Ecologically Based Family Therapy Outcome with Substance Abusing Runaway Adolescents

Science.gov (United States)

Slesnick, N.; Prestopnik, J.L.

2005-01-01

Runaway youth report a broader range and higher severity of substance-related, mental health and family problems relative to non-runaway youth. Most studies to date have collected self-report data on the family and social history; virtually no research has examined treatment effectiveness with this population. This study is a treatment development…

Understanding and Preventing Runaway Behavior: Indicators and Strategies for Teachers

Science.gov (United States)

Rafferty, Lisa A.; Raimondi, Sharon

2009-01-01

Runaway behavior is a national epidemic that affects many school-aged youths. Although there are no definitive numbers, it has been estimated that between 1.3 and 2.8 million youths run away each year, and youths with disabilities are more at risk for engaging in runaway behavior than their nondisabled peers. Considering the high number of youths…

Thermal Runaway Severity Reduction Assessment and Implementation: On Li-Ion Batteries

Science.gov (United States)

Darcy, Eric

2015-01-01

Preventing cell-cell thermal runaway propagation and flames/sparks from exiting battery enclosure is possible with proper thermal & electrical design and cell thermal runaway ejecta/effluent management and can be had with minimal mass/volume penalty.

Runaway electrons in toroidal discharges

International Nuclear Information System (INIS)

Knoepfel, H.

1979-01-01

Experimental and theoretical studies of runaway electrons in toroidal devices are reviewed here, with particular reference to tokamaks. The complex phenomenology of runaway effects, which have been the subject of research for the past twenty years, is organized within the framework of a number of physical models. The mechanisms and rates for runaway production are discussed first, followed by sections on runaway-driven kinetic relaxation processes and runaway orbit confinement. Next, the equilibrium and stability of runaway-dominated discharges are reviewed. Models for runaway production at early times in the discharge and the scaling of runaway phenomena to larger devices are also discussed. Finally, detection techniques and possible applications of runaways are mentioned. (author)

Simulation study on avoiding runaway electron generation by magnetic perturbations

International Nuclear Information System (INIS)

Tokuda, S.; Yoshino, R.; Matsumoto, T.; Hudson, S.R.; Kawano, Y.; Takizuka, T.

2001-01-01

Simulations have demonstrated that magnetic islands having the widths expected on the major disruption cause the collisionless loss of the relativistic electrons, and that the resultant loss rate is high enough to avoid or to suppress the runaway generation. It is because, for the magnetic fluctuations in the disruption, the loss of the electron confinement due to the breakdown of the toroidal momentum conservation overwhelms the runaway electron confinement due to the phase-averaging effect of relativistic electrons. Simulation results agree closely with recent experiments on fast plasma shutdown, showing that it is possible to prevent the generation of runaway electrons. (author)

Runaway snakes in TEXTOR-94

International Nuclear Information System (INIS)

Entrop, I.; Jaspers, R.; Lopes Cardozo, N.J.; Finken, K.H.

1999-01-01

Observations of a runaway beam confined in an island-like structure, a so-called runaway snake, are reported. The observations are made in TEXTOR-94 by measurement of synchrotron radiation emitted by these runaways. A full poloidal view allows for the study of the synchrotron pattern of the snake to estimate runaway energy, pitch angle and the radius, shift and safety factor of the drift surface q D at which the runaway beam has developed. The runaway snake parameters are investigated under different current and magnetic field strength conditions. Examples are found of a runaway snake at the q D =1 and the q D =2 drift surface. The radial diffusion coefficient of runaways inside a snake is D r approx. 0.01m 2 s -1 . The rapid runaway losses in regions of (macroscopic) magnetic perturbations outside a snake and the good confinement inside an island assumed to consist of perfect nested surfaces are consistent with magnetic turbulence as the main cause for runaway transport. (author)

Runaway-ripple interaction in Tokamaks

International Nuclear Information System (INIS)

Laurent, L.; Rax, J.M.

1989-08-01

Two approaches of the interaction between runaway electrons and the ripple field, in tokamaks, are discussed. The first approach considers the resonance effect as an intense cyclotron heating of the electrons, by the ripple field, in the guiding center frame of the fast particles. In the second approach, an Hamiltonian formalism is used. A criterion for the onset of chaotic behavior and the results are given. A new universal instability of the runaway population in tokamak configuration is found. When combined with cyclotron losses one of its major consequence is to act as an effective slowing down mechanism preventing the free fall acceleration toward the synchrotron limit. This configuration allows the explanation of some experimental results of Tore Supra and Textor

Runaway electrons and magnetic island confinement

International Nuclear Information System (INIS)

Boozer, Allen H.

2016-01-01

The breakup of magnetic surfaces is a central feature of ITER planning for the avoidance of damage due to runaway electrons. Rapid thermal quenches, which lead to large accelerating voltages, are thought to be due to magnetic surface breakup. Impurity injection to avoid and to mitigate both halo and runaway electron currents utilizes massive gas injection or shattered pellets. The actual deposition is away from the plasma center, and the breakup of magnetic surfaces is thought to spread the effects of the impurities across the plasma cross section. The breakup of magnetic surfaces would prevent runaway electrons from reaching relativistic energies were it not for the persistence of non-intercepting flux tubes. These are tubes of magnetic field lines that do not intercept the walls. In simulations and in magnetic field models, non-intercepting flux tubes are found to persist near the magnetic axis and in the cores of magnetic islands even when a large scale magnetic surface breakup occurs. As long as a few magnetic surfaces reform before all of the non-intercepting flux tubes dissipate, energetic electrons confined and accelerated in these flux tubes can serve as the seed electrons for a transfer of the overall plasma current from thermal to relativistic carriers. The acceleration of electrons is particularly strong because of the sudden changes in the poloidal flux that naturally occur in a rapid magnetic relaxation. The physics of magnetic islands as non-intercepting flux tubes is studied. Expressions are derived for (1) the size of islands required to confine energetic runaway electrons, (2) the accelerating electric field in an island, (3) the increase or reduction in the size of an island by the runaway electron current, (4) the approximate magnitude of the runaway current in an island, and (5) the time scale for the evolution of an island.

Runaway electrons and magnetic island confinement

Energy Technology Data Exchange (ETDEWEB)

Boozer, Allen H., E-mail: ahb17@columbia.edu [Columbia University, New York, New York 10027 (United States)

2016-08-15

The breakup of magnetic surfaces is a central feature of ITER planning for the avoidance of damage due to runaway electrons. Rapid thermal quenches, which lead to large accelerating voltages, are thought to be due to magnetic surface breakup. Impurity injection to avoid and to mitigate both halo and runaway electron currents utilizes massive gas injection or shattered pellets. The actual deposition is away from the plasma center, and the breakup of magnetic surfaces is thought to spread the effects of the impurities across the plasma cross section. The breakup of magnetic surfaces would prevent runaway electrons from reaching relativistic energies were it not for the persistence of non-intercepting flux tubes. These are tubes of magnetic field lines that do not intercept the walls. In simulations and in magnetic field models, non-intercepting flux tubes are found to persist near the magnetic axis and in the cores of magnetic islands even when a large scale magnetic surface breakup occurs. As long as a few magnetic surfaces reform before all of the non-intercepting flux tubes dissipate, energetic electrons confined and accelerated in these flux tubes can serve as the seed electrons for a transfer of the overall plasma current from thermal to relativistic carriers. The acceleration of electrons is particularly strong because of the sudden changes in the poloidal flux that naturally occur in a rapid magnetic relaxation. The physics of magnetic islands as non-intercepting flux tubes is studied. Expressions are derived for (1) the size of islands required to confine energetic runaway electrons, (2) the accelerating electric field in an island, (3) the increase or reduction in the size of an island by the runaway electron current, (4) the approximate magnitude of the runaway current in an island, and (5) the time scale for the evolution of an island.

Electron run-away

International Nuclear Information System (INIS)

Levinson, I.B.

1975-01-01

The run-away effect of electrons for the Coulomb scattering has been studied by Dricer, but the question for other scattering mechanisms is not yet studied. Meanwhile, if the scattering is quasielastic, a general criterion for the run-away may be formulated; in this case the run-away influence on the distribution function may also be studied in somewhat general and qualitative manner. (Auth.)

Dynamics of runaways in JET

International Nuclear Information System (INIS)

Gill, R.D.; Alper, B.; Edwards, A.W.; Ingesson, L.C.; Johnson, M.F.; Ward, D.

2001-01-01

Measurements are presented of the properties of the runaway beams generated in JET following disruptions. Radiation is emitted by the runaways, both when they are in flight and when they hit the vessel walls. Because radiation protected soft x-ray cameras were developed for the JET DT campaign, it has been possible to make the first direct observations of the runaway beam in flight from the x-ray line radiation produced by the beam excitation of K-shell vacancies in the metallic impurities of the residual plasma. These observations give clear images of the runaway beam and provide detailed information on its time development, size, position and stability. The current density and q-profile have also been determined. It has been found that there is a delay between the disruption and the start of runaway generation and this offers a possibility of instigating runaway control methods. Detailed determination of the runaway-wall interaction suggests that the runaways have a braided structure. (author)

Numerical simulation of runaway electron effect on Plasma Facing Components

International Nuclear Information System (INIS)

Ezato, Koichiro; Suzuki, Satoshi; Akiba, Masato; Kunugi, Tomoaki

1998-07-01

The runaway electron effects on Plasma Facing Components (PFCs) are studied by the numerical analyses. The present study is the first investigation of time-dependent thermal response of PFCs caused by runaway electron impact. For this purpose, we developed a new integrated numerical code, which consists of the Monte Carlo code for the coupled electrons and photons transport analysis and the finite element code for the thermo-mechanical analysis. In this code, we apply the practical incident parameters and distribution of runaway electrons recently proposed by S. Putvinski, which can express the time-dependent behavior of runaway electrons impact. The incident parameters of electrons in this study are the energy density ranging from 10 to 75 MJ/m 2 , the average electrons' energy of 12.5 MeV, the incident angle of 0.01deg and the characteristic time constant for decay of runaway electrons event of 0.15sec. The numerical results showed that the divertor with CFC (Carbon-Fiber-Composite) armor did not suffer serious damage. On the other hand, maximum temperatures at the surface of the divertor with tungsten armor and the first wall with beryllium armor exceed the melting point in case of the incident energy density of 20 and 50 MJ/m 2 . Within the range of the incident condition of runaway electrons, the cooling pipe of each PFCs can be prevented from the melting or burn-out caused by runaway electrons impact, which is one of the possible consequences of runaway electrons event so far. (author)

Problems of Maltreated Runaway Youth.

Science.gov (United States)

Kurtz, P. David; And Others

1991-01-01

Shelter staff from 8 states completed Client Information Records on 2,019 runaways. Found significant differences in problems reported by physically abused and sexually abused runaways when compared to nonabused runaway peers. Runaways who were both physically and sexually maltreated were significantly more vulnerable and much worse off than those…

On the inward drift of runaway electrons during the plateau phase of runaway current

Energy Technology Data Exchange (ETDEWEB)

Hu, Di, E-mail: hudi-2@pku.edu.cn [School of Physics, Peking University, Beijing 100871 (China); Qin, Hong [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States); School of Nuclear Science and Technology and Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

2016-03-15

The well observed inward drift of current carrying runaway electrons during runaway plateau phase after disruption is studied by considering the phase space dynamic of runaways in a large aspect ratio toroidal system. We consider the case where the toroidal field is unperturbed and the toroidal symmetry of the system is preserved. The balance between the change in canonical angular momentum and the input of mechanical angular momentum in such a system requires runaways to drift horizontally in configuration space for any given change in momentum space. The dynamic of this drift can be obtained by integrating the modified Euler-Lagrange equation over one bounce time. It is then found that runaway electrons will always drift inward as long as they are decelerating. This drift motion is essentially non-linear, since the current is carried by runaways themselves, and any runaway drift relative to the magnetic axis will cause further displacement of the axis itself. A simplified analytical model is constructed to describe such inward drift both in the ideal wall case and no wall case, and the runaway current center displacement as a function of parallel momentum variation is obtained. The time scale of such displacement is estimated by considering effective radiation drag, which shows reasonable agreement with the observed displacement time scale. This indicates that the phase space dynamic studied here plays a major role in the horizontal displacement of runaway electrons during plateau phase.

Relativistic runaway electrons in tokamak plasmas

International Nuclear Information System (INIS)

Jaspers, R.E.

1995-01-01

Runaway electrons are inherently present in a tokamak, in which an electric field is applied to drive a toroidal current. The experimental work is performed in the tokamak TEXTOR. Here runaway electrons can acquire energies of up to 30 MeV. The runaway electrons are studied by measuring their synchrotron radiation, which is emitted in the infrared wavelength range. The studies presented are unique in the sense that they are the first ones in tokamak research to employ this radiation. Hitherto, studies of runaway electrons revealed information about their loss in the edge of the discharge. The behaviour of confined runaways was still a terra incognita. The measurement of the synchrotron radiation allows a direct observation of the behaviour of runaway electrons in the hot core of the plasma. Information on the energy, the number and the momentum distribution of the runaway electrons is obtained. The production rate of the runaway electrons, their transport and the runaway interaction with plasma waves are studied. (orig./HP)

Runaway electrons during tokamak startup

International Nuclear Information System (INIS)

Sharma, A.S.; Jayakumar, R.

1988-01-01

Runaway electrons significantly affect the plasma and impurity evolution during tokamak startup. During its rise, a runaway pulse stores magnetic flux inductively; this is then released during the decay phase of the runaway pulse. This process affects plasma formation, current initiation and current buildup. Because of their relativistic velocities the runaway electrons have higher ionization and excitation rates than the plasma electrons. This leads to a significant modification of the impurity behaviour and consequently the plasma evolution. (author). 20 refs, 8 figs

Runaway modeling in ORMAK and TNS

International Nuclear Information System (INIS)

Cooper, A.; Swain, D.W.; Marcus, F.B.; Kammash, T.

1977-07-01

A zero-dimensional tokamak start-up code is used to investigate the generation of runaway electrons in the Oak Ridge Tokamak (ORMAK) and The Next Step (TNS) and the effect of the runaways on the plasma breakdown, current, and energy balance, The runaways, which are considered collisionless, are treated self-consistently in the circuit equation by including a runaway current component (determined from a runaway rate equation). During the earliest stages of a discharge, the total current in the plasma is so low that closed flux surfaces do not exist. Runaways produced are lost almost instantly because they follow magnetic field lines that intersect the limiter. Once the current in the tokamak builds up sufficiently, closed flux surfaces start forming which improves runaway containment. The time tau when this occurs is uncertain. Results on ORMAK and TNS are displayed for different values of tau (before which any runaway created is assumed to be lost instantaneously). The assumption of flux surface closure after some arbitrary time tau is then justified by modeling an ORMAK discharge which includes the effects on runaway confinement of error fields generated by currents flowing in the leads to the toroidal field coils. Also shown are ORMAK simulations in different density regimes and TNS results for different loop voltage pulses

Runaway snakes in TEXTOR-94

NARCIS (Netherlands)

Entrop, I.; R. Jaspers,; Cardozo, N. J. L.; Finken, K.H.

1999-01-01

Observations of a runaway beam confined in an island-like structure, a so-called runaway snake, are reported. The observations are made in TEXTOR-94 by measurement of synchrotron radiation emitted by these runaways. A full poloidal View allows for the study of the synchrotron pattern of the snake to

How to prevent runaways in trickle-bed reactors for Pygas hydrogenation

NARCIS (Netherlands)

Westerterp, K.R.; Kronberg, Alexandre E.

2002-01-01

In the past, several runaways have occurred in Trickle-Bed Reactors (TBR) used for the hydrogenation of pyrolysis gasoline as produced in ethylene cracking installations. This phenomenon has been studied in the framework of a special program in the Netherlands, which is administered by the National

Mental Disorders, Comorbidity, and Postrunaway Arrests among Homeless and Runaway Adolescents

Science.gov (United States)

Chen, Xiaojin; Thrane, Lisa; Whitbeck, Les B.; Johnson, Kurt

2006-01-01

This study examined the associations between lifetime mental disorder, comorbidity, and self-reported postrunaway arrests among 428 (187 males, 241 females) homeless and runaway youth. The analysis examined the pattern of arrests across five lifetime mental disorders (alcohol abuse, drug abuse, conduct disorder, major depressive episode, and…

Runaway electron generation in tokamak disruptions

International Nuclear Information System (INIS)

Helander, P.; Andersson, F.; Fueloep, T.; Smith, H.; Anderson, D.; Lisak, M.; Eriksson, L.-G.

2005-01-01

The time evolution of the plasma current during a tokamak disruption is calculated by solving the equations for runaway electron production simultaneously with the induction equation for the toroidal electric field. The resistive diffusion time in a post-disruption plasma is typically comparable to the runaway avalanche growth time. Accordingly, the toroidal electric field induced after the thermal quench of a disruption diffuses radially through the plasma at the same time as it accelerates runaway electrons, which in turn back-react on the electric field. When these processes are accounted for in a self-consistent way, it is found that (1) the efficiency and time scale of runaway generation agrees with JET experiments; (2) the runaway current profile typically becomes more peaked than the pre-disruption current profile; and (3) can easily become radially filamented. It is also shown that higher runaway electron generation is expected if the thermal quench is sufficiently fast. (author)

Runaway electrons in TEXT-U

International Nuclear Information System (INIS)

Freeman, M.R.

1994-01-01

Runaway electrons have long been studied in tokamak plasmas. The previous results regarding runaway electrons and the detection of hard x-rays are reviewed. The hard x-ray energy on TEXT-U is measured and the scaling of energy with electron density, n e , is noted. This scaling suggests a runaway source term that scales roughly as n e / 1 . The results indicate that runaways are created throughout the discharges. An upper bound for X e due to magnetic fluctuations was found to be .0343 m 2 /s. This is an order of magnitude too low to explain the thermal transport in TEXT, implying that electrostatic fluctuations are important in thermal transport in TEXT

Family functioning and mental health in runaway youth: association with posttraumatic stress symptoms.

Science.gov (United States)

Thompson, Sanna J; Cochran, Gerald; Barczyk, Amanda N

2012-10-01

This study examined the direct effects of physical and sexual abuse, neglect, poor family communication and worries concerning family relationships, depression, anxiety, and dissociation on posttraumatic stress symptoms. Runaway youth were recruited from emergency youth shelters in New York and Texas. Interviews were completed with 350 youth who averaged 15 years of age. Structural equation modeling was used to examine family functioning, maltreatment, depression, dissociation, and anxiety in relation to posttraumatic stress symptoms. Results indicated that direct effects of family relationship worry to dissociation, β = .77, p family communication and youth dissociation, β = .42, p stress symptoms, but depression was not. Findings underscore the critical role of family relationships in mental health symptoms experienced by runaway adolescents. Copyright © 2012 International Society for Traumatic Stress Studies.

[Construction of the addiction prevention core competency model for preventing addictive behavior in adolescents].

Science.gov (United States)

Park, Hyun Sook; Jung, Sun Young

2013-12-01

This study was done to provide fundamental data for the development of competency reinforcement programs to prevent addictive behavior in adolescents through the construction and examination of an addiction prevention core competency model. In this study core competencies for preventing addictive behavior in adolescents through competency modeling were identified, and the addiction prevention core competency model was developed. It was validated methodologically. Competencies for preventing addictive behavior in adolescents as defined by the addiction prevention core competency model are as follows: positive self-worth, self-control skill, time management skill, reality perception skill, risk coping skill, and positive communication with parents and with peers or social group. After construction, concurrent cross validation of the addiction prevention core competency model showed that this model was appropriate. The study results indicate that the addiction prevention core competency model for the prevention of addictive behavior in adolescents through competency modeling can be used as a foundation for an integral approach to enhance adolescent is used as an adjective and prevent addictive behavior. This approach can be a school-centered, cost-efficient strategy which not only reduces addictive behavior in adolescents, but also improves the quality of their resources.

The Origin of Runaway Stars

Science.gov (United States)

Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T.

2000-12-01

Milliarcsecond astrometry provided by Hipparcos and by radio observations makes it possible to retrace the orbits of some of the nearest runaway stars and pulsars to determine their site of origin. The orbits of the runaways AE Aurigae and μ Columbae and of the eccentric binary ι Orionis intersected each other ~2.5 Myr ago in the nascent Trapezium cluster, confirming that these runaways were formed in a binary-binary encounter. The path of the runaway star ζ Ophiuchi intersected that of the nearby pulsar PSR J1932+1059, ~1 Myr ago, in the young stellar group Upper Scorpius. We propose that this neutron star is the remnant of a supernova that occurred in a binary system that also contained ζ Oph and deduce that the pulsar received a kick velocity of ~350 km s-1 in the explosion. These two cases provide the first specific kinematic evidence that both mechanisms proposed for the production of runaway stars, the dynamical ejection scenario and the binary-supernova scenario, operate in nature.

Runaway electrons beams in ITER disruptions

International Nuclear Information System (INIS)

Fleischmann, H.H.

1993-01-01

In agreement with the initial projections, the potential generation of runaway beams in disruptions of ITER discharges was performed. This analysis was based on the best-available present projections of plasma parameters existing in large-tokamak disruptions. Using these parameters, the potential contributions from various basic mechanisms for the generation of runway electrons were estimated. The envisioned mechanisms included (i) the well-known Dreicer process (assuming an evaporation of the runways from the thermal distribution), (ii) the seeding of runaway beams resulting from the potential presence of trapped high-temperature electrons from the original discharge still remaining in the disruption plasma at time of reclosure of the magnetic surfaces, and (iii) the generation of runaway beams through avalanche exponentiation of low-level seed runaways resulting via close collisions of existing runaways with cold plasma electrons. Finally, the prospective behavior of the any generated runaway beams -- in particular during their decay -- as well as their potential avoidance and/or damage controlled extraction through the use of magnetic perturbation fields also was considered in some detail

Runaway Children Twelve Years Later: A Follow-Up.

Science.gov (United States)

Olson, Lucy; And Others

1980-01-01

This study was based on intensive interviews with former runaways, nonrunaway siblings, parents, and other relatives. Differences in outcome were found between: (1) runaways and siblings; (2) runaway repeaters and nonrepeaters; and (3) runaways from working-class and middle-class backgrounds. (Author)

High elastic modulus polymer electrolytes suitable for preventing thermal runaway in lithium batteries

Science.gov (United States)

Mullin, Scott; Panday, Ashoutosh; Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

2014-04-22

A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics. In another aspect, the electrolyte exhibits a conductivity drop when the temperature of electrolyte increases over a threshold temperature, thereby providing a shutoff mechanism for preventing thermal runaway in lithium battery cells.

A model for disruption generated runaway electrons

International Nuclear Information System (INIS)

Russo, A.J.; Campbell, R.B.

1993-01-01

One of the possible consequences of disruptions in tokamaks is the generation of runaway electrons which can impact plasma facing components and cause damage, owing to high local energy deposition. This problem becomes more serious as the machine size and plasma current increase. Since large size and high currents are characteristics of proposed future machines, control of runaway generation is an important design consideration. A lumped circuit model for disruption runaway electron generation indicates that impurity concentration and type, as well as plasma motion, can strongly influence runaway behaviour. A comparison of disruption data from several runs on JET and DIII-D with model results demonstrate the effects of impurities, and plasma motion, on runaway number density and energy. The model is also applied to the calculation of runaway currents for ITER. (author). 16 refs, 13 figs

Runaway electron generation as possible trigger for enhancement of magnetohydrodynamic plasma activity and fast changes in runaway beam behavior

International Nuclear Information System (INIS)

Pankratov, I. M.; Zhou, R. J.; Hu, L. Q.

2015-01-01

Peculiar phenomena were observed during experiments with runaway electrons: rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the electron cyclotron emission (ECE) signal (cyclotron radiation of suprathermal electrons). These phenomena were initially observed in TEXTOR (Tokamak Experiment for Technology Oriented Research), where these events only occurred in the current decay phase or in discharges with thin stable runaway beams at a q = 1 drift surface. These rapid changes in the synchrotron spot were interpreted by the TEXTOR team as a fast pitch angle scattering event. Recently, similar rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the non-thermal ECE signal were observed in the EAST (Experimental Advanced Superconducting Tokamak) runaway discharge. Runaway electrons were located around the q = 2 rational magnetic surface (ring-like runaway electron beam). During the EAST runaway discharge, stepwise ECE signal increases coincided with enhanced magnetohydrodynamic (MHD) activity. This behavior was peculiar to this shot. In this paper, we show that these non-thermal ECE step-like jumps were related to the abrupt growth of suprathermal electrons induced by bursting electric fields at reconnection events during this MHD plasma activity. Enhancement of the secondary runaway electron generation also occurred simultaneously. Local changes in the current-density gradient appeared because of local enhancement of the runaway electron generation process. These current-density gradient changes are considered to be a possible trigger for enhancement of the MHD plasma activity and the rapid changes in runaway beam behavior

Runaway electron generation as possible trigger for enhancement of magnetohydrodynamic plasma activity and fast changes in runaway beam behavior

Energy Technology Data Exchange (ETDEWEB)

Pankratov, I. M., E-mail: pankratov@kipt.kharkov.ua, E-mail: rjzhou@ipp.ac.cn [Institute of Plasma Physics, NSC Kharkov Institute of Physics and Technology, Academicheskaya Str. 1, 61108 Kharkov (Ukraine); Zhou, R. J., E-mail: pankratov@kipt.kharkov.ua, E-mail: rjzhou@ipp.ac.cn; Hu, L. Q. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2015-07-15

Peculiar phenomena were observed during experiments with runaway electrons: rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the electron cyclotron emission (ECE) signal (cyclotron radiation of suprathermal electrons). These phenomena were initially observed in TEXTOR (Tokamak Experiment for Technology Oriented Research), where these events only occurred in the current decay phase or in discharges with thin stable runaway beams at a q = 1 drift surface. These rapid changes in the synchrotron spot were interpreted by the TEXTOR team as a fast pitch angle scattering event. Recently, similar rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the non-thermal ECE signal were observed in the EAST (Experimental Advanced Superconducting Tokamak) runaway discharge. Runaway electrons were located around the q = 2 rational magnetic surface (ring-like runaway electron beam). During the EAST runaway discharge, stepwise ECE signal increases coincided with enhanced magnetohydrodynamic (MHD) activity. This behavior was peculiar to this shot. In this paper, we show that these non-thermal ECE step-like jumps were related to the abrupt growth of suprathermal electrons induced by bursting electric fields at reconnection events during this MHD plasma activity. Enhancement of the secondary runaway electron generation also occurred simultaneously. Local changes in the current-density gradient appeared because of local enhancement of the runaway electron generation process. These current-density gradient changes are considered to be a possible trigger for enhancement of the MHD plasma activity and the rapid changes in runaway beam behavior.

Runaway electron generation as possible trigger for enhancement of magnetohydrodynamic plasma activity and fast changes in runaway beam behavior

Science.gov (United States)

Pankratov, I. M.; Zhou, R. J.; Hu, L. Q.

2015-07-01

Peculiar phenomena were observed during experiments with runaway electrons: rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the electron cyclotron emission (ECE) signal (cyclotron radiation of suprathermal electrons). These phenomena were initially observed in TEXTOR (Tokamak Experiment for Technology Oriented Research), where these events only occurred in the current decay phase or in discharges with thin stable runaway beams at a q = 1 drift surface. These rapid changes in the synchrotron spot were interpreted by the TEXTOR team as a fast pitch angle scattering event. Recently, similar rapid changes in the synchrotron spot and its intensity that coincided with stepwise increases in the non-thermal ECE signal were observed in the EAST (Experimental Advanced Superconducting Tokamak) runaway discharge. Runaway electrons were located around the q = 2 rational magnetic surface (ring-like runaway electron beam). During the EAST runaway discharge, stepwise ECE signal increases coincided with enhanced magnetohydrodynamic (MHD) activity. This behavior was peculiar to this shot. In this paper, we show that these non-thermal ECE step-like jumps were related to the abrupt growth of suprathermal electrons induced by bursting electric fields at reconnection events during this MHD plasma activity. Enhancement of the secondary runaway electron generation also occurred simultaneously. Local changes in the current-density gradient appeared because of local enhancement of the runaway electron generation process. These current-density gradient changes are considered to be a possible trigger for enhancement of the MHD plasma activity and the rapid changes in runaway beam behavior.

Inter-machine comparison of the termination phase and energy conversion in tokamak disruptions with runaway current plateau formation and implications for ITER

International Nuclear Information System (INIS)

Martín-Solís, J.R.; Loarte, A.; Hollmann, E.M.; Esposito, B.; Riccardo, V.

2014-01-01

The termination of the current and the loss of runaway electrons following runaway current plateau formation during disruptions have been investigated in the JET, DIII-D and FTU tokamaks. Substantial conversion of magnetic energy into runaway kinetic energy, up to ∼10 times the initial plateau runaway kinetic energy, has been inferred for the slowest current terminations. Both modelling and experiment suggest that, in present devices, the efficiency of conversion into runaway kinetic energy is determined to a great extent by the characteristic runaway loss time, τ diff , and the resistive time of the residual ohmic plasma after the disruption, τ res , increasing with the ratio τ diff /τ res . It is predicted that, in large future devices such as ITER, the generation of runaways by the avalanche mechanism will play an important role, particularly for slow runaway discharge terminations, increasing substantially the amount of energy deposited by the runaways onto the plasma-facing components by the conversion of magnetic energy of the runaway plasma into runaway kinetic energy. Estimates of the power fluxes on the beryllium plasma-facing components during runaway termination in ITER indicate that for runaway currents of up to 2 MA no melting of the components is expected. For larger runaway currents, minimization of the effects of runaway impact on the first wall requires a reduction in the kinetic energy of the runaway beam before termination and, in addition, high plasma density n e and low ohmic plasma resistance (long τ res ) to prevent large conversion of magnetic into runaway kinetic energy during slow current terminations. (paper)

Equilibrium, confinement and stability of runaway electrons in tokamaks

International Nuclear Information System (INIS)

Spong, D.A.

1976-03-01

Some of the ramifications of the runaway population in tokamak experiments are investigated. Consideration is given both to the normal operating regime of tokamaks where only a small fraction of high energy runaways are present and to the strong runaway regime where runaways are thought to carry a significant portion of the toroidal current. In particular, the areas to be examined are the modeling of strong runaway discharges, single particle orbit characteristics of runaways, macroscopic beam-plasma equilibria, and stability against kink modes. A simple one-dimensional, time-dependent model has been constructed in relation to strong runaway discharges. Single particle orbits are analyzed in relation to both the strong runaway regime and the weak regime. The effects of vector E x vector B drifts are first considered in strong runaway discharges and are found to lead to a slow inward shrinkage of the beam. Macroscopic beam-plasma equilibria are treated assuming a pressureless relativistic beam with inertia and using an ideal MHD approximation for the plasma. The stability of a toroidal relativistic beam against kink perturbations is examined using several models

Simulation of tokamak runaway-electron events

International Nuclear Information System (INIS)

Bolt, H.; Miyahara, A.; Miyake, M.; Yamamoto, T.

1987-08-01

High energy runaway-electron events which can occur in tokamaks when the plasma hits the first wall are a critical issue for the materials selection of future devices. Runaway-electron events are simulated with an electron linear accelerator to better understand the observed runaway-electron damage to tokamak first wall materials and to consider the runaway-electron issue in further materials development and selection. The electron linear accelerator produces beam energies of 20 to 30 MeV at an integrated power input of up to 1.3 kW. Graphite, SiC + 2 % AlN, stainless steel, molybdenum and tungsten have been tested as bulk materials. To test the reliability of actively cooled systems under runaway-electron impact layer systems of graphite fixed to metal substrates have been tested. The irradiation resulted in damage to the metal compounds but left graphite and SiC + 2 % AlN without damage. Metal substrates of graphite - metal systems for actively cooled structures suffer severe damage unless thick graphite shielding is provided. (author)

Theoretical and experimental studies of runaway electrons in the TEXTOR tokamak

International Nuclear Information System (INIS)

Abdullaev, S.S.; Finken, K.H.; Wongrach, K.; Willi, O.

2016-01-01

Theoretical and experimental studies of runaway electrons in tokamaks and their mitigations, particularly the recent studies performed by a group of the Heinrich-Heine University Duesseldorf in collaboration with the Institute of Energy and Climate Research of the Research Centre (Forschungszentrum) of Juelich are reviewed. The main topics focus on (i) runaway generation mechanisms, (ii) runaway orbits in equilibrium plasma, (iii) transport in stochastic magnetic fields, (iv) diagnostics and investigations of transport of runaway electron and their losses in low density discharges (v) runaway electrons during plasma disruptions, and (vi) runaway mitigation methods. The development of runaway diagnostics enables the measurement of runaway electrons in both the centre and edge of the plasma. The diagnostics provide an absolute runaway energy resolved measurement, the radial decay length of runaway electrons and, the structure and dynamics of runaway electron beams. The new mechanism of runaway electron formation during plasma disruptions is discussed.

Theoretical and experimental studies of runaway electrons in the TEXTOR tokamak

Energy Technology Data Exchange (ETDEWEB)

Abdullaev, S.S.; Finken, K.H.; Wongrach, K.; Willi, O.

2016-07-01

Theoretical and experimental studies of runaway electrons in tokamaks and their mitigations, particularly the recent studies performed by a group of the Heinrich-Heine University Duesseldorf in collaboration with the Institute of Energy and Climate Research of the Research Centre (Forschungszentrum) of Juelich are reviewed. The main topics focus on (i) runaway generation mechanisms, (ii) runaway orbits in equilibrium plasma, (iii) transport in stochastic magnetic fields, (iv) diagnostics and investigations of transport of runaway electron and their losses in low density discharges (v) runaway electrons during plasma disruptions, and (vi) runaway mitigation methods. The development of runaway diagnostics enables the measurement of runaway electrons in both the centre and edge of the plasma. The diagnostics provide an absolute runaway energy resolved measurement, the radial decay length of runaway electrons and, the structure and dynamics of runaway electron beams. The new mechanism of runaway electron formation during plasma disruptions is discussed.

The Prevalence of Disabilities and Maltreatment among Runaway Children.

Science.gov (United States)

Sullivan, Patricia M.; Knutson, John F.

2000-01-01

Descriptive information was analyzed for maltreated and nonmaltreated runaways from hospital (N=39,352, 255 runaways) and school (N=40,211, 562 runaways) populations. Children and youth with disabilities (especially those with behavior disorders, mental retardation, and communication disorders) were at increased risk to become runaways in both…

Runaway companions of supernova remnants with Gaia

Science.gov (United States)

Boubert, Douglas; Fraser, Morgan; Evans, N. Wyn

2018-04-01

It is expected that most massive stars have companions and thus that some core-collapse supernovae should have a runaway companion. The precise astrometry and photometry provided by Gaia allows for the systematic discovery of these runaway companions. We combine a prior on the properties of runaway stars from binary evolution with data from TGAS and APASS to search for runaway stars within ten nearby supernova remnants. We strongly confirm the existing candidate HD 37424 in S147, propose the Be star BD+50 3188 to be associated with HB 21, and suggest tentative candidates for the Cygnus and Monoceros Loops.

Runaway acceleration during magnetic reconnection in tokamaks

International Nuclear Information System (INIS)

Helander, P; Eriksson, L-G; Andersson, F

2002-01-01

In this paper, the basic theory of runaway electron production is reviewed and recent progress is discussed. The mechanisms of primary and secondary generation of runaway electrons are described and their dynamics during a tokamak disruption is analysed, both in a simple analytical model and through numerical Monte Carlo simulation. A simple criterion for when these mechanisms generate a significant runaway current is derived, and the first self-consistent simulations of the electron kinetics in a tokamak disruption are presented. Radial cross-field diffusion is shown to inhibit runaway avalanches, as indicated in recent experiments on JET and JT-60U. Finally, the physics of relativistic post-disruption runaway electrons is discussed, in particular their slowing down due to emission of synchrotron radiation, and their ability to produce electron-positron pairs in collisions with bulk plasma ions and electrons

Simulation study on dynamics of runaways in tokamaks

International Nuclear Information System (INIS)

Liu Jian; Qin Hong; Fisch, Nathaniel J.

2014-01-01

Electrons with high velocities can be accelerated to very high energies by a strong electric field to form runaway electrons. In tokamak, runaway electrons are produced in many different processes, including the acceleration from the high-energy tail of thermal distribution, through the runaway avalanche, during the rf wave heating and other non-Ohmic current drive, and even in the magnetic reconnection. This proceeding focus on different dynamical problems of runaway electrons in tokamaks. (author)

Study of runaway current generation following disruptions in KSTAR

International Nuclear Information System (INIS)

Chen, Z Y; Kim, W C; Yu, Y W; England, A C; Yoo, J W; Hahn, S H; Yoon, S W; Lee, K D; Oh, Y K; Kwak, J G; Kwon, M

2013-01-01

The high fraction of runaway current conversion following disruptions has an important effect on the first wall for next-generation tokamaks. Because of the potentially severe consequences of a large full current runaway beam on the first wall in an unmitigated disruption, runaway suppression is given a high priority. The behavior of runaway currents both in spontaneous disruptions and in D 2 massive gas injection (MGI) shutdown experiments is investigated in the KSTAR tokamak. The experiments in KSTAR show that the toroidal magnetic field threshold, B T >2 T, for runaway generation is not absolute. A high fraction of runaway current conversion following spontaneous disruptions is observed at a much lower toroidal magnetic field of B T = 1.3 T. A dedicated fast valve for high-pressure gas injection with 39.7 bar is developed for the study of disruptions. A study of runaway current parameters shows that the conversion efficiency of pre-disruptive plasma currents into runaway current can reach over 80% both in spontaneous disruptions and in D 2 MGI shutdown experiments in KSTAR. (paper)

Radial transport of high-energy runaway electrons in ORMAK

International Nuclear Information System (INIS)

Zweben, S.J.; Swain, D.W.; Fleischmann, H.H.

1978-01-01

The transport of high-energy runaway electrons near the outside of a low-density ORMAK discharge is investigated by measuring the flux of runaways to the outer limiter during and after an inward shift of the plasma column. The experimental results are interpreted through a runaway confinement model which includes both the classical outward displacement of the runaway orbit with increasing energy and an additional runaway spatial diffusion coefficient which simulates an unspecified source of anomalous transport. Diffusion coefficients in the range D approximately equal to 10 2 -10 4 cms -1 are found under various discharge conditions indicating a significant non-collisional runaway transport near the outside of the discharge, particularly in the presence of MHD instability. (author)

Disruption generated runaway electrons in TEXTOR and ITER

NARCIS (Netherlands)

R. Jaspers,; Cardozo, N. J. L.; Schüller, F. C.; Finken, K.H.; Grewe, T.; Mank, G.

1996-01-01

Runaway generation during a major disruption has been observed in TEXTOR. Measurements of the synchrotron radiation yielded number, energy and pitch angle of the runaways. A simple model, which assumes that the runaways take over the current density in the centre of the discharge, successfully

Electron runaway in rf discharges

International Nuclear Information System (INIS)

Chen, F.F.

1992-10-01

The critical electric field is computed as a function of pressure and starting energy for electrons to run away to high energies in moderate pressure discharges. The runaway conditions depend critically on the shape of the elastic cross section vs. energy curve. Computations are made for H, H 2 , and He gases, and it is shown that runaway occurs much more readily in atomic hydrogen than in the other gases. The values of the runaway fields are larger than would normally occur in dc discharges, where large voltages would lead to arc formation. However, in rf discharges such electric fields can be sustained over times long compared to electron transit times but short compared to ion transit times. (author)

Digital gaming for HIV prevention with young adolescents.

Science.gov (United States)

Enah, Comfort; Moneyham, Linda; Vance, David E; Childs, Gwendolyn

2013-01-01

The search for intervention strategies appropriate for young adolescents has recently led to the use of digital games. Digital gaming interventions are promising because they may be developmentally appropriate for adolescent populations. The gaming approach also capitalizes on an inherent interest to adolescents and circumvents traditional barriers to access to prevention interventions faced in some geographical areas. Notwithstanding, research on gaming in HIV prevention is quite limited. In this review article, we examine the need for contextually relevant HIV prevention interventions among young adolescents. From this, we provide a theoretical framework for exploring contextually relevant HIV risk factors and a foundation for gathering and using input from the target population to adapt an existing game or to create a developmentally appropriate and contextually relevant HIV prevention game. Copyright © 2013 Association of Nurses in AIDS Care. Published by Elsevier Inc. All rights reserved.

Control of runaway electron energy using externally injected whistler waves

Science.gov (United States)

Guo, Zehua; McDevitt, Christopher J.; Tang, Xian-Zhu

2018-03-01

One way of mitigating runaway damage of the plasma-facing components in a tokamak fusion reactor is by limiting the runaway electron energy under a few MeV, while not necessarily reducing the runaway current appreciably. Here, we describe a physics mechanism by which such momentum space engineering of the runaway distribution can be facilitated by externally injected high-frequency electromagnetic waves such as whistler waves. The drastic impact that wave-induced scattering can have on the runaway energy distribution is fundamentally the result of its ability to control the runaway vortex in the momentum space. The runaway vortex, which is a local circulation of runaways in momentum space, is the outcome of the competition between Coulomb collisions, synchrotron radiation damping, and runaway acceleration by the parallel electric field. By introducing a wave that resonantly interacts with runaways in a particular range of energies which is mildly relativistic, the enhanced scattering would reshape the vortex by cutting off the part that is highly relativistic. The efficiency of resonant scattering accentuates the requirement that the wave amplitude can be small so the power requirement from external wave injection is practical for the mitigation scheme.

Controlling runaway vortex via externally injected high-frequency electromagnetic waves

Science.gov (United States)

Guo, Zehua; McDevitt, Chris; Tang, Xianzhu

2017-10-01

One way of mitigating runaway damage of the plasma-facing components in a tokamak fusion reactor is by limiting the runaway electron energy under a few MeV, while not necessarily reducing the runaway current appreciably. Here we describe a physics mechanism by which such momentum space engineering of the runaway distribution can be facilitated by externally injected high-frequency electromagnetic waves such as the whistler waves. The drastic impact that wave-induced scattering can have on the runaway energy distribution is fundamentally the result of its ability to control the runaway vortex in the momentum space. The runaway vortex, which is a local circulation of runaways in momentum space, is the outcome of the competition between Coulomb collisions, synchrotron radiation damping, and runaway acceleration by parallel electric field. By introducing a wave that resonantly interacts with runaways at a particular range of energy that is mildly relativistic, the enhanced scattering would reshape the vortex by cutting off the part that is highly relativistic. The efficiency of resonant scattering accentuates the requirement that the wave amplitude can be small so the power requirement from external wave injection is practical for the mitigation scheme.

Runaway Children in America: A Review of the Literature.

Science.gov (United States)

Burke, William H.; Burkhead, E. Jane

1989-01-01

The paper reviews the literature regarding runaway children, defines runaway youth, and discusses predisposing factors. Suggestions are offered for further research on the etiology and treatment of runaway behavior. (JDD)

Primary prevention of adolescent pregnancy.

Science.gov (United States)

Schinke, S P; Blythe, B J; Gilchrist, L D; Burt, G A

1981-01-01

Teenage pregnancy is associated with many health, emotional and socioeconomic problems including higher rates of anemia, labor complications, mortality, legal and social struggles and hhigher divorce rates. Professional social workers need strategies to help teenagers avoid early, unwanted pregnancy. This paper offers promising experential and research backing for a primary prevention group work strategy for all adolescents. Social and health programs overlook educational, cognitive anc interpersonal factors biasing youths' ability to comprehend and regulate contraception. Primary prevention to assist adolescents in thinking analytically about their sexual behavior must stress problem solving and decision-making as well as facts about human reproduction and birth control. To implement decisions, youths also need interpersonal communication skills. Small groups are ideal for delivering cognitive-behavioral primary prevention. This approach is based on the premise that youths become pregnant not because of a lack of relevant information, but because they lack cognitive and behavioral skills necessary to use information. Group work involving role-playing helps develop communication skills. Results from 2 field studies describe short-term and longitudinal benefits of the prevention strategy. Professionals can reach significant numbers of youth in this way. By treating sexual issues and the risk of pregnancy as normal in adolescence, social workers can introduce information and pertinent skills to all teenagers. No one is singled out as deviant and the group format enables young people to discuss taboo topics, discovering what the norms are and gradually learning how to deal with peers, family members, techers and others. Adolescents in primary prevention groups gained knowledge, cognitive skills and communication acumen. Improved attitudes toward family planning, increased regular contraception and less unsafe sex resulted from this cognitive-behavioral approach

Runaway electrons in disruptions and perturbed magnetic topologies of tokamak plasmas

International Nuclear Information System (INIS)

Forster, Michael

2012-01-01

Nuclear fusion represents a valuable perspective for a safe and reliable energy supply from the middle of the 21st century on. Currently, the tokamak is the most advanced principle of confining a man-made fusion plasma. The operation of future, reactor sized tokamaks like ITER faces a crucial difficulty in the generation of runaway electrons. The runaway of electrons is a free fall acceleration into the relativistic regime which is known in various kinds of plasmas including astrophysical ones, thunderbolts and fusion plasmas. The tokamak disruption instability can include the conversion of a substantial part of the plasma current into a runaway electron current. When the high energetic runaways are lost, they can strike the plasma facing components at localised spots. Due to their high energies up to a few tens of MeV, the runaways carry the potential to reduce the lifetimes of wall components and even to destroy sensitive, i.e. actively cooled parts. The research for effective ways to suppress the generation of runaway electrons is hampered by the lack of a complete understanding of the physics of the runaways in disruptions. As it is practically impossible to use standard electron detectors in the challenging environment of a tokamak, the experimental knowledge about runaways is limited and it relies on rather indirect techniques of measurement. The main diagnostics used for this PhD work are three reciprocating probes which measure the runaway electrons directly at the plasma edge of the tokamak TEXTOR. A calorimetric probe and a material probe which exploits the signature that a runaway beam impact leaves in the probe were developed in the course of the PhD work. Novel observations of the burst-like runaway electron losses in tokamak disruptions are reported. The runaway bursts are temporally resolved and first-time measurements of the corresponding runaway energy spectra are presented. A characteristic shape and typical burst to burst variations of the

On the avalanche generation of runaway electrons during tokamak disruptions

International Nuclear Information System (INIS)

Martín-Solís, J. R.; Loarte, A.; Lehnen, M.

2015-01-01

A simple zero dimensional model for a tokamak disruption is developed to evaluate the avalanche multiplication of a runaway primary seed during the current quench phase of a fast disruptive event. Analytical expressions for the plateau runaway current, the energy of the runaway beam, and the runaway energy distribution function are obtained allowing the identification of the parameters dominating the formation of the runaway current during disruptions. The effect of the electromagnetic coupling to the vessel and the penetration of the external magnetic energy during the disruption current quench as well as of the collisional dissipation of the runaway current at high densities are investigated. Current profile shape effects during the formation of the runaway beam are also addressed by means of an upgraded one-dimensional model

Diffusion with Varying Drag; the Runaway Problem.

Science.gov (United States)

Rollins, David Kenneth

We study the motion of electrons in an ionized plasma of electrons and ions in an external electric field. A probability distribution function describes the electron motion and is a solution of a Fokker-Planck equation. In zero field, the solution approaches an equilibrium Maxwellian. For arbitrarily small field, electrons overcome the diffusive effects and are freely accelerated by the field. This is the electron runaway phenomenon. We treat the electric field as a small perturbation. We consider various diffusion coefficients for the one dimensional problem and determine the runaway current as a function of the field strength. Diffusion coefficients, non-zero on a finite interval are examined. Some non-trivial cases of these can be solved exactly in terms of known special functions. The more realistic case where the diffusion coefficient decays with velocity are then considered. To determine the runaway current, the equivalent Schrodinger eigenvalue problem is analysed. The smallest eigenvalue is shown to be equal to the runaway current. Using asymptotic matching a solution can be constructed which is then used to evaluate the runaway current. The runaway current is exponentially small as a function of field strength. This method is used to extract results from the three dimensional problem.

Diffusion with varying drag; the runaway problem

International Nuclear Information System (INIS)

Rollins, D.K.

1986-01-01

The motion of electrons in an ionized plasma of electrons and ions in an external electric field is studied. A probability distribution function describes the electron motion and is a solution of a Fokker-Planck equation. In zero field, the solution approaches an equilibrium Maxwellian. For arbitrarily small field, electrons overcome the diffusive effects and are freely accelerated by the field. This is the electron-runaway phenomenon. The electric field is treated as a small perturbation. Various diffusion coefficients are considered for the one dimensional problem, and the runaway current is determined as a function of the field strength. Diffusion coefficients, non-zero on a finite interval are examined. Some non-trivial cases of these can be solved exactly in terms of known special functions. The more realistic case where the diffusion coeffient decays with velocity are then considered. To determine the runaway current, the equivalent Schroedinger eigenvalue problem is analyzed. The smallest eigenvalue is shown to be equal to the runaway current. Using asymptotic matching, a solution can be constructed which is then used to evaluate the runaway current. The runaway current is exponentially small as a function of field strength. This method is used to extract results from the three dimensional problem

Characteristics of post-disruption runaway electrons with impurity pellet injection

International Nuclear Information System (INIS)

Kawano, Yasunori; Nakano, Tomohide; Isayama, Akihiko; Asakura, Nobuyuki; Tamai, Hiroshi; Kubo, Hirotaka; Takenaga, Hidenobu; Bakhtiari, Mohammad; Ide, Shunsuke; Kondoh, Takashi; Hatae, Takaki

2005-01-01

Characteristics of post-disruption runaway electrons with impurity pellet injection were investigated for the first time using the JT-60U tokamak device. A clear deposition of impurity neon ice pellets was observed in a post-disruption runaway plasma. The pellet ablation was attributed to the energy deposition of relativistic runaway electrons in the pellet. A high normalized electron density was stably obtained with n e bar /n GW ∼2.2. Effects of prompt exhaust of runaway electrons and reduction of runaway plasma current without large amplitude MHD activities were found. One possible explanation for the basic behavior of runaway plasma current is that it follows the balance of avalanche generation of runaway electrons and slowing down predicted by the Andersson-Helander model, including the combined effect of collisional pitch angle scattering and synchrotron radiation. Our results suggested that the impurity pellet injection reduced the energy of runaway electrons in a stepwise manner. (author)

[Effectiveness of institutional policies to prevent adolescent alcohol use: The view of experts and adolescents].

Science.gov (United States)

Suárez, Cristian; del Moral, Gonzalo; Musitu, Gonzalo; Sánchez, Juan Carlos; John, Bev

2014-01-01

The objective of this study is to obtain the views of a sample of adolescents and experts on adolescence, family, school, local policies and media, regarding the effectiveness of institutional policies to prevent adolescent alcohol use. Four educational centers in the province of Seville. Head office of the Alcohol and Society Foundation in Madrid. Qualitative study using the method proposed by Grounded theory (Glaser and Strauss, 1967). Data were collected from 10 discussion groups guided by semistructured interviews. The data were analyzed using Atlas ti 5 software. A total of 32 national experts and 40 adolescents of both sexes aged 15 to 20 years living in the province of Seville, selected by theoretical intentional sampling. The experts believed that most of the evaluated preventive actions were effective, while adolescents disputed the preventive impact of most of them. Adolescents proposed actions focused on the reduction of supply of alcohol. Experts proposed a mixed model as the most effective strategy to prevent alcohol consumption in adolescents, combining supply and demand reduction policies, depending on specific short and long term objectives. We have obtained, not only an overview of what is working (or not) from the view of adolescents and experts, but also the key points that should be taken into account for designing effective prevention policies. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

Anomalous resistivity due to low-frequency turbulence. [of collisionless plasma with limited acceleration of high velocity runaway electrons

Science.gov (United States)

Rowland, H. L.; Palmadesso, P. J.

1983-01-01

Large amplitude ion cyclotron waves have been observed on auroral field lines. In the presence of an electric field parallel to the ambient magnetic field these waves prevent the acceleration of the bulk of the plasma electrons leading to the formation of a runaway tail. It is shown that low-frequency turbulence can also limit the acceleration of high-velocity runaway electrons via pitch angle scattering at the anomalous Doppler resonance.

The prevention of teenage pregnancy in adolescent's view

OpenAIRE

Fiedler, Milla Wildemberg; Araújo, Alisson; Souza, Márcia Christina Caetano de

2015-01-01

The objective of the research is to understand the vision of adolescents on the prevention of adolescent pregnancy in a school in the municipality of Divinópolis, Minas Gerais. This is a descriptive study, exploratory, with a qualitative approach, with 14 adolescents. Semistructured interviews. Data were analyzed and interpreted by discourse analysis. The analysis of the reports of the subjects interviewed originated four empirical categories: perception about the importance of preventing tee...

