515 research outputs found
ECONOMIC IMPLICATIONS OF ALTERNATIVE COTTON PRODUCTION PRACTICES: TEXAS LOWER RIO GRANDE VALLEY
Crop Production/Industries,
Pilot Weather Advisor System
The Pilot Weather Advisor (PWA) system is an automated satellite radio-broadcasting system that provides nearly real-time weather data to pilots of aircraft in flight anywhere in the continental United States. The system was designed to enhance safety in two distinct ways: First, the automated receipt of information would relieve the pilot of the time-consuming and distracting task of obtaining weather information via voice communication with ground stations. Second, the presentation of the information would be centered around a map format, thereby making the spatial and temporal relationships in the surrounding weather situation much easier to understan
Effect of local environment and stellar mass on galaxy quenching and morphology at
We study galactic star-formation activity as a function of environment and
stellar mass over 0.5<z<2.0 using the FourStar Galaxy Evolution (ZFOURGE)
survey. We estimate the galaxy environment using a Bayesian-motivated measure
of the distance to the third nearest neighbor for galaxies to the stellar mass
completeness of our survey, at z=1.3 (2.0). This
method, when applied to a mock catalog with the photometric-redshift precision
(), recovers galaxies in low- and high-density
environments accurately. We quantify the environmental quenching efficiency,
and show that at z> 0.5 it depends on galaxy stellar mass, demonstrating that
the effects of quenching related to (stellar) mass and environment are not
separable. In high-density environments, the mass and environmental quenching
efficiencies are comparable for massive galaxies (
10.5) at all redshifts. For lower mass galaxies (
10), the environmental quenching efficiency is very low at 1.5, but
increases rapidly with decreasing redshift. Environmental quenching can account
for nearly all quiescent lower mass galaxies ( 9-10),
which appear primarily at 1.0. The morphologies of lower mass
quiescent galaxies are inconsistent with those expected of recently quenched
star-forming galaxies. Some environmental process must transform the
morphologies on similar timescales as the environmental quenching itself. The
evolution of the environmental quenching favors models that combine gas
starvation (as galaxies become satellites) with gas exhaustion through
star-formation and outflows ("overconsumption"), and additional processes such
as galaxy interactions, tidal stripping and disk fading to account for the
morphological differences between the quiescent and star-forming galaxy
populations.Comment: 29 pages, 15 figure, accepted for publication in Ap
Stable Electrical Operation of 6H-SiC JFETs and ICs for Thousands of Hours at 500 C
The fabrication and testing of the first semiconductor transistors and small-scale integrated circuits (ICs) to achieve up to 3000 h of stable electrical operation at 500 C in air ambient is reported. These devices are based on an epitaxial 6H-SiC junction field-effect transistor process that successfully integrated high temperature ohmic contacts, dielectric passivation, and ceramic packaging. Important device and circuit parameters exhibited less than 10% of change over the course of the 500 C operational testing. These results establish a new technology foundation for realizing durable 500 C ICs for combustion-engine sensing and control, deep-well drilling, and other harsh-environment applications
Long-Term Characterization of 6H-SiC Transistor Integrated Circuit Technology Operating at 500 C
NASA has been developing very high temperature semiconductor integrated circuits for use in the hot sections of aircraft engines and for Venus exploration. This paper reports on long-term 500 C electrical operation of prototype 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). As of this writing, some devices have surpassed 4000 hours of continuous 500 C electrical operation in oxidizing air atmosphere with minimal change in relevant electrical parameters
Exploring the divergence between self-assessment and self-monitoring
Many models of professional self-regulation call upon individual practitioners to take responsibility both for identifying the limits of their own skills and for redressing their identified limits through continuing professional development activities. Despite these expectations, a considerable literature in the domain of self-assessment has questioned the ability of the self-regulating professional to enact this process effectively. In response, authors have recently suggested that the construction of self-assessment as represented in the self-regulation literature is, itself, problematic. In this paper we report a pair of studies that examine the relationship between self-assessment (a global judgment of one’s ability in a particular domain) and self-monitoring (a moment-by-moment awareness of the likelihood that one maintains the skill/knowledge to act in a particular situation). These studies reveal that, despite poor correlations between performance and self-assessments (consistent with what is typically seen in the self-assessment literature), participant performance was strongly related to several measures of self-monitoring including: the decision to answer or defer responding to a question, the amount of time required to make that decision to answer or defer, and the confidence expressed in an answer when provided. This apparent divergence between poor overall self-assessment and effective self-monitoring is considered in terms of how the findings might inform our understanding of the cognitive mechanisms yielding both self-monitoring judgments and self-assessments and how that understanding might be used to better direct education and learning efforts
