of polyimide ridges of different geometry were created on planar silicon oxide surfaces. These channel-like structures were evaluated with and without amorphous hydrogenated carbon (a-C:H coating. In a next step, structured and unstructured textile fibers were investigated. All planar surface materials (polyimide, silicon oxide and a-C:H proved to be biocompatible, i.e. had no adverse effect on nerve cultures and supported neurite outgrowth. Mean growth cone migration velocity measured on 5 minute base was marginally affected by surface structuring. However, surface structure variability, i.e. ridge height, width and inter-ridge spacing, significantly enhanced the resulting net velocity by guiding the growth cone movement. Ridge height and inter-ridge distance affected the frequency of neurites crossing over ridges. Of the evaluated dimensions ridge height, width, and inter-ridge distance of respectively 3, 10, and 10 µm maximally supported net axon growth. Comparable artificial grooves, fabricated onto the surface of PET fibers by using an excimer laser, showed similar positive effects. Our data may help to further optimize surface characteristics of artificial nerve conduits and bioelectronic interfaces.

Tunicates push the limits of animal evo-devo

Directory of Open Access Journals (Sweden)

Ferrier David EK

2011-01-01

Full Text Available Abstract The phylum to which humans belong, Chordata, takes its name from one of the major shared derived features of the group, the notochord. All chordates have a notochord, at least during embryogenesis, and there is little doubt about notochord homology at the morphological level. A study in BMC Evolutionary Biology now shows that there is greater variability in the molecular genetics underlying notochord development than previously appreciated. See research article: http://www.biomedcentral.com/1471-2148/11/21

Upper body push and pull strength ratio in recreationally active adults.

Science.gov (United States)

Negrete, Rodney J; Hanney, William J; Pabian, Patrick; Kolber, Morey J

2013-04-01

Agonist to antagonist strength data is commonly analyzed due to its association with injury and performance. The purpose of this study was to examine the agonist to antagonist ratio of upper body strength using two simple field tests (timed push up/timed modified pull up) in recreationally active adults and to establish the basis for reference standards. One hundred eighty (180) healthy recreationally active adults (111 females and 69 males, aged 18-45 years) performed two tests of upper body strength in random order: 1. Push-ups completed during 3 sets of 15 seconds with a 45 second rest period between each set and 2. Modified pull-ups completed during 3 sets of 15 seconds with a 45 second rest period between each set. The push-up to modified pull-up ratio for the males was 1.57:1, whereas females demonstrated a ratio of 2.72:1. The results suggest that for our group of healthy recreationally active subjects, the upper body "pushing" musculature is approximately 1.5-2.7 times stronger than the musculature involved for pulling. In this study, these recreationally active adults displayed greater strength during the timed push-ups than the modified pull-ups. The relationship of these imbalances to one's performance and or injury risk requires further investigation. The reference values, however, may serve the basis for future comparison and prospective investigations. The field tests in this study can be easily implemented by clinicians and an agonist/antagonist ratio can be determined and compared to our findings. 2b.

Push-off mechanics in speed skating with conventional skates and klapskates.

Science.gov (United States)

Houdijk, H; de Koning, J J; de Groot, G; Bobbert, M F; And; van Ingen Schenau, G J

2000-03-01

Personal and world records in speed skating improved tremendously after the introduction of the klapskate, which allows the foot to plantar flex at the end of the push-off while the full blade continues to glide on the ice. The purpose of this study was to gain insight into the differences in skating technique with conventional versus klapskates and to unveil the source of power enhancement using klapskates. Ten elite speed skaters skated four 400-m laps at maximal effort with both conventional and klapskates. On the straight high-speed film, push-off force and EMG data were collected. An inverse dynamics analysis was performed in the moving reference plane through hip, knee, and ankle. Skating velocity increased 5% as a result of an increase in mean power output of 25 W when klapskates were used instead of conventional skates. The increase in mean power output was achieved through an 11-J increase in work per stroke and an increase in stroke frequency from 1.30 to 1.36 strokes x s(-1). The difference in work per stroke occurs during the final 50 ms of the push-off. This is the result of the ineffective way in which push-off forces are generated with conventional skates when the foot rotates about the long front end of the blade. No differences in muscle coordination were observed from EMG. A hinge under the ball of the foot enhances the effectiveness of plantar flexion during the final 50 ms of the push off with klapskates and increases work per stroke and mean power output.

A unified perspective on ankle push-off in human walking

OpenAIRE

Zelik, Karl E.; Adamczyk, Peter G.

2016-01-01

Muscle–tendon units about the ankle joint generate a burst of positive power during the step-to-step transition in human walking, termed ankle push-off, but there is no scientific consensus on its functional role. A central question embodied in the biomechanics literature is: does ankle push-off primarily contribute to leg swing, or to center of mass (COM) acceleration? This question has been debated in various forms for decades. However, it actually presents a false dichotomy, as these two p...

The push-pull tactic for mitigation of mountain pine beetle (Coleoptera: Curculionidae) damage in lodgepole and whitebark pines.

Science.gov (United States)

Gillette, Nancy E; Mehmel, Constance J; Mori, Sylvia R; Webster, Jeffrey N; Wood, David L; Erbilgin, Nadir; Owen, Donald R

2012-12-01

In an attempt to improve semiochemical-based treatments for protecting forest stands from bark beetle attack, we compared push-pull versus push-only tactics for protecting lodgepole pine (Pinus contorta Douglas ex Loudon) and whitebark pine (Pinus albicaulis Engelm.) stands from attack by mountain pine beetle (Dendroctonus ponderosae Hopkins) in two studies. The first was conducted on replicated 4.04-ha plots in lodgepole pine stands (California, 2008) and the second on 0.81-ha plots in whitebark pine stands (Washington, 2010). In both studies, D. ponderosae population levels were moderate to severe. The treatments were 1) push-only (D. ponderosae antiaggregant semiochemicals alone); 2) push-pull (D. ponderosae antiaggregants plus perimeter traps placed at regular intervals, baited with four-component D. ponderosae aggregation pheromone); and 3) untreated controls. We installed monitoring traps baited with two-component D. ponderosae lures inside each plot to assess effect of treatments on beetle flight. In California, fewer beetles were collected in push-pull treated plots than in control plots, but push-only did not have a significant effect on trap catch. Both treatments significantly reduced the rate of mass and strip attacks by D. ponderosae, but the difference in attack rates between push-pull and push-only was not significant. In Washington, both push-pull and push-only treatments significantly reduced numbers of beetles caught in traps. Differences between attack rates in treated and control plots in Washington were not significant, but the push-only treatment reduced attack rates by 30% compared with both the control and push-pull treatment. We conclude that, at these spatial scales and beetle densities, push-only may be preferable for mitigating D. ponderosae attack because it is much less expensive, simpler, and adding trap-out does not appear to improve efficacy.

Impact of hand forces and start/stop frequency on physiological responses to three forms of pushing and pulling: a South African perspective.

Science.gov (United States)

Ai, Todd

2012-01-01

There has been limited attention given to the physiological demands of pushing and pulling, especially in industrially developing countries such as South Africa. Two key factors affecting the physiological demands of these tasks are the hand forces exerted and the start/stop frequency. The purpose of the current study was therefore to investigate the physiological responses to pushing and pulling at various loads and start/stop frequencies. 36 male subjects participated in the study and were required to complete a total of 18 conditions (three techniques: pushing, two- and one-handed pulling; three loads: 200, 350 and 500 kg; and two frequencies: 2 and 4 stops per minute). During each condition the heart rate, oxygen uptake and energy expenditure were measured. Pushing was found to elicit significantly lower responses for all three dependent variables than either form of pulling. The start/stop frequency was also found to have a significant impact on subject responses. The findings of this study indicate that the technique adopted to maneuver loads is critical in determining the physical demands placed on the human operator. Furthermore increasing the frequency of start/stops plays an important role, thus the forces exerted during these two phases are important from a physiological perspective.

Shoulder muscle activation during stable and suspended push-ups at different heights in healthy subjects.

Science.gov (United States)

Borreani, Sebastien; Calatayud, Joaquin; Colado, Juan C; Tella, Victor; Moya-Nájera, Diego; Martin, Fernando; Rogers, Michael E

2015-08-01

To analyze shoulder muscle activation when performing push-ups under different stability conditions and heights. Comparative study by repeated measures. Valencia University laboratory. 29 healthy males participated. Subjects performed 3 push-ups each with their hands at 2 different heights (10 vs. 65 cm) under stable conditions and using a suspension device. Push-up speed was controlled and the testing order was randomized. The average amplitudes of the electromyographic root mean square of the long head of the triceps brachii (TRICEP), upper trapezius (TRAPS), anterior deltoid (DELT) and clavicular pectoralis (PEC) were recorded. The electromyographic signals were normalized to the maximum voluntary isometric contraction (MVIC). Suspended push-ups at 10 cm resulted in greater activation in the TRICEP (17.14 ± 1.31 %MVIC vs. 37.03 ± 1.80 %MVIC) and TRAPS (5.83 ± 0.58 %MVIC vs. 14.69 ± 1.91 %MVIC) than those performed on the floor. For DELT and PEC similar or higher activation was found performing the push-ups on the floor, respectively. Height determines different muscle activation patterns. Stable push-ups elicit similar PEC and higher DELT muscle activation, being greater at 10 cm; whereas suspended push-ups elicit greater TRAPS and TRICEP muscle activation, being greater at 65 cm. Copyright © 2014 Elsevier Ltd. All rights reserved.

Push Characteristics in Wheelchair Court Sport Sprinting

NARCIS (Netherlands)

van der Slikke, Rienk M A; Berger, Monique; Bregman, Daan; Veeger, Dirkjan

2016-01-01

Short sprints are important components of most wheelchair court sports, since being faster than the opponent often determines keeping ball possession or not. Sprinting capacity is best measured during a field test, allowing the athlete to freely choose push strategies adapted to their own wheelchair

Push characteristics in wheelchair court sport sprinting

NARCIS (Netherlands)

van der Slikke, R.M.A.; Berger, Monique; Bregman, D.J.J.; Veeger, H.E.J.; van der Helm, FCT; Jansen, AJ

2016-01-01

Short sprints are important components of most wheelchair court sports, since being faster than the opponent often determines keeping ball possession or not. Sprinting capacity is best measured during a field test, allowing the athlete to freely choose push strategies adapted to their own

Modelling the behaviour of the push-pull gel dosimeter

International Nuclear Information System (INIS)

Bosi, S.G.; Davies, J.B.; Gorjiara, T.; Baldock, C.

2010-01-01

Full text: Recent development of a gel dosimeter based on the radiobleaching pigment, genipin, allows development of a new 3D optically scanned gel dosimeter-the p ush-pull g el. This gel would contain two spectrally complementary pigments, one which darkens with dose and another (e.g. genipin) which bleaches. The two pigments deal separately with the high and low dose ends of the dosimeter's dynamic range. The bleaching pigment would be optimised for high sensitivity and the darkening pigment for low. Employing dual pigments, optimised independently, relaxes the need for compromise between sensitivity at low dose and accuracy at high dose. Such a gel, after exposure, would be read using two successive optical CT scans, at two different wavelengths. The reduction in sensitivity of the darkening pigment (allowed by the use of push-pull) would reduce the occurrence of regions of high optical attenuation which can generate optical CT artefacts. Simulated optical CT reconstructions of the optical density map (Fig. La) scanned at the darkening pigment wavelength of a hypothetical push-pull gel, confirms the reduction in susceptibility to artefacts. Fig. I b shows a profile through the map with no stray light added. The centre of the profile in Fig. I d shows a cupping artefact produced by 10 ppm of stray light. The similarity of Fig. Ic and b show that a 30% sensitivity reduction allowed by push-pull, renders the artefact negligible. This paper presents the results of' these simulations of a push-pull gel scanned using optical CT and also some results of experiments with genipin gel. (author)

Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.

Science.gov (United States)

Stöggl, Thomas; Kampel, Wolfgang; Müller, Erich; Lindinger, Stefan

2010-01-01

The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques. Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed. The double-push skating technique was approximately 4.3% faster (P push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P push technique compared with the V2 technique (all P values push technique compared with the other two techniques (P push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.

Push Off 2000 : new oilfield safety device catching on

Energy Technology Data Exchange (ETDEWEB)

Mowers, J.

2006-12-15

Fuel gas scrubbers use production gas to operate oil batteries, well separators, dehydrators, compressors, and pneumatic and pressure controls. Once an internal float gets stuck, production is stopped. The Push Off 2000 is a new safety device for fuel gas scrubbers which allows operators to easily dislodge a stuck internal float by activating the tool, which is mounted on top of the vessel. The device was developed after an operator suffered burns from a flash explosion that occurred after using a hammer to strike the fuel gas scrubber. The hammer method is the usual method of dealing with stuck internal floats, and can also jeopardize the integrity of the vessel, releasing gas or liquid hydrocarbons into the environment. The Push Off 2000 is expected to reduce costly facility downtime and increase revenue generating production time. Over 50 oil and gas companies have the Push Off 2000 device installed on fuel gas scrubber units at their facilities, and have recognized the safety and economic merits of the tool. The patented device has been approved by the Alberta Boilers Safety Association, the British Columbia Boiler and Elevator Safety Branch, and the Saskatchewan Boiler and Pressure Vessel Safety Unit. 1 fig.

Improved ankle push-off power following cheilectomy for hallux rigidus: a prospective gait analysis study.

Science.gov (United States)

Smith, Sheryl M; Coleman, Scott C; Bacon, Stacy A; Polo, Fabian E; Brodsky, James W

2012-06-01

There is limited objective scientific information on the functional effects of cheilectomy. The purpose of this study was to test the hypothesis that cheilectomy for hallux rigidus improves gait by increasing ankle push-off power. Seventeen patients with symptomatic Stage 1 or Stage 2 hallux rigidus were studied. Pre- and postoperative first metatarsophalangeal (MTP) range of motion and AOFAS hallux scores were recorded. A gait analysis was performed within 4 weeks prior to surgery and repeated at a minimum of 1 year after surgery. Gait analysis was done using a three-dimensional motion capture system and a force platform embedded in a 10-m walkway. Gait velocity sagittal plane ankle range of motion and peak sagittal plane ankle push-off power were analyzed. Following cheilectomy, significant increases were noted for first MTP range of motion and AOFAS hallux score. First MTP motion improved an average of 16.7 degrees, from means of 33.9 degrees preoperatively to 50.6 degrees postoperatively (ppush-off power from 1.71±0.92 W/kg to 2.05±0.75 W/kg (ppush-off power.

The limited role of aquifer heterogeneity on metal reduction in an Atlantic coastal plain determined by push-pull tests

International Nuclear Information System (INIS)

Mailloux, Brian J.; Devlin, Stephanie; Fuller, Mark E.; Onstott, T.C.; De Flaun, Mary F.; Choi, K.-H.; Green-Blum, Maria; Swift, Donald J.P.; McCarthy, John; Dong Hailiang

2007-01-01

Sixty push-pull experiments were conducted to determine the factors controlling Fe(III) and Mn(IV) reduction in a well-characterized, shallow, coastal plain aquifer near Oyster, VA, USA. The five multi-level samplers each equipped with 12 ports sampled a heterogeneous portion of the aquifer from 4.4 to 8m-bgs. Each multi-level sampler (MLS) was injected with groundwater that contained NO 3 - and Br - along with: (1) just groundwater (control treatment), (2) humics, (3) lactate (conducted twice) and (4) lactate plus humics. Microbially mediated Fe(III) reduction caused the aqueous Fe Tot concentrations to increase at every depth in the lactate treatment with significant increases within 1 day even while NO 3 - was present. Little change in the Fe Tot concentrations were observed in the control and humics treatment. Humics may have acted as an electron shuttle to increase Fe(III) reduction in the lactate plus humics treatment. The amount of Mn(IV) reduction was significantly lower than that of Fe(III) reduction. Geochemical modeling indicated that gas formation, sorption on reactive surfaces, and mineral precipitation were important processes and that Fe(III) and SO 4 2- reduction were co-occurring. Conditions were favorable for the precipitation of Fe-carbonates, Fe-sulfides and Fe-silicates. In the lactate treatment protist concentrations increased then decreased and planktonic cell concentrations steadily increased, whereas no change was observed in the control treatment. Correlations of Fe(III) reduction with physical and chemical heterogeneity were weak, probably as a result of the abundance of Fe(III) bearing minerals relative to electron donor abundance and that the push-pull test sampled a representative elemental volume that encompassed the microbial diversity within the aquifer. This work indicates that stimulating metal reduction in aquifer systems is a feasible method for remediating heterogeneous subsurface sites contaminated with metals and

Three components of postural control associated with pushing in symmetrical and asymmetrical stance.

Science.gov (United States)

Lee, Yun-Ju; Aruin, Alexander S

2013-07-01

A number of occupational and leisure activities that involve pushing are performed in symmetrical or asymmetrical stance. The goal of this study was to investigate early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs) during pushing performed while standing. Ten healthy volunteers stood in symmetrical stance (with feet parallel) or in asymmetrical stance (staggered stance with one foot forward) and were instructed to use both hands to push forward the handle of a pendulum attached to the ceiling. Bilateral EMG activity of the trunk and leg muscles and the center of pressure (COP) displacements in the anterior-posterior (AP) and medial-lateral (ML) directions were recorded and analyzed during the EPAs, APAs, and CPAs. The EMG activity and the COP displacement were different between the symmetrical and asymmetrical stance conditions. The COP displacements in the ML direction were significantly larger in staggered stance than in symmetrical stance. In staggered stance, the EPAs and APAs in the thigh muscles of the backward leg were significantly larger, and the CPAs were smaller than in the forward leg. There was no difference in the EMG activity of the trunk muscles between the stance conditions. The study outcome confirmed the existence of the three components of postural control (EPAs, APAs, and CPAs) in pushing. Moreover, standing asymmetrically was associated with asymmetrical patterns of EMG activity in the lower extremities reflecting the stance-related postural control during pushing. The study outcome provides a basis for studying postural control during other daily activities involving pushing.

Is perception of vertical impaired in individuals with chronic stroke with a history of 'pushing'?

Science.gov (United States)

Mansfield, Avril; Fraser, Lindsey; Rajachandrakumar, Roshanth; Danells, Cynthia J; Knorr, Svetlana; Campos, Jennifer

2015-03-17

Post-stroke 'pushing' behaviour appears to be caused by impaired perception of vertical in the roll plane. While pushing behaviour typically resolves with stroke recovery, it is not known if misperception of vertical persists. The purpose of this study was to determine if perception of vertical is impaired amongst stroke survivors with a history of pushing behaviour. Fourteen individuals with chronic stroke (7 with history of pushing) and 10 age-matched healthy controls participated. Participants sat upright on a chair surrounded by a curved projection screen in a laboratory mounted on a motion base. Subjective visual vertical (SVV) was assessed using a 30 trial, forced-choice protocol. For each trial participants viewed a line projected on the screen and indicated if the line was tilted to the right or the left. For the subjective postural vertical (SPV), participants wore a blindfold and the motion base was tilted to the left or right by 10-20°. Participants were asked to adjust the angular movements of the motion base until they felt upright. SPV was not different between groups. SVV was significantly more biased towards the contralesional side for participants with history of pushing (-3.6 ± 4.1°) than those without (-0.1 ± 1.4°). Two individuals with history of pushing had SVV or SPV outside the maximum for healthy controls. Impaired vertical perception may persist in some individuals with prior post-stroke pushing, despite resolution of pushing behaviours, which could have consequences for functional mobility and falls. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

40 CFR 63.7323 - What procedures must I use to establish operating limits?

Science.gov (United States)

2010-07-01

... use to establish operating limits? (a) For a venturi scrubber applied to pushing emissions from a coke oven battery, you must establish site-specific operating limits for pressure drop and scrubber water... that meet the emission limit. (e) You may change the operating limit for a venturi scrubber, capture...

The influence of push-off timing in a robotic ankle-foot prosthesis on the energetics and mechanics of walking.

Science.gov (United States)

Malcolm, Philippe; Quesada, Roberto E; Caputo, Joshua M; Collins, Steven H

2015-02-22

Robotic ankle-foot prostheses that provide net positive push-off work can reduce the metabolic rate of walking for individuals with amputation, but benefits might be sensitive to push-off timing. Simple walking models suggest that preemptive push-off reduces center-of-mass work, possibly reducing metabolic rate. Studies with bilateral exoskeletons have found that push-off beginning before leading leg contact minimizes metabolic rate, but timing was not varied independently from push-off work, and the effects of push-off timing on biomechanics were not measured. Most lower-limb amputations are unilateral, which could also affect optimal timing. The goal of this study was to vary the timing of positive prosthesis push-off work in isolation and measure the effects on energetics, mechanics and muscle activity. We tested 10 able-bodied participants walking on a treadmill at 1.25 m · s(-1). Participants wore a tethered ankle-foot prosthesis emulator on one leg using a rigid boot adapter. We programmed the prosthesis to apply torque bursts that began between 46% and 56% of stride in different conditions. We iteratively adjusted torque magnitude to maintain constant net positive push-off work. When push-off began at or after leading leg contact, metabolic rate was about 10% lower than in a condition with Spring-like prosthesis behavior. When push-off began before leading leg contact, metabolic rate was not different from the Spring-like condition. Early push-off led to increased prosthesis-side vastus medialis and biceps femoris activity during push-off and increased variability in step length and prosthesis loading during push-off. Prosthesis push-off timing had no influence on intact-side leg center-of-mass collision work. Prosthesis push-off timing, isolated from push-off work, strongly affected metabolic rate, with optimal timing at or after intact-side heel contact. Increased thigh muscle activation and increased human variability appear to have caused the lack

Soft robot design methodology for `push-button' manufacturing

Science.gov (United States)

Paik, Jamie

2018-06-01

`Push-button' or fully automated manufacturing would enable the production of robots with zero intervention from human hands. Realizing this utopia requires a fundamental shift from a sequential (design-materials-manufacturing) to a concurrent design methodology.

Positive Harris recurrence and diffusion scale analysis of a push pull queueing network

NARCIS (Netherlands)

Nazarathy, J.; Weiss, G.

2010-01-01

We consider a push pull queueing network with two servers and two types of job which are processed by the two servers in opposite order, with stochastic generally distributed processing times. This push pull network was introduced by Kopzon and Weiss, who assumed exponential processing times. It is

Operant Conditioning in Honey Bees (Apis mellifera L.): The Cap Pushing Response.

Science.gov (United States)

Abramson, Charles I; Dinges, Christopher W; Wells, Harrington

2016-01-01

The honey bee has been an important model organism for studying learning and memory. More recently, the honey bee has become a valuable model to understand perception and cognition. However, the techniques used to explore psychological phenomena in honey bees have been limited to only a few primary methodologies such as the proboscis extension reflex, sting extension reflex, and free flying target discrimination-tasks. Methods to explore operant conditioning in bees and other invertebrates are not as varied as with vertebrates. This may be due to the availability of a suitable response requirement. In this manuscript we offer a new method to explore operant conditioning in honey bees: the cap pushing response (CPR). We used the CPR to test for difference in learning curves between novel auto-shaping and more traditional explicit-shaping. The CPR protocol requires bees to exhibit a novel behavior by pushing a cap to uncover a food source. Using the CPR protocol we tested the effects of both explicit-shaping and auto-shaping techniques on operant conditioning. The goodness of fit and lack of fit of these data to the Rescorla-Wagner learning-curve model, widely used in classical conditioning studies, was tested. The model fit well to both control and explicit-shaping results, but only for a limited number of trials. Learning ceased rather than continuing to asymptotically approach the physiological most accurate possible. Rate of learning differed between shaped and control bee treatments. Learning rate was about 3 times faster for shaped bees, but for all measures of proficiency control and shaped bees reached the same level. Auto-shaped bees showed one-trial learning rather than the asymptotic approach to a maximal efficiency. However, in terms of return-time, the auto-shaped bees' learning did not carry over to the covered-well test treatments.

[Autoshaping of a button-push response and eye movement in human subjects].

Science.gov (United States)

Kimura, H; Fukui, I; Inaki, K

1990-12-01

Two experiments were conducted with human subjects to investigate the similarities and differences between animal and human behaviors under autoshaping procedures. In these experiments, light served as CS, and display on TV served as US. Whether the pushing button response or gazing response to CS could be obtained in human subjects under Pavlovian conditioning procedure was examined. In Experiment 1, uninstructed naive subjects were placed in a room containing a push-button and a TV display. Within the experimental sessions, the push-button was lit for 8 s as CS, and then paired with the display of a soft pornographic program on TV for 10 s. The result indicated that the modeling of pushing button promoted the increase of response probability among the subjects. The trials conducted after the rest period indicated an increase of response probability. In Experiment 2, a 4 cm square translucent panel was lit for 20 s as CS, and then paired with the display of a computer graphic picture on TV for 8 s as US. Some subjects started gazing at the CS for several seconds. These results indicated that some subjects could acquire the gazing response under the autoshaping procedure.

Benchtop-magnetic resonance imaging (BT-MRI) characterization of push-pull osmotic controlled release systems.

Science.gov (United States)

Malaterre, Vincent; Metz, Hendrik; Ogorka, Joerg; Gurny, Robert; Loggia, Nicoletta; Mäder, Karsten

2009-01-05

The mechanism of drug release from push-pull osmotic systems (PPOS) has been investigated by Magnetic Resonance Imaging (MRI) using a new benchtop apparatus. The signal intensity profiles of both PPOS layers were monitored non-invasively over time to characterize the hydration and swelling kinetics. The drug release performance was well-correlated to the hydration kinetics. The results show that (i) hydration and swelling critically depend on the tablet core composition, (ii) high osmotic pressure developed by the push layer may lead to bypassing the drug layer and incomplete drug release and (iii) the hydration of both the drug and the push layers needs to be properly balanced to efficiently deliver the drug. MRI is therefore a powerful tool to get insights on the drug delivery mechanism of push-pull osmotic systems, which enable a more efficient optimization of such formulations.

Biomechanical comparison of the double-push technique and the conventional skate skiing technique in cross-country sprint skiing.

Science.gov (United States)

Stöggl, Thomas; Müller, Erich; Lindinger, Stefan

2008-09-01

The aims of the study were to: (1) adapt the "double-push" technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional "V2" skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 +/- 2.2% faster (P push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique.

Exploratory system dynamics : A directed search for limits to global water use

NARCIS (Netherlands)

Kwakkel, J.H.; Timmermans, J.S.

2012-01-01

Rockström et al. (2009) introduced the concept of a safe operating space for humanity that will not push the planet out of the ‘Holocene state’. These limits are being investigated for various earth bound systems. Estimates of these limits are plagued by uncertainty. In case of the limits to the

Cart pushing: the effect of magnitude and direction of push force, and of trunk inclination on low back loading

NARCIS (Netherlands)

Hoozemans, M.J.M.; Faber, G.S.; Slaghuis, W.; van Dieen, J.H.

2007-01-01

The primary objective of the present study was to quantify the relative effect of the magnitude and direction of the exerted push force and of trunk inclination on the mechanical load at the low back using a regression analysis for correlated data. In addition, we explored the effects of handle

Gender comparison of psychophysical forces, cardiopulmonary, and muscle metabolic responses during a simulated cart pushing task.

Science.gov (United States)

Maikala, Rammohan V; Ciriello, Vincent M; Dempsey, Patrick G; O'Brien, Niall V

2010-10-01

The purpose was to compare psychophysiological responses between healthy male and female workers during dynamic pushing. Using a psychophysical approach, 27 participants chose an acceptable force that they could push over a 7.6m distance at a frequency of 1 push per min on a treadmill. On a separate day, cardiopulmonary (e.g., whole-body oxygen uptake, heart rate, ventilation volume) and muscle metabolic measurements (change in muscle blood volume [ΔtHb] and Tissue Oxygenation Index [TOI]) from the right and left gastrocnemius muscles were collected simultaneously while participants pushed the previously chosen acceptable force on the treadmill at a similar frequency and distance for 2h. Results showed no significant difference between men and women for integrated force exerted on the instrumented treadmill handle and cardiopulmonary responses. In contrast, women demonstrated 45.7% lower ΔtHb but 3.6% higher TOI in the gastrocnemius region as compared to men, suggesting a lower hemoglobin concentration in women and high venous oxygen saturation during pushing. When ΔtHb and TOI were corrected for both body mass and pushing force, the disparity in gender was retained, implying an increased muscle oxygen saturation per force development in women than men during pushing. In the left gastrocnemius region, ΔtHb was 60% lower and TOI was 5.7% higher in women than men, suggesting an uneven muscle loading during pushing. Overall, the gender similarity in cardiopulmonary responses versus disparity in muscle metabolic responses suggest the importance of evaluating human performance during physical work at both whole-body and localized muscle levels. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparative evaluation of the regional micro-push-out bond strength of custom-made resin post system with a prefabricated resin post: An in vitro study

Directory of Open Access Journals (Sweden)

S Ranjithkumar

2012-01-01

Conclusion : Within the limitations of the study, amongst all the four groups tested, custom-made resin post luted with self-etch system (CMPR-SE showed higher micro-push-out bond strength values in all regions when compared to the other groups

Immediate compared with delayed pushing in the second stage of labor: a systematic review and meta-analysis.

Science.gov (United States)

Tuuli, Methodius G; Frey, Heather A; Odibo, Anthony O; Macones, George A; Cahill, Alison G

2012-09-01

To estimate whether immediate or delayed pushing in the second stage of labor optimizes spontaneous vaginal delivery and other perinatal outcomes. We searched electronic databases MEDLINE and CINHAL through August 2011 without restrictions. The search terms used were MeSH headings, text words, and word variations of the words or phrases labor, laboring down, passive descent, passive second stage, physiologic second stage, spontaneous pushing, pushing, or bearing down. We searched for randomized controlled trials comparing immediate with delayed pushing in the second stage of labor. The primary outcome was spontaneous vaginal delivery. Secondary outcomes were instrumental delivery, cesarean delivery, duration of the second stage, duration of active pushing, and other maternal and neonatal outcomes. Heterogeneity was assessed using the Q test and I2. Pooled relative risks (RRs) and weighted mean differences were calculated using random-effects models. Twelve randomized controlled trials (1,584 immediate and 1,531 delayed pushing) met inclusion criteria. Overall, delayed pushing was associated with an increased rate of spontaneous vaginal delivery compared with immediate pushing (61.5% compared with 56.9%, pooled RR 1.09, 95% confidence interval [CI] 1.03-1.15). This increase was smaller and not statistically significant among high-quality studies (59.0% compared with 54.9%, pooled RR 1.07, 95% CI 0.98-1.26) but larger and statistically significant in lower-quality studies (81.0% compared with 71.0%%, pooled RR 1.13, 95% CI 1.02-1.24). Operative vaginal delivery rates were high in most studies and not significantly different between the two groups (33.7% compared with 37.4%, pooled RR 0.89, 95% CI 0.76-1.06). Delayed pushing was associated with prolongation of the second stage (weighted mean difference 56.92 minutes, 95% CI 42.19-71.64) and shortened duration of active pushing (weighted mean difference -21.98 minutes, 95% CI -31.29 to -12.68). Studies to date suggest

Development of a direct push based in-situ thermal conductivity measurement system

Science.gov (United States)

Chirla, Marian Andrei; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

2016-04-01

Heat pump systems are commonly utilized in Europe, for the exploitation of the shallow geothermal potential. To guarantee a sustainable use of the geothermal heat pump systems by saving resources and minimizing potential negative impacts induced by temperature changes within soil and groundwater, new geothermal exploration methods and tools are required. The knowledge of the underground thermal properties is a necessity for a correct and optimum design of borehole heat exchangers. The most important parameter that indicates the performance of the systems is thermal conductivity of the ground. Mapping the spatial variability of thermal conductivity, with high resolution in the shallow subsurface for geothermal purposes, requires a high degree of technical effort to procure adequate samples for thermal analysis. A collection of such samples from the soil can disturb sample structure, so great care must be taken during collection to avoid this. Factors such as transportation and sample storage can also influence measurement results. The use of technologies like Thermal Response Test (TRT) require complex mechanical and electrical systems for convective heat transport in the subsurface and longer monitoring times, often three days. Finally, by using thermal response tests, often only one integral value is obtained for the entire coupled subsurface with the borehole heat exchanger. The common thermal conductivity measurement systems (thermal analyzers) can perform vertical thermal conductivity logs only with the aid of sample procurement, or by integration into a drilling system. However, thermal conductivity measurements using direct push with this type of probes are not possible, due to physical and mechanical limitations. Applying vertical forces using direct push technology, in order to penetrate the shallow subsurface, can damage the probe and the sensors systems. The aim of this study is to develop a new, robust thermal conductivity measurement probe, for direct

Direct-push geochemical profiling for assessment of inorganic chemical heterogeneity in aquifers

Science.gov (United States)

Schulmeister, M.K.; Healey, J.M.; Butler, J.J.; McCall, G.W.

2004-01-01

Discrete-depth sampling of inorganic groundwater chemistry is essential for a variety of site characterization activities. Although the mobility and rapid sampling capabilities of direct-push techniques have led to their widespread use for evaluating the distribution of organic contaminants, complementary methods for the characterization of spatial variations in geochemical conditions have not been developed. In this study, a direct-push-based approach for high-resolution inorganic chemical profiling was developed at a site where sharp chemical contrasts and iron-reducing conditions had previously been observed. Existing multilevel samplers (MLSs) that span a fining-upward alluvial sequence were used for comparison with the direct-push profiling. Chemical profiles obtained with a conventional direct-push exposed-screen sampler differed from those obtained with an adjacent MLS because of sampler reactivity and mixing with water from previous sampling levels. The sampler was modified by replacing steel sampling components with stainless-steel and heat-treated parts, and adding an adapter that prevents mixing. Profiles obtained with the modified approach were in excellent agreement with those obtained from an adjacent MLS for all constituents and parameters monitored (Cl, NO3, Fe, Mn, DO, ORP, specific conductance and pH). Interpretations of site redox conditions based on field-measured parameters were supported by laboratory analysis of dissolved Fe. The discrete-depth capability of this approach allows inorganic chemical variations to be described at a level of detail that has rarely been possible. When combined with the mobility afforded by direct-push rigs and on-site methods of chemical analysis, the new approach is well suited for a variety of interactive site-characterization endeavors. ?? 2003 Elsevier B.V. All rights reserved.

Effects of a pushing intervention on pain, fatigue and birthing experiences among Taiwanese women during the second stage of labour.

Science.gov (United States)

Chang, Su-Chuan; Chou, Min-Min; Lin, Kuan-Chia; Lin, Lie-Chu; Lin, Yu-Lan; Kuo, Su-Chen

2011-12-01

To evaluate maternal labour pain, fatigue, duration of the second stage of labour, the women's bearing-down experiences and the newborn infant Apgar scores when spontaneous pushing is used in an upright position. Quasi-experimental study. Medical centre in Taichung, Taiwan. 66 Women giving birth at the hospital, with 33 primigravidas assigned to each group. During the second stage of labour, the women in the experimental group pushed from an upright position and were given support to push spontaneously; the women in the control group pushed from a supine position and were supported via Valsalva pushing. Pain scores were recorded at two evaluation time points: at 10 cm of cervical dilation and one hour after the first pain score evaluation. One to four hours after childbirth, the trained nurses collected the fatigue and pushing experience scores. The women in the experimental group had a lower pain index (5.67 versus 7.15, p = 0.01), lower feelings of fatigue post birth (53.91 versus 69.39, p pushing intervention during the second stage of labour lessened pain and fatigue, shortened the pushing time and enhanced the pushing experience. Pushing interventions can yield increased satisfaction levels for women giving birth. Copyright © 2010 Elsevier Ltd. All rights reserved.

