696 research outputs found

    Magnetic field generated resistivity maximum in graphite

    Get PDF
    In zero magnetic field, B, the electrical resistivity, rho(O,T) of highly oriented pyrolytic (polycrystalline) graphite drops smoothly with decreasing T, becoming constant below 4 K. However, in a fixed applied magnetic field B, the resistivity rho(B,T) goes through a maximum as a function of T, with larger maximum for larger B. The temperature of the maximum increases with B, but saturates to a constant value near 25 K (exact T depends on sample) at high B. In single crystal graphite a maximum in rho(B,T) as a function of T is also present, but has the effects of Landau level quantization superimposed. Several possible explanations for the rho(B,T) maximum are proposed, but a complete explanation awaits detailed calculations involving the energy band structure of graphite, and the particular scattering mechanisms involved

    Effects of Livestock Grazing Management on Grassland Bird Abundance in the Northern Mixed-Grass Prairie

    Get PDF
    Grassland bird populations have been declining throughout a majority of their range in the United States and Canada over the past 40 years, and currently have the most accelerated declines of any guild of terrestrial birds in this region. Rangelands used for domestic cattle grazing are important for maintaining large tracts of native grassland that may otherwise be converted to agricultural use or other human development. In addition, grassland birds respond well to livestock grazing systems that increase habitat heterogeneity by mimicking historic grassland disturbance, such as fire and bison grazing. Montana Department of Fish, Wildlife, and Parks (FWP) implements a rest-rotation grazing system within conservation easements to increase structural heterogeneity of grassland vegetation on the landscape. However, the rest-rotation grazing system administered by Montana FWP was developed for more arid, bunchgrass-dominated rangelands and has not been evaluated as a management tool for creating structurally diverse wildlife habitat in the northern mixed-grass prairie. This study examines the effect of a rest-rotation grazing system on breeding season habitat selection and abundance of four native grassland songbird species, Baird’s sparrow (Ammodramus bairdii), grasshopper sparrow (Ammodramus savannarum), vesper sparrow (Pooecetes gramineus), and western meadowlark (Sturnella neglecta), relative to traditional season-long or rotational grazing systems on a Montana FWP conservation easement in eastern Montana. Our objectives for the study are: 1) evaluate how abundance and spaceuse of four focal grassland bird species are affected by grazing treatment; 2) estimate the importance of habitat and vegetation characteristics for focal species within pasture treatments; 3) offer management recommendations to agencies and private landowners for improving grassland bird abundance and habitat quality

    Flipped gaming-testing three simulation games

    Full text link
    © 2018 IEEE. At the Inland Norway University of Applied Sciences 'flipped gaming' has been tested with two student groups (in 2017). This paper will present a newer version of the 'flipping' and also how a total of eight groups utilized tree different types of simulators to play the scenarios. The scenarios were developed by the student themselves as this was their mandatory assignment. The mandatory assignment was handed out in January. The assignment was about making a playable script for an incident, in addition to conduct the planning, execution and evaluation of a complete exercise in crisis management. They were given feedback once before the workshop where they presented and played the script. The tools that were used was Rayvn (https://rayvn.global/), Microsoft HoloLens (https://www.microsoft.com/nb-no/hololens) and a simulator based on a platform from Bohemia Interactive Solutions (https://bisimulations.com/)-the same platform as Virtual Battle Space 3 uses. Rayvn is an incident management tool, mainly for communication. The written messages can then be logged and stored for later reflections. Microsoft HoloLens is a tool for 3D vision, a tool that can show environments in 3D and allow the player to carry out operations using movements that are recorded and executed. This was a prototype. The game based simulator is computer based. The different views are 2D maps and 3D environments. The players use the keyboard and mouse to move the vehicles and avatars around. This in a 'disaster town', called 'Lyngvik', a very poor planned city centre with a large accident/crisis potential. The study is based on the previous study of the learning outcome from assignment that is based on student input. The mandatory assignment was to develop a playable scenario and they could choose in which of the three different simulation tools they were to play their scenario. Two by two, the groups are to play each other's scenario. They have received some supervision and the lecturers have remarked on that the students may lack insight in what a 'playable scenario' require. One of the groups operates as the exercise management staff(the ones that makes the incidents happen and 'play out') and the other group is the ones who man the different roles in handling the scenario e.g.,-different call out services. This group is also calledmain training audience (MTA). The students are in their 6th and last semester in their Bachelor in Crisis Management. The students have been subjected to diverse teaching methods, but this is the first time they have a simulation tool to work with in order to enhance their learning outcome. The preliminary reports from the reflections after the simulating are very positive. The students report on a learning outcome, both from making the scenarios and from simulating. There is also a final report to be written where the students are to reflect on their learning outcome from the simulation and the work on the assignment. The paper shows the results from the whole undertaking and presents further details from the different phases. We also present the theoretical backdrop and the methodological reasoning behind the data collection and analysis

