138 research outputs found
Eigen Modes and Ferromagnetic Resonance Line Width of Inhomogeneous Thin Films
In this paper, we describe modeling of the effects of magnetic inhomogeneity on ferromagnetic resonance line width using eigen mode analyses of inhomogeneous thin magnetic films
Truth, Justice or the American Way?
A review of current philosophy, research, and practice regarding the teaching of social justice reveals an unsettling paradox: While there has been a significant movement among educators to infuse and promote ideals of social justice within their curricula, this movement has been largely operating within a postmodern framework which, at its foundation, cannot sustain a unified theory of justice. Within such a postmodern framework, social justice pedagogy may be, at best, a well-intentioned but terribly fragmented social experiment, and at its worst, an unsettling prosecution of political hegemony. This paper will investigate the philosophical roots of this disconnect between theory and practice and the problems that it poses to public and higher education. As a corrective, we must explore the critical relationship between concepts of justice and concepts of truth, realizing that without a proper conception of truth, one cannot pursue (and therefore, presumably, teach) a proper view of justice. An outline of the biblical conception of truth and justice will be presented for the Christian educator who would take seriouslyâin theory and in practiceâthe call to promote justice within his/her sphere of influence as an integral part of Christian discipleship
Localized Ferromagnetic Resonance in Inhomogeneous Thin Films
The effect of sample inhomogeneity on the ferromagnetic resonance linewidth is determined by diagonalization of a spin wave Hamiltonian for ferromagnetic thin films with inhomogeneities spanning a wide range of characteristic length scales. A model inhomogeneity is used that consist of size D grains and an anisotropy field Hp that varies randomly from grain to grain in a film with thickness d and magnetization Ms. The resulting linewidth agrees well with the two-magnon model for small inhomogeneity, HpD « ÏMsd. For large inhomogeneity, HpD » ÏMsd the precession becomes localized and the spectrum approaches that of local precession on independent grains
Das Achmer Grasmoor : vegetations- und bodenkundliche Untersuchungen im Hinblick auf die Entwicklung und Sicherung des Gebietes
Das Grasmoor bei Achmer im Landkreis OsnabrĂŒck ist ein von Kiefernforsten geprĂ€gtes DĂŒnengebiet mit zahlreichen nassen Senken. Es kommen StillgewĂ€sser, BruchwĂ€lder, Anmoore, Nieder- und Ăbergangsmoore sowie wechselnasse Standorte vor, die eine unterschiedliche AusprĂ€gung in bezug auf die NĂ€hrstoffversorgung, den Wasserhaushalt und den Grad der menschlichen Beeinflussung aufweisen. Das Gebiet wurde von April 1993 bis Februar 1994 untersucht. Seit der Unterschutzstellung von Teilen des Gebietes im Jahre 1937 haben sich erhebliche VerĂ€nderungen vollzogen. Der FlĂ€chenanteil der Feuchtgebiete ist durch die Anlage von GrĂ€ben deutlich zurĂŒckgegangen. Es sind nahezu ĂŒberall Degenerationserscheinungen festzustellen, doch sind noch ausgedehnte naturnahe Feuchtgebiete erhalten geblieben, und das Gebiet weist insgesamt einen hohen Wert fĂŒr den Arten- und Biotopschutz auf. Besonders groĂ ist derzeit die GefĂ€hrdung zweier Moorkomplexe, die nördlich des bestehenden Naturschutzgebietes liegen und von denen nur noch Teilbereiche als wachsendes Ăbergangsmoor anzusehen sind. Sie stellen potentielle ErweiterungsflĂ€chen des Naturschutzgebietes dar. In den letzten 20 Jahren hat eine starke Verbuschung eingesetzt, die seit etwa 1987 extrem zunimmt. Es wird deutlich, daĂ die bestehende Naturschutzgebietsverordnung keinen effektiven Schutz der Feuchtgebiete darstellt. Zudem zeigt es sich, daĂ in groĂen Teilbereichen eine forstliche Nutzung mit den Belangen des Naturschutzes nicht vereinbar ist. Das Grasmoor stellt noch eines der wertvollsten Heideweiherund Moorgebiete im Landkreis OsnabrĂŒck mit Pflanzen und Tieren der Nieder-, Ăbergangs- und Hochmoore dar. Ohne sofortige, umfassende Schutz-, Pflege- und EntwicklungsmaĂnahmen ist eine nachhaltige Sicherung vermutlish nicht möglich.The Grasmoor near Achmer in the district of