Targeted Drug Delivery in the Suprachoroidal Space by Swollen Hydrogel Pushing

Science.gov (United States)

Jung, Jae Hwan; Desit, Patcharin; Prausnitz, Mark R.

2018-01-01

Purpose The purpose is to target model drug particles to the posterior region of the suprachoroidal space (SCS) of the eye controlled via pushing by hydrogel swelling. Methods A particle formulation containing 1% hyaluronic acid (HA) with fluorescent polymer particles and a hydrogel formulation containing 4% HA were introduced in a single syringe as two layers without mixing, and injected sequentially into the SCS of the rabbit eye ex vivo and in vivo using a microneedle. Distribution of particles in the eye was determined by microscopy. Results During injection, the particle formulation was pushed toward the middle of the SCS by the viscous hydrogel formulation, but less than 12% of particles reached the posterior SCS. After injection, the particle formulation was pushed further toward the macula and optic nerve in the posterior SCS by hydrogel swelling and spreading. Heating the eye to 37°C, or injecting in vivo decreased viscosity and mechanical strength of the hydrogel, thereby allowing it to swell and flow further in the SCS. A high salt concentration (9% NaCl) in the hydrogel formulation further increased hydrogel swelling due to osmotic flow into the hydrogel. In this way, up to 76% of particles were delivered to the posterior SCS from an injection made near the limbus. Conclusions This study shows that model drug particles can be targeted to the posterior SCS by HA hydrogel swelling and pushing without particle functionalization or administering external driving forces. PMID:29677369

Targeted Drug Delivery in the Suprachoroidal Space by Swollen Hydrogel Pushing.

Science.gov (United States)

Jung, Jae Hwan; Desit, Patcharin; Prausnitz, Mark R

2018-04-01

The purpose is to target model drug particles to the posterior region of the suprachoroidal space (SCS) of the eye controlled via pushing by hydrogel swelling. A particle formulation containing 1% hyaluronic acid (HA) with fluorescent polymer particles and a hydrogel formulation containing 4% HA were introduced in a single syringe as two layers without mixing, and injected sequentially into the SCS of the rabbit eye ex vivo and in vivo using a microneedle. Distribution of particles in the eye was determined by microscopy. During injection, the particle formulation was pushed toward the middle of the SCS by the viscous hydrogel formulation, but less than 12% of particles reached the posterior SCS. After injection, the particle formulation was pushed further toward the macula and optic nerve in the posterior SCS by hydrogel swelling and spreading. Heating the eye to 37°C, or injecting in vivo decreased viscosity and mechanical strength of the hydrogel, thereby allowing it to swell and flow further in the SCS. A high salt concentration (9% NaCl) in the hydrogel formulation further increased hydrogel swelling due to osmotic flow into the hydrogel. In this way, up to 76% of particles were delivered to the posterior SCS from an injection made near the limbus. This study shows that model drug particles can be targeted to the posterior SCS by HA hydrogel swelling and pushing without particle functionalization or administering external driving forces.

La Push, Washington Tsunami Forecast Grids for MOST Model

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The La Push, Washington Forecast Model Grids provides bathymetric data strictly for tsunami inundation modeling with the Method of Splitting Tsunami (MOST) model....

Prosthetic ankle push-off work reduces metabolic rate but not collision work in non-amputee walking

Science.gov (United States)

Caputo, Joshua M.; Collins, Steven H.

2014-12-01

Individuals with unilateral below-knee amputation expend more energy than non-amputees during walking and exhibit reduced push-off work and increased hip work in the affected limb. Simple dynamic models of walking suggest a possible solution, predicting that increasing prosthetic ankle push-off should decrease leading limb collision, thereby reducing overall energy requirements. We conducted a rigorous experimental test of this idea wherein ankle-foot prosthesis push-off work was incrementally varied in isolation from one-half to two-times normal levels while subjects with simulated amputation walked on a treadmill at 1.25 m.s-1. Increased prosthesis push-off significantly reduced metabolic energy expenditure, with a 14% reduction at maximum prosthesis work. In contrast to model predictions, however, collision losses were unchanged, while hip work during swing initiation was decreased. This suggests that powered ankle push-off reduces walking effort primarily through other mechanisms, such as assisting leg swing, which would be better understood using more complete neuromuscular models.

Duration of Second Stage of Labour at Term and Pushing Time: Risk Factors for Postpartum Haemorrhage.

Science.gov (United States)

Looft, Emelie; Simic, Marija; Ahlberg, Mia; Snowden, Jonathan M; Cheng, Yvonne W; Stephansson, Olof

2017-03-01

Prolonged labour is associated with increased risk of postpartum haemorrhage (PPH), but the role of active pushing time and the relation with management during labour remains poorly understood. A population-based cohort study from electronic medical record data in the Stockholm-Gotland Region, Sweden. We included 57 267 primiparous women with singleton, term gestation, livebirths delivered vaginally in cephalic presentation in 2008-14. We performed multivariable Poisson regression to estimate the association between length of second stage, pushing time, and PPH (estimated blood loss >500 mL during delivery), adjusting for maternal, delivery, and fetal characteristics as potential confounders. The incidence of PPH was 28.9%. The risk of PPH increased with each passing hour of second stage: compared with a second stage pushing time exceeding 30 min. Compared to pushing time between 15 and 29 min, the RR for PPH were for pushing time during labour are both associated with increased risk of PPH. © 2017 John Wiley & Sons Ltd.

Lower limb joint kinetics and ankle joint stiffness in the sprint start push-off.

Science.gov (United States)

Charalambous, Laura; Irwin, Gareth; Bezodis, Ian N; Kerwin, David

2012-01-01

Sprint push-off technique is fundamental to sprint performance and joint stiffness has been identified as a performance-related variable during dynamic movements. However, joint stiffness for the push-off and its relationship with performance (times and velocities) has not been reported. The aim of this study was to quantify and explain lower limb net joint moments and mechanical powers, and ankle stiffness during the first stance phase of the push-off. One elite sprinter performed 10 maximal sprint starts. An automatic motion analysis system (CODA, 200 Hz) with synchronized force plates (Kistler, 1000 Hz) collected kinematic profiles at the hip, knee, and ankle and ground reaction forces, providing input for inverse dynamics analyses. The lower-limb joints predominately extended and revealed a proximal-to-distal sequential pattern of maximal extensor angular velocity and positive power production. Pearson correlations revealed relationships (P push-off in different ways, depending on the phase of stance considered.

Rotational foot placement specifies the lever arm of the ground reaction force during the push-off phase of walking initiation.

Science.gov (United States)

Erdemir, Ahmet; Piazza, Stephen J

2002-06-01

The lever arm of the ground reaction force (GRF) about the talocrural joint axis is a functionally important indicator of the nature of foot loading. Walking initiation experiments (ten subjects; age, 23-29 years) were completed to demonstrate that rotational foot placement is a possible strategy to specify the lever arm. Externally-rotated foot placement resulted in larger lever arms during push-off. A computer simulation of push-off revealed that a decreased lever arm reduces the plantarflexion moment necessary to maintain a constant forward velocity, while increasing the required plantarflexion velocity. Shortening of the foot thus diminishes the muscular force demand but also requires high muscle fiber shortening velocities that may limit the force generating capacity of plantar flexors. Decreased plantar flexion moment and slow walking previously noted in partial-foot amputees may result from shortened lever arms in this manner.

Modelling a technology push by using hybrid franchising

NARCIS (Netherlands)

Fredriks, Jan; Pennink, Bartjan; Simaputang, T.; Siswanto, J.

2014-01-01

Introducing a technology push to stimulate entrepreneurship in remote areas in developing countries can be examined in the context of a franchising model (social or commercial franchising). The results of this study (fieldwork in Kalimantan, Indonesia) point to a high feasibility of introducing a

Optimal Halbach Permanent Magnet Designs for Maximally Pulling and Pushing Nanoparticles.

Science.gov (United States)

Sarwar, A; Nemirovski, A; Shapiro, B

2012-03-01

Optimization methods are presented to design Halbach arrays to maximize the forces applied on magnetic nanoparticles at deep tissue locations. In magnetic drug targeting, where magnets are used to focus therapeutic nanoparticles to disease locations, the sharp fall off of magnetic fields and forces with distances from magnets has limited the depth of targeting. Creating stronger forces at depth by optimally designed Halbach arrays would allow treatment of a wider class of patients, e.g. patients with deeper tumors. The presented optimization methods are based on semi-definite quadratic programming, yield provably globally optimal Halbach designs in 2 and 3-dimensions, for maximal pull or push magnetic forces (stronger pull forces can collect nano-particles against blood forces in deeper vessels; push forces can be used to inject particles into precise locations, e.g. into the inner ear). These Halbach designs, here tested in simulations of Maxwell's equations, significantly outperform benchmark magnets of the same size and strength. For example, a 3-dimensional 36 element 2000 cm(3) volume optimal Halbach design yields a ×5 greater force at a 10 cm depth compared to a uniformly magnetized magnet of the same size and strength. The designed arrays should be feasible to construct, as they have a similar strength (≤ 1 Tesla), size (≤ 2000 cm(3)), and number of elements (≤ 36) as previously demonstrated arrays, and retain good performance for reasonable manufacturing errors (element magnetization direction errors ≤ 5°), thus yielding practical designs to improve magnetic drug targeting treatment depths.

Removal of Airborne Contaminants from a Surface Tank by a Push-Pull System

DEFF Research Database (Denmark)

Heiselberg, Per; Topp, Claus

Open surface tanks are used in many industrial processes, and local exhaust systems are often designed to capture and remove toxic fumes diffused from materials in the tanks prior to their escape into the workplace environment. The push-pull system seems to be the most efficient local exhaust...... system, but proper design is required to ensure health and safety of the workers and, furthermore, it is very desirable from an energy conservation point of view to determine an optimum and -an efficient design of push-pull hoods which can exhaust all contaminants with a minimum quantity of volume flow....... The paper describes and discusses different design methods and compares designed values with results from a measurement series of push-pull system efficiency....

Gait strategy changes with acceleration to accommodate the biomechanical constraint on push-off propulsion.

Science.gov (United States)

Oh, Keonyoung; Baek, Juhyun; Park, Sukyung

2012-11-15

To maintain steady and level walking, push-off propulsion during the double support phase compensates for the energy loss through heel strike collisions in an energetically optimal manner. However, a large portion of daily gait activities also contains transient gait responses, such as acceleration or deceleration, during which the observed dominance of the push-off work or the energy optimality may not hold. In this study, we examined whether the push-off propulsion during the double support phase served as a major energy source for gait acceleration, and we also studied the energetic optimality of accelerated gait using a simple bipedal walking model. Seven healthy young subjects participated in the over-ground walking experiments. The subjects walked at four different constant gait speeds ranging from a self-selected speed to a maximum gait speed, and then they accelerated their gait from zero to the maximum gait speed using a self-selected acceleration ratio. We measured the ground reaction force (GRF) of three consecutive steps and the corresponding leg configuration using force platforms and an optical marker system, respectively, and we compared the mechanical work performed by the GRF during each single and double support phase. In contrast to the model prediction of an increase in the push-off propulsion that is proportional to the acceleration and minimizes the mechanical energy cost, the push-off propulsion was slightly increased, and a significant increase in the mechanical work during the single support phase was observed. The results suggest that gait acceleration occurs while accommodating a feasible push-off propulsion constraint. Copyright © 2012 Elsevier Ltd. All rights reserved.

Discussion of push-pull equilibrium in well field at Yining in-situ leaching mine, Xinjiang

International Nuclear Information System (INIS)

Wang Haifeng; Su Xuebin

1999-01-01

Combined with a case of in-situ leaching project, the author discusses the principle and approaches for push-pull equilibrium controlling, and gives the suggestions solving the un-equilibrium problems of push-pull in well field during operation

Prosthetic ankle push-off work reduces metabolic rate but not collision work in non-amputee walking

OpenAIRE

Caputo, Joshua M.; Collins, Steven H.

2014-01-01

Individuals with unilateral below-knee amputation expend more energy than non-amputees during walking and exhibit reduced push-off work and increased hip work in the affected limb. Simple dynamic models of walking suggest a possible solution, predicting that increasing prosthetic ankle push-off should decrease leading limb collision, thereby reducing overall energy requirements. We conducted a rigorous experimental test of this idea wherein ankle-foot prosthesis push-off work was incrementall...

Isolated and combined effects of asymmetric stance and pushing movement on the anticipatory and compensatory postural control.

Science.gov (United States)

Lee, Yun-Ju; Aruin, Alexander S

2014-04-01

To investigate effects of symmetric and asymmetric stance and pushing movement on anticipatory and compensatory postural adjustments (APAs and CPAs). Ten healthy volunteers stood symmetrically (feet parallel) or asymmetrically (one foot forward and the other backward) and pushed a handle with both hands or right or left hand. Bilateral EMG activity of the trunk and leg muscles and center of pressure (COP) displacements in the anterior-posterior (AP) and medial-lateral (ML) directions were recorded and analyzed during the APAs and CPAs. Isolated asymmetry of stance was associated with larger muscle activity of the backward leg while isolated asymmetry of pushing movement induced larger trunk muscle activity on the contralateral side. A combined asymmetry of stance and pushing movement resulted in the increase or decrease of the thigh muscle activity and ML COP displacement depending on whether both asymmetries were induced on the same side of the body or on opposite sides. Both isolated and combined asymmetries affect APAs and CPAs in pushing. Using combined asymmetry of stance and arm movement might be beneficial in performing pushing activity. The outcome of the study provides a basis for studying postural control in individuals with unilateral impairment while performing daily tasks involving pushing. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Calidad de vida y cicatrización en pacientes con úlceras de etiología venosa: Validación del Charing Cross Venous Ulcer Questionnaire, versión española (CCVUQ-e y del Pressure Ulcer Scale for Healing, versión española (PUSH-e. Resultados preliminares Quality of life healing in patints with venous ulcers of etiology: Validation of Charing Cross Venous Ulcer Questionnaire, Spanish version (CCVUQ-e and the Pressure Ulcer Scale for Healing, Spanish version (PUSH-e. Preliminary results

Directory of Open Access Journals (Sweden)

Renata Virgina González-Consuegra

2011-09-01

correlación entre el CCVUQ-e y el PUSH-e al inicio fue r = 0,49 (p Introduction: in Spain, there is no specific measurement instruments for Health Related Quality of Life (HRQOL and to measuring progress towards healing in patients with chronic wounds that have been validated by research. Having these tools will help the decision-making and improve the quality of care to these patients. Thus, the objectives of this study are: to validate and establish the psychometric properties in Spanish, for "Charing Cross Venous Ulcer Questionnaire (CCVUQ-e" to measure HRQOL in patients with venous ulcers (UV and to validate and establish Clinical-metric properties, in Spanish, for "Pressure Ulcer Scale for Healing (PUSH-e" in the same sample. And, to establish what is the HRQOL of patients in the study sample. Methods: prospective validation of instruments, with a repeated measures model. A estimated sample of 105 patients were selected according to international standard for validating questionnaires. Procedure: for a period of 6 weeks, patients were studied every 2 weeks, collecting variables related to demography, status of disease, ulcers, HRQOL data through the questionnaire CCVUQ-e and SF-12 V2, treatments and healing data trough PUSH-e. Analysis: calculation of psychometric indicators and metrics for measuring clinical validity, reliability and sensitivity to change of such instruments. Descriptive statistics of the variables studied. Comparisons of outcome variables. Results: preliminary results of the study with data from 27 patients with UV. The sample contains all the characteristics of patients with UV. Preliminarily, the CCUVQ-e shows good internal consistency (Cronbach alpha > 0.80. The correlation between CCVUQ-e and PUSH-e at baseline was r = 0.49 (P < 0.001 and at the end of the study was r = 0.64 (p = 0.006. Sensitivity to change of instruments, as with repeated measures model, is statistically significant (p < 0.001. Conclusions: preliminary results show, in both

The Transnational State and the Infrastructure Push

DEFF Research Database (Denmark)

Ougaard, Morten

2018-01-01

In 2010, the G20, in cooperation with major international organisations, launched a comprehensive effort – here labelled the infrastructure push – to promote infrastructure investments around the world. Using selected transnationalised elements from historical materialism, this is explained as a ....... In this cooperation, the international organisations have a relatively autonomous role in line with a historical materialist understanding of state apparatuses....

The Transnational State and the Infrastructure Push

DEFF Research Database (Denmark)

Ougaard, Morten

In 2010 the G20 in cooperation with major international organizations launched a comprehensive effort - here labelled the infrastructure push – to promote infrastructure investments around the world. Using selected transnationalised elements from historical materialism, this is explained as a tra....... In this cooperation, the international organizations have a relatively autonomous role in line with a historical materialist understanding of state apparatuses....

Femtosecond Pump-Push-Probe and Pump-Dump-Probe Spectroscopy of Conjugated Polymers: New Insight and Opportunities.

Science.gov (United States)

Kee, Tak W

2014-09-18

Conjugated polymers are an important class of soft materials that exhibit a wide range of applications. The excited states of conjugated polymers, often referred to as excitons, can either deactivate to yield the ground state or dissociate in the presence of an electron acceptor to form charge carriers. These interesting properties give rise to their luminescence and the photovoltaic effect. Femtosecond spectroscopy is a crucial tool for studying conjugated polymers. Recently, more elaborate experimental configurations utilizing three optical pulses, namely, pump-push-probe and pump-dump-probe, have been employed to investigate the properties of excitons and charge-transfer states of conjugated polymers. These studies have revealed new insight into femtosecond torsional relaxation and detrapping of bound charge pairs of conjugated polymers. This Perspective highlights (1) the recent achievements by several research groups in using pump-push-probe and pump-dump-probe spectroscopy to study conjugated polymers and (2) future opportunities and potential challenges of these techniques.

Safety analysis for push-mode and rotary-mode core sampling

International Nuclear Information System (INIS)

Milliken, N.J.; Geschke, G.R.

1995-01-01

This safety analysis analyzes using the push-mode core sampling truck in the push-mode and the rotary-mode core sampling trucks in both the push- and rotary-modes to retrieve core samples that, once taken and analyzed, will yield waste characterization data for the hazardous waste tanks at the Hanford Site. Operation of the core sampling trucks in both the push- and rotary-modes was reviewed to determine whether the release of radioactive materials could occur during operation. It was concluded that there are three credible scenarios: a sample spill outside of the tank, a steam release event, and an unfiltered release to the environment during continuous exhauster operation. The probability of a sample spill was found to be 10 -4 /event, the probability of a steam release event was determined to fall in the unlikely range (10 -2 /event to 10 -4 /event), and the probability of an unfiltered release was calculated to be 5 x 10 -3 /year. Typically, events with probabilities of 10 -6 /event or less are not considered to be risk significant, and the consequences usually are not analyzed. The three accident scenarios were analyzed to calculate the dose consequences. It was determined that the steam release event is the bounding accident. The onsite and offsite dose consequences for this event are calculated to be 0.24 Sv (24 rem) and 3.2 x 10 -4 Sv (32 mrem), respectively. These consequences are below the risk acceptance guidelines for an unlikely event, as established in WHC-CM-4-46, Nonreactor Facility Safety Analysis Manual. With the design features and the use of the controls presented in Section 8.0, this operation represents a minimal risk

Educational Exclusion: Drop Out, Push Out, and School-to-Prison Pipeline among LGBTQ Youth

Science.gov (United States)

Gay, Lesbian and Straight Education Network (GLSEN), 2016

2016-01-01

"Educational Exclusion: Drop Out, Push Out, and the School-to-Prison Pipeline among LGBTQ Youth" provides an in-depth look at the conditions that effectively push LGBTQ youth out of school and potentially into the criminal justice system. The report provides specific, real world guidance to address the hostile school climates and…

Optical Pushing: A Tool for Parallelized Biomolecule Manipulation

NARCIS (Netherlands)

Sitters, G.; Laurens, N.; de Rijk, E.J.; Kress, H.; Peterman, E.J.G.; Wuite, G.J.L.

2016-01-01

The ability to measure and manipulate single molecules has greatly advanced the field of biophysics. Yet, the addition of more single-molecule tools that enable one to measure in a parallel fashion is important to diversify the questions that can be addressed. Here we present optical pushing (OP), a

Pulse width modulated push-pull driven parallel resonant converter with active free-wheel

Science.gov (United States)

Reass, William A.; Schrank, Louis

2004-06-22

An apparatus and method for high frequency alternating power generation to control kilowatts of supplied power in microseconds. The present invention includes a means for energy storage, push-pull switching means, control electronics, transformer means, resonant circuitry and means for excess energy recovery, all in electrical communication. A push-pull circuit works synchronously with a force commutated free-wheel transistor to provide current pulses to a transformer. A change in the conduction angle of the push-pull circuit changes the amount of energy coupled into the transformer's secondary oscillating circuit, thereby altering the induced secondary resonating voltage. At the end of each pulse, the force commutated free-wheel transistor causes residual excess energy in the primary circuit to be transmitted back to the storage capacitor for later use.

The influence of push-off timing in a robotic ankle-foot prosthesis on the energetics and mechanics of walking

OpenAIRE

Malcolm, Philippe; Quesada, Roberto E; Caputo, Joshua M; Collins, Steven H

2015-01-01

Background Robotic ankle-foot prostheses that provide net positive push-off work can reduce the metabolic rate of walking for individuals with amputation, but benefits might be sensitive to push-off timing. Simple walking models suggest that preemptive push-off reduces center-of-mass work, possibly reducing metabolic rate. Studies with bilateral exoskeletons have found that push-off beginning before leading leg contact minimizes metabolic rate, but timing was not varied independently from pus...

Modeling and Simulation of Two Wheelchair Accessories for Pushing Doors.

Science.gov (United States)

Abdullah, Soran Jalal; Shaikh Mohammed, Javeed

2017-03-27

Independent mobility is vital to individuals of all ages, and wheelchairs have proven to be great personal mobility devices. The tasks of opening and navigating through a door are trivial for healthy people, while the same tasks could be difficult for some wheelchair users. A wide range of intelligent wheelchair controllers and systems, robotic arms, or manipulator attachments integrated with wheelchairs have been developed for various applications, including manipulating door knobs. Unfortunately, the intelligent wheelchairs and robotic attachments are not widely available as commercial products. Therefore, the current manuscript presents the modeling and simulation of a novel but simple technology in the form of a passive wheelchair accessory (straight, arm-like with a single wheel, and arc-shaped with multiple wheels) for pushing doors open from a wheelchair. From the simulations using different wheel shapes and sizes, it was found that the arc-shaped accessory could push open the doors faster and with almost half the required force as compared to the arm-like accessory. Also, smaller spherical wheels were found to be best in terms of reaction forces on the wheels. Prototypes based on the arc-shaped accessory design will be manufactured and evaluated for pushing doors open and dodging or gliding other obstacles.

Evaluation of sulfate reduction at experimentally induced mixing interfaces using small-scale push-pull tests in an aquifer-wetland system

International Nuclear Information System (INIS)

Kneeshaw, Tara A.; McGuire, Jennifer T.; Smith, Erik W.; Cozzarelli, Isabelle M.

2007-01-01

This paper presents small-scale push-pull tests designed to evaluate the kinetic controls on SO 4 2- reduction in situ at mixing interfaces between a wetland and aquifer impacted by landfill leachate at the Norman Landfill research site, Norman, OK. Quantifying the rates of redox reactions initiated at interfaces is of great interest because interfaces have been shown to be zones of increased biogeochemical transformations and thus may play an important role in natural attenuation. To mimic the aquifer-wetland interface and evaluate reaction rates, SO 4 2- -rich anaerobic aquifer water (∼100mg/LSO 4 2- ) was introduced into SO 4 2- -depleted wetland porewater via push-pull tests. Results showed SO 4 2- reduction was stimulated by the mixing of these waters and first-order rate coefficients were comparable to those measured in other push-pull studies. However, rate data were complex involving either multiple first-order rate coefficients or a more complex rate order. In addition, a lag phase was observed prior to SO 4 2- reduction that persisted until the mixing interface between test solution and native water was recovered, irrespective of temporal and spatial constraints. The lag phase was not eliminated by the addition of electron donor (acetate) to the injected test solution. Subsequent push-pull tests designed to elucidate the nature of the lag phase support the importance of the mixing interface in controlling terminal electron accepting processes. These data suggest redox reactions may occur rapidly at the mixing interface between injected and native waters but not in the injected bulk water mass. Under these circumstances, push-pull test data should be evaluated to ensure the apparent rate is actually a function of time and that complexities in rate data be considered

PREFACE: Diagnostics for electrical discharge light sources: pushing the limits Diagnostics for electrical discharge light sources: pushing the limits

Science.gov (United States)

Zissis, Georges; Haverlag, Marco

2010-06-01

high to low pressure and dielectric barrier lamps, from breakdown to acoustic resonance. Especially in the domain of high pressure lamps, J J Curry shows how coherent and incoherent x-ray scattering can be used as an imaging technique adapted to lamps. J Hirsch et al treat the acoustic resonance phenomenon that seriously limits the frequency domain for high pressure lamp operation. M Jinno et al illustrate a method that allows for measuring Xe buffer gas pressure in Hg-free metal halide lamps for automotive applications. In the domain of low pressure lamps, M Gendre et al investigate the breakdown phase by means of optical and electrical diagnostic tools. The similarity rules used a long time ago for simulating plasma behaviour based on invariants are now serving as diagnostic tools, as shown in the paper by D Michael et al. N Dagang et al show how impurities can be detected in Hg-free electrodeless lamps and more particularly in dielectric barrier discharges emitting excimer radiation. The quality of light is illustrated by a final example by R Kozakov et al on how to qualify the light output from the lamp with respect to biological effects on humans.

Pushing the limits of signal resolution to make coupling measurement easier.

Science.gov (United States)

Herbert Pucheta, José Enrique; Pitoux, Daisy; Grison, Claire M; Robin, Sylvie; Merlet, Denis; Aitken, David J; Giraud, Nicolas; Farjon, Jonathan

2015-05-07

Probing scalar couplings are essential for structural elucidation in molecular (bio)chemistry. While the measurement of JHH couplings is facilitated by SERF experiments, overcrowded signals represent a significant limitation. Here, a new band selective pure shift SERF allows access to δ(1)H and JHH with an ultrahigh spectral resolution.

Relationship between different push-off variables and start performance in experienced swimmers.

Science.gov (United States)

García-Ramos, Amador; Feriche, Belén; de la Fuente, Blanca; Argüelles-Cienfuegos, Javier; Strojnik, Vojko; Strumbelj, Boro; Štirn, Igor

2015-01-01

The objective of this study was to determine the relationship between different variables measured with a force plate during the swimming start push-off phase and start performance presented by times to 5, 10 and 15 m. Twenty-one women from the Slovenian national swimming team performed two different swim starts (freestyle and undulatory) on a portable force plate to a distance further than 15 m. Correlations between push-off variables and times to 5, 10 and 15 m were quantified through Pearson's product-moment correlation coefficient (r). The variables that significantly correlated (p  .05). Based on the results of this study, we can conclude that horizontal take-off velocity and average horizontal acceleration (calculated as the average horizontal force divided by swimmer's body mass) are the variables most related to swimming start performance in experienced swimmers, and therefore could be the preferred measures to monitor swimmers' efficiency during the push-off phase.

Push-out tests and evaluation of FRP perfobond rib shear connectors performance

Science.gov (United States)

Kolpasky, Ludvik; Ryjacek, Pavel

2017-09-01

The behavioural characteristics of FRP (fibre-reinforced polymer) perfobond rib shear connector was examined through push-out tests in order to verify the applicability for pedestrian bridge structure. The aim of this study is to determine interaction between high performance concrete slab and handmade FRP plate which represent web of the composite beam. Combination of these modern materials leads to structural system with both great load bearing capacity and also sufficient flexural stiffness of the composite element. Openings cut into the GFRP plate at a variable spacing allow GFRP reinforcement bars to be inserted to act as shear studs. Hand lay-up process can increase suitable properties of FRP for connection by perfobond rib shear connectors. In this study, three push-out tests on fiber-reinforced polymer were performed to investigate their shear behaviour. The results of the push-out tests on FRP perfobond rib shear connector indicates great promise for application in full scale structures.

Causal assessment of occupational pushing or pulling and low back pain: results of a systematic review.

Science.gov (United States)

Roffey, Darren M; Wai, Eugene K; Bishop, Paul; Kwon, Brian K; Dagenais, Simon

2010-06-01

Low back pain (LBP) is a prevalent and expensive musculoskeletal condition that predominantly occurs in working-age individuals of industrialized nations. Although numerous occupational physical activities have been implicated in its etiology, determining the causation of occupational LBP still remains a challenge. To conduct a systematic review evaluating the causal relationship between occupational pushing or pulling and LBP. Systematic review of the literature. Studies reporting an association between occupational pushing or pulling and LBP. Numerical association between exposure to pushing or pulling and the presence of LBP. A systematic review was performed to identify, evaluate, and summarize the literature related to establishing a causal relationship, according to Bradford-Hill criteria for causation for occupational pushing or pulling and LBP. A search was conducted using Medline, EMBASE, CINAHL, Cochrane Library, and OSH-ROM, gray literature, hand-searching occupational health journals, reference lists of included studies, and expert knowledge. Methodological quality was assessed using a modified Newcastle-Ottawa Scale. This search yielded 2,766 citations. Thirteen studies met the inclusion criteria. Eight were high-quality studies and five were low-quality studies. There was conflicting evidence with one high-quality study demonstrating a positive association between occupational pushing or pulling and LBP and five studies showing no relationship. One study reported a nonstatistically significant dose-response trend, four studies discussed temporality of which one indicated a positive finding, two studies discussed the biological plausibility of a causal link between occupational pushing or pulling and LBP, and no evidence was uncovered to assess the experiment criterion. A qualitative summary of existing studies was not able to find any high-quality studies that fully satisfied any of the Bradford-Hill causation criteria for occupational pushing or

eResearch: librarians pushing technology to perform

CSIR Research Space (South Africa)

Van Deventer, Martha J

2008-11-01

Full Text Available , the Semantic Web, open data, data archiving, digital preservation, and data management, and how they relate to each other Phases of reporting, communication and publication are less distinct. When used in discussions of eResearch, a vocabulary familiar...

Effect of the type of maternal pushing during the second stage of labour on obstetric and neonatal outcome: a multicentre randomised trial-the EOLE study protocol.

Science.gov (United States)

Barasinski, Chloé; Vendittelli, Françoise

2016-12-20

The scientific data currently available do not allow any definitive conclusion to be reached about what type of pushing should be recommended to women during the second stage of labour. The objective of this trial is to assess and compare the effectiveness of directed open-glottis pushing versus directed closed-glottis pushing. Secondary objectives are to assess, according to the type of pushing: immediate maternal and neonatal morbidity, intermediate-term maternal pelvic floor morbidity, uncomplicated birth, and women's satisfaction at 4 weeks post partum. This multicentre randomised clinical trial compares directed closed-glottis pushing (Valsalva) versus directed open-glottis pushing during the second stage of labour in 4 hospitals of France. The study population includes pregnant women who received instruction in both types of pushing, have no previous caesarean delivery, are at term and have a vaginal delivery planned. Randomisation takes place during labour once cervical dilation ≥7 cm. The principal end point is assessed by a composite criterion: spontaneous delivery without perineal lesion (no episiotomy or spontaneous second-degree, third-degree or fourth-degree lacerations). We will need to recruit 125 women per group. The primary analysis will be by intention-to-treat analysis, with the principal results reported as crude relative risks (RRs) with their 95% CIs. A multivariate analysis will be performed to take prognostic and confounding factors into account to obtain adjusted RRs. This study was approved by a French Institutional Review Board (Comité de Protection des Personnes Sud Est 6:N°AU1168). Results will be reported in peer-reviewed journals and at scientific meetings. This study will make it possible to assess the effectiveness of 2 types of directed pushing used in French practice and to assess their potential maternal, fetal and neonatal effects. Findings from the study will be useful for counselling pregnant women before and during

Durations of second stage of labor and pushing, and adverse neonatal outcomes: a population-based cohort study.

Science.gov (United States)

Sandström, A; Altman, M; Cnattingius, S; Johansson, S; Ahlberg, M; Stephansson, O

2017-03-01

The associations between duration of second stage of labor, pushing time and risk of adverse neonatal outcomes are not fully established. Therefore, we aimed to examine such relationships. A population-based cohort study including 42 539 nulliparous women with singleton infants born in cephalic presentation at ⩾37 gestational weeks, using the Stockholm-Gotland Obstetric Cohort, Sweden, and the Swedish Neonatal Quality Register, 2008 to 2013. Poisson regression was used to analyze estimated adjusted relative risks (RRs), with 95% confidence intervals (CIs). Outcome measures were umbilical artery acidosis (pH pushing pushing ⩾60 min increased rates of acidosis from 0.57 to 1.69% (adjusted RR 2.55 (95% CI 1.51 to 4.30)). Prolonged durations of second stage of labor and pushing are associated with increased RRs of adverse neonatal outcomes. Clinical assessment of fetal well-being is essential when durations of second stage and pushing increases.

Research on Corporal Punishment Effectiveness: Contributions and Limitations.

Science.gov (United States)

Hapkiewicz, Walter G.

A review of research literature on corporal punishment reveals that the incidence of corporal punishment has increased over the last twenty years and that it is widely used in some local school districts. Because it is limited by ethical problems, research cannot answer many questions about the direct and indirect effects of corporal punishment.…

Determinants and magnitudes of manual force strengths and joint moments during two-handed standing maximal horizontal pushing and pulling.

Science.gov (United States)

Chow, Amy Y; Dickerson, Clark R

2016-04-01

Pushing and pulling are common occupational exertions that are increasingly associated with musculoskeletal complaints. This study focuses on the sensitivity of shoulder capacity to gender, handle height, exertion type (push or pull) and handle orientation for these tasks. All factors except for handle orientation influenced unilateral and total manual force strength (p pushing and pulling tasks for a diverse population. Practitioner Summary: pushing and pulling comprise nearly half of all manual materials handling tasks. Practitioners often assess, design or modify these tasks while incorporating constraints, including manual force direction and handle interface. This study provides guidance to aid design of pushing and pulling tasks in the context of shoulder physical capacity.

The effect of second-stage pushing and body mass index on postdural puncture headache.