[Violence prevention in childhood and adolescence--a brief overview].

Science.gov (United States)

Pawils, Silke; Metzner, Franka

2016-01-01

Aggressive and violent behaviour in children and adolescents can be associated with physical and psychological health effects continuing into adulthood. Early programs for violence prevention in childhood and adolescence are intended to prevent or reduce aggressive behaviour in order to decrease the risk for short- and long-term developmental impairments. In a literature review, research findings on prevalence, typical courses of development, and predictors of violent behavior in childhood are first summarized and compared with findings on the frequency, developmental course, and consequences of youth violence. International and German programs for violence prevention in children and adolescents are presented in the context of various settings (family, school, community), target groups (primary vs. secondary prevention) as well as target variables (universal vs. specific). Empirical findings on efficacy testing of violence prevention programs are described and discussed. The presented findings stress the relevance and potential of services for violence prevention for children and adolescents, but also demonstrate the challenges and gaps.

Runaway electron transport studies in the HL-1M tokamak

International Nuclear Information System (INIS)

Zheng Yongzhen; Qi Changwei; Ding Xuantong; Li Wenzhong

2002-01-01

The transport of runaway electrons in a hot plasma has been studied in four experiments, which provide the runaway diffusivity D r The first experiment obtained runaway electrons using a steady state approach for values of the runaway confinement time τ r , deduced from hard X-ray bremsstrahlung spectra. In the second experiment, diffusion has been interpreted in terms of the magnetic fluctuation, from which a electron thermal diffusivity can be deduced. Runaway electro diffusion coefficient is determined by intrinsic magnetic fluctuations, rather than electrostatic fluctuations because of the high energy involved. The results presented here demonstrate the efficiency of using runaway transport techniques for determining intrinsic magnetic fluctuations

Localized thermonuclear runaways and volcanoes on degenerate dwarf stars

Energy Technology Data Exchange (ETDEWEB)

Shara, M.M.

1982-10-15

Practically all studies to date of thermonuclear runaways on degenerate dwarf stars in binary systems have considered only spherically symmetric eruptions. We emphasize that even slightly non-spherically symmetric accretion leads to transverse temperature gradients in the dwarfs' accreted envelopes. Over a rather broad range of parameter space, thermalization time scales in accreted envelopes are much longer than thermonuclear runaway time scales. Thus localized thermonuclear runaways (i.e., runaways much smaller than the host degenerate star) rather than spherically symmetric global eruptions are likely to occur on many degenerate dwarfs. Localized runaways are more likely to occur on more massive and/or hotter dwarfs.

Worldwide application of prevention science in adolescent health

Science.gov (United States)

Catalano, Richard F; Fagan, Abigail A; Gavin, Loretta E; Greenberg, Mark T; Irwin, Charles E; Ross, David A; Shek, Daniel T L

2015-01-01

The burden of morbidity and mortality from non-communicable disease has risen worldwide and is accelerating in low-income and middle-income countries, whereas the burden from infectious diseases has declined. Since this transition, the prevention of non-communicable disease as well as communicable disease causes of adolescent mortality has risen in importance. Problem behaviours that increase the short-term or long-term likelihood of morbidity and mortality, including alcohol, tobacco, and other drug misuse, mental health problems, unsafe sex, risky and unsafe driving, and violence are largely preventable. In the past 30 years new discoveries have led to prevention science being established as a discipline designed to mitigate these problem behaviours. Longitudinal studies have provided an understanding of risk and protective factors across the life course for many of these problem behaviours. Risks cluster across development to produce early accumulation of risk in childhood and more pervasive risk in adolescence. This understanding has led to the construction of developmentally appropriate prevention policies and programmes that have shown short-term and long-term reductions in these adolescent problem behaviours. We describe the principles of prevention science, provide examples of efficacious preventive interventions, describe challenges and potential solutions to take efficacious prevention policies and programmes to scale, and conclude with recommendations to reduce the burden of adolescent mortality and morbidity worldwide through preventive intervention. PMID:22538180

MHD stability of runaway electron discharge in tokamaks

International Nuclear Information System (INIS)

Wakatani, M.

1978-04-01

A runaway current concentrating in the central region has stabilizing effects on kink and tearing instabilities on the basis of a model in which the runaway current is assumed rigid. The Kruskal-Shafranov limit (iota(a) = iota sub(σ(a) + iota sub( b)(a) <= 1) disappears for iota sub(σ(a) <= 0.2 in the case of parabolic profiles of both the runaway current and the conduction current. Here iota sub(σ)(a) is a rotational transform due to the conduction current and iota sub( b)(a) is a rotational transform due to the runaway current. (auth.)

Kinetic modelling of runaway electron avalanches in tokamak plasmas

International Nuclear Information System (INIS)

Nilsson, E; Peysson, Y; Saint-Laurent, F; Decker, J; Granetz, R S; Vlainic, M

2015-01-01

Runaway electrons can be generated in tokamak plasmas if the accelerating force from the toroidal electric field exceeds the collisional drag force owing to Coulomb collisions with the background plasma. In ITER, disruptions are expected to generate runaway electrons mainly through knock-on collisions (Hender et al 2007 Nucl. Fusion 47 S128–202), where enough momentum can be transferred from existing runaways to slow electrons to transport the latter beyond a critical momentum, setting off an avalanche of runaway electrons. Since knock-on runaways are usually scattered off with a significant perpendicular component of the momentum with respect to the local magnetic field direction, these particles are highly magnetized. Consequently, the momentum dynamics require a full 3D kinetic description, since these electrons are highly sensitive to the magnetic non-uniformity of a toroidal configuration. For this purpose, a bounce-averaged knock-on source term is derived. The generation of runaway electrons from the combined effect of Dreicer mechanism and knock-on collision process is studied with the code LUKE, a solver of the 3D linearized bounce-averaged relativistic electron Fokker–Planck equation (Decker and Peysson 2004 DKE: a fast numerical solver for the 3D drift kinetic equation Report EUR-CEA-FC-1736, Euratom-CEA), through the calculation of the response of the electron distribution function to a constant parallel electric field. The model, which has been successfully benchmarked against the standard Dreicer runaway theory now describes the runaway generation by knock-on collisions as proposed by Rosenbluth (Rosenbluth and Putvinski 1997 Nucl. Fusion 37 1355–62). This paper shows that the avalanche effect can be important even in non-disruptive scenarios. Runaway formation through knock-on collisions is found to be strongly reduced when taking place off the magnetic axis, since trapped electrons can not contribute to the runaway electron population. Finally

Alfvénic instabilities driven by runaways in fusion plasmas

International Nuclear Information System (INIS)

Fülöp, T.; Newton, S.

2014-01-01

Runaway particles can be produced in plasmas with large electric fields. Here, we address the possibility that such runaway ions and electrons excite Alfvénic instabilities. The magnetic perturbation induced by these modes can enhance the loss of runaways. This may have important implications for the runaway electron beam formation in tokamak disruptions

Modelling Venting and Pressure Build-up in a 18650 LCO Cell during Thermal Runaway (ABSTRACT)

DEFF Research Database (Denmark)

Coman, Paul Tiberiu; Veje, Christian; White, Ralph

Li-ion batteries are a very popular type of electric storage devices that possess high energy density when compared to the other battery chemistries. Due to this property, when operating under abusive conditions such as high ambient temperature, the batteries can experience thermal runaway, which...... may lead to fires and explosions. To prevent this, it is therefore important to model thermal runaway considering different events such as venting and the pressure development inside the battery cell, which makes the main purpose of this paper. A model consisting of the different decomposition....... By fitting the activation energies, and measuring experimentally the mass of the ejecta during thermal runaway, the model is compared and validated against an extensive experiment performed by Golukbov et al. [1] during oven heating. When analysing the results, it is found that by including the venting...

Observation of runaway electrons by infrared camera in J-TEXT

Energy Technology Data Exchange (ETDEWEB)

Tong, R. H.; Chen, Z. Y., E-mail: zychen@hust.edu.cn; Zhang, M.; Huang, D. W.; Yan, W.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2016-11-15

When the energy of confined runaway electrons approaches several tens of MeV, the runaway electrons can emit synchrotron radiation in the range of infrared wavelength. An infrared camera working in the wavelength of 3-5 μm has been developed to study the runaway electrons in the Joint Texas Experimental Tokamak (J-TEXT). The camera is located in the equatorial plane looking tangentially into the direction of electron approach. The runaway electron beam inside the plasma has been observed at the flattop phase. With a fast acquisition of the camera, the behavior of runaway electron beam has been observed directly during the runaway current plateau following the massive gas injection triggered disruptions.

On the kinematics of a runaway Be star population

Science.gov (United States)

Boubert, D.; Evans, N. W.

2018-04-01

We explore the hypothesis that B type emission-line stars (Be stars) have their origin in mass-transfer binaries by measuring the fraction of runaway Be stars. We assemble the largest-to-date catalogue of 632 Be stars with 6D kinematics, exploiting the precise astrometry of the Tycho-Gaia Astrometric Solution (TGAS) from the first Gaia Data Release. Using binary stellar evolution simulations, we make predictions for the runaway and equatorial rotation velocities of a runaway Be star population. Accounting for observational biases, we calculate that if all classical Be stars originated through mass transfer in binaries, then 17.5% of the Be stars in our catalogue should be runaways. The remaining 82.5% should be in binaries with subdwarfs, white dwarfs or neutron stars, because those systems either remained bound post-supernova or avoided the supernova entirely. Using a Bayesian methodology, we compare the hypothesis that each Be star in our catalogue is a runaway to the null hypothesis that it is a member of the Milky Way disc. We find that 13.1^{+2.6}_{-2.4}% of the Be stars in our catalogue are runaways, and identify a subset of 40 high-probability runaways. We argue that deficiencies in our understanding of binary stellar evolution, as well as the degeneracy between velocity dispersion and number of runaway stars, can explain the slightly lower runaway fraction. We thus conclude that all Be stars could be explained by an origin in mass-transfer binaries. This conclusion is testable with the second Gaia data release (DR2).

Transport of runaway and thermal electrons due to magnetic microturbulence

International Nuclear Information System (INIS)

Mynick, H.E.; Strachan, J.D.

1981-01-01

The ratio of the runaway electron confinement to thermal electron energy confinement is derived for tokamaks where both processes are determined by free streaming along stochastic magnetic field lines. The runaway electron confinement is enhanced at high runaway electron energies due to phase averaging over the magnetic perturbations when the runaway electron drift surfaces are displaced from the magnetic surfaces. Comparison with experimental data from LT-3, Ormak, PLT, ST, and TM-3 indicates that magnetic stochasticity may explain the relative transport rates of runaways and thermal electron energy

Collisional avalanche exponentiation of runaway electrons in electrified plasmas

International Nuclear Information System (INIS)

Jayakumar, R.; Fleischmann, H.H.; Zweben, S.J.

1993-01-01

In contrast to earlier expectations, it is estimated that generation of runaway electrons from close collisions of existing runaways with cold plasma electrons can be significant even for small electric fields, whenever runaways can gain energies of about 20 MeV or more. In that case, the runaway population will grow exponentially with the energy spectrum showing an exponential decrease towards higher energies. Energy gains of the required magnitude may occur in large tokamak devices as well as in cosmic-ray generation. (orig.)

Native Teen Voices: adolescent pregnancy prevention recommendations.

Science.gov (United States)

Garwick, Ann W; Rhodes, Kristine L; Peterson-Hickey, Melanie; Hellerstedt, Wendy L

2008-01-01

American Indian adolescent pregnancy rates are high, yet little is known about how Native youth view primary pregnancy prevention. The aim was to identify pregnancy prevention strategies from the perspectives of both male and female urban Native youth to inform program development. Native Teen Voices (NTV) was a community-based participatory action research study in Minneapolis and St. Paul, Minnesota. Twenty focus groups were held with 148 Native youth who had never been involved in a pregnancy. Groups were stratified by age (13-15 and 16-18 years) and sex. Participants were asked what they would do to prevent adolescent pregnancy if they were in charge of programs for Native youth. Content analyses were used to identify and categorize the range and types of participants' recommendations within and across the age and sex cohorts. Participants in all cohorts emphasized the following themes: show the consequences of adolescent pregnancy; enhance and develop more pregnancy prevention programs for Native youth in schools and community-based organizations; improve access to contraceptives; discuss teen pregnancy with Native youth; and use key messages and media to reach Native youth. Native youth perceived limited access to comprehensive pregnancy prevention education, community-based programs and contraceptives. They suggested a variety of venues and mechanisms to address gaps in sexual health services and emphasized enhancing school-based resources and involving knowledgeable Native peers and elders in school and community-based adolescent pregnancy prevention initiatives. A few recommendations varied by age and sex, consistent with differences in cognitive and emotional development.

Scaling law of runaway electrons in the HL-1M tokamak

International Nuclear Information System (INIS)

Zheng Yongzhen

2005-01-01

Runaway confinement time in ohmic and additionally heated tokamak plasmas presents an anomalous behavior in comparison with theoretical predictions based on neoclassical models. A one-dimensional numerical including generation and loss effects for runaway electrons is used to deduce the dependence of runaway energy ε τ on runaway confinement time. The simulation results are presented in the form of a scaling law for ε τ on plasma parameters. The scaling of ε τ and therefore the runaway confinement time and runaway electron diffusivity has been studied in the HL-1M tokamak, by measuring hard X-ray spectra under different experimental conditions. (authors)

Mitigating Thermal Runaway Risk in Lithium Ion Batteries

Science.gov (United States)

Darcy, Eric; Jeevarajan, Judy; Russell, Samuel

2014-01-01

The JSC/NESC team has successfully demonstrated Thermal Runaway (TR) risk reduction in a lithium ion battery for human space flight by developing and implementing verifiable design features which interrupt energy transfer between adjacent electrochemical cells. Conventional lithium ion (li-Ion) batteries can fail catastrophically as a result of a single cell going into thermal runaway. Thermal runaway results when an internal component fails to separate electrode materials leading to localized heating and complete combustion of the lithium ion cell. Previously, the greatest control to minimize the probability of cell failure was individual cell screening. Combining thermal runaway propagation mitigation design features with a comprehensive screening program reduces both the probability, and the severity, of a single cell failure.

One-Dimensional Modelling of Marine Current Turbine Runaway Behaviour

Directory of Open Access Journals (Sweden)

Staffan Lundin

2016-04-01

Full Text Available If a turbine loses its electrical load, it will rotate freely and increase speed, eventually achieving that rotational speed which produces zero net torque. This is known as a runaway situation. Unlike many other types of turbine, a marine current turbine will typically overshoot the final runaway speed before slowing down and settling at the runaway speed. Since the hydrodynamic forces acting on the turbine are dependent on rotational speed and acceleration, turbine behaviour during runaway becomes important for load analyses during turbine design. In this article, we consider analytical and numerical models of marine current turbine runaway behaviour in one dimension. The analytical model is found not to capture the overshoot phenomenon, while still providing useful estimates of acceleration at the onset of runaway. The numerical model incorporates turbine wake build-up and predicts a rotational speed overshoot. The predictions of the models are compared against measurements of runaway of a marine current turbine. The models are also used to recreate previously-published results for a tidal turbine and applied to a wind turbine. It is found that both models provide reasonable estimates of maximum accelerations. The numerical model is found to capture the speed overshoot well.

Measurements of the runaway electron energy during disruptions in the tokamak TEXTOR

International Nuclear Information System (INIS)

Forster, M.; Finken, K. H.; Willi, O.; Lehnen, M.; Xu, Y.

2012-01-01

Calorimetric measurements of the total runaway electron energy are carried out using a reciprocating probe during induced TEXTOR disruptions. A comparison with the energy inferred from runaway energy spectra, which are measured with a scintillator probe, is used as an independent check of the results. A typical runaway current of 100 kA at TEXTOR contains 30 to 35 kJ of runaway energy. The dependencies of the runaway energy on the runaway current, the radial probe position, the toroidal magnetic field and the predisruptive plasma current are studied. The conversion efficiency of the magnetic plasma energy into runaway energy is calculated to be up to 26%.

Runaway electrons in the SINP tokamak

Indian Academy of Sciences (India)

The runaway electrons have been studied in the start-up phase [12–14], as well as in the steady phase [15–17]. We have confined ourselves here to the initial rise phase of the discharge mainly because the runaway electrons find the initial low density (Т ) and large applied toroidal electric field ( М = Оloop 2 К), where К is ...

Suppression of Runaway Electrons by Resonant Magnetic Perturbations in TEXTOR Disruptions

International Nuclear Information System (INIS)

Lehnen, M.; Bozhenkov, S. A.; Abdullaev, S. S.; TEXTOR Team,; Jakubowski, M. W.

2008-01-01

The generation of runaway electrons in the international fusion experiment ITER disruptions can lead to severe damage at plasma facing components. Massive gas injection might inhibit the generation process, but the amount of gas needed can affect, e.g., vacuum systems. Alternatively, magnetic perturbations can suppress runaway generation by increasing the loss rate. In TEXTOR disruptions runaway losses were enhanced by the application of resonant magnetic perturbations with toroidal mode number n=1 and n=2. The disruptions are initiated by fast injection of about 3x10 21 argon atoms, which leads to a reliable generation of runaway electrons. At sufficiently high perturbation levels a reduction of the runaway current, a shortening of the current plateau, and the suppression of high energetic runaways are observed. These findings indicate the suppression of the runaway avalanche during disruptions

Conversion of magnetic energy to runaway kinetic energy during the termination of runaway current on the J-TEXT tokamak

Science.gov (United States)

Dai, A. J.; Chen, Z. Y.; Huang, D. W.; Tong, R. H.; Zhang, J.; Wei, Y. N.; Ma, T. K.; Wang, X. L.; Yang, H. Y.; Gao, H. L.; Pan, Y.; the J-TEXT Team

2018-05-01

A large number of runaway electrons (REs) with energies as high as several tens of mega-electron volt (MeV) may be generated during disruptions on a large-scale tokamak. The kinetic energy carried by REs is eventually deposited on the plasma-facing components, causing damage and posing a threat on the operation of the tokamak. The remaining magnetic energy following a thermal quench is significant on a large-scale tokamak. The conversion of magnetic energy to runaway kinetic energy will increase the threat of runaway electrons on the first wall. The magnetic energy dissipated inside the vacuum vessel (VV) equals the decrease of initial magnetic energy inside the VV plus the magnetic energy flowing into the VV during a disruption. Based on the estimated magnetic energy, the evolution of magnetic-kinetic energy conversion are analyzed through three periods in disruptions with a runaway current plateau.

Note: Measurement of the runaway electrons in the J-TEXT tokamak

International Nuclear Information System (INIS)

Chen, Z. Y.; Zhang, Y.; Zhang, X. Q.; Luo, Y. H.; Jin, W.; Li, J. C.; Chen, Z. P.; Wang, Z. J.; Yang, Z. J.; Zhuang, G.

2012-01-01

The runaway electrons have been measured by hard x-ray detectors and soft x-ray array in the J-TEXT tokamak. The hard x-ray radiations in the energy ranges of 0.5-5 MeV are measured by two NaI detectors. The flux of lost runaway electrons can be obtained routinely. The soft x-ray array diagnostics are used to monitor the runaway beam generated in disruptions since the soft x-ray is dominated by the interaction between runaway electrons and metallic impurities inside the plasma. With the aid of soft x-ray array, runaway electron beam has been detected directly during the formation of runaway current plateau following the disruptions.

A backward Monte Carlo method for efficient computation of runaway probabilities in runaway electron simulation

Science.gov (United States)

Zhang, Guannan; Del-Castillo-Negrete, Diego

2017-10-01

Kinetic descriptions of RE are usually based on the bounced-averaged Fokker-Planck model that determines the PDFs of RE. Despite of the simplification involved, the Fokker-Planck equation can rarely be solved analytically and direct numerical approaches (e.g., continuum and particle-based Monte Carlo (MC)) can be time consuming specially in the computation of asymptotic-type observable including the runaway probability, the slowing-down and runaway mean times, and the energy limit probability. Here we present a novel backward MC approach to these problems based on backward stochastic differential equations (BSDEs). The BSDE model can simultaneously describe the PDF of RE and the runaway probabilities by means of the well-known Feynman-Kac theory. The key ingredient of the backward MC algorithm is to place all the particles in a runaway state and simulate them backward from the terminal time to the initial time. As such, our approach can provide much faster convergence than the brute-force MC methods, which can significantly reduce the number of particles required to achieve a prescribed accuracy. Moreover, our algorithm can be parallelized as easy as the direct MC code, which paves the way for conducting large-scale RE simulation. This work is supported by DOE FES and ASCR under the Contract Numbers ERKJ320 and ERAT377.

The influence of plasma motion on disruption generated runaway electrons

International Nuclear Information System (INIS)

Russo, A.J.

1991-01-01

One of the possible consequences of disruptions is the generation of runaway electrons which can impact plasma facing components and cause damage due to high local energy deposition. This problem becomes more serious as the machine size and plasma current increases. Since large size and high currents are characteristics of proposed future machines, control of runaway generation is an important design consideration. A lumped circuit model for disruption runaway electron generation indicates that control circuitry on strongly influence runaway behavior. A comparison of disruption data from several shots on JET and D3-D with model results, demonstrate the effects of plasma motion on runaway number density and energy. 6 refs., 12 figs

Runaway Slave Advertisements: Teaching from Primary Documents

Science.gov (United States)

Costa, Tom; Doyle, Brooke

2004-01-01

In this article, the authors discuss how children can learn from runaway slave advertisements. The advertisements for runaway slaves that masters placed in eighteenth- and nineteenth-century newspapers are among the documentary sources available to teachers for studying the lives of African-American slaves. Such advertisements often describe a…

A Clustered Randomized Controlled Trial of the Positive Prevention PLUS Adolescent Pregnancy Prevention Program.

Science.gov (United States)

LaChausse, Robert G

2016-09-01

To determine the impact of Positive Prevention PLUS, a school-based adolescent pregnancy prevention program on delaying sexual intercourse, birth control use, and pregnancy. I randomly assigned a diverse sample of ninth grade students in 21 suburban public high schools in California into treatment (n = 2483) and control (n = 1784) groups that participated in a clustered randomized controlled trial. Between October 2013 and May 2014, participants completed baseline and 6-month follow-up surveys regarding sexual behavior and pregnancy. Participants in the treatment group were offered Positive Prevention PLUS, an 11-lesson adolescent pregnancy prevention program. The program had statistically significant impacts on delaying sexual intercourse and increasing the use of birth control. However, I detected no program effect on pregnancy rates at 6-month follow-up. The Positive Prevention PLUS program demonstrated positive impacts on adolescent sexual behavior. This suggests that programs that focus on having students practice risk reduction skills may delay sexual activity and increase birth control use.

Collisional avalanche exponentiation of run-away electrons in electrified plasmas

International Nuclear Information System (INIS)

Jayakumar, R.; Fleischmann, H.H.; Zweben, S.J.; Cornell Univ., Ithaca, NY

1992-07-01

In contrast to earlier expectations, it is estimated that generation of runaway electrons from close collisions of existing runaways with cold plasma electrons can be significant even for small electric fields, whenever runaways can gain energies of about 20 MeV or more. In that case, the runaway population will grow exponentially with the energy spectrum showing an exponential decrease towards higher energies.Energy gains of the required magnitude may occur in large Tokamak devices as well as in cosmic-ray generation

Running away experience and psychoactive substance use among adolescents in Taiwan: multi-city street outreach survey

Directory of Open Access Journals (Sweden)

Lew-Ting Chih-Yin

2010-01-01

Full Text Available Abstract Background This study aimed to examine: 1 the relationship between being a runaway and the time since the first absconding event and adolescent substance use; 2 whether different kinds of psychoactive substances have a different temporal relationship to the first absconding event; and 3 whether the various reasons for the first absconding event are associated with different risks of substance use. Methods Participants were drawn from the 2004-2006 nationwide outreach programs across 26 cities/towns in Taiwan. A total of 17,133 participants, age 12-18 years, who completed an anonymous questionnaire on their experience of running away and substances use and who were now living with their families, were included in the analysis. Results The lifetime risk of tobacco, alcohol, betel nut, and illegal drug/inhalant use increased steadily from adolescents who had experienced a trial runaway episode (one time lasting ≤ 1 day, to those with extended runaway experience (≥ 2 times or lasting > 1 day, when compared to those who had never ran away. Adolescents who had their first running away experience > 6 months previously had a greater risk of betel nut or illegal drug/inhalant use over the past 6-months than those with a similar experience within the last 6 months. Both alcohol and tobacco use were most frequently initiated before the first running away, whereas both betel nut and illegal drug/inhalant use were most frequently initiated after this event. When adolescents who were fleeing an unsatisfactory home life were compared to those who ran away for excitement, the risk of alcohol use was similar but the former tended to have a higher risk of tobacco, betel nut, and illegal drug/inhalant use. Conclusions More significant running away and a longer time since the first absconding experience were associated with more advanced substance involvement among adolescents now living in a family setting. Once adolescents had left home, they

Investigation of ring-like runaway electron beams in the EAST tokamak

International Nuclear Information System (INIS)

Zhou, R J; Hu, L Q; Li, E Z; Xu, M; Zhong, G Q; Xu, L Q; Lin, S Y; Zhang, J Z

2013-01-01

In the EAST tokamak, asymmetrical ring-like runaway electron beams with energy more than 30 MeV and pitch angle about 0.1 were investigated. Those runaway beams carried about 46% of the plasma current and located around the q = 2 rational surface when m/n = 1/1 and m/n = 2/1 MHD modes existed in the plasma. Those runaway beams changed from a hollow to a filled structure during the slow oscillations in the discharge about every 0.2 s, which correlated with a large step-like jump in electron cyclotron emission (ECE) signals, a big spike-like perturbation in Mirnov signals and a large decrease in runaway energy. Between those slow oscillations with large magnitude, fast oscillations with small magnitude also existed about every 0.02 s, which correlated with a small step-like jump in ECE signals, a small spike-like perturbation in Mirnov signals, but no clear decrease in runaway energy and changes in the runaway beam structure. Resonant interactions occurred between runaway electrons and magnetohydrodynamic instabilities, which gave rise to fast pitch angle scattering processes of those resonant runaway electrons, and hence increased the synchrotron radiation. Theoretical calculations of the resonant interaction were given based on a test particle description. Synchrotron radiation of those resonant runaway electrons was increased by about 60% until the end of the resonant interaction. (paper)

The resonance between runaway electrons and magnetic ripple in HT-7 Tokamak

International Nuclear Information System (INIS)

Zhou Ruijie; Hu Liqun; Lu Hongwei; Lin Shiyao; Zhong Guoqiang; Xu Ping; Zhang Jizong

2011-01-01

For suppressing the energy of runaway electrons in tokamak plasma, we analyzed the X-ray energy spectra by runaway electrons in different discharges of the HT-7 tokamak experiment performed in the autumn of 2009. The resonant phenomenon between runaway electrons and magnetic ripple was found. Although, the energy of runaway electrons in the plasma core can be as high as several tens of MeV, but when they are transported to the edge, the electron energy are limited to a certain range by resonance with the magnetic ripple of different harmonic numbers. The runaway electrons under high loop voltage resonate with low step magnetic perturbations, with high energy gain; whereas the runaway electrons under low loop voltage resonate with high level magnetic perturbations, with low energy gain. Using this mechanism, the energy of runaway electrons can be restricted to a low level, and this will significantly mitigate the damage effect on the equipment caused by runaway electrons. (authors)

Evaluation of a Peer-Led Drug Abuse Risk Reduction Project for Runaway/Homeless Youths.

Science.gov (United States)

Fors, Stuart W.; Jarvis, Sara

1995-01-01

Evaluates the Drug Prevention in Youth risk reduction program that was implemented in shelters for runaway/homeless youths in the southeastern United States. An evaluation strategy was developed allowing for comparisons between peer-led, adult-led and nonintervention groups. Well-trained and motivated peer/near-peer leaders made particularly…

Disruption generated secondary runaway electrons in present day tokamaks

International Nuclear Information System (INIS)

Pankratov, I.M.; Jaspers, R.

2000-01-01

An analysis of the runaway electron secondary generation during disruptions in present day tokamaks (JET, JT-60U, TEXTOR) was made. It was shown that even for tokamaks with the plasma current I approx 100 kA the secondary generation may dominate the runaway production during disruptions. In the same time in tokamaks with I approx 1 MA the runaway electron secondary generation during disruptions may be suppressed

Study of runaway electron generation during major disruptions in JET

International Nuclear Information System (INIS)

Plyusnin, V.V.; Riccardo, V.; Jaspers, R.; Alper, B.; Kiptily, V.G.; Mlynar, J.; Popovichev, S.; Luna, E. de La; Andersson, F.

2006-01-01

Extensive analysis of disruptions in JET has helped advance the understanding of trends of disruption-generated runaway electrons. Tomographic reconstruction of the soft x-ray emission has made possible a detailed observation of the magnetic flux geometry evolution during disruptions. With the aid of soft and hard x-ray diagnostics runaway electrons have been detected at the very beginning of disruptions. A study of runaway electron parameters has shown that an approximate upper bound for the conversion efficiency of pre-disruptive plasma currents into runaways is about 60% over a wide range of plasma currents in JET. Runaway generation has been simulated with a test particle model in order to verify the results of experimental data analysis and to obtain the background for extrapolation of the existing results onto larger devices such as ITER. It was found that close agreement between the modelling results and experimental data could be achieved if in the calculations the post-disruption plasma electron temperature was assumed equal to 10 eV and if the plasma column geometry evolution is taken into account in calculations. The experimental trends and numerical simulations show that runaway electrons are a critical issue for ITER and, therefore, the development of mitigation methods, which suppress runaway generation, is an essential task

Sex education for young adolescents :enhancing parental involvement

OpenAIRE

Guillory, Dorothy

1993-01-01

The frequent incidence and seriousness of youth problems such as delinquency, runaways, drug abuse, and suicide create significant social problems. The tumultuous nature of adolescence, which offers a tremendous challenge to families, has captured the public's attention through adolescent sexuality (Herz, Goldberg, & Reis, 1984; Trussell, 1988). Considered a serious national health issue, the sexual behavior of adolescents is an area of increased concern as is the inci...

Adolescent suicide prevention. Current research and social policy implications.

Science.gov (United States)

Garland, A F; Zigler, E

1993-02-01

The rate of adolescent suicide has increased dramatically in the past few decades, prompting several interventions to curb the increase. Unfortunately, many of the intervention efforts have not benefited from current research findings because the communication between researchers and those who develop the interventions is inadequate. Of specific concern are the increasingly popular curriculum-based suicide prevention programs, which have not demonstrated effectiveness and may contain potentially deleterious components. This article reviews the current epidemiological research in adolescent suicide and suggests how this knowledge could be used more effectively to reduce the rate of adolescent suicide. Recommendations include support for integrated primary prevention efforts; suicide prevention education for professionals; education and policies on firearm management; education for the media about adolescent suicide; more efficient identification and treatment of at-risk youth, including those exposed to suicidal behavior; crisis intervention; and treatment for suicide attempters.

Acceleration of runaway electrons in solar flares

Science.gov (United States)

Moghaddam-Taaheri, E.; Goertz, C. K.

1990-01-01

The dc electric field acceleration of electrons out of a thermal plasma and the evolution of the runaway tail are studied numerically, using a relativistic quasi-linear code based on the Ritz-Galerkin method and finite elements. A small field-aligned electric field is turned on at a certain time. The resulting distribution function from the runaway process is used to calculate the synchrotron emission during the evolution of the runaway tail. It is found that, during the runaway tail formation, which lasts a few tens of seconds for typical solar flare conditions, the synchrotron emission level is low, almost ot the same order as the emission from the thermal plasma, at the high-frequency end of the spectrum. However, the emission is enhanced explosively in a few microseconds by several orders of magnitude at the time the runaway tail stops growing along the magnetic field and tends toward isotropy due to the pitch-angle scattering of the fast particles. Results indicate that, in order to account for the observed synchrotron emission spectrum of a typical solar flare, the electric field acceleration phase must be accompanied or preceded by a heating phase which yields an enhanced electron temperature of about 2-15 keV in the flare region if the electric field is 0.1-0.2 times the Dreicer field and cyclotron-to-plasma frequency ratios are of order 1-2.

[Current Guidelines to Prevent Obesity in Childhood and Adolescence].

Science.gov (United States)

Blüher, S; Kromeyer-Hauschild, K; Graf, C; Grünewald-Funk, D; Widhalm, K; Korsten-Reck, U; Markert, J; Güssfeld, C; Müller, M J; Moss, A; Wabitsch, M; Wiegand, S

2016-01-01

Current guidelines for the prevention of obesity in childhood and adolescence are presented. A literature search was performed in Medline via PubMed, and appropriate studies were analysed. Programs to prevent childhood obesity were to date mainly school-based. Effects were limited to date. Analyses tailored to different age groups show that prevention programs have the best effects in younger children (adolescence, school-based interventions were most effective when adolescents were directly addressed. To date, obesity prevention programs have mainly focused on behavior oriented prevention. Recommendations for condition oriented prevention have been suggested by the German Alliance of Non-communicable Diseases and include one hour of physical activity at school, promotion of healthy food choices by taxing unhealthy foods, mandatory quality standards for meals at kindergarten and schools as well as a ban on unhealthy food advertisement addressing children. Behavior oriented prevention programs showed hardly any or only limited effects in the long term. Certain risk groups for the development of obesity are not reached effectively by available programs. Due to the heterogeneity of available studies, universally valid conclusions cannot be drawn. The combination with condition oriented prevention, which has to counteract on an obesogenic environment, is crucial for sustainable success of future obesity prevention programs. © Georg Thieme Verlag KG Stuttgart · New York.

Study of runaway electron generation process during major disruptions in JET

International Nuclear Information System (INIS)

Plyusnin, V.V.; Riccardo, V.; Alper, B.; Kiptily, V.G.; Popovichev, S.; Helander, P.; Jaspers, R.; Mlynar, J.; Luna, E. de La; Andersson, F.

2005-01-01

The analysis of a large number of JET disruptions has provided further data on the trends of the disruption induced runaway process in large tokamaks. The role of primary runaway electrons generated at the thermal quench has been examined to assess their influence on secondary avalanching, which is recognized as a main source of large runaway currents created during disruptions. The tomographic reconstruction of the soft X-ray emission during the thermal quench has made possible the observation of the magnetic flux geometry evolution and the locating of the most probable zones for generation and confinement of the primary runaway electrons. Runaway currents have been found to increase with toroidal magnetic field and pre-disruption plasma current values. The average conversion efficiency is approximately 40-45% at a wide range of plasma currents. This agrees well with results of numerical simulations, which predict similar conversion rates at an assumed post-disruption plasma electron temperature of 10 eV. The experimental trends and numerical simulations show that runaway electrons might be an issue for ITER and therefore it remains prudent to develop mitigation methods, which suppress runaway generation. (author)

Prevention for Pediatric and Adolescent Migraine.

Science.gov (United States)

Hickman, Carolyn; Lewis, Kara Stuart; Little, Robert; Rastogi, Reena Gogia; Yonker, Marcy

2015-01-01

Children and adolescents can experience significant disability from frequent migraine. A number of tools have been developed to help quantify the impact of migraine in this population. Many preventative medications used in adults are routinely used to prevent migraines in children, although there has been less rigorous study. This article reviews the indications and evidence for the use of migraine preventatives, such as antidepressants, antihypertensives, anticonvulsants, antihistamines, and botulinum toxin, in this population. © 2015 American Headache Society.

RUNAWAY STARS AND THE ESCAPE OF IONIZING RADIATION FROM HIGH-REDSHIFT GALAXIES

International Nuclear Information System (INIS)

Conroy, Charlie; Kratter, Kaitlin M.

2012-01-01

Approximately 30% of all massive stars in the Galaxy are runaways with velocities exceeding 30 km s –1 . Their high speeds allow them to travel ∼0.1-1 kpc away from their birthplace before they explode at the end of their several Myr lifetimes. At high redshift, when galaxies were much smaller than in the local universe, runaways could venture far from the dense inner regions of their host galaxies. From these large radii, and therefore low column densities, much of their ionizing radiation is able to escape into the intergalactic medium. Runaways may therefore significantly enhance the overall escape fraction of ionizing radiation, f esc , from small galaxies at high redshift. We present simple models of the high-redshift runaway population and its impact on f esc as a function of halo mass, size, and redshift. We find that the inclusion of runaways enhances f esc by factors of ≈1.1-8, depending on halo mass, galaxy geometry, and the mechanism of runaway production, implying that runaways may contribute 50%-90% of the total ionizing radiation escaping from high-redshift galaxies. Runaways may therefore play an important role in reionizing the universe.

Runaway breakdown and electrical discharges in thunderstorms

Science.gov (United States)

Milikh, Gennady; Roussel-Dupré, Robert

2010-12-01

This review considers the precise role played by runaway breakdown (RB) in the initiation and development of lightning discharges. RB remains a fundamental research topic under intense investigation. The question of how lightning is initiated and subsequently evolves in the thunderstorm environment rests in part on a fundamental understanding of RB and cosmic rays and the potential coupling to thermal runaway (as a seed to RB) and conventional breakdown (as a source of thermal runaways). In this paper, we describe the basic mechanism of RB and the conditions required to initiate an observable avalanche. Feedback processes that fundamentally enhance RB are discussed, as are both conventional breakdown and thermal runaway. Observations that provide clear evidence for the presence of energetic particles in thunderstorms/lightning include γ-ray and X-ray flux intensifications over thunderstorms, γ-ray and X-ray bursts in conjunction with stepped leaders, terrestrial γ-ray flashes, and neutron production by lightning. Intense radio impulses termed narrow bipolar pulses (or NBPs) provide indirect evidence for RB particularly when measured in association with cosmic ray showers. Our present understanding of these phenomena and their enduring enigmatic character are touched upon briefly.

Experimental Investigation of Runaway Electron Generation in Textor

NARCIS (Netherlands)

R. Jaspers,; Finken, K.H.; Mank, G.; Hoenen, F.; Boedo, J. A.; Cardozo, N. J. L.; Schüller, F. C.

1993-01-01

An experimental study of the generation of runaway electrons in TEXTOR has been performed. From the infrared synchrotron radiation emitted by relativistic electrons, the number of runaway electrons can be obtained as a function of time. In low density discharges (n(e)BAR < 1 X 10(19) m-3)

On the origin of high-velocity runaway stars

NARCIS (Netherlands)

Gvaramadze, V.V.; Gualandris, A.; Portegies Zwart, S.

2009-01-01

We explore the hypothesis that some high-velocity runaway stars attain their peculiar velocities in the course of exchange encounters between hard massive binaries and a very massive star (either an ordinary 50-100 M-circle dot star or a more massive one, formed through runaway mergers of ordinary

30 CFR 56.9302 - Protection against moving or runaway railroad equipment.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection against moving or runaway railroad..., and Loading and Dumping Sites § 56.9302 Protection against moving or runaway railroad equipment. Stopblocks, derail devices, or other devices that protect against moving or runaway rail equipment shall be...

30 CFR 57.9302 - Protection against moving or runaway railroad equipment.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Protection against moving or runaway railroad..., Railroads, and Loading and Dumping Sites § 57.9302 Protection against moving or runaway railroad equipment. Stopblocks, derail devices, or other devices that protect against moving or runaway rail equipment shall be...

Preventing adolescent suicide: a community takes action.

Science.gov (United States)

Pirruccello, Linda M

2010-05-01

Suicide is the third leading cause of death for adolescents and young people in the United States. The etiology of suicide in this population has eluded policy makers, researchers, and communities. Although many suicide prevention programs have been developed and implemented, few are evidence-based in their effectiveness in decreasing suicide rates. In one northern California community, adolescent suicide has risen above the state's average. Two nurses led an effort to develop and implement an innovative grassroots community suicide prevention project targeted at eliminating any further teen suicide. The project consisted of a Teen Resource Card, a community resource brochure targeted at teens, and education for the public and school officials to raise awareness about this issue. This article describes this project for other communities to use as a model. Risk and protective factors are described, and a comprehensive background of adolescent suicide is provided.

Effect of runaway electrons and VDE's on ITER first wall

International Nuclear Information System (INIS)

Raffray, A.R.; Cardella, A.; Federici, G.; Ioki, K.; Parker, R.; Akiba, M.; Ezato, K.

1998-01-01

Runaway electron and VDE energy deposition transients pose a major Be and W armour lifetime issue depending on their frequencies. The impact is more severe in the case of W because of the high minimum armour thickness required to prevent Cu from melting. Use of W armour should be limited to regions where such 'slow' high energy deposition transients are highly unlikely. Future effort is required to better understand and characterise these events and to develop design measures to address the issue. (author)

[The development of an integrated suicide-violence prevention program for adolescents].

Science.gov (United States)

Park, Hyun Sook

2008-08-01

The purpose of this study was to develop an integrated suicide-violence prevention program for adolescents. Another purpose was to evaluate the effects of the integrated suicide-violence prevention program on self-esteem, parent-child communication, aggression, and suicidal ideation in adolescents. The study employed a quasi-experimental design. Participants for the study were high school students, 24 in the experimental group and 25 in the control group. Data was analyzed by using the SPSS/WIN. 11.5 program with chi2 test, t-test, and 2-way ANOVA. Participants in the integrated suicide-violence prevention program reported increased self-esteem scores, which was significantly different from those in the control group. Participants in the integrated suicide-violence prevention program reported decreased aggression and suicidal ideation scores, which was significantly different from those in the control group. The integrated suicide-violence prevention program was effective in improving self-esteem and decreasing aggression and suicidal ideation for adolescents. Therefore, this approach is recommended as the integrated suicide-violence prevention strategy for adolescents.

Adolescents' mental health and the Greek family: preventive aspects.

Science.gov (United States)

Ierodiakonou, C S

1988-03-01

Preventive mental health measures can be properly planned only if the various factors leading to the adolescent's personality structure are extensively investigated. Starting with the specific attitudes of a couple towards genetic counselling, the disadvantages of urbanization and of the dissolution of the traditional extended family are discussed with regard to their effect on the younger members. Data are produced concerning the child-rearing practices of Greek in comparison to American parents and their effect on the adolescent's emotional life. Extreme dependence on the family, pressure for school achievements, lack of sexual education, etc. are characteristic of the stresses a Greek adolescent undergoes. Socio-cultural conditions, like immigration, adoption, etc. are shown to have a different psychological effect on an adolescent in Greece than in America. Specific stresses regarding the adolescent's future, like preparing for university entrance examinations, are discussed and preventive measures are proposed.

Runaway electrons dynamics and confinement in Tore-Supra

International Nuclear Information System (INIS)

Chatelier, M.; Geraud, A.; Joyer, P.; Martin, G.; Rax, J.M.

1989-01-01

The lack of energy of runaway electrons, confined in Tore Supra tokamak, is studied. Ohmic discharges, obtained with helium gas, exhibit a small amount of runaway electrons on both hard X-ray monitors and neutron sensors. The observations show an important lack of energy for runaway electrons confined in Tore Supra. It is assumed to be dued to a small pitch-angle scattering (a few degrees), and many candidates for this are compared: the strongest known one collisions seems not to be enough by an order of magnitude. Density and magnetic scans on Tore Supra are needed to discriminate between enhanced collisional scattering processes and purely magnetic phenomena

Long-term health and medical cost impact of smoking prevention in adolescence.

Science.gov (United States)

Wang, Li Yan; Michael, Shannon L

2015-02-01

To estimate smoking progression probabilities from adolescence to young adulthood and to estimate long-term health and medical cost impacts of preventing smoking in today's adolescents. Using data from the National Longitudinal Study of Adolescent Health (Add Health), we first estimated smoking progression probabilities from adolescence to young adulthood. Then, using the predicted probabilities, we estimated the number of adolescents who were prevented from becoming adult daily smokers as a result of a hypothetical 1 percentage point reduction in the prevalence of ever smoking in today's adolescents. We further estimated lifetime medical costs saved and quality-adjusted life years (QALYs) gained as a result of preventing adolescents from becoming adult daily smokers. All costs were in 2010 dollars. Compared with never smokers, those who had tried smoking at baseline had higher probabilities of becoming current or former daily smokers at follow-up regardless of baseline grade or sex. A hypothetical 1 percentage point reduction in the prevalence of ever smoking in 24.5 million students in 7th-12th grades today could prevent 35,962 individuals from becoming a former daily smoker and 44,318 individuals from becoming a current daily smoker at ages 24-32 years. As a result, lifetime medical care costs are estimated to decrease by $1.2 billion and lifetime QALYs is estimated to increase by 98,590. Effective smoking prevention programs for adolescents go beyond reducing smoking prevalence in adolescence; they also reduce daily smokers in young adulthood, increase QALYs, and reduce medical costs substantially in later life. This finding indicates the importance of continued investment in effective youth smoking prevention programs. Published by Elsevier Inc.

Runaway in the landscape

International Nuclear Information System (INIS)

Becker, Katrin; Becker, Melanie; Walcher, Johannes

2007-01-01

We consider flux compactifications of type IIB string theory on the mirror of a rigid Calabi-Yau. In special cases, these models are dual to the type IIA flux vacua with runaway direction in flux space. We show that new weak coupling AdS solutions can be found for large complex structure, while Minkowski solutions with all moduli stabilized are confined to be at strong coupling. The existence of these solutions, as found in a previous work, is nevertheless guaranteed by a nonrenormalization theorem of the type IIB flux superpotential. Based on our results, we are led to the conjecture that supersymmetric runaway directions in flux space are always accompanied by a spectrum of moduli masses reaching down to the AdS scale. This could be violated in a nonsupersymmetric situation

Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery

Directory of Open Access Journals (Sweden)

Jingjing Liu

2017-02-01

Full Text Available This study addresses the effects of the SOC (State of Charge and the charging–discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging.

Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery.

Science.gov (United States)

Liu, Jingjing; Wang, Zhirong; Gong, Junhui; Liu, Kai; Wang, Hao; Guo, Linsheng

2017-02-25

This study addresses the effects of the SOC (State of Charge) and the charging-discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging.

Runaway electrons and rational q-surfaces in a tokamak

International Nuclear Information System (INIS)

Cheetham, A.D.; Hogg, G.R.; Kuwahara, H.; Morton, A.H.

1983-01-01

Results of measurements with LT-4 of runaway electron behaviour during the current rise stage of discharges when q = rBsub(T)/RBsub(p) (where r and R are minor and major radii, Bsub(T) and Bsub(p) are toroidal and poloidal magnetic fields) is changing continuously are reported. The results establish a role for outward moving rational q regions in removing runaway electrons from a tokamak plasma. The model indicates that as well as carrying a proportion of low energy runaways with them the rational q regions also scatter high energy electrons from the discharge. This leads to an upper limit for the energy of fully confined electrons. The size of the runaway population might be minimised by controlling the rate of movement of rational surfaces. This would be achieved by programming the rate of rise of the plasma current

Runaway greenhouse atmospheres: Applications to Earth and Venus

International Nuclear Information System (INIS)

Kasting, J.F.

1991-01-01

Runaway greenhouse atmospheres are discussed from a theoretical standpoint and with respect to various practical situation in which they might occur. The following subject areas are covered: (1) runaway greenhouse atmospheres; (2) moist greenhouse atmospheres; (3) loss of water from Venus; (4) steam atmosphere during accretion; and (5) the continuously habitable zone

Runaway greenhouse atmospheres: Applications to Earth and Venus

Science.gov (United States)

Kasting, James F.

1991-01-01

Runaway greenhouse atmospheres are discussed from a theoretical standpoint and with respect to various practical situation in which they might occur. The following subject areas are covered: (1) runaway greenhouse atmospheres; (2) moist greenhouse atmospheres; (3) loss of water from Venus; (4) steam atmosphere during accretion; and (5) the continuously habitable zone.

A review of educational-based gambling prevention programs for adolescents

Directory of Open Access Journals (Sweden)

Boon Chin Oh

2017-06-01

Full Text Available Abstracts Educational-based problem gambling prevention programs are important avenues in targeting at-risk behaviors among adolescents to prevent an escalation of problematic behaviors into adulthood. The aim of this review is to examine features pertinent to effective educational-based programs in the area of adolescent problem gambling prevention in hopes of providing a foundation and future suggestions for preventive efforts. A stronger understanding of this research area will be essential in ensuring that past practical and theoretical advancements are integrated into the development of future programs.

Quasi-linear analysis of the extraordinary electron wave destabilized by runaway electrons

Energy Technology Data Exchange (ETDEWEB)

Pokol, G. I.; Kómár, A.; Budai, A. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Budapest (Hungary); Stahl, A.; Fülöp, T. [Department of Applied Physics, Chalmers University of Technology, Göteborg (Sweden)

2014-10-15

Runaway electrons with strongly anisotropic distributions present in post-disruption tokamak plasmas can destabilize the extraordinary electron (EXEL) wave. The present work investigates the dynamics of the quasi-linear evolution of the EXEL instability for a range of different plasma parameters using a model runaway distribution function valid for highly relativistic runaway electron beams produced primarily by the avalanche process. Simulations show a rapid pitch-angle scattering of the runaway electrons in the high energy tail on the 100–1000 μs time scale. Due to the wave-particle interaction, a modification to the synchrotron radiation spectrum emitted by the runaway electron population is foreseen, exposing a possible experimental detection method for such an interaction.

Runaway electron generation during plasma shutdown by killer pellet injection

International Nuclear Information System (INIS)

Gal, K; Feher, T; Smith, H; Fueloep, T; Helander, P

2008-01-01

Tokamak discharges are sometimes terminated by disruptions that may cause large mechanical and thermal loads on the vessel. To mitigate disruption-induced problems it has been proposed that 'killer' pellets could be injected into the plasma in order to safely terminate the discharge. Killer pellets enhance radiative energy loss and thereby lead to rapid cooling and shutdown of the discharge. But pellets may also cause runaway electron generation, as has been observed in experiments in several tokamaks. In this work, runaway dynamics in connection with deuterium or carbon pellet-induced fast plasma shutdown is considered. A pellet code, which calculates the material deposition and initial cooling caused by the pellet is coupled to a runaway code, which determines the subsequent temperature evolution and runaway generation. In this way, a tool has been created to test the suitability of different pellet injection scenarios for disruption mitigation. If runaway generation is avoided, the resulting current quench times are too long to safely avoid large forces on the vessel due to halo currents

Results of prevention programs with adolescents.

Science.gov (United States)

Perry, C L

1987-09-01

Programs for preventing smoking and alcohol and drug abuse have radically changed in the past decade. Instead of being regarded as a health or discipline problem that involves only a few deviant adolescents, drug use has begun to be viewed as social behavior that is functional for adolescents, not capricious, and is normative for that population. The most successful prevention programs have sought to delay the onset of tobacco use. Based on theoretical and etiological research, these programs target factors that have repeatedly been predictive of adolescent smoking, alcohol and drug use. The programs teach adolescents (1) why people their age smoke tobacco or use alcohol and drugs; (2) how these meanings get established by peers, older role models and advertising; (3) how to resist these influences to smoke or to use alcohol and drugs; and (4) life skills and competencies to counterbalance the functions that drug use serves. Because of the association with the onset of smoking and the onset of using other drugs, these strategies are being studied for alcohol use and other drugs. In addition, elected peer leaders are trained to conduct these activities with their classmates and act as new role models for non-use. Evaluations of these approaches are optimistic. Studies in northern California and Minnesota reveal 50-70% reductions in the onset of smoking. Botvin's 'Life Skills Training' program demonstrates success in delaying heavy alcohol and marijuana use.

The Prevention of Adolescent Smoking: A Public Health Priority.

Science.gov (United States)

Harken, Laurel S.

1987-01-01

Discusses ways to prevent adolescents from smoking by preparing them to deal with problematic situations. Focuses on problem-solving and decision-making skills. Prevention strategies are also discussed. (RB)

Are some of the luminous high-latitude stars accretion-powered runaways?

International Nuclear Information System (INIS)

Leonard, P.J.T.; Hills, J.G.; Dewey, R.J.