    Using games for teaching crisis communication in higher education and training

    Full text link
    © 2016 IEEE. Terror actions and catastrophes are frequently described in media. As more and more countries experience terror actions and natural disasters, there has been a greater focus on learning how to handle and to manage them. In Norway on the 22nd of July 2011, Anders Behring Breivik placed a bomb in a car that exploded near the Governmental Offices killing 8 persons. He went on to an island where there was a political camp for youths killing another 67. The rescue operations unveiled an unprepared task force. The Gjrv-report provide a massive critique towards the call out services [1]. This kicked off a major work on updating safety routines in all municipalities. The municipalities are now obliged to have a plan for crisis preparedness [2]. This again triggered the need for education within the area of crisis preparedness, crisis training and crisis management. Hedmark University of Applied Science now offers different study programs, including a BA within these areas. It is, however, very expensive to train realistically and the need for different approaches regarding training has been discussed. One of the solutions that the University is currently working on, is the use of games. Game based learning, also called 'serious games', has become an academic genre and using games for learning and training has proven fruitful [3-12]. In the military, games have been used for simulation purposes [13] and spin offs from these have also reached a commercial market [14, 15]. Using games in education opens up a range of opportunities. One of them is within the area of Crisis Communication. Crisis Communication as a curriculum is about how to approach the area of crisis communication, understanding the key concepts and develop skills within the curriculum. Games that support communication between the gamers can for instance contribute towards a greater understanding of communication in a crisis situation. What is needed to communicate and how messages are received, in order to support handling a crisis, are amongst the concrete learning objectives one can attribute towards this type of training. To use games to support the hands on training can thus provide the learners with valuable know how, and support their learning outcome. The learning from this will be beneficial to the organizations they work in as they will have an experience that will aid them in the work on planning for and preparing for crisis in their own organizations

    Student input-A case of an extended flipped classroom

    Get PDF
    © 2017 IEEE. The idea from Socrates about the knowledge being a part of the students' knowledge base or ability of combining accessible knowledge forms the backdrop for how the most recent course in Knowledge Management (spring of 2017) was conducted. The course is 7,5 ECTS and the students are primarily adults in a worklife. The course is net and seminar based, with three seminars per semester. During the seminars the concept of Flipped Classroom is used. This means that the students are provided with a recorded lecture in beforehand and only highlights are presented. The rest of the time during the seminar is used to activate the students through tasks and problem solving. However, the tasks are not predefined and prefabricated. The way this course is structured, the students themselves are giving the input to the tasks and assignments. This is based on the idea that the students themselves, coming from a worklife where knowledge management is a part of their every day worklife, should reflect upon their own practice. Also, it is important to share knowledge and by utilizing each students own experiences it is possible to enrich the 'database' of cases or tasks for the students to solve and work with in order to incorporate the new theory from the course curriculum. Basing the problem solving on student input provide the lecturer AND the students with a richer knowledge base and case portfolio. This does, however, require some effort from the lecturers side. The input from the students are generally key words and fragments. The session is facilitated by the lecturer, encouraging the students to bring forward own experiences or situations they would like resolved, either real or fiction. The key words and fragments are discussed amongst the students and the lecturer makes notes on a blackboard or on a digital canvas (MS PowerPoint or similar). The students are given a break and the lecturer collects the key words and synthesizes this into a case. Upon the return of the students, they solve the cases in groups and discuss possible solutions and what theory that apply to the different aspects of the case. Then a plenary session is facilitated where a suggested solution is developed. During a one-day seminar three to four cases are developed as a 'joint venture' amongst the students and the lecturer. The feedback from the students is very positive. They claim that this way of working strongly contributes to an enhanced learning outcome. Some students also report on utilizing knowledge acquired at these seminars back at their workplace. These are some results from the survey and interviews. This research will be presented in detail in the paper. We will also elaborate on how this way of flipping the classroom can be utilized in different courses and areas