Science.gov (United States)

Franz, Amber M; Jia, Shawn Y; Bahnson, Henry T; Goel, Akash; Habib, Ashraf S

2017-02-01

To explore how pushing during labor and body mass index affect the development of postdural puncture headache in parturients who experienced dural puncture with Tuohy needles. Retrospective cohort. Obstetric ward and operating rooms at a university-affiliated hospital. One hundred ninety parturients who had witnessed dural puncture with 17 or 18 gauge Tuohy needles from 1999-2014. Patients were categorized by pushing status and body mass index (kg/m 2 ): nonobese push, women who pushed during labor had increased risk of postdural puncture headache (odds ratio [OR], 2.1 [1.1-4.0]; P=.02), more days of headache (P=.02), and increased epidural blood patch placement (P=.02). Super obese patients were less likely to develop headache compared with nonobese (OR, 0.33 [0.13-0.85]; P=.02), obese (OR, 0.37 [0.14-0.98]; P=.045], and morbidly obese patients (OR, 0.20 [0.05-0.68]; Ppushing (OR, 0.57 [0.29-1.10]; P=.096) and super obesity (OR, 0.41 [0.16-1.02]; P=.056] were no longer significantly associated with reduced risk of postdural puncture headache. Parturients who did not push before delivery and parturients with body mass index ≥50kg/m 2 were less likely to develop postdural puncture headache in a univariate analysis. Similar trends were demonstrated in a multivariate model, but were no longer statistically significant. Copyright © 2016 Elsevier Inc. All rights reserved.

Youth researching youth: benefits, limitations and ethical considerations within a participatory research process

Directory of Open Access Journals (Sweden)

Cynthia G. Jardine

2012-05-01

Full Text Available Objectives. To examine the benefits, limitations and ethical issues associated with conducting participatory research on tobacco use using youth to research other youth. Study design. Community-based participatory research. Methods. Research on tobacco use was conducted with students in the K’àlemì Dene School and Kaw Tay Whee School in the Northwest Territories, Canada, using PhotoVoice. The Grade 9–12 students acted as researchers. Researcher reflections and observations were assessed using “member checking,” whereby students, teachers and community partners could agree or disagree with the researcher's interpretation. The students and teachers were further asked informally to share their own reflections and observations on this process. Results and conclusions. Using youth to research other youth within a participatory research framework had many benefits for the quality of the research, the youth researchers and the community. The research was perceived by the researchers and participants to be more valid and credible. The approach was more appropriate for the students, and the youth researchers gained valuable research experience and a sense of ownership of both the research process and results. Viewing smoking through their children's eyes was seen by the community to be a powerful and effective means of creating awareness of the community environment. Limitations of the approach were residual response bias of participants, the short period of time to conduct the research and failure to fully explore student motivations to smoke or not to smoke. Ethical considerations included conducting research with minors, difficulties in obtaining written parental consent, decisions on cameras (disposable versus digital and representation of all participants in the final research product.

The effects of klapskate hinge position on push-off performance: a simulation study.

Science.gov (United States)

Houdijk, Han; Bobbert, Maarten F; De Koning, Jos J; De Groot, Gert

2003-12-01

The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed skating. For this purpose, a model of the musculoskeletal system was designed to simulate a simplified, two-dimensional skating push off. To capture the essence of a skating push off, this model performed a one-leg vertical jump, from a frictionless surface, while keeping its trunk horizontally. In this model, klapskate hinge position was varied by varying the length of the foot segment between 115 and 300 mm. With each foot length, an optimal control solution was found that resulted in the maximal amount of vertical kinetic and potential energy of the body's center of mass at take off (Weff). Foot length was shown to considerably affect push-off performance. Maximal Weff was obtained with a foot length of 185 mm and decreased by approximately 25% at either foot length of 115 mm and 300 mm. The reason for this decrease was that foot length affected the onset and control of foot rotation. This resulted in a distortion of the pattern of leg segment rotations and affected muscle work (Wmus) and the efficacy ratio (Weff/Wmus) of the entire leg system. Despite its simplicity, the model very well described and explained the effects of klapskate hinge position on push off performance that have been observed in speed-skating experiments. The simplicity of the model, however, does not allow quantitative analyses of optimal klapskate hinge position for speed-skating practice.

Promise and Limitations of Big Data Research in Plastic Surgery.

Science.gov (United States)

Zhu, Victor Zhang; Tuggle, Charles Thompson; Au, Alexander Francis

2016-04-01

The use of "Big Data" in plastic surgery outcomes research has increased dramatically in the last 5 years. This article addresses some of the benefits and limitations of such research. This is a narrative review of large database studies in plastic surgery. There are several benefits to database research as compared with traditional forms of research, such as randomized controlled studies and cohort studies. These include the ease in patient recruitment, reduction in selection bias, and increased generalizability. As such, the types of outcomes research that are particularly suited for database studies include determination of geographic variations in practice, volume outcome analysis, evaluation of how sociodemographic factors affect access to health care, and trend analyses over time. The limitations of database research include data which are limited only to what was captured in the database, high power which can cause clinically insignificant differences to achieve statistical significance, and fishing which can lead to increased type I errors. The National Surgical Quality Improvement Project is an important general surgery database that may be useful for plastic surgeons because it is validated and has a large number of patients after over a decade of collecting data. The Tracking Operations and Outcomes for Plastic Surgeons Program is a newer database specific to plastic surgery. Databases are a powerful tool for plastic surgery outcomes research. It is critically important to understand their benefits and limitations when designing research projects or interpreting studies whose data have been drawn from them. For plastic surgeons, National Surgical Quality Improvement Project has a greater number of publications, but Tracking Operations and Outcomes for Plastic Surgeons Program is the most applicable database for plastic surgery research.

Determination of extra-push energies for fusion from differential fission cross-section measurements

International Nuclear Information System (INIS)

Ramamurthy, V.S.; Kapoor, S.S.

1993-01-01

Apparent discrepancies between values of extra-push energies for fusion of two heavy nuclei derived through measurements of fusion evaporation residue cross sections and of differential fission cross sections have been reported by Keller et al. We show here that with the inclusion of the recently proposed preequilibrium fission decay channel in the analysis, there is no inconsistency between the two sets of data in terms of the deduced extra-push energies

Thermal modeling of core sampling in flammable gas waste tanks. Part 1: Push-mode sampling

International Nuclear Information System (INIS)

Unal, C.; Stroh, K.; Pasamehmetoglu, K.O.

1997-01-01

The radioactive waste stored in underground storage tanks at Hanford site is routinely being sampled for waste characterization purposes. The push- and rotary-mode core sampling is one of the sampling methods employed. The waste includes mixtures of sodium nitrate and sodium nitrite with organic compounds that can produce violent exothermic reactions if heated above 160 C during core sampling. A self-propagating waste reaction would produce very high temperatures that eventually result in failure of the tank and radioactive material releases to environment. A two-dimensional thermal model based on a lumped finite volume analysis method is developed. The enthalpy of each node is calculated from the first law of thermodynamics. A flash temperature and effective contact area concept were introduced to account the interface temperature rise. No maximum temperature rise exceeding the critical value of 60 C was found in the cases studied for normal operating conditions. Several accident conditions are also examined. In these cases it was found that the maximum drill bit temperature remained below the critical reaction temperature as long as a 30 scfm purge flow is provided the push-mode drill bit during sampling in rotary mode. The failure to provide purge flow resulted in exceeding the limiting temperatures in a relatively short time

Newly Identified Gait Patterns in Patients With Multiple Sclerosis May Be Related to Push-off Quality.

Science.gov (United States)

Kempen, Jiska C E; Doorenbosch, Caroline A M; Knol, Dirk L; de Groot, Vincent; Beckerman, Heleen

2016-11-01

Limited walking ability is an important problem for patients with multiple sclerosis. A better understanding of how gait impairments lead to limited walking ability may help to develop more targeted interventions. Although gait classifications are available in cerebral palsy and stroke, relevant knowledge in MS is scarce. The aims of this study were: (1) to identify distinctive gait patterns in patients with MS based on a combined evaluation of kinematics, gait features, and muscle activity during walking and (2) to determine the clinical relevance of these gait patterns. This was a cross-sectional study of 81 patients with MS of mild-to-moderate severity (Expanded Disability Status Scale [EDSS] median score=3.0, range=1.0-7.0) and an age range of 28 to 69 years. The patients participated in 2-dimensional video gait analysis, with concurrent measurement of surface electromyography and ground reaction forces. A score chart of 73 gait items was used to rate each gait analysis. A single rater performed the scoring. Latent class analysis was used to identify gait classes. Analysis of the 73 gait variables revealed that 9 variables could distinguish 3 clinically meaningful gait classes. The 9 variables were: (1) heel-rise in terminal stance, (2) push-off, (3) clearance in initial swing, (4) plantar-flexion position in mid-swing, (5) pelvic rotation, (6) arm-trunk movement, (7) activity of the gastrocnemius muscle in pre-swing, (8) M-wave, and (9) propulsive force. The EDSS score and gait speed worsened in ascending classes. Most participants had mild-to-moderate limitations in walking ability based on their EDSS scores, and the number of walkers who were severely limited was small. Based on a small set of 9 variables measured with 2-dimensional clinical gait analysis, patients with MS could be divided into 3 different gait classes. The gait variables are suggestive of insufficient ankle push-off. © 2016 American Physical Therapy Association.

CERN's surveyors are pushing back the frontiers of precision

CERN Multimedia

2001-01-01

Aiming at a target on the other side of the Alps, 730 kilometres from CERN, or controlling the positions of thousands of devices to a precision of one tenth of a millimetre, these are just some of the painstaking tasks undertaken by the surveyors in the Positioning Metrology and Surveying Group. These masters of measurement are pushing precision to its very limit.Go down into the LEP tunnel, walk about half a mile and then try to imagine how you could possibly take precise aim at something hundreds of kilometres away without any reference to the surface. Absurd, you might think? Not entirely, for that, in a nutshell, is the geodetic challenge of the Gran Sasso project. Indeed it is just one of the challenges faced by the surveyors in CERN's Positioning Metrology and Surveying Group, whose task it will be to aim a neutrino beam at a detector located in an underground cavern 732 kilometres away at INFN's Gran Sasso laboratory in Italy. The tools for solving such problems are provided by geodetics, the branch of...

Catheter Entrapment During Posterior Mitral Leaflet Pushing Maneuver for MitraClip Implantation.

Science.gov (United States)

Castrodeza, Javier; Amat-Santos, Ignacio J; Tobar, Javier; Varela-Falcón, Luis H

2016-06-01

MitraClip (Abbott Vascular) therapy has been reported to be an effective procedure for mitral regurgitation, especially in high-risk patients. Recently, the novel pushing maneuver technique has been described for approaching restricted and short posterior leaflets with a pigtail catheter in order to facilitate grasping of the clip. However, complications or unexpected situations may occur. We report the case of an 84-year-old patient who underwent MitraClip implantation wherein the pushing maneuver was complicated by the clip accidentally gripping the pigtail catheter along with the two leaflets.

Explanatory Definitions of the Technology Push Success Factors

Directory of Open Access Journals (Sweden)

Jari Matti Sarja

2015-04-01

Full Text Available The main task for most development-intensive organizations is to create, develop and commercialize new products and services. Because development processes are risky and failure rates are high, especially in the case of technology pushed projects, unambiguous success factors are valuable knowledge for the management of development-intensive firms. New product development and innovation literature has presented many success factors for developed products, but, unfortunately, many of them are nebulous in nature. The aim of this paper is to clarify what elements comprise the exact factors. After an extensive review and screening of the technology push success factor related literature, a total of 13 success factors were rationalized and transcribed according the previous literature. As a result, three separate keynotes were recognized, and the survey instrument framework was proposed. The practical relevance of this study is to help firm management to recognize the real actions needed to reduce product development risks and also to help scholars to focus on key issues when studying the key factors of breakthrough development cases.

Push-Pull Effects of Three Plant Secondary Metabolites on Oviposition of the Potato Tuber Moth, Phthorimaea operculella

Science.gov (United States)

Ma, Y.F.; Xiao, C.

2013-01-01

The push-pull effects of three plant secondary metabolites, azadirachtin, eucalyptol, and heptanal, on the oviposition choices of potato tubers by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) were tested in the laboratory. Azadirachtin at concentrations from 1.5 to 12 mg/L had a significant repellent effect on oviposition. Eucalyptol at concentrations from 3 to 12 mg/L promoted oviposition. Heptanal promoted oviposition at low concentrations from 0.1875 to 3.0 mg/L but repelled it at higher concentrations from 12 to 24 mg/L. The combination of azadirachtin (12 mg/L) with eucalyptol (3.0 mg/L) resulted in a significant pushpull effect of 56.3% on oviposition. The average maximum push-pull effects occurred with the combinations of azadirachtin with heptanal (12 and 0.375 mg/L, respectively; 38.7% push-pull effect), heptanal with eucalyptol (12 and 6 mg/L, respectively; 31.4% push-pull effect), and heptanal (high concentration) with heptanal (low concentration) (12.0 and 0.375 mg/L, respectively; 25% push-pull effect). PMID:24786822

Push-Pull and Feedback Mechanisms Can Align Signaling System Outputs with Inputs.

Science.gov (United States)

Andrews, Steven S; Peria, William J; Yu, Richard C; Colman-Lerner, Alejandro; Brent, Roger

2016-11-23

Many cell signaling systems, including the yeast pheromone response system, exhibit "dose-response alignment" (DoRA), in which output of one or more downstream steps closely matches the fraction of occupied receptors. DoRA can improve the fidelity of transmitted dose information. Here, we searched systematically for biochemical network topologies that produced DoRA. Most networks, including many containing feedback and feedforward loops, could not produce DoRA. However, networks including "push-pull" mechanisms, in which the active form of a signaling species stimulates downstream activity and the nominally inactive form reduces downstream activity, enabled perfect DoRA. Networks containing feedbacks enabled DoRA, but only if they also compared feedback to input and adjusted output to match. Our results establish push-pull as a non-feedback mechanism to align output with variable input and maximize information transfer in signaling systems. They also suggest genetic approaches to determine whether particular signaling systems use feedback or push-pull control. Copyright © 2016 Elsevier Inc. All rights reserved.

Research on Precision Tracking on Fast Steering Mirror and Control Strategy

Science.gov (United States)

Di, Lin; Yi-ming, Wu; Fan, Zhu

2018-01-01

Fast steering mirror is a device used for controlling the beam direction precisely. Due to the short travel of the push-pull FSM, a compound fast steering mirror system driven by both limited-angle voice coil motor and push-pull FSM together is proposed. In the compound FSM system, limited-angle voice coil motor quickly swings at wide angle, while the push-pull FSM do high frequency movement in a small range, which provides the system with the high bandwidth and long travel. In the control strategy, the method of combining feed-forward control in Kalman filtering with auto-disturbance rejection control is used to improve trajectory tracking accuracy. The simulation result shows that tracking accuracy measured by the compound method can be improved by more than 5 times than that of the conventional PID.

Assessment of physiological performance and perception of pushing different wheelchairs on indoor modular units simulating a surface roughness often encountered in under-resourced settings.

Science.gov (United States)

Sasaki, Kotaro; Rispin, Karen

2017-01-01

In under-resourced settings where motorized wheelchairs are rarely available, manual wheelchair users with limited upper-body strength and functionalities need to rely on assisting pushers for their mobility. Because traveling surfaces in under-resourced settings are often unpaved and rough, wheelchair pushers could experience high physiological loading. In order to evaluate pushers' physiological loading and to improve wheelchair designs, we built indoor modular units that simulate rough surface conditions, and tested a hypothesis that pushing different wheelchairs would result in different physiological performances and pushers' perception of difficulty on the simulated rough surface. Eighteen healthy subjects pushed two different types of pediatric wheelchairs (Moti-Go manufactured by Motivation, and KidChair by Hope Haven) fitted with a 50-kg dummy on the rough and smooth surfaces at self-selected speeds. Oxygen uptake, traveling distance for 6 minutes, and the rating of difficulty were obtained. The results supported our hypothesis, showing that pushing Moti-Go on the rough surface was physiologically less loading than KidChair, but on the smooth surface, the two wheelchairs did not differ significantly. These results indicate wheelchair designs to improve pushers' performance in under-resourced settings should be evaluated on rough surfaces.

Study on pollution control in residential kitchen based on the push-pull ventilation system

DEFF Research Database (Denmark)

Zhou, Bin; Chen, Feng; Dong, Zhibo

2016-01-01

Highlights •The push-pull ventilation system is proposed to improve IAQ inside kitchen, where air is supplied through slot air curtain and then exhausted through range hood. •CO2 reduction efficiency with application of air curtain in experiment and simulation in breathing zone was 23.7% and 23.......1%, respectively. •By orthogonal method, the influence of factors on pollution control of the push-pull ventilation system was presented....

M/G/1/K system with push-out scheme under vacation policy

Directory of Open Access Journals (Sweden)

Shoji Kasahara

1996-01-01

Full Text Available We consider an M/G/1/K system with push-out scheme and multiple vacations. This model is particularly important in situations where it is essential to provide short waiting times to messages which are selected for service. We analyze the behavior of two types of messages: one that succeeds in transmission and the other that fails. We derive the Laplace-Stieltjes transform of the waiting time distribution for the message which is eventually served. Finally, we show some numerical results including the comparisons between the push-out and the ordinary blocking models.

Correcting errors in a quantum gate with pushed ions via optimal control

DEFF Research Database (Denmark)

Poulsen, Uffe Vestergaard; Sklarz, Shlomo; Tannor, David

2010-01-01

We analyze in detail the so-called pushing gate for trapped ions, introducing a time-dependent harmonic approximation for the external motion. We show how to extract the average fidelity for the gate from the resulting semiclassical simulations. We characterize and quantify precisely all types...... of errors coming from the quantum dynamics and reveal that slight nonlinearities in the ion-pushing force can have a dramatic effect on the adiabaticity of gate operation. By means of quantum optimal control techniques, we show how to suppress each of the resulting gate errors in order to reach a high...

Push-off tests and strength evaluation of joints combining shrink fitting with bonding

Science.gov (United States)

Yoneno, Masahiro; Sawa, Toshiyuki; Shimotakahara, Ken; Motegi, Yoichi

1997-03-01

Shrink fitted joints have been used in mechanical structures. Recently, joints combining shrink fitting with anaerobic adhesives bonded between the shrink fitted surfaces have been appeared in order to increase the joint strength. In this paper, push-off test was carried out on strength of joints combining shrink fitting with bonding by material testing machine. In addition, the push-off strength of shrink fitting joints without an anaerobic adhesive was also measured. In the experiments, the effects of the shrinking allowance and the outer diameter of the rings on the joint strength are examined. The interface stress distribution in bonded shrink fitted joints subjected to a push-off load is analyzed using axisymmetrical theory of elasticity as a four-body contact problem. Using the interface stress distribution, a method for estimating joint strength is proposed. The experimental results are in a fairly good agreement with the numerical results. It is found that the strength of combination joints is greater than that of shrink fitted joints.

The strategic ''pull'' and operational ''push'' of total quality management in UK regional electricity service companies

Energy Technology Data Exchange (ETDEWEB)

McAdam, R.; McLean, J.; Henderson, J.

2003-04-30

The aim of this paper is to evaluate whether the UK regional electricity companies (RECs) has used total quality management (TQM) as a ''push'' or as a ''pull'' change methodology. ''Push'' is the operational improvement role of TQM; ''pull'' is the strategic or direction giving, improvement role of TQM. Following the onset of privatisation in 1990 there has been evidence of the RECs adopting TQM in both ''push'' and ''pull'' methodologies with varying degrees of success. An evaluation of the change processes involved will enable improved change models to be developed leading to increased business effectiveness in this 30 billion pounds sterling industry. Other possible benefits include the possible generalisations to other utilities such as water, roads, gas and telecoms. The research methodology includes a comparative case study analysis of five RECs, which have used TQM as their overarching approach to change. One of the cases is analysed to a more in-depth level based on the multiple case findings. The findings indicate that the ''push-pull'' analysis enables the full range of TQM activities to be evaluated in the RECs studied. Overall, there is a need to have a balanced portfolio of operational or ''push''-based TQM activity that is driven by strategic or ''pull'' based TQM planning and activity. (author)

Instructions to "push as hard as you can" improve average chest compression depth in dispatcher-assisted cardiopulmonary resuscitation.

Science.gov (United States)

Mirza, Muzna; Brown, Todd B; Saini, Devashish; Pepper, Tracy L; Nandigam, Hari Krishna; Kaza, Niroop; Cofield, Stacey S

2008-10-01

Cardiopulmonary resuscitation (CPR) with adequate chest compression depth appears to improve first shock success in cardiac arrest. We evaluate the effect of simplification of chest compression instructions on compression depth in dispatcher-assisted CPR protocol. Data from two randomized, double-blinded, controlled trials with identical methodology were combined to obtain 332 records for this analysis. Subjects were randomized to either modified Medical Priority Dispatch System (MPDS) v11.2 protocol or a new simplified protocol. The main difference between the protocols was the instruction to "push as hard as you can" in the simplified protocol, compared to "push down firmly 2in. (5cm)" in MPDS. Data were recorded via a Laerdal ResusciAnne SkillReporter manikin. Primary outcome measures included: chest compression depth, proportion of compressions without error, with adequate depth and with total release. Instructions to "push as hard as you can", compared to "push down firmly 2in. (5cm)", resulted in improved chest compression depth (36.4 mm vs. 29.7 mm, pCPR instructions by changing "push down firmly 2in. (5cm)" to "push as hard as you can" achieved improvement in chest compression depth at no cost to total release or average chest compression rate.

Dielectric films for solar and laser-pushed lightsails

International Nuclear Information System (INIS)

Landis, Geoffrey A.

2000-01-01

This project analyzed the potential use of dielectric thin films for solar and laser sails. Such light-pushed sails allow the possibility of fuel-free propulsion in space. This makes possible missions of extremely high delta-V, potentially as high as 30,000 km/sec (0.1c), which is required for a fly-by mission to a nearby star

'Pushing the boundaries of interpretation': The link between the ...

African Journals Online (AJOL)

'Pushing the boundaries of interpretation': The link between the nature and purpose of missionary records and the underutilisation of the Roman Catholic missionary ... The article uses the author's experience with Roman Catholic missionary archives in South-western as a window through which to project into the general ...

Increasing ankle push-off work with a powered prosthesis does not necessarily reduce metabolic rate for transtibial amputees.

Science.gov (United States)

Quesada, Roberto E; Caputo, Joshua M; Collins, Steven H

2016-10-03

Amputees using passive ankle-foot prostheses tend to expend more metabolic energy during walking than non-amputees, and reducing this cost has been a central motivation for the development of active ankle-foot prostheses. Increased push-off work at the end of stance has been proposed as a way to reduce metabolic energy use, but the effects of push-off work have not been tested in isolation. In this experiment, participants with unilateral transtibial amputation (N=6) walked on a treadmill at a constant speed while wearing a powered prosthesis emulator. The prosthesis delivered different levels of ankle push-off work across conditions, ranging from the value for passive prostheses to double the value for non-amputee walking, while all other prosthesis mechanics were held constant. Participants completed six acclimation sessions prior to a data collection in which metabolic rate, kinematics, kinetics, muscle activity and user satisfaction were recorded. Metabolic rate was not affected by net prosthesis work rate (p=0.5; R 2 =0.007). Metabolic rate, gait mechanics and muscle activity varied widely across participants, but no participant had lower metabolic rate with higher levels of push-off work. User satisfaction was affected by push-off work (p=0.002), with participants preferring values of ankle push-off slightly higher than in non-amputee walking, possibly indicating other benefits. Restoring or augmenting ankle push-off work is not sufficient to improve energy economy for lower-limb amputees. Additional necessary conditions might include alternate timing or control, individualized tuning, or particular subject characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cohesive Zone Model Based Numerical Analysis of Steel-Concrete Composite Structure Push-Out Tests

Directory of Open Access Journals (Sweden)

J. P. Lin

2014-01-01

Full Text Available Push-out tests were widely used to determine the shear bearing capacity and shear stiffness of shear connectors in steel-concrete composite structures. The finite element method was one efficient alternative to push-out testing. This paper focused on a simulation analysis of the interface between concrete slabs and steel girder flanges as well as the interface of the shear connectors and the surrounding concrete. A cohesive zone model was used to simulate the tangential sliding and normal separation of the interfaces. Then, a zero-thickness cohesive element was implemented via the user-defined element subroutine UEL in the software ABAQUS, and a multiple broken line mode was used to define the constitutive relations of the cohesive zone. A three-dimensional numerical analysis model was established for push-out testing to analyze the load-displacement curves of the push-out test process, interface relative displacement, and interface stress distribution. This method was found to accurately calculate the shear capacity and shear stiffness of shear connectors. The numerical results showed that the multiple broken lines mode cohesive zone model could describe the nonlinear mechanical behavior of the interface between steel and concrete and that a discontinuous deformation numerical simulation could be implemented.

Three-dimensional kinematics of the knee and ankle joints for three consecutive push-offs during ice hockey skating starts.

Science.gov (United States)

Lafontaine, Dany

2007-09-01

Little biomechanical research has been conducted recently on hockey skating despite the sport's worldwide appeal. One reason for this lack of biomechanical knowledge stems from the difficulty of collecting data. The lack of accuracy, the disputable realism of treadmills, and the large field of view required are some of the technical challenges that have to be overcome. The main objective of the current study was to improve our knowledge of the joint kinematics during the skating stroke. A second objective was to improve the data collection system we developed and the third was to establish if a kinematic progression exists in the hockey skating stroke similar to that in speed skating. Relative motions at the knee and ankle joints were computed using a joint coordinate system approach. The differences at the knee joints in push-offs indicated that the skating skill was progressively changing with each push-off. The relative stability of the ankle angles can be attributed to the design of the skate boots, which have recently become very rigid. Further research on ice hockey skating is warranted and should include more skaters and investigate the effect various starting strategies and variations in equipment have on skaters' performance.

Early pushing urge in labour and midwifery practice: a prospective observational study at an Italian maternity hospital.

Science.gov (United States)

Borrelli, Sara E; Locatelli, Anna; Nespoli, Antonella

2013-08-01

to investigate the early pushing urge (EPU) incidence in one maternity unit and explore how it is managed by midwives. The relation to some obstetric outcomes was also observed but not analysed in depth. prospective observational study. Italian maternity hospital. 60 women (44 nullips and 16 multips) experiencing EPU during labour. the total EPU incidence percentage was 7.6%. The single midwives' incidences range had a very wide margin, noting an inverse proportion between the number of diagnoses of EPU and midwife's waiting time between urge to push and vaginal examination. Two care policies were adopted in relation to the phenomenon: the stop pushing technique (n=52/60) and the 'let the woman do what she feels' technique (n=8/60). In case of stop pushing techniques, midwives proposed several combined techniques (change of maternal position, blowing breath, vocalisation, use of the bath). The EPU diagnosis at less than 8cm of cervical dilatation was associated with more medical interventions. Maternal and neonatal outcomes were within the range of normal physiology. An association between the dilatation at EPU diagnosis and obstetric outcomes was observed, in particular the modality of childbirth and perineal outcomes. this paper contributes new knowledge to the body of literature around the EPU phenomenon during labour and midwifery practices adopted in response to it. Overall, it could be argued that EPU is a physiologic variation in labour if maternal and fetal conditions are good. Midwives might suggest techniques to woman to help her to stay with the pain, such as change of position, blowing breath, vocalisation and use of the bath. However, the impact of policies, guidelines and culture on midwifery practices of the specific setting are a limitation of the study because it is not representative of other similar maternity units. Thus, a larger scale work should be considered, including different units and settings. The optimal response to the phenomenon

Push-Broom-Type Very High-Resolution Satellite Sensor Data Correction Using Combined Wavelet-Fourier and Multiscale Non-Local Means Filtering

Science.gov (United States)

Kang, Wonseok; Yu, Soohwan; Seo, Doochun; Jeong, Jaeheon; Paik, Joonki

2015-01-01

In very high-resolution (VHR) push-broom-type satellite sensor data, both destriping and denoising methods have become chronic problems and attracted major research advances in the remote sensing fields. Since the estimation of the original image from a noisy input is an ill-posed problem, a simple noise removal algorithm cannot preserve the radiometric integrity of satellite data. To solve these problems, we present a novel method to correct VHR data acquired by a push-broom-type sensor by combining wavelet-Fourier and multiscale non-local means (NLM) filters. After the wavelet-Fourier filter separates the stripe noise from the mixed noise in the wavelet low- and selected high-frequency sub-bands, random noise is removed using the multiscale NLM filter in both low- and high-frequency sub-bands without loss of image detail. The performance of the proposed method is compared to various existing methods on a set of push-broom-type sensor data acquired by Korean Multi-Purpose Satellite 3 (KOMPSAT-3) with severe stripe and random noise, and the results of the proposed method show significantly improved enhancement results over existing state-of-the-art methods in terms of both qualitative and quantitative assessments. PMID:26378532

Spaceborne L-band Radiometers: Push-broom or Synthetic Aperture?

DEFF Research Database (Denmark)

Skou, Niels

2004-01-01

L-band radiometers can measure ocean salinity and soil moisture from space. A synthetic aperture radiometer system, SMOS, is under development by ESA for launch in 2007. A real aperture push-broom system, Aquarius, has been approved by NASA for launch in 2008. Pros et cons of the two fundamentally...

Investigation of the extra-extra-push by pre-scission neutron measurements with DEMON

International Nuclear Information System (INIS)

Rudolf, Gerard

1998-01-01

The objective of this talk is to present a simple method to calculate pre- and post-scission neutron multiplicities in the frame of the Bass model. This method is of particular interest for very heavy systems for which an extra-extra-push is supposed to hinder fusion. The multiplicities calculated by the model are compared to published data covering a broad range of projectile and target masses, and to more recent ones obtained with the help of the Demon detector and addressing specifically the existence of the extra-extra-push

Correcting errors in a quantum gate with pushed ions via optimal control

International Nuclear Information System (INIS)

Poulsen, Uffe V.; Sklarz, Shlomo; Tannor, David; Calarco, Tommaso

2010-01-01

We analyze in detail the so-called pushing gate for trapped ions, introducing a time-dependent harmonic approximation for the external motion. We show how to extract the average fidelity for the gate from the resulting semiclassical simulations. We characterize and quantify precisely all types of errors coming from the quantum dynamics and reveal that slight nonlinearities in the ion-pushing force can have a dramatic effect on the adiabaticity of gate operation. By means of quantum optimal control techniques, we show how to suppress each of the resulting gate errors in order to reach a high fidelity compatible with scalable fault-tolerant quantum computing.

NASA Green Propulsion Technologies Pushing Aviation to New Heights

Science.gov (United States)

Free, James M.; Jennings, Francis T.; Adanich, Emery; Del Rosario, Ruben; Felder, James L.

2014-01-01

Center Director Free is providing the Keynote at the Disruptive Propulsion Conference, sponsored by Cranfield University, Cranfield, Bedfordshire, England in November. Director Free will be presenting a PowerPoint presentation titled, NASA Green Propulsion Technologies Pushing Aviation to New Heights at both the conference and a meeting at the Royal Aeronautical Society.

Limited irrigation research and infrared thermometry for detecting water stress

Science.gov (United States)

The USDA-ARS Limited Irrigation Research Farm, located outside of Greeley Colorado, is an experiment evaluating management perspectives of limited irrigation water. An overview of the farm systems is shown, including drip irrigation systems, water budgeting, and experimental design, as well as preli...

THE EFFECTS OF DIFFERENT TRUNK INCLINATIONS ON BILATERAL TRUNK MUSCULAR ACTIVITIES, CENTRE OF PRESSURE AND FORCE EXERTIONS IN STATIC PUSHING POSTURES.

Science.gov (United States)

Sanjaya, Kadek Heri; Lee, Soomin; Sriwarno, Andar Bagus; Shimomura, Yoshihito; Katsuura, Tetsuo

2014-06-01

In order to reconcile contradictory results from previous studies on manual pushing, a study was conducted to examine the effect of trunk inclination on muscular activities, centre of pressure (COP) and force exertion during static pushing. Ten subjects pushed at 0 degrees, 15 degrees, 30 degrees, and 45 degrees body inclinations in parallel and staggered feet stances. Wall and ground force plates measured pushing force, wall COP, vertical ground reaction force (GRF) and ground COP. Electromyogram data were recorded at 10 trunk muscle sites. Pushing force was found to increase with body inclination. GRF peaked at 15 degrees and reached its lowest level at the 45 degrees inclination. The lowest wall force plate standard deviation of COP displacement was found at the 30 degrees inclination. The lowest low back muscular activity was found at the 15 degrees and 30 degrees inclinations. Based on force exertion, muscular load, and stability, the 30 degrees body inclination was found to be the best posture for static pushing. This study also showed asymmetry in muscular activity and force exertion which has been received less attention in manual pushing studies. These findings will require further study.

Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

Science.gov (United States)

Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Asif, Syed Amanula Syed

2013-05-07

A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

Individual muscle contributions to push and recovery subtasks during wheelchair propulsion.

Science.gov (United States)

Rankin, Jeffery W; Richter, W Mark; Neptune, Richard R

2011-04-29

Manual wheelchair propulsion places considerable physical demand on the upper extremity and is one of the primary activities associated with the high prevalence of upper extremity overuse injuries and pain among wheelchair users. As a result, recent effort has focused on determining how various propulsion techniques influence upper extremity demand during wheelchair propulsion. However, an important prerequisite for identifying the relationships between propulsion techniques and upper extremity demand is to understand how individual muscles contribute to the mechanical energetics of wheelchair propulsion. The purpose of this study was to use a forward dynamics simulation of wheelchair propulsion to quantify how individual muscles deliver, absorb and/or transfer mechanical power during propulsion. The analysis showed that muscles contribute to either push (i.e., deliver mechanical power to the handrim) or recovery (i.e., reposition the arm) subtasks, with the shoulder flexors being the primary contributors to the push and the shoulder extensors being the primary contributors to the recovery. In addition, significant activity from the shoulder muscles was required during the transition between push and recovery, which resulted in increased co-contraction and upper extremity demand. Thus, strengthening the shoulder flexors and promoting propulsion techniques that improve transition mechanics have much potential to reduce upper extremity demand and improve rehabilitation outcomes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Older adults utilize less efficient postural control when performing pushing task.

Science.gov (United States)

Lee, Yun-Ju; Chen, Bing; Aruin, Alexander S

2015-12-01

The ability to maintain balance deteriorates with increasing age. The aim was to investigate the role of age in generation of anticipatory (APA) and compensatory (CPA) postural adjustments during pushing an object. Older (68.8 ± 1.0 years) and young adults (30.1 ± 1.4 years) participated in the experiment involving pushing an object (a pendulum attached to the ceiling) using both hands. Electrical activity of six leg and trunk muscles and displacements of the center of pressure (COP) were recorded and analyzed during the APA and CPA phases. The onset time, integrals of muscle activity, and COP displacements were determined. In addition, the indexes of co-activation and reciprocal activation of muscles for the shank, thigh, and trunk segments were calculated. Older adults, compared to young adults, showed less efficient postural control seen as delayed anticipatory muscle onset times and delayed COP displacements. Moreover, older adults used co-activation of muscles during the CPA phase while younger subjects utilized reciprocal activation of muscles. The observed diminished efficiency of postural control during both anticipatory and compensatory postural adjustments observed in older adults might predispose them to falls while performing tasks involving pushing. The outcome provides a background for future studies focused on the optimization of the daily activities of older adults. Copyright © 2015 Elsevier Ltd. All rights reserved.

