ENERGETIC PARTICLE DIFFUSION IN CRITICALLY BALANCED TURBULENCE

Observations and modeling suggest that the fluctuations in magnetized plasmas exhibit scale-dependent anisotropy, with more energy in the fluctuations perpendicular to the mean magnetic field than in the parallel fluctuations and the anisotropy increasing at smaller scales. The scale dependence of the anisotropy has not been studied in full-orbit simulations of particle transport in turbulent plasmas so far. In this paper, we construct a model of critically balanced turbulence, as suggested by Goldreich & Sridhar, and calculate energetic particle spatial diffusion coefficients using full-orbit simulations. The model uses an enveloped turbulence approach, where each two-dimensional wave mode with wavenumber k ⊥ is packed into envelopes of length L following the critical balance condition, Lk –2/3 ⊥, with the wave mode parameters changing between envelopes. Using full-orbit particle simulations, we find that both the parallel and perpendicular diffusion coefficients increase by a factor of two, compared to previous models with scale-independent anisotropy

Regular albuterol or nedocromil sodium — effects on airway subepithelial tenascin in asthma

AbstractBoth albuterol and nedocromil sodium have been recognized to possess certain anti-inflammatory properties. However, there are no data on the impact of these drugs on the pathophysiology of the bronchial extracellular matrix in asthma characterized by enhanced tenascin (Tn) expression, known to occur proportional to the severity of asthma. This paper reports data from a morphometric study on the effects of regular treatment with inhaled albuterol or nedocromil sodium on the extent of bronchial subepithelial deposition of Tn, collagen types III, IV, and VII and mucosal infiltration with macrophages.Thirty-two patients (14 women) with chronic asthma, aged 38·7 years (median) with a median forced expiratory volume in 1 sec (FEV1) of 74·4% predicted, were selected to undergo fibre-optic bronchoscopy with bronchial biopsies before and after 12 weeks of treatment with either inhaled albuterol 0·2 mg or nedocromil sodium 4 mg four times daily according to a double-blind protocol. Cryostat sections of the biopsy specimens were studied by indirect immunostaining techniques using monoclonal antibodies and computer-assisted quantitative image analysis.Albuterol treatment significantly reduced the median thickness of subepithelial Tn expression from 9·7 to 6·3 μm (P=0·023) and macrophage numbers in the epithelium (P=0·034), lamina propria (P=0·039) and entire mucosa (P=0·033), whereas nedocromil sodium had no effect. Expression of the collagen types was not affected by either treatment. There was no identifiable statistical difference between the two treatments for any of the outcome variables measured. Nevertheless, the results demonstrate that even a short-acting β2-agonist may exert anti-inflammatory potential sufficient to interfere with the basic mechanisms of asthma as shown by reduction of subepithelial Tn content and mucosal macrophage count

Drift induced perpendicular transport of solar energetic particles

Drifts are known to play a role in galactic cosmic ray transport within the heliosphere and are a standard component of cosmic ray propagation models. However, the current paradigm of solar energetic particle (SEP) propagation holds the effects of drifts to be negligible, and they are not accounted for in most current SEP modeling efforts. We present full-orbit test particle simulations of SEP propagation in a Parker spiral interplanetary magnetic field (IMF), which demonstrate that high-energy particle drifts cause significant asymmetric propagation perpendicular to the IMF. Thus in many cases the assumption of field-aligned propagation of SEPs may not be valid. We show that SEP drifts have dependencies on energy, heliographic latitude, and charge-to-mass ratio that are capable of transporting energetic particles perpendicular to the field over significant distances within interplanetary space, e.g., protons of initial energy 100 MeV propagate distances across the field on the order of 1 AU, over timescales typical of a gradual SEP event. Our results demonstrate the need for current models of SEP events to include the effects of particle drift. We show that the drift is considerably stronger for heavy ion SEPs due to their larger mass-to-charge ratio. This paradigm shift has important consequences for the modeling of SEP events and is crucial to the understanding and interpretation of in situ observations. © 2013. The American Astronomical Society. All rights reserved.

