Do the Herschel cold clouds in the Galactic halo embody its dark matter?

Recent Herschel/SPIRE maps of the Small and Large Magellanic Clouds (SMC, LMC) exhibit in each thousands of clouds. Observed at 250 microns, they must be cold, T ~ 15 K, hence the name "Herschel cold clouds" (HCCs). From the observed rotational velocity profile and the assumption of spherical symmetry, the Galactic mass density is modeled in a form close to that of an isothermal sphere. If the HCCs constitute a certain fraction of it, their angular size distribution has a specified shape. A fit to the data deduced from the SMC/LMC maps supports this and yields for their radius 2.5 pc, with a small change when allowing for a spread in HCC radii. There are so many HCCs that they will make up all the missing Halo mass density if there is spherical symmetry and their average mass is of order 15,000 Mo. This compares well with the Jeans mass of circa 40,000 Mo and puts forward that the HCCs are in fact Jeans clusters, constituting all the Galactic dark matter and much of its missing baryons, a conclusion deduced before from a different field of the sky (Nieuwenhuizen, Schild and Gibson 2011). A preliminary analysis of the intensities yields that the Jeans clusters themselves may consist of some billion MACHOs of a few dozen Earth masses. With a size of dozens of solar radii, they would mostly obscure stars in the LMC, SMC and towards the Galactic center, and may thus have been overlooked in microlensing.Comment: Revised and corrected version, matches published version. Conclusions unchange

Analisis Produksi dan Pendapatan USAhatani Kacang Tanah di Kabupaten Tapanuli Utara (Studi Kasus: Desa Banuaji IV, Kecamatan Adiankoting)

Penelitian ini bertujuan untuk mengetahui sistem USAhatani kacang tanah, tingkat produksi kacang tanah, faktor-faktor yang mempengaruhi tingkat produksi dan pendapatan USAhatani kacang tanah, serta layak atau tidaknya USAhatani kacang tanah dikembangkan di Desa Banuaji IV, Kecamatan Adiankoting, Kabupaten Tapanuli Utara. Pengambilan sampel dilakukan secara simple random sampling dengan jumlah sampel 30 KK berasal dari 255 KK. Metode penelitian yang digunakan adalah: skoring; analisis data deskriptif; Fungsi produksi Cobb-Douglass dan regresi linear berganda ; Analisis Usahatani rasio R/C. Hasil penelitian menunjukkan sistem USAhatani kacang tanah belum sesuai dengan sistem USAhatani anjuran, tingkat produksi kacang tanah tergolong rendah, faktor-faktor produksi yang mempengaruhi tingkat produksi kacang tanah adalah pupuk Phonska, TSP dan jumlah tenaga kerja, sementara faktor biaya produksi yang berpengarh nyata terhadap pendapatan USAhatani kacang tanah adalah biaya penyusutan peralatan, USAhatani kacang tanah layak dikembangkan di lokasi penelitian

Happiness, environmental protection and market economy

The manufacturing sector is leaving the West for Asia’s low wages and good working culture. Europe would be better off keeping these manufacturing activities, slowing down wage inflation and what is more, letting a young, cheaper workforce from the East settle down within their borders. This would aid in preserving the diverse economic structure which has been characteristic for Europe.Beside the economic growth there are two more concepts which have turned into the “holy cows” of economics during the last fifty years. One is the need to constantly improve labor productivity and the other is increasing competitiveness of nations. The high labor productivity of some countries, induces severe unemployment in the globalized world. In the other hand it is high time we understood that it is not competition, but cooperation that brings more happiness to humanity.Should we still opt for “happiness” and “sanity”, it is quite obvious that we all should, in economists’ terms, define our individual welfare functions corresponding to our own set of values, staying free from the influence of media, advertisements and fashion. The cornerstone to all this is the intelligent citizen who prefers local goods and services