1992-01-01

It is well known that (1) runaway stars can be produced via supernova explosions in close binary systems, (2) most of such runaways should possess neutron star companions, and (3) neutron stars receive randomly oriented kicks of ≅ 100 to 200 km s -1 at birth. We find that this kick sometimes has the right amplitude and direction to make the neutron star fall into the runaway. Accretion onto a neutron star is a source of energy that is roughly an order of magnitude more mass efficient than nuclear burning. Thus, runaways containing neutron stars may live much longer than would normally be expected, which would allow them to travel great distances from their birthplaces during their lifetimes. Some of the early B-type stars far from the Galactic plane and the high-latitude F and G-type supergiants may be accretion-powered runaway stars

Electromagnetic waves destabilized by runaway electrons in near-critical electric fields

Energy Technology Data Exchange (ETDEWEB)

Komar, A.; Pokol, G. I. [Department of Nuclear Techniques, Budapest University of Technology and Economics, Association EURATOM, H-1111 Budapest (Hungary); Fueloep, T. [Department of Applied Physics, Nuclear Engineering, Chalmers University of Technology and Euratom-VR Association, Goeteborg (Sweden)

2013-01-15

Runaway electron distributions are strongly anisotropic in velocity space. This anisotropy is a source of free energy that may destabilize electromagnetic waves through a resonant interaction between the waves and the energetic electrons. In this work, we investigate the high-frequency electromagnetic waves that are destabilized by runaway electron beams when the electric field is close to the critical field for runaway acceleration. Using a runaway electron distribution appropriate for the near-critical case, we calculate the linear instability growth rate of these waves and conclude that the obliquely propagating whistler waves are most unstable. We show that the frequencies, wave numbers, and propagation angles of the most unstable waves depend strongly on the magnetic field. Taking into account collisional and convective damping of the waves, we determine the number density of runaways that is required to destabilize the waves and show its parametric dependences.

Influence of the angular scattering of electrons on the runaway threshold in air

DEFF Research Database (Denmark)

Chanrion, O.; Bonaventura, Z.; Bourdon, A.

2016-01-01

The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy...... electrons that run away in electric fields associated with thunderstorms. In this paper, we discuss the runaway threshold definition with a particular interest in the influence of the angular scattering for electron energy close to the threshold. In order to understand the mechanism of runaway, we compare...... scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation....

Study of the generation and suppression of runaway currents in provoked disruptions in J-TEXT

Energy Technology Data Exchange (ETDEWEB)

Chen, Z.Y., E-mail: zychen@mail.hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Chen, Z.P., E-mail: zpchen@mail.hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China); Zhang, Y.; Jin, W.; Fang, D.; Ba, W.G.; Wang, Z.J.; Zhang, M.; Yang, Z.J.; Ding, Y.H.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China)

2012-05-14

Runaway currents following disruptions have an important effect on the first wall for the next generation tokamak. The behaviors of runaway currents following intentional provoked disruptions have been investigated in the J-TEXT tokamak. It is found that the runaway current generation following provoked disruptions depends on both the toroidal magnetic field and the plasma current. The conversion efficiency of pre-disruptive plasma currents into runaway currents is in the ranges of 30% to 60% in J-TEXT. The runaway currents can be avoided by the intensive gas puffing of H{sub 2} due to the low multiplication factor in J-TEXT. -- Highlights: ► The regime of runaway generation in disruptions in J-TEXT has been established. ► The magnetic field threshold for runaway current generation in disruptions is 2.2 T. ► The conversion efficiency of runaway current is in the ranges of 30% to 60%. ► The runaway currents can be avoided by the intensive gas puffing of H{sub 2}.

Study of the generation and suppression of runaway currents in provoked disruptions in J-TEXT

International Nuclear Information System (INIS)

Chen, Z.Y.; Chen, Z.P.; Zhang, Y.; Jin, W.; Fang, D.; Ba, W.G.; Wang, Z.J.; Zhang, M.; Yang, Z.J.; Ding, Y.H.; Zhuang, G.

2012-01-01

Runaway currents following disruptions have an important effect on the first wall for the next generation tokamak. The behaviors of runaway currents following intentional provoked disruptions have been investigated in the J-TEXT tokamak. It is found that the runaway current generation following provoked disruptions depends on both the toroidal magnetic field and the plasma current. The conversion efficiency of pre-disruptive plasma currents into runaway currents is in the ranges of 30% to 60% in J-TEXT. The runaway currents can be avoided by the intensive gas puffing of H 2 due to the low multiplication factor in J-TEXT. -- Highlights: ► The regime of runaway generation in disruptions in J-TEXT has been established. ► The magnetic field threshold for runaway current generation in disruptions is 2.2 T. ► The conversion efficiency of runaway current is in the ranges of 30% to 60%. ► The runaway currents can be avoided by the intensive gas puffing of H 2 .

Preventing the Onset of Child Sexual Abuse by Targeting Young Adolescents With Universal Prevention Programming

Science.gov (United States)

Letourneau, Elizabeth J.; Schaeffer, Cindy M.; Bradshaw, Catherine P.; Feder, Kenneth A.

2017-01-01

Child sexual abuse (CSA) is a serious public health problem that increases risk for physical and mental health problems across the life course. Young adolescents are responsible for a substantial portion of CSA offending, yet to our knowledge, no validated prevention programs that target CSA perpetration by youth exist. Most existing efforts to address CSA rely on reactive criminal justice policies or programs that teach children to protect themselves; neither approach is well validated. Given the high rates of desistance from sexual offending following a youth’s first CSA-related adjudication, it seems plausible that many youth could be prevented from engaging in their first offense. The goal of this article is to examine how school-based universal prevention programs might be used to prevent CSA perpetrated by adolescents. We review the literature on risk and protective factors for CSA perpetration and identify several promising factors to target in an intervention. We also summarize the literature on programs that have been effective at preventing adolescent dating violence and other serious problem behaviors. Finally, we describe a new CSA prevention program under development and early evaluation and make recommendations for program design characteristics, including unambiguous messaging, parental involvement, multisession dosage, skills practice, and bystander considerations. PMID:28413921

Preventing toxicomania and addictive behaviour in adolescence.

Science.gov (United States)

Manceaux, Pauline; Maricq, Aurélie; Zdanowicz, Nicolas; Reynaert, Christine

2013-09-01

Drug addicts are more and more stigmatized in our society. Recent data show a connection between substance abuse and other behaviors considered normal, such as passionate love. Adolescence is characterized by a biopsychosocial, cognitive and neurodevelopmental immaturity. This article aims to understand if these subjects are more likely to develop addictions to certain products or addictive behaviors such as passionate love. It also offers a better understanding of the current models for prevention of substance abuse during adolescence. After defining the roles played, in the brain, by dopamine and by the reward circuit, as well as the different stages of development of the human brain, we compared neurobiological data and imaging studies both in cases of passionate love and substance addiction during adolescence. The brain imaging studies highlight the role of the prefrontal cortex in the cognitive and behavioral aspects of the addictive phenomenon. Now, the maturation of the prefrontal cortex occurs during adolescence, as do significant peaks in the expression of dopamine. These studies also suggest an increase in cortical activation (nucleus accumbens and amygdala) when processing emotional information, which is also increased during adolescence. Taken together, the results show a parallel between addiction and love relations, both at the level of neuroscience and imaging. A greater emotional lability and sensitivity may play a role in the higher incidence of substance abuse and dependence in love observed at this age. Preventing the use of illegal substances among young people therefore requires a very specific approach.

Models of primary runaway electron distribution in the runaway vortex regime

International Nuclear Information System (INIS)

Guo, Zehua; Tang, Xian-Zhu; McDevitt, Christopher J.

2017-01-01

Generation of runaway electrons (RE) beams can possibly induce the most deleterious effect of tokamak disruptions. A number of recent numerical calculations have confirmed the formation of a RE bump in their energy distribution by taking into account Synchrontron radiational damping force due to RE’s gyromotions. Here, we present a detailed examination on how the bump location changes at different pitch-angle and the characteristics of the RE pitch-angle distribution. Although REs moving along the magnetic field are preferably accelerated and then populate the phase-space of larger pitch-angle mainly through diffusions, an off-axis peak can still form due to the presence of the vortex structure which causes accumulation of REs at low pitch-angle. A simplified Fokker- Planck model and its semi-analytical solutions based on local expansions around the O point is used to illustrate the characteristics of RE distribution around the O point of the runaway vortex in phase-space. The calculated energy location of the O point together with the local energy and pitch-angle distributions agree with the full numerical solution.

Low Simulated Radiation Limit for Runaway Greenhouse Climates

Science.gov (United States)

Goldblatt, Colin; Robinson, Tyler D.; Zahnle, Kevin J.; Crisp, David

2013-01-01

Terrestrial planet atmospheres must be in long-term radiation balance, with solar radiation absorbed matched by thermal radiation emitted. For hot moist atmospheres, however, there is an upper limit on the thermal emission which is decoupled from the surface temperature. If net absorbed solar radiation exceeds this limit the planet will heat uncontrollably, the so-called \\runaway greenhouse". Here we show that a runaway greenhouse induced steam atmosphere may be a stable state for a planet with the same amount of incident solar radiation as Earth has today, contrary to previous results. We have calculated the clear-sky radiation limits at line-by-line spectral resolution for the first time. The thermal radiation limit is lower than previously reported (282 W/sq m rather than 310W/sq m) and much more solar radiation would be absorbed (294W/sq m rather than 222W/sq m). Avoiding a runaway greenhouse under the present solar constant requires that the atmosphere is subsaturated with water, and that cloud albedo forcing exceeds cloud greenhouse forcing. Greenhouse warming could in theory trigger a runaway greenhouse but palaeoclimate comparisons suggest that foreseeable increases in greenhouse gases will be insufficient to do this.

Interventions for preventing eating disorders in children and adolescents.

Science.gov (United States)

Pratt, B M; Woolfenden, S R

2002-01-01

Eating disorders represent an extremely difficult condition to treat and patients consume an enormous amount of mental health energy and resources. Being young, female, and dieting are some of the few identified risk factors that have been reliably linked to the development of eating disorders, and several prevention eating disorder prevention programs have been developed and trialed with children and adolescents. The purpose of this systematic review is to evaluate the effectiveness of eating disorder prevention programs for children and adolescents both in the general population and those determined to be at risk. 1. To determine if eating disorder prevention programs are effective in promoting healthy eating attitudes and behaviours in children and adolescents; 2. To determine if eating disorder prevention programs are effective in promoting psychological factors that protect children and adolescents from developing eating disorders; 3. To determine if eating disorder prevention programs are effective in promoting satisfactory physical health in children and adolescents; 4. To determine if eating disorder prevention programs have a long-term, sustainable, and positive impact on the mental and physical health of children and adolescents; and, 5. To determine the safety of eating disorder prevention programs in terms of possible harmful consequences on the mental or physical health of children and adolescents. Relevant trials are identified through searching the Cochrane Controlled Trial Register (CCTR) and relevant biomedical and social science databases. All terms necessary to detect prevention programs and the participant groups are used. A strategy to locate randomised controlled trials is used. Other sources of information are the bibliographies of systematic and non-systematic reviews and reference lists from articles identified through the search strategy. In order to identify unpublished studies, experts in the field are contacted by letter and

Fokker-Planck simulations of knock-on electron runaway avalanche and bursts in tokamaks

International Nuclear Information System (INIS)

Chiu, S.C.; Rosenbluth, M.N.; Harvey, R.W.; Chan, V.S.

1998-01-01

The avalanche of runaway electrons in an ohmic tokamak plasma triggered by knock-on collisions of traces of energetic electrons with the bulk electrons is simulated by the bounce averaged Fokker-Planck code, CQL3D. It is shown that even when the electric field is small for the production of Dreicer runaways, the knock-on collisions can produce significant runaway electrons in a fraction of a second at typical reactor parameters. The energy spectrum of these knock-on runaways has a characteristic temperature. The growth rate and temperature of the runaway distribution are determined and compared with theory. In simulations of pellet injection into high temperature plasmas, it is shown that a burst of Dreicer runaways may also occur depending on the cooling rate due to the pellet injection. Implications of these phenomena on disruption control in reactor plasmas are discussed. (author)

First Direct Observation of Runaway-Electron-Driven Whistler Waves in Tokamaks

Science.gov (United States)

Spong, D. A.; Heidbrink, W. W.; Paz-Soldan, C.; Du, X. D.; Thome, K. E.; Van Zeeland, M. A.; Collins, C.; Lvovskiy, A.; Moyer, R. A.; Austin, M. E.; Brennan, D. P.; Liu, C.; Jaeger, E. F.; Lau, C.

2018-04-01

DIII-D experiments at low density (ne˜1019 m-3 ) have directly measured whistler waves in the 100-200 MHz range excited by multi-MeV runaway electrons. Whistler activity is correlated with runaway intensity (hard x-ray emission level), occurs in novel discrete frequency bands, and exhibits nonlinear limit-cycle-like behavior. The measured frequencies scale with the magnetic field strength and electron density as expected from the whistler dispersion relation. The modes are stabilized with increasing magnetic field, which is consistent with wave-particle resonance mechanisms. The mode amplitudes show intermittent time variations correlated with changes in the electron cyclotron emission that follow predator-prey cycles. These can be interpreted as wave-induced pitch angle scattering of moderate energy runaways. The tokamak runaway-whistler mechanisms have parallels to whistler phenomena in ionospheric plasmas. The observations also open new directions for the modeling and active control of runaway electrons in tokamaks.

Observation of thermal quench induced by runaway electrons in magnetic perturbation

Science.gov (United States)

Cheon, MunSeong; Seo, Dongcheol; Kim, Junghee

2018-04-01

Experimental observations in Korea Superconducting Tokamak Advanced Research (KSTAR) plasmas show that a loss of pre-disruptive runaway electrons can induce a rapid radiative cooling of the plasma, by generating impurity clouds from the first wall. The synchrotron radiation image shows that the loss of runaway electrons occurs from the edge region when the resonant magnetic perturbation is applied on the plasma. When the impact of the runaway electrons on the wall is strong enough, a sudden drop of the electron cyclotron emission (ECE) signal occurs with the characteristic plasma behaviors such as the positive spike and following decay of the plasma current, Dα spike, big magnetic fluctuation, etc. The visible images at this runaway loss show an evidence of the generation of impurity cloud and the following radiative cooling. When the runaway beam is located on the plasma edge, thermal quenches are expected to occur without global destruction of the magnetic structure up to the core.

Run-away electrons and plasma pinching in a high-current diode

International Nuclear Information System (INIS)

Ivanenkov, G.V.

1984-01-01

The electrons run-away process in space-confined plasma with current is considered. It has been found that the effect of the proper magnetic field of a current leads to appearance, in add tion to the Dreicer mechanism, of other run-away mechanism in the process of radial oscillations of electrons accelerating near the axis. The appearance of run-away electrons from a thermal velocities region occurs in the course of collisions as well as radial drift. The thresholds of Dreicer run-away and drift are determined. The conditions of formation of Z-pinch current envelope and its collisionless compression by the ''snow plough'' type for the 10-100 ns of high-current accelerator pulse duration are elucidated

Preventing Prescription Drug Abuse in Adolescence: A Collaborative Approach

Science.gov (United States)

Jones, Beth A.; Fullwood, Harry; Hawthorn, Melissa

2012-01-01

With the growing awareness of adolescent prescription drug abuse, communities and schools are beginning to explore prevention and intervention strategies which are appropriate for their youth. This article provides a framework for developing a collaborative approach to prescription drug abuse prevention--called the Prevention Awareness Team--that…

Effects of Spatial Gradients on Electron Runaway Acceleration

Science.gov (United States)

MacNeice, Peter; Ljepojevic, N. N.

1996-01-01

The runaway process is known to accelerate electrons in many laboratory plasmas and has been suggested as an acceleration mechanism in some astrophysical plasmas, including solar flares. Current calculations of the electron velocity distributions resulting from the runaway process are greatly restricted because they impose spatial homogeneity on the distribution. We have computed runaway distributions which include consistent development of spatial gradients in the energetic tail. Our solution for the electron velocity distribution is presented as a function of distance along a finite length acceleration region, and is compared with the equivalent distribution for the infinitely long homogenous system (i.e., no spatial gradients), as considered in the existing literature. All these results are for the weak field regime. We also discuss the severe restrictiveness of this weak field assumption.

Simulation of long-term dynamic behavior of runaway electrons

International Nuclear Information System (INIS)

Wang Yulei; Liu Jian; Zhang Ruili; He Yang

2015-01-01

The secular dynamics of runaway electrons in Tokamak electromagnetic field is studied. The radiation effect is added into a relativistic volume-preserving algorithm to gain long-term stability of calculation. The results shows that the method we used is able to reveal the behavior of a runaway electron in configuration space. (author)

Prevention and Intervention of Depression in Asian-American Adolescents

Science.gov (United States)

Dieu, Kim

2016-01-01

Depression is one of the most common psychological disorders experienced by adolescents. Research has shown depression rates are higher in Asian-American adolescents when compared to their European-American counterparts. This paper will investigate possible programs for preventing and responding to Asian-American youths' depression through a…

Runaway-electron-materials interaction studies

International Nuclear Information System (INIS)

Bolt, H.; Miyahara, A.

1990-03-01

During the operation of magnetic fusion devices it has been frequently observed that runaway electrons can cause severe damage to plasma facing components. The energy of the runaway electrons could possibly reach several 100 MeV in a next generation device with an energy content in the plasma in the order of 100 MJ. In this study effects of high energy electron - materials interaction were determined by laboratory experiments using particle beam facilities, i.e. the Electron Linear Accelerator of the Institute of Scientific and Industrial Research of Osaka University and the 10 MW Neutral Beam Injection Test Stand of the National Institute for Fusion Science. The experiments and further analyses lead to a first assessment of the damage thresholds of plasma facing materials and components under runaway electron impact. It was found that metals (stainless steel, molybdenum, tungsten) showed grain growth, crack formation and/or melting already below the threshold for crack initiation on graphite (14-33 MJ/m 2 ). Strong erosion of carbon materials would occur above 100 MJ/m 2 . Damage to metal coolant channels can occur already below an energy deposition of 100 MJ/m 2 . The energy deposited in the metal coolant channels depends on the thickness of the plasma facing carbon material D, with the shielding efficiency S of carbon approximately as S∼D 1.15 . (author) 304 refs. 12 tabs. 59 figs

Post-retrieval extinction in adolescence prevents return of juvenile fear

Science.gov (United States)

Jones, Carolyn E.

2016-01-01

Traumatic experiences early in life can contribute to the development of mood and anxiety disorders that manifest during adolescence and young adulthood. In young rats exposed to acute fear or stress, alterations in neural development can lead to enduring behavioral abnormalities. Here, we used a modified extinction intervention (retrieval+extinction) during late adolescence (post-natal day 45 [p45]), in rats, to target auditory Pavlovian fear associations acquired as juveniles (p17 and p25). The effects of adolescent intervention were examined by assessing freezing as adults during both fear reacquisition and social transmission of fear from a cagemate. Rats underwent testing or training at three time points across development: juvenile (p17 or p25), adolescent (p45), and adult (p100). Retrieval+extinction during late adolescence prevented social reinstatement and recovery over time of fears initially acquired as juveniles (p17 and p25, respectively). Adolescence was the only time point tested here where retrieval+extinction prevented fear recall of associations acquired 20+ days earlier. PMID:27634147

An Adult Communication Skills Program to Prevent Adolescent Smoking.

Science.gov (United States)

Worden, John K.; And Others

1987-01-01

Conducted communication skills workshops to prevent cigarette smoking among adolescents by teaching adults how to help young people make responsible decisions and resist peer influences. One year later, 66% reported use of skills five or more times in the previous month, and significantly fewer adolescents in the high workshop intensity area…

Run-away electrons in relativistic spin (1) /(2) quantum electrodynamics

International Nuclear Information System (INIS)

Low, F.E.

1998-01-01

The existence of run-away solutions in classical and non-relativistic quantum electrodynamics is reviewed. It is shown that the less singular high energy behavior of relativistic spin (1) /(2) quantum electrodynamics precludes an analogous behavior in that theory. However, a Landau-like anomalous pole in the photon propagation function or in the electron-massive photon forward scattering amplitude would generate a new run-away, characterized by an energy scale ω∼m e thinspexp(1/α). This contrasts with the energy scale ω∼m e /α associated with the classical and non-relativistic quantum run-aways. copyright 1998 Academic Press, Inc

Theory of Planned Behavior in School-Based Adolescent Problem Gambling Prevention: A Conceptual Framework.

Science.gov (United States)

St-Pierre, Renée A; Temcheff, Caroline E; Derevensky, Jeffrey L; Gupta, Rina

2015-12-01

Given its serious implications for psychological and socio-emotional health, the prevention of problem gambling among adolescents is increasingly acknowledged as an area requiring attention. The theory of planned behavior (TPB) is a well-established model of behavior change that has been studied in the development and evaluation of primary preventive interventions aimed at modifying cognitions and behavior. However, the utility of the TPB has yet to be explored as a framework for the development of adolescent problem gambling prevention initiatives. This paper first examines the existing empirical literature addressing the effectiveness of school-based primary prevention programs for adolescent gambling. Given the limitations of existing programs, we then present a conceptual framework for the integration of the TPB in the development of effective problem gambling preventive interventions. The paper describes the TPB, demonstrates how the framework has been applied to gambling behavior, and reviews the strengths and limitations of the model for the design of primary prevention initiatives targeting adolescent risk and addictive behaviors, including adolescent gambling.

The runaway greenhouse: implications for future climate change, geoengineering and planetary atmospheres.

Science.gov (United States)

Goldblatt, Colin; Watson, Andrew J

2012-09-13

The ultimate climate emergency is a 'runaway greenhouse': a hot and water-vapour-rich atmosphere limits the emission of thermal radiation to space, causing runaway warming. Warming ceases only after the surface reaches approximately 1400 K and emits radiation in the near-infrared, where water is not a good greenhouse gas. This would evaporate the entire ocean and exterminate all planetary life. Venus experienced a runaway greenhouse in the past, and we expect that the Earth will in around 2 billion years as solar luminosity increases. But could we bring on such a catastrophe prematurely, by our current climate-altering activities? Here, we review what is known about the runaway greenhouse to answer this question, describing the various limits on outgoing radiation and how climate will evolve between these. The good news is that almost all lines of evidence lead us to believe that is unlikely to be possible, even in principle, to trigger full a runaway greenhouse by addition of non-condensible greenhouse gases such as carbon dioxide to the atmosphere. However, our understanding of the dynamics, thermodynamics, radiative transfer and cloud physics of hot and steamy atmospheres is weak. We cannot therefore completely rule out the possibility that human actions might cause a transition, if not to full runaway, then at least to a much warmer climate state than the present one. High climate sensitivity might provide a warning. If we, or more likely our remote descendants, are threatened with a runaway greenhouse, then geoengineering to reflect sunlight might be life's only hope. Injecting reflective aerosols into the stratosphere would be too short-lived, and even sunshades in space might require excessive maintenance. In the distant future, modifying Earth's orbit might provide a sustainable solution. The runaway greenhouse also remains relevant in planetary sciences and astrobiology: as extrasolar planets smaller and nearer to their stars are detected, some will be in

A 3D thermal runaway propagation model for a large format lithium ion battery module

International Nuclear Information System (INIS)

Feng, Xuning; Lu, Languang; Ouyang, Minggao; Li, Jiangqiu; He, Xiangming

2016-01-01

In this paper, a 3D thermal runaway (TR) propagation model is built for a large format lithium ion battery module. The 3D TR propagation model is built based on the energy balance equation. Empirical equations are utilized to simplify the calculation of the chemical kinetics for TR, whereas equivalent thermal resistant layer is employed to simplify the heat transfer through the thin thermal layer. The 3D TR propagation model is validated by experiment and can provide beneficial discussions on the mechanisms of TR propagation. According to the modeling analysis of the 3D model, the TR propagation can be delayed or prevented through: 1) increasing the TR triggering temperature; 2) reducing the total electric energy released during TR; 3) enhancing the heat dissipation level; 4) adding extra thermal resistant layer between adjacent batteries. The TR propagation is successfully prevented in the model and validated by experiment. The model with 3D temperature distribution provides a beneficial tool for researchers to study the TR propagation mechanisms and for engineers to design a safer battery pack. - Highlights: • A 3D thermal runaway (TR) propagation model for Li-ion battery pack is built. • The 3D TR propagation model can fit experimental results well. • Temperature distributions during TR propagation are presented using the 3D model. • Modeling analysis provides solutions for the prevention of TR propagation. • Quantified solutions to prevent TR propagation in battery pack are discussed.

Determination of the core temperature of a Li-ion cell during thermal runaway

Science.gov (United States)

Parhizi, M.; Ahmed, M. B.; Jain, A.

2017-12-01

Safety and performance of Li-ion cells is severely affected by thermal runaway where exothermic processes within the cell cause uncontrolled temperature rise, eventually leading to catastrophic failure. Most past experimental papers on thermal runaway only report surface temperature measurement, while the core temperature of the cell remains largely unknown. This paper presents an experimentally validated method based on thermal conduction analysis to determine the core temperature of a Li-ion cell during thermal runaway using surface temperature and chemical kinetics data. Experiments conducted on a thermal test cell show that core temperature computed using this method is in good agreement with independent thermocouple-based measurements in a wide range of experimental conditions. The validated method is used to predict core temperature as a function of time for several previously reported thermal runaway tests. In each case, the predicted peak core temperature is found to be several hundreds of degrees Celsius higher than the measured surface temperature. This shows that surface temperature alone is not sufficient for thermally characterizing the cell during thermal runaway. Besides providing key insights into the fundamental nature of thermal runaway, the ability to determine the core temperature shown here may lead to practical tools for characterizing and mitigating thermal runaway.

Thermal effects of runaway electrons in an armoured divertor

International Nuclear Information System (INIS)

Stad, R.C.L. van der.

1993-12-01

This report describes the results of a numerical thermal analysis of the heat deposition of runaway electrons accompanying plasma disruptions in a armoured divertor. The divertor concepts studied are carbon on molybdenum and beryllium on copper. The conclusion is that the runaway electrons can cause melting of the armour as well as melting of the structure and can damage the divertor severely. (orig.)

Kinetic modelling of runaway electron avalanches in tokamak plasmas.

Czech Academy of Sciences Publication Activity Database

Nilsson, E.; Decker, J.; Peysson, Y.; Granetz, R.S.; Saint-Laurent, F.; Vlainic, Milos

2015-01-01

Roč. 57, č. 9 (2015), č. článku 095006. ISSN 0741-3335 EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : plasma physics * runaway electrons * knock-on collisions * tokamak * Fokker-Planck * runaway avalanches Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015

Mitigation of current quench by runaway electrons in LHCD discharges in the HT-7 tokamak

International Nuclear Information System (INIS)

Lu, H.W.; Hu, L.Q.; Lin, S.Y.; Zhong, G.Q.

2009-01-01

Production of runaway electrons during a major disruption has been observed in HT-7 Tokamak. The runaway current plateaus, which can carry part of the pre-disruptive current, are observed in lower-hybrid current drive (LHCD) limiter discharges. It is found that the runaway current can mitigate the disruptions effectively. Detailed observations are presented on the runaway electrons generated following disruptions in the HT-7 tokamak with carbon limited discharges. The results indicate that the magnetic oscillations play an important role in the activity of runaway electrons in disruption. (author)

Evidence-based obesity prevention in childhood and adolescence: critique of recent etiological studies, preventive interventions, and policies.

Science.gov (United States)

Reilly, John J

2012-07-01

Prevention of obesity in childhood and adolescence remains a worthwhile and realistic goal, but preventive efforts have been beset by a number of problems, which are the subject of this review. The review draws on recent systematic reviews and evidence appraisals and has a United Kingdom (UK) perspective because there is a rich evidence base in the United Kingdom that may be helpful to obesity prevention researchers elsewhere. Recent evidence of a leveling off in child and adolescent obesity prevalence in some Western nations should not encourage the belief that the obesity prevention problem has been solved, although a better understanding of recent secular trends might be helpful for prevention strategy in future. An adequate body of evidence provides behavioral targets of preventive interventions, and there are frameworks for prioritizing these targets logically and models for translating them into generalizable interventions with a wide reach (e.g., school-based prevention interventions such as Planet Health). An improved understanding of the "energy gap" that children and adolescents experience would be helpful to the design of preventive interventions and to their tailoring to particular groups. In the United Kingdom, some recent etiological evidence has been taken as indicative of the need for paradigm shifts in obesity prevention, but this evidence from single studies has not been replicated, and paradigm shifts probably occur only rarely. Ensuring that the evidence base on etiology and prevention influences policy effectively remains one of the greatest challenges for childhood obesity researchers.

Control of runaway electron secondary generation by changing Z(eff)

NARCIS (Netherlands)

Pankratov, I. M.; R. Jaspers,; Finken, K.H.; Entrop, I.; Mank, G.

1998-01-01

The effect of Z(eff) on the runaway generation process by close collisions has been studied experimentally in the TEXTOR-94 tokamak in ohmic low density discharges. It is shown that the effective avalanching time increases with increasing Z(eff). This opens the possibility of controlling the runaway

Runaway transient simulation of a model Kaplan turbine

Energy Technology Data Exchange (ETDEWEB)

Liu, S; Liu, D; Wu, Y [State Key Laboratory of Hydroscience and Engineering, Department of Thermal Eng., Tsinghua University, Beijing, 100084 (China); Zhou, D [Water Conservancy and Hydropower Eng., Hohai University, Nanjing. 210098 (China); Nishi, M, E-mail: liushuhong@tsinghua.edu.c [Kyushu Inst. Tech. Senior Academy, Kitakyushu, 804-8550 (Japan)

2010-08-15

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-{epsilon} turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Runaway transient simulation of a model Kaplan turbine

Science.gov (United States)

Liu, S.; Zhou, D.; Liu, D.; Wu, Y.; Nishi, M.

2010-08-01

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-epsilon turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Runaway transient simulation of a model Kaplan turbine

International Nuclear Information System (INIS)

Liu, S; Liu, D; Wu, Y; Zhou, D; Nishi, M

2010-01-01

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-ε turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Running away experience and psychoactive substance use among adolescents in Taiwan: multi-city street outreach survey.

Science.gov (United States)

Wang, Shi-Heng; Chen, Wen-Chun; Lew-Ting, Chih-Yin; Chen, Chuan-Yu; Chen, Wei J

2010-01-20

This study aimed to examine: 1) the relationship between being a runaway and the time since the first absconding event and adolescent substance use; 2) whether different kinds of psychoactive substances have a different temporal relationship to the first absconding event; and 3) whether the various reasons for the first absconding event are associated with different risks of substance use. Participants were drawn from the 2004-2006 nationwide outreach programs across 26 cities/towns in Taiwan. A total of 17,133 participants, age 12-18 years, who completed an anonymous questionnaire on their experience of running away and substances use and who were now living with their families, were included in the analysis. The lifetime risk of tobacco, alcohol, betel nut, and illegal drug/inhalant use increased steadily from adolescents who had experienced a trial runaway episode (one time lasting or= 2 times or lasting > 1 day), when compared to those who had never ran away. Adolescents who had their first running away experience > 6 months previously had a greater risk of betel nut or illegal drug/inhalant use over the past 6-months than those with a similar experience within the last 6 months. Both alcohol and tobacco use were most frequently initiated before the first running away, whereas both betel nut and illegal drug/inhalant use were most frequently initiated after this event. When adolescents who were fleeing an unsatisfactory home life were compared to those who ran away for excitement, the risk of alcohol use was similar but the former tended to have a higher risk of tobacco, betel nut, and illegal drug/inhalant use. More significant running away and a longer time since the first absconding experience were associated with more advanced substance involvement among adolescents now living in a family setting. Once adolescents had left home, they developed additional psychoactive substance problems, regardless of their reasons for running away. These findings have

Preventive strategies in child and adolescent psychiatry

Directory of Open Access Journals (Sweden)

Rajesh Sagar

2017-01-01

Full Text Available Childhood and adolescence are periods of growth and development that are critical to the formation of adult personality and psychopathology. Moreover, childhood psychopathology may differ significantly in presentation and risk factors from those seen among adults and may require different preventive strategies. Service-related characteristics such as the shortage of trained child and adolescent mental health professionals also demand that the focus should shift from resource-intensive treatment interventions, toward preventive measures that can be delivered at lower cost in terms of workforce, money, and time; and can lead to improved outcomes for a wide variety of conditions. Preventive strategies that have been implemented in this population have mostly included both preventive measures (aiming at reducing the prevalence of risk factors and promotive components (aimed at increasing resilience and positive mental health characteristics, usually in combination. Interventions have been shown to be most effective when they are targeted at underlying latent structures that predict risk; they are also more effective when delivered over a prolonged period. Interventions must also be formulated such that they are developmentally appropriate, and with clearly stated outcome parameters for evaluation. A few example interventions that have made use of these strategies are discussed in the course of this article.

X-ray study of bow shocks in runaway stars

Science.gov (United States)

De Becker, M.; del Valle, M. V.; Romero, G. E.; Peri, C. S.; Benaglia, P.

2017-11-01

Massive runaway stars produce bow shocks through the interaction of their winds with the interstellar medium, with the prospect for particle acceleration by the shocks. These objects are consequently candidates for non-thermal emission. Our aim is to investigate the X-ray emission from these sources. We observed with XMM-Newton a sample of five bow shock runaways, which constitutes a significant improvement of the sample of bow shock runaways studied in X-rays so far. A careful analysis of the data did not reveal any X-ray emission related to the bow shocks. However, X-ray emission from the stars is detected, in agreement with the expected thermal emission from stellar winds. On the basis of background measurements we derive conservative upper limits between 0.3 and 10 keV on the bow shocks emission. Using a simple radiation model, these limits together with radio upper limits allow us to constrain some of the main physical quantities involved in the non-thermal emission processes, such as the magnetic field strength and the amount of incident infrared photons. The reasons likely responsible for the non-detection of non-thermal radiation are discussed. Finally, using energy budget arguments, we investigate the detectability of inverse Compton X-rays in a more extended sample of catalogued runaway star bow shocks. From our analysis we conclude that a clear identification of non-thermal X-rays from massive runaway bow shocks requires one order of magnitude (or higher) sensitivity improvement with respect to present observatories.

Destabilization of the electron Bernstein modes by runaway electrons

International Nuclear Information System (INIS)

Hitchcock, D.A.; Mahajan, S.M.

1982-01-01

It is shown that the electromagnetic finite k/sub parallel/ electron Bernstein mode can be destabilized by the runaway electron distribution which results from the quasilinear action of the magnetized plasma oscillation. This mechanism is shown to yield growth rates of the order of 10 8 sec -1 and is suggested as a mechanism for the enchanced cyclotron harmonic emission in the presence of runaway electrons

Sawtooth-induced loss of runaway electrons in tokamaks

International Nuclear Information System (INIS)

Yan Longwen; Shi Bingren; Jiao Yiming

2001-01-01

A model based on banana orbit loss has been proposed to explain the sawtooth effect on the loss of the runaway electrons in tokamaks. Circulating runaway electrons can be transferred into the trapped ones due to magnetic perturbation during sawtooth crashes, then they are repelled to the limiter via toroidal precession drift with a time delay. This model may also clarify the hard X-ray oscillations correlated with the m = 2 mode and the hard X-ray bursts during outer disruptions

Application of Statistical Potential Techniques to Runaway Transport Studies

International Nuclear Information System (INIS)

Eguilior, S.; Castejon, F.; Parrondo, J. M.

2001-01-01

A method is presented for computing runaway production rate based on techniques of noise-activated escape in a potential is presented in this work. A generalised potential in 2D momentum space is obtained from the deterministic or drift terms of Langevin equations. The diffusive or stochastic terms that arise directly from the stochastic nature of collisions, play the role of the noise that activates barrier crossings. The runaway electron source is given by the escape rate in such a potential which is obtained from an Arrenius-like relation. Runaway electrons are those skip the potential barrier due to the effect of stochastic collisions. In terms of computation time, this method allows one to quickly obtain the source term for a runway electron transport code.(Author) 11 refs

Eating habits, knowledge about cancer prevention and the HPLP scale in Turkish adolescents.

Science.gov (United States)

Can, Hafize Ozturk; Ceber, Esin; Sogukpinar, Neriman; Saydam, Birsen Karaca; Otles, Semih; Ozenturk, Gulsun

2008-01-01

Nutritional status and healthy lifestyle are important factors not only in cancer etiology but also for prevention efforts. A good nutritional status contributes to a healthy life with high economic, social and cultural level. Unhealthy eating habits are part of risky behavior seen from adolescence. The present study was therefore carried out to determine eating habits, level of knowledge about cancer prevention and behavior of a group of adolescents. Data were collected using questionnaire covering eating habits and knowledge of adolescents on prevention from cancer, and special scale (HPLP) to determine the related behavior. Three hundred sixty six of 390 students volunteered for study. Eating habits and the level of cancer prevention knowledge were similar for both genders, except for the exercise issue. The mean total points of adolescents in the Health Promotion Behavior and Subscales was 113,63. While spiritual growth had the highest score in HPLP subscale, exercise had a minimal score. Exercise was the only HPLP subscale with a statistically significant difference between male and female genders. Although they have some information, the adolescents surveyed did not have preventive skills relative to their practical life. In general in order to ensure cancer prevention and a healthy life style social, cultural and sportive activities should be encouraged and educational programmes supporting these goals should be designed and applied for all stages of life, starting in early childhood.

A Systematic Review of Apps using Mobile Criteria for Adolescent Pregnancy Prevention (mCAPP).

Science.gov (United States)

Chen, Elizabeth; Mangone, Emily Rose

2016-11-10

Adolescents in the United States and globally represent a high-risk population for unintended pregnancy, which leads to high social, economic, and health costs. Access to smartphone apps is rapidly increasing among youth, but little is known about the strategies that apps employ to prevent pregnancy among adolescents and young adults. Further, there are no guidelines on best practices for adolescent and young adult pregnancy prevention through mobile apps. This review developed a preliminary evaluation framework for the assessment of mobile apps for adolescent and young adult pregnancy prevention and used this framework to assess available apps in the Apple App Store and Google Play that targeted adolescents and young adults with family planning and pregnancy prevention support. We developed an assessment rubric called Mobile Criteria for Adolescent Pregnancy Prevention (mCAPP) for data extraction using evidence-based and promising best practices from the literature. mCAPP comprises 4 domains: (1) app characteristics, (2) user interface features, (3) adolescent pregnancy prevention best practices, and (4) general sexual and reproductive health (SRH) features. For inclusion in the review, apps that advertised pregnancy prevention services and explicitly mentioned youth, were in English, and were free were systematically identified in the Apple App Store and Google Play in 2015. Screening, data extraction, and 4 interrater reliability checks were conducted by 2 reviewers. Each app was assessed for 92 facets of the mCAPP checklist. Our search returned 4043 app descriptions in the Apple App Store (462) and Google Play (3581). After screening for inclusion criteria, 22 unique apps were included in our analysis. Included apps targeted teens in primarily developed countries, and the most common user interface features were clinic and health service locators. While app strengths included provision of SRH education, description of modern contraceptives, and some use of

45 CFR 1351.17 - How is application made for a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false How is application made for a Runaway and Homeless... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.17 How is application made for a Runaway and Homeless...

45 CFR 1351.15 - What costs are supportable under a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false What costs are supportable under a Runaway and... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.15 What costs are supportable under a Runaway and Homeless...

Observation of the Avalanche of Runaway Electrons in Air in a Strong Electric Field

Science.gov (United States)

Gurevich, A. V.; Mesyats, G. A.; Zybin, K. P.; Yalandin, M. I.; Reutova, A. G.; Shpak, V. G.; Shunailov, S. A.

2012-08-01

The generation of an avalanche of runaway electrons is demonstrated for the first time in a laboratory experiment. Two flows of runaway electrons are formed sequentially in an extended air discharge gap at the stage of delay of a pulsed breakdown. The first, picosecond, runaway electron flow is emitted in the cathode region where the field is enhanced. Being accelerated in the gap, this beam generates electrons due to impact ionization. These secondary electrons form a delayed avalanche of runaway electrons if the field is strong enough. The properties of the avalanche correspond to the existing notions about the runaway breakdown in air. The measured current of the avalanche exceeds up to an order the current of the initiating electron beam.

45 CFR 1351.10 - What is the purpose of the Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false What is the purpose of the Runaway and Homeless... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.10 What is the purpose of the Runaway and Homeless Youth...

On the effect of electron's runaway in partially ionized hydrogen semiclassical nonideal plasma

International Nuclear Information System (INIS)

Turekhanova, K.M.

2011-01-01

Complete text of publication follows. The effect of runaway electrons occurs frequently in tokamak plasmas. The majority of experiments in tokamak research have been devoted to the study of confinement properties of runaway electrons. Runaway electrons are reason of various destroying untolarance in tokamak plasmas. At high plasma density, when the critical energy is comparable with the rest energy the multiplication of runaway electrons accelerate at the sacrifice of increase of plasma density. The plasma conductivity is determined by electrons with energy several times higher than the thermal one and does not practically depend on slower electrons distribution. It is important to analyze the probability of runaway electrons at investigation of physical properties of nonideal plasmas under external electric field and running numerical simulations of their. The present paper is devoted to the investigation of effect of runaway electrons in partially ionized hydrogen dense plasma using the effective potentials of particle's interaction. At the investigation of composition of plasma we used the Saha equation with corrections to nonideality (lowering of ionization potentials). The Saha equation was solved for obtaining of plasma ionization stages at the different number density and temperature. As well, when take into account quantum-mechanical diffraction and screening effects, whereas free path of electrons increases with increase of plasma coupling parameter. The condition for appearance of runaway electrons in semiclassical partially ionized plasma is more favorable in regime of dense plasma. In summary it means that the probability of runaway electron in dense plasma is more than the same in rarified plasma that is possibly connected with formation of some ordered structures in dense plasma.

Personalized Biobehavioral HIV Prevention for Women and Adolescent Girls.

Science.gov (United States)

Brawner, Bridgette M; Teitelman, Anne M; Bevilacqua, Amanda W; Jemmott, Loretta Sweet

2013-09-01

Women and adolescent girls bear a significant burden of the global HIV pandemic. Both behavioral and biomedical prevention approaches have been shown to be effective. In order to foster the most effective combination HIV-prevention approaches for women and girls, it is imperative to understand the unique biological, social, and structural considerations that increase vulnerability to acquiring HIV within this population. The purpose of this article is to propose novel ideas for personalized biobehavioral HIV prevention for women and adolescent girls. The central argument is that we must transcend unilevel solutions for HIV prevention toward comprehensive, multilevel combination HIV prevention packages to actualize personalized biobehavioral HIV prevention. Our hope is to foster transnational dialogue among researchers, practitioners, educators, and policy makers toward the actualization of the proposed recommendations. We present a commentary organized to review biological, social, and structural factors that increase vulnerability to HIV acquisition among women and adolescent girls. The overview is followed by recommendations to curb HIV rates in the target population in a sustainable manner. The physiology of the lower female reproductive system biologically increases HIV risk among women and girls. Social (eg, intimate partner violence) and structural (eg, gender inequality) factors exacerbate this risk by increasing the likelihood of viral exposure. Our recommendations for personalized biobehavioral HIV prevention are to (1) create innovative mechanisms for personalized HIV risk-reduction assessments; (2) develop mathematical models of local epidemics; (3) prepare personalized, evidence-based combination HIV risk-reduction packages; (4) structure gender equity into society; and (5) eliminate violence (both physical and structural) against women and girls. Generalized programs and interventions may not have universal, transnational, and crosscultural

Adolescent Self-Consent for Biomedical Human Immunodeficiency Virus Prevention Research.

Science.gov (United States)

Gilbert, Amy Lewis; Knopf, Amelia S; Fortenberry, J Dennis; Hosek, Sybil G; Kapogiannis, Bill G; Zimet, Gregory D

2015-07-01

The Adolescent Medicine Trials Network Protocol 113 (ATN113) is an open-label, multisite demonstration project and Phase II safety study of human immunodeficiency virus (HIV) preexposure prophylaxis with 15- to 17-year-old young men who have sex with men that requires adolescent consent for participation. The purpose of this study was to examine factors related to the process by which Institutional Review Boards (IRBs) and researchers made decisions regarding whether to approve and implement ATN113 so as to inform future biomedical HIV prevention research with high-risk adolescent populations. Participants included 17 researchers at 13 sites in 12 states considering ATN113 implementation. Qualitative descriptive methods were used. Data sources included interviews and documents generated during the initiation process. A common process for initiating ATN113 emerged, and informants described how they identified and addressed practical, ethical, and legal challenges that arose. Informants described the process as responding to the protocol, preparing for IRB submission, abstaining from or proceeding with submission, responding to IRB concerns, and reacting to the outcomes. A complex array of factors impacting approval and implementation were identified, and ATN113 was ultimately implemented in seven of 13 sites. Informants also reflected on lessons learned that may help inform future biomedical HIV prevention research with high-risk adolescent populations. The results illustrate factors for consideration in determining whether to implement such trials, demonstrate that such protocols have the potential to be approved, and highlight a need for clearer standards regarding biomedical HIV prevention research with high-risk adolescent populations. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Evidence-Based Obesity Prevention in Childhood and Adolescence: Critique of Recent Etiological Studies, Preventive Interventions, and Policies123

Science.gov (United States)

Reilly, John J.

2012-01-01

Prevention of obesity in childhood and adolescence remains a worthwhile and realistic goal, but preventive efforts have been beset by a number of problems, which are the subject of this review. The review draws on recent systematic reviews and evidence appraisals and has a United Kingdom (UK) perspective because there is a rich evidence base in the United Kingdom that may be helpful to obesity prevention researchers elsewhere. Recent evidence of a leveling off in child and adolescent obesity prevalence in some Western nations should not encourage the belief that the obesity prevention problem has been solved, although a better understanding of recent secular trends might be helpful for prevention strategy in future. An adequate body of evidence provides behavioral targets of preventive interventions, and there are frameworks for prioritizing these targets logically and models for translating them into generalizable interventions with a wide reach (e.g., school-based prevention interventions such as Planet Health). An improved understanding of the “energy gap” that children and adolescents experience would be helpful to the design of preventive interventions and to their tailoring to particular groups. In the United Kingdom, some recent etiological evidence has been taken as indicative of the need for paradigm shifts in obesity prevention, but this evidence from single studies has not been replicated, and paradigm shifts probably occur only rarely. Ensuring that the evidence base on etiology and prevention influences policy effectively remains one of the greatest challenges for childhood obesity researchers. PMID:22798005

Generation of runaway electron beams in high-pressure nitrogen

Science.gov (United States)

Tarasenko, V. F.; Burachenko, A. G.; Baksht, E. Kh

2017-07-01

In this paper the results of experimental studies of the amplitude-temporal characteristics of a runaway electron beam, as well as breakdown voltage in nitrogen are presented. The voltage pulses with the amplitude in incident wave ≈120 kV and the rise time of ≈0.3 ns was used. The supershort avalanche electron beam (SAEB) was detected by a collector behind the flat anode. The amplitude-time characteristics of the voltage and SAEB current were studied with subnanosecond time resolution. The maximum pressure at which a SAEB is detectable by collector was ∼1 MPa. This pressure increases with decreasing the voltage rise time. The waveforms of the discharge and runaway electron beam currents was synchronized with the voltage pulses. The mechanism of the runaway electron generation in atmospheric-pressure gases is analyzed on the basis of the obtained experimental data.

Runaway beam studies during disruptions at JET-ILW

International Nuclear Information System (INIS)

Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Brezinsek, S.; Decker, J.; Devaux, S.; Vries, P. de; Fil, A.

2015-01-01

Highlights: • Runaway electrons (RE) have been obtained at JET-ILW using massive argon injection. • The runaway electron domain entry points are similar between JET-C and JET-ILW. • Inside the runaway electron domain, higher RE currents are observed with JET-ILW. • RE impact has been observed without material melting up to 100 kA RE current. • Heat deposition of 2 ± 1 mm is confirmed by measurements and simulations. - Abstract: Runaway electrons (RE) during disruptions are a concern for future tokamaks including ITER with its metallic wall. Although RE are rare in spontaneous disruptions with the JET ITER-like Wall (JET-ILW), RE beams up to 380 kA were obtained using massive injection (MGI) of argon in JET-ILW divertor discharges. Entry points into the RE domain defined by operational parameters (toroidal field, argon fraction in MGI) are unchanged but higher RE currents have been obtained inside the JET-ILW MGI-generated RE domain when compared to JET-C. This might be due to the influence of the metallic wall on the current quench plasma. Temperatures of 900 °C have been observed following RE impacts on beryllium tiles. Heat deposition depth of ∼2 mm has to be assumed to match the tile cooling time. 3D simulations of the RE energy deposition using the ENDEP/MEMOS codes show that material melting is unlikely with 100 kA RE beams

Runaway beam studies during disruptions at JET-ILW

Energy Technology Data Exchange (ETDEWEB)

Reux, C., E-mail: cedric.reux@cea.fr [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Plyusnin, V. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Instituto de Plasmas e Fuso Nuclear, Instituto Superior Tcnico, Universidade de Lisboa, Lisboa (Portugal); Alper, B. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Alves, D. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Instituto de Plasmas e Fuso Nuclear, Instituto Superior Tcnico, Universidade de Lisboa, Lisboa (Portugal); Bazylev, B. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Institut für Hochleistungsimpuls und Mikrowellentechnik, Karlsruhe Institute of Technology, Campus Nord, 76021 Karlsruhe (Germany); Belonohy, E. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); EFDA-CSU, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Brezinsek, S. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Forschungszentrum Jülich GmbH, Institut für Energie-und Klimaforschung-Plasmaphysik, 52425 Jülich (Germany); Decker, J. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Devaux, S. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CCFE, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Vries, P. de [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance (France); Fil, A. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); and others

2015-08-15

Highlights: • Runaway electrons (RE) have been obtained at JET-ILW using massive argon injection. • The runaway electron domain entry points are similar between JET-C and JET-ILW. • Inside the runaway electron domain, higher RE currents are observed with JET-ILW. • RE impact has been observed without material melting up to 100 kA RE current. • Heat deposition of 2 ± 1 mm is confirmed by measurements and simulations. - Abstract: Runaway electrons (RE) during disruptions are a concern for future tokamaks including ITER with its metallic wall. Although RE are rare in spontaneous disruptions with the JET ITER-like Wall (JET-ILW), RE beams up to 380 kA were obtained using massive injection (MGI) of argon in JET-ILW divertor discharges. Entry points into the RE domain defined by operational parameters (toroidal field, argon fraction in MGI) are unchanged but higher RE currents have been obtained inside the JET-ILW MGI-generated RE domain when compared to JET-C. This might be due to the influence of the metallic wall on the current quench plasma. Temperatures of 900 °C have been observed following RE impacts on beryllium tiles. Heat deposition depth of ∼2 mm has to be assumed to match the tile cooling time. 3D simulations of the RE energy deposition using the ENDEP/MEMOS codes show that material melting is unlikely with 100 kA RE beams.

The production and confinement of runaway electrons with impurity ''killer'' pellets in DIII-D

International Nuclear Information System (INIS)

Evans, T.E.; Taylor, P.L.; Whyte, D.G.

1998-12-01

Prompt runaway electron bursts, generated by rapidly cooling DIII-D plasmas with argon killer pellets, are used to test a recent knock-on avalanche theory describing the growth of multi-MeV runaway electron currents during disruptions in tokamaks. Runaway current amplitudes, observed during some but not all DIII-D current quenches, are consistent with growth rates predicted by the theory assuming a pre-current quench runaway electron density of approximately 10 15 m -3 . Argon killer pellet modeling yields runaway densities of between 10 15 --10 16 m -3 in these discharges. Although knock-on avalanching appears to agree rather well with the measurements, relatively small avalanche amplification factors combined with uncertainties in the spatial distribution of pellet mass and cooling rates make it difficult to unambiguously confirm the proposed theory with existing data

45 CFR 1351.20 - What are the additional requirements under a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... Runaway and Homeless Youth Program grant? 1351.20 Section 1351.20 Public Welfare Regulations Relating to... THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND... Runaway and Homeless Youth Program grant? (a) To improve the administration of the Runaway and Homeless...

Updates on adolescent dating and sexual violence prevention and intervention.

Science.gov (United States)

Miller, Elizabeth; Jones, Kelley A; McCauley, Heather L

2018-05-09

Dating and sexual violence victimization are not uncommon in early adolescence and increase in prevalence throughout adolescence into young adulthood with profound health and social consequences. Greater attention to what works in prevention is needed to inform current policies and practices. Adolescent dating violence (ADV) and sexual violence victimization, including cyber dating abuse, are highly prevalent among adolescents. Studies have found sex category differences, with adolescent girls reporting more victimization than boys, particularly sexual violence. Sexual and gender minority youth also experience a higher prevalence of violence victimization than their heterosexual counterparts. Studies on risk factors include examinations of childhood adversities, exposure to sexually explicit material and substance use as well as the role of gender inequitable attitudes on violence perpetration. Recent prevention research includes examining the impact of bystander interventions and transforming gender norms. Recent ADV/ sexual violence research highlights both prevalence and modifiable risk and protective factors that may help reduce such violence. Practitioners caring for youth should consider ADV/ sexual violence when seeing patients (including those struggling with substance use and other behaviours that contribute to poor health) and not simply rely on screening tools to identify those suffering from ADV/ sexual violence.

