1,104 research outputs found
Spin and orbital moments of ultra-thin Fe films on various semiconductor surfaces
The magnetic moments of ultrathin Fe films on three different III-V semiconductor substrates, namely GaAs, InAs and In0.2Ga0.8As have been measured with X-ray magnetic circular dichroism at room temperature to assess their relative merits as combinations suitable for next-generation spintronic devices. The results revealed rather similar spin moments and orbital moments for the three systems, suggesting the relationship between film and semiconductor lattice parameters to be less critical to magnetic moments than magnetic anisotropy
Non-Gaussian Features of Transmitted Flux of QSO's Ly Absorption: Intermittent Exponent
We calculate the structure function and intermittent exponent of the 1.) Keck
data, which consists of 29 high resolution, high signal to noise ratio (S/N)
QSO Ly absorption spectra, and 2.)the Ly forest simulation
samples produced via the pseudo hydro scheme for the low density cold dark
matter (LCDM) model and warm dark matter (WDM) model with particle mass
and 1000 eV. These two measures detect not only
non-gaussianities, but also the type of non-gaussianty in the the field. We
find that, 1.) the structure functions of the simulation samples are
significantly larger than that of Keck data on scales less than about 100
h kpc, 2.) the intermittent exponent of the simulation samples is more
negative than that of Keck data on all redshifts considered, 3.) the
order-dependence of the structure functions of simulation samples are closer to
the intermittency of hierarchical clustering on all scales, while the Keck data
are closer to a lognormal field on small scales. These differences are
independent of noise and show that the intermittent evolution modeled by the
pseudo-hydro simulation is substantially different from observations, even
though they are in good agreement in terms of second and lower order
statistics. (Abridged)Comment: 17 pages, 13 figures. Accepted by Ap
Calculations of the Local Density of States for some Simple Systems
A recently proposed convolution technique for the calculation of local
density of states is described more thouroughly and new results of its
application are presented. For separable systems the exposed method allows to
construct the ldos for a higher dimensionality out of lower dimensional parts.
Some practical and theoretical aspects of this approach are also discussed.Comment: 5 pages, 3 figure
Evidence for density dependent population regulation in southern elephant seals in the southern Indian Ocean
The means by which populations are regulated form a central theme in conservation biology, and much debate has revolved around density dependence as a mechanism driving population change. Marion Island (46o54'S, 37o45'E) is host to a relatively small breeding population of southern elephant seals, which like its counterparts in the southern Indian and southern Pacific Oceans, have declined precipitously over the past few decades. An intensive mark-recapture study, which commenced in 1983, has yielded a long time-series of resight data on this population. We used the program MARK to estimate adult female survival in this population from resight data collected over the period 1986-1999. Including concurrent population counts as covariates significantly improved our mark-recapture models and suggests density dependent population regulation to be operational in the population. Although predation may have been involved, it is far more likely that density dependent regulation has been based on a limited food supply. A significant increase in adult female survival was evident which is likely to have given rise to recent changes in population growth
Constraints on massive gravity theory from big bang nucleosynthesis
The massive gravity cosmology is studied in the scenario of big bang
nucleosynthesis. By making use of current bounds on the deviation from the
fractional mass, we derive the constraints on the free parameters of the
theory. The cosmological consequences of the model are also discussed in the
framework of the PAMELA experiment.Comment: 5 page
Genomic Prognosticators and Extent of Resection in Molecularly Subtyped World Health Organization Grade II and III Gliomas–A Single-Institution, Nine-Year Data