OsnabrĂŒck is a sand dune area, influenced by pine forests and rich in wet shallow depressions. There you can find standing water, carr, early bogs, fen and transitory bogs and poikilohydrous sites that reveal a different mark concerning their nutrient supply, water balance and the grade of influence by man. The area was analysed from April 1993 to February 1994. Since parts of the area were put under protection in 1937 there have been immense changes. The humid part of the area has been obviously reduced because of the construction of digs. Nearly everywhere degenerate phenomena can be observed, but there are still expanded humid areas in a good condition and the whole bog is of great importance for the protection of species and biotope. At present there is an extremely high risk for the two bog areas which are situated in the north of the existing nature reserve and from which parts are just growing transitory bogs. They are potential expansion areas of the nature reserve. Over the last twenty years many bushes have begun to grow there and this growth has even been increasing since about 1987. It is obvious that the actual decree for nature reserves cannot guarantee an effective protection of the humid areas. Besides, the situation shows that in large areas of the Grasmoor forestry use is incompatible with interests of nature. The Grasmoor is one of the most precious moorland and bog areas in the district of OsnabrĂŒck with wild plants and animals of the fen, transitory and peat bogs. Without immediate steps being taken to protect, take care of and develop the Grasmoor, it's long-term security will be impossible
Ferromagnetic resonance study of sputtered Co|Ni multilayers
We report on room temperature ferromagnetic resonance (FMR) studies of [
Co Ni]N sputtered films, where nm. Two
series of films were investigated: films with same number of CoNi bilayer
repeats (N=12), and samples in which the overall magnetic layer thickness is
kept constant at 3.6 nm (N=1.2/). The FMR measurements were conducted with a
high frequency broadband coplanar waveguide up to 50 GHz using a flip-chip
method. The resonance field and the full width at half maximum were measured as
a function of frequency for the field in-plane and field normal to the plane,
and as a function of angle to the plane for several frequencies. For both sets
of films, we find evidence for the presence of first and second order
anisotropy constants, and . The anisotropy constants are strongly
dependent on the thickness , and to a lesser extent on the total thickness
of the magnetic multilayer. The Land\'e g-factor increases with decreasing
and is practically independent of the multilayer thickness. The magnetic
damping parameter , estimated from the linear dependence of the
linewidth, , on frequency, in the field in-plane geometry,
increases with decreasing . This behaviour is attributed to an enhancement
of spin-orbit interactions with decreasing and in thinner films, to a
spin-pumping contribution to the damping.Comment: 18 pages, 13 figure
Influence of randomness and retardation on the FMR-linewidth
The theory predicts that the spin-wave lifetime and the linewidth of
ferromagnetic resonance can be governed by random fields and spatial
memory. To that aim the effective field around which the magnetic moments
perform a precession is superimposed by a stochastic time dependent magnetic
field with finite correlation time. The magnetization dynamics is altered by
inclusion of a spatial memory effect monitoring a non-local interaction of size
. The underlying Landau-Lifshitz-Gilbert equation (LLG) is modified
accordingly. The stochastic LLG is equivalent to a Fokker-Planck equation which
enables to calculate the mean values of the magnetization vector. Within the
spin-wave approximation we present an analytical solution for the excitation
energy and its damping. The lifetime and the linewidth are analyzed depending
on the strength of the random field and its correlation time as
well as the retardation strength and the size . Whereas
decreases with increasing , retardation strength and
, the lifetime is enhanced for growing width of the spatial
retardation kernel. In the same manner we calculate the experimentally
measurable linewidth is increased strongly when the correlation time
