Effects of Unstable Dark Matter on Large-Scale Structure and Constraints from Future Surveys

In this paper we explore the effect of decaying dark matter (DDM) on large-scale structure and possible constraints from galaxy imaging surveys. DDM models have been studied, in part, as a way to address apparent discrepancies between the predictions of standard cold dark matter models and observations of galactic structure. Our study is aimed at developing independent constraints on these models. In such models, DDM decays into a less massive, stable dark matter (SDM) particle and a significantly lighter particle. The small mass splitting between the parent DDM and the daughter SDM provides the SDM with a recoil or "kick" velocity vk, inducing a free-streaming suppression of matter fluctuations. This suppression may be probed via weak lensing power spectra measured by a number of forthcoming imaging surveys that aim primarily to constrain dark energy. Using scales on which linear perturbation theory alone is valid (multipoles < 300), surveys like Euclid or LSST can be sensitive to vk > 90 km/s for lifetimes ~ 1-5 Gyr. To estimate more aggressive constraints, we model nonlinear corrections to lensing power using a simple halo evolution model that is in good agreement with numerical simulations. In our most ambitious forecasts, using multipoles < 3000, we find that imaging surveys can be sensitive to vk ~ 10 km/s for lifetimes < 10 Gyr. Lensing will provide a particularly interesting complement to existing constraints in that they will probe the long lifetime regime far better than contemporary techniques. A caveat to these ambitious forecasts is that the evolution of perturbations on nonlinear scales will need to be well calibrated by numerical simulations before they can be realized. This work motivates the pursuit of such a numerical simulation campaign to constrain dark matter with cosmological weak lensing.Comment: 15 pages, 7 figures. Submitted to PR

Universal Thermoelectric Effect of Dirac Fermions in Graphene

We numerically study the thermoelectric transports of Dirac fermions in graphene in the presence of a strong magnetic field and disorder. We find that the thermoelectric transport coefficients demonstrate universal behavior depending on the ratio between the temperature and the width of the disorder-broadened Landau levels(LLs). The transverse thermoelectric conductivity $\alpha_{xy}$ reaches a universal quantum value at the center of each LL in the high temperature regime, and it has a linear temperature dependence at low temperatures. The calculated Nernst signal has a peak at the central LL with heights of the order of $k_B/e$, and changes sign near other LLs, while the thermopower has an opposite behavior, in good agreement with experimental data. The validity of the generalized Mott relation between the thermoelectric and electrical transport coefficients is verified in a wide range of temperatures.Comment: 4 pages, 4 figures, published versio

Efktifitas Baby Solus Per Aqua (Spa) terhadap Peningkatan Berat Badan dengan Bayi Berat Badan Rendah Usia 7 Bulan

Pelayanan SPA merupakan bagian dari upaya pelayanan kesehatan tradisional yang sekaligus sebagai upaya pelestarian budaya/pusaka nusantara .Menurut penelitian yang dilakukan oleh ilmuan dan Institut Griffith For Educational Research 2007. Mereka menelliti orang tua dari 7000 anak di Astralia, Selandia Baru dan Amerika Serikat. Anak-anak yang dilibatkan dalam penelitian ini semuanya berusia di baah 1 tahun dan penelitian berlangsung selama 3 tahun. Profesor Robyn Jourgensen, yang memimpin penelitian itu mengatakan, anak-anak yang belajar berenang di usia dini memiliki banyak keterampilan dan mencapai titik pertumbuhan yang lebih cepat. 20 bayi prematur (berat badan 1280 dan 1176 Gram), yang di pijit 3 kali 15 menit selama 10 hari, mengalami kenaikan berat badan perhari 20% - 47% lebih banyak dari yang tidak dipijat. Penelitian pada bayi cukup bulan yang berusia 1-3 bulan, yang di pijat 15 menit, 2 kali seminggu selama 6 minggu juga didapatkan kenaikan berat badan 50% yang lebih dari kontrol. Jenis penelitian ini adalah survei eksplanotori yang bertujuan menjelaskan hubungan kausal antara variabel-variabel yang diteliti. Penelitian dilaksanakan di Wilayah kerja Puskesmas Simpang Limun. Di dalam penelitian ini, peneliti akan meneliti beberapa variabelEfektifitas Baby Solus Per Aqua (SPA) Terhadap Peningkatan Berat Badan Dengan Bayi Berat Badan Rendah Usia 4-9 BulanPemilihan variabel-variabel dalam penelitian ini didasarkan pada perilaku.&nbsp; Penelitian ini merupakan penelitiankuantitatif dengan, menggunakan desain quasi experiment pre post design with a comparison group karena dalam penelitian ini peneliti memberikan Intervensi atau intervensi pada subjek penelitian, kemudian Intervensi diukur dan dianalisis. Instrumen dibangun dengan mendalami teori dan konsep pada masing-masing variabel serta pengaruh dari satu variabel ke variabel lainnya.&nbsp; Hasil dari penelitian ini akan menciptakan suatu Perubahan perilaku masyarakat agar dapat mempraktekkan Baby Spa terhadap bayi ibu tersebut agar pertumbuhan dan perkembangan bayi dapat bertumbuh dengan baik

