cssi/SciSciGPT-SciSciNet huggingface dataset:
Improving the etched/regrown GaAs interface by in-situ etching using tris-dimethylaminoarsenic

In this study we have investigated, for the first time, the morphological and electrical properties of the in-situ etched/regrown interfaces of GaAs and Al x Ga 1-x As using tris-dimethylaminoarsenic (TDMAAs) in a chemical beam epitaxy (CBE) chamber. The TDMAAs in-situ etching condition of GaAs is optimized according to the analysis of atomic force microscopy (AFM) and capacitance-voltage (C-V) carrier profiles. The TDMAAs etch rate of GaAs increases from 40 to 135 nm/h by increasing the substrate temperature from 550°C to 700°C, but the etched surface morphology of GaAs on a patterned substrate becomes rougher at higher etching temperatures. A smooth surface morphology of GaAs with an interface state density of 1.4 x 10 11 cm -2 can be obtained at a lower in-situ etching temperature of 550°C. TDMAAs is shown to be an effective and promising precursor for in-situ etching of GaAs, thus providing a clean etched/regrown interface for novel device applications.
Serial changes of cerebral glucose metabolism and caudate size in persons at risk for Huntington's disease.

• Objective. —To determine the rate of change of glucose metabolism and caudate size in persons at risk for Huntington's disease. Design. —Eighteen persons at risk for Huntington's disease had two positron emission tomographic glucose metabolic studies and two magnetic resonance imaging scans separated by 42 (±9) months. Setting. —Ambulatory research subjects at a teaching hospital with magnetic resonance imaging and positron emission tomographic technology. Subjects. —Seven of the individuals were Huntington' disease gene negative by testing at the polymorphic DNA loci D4S10, D4S43, and D4S125; the remainder were gene positive by genetic testing or onset of chorea after study entry. Interventions. —None. Outcome Measures. —Onset of chorea and imaging results. Results. —The gene-positive group demonstrated a significant 3.1 % loss of glucose metabolic rate per year in the caudate nucleus (95% confidence interval [CI], −4.64, −1.48) compared with the gene-negative group. There was a 3.6% per year increase in the magnetic resonance imaging bicaudate ratio (95% CI, 1.81, 5.37), a linear measure of caudate atrophy. The rate of change in caudate size did not correlate with the rate of change in caudate metabolism, suggesting that metabolic loss and atrophy may develop independently. Conclusions. —The results suggest that a reduction in caudate glucose metabolism and atrophy develop rapidly in Huntington's disease. The findings establish a strategy for using serial positron emission tomographic imaging to monitor experimental pharmacologic interventions in presymptomatic individuals who have developed caudate hypometabolism.
An Empirically Derived Classification of Parenting Practices

Cluster analysis was used to empirically determine if parenting practices would reflect distinct patterns of parental behavior in a sample of 1,056 mothers. Hierarchical agglomerative clustering was performed with J. H. Ward's (1963) method. R. Mojena's (1977) criterion determined that a 4-cluster solution was optimal; the resulting patterns are described. Simplified rules for classifying new cases also were generated. The clusters differentiated the mothers by age, education, number of children, socioeconomic status, and frequency of reported behavior problems. Theoretical and methodological issues, links to D. Baumrind's (1991) parenting styles, and the heuristic potential of classifying parenting practices are discussed.
Cognitive-behavioral group therapy for the depressed elderly: Issues and adaptations

The application of group cognitive-behavioral therapy to depressed geriatric outpatients is illustrated through case examples. Age changes in intellectual functioning may cause the therapy to proceed more slowly than expected and may make behavioral components the most useful aspects of the treatment for some people. Health status may affect the assessment of severity of depression as well as the pace of the treatment. Differences in cultural and educational experience may make it more difficult for the group to become cohesive. Passivity and negative stereotypes of aging need to be actively confronted.
Cell-Cell Interactions Mediate the Response of Vascular Smooth Muscle Cells to Substrate Stiffness

The vessel wall experiences progressive stiffening with age and the development of cardiovascular disease, which alters the micromechanical environment experienced by resident vascular smooth muscle cells (VSMCs). In vitro studies have shown that VSMCs are sensitive to substrate stiffness, but the exact molecular mechanisms of their response to stiffness remains unknown. Studies have also shown that cell-cell interactions can affect mechanotransduction at the cell-substrate interface. Using flexible substrates, we show that the expression of proteins associated with cell-matrix adhesion and cytoskeletal tension is regulated by substrate stiffness, and that an increase in cell density selectively attenuates some of these effects. We also show that cell-cell interactions exert a strong effect on cell morphology in a substrate-stiffness dependent manner. Collectively, the data suggest that as VSMCs form cell-cell contacts, substrate stiffness becomes a less potent regulator of focal adhesion signaling. This study provides insight into the mechanisms by which VSMCs respond to the mechanical environment of the blood vessel wall, and point to cell-cell interactions as critical mediators of VSMC response to vascular injury.
Variation in the utilization of reconstruction following mastectomy in elderly women