Alien Registration- Laitinen, Anna Sophie S. (Rockland, Knox County)

https://digitalmaine.com/alien_docs/16223/thumbnail.jp

Early propagation of energetic particles across the mean field in turbulent plasmas

Propagation of energetic particles across the mean field direction in turbulent magnetic fields is often described as spatial diffusion. Recently, it has been suggested that initially the particles prop- agate systematically along meandering field lines, and only later reach the time-asymptotic diffusive cross-field propagation. In this paper, we analyse cross-field propagation of 1–100 MeV protons in composite 2D-slab turbulence superposed on a constant background magnetic field, using full-orbit particle simulations, to study the non-diffusive phase of particle propagation with a wide range of turbulence parameters. We show that the early-time non-diffusive propagation of the particles is consistent with particle propagation along turbulently meandering field lines. This results in a wide cross-field extent of the particles already at the initial arrival of particles to a given distance along the mean field direction, unlike when using spatial diffusion particle transport models. The cross-field extent of the particle distribution remains constant for up to tens of hours in turbulence environ- ment consistent with the inner heliosphere during solar energetic particle events. Subsequently, the particles escape from their initial meandering field lines, and the particle propagation across the mean field reaches time-asymptotic diffusion. Our analysis shows that in order to understand so- lar energetic particle event origins, particle transport modelling must include non-diffusive particle propagation along meandering field lines. Key words: Sun: particle emission – diffusion – magnetic fields – turbulenc

Time dependence of Fe/O ratio within a 3D solar energetic particle propagation model including drift

Context. The intensity profiles of iron and oxygen in Solar Energetic Particle (SEP) events often display differences that result in a decreasing Fe/O ratio over time. The physical mechanisms behind this behaviour are not fully understood, but these observational signatures provide important tests of physical modelling efforts. Aims. In this paper we study the propagation of iron and oxygen SEP ions using a 3D model of propagation which includes the effect of guiding centre drift in a Parker spiral magnetic field. We derive time intensity profiles for a variety of observer locations and study the temporal evolution of the Fe/O ratio. Methods. We use a 3D full orbit test particle model which includes scattering. The configuration of the interplanetary magnetic field is a unipolar Parker spiral. Particles are released instantaneously from a compact region at two solar radii and allowed to propagate in 3D. Results. Both Fe and O experience significant transport across the magnetic field due to gradient and curvature drifts. We find that Fe ions drift more than O ions due to their larger mass-to-charge ratio, so that an observer that is not magnetically well connected to the source region will observe Fe arriving before O, for particles within the same range in energy per nucleon. As a result, for the majority of observer locations, the Fe/O ratio displays a decrease in time. Conclusions. We conclude that propagation effects associated with drifts produce a decay over time of the Fe/O ratio, qualitatively reproducing that observed in SEP event profiles

Effect of site of lactate infusion on regional lactate exchange in pigs

Background The rate of extra-hepatic lactate production and the route of influx of lactate to the liver may influence both hepatic and extra-hepatic lactate exchange. We assessed the dose-response of hepatic and extra-hepatic lactate exchange during portal and central venous lactate infusion. Methods Eighteen pigs randomly received either portal (n=5) or central venous (n=7) lactate infusion or saline (n=6). Sodium lactate was infused at 33, 66, 99, and 133 µmol kg−1 min−1 for 20 min each. Systemic and regional abdominal blood flows and plasma lactate were measured at 20 min intervals until 1 h post-infusion, and regional lactate exchange was calculated (area under lactate uptake-time curve). Results Total hepatic lactate uptake [median (95% confidence interval)] during the experimental protocol (140 min) was higher during portal [8198 (5487-12 798) µmol kg−1] than during central venous lactate infusion [4530 (3903-5514) µmol kg−1, P<0.05]. At a similar hepatic lactate delivery (∼400 µmol kg−1 min−1), hepatic lactate uptake [mean and standard deviation (sd)] was higher during portal [118 (sd 55) µmol kg−1 min−1] than during central venous lactate infusion [44 (12) µmol kg−1 min−1, P<0.05]. Time courses of arterial lactate concentrations and lactate uptake at other measured regions were similar in both groups. Conclusions Higher hepatic lactate uptake during portal compared with central venous lactate infusion at a similar total hepatic lactate influx underlines the role of portal vein lactate concentration in total hepatic lactate uptake capacity. Arterial lactate concentration does not depend on the site of lactate infusion. At higher arterial lactate concentrations, all regions participated in lactate uptak

