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Past Work (past + work)
Selected AbstractsII. Review of Past WorkMONOGRAPHS OF THE SOCIETY FOR RESEARCH IN CHILD DEVELOPMENT, Issue 2 2002Lynn S. Liben First page of article [source] Globalization and Restructuring during Downturns: A Case Study of CaliforniaGROWTH AND CHANGE, Issue 2 2001Ashok Deo Bardhan Restructuring through foreign outsourcing, whereby greater imports of manufactured inputs substitute for blue-collar labor, is shown to intensify when industries experience declines in sales. The magnitude of this effect was four to seven times greater in California industries experiencing a 20 percent sales decline from 1987-1992, relative to those industries whose sales dropped by 5 percent. Foreign outsourcing explains a quarter to two-fifths of the rise in payroll inequality between blue and white collar workers in California and perhaps five to ten percent of the rise in the remainder of the U.S. Past work linked growing inequality with foreign outsourcing and restructuring with economic downturns. Here, foreign outsourcing is used as an example of a particular efficiency augmenting measure, which occurs predominantly, though not exclusively, in troubled industries. [source] Correlated, relativistic, and basis set limit molecular polarizability calculations to evaluate an augmented effective core potential basis setINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2006Nicholas P. Labello Abstract Initial investigations have demonstrated that an augmented ECP basis set can be used to calculate valence electronic properties with deviations of less than 1% from all-electron basis sets. Past work has largely focused on molecules with relatively light atoms (Z<18) examined with time-dependent Hartree,Fock (TDHF) theory. In this work, the dipole moment and polarizability of a number of well-studied molecules are examined with HF, MP2, CCSD, and CCSD(T) correlated wave functions. Additionally, systems not as thoroughly studied due to the difficulty of all-electron calculations when Z=50,85 are included. The SBK ECP basis set, augmented with optimized valence functions, performs well across a broad range of methods, less than 3% different from all electron relativistic and correlated wave functions. Orders of magnitude time savings (101,104) are exchanged for a minimal difference from all-electron basis sets. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] Modeling of partial oxidation in gas,solids downer reactorsAICHE JOURNAL, Issue 8 2010S. Vaishali Abstract Selective partial oxidations represent an important class of reactions in the process industry. Of particular interest is the partial oxidation of n-butane to maleic anhydride (MAN), which is arguably the largest commercialized alkane partial oxidation process. Partial oxidation of n-butane, which uses vanadium phosphorous oxide (VPO) as a heterogeneous catalyst, is believed to operate through a unique mechanism in which lattice oxygen oxidizes n-butane selectively to MAN. Past work has shown that performing partial oxidation reactions in gas,solids riser configuration is realizable and commercially viable, which has lead to commercialization of this technology in the last decade. Though the riser configuration allows optimal and independent control of the oxidation and reduction steps, the riser unit suffers from solid backmixing at walls, which in turn result into lower conversion, nonoptimal selectivity and diminished overall yield of desired product. In recent years, there has been growing interest in downers involving cocurrent downflow of both solids and gas phases, hence offering relatively uniform flow characteristics. In this contribution, we explore through modeling the implications of effecting partial oxidation reactions in a downer (gas,solids cocurrent downflow) compared to that in a conventional riser reactor (gas,solids cocurrent up flow) operated under equivalent operating conditions. Further, we explore the operational space of downers for these reactions, suggesting ways for improving the productivity of downer for partial oxidation applications. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] RSA fluctuation in major depressive disorderPSYCHOPHYSIOLOGY, Issue 3 2007Jonathan Rottenberg Abstract Cardiac vagal control, as measured by indices of respiratory sinus arrhythmia (RSA), has been investigated as a marker of impaired self-regulation in mental disorders, including depression. Past work in depressed samples has focused on deficits in resting RSA levels, with mixed results. This study tested the hypothesis that depression involves abnormal RSA fluctuation. RSA was measured in depressed and healthy control participants during rest and during two reactivity tasks, each followed by a recovery period. Relative to controls, depressed persons exhibited lower resting RSA levels as well as less RSA fluctuation, primarily evidenced by a lack of task-related vagal suppression. Group differences in RSA fluctuation were not accounted for by differences in physical health or respiration, whereas group differences in resting RSA level did not survive covariate analyses. Depression may involve multiple deficits in cardiac vagal control. [source] COMMENTARY: Silver Bullet Junkies and the Codifiers That Love Them: Behavioral Roots Behind a Legacy of Bad Modeling and UseDECISION SCIENCES, Issue 2 2008Elliot Bendoly ABSTRACT As research continues to evolve, it is important to look back with a critical eye on its impact on practice and what is guiding its trajectory into the future. In