103 research outputs found
Gamma-rays from ultracompact minihalos: potential constraints on the primordial curvature perturbation
Ultracompact minihalos (UCMHs) are dense dark matter structures which can
form from large density perturbations shortly after matter-radiation equality.
If dark matter is in the form of Weakly Interacting Massive Particles (WIMPs),
then UCMHs may be detected via their gamma-ray emission. We investigate how the
{\em{Fermi}} satellite could constrain the abundance of UCMHs and place limits
on the power spectrum of the primordial curvature perturbation. Detection by
{\em Fermi} would put a lower limit on the UCMH halo fraction. The smallest
detectable halo fraction, , is for . If gamma-ray emission from UCMHs is not detected, an
upper limit can be placed on the halo fraction. The bound is tightest, , for . The
resulting upper limit on the power spectrum of the primordial curvature
perturbation in the event of non-detection is in the range on scales . This is substantially tighter than the existing constraints from
primordial black hole formation on these scales, however it assumes that dark
matter is in the form of WIMPs and UCMHs are not disrupted during the formation
of the Milky Way halo.Comment: 5 pages, 2 figures, version to appear in Phys. Rev. D, minor change
Analisis Perubahan Penggunaan Lahan Sawah Menjadi Permukiman di Kabupaten Pringsewu Tahun 2012-2014
The purpose of this research was to acknowledge the changing of rice fields land use in Pringsewu Regency and the direction pattern change of rice-fields in Pringsewu. The research used the overlay method. The object of the research was rice fields which data turn into settlement. Data collection in research used observation, interviews and documentation method from associated agencies. Analysis of data used in this research was overlay. Results in this study were: 1 . In 2012-2014 in Pringsewu Regency there is a massive change of rice fields with 515,74ha turn to be settlement. 2 Patterns and distribution of rice field land change in Pringsewu to be settlements was greatest happened in Pringsewu subdistrict as a center of government, in Gadingrejo, Pagelaran, Sukoharjo which was leading to the north, central and eastern. There are three subdistricts which are not experienced the land change of rice fields, there are Adiluwih, Banyumas and Pardasuka subdistrict.Tujuan penelitian ini untuk mengetahui Perubahan penggunaan lahan sawah di Kabupaten Pringsewu dan pola arah Perubahan lahan sawah di Kabupaten Pringsewu. Penelitian ini menggunakan metode overlay. Objek dalam penelitian ini adalah lahan sawah yang berubah menjadi permukiman. Pengumpulan data dalam penelitian mengggunakan metode observasi, metode wawancara dan metode dokumentasi data dari dinas-dinas terkait. Analisis data yang digunakan dalam penelitian ini adalah cara overlay. Hasil dalam penelitian ini: 1. Pada tahun 2012-2014 diKabupaten Pringsewu terjadi Perubahan lahan sawah seluas 515,74ha menjadi permukiman. 2. Pola dan sebaran Perubahan lahan sawah menjadi permukiman di Kabupaten Pringsewu paling banyak terjadi dan berpusat di Kecamatan Pringsewu sebagai pusat pemerintahan, Kecamatan Gadingrejo, Kecamatan Pagelaran, Kecamatan Sukoharjo yang mengarah ke utara, tengah dan timur. Terdapat tiga Kecamatan yang tidak mengalami alih fungsi lahan sawah, yaitu Kecamatan Adiluwih, Banyumas dan Pardasuka
The Cramer-Rao bound and DMT signal optimisation for the identification of a Wiener-type model
MMTV-PyMT and derived Met-1 mouse mammary tumor cells as models for studying the role of the androgen receptor in triple-negative breast cancer progression
Triple-negative breast cancer (TNBC) has a faster rate of metastasis compared to other breast cancer subtypes and no effective targeted therapies are currently FDA-approved. Recent data indicate that the androgen receptor (AR) promotes tumor survival and may serve as a potential therapeutic target in TNBC. Studies of AR in disease progression and the systemic effects of anti-androgens have been hindered by the lack of an AR-positive (AR+) immunocompetent preclinical model. In this study we identified the transgenic MMTV-PyMT (mouse mammary tumor virus-polyoma middle tumor antigen) mouse mammary gland carcinoma model of breast cancer and Met-1 cells derived from this model as tools to study the role