33 research outputs found
Cosmology with anisotropic galaxy clustering from the combination of power spectrum and bispectrum
The apparent anisotropies of the galaxy clustering in observable redshift
space provide a unique opportunity to simultaneously probe cosmic expansion and
gravity on cosmological scales via the Alcock--Paczynski effect and
redshift-space distortions. While the improved theoretical models have been
proposed and developed to describe the apparent anisotropic clustering at
weakly non-linear scales, the applicability of these models is still limited in
the presence of the non--perturbative smearing effect caused by the randomness
of the relative velocities. Although the cosmological constraint from the
anisotropic clustering will be certainly improved with a more elaborate
theoretical model, we here consider an alternative way by using the statistical
power of both the power spectrum and bispectrum at large scales. Based on the
Fisher matrix analysis, we estimate the benefit of combining the power spectra
and bispectra, finding that the constraints on the cosmic expansion and growth
of structure will be improved by a factor of two. This compensates for the loss
of constraining power using the power spectrum alone due to the randomness of
the relative velocities.Comment: 11 pages, 8 figures, preprint number YITP-15-
Beyond consistency test of gravity with redshift-space distortions at quasi-linear scales
Redshift-space distortions (RSD) offer an attractive method to measure the
growth of cosmic structure on large scales, and combining with the measurement
of the cosmic expansion history, it can be used as cosmological tests of
gravity. With the advent of future galaxy redshift surveys aiming at precisely
measuring the RSD, an accurate modeling of RSD going beyond linear theory is a
critical issue in order to detect or disprove small deviations from general
relativity (GR). While several improved models of RSD have been recently
proposed based on the perturbation theory (PT), the framework of these models
heavily relies on GR. Here, we put forward a new PT prescription for RSD in
general modified gravity models. As a specific application, we present
theoretical predictions of the redshift-space power spectra in f(R) gravity
model, and compare them with N-body simulations. Using the PT template that
takes into account the effects of both modifications of gravity and RSD
properly, we successfully recover the fiducial model parameter in N-body
simulations in an unbiased way. On the other hand, we found it difficult to
detect the scale dependence of the growth rate in a model-independent way based
on GR templates.Comment: 17 pages, 9 figures, version accepted for publication in PR
Simultaneous constraints on the growth of structure and cosmic expansion from the multipole power spectra of the SDSS DR7 LRG sample
The anisotropic galaxy clustering on large scales provides us with a unique
opportunity to probe into the gravity theory through the redshift-space
distortions (RSDs) and the Alcock-Paczynski effect. Using the multipole power
spectra up to hexadecapole (ell=4), of the Luminous Red Galaxy (LRG) sample in
the data release 7 (DR7) of the Sloan Digital Sky Survey II (SDSS-II), we
obtain simultaneous constraints on the linear growth rate f, angular diameter
distance D_A, and Hubble parameter H at redshift z = 0.3. For this purpose, we
first extensively examine the validity of a theoretical model for the
non-linear RSDs using mock subhalo catalogues from N-body simulations, which
are constructed to match with the observed multipole power spectra. We show
that the input cosmological parameters of the simulations can be recovered well
within the error bars by comparing the multipole power spectra of our
theoretical model and those of the mock subhalo catalogues. We also carefully
examine systematic uncertainties in our analysis by testing the dependence on
prior assumption of the theoretical model and the range of wavenumbers to be
used in the fitting. These investigations validate that the theoretical model
can be safely applied to the real data. Thus, our results from the SDSS DR7 LRG
sample are robust including systematics of theoretical modeling; f(z = 0.3)
sigma_8(z = 0.3) =0.49+-0.08(stat.)+-0.04(sys.), D_A (z = 0.3)
=968+-42(stat.)+-17(sys.)[Mpc], H (z = 0.3)
=81.7+-5.0(stat.)+-3.7(sys.)[km/s/Mpc]. We believe that our method to constrain
the cosmological parameters using subhaloes catalogues will be useful for more
refined samples like CMASS and LOWZ catalogues in the Baryon Oscillation
Spectroscopic Survey in SDSS-III.Comment: accepted for publication in MNRA
The Japanese space gravitational wave antenna; DECIGO
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future
Japanese space gravitational wave antenna. DECIGO is expected to open a new window of
observation for gravitational wave astronomy especially between 0.1 Hz and 10 Hz, revealing
various mysteries of the universe such as dark energy, formation mechanism of supermassive
black holes, and inflation of the universe. The pre-conceptual design of DECIGO consists of
three drag-free spacecraft, whose relative displacements are measured by a differential Fabry–
Perot Michelson interferometer. We plan to launch two missions, DECIGO pathfinder and pre-
DECIGO first and finally DECIGO in 2024
Beyond consistency test of gravity with redshift-space distortions at quasilinear scales
Low Energy Intake Diagnosed Using the Harris–Benedict Equation Is Associated with Poor Prognosis in Elderly Heart Failure Patients
Introduction: Insufficient nutrient intake is a strong independent predictor of mortality in elderly patients with heart failure. However, it is unclear to what extent energy intake affects their prognosis. This study investigated the association between patient outcomes and actual measured energy intake in elderly patients (≥65 years) with heart failure. Methods: This study enrolled 139 elderly patients who were hospitalized with worsening heart failure at Shingu Municipal Medical Center, Shingu, Japan, between May 2017 and April 2018. Energy intake was evaluated for three days (from three days prior to the day of discharge until the day of discharge). Based on basal energy expenditure calculated using the Harris–Benedict equation, the patients were classified into a low-energy group (n = 38) and a high-energy group (n = 101). We assessed the prognosis in terms of both all-cause mortality and readmission due to worsening heart failure as a primary outcome. Results: Compared to the patients in the high-energy group, the patients in the low-energy group were predominantly female, less frequently had smoking habits and ischemic heart diseases, and had a higher left ventricular ejection fraction. The low-energy group had higher mortality than the high-energy group (p = 0.028), although the two groups showed equivalent event rates of the primary outcome (p = 0.569). Conclusion: Calculations based on the Harris–Benedict equation revealed no significant difference in the primary outcome between the two groups, with a secondary outcome that showed worse mortality in the low-energy group. Given this result, energy requirement-based assessments using the Harris–Benedict equation might help in the management of elderly heart failure patients in terms of improved life outcomes
Violent recidivism among mentally disordered offenders in Japan
BACKGROUND:
A new forensic mental health law was enacted in Japan in 2003, enabling development of specialist services. Before their establishment, it is important to determine the nature, frequency and correlates of the problems they are designed to ameliorate.
AIMS:
To establish rates of violent recidivism among mentally disordered offenders before the new legislation, and examine associated risk factors.
METHOD:
Data were extracted from one complete annual (1980) national cohort of people judged by the Court or prosecutor to be without responsibility for a criminal offence, or of sufficiently diminished responsibility for it to be diverted for psychiatric treatment. The outcome measure was violent recidivism after community discharge and before 1991.
RESULTS:
Fifty-two (10%) of 489 in the cohort were arrested or convicted of further violent offences. Violent recidivism was most strongly associated with a substance-related disorder, but histories of violence, homelessness and short index admissions were independently related.
CONCLUSIONS:
Violent recidivism was so unusual that, on this outcome, it could take many years to show any effect of the new service. Desistance from substance use, compliance with treatment and maintenance of stable housing may be better indicators of success, and their achievement a good preventive strategy