this work we discuss some of the key behavioral drivers that taken as a whole have made for a less than ideal relationship between research, model development, and use/reliance in practice. From a general public-good perspective, there is an obvious need for academics to take on a greater role of responsibility when it comes to both research and curriculum in an effort to avoid some of the failings that our past work has inevitably encouraged to date. [source] Medical comorbidity in late-life depressionINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 10 2004Warren D. Taylor Abstract Objectives Medical comorbidity is common in elderly patients with depression, however the difference between depressed and non-depressed elderly populations is not well established. Additionally, differences between subgroups of depressed populations, including those with MRI-defined vascular depression and those with late-onset compared with early-onset depression are not well described. Methods We compared self-report of medical disorders between 370 depressed elders and 157 non-depressed control subjects. Subjects were additionally dichotomized based on presence or absence of subcortical MRI lesions and age of onset. Medical comorbidity was assessed by self report only, and depressed subjects were additionally assessed by the clinician-rated Cumulative Illness Rating Scale. Results When compared with the non-depressed group, depressed subjects were significantly more likely to report the presence of hypertension, heart disease, gastrointestinal ulcers, and ,hardening of the arteries'. Analyses of subjects with subcortical disease demonstrated they were significantly older, more likely to have depression, and more likely to report the presence of hypertension. Finally, the depressed cohort with late-onset depression (occurring after age 50 years) had more male subjects, exhibited greater CIRS scores, and greater prevalence of hypertension, but these did not reach a level of statistical significance after applying a Bonferroni correction. Conclusions Vascular comorbidities are common in depressed elders. The differences in the report of hypertension supports past work investigating a vascular contribution to late-life depression. Given the association between depression and poor medical outcomes of cardiac disease, this population deserves clinical scrutiny and further research. Copyright © 2004 John Wiley & Sons, Ltd. [source] Families With Children and Adolescents: A Review, Critique, and Future AgendaJOURNAL OF MARRIAGE AND FAMILY, Issue 3 2010Robert Crosnoe This decade's literature on families with children and adolescents can be broadly organized around the implications for youth of family statuses (e.g., family structure) and family processes (e.g., parenting). These overlapping bodies of research built on past work by emphasizing the dynamic nature of family life and the intersection of families with other ecological settings, exploring race/ethnic diversity, identifying mechanisms connecting family and child/adolescent factors, and taking steps to address the threats to causal inference that have long been a problem for family studies. Continuing these trends in the future will be valuable, as will increasing the number of international comparisons, exploring "new" kinds of family diversity, and capturing the convergence of multiple statuses and processes over time. [source] Strain-engineered novel III,N electronic devices with high quality dielectric/semiconductor interfacesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003M. Asif Khan Abstract Since the early demonstration of 2D-electron gas [M. A. Khan et al., Appl. Phys. Lett. 60, 3027 (1992)] and a heterojunction field effect transistor (HFET) [M. Asif Khan et al., Appl. Phys. Lett. 63, 1214 (1993)] in III,N materials, rapid progress has been made to improve the DC and RF performance of GaN,AlGaN based HFETs. Stable and impressive microwave powers as high as 4,8 W/mm have been reported for device operation frequencies from 10 to 35 GHz. The key reason for these high performance numbers is an extremely large sheet carrier densities (>1 × 1013 cm,2) that can be induced at the interfaces in III,N hetereojunction [A. Bykhovsk et al., J. Appl. Phys. 74, 6734 (1993); M. Asif Khan et al., Appl. Phys. Lett. 75, 2806 (1999)]. These are instrumental in screening the channel dislocations thereby retaining large room temperature carrier mobilities (>1500 cm2/Vs) and sheet resistance as low as 300 ,/sq. These numbers and the high breakdown voltages of the large bandgap III,N material system thus enable rf-power approximately 5,10 times of that possible with GaAs and other competitor's technologies. We have recently introduced a unique pulsed atomic layer epitaxy approach to deposit AlN buffer layers and AlN/AlGaN superlattices [J. Zhang et al., Appl. Phys. Lett. 79, 925 (2001); J. P. Zhang et al., Appl. Phys. Lett. 80, 3542 (2002)] to manage strain and decrease the dislocation densities in high Al-content III,N layers. This has enabled us to significantly improve GaN/AlGaN hetereojunctions and the device isolation. The resulting low defect layers are not only key to improving the electronic but also deep ultraviolet light-emitting diode devices. For deep UV LED's they enabled us to obtain peak optical powers as high as 10 mW and 3 mW for wavelengths as short as 320 nm and 278 nm. Building on our past work [M. Asif Khan et al., Appl. Phys. Lett. 77, 1339 (2000); X. Hu et al., Appl. Phys. Lett. 79, 2832 (2001)] we have now deposited high quality SiO2/Si3N4 films over