1,631 research outputs found
Economics of Marital Instability
This paper focuses on the causes of divorce. Section I developsa theoretical analysis of marital dissolution incorporating uncertaintyabout the outcomes of marital decisions into a framework of utilitymaximization and the marriage market. Section II explores the implica-tions of the theoretical analysis with cross-sectional data,primarilythe 1967 Survey of Economic Opportunity and the Terman sample. Therelevance of both the theoretical and empirical analyses in explainingthe recent acceleration in the U.S. divorce rate is discussed.
Spectroscopic Properties of the z=4.5 Lyman-alpha Emitters
We present Keck/LRIS optical spectra of 17 Lya-emitting galaxies and one
Lyman break galaxy at z=4.5 discovered in the Large Area Lyman Alpha (LALA)
survey. The survey has identified a sample of ~350 candidate Lya-emitting
galaxies at z=4.5 in a search volume of 1.5 x 10^6 comoving Mpc^3. We targeted
25 candidates for spectroscopy; hence, the 18 confirmations presented herein
suggest a selection reliability of 72%. The large equivalent widths (median
W(rest)~80 A) but narrow physical widths (v < 500 km/s) of the Lya emission
lines, along with the lack of accompanying high-ionization state emission
lines, suggest that these galaxies are young systems powered by star formation
rather than by AGN activity. Theoretical models of galaxy formation in the
primordial Universe suggest that a small fraction of Lya-emitting galaxies at
z=4.5 may still be nascent, metal-free objects. Indeed, we find with 90%
confidence that 3 to 5 of the confirmed sources show W(rest) > 240 A, exceeding
the maximum Lya equivalent width predicted for normal stellar populations.
Nonetheless, we find no evidence for HeII 1640 emission in either individual or
composite spectra, indicating that though these galaxies are young, they are
not truly primitive, Population III objects.Comment: 12 pages, Accepted to Ap
Spectroscopic Confirmation of Three Redshift 5.7 Lyman-alpha Emitters from the Large Area Lyman Alpha Survey
Narrow-band searches for Lyman alpha emission are an efficient way of
identifying star-forming galaxies at high redshifts. We present Keck telescope
spectra confirming redshifts z = 5.7 for three objects discovered in the Large
Area Lyman Alpha (LALA) survey at Kitt Peak National Observatory.
All three spectra show strong, narrow emission lines with the asymmetric
profile that is characteristically produced in high redshift Lyman alpha
emitters by preferential HI absorption in the blue wing of the line. These
objects are undetected in deep Bw, V, R, and 6600A narrow-band images from the
NOAO Deep Wide-Field Survey and from LALA, as expected from Lyman break and
Lyman alpha forest absorption at redshift z = 5.7. All three objects show large
equivalent widths (>= 150A in the rest-frame), suggesting at least one of the
following: a top-heavy initial mass function, very low stellar metallicity, or
the presence of an active nucleus. We consider the case for an active nucleus
to be weak in all three objects due to the limited width of the Lyman alpha
emission line (< 500 km/s) and the absence of any other indicator of quasar
activity.
The three confirmed high redshift objects were among four spectroscopically
observed targets drawn from the sample of 18 candidates presented by Rhoads and
Malhotra (2001). Thus, these spectra support the Lyman alpha emitter population
statistics from our earlier photometric study, which imply little evolution in
number density from z=5.7 to z=4.5 and provide strong evidence that the
reionization redshift is greater than 5.7.Comment: Submitted to AJ, June 2002. 15 pages, AASTe
An audit of antimicrobial prescribing by dental practitioners in the north east of England and Cumbria
Background
Inappropriate prescribing of antimicrobials is a significant threat to global public health. In England, approximately 5% of all antimicrobial items are prescribed by dentists, despite the limited indications for their use in the treatment of oral infections in published clinical guidelines. The objective of this study was to survey antimicrobial prescribing by dental practitioners in North East England and Cumbria, identify educational and training needs and develop a self-assessment tool that can be used for Continued Professional Development by individual practitioners.
Methods
During October 2016, 275 dental practitioners used a standardised form to record anonymous information about patients who had been prescribed antimicrobials. Clinical information and prescribing details were compared against clinical guidelines published by the Faculty of General Dental Practitioners UK.
