Spherical Redshift Distortions

Peculiar velocities induce apparent line of sight displacements of galaxies in redshift space, distorting the pattern of clustering in the radial versus transverse directions. On large scales, the amplitude of the distortion yields a measure of the dimensionless linear growth rate $\beta \approx \Omega^{0.6}/b$, where $\Omega$ is the cosmological density and $b$ the linear bias factor. To make the maximum statistical use of the data in a wide angle redshift survey, and for the greatest accuracy, the spherical character of the distortion needs to be treated properly, rather than in the simpler plane parallel approximation. In the linear regime, the redshift space correlation function is described by a spherical distortion operator acting on the true correlation function. It is pointed out here that there exists an operator, which is essentially the logarithmic derivative with respect to pair separation, which both commutes with the spherical distortion operator, and at the same time defines a characteristic scale of separation. The correlation function can be expanded in eigenfunctions of this operator, and these eigenfunctions are eigenfunctions of the distortion operator. Ratios of the observed amplitudes of the eigenfunctions yield measures of the linear growth rate $\beta$ in a manner independent of the shape of the correlation function. More generally, the logarithmic derivative $\partial/\partial\ln r$ with respect to depth $r$, along with the square $L^2$ and component $L_z$ of the angular momentum operator, form a complete set of commuting operators for the spherical distortion operator acting on the density. The eigenfunctions of this complete set of operators are spherical waves about the observer, with radial part lying in logarithmic real or Fourier space.Comment: 15 pages, with 1 embedded EPS figur

The Differential Impacts of Federally Assisted Housing Programs on Nearby Property Values: A Philadelphia Case Study

Prior research has found negative impacts of public housing on neighborhood quality. Few studies have examined the impact of public and other assisted housing programs on real estate prices, particularly differential impact by program type. In this study, federally assisted housing units by program type are aggregated by 1/8- or 1/4-mile radii around individual property sales and regressed on sales prices from 1989 through 1991, controlling for area demographic, housing, and amenity variables. Results show that public housing developments exert a modest negative impact on property values. Scattered-site public housing and units rented with Section 8 certificates and vouchers have slight negative impacts. Federal Housing Administration–assisted units, public housing homeownership program units, and Section 8 New Construction and Rehabilitation units have modest positive impacts. Low-Income Housing Tax Credit sites have a slight negative effect. Results suggest that homeownership programs and new construction/rehabilitation programs have a more positive impact on property values

Prevalence of Treated Behavioral Disorders among Adult Shelter Users: A Longitudinal Study

Of 27,638 homeless adults admitted to Philadelphia public shelters in the years 1990 through 1992, 20.1% received treatment for a mental health disorder, and 25.3% for a substance use disorder in the years 1985 through 1993. An additional 20.7% were identified as having untreated substance use problems. Overall, a total of 65.5% of adult shelter users were identified as ever having had a mental health or substance use problem, treated or untreated

The Treated Prevalence of Mental Health and Substance Use Disorders among Adults Admitted to the Philadelphia Shelter System: Results from the Integration of Longitudinal Data on Shelter and Mental Health Services Utilization

