Statistical Identification of XMM-Newton Sources Using XID Database

The XMM identification programme (XID) is accumulating Optical/IR images and spectra to identify thousands of XMM sources. The XID Database is the main repository of this data and permits easy selection and correlation of XMM X-ray and UV (from Optical Monitor) data with Optical/IR observations. Here we discuss the methodology and some preliminary results of statistical classification and identification of X-ray sources using the data from XID Database. We show that in the medium range of X-ray fluxes and optical/UV magnitudes most of XMM sources are AGNs in agreement with previous observations. Moreover, AGNs are mostly concentrated in a small area of (U/g-r)-HR2/HR3 plane. At present the confirmed identifications are too scarce to permit statistical identification of individual sources without taking their spectra. Nonetheless, these types of investigation help to better understand general characteristics of classes of astronomical objects in X-ray and its relation with optical/IR ones.Comment: 1 page, 1 figure, To be published in the proceedings of "International Workshop on X-Ray Surveys in the light of new observatories", Santander, Spain, 4-6 Sep. 200

Shifting the Burden of HIV/AIDS

As the economic burden of HIV/AIDS increases in sub-Saharan Africa, the allocation of the burden among levels and sectors of societies is changing. The private sector has greater scope than government, households, or NGOs to avoid the economic burden of AIDS, and a systematic shifting of the burden away from the private sector is underway. Common practices that shift the AIDS burden from businesses to households and government include pre-employment screening, reduced employee benefits, restructured employment contracts, outsourcing of less skilled jobs, selective retrenchments, and changes in production technologies. In South Africa, more than two thirds of large employers have reduced health care benefits or required larger contributions by employees. Most firms have replaced defined benefit retirement funds, which expose the firm to large annual costs but provide long-term support for families, with defined contribution funds, which eliminate firm risk but provide little to families of younger workers who die of AIDS. Contracting out of previously permanent jobs also shields firms from costs while leaving households and government to care for affected workers and their families. Many of these changes are responses to globalization and would have occurred in the absence of AIDS, but they are devastating for employees with HIV/AIDS. This paper argues that the shifting of the economic burden of AIDS is a predictable response by business to which a thoughtful public policy response is needed. Countries should make explicit decisions about each sector’s responsibilities if a socially desirable allocation is to be achieved

Shifting the Burden of HIV/AIDS

As the economic burden of HIV/AIDS increases in sub-Saharan Africa, the allocation of the burden among levels and sectors of societies is changing. The private sector has greater scope than government, households, or NGOs to avoid the economic burden of AIDS, and a systematic shifting of the burden away from the private sector is underway. Common practices that shift the AIDS burden from businesses to households and government include pre-employment screening, reduced employee benefits, restructured employment contracts, outsourcing of less skilled jobs, selective retrenchments, and changes in production technologies. In South Africa, more than two thirds of large employers have reduced health care benefits or required larger contributions by employees. Most firms have replaced defined benefit retirement funds, which expose the firm to large annual costs but provide long-term support for families, with defined contribution funds, which eliminate firm risk but provide little to families of younger workers who die of AIDS. Contracting out of previously permanent jobs also shields firms from costs while leaving households and government to care for affected workers and their families. Many of these changes are responses to globalization and would have occurred in the absence of AIDS, but they are devastating for employees with HIV/AIDS. This paper argues that the shifting of the economic burden of AIDS is a predictable response by business to which a thoughtful public policy response is needed. Countries should make explicit decisions about each sector’s responsibilities if a socially desirable allocation is to be achieved

Shifting the burden of HIV/AIDS

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers.As the economic burden of HIV/AIDS increases in sub-Saharan Africa, the allocation of the burden among levels and sectors of societies is changing. The private sector has greater scope than government, households, or NGOs to avoid the economic burden of AIDS, and a systematic shifting of the burden away from the private sector is underway. Common practices that shift the AIDS burden from businesses to households and government include pre-employment screening, reduced employee benefits, restructured employment contracts, outsourcing of less skilled jobs, selective retrenchments, and changes in production technologies. In South Africa, more than two thirds of large employers have reduced health care benefits or required larger contributions by employees. Most firms have replaced defined benefit retirement funds, which expose the firm to large annual costs but provide long-term support for families, with defined contribution funds, which eliminate firm risk but provide little to families of younger workers who die of AIDS. Contracting out of previously permanent jobs also shields firms from costs while leaving households and government to care for affected workers and their families. Many of these changes are responses to globalization and would have occurred in the absence of AIDS, but they are devastating for employees with HIV/AIDS. This paper argues that the shifting of the economic burden of AIDS is a predictable response by business to which a thoughtful public policy response is needed. Countries should make explicit decisions about each sector’s responsibilities if a socially desirable allocation is to be achieved