    Crossover effects in a discrete deposition model with Kardar-Parisi-Zhang scaling

    Full text link
    We simulated a growth model in 1+1 dimensions in which particles are aggregated according to the rules of ballistic deposition with probability p or according to the rules of random deposition with surface relaxation (Family model) with probability 1-p. For any p>0, this system is in the Kardar-Parisi-Zhang (KPZ) universality class, but it presents a slow crossover from the Edwards-Wilkinson class (EW) for small p. From the scaling of the growth velocity, the parameter p is connected to the coefficient of the nonlinear term of the KPZ equation, lambda, giving lambda ~ p^gamma, with gamma = 2.1 +- 0.2. Our numerical results confirm the interface width scaling in the growth regime as W ~ lambda^beta t^beta, and the scaling of the saturation time as tau ~ lambda^(-1) L^z, with the expected exponents beta =1/3 and z=3/2 and strong corrections to scaling for small lambda. This picture is consistent with a crossover time from EW to KPZ growth in the form t_c ~ lambda^(-4) ~ p^(-8), in agreement with scaling theories and renormalization group analysis. Some consequences of the slow crossover in this problem are discussed and may help investigations of more complex models.Comment: 16 pages, 7 figures; to appear in Phys. Rev.

    Changes in substance use during outpatient treatment for substance use disorders: a prospective Norwegian cohort study from 2016 to 2020

    Get PDF
    Background Continuous use of amphetamines, alcohol, benzodiazepines, cannabis, cocaine, or opioids contributes to health impairments, increased morbidity, and overdose deaths among patients with substance use disorders (SUDs). This study evaluates the impact of inpatient detoxification, injecting substance use, age, and gender on substance use over time among patients undergoing outpatient SUD treatment. Methods We used data from a cohort of SUD patients in Norway obtained from health assessments of self-reported substance use and sociodemographic and clinical factors. A total of 881 substance use measurements, including substances and frequency of use, were assessed for 708 SUD patients in 2016–2020. Of those, 171 patients provided two or more substance use measurements. The total substance use was calculated, creating a substance use severity index (SUSI), ranging from zero (no use) to one (daily use of all substances). We defined baseline as the first substance use measurement when the measurements were listed chronologically. Time was defined as years from baseline. We used a linear mixed model to analyze the SUSI at baseline and over time, and its associations with inpatient detoxification, injecting substance use, gender, and age, presented with coefficients and 95% confidence intervals (CI). Results No longitudinal changes in the SUSI were found compared with baseline (change in SUSI (cSUSI): 0.04, 95% CI: − 0.05;0.13, p = 0.397). Likewise, “inpatient detoxification” was not associated with changes in the SUSI compared with “no inpatient detoxification” (cSUSI: 0.00, 95% CI: − 0.04;0.04, p = 0.952). However, injecting substances were associated with a higher SUSI than not injecting substances at baseline (difference in SUSI: 0.19, 95% CI: 0.16;0.21, p = < 0.001), and starting to inject substances was associated with increasing SUSI over time compared with not starting to inject substances (cSUSI: 0.11, 95% CI: 0.07;0.15, p = < 0.001). Gender was not significantly associated with changes in the SUSI (cSUSI: − 0.04, 95% CI: − 0.07;0.00, p = 0.052), while patients over 60 years of age had a lower SUSI than those under the age of 30 at baseline (difference in SUSI: − 0.08, 95% CI: − 0.14;− 0.01, p = 0.018), with no change over time (cSUSI: − 0.05, 95% CI: − 0.16;0.05, p = 0.297). Conclusion The present study demonstrates that inpatient detoxification was not associated with substance use changes over time for patients undergoing outpatient SUD treatment. Otherwise, injecting substance use was a particular risk factor for a high level of substance use. Future research needs to evaluate the impact of other treatment approaches on substance use, ideally in randomized controlled trials.publishedVersio