This paper reports results from a study of the treated prevalence of mental health and substance use disorders among adults admitted to Philadelphia public shelters between 1990 and 1992 (N=28,638). Identifiers and service records from longitudinal databases on shelter and mental health services were merged, finding that 49% of single homeless adults and 33.2% of homeless adults with children had a treatment for a mental health or substance use disorder between 1985 and 1993. The rate of treatment for serious mental illness (SMI) was 10.7% (by most frequently occurring diagnosis). Single women (18.6%) had twice the rate of SMI as single men (9.9%), and single adults (12.1%) had twice the rate of SMI as adults with children (6.2%). The treatment rate of substance use disorders (25.2%) was higher than the rate of mental health disorders (20%), and was twice as high for single adults (28.6%) as for adults with children (14.6%). An additional 20% of adult shelter users were identified through shelter records as having untreated substance use problems. Veterans had comparable rates of disorders as nonveterans. Overall, 65% of adult shelter users were identified as ever having some mental health or substance use problem, treated or untreated. People with SMI were less represented among shelter users on two single day censuses than over three years, suggesting a higher rate of turnover among people with SMI, while people with substance use disorders were overrepresented by a third on the two single day censuses, suggesting a lower rate of turnover among people treated for substance abuse. Of the treated Medicaid population, 6.8% became homeless in the three year study period, representing 7.8% of the treated population with SMI, 9.5% of the treated schizophrenia population, and 20.1% of the population receiving inpatient substance abuse services. Approximately 3,000 people with SMI became homeless in the 3-year study period, with an average of 73 people with SMI entering shelter for the first time each month. An analysis of inpatient usage found that 25.7% of the SMI and 34.2% of the treated substance abuse population were hospitalized within 120 days of their first shelter admission (before or after). Fourteen percent of the SMI were also seen in an emergency room within 120 days of shelter admission (before or after)

Dynamics and plasma properties of an X-ray jet from SUMER, EIS, XRT and EUVI A & B simultaneous observations

Small-scale transient phenomena in the quiet Sun are believed to play an important role in coronal heating and solar wind generation. One of them named as "X-ray jet" is the subject of our study. We indent to investigate the dynamics, evolution and physical properties of this phenomenon. We combine spatially and temporally multi-instrument observations obtained simultaneously with the SUMER spectrometer onboard SoHO, EIS and XRT onboard Hinode, and EUVI/SECCHI onboard the Ahead and Behind STEREO spacecrafts. We derive plasma parameters such as temperatures and densities as well as dynamics by using spectral lines formed in the temperature range from 10 000 K to 12 MK. We also use image difference technique to investigate the evolution of the complex structure of the studied phenomenon. With the available unique combination of data we were able to establish that the formation of a jet-like event is triggered by not one but several energy depositions which are most probably originating from magnetic reconnection. Each energy deposition is followed by the expulsion of pre-existing or new reconnected loops and/or collimated flow along open magnetic field lines. We derived in great detail the dynamic process of X-ray jet formation and evolution. We also found for the first time spectroscopically in the quiet Sun a temperature of 12~MK and density of 4 10^10~cm^-3 in a reconnection site. We raise an issue concerning an uncertainty in using the SUMER Mg X 624.9 A line for coronal diagnostics. We clearly identified two types of up-flow: one collimated up-flow along open magnetic field lines and a plasma cloud formed from the expelled BP loops. We also report a cooler down-flow along closed magnetic field lines. A comparison is made with a model developed by Moreno-Insertis \etal\ (2008).Comment: 15 pages, 15 figure

Where the Homeless Come From: A Study of the Prior Address Distribution of Families Admitted to Public Shelters in New York City and Philadelphia

This study investigates hypotheses regarding the association of census tract variables with the risk for homelessness. We used prior address information reported by families entering emergency shelters in two large U.S. cities to characterize the nature of that distribution. Three dense clusters of homeless origins were found in Philadelphia and three in New York City, accounting for 67 percent and 61 percent of shelter admissions and revealing that homeless families’ prior addresses are more highly concentrated than the poverty distribution in both cities. The rate of shelter admission is strongly and positively related to the concentration of poor, African-American, and female-headed households with young children in a neighborhood. It is also correlated with fewer youth, elderly, and immigrants. Such areas have higher rates of unemployment and labor force nonparticipation, more housing crowding, more abandonment, higher rates of vacancy, and higher rent-to-income ratios than other areas

How Can Active Region Plasma Escape into the Solar Wind from below a Closed Helmet Streamer?