ranges in the nanosecond interval.Comment: 20 pages, 4 figure
Awareness and knowledge of sexually transmitted diseases (STDs) among school-going adolescents in Europe: a systematic review of published literature
Samkange-Zeeb FN, Spallek L, Zeeb H. Awareness and knowledge of sexually transmitted diseases (STDs) among school-going adolescents in Europe: a systematic review of published literature. BMC public health. 2011;11(1): 727.BACKGROUND: Sexually transmitted diseases (STDs) are a major health problem affecting mostly young people, not only in developing, but also in developed countries.We conducted this systematic review to determine awareness and knowledge of school-going male and female adolescents in Europe of STDs and if possible, how they perceive their own risk of contracting an STD. Results of this review can help point out areas where STD risk communication for adolescents needs to be improved. METHODS: Using various combinations of the terms "STD", "HIV", "HPV", "Chlamydia", "Syphilis", "Gonorrhoea", "herpes", "hepatitis B", "knowledge", "awareness", and "adolescents", we searched for literature published in the PubMed database from 01.01.1990 up to 31.12.2010. Studies were selected if they reported on the awareness and/or knowledge of one or more STD among school-attending adolescents in a European country and were published in English or German. Reference lists of selected publications were screened for further publications of interest. Information from included studies was systematically extracted and evaluated. RESULTS: A total of 15 studies were included in the review. All were cross-sectional surveys conducted among school-attending adolescents aged 13 to 20 years. Generally, awareness and knowledge varied among the adolescents depending on gender.Six STDs were focussed on in the studies included in the review, with awareness and knowledge being assessed in depth mainly for HIV/AIDS and HPV, and to some extent for chlamydia. For syphilis, gonorrhoea and herpes only awareness was assessed. Awareness was generally high for HIV/AIDS (above 90%) and low for HPV (range 5.4%-66%). Despite knowing that use of condoms helps protect against contracting an STD, some adolescents still regard condoms primarily as an interim method of contraception before using the pill. CONCLUSION: In general, the studies reported low levels of awareness and knowledge of sexually transmitted diseases, with the exception of HIV/AIDS. Although, as shown by some of the findings on condom use, knowledge does not always translate into behaviour change, adolescents' sex education is important for STD prevention, and the school setting plays an important role. Beyond HIV/AIDS, attention should be paid to infections such as chlamydia, gonorrhoea and syphilis
EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol
This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) deals with the setting of Dietary Reference Values (DRVs) for fats. A lower bound of the reference intake range for total fat of 20 energy % (E%) and an upper bound of 35 E% are proposed. Fat intake in infants can gradually be reduced from 40 E% in the 6-12 month period to 35-40 E% in the 2nd and 3rd year of life. For specific fatty acids the following is proposed: saturated fatty acid (SFA) and trans fatty acid intake should be as low as possible; not to set any DRV for cis-monounsaturated fatty acids; not to formulate a DRV for the intake of total cis-polyunsaturated fatty acids (PUFA); not to set specific values for the n-3/n-6 ratio; to set an Adequate Intake (AI) of 4 E% for linolenic acid; not to set any DRV for arachidonic acid; not to set an UL for total or any of the n-6 PUFA; to set an AI for alpha-linilenic acid (ALA) of 0.5 E%; not to set an UL for ALA; to set an AI of 250 mg for eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) for adults; to set an AI of 100 mg DHA for infants (>6 months) and young children <24 months; to increase by 100-200 mg preformed DHA in addition to the AI for adults as an adequate supply of n-3 long chain PUFA during pregnancy and lactation; not to set any DRV for conjugated linoleic acid. For cholesterol it was decided not to propose a reference value beside the limitation on the intake of SF
- âŠ