Opinto-ohjaajien tulkintoja toisen asteen opiskelijoiden koulu-uupumuksesta, jaksamisen haasteista sekä tuen keinoista

Tiivistelmä. Opiskeluhyvinvoinnin haasteet, kuten koulu-uupumus, on nostettu esiin sekä tutkimuksessa että julkisessa keskustelussa ajankohtaisena aiheena. Vallitseva koronapandemia on lisännyt aihepiirin ajankohtaisuutta entisestään. Opinto-ohjaajat toimivat osana moniammatillista opiskelijahuoltoryhmää, ja ammatillisen koulutuksen ja lukiokoulutuksen erilaisten perustehtävien vuoksi myös niiden opinto-ohjauksen painopisteet ovat erilaisia. Tämän pro gradu -työn tavoitteena on selvittää, miten opinto-ohjaajat tulkitsevat toisen asteen opiskelijoiden koulu-uupumusta ja jaksamisen haasteita, millaisena he näkevät oman roolinsa opiskelijoiden tukena osana moniammatillista opiskelijahuoltoa sekä voidaanko opinto-ohjaajien tulkintojen pohjalta havaita opiskelijoiden koulu-uupumuksen ja jaksamisen haasteiden ilmenevän eri tavoin lukioiden ja ammatillisten oppilaitosten välillä. Tutkielman yleisorientaatio on hermeneuttinen, mikä korostaa tutkittavan ilmiön merkitysten syvällistä ymmärtämistä. Pyrkimyksenä ei ole kuitenkaan systemaattisesti tulkita tutkittavien käsityksiä, näkemyksiä, merkityksenantoja tai kokemuksia, vaan kuvata niitä sellaisenaan. Tutkimukseen osallistui kolme ammatillisen koulutuksen opinto-ohjaajaa ja kaksi lukion opinto-ohjaajaa. Teemahaastatteluilla kerätty aineisto on analysoitu temaattisen analyysin keinoin. Opinto-ohjaajien tulkinnoista muodostui neljä pääteemaa: 1) Jaksamisen haasteiden ja koulu-uupumuksen esiintyminen ja oireet, 2) Jaksamisen haasteiden ja koulu-uupumuksen taustatekijät, 3) Opinto-ohjaus, moniammatillinen yhteistyö ja opiskelijahuolto opiskelijan jaksamisen tukena sekä 4) Korona-ajan poikkeusolojen vaikutus opiskelijoiden jaksamiseen ja koulu-uupumukseen. Ammatillisen koulutuksen ja lukiokoulutuksen välisiä yhtäläisyyksiä ja eroja jaksamisen haasteiden ja koulu-uupumuksen suhteen on kuvattu kaikkien neljän teeman sisällä. Tuloksista ilmenee, että haastateltavat opinto-ohjaajat hahmottavat koulu-uupumuksen ja jaksamisen ongelmat laajana ja monitahoisena ilmiönä, ja niihin yhdistyy usein monenlaisia päällekkäisiä haasteita. Koulu-uupumuksen taustasyinä esille nousi erityisesti sosiaalisen tukiverkoston puute, yhteiskunnalliseen ilmapiiriin liittyvät tekijät, opiskelijan sopimattomuus opiskeluympäristöön sekä henkilökohtaisiin haasteisiin liittyvät tekijät. Ammatillisessa koulutuksessa merkittäväksi jaksamisen haasteita aiheuttavaksi tekijäksi nähtiin pelko työelämästä ja työelämässä oppimisesta, kun taas lukion opinto-ohjaajien tulkinnoissa korostuivat opinnoissa menestymiseen ja korkeakoulutukseen hakemiseen liittyvät paineet. Opinto-ohjaajan rooli nähtiin merkittävänä yhteisöllisen opiskeluhyvinvoinnin edistämisessä, jaksamisen haasteiden tunnistamisessa, opiskelijan eteenpäin ohjaamisessa, yksilöllisen opiskelupolun suunnittelussa sekä moniammatillisessa yhteistyössä. Kesällä 2020 tehdyissä haastatteluissa koronapandemiasta johtuvan etäopetuksen nähtiin sujuneen pääasiassa hyvin, mutta vaikuttavan opiskelijoiden jaksamiseen, koulu-uupumuksen puhkeamiseen sekä opintomenestykseltään eri tasoisten opiskelijoiden polarisoitumiseen.Interpretations of secondary school study counselors about school burnout, coping challenges, and means of support. Abstract. The challenges of study wellbeing such as school burnout has been raised as a topical issue in both the research and the public debate. The prevailing corona pandemic has further increased the timeliness of the topic. Study counselors act in their role as part of interprofessional student care, and their guidance priorities differ slightly due to the different basic tasks of vocational education and high school education. The aim of this master’s thesis is to find out how study counselors interpret secondary school students’ school burnout and challenges of coping in their studies, how they see their own roles supporting students as part of interprofessional student care and whether it can be detected differences between high schools’ and vocational schools’ student school burnout and challenges of coping based on the interpretations of study counselors interviewed. In this thesis the general orientation is based on hermeneutics, what is emphasizing an in-depth understanding of the meanings of the phenomenon under research. However, the aim is not to systematically interpret participants’ understanding, views, meanings, and experiences, but describe them as such. Three vocational school study counselors and two high school study counselors were participated in the study. Data was collected through a thematic interview and analyzed by thematic analysis. Four main themes were formed consisted of the interpretations of the study counselors: 1) Appearance and symptoms of challenges of coping and school burnout, 2) Background factors of challenges of coping and school burnout, 3) Study counselling, interprofessional cooperation and student care supporting student coping, and 4) The effect of exceptional circumstances due to corona pandemic on students’ coping and school burnout. The similarities and differences between vocational schools and high schools have been described within all four themes. The results show that the study counselors interviewed perceive the problems of school burnout and challenges of coping as a broad and complex phenomenon, often accompanied by diverse overlapping challenges. The lack of a social support, factors related to the societal atmosphere, the student’s unsuitability for the study environment, and factors related to personal challenges emerged as the root causes of school burnout. In vocational education, the fear of working life and periods of learning in working life was seen as a significant factor causing coping challenges, while the interpretations of high school study counselors emphasized the pressures related to individual success in studies and to apply for higher education. The study counselors were seen as significant persons in promoting community study well-being, identifying the challenges of coping, guiding the students forward, supporting the planning an individual study paths and working in interprofessional cooperation. In interviews conducted in the summer of 2020, distance teaching due to the corona pandemic was seen to have gone mainly well, but had an impact on student coping, the onset of school burnout, and the polarization of students at different levels of study success

