12,708 research outputs found
Integral equation for inhomogeneous condensed bosons generalizing the Gross-Pitaevskii differential equation
We give here the derivation of a Gross-Pitaevskii--type equation for
inhomogeneous condensed bosons. Instead of the original Gross-Pitaevskii
differential equation, we obtain an integral equation that implies less
restrictive assumptions than are made in the very recent study of Pieri and
Strinati [Phys. Rev. Lett. 91 (2003) 030401]. In particular, the Thomas-Fermi
approximation and the restriction to small spatial variations of the order
parameter invoked in their study are avoided.Comment: Phys. Rev. A (accepted
Practical dispersion relations for strongly coupled plasma fluids
Very simple explicit analytical expressions are discussed, which are able to
describe the dispersion relations of longitudinal waves in strongly coupled
plasma systems such as one-component plasma and weakly screened Yukawa fluids
with a very good accuracy. Applications to other systems with soft pairwise
interactions are briefly discussed.Comment: 11 pages, 3 figures; Related to arXiv:1711.0615
Tiergesundheit als Faktor des Qualitätsmanagements in der ökologischen Milchviehhaltung - Eine Interventions- und Coaching-Studie zur Anwendung präventiver Tiergesundheitskonzepte
Ziel des ersten Projektteils war es, (1) ein präventives Tiergesundheitskonzept für die ökologische Milchviehhaltung am Beispiel von Lahmheiten zu entwickeln und (2) dieses Managementkonzept anhand einer Interventionsstudie zu validieren sowie dessen Praxistauglichkeit zu demonstrieren. Über einen Zeitraum von drei Jahren (2005-2007) wurde die Lahmheitssituation auf insgesamt 43 ökologisch wirtschaftenden Milchviehbetrieben verfolgt. Die Lahmheitsprävalenz ging in den 21 Interventionsbetrieben, für die mit den BetriebsleiterInnen betriebsindividuelle Maßnahmenkataloge erarbeitet worden waren, konsistent und signifikant stärker zurück als in den Kontrollbetrieben (Intervention: -18,3 % (absolut); Kontrolle: -4,5 %).
Der zweite Projektteil hatte zum Ziel, (1) zentrale Indikatoren für die Milchviehgesundheit zu identifizieren und Zielgrößen zu definieren (Mastitis, Lahmheiten, Stoffwechselstörungen, Fruchtbarkeitsstörungen, Kälbererkrankungen), (2) Leitlinien für die Entwicklung von Herdengesundheitsplänen zu erstellen und (3) die Umsetzbarkeit und Effektivität auf Praxisbetrieben unter Einbindung von Betriebsleiter-, Berater- und HoftierärztInnen zu untersuchen. Dazu wurden 44 Bio-Milchviehbetriebe in den Jahren 2006 und 2007 insgesamt vier Mal besucht. Nach einzelbetrieblichen Schwachstellenanalysen wurden in 28 Betrieben unter Berücksichtigung der o.g. Zielgrößen betriebsindividuelle Tiergesundheitspläne erstellt und die Entwicklung der Tiergesundheit im Jahr 2007 für Interventions- und Kontrollbetriebe verfolgt. Ein Jahr nach Einführung der Tiergesundheitspläne ging die Behandlungsinzidenz von klinischen Mastitiden in Betrieben, die diesbezügliche Maßnahmen umgesetzt hatten, signifikant stärker zurück, als in den Kontrollbetrieben. Für andere Indikatoren ließ sich keine Verbesserung der Tiergesundheit absichern; dabei muss jedoch der kurze Beobachtungszeitraum berücksichtigt werden
Phase transitions near black hole horizons
The Reissner-Nordstrom black hole in four dimensions can be made unstable
without violating the dominant energy condition by introducing a real massive
scalar with non-renormalizable interactions with the gauge field. New stable
black hole solutions then exist with greater entropy for fixed mass and charge
than the Reissner-Nordstrom solution. In these new solutions, the scalar
condenses to a non-zero value near the horizon. Various generalizations of
these hairy black holes are discussed, and an attempt is made to characterize
when black hole hair can occur.Comment: 30 pages, 6 figures. v2: minor corrections, references adde
Statistical Description of Hydrodynamic Processes in Ionic Melts with taking into account Polarization Effects
Statistical description of hydrodynamic processes for ionic melts is proposed
with taking into account polarization effects caused by the deformation of
external ionic shells. This description is carried out by means of the Zubarev
nonequilibrium statistical operator method, appropriate for investigations of
both strong and weak nonequilibrium processes. The nonequilibrium statistical
operator and the generalized hydrodynamic equations that take into account
polarization processes are received for ionic-polarization model of ionic
molten salts when the nonequilibrium averaged values of densities of ions
number, their momentum, dipole momentum and total energy are chosen for the
reduced description parameters. A spectrum of collective excitations is
investigated within the viscoelastic approximation for ion-polarization model
of ionic melts.Comment: 24 pages, RevTex4.1-format, no figure
The evidence-based pharmacological treatment of paediatric ADHD.