Push-you-pull-you: the boundaried self in close relationships.

Science.gov (United States)

Rempel, John K; Burris, Christopher T

2006-02-01

Based on Amoebic Self Theory, the authors propose that the salience of different threats to the self affects the extent to which an intimate relationship partner is pushed away (excluded) or pulled closer (included). When social threat is salient among persons in relationships, it is hypothesized that partners will attempt to defuse the resulting sense of interpersonal vulnerability: offending partners may be pushed away, whereas offenders themselves may draw closer. When spatial-symbolic threat is salient and the relationship's capacity to function as an identity marker is jeopardized, it is hypothesized that the partner--regardless of his or her role--will be pulled closer to maintain the perception that the relationship is secure. Self-report responses to hypothetical scenarios and perceptions of behaviors during a role-play were generally consistent with these hypotheses, suggesting that both an intimate partner and the relationship with that partner can be incorporated into the self.

Achieving food security for one million sub-Saharan African poor through push-pull innovation by 2020.

Science.gov (United States)

Khan, Zeyaur R; Midega, Charles A O; Pittchar, Jimmy O; Murage, Alice W; Birkett, Michael A; Bruce, Toby J A; Pickett, John A

2014-04-05

Food insecurity is a chronic problem in Africa and is likely to worsen with climate change and population growth. It is largely due to poor yields of the cereal crops caused by factors including stemborer pests, striga weeds and degraded soils. A platform technology, 'push-pull', based on locally available companion plants, effectively addresses these constraints resulting in substantial grain yield increases. It involves intercropping cereal crops with a forage legume, desmodium, and planting Napier grass as a border crop. Desmodium repels stemborer moths (push), and attracts their natural enemies, while Napier grass attracts them (pull). Desmodium is very effective in suppressing striga weed while improving soil fertility through nitrogen fixation and improved organic matter content. Both companion plants provide high-value animal fodder, facilitating milk production and diversifying farmers' income sources. To extend these benefits to drier areas and ensure long-term sustainability of the technology in view of climate change, drought-tolerant trap and intercrop plants are being identified. Studies show that the locally commercial brachiaria cv mulato (trap crop) and greenleaf desmodium (intercrop) can tolerate long droughts. New on-farm field trials show that using these two companion crops in adapted push-pull technology provides effective control of stemborers and striga weeds, resulting in significant grain yield increases. Effective multi-level partnerships have been established with national agricultural research and extension systems, non-governmental organizations and other stakeholders to enhance dissemination of the technology with a goal of reaching one million farm households in the region by 2020. These will be supported by an efficient desmodium seed production and distribution system in eastern Africa, relevant policies and stakeholder training and capacity development.

Results of speech improvement following simultaneous push-back together with velopharyngeal flap surgery in cleft palate patients.

Science.gov (United States)

Wermker, Kai; Lünenbürger, Henning; Joos, Ulrich; Kleinheinz, Johannes; Jung, Susanne

2014-07-01

Velopharyngeal insufficiency (VPI) can be caused by a variety of disorders. The most common cause of VPI is the association with cleft palate. The aim of this study was to evaluate the effectiveness of different surgical techniques for cleft palate patients with VPI: (1) velopharyngoplasty with an inferiorly based posterior pharyngeal flap (VPP posterior, Schönborn-Rosenthal), and (2) combination of VPP posterior and push-back operation (Dorrance). 41 subjects (26 females, 15 males) with VPI were analysed. Hypernasality was judged subjectively and nasalance data were assessed objectively using the NasalView system preoperative and 6 months postoperative. Subjective analysis showed improved speech results regarding hypernasality for all OP-techniques with good results for VPP posterior and VPP posterior combined with push-back with success rates of 94.4% and 87.7%, respectively. Objective analysis showed a statistically significant reduction of nasalance for both VPP posterior and VPP posterior combined with push-back (p push-back. Based on our findings, both VPP posterior and VPP posterior combined with push-back showed good results in correction of hypernasality in cleft patients with velopharyngeal insufficiency. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Exploring tourists push and pull motivations to visit Mauritius as a tourist destination

Directory of Open Access Journals (Sweden)

Hemant Kassean

2013-01-01

Full Text Available This study examines the motivational push and pull-factors that affect tourists’ decision in their choice of a holiday destination. 200 questionnaires were completed using a face to face interview among specific groups of travellers to Mauritius (English, French, German, Italian and South African tourists at various points on the island. The findings demonstrate that rest and relaxation are the most compelling push motivation forces followed by nostalgia, escape, novelty and social interaction. The key pull based motives were found to be the special climate and weather of Mauritius, the exquisite landscape and scenery, unique flora and fauna, exotic beaches, the exotic ambience and atmosphere, the welcoming nature of Mauritian hospitality and the authentic Mauritian culture. The Push and pull factors between first time visitors and repeat visitors are discussed in this article and the study essentially contributes to our overall understanding of why holiday makers take travel decisions to opt for long- haul destinations like Mauritius, and can therefore help destination marketers develop better marketing programmes to meet the specific needs of their customers.

Effects of pushing height on trunk posture and trunk muscle activity when a cart suddenly starts or stops moving.

Science.gov (United States)

Lee, Yun-Ju; Hoozemans, Marco J M; van Dieën, Jaap H

2012-01-01

Unexpected sudden (un)loading of the trunk may induce inadequate responses of trunk muscles and uncontrolled trunk motion. These unexpected perturbations may occur in pushing tasks, when the cart suddenly starts moving (unloading) or is blocked by an obstacle (loading). In pushing, handle height affects the user's working posture, which may influence trunk muscle activity and trunk movement in response to the perturbation. Eleven healthy male subjects pushed a 200 kg cart with handles at shoulder and hip height in a start condition (sudden release of brakes) and a stop condition (bumping into an obstacle). Before the perturbation, the baseline of the trunk inclination, internal moment and trunk extensor muscle activity were significantly higher when pushing at hip height than at shoulder height. After the perturbation, the changes in trunk inclination and internal moment were significantly larger when pushing at shoulder height than at hip height in both conditions. The opposite directions of changes in trunk inclination and internal moment suggest that the unexpected perturbations caused uncontrolled trunk motion. Pushing at shoulder height may impose a high risk of low-back injury due to the low trunk stiffness and large involuntary trunk motion occurring after carts suddenly move or stop.

A Psychometric Study of Reading Processes in L2 Acquisition: Deploying Deep Processing to Push Learners' Discourse Towards Syntactic Processing-Based Constructions

Science.gov (United States)

Manuel, Carlos J.

2009-01-01

This study assesses reading processes and/or strategies needed to deploy deep processing that could push learners towards syntactic-based constructions in L2 classrooms. Research has found L2 acquisition to present varying degrees of success and/or fossilization (Bley-Vroman 1989, Birdsong 1992 and Sharwood Smith 1994). For example, learners have…

Push plate, mounting assembly, circuit board, and method of assembling thereof for ball grid array packages

Science.gov (United States)

Vaughn, Mark R.; Montague, Stephen

2017-05-16

A push plate that includes springs in the form of cantilever flexures and an inspection window is disclosed. The push plate provides a known, uniform, down force and minimal torque to a package to be tested. The cantilevers have a known, calculable down force producing stiffness. The window provides for viewing of the package during testing.

40 CFR 63.7293 - What work practice standards must I meet for fugitive pushing emissions if I have a non-recovery...

Science.gov (United States)

2010-07-01

... meet for fugitive pushing emissions if I have a non-recovery coke oven battery? 63.7293 Section 63.7293... Standards for Hazardous Air Pollutants for Coke Ovens: Pushing, Quenching, and Battery Stacks Emission... pushing emissions if I have a non-recovery coke oven battery? (a) You must meet the requirements in...

Flutter and limit cycle oscillation suppression using linear and nonlinear tuned vibration absorbers

OpenAIRE

Verstraelen, Edouard; Kerschen, Gaëtan; Dimitriadis, Grigorios

2017-01-01

Aircraft are more than ever pushed to their limits for performance reasons. Consequently, they become increasingly nonlinear and they are more prone to undergo aeroelastic limit cycle oscillations. Structural nonlinearities affect aircraft such as the F-16, which can undergo store-induced limit cycle oscillations (LCOs). Furthermore, transonic buzz can lead to LCOs because of moving shock waves in transonic flight conditions on many aircraft. This study presents a numerical investigation o...

Validity and Reliability of the PUSH Wearable Device to Measure Movement Velocity During the Back Squat Exercise.

Science.gov (United States)

Balsalobre-Fernández, Carlos; Kuzdub, Matt; Poveda-Ortiz, Pedro; Campo-Vecino, Juan Del

2016-07-01

Balsalobre-Fernández, C, Kuzdub, M, Poveda-Ortiz, P, and Campo-Vecino, Jd. Validity and reliability of the PUSH wearable device to measure movement velocity during the back squat exercise. J Strength Cond Res 30(7): 1968-1974, 2016-The purpose of this study was to analyze the validity and reliability of a wearable device to measure movement velocity during the back squat exercise. To do this, 10 recreationally active healthy men (age = 23.4 ± 5.2 years; back squat 1 repetition maximum [1RM] = 83 ± 8.2 kg) performed 3 repetitions of the back squat exercise with 5 different loads ranging from 25 to 85% 1RM on a Smith Machine. Movement velocity for each of the total 150 repetitions was simultaneously recorded using the T-Force linear transducer (LT) and the PUSH wearable band. Results showed a high correlation between the LT and the wearable device mean (r = 0.85; standard error of estimate [SEE] = 0.08 m·s) and peak velocity (r = 0.91, SEE = 0.1 m·s). Moreover, there was a very high agreement between these 2 devices for the measurement of mean (intraclass correlation coefficient [ICC] = 0.907) and peak velocity (ICC = 0.944), although a systematic bias between devices was observed (PUSH peak velocity being -0.07 ± 0.1 m·s lower, p ≤ 0.05). When measuring the 3 repetitions with each load, both devices displayed almost equal reliability (Test-retest reliability: LT [r = 0.98], PUSH [r = 0.956]; ICC: LT [ICC = 0.989], PUSH [ICC = 0.981]; coefficient of variation [CV]: LT [CV = 4.2%], PUSH [CV = 5.0%]). Finally, individual load-velocity relationships measured with both the LT (R = 0.96) and the PUSH wearable device (R = 0.94) showed similar, very high coefficients of determination. In conclusion, these results support the use of an affordable wearable device to track velocity during back squat training. Wearable devices, such as the one in this study, could have valuable practical applications for strength and conditioning coaches.

Influence of Er,Cr:YSGG Laser Surface Treatments on Micro Push-Out Bond Strength of Fiber Posts to Composite Resin Core Materials

Directory of Open Access Journals (Sweden)

Mehrsima Ghavami-Lahiji

2018-03-01

Full Text Available Statement of problem: The bonding of fiber post to resin core or root dentin is challenged by limited penetration of resin material to the polymeric matrix of fiber posts. Objectives: The purpose of this study was to investigate the effect of Er,Cr:YSGG on micro push-out bond strength of glass fiber posts to resin core material. Materials and Methods: We used 2 commercially available fiber posts, Exacto (Angelus and White Post DC (FGM, which had similar coronal diameters. Specimens of each fiber post (n=36 were randomly divided into three subgroups (n=12 posts per group according to different surface treatment methods: control (no surface treatment, irradiation by 1W Er,Cr:YSGG, and irradiation by 1.5W Er,Cr:YSGG. A cylindrical plastic tube was placed around the post. Resin core material was filled into the tube and cured. Coronal portions of the posts were sectioned into 1-mm-thick slices. Then, the specimens were subjected to a thermocyling device for 3000 cycles. The micro push-out test was carried out using a Universal Testing Machine. Data were analyzed using one-way ANOVA followed by Tukey’s HSD post hoc test to investigate the effect of different surface treatments on each type of fiber post. Results: The 1.5W Er,Cr:YSGG laser statistically reduced micro push-out bond strength values in the Exacto groups (P0.05. Mode of failure analysis showed that mixed failure was the predominant failure type for all surface treatment groups. Conclusions: The beneficial effect of Er,Cr:YSGG laser application could not be confirmed based on the results of this in vitro study. Er,Cr:YSGG laser could not significantly enhance the bond strength values. However, the 1.5W laser statistically decreased micro push-out bond strength in the Exacto fiber posts.

45-Day safety screen results for Tank 241-U-201, push mode, cores 70, 73 and 74

International Nuclear Information System (INIS)

Sathyanarayana, P.

1995-01-01

Three core samples, each having two segments, from Tank 241-U-201 (U-201) were received by the 222-S Laboratories. Safety screening analysis, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and total alpha activity were conducted on Core 70, Segment 1 and 2 and on Core 73, Segment 1 and 2. Core 74, Segment 1 and 2 were taken to test rotary bit in push mode sampling. No analysis was requested on Core 74, Segment 1 and 2. Analytical results for the TGA analyses for Core 70, Segment 1, Upper half solid sample was less than the safety screening notification limit of 17 percent water. Notification was made on April 27, 1995. No exotherm was associated with this sample. Analytical results are presented in Tables 1 to 4, with the applicable notification limits shaded

Push an pull forces in the building and construction industry

NARCIS (Netherlands)

Frings-Dresen, M. H. W.; Windhorst, Judith; Hoozemans, M. J M; Van Der Beek, Allard J.; Van der Molen, Henk F.

2000-01-01

Push and pull activities are increasing in the building and construction industry. These activities can be assumed as one of the risk factors for the development of low back and upper extremity complaints. For a risk evaluation, besides the frequency and the duration of the activities, information

Tank 241-U-105 push mode core sampling and analysis plan

International Nuclear Information System (INIS)

Bell, K.E.

1995-01-01

This Sampling and Analysis Plan (SAP) will identify characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples and two push mode core samples from tank 241-U-105 (U-105)

THE EFFECTS OF HOMOGENEOUS AND HETEROGENEOUS PUSHED OUTPUT INSTRUCTIONS ON SPEAKING COMPLEXITY

Directory of Open Access Journals (Sweden)

Parviz Ghasedi

2017-12-01

Full Text Available This study was set out to investigate the efficacy of homogeneous and heterogeneous pushed output based instruction on upper-intermediate EFL learner’ speaking complexity. To do so, 41 (17 males and 24 females EFL learners were selected from University of Zabol based on the results of OPT. Then, they were put in control and experimental groups based on the predetermined criteria. Retelling and decision making tasks were used in the treatments of experimental groups while control group received placebo during 15 sessions, twice a week. Public versions of IELTS speaking test were used as pre/post-test. The results of Independent sample t-test indicated that experimental groups outperformed control group. On the other hand, statistical analyses showed no significant differences between male and female speech complexity. To sum up, the findings demonstrated the fruitful effects of collaborative pushed output activities on speaking sub-skills. Likewise, the results suggested the implementation of similar strategies in the development of male and female speaking dimensions. Based on the findings, it can be claimed that teacher preparation programs should put teaching speaking on their list of priorities and provide courses on effective strategies for the development of speaking dimensions through implementing the main tenants of pushed output hypothesis.

Effect of surface treatment and type of cement on push-out bond strength of zirconium oxide posts.

Science.gov (United States)

Almufleh, Balqees S; Aleisa, Khalil I; Morgano, Steven M

2014-10-01

The effect of the surface treatment of zirconium oxide posts on their push-out bond strength is controversial. The purpose of this study was to compare the effects of 2 surface treatments on the bond strength of zirconium oxide posts cemented with different cements and to assess the failure mode. Seventy extracted human teeth were divided into 7 groups (n=10). Custom zirconium oxide posts (Cercon; Degudent) were fabricated for 6 groups. Posts in 3 groups were airborne-particle abraded (A). Posts in the other 3 groups were tribochemical silica coated (T). Three cements were used. Zinc phosphate cement was used to cement the zirconium oxide posts in groups AZ and TZ, RelyX ARC cement was used in groups ARA and TRA, and RelyX Unicem cement was used in groups ARU and TRU. Group C contained custom metal posts cemented with zinc phosphate cement. Specimens were horizontally sectioned into 3 sections and subjected to a push-out test. A mixed model analysis of variance, 1-way ANOVA, and the Tukey multiple comparison tests were used for statistical analysis. The highest push-out bond strength was recorded for Group ARU (21.03 MPa), and the lowest was recorded for Group ARA (7.57 MPa). No significant difference in push-out bond strength was found among the different surface treatments and root regions (P>.05). The type of cement had a significant effect on the push-out bond strength of zirconium oxide posts (P=.049). RelyX Unicem cement recorded (19.57 ±8.83 MPa) significantly higher push-out bond strength compared with zinc phosphate (9.95 ±6.31 MPa) and RelyX ARC cements (9.39 ±5.45 MPa). Adhesive failure at the post-cement interface was recorded for 75% of the posts cemented with zinc phosphate and RelyX ARC cements, while mixed failure was recorded for 75% of the posts cemented with RelyX Unicem cement. The type of cement used resulted in a statistically significant difference in the push-out bond strength of zirconium oxide posts, while both the surface treatment

Pushing the speed limit in enantioselective supercritical fluid chromatography.

Science.gov (United States)

Regalado, Erik L; Welch, Christopher J

2015-08-01

Chromatographic enantioseparations on the order of a few seconds can be achieved by supercritical fluid chromatography using short columns packed with chiral stationary phases. The evolution of 'world record' speeds for the chromatographic separation of enantiomers has steadily dropped from an industry standard of 20-40 min just two decades ago, to a current ability to perform many enantioseparations in well under a minute. Improvements in instrument and column technologies enabled this revolution, but the ability to predict optimal separation time from an initial method development screening assay using the t(min cc) predictor greatly simplifies the development and optimization of high-speed chiral chromatographic separations. In this study, we illustrate how the use of this simple tool in combination with the workhorse technique of supercritical fluid chromatography on customized short chiral columns (1-2 cm length) allows us to achieve ultrafast enantioseparations of pharmaceutically relevant compounds on the 5-20 s scale, bringing the technique of high-throughput enantiopurity analysis out of the specialist realm and into the laboratories of most researchers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Once-per-step control of ankle-foot prosthesis push-off work reduces effort associated with balance during walking.

Science.gov (United States)

Kim, Myunghee; Collins, Steven H

2015-05-01

Individuals with below-knee amputation have more difficulty balancing during walking, yet few studies have explored balance enhancement through active prosthesis control. We previously used a dynamical model to show that prosthetic ankle push-off work affects both sagittal and frontal plane dynamics, and that appropriate step-by-step control of push-off work can improve stability. We hypothesized that this approach could be applied to a robotic prosthesis to partially fulfill the active balance requirements of human walking, thereby reducing balance-related activity and associated effort for the person using the device. We conducted experiments on human participants (N = 10) with simulated amputation. Prosthetic ankle push-off work was varied on each step in ways expected to either stabilize, destabilize or have no effect on balance. Average ankle push-off work, known to affect effort, was kept constant across conditions. Stabilizing controllers commanded more push-off work on steps when the mediolateral velocity of the center of mass was lower than usual at the moment of contralateral heel strike. Destabilizing controllers enforced the opposite relationship, while a neutral controller maintained constant push-off work regardless of body state. A random disturbance to landing foot angle and a cognitive distraction task were applied, further challenging participants' balance. We measured metabolic rate, foot placement kinematics, center of pressure kinematics, distraction task performance, and user preference in each condition. We expected the stabilizing controller to reduce active control of balance and balance-related effort for the user, improving user preference. The best stabilizing controller lowered metabolic rate by 5.5% (p = 0.003) and 8.5% (p = 0.02), and step width variability by 10.0% (p = 0.009) and 10.7% (p = 0.03) compared to conditions with no control and destabilizing control, respectively. Participants tended to prefer stabilizing controllers

45-Day safety screening results for tank 241-U-102, push mode cores 143 and 144

International Nuclear Information System (INIS)

Steen, F.H.

1996-01-01

This document is the 45-day report deliverable for tank 241-U-102 push mode core segments collected between April 16, 1996 and May 6, 1996 and received by the 222-S Laboratory between April 17, 1996 and May 8, 1996. The segments were subsampled and analyzed in accordance, with the Tank 241-U-102 Push Mode Core Sampling and analysis Plan (TSAP) (Hu, 1996) and the Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995). The analytical results are included in Table 1. Attachment I is a cross reference to relate the tank farm identification numbers to the 222-S Laboratory LabCore sample numbers. The subsamples generated in the laboratory for analysis are identified in these diagrams with their sources shown. The diagram identifying the hydrostatic head fluid (HHF) blank is also included, Primary safety screening results and the raw data from Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) analyses are included in this report. Two of the samples submitted for DSC analysis exceeded notification limits as stated in the Safety Screening DQO (Dukelow, et al., 1995). Cyanide analysis was requested on these samples and a Reactive System Screening Tool analysis was requested for the sample exhibiting the highest exothenn in accordance with the TSAP (Hu, 1996). The results for these analyses will be reported in a revision to this document

Relationship between interstitial and blood glucose in type 1 diabetes patients: delay and the push-pull phenomenon revisited

NARCIS (Netherlands)

Wentholt, Iris M. E.; Hart, Augustus A. M.; Hoekstra, Joost B. L.; DeVries, J. Hans

2007-01-01

BACKGROUND: Interpretation of glucose sensor results requires clarification of the relationship between interstitial (IG) and blood (BG) glucose. We examined the delay of IG upon BG change and reinvestigated the push-pull phenomenon in type 1 diabetes patients. The push-pull phenomenon postulates

Effects of delayed pushing during the second stage of labor on postpartum fatigue and birth outcomes in nulliparous women.

Science.gov (United States)

Lai, Man-Lung; Lin, Kuan-Chia; Li, Hsin Yang; Shey, Kuang-Shing; Gau, Meei-Ling

2009-03-01

This article studied differences in postpartum fatigue and birth outcomes between women who pushed immediately and those who delayed pushing during the second stage of labor. Data were collected from primiparous women in their 38th to 42nd gestational week who did not receive epidural analgesia during labor and were free of complications during pregnancy. Using a quasi-experimental design, 72 participants selected by convenient sampling were assigned based on individual participant's preference to either an experimental or control group. For the experimental group, pushing was delayed until the point after full cervical dilation at which (a) the mother felt a strong physical pushing reflex, (b) the fetal head had both descended to at least the +1 level in the pelvis and turned to the occiput anterior position, and (c) uterine contractions were at least 30 mmHg. For the control group, the physician instructed mothers to begin pushing after full cervical dilation at the point when the fetal head was in the occiput anterior position and uterine contractions were at least 30 mmHg. The authors administered the Modified Fatigue Symptom Checklist at 1 and 24 hr after delivery to measure participant's fatigue levels. Birth outcomes were assessed based on medical chart data. Findings showed a significant difference between the two groups in terms of 1- and 24-hr postpartum fatigue scores. The duration of the second labor stage (experimental group, 70.31 +/- 37.17 min; control group, 129.06 +/- 75.69 min) also differed significantly. The group that pushed immediately recorded higher cesarean and instrument-assisted birth rates. No significant differences were observed in terms of perineal tears, maternal/neonatal complications, or neonatal Apgar scores. Results of this study provide important insights for caregivers working in the delivery room and suggest that current care procedures change to include the delayed pushing during the second stage of labor. By delaying pushing

Field evaluation of a push-pull system to reduce malaria transmission.

Directory of Open Access Journals (Sweden)

David J Menger

Full Text Available Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.

The effect of push factors in the leisure sports participation of the retired elderly on re-socialization recovery resilience.

Science.gov (United States)

Lee, Kwang-Uk; Kim, Hong-Rok; Yi, Eun-Surk

2014-04-01

This study aimed to provide useful materials for the realization of healthy and happy welfare society through the re-socialization of the retired elderly by identifying the effect of the push factors in the leisure sports participation of the retired elderly on re-socialization and recovery resilience. To achieve the study purpose, 304 subjects over the age of 55 residing in Seoul and Gyeonggin among the retired elderly were selected by using the method of systematic stratified cluster random sampling. As research methods, questionnaire papers were used. The data were collected and data which were judged to be incomplete or unreliable in responses were excluded from the analysis. After inputting data which are available to analysis and SPSS 18.0 program was used for statistical techniques. In this, data were processed by factor analysis, correlation analysis, and multiple regression analysis. The study results that were obtained from this analysis are as follows: First, the psychological stability among the push factors in the leisure sports participation of the elderly had a significant effect on re-socialization, while health pursuit had a significant effect on personal exchange and economic activity among the sub-factors of re-socialization. Second, psychological stability among the push factors in the leisure sports participation of the retired elderly had a significant effect on recovery resilience; personal relationships had an effect on empathy skills, impulse control, and self-efficacy; and health pursuit had a significant effect on impulse control, optimism, and self-efficacy.

Sample Preparation for Electron Probe Microanalysis-Pushing the Limits.

Science.gov (United States)

Geller, Joseph D; Engle, Paul D

2002-01-01

important, and, under certain conditions, may even be the limiting factor in the analytical uncertainty budget. This paper considers preparing samples to get known geometries. It will not address the analysis of samples with irregular, unprepared surfaces or unknown geometries.

Using Metaheuristic and Fuzzy System for the Optimization of Material Pull in a Push-Pull Flow Logistics Network

Directory of Open Access Journals (Sweden)

Afshin Mehrsai

2013-01-01

Full Text Available Alternative material flow strategies in logistics networks have crucial influences on the overall performance of the networks. Material flows can follow push, pull, or hybrid systems. To get the advantages of both push and pull flows in networks, the decoupling-point strategy is used as coordination mean. At this point, material pull has to get optimized concerning customer orders against pushed replenishment-rates. To compensate the ambiguity and uncertainty of both dynamic flows, fuzzy set theory can practically be applied. This paper has conceptual and mathematical parts to explain the performance of the push-pull flow strategy in a supply network and to give a novel solution for optimizing the pull side employing Conwip system. Alternative numbers of pallets and their lot-sizes circulating in the assembly system are getting optimized in accordance with a multi-objective problem; employing a hybrid approach out of meta-heuristics (genetic algorithm and simulated annealing and fuzzy system. Two main fuzzy sets as triangular and trapezoidal are applied in this technique for estimating ill-defined waiting times. The configured technique leads to smoother flows between push and pull sides in complex networks. A discrete-event simulation model is developed to analyze this thesis in an exemplary logistics network with dynamics.

Pushing the Conceptual Boundaries in Researching Religion in ...

African Journals Online (AJOL)

Consequently, key themes are evident in her work that would contribute significantly to the debates on religion in education in South Africa and abroad. The article covers the following themes in Roux's work: the significance of values in education and in collaborative research, the need for paradigm shifts for effective ...

Simulation of push-pull inverter using wide bandgap devices

Science.gov (United States)

Al-badri, Mustafa; Matin, Mohammed A.

2016-09-01

This paper discusses the use of wide bandgap devices (SiC-MOSFET) in the design of a push-pull inverter which provides inexpensive low power dc-ac inverters. The parameters used were 1200V SiC MOSFET(C2M0040120D) made by power company ROHM. This modeling was created using parameters that were provided from a device datasheet. The spice model is provided by this company to study the effect of adding this component on push-pull inverter ordinary circuit and compared results between SiC MOSFET and silicon MOSFET (IRFP260M). The results focused on Vout and Vmos stability as well as on output power and MOSFET power loss because it is a very crucial aspect on DC-AC inverter design. These results are done using the National Instrument simulation program (Multisim 14). It was found that power loss is better in the 12 and 15 vdc inverter. The Vout in the SIC MOSFET circuit shows more stability in the high current low resistance load in comparison to the Silicon MOSFET circuit and this will improve the overall performance of the circuit.

DESTINATION IMAGE OF BALI BASED ON THE PUSH MOTIVATIONAL FACTORS, IDENTITY AND DESTINATION CREATIONS IN THE PERSPECTIVE OF FOREIGN SENIOR TOURIST*

Directory of Open Access Journals (Sweden)

I Gusti Bagus Rai Utama

2016-03-01

Full Text Available The strength of the senior traveler segment is the high purchasing power the length of stay in a destination, making this market segment increasingly important in present and future. Consequently, this research aims to establish a model of motivation and its relationship with the image of Bali as an international tourism destination, especially from the perspective of senior tourists. This research employed survey method and utilized a combination of quantitative and qualitative analytical techniques. Factor analysis condensed various indicators into several key indicators to form a model with goodness of fit. Indicators representing push motivation variable include the improvement of health/fitness and the drive to perform physical exercise. Indicators representing destination identity variable include the culture and nature of Bali. Indicators representing destination creation variable include the service quality of travel agencies and service quality of travel guides. Indicators representing destination image variable include the image of cultural uniqueness and holiday atmosphere of Bali. The survey in this study involved 400 respondents of senior tourists, exclusively only foreign nationals. Goodness of fit is affirmed on the results of the analysis model, which answered the hypothesis that push motivation and destination creation affect destination images.

Giving the force direction : Analysis of speed skater push off forces with respect to an inertial coordinate system

NARCIS (Netherlands)

van der Kruk, E.; van der Helm, F.C.T.; Schwab, A.L.; Veeger, H.E.J.

2016-01-01

Pushoff in speed skating requires an extensive motion strategy. During speed skating the skater continuously changes the lean and steering angle of the skate and therewith the direction of push-off, The forces in an inertial coordinate system can give insight into what amount of the push-off force

Optimal Halbach permanent magnet designs for maximally pulling and pushing nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sarwar, A., E-mail: azeem@umd.edu [Fischell Department of Bioengineering, College Park, MD (United States); University of Maryland at College Park (United States); Nemirovski, A. [H. Milton Stewart School of Industrial and Systems Engineering (ISyE), Georgia Institute of Technology (United States); Shapiro, B. [Fischell Department of Bioengineering, College Park, MD (United States); Institute for Systems Research (United States); University of Maryland at College Park (United States)

2012-03-15

Optimization methods are presented to design Halbach arrays to maximize the forces applied on magnetic nanoparticles at deep tissue locations. In magnetic drug targeting, where magnets are used to focus therapeutic nanoparticles to disease locations, the sharp fall off of magnetic fields and forces with distances from magnets has limited the depth of targeting. Creating stronger forces at a depth by optimally designed Halbach arrays would allow treatment of a wider class of patients, e.g. patients with deeper tumors. The presented optimization methods are based on semi-definite quadratic programming, yield provably globally optimal Halbach designs in 2 and 3-dimensions, for maximal pull or push magnetic forces (stronger pull forces can collect nanoparticles against blood forces in deeper vessels; push forces can be used to inject particles into precise locations, e.g. into the inner ear). These Halbach designs, here tested in simulations of Maxwell's equations, significantly outperform benchmark magnets of the same size and strength. For example, a 3-dimensional 36 element 2000 cm{sup 3} volume optimal Halbach design yields a 5 Multiplication-Sign greater force at a 10 cm depth compared to a uniformly magnetized magnet of the same size and strength. The designed arrays should be feasible to construct, as they have a similar strength ({<=}1 T), size ({<=}2000 cm{sup 3}), and number of elements ({<=}36) as previously demonstrated arrays, and retain good performance for reasonable manufacturing errors (element magnetization direction errors {<=}5 Degree-Sign), thus yielding practical designs to improve magnetic drug targeting treatment depths. - Highlights: Black-Right-Pointing-Pointer Optimization methods presented to design Halbach arrays for drug targeting. Black-Right-Pointing-Pointer The goal is to maximize forces on magnetic nanoparticles at deep tissue locations. Black-Right-Pointing-Pointer The presented methods yield provably globally optimal Halbach

Optimal Halbach permanent magnet designs for maximally pulling and pushing nanoparticles

International Nuclear Information System (INIS)

Sarwar, A.; Nemirovski, A.; Shapiro, B.

2012-01-01

Optimization methods are presented to design Halbach arrays to maximize the forces applied on magnetic nanoparticles at deep tissue locations. In magnetic drug targeting, where magnets are used to focus therapeutic nanoparticles to disease locations, the sharp fall off of magnetic fields and forces with distances from magnets has limited the depth of targeting. Creating stronger forces at a depth by optimally designed Halbach arrays would allow treatment of a wider class of patients, e.g. patients with deeper tumors. The presented optimization methods are based on semi-definite quadratic programming, yield provably globally optimal Halbach designs in 2 and 3-dimensions, for maximal pull or push magnetic forces (stronger pull forces can collect nanoparticles against blood forces in deeper vessels; push forces can be used to inject particles into precise locations, e.g. into the inner ear). These Halbach designs, here tested in simulations of Maxwell's equations, significantly outperform benchmark magnets of the same size and strength. For example, a 3-dimensional 36 element 2000 cm 3 volume optimal Halbach design yields a 5× greater force at a 10 cm depth compared to a uniformly magnetized magnet of the same size and strength. The designed arrays should be feasible to construct, as they have a similar strength (≤1 T), size (≤2000 cm 3 ), and number of elements (≤36) as previously demonstrated arrays, and retain good performance for reasonable manufacturing errors (element magnetization direction errors ≤5°), thus yielding practical designs to improve magnetic drug targeting treatment depths. - Highlights: ► Optimization methods presented to design Halbach arrays for drug targeting. ► The goal is to maximize forces on magnetic nanoparticles at deep tissue locations. ► The presented methods yield provably globally optimal Halbach designs in 2D and 3D. ► These designs significantly outperform benchmark magnets of the same size and strength. ► These

Peaking for optimal performance: Research limitations and future directions.

Science.gov (United States)

Pyne, David B; Mujika, Iñigo; Reilly, Thomas

2009-02-01

A key element of the physical preparation of athletes is the taper period in the weeks immediately preceding competition. Existing research has defined the taper, identified various forms used in contemporary sport, and examined the prescription of training volume, load, intensity, duration, and type (progressive or step). Current limitations include: the lack of studies on team, combative, racquet, and precision (target) sports; the relatively small number of randomized controlled trials; the narrow focus on a single competition (single peak) compared with multiple peaking for weekly, multi-day or multiple events; and limited understanding of the physiological, neuromuscular, and biomechanical basis of the taper. Future research should address these limitations, together with the influence of prior training on optimal tapering strategies, and the interactions between the taper and long-haul travel, heat, and altitude. Practitioners seek information on how to prescribe tapers from season to season during an athlete's career, or a team's progression through a domestic league season, or multi-year Olympic or World Cup cycle. Practical guidelines for planning effective tapers for the Vancouver 2010 and London 2012 Olympics will evolve from both experimental investigations and modelling of successful tapers currently employed in a wide range of sports.

PRESSURE ULCERS ASSESSMENT THROUGH THE PRESSURE ULCER SCALE FOR HEALING APPLICATION (PUSH

Directory of Open Access Journals (Sweden)

Stefy Letícia Pessoa Silveira

2013-03-01

Full Text Available OBJETIVO: avaliar úlceras por pressão(UPP com enfoque na aplicação da escala PUSH. METODOLOGIA: Realizou-se entre setembro-outubro de 2010, estudo longitudinal prospectivo em três Unidades de Terapia Intensiva de um Hospital, Teresina, Piauí com amostra de 19 pacientes e 134 aplicações da PUSH, não probabilística por conveniência. RESULTADOS: caracterizada pelo predomínio de UPP no sexo feminino(52,6%, ≥ 80 anos(36,8% e cor parda(52,6%;. Prevaleceu cuidadores diretos-filhos(73,7%. Todos os pacientes apresentaram sonda vesical, incontinência intestinal, restrição ao leito com média de 1,18 anos (±5,18, limitações em 73,68% causada pela doença de base e 84,2% inconscientes. A prevalência de UPP foi 61,29%, das quais 63,33% localizadas na região sacral, grau II, 29,6% tratadas com óleo AGE. Houve queda ou manutenção dos escores da escala. CONCLUSÃO: a PUSH é útil na avaliação da cicatrização de feridas permitindo monitorar resultados globais e apresentando-se válida para integrar protocolos, a fim de implementar a assistência de enfermagem.