BACKGROUND: WHO grade II and III IDH wild-type (IDH-wt) gliomas are often treated as WHO grade IV glioblastomas. However, cumulative evidence indicates that IDH mutation status alone is insufficient in predicting survival. The current study examines molecular and clinical markers to further prognostically stratify WHO grade II and III gliomas, in particular, IDH-wt. METHODS: A single institution's records were retrospectively reviewed for molecularly stratified WHO grade II and grade III gliomas over a nine-year period (2010-2019). Clinical data, IDH1/IDH2 status, EGFR amplification and other molecular markers were recorded and correlated to the study outcomes. These were defined as progression-free survival (PFS), overall survival (OS) and time to malignant progression (TtMP). RESULTS: 167 and 42 WHO grade II and III gliomas, respectively, were identified, totalling 209 cases with 157 IDH1/2 mutated and 52 IDH wild-type tumours. The presence of IDH1/2 mutation was associated with longer OS (p<0.0001) and PFS (p<0.0001) but not with TtMP (p=0.314). Lack of EGFR amplification, younger age, greater extent of resection (EOR) (≥80%) were identified as independent, favourable prognostic factors. In the IDH-wt cohort, multivariate analysis indicated that older age (p=0.003) and lesser EOR (<80%) (p=0.007) are associated with worse OS. Additionally, EGFR amplification showed a trend toward shorter OS in the IDH-wt cohort (p=0.073). CONCLUSIONS: IDH1/2 mutation favours longer OS and PFS but does not protect from malignant progression. Lack of EGFR amplification, older age and greater EOR are favourable OS prognosticators. In the IDH-wt cohort, older age and lesser EOR were linked to worse OS
Ісламський фактор в міжнародних економічних відносинах: приклад ЄС і Турції
В роботі представлена спроба цілісного вивчення впливу культурних, соціальних, економічних і політичних факторів на процеси взаємовідносин Туреччини і ЄС, що дозволяє надати більш об'ємне й глибоке уявлення про соціально-політичні процеси в Туреччині і ЄС в контексті їх еволюції. Дана оцінка сучасного стану мусульманської діаспори в країнах ЄС з подальшою систематизацією даних. Зроблена авторська порівняльна характеристика процесів євроінтеграції України (у якої є свій «ісламський» фактор) і Туреччини і її систематизаці
Dynamical approach to chains of scatterers
Linear chains of quantum scatterers are studied in the process of
lengthening, which is treated and analysed as a discrete dynamical system
defined over the manifold of scattering matrices. Elementary properties of such
dynamics relate the transport through the chain to the spectral properties of
individual scatterers. For a single-scattering channel case some new light is
shed on known transport properties of disordered and noisy chains, whereas
translationally invariant case can be studied analytically in terms of a simple
deterministic dynamical map. The many-channel case was studied numerically by
examining the statistical properties of scatterers that correspond to a certain
type of transport of the chain i.e. ballistic or (partially) localised.Comment: 16 pages, 7 figure
EVALUATION OF PREHOSPITAL BLOOD PRODUCTS TO ATTENUATE ACUTE COAGULOPATHY OF TRAUMA IN A MODEL OF SEVERE INJURY AND SHOCK IN ANESTHETIZED PIGS
This material is licensed under the terms of the Open Government Licence except where otherwise statedUK Ministry of Defence
BBN and the Primordial Abundances
The relic abundances of the light elements synthesized during the first few
minutes of the evolution of the Universe provide unique probes of cosmology and
the building blocks for stellar and galactic chemical evolution, while also
enabling constraints on the baryon (nucleon) density and on models of particle
physics beyond the standard model. Recent WMAP analyses of the CBR temperature
fluctuation spectrum, combined with other, relevant, observational data, has
yielded very tight constraints on the baryon density, permitting a detailed,
quantitative confrontation of the predictions of Big Bang Nucleosynthesis with
the post-BBN abundances inferred from observational data. The current status of
this comparison is presented, with an emphasis on the challenges to astronomy,
astrophysics, particle physics, and cosmology it identifies.Comment: To appear in the Proceedings of the ESO/Arcetri Workshop on "Chemical
Abundances and Mixing in Stars in the Milky Way and its Satellites", eds., L.
Pasquini and S. Randich (Springer-Verlag Series, "ESO Astrophysics Symposia"
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