A justification of whistleblowing
Penultimate version accepted for publicationWhistleblowing is the act of disclosing information from a public or private organization in order to reveal cases of corruption that are of immediate or potential danger to the public. Blowing the whistle involves personal risk, especially when legal protection is absent, and charges of betrayal, which often come in the form of legal prosecution under treason laws. In this article we argue that whistleblowing is justified when disclosures are made with the proper intent and fulfill specific communicative constraints in addressing issues of public interest. Three communicative constraints of informativeness, truthfulness and evidence are discussed in this regard. We develop a ‘harm test’ to assess the intent for disclosures, concluding that it is not sufficient for justification. Along with the proper intent, a successful act of whistleblowing should provide information that serves the public interest. Taking cognizance of the varied conceptions of public interest, we present an account of public interest that fits the framework of whistleblowing disclosures. In particular, we argue that whistleblowing is justified inter alia when the information it conveys is of a presumptive interest for a public insofar as it reveals an instance of injustice or violation of a civil or political right done against and unbeknown to some members of a polity.Project: ‘Change of Direction. Fostering Whistleblowing in the Fight against Corruption’ co-funded by the Internal Security Fund of the European Union (Grant Agreement Number: HOME/2014/ISFP/AG/EFCE/7233); SFRH/BPD/108669/2015info:eu-repo/semantics/publishedVersio
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Calculations of double cylinder implosions at OMEGA
Foam-filled double cylinder targets have been imploded by the OMEGA laser at the University of Rochester. A marker layer of heavier material is placed between the foam and the outside ablator. The marker layer is hydrodynamically unstable when a strong shock passes through both these interfaces and the marker layer material mixes into the foam and the ablator. These experiments thus measure mix in the compressible, convergent, miscible, strong-shock regime. With double cylinder targets, the initial shock converges on the central cylinder and then rebounds and expands. The shock is predicted to create even more mixing of the marker layer as it traverses the previously mixed region. The strength of the reflected shock can be varied by changing the materials in the inner cylinder. Calculations of these implosions using the AMR code, RAGE, are presented for the several target designs. The 2-d calculations give the hydrodynamic evolution of the implosion, shock timings, and the growth of the mix width. The calculations include the effects of surface roughness in the marker layer. Simulated radiographs of the cylindrical implosions are also shown
Lead exposure in adult males in urban Transvaal Province, South Africa during the apartheid era
Human exposure to lead is a substantial public health hazard worldwide and is particularly problematic in the Republic of South Africa given the country’s late cessation of leaded petrol. Lead exposure is associated with a number of serious health issues and diseases including developmental and cognitive deficiency, hypertension and heart disease. Understanding the distribution of lifetime lead burden within a given population is critical for reducing exposure rates. Femoral bone from 101 deceased adult males living in urban Transvaal Province (now Gauteng Province), South Africa between 1960 and 1998 were analyzed for lead concentration by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Of the 72 black and 29 white individuals sampled, chronic lead exposure was apparent in nearly all individuals. White males showed significantly higher median bone lead concentration (ME = 10.04 µg·g−1), than black males (ME = 3.80 µg·g−1) despite higher socioeconomic status. Bone lead concentration covaries significantly, though weakly, with individual age. There was no significant temporal trend in bone lead concentration. These results indicate that long-term low to moderate lead exposure is the historical norm among South African males. Unexpectedly, this research indicates that white males in the sample population were more highly exposed to lead
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