Solar energetic particle access to distant longitudes through turbulent field-line meandering

Context. Current solar energetic particle (SEP) propagation models describe the effects of interplanetary plasma turbulence on SEPs as diffusion, using a Fokker-Planck (FP) equation. However, FP models cannot explain the observed fast access of SEPs across the average magnetic field to regions that are widely separated in longitude within the heliosphere without using unrealistically strong cross-field diffusion. Aims. We study whether the recently suggested early non-diffusive phase of SEP propagation can explain the wide SEP events with realistic particle transport parameters. Methods. We used a novel model that accounts for the SEP propagation along field lines that meander as a result of plasma turbulence. Such a non-diffusive propagation mode has been shown to dominate the SEP cross-field propagation early in the SEP event history. We compare the new model to the traditional approach, and to SEP observations. Results. Using the new model, we reproduce the observed longitudinal extent of SEP peak fluxes that are characterised by a Gaussian profile with σ = 30 − 50◦ , while current diffusion theory can only explain extents of 11◦ with realistic diffusion coefficients. Our model also reproduces the timing of SEP arrival at distant longitudes, which cannot be explained using the diffusion model. Conclusions. The early onset of SEPs over a wide range of longitudes can be understood as a result of the effects of magnetic fieldline random walk in the interplanetary medium and requires an SEP transport model that properly describes the non-diffusive early phase of SEP cross-field propagation