Background Regardless of their age, women who choose to undergo postmastectomy reconstruction report improved quality of life as a result. However, actual use of reconstruction decreases with increasing age. Whereas this may reflect patient preference and clinical factors, it may also represent age-based disparity.
Optimal tests for electroweak loop effects

A statistical analysis is given for the experimental precision necessary for establishing loop effects in the electroweak theory. Cases with three observables, gauge boson masses and the Weinberg angle, is analyzed by an optimised test. An information on the Weinberg angle with even 5% error (±.01 in sin2θW) is shown to reduce the requirement for the measurements of gauge boson masses significantly.
Effect of pH on continuous biohydrogen production from liquid swine manure with glucose supplement using an anaerobic sequencing batch reactor

pH is considered as one of the most important factors governing the hydrogen fermentation process. In this project, five pH levels, ranging from 4.4 to 5.6 at 0.3 increments, were tested to evaluate the pH effect on hydrogen production from swine manure supplemented with glucose in an anaerobic sequencing batch reactor system with 16 h of hydraulic retention time (HRT). The optimal hydrogen yield (1.50 mol H2/mol glucose) was achieved at pH 5.0 when the maximum production rate of 2.25 L/d/L was obtained. Continuous hydrogen production was achieved for over 3 weeks for pH 5.0, 4.7, and 4.4, with no significant methane produced. However, as pH increased to 5.3 and 5.6, methane production was observed in the biogas with concurrent reductions in hydrogen production, indicating that methanogens could become increasingly activated for pH 5.3 or higher. Acetate, propionate, butyrate, valerate, and ethanol were the main aqueous products whose distribution was significantly affected by pH as well.
Opioid partial agonist buprenorphine dampens responses to psychosocial stress in humans

Pre-clinical and clinical evidence indicates that opioid drugs have stress-dampening effects. In animal models, opioid analgesics attenuate responses to isolation distress, and in humans, opioids reduce stress related to anticipation of physical pain. The stress-reducing effects of opioid drugs may contribute to their abuse potential. Despite this evidence in laboratory animals, the effects of opioids on responses to psychosocial stress have not been determined in humans. Here we examined the effects of buprenorphine, a μ-opioid partial agonist used to treat opioid dependence and pain, on subjective and physiological responses to a stressful public speaking task in healthy adults. We hypothesized that buprenorphine would reduce subjective and physiological stress responses. Healthy adult volunteers (N=48) were randomly assigned to receive placebo, 0.2mg sublingual buprenorphine, or 0.4mg sublingual buprenorphine in a two-session study with a stressful speaking task (Trier Social Stress Test; TSST) and a non-stressful control task. During the sessions, the participants reported on their mood states, provided subjective appraisals of the task, and measures of salivary cortisol, heart rate, and blood pressure at regular intervals. Stress produced its expected effects, increasing heart rate, blood pressure, salivary cortisol, and subjective ratings of anxiety and negative mood. In line with our hypothesis, both doses of buprenorphine significantly dampened salivary cortisol responses to stress. On self-report ratings, buprenorphine reduced how threatening participants found the tasks. These results suggest that enhanced opioid signaling dampens responses to social stress in humans, as it does in laboratory animals. This stress-dampening effect of buprenorphine may contribute to the non-medical use of opioid drugs.
Next Generation Redshift Surveys and the Origin of Cosmic Acceleration

Cosmologists are exploring two possible sets of explanations for the remarkable observation of cosmic acceleration: dark energy fills space or general relativity fails on cosmological scales. We define a null test parameter $ϵ(k,a)\ensuremath{\equiv}{\ensuremath{\Omega}}_{m}^{\ensuremath{-}\ensuremath{\gamma}}d\mathrm{ln}﻿D/d\mathrm{ln}﻿a\ensuremath{-}1$, where $a$ is the scale factor, $D$ is the growth rate of structure, ${\ensuremath{\Omega}}_{m}(a)$ is the matter density parameter, and $\ensuremath{\gamma}$ is a simple function of redshift. We show that it can be expressed entirely in terms of the bias factor, $b(a)$, measured from cross correlations with cosmic microwave background (CMB) lensing, and the amplitude of redshift-space distortions, $\ensuremath{\beta}(k,a)$. Measurements of the CMB power spectrum determine ${\ensuremath{\Omega}}_{m0}{H}_{0}^{2}$. If dark energy within general relativity is the solution to the cosmic acceleration problem, then the logarithmic growth rate of structure $d\mathrm{ln}﻿D/d\mathrm{ln}﻿a={\ensuremath{\Omega}}_{m}^{\ensuremath{\gamma}}$. Thus, $ϵ(k,a)=0$ on linear scales to better than 1%. We show that in the class of modified gravity models known as $f(R)$, the growth rate has a different dependence on scale and redshift. By combining measurements of the amplitude of $\ensuremath{\beta}$ and of the bias, $b$, redshift surveys will be able to determine the logarithmic growth rate as a function of scale and redshift. We estimate the predicted sensitivity of the proposed SDSS III (BOSS) survey and the proposed ADEPT mission and find that they will test structure growth in general relativity to the percent level.
Automated writing evaluation: defining the classroom research agenda:

With the advent of English as a global language, the ability to write well in English across diverse settings and for different audiences has become an imperative in second language education programmes throughout the world. Yet the teaching of second language writing is often hindered by the great amount of time and skill needed to evaluate repeated drafts of student writing. Online Automated Writing Evaluation programmes have been developed as a way to meet this challenge, and the scoring engines driving such programmes have been analysed in a considerable array of psychometric studies. However, relatively little research has been conducted on how AWE is used in the classroom and the results achieved with such use. In this article, we analyse recent developments in automated writing evaluation, explain the bases on which AWE systems operate, synthesize research with these systems, and propose a multifaceted process/product research programme on the instructional use of AWE. We explore this emerging area of inquiry by proposing a range of potential questions, methodologies and analytical tools that can define such a research agenda.
Results of a phase I dose-escalation study using three-dimensional conformal radiotherapy in the treatment of inoperable nonsmall cell lung carcinoma.

BACKGROUND The objective of this study was to report the results of a Phase I dose-escalation study using three-dimensional conformal radiation therapy (3D-CRT) for the treatment of patients with nonsmall cell lung carcinoma (NSCLC). METHODS Between 1991 and 2003, 104 patients were enrolled for 3D-CRT at Memorial Sloan-Kettering Cancer Center. The median patient age was 69 years. Twenty-eight percent of patients had Stage I–II NSCLC, 33% of patients had Stage IIIA NSCLC, 32% of patients had Stage IIIB NSCLC, and 6% of patients had recurrent NSCLC. Induction chemotherapy was received by 16% of patients. Radiation was delivered in daily fractions of 1.8 grays (Gy) for doses ≤ 81.0 Gy and in daily fractions of 2.0 Gy for higher doses. Accrual at a dose level was complete when 10 patients received the intended dose without unacceptable acute morbidity. RESULTS After an incident of fatal acute radiation pneumonitis at the starting dose of 70.2 Gy, the protocol was modified to limit normal tissue complication probabilities (NTCP) to < 25%. The dose was then escalated from 70.2 Gy, to 75.6 Gy, 81.0 Gy, and 84.0 Gy, with at least 10 patients treated at each dose level. Unacceptable pulmonary toxicity occurred at 90.0 Gy. Subsequently, another 10 patients were accrued at the 84.0 Gy level with acceptable toxicity. Thus, 84.0 Gy was the maximum tolerated dose (MTD). The crude late pulmonary toxicity rate was 7%, the 2-year local control rate was 52%, the disease-free survival rate was 33%, and the overall survival rate was 40%. The median survival was 21.1 months. Overall survival was improved significantly in patients who received ≥ 80.0 Gy. CONCLUSIONS The MTD of 3D-CRT for NSCLC with an NTCP constraint of 25% was 84.0 Gy in the current study. There was a suggestion of improved survival in patients who received 80.0 Gy. Cancer 2005. © 2005 American Cancer Society.
Mixing and chemical effects in SIMS depth profiling the Si/SiO2 interface

Abstract Distortion of secondary ion profiles found previously when using a Cs beam (for Si − secondary ions at buried layers in Si which contain oxygen) have also been observed here for Si + ions at the SiO 2 /Si interface. Auger electron spectroscopy results show an increase in the Cs concentration at the interface, supporting the proposal that the artifact results from a changing Cs concentration at the interface. This effect dominates any interface broadening which may also occur by ion beam mixing as has been observed using inert gas ion bombardment.
Delaying or deterring entry A game-theoretic analysis