Simulation of the hydrogen ground state in Stochastic Electrodynamics

Stochastic electrodynamics is a classical theory which assumes that the physical vacuum consists of classical stochastic fields with average energy $\frac{1}{2}\hbar \omega$ in each mode, i.e., the zero-point Planck spectrum. While this classical theory explains many quantum phenomena related to harmonic oscillator problems, hard results on nonlinear systems are still lacking. In this work the hydrogen ground state is studied by numerically solving the Abraham -- Lorentz equation in the dipole approximation. First the stochastic Gaussian field is represented by a sum over Gaussian frequency components, next the dynamics is solved numerically using OpenCL. The approach improves on work by Cole and Zou 2003 by treating the full $3d$ problem and reaching longer simulation times. The results are compared with a conjecture for the ground state phase space density. Though short time results suggest a trend towards confirmation, in all attempted modelings the atom ionises at longer times.Comment: 20 pages, 9 figures. Published version, minor change

OPE statistics from higher-point crossing

We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in d > 2. For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries.We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in $d>2$. For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries

Potential Vorticity Evolution of a Protoplanetary Disk with An Embedded Protoplanet

We present two-dimensional inviscid hydrodynamic simulations of a protoplanetary disk with an embedded planet, emphasizing the evolution of potential vorticity (the ratio of vorticity to density) and its dependence on numerical resolutions. By analyzing the structure of spiral shocks made by the planet, we show that progressive changes of the potential vorticity caused by spiral shocks ultimately lead to the excitation of a secondary instability. We also demonstrate that very high numerical resolution is required to both follow the potential vorticity changes and identify the location where the secondary instability is first excited. Low-resolution results are shown to give the wrong location. We establish the robustness of a secondary instability and its impact on the torque onto the planet. After the saturation of the instability, the disk shows large-scale non-axisymmetry, causing the torque on the planet to oscillate with large amplitude. The impact of the oscillating torque on the protoplanet's migration remains to be investigated.Comment: 17 pages total with 9 figures (Fig.4,5,9 are in .jpg), accepted to Ap

Fish schooling as a basis for vertical axis wind turbine farm design

Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighbouring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely-spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbours, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially-isolated turbine. A geometric arrangement based on the configuration of shed vortices in the wake of schooling fish is shown to significantly increase the array performance coefficient based upon an array of 16x16 wind turbines. Results suggest increases in power output of over one order of magnitude for a given area of land as compared to HAWTs.Comment: Submitted for publication in BioInspiration and Biomimetics. Note: The technology described in this paper is protected under both US and international pending patents filed by the California Institute of Technolog

Magnetic flux plays an important role during a BHXRB outburst in radiative 2T GRMHD simulations

Black hole (BH) X-ray binaries cycle through different spectral states of accretion over the course of months to years. Although fluctuations in the BH mass accretion rate are generally recognized as the most important component of state transitions, it is becoming increasingly evident that magnetic fields play a similarly important role. In this article, we present the first radiative two-temperature (2T) general relativistic magnetohydrodynamics (GRMHD) simulations in which an accretion disk transitions from a quiescent state at an accretion rate of $\dot{M} \sim 10^{-10} \dot{M}_{\rm Edd}$ to a hard-intermediate state at an accretion rate of $\dot{M} \sim 10^{-2} \dot{M}_{\rm Edd}$. This huge parameter space in mass accretion rate is bridged by artificially rescaling the gas density scale of the simulations. We present two jetted BH models with varying degrees of magnetic flux saturation. We demonstrate that in `Standard and Normal Evolution' models, which are unsaturated with magnetic flux, the hot torus collapses into a thin and cold accretion disk when $\dot{M} \gtrsim 5\times 10^{-3} \dot{M}_{\rm Edd}$. On the other hand, in `Magnetically Arrested Disk' models, which are fully saturated with vertical magnetic flux, the plasma remains mostly hot with substructures that condense into cold clumps of gas when $\dot{M} \gtrsim 1 \times 10^{-2} \dot{M}_{\rm Edd}$. This suggests that the spectral signatures observed during state transitions are closely tied to the level of magnetic flux saturation.Comment: 8 pages, 5 figures, accompanying animations included in YouTube playlist: https://www.youtube.com/playlist?list=PLDO1oeU33Gwm1Thyw0iHC14BbvBWaG5c