Formation epochs, star formation histories and sizes of massive early-type galaxies in cluster and field environments at z=1.2: insights from the rest-frame UV

We derive stellar masses, ages and star formation histories of massive early-type galaxies in the z=1.237 RDCS1252.9-2927 cluster and compare them with those measured in a similarly mass-selected sample of field contemporaries drawn from the GOODS South Field. Robust estimates of these parameters are obtained by comparing a large grid of composite stellar population models with 8-9 band photometry in the rest-frame NUV, optical and IR, thus sampling the entire relevant domain of emission of the different stellar populations. Additionally, we present new, deep $U$-band photometry of both fields, giving access to the critical FUV rest-frame, in order to constrain empirically the dependence on the environment of the most recent star formation processes. We find that early-type galaxies, both in the cluster and in the field, show analogous optical morphologies, follow comparable mass vs. size relation, have congruent average surface stellar mass densities and lie on the same Kormendy relation. We also that a fraction of early-type galaxies in the field employ longer timescales, $\tau$, to assemble their mass than their cluster contemporaries. Hence we conclude that, while the formation epoch of early-type only depends on their mass, the environment does regulate the timescales of their star formation histories. Our deep $U$-band imaging strongly supports this conclusions. It shows that cluster galaxies are at least 0.5 mag fainter than their field contemporaries of similar mass and optical-to-infrared colors, implying that the last episode of star formation must have happened more recently in the field than in the cluster.Comment: 20pages, 10 figures. to appear on Ap

Persepsi Masyarakat terhadap Resiko Bencana Longsor di Dusun Blawong Kulon Desa Muncar Kecamatan Gemawang Kabupaten Temanggung

Dusun Blawong Kulon merupakan salah satu Dusun di Kabupaten Temanggung yang mempunyai resiko bencana longsor yang tinggi. Penelitian ini dilakukan untuk mengetahui persepsi resiko masyarakat terhadap bencana longsor. Penelitian ini bertujuan untuk a) Mengidentifikasi pengetahuan masyarakat terhadap ancaman bencana longsor b)Menganalisis persepsi resiko masyarakat terhadap ancaman bencana longsor c) Mengetahui upaya penanggulangan bencana yang dilakukan masyarakat dalam menghadapi ancaman bencana longsor. Metode kuantitatif digunakan untuk memperoleh data dengan menggunakan kuesioner dan skala likert serta menggunakan analisis statistik deskriptik dengan pemilihan sampel menggunakan probability sampling yaitu cluster sampling. Pengambilan sampel berada di delapan RT (Rumah Tangga) yang tersebar di Dusun Blawong Kulon dengan jumlah sampel 80 unit dengan unit Rumah Tangga. Hasil penelitian yang diperoleh adalah a) Penduduk Dusun Blawong Kulon mempunyai pengetahuan yang tinggi mengenai bencana longsor b) Penduduk Dusun Blawong Kulon mempunyai persepsi positif terhadap bencana longsor dengan agregat skala likert sebesar 60,8% c) dan sebanyak 51% penduduk Dusun Blawong Kulon mempunyai upaya penanggulangan bencana yang tinggi

Strain induced half-metal to semiconductor transition in GdN

We have investigated the electronic structure and magnetic properties of GdN as a function of unit cell volume. Based on the first-principles calculations of GdN, we observe that there is a transformation in conduction properties associated with the volume increase: first from halfmetallic to semi-metallic, then ultimately to semiconducting. We show that applying stress can alter the carrier concentration as well as mobility of the holes and electrons in the majority spin channel. In addition, we found that the exchange parameters depend strongly on lattice constant, thus the Curie temperature of this system can be enhanced by applying stress or doping impurities.Comment: 9 pages, 3 figure

Classification of multipartite entanglement containing infinitely many kinds of states

We give a further investigation of the range criterion and Low-to-High Rank Generating Mode (LHRGM) introduced in \cite{Chen}, which can be used for the classification of $2\times{M}\times{N}$ states under reversible local filtering operations. By using of these techniques, we entirely classify the family of $2\times4\times4$ states, which actually contains infinitely many kinds of states. The classifications of true entanglement of $2\times(M+3)\times(2M+3)$ and $2\times(M+4)\times(2M+4)$ systems are briefly listed respectively.Comment: 11 pages, revte

Coherent Population Trapping of Electron Spins in a Semiconductor

In high-purity n-type GaAs under strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various EIT-type experiments.Comment: 5 pages, 4 figures replaced 6/25/2007 with PRL versio