Fast Thermal Runaway Detection for Lithium-Ion Cells in Large Scale Traction Batteries

Directory of Open Access Journals (Sweden)

Sascha Koch

2018-03-01

Full Text Available Thermal runaway of single cells within a large scale lithium-ion battery is a well-known risk that can lead to critical situations if no counter measures are taken in today’s lithium-ion traction batteries for battery electric vehicles (BEVs, plug-in hybrid electric vehicles (PHEV and hybrid electric vehicles (HEVs. The United Nations have published a draft global technical regulation on electric vehicle safety (GTR EVS describing a safety feature to warn passengers in case of a thermal runaway. Fast and reliable detection of faulty cells undergoing thermal runaway within the lithium-ion battery is therefore a key factor in battery designs for comprehensive passenger safety. A set of various possible sensors has been chosen based on the determined cell thermal runaway impact. These sensors have been tested in different sized battery setups and compared with respect to their ability of fast and reliable thermal runaway detection and their feasibility for traction batteries.

A Comparison of Religious Orientation and General Health in Runaway Girls and Normal Ones

Directory of Open Access Journals (Sweden)

Abolfazl Mohammadbeigi

2016-12-01

Full Text Available Background and Objectives: Due to the negative consequence of girls’ escape, this study was conducted to compare personality, demographic, and religious characteristics of runaway girls and normal ones in Qom city. Methods: In a case control study, 66 single runaway girls and 66 normal girls were selected as experimental group and control group, respectively. Data was culled using interview method, demographic information questionnaire, Allport religious orientation, and general health questionnaires (GHQ. Chi square and independent t-test were applied to analyze final data. Results: Average general health scores were calculated to be 13.9±11 and 9±6.2 in runaway and normal girls, respectively. The score of religious orientation is significantly lower in runaway girls than normal girls (p0.05. Conclusion: Religious orientation was found to be lower in runaway girls than in normal ones. Since runaway girls are subject to physical and sexual abuse, their psychological health is highly vulnerable—the fact which might pave the way for other social abnormalities.

Influence of the angular scattering of electrons on the runaway threshold in air

Science.gov (United States)

Chanrion, O.; Bonaventura, Z.; Bourdon, A.; Neubert, T.

2016-04-01

The runaway electron mechanism is of great importance for the understanding of the generation of x- and gamma rays in atmospheric discharges. In 1991, terrestrial gamma-ray flashes (TGFs) were discovered by the Compton Gamma-Ray Observatory. Those emissions are bremsstrahlung from high energy electrons that run away in electric fields associated with thunderstorms. In this paper, we discuss the runaway threshold definition with a particular interest in the influence of the angular scattering for electron energy close to the threshold. In order to understand the mechanism of runaway, we compare the outcome of different Fokker-Planck and Monte Carlo models with increasing complexity in the description of the scattering. The results show that the inclusion of the stochastic nature of collisions smooths the probability to run away around the threshold. Furthermore, we observe that a significant number of electrons diffuse out of the runaway regime when we take into account the diffusion in angle due to the scattering. Those results suggest using a runaway threshold energy based on the Fokker-Planck model assuming the angular equilibrium that is 1.6 to 1.8 times higher than the one proposed by [1, 2], depending on the magnitude of the ambient electric field. The threshold also is found to be 5 to 26 times higher than the one assuming forward scattering. We give a fitted formula for the threshold field valid over a large range of electric fields. Furthermore, we have shown that the assumption of forward scattering is not valid below 1 MeV where the runaway threshold usually is defined. These results are important for the thermal runaway and the runaway electron avalanche discharge mechanisms suggested to participate in the TGF generation.

CFD research on runaway transient of pumped storage power station caused by pumping power failure

International Nuclear Information System (INIS)

Zhang, L G; Zhou, D Q

2013-01-01

To study runaway transient of pumped storage power station caused by pumping power failure, three dimensional unsteady numerical simulations were executed on geometrical model of the whole flow system. Through numerical calculation, the changeable flow configuration and variation law of some parameters such as unit rotate speed,flow rate and static pressure of measurement points were obtained and compared with experimental data. Numerical results show that runaway speed agrees well with experimental date and its error was 3.7%. The unit undergoes pump condition, brake condition, turbine condition and runaway condition with flow characteristic changing violently. In runaway condition, static pressure in passage pulses very strongly which frequency is related to runaway speed

Relation of the runaway avalanche threshold to momentum space topology

Science.gov (United States)

McDevitt, Christopher J.; Guo, Zehua; Tang, Xian-Zhu

2018-02-01

The underlying physics responsible for the formation of an avalanche instability due to the generation of secondary electrons is studied. A careful examination of the momentum space topology of the runaway electron population is carried out with an eye toward identifying how qualitative changes in the momentum space of the runaway electrons is correlated with the avalanche threshold. It is found that the avalanche threshold is tied to the merger of an O and X point in the momentum space of the primary runaway electron population. Such a change of the momentum space topology is shown to be accurately described by a simple analytic model, thus providing a powerful means of determining the avalanche threshold for a range of model assumptions.

Comparative study of runaway electron diffusion in the rise phase of ...

Indian Academy of Sciences (India)

The behaviour of runaway electrons in the SINP tokamak, which can be operated in a normal edge safety factor () (NQ) discharge configuration as well as in a low (LQ) configuration, was experimentally investigated, during the initial plasma generation phase. An energy analysis of the runaway electron dynamics in ...

Adolescent neurocognitive development, self-regulation, and school-based drug use prevention.

Science.gov (United States)

Pokhrel, Pallav; Herzog, Thaddeus A; Black, David S; Zaman, Adnin; Riggs, Nathaniel R; Sussman, Steve

2013-06-01

Adolescence is marked by several key development-related changes, including neurocognitive changes. Cognitive abilities associated with self-regulation are not fully developed until late adolescence or early adulthood whereas tendencies to take risks and seek thrilling and novel experience seem to increase significantly throughout this phase, resulting in a discrepancy between increased susceptibility to poor regulation and lower ability to exercise self-control. Increased vulnerability to drug use initiation, maintenance, and dependence during adolescence may be explained based on this imbalance in the self-regulation system. In this paper, we highlight the relevance of schools as a setting for delivering adolescent drug use prevention programs that are based on recent findings from neuroscience concerning adolescent brain development. We discuss evidence from school-based as well as laboratory research that suggests that suitable training may improve adolescents' executive brain functions that underlie self-regulation abilities and, as a result, help prevent drug use and abuse. We note that considerable further research is needed in order (1) to determine that self-regulation training has effects at the neurocognitive level and (2) to effectively incorporate self-regulation training based on neuropsychological models into school-based programming.

45 CFR 1351.16 - What costs are not allowable under a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false What costs are not allowable under a Runaway and... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.16 What costs are not allowable under a Runaway and...

77 FR 33223 - Announcement of the Publication of Funding Opportunity Announcements Under the Runaway and...

Science.gov (United States)

2012-06-05

... the Publication of Funding Opportunity Announcements Under the Runaway and Homeless Youth Act AGENCY... Statutory Authority: Runaway and Homeless Youth Act, 42 U.S.C. sections 5701-5752, as amended by the.... Porter, Director, Runaway and Homeless Youth Program, Family and Youth Services Bureau, 1250 Maryland Ave...

Runaway pacemaker: a still existing complication and therapeutic guidelines

DEFF Research Database (Denmark)

Mickley, H; Andersen, C; Nielsen, L H

1989-01-01

Runaway pacemaker is a rare, but still existing potential lethal complication in permanent pacemakers. Within 4 1/2 years, we saw two cases of runaway pacemaker in patients with multiprogrammable, VVI pacemakers (Siemens-Elema, Model 668). In both cases a pacemaker-induced ventricular tachycardia...... pacemaker may be connected to the permanent pacing lead. Thereafter, the lead can be safely cut. As an alternative, a temporary transvenous pacing lead may be established prior to disconnecting the permanent pacing lead....

Awareness of cervical cancer prevention among mothers of adolescent daughters in Korea: qualitative research.

Science.gov (United States)

Kim, Hae Won; Kim, Duck Hee

2015-05-14

Korean adolescent girls are unprepared for cervical cancer prevention due to the lack of a mandatory policy regarding human papilloma virus (HPV) vaccination and school health education regarding cervical cancer. The aim of this study was to determine how aware mothers are about cervical cancer prevention in their adolescent daughters, with a view to developing strategies for expanding primary cervical cancer prevention for adolescent girls through the mothers' involvement. A qualitative design was employed. Nine mothers with adolescent daughters participated in this study and were interviewed using open-ended questions. The themes were extracted by content analysis. A general living area in Seoul, South Korea. The snowball method was used to select mothers. Five themes emerged. In general, the mothers' awareness of cervical cancer was not clear, and they exhibited a lack of awareness of the importance of having a regular Papanicolaou screening test. The mothers recognised that they were role models for their daughters, and realised and accepted the necessity of educating their daughters regarding cervical cancer; however, they perceived barriers related to the prevention of cervical cancer in their daughters. The mothers recommended enforcing sex education in schools and the provision of financial support for HPV vaccination. The mothers' awareness and preparedness with respect to the prevention of cervical cancer in their adolescent daughters were low and inadequate. Mothers should be informed and motivated to play a role in the education of their daughters regarding cervical cancer prevention. Strategies for disseminating information regarding early cervical cancer prevention for adolescent girls are recommended by communicating with both the girls and their mothers and providing them with education regarding cervical cancer prevention. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

Physics of the interaction between runaway electrons and the background plasma of the current quench in tokamak disruptions

Science.gov (United States)

Reux, Cedric

2017-10-01

Runaway electrons are created during disruptions of tokamak plasmas. They can be accelerated in the form of a multi-MA beam at energies up to several 10's of MeV. Prevention or suppression of runaway electrons during disruptions will be essential to ensure a reliable operation of future tokamaks such as ITER. Recent experiments showed that the suppression of an already accelerated beam with massive gas injection was unsuccessful at JET, conversely to smaller tokamaks. This was attributed to a dense, cold background plasma (up to several 1020 m-3 accompanying the runaway beam. The present contribution reports on the latest experimental results obtained at JET showing that some mitigation efficiency can be restored by changing the features of the background plasma. The density, temperature, position of the plasma and the energy of runaways were characterized using a combined analysis of interferometry, soft X-rays, bolometry, magnetics and hard X-rays. It showed that lower density background plasmas were obtained using smaller amounts of gas to trigger the disruption, leading to an improved penetration of the mitigation gas. Based on the observations, a physical model of the creation of the background plasma and its subsequent evolution is proposed. The plasma characteristics during later stages of the disruption are indeed dependent on the way it was initially created. The sustainment of the plasma during the runaway beam phase is then addressed by making a power balance between ohmic heating, power transfer from runaway electrons, radiation and atomic processes. Finally, a model of the interaction of the plasma with the mitigation gas is proposed to explain why massive gas injection of runaway beams works only in specific situations. This aims at pointing out which parameters bear the most importance if this mitigation scheme is to be used on larger devices like ITER. Acknowledgement: This work has been carried out within the framework of the EUROfusion Consortium

Conditions for electron runaway under leader breakdown of long gaps

International Nuclear Information System (INIS)

Ul'yanov, K. N.

2008-01-01

An original hydrodynamic model in which inelastic collisions in the equations of motion and energy balance play a decisive role is developed and applied to simulate electron avalanches in strong electric fields. The mean energy and drift velocity of electrons, as well as the ionization coefficient and electric field in a wide range of mean electron energies, are determined for helium and xenon. A criterion is derived for the runaway of the average electron in discharges with ionization multiplication. It is shown that runaway can take place at any value of E/p, provided that the momentum mean free path exceeds the gap length. The voltage corresponding to electron runaway is found for helium, xenon, and air as a function of the electric field, the electron mean energy, and the parameter pd. Conditions for the formation of a precursor in electronegative gases are analyzed. It is shown that the presence of a precursor with a high electric conductance is necessary for the formation of a new leader step. The voltage and time ranges corresponding to efficient electron runaway and X-ray generation during leader breakdown in air are determined

Comparative study of runaway electron diffusion in the rise phase of ...

Indian Academy of Sciences (India)

Abstract. The behaviour of runaway electrons in the SINP tokamak, which can be operated in a normal edge safety factor (qa) (NQ) discharge configuration as well as in a low qa (LQ) configuration, was experimentally investigated, during the initial plasma generation phase. An energy analysis of the runaway electron ...

45 CFR 1351.11 - Who is eligible to apply for a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Who is eligible to apply for a Runaway and... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.11 Who is eligible to apply for a Runaway and Homeless...

Measurements of Silicon Detector Thermal Runaway

CERN Document Server

Heusch, C A; Moser, H G

1999-01-01

We measured thermal runaway properties of previously irradiated silicon detectors cooled by TPG bars. We simulated their expected behaviour to measure the energy gap in the detector material and to test the validity of various underlying assumptions.

2d axisymmetric "beam-bulk" modelling of the generation of runaway electrons by streamers.

Science.gov (United States)

Chanrion, Olivier; Bonaventura, Zdenek; Bourdon, Anne; Neubert, Torsten

2017-04-01

We present results from a 2d axisymmetric numerical model of streamers based on a "beam-bulk" approach which describes cold electrons with a fluid model and high energy electrons with a particle model. The interest is motivated by the generation of runaway electrons by streamers which may participate in the recently observed TGFs and which challenge the modelling. Runaway electrons are known to be generated from streamers when the electric field in its negative tip is of sufficient magnitude. After overtaking the streamer tip, runaways can affect the streamer propagation ahead and may produce high energy photons through the bremsstrahlung process. In conventional model of streamers, the evolution of the streamer discharge is mostly governed by cold electrons. By including runaway electrons, we model their production, their impact on the discharge propagation and can address their role in TGFs. Results of streamer propagation in leader electric field show that the runaway electrons accelerate the streamers, reduce the electric field in its tip and enlarge its radius by pre-ionizing the gas ahead. We observed that if we increase the electric field, the discharge is getting more diffuse, with a pattern driven by the increase in runaway induced ionisation.

Relativistic runaway breakdown in low-frequency radio

Science.gov (United States)

Füllekrug, Martin; Roussel-Dupré, Robert; Symbalisty, Eugene M. D.; Chanrion, Olivier; Odzimek, Anna; van der Velde, Oscar; Neubert, Torsten

2010-01-01

The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which is characterized by consecutive broadband pulses in the low-frequency radio range from ˜10 to 300 kHz at a distance of ˜800 km. Experimental evidence for the existence of consecutive broadband pulses is provided by low-frequency radio observations of sprite-producing lightning discharges at a distance of ˜550 km. The measured broadband pulses occur ˜4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from ˜50 to 350 kHz, and they exhibit complex waveforms without the typical ionospheric reflection of the first hop sky wave. Two consecutive pulses occur ˜4.5 ms and ˜3 ms after the causative lightning discharge and coincide with the sprite luminosity. It is concluded that relativistic runaway breakdown within the Earth's atmosphere can emit broadband electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.

Numerical analysis on pump turbine runaway points

International Nuclear Information System (INIS)

Guo, L; Liu, J T; Wang, L Q; Jiao, L; Li, Z F

2012-01-01

To research the character of pump turbine runaway points with different guide vane opening, a hydraulic model was established based on a pumped storage power station. The RNG k-ε model and SMPLEC algorithms was used to simulate the internal flow fields. The result of the simulation was compared with the test data and good correspondence was got between experimental data and CFD result. Based on this model, internal flow analysis was carried out. The result show that when the pump turbine ran at the runway speed, lots of vortexes appeared in the flow passage of the runner. These vortexes could always be observed even if the guide vane opening changes. That is an important way of energy loss in the runaway condition. Pressure on two sides of the runner blades were almost the same. So the runner power is very low. High speed induced large centrifugal force and the small guide vane opening gave the water velocity a large tangential component, then an obvious water ring could be observed between the runner blades and guide vanes in small guide vane opening condition. That ring disappeared when the opening bigger than 20°. These conclusions can provide a theory basis for the analysis and simulation of the pump turbine runaway points.

Strategies for prevention or reduction of drug use for adolescents: systematic literature review

Directory of Open Access Journals (Sweden)

Thamyris Alexandre Salles

2016-06-01

Full Text Available A systematic review was conducted with the objective of identifying scientific evidence of strategies for prevention or reduction of drug use among adolescents. Searches were conducted in databases LILACS, CINAHL, MEDLINE, Scopus and Cochrane Library, with descriptors Ensino, Educação em Saúde, Transtornos relacionados ao uso de substâncias, Adolescentes and Enfermagem Psiquiátrica. Twenty-seven articles were chosen. Results pointed to a variety of software, projects and interventions that are used as strategies for prevention or reduction of drug use among adolescents. Among the studies, 74.1% (n=20 reached satisfactory results and 25.9% (n=7 reached partially satisfactory results. Only Narconon Project and Brief Intervention were widely effective in reducing use of a variety of drugs among adolescents, since the other studies were focused on specific drugs or were limited to use prevention among non-using adolescents.

Runaway Reaction: Solving for X.

Science.gov (United States)

Bartz, Solveig A.

2003-01-01

This article examines the runaway reaction as it was displayed by Barry, a 14-year-old eighth-grade boy with learning disabilities. It identifies some of the common characteristics of this response and proposes school intervention methods. Functional behavioral assessments and strength-based assessments are encouraged, along with using strategy…

Using Anti-Tobacco Industry Messages to Prevent Smoking among High-Risk Adolescents

Science.gov (United States)

Thrasher, James F.; Niederdeppe, Jeffrey D.; Jackson, Christine; Farrelly, Matthew C.

2006-01-01

Media campaigns to prevent adolescent tobacco use in the United States increasingly focus on the deceitful practices of the tobacco industry; however, little is known about how adolescents at elevated smoking risk respond to this strategy. This study used data from a nationally representative survey of 10,035 adolescents, ages 12-17 years, in…

Runaway electron beam generation and mitigation during disruptions at JET-ILW

Czech Academy of Sciences Publication Activity Database

Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Boboc, A.; Brezinsek, S.; Coffey, I.; Decker, J.; Drewelow, P.; Devaux, S.; de Vries, P.C.; Fil, A.; Gerasimov, S.; Giacomelli, L.; Jachmich, S.; Khilkevitch, E.M.; Kiptily, V.; Koslowski, R.; Kruezi, U.; Lehnen, M.; Lupelli, I.; Lomas, P. J.; Manzanares, A.; Martin De Aguilera, A.; Matthews, G.F.; Mlynář, Jan; Nardon, E.; Nilsson, E.; Perez von Thun, C.; Riccardo, V.; Saint-Laurent, F.; Shevelev, A.E.; Sips, G.; Sozzi, C.

2015-01-01

Roč. 55, č. 9 (2015), 093013-093013 ISSN 0029-5515 Institutional support: RVO:61389021 Keywords : runaway electrons * disruptions * tokamak * JET * massive gas injection * disruption mitigation * runaway background plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015 http://iopscience.iop.org/article/10.1088/0029-5515/55/9/093013

Let us prevent the next explosion in hazardous environments

Energy Technology Data Exchange (ETDEWEB)

Bhalla, Jogen [Amot Controls Corporation, Houston, TX (United States)

2012-07-01

There are many potential ignition sources in the oil and gas industry (drilling, petrochemical, refining and production). Some of them are hot work, internal combustion engines, improperly classified or maintained electrical equipment, lighting, and adjacent fire equipment. These are typically controlled using measures such as hot work permits for: - Welding/burning - Hot work or vehicle entry permit requirements to operate engines inside posted areas - Proper electrical classification along with maintenance programs - Programs/practices to prevent and detect releases of flammable materials A large number of diesel engines (in vehicles, lighting towers, power generators and other equipment) are used in the oil and gas industry for day-to-day operations. Diesel engine runaway is a serious hazard where flammable hydrocarbon emissions or leaks may occur. Hydrocarbons drawn into diesel engines through the air intake system act as an uncontrolled fuel source and can lead to dangerous engine overspeed or runaway. When an operator cannot shut down the engine using conventional methods (i.e. turning off the engine ignition switch) it could result in a total runaway engine. These could range from minor engine damage to engine and plant explosion, causing catastrophic damage to the equipment and surrounding facilities and/or death or injuries, such as the Texas City refinery and Deep water Horizon explosions. Fortunately, there is simple, inexpensive technology available which can prevent a diesel engine runaway. The paper is presented to increase awareness and lessons learned from many accidents involving runaway diesel engines. The author will present what companies are doing around the world to avoid diesel engine runaway as an ignition source for explosions in the hydrocarbon industry. (author)

45 CFR 1351.18 - What criteria has HHS established for deciding which Runaway and Homeless Youth Program grant...

Science.gov (United States)

2010-10-01

... which Runaway and Homeless Youth Program grant applications to fund? 1351.18 Section 1351.18 Public... SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.18 What criteria has HHS established for deciding which Runaway and Homeless Youth Program grant applications to...

Mechanistic elucidation of thermal runaway in potassium-ion batteries

Science.gov (United States)

Adams, Ryan A.; Varma, Arvind; Pol, Vilas G.

2018-01-01

For the first time, thermal runaway of charged graphite anodes for K-ion batteries is investigated, using differential scanning calorimetry (DSC) to probe the exothermic degradation reactions. Investigated parameters such as state of charge, cycle number, surface area, and binder demonstrate strong influences on the DSC profiles. Thermal runaway initiates at 100 °C owing to KxC8 - electrolyte reactions, but the K-ion graphite anode evolves significantly less heat as compared to the analogous Li-ion system (395 J g-1 vs. 1048 J g-1). The large volumetric expansion of graphite during potassiation cracks the SEI layer, enabling contact and reaction of KC8 - electrolyte, which diminishes with cycle number due to continuous SEI growth. High surface area graphite decreases the total heat generation, owing to thermal stability of the K-ion SEI layer. These findings illustrate the dynamic nature of K-ion thermal runaway and its many contrasts with the Li-ion graphite system, permitting possible engineering solutions for safer batteries.

Prevention of Adolescent Depression in the Spanish-Speaking World

Directory of Open Access Journals (Sweden)

Andrea B. Horn

2014-05-01

Full Text Available This paper aims at presenting programs targeted at the prevention of adolescent depression applied with Spanish-speaking populations that have been developed in Spanish-speaking countries and are mostly published in Spanish. These programs have been developed under different cultural contexts in Spain and Latin-America. The main goal of this paper is to make the studies and movements of the Spanish-speaking literature in this field accessible to the non-Spanish-speaking part of the research community. Therefore, after an introduction referring to possible cultural differences regarding depression in general and epidemiological basics, several programs are introduced. In total 11 programs will be shortly presented and discussed. After revising the programs it can be concluded that in the Spanish-speaking world many programs have been developed and conducted following current state of the art-approaches for adolescent depression prevention. Further research is needed especially targeting possible cultural and contextual aspects of prevention measures and their efficacy and efficiency.

Prevention of adolescent depression in the Spanish-speaking world.

Science.gov (United States)

Horn, Andrea B; Cañizares, Catalina; Gómez, Yvonne

2014-05-27

This paper aims at presenting programs targeted at the prevention of adolescent depression applied with Spanish-speaking populations that have been developed in Spanish-speaking countries and are mostly published in Spanish. These programs have been developed under different cultural contexts in Spain and Latin-America. The main goal of this paper is to make the studies and movements of the Spanish-speaking literature in this field accessible to the non-Spanish-speaking part of the research community. Therefore, after an introduction referring to possible cultural differences regarding depression in general and epidemiological basics, several programs are introduced. In total 11 programs will be shortly presented and discussed. After revising the programs it can be concluded that in the Spanish-speaking world many programs have been developed and conducted following current state of the art-approaches for adolescent depression prevention. Further research is needed especially targeting possible cultural and contextual aspects of prevention measures and their efficacy and efficiency.

Remote Shutoff Stops Runaway Lawnmower

Science.gov (United States)

Grambo, Alan A.

2007-01-01

In this article, the author describes how electronics students at Central Nine Career Center designed a kill switch circuit to stop a runaway lawnmower. This project is ideal for a career center since the electronics/robotics, small engines and horticulture classes can all work together on their respective parts of the modification, installation…

Can Increased CO2 Levels Trigger a Runaway Greenhouse on the Earth?

Science.gov (United States)

Ramirez, R.

2014-04-01

Recent one-dimensional (globally averaged) climate model calculations suggest that increased atmospheric CO2 could conceivably trigger a runaway greenhouse if CO2 concentrations were approximately 100 times higher than today. The new prediction runs contrary to previous calculations, which indicated that CO2 increases could not trigger a runaway, even at Venus-like CO2 concentrations. Goldblatt et al. argue that this different behavior is a consequence of updated absorption coefficients for H2O that make a runaway more likely. Here, we use a 1-D cloud-free climate model with similar, up-to-date absorption coefficients, but with a self-consistent methodology, to demonstrate that CO2 increases cannot induce a runaway greenhouse on the modern Earth. However, these initial calculations do not include cloud feedback, which may be positive at higher temperatures, destabilizing Earth's climate. We then show new calculations demonstrating that cirrus clouds cannot trigger a runaway, even in the complete absence of low clouds. Thus, the habitability of an Earth-like planet at Earth's distance appears to be ensured, irrespective of the sign of cloud feedback. Our results are of importance to Earth-like planets that receive similar insolation levels as does the Earth and to the ongoing question about cloud response at higher temperatures.

Child Sexual Abuse and Adolescent Prostitution: A Comparative Analysis.

Science.gov (United States)

Seng, Magnus J.

1989-01-01

Explored relationship between sexual abuse and adolescent prostitution by comparing 70 sexually abused children with 35 prostitution-involved children on 22 variables. Findings suggest that relationship is not direct, but involves runaway behavior as intervening variable. Concludes that it is not so much sexual abuse that leads to prostitution, as…

Depressive Symptoms Moderate Dating Violence Prevention Outcomes Among Adolescent Girls.

Science.gov (United States)

Collibee, Charlene; Rizzo, Christie J; Kemp, Kathleen; Hood, Erik; Doucette, Hannah; Gittins Stone, Daniel I; DeJesus, Brett

2018-04-01

Few dating violence prevention programs assess how variations in initial violence risk affects responsiveness. This study examines the efficacy of Date SMART, a dating violence and sexual risk prevention program designed to target high-risk adolescent girls, in preventing dating violence in the context of varying initial levels of depressive symptoms. A diverse sample of N = 109 female adolescents with a history of physical dating violence participated in a randomized controlled trial of the Date SMART program and a knowledge only (KO) comparison. Using baseline depression level as a primary risk factor, a series of multilevel models revealed significant main effects of baseline depression such that higher baseline depression was associated with greater physical dating violence perpetration and victimization. Results also showed a three-way interaction for assessment point, depressive symptoms, and condition for physical dating violence perpetration. Specifically, those with higher baseline depression in Date SMART showed significantly less physical dating violence perpetration at follow-ups compared with those with higher baseline depression in the KO group. This difference in violence reduction between conditions was not observed for those with lower baseline depression. Date SMART appears to effectively reduce physical dating violence perpetration in those with higher levels of initial risk. Current findings support that adolescents with different risk profiles respond differently to violence prevention programs.

Investigation of a High Head Francis Turbine at Runaway Operating Conditions

Directory of Open Access Journals (Sweden)

Chirag Trivedi

2016-03-01

Full Text Available Hydraulic turbines exhibit total load rejection during operation because of high fluctuations in the grid parameters. The generator reaches no-load instantly. Consequently, the turbine runner accelerates to high speed, runaway speed, in seconds. Under common conditions, stable runaway is only reached if after a load rejection, the control and protection mechanisms both fail and the guide vanes cannot be closed. The runner life is affected by the high amplitude pressure loading at the runaway speed. A model Francis turbine was used to investigate the consequences at the runaway condition. Measurements and simulations were performed at three operating points. The numerical simulations were performed using standard k-ε, k-ω shear stress transport (SST and scale-adaptive simulation (SAS models. A total of 12.8 million hexahedral mesh elements were created in the complete turbine, from the spiral casing inlet to the draft tube outlet. The experimental and numerical analysis showed that the runner was subjected to an unsteady pressure loading up to three-times the pressure loading observed at the best efficiency point. Investigates of unsteady pressure pulsations at the vaneless space, runner and draft tube are discussed in the paper. Further, unsteady swirling flow in the blade passages was observed that was rotating at a frequency of 4.8-times the runaway runner angular speed. Apart from the unsteady pressure loading, the development pattern of the swirling flow in the runner is discussed in the paper.

Preventing Adolescent Risk Behavior in the Rural Context: An Integrative Analysis of Adolescent, Parent, and Provider Perspectives

Science.gov (United States)

Rishel, Carrie W.; Cottrell, Lesley; Kingery, Tricia

2012-01-01

Adolescent risk behavior remains prevalent and contributes to numerous social problems and growing health care costs. Contrary to popular perception, adolescents in rural areas engage in risky behaviors at least as much as youth from urban or suburban settings. Little research, however, focuses on risk behavior prevention in the rural context.…

Runaway electron damage to the Tore Supra Phase III outboard pump limiter

International Nuclear Information System (INIS)

Nygren, R.; Lutz, T.; Walsh, D.; Martin, G.; Chatelier, M.; Loarer, T.; Guilhem, D.

1996-01-01

Operation of the Phase III outboard pump limiter (OPL) in Tore Supra in 1994 was terminated prematurely when runaway electrons during the current decay following a disruption pierced leading edge tube on the electron side and caused a water leak. The location, about 20 mm outside the last closed flux surface during normal operation, and the infrared (IR) images of the limiter indicate that the runaways moved in large outward steps, i.e. tens of millimeters, in one toroidal revolution. For plasma (runaway) currents in the range of 155 to 250 kA, the drift orbits open to the outside. Basic trajectory computations suggest that such motion is possible under the conditions present for this experiment. Activation measurements made on sections of the tube to indicate the area of local damage are presented here. An understanding of this event may provide important guidance regarding the potential damage from runaways in future tokamaks

Relativistic runaway breakdown in low-frequency radio

DEFF Research Database (Denmark)

Fullekrug, M.; Roussel-Dupre, R.; Symbalisty, E.M.D.

2011-01-01

at a distance of similar to 550 km. The measured broadband pulses occur similar to 4-9 ms after the sprite-producing lightning discharge, they exhibit electromagnetic radiation which mainly spans the frequency range from similar to 50 to 350 kHz, and they exhibit complex waveforms without the typical...... electromagnetic pulses and possibly generates sprites. The source location of the broadband pulses can be determined with an interferometric network of wideband low-frequency radio receivers to lend further experimental support to the relativistic runaway breakdown theory.......The electromagnetic radiation emitted by an electron avalanche beam resulting from relativistic runaway breakdown within the Earth's atmosphere is investigated. It is found from theoretical modeling with a computer simulation that the electron beam emits electromagnetic radiation which...

Adolescent pre-exposure prophylaxis for HIV prevention: current perspectives

Directory of Open Access Journals (Sweden)

Machado DM

2017-11-01

Full Text Available Daisy Maria Machado,1 Alexandre Machado de Sant’Anna Carvalho,2 Rachel Riera3 1Disciplina de Infectologia Pediátrica, Departamento de Pediatria, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, 2Universidade Federal do Rio de Janeiro, Rio de Janeiro, 3Disciplina de Medicina Baseada em Evidências, Departamento de Medicina, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil Abstract: Adolescents are a critical population that is disproportionately impacted by the HIV epidemic. More than 2 million adolescents between the age group of 10 and 19 years are living with HIV, and millions are at risk of infection. HIV risks are considerably higher among girls, especially in high-prevalence settings such as eastern and southern Africa. In addition to girls, there are other vulnerable adolescent subgroups, such as teenagers, who use intravenous (IV drugs, gay and bisexual boys, transgender youth, male sex workers, and people who fall into more than one of these categories. Pre-exposure prophylaxis (PrEP is a new intervention for people at high risk for acquiring HIV, with an estimated HIV incidence of >3%. Recent data from trials show evidence of the efficacy of PrEP as a powerful HIV prevention tool in high-risk populations, including men who have sex with men, HIV-1-serodiscordant heterosexual couples, and IV drug users. The reported efficacy in those trials of the daily use of oral tenofovir, alone or in combination with emtricitabine, to prevent HIV infection ranged from 44% to 75% and was heavily dependent on adherence. Despite the proven efficacy of PrEP in adult trials, concerns remain about its feasibility in real-life scenarios due to stigma, cost, and limited clinician experience with PrEP delivery. Recent studies are attempting to expand the inquiry into the efficacy of such HIV prophylaxis approaches in adolescent populations, but there are still many gaps in knowledge, and no

Fokker-Planck simulation of runaway electron generation in disruptions with the hot-tail effect

Energy Technology Data Exchange (ETDEWEB)

Nuga, H., E-mail: nuga@p-grp.nucleng.kyoto-u.ac.jp; Fukuyama, A. [Department of Engineering, Kyoto University, Kyoto 615-8540 (Japan); Yagi, M. [National Institutes for Quantum and Radiological Science and Technology, Aomori 039-3212 (Japan)

2016-06-15

To study runaway electron generation in disruptions, we have extended the three-dimensional (two-dimensional in momentum space; one-dimensional in the radial direction) Fokker-Planck code, which describes the evolution of the relativistic momentum distribution function of electrons and the induced toroidal electric field in a self-consistent manner. A particular focus is placed on the hot-tail effect in two-dimensional momentum space. The effect appears if the drop of the background plasma temperature is sufficiently rapid compared with the electron-electron slowing down time for a few times of the pre-quench thermal velocity. It contributes to not only the enhancement of the primary runaway electron generation but also the broadening of the runaway electron distribution in the pitch angle direction. If the thermal energy loss during the major disruption is assumed to be isotropic, there are hot-tail electrons that have sufficiently large perpendicular momentum, and the runaway electron distribution becomes broader in the pitch angle direction. In addition, the pitch angle scattering also yields the broadening. Since the electric field is reduced due to the burst of runaway electron generation, the time required for accelerating electrons to the runaway region becomes longer. The longer acceleration period makes the pitch-angle scattering more effective.

76 FR 22785 - Direct Certification and Certification of Homeless, Migrant and Runaway Children for Free School...

Science.gov (United States)

2011-04-25

... [FNS-2008-0001] RIN 0584-AD60 Direct Certification and Certification of Homeless, Migrant and Runaway... concerning the certification of certain children who are homeless, runaway, or migratory. This rule affects... children who are homeless, runaway, or migratory, as determined by the homeless coordinator for homeless or...

45 CFR 1351.12 - Who gets priority for the award of a Runaway and Homeless Youth Program grant?

Science.gov (United States)

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Who gets priority for the award of a Runaway and... FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.12 Who gets priority for the award of a Runaway and...

Effectiveness of a citywide patient immunization navigator program on improving adolescent immunizations and preventive care visit rates.

Science.gov (United States)

Szilagyi, Peter G; Humiston, Sharon G; Gallivan, Sarah; Albertin, Christina; Sandler, Martha; Blumkin, Aaron

2011-06-01

To assess the impact of a tiered patient immunization navigator intervention (immunization tracking, reminder/recall, and outreach) on improving immunization and preventive care visit rates in urban adolescents. Randomized clinical trial allocating adolescents (aged 11-15 years) to intervention vs standard of care control. Eight primary care practices. Population-based sample of adolescents (N = 7546). Immunization navigators at each practice implemented a tiered protocol: immunization tracking, telephone or mail reminder/recall, and home visits if participants remained unimmunized or behind on preventive care visits. Immunization rates at study end. Secondary outcomes were preventive care visit rates during the previous 12 months and costs. The intervention and control groups were similar at baseline for demographics (mean age, 13.5 years; 63% black, 14% white, and 23% Hispanic adolescents; and 74% receiving Medicaid), immunization rates, and preventive care visit rates. Immunization rates at the end of the study were 44.7% for the intervention group and 32.4% for the control group (adjusted risk ratio, 1.4; 95% confidence interval, 1.3-1.5); preventive care visit rates were 68.0% for the intervention group and 55.2% for the control group (1.2; 1.2-1.3). Findings were similar across practices, sexes, ages, and insurance providers. The number needed to treat for immunizations and preventive care visits was 9. The intervention cost was $3.81 per adolescent per month; the cost per additional adolescent fully vaccinated was $465, and the cost per additional adolescent receiving a preventive care visit was $417. A tiered tracking, reminder/recall, and outreach intervention improved immunization and preventive care visit rates in urban adolescents. clinicaltrials.gov Identifier: NCT00581347.

Field O stars: formed in situ or as runaways?

Science.gov (United States)

Gvaramadze, V. V.; Weidner, C.; Kroupa, P.; Pflamm-Altenburg, J.

2012-08-01

A significant fraction of massive stars in the Milky Way and other galaxies are located far from star clusters and star-forming regions. It is known that some of these stars are runaways, i.e. possess high space velocities (determined through the proper motion and/or radial velocity measurements), and therefore most likely were formed in embedded clusters and then ejected into the field because of dynamical few-body interactions or binary-supernova explosions. However, there exists a group of field O stars whose runaway status is difficult to prove via direct proper motion measurements (e.g. in the Magellanic Clouds) or whose (measured) low space velocities and/or young ages appear to be incompatible with their large separation from known star clusters. The existence of this group led some authors to believe that field O stars can form in situ. Since the question of whether or not O stars can form in isolation is of crucial importance for star formation theory, it is important to thoroughly test candidates of such stars in order to improve the theory. In this paper, we examine the runaway status of the best candidates for isolated formation of massive stars in the Milky Way and the Magellanic Clouds by searching for bow shocks around them, by using the new reduction of the Hipparcos data, and by searching for stellar systems from which they could originate within their lifetimes. We show that most of the known O stars thought to have formed in isolation are instead very likely runaways. We show also that the field must contain a population of O stars whose low space velocities and/or young ages are in apparent contradiction to the large separation of these stars from their parent clusters and/or the ages of these clusters. These stars (the descendants of runaway massive binaries) cannot be traced back to their parent clusters and therefore can be mistakenly considered as having formed in situ. We argue also that some field O stars could be detected in optical

Runaway transport studies in the TJ-I tokamak

International Nuclear Information System (INIS)

Rodriguez, L.; Vega, J.; Rodriguez-Yunta, A.; Castejon, F.; Pardo, C.; Navarro, A. P.

1994-01-01

Runaway diffusion coefficient, Dr, for TJ-I tokamak has been deduced using two different methods: In the first one, Dr is obtained using the steady state approach for values of the runaway confinement time Tτ r deduced from hard-X-ray bremsstrahlung spectra; in the second method, D r is deduced from sawteeth oscillations of HXR flux, and of SXR intensity, recorded simultaneously. Data have been taken in a scan with the toroidal magnetic field Bp Values obtained for Dr=[5-10] m 2 s ,decreasing with B Γ , are in both cases consistent. Assuming that magnetic turbulence is responsible for their transport, from D r we can deduce b/B Γ , the magnetic fluctuations level, and then infer the thermal conductivity coefficient χ c . The radial energy resolution of runaway electrons allow us to infer for b B Γ and χ c values at the plasma edge and for an inner position about r=a/2. Results are in good agreement with those ones obtained in TJ-I using probes, spectroscopic methods, power balance analysis and a coupled analysis for temperature and density pulses. (Author) 32 refs

In Their Own Words: Adolescents Strategies to Prevent Friend's Risk Taking

Science.gov (United States)

Buckley, Lisa; Chapman, Rebekah L.; Sheehan, Mary C.; Reveruzzi, Bianca N.

2014-01-01

Injury is a significant public health problem among youth. A primary cause of adolescent injury is risk-taking behavior, including alcohol use, interpersonal violence and road-related risks. A novel approach to prevention is building on friendships by encouraging adolescents to intervene into their friends' risk taking. Fifty-one early adolescents…

The Origin of B-type Runaway Stars: Non-LTE Abundances as a Diagnostic

Energy Technology Data Exchange (ETDEWEB)

McEvoy, Catherine M.; Dufton, Philip L.; Smoker, Jonathan V.; Keenan, Francis P. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN (United Kingdom); Lambert, David L. [The University of Texas at Austin, Department of Astronomy, RLM 16.316, Austin, TX 78712 (United States); Schneider, Fabian R. N. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); De Wit, Willem-Jan [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19 (Chile)

2017-06-10

There are two accepted mechanisms to explain the origin of runaway OB-type stars: the binary supernova (SN) scenario and the cluster ejection scenario. In the former, an SN explosion within a close binary ejects the secondary star, while in the latter close multibody interactions in a dense cluster cause one or more of the stars to be ejected from the region at high velocity. Both mechanisms have the potential to affect the surface composition of the runaway star. tlusty non-LTE model atmosphere calculations have been used to determine the atmospheric parameters and the C, N, Mg, and Si abundances for a sample of B-type runaways. These same analytical tools were used by Hunter et al. for their analysis of 50 B-type open-cluster Galactic stars (i.e., nonrunaways). Effective temperatures were deduced using the Si-ionization balance technique, surface gravities from Balmer line profiles, and microturbulent velocities derived using the Si spectrum. The runaways show no obvious abundance anomalies when compared with stars in the open clusters. The runaways do show a spread in composition that almost certainly reflects the Galactic abundance gradient and a range in the birthplaces of the runaways in the Galactic disk. Since the observed Galactic abundance gradients of C, N, Mg, and Si are of a similar magnitude, the abundance ratios (e.g., N/Mg) are as obtained essentially uniform across the sample.

On the generation of runaway electrons and their impact to plasma facing components

International Nuclear Information System (INIS)

Kawamura, Takaichi; Obayashi, Haruo; Miyahara, Akira.

1988-06-01

Runaway electrons accompanied by inductive or non-inductive plasma currents in a tokamak have severe interactions with plasma facing materials of a first wall, and influence the first wall structure due to activation and damage. In this paper, modelling of runaway electron generation near the wall in a tokamak is carried out. This includes the evaluation of acceleration along magnetic surfaces for relativistic electrons with energies larger than the runaway threshold. Penetration of runaway electrons of energy ranges from a few MeV to several ten MeV leads to gamma ray photon production by bremsstrahlung. One of the specific features of the impact on the first wall technology is that they give rise to activation due to giant resonance of the (γ,n) nuclear reaction and, as a consequence, cause a requirement of remote maintenance. The other is that they bring energy deposition at brazing areas between low Z material and metal, or at a metal itself, and they result in melting, cracking and grain growth. The methods to estimate these effects using nuclear data and material data on the basis of runaway flux modelling are introduced and examples of estimation are given. (author)

Street Kids--Homeless and Runaway Youth. Hearing before the Subcommittee on Children, Family, Drugs and Alcoholism of the Committee on Labor and Human Resources, United States Senate. One Hundred First Congress, Second Session.

Science.gov (United States)

Congress of the U.S., Washington, DC. Senate Committee on Labor and Human Resources.

This hearing was the second in a series examining the impact of homelessness and dislocation on young people in America. This session focused on the problems of homeless and runaway adolescents. Witnesses described the need for multiple services for this population, for effective provision of services, and for greater coordination and planning.…

The OB run-away stars from Sco-Cen and Orion reviewed

International Nuclear Information System (INIS)

Blaauw, A.

1989-01-01

The author studies the past paths of the run-away star Zeta Oph from the OB association Sco-Cen, and of the run-away stars AE Aur, Mu Col and 53 Ari from the OB association Ori OB1, in connection with the question of the origin of these high velocities. Should the binary-hypothesis be adhered to (supernova explosion of one of the components) or, perhaps, dynamical evolution in young, dense clusters offer a clue to this phenomenon? It is shown that the latter hypothesis is very unlikely to apply to Zeta Oph. For the run-away stars from Orion conclusive evidence may well be obtained in the course of the next decade, from improved accuracy of the proper motions

Effect of magnetic fluctuations on the confinement and dynamics of runaway electrons in the HT-7 tokamak

International Nuclear Information System (INIS)

Zhou, R.J.; Hu, L.Q.; Li, E.Z.; Xu, M.; Zhong, G.Q.; Xu, L.Q.; Lin, S.Y.

2013-01-01

Experimental results in the HT-7 tokamak indicated significant losses of runaway electrons due to magnetic fluctuations, but the loss processes did not only rely on the fluctuation amplitude. Efficient radial runaway transport required that there were no more than small regions of the plasma volume in which there was very low transport of runaways. A radial runaway diffusion coefficient of D_r ≈ 10 m"2s"-"1 was derived for the loss processes, and diffusion coefficient near the resonant magnetic surfaces and shielding factor ϒ = 0.8 were deduced. Test particle equations were used to analyze the effect of magnetic fluctuations on runaway dynamics. It was found that the maximum energy that runaways can gain is very sensitive to the value of a_s. a_s = (0.28 - 0.33) was found for the loss processes in the experiment, and maximum runaway energy could be controlled in the range of E = (4 MeV - 6 MeV) in this case. Additionally, to control the maximum runaway energy below 5 MeV, the normalized electric field needed to be under a critical value D_a = 6.8, and the amplitude normalized magnetic fluctuations b tilde needed to be at least of the order of b tilde ≈ 3 x 10"-"5. (author)

Use of Technology for HIV Prevention Among Adolescent and Adult Women in the United States.

Science.gov (United States)

Blackstock, Oni J; Patel, Viraj V; Cunningham, Chinazo O

2015-12-01

Although the proportion of new HIV infections in the USA among women has decreased over the last few years, still, approximately 20 % of new infections occur annually among adolescent and adult women. The development of effective evidence-based prevention interventions remains an important approach to further decreasing these numbers. Technology-delivered prevention interventions hold tremendous potential due, in part, to their ability to reach beyond the walls of brick-and-mortar intervention sites to engage individuals where they are. While most technology-delivered interventions have focused on adolescents and men who have sex with men, much fewer have specifically targeted adolescent or adult women despite evidence showing that interventions tailored to specific target populations are most effective. We summarize the recently published literature on technology-delivered HIV prevention interventions for US adolescent and adult women and provide suggestions for next steps in this nascent but emergent area of prevention research.

Precursors of Running Away during Adolescence: Do Peers Matter?

Science.gov (United States)

Chen, Xiaojin; Thrane, Lisa; Adams, Michele

2012-01-01

Although peer influence is a salient predictor of delinquency, how it operates in the etiology of runaway behavior is not fully understood. Using data from the National Longitudinal Study of Adolescent Health, this study demonstrates the importance of taking peers into account in understanding the etiology of running away. The findings suggest…

The Runaway Greenhouse Effect on Earth and other Planets

Science.gov (United States)

Rabbette, Maura; Pilewskie, Peter; McKay, Christopher; Young, Robert

2001-01-01

Water vapor is an efficient absorber of outgoing longwave infrared radiation on Earth and is the primary greenhouse gas. Since evaporation increases with increasing sea surface temperature, and the increase in water vapor further increases greenhouse warming, there is a positive feedback. The runaway greenhouse effect occurs if this feedback continues unchecked until all the water has left the surface and enters the atmosphere. For Mars and the Earth the runaway greenhouse was halted when water vapor became saturated with respect to ice or liquid water respectively. However, Venus is considered to be an example of a planet where the runaway greenhouse effect did occur, and it has been speculated that if the solar luminosity were to increase above a certain limit, it would also occur on the Earth. Satellite data acquired during the Earth Radiation Budget Experiment (ERBE) under clear sky conditions shows that as the sea surface temperature (SST) increases, the rate of outgoing infrared radiation at the top of the atmosphere also increases, as expected. Over the pacific warm pool where the SST exceeds 300 K the outgoing radiation emitted to space actually decreases with increasing SST, leading to a potentially unstable system. This behavior is a signature of the runaway greenhouse effect on Earth. However, the SST never exceeds 303K, thus the system has a natural cap which stops the runaway. According to Stefan-Boltzmann's law the amount of heat energy radiated by the Earth's surface is proportional to (T(sup 4)). However, if the planet has a substantial atmosphere, it can absorb all infrared radiation from the lower surface before the radiation penetrates into outer space. Thus, an instrument in space looking at the planet does not detect radiation from the surface. The radiation it sees comes from some level higher up. For the earth#s atmosphere the effective temperature (T(sub e)) has a value of 255 K corresponding to the middle troposphere, above most of the

Adolescent pre-exposure prophylaxis for HIV prevention: current perspectives

Science.gov (United States)

Machado, Daisy Maria; de Sant’Anna Carvalho, Alexandre Machado; Riera, Rachel

2017-01-01

Adolescents are a critical population that is disproportionately impacted by the HIV epidemic. More than 2 million adolescents between the age group of 10 and 19 years are living with HIV, and millions are at risk of infection. HIV risks are considerably higher among girls, especially in high-prevalence settings such as eastern and southern Africa. In addition to girls, there are other vulnerable adolescent subgroups, such as teenagers, who use intravenous (IV) drugs, gay and bisexual boys, transgender youth, male sex workers, and people who fall into more than one of these categories. Pre-exposure prophylaxis (PrEP) is a new intervention for people at high risk for acquiring HIV, with an estimated HIV incidence of >3%. Recent data from trials show evidence of the efficacy of PrEP as a powerful HIV prevention tool in high-risk populations, including men who have sex with men, HIV-1-serodiscordant heterosexual couples, and IV drug users. The reported efficacy in those trials of the daily use of oral tenofovir, alone or in combination with emtricitabine, to prevent HIV infection ranged from 44% to 75% and was heavily dependent on adherence. Despite the proven efficacy of PrEP in adult trials, concerns remain about its feasibility in real-life scenarios due to stigma, cost, and limited clinician experience with PrEP delivery. Recent studies are attempting to expand the inquiry into the efficacy of such HIV prophylaxis approaches in adolescent populations, but there are still many gaps in knowledge, and no country has yet approved it for use with adolescents. The aim of this review was to identify and summarize the evidence from studies on PrEP for adolescents. We have compiled and reviewed published studies focusing on safety, feasibility, adherence to therapeutics, self-perception, and legal issues related to PrEP in people aged between 10 and 24 years. PMID:29238237

Probing the heat sources during thermal runaway process by thermal analysis of different battery chemistries

Science.gov (United States)

Zheng, Siqi; Wang, Li; Feng, Xuning; He, Xiangming

2018-02-01

Safety issue is very important for the lithium ion battery used in electric vehicle or other applications. This paper probes the heat sources in the thermal runaway processes of lithium ion batteries composed of different chemistries using accelerating rate calorimetry (ARC) and differential scanning calorimetry (DSC). The adiabatic thermal runaway features for the 4 types of commercial lithium ion batteries are tested using ARC, whereas the reaction characteristics of the component materials, including the cathode, the anode and the separator, inside the 4 types of batteries are measured using DSC. The peaks and valleys of the critical component reactions measured by DSC can match the fluctuations in the temperature rise rate measured by ARC, therefore the relevance between the DSC curves and the ARC curves is utilized to probe the heat source in the thermal runaway process and reveal the thermal runaway mechanisms. The results and analysis indicate that internal short circuit is not the only way to thermal runaway, but can lead to extra electrical heat, which is comparable with the heat released by chemical reactions. The analytical approach of the thermal runaway mechanisms in this paper can guide the safety design of commercial lithium ion batteries.

Is a gender differential intervention necessary in the prevention of adolescent drug use?

Science.gov (United States)

Meneses, Carmen; Charro, Belén

2014-01-01

To examine the significant differences in smoking, drug and alcohol use between adolescent boys and girls, and to raise the possible need to design and implement prevention programs from a gender perspective. A qualitative study using eight discussion groups of adolescents aged 14-18 years (n=56) and 6 semi-structured interviews with experts and professionals in drug prevention in the Community of Madrid. Categorical interpretive analysis was performed. The adolescents and prevention professional indicated differences between boys and girls in drug and alcohol use. The significances, reasons associated with the consumption and the patterns of consumption were perceived differently by each sex. To lose weight, calm down or an image of rebelliousness was related to girls who smoked, while boys smoked less because they did more sports. The perception of certain precocity of drug consumption was associated with the step from school to Higher Education Institutions. They found smoking associated with a good social image among their groups. Adolescents showed the ineffectiveness of the campaigns and prevention messages they received, incoherence of adults between messages and actions, and the attraction of all behaviours that are banned. Professionals observed the need to include a gender perspective in prevention programs, but did not know how to achieve it, mainly because it has been translated into different activities for each sex until now. The significant differences associated with smoking, drug and alcohol use observed in the adolescents should lead us to design and implement prevention programs that incorporate a gender perspective. It is perhaps from this strategy where drug and alcohol use among girls can be reduced. Copyright © 2012 SEP y SEPB. Published by Elsevier España. All rights reserved.