Attention deficit hyperactivity disorder (ADHD) is common in children, adolescents, and adults, with extensive research establishing it as a valid neurobiological disorder. Without intervention, ADHD can result in significant impairment throughout the lifespan for the individuals it afflicts. Fortunately, multiple evidence-based options are available for the treatment of ADHD, including several efficacious pharmacotherapies. The role of medication, including stimulants as well as non-stimulants, is well-documented by an extensive body of literature. Although there may be less enthusiasm for behavioural and other psychosocial interventions as stand-alone treatments for moderate to severe ADHD, they are recommended as first-line treatment for ADHD management in preschool-aged children, for those patients with mild symptoms, and as an adjunct to medication in patients with comorbid disorders or suboptimal responses to pharmacotherapy. When planning treatment for individuals with ADHD, the potential risks associated with the available interventions must be carefully balanced against the risks of not treating, or not treating adequately. The treatment plan must also include ongoing re-assessment of the effectiveness of and the need for continued therapy. Recent practice parameters provide further specific guidance for the evidence-based assessment and treatment of children and adolescents with ADHD
TeV scale resonant leptogenesis from supersymmetry breaking
We propose a model of TeV-scale resonant leptogenesis based upon recent
models of the generation of light neutrino masses from supersymmetry-breaking
effects with TeV-scale right-handed (rhd) neutrinos, . The model leads to
naturally large cosmological lepton asymmetries via the resonant behaviour of
the one-loop self-energy contribution to decay. Our model addresses the
primary problems of previous phenomenological studies of low-energy
leptogenesis: a rational for TeV-scale rhd neutrinos with small Yukawa
couplings so that the out-of equilibrium condition for decay is
satisfied; the origin of the tiny, but non-zero mass splitting required between
at least two masses; and the necessary non-trivial breaking of flavour
symmetries in the rhd neutrino sector. The low mass-scale of the rhd neutrinos
and their superpartners, and the TeV-scale -terms automatically contained
within the model offer opportunities for partial direct experimental tests of
this leptogenesis mechanism at future colliders.Comment: 10 Pages latex, version for JHE
Substructure Boosts to Dark Matter Annihilation from Sommerfeld Enhancement
The recently introduced Sommerfeld enhancement of the dark matter
annihilation cross section has important implications for the detection of dark
matter annihilation in subhalos in the Galactic halo. In addition to the boost
to the dark matter annihilation cross section from the high densities of these
subhalos with respect to the main halo, an additional boost caused by the
Sommerfeld enhancement results from the fact that they are kinematically colder
than the Galactic halo. If we further believe the generic prediction of CDM
that in each subhalo there is an abundance of substructure which is
approximately self-similar to that of the Galactic halo, then I show that
additional boosts coming from the density enhancements of these small
substructures and their small velocity dispersions enhance the dark matter
annihilation cross section even further. I find that very large boost factors
( to ) are obtained in a large class of models. The implications of
these boost factors for the detection of dark matter annihilation from dwarf
Spheroidal galaxies in the Galactic halo are such that, generically, they
outshine the background gamma-ray flux and are detectable by the Fermi
Gamma-ray Space Telescope.Comment: PRD in pres
Ă–kologischer Landbau in Deutschland: Ein aktuelles Stimmungsbild aus der Praxis
In order explore the past development, the current situation and the future prospects of organic farming in Germany from a farm , a nationwide survey has been carried out. In total, 218 organic farms from all over Germany who participated in
a comprehensive status quo analysis of organic farming in the year 2002/2003 were asked to participate in a follow-up survey fourteen years later. 92 organic farms agreed to do so. Most of them assess the current situation positively. Also their current income situation and the general development opportunities in organic farming make them optimistic. Growth opportunities and the assessments of the lease market however are described in a rather negative light. The evaluation of the vocational training in organic farming is seen as inadequate and illustrates a need for action at this point
- …