The private sector and HIV/AIDS in Africa: taking stock of six years of applied research

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers.BACKGROUND: Until recently, little was known about the costs of the HIV/AIDS epidemic to businesses in Africa and business responses to the epidemic. This paper synthesizes the results of a set of studies conducted between 1999 and 2006 and draws conclusions about the role of the private sector in Africa’s response to AIDS. METHODS: Detailed human resource, financial, and medical data were collected from 14 large private and parastatal companies in South Africa, Uganda, Kenya, Zambia, and Ethiopia. Surveys of small and medium-sized enterprises (SMEs) were conducted in South Africa, Kenya, and Zambia. Large companies’ responses or potential responses to the epidemic were investigated in South Africa, Uganda, Kenya, Zambia, and Rwanda. RESULTS: Among the large companies, estimated workforce HIV prevalence ranged from 5%- 37%. The average cost per employee lost to AIDS varied from 0.5-5.6 times the average annual compensation of the employee affected. Labor cost increases as a result of AIDS were estimated at anywhere from 0.6%-10.8% but exceeded 3% at only 2 of 14 companies. Treatment of eligible employees with ART at a cost of $360/patient/year was shown to have positive financial returns for most but not all companies. Uptake of employer-provided testing and treatment services varied widely. Among SMEs, HIV prevalence in the workforce was estimated at 10%-26%. SME managers consistently reported low AIDS related employee attrition, little concern about the impacts of AIDS on their companies, and relatively little interest in taking action, and fewer than half had ever discussed AIDS with their senior staff. AIDS was estimated to increase the average operating costs of small tourism companies in Zambia by less than 1%; labor cost increases in other sectors were probably smaller. CONCLUSIONS: Although there was wide variation among the firms studied, clear patterns emerged that will permit some prediction of impacts and responses in the future

Intersection bounds: estimation and inference

We develop a practical and novel method for inference on intersection bounds, namely bounds defined by either the infimum or supremum of a parametric or nonparametric function, or equivalently, the value of a linear programming problem with a potentially infinite constraint set. Our approach is especially convenient for models comprised of a continuum of inequalities that are separable in parameters, and also applies to models with inequalities that are non-separable in parameters. Since analog estimators for intersection bounds can be severely biased in finite samples, routinely underestimating the size of the identified set, we also offer a median-bias-corrected estimator of such bounds as a natural by-product of our inferential procedures. We develop theory for large sample inference based on the strong approximation of a sequence of series or kernel-based empirical processes by a sequence of "penultimate" Gaussian processes. These penultimate processes are generally not weakly convergent, and thus non-Donsker. Our theoretical results establish that we can nonetheless perform asymptotically valid inference based on these processes. Our construction also provides new adaptive inequality/moment selection methods. We provide conditions for the use of nonparametric kernel and series estimators, including a novel result that establishes strong approximation for any general series estimator admitting linearization, which may be of independent interest.

The Private Sector and HIV/AIDS in Africa: Taking Stock of Six Years of Applied Research

Background: Until recently, little was known about the costs of the HIV/AIDS epidemic to businesses in Africa and business responses to the epidemic. This paper synthesizes the results of a set of studies conducted between 1999 and 2006 and draws conclusions about the role of the private sector in Africa’s response to AIDS. Methods: Detailed human resource, financial, and medical data were collected from 14 large private and parastatal companies in South Africa, Uganda, Kenya, Zambia, and Ethiopia. Surveys of small and medium-sized enterprises (SMEs) were conducted in South Africa, Kenya, and Zambia. Large companies’ responses or potential responses to the epidemic were investigated in South Africa, Uganda, Kenya, Zambia, and Rwanda. Results: Among the large companies, estimated workforce HIV prevalence ranged from 5%¬37%. The average cost per employee lost to AIDS varied from 0.5-5.6 times the average annual compensation of the employee affected. Labor cost increases as a result of AIDS were estimated at anywhere from 0.6%-10.8% but exceeded 3% at only 2 of 14 companies. Treatment of eligible employees with ART at a cost of $360/patient/year was shown to have positive financial returns for most but not all companies. Uptake of employer-provided testing and treatment services varied widely. Among SMEs, HIV prevalence in the workforce was estimated at 10%-26%. SME managers consistently reported low AIDS-related employee attrition, little concern about the impacts of AIDS on their companies, and relatively little interest in taking action, and fewer than half had ever discussed AIDS with their senior staff. AIDS was estimated to increase the average operating costs of small tourism companies in Zambia by less than 1%; labor cost increases in other sectors were probably smaller. Conclusions: Although there was wide variation among the firms studied, clear patterns emerged that will permit some prediction of impacts and responses in the future