of AR in breast cancer progression. AR protein expression was examined in late-stage primary tumors and lung metastases from MMTV-PyMT mice as well as in Met-1 cells by immunohistochemistry (IHC). Sensitivity of Met-1 cells to the AR agonist dihydrotestosterone (DHT) and anti-androgen therapy was examined using cell viability, migration/invasion, and anchorage-independent growth assays. Late-stage primary tumors and lung metastases from MMTV-PyMT mice and Met-1 cells expressed abundant nuclear AR protein, while negative for estrogen and progesterone receptors. Met-1 sensitivity to DHT and AR antagonists demonstrated a reliance on AR for survival, and AR antagonists inhibited invasion and anchorage-independent growth. These data suggest that the MMTV-PyMT model and Met-1 cells may serve as valuable tools for mechanistic studies of the role of AR in disease progression and how anti-androgens affect the tumor microenvironment
Generalised constraints on the curvature perturbation from primordial black holes
Primordial black holes (PBHs) can form in the early Universe via the collapse
of large density perturbations. There are tight constraints on the abundance of
PBHs formed due to their gravitational effects and the consequences of their
evaporation. These abundance constraints can be used to constrain the
primordial power spectrum, and hence models of inflation, on scales far smaller
than those probed by cosmological observations. We compile, and where relevant
update, the constraints on the abundance of PBHs before calculating the
constraints on the curvature perturbation, taking into account the growth of
density perturbations prior to horizon entry. We consider two simple
parameterizations of the curvature perturbation spectrum on the scale of
interest: constant and power-law. The constraints from PBHs on the amplitude of
the power spectrum are typically in the range 10^{-2}-10^{-1} with some scale
dependence.Comment: 10 pages, 2 figures, version to appear in Phys. Rev. D with minor
change to calculation of constraints for spectral index not equal to on
Primordial Black Holes: sirens of the early Universe
Primordial Black Holes (PBHs) are, typically light, black holes which can
form in the early Universe. There are a number of formation mechanisms,
including the collapse of large density perturbations, cosmic string loops and
bubble collisions. The number of PBHs formed is tightly constrained by the
consequences of their evaporation and their lensing and dynamical effects.
Therefore PBHs are a powerful probe of the physics of the early Universe, in
particular models of inflation. They are also a potential cold dark matter
candidate.Comment: 21 pages. To be published in "Quantum Aspects of Black Holes", ed. X.
Calmet (Springer, 2014
Structural and Functional Characteristics of Color Vision Changes in Choroideremia
Color vision is considered a marker of cone function and its assessment in patients with retinal pathology is complementary to the assessments of spatial vision [best-corrected visual acuity (BCVA)] and contrast detection (perimetry). Rod-cone and chorioretinal dystrophies—such as choroideremia—typically cause alterations to color vision, making its assessment a potential outcome measure in clinical trials. However, clinical evaluation of color vision may be compromised by pathological changes to spatial vision and the visual field. The low vision Cambridge Color Test (lvCCT) was developed specifically to address these latter issues. We used the trivector version of the lvCCT to quantify color discrimination in a cohort of 53 patients with choroideremia. This test enables rapid and precise characterization of color discrimination along protan, deutan, and tritan axes more reliably than the historically preferred test for clinical trials, namely the Farnsworth Munsell 100 Hue test. The lvCCT demonstrates that color vision defects—particularly along the tritan axis—are seen early in choroideremia, and that this occurs independent of changes in visual acuity, pattern electroretinography and ellipsoid zone area on optical coherence tomography (OCT). We argue that the selective loss of tritan color discrimination can be explained by our current understanding of the machinery of color vision and the pathophysiology of choroideremia
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