Results of NASA/Army transmission research

Since 1970 the NASA Lewis Research Center and the U.S. Army Aviation Systems Command have shared an interest in advancing the technology for helicopter propulsion systems. In particular, that portion of the program that applies to the drive train and its various mechanical components are outlined. The major goals of the program were (and continue to be) to increase the life, reliability, and maintainability, reduce the weight, noise, and vibration, and maintain the relatively high mechanical efficiency of the gear train. Major historical milestones are reviewed, significant advances in technology for bearings, gears, and transmissions are discussed, and the outlook for the future is presented. The reference list is comprehensive

Predictors of homelessness among families and single adults after exit from homelessness prevention and rapid re-housing programs: evidence from the Department of Veterans Affairs Supportive Services for Veteran Families Program

This article assesses the extent and predictors of homelessness among Veterans (both Veterans in families with children and single adults Veterans) exiting the Supportive Services for Veteran Families (SSVF) program, which is a nationwide homelessness prevention and rapid re-housing program geared primarily towards those experiencing crisis homelessness. Among rapid re-housing participants, 16% and 26% of single adult Veterans experienced an episode of homelessness at one and two years post-SSVF exit; the comparable figures at those follow-up times for Veterans in families were 9.4% and 15.5%, respectively. Relatively fewer single adult Veterans and Veterans in families receiving homelessness prevention services experienced an episode of homelessness at one and two years post-SSVF exit. Veteran-level characteristics, including age, gender, prior history of homelessness and recent engagement with VA healthcare were generally more salient predictors of homelessness following SSVF exit than variables measuring SSVF program factors, or community-level housing market conditions.U.S. Department of Veterans Affairs, National Center on Homelessness Among Veteran

Ascertainment bias for non-twin relatives in twin proband studies

Journal ArticleWhen families are ascertained through affected twins, as for example when twin probands are selected from a registry and their non-twin relatives studied, a correction for ascertainment bias is needed. It is shown that probandwise counting (where relatives of doubly ascertained twin pairs are counted twice) is the appropriate method. The bias resulting from pairwise counting is given and depends on the genetic model and on the probability of selecting an affected twin as a proband. For the multifactorial and generalized single major locus models the bias is small, and the problems associated with nonindependent ascertainment are negligible in practice

Results of a study of the stability of cointegrating relations comprised of broad monetary aggregates

There is strong evidence of a stable “money demand” relationship for MZM and M2 through the 1990s. Though the M2 relationship breaks down somewhere around 1990, evidence has been accumulating that the disturbance is well characterized as a permanent upward shift in M2 velocity that began around 1990 and was largely over by 1994. This paper’s results support the hypothesis that households permanently reallocated a portion of their wealth from time deposits to mutual funds. This reallocation may have been induced by depository restructuring, but it could also be explained by appropriately measured opportunity cost.Demand for money

Forming Early-type Galaxies in Groups Prior to Cluster Assembly

We study a unique proto-cluster of galaxies, the supergroup SG1120-1202. We quantify the degree to which morphological transformation of cluster galaxies occurs prior to cluster assembly in order to explain the observed early-type fractions in galaxy clusters at z=0. SG1120-1202 at z~0.37 is comprised of four gravitationally bound groups that are expected to coalesce into a single cluster by z=0. Using HST ACS observations, we compare the morphological fractions of the supergroup galaxies to those found in a range of environments. We find that the morphological fractions of early-type galaxies (~60 %) and the ratio of S0 to elliptical galaxies (0.5) in SG1120-1202 are very similar to clusters at comparable redshift, consistent with pre-processing in the group environment playing the dominant role in establishing the observed early-type fraction in galaxy clusters.Comment: 5 pages, 2 figures, 2 tables. Accepted for publication in ApJ Letter

Helicopter transmission research at NASA Lewis Research Center

A joint helicopter transmission research program between NASA Lewis Research Center and the U.S. Army Aviation Systems Command has existed since 1970. Program goals are to reduce weight and noise and to increase life and reliability. Reviewed are significant advances in technology for gears and transmissions and the experimental facilities at NASA Lewis for helicopter transmission testing are described. A description of each of the rigs is presented along with some significant results from the experiments

A Search for Young Stars in the S0 Galaxies of a Super-Group at z=0.37

We analyze Galaxy Evolution Explorer UV data for a system of four gravitationally bound groups at z = 0.37, SG1120, which is destined to merge into a Coma-mass cluster by z = 0, to study how galaxy properties may change during cluster assembly. Of the 38 visually classified S0 galaxies, with masses ranging from log (M *)[M ☉] ≈ 10-11, we detect only one in the near-UV (NUV) channel, a strongly star-forming S0 that is the brightest UV source with a measured redshift placing it in SG1120. Stacking the undetected S0 galaxies (which generally lie on or near the optical red sequence of SG1120) still results in no NUV/far-UV (FUV) detection (\u3c2σ). Using our limit in the NUV band, we conclude that for a rapidly truncating star formation rate, star formation ceased at least ~0.1-0.7 Gyr ago, depending on the strength of the starburst prior to truncation. With an exponentially declining star formation history over a range of timescales, we rule out recent star formation over a wide range of ages. We conclude that if S0 formation involves significant star formation, it occurred well before the groups were in this current pre-assembly phase. As such, it seems that S0 formation is even more likely to be predominantly occurring outside of the cluster environment

Why Petty IT Tyrants Are the Real Enemy of Cybersecurity, Productivity, and Innovation

Despite purportedly acting in the best interests of the organization, many Information Technology (IT) managers succumb to desires for control and power that result in behavior that is detrimental to employees and, ultimately, the organization as a whole. Drawing from Ashforth’s seminal work on petty tyranny, we highlight the unique dynamics of IT-related tyranny, characterized by micromanagement and arbitrary control over user activities. Employing models that both illustrate petty tyranny emergence and delineate the lifecycle of IT petty tyranny, this work describes how individual predispositions and organizational factors catalyze and perpetuate tyrannical behaviors. In addition, we examine the harmful effects of IT petty tyranny on employee morale, productivity, and even organizational cybersecurity. We conclude with practical advice on how organizations can recognize and mitigate IT petty tyranny to avoid negative outcomes for employees and the organization