Trunk response and stability in standing under sagittal-symmetric pull-push forces at different orientations, elevations and magnitudes.

Science.gov (United States)

El Ouaaid, Z; Shirazi-Adl, A; Plamondon, A

2018-03-21

To reduce lifting and associated low back injuries, manual material handling operations often involve pulling-pushing of carts at different weights, orientations, and heights. The loads on spine and risk of injury however need to be investigated. The aim of this study was to evaluate muscle forces, spinal loads and trunk stability in pull-push tasks in sagittal-symmetric, static upright standing posture. Three hand-held load magnitudes (80, 120 and 160 N) at four elevations (0, 20, 40 and 60 cm to the L5-S1) and 24 force directions covering all pull/push orientations were considered. For this purpose, a musculoskeletal finite element model with kinematics measured earlier were used. Results demonstrated that peak spinal forces occur under inclined pull (lift) at upper elevations but inclined push at the lowermost one. Minimal spinal loads, on the other hand, occurred at and around vertical pull directions. Overall, spinal forces closely followed variations in the net external moment of pull-push forces at the L5-S1. Local lumbar muscles were most active in pulls while global extensor muscles in lifts. The trunk stability margin decreased with load elevation except at and around horizontal push; it peaked under pulls and reached minimum at vertical lifts. It also increased with antagonist activity in muscles and intra-abdominal pressure. Results provide insight into the marked effects of variation in the load orientation and elevation on muscle forces, spinal loads and trunk stability and hence offer help in rehabilitation, performance enhancement training and design of safer workplaces. Copyright © 2017 Elsevier Ltd. All rights reserved.

A push-pull system to reduce house entry of malaria mosquitoes

NARCIS (Netherlands)

Menger, D.J.; Otieno, B.; Rijk, de M.; Mukabana, W.R.; Loon, van J.J.A.; Takken, W.

2014-01-01

Background. Mosquitoes are the dominant vectors of pathogens that cause infectious diseases such as malaria, dengue, yellow fever and filariasis. Current vector control strategies often rely on the use of pyrethroids against which mosquitoes are increasingly developing resistance. Here, a push-pull

Sample Preparation for Electron Probe Microanalysis—Pushing the Limits

Science.gov (United States)

Geller, Joseph D.; Engle, Paul D.

2002-01-01

important, and, under certain conditions, may even be the limiting factor in the analytical uncertainty budget. This paper considers preparing samples to get known geometries. It will not address the analysis of samples with irregular, unprepared surfaces or unknown geometries. PMID:27446757

Push-out Bond Strength of Calcium Enriched Mixture Exposed to Alkaline Environment

Directory of Open Access Journals (Sweden)

Sobhnamayan F

2015-09-01

Full Text Available Statement of Problem: Calcium hydroxide which is commonly used as an intracanal medicament, changes the pH of dentin and periradicular tissues to an alkaline pH. In some clinical situations, endodontic reparative cements like calcium enriched mixture cement are used after calcium hydroxide therapy. However, the alkaline pH may affect the physical properties of this cement. Objectives: This study was designed to evaluate the effect of alkaline pH on the push-out bond strength of calcium enriched mixture. Materials and Methods: 80 root slices were prepared from single-rooted human teeth and their lumens were instrumented to achieve a diameter of 1.3mm. Calcium enriched mixture (CEM was mixed according to the manufacturer’s instruction and introduced into the lumens of root slices. The specimens were then randomly divided into 4 groups (n = 20 and wrapped in pieces of gauze soaked in synthetic tissue fluid (STF buffered in potassium hydroxide at pH values of 7.4, 8.4, 9.4, or 10.4. The samples were incubated for 4 days at 37°C. The push-out bond strengths were then measured using a universal testing machine. Failure modes were examined under a light microscope at ×20 magnification. The data were analyzed using one-way analysis of variance and Tukey’s post hoc tests. Results: The greatest (1.41 ± 0.193 MPa and lowest (0.8 ± 0.06 MPa mean push-out bond strengths were observed after exposure to pH values of 7.4 and 8.4, respectively. There were significant differences between the neutral group and the groups with pH of 8.4 (p = 0.008 and 10.4 (p = 0.022. The bond failure was predominantly of cohesive type for all experimental groups. Conclusions: Under the condition of this study, alkaline pH adversely affected the Push-out bond strength of CEM cement.

Three Levels of Push-Pull Dynamics among Chinese International Students' Decision to Study Abroad in the Canadian Context

Science.gov (United States)

Chen, Jun Mian

2017-01-01

The extant literature on student migration flows generally focus on the traditional push-pull factors of migration at the individual level. Such a tendency excludes the broader levels affecting international student mobility. This paper proposes a hybrid of three levels of push-pull dynamics (micro-individual decision-making, meso-academic…

Development of a sensorimotor algorithm able to deal with unforeseen pushes and its implementation based on VHDL

OpenAIRE

Lezcano Giménez, Pablo Gabriel

2015-01-01

Development of a Sensorimotor Algorithm Able to Deal with Unforeseen Pushes and Its Implementation Based on VHDL is the title of my thesis which concludes my Bachelor Degree in the Escuela Técnica Superior de Ingeniería y Sistemas de Telecomunicación of the Universidad Politécnica de Madrid. It encloses the overall work I did in the Neurorobotics Research Laboratory from the Beuth Hochschule für Technik Berlin during my ERASMUS year in 2015. This thesis is focused on the field of robotics, sp...

JavaScript programming pushing the limits

CERN Document Server

Raasch, Jon

2013-01-01

Take your JavaScript knowledge as far as it can go JavaScript has grown up, and it's a hot topic. Newer and faster JavaScript VMs and frameworks built upon them have increased the popularity of JavaScript for server-side web applications, and rich JS applications are being developed for mobile devices. This book delivers a compelling tutorial, showing you how to build a real-world app from the ground up. Experienced developers who want to master the latest techniques and redefine their skills will find this deep dive into JavaScript's hidden functionalities gives them the tools to

IMEC pushes the limits of CMOS

OpenAIRE

George Marsh

2002-01-01

An evolution that started with thermionic valve-based mainframe computers and can now put multiples of their processing power into a modern lap-top is today proceeding towards ambient intelligence, in which ever more compact processing will be all around us and, quite literally, part of the furniture. Convergence of information and communications technology (ICT), today exemplified by the conjunction of GSM (global system for mobile) telephony with ‘palm’ PC power, will go much further as mic...

Pushing XPath Accelerator to its Limits

OpenAIRE

Grün, Christian; Holupirek, Alexander; Kramis, Marc; Scholl, Marc H.; Waldvogel, Marcel

2006-01-01

Two competing encoding concepts are known to scale well with growing amounts of XML data: XPath Accelerator encoding implemented by MonetDB for in-memory documents and X-Hive's Persistent DOM for on-disk storage. We identified two ways to improve XPath Accelerator and present prototypes for the respective techniques: BaseX boosts in-memory performance with optimized data and value index structures while Idefix introduces native block-oriented persistence with logarithmic update behavior for t...

Pushing configuration-interaction to the limit

DEFF Research Database (Denmark)

Vogiatzis, Konstantinos D.; Ma, Dongxia; Olsen, Jeppe

2017-01-01

A new large-scale parallel multiconfigurational self-consistent field (MCSCF) implementation in the open-source NWChem computational chemistry code is presented. The generalized active space (GAS) approach is used to partition large configuration interaction (CI) vectors and generate a sufficient...

Autoethnography as a research method: Advantages, limitations and criticisms

Directory of Open Access Journals (Sweden)

Mariza G. Méndez

2014-01-01

Full Text Available The aim of this article is to review the literature  on autoethnography as a research method. It will first describe what is meant by autoethnography, or evocative narratives, and consider the particular features of this type of method. The paper will go on to explore the advantages, limitations and criticisms this research method has endured since its emergence during the 1980s. Finally, the different approaches to the evaluation of autoethnography will be reviewed.

Theoretical modelling of tip effects in the pushing manipulation of C60 on the Si(001) surface

International Nuclear Information System (INIS)

Martsinovich, N; Kantorovich, L

2008-01-01

We present the results of our theoretical studies on the repulsive (pushing) manipulation of a C 60 molecule on the Si(001) surface with several scanning tunnelling microscopy tips. We show that, for silicon tips, tip-C 60 bonds are formed even with tips that do not initially have dangling bonds, and this tip-C 60 interaction drives the manipulation of the molecule. The details of the atomic structure of the tip and its position relative to the molecule do not have a significant effect on the mechanism and the sequence of adsorption configurations during the pushing manipulation of C 60 along the trough, where the trough itself provides a guiding effect. The pushing manipulation is thus a very robust process that occurs largely independently of the tip structure. On the other hand, the pushing manipulation across an Si-Si dimer row into the neighbouring trough proceeds in a more complex way, with tip deformation and detachment more likely to occur. We demonstrate the role of tip deformation and tip-molecule bond rearrangement in the continuous manipulation of the molecule. Finally, we calculate and analyse the forces acting on the tip during manipulation and identify characteristic patterns

Push-Pull Laser-Atomic Oscillator

International Nuclear Information System (INIS)

Jau, Y.-Y.; Happer, W.

2007-01-01

A vapor of alkali-metal atoms in the external cavity of a semiconductor laser, pumped with a time-independent injection current, can cause the laser to self-modulate at the 'field-independent 0-0 frequency' of the atoms. Push-pull optical pumping by the modulated light drives most of the atoms into a coherent superposition of the two atomic sublevels with an azimuthal quantum number m=0. The atoms modulate the optical loss of the cavity at the sharply defined 0-0 hyperfine frequency. As in a maser, the system is not driven by an external source of microwaves, but a very stable microwave signal can be recovered from the modulated light or from the modulated voltage drop across the laser diode. Potential applications for this new phenomenon include atomic clocks, the production of long-lived coherent atomic states, and the generation of coherent optical combs

Evaluation of Interhandle Distance During Pushing and Pulling of a Four-Caster Cart for Upper Limb Exertion.

Science.gov (United States)

Ohnishi, Akihiro; Takanokura, Masato; Sugama, Atsushi

2016-09-01

This study examined the relationship between interhandle distances and upper limb exertion during simply pushing and pulling of a cart with four swivel wheels, defined by a roll box pallet (RBP) in a Japanese industrial standard. Six healthy young male participants were asked to push and pull an RBP at a distance of 5.2 m under six conditions corresponding to different interhandle distances (40 cm, 60 cm, and 80 cm) and weights (130 kg and 250 kg). The upper limb exertion was studied by shoulder abduction and flexion, and elbow flexion, as well as surface electromyogram (EMG) in shoulder extensor, and elbow flexor and extensor. Participants were required to provide subjective evaluations on operability after each trial. Subjective operability indicated that a narrower interhandle distance had a better operability for pushing. Interhandle distance was also related to upper limb exertion especially for pushing. A narrow interhandle distance caused smaller shoulder adduction but larger elbow flexion. The normalized EMG data revealed that muscular activity became smaller with a narrow interhandle distance in shoulder extensor. During the pulling task, elbow flexion was smaller at a narrow interhandle distance, although subjective operability and normalized EMG were not significantly varied. A wider interhandle distance, such as 80 cm, was not suitable in the forwardbackward movement of the RBP. Therefore, this study concluded that an interhandle distance of 40 cm would be suitable for pushing and pulling an RBP to protect the workers' hands against the risk of injury by installing inner handles.

Analysis of pushing exercises: muscle activity and spine load while contrasting techniques on stable surfaces with a labile suspension strap training system.

Science.gov (United States)

McGill, Stuart M; Cannon, Jordan; Andersen, Jordan T

2014-01-01

Labile surfaces in the form of suspension straps are increasingly being used as a tool in resistance training programs. Pushing is a common functional activity of daily living and inherently part of a well-rounded training program. This study examined pushing exercises performed on stable surfaces and unstable suspension straps, specifically muscle activation levels and spine loads were quantified together with the influence of employing technique coaching. There were several main questions that this study sought to answer: Which exercises challenged particular muscles? What was the magnitude of the resulting spine load? How did stable and unstable surfaces differ? Did coaching influence the results? Fourteen men were recruited as part of a convenience sample (mean age, 21.1 ± 2.0 years; height, 1.77 ± 0.06 m; mean weight, 74.6 ± 7.8 kg). Data were processed and input to a sophisticated and anatomically detailed 3D model that used muscle activity and body segment kinematics to estimate muscle force-in this way, the model was sensitive to the individuals choice of motor control for each task; muscle forces and linked segment joint loads were used to calculate spine loads. Exercises were performed using stable surfaces for hand/feet contact and repeated where possible with labile suspension straps. Speed of movement was standardized across participants with the use of a metronome for each exercise. There were gradations of muscle activity and spine load characteristics to every task. In general, the instability associated with the labile exercises required greater torso muscle activity than when performed on stable surfaces. Throughout the duration of an exercise, there was a range of compression; the TRX push-up ranged from 1,653 to 2,128.14 N, whereas the standard push-up had a range from 1,233.75 to 1,530.06 N. There was no significant effect of exercise on spine compression (F(4,60) = 0.86, p = 0.495). Interestingly, a standard push-up showed significantly

Ergonomic study regarding sport training – Push-ups simulation and analysis

Directory of Open Access Journals (Sweden)

Ion S. BOROZAN

2012-06-01

Full Text Available Some of the most common and helpful physical exercises used in sport training are the push-ups. Their biomechanics is analyzed in the paper and the author also gives an ergonomical study of this particular exercise with a complete simulation of the process.

N -annulated perylene-based push-pull-type sensitizers

KAUST Repository

Qi, Qingbiao; Wang, Xingzhu; Fan, Li; Zheng, Bin; Zeng, Wangdong; Luo, Jie; Huang, Kuo-Wei; Wang, Qing; Wu, Jishan

2015-01-01

Alkoxy-wrapped N-annulated perylene (NP) was synthesized and used as a rigid and coplanar π-linker for three push-pull type metal-free sensitizers QB1-QB3. Their optical and electrochemical properties were tuned by varying the structure of acceptor. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells, and power conversion efficiency up to 6.95% was achieved, indicating that NP could be used as a new building block for the design of high-performance sensitizers in the future.

N -annulated perylene-based push-pull-type sensitizers

KAUST Repository

Qi, Qingbiao

2015-02-06

Alkoxy-wrapped N-annulated perylene (NP) was synthesized and used as a rigid and coplanar π-linker for three push-pull type metal-free sensitizers QB1-QB3. Their optical and electrochemical properties were tuned by varying the structure of acceptor. These new dyes were applied in Co(II)/(III) based dye-sensitized solar cells, and power conversion efficiency up to 6.95% was achieved, indicating that NP could be used as a new building block for the design of high-performance sensitizers in the future.

Effect of Saline Pushing after Contrast Material Injection in Abdominal Multidetector Computed Tomography with the Use of Different Iodine Concentrations

International Nuclear Information System (INIS)

Tatsugami, F.; Matsuki, M.; Kani, H.; Tanikake, M.; Miyao, M.; Yoshikawa, S.; Narabayashi, I.

2006-01-01

Purpose: To investigate whether saline pushing after contrast material improves hepatic vascular and parenchymal enhancement, and to determine whether this technique permits decreased contrast material concentration. Material and Methods: 120 patients who underwent hepatic multidetector computed tomography were divided randomly into four groups (Groups A-D): receiving 100 ml of contrast material (300 mgI/ml) only (A) or with 50 ml of saline solution (B); or 100 ml of contrast material (350 mgI/ml) only (C) or with 50 ml of saline solution (D). Computed tomography (CT) values of the aorta in the arterial phase, the portal vein in the portal venous inflow phase, and the liver in the hepatic phase were measured. Visualization of the hepatic artery and the portal vein by 3D CT angiography was evaluated as well. Results: Although the enhancement values of the aorta were not improved significantly with saline pushing, they continued at a high level to the latter slices with saline pushing. The enhancement value of the portal vein increased significantly and CT portography was improved with saline pushing. The enhancement value of the liver was not improved significantly using saline pushing. In a comparison between groups B and C, the enhancement values of the aorta and portal vein and the visualization of CT arteriography and portography were not statistically different. Conclusion: The saline pushing technique can contribute to a decrease in contrast material concentration for 3D CT arteriography and portography

Full scale model push-off test of reinforced concrete block with 51 mm dia. deformed steel bars

International Nuclear Information System (INIS)

Aoyagi, Y.

1981-01-01

The conclusions of this study are as follows; (1) The equation previously derived from small scale specimens, to predict the shear strength of push-off specimens including both initially cracked and uncracked, can conservatively estimate the experimental data of full scale specimens to the same extent as small scale ones. (2) The equation previously derived from small scale specimens, to predict the shear strength of initially cracked push-off specimens with reinforcements inclined to the shear plane, agrees reasonably well with the experimental data of full scale speciemens. (3) The concrete strength and yield strength of reinforcement theoretically set the balanced reinforcement ratio of the shear area above which the shear strength of specimens is constant. (4) The theoretical shear strength of push-off specimens overestimates the experimental data by about 25%. (orig./HP)

Intense source of cold cesium atoms based on a two-dimensional magneto–optical trap with independent axial cooling and pushing

International Nuclear Information System (INIS)

Huang Jia-Qiang; Wu Chen-Fei; Wang Li-Jun; Yan Xue-Shu; Zhang Jian-Wei

2016-01-01

We report our studies on an intense source of cold cesium atoms based on a two-dimensional (2D) magneto–optical trap (MOT) with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam to extract a cold atomic beam. With the independent pushing beam, the atomic flux can be substantially optimized. The total atomic flux maximum obtained in the 2D-HP MOT is 4.02 × 10 10 atoms/s, increased by 60 percent compared to the traditional 2D + MOT in our experiment. Moreover, with the pushing power 10 μW and detuning 0 Γ , the 2D-HP MOT can generate a rather intense atomic beam with the concomitant light shift suppressed by a factor of 20. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with an FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied in detail. The experimental results are in good agreement with the theoretical model. (paper)

Dentoalveolar growth of patients with complete unilateral cleft lip and palate by early two-stage furlow and push-back method: preliminary results.

Science.gov (United States)

Kitagawa, Taiji; Kohara, Hiroshi; Sohmura, Taiji; Takahashi, Junzo; Tachimura, Takashi; Wada, Takeshi; Kogo, Mikihiko

2004-09-01

This study examined dentoalveolar growth changes prior to the time of palatoplasty up to 3 years of age by the early two-stage Furlow and push-back methods. Thirty-four Japanese patients with complete unilateral cleft lip and palate (UCLP) treated with either a two-stage Furlow procedure (Furlow group: seven boys, eight girls) from 1998 to 2002 or a push-back procedure (push-back group; 12 boys, 7 girls) from 1993 to 1997. Consecutive plaster models were measured by three-dimensional laser scanner, before primary palatoplasty, before hard palate closure (Furlow group only), and at 3 years of age. Bite measures were taken at 3 years of age. In the Furlow group, arch length, canine width, first and second deciduous molar width and cross-sectional area, and depth and volume at midpoint showed greater growth than in the push-back group. In the Furlow group, the crossbite score was also better than in the push-back group at 3 years of age. In comparison with the push-back group, inhibition of growth impediment in the anterior region was observed in the horizontal direction in the Furlow group. In the midregion, it was observed in the horizontal and vertical directions, and in the posterior region it was observed in the horizontal direction. The results demonstrate that the early two-stage Furlow method showed progressive alveolar growth. Therefore, the early two-stage Furlow method is a more beneficial procedure than the push-back method.

Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

International Nuclear Information System (INIS)

Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

1992-01-01

The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

Pushing the accelerator - speeding up drug research with accelerator mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Garner, R.C. E-mail: colin.garner@cbams.co.uk; Leong, D

2000-10-01

Accelerator mass spectrometry (AMS) is the most sensitive analytical method yet developed for elemental isotope analysis and has a broad range of applications. The measurement of {sup 14}C is of most interest to biomedical researchers but few studies have been reported using AMS in drug discovery and development. For biomedical use, {sup 14}C is incorporated into organic molecules by either radiosynthesis or biosynthetically and the isotope is used as a surrogate for the distribution of the radiolabelled molecule either in animal or human studies. The majority of users of {sup 14}C quantitate the radioactivity using decay counting usually with a liquid scintillation counter (LSC). Our Centre over the past 12 months has been evaluating and validating the use of AMS as an alternative detection method. In vitro spiking studies of human plasma with {sup 14}C-Fluconazole, a prescription antifungal drug has demonstrated an excellent correlation between AMS and LSC (correlation coefficient 0.999). Human Phase I clinical studies have been conducted with radioactive doses ranging from 120 Bq (7000 dpm) to 11 kBq (300 nCi) to provide mass balance, plasma concentration and radioactive metabolite profiling data. Limits of detection of 0.00022 Bq {sup 14}C-labelled drug/ml plasma have been accurately quantitated in a plasma background of 0.0078 Bq/ml (0.013 dpm/ml in a plasma background of 0.47 dpm/ml or 2.72 pMC in a background of 90.19 pMC)

Push-pull with recovery stage high-voltage DC converter for PV solar generator

Science.gov (United States)

Nguyen, The Vinh; Aillerie, Michel; Petit, Pierre; Pham, Hong Thang; Vo, Thành Vinh

2017-02-01

A lot of systems are basically developed on DC-DC or DC-AC converters including electronic switches such as MOS or bipolar transistors. The limits of efficiency are quickly reached when high output voltages and high input currents are needed. This work presents a new high-efficiency-high-step-up based on push-pull DC-DC converter integrating recovery stages dedicated to smart HVDC distributed architecture in PV solar energy production systems. Appropriate duty cycle ratio assumes that the recovery stage work with parallel charge and discharge to achieve high step-up voltage gain. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit and thus, low on-state resistance Rdson of the main switch can be adopted to reduce conduction losses. Thus, the efficiency of a basic DC-HVDC converter dedicated to renewable energy production can be further improved with such topology. A prototype converter is developed, and experimentally tested for validation.

Morphisms of Extensions of C*-algebras: Pushing Forward the Busby Invariant

DEFF Research Database (Denmark)

Eilers, Søren; Loring, Terry A.; Pedersen, Gert Kjærgård

1999-01-01

of varying severity, on the given vertical maps and describe the solutions in terms of push-outs and pull-backs of certain diagrams. Our characterization of the universal solution to one of the diagrams yields a concrete description of various amalgamated free products. This leads to new results about the K...

Modeling the impact of pedestrian behavior diversity on traffic dynamics at a crosswalk with push button

Science.gov (United States)

Xie, Dong-Fan; Zhao, Xiao-Mei; Li, Xin-Gang; Zhu, Tai-Lang

2016-01-01

Crosswalk with push button is prevalent in lots of cities for the purpose of promoting the efficiency of the crosswalk, and thus the delays of both vehicles and pedestrians can be reduced. This strategy has been confirmed to be effective in several developed countries. However, it is a pity that application of push button is aborted in some cities in China. In this work, diverse behaviors of vehicles and pedestrians are analyzed and discussed. Then, a microscopic model is developed by incorporating the interaction between vehicles and pedestrians. Numerical simulations are performed to reveal the characteristics of traffic flow and the efficiency of the signal control strategy. Also, the impacts of risker proportion and button reaction time, as well as the impacts of various behaviors as mass behavior, the patience of pedestrian and push button habit are investigated. It is expected that the results will be helpful to the strategy design of a signalized crosswalk in such developing countries as China.

Tank 241-B-203 push mode core sampling and analysis plan. Revision 1

International Nuclear Information System (INIS)

Jo, J.

1995-01-01

This Sampling and Analysis Plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for two push-mode core samples from tank 241-B-203 (B-203)

Tank 241-B-204 push mode core sampling and analysis plan. Revision 1

International Nuclear Information System (INIS)

Sasaki, L.M.

1995-01-01

This Sampling and Analysis Plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for two push-mode core samples from tank 241-B-204 (B-204)

Influences of palatoplasty by the push-back procedure on craniofacial morphology and growth.

Science.gov (United States)

Iwasaki, Hiroshi; Kudo, Motonori; Yamamoto, Yuko

2012-12-01

For patients with a cleft palate, the push-back procedure which accompanies posterior shifting of palatal flap is thought to be most effective way of. achieving adequate velopharyngeal function. In this study, we aimed to evaluate the influences of the push-back procedure on the craniofacial morphology and its growth. Using cephalometry we compared the craniofacial morphology and growth of three groups of Japanese children, living in the same region (Hokkaido, Japan). 1) 28 children (13 girls and 15 boys) with operated submucous cleft palates at the ages of 9 and 14 respectively. 2) 12 age-matched children (7 girls and 5 boys) with unoperated submucous cleft palates. 3) 60 age-matched non-cleft children (30 girls and 30 boys) with normal occlusion. None of them received dentofacial orthopaedic treatment. While the patients who had been operated on had significant differences in posterior upper facial height and inclination of the palatal plane when compared with non-cleft children or unoperated cleft children, they showed no statistically significant difference in anteroposterior positioning of anterior part of the maxilla, compared with the unoperated. The influences of palatoplasty by the push-back procedure with posterior positioning of the palatal flaps on craniofacial morphology are additional to the cleft palate, and of minor concern. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Security-Enhanced Push Button Configuration for Home Smart Control.

Science.gov (United States)

Han, Junghee; Park, Taejoon

2017-06-08

With the emergence of smart and converged home services, the need for the secure and easy interplay of various devices has been increased. Push Button Configuration (PBC) is one of the technologies proposed for easy set-up of a secure session between IT and consumer devices. Although the Wi-Fi Direct specification explicitly states that all devices must support the PBC method, its applicability is very limited. This is because the security vulnerability of PBC can be maliciously exploited so that attackers can make illegitimate sessions with consumer devices. To address this problem, this paper proposes a novel Security-enhanced PBC (SePBC) scheme with which we can uncover suspicious or malicious devices. The proposed mechanism has several unique features. First, we develop a secure handshake distance measurement protocol by preventing an adversary sitting outside the region from maliciously manipulating its distance to be fake. Second, it is compatible with the original Wi-Fi PBC without introducing a brand-new methodology. Finally, SePBC uses lightweight operations without CPU-intensive cryptography computation and employs inexpensive H/W. Moreover, it needs to incur little overhead when there is no attack. This paper also designs and implements the proposed SePBC in the real world. Our experimental results and analysis show that the proposed SePBC scheme effectively defeats attacks on PBC while minimizing the modification of the original PBC equipment.

A polynomial-time algorithm to design push plans for sensorless parts sorting

NARCIS (Netherlands)

Berg, de M.; Goaoc, X.; van der Stappen, A.F.

2005-01-01

We consider the efficient computation of sequences of push actions that simultaneously orient two different polygons. Our motivation for studying this problem comes from the observation that appropriately oriented parts admit simple sensorless sorting. We study the sorting of two polygonal parts by

Direct push driven in situ color logging tool (CLT): technique, analysis routines, and application

Science.gov (United States)

Werban, U.; Hausmann, J.; Dietrich, P.; Vienken, T.

2014-12-01

Direct push technologies have recently seen a broad development providing several tools for in situ parameterization of unconsolidated sediments. One of these techniques is the measurement of soil colors - a proxy information that reveals to soil/sediment properties. We introduce the direct push driven color logging tool (CLT) for real-time and depth-resolved investigation of soil colors within the visible spectrum. Until now, no routines exist on how to handle high-resolved (mm-scale) soil color data. To develop such a routine, we transform raw data (CIEXYZ) into soil color surrogates of selected color spaces (CIExyY, CIEL*a*b*, CIEL*c*h*, sRGB) and denoise small-scale natural variability by Haar and Daublet4 wavelet transformation, gathering interpretable color logs over depth. However, interpreting color log data as a single application remains challenging. Additional information, such as site-specific knowledge of the geological setting, is required to correlate soil color data to specific layers properties. Hence, we exemplary provide results from a joint interpretation of in situ-obtained soil color data and 'state-of-the-art' direct push based profiling tool data and discuss the benefit of additional data. The developed routine is capable of transferring the provided information obtained as colorimetric data into interpretable color surrogates. Soil color data proved to correlate with small-scale lithological/chemical changes (e.g., grain size, oxidative and reductive conditions), especially when combined with additional direct push vertical high resolution data (e.g., cone penetration testing and soil sampling). Thus, the technique allows enhanced profiling by means of providing another reproducible high-resolution parameter for analysis subsurface conditions. This opens potential new areas of application and new outputs for such data in site investigation. It is our intention to improve color measurements by means method of application and data

Synthesis and characterization of a push-pull terpolymer based on anthracene, fluorene and benzothiadiazole

Energy Technology Data Exchange (ETDEWEB)

Floriano, Ana Carolina; Silveira, Daiana Santos; Cristovan, Fernando Henrique, E-mail: carolina.floriano@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), Sao Jose dos Campos, SP (Brazil); Rosa, Gabriel Marques; Liao, Luciano Morais [Universidade Federal de Goias (UFG), Goiania, GO (Brazil); Piovessan, Erick [Universidade Federal de Uberlandia (UFU), MG (Brazil)

2016-07-01

Full text: The development of organic optoelectronic devices with higher efficiency required new forms of polymers with strong donor-acceptor character (D-A), called a push-pull polymers. Most studies of organic polymers used in optoelectronic applications are centered on poly(3-hexylthiophene) with high regioregularity. However, there are other polymers synthesized with monomers that enables the possibility to adapt its electrical and optical properties. Polyfluorene derivatives show interesting chemical and physical properties due to a rigid planar biphenyl unit that are easily substituted at the remote C-9 position, improving the its processability in relation to polyfluorene, so it can be can be processed by spin-coating and many others deposition techniques. Fluorene derivatives copolymers prepared with anthracene unit improve electrochemical properties and present good photo and electroluminescence properties, due to an enhancement of the system conjugation. The benzothiadiazole, known by their environmental stability, planarity and electron-withdrawing nature, are a promising molecule in push−pull type semiconducting polymers. In this study proceed with the terpolymer synthesis containing 9,9-Dihexylfluorene and anthracene as pushing unit and benzothiadiazole as pushing unit. Also we synthesized the poly(9,9-dihexylfluorene)-co-(anthracene) and poly(9,9- dihexylfluorene)-co-(benzothiadiazole) copolymers. The polymers were synthesized using Suzuki coupling and characterized by FT-IR spectroscopy that shows the characteristic monomer bands and the polymer formation were confirmed by {sup 1}H-NMR. Polymerization yield of three polymers were about 50-70%. Polymers present good solubility in common organic solvent such as chloroform. Terpolymer UV-Vis spectra revealed broadband absorbance from 300 to 680nm and absorption maximum at 441 nm. Finally, the preliminary results indicate that the push-pull terpolymer is a promising broadband absorbing polymer for

Synthesis and characterization of a push-pull terpolymer based on anthracene, fluorene and benzothiadiazole

International Nuclear Information System (INIS)

Floriano, Ana Carolina; Silveira, Daiana Santos; Cristovan, Fernando Henrique; Rosa, Gabriel Marques; Liao, Luciano Morais; Piovessan, Erick

2016-01-01

Full text: The development of organic optoelectronic devices with higher efficiency required new forms of polymers with strong donor-acceptor character (D-A), called a push-pull polymers. Most studies of organic polymers used in optoelectronic applications are centered on poly(3-hexylthiophene) with high regioregularity. However, there are other polymers synthesized with monomers that enables the possibility to adapt its electrical and optical properties. Polyfluorene derivatives show interesting chemical and physical properties due to a rigid planar biphenyl unit that are easily substituted at the remote C-9 position, improving the its processability in relation to polyfluorene, so it can be can be processed by spin-coating and many others deposition techniques. Fluorene derivatives copolymers prepared with anthracene unit improve electrochemical properties and present good photo and electroluminescence properties, due to an enhancement of the system conjugation. The benzothiadiazole, known by their environmental stability, planarity and electron-withdrawing nature, are a promising molecule in push−pull type semiconducting polymers. In this study proceed with the terpolymer synthesis containing 9,9-Dihexylfluorene and anthracene as pushing unit and benzothiadiazole as pushing unit. Also we synthesized the poly(9,9-dihexylfluorene)-co-(anthracene) and poly(9,9- dihexylfluorene)-co-(benzothiadiazole) copolymers. The polymers were synthesized using Suzuki coupling and characterized by FT-IR spectroscopy that shows the characteristic monomer bands and the polymer formation were confirmed by 1 H-NMR. Polymerization yield of three polymers were about 50-70%. Polymers present good solubility in common organic solvent such as chloroform. Terpolymer UV-Vis spectra revealed broadband absorbance from 300 to 680nm and absorption maximum at 441 nm. Finally, the preliminary results indicate that the push-pull terpolymer is a promising broadband absorbing polymer for

Mixel camera--a new push-broom camera concept for high spatial resolution keystone-free hyperspectral imaging.

Science.gov (United States)

Høye, Gudrun; Fridman, Andrei

2013-05-06

Current high-resolution push-broom hyperspectral cameras introduce keystone errors to the captured data. Efforts to correct these errors in hardware severely limit the optical design, in particular with respect to light throughput and spatial resolution, while at the same time the residual keystone often remains large. The mixel camera solves this problem by combining a hardware component--an array of light mixing chambers--with a mathematical method that restores the hyperspectral data to its keystone-free form, based on the data that was recorded onto the sensor with large keystone. A Virtual Camera software, that was developed specifically for this purpose, was used to compare the performance of the mixel camera to traditional cameras that correct keystone in hardware. The mixel camera can collect at least four times more light than most current high-resolution hyperspectral cameras, and simulations have shown that the mixel camera will be photon-noise limited--even in bright light--with a significantly improved signal-to-noise ratio compared to traditional cameras. A prototype has been built and is being tested.

At the limit of polychromatic microdiffraction

Energy Technology Data Exchange (ETDEWEB)

Ice, Gene E., E-mail: IceGE@ornl.gov [MST Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States); Pang, Judy W.L.; Larson, Bennett C.; Budai, John D.; Tischler, Jonathan Z. [MST Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118 (United States); Choi, Jae-Young [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Liu Wenjun; Liu Chian; Assoufid, Lahsen; Shu Deming; Khounsary, Ali [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

2009-10-25

With a high-energy 3rd generation source like the Advanced Photon Source (APS), it is possible to push the performance of polychromatic microdiffraction far beyond current levels and to approach the intrinsic limit of the technique based on sample damage and the diffraction limit of X-rays. We describe ongoing efforts to improve the spatial, temporal and momentum transfer resolution of polychromatic microdiffraction on beamline 34-ID-E at the APS. The goal of this effort is to provide high-resolution images of 3D crystal structures over sufficient volumes and with sufficient detail to clarify the underlying physics of inhomogeneous structure and evolution on mesoscopic length scales. The performance of a high-speed amorphous Si area detector system and the ongoing development of advanced focusing optics will be described and discussed in light of the ultimate limits set by the physics of X-rays and materials, and in light of opportunities to field specialized insertion devices and optics for polychromatic microdiffraction.

