Significant enhancement of irreversibility field in clean-limit bulk MgB2

Low resistivity ("clean") MgB2 bulk samples annealed in Mg vapor show an increase in upper critical field Hc2(T) and irreversibility field Hirr(T) by a factor of 2 in both transport and magnetic measurements. The best sample displayed Hirr above 14 T at 4.2 K and 6 T at 20 K. These changes were accompanied by an increase of the 40 K resistivity from 1.0 to 18 microohm-cm and a lowering of the resistivity ratio from 15 to 3, while the critical temperature Tc decreased by only 1-2 K. These results point the way to make prepare MgB2 attractive for magnet applications.Comment: 3 pages, 4 figures, submitted to Applied Physics Letter

Cu_{2}O as nonmagnetic semiconductor for spin transport in crystalline oxide electronics

We probe spin transport in Cu_{2}O by measuring spin valve effect in La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co and La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/La_{0.7}Sr_{0.3}MnO_{3} epitaxial heterostructures. In La_{0.7}Sr_{0.3}MnO_{3}/Cu_{2}O/Co systems we find that a fraction of out-of-equilibrium spin polarized carrier actually travel across the Cu_{2}O layer up to distances of almost 100 nm at low temperature. The corresponding spin diffusion length dspin is estimated around 40 nm. Furthermore, we find that the insertion of a SrTiO_{3} tunneling barrier does not improve spin injection, likely due to the matching of resistances at the interfaces. Our result on dspin may be likely improved, both in terms of Cu_{2}O crystalline quality and sub-micrometric morphology and in terms of device geometry, indicating that Cu_{2}O is a potential material for efficient spin transport in devices based on crystalline oxides.Comment: 15 pages, 10 figure

Critical Field of MGB2 : Crossover from Clean to Dirty Regimes

We have studied the upper critical field, Bc2, in poly-crystalline MgB2 samples in which disorder was varied in a controlled way to carry selectively p and s bands from clean to dirty limit. We have found that the clean regime survives when p bands are dirty and s bands are midway between clean and dirty. In this framework we can explain the anomalous behaviour of Al doped samples, in which Bc2 decreases as doping increases.Comment: 11 pages, 2 figure

Sex-Specific Impacts of Exercise on Cardiovascular Remodeling

Cardiovascular diseases (CVD) remain the leading cause of death in men and women. Biological sex plays a major role in cardiovascular physiology and pathological cardiovascular remodeling. Traditionally, pathological remodeling of cardiovascular system refers to the molecular, cellular, and morphological changes that result from insults, such as myocardial infarction or hypertension. Regular exercise training is known to induce physiological cardiovascular remodeling and beneficial functional adaptation of the cardiovascular apparatus. However, impact of exercise-induced cardiovascular remodeling and functional adaptation varies between males and females. This review aims to compare and contrast sex-specific manifestations of exercise-induced cardiovascular remodeling and functional adaptation. Specifically, we review (1) sex disparities in cardiovascular function, (2) influence of biological sex on exercise-induced cardiovascular remodeling and functional adaptation, and (3) sex-specific impacts of various types, intensities, and durations of exercise training on cardiovascular apparatus. The review highlights both animal and human studies in order to give an all-encompassing view of the exercise-induced sex differences in cardiovascular system and addresses the gaps in knowledge in the field

Association between the multidimensional prognostic index and mortality during 15 Years of Follow-up in the InCHIANTI Study

Background: Multidimensional Prognostic Index (MPI) is recognized as a prognostic tool in hospitalized patients, but data on the value of MPI in community-dwelling older persons are limited. Using data from a representative cohort of community-dwelling persons, we tested the hypothesis that MPI explains mortality during 15 years of follow-up. Methods: A standardized comprehensive geriatric assessment was used to calculate the MPI and to categorize participants in low-, moderate-, and high-risk classes. The results were reported as hazard ratios (HRs) and the accuracy was evaluated with the area under the curve (AUC), with 95% confidence intervals (CIs) and the C-index. We also reported the median survival time by standard age groups. Results: All 1453 participants (mean age 68.9 years, women = 55.8%) enrolled in the InCHIANTI study at baseline were included. Compared to low-risk group, participants in moderate (HR = 2.10; 95% CI: 1.73-2.55) and high-risk MPI group (HR = 4.94; 95% CI: 3.91-6.24) had significantly higher mortality risk. The C-index of the model containing age, sex, and MPI was 82.1, indicating a very good accuracy of this model in explaining mortality. Additionally, the time-dependent AUC indicated that the accuracy of the model incorporating MPI to age and sex was excellent (>85.0) during the whole follow-up period. Compared to participants in the low-risk MPI group across different age groups, those in moderate- and high-risk groups survived 2.9-7.0 years less and 4.3-8.9 years less, respectively. Conclusions: In community-dwelling individuals, higher MPI values are associated with higher risk of all-cause mortality with a dose-response effect. © 2020 The Author(s) 2020