Abstract Few models in the entry literature consider interaction among potential entrants or how the incumbent can exploit this interaction. I present a predation model in which incomplete information about the incumbent gives each entrant an incentive to enter after others in order to observe what happens to them upon entry. The incumbent can exploit this incentive to delay entry. Thus the model leads to endogenous delayed entry, rather than entry deterrence only. The interaction of the entrants leads to surprising ambiguities. For example, lowering the incumbent's payoff to predation for all types can increase the probability of predation, slowing entry.
Influence of Model Complexity and Aeroelastic Constraints on Multidisciplinary Optimization of Wings

This investigation focuses on the performance of the Automated Structural Optimization System multidisciplinary optimization code in the structural weight optimized design of two e nite element models of a low-aspect ratio e ghter-type wing. Optimal designs for the wing with the structure represented by a coarse and a more complex e nite element model are obtained with constraints imposed on strength, aileron reversal, and e utter using subsonic and supersonic aerodynamic theories. The results demonstrate the ability of ASTROS to effectively e nd local minima with weight as the objective function. The trends in the e nal weights illustrate the impact of changing design constraints on optimal design.
One, two, three . . . infinity: lower bounds for parallel computation

In this paper we compare the power of the two most commonly used concurrent-write models of parallel computation, the COMMON PRAM and the PRIORITY PRAM. These models differ in the way they resolve write conflicts. If several processors want to write into the same shared memory cell at the same time, in the COMMON model they have to write the same value. In the PRIORITY model, they may attempt to write different values; the processor with smallest index succeeds.We consider PRAM's with n processors, each having arbitrary computational power. We provide the first separation results between these two models in two extreme cases: when the size m of the shared memory is small (m ≤ ne, e
Determination of uranium by flow injection inductively coupled plasma mass spectrometry

Abstract A flow injection (FI) system for the on-line determination of uranium in environmental samples has been characterized and tested. The simple FI manifold uses off-the-shelf components to precisely manipulate the carrier, sample, eluent, and washing streams through a column separation module. The separation module preconcentrates the sample by a factor of 30 and removes the potentially interfering environmental matrix. TRU TM , a commercially available resin for extraction chromatography, is packed into a glass separation column (5 × 50 mm) in the limited dispersion ( D = 2.8) FI system. Detection is performed by using inductively coupled plasma mass spectrometry (ICP-MS). Results are presented for the determination of 238 U in groundwater samples. The total analysis time for each 5.0-ml aqueous sample is 6 min. The detection limit for 238 U is 0.30 ng/l. By using certified groundwater samples, a precision of 1.1% ( n = 4) and accuracy of ± 1.8% for 238 U at 62.6 ng/l were observed. We also report the design and preliminary testing of a second FI-ICP-MS system that minimizes the influence of polyatomic ions (e.g., 238 UH + ) on the determination of minor actinides (e.g., 239 Pu + ) by ICP-MS.
Synthesis of isotopically labeled P-site substrates for the ribosomal peptidyl transferase reaction

Isotopomers of the ribosomal P-site substrate, the trinucleotide peptide conjugate CCA-pcb (Zhong, M.; Strobel, S. A. Org. Lett. 2006, 8, 55−58), have been designed and synthesized in 26−35 steps. These include individual isotopic substitution at the α-hydrogen, carbonyl carbon, and carbonyl oxygen of the amino acid, the O2‘ and O3‘ of the adenosine, and a remote label in the N3 and N4 of both cytidines. These isotopomers were synthesized by coupling cytidylyl-(3‘,5‘)-cytidine phosphoramidite isotopomers as the common synthetic intermediates, with isotopically substituted A-Phe-cap-biotin (A-pcb). The isotopic enrichment is higher than 99% for 1-13C (Phe), 2-2H (Phe), and 3,4-15N2 (cytidine), 93% for 2‘/3‘-18O (adenosine), and 64% for 1-18O (Phe). A new synthesis of highly enriched [1-18O2]phenylalanine has been developed. The synthesis of [3‘-18O]adenosine was improved by Lewis acid aided regioselective ring opening of the epoxide and by an economical SN2−SN2 method with high isotopic enrichment (93%). S...
Pyrolysis of vinylacetylene between 300 and 450°C