Rationing Antiretroviral Therapy for HIV/AIDS in Africa: Efficiency, Equity, and Reality

Background: Rationing of access to antiretroviral therapy already exists in sub-Saharan Africa and will intensify as national treatment programs develop. The number of people who are medically eligible for therapy will far exceed the human, infrastructural, and financial resources available, making rationing of public treatment services inevitable. Methods: We identified 15 criteria by which antiretroviral therapy could be rationed in African countries and analyzed the resulting rationing systems across 5 domains: clinical effectiveness, implementation feasibility, cost, economic efficiency, and social equity. Findings: Rationing can be explicit or implicit. Access to treatment can be explicitly targeted to priority subpopulations such as mothers of newborns, skilled workers, students, or poor people. Explicit conditions can also be set that cause differential access, such as residence in a designated geographic area, co-payment, access to testing, or a demonstrated commitment to adhere to therapy. Implicit rationing on the basis of first-come, first-served or queuing will arise when no explicit system is enforced; implicit systems almost always allow a high degree of queue-jumping by the elite. There is a direct tradeoff between economic efficiency and social equity. Interpretation: Rationing is inevitable in most countries for some period of time. Without deliberate social policy decisions, implicit rationing systems that are neither efficient nor equitable will prevail. Governments that make deliberate choices, and then explain and defend those choices to their constituencies, are more likely to achieve a socially desirable outcome from the large investments now being made than are those that allow queuing and queue-jumping to dominate

Intersection Bounds: estimation and inference

We develop a practical and novel method for inference on intersection bounds, namely bounds defined by either the infimum or supremum of a parametric or nonparametric function, or equivalently, the value of a linear programming problem with a potentially infinite constraint set. Our approach is especially convenient in models comprised of a continuum of inequalities that are separable in parameters, and also applies to models with inequalities that are non-separable in parameters. Since analog estimators for intersection bounds can be severely biased in finite samples, routinely underestimating the length of the identified set, we also offer a (downward/upward) median unbiased estimator of these (upper/lower) bounds as a natural by-product of our inferential procedure. Furthermore, our method appears to be the first and currently only method for inference in nonparametric models with a continuum of inequalities. We develop asymptotic theory for our method based on the strong approximation of a sequence of studentized empirical processes by a sequence of Gaussian or other pivotal processes. We provide conditions for the use of nonparametric kernel and series estimators, including a novel result that establishes strong approximation for general series estimators, which may be of independent interest. We illustrate the usefulness of our method with Monte Carlo experiments and an empirical example.

Why do Nigerian manufacturing firms take action on AIDS?

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers.OBJECTIVE: To identify differences between manufacturing firms in Nigeria that have undertaken HIV/AIDS prevention activities and those that have not as a step toward improving the targeting of HIV policies and interventions. METHODS: A survey of a representative sample of registered manufacturing firms in Nigeria, stratified by location, workforce size, and industrial sector. The survey was administered to managers of 232 firms representing most major industrial areas and sectors in March-April 2001. RESULTS: 45.3 percent of the firms’ managers received information about HIV/AIDS from a source outside the firm in 2000; 7.7 percent knew of an employee who was HIV-positive at the time of the survey; and 13.6 percent knew of an employee who had left the firm and/or died in service due to AIDS. Only 31.7 percent of firms took any action to prevent HIV among employees in 2000, and 23.9 percent had discussed the epidemic as a potential business concern. The best correlates of having taken action on HIV were knowledge of an HIV-positive employee or having lost an employee to AIDS (odds ratio [OR] 6.36, 95% confidence interval [CI]: 2.30, 17.57) and receiving information about the disease from an outside source (OR 7.83, 95% CI: 3.46, 17.69). CONCLUSIONS: Despite a nationwide HIV seroprevalence of 5.8 percent, as of 2001 most Nigerian manufacturing firm managers did not regard HIV/AIDS as a serious problem and had neither taken any action on it nor discussed it as a business issue. Providing managers with accurate, relevant information about the epidemic and practical prevention interventions might strengthen the business response to AIDS in countries like Nigeria