Neutral buoyancy test evaluation of hardware and extravehicular activity procedures for on-orbit assembly of a 14 meter precision reflector

A procedure that enables astronauts in extravehicular activity (EVA) to perform efficient on-orbit assembly of large paraboloidal precision reflectors is presented. The procedure and associated hardware are verified in simulated Og (neutral buoyancy) assembly tests of a 14 m diameter precision reflector mockup. The test article represents a precision reflector having a reflective surface which is segmented into 37 individual panels. The panels are supported on a doubly curved tetrahedral truss consisting of 315 struts. The entire truss and seven reflector panels were assembled in three hours and seven minutes by two pressure-suited test subjects. The average time to attach a panel was two minutes and three seconds. These efficient assembly times were achieved because all hardware and assembly procedures were designed to be compatible with EVA assembly capabilities

The Precarious State of Family Balance Sheets

This report seeks to develop a clear picture of the current state of household financial security. It begins by exploring three components of family balance sheets -- income, expenditures, and wealth -- and how they have changed over the past several decades, and concludes with an examination of how these pieces interrelate and why understanding family finances requires that they be examined holistically. The data tell a powerful story about the state of household economic security and opportunity: Despite the national recovery, most families feel vulnerable and stressed, and could not withstand a serious financial emergency. This reality must begin to change if the American Dream is to remain alive and well for future generations

Leon Arnold Weintrob - (15/05/1932-16/02/2007)

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The versatility of a truss mounted mobile transporter for in-space construction

The Mobile Transporter (MT) evolution from early erectable structures assembly activities is detailed. The MT operational features which are required to support astronauts performing on-orbit structure construction or spacecraft assembly functions are presented and discussed. Use of the MT to perform a variety of assembly functions is presented. Estimated EVA assembly times for a precision segmented reflector approximately 20 m in diameter are presented. The EVA/MT technique under study for construction of the reflector (and the entire spacecraft) is illustrated. Finally, the current status of development activities and test results involving the MT and Space Station structural assembly are presented

Neighborhood Poverty and Household Financial Security

In a previous study, The Pew Charitable Trusts examined the effects of neighborhood context on American families' economic mobility. That analysis found that neighborhood poverty is associated with downward mobility, reinforcing other research that has shown a link between high-poverty neighborhoods and unemployment, poorer performing schools, and increased violence, all of which pose risks to residents' economic security.This chartbook draws on data from the Survey of American Family Finances, commissioned by Pew in November 2014, to illustrate the health of family balance sheets in high- and low-poverty communities across the United States and to examine how neighborhood context influences people's attitudes toward the economy

Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected

The Power-Sharing Event Dataset (PSED): a new dataset on the promises and practices of power-sharing in post-conflict countries

Past research on the relationship between power-sharing arrangements and the recurrence of civil conflict has primarily analyzed the promises of power-sharing stipulated in peace agreements. What happens afterwards, however, has not yet been sufficiently explored. This represents a major research gap, as the actual practices of power-sharing in post-conflict countries are likely to be influential in the possibility of civil conflict recurring. To address this shortcoming, we present a new global dataset on the promises and practices of power-sharing between the government of a state and former rebels in post-conflict countries. The collected data captures if, when and how power-sharing institutions have been promised and/or put into place, and whether they have subsequently been modified or abolished. The dataset encompasses every peace agreement signed after the cessation of a civil conflict in the years between 1989 and 2006, and covers a five-year period after the signature of each of these agreements (unless violence recurred earlier). The unit of analysis is the government–rebel dyad during the post-conflict period and data is recorded in an event data format. A first analysis of the Power-Sharing Event Dataset (PSED) reveals that the effects of the promises of power-sharing on civil conflict recurrence follow a different logic than the effects of their practices. This finding emphasizes the necessity for in-depth analyses of post-conflict situations for which the PSED provides the necessary data

Somatic gene therapy for cancer. The utility of transferrinfection in generating ‘tumor vaccines’

The last few years have seen the development of a branch of somatic gene therapy which aims at strengthening the immune surveillance of the body, leading to eradication of disseminated cancer tumor cells and occult micrometastases after surgical removal of the primary tumor. Such a tumor vaccination protocol calls for cultivation of the primary tumor tissue and the insertion of one of three types of genes into the isolated cultured tumor cells followed by irradiation of the transfected or transduced cells to render them incapable of further proliferation. The cells so treated constitute the ‘tumor vaccine’. A review of the literature suggests that for mouse models, in the initial period after inoculation, rejection of the tumor cells is usually effected by non-T-cell immunity, whereas the long-term systemic immune response is based on cytotoxic T-cells. High expression of the gene inserted into the tumor cells may be critical for the success of the vaccination procedure. Examples are given which indicate that transferrinfection, a procedure to introduce genes by adenovirus-augmented receptor-mediated endocytosis, meets some important prerequisites for successful application of this type of gene therapy

The Complex Story of American Debt

This report explores a key element of wealth: household debt. Debt is sometimes acquired for mobility-enhancing purposes, such as to pay for college or purchase a home. But debt can also serve as a stopgap for families to cover regular expenses or deal with financial emergencies, especially if their savings are not sufficient. The type and amount of debt that households carry contribute to their wealth and their overall financial health