A Runaway Yellow Supergiant Star in the Small Magellanic Cloud

Science.gov (United States)

Neugent, Kathryn F.; Massey, Philip; Morrell, Nidia I.; Skiff, Brian; Georgy, Cyril

2018-05-01

We recently discovered a yellow supergiant (YSG) in the Small Magellanic Cloud (SMC) with a heliocentric radial velocity of ∼300 km s‑1, which is much larger than expected for a star at its location in the SMC. This is the first runaway YSG ever discovered and only the second evolved runaway star discovered in a galaxy other than the Milky Way. We classify the star as G5-8 I and use de-reddened broad-band colors with model atmospheres to determine an effective temperature of 4700 ± 250 K, consistent with what is expected from its spectral type. The star’s luminosity is then log L/L ⊙ ∼ 4.2 ± 0.1, consistent with it being a ∼30 Myr 9 M ⊙ star according to the Geneva evolution models. The star is currently located in the outer portion of the SMC’s body, but if the star’s transverse peculiar velocity is similar to its peculiar radial velocity, in 10 Myr the star would have moved 1.°6 across the disk of the SMC and could easily have been born in one of the SMC’s star-forming regions. Based on its large radial velocity, we suggest it originated in a binary system where the primary exploded as a supernovae, thus flinging the runaway star out into space. Such stars may provide an important mechanism for the dispersal of heavier elements in galaxies given the large percentage of massive stars that are runaways. In the future, we hope to look into additional evolved runaway stars that were discovered as part of our other past surveys. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

Science.gov (United States)

Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

2016-01-01

A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

Adolescent transformations of behavioral and neural processes as potential targets for prevention.

Science.gov (United States)

Eldreth, Dana; Hardin, Michael G; Pavletic, Nevia; Ernst, Monique

2013-06-01

Adolescence is a transitional period in development that is marked by a distinct, typical behavioral profile of high rates of exploration, novelty-seeking, and emotional lability. While these behaviors generally assist the adolescent transition to independence, they can also confer vulnerability for excessive risk-taking and psychopathology, particularly in the context of specific environmental or genetic influences. As prevention research depends on the identification of targets of vulnerability, the following review will discuss the interplay among motivational systems including reward-related, avoidance-related, and regulatory processes in typical and atypical adolescent development. Each set of processes will be discussed in relation to their underlying neural correlates and distinct developmental trajectories. Evidence suggests that typical adolescent behavior and the risk for atypical development are mediated by heightened adolescent responsiveness of reward-related and avoidance-related systems under specific conditions, concurrent with poor modulation by immature regulatory processes. Finally, we will propose strategies to exploit heightened reward processing to reinforce inhibitory control, which is an essential component of regulatory processes in prevention interventions.

The Fourth R: A School-Based Adolescent Dating Violence Prevention Program

Directory of Open Access Journals (Sweden)

David A. Wolfe

2011-07-01

Full Text Available This paper presents a school-based primary prevention program (The Fourth R to prevent adolescent dating violence, and related risk behaviors. The cornerstone of The Fourth R is a 21-lesson skillbased curriculum delivered by teachers who receive specialized training, that promotes healthy relationships, and targets violence, high-risk sexual behavior, and substance use among adolescents. The Fourth R was evaluated in a cluster randomized trial in 20 schools. Results indicated that teaching youth healthy relationships and skills as part of their curriculum reduced physical dating violence, and increased condom use 2.5 years later.

On the Absence of Non-thermal X-Ray Emission around Runaway O Stars

Energy Technology Data Exchange (ETDEWEB)

Toalá, J. A. [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taipei 10617, Taiwan (China); Oskinova, L. M. [Institute for Physics and Astronomy, University of Potsdam, D-14476 Potsdam (Germany); Ignace, R. [Department of Physics and Astronomy, East Tennessee State University, Johnson City, TN 37614 (United States)

2017-04-01

Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ -ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emission from bow shocks using archived XMM-Newton observations for a clean sample of six well-determined runaway O stars. We find that none of these objects present diffuse X-ray emission associated with their bow shocks, similarly to previous X-ray studies toward ζ Oph and BD+43°3654. We carefully investigated multi-wavelength observations of AE Aur and could not confirm previous findings of non-thermal X-rays. We conclude that so far there is no clear evidence of non-thermal extended emission in bow shocks around runaway O stars.

Rural Runaways: Rurality and Its Implications for Services to Children and Young People Who Run Away

Science.gov (United States)

Franks, Myfanwy; Goswami, Haridhan

2010-01-01

This article debates options for service provision to young rural runaways in the UK. Using data drawn from two national surveys and follow-on qualitative studies, the authors trace urban myths of rurality and their effects on runaway provision. The authors review models of rural refuge, systemic advocacy and mobile services for rural runaways.…

Native American adolescents' views of fetal alcohol syndrome prevention in schools.

Science.gov (United States)

Ma, G X; Toubbeh, J; Cline, J; Chisholm, A

1998-04-01

Alcohol is the most commonly abused substance among adolescents in the United States. Adolescent females are recognized as one group at risk for giving birth to babies with fetal alcohol syndrome (FAS). Sixth through eighth grade Native Americans were surveyed about their attitudes toward and knowledge of FAS risk factors and prevention strategies. Data revealed that 52% of students drank alcohol prior to the survey. Though sexually active, students lacked knowledge about the relationship between alcohol and FAS. The study revealed 1) limited prevention programs in middle schools and 2) the most influential factor in determining attitudes and decisions about alcohol use was the immediate family. Students felt FAS prevention is an important topic in school health education, noting the important role peers play in teaching and role modeling. Various strategies incorporating music and communication technology such as videotape and computer-assisted interactive tools into prevention materials are discussed.

Preventing Adolescent Social Anxiety and Depression and Reducing Peer Victimization: Intervention Development and Open Trial

Science.gov (United States)

La Greca, Annette M.; Ehrenreich-May, Jill; Mufson, Laura; Chan, Sherilynn

2016-01-01

Background Social anxiety disorder (SAD) and depression are common among adolescents, frequently comorbid, and resistant to change. Prevention programs for adolescent SAD are scant, and depression prevention programs do not fully address peer-risk factors. One critical peer-risk factor for SAD and depression is peer victimization. We describe the development and initial evaluation of a transdiagnostic school-based preventive intervention for adolescents with elevated symptoms of social anxiety and/or depression and elevated peer victimization. We modified Interpersonal Psychotherapy-Adolescent Skills Training for depression, incorporating strategies for dealing with social anxiety and peer victimization. Objective Our open trial assessed the feasibility, acceptability, and preliminary benefit of the modified program (called UTalk) for adolescents at risk for SAD or depression and who also reported peer victimization. Method Adolescents (N=14; 13–18 years; 79% girls; 86% Hispanic) were recruited and completed measures of peer victimization, social anxiety, and depression both pre- and post-intervention and provided ratings of treatment satisfaction. Independent evaluators (IEs) rated youths’ clinical severity. The intervention (3 individual and 10 group sessions) was conducted weekly during school. Results Regarding feasibility, 86% of the adolescents completed the intervention (M attendance=11.58 sessions). Satisfaction ratings were uniformly positive. Intention-to-treat analyses revealed significant declines in adolescent- and IE-rated social anxiety and depression and in reports of peer victimization. Additional secondary benefits were observed. Conclusions Although further evaluation is needed, the UTalk intervention appears feasible to administer in schools, with high satisfaction and preliminary benefit. Implications for research on the prevention of adolescent SAD and depression are discussed. PMID:27857509

Perceptions of oral health, preventive care, and care-seeking behaviors among rural adolescents.

Science.gov (United States)

Dodd, Virginia J; Logan, Henrietta; Brown, Cameron D; Calderon, Angela; Catalanotto, Frank

2014-12-01

An asymmetrical oral disease burden is endured by certain population subgroups, particularly children and adolescents. Reducing oral health disparities requires understanding multiple oral health perspectives, including those of adolescents. This qualitative study explores oral health perceptions and dental care behaviors among rural adolescents. Semistructured individual interviews with 100 rural, minority, low socioeconomic status adolescents revealed their current perceptions of oral health and dental care access. Respondents age ranged from 12 to 18 years. The sample was 80% black and 52% male. Perceived threat from dental disease was low. Adolescents perceived regular brushing and flossing as superseding the need for preventive care. Esthetic reasons were most often cited as reasons to seek dental care. Difficulties accessing dental care include finances, transportation, fear, issues with Medicaid coverage and parental responsibility. In general, adolescents and their parents are in need of information regarding the importance of preventive dental care. Findings illuminate barriers to dental care faced by low-income rural adolescents and counter public perceptions of government-sponsored dental care programs as being "free" or without cost. The importance of improved oral health knowledge, better access to care, and school-based dental care is discussed. © 2014, American School Health Association.

Dynamics of runaway tails with time-dependent sub-Dreicer dc fields in magnetized plasmas

International Nuclear Information System (INIS)

Moghaddam-Taaheri, E.; Vlahos, L.

1987-01-01

The evolution of runaway tails driven by sub-Dreicer time-dependent dc fields in a magnetized plasma are studied numerically using a quasilinear code based on the Ritz--Galerkin method and finite elements. It is found that the runaway tail maintained a negative slope during the dc field increase. Depending on the values of the dc electric field at t = 0 and the electron gyrofrequency to the plasma frequency ratio the runaway tail became unstable to the anomalous Doppler resonance or remained stable before the saturation of the dc field at some maximum value. The systems that remained stable during this stage became unstable to the anomalous Doppler or the Cerenkov resonances when the dc field was kept at the saturation level or decreased. Once the instability is triggered, the runaway tail is isotropized

Dynamics of runaway tails with time-dependent sub-Dreicer dc fields in magnetized plasmas

Science.gov (United States)

Moghaddam-Taaheri, E.; Vlahos, L.

1987-01-01

The evolution of runaway tails driven by sub-Dreicer time-dependent dc fields in a magnetized plasma are studied numerically using a quasi-linear code based on the Ritz-Galerkin method and finite elements. It is found that the runaway tail maintained a negative slope during the dc field increase. Depending on the values of the dc electric field at t = 0 and the electron gyrofrequency to the plasma frequency ratio the runaway tail became unstable to the anomalous Doppler resonance or remained stable before the saturation of the dc field at some maximum value. The systems that remained stable during this stage became unstable to the anomalous Doppler or the Cerenkov resonances when the dc field was kept at the saturation level or decreased. Once the instability is triggered, the runaway tail is isotropized.

Resourcing resilience: social protection for HIV prevention amongst children and adolescents in Eastern and Southern Africa.

Science.gov (United States)

Toska, Elona; Gittings, Lesley; Hodes, Rebecca; Cluver, Lucie D; Govender, Kaymarlin; Chademana, K Emma; Gutiérrez, Vincent Evans

2016-07-01

Adolescents are the only age group with growing AIDS-related morbidity and mortality in Eastern and Southern Africa, making HIV prevention research among this population an urgent priority. Structural deprivations are key drivers of adolescent HIV infection in this region. Biomedical interventions must be combined with behavioural and social interventions to alleviate the socio-structural determinants of HIV infection. There is growing evidence that social protection has the potential to reduce the risk of HIV infection among children and adolescents. This research combined expert consultations with a rigorous review of academic and policy literature on the effectiveness of social protection for HIV prevention among children and adolescents, including prevention for those already HIV-positive. The study had three goals: (i) assess the evidence on the effectiveness of social protection for HIV prevention, (ii) consider key challenges to implementing social protection programmes that promote HIV prevention, and (iii) identify critical research gaps in social protection and HIV prevention, in Eastern and Southern Africa. Causal pathways of inequality, poverty, gender and HIV risk require flexible and responsive social protection mechanisms. Results confirmed that HIV-inclusive child-and adolescent-sensitive social protection has the potential to interrupt risk pathways to HIV infection and foster resilience. In particular, empirical evidence (literature and expert feedback) detailed the effectiveness of combination social protection particularly cash/in-kind components combined with "care" and "capability" among children and adolescents. Social protection programmes should be dynamic and flexible, and consider age, gender, HIV-related stigma, and context, including cultural norms, which offer opportunities to improve programmatic coverage, reach and uptake. Effective HIV prevention also requires integrated social protection policies, developed through strong national

On the origin of the hypervelocity runaway star HD271791

OpenAIRE

Gvaramadze, V. V.

2009-01-01

We discuss the origin of the runaway early B-type star HD271791 and show that its extremely high velocity (\\simeq 530-920 km/s) cannot be explained within the framework of the binary-supernova ejection scenario. Instead, we suggest that HD271791 attained its peculiar velocity in the course of a strong dynamical encounter between two hard massive binaries or via an exchange encounter between a hard massive binary and a very massive star, formed through runaway mergers of ordinary massive stars...

Radio-frequency wave enhanced runaway production rate

International Nuclear Information System (INIS)

Chan, V.S.; McClain, F.W.

1983-01-01

Enhancement of runaway electron production (over that of an Ohmic discharge) can be achieved by the addition of radio-frequency waves. This effect is studied analytically and numerically using a two-dimensional Fokker--Planck quasilinear equation

Generación y dinámica de electrones runaway en plasmas tokamak

OpenAIRE

Fernández Gómez, Isabel

2016-01-01

La dinámica y generación de electrones runaway en plasmas tokamak constituye el tema central de esta tesis. En un tokamak, el fenómeno runaway es el resultado de la existencia de un campo eléctrico en dirección toroidal. Aquellos electrones cuya velocidad excede un cierto valor crítico se aceleran de forma continua, ya que la e ciencia de las colisiones para disipar la energía ganada en el campo disminuye con la velocidad (∼ ⁻¹) . Se tiene entonces lo que se conoce como un electrón runaway. ...

Effects of discharge cleaning on the production of runaway electrons in TORTUS tokamak

Energy Technology Data Exchange (ETDEWEB)

Cross, R C; Liu, J R; Giannone, L. (Sydney Univ. (Australia). School of Physics)

1983-06-01

Experimental results are presented on the production of runaway electrons as a function of wall cleanliness in the TORTUS tokamak. When the walls are clean, the production rate decreases as the filling pressure increases. When the walls are contaminated by oxygen, the production rate can increase when the filling pressure is increased, owing to the production of water vapour during tokamak discharges. These results resolve the differences reported in the literature on the production of runaways as a function of filling pressure. It is also observed that the runaway electron instability seen in other devices is suppressed when the walls are discharge-cleaned.

Power-law and runaway growth in conserved aggregation systems

International Nuclear Information System (INIS)

Yamamoto, Hiroshi; Ohtsuki, Toshiya; Fujihara, Akihiro; Tanimoto, Satoshi

2006-01-01

The z-transform technique is used to analyze the Smoluchowski coagulation equation for conserved aggregation systems. A universal power law with the exponent -5/2 appears when a total 'mass' has a certain critical value. Below the threshold, ordinary scaling relations hold and the system exhibits a behavior like usual critical phenomena. Above the threshold, in contrast, the excess amount of mass coagulates into a runaway member, and remaining members follow the power law. Here the runaway growth coexists with the power law. It is argued that these behaviors are observed universally in conserved aggregation processes

Time and energy resolved runaway measurements in TFR from induced radioactivity

International Nuclear Information System (INIS)

1983-09-01

A time and energy resolved measurement of the radioactivity induced by runaway electrons in proper samples has been developped in TFR. The data give an information on the confinement time of these electrons, which appears to be strongly dependent on the toroidal field, suggesting the onset of a magnetic turbulence at lower fields. Observations showing that the runaway electrons deeply penetrate into the limiter shadow are also reported

Long-term effects of adolescent marijuana use prevention on adult mental health services utilization: the midwestern prevention project.

Science.gov (United States)

Riggs, Nathaniel R; Pentz, Mary Ann

2009-01-01

Evaluated were effects of a drug abuse(1) prevention program, previously shown to prevent marijuana use in adolescence, on adulthood mental health service use. Analyses were conducted on 961 6th (41%) and 7th (59%) grade participants randomly assigned to intervention or control groups at baseline in 1984. These participants were followed-up through 2003 representing 15 waves of data collection. Eighty-five percent of participants were Caucasian and 56% were female. The hypothesis was that direct program effects on early adulthood mental health service use would be mediated by program effects on high school marijuana use trajectories. Structural equation models, imputing for missing data, demonstrated that MPP (Midwestern Prevention Project) program effects on mental health were mediated by the marijuana use growth curve intercept. Findings support the role of early adolescent drug use prevention programs in impacting later mental health problems. The study's limitations are noted.

Preventing Adolescent Social Anxiety and Depression and Reducing Peer Victimization: Intervention Development and Open Trial

Science.gov (United States)

La Greca, Annette M.; Ehrenreich-May, Jill; Mufson, Laura; Chan, Sherilynn

2016-01-01

Background: Social anxiety disorder (SAD) and depression are common among adolescents, frequently comorbid, and resistant to change. Prevention programs for adolescent SAD are scant, and depression prevention programs do not fully address peer-risk factors. One critical peer-risk factor for SAD and depression is peer victimization. We describe the…

A Facebook-Based Obesity Prevention Program for Korean American Adolescents: Usability Evaluation.

Science.gov (United States)

Park, Bu Kyung; Nahm, Eun-Shim; Rogers, Valerie E; Choi, Mona; Friedmann, Erika; Wilson, Marisa; Koru, Gunes

Adolescent obesity is one of the most serious global public health challenges. Social networking sites are currently popular among adolescents. Therefore, the obesity prevention program for Korean American adolescents was developed on the most popular social networking site, Facebook. The purpose of this study was to evaluate the usability of a culturally tailored Facebook-based obesity prevention program for Korean American adolescents (Healthy Teens). An explorative descriptive design of usability testing was used. Usability testing employing one-on-one observation, the think-aloud method, audio taping, screen activity capture, and surveys was performed. Twenty participants were recruited from two Korean language schools (mean age, 15.40 ± 1.50 years). Recruitment and user testing was performed between February and April 2014. Content analysis, using the inductive coding approach, was performed by three coders to analyze transcriptions. Descriptive statistics were used to analyze quantitative data including demographic characteristics, perceived usability, eHealth literacy, and health behaviors. Testing revealed several usability issues in content, appearance, and navigation. Participants' comments regarding content were positive. Although the Facebook platform provided limited flexibility with respect to building the site, participants described the program's appearance as appropriate. Most participants did not experience difficulty in navigating the program. Our preliminary findings indicated that participants perceived the Healthy Teens program as usable and useful. This program could be used as a robust platform for the delivery of health education to adolescents. Further research is required to assess the effects of Facebook-based programs on adolescent obesity prevention. Copyright © 2016 National Association of Pediatric Nurse Practitioners. Published by Elsevier Inc. All rights reserved.

[Effectiveness of educational interventions for the prevention of pregnancy in adolescents].

Science.gov (United States)

Sanz-Martos, Sebastián; López-Medina, Isabel M; Álvarez-García, Cristina; Álvarez-Nieto, Carmen

2018-06-11

To assess the effectiveness of the interventions to prevent a pregnancy in adolescence. Systematic review. The following databases were consulted: PubMed, CINAHL, Scopus, Cuiden Plus, LILACS, and IME, in order to identify interventions aimed at preventing a pregnancy in adolescence. A total of 24 primary investigations, in which an educational program to prevent a pregnancy in the adolescence was evaluated, were selected. The quality of the selected studies was assessed according to the CASPe scale. Educational programs for the modification of the teenage pregnancy rate show inconclusive results, as there are 2 studies that find a reduction, and 2 that find that there are no significant changes. For secondary outcomes, it was found that educational programs are effective for increasing the knowledge level about sexuality and contraceptive methods and changing attitudes about the risk of a teenage pregnancy or the use of contraceptive methods. There are no statistically significant differences between the studies with a positive and negative outcome (P>.05) for any of the results analysed in this review. There is no a single intervention modality that is the most effective for prevention of a teenage pregnancy. More research is needed with a longitudinal approach that assess not only intermediate results, but also a modification in the pregnancy rate. Copyright © 2018 The Authors. Publicado por Elsevier España, S.L.U. All rights reserved.

Depression and Anxiety Prevention Based on Cognitive Behavioral Therapy for At-Risk Adolescents: A Meta-Analytic Review

Directory of Open Access Journals (Sweden)

Sanne P. A. Rasing

2017-06-01

Full Text Available Depression and anxiety disorders are among the most common mental disorders during adolescence. During this life phase, the incidence of these clinical disorders rises dramatically, and even more adolescents suffer from symptoms of depression or anxiety that are just below the clinical threshold. Both clinical and subclinical levels of depression or anxiety symptoms are related to decreased functioning in various areas, such as social and academic functioning. Prevention of depression and anxiety in adolescents is therefore imperative. We conducted a meta-analytic review of the effects of school-based and community-based prevention programs that are based on cognitive behavioral therapy with the primary goal preventing depression, anxiety, or both in high risk adolescents. Articles were obtained by searching databases and hand searching reference lists of relevant articles and reviews. The selection process yielded 32 articles in the meta-analyses. One article reported on two studies and three articles reported on both depression and anxiety. This resulted in a total of 36 studies, 23 on depression and 13 on anxiety. For depression prevention aimed at high risk adolescents, meta-analysis showed a small effect of prevention programs directly after the intervention, but no effect at 3–6 months and at 12 months follow-up. For anxiety prevention aimed at high risk adolescents, no short-term effect was found, nor at 12 months follow-up. Three to six months after the preventive intervention, symptoms of anxiety were significantly decreased. Although effects on depression and anxiety symptoms were small and temporary, current findings cautiously suggest that depression and anxiety prevention programs based on CBT might have small effects on mental health of adolescents. However, it also indicates that there is still much to be gained for prevention programs. Current findings and possibilities for future research are discussed in order to further

Microstructural Analysis of the Effects of Thermal Runaway on Li-Ion and Na-Ion Battery Electrodes

Energy Technology Data Exchange (ETDEWEB)

Finegan, Donal [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Robinson, James B. [University College London; Heenan, Thomas M. M. [University College London; Smith, Katherine [Sharp Laboratories of Europe; Kendrick, Emma [Sharp Laboratories of Europe; University College London; Brett, Daniel J. L. [University College London; Shearing, Paul R. [University College London

2017-12-06

Thermal runaway is a phenomenon that occurs due to self-sustaining reactions within batteries at elevated temperatures resulting in catastrophic failure. Here, the thermal runaway process is studied for a Li-ion and Na-ion pouch cells of similar energy density (10.5 Wh, 12 Wh, respectively) using accelerating rate calorimetry (ARC). Both cells were constructed with a z-fold configuration, with a standard shutdown separator in the Li-ion and a low-cost polypropylene (PP) separator in the Na-ion. Even with the shutdown separator, it is shown that the self-heating rate and rate of thermal runaway in Na-ion cells is significantly slower than that observed in Li-ion systems. The thermal runaway event initiates at a higher temperature in Na-ion cells. The effect of thermal runaway on the architecture of the cells is examined using X-ray microcomputed tomography, and scanning electron microscopy (SEM) is used to examine the failed electrodes of both cells. Finally, from examination of the respective electrodes, likely due to the carbonate solvent containing electrolyte, it is suggested that thermal runaway in Na-ion batteries (NIBs) occurs via a similar mechanism to that reported for Li-ion cells.

Instability connected with a beam of run-away electrons in the Tokamak TM-3

International Nuclear Information System (INIS)

Alikaev, V.V.; Razumova, K.A.; Sokolov, Yu.A.

The study of the instability of runaway electrons on the Tokamak TM-3 is continued. The longitudinal energy of runaway electrons that have undergone deceleration during instability is estimated from measurements of superhigh frequency radiation of plasma. A connection was found between the effect of a small fraction of energy protons (observed previously with a low plasma concentration) and the instability being studied. As instability develops, the longitudinal energy of runaway electrons is partially transformed to the transverse degree of freedom of these electrons and is partially transmitted to the basic plasma component

Empirical links between the local runaway greenhouse, super-greenhouse, and deep convection in Earth's tropics

Science.gov (United States)

Dewey, M. C.; Goldblatt, C.

2017-12-01

Energy balance requires that energy absorbed and emitted at the top of the atmosphere equal; this is maintained via the Planck feedback whereby outgoing longwave radiation (OLR) increases as surface temperature increases. There are two cases where this breaks down: the runaway greenhouse (known from planetary sciences theory) characterized by an asymptotic limit on OLR from moist atmospheres, and the super-greenhouse (known from tropical meteorology observations) where OLR decreases with surface temperature when the atmosphere is moist aloft. Here we show that the runaway greenhouse limit can be empirically observed and constrained in Earth's tropics, that the runaway and super-greenhouse occur as part of the same physical phenomenon, and that the transition through the super-greenhouse to a local runaway greenhouse is intimately linked to the onset of deep convection. A runaway greenhouse occurs when water vapour causes the troposphere to become optically thick to thermal radiation from the surface and a limit on OLR emerges as thermal emission is from a constant temperature level aloft. This limit is modelled as 282 W/m/m [Goldblatt et al, 2013]. Using satellite data from Earth's tropics, we find an empirical value of this limit of 280 W/m/m, in excellent agreement with the model.A column transitioning to a runaway greenhouse typically overshoots the runaway limit and then OLR decreases with increasing surface temperature until the runaway limit is reached after which OLR remains constant. The term super-greenhouse effect (SGE) has been used to describe OLR decreasing with surface warming, observed in these satellite measurements. We show the SGE is one and the same as the transition to a local runaway greenhouse, and represents a fundamental shift in the radiation response of the earth system, rather than simply an extension of water vapour feedback. This transition via SGE from an optically thin to optically thick troposphere is facilitated by enhanced

Efficacy of Adolescent Suicide Prevention E-Learning Modules for Gatekeepers: A Randomized Controlled Trial.

Science.gov (United States)

Ghoncheh, Rezvan; Gould, Madelyn S; Twisk, Jos Wr; Kerkhof, Ad Jfm; Koot, Hans M

2016-01-29

Face-to-face gatekeeper training can be an effective strategy in the enhancement of gatekeepers' knowledge and self-efficacy in adolescent suicide prevention. However, barriers related to access (eg, time, resources) may hamper participation in face-to-face training sessions. The transition to a Web-based setting could address obstacles associated with face-to-face gatekeeper training. Although Web-based suicide prevention training targeting adolescents exists, so far no randomized controlled trials (RCTs) have been conducted to investigate their efficacy. This RCT study investigated the efficacy of a Web-based adolescent suicide prevention program entitled Mental Health Online, which aimed to improve the knowledge and self-confidence of gatekeepers working with adolescents (12-20 years old). The program consisted of 8 short e-learning modules each capturing an important aspect of the process of early recognition, guidance, and referral of suicidal adolescents, alongside additional information on the topic of (adolescent) suicide prevention. A total of 190 gatekeepers (ages 21 to 62 years) participated in this study and were randomized to either the experimental group or waitlist control group. The intervention was not masked. Participants from both groups completed 3 Web-based assessments (pretest, posttest, and 3-month follow-up). The outcome measures of this study were actual knowledge, and participants' ratings of perceived knowledge and perceived self-confidence using questionnaires developed specifically for this study. The actual knowledge, perceived knowledge, and perceived self-confidence of gatekeepers in the experimental group improved significantly compared to those in the waitlist control group at posttest, and the effects remained significant at 3-month follow-up. The overall effect sizes were 0.76, 1.20, and 1.02, respectively, across assessments. The findings of this study indicate that Web-based suicide prevention e-learning modules can be an

Effects of discharge cleaning on the production of runaway electrons in TORTUS tokamak

International Nuclear Information System (INIS)

Cross, R.C.; Liu, J.R.; Giannone, L.

1983-01-01

Experimental results are presented on the production of runaway electrons as a function of wall cleanliness in the TORTUS tokamak. When the walls are clean, the production rate decreases as the filling pressure increases. When the walls are contaminated by oxygen, the production rate can increase when the filling pressure is increased, owing to the production of water vapour during tokamak discharges. These results resolve the differences reported in the literature on the production of runaways as a function of filling pressure. It is also observed that the runaway electron instability seen in other devices is suppressed when the walls are discharge-cleaned. (author)

On the relativistic large-angle electron collision operator for runaway avalanches in plasmas

Science.gov (United States)

Embréus, O.; Stahl, A.; Fülöp, T.

2018-02-01

Large-angle Coulomb collisions lead to an avalanching generation of runaway electrons in a plasma. We present the first fully conservative large-angle collision operator, derived from the relativistic Boltzmann operator. The relation to previous models for large-angle collisions is investigated, and their validity assessed. We present a form of the generalized collision operator which is suitable for implementation in a numerical kinetic equation solver, and demonstrate the effect on the runaway-electron growth rate. Finally we consider the reverse avalanche effect, where runaways are slowed down by large-angle collisions, and show that the choice of operator is important if the electric field is close to the avalanche threshold.

Measurement of runaway electron energy distribution function during high-Z gas injection into runaway electron plateaus in DIII-Da)

Energy Technology Data Exchange (ETDEWEB)

Hollmann, E. M. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA; Parks, P. B. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Commaux, N. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, USA; Eidietis, N. W. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Moyer, R. A. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA; Shiraki, D. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37831, USA; Austin, M. E. [Institute for Fusion Studies, University of Texas—Austin, 2100 San Jacinto Blvd, Austin, Texas 78712, USA; Lasnier, C. J. [Lawrence Livermore National Laboratory, 7000 East Ave, Livermore, California 94550, USA; Paz-Soldan, C. [General Atomics, PO Box 85608, San Diego, California 92186, USA; Rudakov, D. L. [University of California—San Diego, 9500 Gilman Dr., La Jolla, California 92093, USA

2015-05-01

The evolution of the runaway electron (RE) energy distribution function fεfε during massive gas injection into centered post-disruption runaway electron plateaus has been reconstructed. Overall, fεfε is found to be much more skewed toward low energy than predicted by avalanche theory. The reconstructions also indicate that the RE pitch angle θ is not uniform, but tends to be large at low energies and small θ ~0.1–0.2 at high energies. Overall power loss from the RE plateau appears to be dominated by collisions with background free and bound electrons, leading to line radiation. However, the drag on the plasma current appears to be dominated by collisions with impurity ions in most cases. Synchrotron emission appears not to be significant for overall RE energy dissipation but may be important for limiting the peak RE energy.

Measurement of runaway electron energy distribution function during high-Z gas injection into runaway electron plateaus in DIII-D

International Nuclear Information System (INIS)

Hollmann, E. M.; Moyer, R. A.; Rudakov, D. L.; Parks, P. B.; Eidietis, N. W.; Paz-Soldan, C.; Commaux, N.; Shiraki, D.; Austin, M. E.; Lasnier, C. J.

2015-01-01

The evolution of the runaway electron (RE) energy distribution function f ε during massive gas injection into centered post-disruption runaway electron plateaus has been reconstructed. Overall, f ε is found to be much more skewed toward low energy than predicted by avalanche theory. The reconstructions also indicate that the RE pitch angle θ is not uniform, but tends to be large at low energies and small θ ∼ 0.1–0.2 at high energies. Overall power loss from the RE plateau appears to be dominated by collisions with background free and bound electrons, leading to line radiation. However, the drag on the plasma current appears to be dominated by collisions with impurity ions in most cases. Synchrotron emission appears not to be significant for overall RE energy dissipation but may be important for limiting the peak RE energy

On the origin of the hypervelocity runaway star HD 271791

Science.gov (United States)

Gvaramadze, V. V.

2010-01-01

We discuss the origin of the early-B-type runaway star HD 271791 and show that its extremely high velocity (≃530 - 920km s-1) cannot be explained within the framework of the binary-supernova ejection scenario. Instead, we suggest that HD 271791 attained its peculiar velocity in the course of a strong dynamical encounter between two hard, massive binaries or through an exchange encounter between a hard, massive binary and a very massive star, formed through runaway mergers of ordinary massive stars in the dense core of a young massive star cluster.

Investigating the effects of counseling programs on runaway youth

Directory of Open Access Journals (Sweden)

Mohammad Reza Iravani

2014-04-01

Full Text Available This paper presents an empirical investigation to study the effects of counseling programs on reducing the runaway youth in Iran. The study selects a sample of 30 students and divides them into two groups of control and experiment. The first group is kept under eight sessions of social skills training and a questionnaire consists of various questions including confidence items is distributed among both groups after the training ends. The implementation of Kolmogorov-Smirnov has revealed that both pre and post-test data are normally distributed. In addition, the result of ANOVA test has revealed that training program could significantly improve runaway youth’s confidence.

Thermonuclear Runaway model

International Nuclear Information System (INIS)

Sparks, W.M.; Kutter, G.S.; Starrfield, S.; Truran, J.W.

1989-01-01

The nova outburst requires an energy source that is energetic enough to eject material and is able to recur. The Thermonuclear Runaway (TNR) model, coupled with the binary nature of nova systems satisfies these conditions. The white dwarf/red dwarf binary nature of novae was first recognized as a necessary conditions by Kraft. The small separation characteristic of novae systems allows the cool, red secondary to overflow is Roche lobe. In the absence of strong, funneling magnetic fields, the angular momentum of this material prevents it from falling directly onto the primary, and it first forms a disk around the white dwarf. This material is eventually accreted from the disk onto the white dwarf. As the thickness of this hydrogen-rich layer increases, the degenerate matter at the base reaches a temperature that is high enough to initiate thermonuclear fusion of hydrogen. Thermonuclear energy release increases the temperature which in turn increases the energy generation rate. Because the material is degenerate, the pressure does not increase with temperature, which normally allows a star to adjust itself to a steady nuclear burning rate. Thus the temperature and nuclear energy generation increase and a TNR results. When the temperature reaches the Fermi temperature, degeneracy is lifted and the rapid pressure increase causes material expansion. The hydrogen-rich material either is ejected or consumed by nuclear burning, and the white dwarf returns to its pre-outburst state. The external source of hydrogen fuel from the secondary allows the while process to repeat. 43 refs., 8 figs

School-Based Drug Prevention among At-Risk Adolescents: Effects of ALERT Plus

Science.gov (United States)

Longshore, Douglas; Ellickson, Phyllis L.; McCaffrey, Daniel F.; St. Clair, Patricia A.

2007-01-01

In a recent randomized field trial, Ellickson et al. found the Project ALERT drug prevention curriculum curbed alcohol misuse and tobacco and marijuana use among eighth-grade adolescents. This article reports effects among ninth-grade at-risk adolescents. Comparisons between at-risk girls in ALERT Plus schools (basic curriculum extended to ninth…

History matters: childhood weight trajectories as a basis for planning community-based obesity prevention to adolescents.

Science.gov (United States)

Ekberg, J; Angbratt, M; Valter, L; Nordvall, M; Timpka, T

2012-04-01

To use epidemiological data and a standardized economic model to compare projected costs for obesity prevention in late adolescence accrued using a cross-sectional weight classification for selecting adolescents at age 15 years compared with a longitudinal classification. All children born in a Swedish county (population 440 000) in 1991 who participated in all regular measurements of height and weight at ages 5, 10 and 15 years (n=4312) were included in the study. The selection strategies were compared by calculating the projected financial load resulting from supply of obesity prevention services from providers at all levels in the health care system. The difference in marginal cost per 1000 children was used as the primary end point for the analyses. Using the cross-sectional selection strategy, 3.8% of adolescents at age 15 years were selected for evaluation by a pediatric specialist, and 96.2% were chosen for population-based interventions. In the trajectory-based strategy, 2.4% of the adolescents were selected for intensive pediatric care, 1.4% for individual clinical interventions in primary health care, 14.0% for individual primary obesity prevention using the Internet and 82.1% for population-based interventions. Costs for the cross-sectional selection strategy were projected to USD463 581 per 1000 adolescents and for the trajectory-based strategy were USD 302 016 per 1000 adolescents. Using projections from epidemiological data, we found that by basing the selection of adolescents for obesity prevention on weight trajectories, the load on highly specialized pediatric care can be reduced by one-third and total health service costs for obesity management among adolescents reduced by one-third. Before use in policies and prevention program planning, our findings warrant confirmation in prospective cost-benefit studies.

Psychological and pedagogical conditions for the preventions of deviant behavior among adolescents

Directory of Open Access Journals (Sweden)

Vist N.V.

2017-01-01

Full Text Available this article focuses on such a highly relevant subject as the prevention and correction of deviant behavior in the adolescent environment. The study revealed the main vectors for the development of the modern science of deviant behavior, identified the main causes of deviations and carried out a comparative analysis of the work on the prevention of deviant behavior in the CIS countries and abroad. This paper proved that the key factor in the prevention and correction of deviant behavior should be, firstly, the family as the primary and the most important institution of identity formation, and secondly, the pedagogically controlled environment of educational institutions serving as a condition for socialization and personal development for children and adolescents.

Neuromuscular exercises prevent severe knee injury in adolescent team handball players.

Science.gov (United States)

Achenbach, Leonard; Krutsch, Volker; Weber, Johannes; Nerlich, Michael; Luig, Patrick; Loose, Oliver; Angele, Peter; Krutsch, Werner

2017-10-20

Team handball is associated with a high risk of severe knee injury that needs to be reduced, particularly at the youth level. The purpose of this study was to show how an injury-prevention programme effectively reduces severe knee injury in adolescent team handball players. Of 23 adolescent handball teams of both sexes, 13 were randomly allocated into the intervention group (168 players) and 10 into the control group (111 players). Players of the intervention group regularly participated in an injury-prevention programme for one season. Handball exposure and sustained injuries were documented for both groups on a monthly basis. The primary outcome parameter of the injury-prevention programme was the incidence of severe knee injury. Of the 279 included players, 68 (24%) sustained 82 injuries yielding an overall incidence of 1.85 injuries per 1000 h handball exposure (intervention group: 50 injuries/incidence: 1.90/1000 h; control group: 32 injuries/incidence: 1.78/1000 h). Knee injury was the second most frequent injury in adolescent team handball. The primary outcome parameter, severe knee injury occurred significantly more often in the control group [mean age (SD) 15.1 (1.0), injury incidence 0.33/1000 h] than in the intervention group [mean age (SD) 14.9 (0.9), injury incidence 0.04/1000 h]. The odds ratio was 0.11 (95% CI 0.01-0.90), p = 0.019. Other injuries to the lower extremities showed no significant difference between the two groups. Frequent neuromuscular exercises prevent severe knee injury in adolescent team handball players and should thus be included in the practical routine as well as in the education of team coaches.

Predicted space motions for hypervelocity and runaway stars: proper motions and radial velocities for the Gaia Era

Energy Technology Data Exchange (ETDEWEB)

Kenyon, Scott J.; Brown, Warren R.; Geller, Margaret J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Bromley, Benjamin C., E-mail: skenyon@cfa.harvard.edu, E-mail: wbrown@cfa.harvard.edu, E-mail: mgeller@cfa.harvard.edu, E-mail: bromley@physics.utah.edu [Department of Physics, University of Utah, 115 S 1400 E, Rm 201, Salt Lake City, UT 84112 (United States)

2014-10-01

We predict the distinctive three-dimensional space motions of hypervelocity stars (HVSs) and runaway stars moving in a realistic Galactic potential. For nearby stars with distances less than 10 kpc, unbound stars are rare; proper motions alone rarely isolate bound HVSs and runaways from indigenous halo stars. At large distances of 20-100 kpc, unbound HVSs are much more common than runaways; radial velocities easily distinguish both from indigenous halo stars. Comparisons of the predictions with existing observations are encouraging. Although the models fail to match observations of solar-type HVS candidates from SEGUE, they agree well with data for B-type HVS and runaways from other surveys. Complete samples of g ≲ 20 stars with Gaia should provide clear tests of formation models for HVSs and runaways and will enable accurate probes of the shape of the Galactic potential.

Thermal Runaways in LHC Interconnections: Experiments

CERN Document Server

Willering, G P; Bottura, L; Scheuerlein, C; Verweij, A P

2011-01-01

The incident in the LHC in September 2008 occurred in an interconnection between two magnets of the 13 kA dipole circuit. This event was traced to a defect in one of the soldered joints between two superconducting cables stabilized by a copper busbar. Further investigation revealed defective joints of other types. A combination of (1) a poor contact between the superconducting cable and the copper stabilizer and (2) an electrical discontinuity in the stabilizer at the level of the connection can lead to an unprotected quench of the busbar. Once the heating power in the unprotected superconducting cable exceeds the heat removal capacity a thermal run-away occurs, resulting in a fast melt-down of the non-stabilized cable. We have performed a thorough investigation of the conditions upon which a thermal run-away in the defect can occur. To this aim, we have prepared heavily instrumented samples with well-defined and controlled defects. In this paper we describe the experiment, and the analysis of the data, and w...

Computeen: A Randomized Trial of a Preventive Computer and Psychosocial Skills Curriculum for At-Risk Adolescents

Science.gov (United States)

Lang, Jason M.; Waterman, Jill; Baker, Bruce L.

2009-01-01

Computeen, a preventive technology and psychosocial skills development program for at-risk adolescents, was designed to improve computer skills, self-esteem, and school attitudes, and reduce behavior problems, by combining elements of community-based and empirically supported prevention programs. Fifty-five mostly Latino adolescents from 12 to 16…

On the physics of runaway particles in JET and MAST

International Nuclear Information System (INIS)

Helander, P.; Akers, R.J.; Gimblett, C.G.; Tournianski, M.R.; Byrom, C.; Eriksson, L.-G.; Andersson, F.

2003-01-01

This paper explores the physics of runaway particles observed in MAST and JET. During internal reconnection events in MAST, it is observed that the ion distribution function, as measured by a neutral-particle analyser, develops a high-energy tail, which subsequently decays on the time scale of collisional slowing down. These observations are explained in terms of runaway ion acceleration in the electric field induced by the reconnection - a phenomenon predicted theoretically by Furth and Rutherford in 1972 but not commonly noted in tokamaks. In JET, long-lived post-disruption currents carried by runaway electrons have been observed to decay on a time scale of 1-2 s. A relativistic kinetic theory is developed to explain this decay as a consequence of the combined action of Coulomb collisions and synchrotron radiation emission. It is also pointed out that substantial electron-positron pair production should occur in such discharges, which have also been made more recently on JT-60U. In fact, tokamaks may be the largest positron repositories made by man. (author)

Li-ion battery thermal runaway suppression system using microchannel coolers and refrigerant injections

Science.gov (United States)

Bandhauer, Todd M.; Farmer, Joseph C.

2016-11-08

A battery management system with thermally integrated fire suppression includes a multiplicity of individual battery cells in a housing; a multiplicity of cooling passages in the housing within or between the multiplicity of individual battery cells; a multiplicity of sensors operably connected to the individual battery cells, the sensors adapted to detect a thermal runaway event related to one or more of the multiplicity of individual battery cells; and a management system adapted to inject coolant into at least one of the multiplicity of cooling passages upon the detection of the thermal runaway event by the any one of the multiplicity of sensors, so that the thermal runaway event is rapidly quenched.

Parent-based interventions for preventing or reducing adolescent substance use - A systematic literature review.

Science.gov (United States)

Kuntsche, Sandra; Kuntsche, Emmanuel

2016-04-01

Despite the increasing relevance of peers, parents remain important socializing agents for their adolescent children and are therefore promising agents for inclusion in prevention or intervention programs. This systematic review provides an overview of the effectiveness of parent-based programs in preventing, curbing or reducing substance use (i.e. alcohol, tobacco and cannabis) among 10 to 18-year-olds. The databases PubMed, PsychInfo, Eric and Google Scholar were used to identify randomized trials published within the past 12years evaluating effects on adolescent substance use. Of the 653 identified in the first screening, 39 publications dealing with 13 programs were included. Results reveal desirable effects of parenting measures such as rule-setting, monitoring and parent-child communication. There was also some evidence in terms of preventing, curbing or reducing adolescent substance use. However, this appears to depend particularly on the age group of the adolescents in question, the kind of parents included and the intensity of the program. To conclude, the results of this systematic review underline the importance of including parents in programs aiming to impede initiation of substance use or curb or reduce already existing substance use in adolescence. Copyright © 2016 Elsevier Ltd. All rights reserved.

Temporal and spatial evolution of runaway electrons at the instability moments in Damavand tokamak

Energy Technology Data Exchange (ETDEWEB)

Pourshahab, B. [Department of Nuclear Engineering, Faculty of Advance Sciences and Technologies, University of Isfahan, P.O. Box 81747-73441, Isfahan (Iran, Islamic Republic of); Abdi, M. R. [Department of Physics, Faculty of Science, University of Isfahan, P.O. Box 81747-73441, Isfahan (Iran, Islamic Republic of); Sadighzadeh, A.; Rasouli, C. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of)

2016-07-15

The time and position behavior of runaway electrons at the Parail–Pogutse instability moments has been investigated using experimental observations in plasma current, loop voltage, the Hard X-ray (HXR) radiations, and 18 poloidal pickup coils signals received by data acquisition system simultaneously. The conditional average sampling (CAS) method was used to analyze the output data. Moreover, a filament current code was modified to study the runaway electrons beam movement in the event of instabilities. The results display a rapid drift of runaway beam toward the inner wall of the vacuum vessel and the collision with the wall components at the instability moments. The existence of the collisions in these experiments is evident in the HXR bursts which are considered as the main trigger for CAS Analysis. Also, the variation of HXR bursts with the toroidal magnetic field shows that the hard X-ray bursts drop with increase in the toroidal magnetic field and runaway electrons confinement quality.

78 FR 64153 - Direct Certification and Certification of Homeless, Migrant and Runaway Children for Free School...

Science.gov (United States)

2013-10-28

...-0001] RIN 0584-AD60 Direct Certification and Certification of Homeless, Migrant and Runaway Children... interim rule entitled Direct Certification and Certification of Homeless, Migrant and Runaway Children for...

Evaluation of runaway-electron effects on plasma-facing components for NET

Science.gov (United States)

Bolt, H.; Calén, H.

1991-03-01

Runaway electrons which are generated during disruptions can cause serious damage to plasma facing components in a next generation device like NET. A study was performed to quantify the response of NET plasma facing components to runaway-electron impact. For the determination of the energy deposition in the component materials Monte Carlo computations were performed. Since the subsurface metal structures can be strongly heated under runaway-electron impact from the computed results damage threshold values for the thermal excursions were derived. These damage thresholds are strongly dependent on the materials selection and the component design. For a carbonmolybdenum divertor with 10 and 20 mm carbon armour thickness and 1 degree electron incidence the damage thresholds are 100 MJ/m 2 and 220 MJ/m 2. The thresholds for a carbon-copper divertor under the same conditions are about 50% lower. On the first wall damage is anticipated for energy depositions above 180 MJ/m 2.

A Randomized Depression Prevention Trial Comparing Interpersonal Psychotherapy--Adolescent Skills Training to Group Counseling in Schools.

Science.gov (United States)

Young, Jami F; Benas, Jessica S; Schueler, Christie M; Gallop, Robert; Gillham, Jane E; Mufson, Laura

2016-04-01

Given the rise in depression disorders in adolescence, it is important to develop and study depression prevention programs for this age group. The current study examined the efficacy of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST), a group prevention program for adolescent depression, in comparison to group programs that are typically delivered in school settings. In this indicated prevention trial, 186 adolescents with elevated depression symptoms were randomized to receive IPT-AST delivered by research staff or group counseling (GC) delivered by school counselors. Hierarchical linear modeling examined differences in rates of change in depressive symptoms and overall functioning from baseline to the 6-month follow-up assessment. Cox regression compared rates of depression diagnoses. Adolescents in IPT-AST showed significantly greater improvements in self-reported depressive symptoms and evaluator-rated overall functioning than GC adolescents from baseline to the 6-month follow-up. However, there were no significant differences between the two conditions in onset of depression diagnoses. Although both intervention conditions demonstrated significant improvements in depressive symptoms and overall functioning, results indicate that IPT-AST has modest benefits over groups run by school counselors which were matched on frequency and duration of sessions. In particular, IPT-AST outperformed GC in reduction of depressive symptoms and improvements in overall functioning. These findings point to the clinical utility of this depression prevention program, at least in the short-term. Additional follow-up is needed to determine the long-term effects of IPT-AST, relative to GC, particularly in preventing depression onset.

A Randomized Depression Prevention Trial Comparing Interpersonal Psychotherapy—Adolescent Skills Training to Group Counseling in Schools

Science.gov (United States)

Benas, Jessica S.; Schueler, Christie M.; Gallop, Robert; Gillham, Jane E.; Mufson, Laura

2017-01-01

Given the rise in depression disorders in adolescence, it is important to develop and study depression prevention programs for this age group. The current study examined the efficacy of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST), a group prevention program for adolescent depression, in comparison to group programs that are typically delivered in school settings. In this indicated prevention trial, 186 adolescents with elevated depression symptoms were randomized to receive IPT-AST delivered by research staff or group counseling (GC) delivered by school counselors. Hierarchical linear modeling examined differences in rates of change in depressive symptoms and overall functioning from baseline to the 6-month follow-up assessment. Cox regression compared rates of depression diagnoses. Adolescents in IPT-AST showed significantly greater improvements in self-reported depressive symptoms and evaluator-rated overall functioning than GC adolescents from baseline to the 6-month follow-up. However, there were no significant differences between the two conditions in onset of depression diagnoses. Although both intervention conditions demonstrated significant improvements in depressive symptoms and overall functioning, results indicate that IPT-AST has modest benefits over groups run by school counselors which were matched on frequency and duration of sessions. In particular, IPT-AST outperformed GC in reduction of depressive symptoms and improvements in overall functioning. These findings point to the clinical utility of this depression prevention program, at least in the short-term. Additional follow-up is needed to determine the long-term effects of IPT-AST, relative to GC, particularly in preventing depression onset. PMID:26638219

An analysis of family-school collaboration in preventing adolescent ...

African Journals Online (AJOL)

The purpose of this article is to describe how school staff members, learners and parents collaborate to prevent adolescent learner violence in two different urban secondary schools. The increase in acts of interpersonal learner violence has a destructive effect on the safe and positive development of young people.

Development and formative evaluation of a family-centred adolescent HIV prevention programme in South Africa.

Science.gov (United States)

Visser, Maretha; Thurman, Tonya R; Spyrelis, Alexandra; Taylor, Tory M; Nice, Johanna K; Finestone, Michelle

2018-03-06

Preventing HIV among young people is critical to achieving and sustaining global epidemic control. Evidence from Western settings suggests that family-centred prevention interventions may be associated with greater reductions in risk behaviour than standard adolescent-only models. Despite this, family-centred models for adolescent HIV prevention are nearly non-existent in South Africa - home to more people living with HIV than any other country. This paper describes the development and formative evaluation of one such intervention: an evidence-informed, locally relevant, adolescent prevention intervention engaging caregivers as co-participants. The programme, originally consisting of 19 sessions for caregivers and 14 for adolescents, was piloted with 12 groups of caregiver-adolescent dyads by community-based organizations (CBOs) in KwaZulu-Natal and Gauteng provinces. Literature and expert reviews were employed in the development process, and evaluation methods included analysis of attendance records, session-level fidelity checklists and facilitator feedback forms collected during the programme pilot. Facilitator focus group discussions and an implementer programme workshop were also held. Results highlighted the need to enhance training content related to cognitive behavioural theory and group management techniques, as well as increase the cultural relevance of activities in the curriculum. Participant attendance challenges were also identified, leading to a shortened and simplified session set. Findings overall were used to finalize materials and guidance for a revised 14-week group programme consisting of individual and joint sessions for adolescents and their caregivers, which may be implemented by community-based facilitators in other settings. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adolescent environmental enrichment prevents behavioral and physiological sequelae of adolescent chronic stress in female (but not male) rats.

Science.gov (United States)

Smith, Brittany L; Morano, Rachel L; Ulrich-Lai, Yvonne M; Myers, Brent; Solomon, Matia B; Herman, James P

2017-11-22

The late adolescent period is characterized by marked neurodevelopmental and endocrine fluctuations in the transition to early adulthood. Adolescents are highly responsive to the external environment, which enhances their ability to adapt and recover from challenges when given nurturing influences, but also makes them vulnerable to aberrant development when exposed to prolonged adverse situations. Female rats are particularly sensitive to the effects of chronic stress in adolescence, which manifests as passive coping strategies and blunted hypothalamo-pituitary adrenocortical (HPA) stress responses in adulthood. We sought to intervene by exposing adolescent rats to environmental enrichment (EE) immediately prior to and during chronic stress, hypothesizing that EE would minimize or prevent the long-term effects of stress that emerge in adult females. To test this, we exposed male and female rats to EE on postnatal days (PND) 33-60 and implemented chronic variable stress (CVS) on PND 40-60. CVS consisted of twice-daily unpredictable stressors. Experimental groups included: CVS/unenriched, unstressed/EE, CVS/EE and unstressed/unenriched (n = 10 of each sex/group). In adulthood, we measured behavior in the open field test and forced swim test (FST) and collected blood samples following the FST. We found that environmental enrichment given during the adolescent period prevented the chronic stress-induced transition to passive coping in the FST and reversed decreases in peak adrenocortical responsiveness observed in adult females. Adolescent enrichment had little to no effect on males or unstressed females tested in adulthood, indicating that beneficial effects are specific to females that were exposed to chronic stress.