The impact of regulations, safety considerations and physical limitations on research progress at maximum biocontainment.

Science.gov (United States)

Shurtleff, Amy C; Garza, Nicole; Lackemeyer, Matthew; Carrion, Ricardo; Griffiths, Anthony; Patterson, Jean; Edwin, Samuel S; Bavari, Sina

2012-12-01

We describe herein, limitations on research at biosafety level 4 (BSL-4) containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT) are highly regulated due to their potential to pose a severe threat to public health and safety. All federal, state, city, and local regulations must be followed to obtain and maintain registration for the institution to conduct research involving BSAT. These include initial screening and continuous monitoring of personnel, controlled access to containment laboratories, accurate and current BSAT inventory records. Safety considerations are paramount in BSL-4 containment laboratories while considering the types of research tools, workflow and time required for conducting both in vivo and in vitro experiments in limited space. Required use of a positive-pressure encapsulating suit imposes tremendous physical limitations on the researcher. Successful mitigation of these constraints requires additional time, effort, good communication, and creative solutions. Test and evaluation of novel vaccines and therapeutics conducted under good laboratory practice (GLP) conditions for FDA approval are prioritized and frequently share the same physical space with important ongoing basic research studies. The possibilities and limitations of biomedical research involving microbial pathogens of biodefense concern in BSL-4 containment laboratories are explored in this review.

The Impact of Regulations, Safety Considerations and Physical Limitations on Research Progress at Maximum Biocontainment

Directory of Open Access Journals (Sweden)

Jean Patterson

2012-12-01

Full Text Available We describe herein, limitations on research at biosafety level 4 (BSL-4 containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT are highly regulated due to their potential to pose a severe threat to public health and safety. All federal, state, city, and local regulations must be followed to obtain and maintain registration for the institution to conduct research involving BSAT. These include initial screening and continuous monitoring of personnel, controlled access to containment laboratories, accurate and current BSAT inventory records. Safety considerations are paramount in BSL-4 containment laboratories while considering the types of research tools, workflow and time required for conducting both in vivo and in vitro experiments in limited space. Required use of a positive-pressure encapsulating suit imposes tremendous physical limitations on the researcher. Successful mitigation of these constraints requires additional time, effort, good communication, and creative solutions. Test and evaluation of novel vaccines and therapeutics conducted under good laboratory practice (GLP conditions for FDA approval are prioritized and frequently share the same physical space with important ongoing basic research studies. The possibilities and limitations of biomedical research involving microbial pathogens of biodefense concern in BSL-4 containment laboratories are explored in this review.

The Impact of Regulations, Safety Considerations and Physical Limitations on Research Progress at Maximum Biocontainment

Science.gov (United States)

Shurtleff, Amy C.; Garza, Nicole; Lackemeyer, Matthew; Carrion, Ricardo; Griffiths, Anthony; Patterson, Jean; Edwin, Samuel S.; Bavari, Sina

2012-01-01

We describe herein, limitations on research at biosafety level 4 (BSL-4) containment laboratories, with regard to biosecurity regulations, safety considerations, research space limitations, and physical constraints in executing experimental procedures. These limitations can severely impact the number of collaborations and size of research projects investigating microbial pathogens of biodefense concern. Acquisition, use, storage, and transfer of biological select agents and toxins (BSAT) are highly regulated due to their potential to pose a severe threat to public health and safety. All federal, state, city, and local regulations must be followed to obtain and maintain registration for the institution to conduct research involving BSAT. These include initial screening and continuous monitoring of personnel, controlled access to containment laboratories, accurate and current BSAT inventory records. Safety considerations are paramount in BSL-4 containment laboratories while considering the types of research tools, workflow and time required for conducting both in vivo and in vitro experiments in limited space. Required use of a positive-pressure encapsulating suit imposes tremendous physical limitations on the researcher. Successful mitigation of these constraints requires additional time, effort, good communication, and creative solutions. Test and evaluation of novel vaccines and therapeutics conducted under good laboratory practice (GLP) conditions for FDA approval are prioritized and frequently share the same physical space with important ongoing basic research studies. The possibilities and limitations of biomedical research involving microbial pathogens of biodefense concern in BSL-4 containment laboratories are explored in this review. PMID:23342380

Prospects of high-resolution resonant X-ray inelastic scattering studies on solid materials, liquids and gases at diffraction-limited storage rings

International Nuclear Information System (INIS)

Schmitt, Thorsten; Groot, Frank M. F. de; Rubensson, Jan-Erik

2014-01-01

Diffraction-limited storage rings will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size in resonant inelastic X-ray scattering (RIXS) experiments to new limits. In this article the types of improved soft X-ray RIXS studies that will become possible with these instrumental improvements are envisioned. The spectroscopic technique of resonant inelastic X-ray scattering (RIXS) will particularly profit from immensely improved brilliance of diffraction-limited storage rings (DLSRs). In RIXS one measures the intensities of excitations as a function of energy and momentum transfer. DLSRs will allow for pushing the achievable energy resolution, signal intensity and the sampled spot size to new limits. With RIXS one nowadays probes a broad range of electronic systems reaching from simple molecules to complex materials displaying phenomena like peculiar magnetism, two-dimensional electron gases, superconductivity, photovoltaic energy conversion and heterogeneous catalysis. In this article the types of improved RIXS studies that will become possible with X-ray beams from DLSRs are envisioned

Prediction Model of Mechanical Extending Limits in Horizontal Drilling and Design Methods of Tubular Strings to Improve Limits

Directory of Open Access Journals (Sweden)

Wenjun Huang

2017-01-01

Full Text Available Mechanical extending limit in horizontal drilling means the maximum horizontal extending length of a horizontal well under certain ground and down-hole mechanical constraint conditions. Around this concept, the constrained optimization model of mechanical extending limits is built and simplified analytical results for pick-up and slack-off operations are deduced. The horizontal extending limits for kinds of tubular strings under different drilling parameters are calculated and drawn. To improve extending limits, an optimal design model of drill strings is built and applied to a case study. The results indicate that horizontal extending limits are underestimated a lot when the effects of friction force on critical helical buckling loads are neglected. Horizontal extending limits firstly increase and tend to stable values with vertical depths. Horizontal extending limits increase faster but finally become smaller with the increase of horizontal pushing forces for tubular strings of smaller modulus-weight ratio. Sliding slack-off is the main limit operation and high axial friction is the main constraint factor constraining horizontal extending limits. A sophisticated installation of multiple tubular strings can greatly inhibit helical buckling and increase horizontal extending limits. The optimal design model is called only once to obtain design results, which greatly increases the calculation efficiency.

Inconsistent classification of pusher behaviour in stroke patients: a direct comparison of the Scale for Contraversive Pushing and the Burke Lateropulsion Scale.

Science.gov (United States)

Bergmann, Jeannine; Krewer, Carmen; Rieß, Katrin; Müller, Friedemann; Koenig, Eberhard; Jahn, Klaus

2014-07-01

To compare the classification of two clinical scales for assessing pusher behaviour in a cohort of stroke patients. Observational case-control study. Inpatient stroke rehabilitation unit. A sample of 23 patients with hemiparesis due to a unilateral stroke (1.6 ± 0.7 months post stroke). Immediately before and after three different interventions, the Scale for Contraversive Pushing and the Burke Lateropulsion Scale were applied in a standardized procedure. The diagnosis of pusher behaviour on the basis of the Scale for Contraversive Pushing and the Burke Lateropulsion Scale differed significantly (χ2 = 54.260, p Pushing (χ2 = 19.148, p Pushing, but pusher behaviour on the Burke Lateropulsion Scale. 64.5% (20 of 31) of them scored on the Burke Lateropulsion Scale on the standing and walking items only. The Burke Lateropulsion Scale is an appropriate alternative to the widely used Scale for Contraversive Pushing to follow-up patients with pusher behaviour (PB); it might be more sensitive to detect mild pusher behaviour in standing and walking. © The Author(s) 2014.

Design of a Push-Broom Multi-Beam Radiometer for Future Ocean Observations

DEFF Research Database (Denmark)

Cappellin, C.; Pontoppidan, K.; Nielsen, P. H.

2015-01-01

The design of a push-broom multi-beam radiometer for future ocean observations is described. The radiometer provides a sensitivity one order of magnitude higher than a traditional conical scanning radiometer, and has the big advantage of being fully stationary relative to the satellite platform...

Reducing risk of pressure sores: effects of watch prompts and alarm avoidance on wheelchair push-ups.

Science.gov (United States)

White, G W; Mathews, R M; Fawcett, S B

1989-01-01

People who use wheelchairs are at risk for developing pressure sores. Regular pressure relief, in the form of a wheelchair push-up, is one way to reduce the likelihood of pressure sores. We examined the effects of antecedent (i.e., instructions, audible prompts) and consequent (i.e., alarm avoidance) events on wheelchair push-ups, using a multiple baseline analysis with 2 participants with spina bifida. Results suggest that the combined procedure was more effective than either antecedent or consequent events alone, and there is some evidence suggesting maintenance of effects over time. PMID:2793635

Efficacy of an Ergonomic Ankle Support Aid for Squatting Position in Improving Pushing Skills and Birth Outcomes During the Second Stage of Labor: A Randomized Controlled Trial.

Science.gov (United States)

Lin, Yu-Ching; Gau, Meei-Ling; Kao, Ghi-Hwei; Lee, Hung-Chang

2018-03-16

The physical positions that are adopted by women during childbirth significantly impact their childbirth outcomes and experiences. Literature studies have associated using a squatting position with reduced childbirth pain and increased comfort and pushing efficiency. However, the major disadvantage of the squatting position is that women may lack the muscular fitness and stamina necessary to sustain this position for a long period. The aim of this study was to compare the pushing experiences and birth outcomes of three different pushing positions during the second stage of labor. A randomized controlled trial was conducted at a regional teaching hospital in northern Taiwan. Data were collected from 168 primiparous women during the 38th to 42nd gestational weeks. None of the participants received epidural analgesia during labor, and all were free of pregnancy and labor-related complications. During labor, after full cervical dilation and when the fetal head had descended to at least the +1 station and had turned to the occiput anterior position, the experimental group was asked to push in the squatting position while using the ergonomically designed ankle support. For purposes of comparison, Comparison Group A was asked to push in the squatting position without the use of the support, and Comparison Group B was asked to push in a standard semirecumbent position. All of the participants completed a demographic and obstetrics data sheet, the short-form McGill Pain Questionnaire, and the Labor Pushing Experience scale within 4 hours postpartum. In terms of delivery time, the duration between the start of pushing to crowning for the experimental group (squatting with ankle supports) averaged 25.79 minutes less (F = 6.02, p pushing to infant birth averaged 25.21 minutes less for the experimental group than for Comparison Group B (F = 6.14, p pushing experiences than the comparison groups (F = 14.69, p pushing, squatting with the aid of ergonomically designed ankle

Evaluation of the internal and external responsiveness of the Pressure Ulcer Scale for Healing (PUSH) tool for assessing acute and chronic wounds.

Science.gov (United States)

Choi, Edmond P H; Chin, Weng Yee; Wan, Eric Y F; Lam, Cindy L K

2016-05-01

To examine the internal and external responsiveness of the Pressure Ulcer Scale for Healing (PUSH) tool for assessing the healing progress in acute and chronic wounds. It is important to establish the responsiveness of instruments used in conducting wound care assessments to ensure that they are able to capture changes in wound healing accurately over time. Prospective longitudinal observational study. The key study instrument was the PUSH tool. Internal responsiveness was assessed using paired t-testing and effect size statistics. External responsiveness was assessed using multiple linear regression. All new patients with at least one eligible acute or chronic wound, enrolled in the Nurse and Allied Health Clinic-Wound Care programme between 1 December 2012 - 31 March 2013 were included for analysis (N = 541). Overall, the PUSH tool was able to detect statistically significant changes in wound healing between baseline and discharge. The effect size statistics were large. The internal responsiveness of the PUSH tool was confirmed in patients with a variety of different wound types including venous ulcers, pressure ulcers, neuropathic ulcers, burns and scalds, skin tears, surgical wounds and traumatic wounds. After controlling for age, gender and wound type, subjects in the 'wound improved but not healed' group had a smaller change in PUSH scores than those in the 'wound healed' group. Subjects in the 'wound static or worsened' group had the smallest change in PUSH scores. The external responsiveness was confirmed. The internal and external responsiveness of the PUSH tool confirmed that it can be used to track the healing progress of both acute and chronic wounds. © 2016 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

Multislice CT of the liver. Effects of contrast material pushed with saline solution on hepatic enhancement

International Nuclear Information System (INIS)

Sekiguchi, Ryuzo; Hayashi, Takayuki; Tsukamoto, Tatsuaki; Kuroki, Yoshinori; Nasu, Katsuhiro; Murakami, Koji; Nawano, Shigeru

2004-01-01

The purpose of this study was to evaluate the usefulness of a method of power injection of contrast material pushed with saline solution for hepatic multislice CT using a dual-head power injector. One hundred twenty-one patients who underwent multislice CT to detect liver metastases were divided into two groups, depending on the protocol of contrast material administration: 100 mL of non-ionic contrast material (370 mgI/mL) or 100 mL of the same contrast material pushed with 30 mL of saline solution. Both contrast material and saline solution were administered at a rate of 2.5 mL/sec using a dual-head power injector. Attenuation values for the two protocols were obtained from the liver, portal vein, and descending aorta. Hepatic enhancement above 50 Hounsfield unit (HU), which is needed for the diagnosis of liver metastases, was achieved in 76.5% of patients given 100 mL of contrast material and 92.5% of those given 100 mL of contrast material pushed with a 30 mL saline solution. In contingency-table analysis, the CT attenuation value of liver categorized as less than 50 HU or more than 50 HU, showed a good relation between the categorized group and the protocol (p=0.0437). In patients with a body weight of 50 kg or more, 100 mL of contrast material pushed with saline solution provided significantly better CT attenuation values in the liver (p=0.0113), portal vein (p=0.0094), and descending aorta (p=0.0394) than those provided by the injection of 100 mL of contrast material alone. When contrast material pushed with saline solution was used, CT attenuation values in the liver were significantly increased, especially in patients with a body weight of 50 kg or more. This technique will provide a decrease in the volume of contrast material administered and a potential decrease in the side effects of contrast material. (author)

Apical adaptation, sealing ability and push-out bond strength of five root-end filling materials

Directory of Open Access Journals (Sweden)

Pablo Andrés AMOROSO-SILVA

2014-08-01

Full Text Available This study compared the fluid filtration, adaptation to the root canal walls, and the push-out bond strength of two resin-based sealers and three calcium silicate-based retrograde filling materials. Fifty maxillary canines were shaped using manual instruments and the apical portion was sectioned. Retrograde cavities of 3-mm depth were prepared. The specimens were divided into five groups (n = 10: Sealer 26 (S26; MBPc (experimental; MTA; Portland cement with 20% zirconium oxide (PC/ZO, and Portland cement with 20% calcium tungstate (PC/CT. The fluid filtration was measured at 7 and 15 days. To evaluate the interfacial adaptation, sections of the teeth, 1 and 2 mm from the apex, were prepared and the percentage of gaps was calculated. The push-out bond strength at 2 mm from the apex was evaluated. Statistical analysis was performed using the ANOVA/Tukey’s test (p < 0.05. At 7 and 15 days (p = 0.0048, p = 0.006, the PC/CT group showed higher fluid filtration values when compared to other groups. At 1 mm from the apex, no statistical differences in the adaptation were found among the cements (p = 0.44. At 2 mm from the apex, the PC/ZO group presented statistically lower percentage of gaps than S26, MBPc, and MTA (p = 0.0007. The MBPc group showed higher push-out bond strength than other cements evaluated (p = 0.0008. The fluid filtration and interfacial adaptation of the calcium silicate-based cements were similar to those of the resin-based cements. The resinous cement MBPc showed superior push-out bond strength.

Simplified method of ''push-pull'' test data analysis for determining in situ reaction rate coefficients

International Nuclear Information System (INIS)

Haggerty, R.; Schroth, M.H.; Istok, J.D.

1998-01-01

The single-well, ''''push-pull'''' test method is useful for obtaining information on a wide variety of aquifer physical, chemical, and microbiological characteristics. A push-pull test consists of the pulse-type injection of a prepared test solution into a single monitoring well followed by the extraction of the test solution/ground water mixture from the same well. The test solution contains a conservative tracer and one or more reactants selected to investigate a particular process. During the extraction phase, the concentrations of tracer, reactants, and possible reaction products are measured to obtain breakthrough curves for all solutes. This paper presents a simplified method of data analysis that can be used to estimate a first-order reaction rate coefficient from these breakthrough curves. Rate coefficients are obtained by fitting a regression line to a plot of normalized concentrations versus elapsed time, requiring no knowledge of aquifer porosity, dispersivity, or hydraulic conductivity. A semi-analytical solution to the advective-dispersion equation is derived and used in a sensitivity analysis to evaluate the ability of the simplified method to estimate reaction rate coefficients in simulated push-pull tests in a homogeneous, confined aquifer with a fully-penetrating injection/extraction well and varying porosity, dispersivity, test duration, and reaction rate. A numerical flow and transport code (SUTRA) is used to evaluate the ability of the simplified method to estimate reaction rate coefficients in simulated push-pull tests in a heterogeneous, unconfined aquifer with a partially penetrating well. In all cases the simplified method provides accurate estimates of reaction rate coefficients; estimation errors ranged from 0.1 to 8.9% with most errors less than 5%

Direct Push supported geotechnical and hydrogeological characterisation of an active sinkhole area

Science.gov (United States)

Tippelt, Thomas; Vienken, Thomas; Kirsch, Reinhard; Dietrich, Peter; Werban, Ulrike

2017-04-01

Sinkholes represent a natural geologic hazard in areas where soluble layers are present in the subsurface. A detailed knowledge of the composition of the subsurface and its hydrogeological and geotechnical properties is essential for the understanding of sinkhole formation and propagation. This serves as base for risk evaluation and the development of an early warning system. However, site models often depend on data from drillings and surface geophysical surveys that in many cases cannot resolve the spatial distribution of relevant hydrogeological and geotechnical parameters sufficiently. Therefore, an active sinkhole area in Münsterdorf, Northern Germany, was investigated in detail using Direct Push technology, a minimally invasive sounding method. The obtained vertical high-resolution profiles of geotechnical and hydrogeological characteristics, in combination with Direct Push based sampling and surface geophysical measurements lead to a strong improvement of the geologic site model. The conceptual site model regarding sinkhole formation and propagation will then be tested based on the gathered data and, if necessary, adapted accordingly.

Optimization and application of blasting parameters based on the "pushing-wall" mechanism

Science.gov (United States)

Ren, Feng-yu; Sow, Thierno Amadou Mouctar; He, Rong-xing; Liu, Xin-rui

2012-10-01

The large structure parameter of a sublevel caving method was used in Beiminghe iron mine. The ores were generally lower than the medium hardness and easy to be drilled and blasted. However, the questions of boulder yield, "pushing-wall" accident rate, and brow damage rate were not effectively controlled in practical blasting. The model test of a similar material shows that the charge concentration of bottom blastholes in the sector is too high; the pushing wall is the fundamental reason for the poor blasting effect. One of the main methods to adjust the explosive distribution is to increase the length of charged blastholes. Therefore, the field tests with respect to increasing the length of uncharged blastholes were made in 12# stope of -95 subsection and 6# stope of Beiminghe iron mine. This paper took the test result of 12# stope as an example to analyze the impact of charge structure on blasting effect and design an appropriate blasting parameter that is to similar to No.12 stope.

Modelo híbrido pull-push en el sector de las telecomunicaciones

Directory of Open Access Journals (Sweden)

Cristian Arlex Trejos Taborda

2016-07-01

Full Text Available La industria de las telecomunicaciones cambia rápidamente y las barreras de entrada son bajas implicando que la supervivencia en el mercado sea un verdadero desafío para las empresas. En este artículo estudia como los sistemas Pull y Push pueden ser integrados a la cadena de abastecimiento en el sector de telecomunicaciones en Colombia. Se desarrolló un modelo hibrido Pull y Push utilizando dinámica de sistemas en aras de determinar los niveles óptimos y el costo mínimo de inventario, al igual que el nivel óptimo de prestación de servicio a los clientes. Los resultados de la investigación demuestran que el comportamiento del modelo híbrido permite dar respuesta a las necesidades del mercado y de la empresa a la vez, generando niveles de inventario que son mínimos y suficientes para cubrir la demanda.

NREL Research Pushes Perovskites Closer to Market | News | NREL

Science.gov (United States)

even get close-to the above-20% efficiencies dominated by silicon solar panels. NREL researcher Kai Zhu ; Perovskites have a couple of major benefits over silicon solar panels. The silicon technology requires a high as excellent semiconductors. This means perovskite panels are more flexible than rigid silicon panels

Second-language acquisition research in the laboratory: possibilities and limitations

NARCIS (Netherlands)

Hulstijn, J.H.

1997-01-01

This paper discusses some possibilities and limitations of laboratory research methods for testing theories of second language acquisition. The paper includes a review of 20 experimental lab studies. The review focuses on the motivation for conducting lab studies, the use of artificial or

Metabolic cost of level-ground walking with a robotic transtibial prosthesis combining push-off power and nonlinear damping behaviors: preliminary results.

Science.gov (United States)

Yanggang Feng; Jinying Zhu; Qining Wang

2016-08-01

Recent advances in robotic technology are facilitating the development of robotic prostheses. Our previous studies proposed a lightweight robotic transtibial prosthesis with a damping control strategy. To improve the performance of power assistance, in this paper, we redesign the prosthesis and improve the control strategy by supplying extra push-off power. A male transtibial amputee subject volunteered to participate in the study. Preliminary experimental results show that the proposed prosthesis with push-off control improves energy expenditure by a percentage ranged from 9.72 % to 14.99 % for level-ground walking compared with the one using non-push-off control.

Evaluation of methods to assess push/pull forces in a construction task

NARCIS (Netherlands)

Hoozemans, M J; Van Der Beek, Allard J.; Frings-Dresena, M H; Van der Molen, Henk F.

2001-01-01

The objective of the present study was to determine the validity of methods to assess push/pull forces exerted in a construction task. Forces assessed using a hand-held digital force gauge were compared to those obtained using a highly accurate measuring frame. No significant differences were found

Control and Modeling of Push-Pull Forward Three-Level Converter for Microgrid

DEFF Research Database (Denmark)

Yao, Zhilei; Xu, Jing; Guerrero, Josep M.

2015-01-01

Renewable energy sources are widely used in microgrid. Output voltage of them is often low and varies widely. Because diodes in three-level legs in traditional three-level (TL) converter are substituted by MOSFETs, the push-pull forward (PPF) TL converter is very suitable for wide and low...

Thermal ionization mass spectrometry (TIMS) of actinides: Pushing the limits of accuracy and detection

Energy Technology Data Exchange (ETDEWEB)

Buerger, Stefan; Boulyga, Sergei; Cunningham, Alan; Klose, Dilani; Koepf, Andreas; Poths, Jane [Safeguards Analytical Laboratory, International Atomic Energy Agency, Vienna (Austria); Richter, Stephan [Institute for Reference Materials and Measurements, JRC-EU, Geel (Belgium)

2010-07-01

New method developments in multi-collector thermal ionization mass spectrometry (MC-TIMS) for actinide isotope ratio analysis to improve accuracy and limits of detection will be presented. With respect to limits of detection, results on improving work function using various carbon additives will be reviewed and presented as well as developments in cavity ion source (as compared to standard flat ribbon filament ion source) for femto- and attogram levels of uranium, plutonium, and americium. With respect to accuracy, results on isotope ratio measurements of isotopes of uranium (relative accuracy of 0.3% to 0.01%) are presented with an example being U-234-Th-230 age-dating (NBL CRM 112-A). In this context, the importance of traceability (to the S.I. units) and the use of (certified) reference materials are emphasized. The focus of this presentation is on applications to nuclear safeguards / forensics.

Research in Mobile Database Query Optimization and Processing

Directory of Open Access Journals (Sweden)

Agustinus Borgy Waluyo

2005-01-01

Full Text Available The emergence of mobile computing provides the ability to access information at any time and place. However, as mobile computing environments have inherent factors like power, storage, asymmetric communication cost, and bandwidth limitations, efficient query processing and minimum query response time are definitely of great interest. This survey groups a variety of query optimization and processing mechanisms in mobile databases into two main categories, namely: (i query processing strategy, and (ii caching management strategy. Query processing includes both pull and push operations (broadcast mechanisms. We further classify push operation into on-demand broadcast and periodic broadcast. Push operation (on-demand broadcast relates to designing techniques that enable the server to accommodate multiple requests so that the request can be processed efficiently. Push operation (periodic broadcast corresponds to data dissemination strategies. In this scheme, several techniques to improve the query performance by broadcasting data to a population of mobile users are described. A caching management strategy defines a number of methods for maintaining cached data items in clients' local storage. This strategy considers critical caching issues such as caching granularity, caching coherence strategy and caching replacement policy. Finally, this survey concludes with several open issues relating to mobile query optimization and processing strategy.

Pushing and pulling in relation to musculoskeletal disorders : a review of risk factors

NARCIS (Netherlands)

Hoozemans, M J; Van Der Beek, Allard J.; Frings-Dresen, M. H. W.; Dijk, F.J.H.; van der Woude, L H

The objective was to review the literature on risk factors for musculoskeletal disorders related to pushing and pulling. The risk factors have been described and evaluated from four perspectives: epidemiology, psychophysics, physiology, and biomechanics. Epidemiological studies have shown, based on

Pushing and pulling in relation to musculoskeletal disorders: a review of risk factors

NARCIS (Netherlands)

Hoozemans, Marco; van der Beek, A.J.; Frings-Dresen, M.H.W.; Dijk, F.J.H.

1998-01-01

The objective was to review the literature on risk factors for musculoskeletal disorders related to pushing and pulling. The risk factors have been described and evaluated from four perspectives: epidemiology, psychophysics, physiology, and biomechanics. Epidemiological studies have shown, based on

Contribution of sensory feedback to plantar flexor muscle activation during push-off in adults with cerebral palsy

DEFF Research Database (Denmark)

Frisk, Rasmus F.; Jensen, Peter; Kirk, Henrik

2017-01-01

applied unload perturbations at the ankle, thereby removing sensory feedback naturally activated during push-off. Reduction of electromyographic (EMG) activity in the soleus muscle caused by unloads was compared and related to kinematics and ankle joint stiffness measurements. Similar measures were...... feedback to ongoing soleus muscle activation during push-off than uninjured individuals. Increased passive stiffness around the ankle joint is likely to diminishn sensory feedback during gait, and/or sensory feedback is less integrated with central motor commands in the activation of spinal motor neurons...

Introducing Evidence Through Research "Push": Using Theory and Qualitative Methods.

Science.gov (United States)

Morden, Andrew; Ong, Bie Nio; Brooks, Lauren; Jinks, Clare; Porcheret, Mark; Edwards, John J; Dziedzic, Krysia S

2015-11-01

A multitude of factors can influence the uptake and implementation of complex interventions in health care. A plethora of theories and frameworks recognize the need to establish relationships, understand organizational dynamics, address context and contingency, and engage key decision makers. Less attention is paid to how theories that emphasize relational contexts can actually be deployed to guide the implementation of an intervention. The purpose of the article is to demonstrate the potential role of qualitative research aligned with theory to inform complex interventions. We detail a study underpinned by theory and qualitative research that (a) ensured key actors made sense of the complex intervention at the earliest stage of adoption and (b) aided initial engagement with the intervention. We conclude that using theoretical approaches aligned with qualitative research can provide insights into the context and dynamics of health care settings that in turn can be used to aid intervention implementation. © The Author(s) 2015.

Neonatal outcomes of deliveries in occiput posterior position when delayed pushing is practiced: a cohort study.

Science.gov (United States)

Dahlqvist, Kristina; Jonsson, Maria

2017-11-14

To examine the impact of occiput posterior position, compared to occiput anterior position, on neonatal outcomes in a setting where delayed pushing is practiced. The specific aim was to estimate the risk of acidaemia. Cohort study from a university hospital in Sweden between 2004 and 2012. Information was collected from a local database of 35,546 births. Umbilical artery sampling was routine. Outcomes were: umbilical artery pH pushing, birth in occiput posterior compared with anterior position is not associated with acidaemia. The higher risk of neonatal morbidity is of concern and any long-term consequences need to be investigated in future studies.

Evaluation of the resin cement thicknesses and push-out bond strengths of circular and oval fiber posts in oval-shapes canals

Science.gov (United States)

Er, Özgür; Kılıç, Kerem; Kılınç, Halil İbrahim; Sağsen, Burak

2015-01-01

PURPOSE The aim of this study was to evaluate whether the push-out bond strength varies between oval and circular fiber posts, and to examine the effect on the resin cement thicknesses around the posts. MATERIALS AND METHODS Eighteen mandibular premolar roots were separated into two groups for oval and circular fiber posts systems. Post spaces were prepared and fiber posts were luted to the post spaces. Roots were cut horizontally to produce 1-mm-thick specimens. Resin cement thicknesses were determined with a metallographic optical microscope and push-out tests were done. RESULTS No significant differences were observed in terms of push-out bond strength between the oval and circular fiber posts (P>.05) The resin cement thicknesses of the oval posts were greater than those of the circular posts group in the coronal, middle and apical specimens (P<.05). CONCLUSION In the light of these results, it can be stated that resin cement thickness does not affect the push-out bond strength. PMID:25722832

Ion Concentration- and Voltage-Dependent Push and Pull Mechanisms of Potassium Channel Ion Conduction.

Directory of Open Access Journals (Sweden)

Kota Kasahara

Full Text Available The mechanism of ion conduction by potassium channels is one of the central issues in physiology. In particular, it is still unclear how the ion concentration and the membrane voltage drive ion conduction. We have investigated the dynamics of the ion conduction processes in the Kv1.2 pore domain, by molecular dynamics (MD simulations with several different voltages and ion concentrations. By focusing on the detailed ion movements through the pore including selectivity filter (SF and cavity, we found two major conduction mechanisms, called the III-IV-III and III-II-III mechanisms, and the balance between the ion concentration and the voltage determines the mechanism preference. In the III-IV-III mechanism, the outermost ion in the pore is pushed out by a new ion coming from the intracellular fluid, and four-ion states were transiently observed. In the III-II-III mechanism, the outermost ion is pulled out first, without pushing by incoming ions. Increases in the ion concentration and voltage accelerated ion conductions, but their mechanisms were different. The increase in the ion concentrations facilitated the III-IV-III conductions, while the higher voltages increased the III-II-III conductions, indicating that the pore domain of potassium channels permeates ions by using two different driving forces: a push by intracellular ions and a pull by voltage.

Spanish translation and validation of the Scale for Contraversive Pushing to measure pusher behaviour.

Science.gov (United States)

Martín-Nieto, A; Atín-Arratibel, M Á; Bravo-Llatas, C; Moreno-Bermejo, M I; Martín-Casas, P

2018-06-08

The aim of this study was to develop and validate a Spanish-language version of the Scale for Contraversive Pushing, used to diagnose and measure pusher behaviour in stroke patients. Translation-back translation was used to create the Spanish-language Scale for Contraversive Pushing; we subsequently evaluated its validity and reliability by administering it to a sample of patients. We also analysed its sensitivity to change in patients identified as pushers who received neurological physiotherapy. Experts indicated that the content of the scale was valid. Internal consistency was very good (Cronbach's alpha of 0.94). The intraclass correlation coefficient showed high intra- and interobserver reliability (0.999 and 0.994, respectively). The Kappa and weighted Kappa coefficients were used to measure the reliability of each item; the majority obtained values above 0.9. Lastly, the differences between baseline and final evaluations of pushers were significant (paired sample t test), showing that the scale is sensitive to changes obtained through physical therapy. The Spanish-language version of the Scale for Contraversive Pushing is valid and reliable for measuring pusher behaviour in stroke patients. In addition, it is able to evaluate the ongoing changes in patients who have received physical therapy. Copyright © 2018 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

'We don´t want to be pushed by outsiders' the international ...

African Journals Online (AJOL)

It is argued that the IAAF´s organisational readmission strategy went through three phases. Firstly, it followed the overall policies of the International Olympics Committee (IOC) by taking a careful approach guided by African IAAF Council members; then it pushed South Africa towards participation in the 1991 Athletics World ...

"Push as hard as you can" instruction for telephone cardiopulmonary resuscitation: a randomized simulation study.

Science.gov (United States)

van Tulder, Raphael; Roth, Dominik; Havel, Christof; Eisenburger, Philip; Heidinger, Benedikt; Chwojka, Christof Constantin; Novosad, Heinz; Sterz, Fritz; Herkner, Harald; Schreiber, Wolfgang

2014-03-01

The medical priority dispatch system (MPDS®) assists lay rescuers in protocol-driven telephone-assisted cardiopulmonary resuscitation (CPR). Our aim was to clarify which CPR instruction leads to sufficient compression depth. This was an investigator-blinded, randomized, parallel group, simulation study to investigate 10 min of chest compressions after the instruction "push down firmly 5 cm" vs. "push as hard as you can." Primary outcome was defined as compression depth. Secondary outcomes were participants exertion measured by Borg scale, provider's systolic and diastolic blood pressure, and quality values measured by the skill-reporting program of the Resusci(®) Anne Simulator manikin. For the analysis of the primary outcome, we used a linear random intercept model to allow for the repeated measurements with the intervention as a covariate. Thirteen participants were allocated to control and intervention. One participant (intervention) dropped out after min 7 because of exhaustion. Primary outcome showed a mean compression depth of 44.1 mm, with an inter-individual standard deviation (SDb) of 13.0 mm and an intra-individual standard deviation (SDw) of 6.7 mm for the control group vs. 46.1 mm and a SDb of 9.0 mm and SDw of 10.3 mm for the intervention group (difference: 1.9; 95% confidence interval -6.9 to 10.8; p = 0.66). Secondary outcomes showed no difference for exhaustion and CPR-quality values. There is no difference in compression depth, quality of CPR, or physical strain on lay rescuers using the initial instruction "push as hard as you can" vs. the standard MPDS(®) instruction "push down firmly 5 cm." Copyright © 2014 Elsevier Inc. All rights reserved.

Operational limits and conditions and operating procedures for research reactors. Safety guide

International Nuclear Information System (INIS)

2008-01-01

This publication provides practical guidance on all important aspects of developing, formulating and presenting the operational limits and conditions as well as the operating procedures for research reactors. It covers the concept of operational limits and conditions, their content, and the responsibilities of the operating organization with respect to their establishment, modification, documentation and compliance. The guidance also covers the training of operating personnel on performing periodic testing, established by the operational limits and conditions, and operating procedures

Breaking bad news revisited: the push for negotiated disclosure and changing practice implications.