AlGaN with low interface state densities. They have then been used to demonstrate III,N insulating gate transistors (MOSHFET (SiO2) and MISHFET (Si3N4) with gate leakage currents 4,6 order less than those for conventional GaN,AlGaN HFETs. The introduction of the thin insulator layers (less then 100 Å) under the gate increases the threshold voltage by 2,3 V. In addition, it reduces the peak transconductance gm. However the unity cut-off frequency, the gain and the rf-powers remain unaffected as the gm/Cgs (gate-source capacitance) ratio remains unchanged. In addition to managing the defects and gate leakage currents we have also employed InGaN channel double heterojunction structures (AlInGaN,InGaN,GaN) to confine the carriers thereby reducing the spillover into trappings states. These InGaN based MOS-DHFETs exhibited no current-collapse, extremely low gate leakage currents (<10,10 A/mm) and 10,26 GHz rf-powers in excess of 6 W/mm. We have also demonstrated the scalability and stable operation of our new and innovative InGaN based insulating gate heterojunction field effect transistor approach. In this paper we will review the III,N heterojunction field-effect transistors progress and pioneering innovations including the excellent work from several research groups around the world. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Reconsideration of the physical and empirical origins of Z,R relations in radar meteorologyTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 572 2001A. R. Jameson Abstract The rainfall rate, R, and the radar reflectivity factor, Z, are represented by a sum over a finite number of raindrops. It is shown here and in past work that these variables should be linearly related. Yet observations show that correlations between R and Z are often more appropriately described by nonlinear power laws. In the absence of measurement effects, why should this be so? In order to justify this observation, there have been many attempts to create physical ,explanations' for power laws. However, the present work argues that, because correlations do not prove causation (an accepted fact in the statistical sciences), such explanations are suspect, particularly since the parametric fits are not unique and because they exhibit fundamental physical inconsistencies. So why, then, do so many correlations fit power laws when physical arguments show that Z and R should be related linearly? It is shown in the present work that physically based, linear, relations between Z and R apply in statistically homogeneous rain. (Note that statistical homogeneity does not mean that the rain is spatially uniform.) In contrast, nonlinear power laws are empirical fits to correlated, but statistically inhomogeneous data. This conclusion is proven theoretically after developing a ,generalized' Z,R relation based upon physical consideration of R and Z as random variables. This relation explicitly incorporates details of the drop microphysics as well as the variability in measurements of Z and R. In statistically homogeneous rain, this generalized expression shows that the coefficient relating Z and R is a constant resulting in a linear Z,R relation. In statistically inhomogeneous rain, however, the coefficient varies in an unknown fashion so that one must resort to statistical fits, often power laws, in order to relate the two quantities empirically over widely varying conditions. This conclusion is independently verified using Monte Carlo simulations of rain from earlier work and is also corroborated using disdrometer observations. Thus, the justification for nonlinear power-law Z,R relations is not physical, but rather statistical, in that they provide convenient parametric fits for estimating mean R from measured mean Z in statistically inhomogeneous rain. Finally, examples based upon disdrometer data suggest that such generalized relations between two variables defined by such sums are potentially useful over a wide range of remote-sensing problems and over a wide range of scales. The examples also offer hope that data collected over disparate sampling-volumes and sampling-frequencies can still be combined to yield meaningful estimates. Although additional testing is required, this allows us to write programs which combine estimates of R using remote-sensing techniques with sparse but direct rainfall observations. [source] Local dynamic changes in confined extracellular environments within organsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 10 2009Natasha Behrendorff Summary 1Herein we review past work that has studied the composition of luminal fluid in organs, with a focus on measures of calcium and pH in the exocrine glands. This luminal environment is ,external' to the mammalian body and is not subject to the usual mechanisms of homeostatic control. Instead, it is controlled by the behaviour of the cells that line the lumen. 2We discuss the likely possibility that rapid and local changes in calcium and pH occur within microdomains in the lumen. Further, we present preliminary evidence, using live cell imaging of intact pancreatic fragments, that supports the idea that pH changes do occur. Our evidence indicates that exocytosis of secretory granules in pancreatic acinar cells leads to a loss of protons from the granule and a subsequent local acidification of the lumen. 3These changes in luminal composition are placed in the context of diseases of the pancreas, such as cystic fibrosis and pancreatitis, both of which are known to result in perturbations of luminal fluid composition. [source] | |||||||||||||||||||