African-American and Latino Parents’ Attitudes and Beliefs Regarding Adolescent Fighting and Its Prevention

Science.gov (United States)

Chen, RuiJun; Flores, Glenn; Shetgiri, Rashmi

2015-01-01

Adolescent fighting affects 25% of youth, with the highest rates among African-Americans and Latinos but little is known about parental views on youth fighting. The purpose of this study was to examine African-American and Latino parents’ perspectives on adolescent fighting and methods to prevent fighting. We conducted four focus groups with parents of African-American and Latino urban adolescents. Focus groups were stratified by race/ethnicity and fighting status. Groups were audiotaped, transcribed, and analyzed by three independent coders using thematic content analysis. Seventy-six percent of the 17 participants were female. Latino parents condoned fighting only as a last resort, and taught children about consequences of fighting, emotional regulation, and non-violent conflict-resolution strategies. African-American parents endorsed teaching non-violent strategies, but expressed some doubts about their effectiveness. African-American parents also suggested corporal punishment, but acknowledged that this may not be an optimal long-term strategy. Positive role modeling and involvement by teachers and other adults were cited as having important roles in fighting prevention. Suggested interventions included teaching adolescents non-violent conflict-resolution skills, anger management, and alternatives to fighting. Parents recommended that violence prevention programs incorporate the experiences of former fighters and be tailored to community needs. Study findings suggest that youth violence-prevention programs may benefit from addressing parental attitudes towards fighting and parent-child communication about fighting, teaching adolescents non-violent conflict-resolution skills, and tailoring programs by race/ethnicity. Promoting positive modeling and involvement by teachers and other adults also may be beneficial. PMID:27186064

African-American and Latino Parents' Attitudes and Beliefs Regarding Adolescent Fighting and Its Prevention.

Science.gov (United States)

Chen, RuiJun; Flores, Glenn; Shetgiri, Rashmi

2016-06-01

Adolescent fighting affects 25% of youth, with the highest rates among African-Americans and Latinos but little is known about parental views on youth fighting. The purpose of this study was to examine African-American and Latino parents' perspectives on adolescent fighting and methods to prevent fighting. We conducted four focus groups with parents of African-American and Latino urban adolescents. Focus groups were stratified by race/ethnicity and fighting status. Groups were audiotaped, transcribed, and analyzed by three independent coders using thematic content analysis. Seventy-six percent of the 17 participants were female. Latino parents condoned fighting only as a last resort, and taught children about consequences of fighting, emotional regulation, and non-violent conflict-resolution strategies. African-American parents endorsed teaching non-violent strategies, but expressed some doubts about their effectiveness. African-American parents also suggested corporal punishment, but acknowledged that this may not be an optimal long-term strategy. Positive role modeling and involvement by teachers and other adults were cited as having important roles in fighting prevention. Suggested interventions included teaching adolescents non-violent conflict-resolution skills, anger management, and alternatives to fighting. Parents recommended that violence prevention programs incorporate the experiences of former fighters and be tailored to community needs. Study findings suggest that youth violence-prevention programs may benefit from addressing parental attitudes towards fighting and parent-child communication about fighting, teaching adolescents non-violent conflict-resolution skills, and tailoring programs by race/ethnicity. Promoting positive modeling and involvement by teachers and other adults also may be beneficial.

Parameters of an avalanche of runaway electrons in air under atmospheric pressure

Science.gov (United States)

Oreshkin, E. V.

2018-01-01

The features of runaway-electron avalanches developing in air under atmospheric pressures are investigated in the framework of a three-dimensional numerical simulation. The simulation results indicate that an avalanche of this type can be characterized, besides the time and length of its exponential growth, by the propagation velocity and by the average kinetic energy of the runaway electrons. It is shown that these parameters obey the similarity laws applied to gas discharges.

Use of Multimedia or Mobile Devices By Adolescents for Health Promotion and Disease Prevention: A Literature Review.

Science.gov (United States)

Geckle, Joan

2016-01-01

The purpose of this literature review is to summarize studies of the use of multimedia technology by adolescents to engage in their healthcare promotion and disease prevention. A systematic literature review of relevant peer-reviewed research published between 2009 and 2014 was performed. The 16 articles reviewed were a combination of quantitative and mixed-method methodology based on the efficacy of multimedia, mobile technology, Short Messaging Services (SMS) texting, and social networking (e.g., Facebook®), to engage adolescents ages 10 to 20 years in health promotion and disease prevention. Although adolescents have high attrition rates in the studies, they demonstrated advantages in using SMS texting features and social networking, especially the chat function, in relation to health promotion and disease prevention. Some small gains were noticed in health promotion and disease prevention in the majority of the studies, though some were not significant due to attrition. Additional research, especially nursing research, is necessary. Mobile and multimedia technology allows for a promising correlation between adolescents and increased healthcare knowledge, health promotion, and disease prevention.

Runaway electrons in the TRIAM-1 tokamak

International Nuclear Information System (INIS)

Satoh, Takemichi; Nakamura, Kazuo; Toi, Kazuo; Nakamura, Yukio; Hiraki, Naoji

1981-01-01

Pulse height analysis of soft X-rays is carried out in the TRIAM-1 tokamak. The electron temperatures determined from the soft X-ray spectrum agree well with those from Thomson scattering. It is observed that low-energy runaway (slideaway) electrons appear in the high-current-density discharges. (author)

Runaway electrons in the TRIAM-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Satoh, T; Nakamura, K; Toi, K; Nakamura, Y; Hiraki, N [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-09-01

Pulse height analysis of soft X-rays is carried out in the TRIAM-1 tokamak. The electron temperatures determined from the soft X-ray spectrum agree well with those from Thomson scattering. It is observed that low-energy runaway (slideaway) electrons appear in the high-current-density discharges.

76 FR 30368 - Announcement of the Publication of Funding Opportunity Announcements under the Runaway and...

Science.gov (United States)

2011-05-25

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Administration for Children and Families Announcement of the Publication of Funding Opportunity Announcements under the Runaway and Homeless Youth Act AGENCY... (SOP) are now available for application. CFDA Number: 93.623, 93.557. Statutory Authority: Runaway and...

A Theater-Based Approach to Primary Prevention of Sexual Behavior for Early Adolescents

Science.gov (United States)

Lieberman, Lisa D.; Berlin, Cydelle; Palen, Lori-Ann; Ashley, Olivia Silber

2012-01-01

Early adolescence is a crucial period for preventing teen pregnancy and sexually transmitted infections. This study evaluated STAR LO, a theater-based intervention designed to affect antecedents of sexual activity among urban early adolescents (N = 1,143). Public elementary/middle schools received the intervention or served as a wait-listed…

High-velocity runaway stars from three-body encounters

Science.gov (United States)

Gvaramadze, V. V.; Gualandris, A.; Portegies Zwart, S.

2010-01-01

We performed numerical simulations of dynamical encounters between hard, massive binaries and a very massive star (VMS; formed through runaway mergers of ordinary stars in the dense core of a young massive star cluster) to explore the hypothesis that this dynamical process could be responsible for the origin of high-velocity (≥ 200 - 400 km s-1) early or late B-type stars. We estimated the typical velocities produced in encounters between very tight massive binaries and VMSs (of mass of ≥ 200 M⊙) and found that about 3 - 4% of all encounters produce velocities ≥ 400 km s-1, while in about 2% of encounters the escapers attain velocities exceeding the Milky Ways's escape velocity. We therefore argue that the origin of high-velocity (≥ 200 - 400 km s-1) runaway stars and at least some so-called hypervelocity stars could be associated with dynamical encounters between the tightest massive binaries and VMSs formed in the cores of star clusters. We also simulated dynamical encounters between tight massive binaries and single ordinary 50 - 100 M⊙ stars. We found that from 1 to ≃ 4% of these encounters can produce runaway stars with velocities of ≥ 300 - 400 km s-1 (typical of the bound population of high-velocity halo B-type stars) and occasionally (in less than 1% of encounters) produce hypervelocity (≥ 700 km s-1) late B-type escapers.

[Electronic media in obesity prevention in childhood and adolescence].

Science.gov (United States)

Weihrauch-Blüher, Susann; Koormann, Stefanie; Brauchmann, Jana; Wiegand, Susanna

2016-11-01

The increasing prevalence of childhood obesity is - amongst other factors - due to changed leisure time habits with decreased physical activity and increased media consumption. However, electronic media such as tablets and smartphones might also provide a novel intervention approach to prevent obesity in childhood and adolescence. A summary of interventions applying electronic media to prevent childhood obesity is provided to investigate short term effects as well as long term results of these interventions. A systematic literature search was performed in PubMed/Web of Science to identify randomized and/or controlled studies that have investigated the efficacy of electronic media for obesity prevention below the age of 18. A total of 909 studies were identified, and 88 studies were included in the analysis. Active video games did increase physical activity compared to inactive games when applied within a peer group. Interventions via telephone had positive effects on certain lifestyle-relevant behaviours. Interventions via mobile were shown to decrease dropout rates by sending regular SMS messages. To date, interventions via smartphones are scarce for adolescents; however, they might improve cardiorespiratory fitness. The results from internet-based interventions showed a trend towards positive effects on lifestyle-relevant behaviors. The combination of different electronic media did not show superior results compared to interventions with only one medium. Interventions via TV, DVD or video-based interventions may increase physical activity when offered as an incentive, however, effects on weight status were not observed. Children and adolescents currently grow up in a technology- and media-rich society with computers, tablets, smartphones, etc. used daily. Thus, interventions applying electronic media to prevent childhood obesity are contemporary. Available studies applying electronic media are however heterogeneous in terms of applied medium and duration

Positive Prevention: Successful Approaches To Preventing Youthful Drug and Alcohol Use [and] La Prevencion Positiva: Metodos que han tenido exito en la prevencion del uso de drogas y alcohol entre la juventud.

Science.gov (United States)

American Association of School Administrators, Arlington, VA.

The United States has the highest rate of youthful drug abuse of any industrialized country in the world. There is a growing awareness that drug and alcohol use are closely connected to other problems such as teenage suicide, adolescent pregnancy, traffic fatalities, juvenile delinquency, poor school performance, runaways, and dropouts. Youthful…

Stochastic runaway of dynamical systems

International Nuclear Information System (INIS)

Pfirsch, D.; Graeff, P.

1984-10-01

One-dimensional, stochastic, dynamical systems are well studied with respect to their stability properties. Less is known for the higher dimensional case. This paper derives sufficient and necessary criteria for the asymptotic divergence of the entropy (runaway) and sufficient ones for the moments of n-dimensional, stochastic, dynamical systems. The crucial implication is the incompressibility of their flow defined by the equations of motion in configuration space. Two possible extensions to compressible flow systems are outlined. (orig.)

Strategies to Engage Adolescents in Digital Health Interventions for Obesity Prevention and Management

Directory of Open Access Journals (Sweden)

Stephanie R. Partridge

2018-06-01

Full Text Available Obesity is one of the greatest health challenges facing today’s adolescents. Dietary interventions are the foundation of obesity prevention and management. As adolescents are digital frontrunners and early adopters of technology, digital health interventions appear the most practical modality for dietary behavior change interventions. Despite the rapid growth in digital health interventions, effective engagement with adolescents remains a pertinent issue. Key strategies for effective engagement include co-designing interventions with adolescents, personalization of interventions, and just-in-time adaptation using data from wearable devices. The aim of this paper is to appraise these strategies, which may be used to improve effective engagement and thereby improve the dietary behaviors of adolescents now and in the future.

Guidelines for Adolescent Preventive Services: the GAPS in practice.

Science.gov (United States)

Gadomski, Anne; Bennett, Shannon; Young, Margaret; Wissow, Lawrence S

2003-05-01

Pre- and post-Guidelines for Adolescent Preventive Services (GAPS) comparison of outcomes gathered via chart audit. A rural hospital-based general pediatric clinic. Adolescents who underwent annual examinations between April 1, 1998, and March 31, 2001. A random sample of 441 medical records was reviewed. Training in the GAPS model and use of the questionnaire began in April 1998. Detection of, discussion of, and referrals for GAPS-related risk behavior. The medical records of 162 younger adolescents (aged 11-15 years) and 279 older adolescents (aged 16-19 years) were audited. Detection of risk behaviors increased from 19% at baseline to 95% with the initial GAPS and 87% with the periodic GAPS. The most prevalent risk factor was having a rifle or gun in the home (younger adolescents, 47% and older adolescents, 39%). The mean number of risk behaviors and health concerns documented was higher in the initial GAPS (4.8 and 1.3, respectively) than in the periodic GAPS (3.8 and 0.7) (P =.01 and.006). The GAPS questionnaires detected lower levels of risk behavior compared with a local Youth Risk Behavior Survey. Controlling for sex, age, and clinician, discussion of psychosocial topics increased during the study period; however, there was considerable variation among clinicians regarding the topics addressed. The GAPS-related referral rate did not change significantly. The GAPS model increases clinicians' detection and discussion of risk behaviors.

It’s Called “Going Out to Play”: A Video Diary Study of Hmong Girls’ Perspectives on Running Away

Science.gov (United States)

Edinburgh, Laurel D.; Garcia, Carolyn M.; Saewyc, Elizabeth M.

2015-01-01

How do Hmong immigrant adolescent girls’ decide to run away, return home, leave again, or stay home? Video diaries by 11 sexually-exploited runaway Hmong girls, age 13–16, revealed four themes: “Fighting restrictions,” resisting family cultural expectations and desires to be like other American teens; “Not Running Away, Going Out to Play,” which captured impulsive decision-making; “Unrestrained Partying” described runaway experiences but minimized dangers they faced; and “Trying to Change,” returning home because of family bonds and wanting to “be someone good.” Given their limited ability to anticipate risks, interventions should focus on runaway prevention initiatives for Hmong families and teens. PMID:23311908

A Cognitive Behavioral Depression Prevention Program for Early Adolescents

Science.gov (United States)

Miloseva, Lence

2013-01-01

The aim of this study was to present results of our one year experience with Cognitive Behavioral Psychology Program, in order to contribute to the building of whole school approach and positive psychology preventive mental health problems model. Based on Penn Resilience program (PRP), we modify and create program for early adolescents: how to…

Runaway electron beam in atmospheric pressure discharges

International Nuclear Information System (INIS)

Oreshkin, E V; Barengolts, S A; Chaikovsky, S A; Oreshkin, V I

2015-01-01

A numerical simulation was performed to study the formation of a runaway electron (RAE) beam from an individual emission zone in atmospheric pressure air discharges with a highly overvolted interelectrode gap. It is shown that the formation of a RAE beam in discharges at high overvoltages is much contributed by avalanche processes. (paper)

Massive runaway stars in the Large Magellanic Cloud

Science.gov (United States)

Gvaramadze, V. V.; Kroupa, P.; Pflamm-Altenburg, J.

2010-09-01

The origin of massive field stars in the Large Magellanic Cloud (LMC) has long been an enigma. The recent measurements of large offsets (˜ 100 km s-1) between the heliocentric radial velocities of some very massive (O2-type) field stars and the systemic LMC velocity provides a possible explanation of this enigma and suggests that the field stars are runaway stars ejected from their birthplaces at the very beginning of their parent cluster's dynamical evolution. A straightforward way to prove this explanation is to measure the proper motions of the field stars and to show that they are moving away from one of the nearby star clusters or OB associations. This approach is, however, complicated by the long distance to the LMC, which makes accurate proper motion measurements difficult. We used an alternative approach for solving the problem (first applied for Galactic field stars), based on the search for bow shocks produced by runaway stars. The geometry of detected bow shocks would allow us to infer the direction of stellar motion, thereby determining their possible parent clusters. In this paper we present the results of a search for bow shocks around six massive field stars that have been proposed as candidate runaway stars. Using archival Spitzer Space Telescope data, we found a bow shock associated with one of our programme stars, the O2 V((f*)) star BI 237, which is the first-ever detection of bow shocks in the LMC. Orientation of the bow shock suggests that BI 237 was ejected from the OB association LH 82 (located at ≃ 120 pc in projection from the star). A by-product of our search is the detection of bow shocks generated by four OB stars in the field of the LMC and an arc-like structure attached to the candidate luminous blue variable R81 (HD 269128). The geometry of two of these bow shocks is consistent with the possibility that their associated stars were ejected from the 30 Doradus star-forming complex. We discuss implications of our findings for the

Sexual Abuse as a Precursor to Prostitution and Victimization among Adolescent and Adult Homeless Women.

Science.gov (United States)

Simons, Ronald L.; Whitbeck, Les B.

1991-01-01

Studied 40 adolescent runaways and 95 homeless women to examine impact of early sexual abuse on prostitution and victimization. Findings suggest that early sexual abuse increases probability of involvement in prostitution irrespective of influence of running away, substance abuse, and other deviant acts; only indirectly affects chances of…

Prevention of alcohol use in early adolescents: A joint venture of school and parents

NARCIS (Netherlands)

Koning, H.M.

2011-01-01

More than half of the Dutch adolescents start drinking before age 12 (Monshouwer et al., 2009). Early drinking is related to several developmental risks and to later alcohol and drug abuse (Behrendt et al., 2009). A Dutch alcohol prevention program (PAS) targets early adolescents and their parents

Comments on thermal runaway experiments in sub-ignition tokamaks

International Nuclear Information System (INIS)

Yamazaki, K.

1982-09-01

Justification of deuterium-tritium operations is discussed from the physics viewpoint and optimal thermal runaway experiments in high-field, high-density compact tokamaks are suggested within the minimization of the induced radioactivation. (author)

Preventing Filipino Mental Health Disparities: Perspectives from Adolescents, Caregivers, Providers, and Advocates.

Science.gov (United States)

Javier, Joyce R; Supan, Jocelyn; Lansang, Anjelica; Beyer, William; Kubicek, Katrina; Palinkas, Lawrence A

2014-12-01

Filipino Americans are the second largest immigrant population and second largest Asian ethnic group in the U.S. Disparities in youth behavioral health problems and the receipt of mental health services among Filipino youth have been documented previously. However, few studies have elicited perspectives from community stakeholders regarding how to prevent mental health disparities among Filipino youth. The purpose of the current study is to identify intervention strategies for implementing mental health prevention programs among Filipino youth. We conducted semi-structured interviews (n=33) with adolescents, caregivers, advocates, and providers and focus groups (n=18) with adolescents and caregivers. Interviews were audio taped and transcribed verbatim. Transcripts were analyzed using a methodology of "coding consensus, co-occurrence, and comparison" and was rooted in grounded theory. Four recommendations were identified when developing mental health prevention strategies among Filipino populations: address the intergenerational gap between Filipino parents and children, provide evidence-based parenting programs, collaborate with churches in order to overcome stigma associated with mental health, and address mental health needs of parents. Findings highlight the implementation of evidence-based preventive parenting programs in faith settings as a community-identified and culturally appropriate strategy to prevent Filipino youth behavioral health disparities.

Culturally Sensitive Risk Behavior Prevention Programs for African American Adolescents: A Systematic Analysis

Science.gov (United States)

Metzger, Isha; Cooper, Shauna M.; Zarrett, Nicole; Flory, Kate

2013-01-01

The current review conducted a systematic assessment of culturally sensitive risk prevention programs for African American adolescents. Prevention programs meeting the inclusion and exclusion criteria were evaluated across several domains: (1) theoretical orientation and foundation; (2) methodological rigor; (3) level of cultural integration; (4)…

Big-Data-Based Thermal Runaway Prognosis of Battery Systems for Electric Vehicles

Directory of Open Access Journals (Sweden)

Jichao Hong

2017-07-01

Full Text Available A thermal runaway prognosis scheme for battery systems in electric vehicles is proposed based on the big data platform and entropy method. It realizes the diagnosis and prognosis of thermal runaway simultaneously, which is caused by the temperature fault through monitoring battery temperature during vehicular operations. A vast quantity of real-time voltage monitoring data is derived from the National Service and Management Center for Electric Vehicles (NSMC-EV in Beijing. Furthermore, a thermal security management strategy for thermal runaway is presented under the Z-score approach. The abnormity coefficient is introduced to present real-time precautions of temperature abnormity. The results illustrated that the proposed method can accurately forecast both the time and location of the temperature fault within battery packs. The presented method is flexible in all disorder systems and possesses widespread application potential in not only electric vehicles, but also other areas with complex abnormal fluctuating environments.

Inflation expels runaways

Energy Technology Data Exchange (ETDEWEB)

Bachlechner, Thomas C. [Department of Physics, Columbia University,New York, NY 10027 (United States)

2016-12-30

We argue that moduli stabilization generically restricts the evolution following transitions between weakly coupled de Sitter vacua and can induce a strong selection bias towards inflationary cosmologies. The energy density of domain walls between vacua typically destabilizes Kähler moduli and triggers a runaway towards large volume. This decompactification phase can collapse the new de Sitter region unless a minimum amount of inflation occurs after the transition. A stable vacuum transition is guaranteed only if the inflationary expansion generates overlapping past light cones for all observable modes originating from the reheating surface, which leads to an approximately flat and isotropic universe. High scale inflation is vastly favored. Our results point towards a framework for studying parameter fine-tuning and inflationary initial conditions in flux compactifications.

45 CFR 1351.13 - What are the Federal and non-Federal match requirements under a Runaway and Homeless Youth grant?

Science.gov (United States)

2010-10-01

... requirements under a Runaway and Homeless Youth grant? 1351.13 Section 1351.13 Public Welfare Regulations... SERVICES THE ADMINISTRATION FOR CHILDREN, YOUTH AND FAMILIES, FAMILY AND YOUTH SERVICES BUREAU RUNAWAY AND HOMELESS YOUTH PROGRAM Runaway and Homeless Youth Program Grant § 1351.13 What are the Federal and non...

Receptivity of African American Adolescents to an HIV-Prevention Curriculum Enhanced by Text Messaging

Science.gov (United States)

Cornelius, Judith B.; St Lawrence, Janet S.

2013-01-01

PURPOSE This study assessed African American adolescents’ receptivity to an HIV-prevention curriculum enhanced by text messaging. DESIGN AND METHODS Two focus groups were conducted with 14 African American adolescents regarding how an HIV-prevention curriculum could be enhanced for text messaging delivery. RESULTS The adolescents were receptive to the idea of text messaging HIV-prevention information but wanted to receive a maximum of three messages per day during the hours of 4:00–6:00 p.m. PRACTICE IMPLICATIONS By taking the findings of this study, nurses, other healthcare providers, and community-based organizations can adapt evidence-based interventions for text messaging delivery to individuals at high risk for HIV infection. PMID:19356206

Multi-scale full-orbit analysis on phase-space behavior of runaway electrons in tokamak fields with synchrotron radiation

Energy Technology Data Exchange (ETDEWEB)

Wang, Yulei; Liu, Jian, E-mail: jliuphy@ustc.edu.cn [School of Nuclear Science and Technology and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Key Laboratory of Geospace Environment, CAS, Hefei, Anhui 230026 (China); Qin, Hong [School of Nuclear Science and Technology and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

2016-06-15

In this paper, the secular full-orbit simulations of runaway electrons with synchrotron radiation in tokamak fields are carried out using a relativistic volume-preserving algorithm. Detailed phase-space behaviors of runaway electrons are investigated in different dynamical timescales spanning 11 orders. In the small timescale, i.e., the characteristic timescale imposed by Lorentz force, the severely deformed helical trajectory of energetic runaway electron is witnessed. A qualitative analysis of the neoclassical scattering, a kind of collisionless pitch-angle scattering phenomena, is provided when considering the coupling between the rotation of momentum vector and the background magnetic field. In large timescale up to 1 s, it is found that the initial condition of runaway electrons in phase space globally influences the pitch-angle scattering, the momentum evolution, and the loss-gain ratio of runaway energy evidently. However, the initial value has little impact on the synchrotron energy limit. It is also discovered that the parameters of tokamak device, such as the toroidal magnetic field, the loop voltage, the safety factor profile, and the major radius, can modify the synchrotron energy limit and the strength of neoclassical scattering. The maximum runaway energy is also proved to be lower than the synchrotron limit when the magnetic field ripple is considered.

The role of the primary care provider in preventing and treating alcohol problems in adolescents

NARCIS (Netherlands)

Knight, [No Value

2001-01-01

Adolescents use alcohol more frequently and heavily than all other illicit drugs combined.(1) Given the myriad health, developmental, and social problems associated with alcohol use, it is not surprising that the American Medical Association's Guidelines for Adolescent Preventive Services recommends

Prevention of infection in children and adolescents with primary immunodeficiency disorders.

Science.gov (United States)

Papadopoulou-Alataki, Efimia; Hassan, Amel; Davies, E Graham

2012-12-01

Primary Immunodeficiency diseases (PIDs) are a heterogenous group of inherited disorders that may involve one or multiple components of the immune system. PIDs are uncommon, chronic and severe disorders, in which patients cannot mount a sufficiently protective immune response, leading to an increased susceptibility to infections. This review addresses the current practices for the prevention of infection in children and adolescents with PIDs, particular covering immunisations and antimicrobial prophylaxis. Over recent years, there have been major advances in molecular and cellular understanding in the field of PIDs. Many different disorders are recognised with variable spectra of infection susceptibility depending on the particular aspects of the immune response that are affected. Immunoglobulin prophylaxis is the mainstay of treatment for PIDs and provides passive protection. Prophylactic antimicrobials are efficacious in children and adolescents with predominant defects in primary T cell immunodeficiency diseases and phagocytic disorders, and also with predominant defects in antibody production. Prophylactic antibiotics are suggested for patients with antibody deficiency diseases if recurrent infections exceed three per year, if severe infections occur despite adequate immunoglobulin replacement and in hypogammaglobulinaemic patients who have bronchiectasis. Certain immunisations are effective in antibody deficiencies, T cell deficiencies, complement deficiencies and phagocytic disorders. There are remarkably few published data relating to clinical management aimed at preventing infectious complications in children and adolescents with PIDs. The cornerstones of the prevention of infection in most PID patients are: antimicrobial prophylaxis, appropriate vaccination, immunoglobulin replacement, for the more severe cases, and regular ongoing follow-up.

Obesity prevention in children and adolescents.

Science.gov (United States)

Swinburn, Boyd

2009-01-01

Childhood and adolescent obesity has been increasing in most middle- and high-income countries, and, as with adult obesity, this has been driven by increasingly obesogenic environments, especially the food environment. This constitutes a "market failure," signaling the need for government interventions with policies, programs, and social marketing. Population prevention strategies are critical, and children and adolescents should be the priority populations. Food marketing to children is a central policy issue for governments to address, and comprehensive regulations are needed to provide substantive protection for children. Community-based intervention programs show some real promise in reducing childhood obesity, but the 2 big challenges ahead are to ensure that there is substantial ongoing funding so that the community capacity to promote healthy weights can be scaled up to a national level and to ensure that policies are in place to support these efforts. The social and cultural shifts that support healthy eating and physical activity occur differentially, and special efforts are needed to reduce the socioeconomic gradients associated with childhood obesity. A positive public health approach encompassing environmental, regulatory, sociocultural, and educational strategies offer the best chance of reducing obesity without increasing disordered eating patterns.

Effective Prevention of Adolescent Substance Abuse--Educational versus Deterrent Approaches

Science.gov (United States)

Tze, Virginia M. C.; Li, Johnson C.-H.; Pei, Jacqueline

2012-01-01

Substance abuse, especially among adolescents, has long been an important issue in society. In light of the adverse impact of substance abuse, scholars, educators, and policy-makers have proposed different approaches to prevent and reduce such abuse. This paper investigates the effectiveness of the two prominent approaches--educational and…

Interventions for preventing unintended pregnancies among adolescents.

Science.gov (United States)

Oringanje, Chioma; Meremikwu, Martin M; Eko, Hokehe; Esu, Ekpereonne; Meremikwu, Anne; Ehiri, John E

2016-02-03

Unintended pregnancy among adolescents represents an important public health challenge in high-income countries, as well as middle- and low-income countries. Numerous prevention strategies such as health education, skills-building and improving accessibility to contraceptives have been employed by countries across the world, in an effort to address this problem. However, there is uncertainty regarding the effects of these interventions, hence the need to review the evidence-base. To assess the effects of primary prevention interventions (school-based, community/home-based, clinic-based, and faith-based) on unintended pregnancies among adolescents. We searched all relevant studies regardless of language or publication status up to November 2015. We searched the Cochrane Fertility Regulation Group Specialised trial register, The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2015 Issue 11), MEDLINE, EMBASE, LILACS, Social Science Citation Index and Science Citation Index, Dissertations Abstracts Online, The Gray Literature Network, HealthStar, PsycINFO, CINAHL and POPLINE and the reference lists of articles. We included both individual and cluster randomised controlled trials (RCTs) evaluating any interventions that aimed to increase knowledge and attitudes relating to risk of unintended pregnancies, promote delay in the initiation of sexual intercourse and encourage consistent use of birth control methods to reduce unintended pregnancies in adolescents aged 10 years to 19 years. Two authors independently assessed trial eligibility and risk of bias, and extracted data. Where appropriate, binary outcomes were pooled using a random-effects model with a 95% confidence interval (Cl). Where appropriate, we combined data in meta-analyses and assessed the quality of the evidence using the GRADE approach. We included 53 RCTs that enrolled 105,368 adolescents. Participants were ethnically diverse. Eighteen studies randomised individuals, 32

Developing and maintaining state-wide adolescent pregnancy prevention coalitions: a preliminary investigation.

Science.gov (United States)

Nezlek, J B; Galano, J

1993-09-01

This paper presents the results of a study of state-wide adolescent pregnancy prevention coalitions. Key informants in five states throughout the southern United States were given semi-structured interviews regarding the adolescent pregnancy prevention coalitions in their states. From these interviews and other documents, conclusions were drawn regarding the nature and importance of the environments within which these coalitions operate, the universe of activities in which coalitions engage, and the stages of development of these coalitions. Katz and Kahn's model of social organizations served as the basis for understanding coalitions in terms of these three considerations. Future research should consider the utility of organizational models that can explain more fully the organization--committee hybrid structure that tends to characterize these coalitions.

Using Amines and Alkanes as Thermal-Runaway Retardants for Lithium-Ion Battery

Science.gov (United States)

Shi, Yang

Thermal runaway imposes major challenges to large-scale lithium-ion batteries (LIBs). The working temperature of a LIB is usually around room temperature. However, upon mechanical abuse such as an impact or nail penetration, LIB cell components may fail and internal short circuits could be formed. As a result, a series of exothermic electrochemical reactions and decompositions would take place and the local temperature can rapidly increase. In this thesis, a few novel techniques are investigated to mitigate thermal runaway of LIBs. Mechanically triggered approach has been employed. Thermal-runaway retardant (TRR) is encapsulated in mechanically responsive packages made of materials inert to the battery environment, and upon external mechanical loadings the packages can be broken apart and release the TRR. This mechanism allows for the use of aggressive chemicals to suppress the short circuit discharge and reduce the subsequent exothermic phenomena, immediately after the battery is damaged even before temperature increase begins. The best TRR candidates are identified to be amines and alkanes. Among amines, secondary amines and tertiary amines perform better than primary amines. The reduction in electrolyte ionic conductivity and the displacement of electrolyte are the thermal-runaway-mitigation mechanisms of the secondary and the tertiary amines, respectively. Pentadecane is the best candidate among the alkanes under investigation, with the major working mechanism being electrolyte displacement. Impact tests on large pouch cells and high-energy battery chemistry were also performed; the results were quite encouraging.

On the origin of high-velocity runaway stars

Science.gov (United States)

Gvaramadze, Vasilii V.; Gualandris, Alessia; Portegies Zwart, Simon

2009-06-01

We explore the hypothesis that some high-velocity runaway stars attain their peculiar velocities in the course of exchange encounters between hard massive binaries and a very massive star (either an ordinary 50-100Msolar star or a more massive one, formed through runaway mergers of ordinary stars in the core of a young massive star cluster). In this process, one of the binary components becomes gravitationally bound to the very massive star, while the second one is ejected, sometimes with a high speed. We performed three-body scattering experiments and found that early B-type stars (the progenitors of the majority of neutron stars) can be ejected with velocities of >~200-400kms-1 (typical of pulsars), while 3-4Msolar stars can attain velocities of >~300-400kms-1 (typical of the bound population of halo late B-type stars). We also found that the ejected stars can occasionally attain velocities exceeding the Milky Ways's escape velocity.

[Prevention of overweight and obesity in children and adolescents in European countries].

Science.gov (United States)

Drewa, Aleksandra; Zorena, Katarzyna

2017-01-01

In the 21st century the occurrence of overweight and obesity in children and adolescents reaches the size of a global epidemic. It is recommended to promote a healthy lifestyle and, above all, to educate children, adolescents and adults about the dangerous consequences of being overweight or obese. It is crucial for prevention programs to comprise educational activities so that the participants are encouraged to change their lifestyle for better. However, it must be borne in mind that the overall effectiveness of such activities is determined by the commitment of both the obese child and the environment - the school or kindergarten and the media. Only integrated efforts can increase patients' awareness and reverse the growing trend in incidence of obesity around the world. This work discusses the current knowledge of overweight and obesity in children and adolescents, as well as the methods of prevention applied in various European countries. The analysis was based on up-to-date epidemiological data available in PubMed, Scopus, and Google Scholar databases. © Polish Society for Pediatric Endocrinology and Diabetology.

A Thermal Runaway Simulation on a Lithium Titanate Battery and the Battery Module

Directory of Open Access Journals (Sweden)

Man Chen

2015-01-01

Full Text Available Based on the electrochemical and thermal model, a coupled electro-thermal runaway model was developed and implemented using finite element methods. The thermal decomposition reactions when the battery temperature exceeds the material decomposition temperature were embedded into the model. The temperature variations of a lithium titanate battery during a series of charge-discharge cycles under different current rates were simulated. The results of temperature and heat generation rate demonstrate that the greater the current, the faster the battery temperature is rising. Furthermore, the thermal influence of the overheated cell on surrounding batteries in the module was simulated, and the variation of temperature and heat generation during thermal runaway was obtained. It was found that the overheated cell can induce thermal runaway in other adjacent cells within 3 mm distance in the battery module if the accumulated heat is not dissipated rapidly.

Teenage Pregnancy Prevention and Adolescents' Sexual Outcomes: An Experiential Approach

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Somers, Cheryl L.

2006-01-01

This study evaluates the effectiveness of an experiential approach to teen pregnancy (TP) prevention called "Baby Think It Over," a computerized infant simulator, on adolescents' attitudes and behaviors regarding teen pregnancy and sexuality. Recently, a more realistic model called "Real Care Baby" was developed. The small amount of research on…

THE NATURE OF THE HYPER-RUNAWAY CANDIDATE HIP 60350

International Nuclear Information System (INIS)

Irrgang, Andreas; Przybilla, Norbert; Heber, Ulrich; Fernanda Nieva, M.; Schuh, Sonja

2010-01-01

Young, massive stars in the Galactic halo are widely supposed to be the result of an ejection event from the Galactic disk forcing some stars to leave their place of birth as so-called runaway stars. Here, we present a detailed spectroscopic and kinematic analysis of the runaway B star HIP 60350 to determine which runaway scenario-a supernova explosion disrupting a binary system or dynamical interaction in star clusters-may be responsible for HIP 60350's peculiar orbit. Based on a non-local thermodynamic equilibrium approach, a high-resolution optical echelle spectrum was examined to revise spectroscopic quantities and for the first time to perform a differential chemical abundance analysis with respect to the B-type star 18 Peg. The results together with proper motions from the Hipparcos Catalog further allowed the three-dimensional kinematics of the star to be studied numerically. The abundances derived for HIP 60350 are consistent with a slightly supersolar metallicity agreeing with the kinematically predicted place of birth ∼6 kpc away from the Galactic center. However, they do not exclude the possibility of an α-enhanced abundance pattern expected in the case of the supernova scenario. Its outstanding high Galactic rest-frame velocity of 530 ± 35 km s -1 is a consequence of ejection in the direction of Galactic rotation and slightly exceeds the local Galactic escape velocity in a standard Galactic potential. Hence, HIP 60350 may be unbound to the Galaxy.

Adolescent HIV Prevention: An Application of the Elaboration Likelihood Model.

Science.gov (United States)

Metzler, April E.; Weiskotten, David; Morgen, Keith J.

Ninth grade students (n=298) participated in a study to examine the influence source credibility, message, quality, and personal relevance on HIV prevention message efficacy. A pilot study with adolescent focus groups created the high and low quality messages, as well as the high (HIV+) and low (worried parent) credibility sources. Participants…

Efficacy of technology-based interventions for obesity prevention in adolescents: a systematic review.

Science.gov (United States)

Chen, Jyu-Lin; Wilkosz, Mary Ellen

2014-01-01

About one third of adolescents in the USA are overweight and/or obese. Obesity during the adolescent years is associated with many adverse health consequences, including type 2 diabetes, hypertension, hyperlipidemia, and psychosocial problems. Because of substantial advances in technologies and wide acceptance by adolescents, it is now possible to use technology for healthy weight management and prevention of obesity. This systematic review used Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and aimed to evaluate the existing literature reported on the effectiveness of technology-based intervention (web-based, e-learning, and active video games) in preventing obesity in adolescents. The primary aim of this review was to explore if components of specific interventions were associated with a reduction in body mass index. Research articles obtained from CINAHL, Embase, PubMed, PsycInfo, and the Cochrane database from1990 to 2014 were reviewed. A total of 131 published articles were identified, and 14 met the inclusion criteria of a randomized or nonrandomized clinical study with body mass index as primary outcome and/or secondary outcomes of diet/physical activity and/or psychosocial function, tested lifestyle interventions to prevent obesity, used technology, and studied adolescents (aged 12-18 years). The results indicated that six of 14 studies found body mass index and/or body fat decreased at short-term (less than 12 months) follow-up. Six of eleven studies that examined physical activity or physical activity-related outcomes found an improved physical activity outcome (time playing active video games and increase in physical activity time), while five of seven studies which assessed dietary outcomes indicated improvement in dietary behaviors. Five of seven studies suggested an improvement in psychosocial function (reduced depression, improved self-esteem and efficacy, improvement on Behavior Assessment Scale) in adolescents

Randomized Trial of a Broad Preventive Intervention for Mexican American Adolescents

Science.gov (United States)

Gonzales, N.A.; Dumka, L.E.; Millsap, R.E.; Gottschall, A.; McClain, D.B.; Wong, J.J.; Germán, M.; Mauricio, A.M.; Wheeler, L.; Carpentier, F.D.; Kim, S.Y.

2012-01-01

Objective This randomized trial of a family-focused preventive intervention for Mexican American (MA) adolescents evaluated intervention effects on adolescent substance use, internalizing and externalizing symptoms, and school discipline and grade records in 8th grade, one year after completion of the intervention. The study also examined hypothesized mediators and moderators of intervention effects. Method Stratified by language of program delivery (English vs. Spanish), the trial included a sample of 516 MA adolescents (50.8% female; M =12.3 years, SD=.54) and at least one caregiver that were randomized to receive a low dosage control group workshop or the 9-week group intervention that included parenting, adolescent coping, and conjoint family sessions. Results Positive program effects were found on all five outcomes at one-year posttest, but varied depending on whether adolescents, parents, or teachers reported on the outcome. Intervention effects were mediated by posttest changes in effective parenting, adolescent coping efficacy, adolescent school engagement, and family cohesion. The majority of direct and mediated effects were moderated by language, with a larger number of significant effects for families that participated in Spanish. Intervention effects also were moderated by baseline levels of mediators and outcomes, with the majority showing stronger effects for families with poorer functioning at baseline. Conclusion Findings support the efficacy of the intervention to decrease multiple problem outcomes for MA adolescents, but also demonstrate differential effects for parents and adolescents receiving the intervention in Spanish vs. English, and depending on their baseline levels of functioning. PMID:22103956

Considerations for the definition, measurement, consequences, and prevention of dating violence victimization among adolescent girls.

Science.gov (United States)

Teten, Andra L; Ball, Barbara; Valle, Linda Anne; Noonan, Rita; Rosenbluth, Barri

2009-07-01

Violence experienced by adolescent girls from their dating partners poses considerable threat to their health and well-being. This report provides an overview of the prevalence and consequences of heterosexual teen dating violence and highlights the need for comprehensive prevention approaches to dating violence. We also discuss some considerations and future directions for the study and prevention of dating violence. We begin with a discussion of the definition of dating violence and also discuss measurement concerns and the need for evaluation of prevention strategies. Although women and men of all ages may be the victims or perpetrators, male-to-female dating violence experienced by adolescent girls is the main focus of this article. We incorporate research regarding girls' perpetration of dating violence where appropriate and as it relates to prevention.

Smoking uptake among Saudi adolescents: tobacco epidemic indicators and preventive actions needed.

Science.gov (United States)

Mohammed, Mutaz; Eggers, Sander Matthijs; Alotaiby, Fahad Falah; de Vries, Nanne; de Vries, Hein

2014-11-25

The aim of this cross-sectional school-based study was to assess smoking prevalence, indicators for the smoking epidemic and determinants of smoking among Saudi adolescents. The study included 695 male adolescents from 11 to 16 years of age who filled out self-report questionnaires based on the European Smoking Framework Approach questionnaire, which uses the I-Change model to assess attitude, social influence and the self-efficacy of the participants. Smokers were 275 (39.6%) adolescents. Smokers tended to receive more daily pocket money, live in more affluent families and show lower academic performance. Non-smokers were inclined to believe that smoking may help people to feel relaxed and confident, encountered less social influences to smoke than smokers, but reported low self-efficacy not to smoke when with smoker friends and when offered a cigarette. Smokers reported the lowest self-efficacy not to smoke in all situations assessed. The results suggest the smoking epidemic among male Saudi adolescents may still be in the early stages, providing ample opportunity for preventive actions aimed at halting the further progress of this epidemic. Secondly, smoking prevention programs in Saudi Arabia need to reinforce non-smoking attitudes, address how to resist pressure to smoke, and how to develop high self-efficacy towards non-smoking in various situations. © The Author(s) 2014.

[Knowledge and practices by adolescents in preventing occupational injuries: a qualitative study].

Science.gov (United States)

Nagai, Roberta; Lefèvre, Ana Maria C; Lefèvre, Fernando; Steluti, Josiane; Teixeira, Liliane R; Zinn, Lílian C S; Soares, Nilson S; Fischer, Frida M

2007-06-01

To describe knowledge and practices adopted by high school students to prevent occupational injuries. The study was carried out in a public school located in São Paulo, in 2003. Fifty-three evening students aged 14 to 21 years old participated the study, they were divided into two groups with and without job experience (32 and 21 students, respectively). The students answered two questions: "Why do occupational injuries occur?" and "How do you avoid occupational injuries?" Analyses were performed using the software "Quali-quanti" to structure collective discourses. ANALYSIS OF DISCOURSES: Adolescents with work experience reported that occupational injuries occur due to carelessness of the employee, bad luck of the employee, employer's negligence, lack of training, and unsafe workplace. Adolescents without work experience reported that the main causes of work injuries were carelessness of the employee and employer's negligence. Regarding the ways to protect themselves against occupational injuries, both groups reported that: they pay attention (would pay attention) and wear safety equipment (would wear) safety equipment. Adolescents from both groups showed limited knowledge about occupational injuries and prevention methods. Students "blamed the victim" to explain the injuries and considered "paying attention to work" as the best way to protect themselves. These facts showed that the culture of blaming the victim is present since adolescence and probably it is an outcome of a learning process of the society.

Prevention of adolescent reoccurring violence and alcohol abuse: a multiple site evaluation.

Science.gov (United States)

Wodarski, John S

2010-07-01

"Prevention of Adolescent Reoccurring Violence and Alcohol Abuse: A Multiple Site Evaluation" is a multiple component alcohol abuse and violent behavior prevention strategy, targeted to adolescents ages 16-21 who have high levels of anger, or who are victims/perpetrators of violence, and their families. Three community centers located in upstate New York provided group participants (N = 210) known to have conduct disorder and substance abuse history. The centers were used as the intervention sites over a seven-week period with the youth assessment staff using objective screening measures. The participants were exposed to a two-pronged intervention, using a parental involvement cohort with approximately half of the study participants. The Teams, Games, and Tournaments strategy was the intervention method. Teams, Games, and Tournaments is a Social Learning Theory-based intervention with demonstrated empirical evidence of the model's effectiveness. A 2 x 3 factorial design with two follow-up points encompassed: anger control, alcohol/substance abuse, and family interactive education. The goals of the study were to help adolescents reduce their alcohol use, to increase productive family interaction, and ultimately to reduce the adolescents' aggression levels and subsequently reduce the possibility of their becoming victims or perpetrators of a violent crime. Consistent with Social Learning Theory, the Teams, Games, and Tournaments treatment intervention makes use of adolescents as peer counselors. The practical implications include that professionals or students in our public schools, juvenile courts, correctional institutions, and residential treatment centers can easily implement this program. A standardized treatment manual is available. It offers a complete, ready-to-use, and cost-effective tool for reducing adolescent violence and alcohol abuse. Further, the data provide support for a hypothesis of social learning theory, that is: interventions using multiple

Incentives for preventing smoking in children and adolescents.

Science.gov (United States)

Hefler, Marita; Liberato, Selma C; Thomas, David P

2017-06-06

Adult smoking usually has its roots in adolescence. If individuals do not take up smoking during this period it is unlikely that they ever will. Further, once smoking becomes established, cessation is challenging; the probability of subsequently quitting is inversely proportional to the age of initiation. One novel approach to reducing the prevalence of youth smoking is the use of incentives. To assess the effect of incentives on preventing children and adolescents (aged 5 to 18 years) from starting to smoke. It was also our intention to assess, where possible, the dose-response of incentives, the costs of incentive programmes, whether incentives are more or less effective in combination with other interventions to prevent smoking initiation, and any unintended consequences arising from the use of incentives. For the original review (published 2012) we searched the Cochrane Tobacco Addiction Group Specialized Register, with additional searches of MEDLINE, Embase, CINAHL, CSA databases and PsycINFO for terms relating to incentives, in combination with terms for smoking and tobacco use, and children and adolescents. The most recent searches were of the Cochrane Tobacco Addiction Group Specialized Register, and were carried out in December 2016. We considered randomized controlled trials (RCTs) allocating children and adolescents (aged 5 to 18 years) as individuals, groups or communities to intervention or control conditions, where the intervention included an incentive aimed at preventing smoking uptake. We also considered controlled trials (CTs) with baseline measures and post-intervention outcomes. Two review authors extracted and independently assessed the data. The primary outcome was the smoking status of children or adolescents at follow-up who reported no smoking at baseline. We required a minimum follow-up of six months from baseline and assessed each included study for risks of bias. We used the most rigorous definition of abstinence in each trial; we did

A Pilot Study for Linking Adolescent Patients to an Interactive Tobacco Prevention Program

Directory of Open Access Journals (Sweden)

Karen S. Calabro

2017-04-01

Full Text Available Context: The American Academy of Pediatrics and professional guidelines recommend intervening with adolescents about avoiding tobacco use in the health-care setting. Barriers in the clinical setting limit consistent provision of this critical service. Objectives: This pilot study compared 2 approaches for referring adolescents to an evidence-based tobacco prevention and cessation program in the outpatient setting. Secondary aims assessed tobacco use, knowledge, and program evaluation. Design, Setting, and Participants: The study setting was a medical and dental clinic. Participants aged 13 to 18 received tobacco advice and instructions to work through “A Smoking Prevention Interactive Experience.” The program addresses health concerns of adolescents about tobacco use and is founded on behavioral change theories. The link to access it is featured on the website of the National Cancer Institute’s Research-Tested Interventions. Participants (N = 197 were randomized to 1 of 2 approaches (ie, a program link via e-mail or referral by a printed card. Results: The program was accessed by 57% (112 of 197 of participants. Both referral approaches were equally effective. Non-Hispanics were twice as likely to access the program as Hispanics (adjusted odds ratio = 2.1, 95% confidence interval = 1.2-3.8, P < .05. Over 95% of participants identified themselves as nonusers of tobacco and evaluated the program as beneficial in increasing knowledge and motivation to remain tobacco-free. Conclusion: Linking adolescent patients to an evidence-based tobacco prevention/cessation program at a community health clinic was highly promising and feasible. We present conclusions for future research.

Runaway reactions. Part 2 Causes of Accidents in selected CSB case histories Part 2

OpenAIRE

GYENES ZSUZSANNA; CARSON PHILLIP

2017-01-01

Part 1 briefly discussed the basic thermochemistry of reactive chemicals, the statistics of accidents involving runaway reactions, and general control measures to minimise risk and mitigate the consequences. The present paper highlights the main causes of major accidents from runaway reactions with illustrative case histories to link theory and practice. It also discusses lessons learned from these accidents, which are very similar in the cases studied. The main causes are management deficien...

Texting and Mobile Phone App Interventions for Improving Adherence to Preventive Behavior in Adolescents: A Systematic Review.

Science.gov (United States)

Badawy, Sherif M; Kuhns, Lisa M

2017-04-19

Many preventable behaviors contribute to adolescent mortality and morbidity. Non-adherence to preventive measures represents a challenge and has been associated with worse health outcomes in this population. The widespread use of electronic communication technologies by adolescents, particularly the use of text messaging (short message service, SMS) and mobile phones, presents new opportunities to intervene on risk and preventive risk behavior, but little is known about their efficacy. This study aimed to systematically evaluate evidence for the efficacy of text messaging and mobile phone app interventions to improve adherence to preventive behavior among adolescents and describe intervention approaches to inform intervention development. This review covers literature published between 1995 and 2015. Searches included PubMed, Embase, CENTRAL, PsycINFO, CINAHL, INSPEC, Web of Science, Google Scholar, and additional databases. The search strategy sought articles on text messaging and mobile phone apps combined with adherence or compliance, and adolescents and youth. An additional hand search of related themes in the Journal of Medical Internet Research was also conducted. Two reviewers independently screened titles and abstracts, assessed full-text articles, and extracted data from articles that met inclusion criteria. Included studies reflect original research-experimental or preexperimental designs with text messaging or mobile phone app interventions-targeting adherence to preventive behavior among adolescents (12-24 years old). The preferred reporting items of systematic reviews and meta-analyses (PRISMA) guidelines were followed for reporting results, and findings were critically appraised against the Oxford Centre for Evidence-based Medicine criteria. Of 1454 records, 19 met inclusion criteria, including text messaging (n=15) and mobile phone apps (n=4). Studies targeted clinic attendance, contraceptive use, oral health, physical activity and weight management

An Impact Triggered Runaway Greenhouse on Mars

Science.gov (United States)

Segura, T. L.; McKay, C. P.; Toon, O. B.

2004-01-01

When a planet is in radiative equilibrium, the incoming solar flux balances the outgoing longwave flux. If something were to perturb the system slightly, say the incoming solar flux increased, the planet would respond by radiating at a higher surface temperature. Since any radiation that comes in must go out, if the incoming is increased, the outgoing must also increase, and this increase manifests itself as a warmer equilibrium temperature. The increase in solar flux would correspond to an increase in temperature, which would increase the amount of water vapor in the atmosphere due to increased evaporation. Since water vapor is a greenhouse gas, it would absorb more radiation in the atmosphere leading to a yet warmer equilibrium temperature. The planet would reach radiative equilibrium at this new temperature. There exists a point, however, past which this positive feedback leads to a "runaway" situation. In this case, the planet does not simply evaporate a little more water and eventually come to a slightly higher equilibrium temperature. Instead, the planet keeps evaporating more and more water until all of the planet's available liquid and solid water is in the atmosphere. The reason for this is generally understood. If the planet's temperature increases, evaporation of water increases, and the absorption of radiation increases. This increases the temperature and the feedback continues until all water is in the atmosphere. The resulting equilibrium temperature is very high, much higher than the equilibrium temperature of a point with slightly lower solar flux. One can picture that as solar flux increases, planetary temperature also increases until the runaway point where temperature suddenly "jumps" to a higher value, in response to all the available water now residing in the atmosphere. This new equilibrium is called a "runaway greenhouse" and it has been theorized that this is what happened to the planet Venus, where the surface temperature is more than 700 K

Counseling About Skin Cancer Prevention Among Adolescents: What Do Parents Receive From Health Care Providers?