Results
Dental practitioners provided data on 1893 antimicrobial prescriptions. There was documented evidence of systemic spread, such as pyrexia in 18% of patients. Dentists recorded patients’ pain (91.1% of patients), local lymph gland involvement (41.5%) gross diffuse swelling (55.5%) dysphagia (7.2%) and trismus (13.6%). Reasons for prescribing antimicrobials included patient expectations (25.8%), patient preference (24.8%), time pressures (10.9%), and patients uncooperative with other treatments (10.4%). The most commonly prescribed antimicrobials were amoxicillin, accounting for 61.2% of prescriptions, followed by metronidazole (29.9%). Most prescriptions for amoxicillin were for either 5 days (66.8%) or 7 days (29.6%) and most prescriptions for metronidazole were for a 5-day course (65.2%) or 7-day (18.6%) course.
Conclusion
In most cases, when an antimicrobial was prescribed, practitioners used the correct choice of agents and usually prescribed these at the correct dose. However, some evidence of suboptimal prescribing practices when compared to the Faculty of General Dental Practitioner guidelines were identified. The audit has identified training needs across the region and aided the development of Continued Professional Development sessions. Further work to identify barriers and facilitators for improving antimicrobial prescribing and determining appropriate methods to improve clinical practice are required
Extension of an automatic building extraction technique to airborne laser scanner data containing damaged buildings
Airborne laser scanning systems generate 3-dimensional point clouds of high density and irregular spacing. These data consist of multiple returns coming from terrain, buildings, and vegetation. The major difficulty is the extraction of object categories, usually buildings. In the field of disaster management, the detection of building damages plays an important role. Therefore, the question arises, if damaged buildings can also be detected by a method developed for the automatic extraction of buildings. Another purpose of this study is to extend and test an automatic building detection method developed initially for first echo laser scanner data on data captured in first and last echo. In order to answer these two questions, two institutes share their data and knowledge: the Institute of Photogrammetry and Remote Sensing (IPF, Universität Karlsruhe (TH), Germany) and the MAP-PAGE team (INSA de Strasbourg, France). The used 3D LIDAR data was captured over an area containing undamaged and damaged buildings. The results achieved for every single processing step by applying the original and the extended algorithm to the data are presented, analysed and compared. It is pointed out which buildings can be extracted by which algorithm and why some buildings remain undetecte
Extension of an automatic building extraction technique to airborne laser scanner data containing damaged buildings
NONLINEAR MODELS FOR MULTI-FACTOR PLANT NUTRITION EXPERIMENTS
Plant scientists are interested in measuring plant response to quantitative treatment factors, e.g. amount of nutrient applied. Response surface methods are often used for experiments with multiple quantitative factors. However, in many plant nutrition studies, second-order response surface models result in unacceptable lack of fit. This paper explores multi-factor nonlinear models as an alternative. We have developed multi-factor extensions of Mitscherlich and Gompertz models, and fit them to data from experiments conducted at the University of Nebraska-Lincoln Horticulture department. These data are typical of experiments for which conventional response surface models perform poorly. We propose design selection strategies to facilitate economical multi-factor experiments when second-order response surface models are unlikely to fit
Prevalence of Noncardiac Findings in Patients Undergoing Cardiac Magnetic Resonance Imaging
Purpose. We sought to determine the prevalence of clinically significant non-cardiac abnormalities found in pediatric and adult patients undergoing cardiac magnetic resonance imaging (CMRI), and understand the impact of age on it's occurrence. Methods. We retrospectively reviewed all patients undergoing CMRI between May 2004 and July 2007. Findings were considered significant if they required radiographic or clinical follow-up. Results. A total of 408 patients underwent CMRI during the study period. Twenty two (16%) pediatric patients (age < 19 years, n = 135) were found to have a total of 22 non- cardiac abnormalities, 3 of which were clinically significant. Sixty four (23%) adult patients (age > 19 years, n = 273) were found to have a total of 77 non-cardiac abnormalities, 33 of which were clinically significant. The prevalence of clinically significant non-cardiac abnormalities was 2% in the pediatric cohort and 11% in the adult cohort (P = 0.05). Within the adult population, the prevalence of significant non-cardiac abnormalities increased with advancing age (P = 0.05). Conclusions. In a population of unselected patients undergoing CMRI, unanticipated noncardiac abnormalities were frequently seen. A small number of these were significant, with the prevalence increasing with age
