660 research outputs found
Application of diffusion bonding to electronic interconnection of flatpack leads
Diffusion-bonded joints between gold-plated Kovar leads and indium-plated copper circuit pads offer some advantages for electronic circuit packaging. Test results show that consistent high strength bonds stronger than the copper circuit foil are achieved by parallel-gap bonding at relatively low power settings. The bonds are basically formed by the alloying of the gold, indium and copper at the bond interface. Other low melting metals such as tin can also be used; however, tin does not offer the ease of bonding that results in consistent separation of the copper foil during pull testing. The investigation was conducted in three parts consisting of: (1) an evaluation of the physical strength of resulting bonds at ambient and elevated temperature, (2) a metallurgical analysis of bonds using scanning electron microscopy and nondispersive X-ray analysis, and (3) evaluation and development of various schemes for multiple lead flatpack bonding
PROFIT PATTERNS IN THE U.S. AND THE WEST, 1992 AND 1997: WHAT COUNTY-LEVEL DATA REVEAL
We examine whether there are spatial relationships in U.S. production agriculture's profitability across regions and over time. We test the traditional view that factor markets (approximately) adjust to equalize agriculture's net returns over space and time using county-level data from the UDSA's Census of Agriculture, 1992 and 1997. We estimate Gini coefficients and calculate the Theil Entropy Measure (TMI) to examine changes in the concentration of returns over space and time, and to decompose the variation in inequality in returns due to between-region variation in returns. Although factor markets (approximately) adjust to equalize net returns over space and time, there is still considerable variability in returns within regions and within states. Use of county-level (Census of Agriculture) and farm-level data (ARMS Survey) to help highlight these differences. In general, farm-level Gini coefficients have remained fairly constant but show a mild increase in concentration since the 1996 FAIR Act. The TMI analysis reveals that in 1997 about 54 percent of the variation in total returns (net cash returns) was due to within-region variation, and about 46 percent was due to (average) between-region variation (compared to 53 and 47 percent in 1992). Total U.S. inequity of net cash returns increased from 0.14 in 1992 to 0.21 in 1997.Gini coefficient, Theil Entropy Measure, net cash returns, net cash and net farm income, farm structure, Agricultural Finance, Community/Rural/Urban Development, Q, Q140,
Recent Changes in Farm Structure: A Canada-U.S. Comparison
Following a series of bilateral and multilateral agreements, the past two decades have seen increased trade and investment liberalization between Canada and the United States in the agri-food sector. Changes in trade policy are one of several paths by which farm structure can change. This increased liberalization, together with the largest drop in Canadian farm numbers recorded by the Census of Agriculture in thirty years, has provided the impetus to review some aspects of farm structure. In particular, this article presents the latest Canadian and U.S. data on the number of farms by sales class, the concentration of sales and other production-related variables, and the distribution of income and receipts. We explore whether significant changes in the latter two elements of farm structure have occurred during this period of trade and investment liberalization.Crop Production/Industries, Farm Management, International Relations/Trade,
Fingerprints of the Magnetic Polaron in Nonequilibrium Electron Transport through a Quantum Wire Coupled to a Ferromagnetic Spin Chain
We study nonequilibrium quantum transport through a mesoscopic wire coupled
via local exchange to a ferromagnetic spin chain. Using the Keldysh formalism
in the self-consistent Born approximation, we identify fingerprints of the
magnetic polaron state formed by hybridization of electronic and magnon states.
Because of its low decoherence rate, we find coherent transport signals. Both
elastic and inelastic peaks of the differential conductance are discussed as a
function of external magnetic fields, the polarization of the leads and the
electronic level spacing of the wire.Comment: 5 pages, 4 figure
Atmospheric transmission computer program CP
A computer program is described which allows for calculation of the effects of carbon dioxide, water vapor, methane, ozone, carbon monoxide, and nitrous oxide on earth resources remote sensing techniques. A flow chart of the program and operating instructions are provided. Comparisons are made between the atmospheric transmission obtained from laboratory and spacecraft spectrometer data and that obtained from a computer prediction using a model atmosphere and radiosonde data. Limitations of the model atmosphere are discussed. The computer program listings, input card formats, and sample runs for both radiosonde data and laboratory data are included
Bayesian Network Structure Learning with Permutation Tests
In literature there are several studies on the performance of Bayesian
network structure learning algorithms. The focus of these studies is almost
always the heuristics the learning algorithms are based on, i.e. the
maximisation algorithms (in score-based algorithms) or the techniques for
learning the dependencies of each variable (in constraint-based algorithms). In
this paper we investigate how the use of permutation tests instead of
parametric ones affects the performance of Bayesian network structure learning
from discrete data. Shrinkage tests are also covered to provide a broad
overview of the techniques developed in current literature.Comment: 13 pages, 4 figures. Presented at the Conference 'Statistics for
Complex Problems', Padova, June 15, 201
Patterns of comorbidity and psychopharmacology in adults with intellectual disability and attention deficit hyperactivity disorder: an UK national cross-sectional audit.
Background: Attention-deficit hyperactivity disorder (ADHD) is higher in people with intellectual disability (ID) compared to the general population. Available limited evidence suggests this population has increased psychological problems, diagnostic overshadowing and psychotropic prescribing. This audit Identifies and analyzes real-world characteristics, diagnostic practices, treatment, and management of ADHD in adults with ID.Research Design and Methods: Pooled retrospective case note data for people with ID and ADHD, collected from 30 organizations across the UK, were analyzed. Patients were classified into mild and moderate-profound ID groups. Associated mental health and neurodevelopmental co-morbidity, Demographics, concomitant psychotropics, and mental and behavioral concerns were collected. Group differences were reported using logistic regression models.Results: Of 445 participants, 73% had co-occurring autism spectrum disorder (ASD) and 65% were prescribed ADHD medications. Those on ADHD medication were less likely to be prescribed antipsychotics (p < 0.001) and antidepressants (p < 0.001). Multiple significant differences were found in ADHD medication response between ID groups and those with/without co-morbid ASD but not associated with challenging behavior reduction.Conclusions: High levels of neurodevelopmental and psychiatric comorbidity were found. ID severity and the presence of ASD appear to influence the use of certain psychotropic medications. Appropriate use of ADHD medication appears to reduce psychotropic polypharmacy
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