Science.gov (United States)

McRee, Annie-Laurie; Mays, Darren; Kornides, Melanie L; Gilkey, Melissa B

2017-10-01

Adolescence is a high-risk period for ultraviolet radiation exposure, a primary cause of skin cancer later in life. We sought to characterize receipt of health care provider-delivered counseling about skin cancer prevention (SCP) among parents of adolescents. In 2016, we conducted an online survey with a national sample of parents of adolescents aged 11-17 years (n = 1,253). Multivariable logistic regression assessed correlates of receiving counseling from a health care provider about any of the six skin cancer prevention (SCP) topics. Only half (49%) of parents recalled discussing any SCP topic with their child's provider; the prevalence was highest for sunscreen (39%) and lowest for indoor tanning (3%). Parents had greater odds of receiving counseling if they had a child with more sun-reactive skin (odds ratio [OR] = 1.53); a family history of skin cancer (OR = 1.38); or a higher quality relationship with the provider (OR = 1.47; all p attention to SCP counseling is needed, especially for exposures such as indoor tanning that remain prevalent among adolescents but are rarely addressed in clinical encounters. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Models of safe nutrition of children and adolescents as a basis for prevention of obesity.

Science.gov (United States)

Weker, Halina; Barańska, Marta

2011-01-01

The aim of the study was to present up-to-date nutrition models for children and adolescents in Poland on the basis of current research on obesity prevention. Up-to-date results of research on the link between nutritional factor and the nutritional status of children and adolescents, nutritional standards and recommendations of expert teams on healthy diet were analysed, based on the review of literature (Medline database) from the years 2005-2010. The main components of the model of safe nutrition for children and adolescents, which according to the current views should be combined with obesity prevention, include the frequency of meals, selection of products in a daily diet and observance of norms concerning energy and nutritional value of the diets. Other factors include family and environmental determinants, including dietary habits and behaviour, knowledge about nutrition and physical activity. The models of safe nutrition for children and adolescents in Poland are compliant with the current nutritional recommendations of the WHO and EU standards. The developed models of safe nutrition for children and adolescents must not only be popularised but also their efficiency needs to be increased by adjusting them to various groups of recipients.

Malaria: Knowledge and prevention practices among school adolescents in a coastal community in Calabar, Nigeria

Science.gov (United States)

Gyuse, Abraham N.; Etokidem, Aniekan J.

2010-01-01

ABSTRACT Background Malaria prevention and treatment constitute an unbearable economic burden to most African countries, especially south of the Sahara, where about 500 million cases occur annually. The problem of malaria among adolescents has largely been overshadowed by the huge burden of the disease among young children. Attention to malaria among adolescents has also been diverted by the huge burden of HIV/AIDS among adolescents. Some surveys reveal a lack of knowledge and many misconceptions about the transmission and treatment of malaria, which could adversely affect malaria control measures and antimalarial therapy. Such a knowledge gap could have an adverse effect on school children, who could be used as change agents and as role models for their siblings and peers in the malaria control strategy. Objectives To determine the malaria prevention practices of school adolescents in the coastal community of Calabar, Nigeria. Method This was a cross-sectional survey involving secondary schools in southern Calabar. Four hundred adolescents were randomly selected from the 4565 learners in 5 out of 17 secondary schools in southern Calabar, Cross River State, Nigeria. A self-administered, semi-structured questionnaire was administered to the respondents. Results Most respondents (77.5%) were aware that the vector transmits the malaria parasite through biting. Fewer respondents would prevent malaria attacks by clearing the vegetation in the peri-domestic environment (13.5%), filling up potholes (16.9%), opening up drainage (11%), using insecticide-treated nets (25.7%) or using antimalarial drugs (11.2%). Less than one-tenth (8%) would use various other methods such as not accepting unscreened blood, while only 11% obtained the information from their teachers. Conclusion The study identified knowledge gaps among school children. There is a need to empower teachers with information about the cause of malaria and prevention strategies.

Preventing Drug Abuse among Hispanic Adolescents: Developing a Responsive Intervention Approach

Science.gov (United States)

Schinke, Steven P.; Schwinn, Traci M.; Hursh, Hilary A.

2015-01-01

Intervention research is essential to help Hispanic American adolescents avoid drug use. This article describes an intervention research program aimed at preventing drug use among these youths. Grounded in salient epidemiological data, the program is informed by bicultural competence, social learning, and motivational interviewing theories. The…

The role of parents in preventing adolescent alcohol and cannabis use

NARCIS (Netherlands)

Vermeulen-Smit, Evelien

2014-01-01

This thesis aimed to investigate the role of parents in preventing adolescent alcohol and cannabis use. First, we investigated the association of specific parental drinking patterns with 12-15 year olds' drinking. Only two out of six parental drinking patterns, i.e. having a heavy drinking father

SOFT: a synthetic synchrotron diagnostic for runaway electrons

Science.gov (United States)

Hoppe, M.; Embréus, O.; Tinguely, R. A.; Granetz, R. S.; Stahl, A.; Fülöp, T.

2018-02-01

Improved understanding of the dynamics of runaway electrons can be obtained by measurement and interpretation of their synchrotron radiation emission. Models for synchrotron radiation emitted by relativistic electrons are well established, but the question of how various geometric effects—such as magnetic field inhomogeneity and camera placement—influence the synchrotron measurements and their interpretation remains open. In this paper we address this issue by simulating synchrotron images and spectra using the new synthetic synchrotron diagnostic tool SOFT (Synchrotron-detecting Orbit Following Toolkit). We identify the key parameters influencing the synchrotron radiation spot and present scans in those parameters. Using a runaway electron distribution function obtained by Fokker-Planck simulations for parameters from an Alcator C-Mod discharge, we demonstrate that the corresponding synchrotron image is well-reproduced by SOFT simulations, and we explain how it can be understood in terms of the parameter scans. Geometric effects are shown to significantly influence the synchrotron spectrum, and we show that inherent inconsistencies in a simple emission model (i.e. not modeling detection) can lead to incorrect interpretation of the images.

Family-Based Interventions in Preventing Children and Adolescents from Using Tobacco: A Systematic Review and Meta-Analysis.

Science.gov (United States)

Thomas, Roger E; Baker, Philip R A; Thomas, Bennett C

2016-07-01

Tobacco is the main preventable cause of death and disease worldwide. Adolescent smoking is increasing in many countries with poorer countries following the earlier experiences of affluent countries. Preventing adolescents from starting smoking is crucial to decreasing tobacco-related illness. To assess effectiveness of family-based interventions alone and combined with school-based interventions to prevent children and adolescents from initiating tobacco use. Fourteen bibliographic databases and the Internet, journals hand-searched, and experts consulted. Randomized controlled trials (RCTs) with children or adolescents and families, interventions to prevent starting tobacco use, and follow-up ≥6 months. Abstracts/titles independently assessed and data independently entered by 2 authors. Risk of bias was assessed with the Cochrane Risk-of-Bias tool. Twenty-seven RCTs were included. Nine trials of never-smokers compared with a control provided data for meta-analysis. Family intervention trials had significantly fewer students who started smoking. Meta-analysis of 2 RCTs of combined family and school interventions compared with school only, showed additional significant benefit. The common feature of effective high-intensity interventions was encouraging authoritative parenting. Only 14 RCTs provided data for meta-analysis (approximately a third of participants). Of the 13 RCTs that did not provide data for meta-analysis 8 compared a family intervention with no intervention and 1 reported significant effects, and 5 compared a family combined with school intervention with a school intervention only and none reported additional significant effects. There is moderate-quality evidence that family-based interventions prevent children and adolescents from starting to smoke. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Runaway pacemaker: a forgotten phenomenon?

Science.gov (United States)

Ortega, Daniel F; Sammartino, M Victoria; Pellegrino, Graciela M M; Barja, Luis D; Albina, Gaston; Segura, Eliseo V; Balado, Roberto; Laiño, Ruben; Giniger, Alberto G

2005-11-01

Runaway is an uncommon pacemaker dysfunction, characterized by fast and erratic spikes at non-physiological rates. This infrequent but potentially lethal failure mode may be related to low battery voltage. Four single chamber pacemaker patients were analyzed (Medtronic Minix ST 8330, Minneapolis, MN, had been implanted in two patients and two CPI Triumph VR 1124, St Paul, MN, in the other two). They had been admitted because of presyncopal episodes. Typical high rate stimuli at 2000 ppm alternating with pacing at 60-65 ppm were recorded in all ECGs. Lead system tests were normal. The pulse generators had to be replaced.

Disk tides and accretion runaway

Science.gov (United States)

Ward, William R.; Hahn, Joseph M.

1995-01-01

It is suggested that tidal interaction of an accreting planetary embryo with the gaseous preplanetary disk may provide a mechanism to breach the so-called runaway limit during the formation of the giant planet cores. The disk tidal torque converts a would-be shepherding object into a 'predator,' which can continue to cannibalize the planetesimal disk. This is more likely to occur in the giant planet region than in the terrestrial zone, providing a natural cause for Jupiter to predate the inner planets and form within the O(10(exp 7) yr) lifetime of the nebula.

Runaway dilaton and equivalence principle violations

CERN Document Server

Damour, Thibault Marie Alban Guillaume; Veneziano, Gabriele; Damour, Thibault; Piazza, Federico; Veneziano, Gabriele

2002-01-01

In a recently proposed scenario, where the dilaton decouples while cosmologically attracted towards infinite bare string coupling, its residual interactions can be related to the amplitude of density fluctuations generated during inflation, and are large enough to be detectable through a modest improvement on present tests of free-fall universality. Provided it has significant couplings to either dark matter or dark energy, a runaway dilaton can also induce time-variations of the natural "constants" within the reach of near-future experiments.

Peer mentorship program on HIV/AIDS knowledge, beliefs, and prevention attitudes among orphaned adolescents: an evidence based practice

Science.gov (United States)

Nabunya, Proscovia; Ssewamala, Fred M.; Mukasa, Miriam N.; Byansi, William; Nattabi, Jennifer

2015-01-01

Adolescents and young adults in sub-Saharan Africa (SSA) are particularly vulnerable to human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) infection. Adolescents orphaned as a direct result of HIV/AIDS are at an elevated risk of acquiring HIV/AIDS and other sexually transmitted infections. However, limited empirical evidence exists on HIV knowledge and prevention programs, especially those designed to address HIV information gaps among adolescents. This study evaluates the effect of a peer mentorship program provided in addition to other supportive services on HIV/AIDS knowledge, beliefs, and prevention attitudes, among school-going orphaned adolescents in southern Uganda. We utilize data from the Bridges to the Future Study, a 5-year longitudinal randomized experimental study funded by the National Institute of Child Health and Human Development. Out of the 1410 adolescents enrolled in the study (average age = 12.7 at study initiation), 855 of them participated in a nine-session, curriculum based peer mentorship program. We analyzed data collected at baseline and 12-months post intervention initiation. The results from bivariate and regression analysis indicate that, controlling for socioeconomic characteristics, adolescents who participated in a peer mentorship program were more likely than non-participants to report increased scores on HIV/AIDS knowledge(b = .86, 95%CI = .47 – 1.3, p ≤ .001); better scores on desired HIV/AIDS-related beliefs (b = .29, 95%CI = .06 – .52, p ≤ .01); and better scores on HIV/AIDS prevention attitudes (b = .76, 95%CI = .16 – 1.4, p ≤ .01). Overall, the study findings point to the potential role a of peer mentorship program in promoting the much-desired HIV/AIDS knowledge, beliefs, and prevention attitudes among orphaned adolescents. Future programs and policies that support AIDS-orphaned adolescents in sub-Saharan Africa should consider incorporating peer mentoring programs that provide

A randomized trial of the effect of centralized reminder/recall on immunizations and preventive care visits for adolescents.

Science.gov (United States)

Szilagyi, Peter G; Albertin, Christina; Humiston, Sharon G; Rand, Cynthia M; Schaffer, Stanley; Brill, Howard; Stankaitis, Joseph; Yoo, Byung-Kwang; Blumkin, Aaron; Stokley, Shannon

2013-01-01

To assess the impact of a managed care-based patient reminder/recall system on immunization rates and preventive care visits among low-income adolescents. We conducted a randomized controlled trial between December 2009 and December 2010 that assigned adolescents aged 11-17 years to one of three groups: mailed letter, telephone reminders, or control. Publicly insured youths (n = 4115) were identified in 37 participating primary care practices. The main outcome measures were immunization rates for routine vaccines (meningococcus, pertussis, HPV) and preventive visit rates at study end. Intervention and control groups were similar at baseline for demographics, immunization rates, and preventive visits. Among adolescents who were behind at the start, immunization rates at study end increased by 21% for mailed (P immunizations and preventive visits, with modest costs and modest impact. Copyright © 2013 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

Reclaiming Gender and Power in Sexual Violence Prevention in Adolescence.

Science.gov (United States)

Miller, Elizabeth

2018-03-01

The Mentors in Violence Prevention (MVP) model seeks to address the root causes of gender violence using a bystander approach and leadership training to challenge structures of patriarchy. Emerging research on adolescent relationship abuse and sexual violence points to key modifiable targets-transforming gender norms, addressing homophobia, integrating with comprehensive sexuality education, and acknowledging the needs of youth already exposed to violence. A social justice-based bystander approach such as the MVP model should be part of a multi-level approach to sexual violence prevention that addresses gender and power, encourages healthy sexuality conversations, and provides safety and support for survivors.

Counseling Received by Adolescents Undergoing Voluntary Medical Male Circumcision: Moving Toward Age-Equitable Comprehensive Human Immunodeficiency Virus Prevention Measures.

Science.gov (United States)

Kaufman, Michelle R; Patel, Eshan U; Dam, Kim H; Packman, Zoe R; Van Lith, Lynn M; Hatzold, Karin; Marcell, Arik V; Mavhu, Webster; Kahabuka, Catherine; Mahlasela, Lusanda; Njeuhmeli, Emmanuel; Seifert Ahanda, Kim; Ncube, Getrude; Lija, Gissenge; Bonnecwe, Collen; Tobian, Aaron A R

2018-04-03

The minimum package of voluntary medical male circumcision (VMMC) services, as defined by the World Health Organization, includes human immunodeficiency virus (HIV) testing, HIV prevention counseling, screening/treatment for sexually transmitted infections, condom promotion, and the VMMC procedure. The current study aimed to assess whether adolescents received these key elements. Quantitative surveys were conducted among male adolescents aged 10-19 years (n = 1293) seeking VMMC in South Africa, Tanzania, and Zimbabwe. We used a summative index score of 8 self-reported binary items to measure receipt of important elements of the World Health Organization-recommended HIV minimum package and the US President's Emergency Plan for AIDS Relief VMMC recommendations. Counseling sessions were observed for a subset of adolescents (n = 44). To evaluate factors associated with counseling content, we used Poisson regression models with generalized estimating equations and robust variance estimation. Although counseling included VMMC benefits, little attention was paid to risks, including how to identify complications, what to do if they arise, and why avoiding sex and masturbation could prevent complications. Overall, older adolescents (aged 15-19 years) reported receiving more items in the recommended minimum package than younger adolescents (aged 10-14 years; adjusted β, 0.17; 95% confidence interval [CI], .12-.21; P benefits or uptake of HIV testing. These self-reported findings were confirmed during counseling observations. Moving toward age-equitable HIV prevention services during adolescent VMMC likely requires standardizing counseling content, as there are significant age differences in HIV prevention content received by adolescents.

Velocity Distributions of Runaway Stars Produced by Supernovae in ...

Indian Academy of Sciences (India)

J. Astrophys. Astr. (2016) 37: 22. DOI: 10.1007/s12036-016-9400-2. Velocity Distributions of Runaway Stars Produced by Supernovae in the Galaxy. Abudusaimaitijiang Yisikandeer. ∗. , Chunhua Zhu, Zhaojun Wang. & Guoliang Lü. School of Physical Science and Technology, Xinjiang University, Urumqi, 830046, China. ∗.

Conceptual design of the Radial Gamma Ray Spectrometers system for α particle and runaway electron measurements at ITER

DEFF Research Database (Denmark)

Nocente, Massimo; Tardocchi, Marco; Barnsley, Robin

2017-01-01

We here present the principles and main physics capabilities behind the design of the radial gamma ray spectrometers (RGRS) system for alpha particle and runaway electron measurements at ITER. The diagnostic benefits from recent advances in gamma-ray spectrometry for tokamak plasmas and combines...... the measurements sensitive to α particles at characteristic resonant energies and to possible anisotropies of their slowing down distribution function. An independent assessment of the neutron rate by gamma-ray emission is also feasible. In case of runaway electrons born in disruptions with a typical duration...... of 100ms, a time resolution of at least 10ms for runaway electron studies can be achieved depending on the scenario and down to a current of 40 kA by use of external gas injection. We find that the bremsstrahlung spectrum in the MeV range from confined runaways is sensitive to the electron velocity space...

Resolving runaway electron distributions in space, time, and energy

Science.gov (United States)

Paz-Soldan, C.; Cooper, C. M.; Aleynikov, P.; Eidietis, N. W.; Lvovskiy, A.; Pace, D. C.; Brennan, D. P.; Hollmann, E. M.; Liu, C.; Moyer, R. A.; Shiraki, D.

2018-05-01

Areas of agreement and disagreement with present-day models of runaway electron (RE) evolution are revealed by measuring MeV-level bremsstrahlung radiation from runaway electrons (REs) with a pinhole camera. Spatially resolved measurements localize the RE beam, reveal energy-dependent RE transport, and can be used to perform full two-dimensional (energy and pitch-angle) inversions of the RE phase-space distribution. Energy-resolved measurements find qualitative agreement with modeling on the role of collisional and synchrotron damping in modifying the RE distribution shape. Measurements are consistent with predictions of phase-space attractors that accumulate REs, with non-monotonic features observed in the distribution. Temporally resolved measurements find qualitative agreement with modeling on the impact of collisional and synchrotron damping in varying the RE growth and decay rate. Anomalous RE loss is observed and found to be largest at low energy. Possible roles for kinetic instability or spatial transport to resolve these anomalies are discussed.

Efficacy of technology-based interventions for obesity prevention in adolescents: a systematic review

Directory of Open Access Journals (Sweden)

Chen JL

2014-08-01

Full Text Available Jyu-Lin Chen,1 Mary Ellen Wilkosz2 1Department of Family Health Care Nursing, School of Nursing, University of California, San Francisco, CA, 2Nursing Department, Sonoma State University, Rohnert Park, CA, USA Abstract: About one third of adolescents in the USA are overweight and/or obese. Obesity during the adolescent years is associated with many adverse health consequences, including type 2 diabetes, hypertension, hyperlipidemia, and psychosocial problems. Because of substantial advances in technologies and wide acceptance by adolescents, it is now possible to use technology for healthy weight management and prevention of obesity. This systematic review used Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and aimed to evaluate the existing literature reported on the effectiveness of technology-based intervention (web-based, e-learning, and active video games in preventing obesity in adolescents. The primary aim of this review was to explore if components of specific interventions were associated with a reduction in body mass index. Research articles obtained from CINAHL, Embase, PubMed, PsycInfo, and the Cochrane database from1990 to 2014 were reviewed. A total of 131 published articles were identified, and 14 met the inclusion criteria of a randomized or nonrandomized clinical study with body mass index as primary outcome and/or secondary outcomes of diet/physical activity and/or psychosocial function, tested lifestyle interventions to prevent obesity, used technology, and studied adolescents (aged 12–18 years. The results indicated that six of 14 studies found body mass index and/or body fat decreased at short-term (less than 12 months follow-up. Six of eleven studies that examined physical activity or physical activity-related outcomes found an improved physical activity outcome (time playing active video games and increase in physical activity time, while five of seven studies which assessed dietary

High performance gamma-ray spectrometer for runaway electron studies on the FT-2 tokamak

Energy Technology Data Exchange (ETDEWEB)

Shevelev, A.E., E-mail: Shevelev@cycla.ioffe.ru [Ioffe Institute, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Khilkevitch, E.M.; Lashkul, S.I.; Rozhdestvensky, V.V.; Altukhov, A.B.; Chugunov, I.N.; Doinikov, D.N.; Esipov, L.A.; Gin, D.B.; Iliasova, M.V.; Naidenov, V.O.; Nersesyan, N.S.; Polunovsky, I.A.; Sidorov, A.V. [Ioffe Institute, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Kiptily, V.G. [CCFE, Culham Science Centre, Abingdon, Oxon X14 3DB (United Kingdom)

2016-09-11

A gamma-ray spectrometer based on LaBr{sub 3}(Ce) scintillator has been used for measurements of hard X-ray emission generated by runaway electrons in the FT-2 tokamak plasmas. Using of the fast LaBr{sub 3}(Ce) has allowed extending count rate range of the spectrometer by a factor of 10. A developed digital processing algorithm of the detector signal recorded with a digitizer sampling rate of 250 MHz has provided a pulse height analysis at count rates up to 10{sup 7} s{sup −1}. A spectrum deconvolution code DeGaSum has been applied for inferring the energy distribution of runaway electrons escaping from the plasma and interacting with materials of the FT-2 limiter in the vacuum chamber. The developed digital signal processing technique for LaBr{sub 3}(Ce) spectrometer has allowed studying the evolution of runaways energy distribution in the FT-2 plasma discharges with time resolution of 1–5 ms.

Assessment of lnternational Space Station (ISS) Lithium-ion Battery Thermal Runaway (TR)

Science.gov (United States)

Graika, Jason

2017-01-01

This task was developed in the wake of the Boeing 787 Dreamliner lithium-ion battery TR incidents of January 2013 and January 2014. The Electrical Power Technical Discipline Team supported the Dreamliner investigations and has followed up by applying lessons learned to conduct an introspective evaluation of NASA's risk of similar incidents in its own lithium-ion battery deployments. This activity has demonstrated that historically NASA, like Boeing and others in the aerospace industry, has emphasized the prevention of TR in a single cell within the battery (e.g., cell screening) but has not considered TR severity-reducing measures in the event of a single-cell TR event. center dotIn the recent update of the battery safety standard (JSC 20793) to address this paradigm shift, the NASA community included requirements for assessing TR severity and identifying simple, low-cost severity reduction measures. This task will serve as a pathfinder for meeting those requirements and will specifically look at a number of different lithium-ion batteries currently in the design pipeline within the ISS Program batteries that, should they fail in a Dreamliner-like incident, could result in catastrophic consequences. This test is an abuse test to understand the heat transfer properties of the cell and ORU in thermal runaway, with radiant barriers in place in a flight like test in on orbit conditions. This includes studying the heat flow and distribution in the ORU. This data will be used to validate the thermal runaway analysis. This test does not cover the ambient pressure case. center dotThere is no pass/ fail criteria for this test.

Smoking among adolescents in Northern Greece: a large cross-sectional study about risk and preventive factors

Directory of Open Access Journals (Sweden)

Spyratos Dionisios G

2012-09-01

Full Text Available Abstract Background The aim of the present study was to investigate epidemiological data about cigarette smoking in relation with risk and preventive factors among Greek adolescents. Methods We randomly selected 10% of the whole number of schools in Northern Greece (133 schools, 18,904 participants were included. Two anonymous questionnaires (smoker's and non-smoker's were both distributed to all students so they selected and filled in only one. A parental signed informed consent was obtained using an informative leaflet about adolescent smoking. Results The main findings of the study were: a 14.2% of the adolescents (mean age+/−SD: 15.3+/−1.7 years reported regular smoking (24.1% in the age group 16–18 years, b 84.2% of the current smokers reported daily use, c students who live in urban and semirural areas smoke more frequently than those in rural areas, d students in technically oriented schools smoke twice as frequent compared to those in general education, e risk factors for smoking: male gender, low educational level of parents, friends who smoke (OR: 10.01, 95%CI: 8.53-11.74, p Conclusions Even though prevalence of cigarette smoking is not too high among Greek adolescents, frequency of everyday cigarette use is alarming. We identified many social and lifestyle risk and preventive factors that should be incorporated in a national smoking prevention program among Greek adolescents.

A Family Focused Randomized Controlled Trial to Prevent Adolescent Alcohol and Tobacco Use: The Moderating Roles of Positive Parenting and Adolescent Gender

Science.gov (United States)

Jones, Deborah J.; Olson, Ardis L.; Forehand, Rex; Gaffney, Cecelia A.; Zens, Michael S.; Bau, J. J.

2005-01-01

Four years of longitudinal data from 2,153 families with a 5th- or 6th-grade preadolescent participating in a family-focused pediatric primary-care-based prevention program were used to examine whether prevention effects were moderated by positive parenting and/or adolescent gender. Alcohol and tobacco use, internalizing problems, and…

"Mbizi": Empowerment and HIV/AIDS Prevention for Adolescent Girls in Botswana

Science.gov (United States)

Nitza, Amy; Chilisa, Bagele; Makwinja-Morara, Veronica

2010-01-01

This article describes a small group intervention for HIV/AIDS prevention among adolescent girls in Botswana. The psychoeducational group model is designed to empower girls to overcome the gender inequality that puts women at increased risk of HIV infection in the country. Group goals include heightening group members' awareness of the influence…

Exploring the context of trafficking and adolescent sex industry involvement in Tijuana, Mexico: consequences for HIV risk and prevention.

Science.gov (United States)

Goldenberg, Shira M; Silverman, Jay G; Engstrom, David; Bojorquez-Chapela, Ietza; Usita, Paula; Rolón, María Luisa; Strathdee, Steffanie A

2015-04-01

Coerced and adolescent sex industry involvement are linked to serious health and social consequences, including enhanced risk of HIV infection. Using ethnographic fieldwork, including interviews with 30 female sex workers with a history of coerced or adolescent sex industry involvement, we describe contextual factors influencing vulnerability to coerced and adolescent sex industry entry and their impacts on HIV risk and prevention. Early gender-based violence and economic vulnerability perpetuated vulnerability to coercion and adolescent sex exchange, while HIV risk mitigation capacities improved with increased age, control over working conditions, and experience. Structural interventions addressing gender-based violence, economic factors, and HIV prevention among all females who exchange sex are needed. © The Author(s) 2015.

Observation of a periodic runaway in the reactive Ar/O2 high power impulse magnetron sputtering discharge

Directory of Open Access Journals (Sweden)

Seyedmohammad Shayestehaminzadeh

2015-11-01

Full Text Available This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O2 discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

Investigation of runaway electrons in the PRETEXT Tokamak

International Nuclear Information System (INIS)

Eckstrand, S.A.

1981-01-01

High energy (0.2 to 0.4 MeV) runaway electrons have been studied in PRETEXT discharges by detecting the hard x-ray bremsstrahlung radiation produced when they escape from the discharge and strike the limiter. A pulse height analysis system, which included pileup rejection circuitry because of the high count rate, recorded both the amplitude and arrival time of each pulse

Studies of Plasma Instabilities Excited by Ground-Based High Power HF (Heating) Facilities and of X and Gamma Ray Emission in Runaway Breakdown Processes

National Research Council Canada - National Science Library

Gurevich, Aleksander V

2006-01-01

.... The runaway breakdown process in inhomogeneous thunderstorm electric field; 5. X-ray emission in different gases due to runaway breakdown phenomena in a laboratory cyclotron installation; 6. An influence of combined effects of runaway breakdown and cosmic rays on lightning processes in thunderstorm atmosphere.

Prevention of adolescent depression in the Spanish-speaking world

OpenAIRE

Horn, Andrea B; Canizares, Catalina; Gomez, Yvonne

2014-01-01

This paper aims at presenting programs targeted at the prevention of adolescent depression applied with Spanish-speaking populations that have been developed in Spanish-speaking countries and are mostly published in Spanish. These programs have been developed under different cultural contexts in Spain and Latin-America. The main goal of this paper is to make the studies and movements of the Spanish-speaking literature in this field accessible to the non-Spanish-speaking part of the research c...

[Prevalence of helmet use in children and adolescents in Germany and preventable bicycle-related head injuries].

Science.gov (United States)

Gutsche, J; Hintzpeter, B; Neuhauser, H; Schlaud, M

2011-08-01

Head injuries are the main cause of death in bicycle-related accidents among children and adolescents. According to a Cochrane Review, the risk of head injury (OR 0.31; 95% CI 0.26-0.37) or brain injury (OR 0.31; 95% CI 0.23-0.42) decreases by 69% if a helmet is worn. This study presents the prevalence of helmet use in cycling children and adolescents in Germany and the proportion of head injuries that could be prevented by wearing helmets. The potential effects of increased helmet wearing rates on the population attributable risk percentage for head injuries (PAR%) are demonstrated. The prevalence of helmet use in children aged 3-17 years was analysed using data from the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). The percentage of head injuries preventable by helmet use in this group is estimated by calculating PAR%. Prevalence rates of helmet use and odds ratios from a Cochrane Review about the effectiveness of bicycle helmets for the prevention of head injuries were used for analysis. The potential effect of increased helmet use is shown in 3 scenarios by means of differences of PAR% values in the most relevant age groups. The older the children, the less likely they are to wear a helmet: 89.5% (95% CI 88.0%-90.8%) of the 3- to 6-year-old children wear a helmet when cycling but only 11.0% (95% CI 9.3%-12.9%) of 14- to 17-year-old adolescents do. In the youngest group (3-6 years) 19% of bicycle-related head injuries are attributable to the non-use of helmets, but this proportion rises to 67% in the oldest group (14-17 years). The PAR% of head injuries associated with not wearing a helmet may be reduced by more than a third by increasing the helmet wearing rate to 67% (2 out of 3) among adolescents, and may be reduced to half if 75% of adolescents wore a helmet. Particularly older children and adolescents hardly use bicycle helmets, hence the rate of preventable head injury is high. Efforts towards increasing helmet use

Structural drivers and social protection: mechanisms of HIV risk and HIV prevention for South African adolescents.

Science.gov (United States)

Cluver, Lucie Dale; Orkin, Frederick Mark; Meinck, Franziska; Boyes, Mark Edward; Sherr, Lorraine

2016-01-01

Social protection is high on the HIV-prevention agenda for youth in sub-Saharan Africa. However, questions remain: How do unconditional cash transfers work? What is the effect of augmenting cash provision with social care? And can "cash plus care" social protection reduce risks for adolescents most vulnerable to infection? This study tackles these questions by first identifying mediated pathways to adolescent HIV risks and then examining potential main and moderating effects of social protection in South Africa. This study was a prospective observational study of 3515 10-to-17-year-olds (56.7% female; 96.8% one-year retention). Within randomly selected census areas in four rural and urban districts in two South African provinces, all homes with a resident adolescent were sampled between 2009/2010 and 2011/2012. Measures included 1) potential structural drivers of HIV infection such as poverty and community violence; 2) HIV risk behaviours; 3) hypothesized psychosocial mediating factors; and 4) types of social protection involving cash and care. Using gender-disaggregated analyses, longitudinal mediation models were tested for potential main and moderating effects of social protection. Structural drivers were associated with increased onset of adolescent HIV risk behaviour (psocial protection were associated with reductions in HIV risk behaviour and psychosocial deprivations. In addition, cash social protection moderated risk pathways: for adolescent girls and boys experiencing more acute structural deprivation, social protection had the greatest associations with HIV risk prevention (e.g. moderation effects for girls: B=-0.08, psocial protection has the greatest prevention effects for the most vulnerable. Social protection comprising unconditional cash plus care was associated with reduced risk pathways through moderation and main effects, respectively. Our findings suggest the importance of social protection within a combination package of HIV-prevention

Comparison of thermal runaway limits under different test conditions based on a 4.5 kV IGBT

DEFF Research Database (Denmark)

Reigosa, Paula Diaz; Prindle, D.; Pâques, Gontran

2016-01-01

runaway takes place. In this paper guidelines are proposed based on the correlation among short circuit withstand capability and off-state leakage current for guarantying reliable operation and ensuring that they are thermally stable under parameter variations. This study is helpful to facilitate...... application engineers for defining the correct stability criteria and/or margins in respect of thermal runaway....

Strategies for the prevention of MP3-induced hearing loss among adolescents: expert opinions from a Delphi study.

Science.gov (United States)

Vogel, Ineke; Brug, Johannes; van der Ploeg, Catharina P B; Raat, Hein

2009-05-01

To identify parties involved in the prevention of MP3-induced hearing loss among adolescents and potentially effective prevention strategies and interventions. Thirty experts in fields such as scientific research, medical practice, community health professions, education, youth work, music entertainment, and enforcement authorities participated in a qualitative, electronic, 3-round, Web-based Delphi study. Multiple parties involved in the prevention of MP3-induced hearing loss among adolescents were identified; the most relevant are the adolescents themselves, their parents, manufacturers of MP3 players and earphones, and the authorities. The experts did not expect that adolescents in general would perform the necessary protective behaviors to prevent MP3-induced hearing loss. Two environmental health protection measures were identified as both relevant and feasible to be implemented (ie, authorities encourage manufacturers to produce safer products, and public health campaigns will be held to improve knowledge of the risks of high-volume music, possible protective measures, and consequences of hearing loss). Authorities, the music industry in general, and especially manufacturers of MP3 players and earphones should recognize their responsibility and create a safer MP3-listening environment by taking measures to protect today's youth from the dangers of listening to high-volume music on MP3 players.

The effects of moms and teens for safe dates: a dating abuse prevention program for adolescents exposed to domestic violence.

Science.gov (United States)

Foshee, Vangie A; Benefield, Thad; Dixon, Kimberly S; Chang, Ling-Yin; Senkomago, Virginia; Ennett, Susan T; Moracco, Kathryn E; Michael Bowling, J

2015-05-01

Adolescents exposed to domestic violence are at high risk for dating abuse. This randomized controlled trial evaluated a dating abuse prevention program designed specifically for this risk group. Moms and Teens for Safe Dates consisted of six mailed booklets of dating abuse prevention information and interactive activities. Mothers who had been victims of domestic violence but no longer lived with the abuser delivered the program to their adolescents who had been exposed to the abuse. Mother and adolescent pairs (N = 409) were recruited through community advertising; the adolescents ranged from 12 to 16 years old and 64 % were female. Mothers and adolescents completed baseline and 6-month follow-up telephone interviews. Booklet completion in the treatment group ranged from 80 % for the first to 62 % for the last booklet. The analyses first tested whether program effects on dating abuse varied by four a priori identified moderators (mother's psychological health, the amount of adolescent exposure to domestic violence, and adolescent sex and race/ethnicity). Main effects of the program were examined when there were no differential program effects. Program effects on psychological and physical victimization and psychological and cyber perpetration were moderated by the amount of adolescent exposure to domestic violence; there were significant favorable program effects for adolescents with higher, but not lower levels of exposure to domestic violence. There were no moderated or main effects on sexual violence victimization and perpetration or cyber victimization. The findings suggest that a dating abuse prevention program designed for adolescents exposed to domestic violence can have important positive effects.

Study of runaway electron generation during major disruptions in JET

Czech Academy of Sciences Publication Activity Database

Plyusnin, V.V.; Riccardo, V.; Jaspers, R.; Alper, B.; Kiptily, V.G.; Mlynář, Jan; Popovichev, S.; de La Luna, E.; Andersson, F.

2006-01-01

Roč. 46, č. 2 (2006), s. 277-284 ISSN 0029-5515 Institutional research plan: CEZ:AV0Z2043910 Keywords : JET * tokamak * fusion * dicsruption * runaway electrons * tomography Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.839, year: 2006

Masculinity, vulnerability and prevention of STD/HIV/AIDS among male adolescents: social representations in a land reform settlement

Directory of Open Access Journals (Sweden)

Camila de Oliveira Arraes

2013-12-01

Full Text Available OBJECTIVE: to analyze the relationship of masculinity, vulnerability and prevention of STD / HIV / AIDS among adolescent males of a land reform settlement in central Brazil. METHOD: a qualitative study using as precepts the strands of social representations with teenagers between 12 to 24 years. RESULTS: three categories emerged - Perception of vulnerability; Gender and vulnerability; and, Prevention and vulnerability to STD / HIV / AIDS. Adolescents felt invulnerable to sexually transmitted diseases anchored in the social representations in favor of the male hegemony. An ignorance about forms of prevention for STD / HIV / AIDS was demonstrated in their statements. It is believed that institutional projects such as the School Health Program and the Men's Health Care Program constitute essential tools to minimize factors of vulnerability in this population, since the school is recognized as a social facility that promotes socialization of experiences and contributes to the construction of the identity of the adolescent. CONCLUSION: the social representations of masculinity collaborate for the vulnerable behavior of the adolescents for the acquisition of sexually transmitted diseases. One hopes that this study can contribute to the production of knowledge and technical-scientific improvement of the professionals, especially the nurse, in order to discuss issues related to male sexuality of adolescents in the situation of the land reform settlement.

Masculinity, vulnerability and prevention of STD/HIV/AIDS among male adolescents: social representations in a land reform settlement.

Science.gov (United States)

Arraes, Camila de Oliveira; Palos, Marinésia Aparecida Prado; Barbosa, Maria Alves; Teles, Sheila Araujo; Souza, Márcia Maria de; Matos, Marcos André de

2013-01-01

to analyze the relationship of masculinity, vulnerability and prevention of STD / HIV / AIDS among adolescent males of a land reform settlement in central Brazil. a qualitative study using as precepts the strands of social representations with teenagers between 12 to 24 years. three categories emerged - Perception of vulnerability; Gender and vulnerability; and, Prevention and vulnerability to STD / HIV / AIDS. Adolescents felt invulnerable to sexually transmitted diseases anchored in the social representations in favor of the male hegemony. An ignorance about forms of prevention for STD / HIV / AIDS was demonstrated in their statements. It is believed that institutional projects such as the School Health Program and the Men's Health Care Program constitute essential tools to minimize factors of vulnerability in this population, since the school is recognized as a social facility that promotes socialization of experiences and contributes to the construction of the identity of the adolescent. the social representations of masculinity collaborate for the vulnerable behavior of the adolescents for the acquisition of sexually transmitted diseases. One hopes that this study can contribute to the production of knowledge and technical-scientific improvement of the professionals, especially the nurse, in order to discuss issues related to male sexuality of adolescents in the situation of the land reform settlement.

Screening for Obesity in Children and Adolescents: US Preventive Services Task Force Recommendation Statement.

Science.gov (United States)

Grossman, David C; Bibbins-Domingo, Kirsten; Curry, Susan J; Barry, Michael J; Davidson, Karina W; Doubeni, Chyke A; Epling, John W; Kemper, Alex R; Krist, Alex H; Kurth, Ann E; Landefeld, C Seth; Mangione, Carol M; Phipps, Maureen G; Silverstein, Michael; Simon, Melissa A; Tseng, Chien-Wen

2017-06-20

Based on year 2000 Centers for Disease Control and Prevention growth charts, approximately 17% of children and adolescents aged 2 to 19 years in the United States have obesity, and almost 32% of children and adolescents are overweight or have obesity. Obesity in children and adolescents is associated with morbidity such as mental health and psychological issues, asthma, obstructive sleep apnea, orthopedic problems, and adverse cardiovascular and metabolic outcomes (eg, high blood pressure, abnormal lipid levels, and insulin resistance). Children and adolescents may also experience teasing and bullying behaviors based on their weight. Obesity in childhood and adolescence may continue into adulthood and lead to adverse cardiovascular outcomes or other obesity-related morbidity, such as type 2 diabetes. Although the overall rate of child and adolescent obesity has stabilized over the last decade after increasing steadily for 3 decades, obesity rates continue to increase in certain populations, such as African American girls and Hispanic boys. These racial/ethnic differences in obesity prevalence are likely a result of both genetic and nongenetic factors (eg, socioeconomic status, intake of sugar-sweetened beverages and fast food, and having a television in the bedroom). To update the 2010 US Preventive Services Task Force (USPSTF) recommendation on screening for obesity in children 6 years and older. The USPSTF reviewed the evidence on screening for obesity in children and adolescents and the benefits and harms of weight management interventions. Comprehensive, intensive behavioral interventions (≥26 contact hours) in children and adolescents 6 years and older who have obesity can result in improvements in weight status for up to 12 months; there is inadequate evidence regarding the effectiveness of less intensive interventions. The harms of behavioral interventions can be bounded as small to none, and the harms of screening are minimal. Therefore, the USPSTF

On the synchrotron emission in kinetic simulations of runaway electrons in magnetic confinement fusion plasmas

Science.gov (United States)

Carbajal, L.; del-Castillo-Negrete, D.

2017-12-01

Developing avoidance or mitigation strategies of runaway electrons (REs) in magnetic confinement fusion (MCF) plasmas is of crucial importance for the safe operation of ITER. In order to develop these strategies, an accurate diagnostic capability that allows good estimates of the RE distribution function in these plasmas is needed. Synchrotron radiation (SR) of RE in MCF, besides of being one of the main damping mechanisms for RE in the high energy relativistic regime, is routinely used in current MCF experiments to infer the parameters of RE energy and pitch angle distribution functions. In the present paper we address the long standing question about what are the relationships between different REs distribution functions and their corresponding synchrotron emission simultaneously including: full-orbit effects, information of the spectral and angular distribution of SR of each electron, and basic geometric optics of a camera. We study the spatial distribution of the SR on the poloidal plane, and the statistical properties of the expected value of the synchrotron spectra of REs. We observe a strong dependence of the synchrotron emission measured by the camera on the pitch angle distribution of runaways, namely we find that crescent shapes of the spatial distribution of the SR as measured by the camera relate to RE distributions with small pitch angles, while ellipse shapes relate to distributions of runaways with larger the pitch angles. A weak dependence of the synchrotron emission measured by the camera with the RE energy, value of the q-profile at the edge, and the chosen range of wavelengths is observed. Furthermore, we find that oversimplifying the angular dependence of the SR changes the shape of the synchrotron spectra, and overestimates its amplitude by approximately 20 times for avalanching runaways and by approximately 60 times for mono-energetic distributions of runaways1.

Massive runaway stars in the Small Magellanic Cloud

Science.gov (United States)

Gvaramadze, V. V.; Pflamm-Altenburg, J.; Kroupa, P.

2011-01-01

Using archival Spitzer Space Telescope data, we identified for the first time a dozen runaway OB stars in the Small Magellanic Cloud (SMC) through the detection of their bow shocks. The geometry of detected bow shocks allows us to infer the direction of motion of the associated stars and to determine their possible parent clusters and associations. One of the identified runaway stars, AzV 471, was already known as a high-velocity star on the basis of its high peculiar radial velocity, which is offset by ≃ 40 km s-1 from the local systemic velocity. We discuss implications of our findings for the problem of the origin of field OB stars. Several of the bow shock-producing stars are found in the confines of associations, suggesting that these may be “alien” stars contributing to the age spread observed for some young stellar systems. We also report the discovery of a kidney-shaped nebula attached to the early WN-type star SMC-WR3 (AzV 60a). We interpreted this nebula as an interstellar structure created owing to the interaction between the stellar wind and the ambient interstellar medium.

African-American and Latino Parents��� Attitudes and Beliefs Regarding Adolescent Fighting and Its Prevention

OpenAIRE

Chen, RuiJun; Flores, Glenn; Shetgiri, Rashmi

2015-01-01

Adolescent fighting affects 25% of youth, with the highest rates among African-Americans and Latinos but little is known about parental views on youth fighting. The purpose of this study was to examine African-American and Latino parents��� perspectives on adolescent fighting and methods to prevent fighting. We conducted four focus groups with parents of African-American and Latino urban adolescents. Focus groups were stratified by race/ethnicity and fighting status. Groups were audiotaped, t...

A parenting programme to prevent abuse of adolescents in South Africa: study protocol for a randomized controlled trial

OpenAIRE

Cluver, L; Meinck, F; Shenderovich, Y; Ward, CL; Herrero Romero, R; Lombard, C; Doubt, JS; Steinert, J; Catanho, R; Wittesaele, C; DeStone, S; Salah, N; Mpimilashe, P; Lachman, J; Loening, H

2016-01-01

Background An estimated one billion children experience child abuse each year, with the highest rates in low- and middle-income countries. The Sinovuyo Teen programme is part of Parenting for Lifelong Health, a WHO/UNICEF initiative to develop and test violence-prevention programmes for implementation in low-resource contexts. The objectives of this parenting support programme are to prevent the abuse of adolescents, improve parenting and reduce adolescent behavioural problems. This trial aim...

Translating models of antisocial behavioral development into efficacious intervention policy to prevent adolescent violence.

Science.gov (United States)

Dodge, Kenneth A; McCourt, Sandra N

2010-04-01

Adolescent chronic antisocial behavior is costly but concentrated in a relatively small number of individuals. The search for effective preventive interventions draws from empirical findings of three kinds of gene-by-environment interactions: (1) parenting behaviors mute the impact of genes; (2) genes alter the impact of traumatic environmental experiences such as physical abuse and peer social rejection; and (3) individuals and environments influence each other in a dynamic developmental cascade. Thus, environmental interventions that focus on high-risk youth may prove effective. The Fast Track intervention and randomized controlled trial are described. The intervention is a 10-year series of efforts to produce proximal change in parenting, peer relations, social cognition, and academic performance in order to lead to distal prevention of adolescent conduct disorder. Findings indicate that conduct disorder cases can be prevented, but only in the highest risk group of children. Implications for policy are discussed. (c) 2010 Wiley Periodicals, Inc.

The caries-preventive effect of chlorhexidine varnish in children and adolescents: a systematic review.

LENUS (Irish Health Repository)

James, Patrice

2010-01-01

Our purpose was to systematically review the literature on the effectiveness of chlorhexidine varnish for preventing dental caries in children and adolescents and to determine its effectiveness compared to fluoride varnish.

Tobacco use among adolescents. Strategies for prevention.

Science.gov (United States)

Epps, R P; Manley, M W; Glynn, T J

1995-04-01

Tobacco use is a major public health problem that has its onset during childhood and adolescence. To prevent the onset, physicians can reach children and their parents in their offices beginning in the prenatal period and continuing through adulthood. For pediatricians and other physicians who care for children, NCI recommends five office-based activities that begin with the letter A. The 5 As include anticipatory guidance, ask, advise, assist, and arrange follow-up visits. Elimination of tobacco use requires a comprehensive strategy that includes health professional interventions, policy changes, advertising restrictions, comprehensive school-based programs, community activities, and advocacy approaches. Physicians and health professionals have major roles to play in each of these interventions.

Prevention for child and adolescent psychiatry in low-resource settings

OpenAIRE

Rachna Bhargava; Anamika Sahu; Debabani Bhattacharya

2017-01-01

Preventive measures for mental health issues among children have received meager attention. Although the prevalence rates of mental disorders are significant, systematic focused efforts toward management specifically in this special population in low-resources settings have been markedly inconsequential. Certainly, unlike other medical conditions, policies, and services related to mental health of children and adolescent are not adequate and efficient to deal with the burden of mental disorde...

Measurements of fluctuations in the flux of runaway electrons to the PLT limiter

International Nuclear Information System (INIS)

Barnes, C.W.; Strachan, J.D.

1982-07-01

Fluctuations in the flux of runaway electrons to the limiter have been measured during many PLT discharges. Oscillations at 60, 120, and 720 Hz are driven by variations in the vertical magnetic field which moves the plasma major radius. Fluctuations are seen in the range of 2 → 20 kHz due to MHD magnetic islands which extend to the plasma surface. A continuous spectrum of fluctuations is observed up to 200 kHz which correlates with drift-wave turbulence. The magnitude of the driven fluctuations can be used to measure transport properties of the runaway electrons. The amplitude of electron motion due to the MHD and drift-wave oscillations, and hence a measure of the radial size of the instability, can be determined as a function of frequency. The slope of the frequency power spectrum of the drift-wave-induced fluctuations steepens with increasing runaway electron drift orbit displacement during the current drop at the end of the discharge, and as the power in the MHD oscillations increases. A magnetic probe was used to confirm the presence of oscillating magnetic fields capable of perturbing the electron orbits

Health Beliefs Related to Diabetes Mellitus Prevention among Adolescents in Saudi Arabia

Directory of Open Access Journals (Sweden)

Reem L. Al-Mutairi

2015-08-01

Full Text Available Objectives: The incidence of type 2 diabetes mellitus (T2DM is growing rapidly in the Saudi population. The purpose of this study was to assess the constructs of the health belief model (HBM as they relate to T2DM lifestyle and prevention behaviours among adolescents. Methods: A cross-sectional study was conducted between May and October 2013 among 426 non-diabetic secondary school students from randomly selected schools in Riyadh, Saudi Arabia. An Arabic version of an adapted English language questionnaire was used to assess knowledge and attitudes related to the severity and prevention of T2DM. A preventative behaviour assessment was also conducted to assess physical activity and dietary habits. Results: The majority of the students (63.4% had at least one diabetic family member. Obesity was more frequent in males compared to females (P = 0.013. Awareness about the importance of maintaining a healthy body weight to prevent T2DM was lower in males than females (P = 0.037, although males engaged in routine exercise more often (P = 0.001. Males were less likely than females to recognise the risks for T2DM, including obesity (P = 0.030, heredity (P = 0.013 and high fat intake (P = 0.001. Conclusion: An alarmingly high number of Saudi students were unaware of T2DM severity and associated risk factors. Female students were more aware of the benefits of T2DM preventative lifestyle behaviours than males, although males engaged in routine exercise more often. Raising adolescents’ awareness about the primary prevention strategies for T2DM should be a public health priority in Saudi Arabia. The HBM could inform further research on diabetes prevention among Saudi adolescents.

The effectiveness of injury-prevention programs in reducing the incidence of anterior cruciate ligament sprains in adolescent athletes.

Science.gov (United States)

Paszkewicz, Jeffrey; Webb, Tristen; Waters, Brian; Welch McCarty, Cailee; Van Lunen, Bonnie

2012-11-01

There is a high incidence of anterior cruciate ligament (ACL) injury in adolescents participating in pivoting sports such as soccer, basketball, and handball. Most ACL injuries in athletes are noncontact injuries, with a mechanism of sudden deceleration, change in direction, or landing from a jump. These mechanisms coupled with an increase in contraction of the quadriceps have been shown as risk factors for ACL injuries. Injuries to the ACL may require surgery, a long rehabilitation, and the potential for reinjury. Studies have shown reductions in lower extremity injury rates using training protocols that focus on landing mechanics, balance training, strength training, and/or agility training. There has been some thought that starting preventive training programs with adolescent athletes may be the most effective approach to reducing adolescent ACL injuries. Can lower extremity injury-prevention programs effectively reduce ACL injury rates in adolescent athletes?

Gang Involvement and Membership among Homeless and Runaway Youth.

Science.gov (United States)

Yoder, Kevin A.; Whitbeck, Les B.; Hoyt, Dan R.

2003-01-01

Assessed the extent of gang involvement among homeless and runaway youth, comparing gang members, gang-involved youth (not members), and non-gang youth on several dimensions. Interview data indicated that 15.4 percent of the youth were gang members and 32.2 percent were involved in gangs. These youth reported more family problems and school…

An Online Drug Abuse Prevention Program for Adolescent Girls: Posttest and 1-Year Outcomes.

Science.gov (United States)

Schwinn, Traci M; Schinke, Steven P; Hopkins, Jessica; Keller, Bryan; Liu, Xiang

2018-03-01

Early adolescent girls' rates of drug use have matched, and in some instances, surpassed boys' rates. Though girls and boys share risk factors for drug use, girls also have gender-specific risks. Tailored interventions to prevent girls' drug use are warranted. This study developed and tested a web-based, drug abuse prevention program for adolescent girls. The nationwide sample of 13- and 14-year-old girls (N = 788) was recruited via Facebook ads. Enrolled girls were randomly assigned to the intervention or control condition. All girls completed pretest measures online. Following pretest, intervention girls interacted with the 9-session, gender-specific prevention program online. The program aimed to reduce girls' drug use and associated risk factors by improving their cognitive and behavioral skills around such areas as coping with stress, managing mood, maintaining a healthy body image, and refusing drug use offers. Girls in both conditions again completed measures at posttest and 1-year follow-up. At posttest, and compared to girls in the control condition, girls who received the intervention smoked fewer cigarettes and reported higher self-esteem, goal setting, media literacy, and self-efficacy. At 1-year follow-up, and compared to girls in the control condition, girls who received the intervention reported engaging in less binge drinking and cigarette smoking; girls assigned to the intervention condition also had higher alcohol, cigarette, and marijuana refusal skills, coping skills, and media literacy and lower rates of peer drug use. This study's findings support the use of tailored, online drug abuse prevention programming for early adolescent girls.

Common elements of adolescent prevention programs: minimizing burden while maximizing reach.

Science.gov (United States)

Boustani, Maya M; Frazier, Stacy L; Becker, Kimberly D; Bechor, Michele; Dinizulu, Sonya M; Hedemann, Erin R; Ogle, Robert R; Pasalich, Dave S

2015-03-01

A growing number of evidence-based youth prevention programs are available, but challenges related to dissemination and implementation limit their reach and impact. The current review identifies common elements across evidence-based prevention programs focused on the promotion of health-related outcomes in adolescents. We reviewed and coded descriptions of the programs for common practice and instructional elements. Problem-solving emerged as the most common practice element, followed by communication skills, and insight building. Psychoeducation, modeling, and role play emerged as the most common instructional elements. In light of significant comorbidity in poor outcomes for youth, and corresponding overlap in their underlying skills deficits, we propose that synthesizing the prevention literature using a common elements approach has the potential to yield novel information and inform prevention programming to minimize burden and maximize reach and impact for youth.