Vinylacetylene was pyrolyzed at 300–450°C in a packed and an unpacked static reactor with a pinhole bleed to a quadrupole mass spectrometer. The reactant and C8H8 products were monitored continuously during a reaction by mass spectrometry. In some runs, the products were also analyzed by gas chromatography after the run. In these runs CH4, C2H6, C3H6, and C2H4 were also detected. The reaction for vinylacetylene removal and C8H8 formation is homogeneous, second order in reactant, and independent of the presence of a large excess of N2 or He. However, C8H8 formation is about half-suppressed by the addition of the free-radical scavengers NO or O2. The rate coefficient for total vinylacetylene removal is 1.7 × 106 exp(−79 ± 13 kJ/mol RT) L/mol · s. The major reaction for C4H4 removal is polymerization. In addition four C8H8 isomers, carbon, and small hydrocarbons are formed. The three major C8H8 isomers are styrene, cyclooctatetraene (COT), and 1,5dihydropentalene (DHP). The C8H8 compounds are formed by both molecular and free-radical processes in a second-order process with an overall k ≃ 3 × 108 exp(−122 kJ/mol RT) L/mol · s (average of packed and unpacked cell results). The molecular process occurs with an overall k = 8.5 × 107 exp (−118 kJ/mol RT) L/mol · s. The COT, DHP, and an unidentified isomer (d), are formed exclusively in molecular processes with respective rate coefficients of 4.4 × 104 exp(−77 kJ/mol RT), 1.7 × 105 exp(−89 kJ/mol RT), and 3.1 × 109 exp(− 148 kJ/mol RT) L/mol · s. The styrene is formed both by a direct free-radical process and by isomerization of COT.
A rule-based model of human problem-solving behavior in dynamic environments

Human problem solving is considered with emphasis on situations involving human-machine interaction in detecting, diagnosing, and compensating for failures in engineering systems. An overall model is presented which considers the breath and robustness of human problem-solving behavior in dynamic environments typical of engineering systems. A realization of the general structure of this model within a particular rule-based computer program is discussed. In this program the human behavior in controlling a dynamic process is represented by a set of production rules. The selection of appropriate production rules for a given situation is performed by ordering the rules for specific tasks and by a control mechanism. The latter provides a means to access only a small part of the knowledge base at a time in order to derive decisions as opposed to searching the whole knowledge base. This program was applied to model human problem solving in a process control task. Results from comparing model and subject behavior are presented and discussed.
New software models thermodynamics of magmatic systems

A new software package, MELTS, is now available for modeling crystal-liquid equilibria in magmatic systems. MELTS is based on experimentally calibrated models for the thermodynamics of solution of magmatic liquids and solids [Ghiorso and Sack, 1994; Hirschmann and Ghiorso, 1994]. The package computes equilibrium phase assemblages—the compositions and proportions of coexisting liquids and solids—by direct minimization of the thermodynamic potential of the system [Ghiorso and Kelemen, 1987]. MELTS has a menu driven, interactive, graphical user interface and may be used to model a range of igneous processes including equilibrium or fractional crystallization of specified bulk compositions, crystallization paths under specified T-f02, total enthalpy, total entropy, or total volume constraints, and assimilation or magma mixing in evolving magmatic systems.
PHYSEAL RECONSTRUCTION USING TISSUE DONATED FROM EARLY POSTNATAL LIMBS IN A MURINE MODEL

Physeal reconstruction was performed in a murine model by transplanting corresponding postnatal tissue from 4-day-old C57B mice to resection defects. The site of the reconstruction, the murine distal femoral epiphysis, is completely cartilaginous and avascular at this stage of development. The tissue transplanted into the defect was demonstrated to have high kinetic activity by its incorporation of tritiated thymidine. The physeal reconstruction as performed restored only 25% of normal growth. While transplanting cell populations is feasible, the method will require a great deal of work before clinical application.
On theT(1) theorem on product domains

The direct proof by R. R. Coifman and Y. Meyer of theT(1) Theorem of G. David and J. L. Journe is based on the following result.
Amy Levy and Identity Criticism: A Review of Recent Work

Amy Levy was a fin-de-siecle poet, novelist, and essayist. While critically acclaimed within her lifetime, she was all but forgotten by literary scholars until the 1980s, when her work was reintroduced to scholars as part of a larger project to integrate the writings of women and other minority groups into the canon. Levy falls into a number of these minority categories: she was not only female but also Jewish, and expressed non-normative understandings of sexual desire. Virtually all critical work on Levy since her reappearance in the field has been deeply rooted in her experiences as an her concepts of minority identity. In this review article, I examine the ways in which recent critical works on Levy that refine and expand preceding identity criticism. I argue that articles and book chapters by Iveta Jusova, Cynthia Scheinberg, and Linda Hunt Beckman are setting the new standard for identity criticism by examining the complex intersections of identity categories, and by linking identity to new fields of inquiry.
A study of component surface refurbishment