Science.gov (United States)

Arber, Anne; Gallagher, Ann

2003-04-01

This article revisits the ethical, legal, professional and emotional issues involved with disclosing bad news. The authors examine the push for disclosure that has come from a number of quarters in the UK, including ethical and legal challenges, in particular the Bristol Royal Inquiry Report, professional codes of conduct, health policy and the expectations of the public. The contribution of nurses to breaking bad news is not widely discussed in the literature. With the development of new nursing roles and evidence-based practice it is timely to consider the role of nurses in this process. The article highlights some limitations with current guidelines for breaking bad news, in particular, that these guidelines tend to be constructed from a professional standpoint and lack patient-centred evidence. The issue of emotional labour and how it relates to giving bad news is discussed with respect to professional staff and patients. The article concludes by raising some practice implications, including: the importance of context and continuity; the significance of information and support; the desirable qualities of the professional; and issues to consider in determining patient preferences.

Push-back technique facilitates ultra-low anterior resection without nerve injury in total mesorectal excision for rectal cancer.

Science.gov (United States)

Inoue, Yasuhiro; Hiro, Junichiro; Toiyama, Yuji; Tanaka, Koji; Uchida, Keiichi; Miki, Chikao; Kusunoki, Masato

2011-01-01

To describe our push-back approach to ultra-low anterior resection using the concept of the mucosal stump. We mobilize the rectum using an abdominal approach, and perform mucosal cutting circumferentially at the dentate line. The mucosal stump is closed, and the internal sphincteric muscle resected partially or totally according to tumor location. Perianal dissection is performed along the medial plane of the external sphincteric muscles, and the hiatal ligament is dissected posteriorly. To resect the entire rectum, the closed rectal stump is pushed back to the abdominal cavity using composed gauze. This prevents injury to the autonomic nerve. We performed colonic J-pouch anal anastomosis using our mucosal stump approach in 58 patients with rectal cancer located push-back approach for internal sphincter resection produces satisfactory functional and oncological results in ultra-low anterior rectal cancer. Copyright © 2011 S. Karger AG, Basel.

Effect of Endodontic Retreatment on Push-out Bond Strength and Quality of Fiber Postbonding Interface of Resin Cements.

Science.gov (United States)

Pelegrine, Rina Andréa; Paulillo, Luís Alexandre Maffei Sartini; Kato, Augusto Shoji; Fontana, Carlos Eduardo; Pinheiro, Sérgio Luiz; De Martin, Alexandre Sigrist; Bueno, Carlos Eduardo da Silveira

2016-01-01

The aim of this study is to evaluate the impact of endodontic retreatment on push-out bond strength and dentin interface of two resin cements used for fiber postcementation during endodontic retreatment. The root canals of 40 extracted human canines were prepared, obturated and divided into four groups (n = 10). Gutta-percha was partially removed and fiber posts were immediately cemented in groups 1 and 2 using Panavia F with ED Primer and RelyX™ U200, respectively. In groups 3 and 4, the root canal access was sealed with temporary restorative cement, specimens were stored for 30 days, endodontically retreated, and fiber posts were cemented using the resin cements applied to groups 1 and 2, respectively. Push-out tests and scanning electron microscopy analyses of different areas were performed. Data from push-out bond strengths were analyzed by one-way analysis of variance and Tukey's tests. Higher bond strength values were detected in the apical third for group 1 than group 3 (p 0.05). Comparisons between different thirds in the same group revealed a higher bond strength in the apical third for group 1. Scanning electron microscopy showed formation of hybrid layer and extensive resin tags in group 1. No hybrid layer was observed in groups 2 and 4. Endodontic retreatment had adverse effects on the push-out bond strength and dentinal interface of Panavia F with ED Primer when used for fiber postcementation specifically in the apical third, but not on RelyX™ U200. A significant interaction was detected between endodontic retreatment and resin cement, which indicated that endodontic retreatment might adversely affect the push-out bond strength and dentinal interface of Panavia F with ED Primer when used for fiber postcementation specifically in the apical third.

Cyclic Fiber Push-In Test Monitors Evolution of Interfacial Behavior in Ceramic Matrix Composites

Science.gov (United States)

Eldridge, Jeffrey I.

1998-01-01

SiC fiber-reinforced ceramic matrix composites are being developed for high-temperature advanced jet engine applications. Obtaining a strong, tough composite material depends critically on optimizing the mechanical coupling between the reinforcing fibers and the surrounding matrix material. This has usually been accomplished by applying a thin C or BN coating onto the surface of the reinforcing fibers. The performance of these fiber coatings, however, may degrade under cyclic loading conditions or exposure to different environments. Degradation of the coating-controlled interfacial behavior will strongly affect the useful service lifetime of the composite material. Cyclic fiber push-in testing was applied to monitor the evolution of fiber sliding behavior in both C- and BN-coated small-diameter (15-mm) SiC-fiber-reinforced ceramic matrix composites. The cyclic fiber push-in tests were performed using a desktop fiber push-out apparatus. At the beginning of each test, the fiber to be tested was aligned underneath a 10- mm-diameter diamond punch; then, the applied load was cycled between selected maximum and minimum loads. From the measured response, the fiber sliding distance and frictional sliding stresses were determined for each cycle. Tests were performed in both room air and nitrogen. Cyclic fiber push-in tests of C-coated, SiC-fiber-reinforced SiC showed progressive increases in fiber sliding distances along with decreases in frictional sliding stresses for continued cycling in room air. This rapid degradation in interfacial response was not observed for cycling in nitrogen, indicating that moisture exposure had a large effect in immediately lowering the frictional sliding stresses of C-coated fibers. These results indicate that matrix cracks bridged by C-coated fibers will not be stable, but will rapidly grow in moisture-containing environments. In contrast, cyclic fiber push-in tests of both BN-coated, SiC-fiber-reinforced SiC and BNcoated, Si

Mechanical load on the low back and shoulders during pushing and pulling of two-wheeled waste containers compared with lifting and carrying of bags and bins.

Science.gov (United States)

Schibye, B; Søgaard, K; Martinsen, D; Klausen, K

2001-08-01

Compare the mechanical load on the low back and shoulders during pushing and pulling a two-wheeled container with the load during lifting and carrying the same amount of waste. Only little is known about risk factors and mechanical loads during push/pull operations. A complete 2(3) factor push/pull experiment. A two-wheeled container with 25 or 50 kg was pushed in front of and pulled behind the body by seven waste collectors. Further, the same subjects lifted and carried a paper bag and a dustbin both loaded with 7 and 25 kg. All operations were video recorded and the push/pull force was measured by means of a three-dimensional force transducer. Peak Motus and Watbak software were used for digitising and calculation of torque at L4/L5 and the shoulder joints and compression and shear forces at L4/L5. During pushing and pulling the compression at L4/L5 is from 605 to 1445 N. The extension torque at L4/L5 produced by the push/pull force is counteracted by the forward leaning of the upper body. The shear force is below 202 N in all situations. The torque at the shoulders is between 1 and 38 Nm. In the present experiments the torques at the low back and the shoulders are low during pushing and pulling. No relation exists between the size of the external force and the torque at the low back and the shoulder. Pushing and pulling are common in many workplaces and have often replaced lifting and carrying situations. This has emphasised the need for more knowledge of the internal mechanical load on the body during these activities.

Planoconcave optical microresonator sensors for photoacoustic imaging: pushing the limits of sensitivity (Conference Presentation)

Science.gov (United States)

Guggenheim, James A.; Zhang, Edward Z.; Beard, Paul C.

2016-03-01

Most photoacoustic scanners use piezoelectric detectors but these have two key limitations. Firstly, they are optically opaque, inhibiting backward mode operation. Secondly, it is difficult to achieve adequate detection sensitivity with the small element sizes needed to provide near-omnidirectional response as required for tomographic imaging. Planar Fabry-Perot (FP) ultrasound sensing etalons can overcome both of these limitations and have proved extremely effective for superficial (beam. However, this has the disadvantage that beam walk-off due to the divergence of the beam fundamentally limits the etalon finesse and thus sensitivity - in essence, the problem is one of insufficient optical confinement. To overcome this, novel planoconcave micro-resonator sensors have been fabricated using precision ink-jet printed polymer domes with curvatures matching that of the laser wavefront. By providing near-perfect beam confinement, we show that it is possible to approach the maximum theoretical limit for finesse (f) imposed by the etalon mirror reflectivities (e.g. f=400 for R=99.2% in contrast to a typical planar sensor value of fbeam walk-off, viable sensors can be made with significantly greater thickness than planar FP sensors. This provides an additional sensitivity gain for deep tissue imaging applications such as breast imaging where detection bandwidths in the low MHz can be tolerated. For example, for a 250 μm thick planoconcave sensor with a -3dB bandwidth of 5MHz, the measured NEP was 4 Pa. This NEP is comparable to that provided by mm scale piezoelectric detectors used for breast imaging applications but with more uniform frequency response characteristics and an order-of-magnitude smaller element size. Following previous proof-of-concept work, several important advances towards practical application have been made. A family of sensors with bandwidths ranging from 3MHz to 20MHz have been fabricated and characterised. A novel interrogation scheme based on

"You Hafta Push": Using Sapphire's Novel to Teach Introduction to American Government

Science.gov (United States)

Pappas, Christine

2007-01-01

Using fiction in the classroom can dramatize public policy issues and political science concepts, therefore, making them more real and relevant to students. Sapphire's 1996 novel "Push" puts a face on welfare, rape, incest, child abuse, educational inequalities, homophobia, and AIDS. I also use this novel to discuss the public policy process,…

High-energy neutrino background: Limitations on models of deuterium production

International Nuclear Information System (INIS)

Eichler, D.

1979-01-01

It is pointed out that Epstein's model for deuterium production via high-energy spallation reactions produces high-energy neutrinos in sufficient quantity to stand out above those that are produced by cosmic-ray interactions in the Earth's atmosphere. That the Reines experiment detected neutrinos of atmospheric origin without detecting any cosmic component restricts deuterium production by spallation reactions to very high redshifts (z> or approx. =300). Improved neutrino experiments may be able to push these limits back to recombination

Mind-muscle connection training principle: influence of muscle strength and training experience during a pushing movement.

Science.gov (United States)

Calatayud, Joaquin; Vinstrup, Jonas; Jakobsen, Markus D; Sundstrup, Emil; Colado, Juan Carlos; Andersen, Lars L

2017-07-01

To investigate the effect of different attentional focus conditions on muscle activity during the push-up exercise and to assess the possible influence of muscle strength and training experience. Eighteen resistance-trained men performed 1RM bench press testing and were familiarized with the procedure during the first session. In the second session, three different conditions were randomly performed: regular push-up and push-up focusing on using the pectoralis major and triceps brachii muscles, respectively. Surface electromyography (EMG) was recorded and analyzed (EMG normalized to max; nEMG) for the triceps brachii and pectoralis major muscles. Participants had on average 8 (SD 6) years of training experience and 1RM of 1.25 (SD 0.28) kg per kg bodyweight. Focusing on using pectoralis major increased activity in this muscle by 9% nEMG (95% CI 5-13; Cohen's d 0.60) compared with the regular condition. Triceps activity was not significantly influenced by triceps focus although borderline significant, with a mean difference of 5% nEMG (95% CI 0-10; Cohen's d 0.30). However, years of training experience was positively associated with the ability to selectively activate the triceps (β = 0.41, P = 0.04), but not the pectoralis. Bench press 1RM was not significantly associated with the ability to selectively activate the muscles. Pectoralis activity can be increased when focusing on using this muscle during push-ups, whereas the ability to do this for the triceps is dependent on years of training experience. Maximal muscle strength does not appear to be a decisive factor for the ability to selectively activate these muscles.

Research Note On New Limits of the Coefficient of Gravitation ...

Indian Academy of Sciences (India)

Research Note. On New Limits of the Coefficient of Gravitation Shielding. Michele Caputo. Physics Department, University La Sapienza, Piazzale A. Moro 2, 00185 Roma, Italy. and. Department of Geology and Geophysics, Texas A&M University, College Station TX, 77843,. USA. e-mail: mcaputo@g24ux.phys.uniroma1.it.

The Gamma Factory — new research opportunities for CERN

CERN Multimedia

CERN. Geneva

2017-01-01

In this talk I shall discuss the recent initiative of broadening the present CERN research programme by including a new component exploiting a novel concept of the light source. The proposed, partially stripped ion beam driven, light source is the backbone of the Gamma Factory initiative. It could be realized at CERN by using the infrastructure of the already existing accelerators. It could push the intensity limits of the presently operating light-sources by at least 7 orders of magnitude, reaching the flux of the order of 10^17 photons/s, in the particularly interesting gamma-ray energy domain of 0.1 — 400 MeV. The partially stripped ion beams, the unprecedented-intensity energy-tuned gamma beams, together with the gamma-beam-driven secondary beams of polarized positrons, polarized muons, neutrinos, neutrons and radioactive ions constitute the basic research tools of the Gamma Factory. A broad spectrum of new research opportunities, in a vast domain of uncharted fundamental and applied physics territories...

40 CFR 63.7292 - What work practice standards must I meet for fugitive pushing emissions if I have a by-product...

Science.gov (United States)

2010-07-01

... meet for fugitive pushing emissions if I have a by-product coke oven battery with horizontal flues? 63... meet for fugitive pushing emissions if I have a by-product coke oven battery with horizontal flues? (a...) Prepare and operate by a written plan that will eliminate or minimize incomplete coking for each by...

40 CFR 63.7291 - What work practice standards must I meet for fugitive pushing emissions if I have a by-product...

Science.gov (United States)

2010-07-01

... meet for fugitive pushing emissions if I have a by-product coke oven battery with vertical flues? 63... meet for fugitive pushing emissions if I have a by-product coke oven battery with vertical flues? (a... existing by-product coke oven battery with vertical flues. (1) Observe and record the opacity of fugitive...

Giving the force direction: Analysis of speed skater push off forces with respect to an inertial coordinate system

OpenAIRE

van der Kruk, E.; van der Helm, F.C.T.; Schwab, A.L.; Veeger, H.E.J.

2016-01-01

Pushoff in speed skating requires an extensive motion strategy. During speed skating the skater continuously changes the lean and steering angle of the skate and therewith the direction of push-off, The forces in an inertial coordinate system can give insight into what amount of the push-off force is directed into the forward motion. In this paper we present the preliminary results of a study on the global forces in speed skating. From a mechanical viewpoint, increasing the lean angle of the ...

Generic, Extensible, Configurable Push-Pull Framework for Large-Scale Science Missions

Science.gov (United States)

Foster, Brian M.; Chang, Albert Y.; Freeborn, Dana J.; Crichton, Daniel J.; Woollard, David M.; Mattmann, Chris A.

2011-01-01

different underlying communication middleware (at present, both XMLRPC, and RMI). In addition, the framework is entirely suitable in a multi-mission environment and is supporting both NPP Sounder PEATE and the OCO Mission. Both systems involve tasks such as high-throughput job processing, terabyte-scale data management, and science computing facilities. NPP Sounder PEATE is already using the push-pull framework to accept hundreds of gigabytes of IASI (infrared atmospheric sounding interferometer) data, and is in preparation to accept CRIMS (Cross-track Infrared Microwave Sounding Suite) data. OCO will leverage the framework to download MODIS, CloudSat, and other ancillary data products for use in the high-performance Level 2 Science Algorithm. The National Cancer Institute is also evaluating the framework for use in sharing and disseminating cancer research data through its Early Detection Research Network (EDRN).

Hand forces exerted by long-term care staff when pushing wheelchairs on compliant and non-compliant flooring.

Science.gov (United States)

Lachance, Chantelle C; Korall, Alexandra M B; Russell, Colin M; Feldman, Fabio; Robinovitch, Stephen N; Mackey, Dawn C

2018-09-01

Purpose-designed compliant flooring and carpeting have been promoted as a means for reducing fall-related injuries in high-risk environments, such as long-term care. However, it is not known whether these surfaces influence the forces that long-term care staff exert when pushing residents in wheelchairs. We studied 14 direct-care staff who pushed a loaded wheelchair instrumented with a triaxial load cell to test the effects on hand force of flooring overlay (vinyl versus carpet) and flooring subfloor (concrete versus compliant rubber [brand: SmartCells]). During straight-line pushing, carpet overlay increased initial and sustained hand forces compared to vinyl overlay by 22-49% over a concrete subfloor and by 8-20% over a compliant subfloor. Compliant subflooring increased initial and sustained hand forces compared to concrete subflooring by 18-31% when under a vinyl overlay. In contrast, compliant flooring caused no change in initial or sustained hand forces compared to concrete subflooring when under a carpet overlay. Copyright © 2018 Elsevier Ltd. All rights reserved.

Intrapartum translabial ultrasound with pushing used to predict the difficulty in vacuum-assisted delivery of fetuses in non-occiput posterior position.

Science.gov (United States)

Antonio Sainz, José; Borrero, Carlota; Aquise, Adriana; García-Mejido, José Antonio; Gutierrez, Laura; Fernández-Palacín, Ana

2016-10-01

Our aim is to evaluate the capacity of intrapartum translabial ultrasound (ITU) with pushing in the prediction of difficulty of fetal extraction in vacuum assisted deliveries. Prospective, observational study performed (2/2015-8/2015) on 75 nulliparous women, ≥37 weeks with singleton pregnancies at full dilatation who had ITU-with-pushing performed, previous to vacuum-placement for fetal extraction. Working on the translabial sagittal-plane, we assessed: Angle-Progression (AoP), Progression-Distance (PD) and Head-Direction (HD); in the axial plane we evaluated: Midline-Angle (MLA) and Head-Perineum-Distance (HPD). Vacuum extractions were classified as easy-difficulty (ED) (≤3 vacuum-pulls), difficult-unsuccessful (DD) (>3 vacuum-pulls). We did not assess occipito-posterior-presentations. Seventy nulliparous were studied (44-ED,26-DD). We observed no differences in obstetric, neonatal or intrapartum characteristics between the two study groups, with the following exceptions: newborn weight (3272 ± 438 g versus 3540 ± 372 g; p = 0.011) and number of vacuum-pulls (1.4-ED-vs-4.4-DD; p pushing was 143.9° ± 14.6° in ED and 115.1°± 12.9° in DD (p Pushing was 42.7 ± 11.3 mm versus 30.4 ± 9.8 mm (p Pushing was 27.6°± 26.6° versus 57.5°±26.5°(p=0.025); HPD-Pushing was 40.8 ± 10.0 mm versus 47.4 ± 10.9 mm (p = 0.039). We identified that the presence of an AoP-Pushing > 128° predicts an Easy-Vacuum-Delivery (≤3 Vacuum-Pulls) in  >85% of cases (Sen 80%-FPR 9.3%).

Low-load bench press and push-up induce similar muscle hypertrophy and strength gain.

Science.gov (United States)

Kikuchi, Naoki; Nakazato, Koichi

2017-06-01

To investigate the effect of push-up training with a similar load of to 40% of 1- repetition maximumal (1RM) bench press on muscle hypertrophy and strength gain in men. Eighteen male participants (age, 20.2 ± 0.73 years, range: 19-22 years, height: 169.8 ± 4.4 cm, weight: 64.5 ± 4.7 kg) were randomly assigned to one of two experimental groups: bench press at 40%1RM (bench-press group, n = 9) or push-ups with position adjusted (e.g. kneeling) to the same load of bench-press 40%1RM (push-up group, n = 9), performed twice per week for 8 weeks. Muscle thickness at three sites (biceps, triceps, and pectoralis major), bench-press 1RM, maximum repetition at 40%1RM, and power output (medicine ball throw) were measured before and after the training period. Significant increases in 1RM and muscle thickness (triceps and pectoralis major) were observed in bench-press group (1RM, from 60.0 ± 12.1 kg to 65.0 ± 12.1 kg, p bench-press group (28.4 ± 3.3 mm to 31.5 ± 3.7 mm, p bench press is comparably effective for muscle hypertrophy and strength gain over an 8-week training period.

Pushing the boundaries of cultural congruence pedagogy in science education towards a third space

Science.gov (United States)

Quigley, Cassie

2011-09-01

This review explores Meyers and Crawford's "Teaching science as a cultural way of knowing: Merging authentic inquiry, nature of science, and multicultural strategies" by examining how they combine the use of inquiry-based science instruction with multicultural strategies. In this conversation, I point to the need of specific discourse strategies to help teachers and students create hybrid spaces to push the boundaries of cultural congruence as described in this article. These strategies include a reflective component to the explicit instruction that encourages an integration of home and science discourses. My response to this work expands on their use of multicultural strategies to push toward a congruent Third space that asks not only what happens to the students who do not participate in science, but also what happens to science when a diverse group of people does not participate?

iOS 7 programming pushing the limits

CERN Document Server

Napier, Rob

2014-01-01

Get ready to create killer apps for iPad and iPhone on the new iOS 7! With Apple's introduction of iOS 7, demand for developers who know the new iOS will be high. You need in-depth information about the new characteristics and capabilities of iOS 7, and that's what you'll find in this book. If you have experience with C or C++, this guide will show you how to create amazing apps for iPhone, iPad, and iPod touch. You'll also learn to maximize your programs for mobile devices using iPhone SDK 7.0. Advanced topics such as security services, running on multiple iPlatforms, and local networking w

Outspoken Klenski pushes political limits / Ksenia Repson

Index Scriptorium Estoniae

Repson, Ksenia

2005-01-01

Keskerakonnast välja heidetud Dimitri Klenski soovis kohalikel valimistel osaleda enda loodud valimisliiduga, kuid valimisliitu ei saanud registreerida, kuna selle nimi, "Spissok Klenskogo", oli vastuolus keeleseadusega

Highly Defined Multiblock Copolypeptoids: Pushing the Limits of Living Nucleophilic Ring-Opening Polymerization

KAUST Repository

Fetsch, Corinna

2012-06-05

Advanced macromolecular engineering requires excellent control over the polymerization reaction. Living polymerization methods are notoriously sensitive to impurities, which makes a practical realization of such control very challenging. Reversible-deactivation radical polymerization methods are typically more robust, but have other limitations. Here, we demonstrate by repeated (ge;10 times) chain extension the extraordinary robustness of the living nucleophilic ring-opening polymerization of N-substituted glycine N-carboxyanhydrides, which yields polypeptoids. We observe essentially quantitative end-group fidelity under experimental conditions that are comparatively easily managed. This is employed to synthesize a pentablock quinquiespolymer with high definition. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly Defined Multiblock Copolypeptoids: Pushing the Limits of Living Nucleophilic Ring-Opening Polymerization

KAUST Repository

Fetsch, Corinna; Luxenhofer, Robert

2012-01-01

Advanced macromolecular engineering requires excellent control over the polymerization reaction. Living polymerization methods are notoriously sensitive to impurities, which makes a practical realization of such control very challenging. Reversible-deactivation radical polymerization methods are typically more robust, but have other limitations. Here, we demonstrate by repeated (ge;10 times) chain extension the extraordinary robustness of the living nucleophilic ring-opening polymerization of N-substituted glycine N-carboxyanhydrides, which yields polypeptoids. We observe essentially quantitative end-group fidelity under experimental conditions that are comparatively easily managed. This is employed to synthesize a pentablock quinquiespolymer with high definition. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of klapskate hinge position on push-off performance: a simulation study

NARCIS (Netherlands)

Houdijk, J.H.P.; Bobbert, M.F.; de Koning, J.J.; de Groot, G.

2003-01-01

Purpose: The introduction of the klapskate in speed skating confronts skaters with the question of how to adjust the position of the hinge in order to maximize performance. The purpose of this study was to reveal the constraint that klapskate hinge position imposes on push-off performance in speed

Push versus pull gastrostomy in cancer patients: A single center retrospective analysis of complications and technical success rates.

Science.gov (United States)

Currie, B M; Getrajdman, G I; Covey, A M; Alago, W; Erinjeri, J P; Maybody, M; Boas, F E

2018-04-28

To compare the technical success and complication rates of push versus pull gastrostomy tubes in cancer patients, and to examine their dependence on operator experience. A retrospective review was performed of 304 cancer patients (170 men, 134 women; mean age 60.3±12.6 [SD], range: 19-102 years) referred for primary gastrostomy tube placement, 88 (29%) of whom had a previously unsuccessful attempt at percutaneous endoscopic gastrostomy (PEG) placement. Analyzed variables included method of insertion (push versus pull), indication for gastrostomy, technical success, operator experience, and procedure-related complications within 30 days of placement. Gastrostomy tubes were placed for feeding in 189 patients and palliative decompression in 115 patients. Technical success was 91%: 78% after endoscopy had previously been unsuccessful and 97% when excluding failures associated with prior endoscopy. In the first 30 days, there were 29 minor complications (17.2%) associated with push gastrostomies, and only 8 minor complications (7.5%) with pull gastrostomies (Ptechnical success rates for more versus less experienced operators. Pull gastrostomy tube placement had a lower rate of complications than push gastrostomy tube placement, especially when the indication was decompression. The technical success rate was high, even after a failed attempt at endoscopic placement. Both the rates of success and complications were independent of operator experience. Copyright © 2018 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.

Scientific Research in Education: A Socratic Dialogue

Science.gov (United States)

Boody, Robert M.

2011-01-01

Socrates and Admetus discuss the value of scientific research in education. They conclude that although RCTs have their place, they are not a panacea for education, and that the push for them by NCLB is not warranted.

Inter rater reliability of Pressure Ulcer Scale for Healing (PUSH in patients with chronic leg ulcers Confiabilidad inter-observadores del Pressure Ulcer Scale for Healing (PUSH en pacientes con úlceras crónicas en la pierna Confiabilidade interobservadores do Pressure Ulcer Scale for Healing (PUSH, em pacientes com úlceras crônicas de perna

Directory of Open Access Journals (Sweden)

Vera Lúcia Conceição de Gouveia Santos

2007-06-01

Full Text Available This study aimed to evaluate the inter rater reliability of the Pressure Ulcer Scale for Healing (PUSH, in its version adapted to the Portuguese language, in patients with chronic leg ulcers. Kappa index was used for the analysis. After accomplishing ethical issues, 41 patients with ulcers were examined. A total of 49% of the ulcers were located in the right leg and 36% of them were venous ulcers. The Kappa indices (0.97 to 1.00 obtained in the comparison between the observations of the clinical nurses and the stomal therapists for all sub-scales and for total score, confirmed the tool inter rater reliability, with statistical significance (pEl objetivo del estúdio fue probar la confiabilidad inter-observadores del Pressure Ulcer Scale for Healing (PUSH, en su versión adaptada al portugués, en pacientes con úlceras crónicas en la pierna. Para el análisis de concordancia se utilizó el Indice Kappa. Posterior a la aprobación del Comité de Ética, 41 pacientes con úlcera fueron examinados, siendo que 49% de las úlceras se localizaron a la derecha y 36% eran de etiología venosa. Los indices Kappa obtenidos (0,97 a 1,00, con un nivel significativo de pTestar a confiabilidade interobservadores do Pressure Ulcer Scale for Healing (PUSH, em sua versão adaptada para o português, em pacientes com úlceras crônicas de perna foi o objetivo deste estudo. Para a análise de concordância, utilizou-se o índice Kappa. Após aprovação pelo Comitê de Ética, pacientes com úlceras (41 úlceras foram examinados, sendo que 49% das úlceras localizavam-se à direita e 36% eram de etiologia venosa. Os índices Kappa obtidos (0,97 a 1,00, com significância estatística (p<0,001, ratificaram a confiabilidade interobservadores, ao ser obtida concordância de muito boa a total entre as observações de enfermeiros clínicos e especialistas em estomaterapia (padrão-ouro, para todas as subescalas do PUSH, como para o escore total. Esses resultados

Optimal Design of a Push-Pull-Forward Half-Bridge (PPFHB) Bidirectional DC–DC Converter With Variable Input Voltage

DEFF Research Database (Denmark)

Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high-frequency tr......This paper presents a low-cost bidirectional isolated dc–dc converte, derived from dual-active-bridge converter for the power sources with variable output voltage like supercapacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high...

A centrifuge simulated push-pull manoeuvre with subsequent reduced +Gz tolerance.

Science.gov (United States)

Xu, Yan; Li, Bao-Hui; Zhang, Li-Hui; Jin, Zhao; Wei, Xiao-Yang; Wang, Hong; Wu, San-Yuan; Wang, Hai-Xia; Wang, Quan; Yan, Gui-Ding; Deng, Lue; Geng, Xi-Chen

2012-07-01

The push-pull effect (PPE) has been recognized as a deleterious contributor to fatal flight accidents. The purpose of the study was to establish a push-pull manoeuvre (PPM) simulation with a tri-axes centrifuge, studying the effect of this PPM on the +Gz tolerance, and to make this simulation suitable for pilot centrifuge training. The PPM was realized through pre-programmed acceleration profiles consisting of -1 Gz for 5 s followed by a +Gz plateau for 10 s. Relaxed +Gz tolerance recordings were obtained from 20 healthy male fighter aircraft pilots and 6 healthy male volunteers through exposure to pre-programmed profiles with and without previous -1 Gz exposure. A statistically significant decrease in +Gz tolerance was seen in all subjects after -1 Gz for 5 s exposure, 0.87 ± 0.13 G in the volunteer group and 0.95 ± 0.25 G in the pilot group. The ear opacity pulse as a +Gz tolerance endpoint criterion was sometimes found to be unreliable during the PPM experiments. The simulated PPM in this study elicited a PPE, which was obvious from the significant reduction in +Gz tolerance. The PPM profile appears useful to be included in centrifuge training.

The natural angle between the hand and handle and the effect of handle orientation on wrist radial/ulnar deviation during maximal push exertions.

Science.gov (United States)

Young, Justin G; Lin, Jia-Hua; Chang, Chien-Chi; McGorry, Raymond W

2013-01-01

The purpose of this experiment was to quantify the natural angle between the hand and a handle, and to investigate three design factors: handle rotation, handle tilt and between-handle width on the natural angle as well as resultant wrist radial/ulnar deviation ('RUD') for pushing tasks. Photographs taken of the right upper limb of 31 participants (14 women and 17 men) performing maximal seated push exertions on different handles were analysed. Natural hand/handle angle and RUD were assessed. It was found that all of the three design factors significantly affected natural handle angle and wrist RUD, but participant gender did not. The natural angle between the hand and the cylindrical handle was 65 ± 7°. Wrist deviation was reduced for handles that were rotated 0° (horizontal) and at the narrow width (31 cm). Handles that were tilted forward 15° reduced radial deviation consistently (12-13°) across handle conditions. Manual materials handling (MMH) tasks involving pushing have been related to increased risk of musculoskeletal injury. This study shows that handle orientation influences hand and wrist posture during pushing, and suggests that the design of push handles on carts and other MMH aids can be improved by adjusting their orientation to fit the natural interface between the hand and handle.

High resolution aquifer characterization using crosshole GPR full-waveform tomography: Comparison with direct-push and tracer test data

Science.gov (United States)

Gueting, Nils; Vienken, Thomas; Klotzsche, Anja; van der Kruk, Jan; Vanderborght, Jan; Caers, Jef; Vereecken, Harry; Englert, Andreas

2017-01-01

Limited knowledge about the spatial distribution of aquifer properties typically constrains our ability to predict subsurface flow and transport. Here we investigate the value of using high resolution full-waveform inversion of cross-borehole ground penetrating radar (GPR) data for aquifer characterization. By stitching together GPR tomograms from multiple adjacent crosshole planes, we are able to image, with a decimeter scale resolution, the dielectric permittivity and electrical conductivity of an alluvial aquifer along cross sections of 50 m length and 10 m depth. A logistic regression model is employed to predict the spatial distribution of lithological facies on the basis of the GPR results. Vertical profiles of porosity and hydraulic conductivity from direct-push, flowmeter and grain size data suggest that the GPR predicted facies classification is meaningful with regard to porosity and hydraulic conductivity, even though the distributions of individual facies show some overlap and the absolute hydraulic conductivities from the different methods (direct-push, flowmeter, grain size) differ up to approximately one order of magnitude. Comparison of the GPR predicted facies architecture with tracer test data suggests that the plume splitting observed in a tracer experiment was caused by a hydraulically low-conductive sand layer with a thickness of only a few decimeters. Because this sand layer is identified by GPR full-waveform inversion but not by conventional GPR ray-based inversion we conclude that the improvement in spatial resolution due to full-waveform inversion is crucial to detect small-scale aquifer structures that are highly relevant for solute transport.

Language of Mechanisms: Exam Analysis Reveals Students' Strengths, Strategies, and Errors When Using the Electron-Pushing Formalism (Curved Arrows) in New Reactions

Science.gov (United States)

Flynn, Alison B.; Featherstone, Ryan B.

2017-01-01

This study investigated students' successes, strategies, and common errors in their answers to questions that involved the electron-pushing (curved arrow) formalism (EPF), part of organic chemistry's language. We analyzed students' answers to two question types on midterms and final exams: (1) draw the electron-pushing arrows of a reaction step,…

From the Push of Fear, to the Pull of Hope: Learning by design ...

African Journals Online (AJOL)

From the Push of Fear, to the Pull of Hope: Learning by design. S Sterling. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 License.

Mechanical loading of the low back and shoulders during pushing and pulling activities.

NARCIS (Netherlands)

Hoozemans, M.J.M.; Kingma, I.; Dieen, van J.H.; Vries, de W.K.H.; Woude, van der L.H.V.; Veeger, H.E.J.; Frings-Dresen, M.H.W.; Beek, van der A.J.

2004-01-01

The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the

Mechanical loading of the low back and shoulders during pushing and pulling activities

NARCIS (Netherlands)

Hoozemans, Marco J. M.; Kuijer, P. Paul F. M.; Kingma, Idsart; van Dieën, Jaap H.; de Vries, Wiebe H. K.; van der Woude, Luc H. V.; Veeger, Dirk Jan H. E. J.; van der Beek, Allard J.; Frings-Dresen, Monique H. W.

2004-01-01

The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the

Publishing and Pushing: Mixing Models for Communicating Research Data in Archaeology

Directory of Open Access Journals (Sweden)

Eric C. Kansa

2014-07-01

Full Text Available We present a case study of data integration and reuse involving 12 researchers who published datasets in Open Context, an online data publishing platform, as part of collaborative archaeological research on early domesticated animals in Anatolia. Our discussion reports on how different editorial and collaborative review processes improved data documentation and quality, and created ontology annotations needed for comparative analyses by domain specialists. To prepare data for shared analysis, this project adapted editor-supervised review and revision processes familiar to conventional publishing, as well as more novel models of revision adapted from open source software development of public version control. Preparing the datasets for publication and analysis required significant investment of effort and expertise, including archaeological domain knowledge and familiarity with key ontologies. To organize this work effectively, we emphasized these different models of collaboration at various stages of this data publication and analysis project. Collaboration first centered on data editors working with data contributors, then widened to include other researchers who provided additional peer-review feedback, and finally the widest research community, whose collaboration is facilitated by GitHub’s version control system. We demonstrate that the “publish” and “push” models of data dissemination need not be mutually exclusive; on the contrary, they can play complementary roles in sharing high quality data in support of research. This work highlights the value of combining multiple models in different stages of data dissemination.