Enhanced flux pinning in neutron irradiated MgB2

We study the effect of neutron irradiation on the critical current density Jc of isotopically pure polycrystalline Mg11B2 samples. For fluences in the range 1017-1018 cm-2, Jc is enhanced and its dependence on magnetic field is significantly improved: we demonstrate that, in this regime, point-like pinning centers are effectively introduced in the system proportionally to the neutron fluence. Instead, for larger fluences, a strong suppression of the critical temperature accompanied by a decrease of both the upper critical field Bc2 and Jc is found.Comment: 13 pages, 3 igure

Re-rekruttering – et ubrukt potensial? Kan systematisk re-rekruttering av logistikkpersonell bidra til å dekke behovet for logistikk-kompetanse i Forsvaret?

Det moderniserte totalforsvarskonseptet tar utgangspunkt i koordinering av samfunnets samlede ressurser, og det er særlig innenfor logistikken at dette gjør seg gjeldende. Med det nye konseptet stilles det derfor nye krav til logistikk-kompetansen i Forsvaret. Forsvaret er avhengig av tilstrekkelig tilgang på personell med rett kompetanse for å løse sine samfunnsoppdrag. Innenfor logistikk er dette en knapphet i Forsvaret. Gjennom dialog med fratrådt logistikkpersonell, graduert fra Sjøkrigsskolen, vil oppgaven forsøke å besvare problemstillingen: Kan systematisk re-rekruttering av logistikkpersonell bidra til å dekke behovet for logistikkompetanse i Forsvaret? Oppgaven presenterer betydelige trender i opplevelsen av re-rekruttering i Forsvaret i dag. Denne dataen baserer seg på fratrådte logistikere fra graduasjonskull 2005 til 2017 ved Sjøkrigsskolens logistikklinje. Dataen er innhentet gjennom spørreundersøkelse og intervju, og drøftes i lys av de syv ulike prinsippene som ligger til grunn for planlegging og utøvelse av logistikk i Forsvaret, samt et modernisert totalforsvar. Oppsummert viser funnene at problemstillingen er sammensatt. Flere av respondentene opplever mer annerkjennelse og muligheter for egen utvikling og karriere i det sivile. Disse faktorene er deler av bakgrunnen for at flere valgte å slutte i Forsvaret, noe som bygger opp under forskningen til Bjelland og Stærkebye. Faktorene er også mye av årsaken til at logistikkpersonellet heller ikke ønsker å komme tilbake til Forsvaret gjennom re-rekruttering, ettersom de ikke ser tegn til endring siden de forlot organisasjonen. Det kan se ut til at Forsvaret ofte vil tape i kampen dersom personellet må velge mellom sivil eller militær sektor. Et tettere samarbeid med sivil sektor vil derfor kunne være en mer langsiktig løsning. Et slikt samarbeid innebærer at Forsvaret sitt kompetansekodeverk er fleksibelt nok til å anerkjenne kompetanse ervervet utenfor egen organisasjon. Et fleksibelt system vil i større grad gjøre det mulig å re-rekruttere tilbake fra sivil sektor. Re-rekruttering vil kunne begrense hullene som oppstår ved frafall, ettersom at personellet kommer tilbake igjen til Forsvaret med mer kompetanse enn da de dro. Det eksisterer ikke et tilstrekkelig system for slik innhenting av logistikkompetanse i dag. Re-rekrutteringen fremstår som tilfeldig og lite individualisert, og Forsvaret når dermed heller ikke ut til ønsket personell