1,723 research outputs found
Water-management models in Florida from ERTS-1 data
The author has identified the following significant results. The usefullness of ERTS 1 to improving the overall effectiveness of collecting and disseminating data was evaluated. ERTS MSS imagery and in situ monitoring by DCS were used to evaluate their separate and combined capabilities. Twenty data collection platforms were established in southern Florida. Water level and rainfall measurements were collected and disseminated to users in less than 2 hours, a significant improvement over conventional techniques requiring 2 months. ERTS imagery was found to significantly enhance the utility of ground measurements. Water stage was correlated with water surface areas from imagery in order to obtain water stage-volume relations. Imagery provided an economical basis for extrapolating water parameters from the point samples to unsampled data and provided a synoptic view of water mass boundaries that no amount of ground sampling or monitoring could provide
Advantages of ERTS data collection system in south Florida
There are no author-identified significant results in this report
Acquisition and processing problem of ERTS data in south Florida
There are no author-identified significant results in this report
Surface water modeling Everglades Water Basin, Florida
There are no author-identified significant results in this report
Polarized mm And sub-mm Emission From Sgr A* At The Galactic Center
The recent detection of significant linear polarization at mm and sub-mm
wavelengths in the spectrum of Sgr A* (if confirmed) will be a useful probe of
the conditions within several Schwarzschild radii () of the event horizon
at the Galactic Center. Hydrodynamic simulations of gas flowing in the vicinity
of this object suggest that the infalling gas circularizes when it approaches
within of the black hole. We suggest that the sub-mm ``excess'' of
emission seen in the spectrum of Sgr A* may be associated with radiation
produced within the inner Keplerian region and that the observed polarization
characteristics provide direct evidence for this phenomenon. The overall
spectrum from this region, including the high-energy component due to
bremsstrahlung and inverse Compton scattering processes, is at or below the
recent {\it Chandra} measurement, and may account for the X-ray source if it
turns out to be the actual counterpart to Sgr A*.Comment: 12 pages, 2 figures. published in APJ Letter
Crime and Psychiatric Disorders Among Youth in the US population: An Analysis of the National Comorbidity Survey-Adolescent Supplement
Objective Current knowledge regarding psychiatric disorders and crime in youth is limited to juvenile justice and community samples. This study examined relationships between psychiatric disorders and self-reported crime involvement in a sample of youth representative of the US population. Method The National Comorbidity Survey–Adolescent Supplement (N = 10,123; ages 13–17 years; 2001–2004) was used to examine the relationship between lifetime DSM-IV–based diagnoses, reported crime (property, violent, other), and arrest history. Logistic regression compared the odds of reported crime involvement with specific psychiatric disorders to those without any diagnoses, and examined the odds of crime by psychiatric comorbidity. Results Prevalence of crime was 18.4%. Youth with lifetime psychiatric disorders, compared to no disorders, had significantly greater odds of crime, including violent crime. For violent crime resulting in arrest, conduct disorder (CD) (odds ratio OR = 57.5; 95% CI = 30.4, 108.8), alcohol use disorders (OR = 19.5; 95% CI = 8.8, 43.2), and drug use disorders (OR = 16.1; 95% CI = 9.3, 27.7) had the greatest odds with similar findings for violent crime with no arrest. Psychiatric comorbidity increased the odds of crime. Youth with 3 or more diagnoses (16.0% of population) accounted for 54.1% of those reporting arrest for violent crime. Youth with at least 1 diagnosis committed 85.8% of crime, which was reduced to 67.9% by removing individuals with CD. Importantly, 88.2% of youth with mental illness reported never having committed any crime. Conclusion Our findings highlight the importance of improving access to mental health services for youthful offenders in community settings, given the substantial associations found between mental illness and crime in this nationally representative epidemiological sample
Determination of the characteristic directions of lossless linear optical elements
We show that the problem of finding the primary and secondary characteristic
directions of a linear lossless optical element can be reformulated in terms of
an eigenvalue problem related to the unimodular factor of the transfer matrix
of the optical device. This formulation makes any actual computation of the
characteristic directions amenable to pre-implemented numerical routines,
thereby facilitating the decomposition of the transfer matrix into equivalent
linear retarders and rotators according to the related Poincare equivalence
theorem. The method is expected to be useful whenever the inverse problem of
reconstruction of the internal state of a transparent medium from optical data
obtained by tomographical methods is an issue.Comment: Replaced with extended version as published in JM
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