Challenges, limits and possibilities of the telejournalism researchers network

Directory of Open Access Journals (Sweden)

Flávio Antônio Camargo Porcello

2011-12-01

Full Text Available This article proposes a theoretical reflection on the challenges, limits and possibilities of network research, with emphasis on the case of the Telejournalism Researchers Network of the Brazilian Association of Journalism Researchers (SBPJor. In addition to a brief historical account of the network´s years of existence, we will deal here with the publications already accomplished, the evolution of the empirical research works, the courses adopted and also the future plans for the amplification, in quantity and quality, of the commitments undertaken. The interaction between theory and practice has always been a basic milestone in the advancement of the group, composed of professors who have had professional activity in television broadcasting stations. TV enters into people´s lives and cannot be seen as a mere support for electronic communication. Telejournalism is an interdisciplinary field which should be studied in its discursive and enunciative aspects. This article will offer some theoretical contributions from authors such as Castells, Bauman, Chauraudeau, Thompson, Gomes and Mattos, among others, to help in shedding light on this path and stimulate the amplification of the theoretical debate proposed.

Comparison of fluoroscopy-guided pull-type percutaneous radiological gastrostomy (pull-type-PRG) with conventional percutaneous radiological gastrostomy (push-type-PRG): clinical results in 253 patients

Energy Technology Data Exchange (ETDEWEB)

Yang, Yang; Schneider, J.; Dueber, C.; Pitton, M.B. [University Medical Center of the Johannes Gutenberg University Mainz, Department of Diagnostic and Interventional Radiology, Mainz (Germany)

2011-11-15

To analyze the clinical results and complications of fluoroscopy guided internal-external pull-type percutaneous radiological gastrostomy (pull-type-PRG) and conventional external-internal percutaneous radiological gastrostomy (push-type-PRG). A total of 253 patients underwent radiological gastrostomy between January 2002 and January 2010. Data were collected retrospectively from radiology reports, Chart review of clinical notes, procedure reports, discharge summaries and subsequent hospital visits. Statistical analysis was performed to compare the two methods for gastrostomy with respect to peri-interventional aspects and clinical results. 128 patients received the Pull-type-PRG whereas the other 125 patients were served with the Push-type-PRG. Indications for gastrostomy were similar in these two groups. The most frequent indications for the both methods were stenotic oesophageal tumors or head/neck tumors (54.7% in pull-type-PRG, 68% in push-type-PRG). Gastrostomy procedures were successful in 98.3% in pull-type-PRG compared to 92% in push-type-PRG. There was no procedure-related mortality. Compared to Push-type-PRG, the peri-interventional complication rate was significantly reduced in pull-type-PRG (14.8% versus 34.4%, P = 0.002). Compared to the external-internal push-type-PRG, the internal-external Pull-type-PRG showed a high primary success rate and a decreased incidence of peri-interventional complications. (orig.)

Comparison of fluoroscopy-guided pull-type percutaneous radiological gastrostomy (pull-type-PRG) with conventional percutaneous radiological gastrostomy (push-type-PRG): clinical results in 253 patients

International Nuclear Information System (INIS)

Yang, Yang; Schneider, J.; Dueber, C.; Pitton, M.B.

2011-01-01

To analyze the clinical results and complications of fluoroscopy guided internal-external pull-type percutaneous radiological gastrostomy (pull-type-PRG) and conventional external-internal percutaneous radiological gastrostomy (push-type-PRG). A total of 253 patients underwent radiological gastrostomy between January 2002 and January 2010. Data were collected retrospectively from radiology reports, Chart review of clinical notes, procedure reports, discharge summaries and subsequent hospital visits. Statistical analysis was performed to compare the two methods for gastrostomy with respect to peri-interventional aspects and clinical results. 128 patients received the Pull-type-PRG whereas the other 125 patients were served with the Push-type-PRG. Indications for gastrostomy were similar in these two groups. The most frequent indications for the both methods were stenotic oesophageal tumors or head/neck tumors (54.7% in pull-type-PRG, 68% in push-type-PRG). Gastrostomy procedures were successful in 98.3% in pull-type-PRG compared to 92% in push-type-PRG. There was no procedure-related mortality. Compared to Push-type-PRG, the peri-interventional complication rate was significantly reduced in pull-type-PRG (14.8% versus 34.4%, P = 0.002). Compared to the external-internal push-type-PRG, the internal-external Pull-type-PRG showed a high primary success rate and a decreased incidence of peri-interventional complications. (orig.)

Superconducting magnet radiation limit considerations for fusion reactors

International Nuclear Information System (INIS)

Sawan, M.E.; Walstrom, P.L.

1986-01-01

The radiation limits for fusion reactor magnets have a direct impact on the cost of electricity. For example, reducing the inboard shield by 1 cm saves up to $3 million in the Tokamak Fusion Core Experiment cost. The magnet components most sensitive to radiation damage are the superconductor, stabilizer, and insulators. Nuclear heating in the magnet affects the design and also impacts the economic performance of the reactor through increased refrigeration costs. The radiation effects in the different components of the magnet are related, as all of them are determined by the flux level in the magnet. Hence, in efforts to push radiation limits, these effects should be considered simultaneously. Furthermore, the levels of radiation effects that correspond to the optimum nuclear heating determined from economic trade-off analysis will be useful in specifying the fluence, dose, and stabilization limit goals for the magnet development program. In this paper, we review the available irradiation data and assess the need for achieving higher irradiation levels

Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers.

Science.gov (United States)

Vohra, Varun; Mróz, Wojciech; Inaba, Shusei; Porzio, William; Giovanella, Umberto; Galeotti, Francesco

2017-08-02

Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm 2 ), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials.

The factor structure of posttraumatic stress disorder: a literature update, critique of methodology, and agenda for future research.

Science.gov (United States)

Elhai, Jon D; Palmieri, Patrick A

2011-08-01

We present an update of recent literature (since 2007) exploring the factor structure of posttraumatic stress disorder (PTSD) symptom measures. Research supporting a four-factor emotional numbing model and a four-factor dysphoria model is presented, with these models fitting better than all other models examined. Variables accounting for factor structure differences are reviewed, including PTSD query instructions, type of PTSD measure, extent of trauma exposure, ethnicity, and timing of administration. Methodological and statistical limitations with recent studies are presented. Finally, a research agenda and recommendations are offered to push this research area forward, including suggestions to validate PTSD’s factors against external measures of psychopathology, test moderators of factor structure, and examine heterogeneity of symptom presentations based on factor structure examination.

Comparison of bond strength of different endodontic sealers to root dentin: An in vitro push-out test.

Science.gov (United States)

Madhuri, G Vijaya; Varri, Sujana; Bolla, Nagesh; Mandava, Pragna; Akkala, Lakshmi Swathi; Shaik, Jaheer

2016-01-01

To compare the bond strength of four different endodontic sealers to root dentin through push-out test design. Forty single-rooted teeth with completely formed apices were selected. Teeth were decoronated, and working length was determined. Instrumentation and irrigation were performed. The teeth were divided into four groups based upon the sealer used. Group 1: Bioceramic sealer (Endosequence), Group 2: Mineral trioxide aggregate (MTA) based sealer (MTA Fill apex), Group 3: Epoxy resin based sealer (MM-Seal), and Group 4: Dual cure resin-based sealer (Hybrid Root Seal). Manipulation and application of the sealer was done as per the manufacturer instructions. All the teeth were obturated using 6% gutta-percha. After obturation, each tooth was prepared for push-out test with root slices of 2 mm thickness using universal testing machine. The highest bond strength was found in Group 1 (Endosequence) (P strength was found in Group 2 (MTA Fill apex). Statistical analysis is done by two-way ANOVA and Newman-Keuls multiple post hoc. The push-out bond strength of Bioceramic sealer was highest followed by resin-based sealer and lowest bond strength was observed in MTA-based sealer.

Voices from the "Working Lives" Project: The Push-Pull of Work and Care

Science.gov (United States)

Fehring, Heather; Herring, Katherine

2012-01-01

A recent policy direction in many OECD countries has been to increase workforce participation for women of childbearing age; a policy direction which seemingly runs counter to a need for improved work-life balance for women themselves. This article explores the impact of this somewhat contradictory "push-pull" of policy by examining some…

A triphenylamine-based push-pull – σ – C60 dyad as photoactive molecular material for single-component organic solar cells: synthesis, characterizations and photophysical properties

KAUST Repository

Labrunie, Antoine; Gorenflot, Julien; Babics, Maxime; Aleveque, Olivier; Dabos-Seignon, Sylvie; Balawi, Ahmed H.; Kan, Zhipeng; Wohlfahrt, Markus; Levillain, Eric; Hudhomme, Pietrick; Beaujuge, Pierre; Laquai, Fré dé ric; Cabanetos, Clé ment; Blanchard, Philippe

2018-01-01

A push-pull – σ – C60 molecular dyad was synthesized via Huisgen-type click-chemistry and used as photoactive material for single-component organic solar cells. Steady-state photoluminescence (PL) experiments of the dyad in solution show a significant quenching of the emission of the push-pull moiety. Spin-casting of a solution of the dyad results in homogenous and smooth thin-films, which exhibit complete PL quenching in line with ultrafast photo-induced electron-transfer in the solid-state. Spectro-electrochemistry reveals the optical signatures of radical cations and radical anions. Evaluation of the charge carrier mobility by space-charge limited current measurements gives an electron-mobility of μe = 4.3 × 10-4 cm2 V-1 s-1, ca. 50 times higher than the hole-mobility. Single-component organic solar cells yield an open-circuit voltage Voc of 0.73 V and a short-circuit current density of 2.1 mA cm-2 however, a poor fill-factor FF (29%) is obtained, resulting in low power conversion efficiency of only 0.4%. Combined TA and time-delayed collection field (TDCF) experiments show mostly ultrafast photon-to-charge conversion and a small component of diffusion-limited exciton dissociation, revealing the presence of pure fullerene domains. Furthermore, a strong field dependence of charge generation is observed, governing the device fill factor, which is further reduced by a competition between extraction and fast recombination of separated charges.

A triphenylamine-based push-pull – σ – C60 dyad as photoactive molecular material for single-component organic solar cells: synthesis, characterizations and photophysical properties

KAUST Repository

Labrunie, Antoine

2018-04-23

A push-pull – σ – C60 molecular dyad was synthesized via Huisgen-type click-chemistry and used as photoactive material for single-component organic solar cells. Steady-state photoluminescence (PL) experiments of the dyad in solution show a significant quenching of the emission of the push-pull moiety. Spin-casting of a solution of the dyad results in homogenous and smooth thin-films, which exhibit complete PL quenching in line with ultrafast photo-induced electron-transfer in the solid-state. Spectro-electrochemistry reveals the optical signatures of radical cations and radical anions. Evaluation of the charge carrier mobility by space-charge limited current measurements gives an electron-mobility of μe = 4.3 × 10-4 cm2 V-1 s-1, ca. 50 times higher than the hole-mobility. Single-component organic solar cells yield an open-circuit voltage Voc of 0.73 V and a short-circuit current density of 2.1 mA cm-2 however, a poor fill-factor FF (29%) is obtained, resulting in low power conversion efficiency of only 0.4%. Combined TA and time-delayed collection field (TDCF) experiments show mostly ultrafast photon-to-charge conversion and a small component of diffusion-limited exciton dissociation, revealing the presence of pure fullerene domains. Furthermore, a strong field dependence of charge generation is observed, governing the device fill factor, which is further reduced by a competition between extraction and fast recombination of separated charges.

Relationship of white matter lesions and severity of pushing behavior after stroke.

Science.gov (United States)

Fujino, Yuji; Amimoto, Kazu; Sugimoto, Satoshi; Fukata, Kazuhiro; Inoue, Masahide; Uchino, Akira; Takahashi, Hidetoshi; Makita, Shigeru

2017-12-01

[Purpose] The relationship between white matter lesions (WMLs) and pushing behavior (PB) is still poorly understood. The purpose of this study was to investigate whether damage from WMLs affects the functional outcome of PB after acute stroke. [Subjects and Methods] In total, 37 patients were included. PB was assessed using the standardized Scale for Contraversive Pushing (SCP). Stroke types were classified as total anterior circulation infarct (TACI), partial anterior circulation infarct (PACI), or lacunar syndrome using the Bamford classification. WML severity was categorized into four groups using the Fazekas visual scale. Thereafter, patients were divided into 4 groups according to the stroke type and/or presence of WMLs. The SCP, Trunk Control Test (TCT), Stroke Impairment Assessment Set (SIAS), and Barthel Index were the outcome measures. [Results] The SCP and TCT in patients with PACI without WMLs were better than those in patients with TACI with or without WMLs. Regarding SCP, TCT, and SIAS, patients with TACI had poorer values compared with PACI, regardless of WML severity. Barthel Index efficiency was not significantly different between the groups. [Conclusion] Our results suggest that moderate to severe WMLs and PACI had a relationship with PB severity and truncal balance.

Laser pushing or pulling of absorbing airborne particles

Energy Technology Data Exchange (ETDEWEB)

Wang, Chuji, E-mail: cw175@msstate.edu; Gong, Zhiyong [Mississippi State University, Starkville, Mississippi 39759 (United States); Pan, Yong-Le; Videen, Gorden [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)

2016-07-04

A single absorbing particle formed by carbon nanotubes in the size range of 10–50 μm is trapped in air by a laser trapping beam and concurrently illuminated by another laser manipulating beam. When the trapping beam is terminated, the movement of the particle controlled by the manipulating beam is investigated. We report our observations of light-controlled pushing and pulling motions. We show that the movement direction has little relationship with the particle size and manipulating beam's parameters but is dominated by the particle's orientation and morphology. With this observation, the controllable optical manipulation is now able to be generalized to arbitrary particles, including irregularly shaped absorbing particles that are shown in this work.

Optical pulling and pushing forces exerted on silicon nanospheres with strong coherent interaction between electric and magnetic resonances.

Science.gov (United States)

Liu, Hongfeng; Panmai, Mingcheng; Peng, Yuanyuan; Lan, Sheng

2017-05-29

We investigated theoretically and numerically the optical pulling and pushing forces acting on silicon (Si) nanospheres (NSs) with strong coherent interaction between electric and magnetic resonances. We examined the optical pulling and pushing forces exerted on Si NSs by two interfering waves and revealed the underlying physical mechanism from the viewpoint of electric- and magnetic-dipole manipulation. As compared with a polystyrene (PS) NS, it was found that the optical pulling force for a Si NS with the same size is enlarged by nearly two orders of magnitude. In addition to the optical pulling force appearing at the long-wavelength side of the magnetic dipole resonance, very large optical pushing force is observed at the magnetic quadrupole resonance. The correlation between the optical pulling/pushing force and the directional scattering characterized by the ratio of the forward to backward scattering was revealed. More interestingly, it was found that the high-order electric and magnetic resonances in large Si NSs play an important role in producing optical pulling force which can be generated by not only s-polarized wave but also p-polarized one. Our finding indicates that the strong coherent interaction between the electric and magnetic resonances existing in nanoparticles with large refractive indices can be exploited to manipulate the optical force acting on them and the correlation between the optical force and the directional scattering can be used as guidance. The engineering and manipulation of optical forces will find potential applications in the trapping, transport and sorting of nanoparticles.

A United States marine presenting with hemoptysis after push-ups.

Science.gov (United States)

Thurber, John S; Unger, Jason A; DeVries, William C

2014-04-01

We present an unusual case of right lower lobe intralobar pulmonary sequestration in a previously healthy and physical active 27-year-old U.S. Marine, who presented with new onset hemoptysis after doing push-ups. Diagnosis was obtained by chest X-ray and contrast computed tomography scan. Preoperatively the patient underwent fluoroscopy-guided embolization of the aberrant systemic artery supplying the sequestration. The segmental resection of the sequestration was then successfully performed through a muscle-sparing thoracotomy. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

AIDA – pushing the boundaries of European particle detector research

CERN Multimedia

Naomi Gilraen Wyles

2011-01-01

AIDA (Advanced European Infrastructures for Detectors at Accelerators), a new project co-funded by the European Union and worth a total of 26 million euros, will be officially launched at CERN next week. The kick-off meeting will take place on 16-18 February, during which Europe-wide detector physicists will come together to begin work on detector infrastructure developments for future particle physics experiments.   Coordinated by CERN, AIDA involves more than 80 institutes and laboratories from 23 countries as beneficiaries or associate partners (the full list can be found here). This four-year project will receive 8 million euros from the European Commission's FP7 Research Infrastructures programme. AIDA will develop facilities covering the four main goals identified by the European Strategy for Particle Physics. These are the LHC upgrade, Linear Colliders, Neutrino facilities and Super-B factories. These facilities will also be available for other researchers in the fields of nuclear and par...

Small-scale field evaluation of push-pull system against early- and outdoor-biting malaria mosquitoes in an area of high pyrethroid resistance in Tanzania [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Arnold S. Mmbando

2017-11-01

Full Text Available Background: Despite high coverage of indoor interventions like insecticide-treated nets, mosquito-borne infections persist, partly because of outdoor-biting, early-biting and insecticide-resistant vectors. Push-pull systems, where mosquitoes are repelled from humans and attracted to nearby lethal targets, may constitute effective complementary interventions. Methods: A partially randomized cross-over design was used to test efficacy of push-pull in four experimental huts and four local houses, in an area with high pyrethroid resistance in Tanzania. The push-pull system consisted of 1.1% or 2.2% w/v transfluthrin repellent dispensers and an outdoor lure-and-kill device (odour-baited mosquito landing box. Matching controls were set up without push-pull. Adult male volunteers collected mosquitoes attempting to bite them outdoors, but collections were also done indoors using exit traps in experimental huts and by volunteers in the local houses. The collections were done hourly (1830hrs-0730hrs and mosquito catches compared between push-pull and controls. An. gambiae s.l. and An. funestus s.l. were assessed by PCR to identify sibling species, and ELISA to detect Plasmodium falciparum and blood meal sources. Results: Push-pull in experimental huts reduced outdoor-biting for An. arabiensis and Mansonia species by 30% and 41.5% respectively. However, the reductions were marginal and insignificant for An. funestus (12.2%; p>0.05 and Culex (5%; p>0.05. Highest protection against all species occurred before 2200hrs. There was no significant difference in number of mosquitoes inside exit traps in huts with or without push-pull. In local households, push-pull significantly reduced indoor and outdoor-biting of An. arabiensis by 48% and 25% respectively, but had no effect on other species. Conclusion: This push-pull system offered modest protection against outdoor-biting An. arabiensis, without increasing indoor mosquito densities. Additional experimentation

The oscillatory behavior of the CoM facilitates mechanical energy balance between push-off and heel strike.

Science.gov (United States)

Kim, Seyoung; Park, Sukyung

2012-01-10

Humans use equal push-off and heel strike work during the double support phase to minimize the mechanical work done on the center of mass (CoM) during the gait. Recently, a step-to-step transition was reported to occur over a period of time greater than that of the double support phase, which brings into question whether the energetic optimality is sensitive to the definition of the step-to-step transition. To answer this question, the ground reaction forces (GRFs) of seven normal human subjects walking at four different speeds (1.1-2.4 m/s) were measured, and the push-off and heel strike work for three differently defined step-to-step transitions were computed based on the force, work, and velocity. To examine the optimality of the work and the impulse data, a hybrid theoretical-empirical analysis is presented using a dynamic walking model that allows finite time for step-to-step transitions and incorporates the effects of gravity within this period. The changes in the work and impulse were examined parametrically across a range of speeds. The results showed that the push-off work on the CoM was well balanced by the heel strike work for all three definitions of the step-to-step transition. The impulse data were well matched by the optimal impulse predictions (R(2)>0.7) that minimized the mechanical work done on the CoM during the gait. The results suggest that the balance of push-off and heel strike energy is a consistent property arising from the overall gait dynamics, which implies an inherited oscillatory behavior of the CoM, possibly by spring-like leg mechanics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Push-off reactions in recovery after tripping discriminate young subjects, older non-fallers and older fallers.

Science.gov (United States)

Pijnappels, Mirjam; Bobbert, Maarten F; van Dieën, Jaap H

2005-06-01

Tripping is a major cause for falls, especially in the elderly. This study investigated whether falls in the elderly can be attributed to inadequate push-off reactions by the support limb in the recovery after a trip. Twelve young (20-34 years) and eleven older (65-72 years) men and women walked over a platform and were tripped several times over an obstacle that suddenly appeared from the floor. Kinematics and ground reactions forces of the support limb during push-off were measured of falls and successful recoveries. Young subjects did not fall. The older subjects were divided into a group of four non-fallers and seven fallers. Older fallers showed insufficient reduction of the angular momentum during push-off and less proper placement of the recovery limb. This was due to a lower rate of change of moment generation in all support limb joints and a lower peak ankle moment. Onset of knee moment generation was slightly delayed in older fallers. Improvement over trials was ascribed to better positioning of the recovery limb, as no clear differences were seen in the joint moments of the support limb. In conclusion, the contribution of the support limb to prevent a fall after tripping is decreased in older adults. Lower limb strength could be an underlying factor and strength training might help to reduce fall risk.

Effect of ultrasonic agitation on push-out bond strength and adaptation of root-end filling materials.

Science.gov (United States)

Alcalde, Murilo Priori; Vivan, Rodrigo Ricci; Marciano, Marina Angélica; Duque, Jussaro Alves; Fernandes, Samuel Lucas; Rosseto, Mariana Bailo; Duarte, Marco Antonio Hungaro

2018-05-01

This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. Sixty maxillary canines were divided into 6 groups ( n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA ( p < 0.05). US improved the push-out bond strength for all the cements ( p < 0.05). The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.

Push-out bond strengths of different dental cements used to cement glass fiber posts.

Science.gov (United States)

Pereira, Jefferson Ricardo; Lins do Valle, Accácio; Ghizoni, Janaina Salomon; Lorenzoni, Fábio César; Ramos, Marcelo Barbosa; Barbosa, Marcelo Ramos; Dos Reis Só, Marcus Vinícius

2013-08-01

Since the introduction of glass fiber posts, irreversible vertical root fractures have become a rare occurrence; however, adhesive failure has become the primary failure mode. The purpose of this study was to evaluate the push-out bond strength of glass fiber posts cemented with different luting agents on 3 segments of the root. Eighty human maxillary canines with similar root lengths were randomly divided into 8 groups (n=10) according to the cement assessed (Rely X luting, Luting and Lining, Ketac Cem, Rely X ARC, Biscem, Duo-link, Rely X U100, and Variolink II). After standardized post space preparation, the root dentin was pretreated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into post spaces with a spiral file and applied to the post surface that was seated into the canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections. The push-out test was performed at a speed of 0.5 mm/min until extrusion of the post occurred. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05). ANOVA showed that the type of interaction between cement and root location significantly influenced the push-out strength (Pcements and glass ionomer cements showed significantly higher values compared to dual-polymerizing resin cements. In all root segments, dual-polymerizing resin cements provided significantly lower bond strength. Significant differences among root segments were found only for Duo-link cement. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Integration of market pull and technology push in the corporate front end and innovation management - Insights from the German software industry

DEFF Research Database (Denmark)

Brem, Alexander; Voigt, K.-I.

2009-01-01

Within the framework of this paper, an extensive literature overview of technology and innovation management aspects on market pull and technology push will be given. The existing classification of market pull and technology push will be particularly shown and called into question by suggesting...... a conceptual framework. Additionally, the most common front end innovation models will be introduced. Finally, the authors will introduce how a technology-based service company is managing the connection of these two alternatives. A special focus will be laid on the accordant methods in order to search...... will be introduced as to how market pull and technology push activities within the corporate technology and innovation management can be integrated. Hence, the purpose of the paper is to introduce a theory-based conceptual framework that can be used in today’s corporate environment. In this context, technology...

Annual research report 1982-1983

International Nuclear Information System (INIS)

1983-01-01

A major rebuilding of the University of Manitoba Spiral Ridge Cyclotron was initiated in 1982-83, beginning conversion to the push-push mode of operation. Research was carried on at other accelerator facilities. Highlights of the year include preparatory work for studies of tensor polarisation in dp breakup; improvements to the neutron beam facility and preliminary studies relevant to a future np radiative capture experiment; the completion of an important part of the (p,n) reaction program involving analogue states of mirror nuclei; studies of the mass-4 system; further studies of recoil polarisation effects in transfer reactions; and the identification of 13 Cs as a unique tumor marker. During the year the Narodny Ion Accelerator was used as an ion implantation device in the study of Raman scattering from implanted materials

Things That Scientists Don't Understand About NASA Spaceflight Research

Science.gov (United States)

Platts, S. H.; Bauer, Terri; Rogers, Shanna

2017-01-01

So you want to conduct human spaceflight research aboard the International Space Station (ISS)? Once your spaceflight research aboard the ISS is proposal is funded.... the real work begins. Because resources are so limited for ISS research, it is necessary to maximize the work being done, while at the same time, minimizing the resources spent. Astronauts may be presented with over 30 human research experiments and select, on average approximately 15 in which to participate. In order to conduct this many studies, ISSMP uses the study requirements provided by the principle investigator to integrate all of this work into the astronauts' complement. The most important thing for investigators to convey to the ISSMP team is their RESEARCH REQUIREMENTS. Requirements are captured in the Experiment document. This document is the official record of how, what, where and when data will be collected. One common mistake that investigators make is not taking this document seriously, but when push comes to shove, if a research requirement is not in this document....it will not get done. The research requirements are then integrated to form a complement of research for each astronaut. What do we mean by integration? Many experiments have overlapping requirements; blood draws, behavioral surveys, heart rate measurement. Where possible, these measures are combined to reduce redundancy and save crew time. Investigators can access these data via data sharing agreements. More examples of how ISS research is integrated will be presented. There are additional limitations commonly associated with human spaceflight research that will also be discussed. Large/heavy hardware, invasive procedures, and toxic reagents are extremely difficult to implement on the ISS. There are strict limits placed on the amount of blood that can be drawn from crew members during (and immediately after) spaceflight. These limits are based on 30-day rolling accumulations. We have recently had to start restricting

The new dedicated PIXE set-up at the National Environmental Research Institute, Denmark

International Nuclear Information System (INIS)

Kemp, Ka ring re; Waahlin, Peter

1999-01-01

The Niels Bohr Institute in Copenhagen was in the beginning of the 70'es one of the early places for PIXE. Contributions were made to the theoretical interpretation of the PIXE spectra as well as the practical application. The home-made 4 MV van de Graaff accelerator at the Niels Bohr Institute was an excellent tool for PIXE. The accelerator, which was used for many years, has now found its place on a museum after more than 40 years of active service. A dedicated PIXE set-up has now been established at the National Environmental Research Institute using a new 1.7 MV Tandem Pelletron (5SDH) from NEC. The main application is elemental analysis of outdoor aerosols. The main work is unsophisticated macro analyses, which do not push the equipment to its limits. This enables automated analysis of about 10,000 samples per year using very limited manpower resources. The research focuses on the contribution from various source types to the atmosphere over Europe, the North Atlantic and Greenland. Source compositions and their temporal variations are studied

LPPS: A Distributed Cache Pushing Based K-Anonymity Location Privacy Preserving Scheme

Directory of Open Access Journals (Sweden)

Ming Chen

2016-01-01

Full Text Available Recent years have witnessed the rapid growth of location-based services (LBSs for mobile social network applications. To enable location-based services, mobile users are required to report their location information to the LBS servers and receive answers of location-based queries. Location privacy leak happens when such servers are compromised, which has been a primary concern for information security. To address this issue, we propose the Location Privacy Preservation Scheme (LPPS based on distributed cache pushing. Unlike existing solutions, LPPS deploys distributed cache proxies to cover users mostly visited locations and proactively push cache content to mobile users, which can reduce the risk of leaking users’ location information. The proposed LPPS includes three major process. First, we propose an algorithm to find the optimal deployment of proxies to cover popular locations. Second, we present cache strategies for location-based queries based on the Markov chain model and propose update and replacement strategies for cache content maintenance. Third, we introduce a privacy protection scheme which is proved to achieve k-anonymity guarantee for location-based services. Extensive experiments illustrate that the proposed LPPS achieves decent service coverage ratio and cache hit ratio with lower communication overhead compared to existing solutions.

Mechanisms of Gait Asymmetry Due to Push-Off Deficiency in Unilateral Amputees.

Science.gov (United States)

Adamczyk, Peter Gabriel; Kuo, Arthur D

2015-09-01

Unilateral lower-limb amputees exhibit asymmetry in many gait features, such as ground force, step time, step length, and joint mechanics. Although these asymmetries result from weak prosthetic-side push-off, there is no proven mechanistic explanation of how that impairment propagates to the rest of the body. We used a simple dynamic walking model to explore possible consequences of a unilateral impairment similar to that of a transtibial amputee. The model compensates for reduced push-off work from one leg by performing more work elsewhere, for example during the middle of stance by either or both legs. The model predicts several gait abnormalities, including slower forward velocity of the body center-of-mass during intact-side stance, greater energy dissipation in the intact side, and more positive work overall. We tested these predictions with data from unilateral transtibial amputees (N = 11) and nonamputee control subjects (N = 10) walking on an instrumented treadmill. We observed several predicted asymmetries, including forward velocity during stance phases and energy dissipation from the two limbs, as well as greater work overall. Secondary adaptations, such as to reduce discomfort, may exacerbate asymmetry, but these simple principles suggest that some asymmetry may be unavoidable in cases of unilateral limb loss.

40 CFR 63.7333 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Science.gov (United States)

2010-07-01

... renewal). (b) For each venturi scrubber applied to pushing emissions and subject to the operating limits... paragraphs (b)(1) through (3) of this section. (1) Maintaining the daily average pressure drop and scrubber... pressure drop and scrubber water flow rate according to § 63.7331(e)(1) through (3). (c) For each hot water...

Colloquium : The future of double β decay research

International Nuclear Information System (INIS)

Zdesenko, Yuri

2002-01-01

The current results and future perspectives of 2β decay research are reviewed. The present status of neutrino physics makes it necessary to enhance the sensitivity of 2β decay experiments (in terms of the half-life limit for the neutrinoless mode) to the level of 10 26 -10 28 yr. Requirements for future supersensitivity projects are formulated and it is concluded that such a goal will certainly be reached in the most realistic next generation experiments (e.g., CAMEO, CUORE, GEM, GENIUS, and MAJORANA), where restrictions on the neutrino mass may be pushed down to m ν ≤0.01-0.05 eV. In addition, the GEM and GENIUS projects may advance the best current limits on the existence of neutralinos--as dark matter candidates--by three orders of magnitude, and at the same time may be able to identify unambiguously the dark matter signal by detection of its seasonal modulation. All of these results will provide crucial tests of the key theoretical models of modern astroparticle physics and cosmology

Implications of dose limit modification for radioactive installations dedicated to research

International Nuclear Information System (INIS)

Lumbreras, J.M.; Fernandez, G.M.; Marana, D.

1992-01-01

The reduced dose limits proposed in the ICRP recommendations affect the Spanish Regulations on Sanitary Protection against Ionizing Radiation. Some implications of this for radioactive installations dedicated to research are pointed out. A very simple statistical study shows that dosimetric data might be used to adopt new criteria for classification of personnel, and even of working areas. (author)

Limitations of demand- and pressure-driven modeling for large deficient networks

Science.gov (United States)

Braun, Mathias; Piller, Olivier; Deuerlein, Jochen; Mortazavi, Iraj

2017-10-01

The calculation of hydraulic state variables for a network is an important task in managing the distribution of potable water. Over the years the mathematical modeling process has been improved by numerous researchers for utilization in new computer applications and the more realistic modeling of water distribution networks. But, in spite of these continuous advances, there are still a number of physical phenomena that may not be tackled correctly by current models. This paper will take a closer look at the two modeling paradigms given by demand- and pressure-driven modeling. The basic equations are introduced and parallels are drawn with the optimization formulations from electrical engineering. These formulations guarantee the existence and uniqueness of the solution. One of the central questions of the French and German research project ResiWater is the investigation of the network resilience in the case of extreme events or disasters. Under such extraordinary conditions where models are pushed beyond their limits, we talk about deficient network models. Examples of deficient networks are given by highly regulated flow, leakage or pipe bursts and cases where pressure falls below the vapor pressure of water. These examples will be presented and analyzed on the solvability and physical correctness of the solution with respect to demand- and pressure-driven models.

New experimental limit on Pauli exclusion principle violation by electrons (VIP experiment)

Energy Technology Data Exchange (ETDEWEB)

Bartalucci, S [NFN, Laboratori Nazionali di Prascati, C.P. 13, Via E. Fermi 40, I-00044, Frascati (Italy); Bertolucci, S [NFN, Laboratori Nazionali di Prascati, C.P. 13, Via E. Fermi 40, I-00044, Frascati (Italy); Bragadireanu, M [NFN, Laboratori Nazionali di Prascati, C.P. 13, Via E. Fermi 40, I-00044, Frascati (Italy)] (and others)

2007-05-15

The Pauli exclusion principle (PEP) represents one of the basic principles of modern physics and, even if there are no compelling reasons to doubt its validity, it still spurs a lively debate, because an intuitive, elementary explanation is still missing, and because of its unique stand among the basic symmetries of physics. A new limit on the probability that PEP is violated by electrons was estabilished by the VIP (Violation of the Pauli exclusion principle) Collaboration, using the method of searching for PEP forbidden atomic transitions in copper. The preliminary value, 1/2{beta}{sup 2} < 4.5 x 10{sup -28}, represents an improvement of about two orders of magnitude of the previous limit. The goal of VIP is to push this limit at the level of 10{sup -30}.

The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study.

Science.gov (United States)

Kao, Huei Chu; Lin, Chiuhsiang Joe; Lee, Yung Hui; Chen, Su Huang

2015-01-01

The purpose of this study was to explore the effects of direction of exertion (DOE) (pushing, pulling), path (walking in a straight line, turning left, walking uphill), and load placement (LP) (the 18 blocks were indicated by X, Y and Z axis; there were 3 levels on the X axis, 2 levels on the Y axis, and 3 levels on the Z axis) on muscle activity and ratings of perceived exertion in nursing cart pushing and pulling tasks. Ten participants who were female students and not experienced nurses were recruited to participate in the experiment. Each participant performed 108 experimental trials in the study, consisting of 2 directions of exertion (push and pull), 3 paths, and 18 load placements (indicated by X, Y and Z axes). A 23kg load was placed into one load placement. The dependent variables were electromyographic (EMG) data of four muscles collected bilaterally as follows: Left (L) and right (R) trapezius (TR), flexor digitorum superficialis (FDS), extensor digitorum (ED), and erector spinae (ES) and subjective ratings of perceived exertion (RPE). Split-split-plot ANOVA was conducted to analyze significant differences between DOE, path, and LP in the EMG and RPE data. Pulling cart tasks produced a significantly higher activation of the muscles (RTR:54.4%, LTR:50.3%, LFDS:57.0%, LED:63.4%, RES:40.7%, LES:36.7%) than pushing cart tasks (RTR:42.4%, LTR:35.1%, LFDS:32.3%, LED:55.1%, RES:33.3%, LES:32.1%). A significantly greater perceived exertion was found in pulling cart tasks than pushing cart tasks. Significantly higher activation of all muscles and perceived exertion were observed for walking uphill than walking in a straight line and turning left. Significantly lower muscle activity of all muscles and subject ratings were observed for the central position on the X axis, the bottom position on the Y axis, and the posterior position on the Z axis. These findings suggest that nursing staff should adopt forward pushing when moving a nursing cart, instead of backward