The act of surface refurbishment of worn components is of itself both environmentally friendly and something which can be accomplished in a timely and convenient manner. It is environmentally friendly since it conserves both material and energy which would be otherwise expended in producing new components. It thus follows that it is also a convenient time-saver. There are many approaches to surface refurbishment, which include Laser Engineered Net Shaping (LENS), and weld repair, to name just two. All are likely to involve machining in the generation of the new surface. It is true to say that, indeed, most metallic surfaces will have experienced some degree of machining. This leads to the possibility that the properties of surfaces generated by machining are likely to be affected by their superficial state of stress and characteristics of the refurbished layer. Therefore our proposed research is in the characterization of the machinability of the remanufactured surface and the subsequent component performance. Such characteristics include fatigue, corrosion and oxidation.
Fluorescence-enhancement sensing of ammonia and hydrazines via disruption of the internal hydrogen bond in a carbazolopyridinophane

Abstract A carbazolopyridinophane has been designed and prepared, with an internal N H⋯N hydrogen bond between the carbazole and pyridine rings. This hydrogen bond causes the fluorescence of the carbazole unit to be substantially quenched. In heptane solution, addition of ammonia or simple hydrazines disrupts the internal hydrogen bond and restores fluorescence, within 1–5 min. Signal intensity varies linearly with guest concentration; concentrations of ammonia or hydrazines down to 100 ppb have been measured.
General approach for the synthesis of polyquinanes. Facile generation of molecular complexity via reaction of 1,2-dicarbonyl compounds with dimethyl 3-

Abstract The condensation of dimethyl 3-ketoglutarate 1 with 1,2-dicarbonyl compounds provides access to the polyquinane derivatives tricyclo[6.3.0.01,5] undecane - 3,7.9 - trione 27, tricyclo [3 3 3 01,5]undecane 31; tetra-cyclo [5.5.1.04,13.010,13] - tridecane - 2,6,8,12 - tetraone 41; tetracyclo[6.6.0.01,5. 08,12] tetradecane - 2,7,9,14 - tetraone 44, and the tetracyclo[5.5.1.010,13]tridecane triones 5b and 6b. The unique structure of staurane tetraone 41 has resulted in spontaneous resolution of the two antipodes on crystallization from DMF. In addition, examination of the crystal structures of tetraones 41 and 44, in terms of strain energy, coupled with the steric accessibility of the β-diketone functionality contained in 41 and 44 have been employed to explain why tetraone 44 and trione 27 undergo a retro-Claisen reaction (CH3OH) more rapidly than staurane tetraone 41.
Microzooplankton distribution, dynamics, and trophic interactions relative to phytoplankton and quagga mussels in Saginaw Bay, Lake Huron

Abstract Invasive quagga mussels have recently replaced zebra mussels as the dominant filter-feeding bivalves in the Great Lakes. This study examined microzooplankton (i.e., grazers Microcystis and diatom blooms, respectively. Feeding on microzooplankton could buffer mussels during lean periods, or supplement other consumed resources, particularly during noxious cyanobacterial blooms. The results of this study demonstrate that microzooplankton are a resilient and critical component of the Saginaw Bay ecosystem.
Replacement of the Escherichia coli trp operon attenuation control codons alters operon expression

To test features of the current model of transcription attenuation in amino acid biosynthetic operons, alterations were introduced into the trp operon leader region and expression of the mutated operons was examined in miaA and miaA+ Escherichia coli strains that lacked the trp repressor. The miaA mutation prevents modification of the adenosine residue immediately 3' of the anticodon of tRNAs that interact with codons beginning with uridine. The undermodified tRNA(Trp) in miaA strains is thought to increase readthrough at the trp attenuator by slowing ribosome movement over two tandem Trp codons in the 14-codon leader peptide coding region. The rate of translation of these two "control codons" is thought to be the key step in determining the extent of transcription attenuation in the trp leader region. Sequential deletion of trpL DNA specifying the leader peptide initiation region, RNA segment 1, RNA segment 2 and RNA segment 3 alternately decreased and increased trp operon expression, a result consistent with previous findings in another bacterium and the generally accepted model for transcription attenuation. Replacement of the tandem Trp control codons by AGG-UGC (Arg-Cys) codons eliminated the miaA-dependent increase in transcription readthrough. Replacement of the Trp control codons by AGG-UGA (Arg-stop) codons caused complete readthrough at the trp attenuator as well as abolishing the miaA effect. Presumably, the ribosome terminating translation at the new UGA codon mimics the effect of a stalled ribosome at the Trp control codons. This finding suggests that ribosome dissociation at some stop codons is slow relative to the time required for transcription of the trp leader region. Thus, most ribosomes translating the trp leader peptide coding region may remain attached to the natural UGA stop codon until after the attenuation decision is made. The interpretation supports models for trp operon attenuation in which the elevated basal level readthrough is determined by occasional ribosome release prior to synthesis of the 3:4 terminator hairpin.
Perceptions and Effects of a System's Usability by Experience Level