Analisis Laporan Keuangan Sebagai Alat Dalam Memprediksi Kecenderungan Terjadinya Kebangkrutan Pada Bank Umum Syariah; Bni Syariah, Bri Syariah, Mandiri Syariah, Mega Syariah, Bukopin Syariah (Suatu Studi Penggunaan Model Altman\u27s Z-score)
Kebangkrutan Perusahaan merupakan salah satu fenomena yang sering terjadidalam dunia USAha, baik itu dipengaruhi oleh pihak internal maupun eksternal Perusahaan. Untuk mengantisipasi terjadinya kebangkrutan, maka pihak Perusahaan seharusnya ada persiapan dini untuk mencegah agar tidak terjadi hal yang tidak diinginkan. Perusahaan dapat menilai kondisi Perusahaannya yang sedang berjalan, agar dapat mengetahui tindakan apa yang tepat untuk memperbaiki kekurangan dan mempertahankan Perusahaannya agar Perusahaan dapat bertahan dan bersaing, salah satu Perusahaan yang ada di Indonesia adalah Bank Umum Syariah. Tujuan dari penelitian ini adalah untuk memprediksi kecenderungan terjadinya kebangkrutan pada Bank Umum Syariah menggunakan modelAltman. Data yang digunakan dalam penelitian ini adalah data sekunder berupa laporan keuangan tahunan yang telah dipublikasikan oleh perbankan syariah periode 2010 sampai 2014. Bank Umum Syariah tersebut terdiri dari PT.BNI Syariah, PT.BRI Syariah, PT.Bank Mandiri Syariah, PT. Bank Mega Syariah dan PT.Bank Syariah Bukopin. Data diolah dengan menggunakan model Altman. Hasil dari penelitian ini menunjukkan bahwa model Altman dapat digunakan sebagai alat dalam memprediksi kecenderungan kebangkrutan Bank Umum Syariah. Dengan menggunakan model Altman, kita dapat mengetahui apakah Bank Umum Syariah berada dalam kategori bangkrut, grey area, dan tidak bangkrut. Apabila Bank Umum Syariah berada dalam kategori bangkrut, manajemen Perusahaan berhak untuk memutuskan apakah akan tetap mempertahankan Bank Syariahnya atau tidak. Bila tetap mempertahankan Bank Syariahnya, manajemen Bank Syariah diharapkan dapat mengambil tindakan yang cepat dan tepat untuk memperbaiki Bank Syariahnya tersebut, agar Bank Syariahnya tetap dapat berjalan dengan baik
Electrochemically mediated separation for carbon capture
Carbon capture technology has been proposed as an effective approach for the mitigation of anthropogenic CO[subscript 2] emissions. Thermal-swing separation technologies based on wet chemical scrubbing show potential for facilitating CO[subscript 2] capture at industrial-scale carbon emitters; however, the total operational and capital costs resulting from the high energy consumption are prohibitive for their implementation. Electrochemically mediated processes are proposed to be the next generation of CO[subscript 2] separation technology that can enable carbon capture to be a more viable option for carbon mitigation in the near future. This technology utilizes electrochemically active sorbents that undergo significant changes in their molecular affinity for CO[subscript 2] molecules as they progress through an electrochemical cycle. This nearly isothermal separation process consumes electrical energy to facilitate effective CO[subscript 2] capture and regeneration processes under more benign conditions of sorption and desorption than in traditional continuous wet-scrubber operations. This electrically driven separation process has the potential to significantly reduce the difficulty of retrofitting CO[subscript 2] capture units to existing fossil fuel-fired power generators. The ease of installing an electrically driven separation system would also allow its application to other industrial carbon emitters. The design of such a system, however, requires careful consideration since it involves both heterogeneous electrochemical activation/deactivation of sorbents and homogeneous complexation of the activated sorbents with CO[subscript 2] molecules. Optimization of the energy efficiency requires minimizing the irreversibility associated with these processes. In this study, we use a general exergy analysis to evaluate the minimum thermodynamic work based on the system design and the electrochemical parameters of quinodal redox-active molecules. Using this thermodynamic framework, our results suggest that the proposed technology could capture CO[subscript 2] from a dilute post-combustion flue gas and regenerate CO[subscript 2] at 1 bar with high efficiency, if a two-stage design is effectively implemented.Siemens Corporation (Massachusetts Institute of Technology. Center of Knowledge Interchange Project Fund
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