    Vitamin D status and associations with substance use patterns among people with severe substance use disorders in Western Norway

    Get PDF
    Chronic and harmful substance use is associated with a cluster of harms to health, including micronutrient deficiencies. Maintaining adequate levels of vitamin D is important for musculoskeletal and other aspects of health. In this prospective longitudinal cohort study, 666 participants drawn from outpatient opioid agonist therapy (OAT) clinics and community care clinics for substance use disorder in Western Norway were assessed annually for determination of serum 25-hydroxyvitamin D [s-25(OH)D] levels. Fifty-seven percent were deficient at baseline (s-25(OH)D < 50 nmol/l), and 19% were severely deficient (s-25(OH)D < 25 nmol/l). Among those deficient/severely deficient at baseline, 70% remained deficient/severely deficient at the last measurement (mean duration 714 days). Substance use patterns and dosage of opioids for OAT were not associated with vitamin D levels. One exception was found for cannabis, where consumption on a minimum weekly basis was associated with lower levels at baseline (mean difference: −5.2 nmol/l, 95% confidence interval [CI]: −9.1, − 1.3), but without clear time trends (mean change per year: 1.4 nmol/l, CI: − 0.86, 3.7). The high prevalence of sustained vitamin D deficiency in this cohort highlights the need for targeted monitoring and supplementation for this and similar at-risk populations.publishedVersio

    Growth model with restricted surface relaxation

    Full text link
    We simulate a growth model with restricted surface relaxation process in d=1 and d=2, where d is the dimensionality of a flat substrate. In this model, each particle can relax on the surface to a local minimum, as the Edwards-Wilkinson linear model, but only within a distance s. If the local minimum is out from this distance, the particle evaporates through a refuse mechanism similar to the Kim-Kosterlitz nonlinear model. In d=1, the growth exponent beta, measured from the temporal behavior of roughness, indicates that in the coarse-grained limit, the linear term of the Kardar-Parisi-Zhang equation dominates in short times (low-roughness) and, in asymptotic times, the nonlinear term prevails. The crossover between linear and nonlinear behaviors occurs in a characteristic time t_c which only depends on the magnitude of the parameter s, related to the nonlinear term. In d=2, we find indications of a similar crossover, that is, logarithmic temporal behavior of roughness in short times and power law behavior in asymptotic times

    Nucleon Edm from Atomic Systems and Constraints on Supersymmetry Parameters

    Full text link
    The nucleon EDM is shown to be directly related to the EDM of atomic systems. From the observed EDM values of the atomic Hg system, the neutron EDM can be extracted, which gives a very stringent constraint on the supersymmetry parameters. It is also shown that the measurement of Nitrogen and Thallium atomic systems should provide important information on the flavor dependence of the quark EDM. We perform numerical analyses on the EDM of neutron, proton and electron in the minimal supersymmetric standard model with CP-violating phases. We demonstrate that the new limit on the neutron EDM extracted from atomic systems excludes a wide parameter region of supersymmetry breaking masses above 1 TeV, while the old limit excludes only a small mass region below 1 TeV.Comment: 10 pages, 7 figure file
    corecore