This study compared users' self-reported and observed usability problems within a Web-based information system, based on their experiences with the system. Eighteen employees of a company which created the system were chosen to represent typical end-users. Each participant was asked to complete a specific list of tasks within the system, after which he or she answered several questions regarding the system's usability. While advanced users generally completed the tasks in less time than novices, the number of tasks completed correctly and the number of usability problems reported did not differ significantly by experience level. Problems identified by the participants reflected accepted usability guidelines, suggesting that, by following user-centered design principles, such problems can be avoided in future development efforts.
Picosecond standoff multiphoton detection of gas phase species : initial results

In the implementation of laser-induced fluorescence (LIF) for the detection of vapor-phase organic compounds that accompany hazardous materials, multiphoton excitation offers a significant advantage over single photon methods. In particular, if the absorption spectra of unwanted background molecules overlap that of the target molecule, single photon LIF is plagued by false positives. Multiphoton methods alleviate this difficulty by requiring that the target molecule be in resonance with multiple molecular transitions. A promising multiphoton method is stimulated Raman adiabatic passage (STIRAP). This method involves a counterintuitive sequence of laser pulses which is capable of transferring 100% of the target molecules to the desired excited state from which fluorescence is to be observed. As a precursor to more complex molecules, we demonstrate the STIRAP technique on sodium vapor using the 3p ( 2 P 1/2 ) ← 3s ( 2 S 1/2 ) and 5s ( 2 S 1/2 ) ← 3p ( 2 P 1/2 ) transitions. This is the first time STIRAP has been achieved on a vapor using picosecond lasers. We produced light to couple the states using two synchronously pumped OPG/OPAs (pumped by the 355 nm light from a picosecond YAG). We measured the fluorescence from the 5s state to both 3p states ( 2 P 1/2 , 2 P 3/2 ) and from both 3p states to the 3s state with monochromator using a gated CCD to eliminate Rayleigh scattered light. Our results indicate a four to five-fold increase in the transfer efficiency to the 5s state when the laser pulse that couples the 3p and 5s states precedes the laser pulse tuned to the 3p ← 3s transition.
Thermal inactivation of butyrylcholinesterase and acetylcholinesterase.

Differences were observed in the extent of thermal inactivation of human butyrylcholinesterase (BuChE) and eel acetylcholinesterase (AChE). BuChE was more resistant to 57°C inactivation than was AChE. Thermal inactivation of BuChE was reversible and followed first-order kinetics. AChE thermal inactivation was irreversible and did not follow first-order kinetics. AChE was marginally protected from thermal inactivation by the “nonspecific salts” ammonium sulfate and sodium chloride and to a greater extent by the “active site-specific salts” choline chloride, sodium acetate, and acetylcholine iodide. This protection was accompanied by a loss of absorbance at 280 nm. This data supports the hypothesis that thermal inactivation of AChE occurs by conformational scrambling and that aromatic amino acid residue(s) are involved in this process.
Cognitive Processing of High-Functioning Autistic Children: Comparing The K-ABC and the WISC-R

The K-ABC was administered to 21 autistic children, and scores were examined both in relation to differences in sequential and simultaneous processing scores and in comparison to the subjects' curr...
ORIGIN, DEVELOPMENT, AND NATURE OF INTRANUCLEAR RODLETS AND ASSOCIATED BODIES IN CHICKEN SYMPATHETIC NEURONS

Correlative data are presented here on the developmental history, dynamics, histochemistry, and fine structure of intranuclear rodlets in chicken sympathetic neurons from in vivo material and long-term organized tissue cultures. The rodlets consist of bundles of ∼70 ± 10 A proteinaceous filaments closely associated with ∼0.4–0.8 µ spheroidal, granulofibrillar (gf) bodies of a related nature. These bodies are already present in the developing embryo a week or more in advance of the rodlets. In early formative stages rodlets consist of small clusters of aligned filaments contiguous with the gf-bodies. As neuronal differentiation progresses these filaments increase in number and become organized into well-ordered polyhedral arrays. Time-lapse cinemicrography reveals transient changes in rodlet contour associated with intrinsic factors, changes in form and position of the nucleolus with respect to the rodlet, and activity of the gf-bodies. With the electron microscope filaments may be seen extending between the nucleolus, gf-bodies, and rodlets; nucleoli display circumscribed regions with fine structural features and staining reactions reminiscent of those of gf-bodies, We suggest that the latter may be derivatives of the nucleolus and that the two may act together in the assemblage and functional dynamics of the rodlet. The egress of rodlet filaments into the cytoplasm raises the possibility that these might represent a source of the cell's filamentous constituents.
Geometrically Nonlinear Theory of Initially Imperfect Sandwich Curved Panels Incorporating Nonclassical Effects