Prevention of adolescent substance abuse through the development of personal and social competence.

Science.gov (United States)

Botvin, G J

1983-01-01

The initiation of substance use typically begins during adolescence and appears to be the result of the complex interplay of social, personality, cognitive, attitudinal, behavioral, and developmental factors. Traditional smoking, alcohol, and drug education programs have attempted to increase students' knowledge of the risks associated with using these substances in the hope that this would deter use. Other programs have attempted to enrich the personal and social development of students through what has been referred to as "affective" education. Unfortunately, the inescapable conclusion to be drawn from the substance abuse prevention literature is that few of these programs have demonstrated any degree of success in terms of the actual prevention of substance use/abuse. Traditional educational approaches to substance abuse prevention appear to be inadequate because they are based on faulty assumptions and are too narrow in their focus. The "affective" education approaches, on the other hand, appear to have placed too little emphasis on the acquisition of the kind of skills that are likely to increase general personal competence and enable students to cope with the various interpersonal and intrapersonal pressures to begin using tobacco, alcohol, or drugs. From the perspective of social learning theory (Bandura 1977) and problem behavior theory (Jessor and Jessor 1977), substance use is conceptualized as a socially learned, purposive, and functional behavior which is the result of the interplay of social (environmental) and personal factors. One potentially effective approach to substance abuse prevention might involve enhancing general personal competence and teaching adolescents the kind of problem-specific skills and knowledge which will increase their ability to resist the various forms of pro-substance-use social pressure. Brief reviews of the social skills training literature and the literature related to techniques for coping with anxiety not only provide

Determination of the parametric region in which runaway electron energy losses are dominated by bremsstrahlung radiation in tokamaks

International Nuclear Information System (INIS)

Fernandez-Gomez, I.; Martin-Solis, J. R.; Sanchez, R.

2007-01-01

It has been recently argued that, at sufficiently large parallel electric fields, bremsstrahlung radiation can greatly reduce the maximum energy that runaway electrons can gain in tokamaks [M. Bakhtiari et al., Phys. Plasmas 12, 102503 (2005)]. In this contribution, the work of these authors is extended to show that the region where bremsstrahlung radiation dominate runaway energy losses is however more restricted than reported by them. Expressions will be provided for the limits of this region within the parameter space spanned by the background density and parallel electric field, as a function of the rest of the plasma parameters. It will be shown that the background density has to be above a certain critical value and that the parallel electric field must lie within a range of values, below and above which synchrotron radiation dominate the runaway energy losses. Finally, it will be demonstrated that typical disruption parameters lie within this region and, as a result, bremsstrahlung losses still play an important role in controlling the runaway energy

Reducing HIV and AIDS through Prevention (RHAP): a theoretically based approach for teaching HIV prevention to adolescents through an exploration of popular music.

Science.gov (United States)

Boutin-Foster, Carla; McLaughlin, Nadine; Gray, Angela; Ogedegbe, Anthony; Hageman, Ivan; Knowlton, Courtney; Rodriguez, Anna; Beeder, Ann

2010-05-01

Using popular culture to engage students in discussions of HIV prevention is a nontraditional approach that may complement current prevention efforts and enhance the ability to reach youth who are at high risk of contracting HIV and other sexually transmitted infections. Hip-hop or rap music is the dominant genre of music among adolescents, especially Black and Latino youth who are disproportionately impacted by HIV and AIDS. This paper describes the rationale and development of the Reducing HIV and AIDS through Prevention (RHAP) program, a school-based program that uses hip-hop/rap music as a vehicle for raising awareness among adolescents about HIV/AIDS. Constructs from the Social Cognitive Theory and the Sexual Script Theory were used in developing the program. It was piloted and evaluated among 26 middle school students in East Harlem, New York. The lessons learned from a formative evaluation of the program and the implications for developing other programs targeting public health problems are discussed. The RHAP program challenges the traditional pedagogue-student paradigm and provides an alternative approach to teaching about HIV prevention and awareness.

LP 543-25: A Rare Low-mass Runaway Disk Star

Science.gov (United States)

de la Fuente Marcos, Raúl; de la Fuente Marcos, Carlos

2018-05-01

LP 543-25 or PSS 544-7 is a high proper-motion star located 458 pc from the Sun in the constellation of Canis Minor; it has been argued that it could be a candidate cannonball star ejected by a star cluster. Here, we revisit the issue of the kinematics of this interesting star using Gaia DR2. The heliocentric Galactic velocity components are (U, V, W) = (206, -289, 30) km/s; the corresponding Galactocentric Galactic velocity components show that LP 543-25 is moving in the Galactic plane and away from the Galactic Center at a rate of nearly 200 km/s, which is compatible with an origin in one of the multiple star clusters that inhabit the inner regions of the Milky Way. LP 543-25 appears to be a member of an elusive class of stars, the low-mass runaway stars. It is perhaps one of the closest and less massive runaway stars identified so far.

Runaway beam studies during disruptions at JET-ILW

Czech Academy of Sciences Publication Activity Database

Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Brezinsek, S.; Decker, J.; Devaux, S.; de Vries, P.; Fil, A.; Gerasimov, S.; Lupelli, I.; Jachmich, S.; Khilkevitch, E.M.; Kiptily, V.; Koslowski, R.; Kruezi, U.; Lehnen, M.; Manzanares, A.; Mlynář, Jan; Nardon, E.; Nilsson, E.; Riccardo, V.; Saint-Laurent, F.; Shevelev, A.E.; Sozzi, C.

2015-01-01

Roč. 463, August (2015), s. 143-149 ISSN 0022-3115. [PLASMA-SURFACE INTERACTIONS 21: International Conference on Plasma-Surface Interactions in Controlled Fusion Devices. Kanazawa, 26.05.2014-30.05.2014] Institutional support: RVO:61389021 Keywords : tokamak * JET * runaway electrons * disruptions * ILW Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 2.199, year: 2015 http://www.sciencedirect.com/science/article/pii/S0022311514006850

Conceptual design of the radial gamma ray spectrometers system for α particle and runaway electron measurements at ITER

Science.gov (United States)

Nocente, M.; Tardocchi, M.; Barnsley, R.; Bertalot, L.; Brichard, B.; Croci, G.; Brolatti, G.; Di Pace, L.; Fernandes, A.; Giacomelli, L.; Lengar, I.; Moszynski, M.; Krasilnikov, V.; Muraro, A.; Pereira, R. C.; Perelli Cippo, E.; Rigamonti, D.; Rebai, M.; Rzadkiewicz, J.; Salewski, M.; Santosh, P.; Sousa, J.; Zychor, I.; Gorini, G.

2017-07-01

We here present the principles and main physics capabilities behind the design of the radial gamma ray spectrometers (RGRS) system for alpha particle and runaway electron measurements at ITER. The diagnostic benefits from recent advances in gamma-ray spectrometry for tokamak plasmas and combines space and high energy resolution in a single device. The RGRS system as designed can provide information on α ~ particles on a time scale of 1/10 of the slowing down time for the ITER 500 MW full power DT scenario. Spectral observations of the 3.21 and 4.44 MeV peaks from the 9\\text{Be}≤ft(α,nγ \\right){{}12}\\text{C} reaction make the measurements sensitive to α ~ particles at characteristic resonant energies and to possible anisotropies of their slowing down distribution function. An independent assessment of the neutron rate by gamma-ray emission is also feasible. In case of runaway electrons born in disruptions with a typical duration of 100 ms, a time resolution of at least 10 ms for runaway electron studies can be achieved depending on the scenario and down to a current of 40 kA by use of external gas injection. We find that the bremsstrahlung spectrum in the MeV range from confined runaways is sensitive to the electron velocity space up to E≈ 30 -40 MeV, which allows for measurements of the energy distribution of the runaway electrons at ITER.

Mother-Child Conflict and Its Moderating Effects on Depression Outcomes in a Preventive Intervention for Adolescent Depression

Science.gov (United States)

Young, Jami F.; Gallop, Robert; Mufson, Laura

2009-01-01

This article reports on mother-child conflict as an outcome and moderator of Interpersonal Psychotherapy-Adolescent Skills Training (IPT-AST), a preventive intervention for depression. Forty-one adolescents (average age = 13.37, SD = 1.19) with elevated depression symptoms were randomized to receive IPT-AST or school counseling (SC). Adolescents…

Domestic violence among adolescents in HIV prevention research in Tanzania: Participant experiences and measurement issues

Science.gov (United States)

Baumgartner, Joy Noel; Kaaya, Sylvia; Karungula, Happy; Kaale, Anna; Headley, Jennifer; Tolley, Elizabeth

2014-01-01

Objectives Under-representation of female adolescents in HIV clinical trials may inhibit their access to future prevention technologies. Domestic violence, broadly defined as violence perpetrated by intimate partners and/or family members, may affect trial participation. This study describes violence in the lives of adolescents and young women in Tanzania, explores use of the Women’s Experience with Battering (WEB) Scale to measure battering, and examines the associations between battering and socio-demographic and HIV risk factors. Methods Community formative research (CFR) and a mock clinical trial (MCT) were conducted to examine the challenges of recruiting younger (15-17) versus older (18-21) participants into HIV prevention trials. The CFR included qualitative interviews with 23 participants and there were 135 MCT participants. The WEB was administered in both the CFR and MCT. Results Nineteen CFR participants experienced physical/sexual violence and 17% scored positive for battering. All married participants reported partner-related domestic violence, and half scored positive for battering. Many believed beatings were normal. None of the single participants scored positive on battering, but one-third reported abuse by relatives. Among MCT participants, 15% scored positive for battering; most perpetrators were relatives. Younger participants were more likely to report battering. Conclusions Adolescents experienced high rates of domestic violence and the WEB captured battering from both partners and relatives. The level of familial violence was unexpected and has implications for parental roles in study recruitment. Addressing adolescent abuse in HIV prevention trials and in the general population should be a public health priority. PMID:24740725

Towards an integration of positive and sickness paradigms in the prevention of eating disorders in adolescents

Directory of Open Access Journals (Sweden)

Vanesa C. Góngora

2015-09-01

Full Text Available Eating disorders problems are highly relevant in adolescence and require intervention through the implementation of prevention and promotion health programs. A Few primary prevention programmers to fight eating disorders have reached satisfactory results. The most successful results have been obtained with approaches that promote media literacy, the use of cognitive dissonance and the enhancement of self-esteem. Since many of the programs based on the disease model have failed to prevent such difficulties, the prevention of eating disorders may be improved by taking the contributions of positive psychology. Studies have shown that interventions based on this paradigm are effective to increase the feeling of happiness and subjective well-being. Unlike the traditional approach that works with the identification of risk and protective factors, positive psychology emphasizes the identification and promotion of healthy factors. Positive interventions assume that strengthening the positive, the dysfunctional or negative will be diminished. The integration of both contributions will enrich the approach to promote healthy behavior in adolescents.

Numerical study of the generation of runaway electrons in a gas diode with a hot channel

Energy Technology Data Exchange (ETDEWEB)

Lisenkov, V. V., E-mail: lisenkov@iep.uran.ru [Institute of Electrophysics UrB RAS, 106 Amundsena St., Ekaterinburg 620012 (Russian Federation); Ural Federal University, 19 Mira St., Ekaterinburg 620002 (Russian Federation); Shklyaev, V. A., E-mail: shklyaev@to.hcei.tsc.ru [Institute of High Current Electronics SD RAS, 2/3 Akademichesky Avenue, 634055 Tomsk (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Avenue, 634050 Tomsk (Russian Federation)

2015-11-15

A new method for increasing the efficiency of runaway electron beam generation in atmospheric pressure gas media has been suggested and theoretically proved. The method consists of creating a hot region (e.g., a spark channel or a laser plume) with a decreased numerical density of gas molecules (N) near the cathode. In this method, the ratio E/N (E—electric field strength) is increased by decreasing N instead of increasing E, as has been done in the past. The numerical model that is used allows the simultaneous calculation of the formation of a subnanosecond gas discharge and the generation of runaway electrons in gas media. The calculations have demonstrated the possibility of obtaining current pulses of runaway electrons with amplitudes of hundred of amperes and durations of more than 100 ps. The influence of the hot channel geometry on the parameters of the generated beam has been investigated.

Health Promotion for Adolescent Childhood Leukemia Survivors: Building on Prevention Science and eHealth

Science.gov (United States)

Elliot, Diane L.; Lindemulder, Susan J.; Goldberg, Linn; Stadler, Diane D.; Smith, Jennifer

2014-01-01

Teenage survivors of childhood acute lymphoblastic leukemia (ALL) have increased morbidity likely due to their prior multicomponent treatment. Habits established in adolescence can impact individuals’ subsequent adult behaviors. Accordingly, healthy lifestyles, avoiding harmful actions, and appropriate disease surveillance are of heightened importance among teenage survivors. We review the findings from prevention science and their relevance to heath promotion. The capabilities and current uses of eHealth components including e-learning, serious video games, exergaming, behavior tracking, individual messaging, and social networking are briefly presented. The health promotion needs of adolescent survivors are aligned with those eHealth aspects to propose a new paradigm to enhance the wellbeing of adolescent ALL survivors. PMID:23109253

Preventing substance use among early Asian-American adolescent girls: initial evaluation of a web-based, mother-daughter program.

Science.gov (United States)

Fang, Lin; Schinke, Steven P; Cole, Kristin C A

2010-11-01

This study examined the efficacy and generalizability of a family-oriented, web-based substance use prevention program to young Asian-American adolescent girls. Between September and December 2007, a total of 108 Asian-American girls aged 10-14 years and their mothers were recruited through online advertisements and from community service agencies. Mother-daughter dyads were randomly assigned to an intervention arm or to a test-only control arm. After pretest measurement, intervention-arm dyads completed a 9-session web-based substance use prevention program. Guided by family interaction theory, the program aimed to improve girls' psychological states, strengthen substance use prevention skills, increase mother-daughter interactions, enhance maternal monitoring, and prevent girls' substance use. Study outcomes were assessed using generalized estimating equations. At posttest, relative to control-arm girls, intervention-arm girls showed less depressed mood; reported improved self-efficacy and refusal skills; had higher levels of mother-daughter closeness, mother-daughter communication, and maternal monitoring; and reported more family rules against substance use. Intervention-arm girls also reported fewer instances of alcohol, marijuana, and illicit prescription drug use, and expressed lower intentions to use substances in the future. A family-oriented, web-based substance use prevention program was efficacious in preventing substance use behavior among early Asian-American adolescent girls. Copyright © 2010 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Communication between Asian American Adolescents and Health Care Providers about Sexual Activity, Sexually Transmitted Infections, and Pregnancy Prevention

Science.gov (United States)

Zhao, Jessie; Lau, May; Vermette, David; Liang, David; Flores, Glenn

2017-01-01

Asian American adolescents have been reported to have the lowest amount of communication with health care providers regarding sexual health topics (sexual activity, contraception, sexually transmitted infections, and pregnancy prevention). This study identified Asian American adolescents' attitudes/beliefs regarding how health care providers can…

Density dependence triggers runaway selection of reduced senescence.

Directory of Open Access Journals (Sweden)

Robert M Seymour

2007-12-01

Full Text Available In the presence of exogenous mortality risks, future reproduction by an individual is worth less than present reproduction to its fitness. Senescent aging thus results inevitably from transferring net fertility into younger ages. Some long-lived organisms appear to defy theory, however, presenting negligible senescence (e.g., hydra and extended lifespans (e.g., Bristlecone Pine. Here, we investigate the possibility that the onset of vitality loss can be delayed indefinitely, even accepting the abundant evidence that reproduction is intrinsically costly to survival. For an environment with constant hazard, we establish that natural selection itself contributes to increasing density-dependent recruitment losses. We then develop a generalized model of accelerating vitality loss for analyzing fitness optima as a tradeoff between compression and spread in the age profile of net fertility. Across a realistic spectrum of senescent age profiles, density regulation of recruitment can trigger runaway selection for ever-reducing senescence. This novel prediction applies without requirement for special life-history characteristics such as indeterminate somatic growth or increasing fecundity with age. The evolution of nonsenescence from senescence is robust to the presence of exogenous adult mortality, which tends instead to increase the age-independent component of vitality loss. We simulate examples of runaway selection leading to negligible senescence and even intrinsic immortality.

Developing a Web-Based Intervention to Prevent Drug Use among Adolescent Girls

Science.gov (United States)

Schwinn, Traci Marie; Hopkins, Jessica Elizabeth; Schinke, Steven Paul

2016-01-01

Objectives: Girls' rates of drug use have met up with and, in some instances, surpassed boys' rates. Although girls and boys share risk and protective factors associated with drug use, girls also have gender-specific risks. Interventions to prevent girls' drug use must be tailored to address the dynamics of female adolescence. Methods: One such…

Strategically Timed Preventive Education and Media Strategies Reduce Seasonal Trends in Adolescent Conception.

Science.gov (United States)

Gauster, A; Waddington, A; Jamieson, M A

2015-08-01

This study sought to analyze the effect of strategically timed local preventive education on reducing teen conception rates during known seasonal peaks in March and April. All teen conceptions (age ≤ 19) from March and April 2010, 2011, and 2012 were identified using medical records data. Teen conceptions occurring in January 2010, 2011, and 2012 were also identified to control for any new trends in the community. A city of 160,000 with 1 tertiary care centre. Pregnant adolescents (age ≤ 19). During the month of February 2012, preventive education and media awareness strategies were aimed at parents, teachers, and teens. Adolescent conceptions in March and April 2012. Conception rates in teens ≤18 years old were significantly reduced in March and April 2012 compared to March and April 2010 and 2011 (RR = 0.53, 95% CI = 0.32 - 0.88, P = .0132). There was an increase in conceptions in March and April 2012 compared to 2010 and 2011 among 19-year-olds (RR = 1.57, 95% CI = 0.84-2.9, P = .1500). Effect modification revealed our ≤18-year-old group and our 19-year-old group were distinct groups with different risk estimates (P = .0075). Educational sessions were poorly attended and contraception clinic volume was static. We propose increased parental supervision in response to media reminders as a possible explanation for the reduction in adolescent conceptions (≤18 years old) seen in March 2012. Copyright © 2015 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Adolescents' responses to a school-based prevention program promoting healthy eating at school

NARCIS (Netherlands)

Hermans, R.C.J.; Bruin, H. de; Larsen, J.K.; Mensink, F.; Hoek, A.C.

2017-01-01

Background: To improve the effectiveness of school-based obesity prevention programs, it is essential to understand the views and behaviors of the target group. The present study aimed to get a better understanding of adolescents' food and health perceptions and their willingness to be involved in a

Runaway tails in magnetized plasmas

Science.gov (United States)

Moghaddam-Taaheri, E.; Vlahos, L.; Rowland, H. L.; Papadopoulos, K.

1985-01-01

The evolution of a runaway tail driven by a dc electric field in a magnetized plasma is analyzed. Depending on the strength of the electric field and the ratio of plasma to gyrofrequency, there are three different regimes in the evolution of the tail. The tail can be (1) stable with electrons accelerated to large parallel velocities, (2) unstable to Cerenkov resonance because of the depletion of the bulk and the formation of a positive slope, (3) unstable to the anomalous Doppler resonance instability driven by the large velocity anisotropy in the tail. Once an instability is triggered (Cerenkov or anomalous Doppler resonance) the tail relaxes into an isotropic distribution. The role of a convection type loss term is also discussed.

Adolescent Female Text Messaging Preferences to Prevent Pregnancy After an Emergency Department Visit: A Qualitative Analysis.

Science.gov (United States)

Chernick, Lauren Stephanie; Schnall, Rebecca; Stockwell, Melissa S; Castaño, Paula M; Higgins, Tracy; Westhoff, Carolyn; Santelli, John; Dayan, Peter S

2016-09-29

Over 15 million adolescents use the emergency department (ED) each year in the United States. Adolescent females who use the ED for medical care have been found to be at high risk for unintended pregnancy. Given that adolescents represent the largest users of text messaging and are receptive to receiving text messages related to their sexual health, the ED visit represents an opportunity for intervention. The aim of this qualitative study was to explore interest in and preferences for the content, frequency, and timing of an ED-based text message intervention to prevent pregnancy for adolescent females. We conducted semistructured, open-ended interviews in one urban ED in the United States with adolescent females aged 14-19 years. Eligible subjects were adolescents who were sexually active in the past 3 months, presented to the ED for a reproductive health complaint, owned a mobile phone, and did not use effective contraception. Using an interview guide, enrollment continued until saturation of key themes. The investigators designed sample text messages using the Health Beliefs Model and participants viewed these on a mobile phone. The team recorded, transcribed, and coded interviews based on thematic analysis using the qualitative analysis software NVivo and Excel. Participants (n=14) were predominantly Hispanic (13/14; 93%), insured (13/14; 93%), ED users in the past year (12/14; 86%), and frequent text users (10/14; 71% had sent or received >30 texts per day). All were interested in receiving text messages from the ED about pregnancy prevention, favoring messages that were "brief," "professional," and "nonaccusatory." Respondents favored texts with links to websites, repeated information regarding places to receive "confidential" care, and focused information on contraception options and misconceptions. Preferences for text message frequency varied from daily to monthly, with random hours of delivery to maintain "surprise." No participant feared that text

Analyses of electron runaway in front of the negative streamer channel

DEFF Research Database (Denmark)

Babich, L. P.; Bochkov, E. I.; Kutsyk, I. M.

2017-01-01

X-and γ-ray emissions, observed in correlation with negative leaders of lightning and long sparks of high-voltage laboratory experiments, are conventionally connected with the bremsstrahlung of high-energy runaway electrons (REs). Here we extend a focusing mechanism, analyzed in our previous paper...

Cross-cultural adaptation of an adolescent HIV prevention program: social validation of social contexts and behavior among Botswana adolescents.

Science.gov (United States)

St Lawrence, Janet S; Seloilwe, Esther; Magowe, Mabel; Dithole, Kefalotse; Kgosikwena, Billy; Kokoro, Elija; Lesaane, Dipuo

2013-08-01

An evidence-based HIV prevention intervention was adapted for Botswana youth with qualitative interviews, input from an adolescent panel, and social validation. Qualitative interviews were conducted with 40 boys and girls ages 13-19. An adolescent panel then drafted scenarios reflecting social situations described in the interviews that posed risk for HIV. A social validation sample (N = 65) then indicated the prevalence and difficulty of each situation. Youth described informational needs, pressures to use alcohol and drugs, peer pressure for unprotected sex, and intergenerational sex initiations as risk-priming situations. From 17% to 57% of the social validation sample had personally experienced the situations drafted by the adolescent panel. There were no differences in the ratings of boys versus girls, but youth over age 16 more often reported that they had experienced these risky situations. The results were embedded into the intervention. Major changes to the intervention resulted from this three-phase process.

Child and Adolescent Suicidal Behavior: School-Based Prevention, Assessment, and Intervention. Practical Intervention in the Schools Series

Science.gov (United States)

Miller, David N.

2011-01-01

Meeting a crucial need, this book distills the best current knowledge on child and adolescent suicide prevention into comprehensive guidelines for school-based practitioners. The author draws on extensive research and clinical experience to provide best-practice recommendations for developing schoolwide prevention programs, conducting risk…

Predictors of risky sexual behavior in African American adolescent girls: implications for prevention interventions.

Science.gov (United States)

Bachanas, Pamela J; Morris, Mary K; Lewis-Gess, Jennifer K; Sarett-Cuasay, Eileen J; Sirl, Kimberly; Ries, Julie K; Sawyer, Mary K

2002-09-01

To describe empirically the risky sexual behavior of an at-risk sample of adolescent girls, to assess psychosocial correlates of risky behavior, and to examine the utility of applying a risk and protective model to predicting teens' risky sexual behavior. Participants included 158 African American girls, ages 12 to 19, who were receiving medical care in an adolescent primary care clinic. Teens completed measures of depression, conduct problems, substance use, peer norms, social support, HIV knowledge, sexual self-efficacy, and sexual behavior. Teens in this sample reported high rates of risky sexual behaviors, including early sexual debuts and frequent unprotected sexual encounters with multiple partners. African American girls who reported high rates of substance use and who reported that their peers engaged in risky behaviors also reported engaging in high rates of risky sexual behaviors. Little support was obtained for protective factors (HIV knowledge, social support, sexual self-efficacy) moderating the relations between risk factors and adolescents' risky sexual behavior in this sample. Teens presenting in primary care settings in urban environments seem to be at high risk for HIV, STDs, and substance abuse, and risk reduction strategies should be introduced during the preteen years. An interdisciplinary model of care in primary care settings serving adolescents is clearly indicated, and prevention-oriented interventions aimed at reducing risky behaviors and preventing the development of more significant health, mental health, or substance abuse disorders are needed.

Examining the Preliminary Efficacy of a Dating Violence Prevention Program for Hispanic Adolescents

Science.gov (United States)

Gonzalez-Guarda, Rosa Maria; Guerra, Jessica E.; Cummings, Amanda A.; Pino, Karen; Becerra, Maria M.

2015-01-01

The purpose of this study is to evaluate the preliminary efficacy of a dating violence (DV) prevention program for Cuban American adolescents ("JOVEN"/YOUTH: "Juntos Opuestos a la Violence Entre Novios"/Together Against Dating Violence). A randomized-controlled experimental design with a delayed condition was used to evaluate…

Sex, condoms, gender roles, and HIV transmission knowledge among adolescents in León, Nicaragua: implications for HIV prevention.

Science.gov (United States)

Manji, A; Peña, R; Dubrow, R

2007-09-01

There are few peer-reviewed studies of HIV/AIDS-related knowledge, attitudes, beliefs and practices among adolescents in Central America. A population-based cross-sectional survey was conducted among 246 adolescents in León, Nicaragua, where there is reason for concern about a rise in HIV infections. In many respects, León adolescents were typical of those in other Latin American countries, with a mixture of correct and incorrect knowledge about transmission of HIV and sexually transmitted infections, a higher proportion of males than females reporting having had sex or using condoms, and inconsistent condom use. While some sexual attitudes conformed to the ideology of machismo, others did not, providing an opening for prevention interventions. Some dimensions of HIV/AIDS stigma were high, and most adolescents disapproved of same-sex sexual behaviour. Intervention against homosexuality-related stigma is particularly urgent because a concentrated HIV epidemic may be emerging in Nicaragua among men who have sex with men. Personal religious beliefs did not appear to pose a barrier to condom use. In a multivariate model, being out of school was a significant correlate of having had sex and of insufficient HIV/AIDS-related knowledge. Accordingly, HIV prevention interventions must reach adolescents both in and out of school. A multi-component approach to prevention is needed, including programmes based in schools, communities, the mass media and health facilities.

Parent-based interventions for preventing or reducing adolescent substance use: A systematic literature review

NARCIS (Netherlands)

Kuntsche, S.; Kuntsche, E.N.

2016-01-01

Despite the increasing relevance of peers, parents remain important socializing agents for their adolescent children and are therefore promising agents for inclusion in prevention or intervention programs. This systematic review provides an overview of the effectiveness of parent-based programs in

Historical context for the creation of the Office of Adolescent Health and the Teen Pregnancy Prevention Program.

Science.gov (United States)

Kappeler, Evelyn M; Farb, Amy Feldman

2014-03-01

In Fiscal Year 2010, Federal funds were dedicated to support evidence-based approaches to effectively target teen pregnancy prevention and resulted in the establishment of the Office of Adolescent Health (OAH) and the Teen Pregnancy Prevention (TPP) Program. Through the tiered TPP Program, OAH supports replication and evaluation of programs using models whose effectiveness has been demonstrated through rigorous evaluation and the development and testing of promising or innovative pregnancy prevention strategies and approaches. This article documents the creation of OAH and the development of the TPP Program, the identification of a TPP evidence base, current program and evaluation efforts at OAH, and government coordination and partnerships related to reducing teen pregnancy. This article is of interest to those working to improve the health and wellbeing of adolescents. Published by Elsevier Inc.

Sexual Health Information Seeking Online Among Runaway and Homeless Youth.

Science.gov (United States)

Barman-Adhikari, Anamika; Rice, Eric

2011-06-01

Research shows runaway and homeless youth are reluctant to seek help from traditional health providers. The Internet can be useful in engaging this population and meeting their needs for sexual health information, including information about HIV and other sexually transmitted infections (STIs). Using a sample of homeless youth living in Los Angeles, California in June 2009, this study assesses the frequency with which runaway and homeless youth seek sexual health information via the Internet, and assesses which youth are more likely to engage in seeking health information from online sources. Drawing from Andersen's (1968) health behavior model and Pescosolido's (1992) network episode model, we develop and refine a model for seeking online sexual health information among homeless youth. Rather than testing the predicative strength of a given model, our aim is to identify and explore conceptually driven correlates that may shed light on the characteristics associated with these help seeking behaviors among homeless youth. Analyses using multivariate logistic regression models reveal that among the sample of youth, females and gay males most frequently seek sexual health information online. We demonstrate the structure of social network ties (e.g., connection with parents) and the content of interactions (e.g., e-mail forwards of health information) across ties are critical correlates of online sexual health information seeking. Results show a continued connection with parents via the Internet is significantly associated with youth seeking HIV or STI information. Similarly for content of interactions, more youth who were sent health information online also reported seeking HIV information and HIV-testing information. We discuss implications for intervention and practice, focusing on how the Internet may be used for dissemination of sexual health information and as a resource for social workers to link transient, runaway, and homeless youth to care.

Social mediation of persuasive media in adolescent substance prevention.

Science.gov (United States)

Crano, William D; Alvaro, Eusebio M; Tan, Cara N; Siegel, Jason T

2017-06-01

Social commentary about prevention messages may affect their likelihood of acceptance. To investigate this possibility, student participants (N = 663) viewed 3 antimarijuana advertisements, each followed immediately by videotaped discussions involving 4 adults or 4 adolescents using either extreme or moderate language in their positive commentaries. The commentaries were expected to affect participants' perceptions of the extent to which the ads were designed to control their behavior (perceived control), which was hypothesized to inhibit persuasion. Two indirect effects analyses were conducted. Marijuana attitudes and usage intentions were the outcome variables. Both analyses revealed statistically significant source by language interactions on participants' perceived control (both p negative marijuana attitudes and diminished usage intentions when adults used moderate (vs. extreme) language in their favorable ad commentaries (both p impact of interpersonal communication variations on acceptance of media-transmitted prevention messages. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Gas explosions and thermal runaways during external heating abuse of commercial lithium-ion graphite-LiCoO2 cells at different levels of ageing

Science.gov (United States)

Larsson, Fredrik; Bertilsson, Simon; Furlani, Maurizio; Albinsson, Ingvar; Mellander, Bengt-Erik

2018-01-01

Commercial 6.8 Ah lithium-ion cells with different ageing/status have been abused by external heating in an oven. Prior to the abuse test, selected cells were aged either by C/2 cycling up to 300 cycles or stored at 60 °C. Gas emissions were measured by FTIR and three separate vents were identified, two well before the thermal runaway while the third occurred simultaneously with the thermal runaway releasing heavy smoke and gas. Emissions of toxic carbon monoxide (CO), hydrogen fluoride (HF) and phosphorous oxyfluoride (POF3) were detected in the third vent, regardless if there was a fire or not. All abused cells went into thermal runaway and emitted smoke and gas, the working cells also released flames as well as sparks. The dead cells were however less reactive but still underwent thermal runaway. For about half of the working cells, for all levels of cycle ageing, ignition of the accumulated battery released gases occurred about 15 s after the thermal runaway resulting in a gas explosion. The thermal runaway temperature, about 190 °C, varied somewhat for the different cell ageing/status where a weak local minimum was found for cells cycled between 100 and 200 times.

On-line runaway detection in batch reactors using chaos theory techniques.

NARCIS (Netherlands)

Strozzi, F.; Strozzi, F.; Zaldivar, J.M.; Zaldivar, J.M.; Kronberg, Alexandre E.; Westerterp, K.R.

1999-01-01

In this work nonlinear time-series analysis using delay coordinate embedding was applied to simulated temperature data from isoperibolic batch reactors to develop an early-warning detection system of the runaway. In the first part of this study an early-warning detection criterion, that is, when the

Strategies for the prevention of MP3-induced hearing loss among adolescents : Expert opinions from a Delphi study

NARCIS (Netherlands)

Vogel, I.; Brug, J.; Ploeg, C.P.B. van der; Raat, H.

2009-01-01

OBJECTIVE. To identify parties involved in the prevention of MP3-induced hearing loss among adolescents and potentially effective prevention strategies and interventions. METHODS. Thirty experts in fields such as scientific research, medical practice, community health professions, education, youth

The process of adapting a universal dating abuse prevention program to adolescents exposed to domestic violence.

Science.gov (United States)

Foshee, Vangie A; Dixon, Kimberly S; Ennett, Susan T; Moracco, Kathryn E; Bowling, J Michael; Chang, Ling-Yin; Moss, Jennifer L

2015-07-01

Adolescents exposed to domestic violence are at increased risk of dating abuse, yet no evaluated dating abuse prevention programs have been designed specifically for this high-risk population. This article describes the process of adapting Families for Safe Dates (FSD), an evidenced-based universal dating abuse prevention program, to this high-risk population, including conducting 12 focus groups and 107 interviews with the target audience. FSD includes six booklets of dating abuse prevention information, and activities for parents and adolescents to do together at home. We adapted FSD for mothers who were victims of domestic violence, but who no longer lived with the abuser, to do with their adolescents who had been exposed to the violence. Through the adaptation process, we learned that families liked the program structure and valued being offered the program and that some of our initial assumptions about this population were incorrect. We identified practices and beliefs of mother victims and attributes of these adolescents that might increase their risk of dating abuse that we had not previously considered. In addition, we learned that some of the content of the original program generated negative family interactions for some. The findings demonstrate the utility of using a careful process to adapt evidence-based interventions (EBIs) to cultural sub-groups, particularly the importance of obtaining feedback on the program from the target audience. Others can follow this process to adapt EBIs to groups other than the ones for which the original EBI was designed. © The Author(s) 2014.

A group randomized controlled trial integrating obesity prevention and control for postpartum adolescents in a home visiting program.

Science.gov (United States)

Haire-Joshu, Debra L; Schwarz, Cynthia D; Peskoe, Sarah B; Budd, Elizabeth L; Brownson, Ross C; Joshu, Corinne E

2015-06-26

Adolescence represents a critical period for the development of overweight that tracks into adulthood. This risk is significantly heightened for adolescents that become pregnant, many of whom experience postpartum weight retention. The aim of this study was to evaluate Balance Adolescent Lifestyle Activities and Nutrition Choices for Energy (BALANCE), a multicomponent obesity prevention intervention targeting postpartum adolescents participating in a national home visiting child development-parent education program. A group randomized, nested cohort design was used with 1325 adolescents, 694 intervention and 490 control, (mean age = 17.8 years, 52 % underrepresented minorities) located across 30 states. Participatory methods were used to integrate lifestyle behavior change strategies within standard parent education practice. Content targeted replacement of high-risk obesogenic patterns (e.g. sweetened drink and high fat snack consumption, sedentary activity) with positive behaviors (e.g. water intake, fruit and vegetables, increased walking). Parent educators delivered BALANCE through home visits, school based classroom-group meetings, and website activities. Control adolescents received standard child development information. Phase I included baseline to posttest (12 months); Phase II included baseline to follow-up (24 months). When compared to the control group, BALANCE adolescents who were ≥12 weeks postpartum were 89 % more likely (p = 0.02) to maintain a normal BMI or improve an overweight/obese BMI by 12 months; this change was not sustained at 24 months. When compared to the control group, BALANCE adolescents significantly improved fruit and vegetable intake (p = .03). In stratified analyses, water intake improved among younger BALANCE teens (p = .001) and overweight/obese BALANCE teens (p = .05) when compared to control counterparts. There were no significant differences between groups in sweetened drink and snack consumption

The main reasons of conflicts between adolescents in the multicultural class and their prevention

Directory of Open Access Journals (Sweden)

Khuhlaeva O.V.

2017-10-01

Full Text Available The conflict interaction in the adolescent environment, mainly in the context of intercultural interaction, is considered in the article on the basis of theoretical analysis. The relationship between conflict in adolescence and the overcoming of adolescent crisis is described, as well as the conflict was correlated with other age characteristics. A special emphasis is placed on intergroup conflicts. An additional specificity of conflicts in school classes with mixed cultural composition is discussed. An analysis of the specifics of the conflict interaction in connection with the measurement of cultures by G. Hofstede was carried out (individualism-collectivism, power distance, masculinity-femininity and avoidance of uncertainty. The conclusion about the greater urgency of potential contradictions is being made if there are teenagers belonging to widely differing cultures in the school class. The role of laughter culture as manifestations of antipodes in game form for the prevention and correction of conflicts in a adolescent multicultural environment is shown.

Construction and validation of educational materials for the prevention of metabolic syndrome in adolescents.

Science.gov (United States)

Moura, Ionara Holanda de; Silva, Antônia Fabiana Rodrigues da; Rocha, Aparecida do Espírito Santo de Holanda; Lima, Luisa Helena de Oliveira; Moreira, Thereza Maria Magalhães; Silva, Ana Roberta Vilarouca da

2017-10-05

To develop and validate an educational technology focused on prevention of metabolic syndrome among adolescents. This was methodological research. Using an integrative review, the available publications on the subject were analyzed. Then, this knowledge was used to describe the theoretical content and, with the help of a graphic designer, the art and layout of the pages were developed. In the third phase, the booklet was evaluated and validated by 21 specialists and 39 adolescents. Data collection included three different questionnaires, according to the focus of evaluation of each group of participants, analyzed for reliability (Cronbach's Alpha) and agreement by Infraclass Correlation Coefficient. The mean score attributed by technical content experts was 91.7%, and the content validity index, measured by experts responses, was 0.98, showing high reliability and agreement. In addition, the level of agreement of the positive responses given by adolescents was 88.4%. the educational booklet has proved to be a valid and reliable tool to be used for promoting adolescent health.

Efficacy of Adolescent Suicide Prevention E-Learning Modules for Gatekeepers : A Randomized Controlled Trial

NARCIS (Netherlands)

Ghoncheh, Rezvan; Gould, Madelyn S; Twisk, Jos Wr; Kerkhof, Ad Jfm; Koot, Hans M

2016-01-01

BACKGROUND: Face-to-face gatekeeper training can be an effective strategy in the enhancement of gatekeepers' knowledge and self-efficacy in adolescent suicide prevention. However, barriers related to access (eg, time, resources) may hamper participation in face-to-face training sessions. The

Systematic review of mental health and well-being outcomes following community-based obesity prevention interventions among adolescents.

Science.gov (United States)

Hoare, Erin; Fuller-Tyszkiewicz, Matthew; Skouteris, Helen; Millar, Lynne; Nichols, Melanie; Allender, Steven

2015-01-05

This paper aimed to systematically evaluate the mental health and well-being outcomes observed in previous community-based obesity prevention interventions in adolescent populations. Systematic review of literature from database inception to October 2014. Articles were sourced from CINAHL, Global Health, Health Source: Nursing and Academic Edition, MEDLINE, PsycARTICLES and PsycINFO, all of which were accessed through EBSCOhost. The Cochrane Database was also searched to identify all eligible articles. PRISMA guidelines were followed and search terms and search strategy ensured all possible studies were identified for review. Intervention studies were eligible for inclusion if they were: focused on overweight or obesity prevention, community-based, targeted adolescents (aged 10-19 years), reported a mental health or well-being measure, and included a comparison or control group. Studies that focused on specific adolescent groups or were treatment interventions were excluded from review. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines. Primary outcomes were measures of mental health and well-being, including diagnostic and symptomatic measures. Secondary outcomes included adiposity or weight-related measures. Seven studies met the inclusion criteria; one reported anxiety/depressive outcomes, two reported on self-perception well-being measures such as self-esteem and self-efficacy, and four studies reported outcomes of quality of life. Positive mental health outcomes demonstrated that following obesity prevention, interventions included a decrease in anxiety and improved health-related quality of life. Quality of evidence was graded as very low. Although positive outcomes for mental health and well-being do exist, controlled evaluations of community-based obesity prevention interventions have not often included mental health measures (n=7). It is recommended that future interventions

Systematic review of mental health and well-being outcomes following community-based obesity prevention interventions among adolescents

Science.gov (United States)

Hoare, Erin; Fuller-Tyszkiewicz, Matthew; Skouteris, Helen; Millar, Lynne; Nichols, Melanie; Allender, Steven

2015-01-01

Objectives This paper aimed to systematically evaluate the mental health and well-being outcomes observed in previous community-based obesity prevention interventions in adolescent populations. Setting Systematic review of literature from database inception to October 2014. Articles were sourced from CINAHL, Global Health, Health Source: Nursing and Academic Edition, MEDLINE, PsycARTICLES and PsycINFO, all of which were accessed through EBSCOhost. The Cochrane Database was also searched to identify all eligible articles. PRISMA guidelines were followed and search terms and search strategy ensured all possible studies were identified for review. Participants Intervention studies were eligible for inclusion if they were: focused on overweight or obesity prevention, community-based, targeted adolescents (aged 10–19 years), reported a mental health or well-being measure, and included a comparison or control group. Studies that focused on specific adolescent groups or were treatment interventions were excluded from review. Quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) guidelines. Primary and secondary outcome measures Primary outcomes were measures of mental health and well-being, including diagnostic and symptomatic measures. Secondary outcomes included adiposity or weight-related measures. Results Seven studies met the inclusion criteria; one reported anxiety/depressive outcomes, two reported on self-perception well-being measures such as self-esteem and self-efficacy, and four studies reported outcomes of quality of life. Positive mental health outcomes demonstrated that following obesity prevention, interventions included a decrease in anxiety and improved health-related quality of life. Quality of evidence was graded as very low. Conclusions Although positive outcomes for mental health and well-being do exist, controlled evaluations of community-based obesity prevention interventions have

The role of 1-h physical activity every day in preventing obesity in adolescents in Shandong, China.

Science.gov (United States)

Ying-Xiu, Zhang; Jing-Yang, Zhou; Jin-Shan, Zhao; Zun-Hua, Chu

2013-03-01

Several studies have reported that physical inactivity and sedentary lifestyle are associated with being overweight and obese in children and adults. A new policy of 1-h physical activity (PA) every day was released by the Chinese government. The present study examined the role of 1-h PA every day in preventing obesity in adolescents in Shandong, China. A total of 29,030 students (14,578 boys and 14,452 girls) aged 10-18 years participated in this study. Height, weight, waist circumference (WC), and skinfold thickness (SFT) of all subjects were measured; body mass index (BMI) of adolescents was calculated from their height and weight, and the prevalence of overweight and obesity was obtained according to the International Obesity Task Force cutoffs. All subjects were divided into two groups. Group 1 had a PA of more than 1 h/day while group 2 had less than 1 h/day. Comparisons of BMI, WC, SFT, and prevalences of overweight and obesity between the two groups were made. The overall percentages of students in group 1 were 34.29 % in boys and 30.15 % in girls. The prevalences of overweight and obesity for both boys and girls were all significantly lower in group 1 than in group 2 in all age categories. In conclusion, 1-h PA every day has a beneficial effect in preventing obesity in adolescents in Shandong, China. These observations highlight the importance of PA in the prevention of overweight and obesity in adolescents.

Measurement of the internal magnetic fluctuation by the transport of runaways on J-TEXT

Energy Technology Data Exchange (ETDEWEB)

Chen, Z. Y., E-mail: zychen@hust.edu.cn; Huang, D. W.; Tong, R. H.; Yan, W.; Wei, Y. N.; Ma, T. K.; Jiang, Z. H.; Zhang, X. Q.; Chen, Z. P.; Yang, Z. J.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2016-11-15

The measurement of internal magnetic fluctuation is important for the study of transport in tokamak plasmas. The runaway electron transport induced by the sawtooth crash can be used to obtain the internal magnetic fluctuation. Inversed sawtooth-like activities on hard x-ray (HXR) fluxes following sawtooth activities were observed after the application of electrode biasing on J-TEXT tokamak. The runaway diffusion coefficient D{sub r} is deduced to be about 30 m{sup 2}/s according to the time delay of HXR flux peaks to the sawtooth crashes. The averaged value of normalized magnetic fluctuation in the discharges with electrode biasing was increased to the order of 1 × 10{sup −4}.

Prevention of Problem Behaviours among Adolescents: The Impact of the Communities That Care Strategy in the Netherlands (2008-2011)

Science.gov (United States)

Jonkman, Harrie; Aussems, Claire; Steketee, Majone; Boutellier, Hans; Cuijpers, Pim

2015-01-01

This study examines whether the Communities That Care (CTC) prevention system influences targeted risk and protective factors and the subsequent development of problem behaviour among adolescents (12-18 years) in the Netherlands. In this quasi-experimental study of ten communities (five experimental, five control), adolescent outcomes were…

The Usability and Acceptability of an Adolescent mHealth HIV/STI and Drug Abuse Preventive Intervention in Primary Care.

Science.gov (United States)

Cordova, David; Alers-Rojas, Francheska; Lua, Frania Mendoza; Bauermeister, Jose; Nurenberg, Rachel; Ovadje, Lauretta; Fessler, Kathryn; Delva, Jorge; Salas-Wright, Christopher P; Council, Youth Leadership

2018-01-01

Human Immunodeficiency Virus (HIV)/sexually transmitted infection (STI) risk behaviors among adolescents remain significant public health concerns. Shifts in policy and advances in technology provide opportunities for researchers and clinicians to deliver and evaluate mobile-health (mHealth) prevention programs in primary care, however, research is limited. This study assessed the usability and acceptability of Storytelling 4 Empowerment-a mHealth HIV/STI and drug abuse preventive intervention app-among adolescents in primary care. Informed by principles of community-based participatory research, we recruited a purposive sample of 30 adolescents from a youth-centered community health care clinic in Southeast Michigan. The study sample is primarily African American and female. Adolescents who participated in the Storytelling 4 Empowerment intervention assessed its usability and acceptability, and self-reported their HIV/STI risk behaviors. We used a multiple-methods approach. Adolescents reported high acceptability of the content, process, and format of Storytelling 4 Empowerment, as evidenced by qualitative data and mean scores from the Session Evaluation Form for the HIV/STI and Alcohol/Drug content, overall Storytelling 4 Empowerment intervention, and Client Satisfaction Questionnaire-8. Findings indicate that Storytelling 4 Empowerment is acceptable among adolescents in primary care. A next step is to examine the effect of Storytelling 4 Empowerment on adolescent sexual risk and drug use behaviors and HIV/STI testing.

Increased insolation threshold for runaway greenhouse processes on Earth-like planets.

Science.gov (United States)

Leconte, Jérémy; Forget, Francois; Charnay, Benjamin; Wordsworth, Robin; Pottier, Alizée

2013-12-12

The increase in solar luminosity over geological timescales should warm the Earth's climate, increasing water evaporation, which will in turn enhance the atmospheric greenhouse effect. Above a certain critical insolation, this destabilizing greenhouse feedback can 'run away' until the oceans have completely evaporated. Through increases in stratospheric humidity, warming may also cause evaporative loss of the oceans to space before the runaway greenhouse state occurs. The critical insolation thresholds for these processes, however, remain uncertain because they have so far been evaluated using one-dimensional models that cannot account for the dynamical and cloud feedback effects that are key stabilizing features of the Earth's climate. Here we use a three-dimensional global climate model to show that the insolation threshold for the runaway greenhouse state to occur is about 375 W m(-2), which is significantly higher than previously thought. Our model is specifically developed to quantify the climate response of Earth-like planets to increased insolation in hot and extremely moist atmospheres. In contrast with previous studies, we find that clouds have a destabilizing feedback effect on the long-term warming. However, subsident, unsaturated regions created by the Hadley circulation have a stabilizing effect that is strong enough to shift the runaway greenhouse limit to higher values of insolation than are inferred from one-dimensional models. Furthermore, because of wavelength-dependent radiative effects, the stratosphere remains sufficiently cold and dry to hamper the escape of atmospheric water, even at large fluxes. This has strong implications for the possibility of liquid water existing on Venus early in its history, and extends the size of the habitable zone around other stars.

Preventing Drug Abuse Among Hispanic Adolescents: Developing a Responsive Intervention Approach.

Science.gov (United States)

Schinke, Steven P; Schwinn, Traci M; Hursh, Hilary A

2015-10-01

Intervention research is essential to help Hispanic American adolescents avoid drug use. This article describes an intervention research program aimed at preventing drug use among these youths. Grounded in salient epidemiological data, the program is informed by bicultural competence, social learning, and motivational interviewing theories. The program, called Vamos, is aimed at the risk and protective factors as well as the cultural prerogatives that demark the adolescent years of Hispanic American youths. Innovative in its approach, the program is delivered through a smartphone application (app). By interacting with engaging content presented via the app, youths can acquire the cognitive-behavioral skills necessary to avoid risky situations, urges, and pressures associated with early drug use. The intervention development process is presented in detail, and an evaluation plan to determine the program's efficacy is outlined. Lessons for practice and intervention programming are discussed.

Magnetic field effects on runaway electron energy deposition in plasma facing materials and components

International Nuclear Information System (INIS)

Niemer, K.A.; Gilligan, J.G.

1992-01-01

This paper reports magnetic field effects on runaway electron energy deposition in plasma facing materials and components is investigated using the Integrated TIGER Series. The Integrated TIGER Series is a set of time-independent coupled electron/photon Monte Carlo transport codes which perform photon and electron transport, with or without macroscopic electric and magnetic fields. A three-dimensional computational model of 100 MeV electrons incident on a graphite block was used to simulate runawayelectrons striking a plasma facing component at the edge of a tokamak. Results show that more energy from runaway electrons will be deposited in a material that is in the presence of a magnetic field than in a material that is in the presence of no field. For low angle incident runaway electrons in a strong magnetic field, the majority of the increased energy deposition is near the material surface with a higher energy density. Electrons which would have been reflected with no field, orbit the magnetic field lines and are redeposited in the material surface, resulting in a substantial increase in surface energy deposition. Based on previous studies, the higher energy deposition and energy density will result in higher temperatures which are expected to cause more damage to a plasma facing component

Malaria: Knowledge and prevention practices among school adolescents in a coastal community in Calabar, Nigeria

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Ndifreke E. Udonwa

2010-04-01

Objectives: To determine the malaria prevention practices of school adolescents in the coastal community of Calabar, Nigeria. Method: This was a cross-sectional survey involving secondary schools in southern Calabar. Four hundred adolescents were randomly selected from the 4565 learners in 5 out of 17 secondary schools in southern Calabar, Cross River State, Nigeria. A self-administered, semi-structured questionnaire was administered to the respondents. Results: Most respondents (77.5% were aware that the vector transmits the malaria parasite through biting. Fewer respondents would prevent malaria attacks by clearing the vegetation in the peri-domestic environment (13.5%, filling up potholes (16.9%, opening up drainage (11%, using insecticide-treated nets (25.7% or using antimalarial drugs (11.2%. Less than one-tenth (8% would use various other methods such as not accepting unscreened blood, while only 11% obtained the information from their teachers. Conclusion: The study identified knowledge gaps among school children. There is a need to empower teachers with information about the cause of malaria and prevention strategies.

Adolescent pregnancy. Teen perspectives on prevention.

Science.gov (United States)

Aquilino, M L; Bragadottir, H

2000-01-01

To elicit the views of teens concerning effective strategies to prevent pregnancy. Qualitative methods and a focus group approach were used. The sample consisted of male and female adolescents, 14 to 19 years of age, in grades 9 to 12, who volunteered to participate in the study. Seven groups of teens met with the investigator twice over 2 consecutive weeks. Instruments included a Screening Questionnaire and Focus Group Discussion Guidelines. Teens were concerned about teen pregnancy, and supported a comprehensive approach to sex education beginning in the early elementary grades, with age and developmentally appropriate content and reinforcement from late grade school through high school. Generally, teens thought that teaching abstinence in grade school followed by contraception education in junior high and high school was a realistic strategy for pregnancy prevention. They wanted to discuss sexual feelings as well as the mechanical aspects of sex. Finally, they did not want to be told not to have sex, but rather wanted to be guided in their own decision making. Teens wanted parents and other adults to be involved in helping them understand sexuality and make decisions about sexual behavior. Nurses who work with families need to understand why teens are becoming pregnant, provide opportunities for teens to discuss sexual behavior, and educate parents on sexual development and parent-child communication. Nurses also need to let parents and teens know that they are a resource for information, guidance, and health services related to sexual development and behavior.