Recent studies show that active-region (AR) upflowing plasma, observed by the EUV-Imaging Spectrometer (EIS), onboard Hinode, can gain access to open field-lines and be released into the solar wind (SW) via magnetic-interchange reconnection at magnetic null-points in pseudo-streamer configurations. When only one bipolar AR is present on the Sun and it is fully covered by the separatrix of a streamer, such as AR 10978 in December 2007, it seems unlikely that the upflowing AR plasma can find its way into the slow SW. However, signatures of plasma with AR composition have been found at 1 AU by Culhane et al. (2014) apparently originating from the West of AR 10978. We present a detailed topology analysis of AR 10978 and the surrounding large-scale corona based on a potential-field source-surface (PFSS) model. Our study shows that it is possible for the AR plasma to get around the streamer separatrix and be released into the SW via magnetic reconnection, occurring in at least two main steps. We analyse data from the Nan\c{c}ay Radioheliograph (NRH) searching for evidence of the chain of magnetic reconnections proposed. We find a noise storm above the AR and several varying sources at 150.9 MHz. Their locations suggest that they could be associated with particles accelerated during the first-step reconnection process and at a null point well outside of the AR. However, we find no evidence of the second-step reconnection in the radio data. Our results demonstrate that even when it appears highly improbable for the AR plasma to reach the SW, indirect channels involving a sequence of reconnections can make it possible.Comment: 26 pages, 10 figures. appears in Solar Physics, 201

What is the true nature of blinkers?

Aims. The aim of this work is to identify the true nature of the transient EUV brightenings, called blinkers. Methods. Co-spatial and co-temporal multi-instrument data, including imaging (EUVI/STEREO, XRT and SOT/Hinode), spectroscopic (CDS/SoHO and EIS/Hinode) and magnetogram (SOT/Hinode) data, of an isolated equatorial coronal hole were used. An automatic program for identifying transient brightenings in CDS O v 629 Å, EUVI 171 Å and XRT was applied. Results. We identified 28 blinker groups in the CDS O v 629 Å raster images. All CDS O v 629 Å blinkers showed counterparts in EUVI 171 Å and 304 Å images. We classified these blinkers into two categories, one associated with coronal counterparts and other with no coronal counterparts as seen in XRT images and EIS Fe xii 195.12 Å raster images. Around two-thirds of the blinkers show coronal counterparts and correspond to various events like EUV/X-ray jets, brightenings in coronal bright points or foot-point brightenings of larger loops. These brightenings occur repetitively and have a lifetime of around 40 min at transition region temperatures. The remaining blinker groups with no coronal counterpart in XRT and EIS Fe xii 195.12 Å appear as point-like brightenings and have chromospheric/transition region origin. They take place only once and have a lifetime of around 20 min. In general, lifetimes of blinkers are different at different wavelengths, i.e. different temperatures, decreasing from the chromosphere to the corona. Conclusions. This work shows that the term blinker covers a range of phenomena. Blinkers are the EUV response of various transient events originating at coronal, transition region and chromospheric heights. Hence, events associated with blinkers contribute to the formation and maintenance of the temperature gradient in the transition region and the corona

The Impact of Welfare Reform on Public Shelter Utilization in Philadelphia: A Time-Series Analysis

The use of public shelters in Philadelphia was examined both before and after the implementation of Act 35, Pennsylvania’s response to the Personal Responsibility and Work Opportunity Reconciliation Act of 1996. Univariate interrupted time-series analyses were conducted to determine if trends in shelter utilization (the number of families admitted, by family size, by race, by age of household head, by income, by disability indicator, and by average length of stay) changed significantly after March 1997, the month in which Act 35 was implemented, or after 3, 6, 9, and 12 months of implementation. Results indicate that family size and household head age increased after the implementation of Temporary Assistance for Needy Families, although not at consistent lags. A small negative effect on self-reported substance abuse and a small positive effect on the proportion of household heads with a disability were found, but at inconsistent lags. As is the case with most evaluations of welfare reform, it is difficult to separate the effects of welfare reform and Philadelphia\u27s economy during the study period. To test the effect of Act 35\u27s implementation while controlling for economic factors, a multivariate regression analysis of family shelter admissions was conducted along with variables for the unemployment rate and for the consumer price index for the cost of rental housing. This analysis revealed a significant positive effect of unemployment and housing costs on public shelter admissions among families and no effect of the implementation of welfare reform