Lyman H. Legters, ed.: The German Democratic Republic: A Developed Socialist Society

Boulder, Colo.: Westview, 1978. (Westview Special Studies on the Soviet Union and Eastern Europe), xi and 285 p

Limb-darkening functions as derived from along-track operation of the ERBE scanning radiometer for January 1985

During January 1985, the scanning radiometer aboard the Earth Radiation Budget Satellite was operated to scan along-track. These data have been analyzed to produce limb-darkening functions for Earth emitted radiation, which relate the radiance in any given direction to the radiant exitance. Limb-darkening functions are presented in tabular form and shown as figures for 10 day cases and 12 night cases, corresponding to various scene types and latitude zones. The scene types were computed using measurements within 10 deg of zenith. The limb-darkening functions have values of 1.03 to 1.09 at zenith, with 1.06 being typical. It is found that latitude causes a variation on the order of 1 percent, except for zenith angles greater than 70 deg. These limb-darkening models are about 2 percent higher at zenith than the models derived from Nimbus 7 data

Traffic-adaptive, flow-specific medium access for wireless networks

In this report, we formally introduce the novel concept of traffic-adaptive, flow-specific medium access control and show that it outperforms contention, non-contention and hybrid medium access schemes. A traffic-adaptive, flow-specific mechanism is proposed that utilizes flow-specific queue size statistics to select between medium access modes. A general model for traffic adaptive, flow-specific medium access control is developed and it is shown that hybrid medium access as well as traditional contention-based and non-contention schemes can be seen as special cases of the more general flow-specific access. The two flow, two-mode case of the general model is developed in detail and it is shown analytically that this queue-based implementation of traffic-adaptive, flow-specific medium access outperforms contention, non-contention, and hybrid approaches. The proposed traffic-adaptive, flow-specific mechanism is applied to Cooperative Wireless Sensor Network Medium Access Control (CWS-MAC) a flow-specific medium access protocol. Performance is evaluated is evaluated and compared to the traditional medium access approaches. Both analytical and simulation results are provided including the development of throughput and delay expressions for slotted ALOHA with periodic server vacations.Approved for public release; distribution is unlimited

Energy-efficient, Flow-specific Medium Access using Preamble Sampling

Current wireless sensor network applications face challenging power constraints that demand low duty cycles. In this paper, we propose an energy-efficient, flow-specific medium access scheme that is capable of achieving low duty cycles while taking advantage of the performance improvements available through a flow-specific medium access approach. The scheme is based on an adaptive sleep and wake cycle that responds to changes in both contention and non-contention traffic loads through the use of preamble sampling. A preamble sampling probability parameter is introduced to manage the trade-off between energy efficiency and network throughput and delay performance. A performance analysis is conducted and verified through simulation

Replacing Members with Managers? Mutualism among Membership and Nonmembership Advocacy Organizations in the United States

Associations with a professional staff but no members (nonmembership advocacy organizations, or NMAOs) are the subject of lively debate. Many argue that their proliferation has allowed an expansion of advocacy without an accompanying growth in civic engagement. This article asks if there has been significant recent growth of NMAOs and if those organizations have displaced membership advocacy organizations (MAOs). The authors find no evidence for a proportional increase of NMAOs since the 1960s. Further, among all organizations in three populationspeace, women's issues, and human rightsNMAOs have not displaced MAOs. In particular, the authors find that MAO density shapes NMAO founding, as membership groups provide a base for professional advocacy. These findings challenge the notion that U.S. civic life has undergone a systemic transformation away from organizational forms that promote civic engagement

Lineage tracing of Foxd1-expressing embryonic progenitors to assess the role of divergent embryonic lineages on adult dermal fibroblast function

Recent studies have highlighted the functional diversity of dermal fibroblast populations in health and disease, with part of this diversity linked to fibroblast lineage and embryonic origin. Fibroblasts derived from foxd1-expressing progenitors contribute to the myofibroblast populations present in lung and kidney fibrosis in mice but have not been investigated in the context of dermal wound repair. Using a Cre/Lox system to genetically track populations derived from foxd1-expressing progenitors, lineage-positive fibroblasts were identified as a subset of the dermal fibroblast population. During development, lineage-positive cells were most abundant within the dorsal embryonic tissues, contributing to the developing dermal fibroblast population, and remaining in this niche into adulthood. In adult mice, assessment of fibrosis-related gene expression in lineage-positive and lineage-negative populations isolated from wounded and unwounded dorsal skin was performed, identifying an enrichment of transcripts associated with matrix synthesis and remodeling in the lineage-positive populations. Using a novel excisional wound model, ventral skin healed with a greatly reduced frequency of foxd1 lineage-positive cells. This work supports that the embryonic origin of fibroblasts is an important predictor of fibroblast function, but also highlights that within disparate regions, fibroblasts of different lineages likely undergo convergent differentiation contributing to phenotypic similarities

Recommended Practice for Pressure Measurements and Calculation of Effective Pumping Speeds During Electric Propulsion Testing

The electric propulsion community has been implored to establish and implement a set of universally applicable test standards during the research, development, and qualification of electric propulsion systems. Variability between facility-to-facility and more importantly ground-to-flight performance can result in large margins in application or aversion to mission infusion. Performance measurements and life testing under appropriate conditions can be costly and lengthy. Measurement practices must be consistent, accurate, and repeatable. Additionally, the measurements must be universally transportable across facilities throughout the development, qualification, spacecraft integration, and on-orbit performance. A recommended practice for making pressure measurements, pressure diagnostics, and calculating effective pumping speeds with justification is presented

Plans for a 10-m Submillimeter-wave Telescope at the South Pole

A 10 meter diameter submillimeter-wave telescope has been proposed for the NSF Amundsen-Scott South Pole Station. Current evidence indicates that the South Pole is the best submillimeter-wave telescope site among all existing or proposed ground-based observatories. Proposed scientific programs place stringent requirements on the optical quality of the telescope design. In particular, reduction of the thermal background and offsets requires an off-axis, unblocked aperture, and the large field of view needed for survey observations requires shaped optics. This mix of design elements is well-suited for large scale (square degree) mapping of line and continuum radiation from submillimeter-wave sources at moderate spatial resolutions (4 to 60 arcsecond beam size) and high sensitivity (milliJansky flux density levels). the telescope will make arcminute angular scale, high frequency Cosmic Microwave Background measurements from the best possible ground-based site, using an aperture which is larger than is currently possible on orbital or airborne platforms. Effective use of this telescope will require development of large (1000 element) arrays of submillimeter detectors which are background-limited when illuminated by antenna temperatures near 50 K.Comment: 12 pages, 3 figure