A comprehensive geometrically nonlinear theory of initially imperfect doubly curved sandwich shells is developed. The theory encompasses sandwich structures with dissimilar face sheets constructed of laminate composites and with the core modeled as an orthotropic body featuring strong or soft behaviors. The theory includes the dynamic as well as the temperature and moisture effects. As a special case, a range of related applications of the theory of sandwich shells with soft core are presented. These involve the buckling and postbuckling of flat and circular cylindrical shells compressed by uniaxially edge loads, and the influence played in this respect by a number of geometrical and physical parameters is highlighted. Also contained are comparisons of buckling results obtained in the context of the present theoretical model with the ones obtained experimentally, and reasonable agreements are reported.
America still fighting the cold war in an era of global terrorism

Purpose – The Second World War and the cold war led to a revolution in military affairs, but this article seeks to question whether the USA is equipped to respond to future conflicts in an age of global terrorism.Design/methodology/approach – The article considers recent conflicts in Afghanistan and Iraq, as well as the tactics of terrorist groups, to explore how America's military forces should adapt to future needs, particularly in terms of technology and strategy.Findings – The USA faces a military dilemma. The force numbers and the technology mix needed to cope with terrorist and insurgency warfare are currently insufficient. However, the overall US budget is too high, and defense expenditures are one of the principal causes.Originality/value – Contributes to the debate on countering global terrorism.
Asymptotic error estimates for perturbations of linear elliptic problems on nonsmooth domains

In a series of papers, we give quantitative and qualitative error analysis for effects of mathematical idealizations on solutions of boundary value problems. This paper is devoted to qualitative error estimates for perturbations of linear elliptic boundary value problems on nonsmooth domains. The perturbations are restricted on small sets near corners.
Flecked-Retina Syndromes

A number of retinal disorders may present with fleck-like lesions in the retina. We describe the case of a 13-year-old girl who presented with a complaint of decreased vision and prior diagnosis of "fleck-retina." Further examination revealed that the patient had an autosomal recessive disorder associated with systemic manifestations. In the current article, the authors describe the case report and briefly review the various autosomal-recessive disorders that may present with "retinal flecks."
Obesity and elevated plasma leptin concentration in oMT1A-o growth hormone transgenic mice.

OBERBAUER, A. M., JONATHAN A. RUNSTADLER, JAMES D. MURRAY, AND PETER J. HAVEL. Obesity and elevated plasma leptin concentration in oMT1A-o growth hormone transgenic mice. Objective: This study was undertaken to evaluate plasma leptin concentration in the regulatable ovine metallothionein-ovine growth hormone (oMT1a-oGH) transgenic (TG) mouse model of obesity. Research Methods and Procedures: Transgene stimulus (zinc) was provided at 21 days of age to male and female wild-type (WT) and TG mice. Plasma leptin concentrations were measured by radioimmunoassay at 42, 63, 84, and 105 days of age and from inactivated TG mice at 84 and 105 days. Results: WT and TG mice did not differ significantly in plasma leptin concentration at any of the ages examined (42, 63, 84, and 105 days), although females showed consistently higher plasma leptin concentrations than males regardless of genotype throughout the duration of the study. Male and female TG mice in which the transgene was inactivated at 63 days had a 1.5-fold to 3.5-fold increase in plasma leptin concentration over WT mice and continuously activated TG mice at 84 and 105 days of age. The elevated plasma leptin concentration seen in the inactivated TG mice at 84 and 105 days of age reflects the >300% increase in white adipose tissue seen in this model and correlated with all adipose depot weights and overall body lipid at these later ages. When plasma leptin was expressed per gram of total body fat, the leptin adjusted for body lipid was significantly higher in WT mice than either continuously activated TG or activated and then inactivated TG groups. Discussion: The inactivated TG mice in this study had higher plasma leptin levels with increasing total body adiposity, but the relative proportion of circulating leptin, on a total body lipid basis, was reduced when compared with the WT mice. This reduction was also observed in activated TG mice at the older ages. Although the absolute levels of circulating leptin were elevated in the inactivated TG animals, the amount of leptin produced per gram of fat was lowered. With the inactivation of the transgene, the leptin remained depressed after the removal of the elevated growth hormone. This represents a potential explanation for the ensuing hypertrophy of the fat depots and the abnormal phenotypic response of inactivated TG mice to elevated plasma leptin concentrations resulting in the development of obesity.
Nuclear volume and chromatin conformation of small and large bovine luteal cells: effect of gonadotropins and prostaglandins and dependence on luteal phase.

Change in nuclear volume and chromatin conformation are generally considered to reflect altered gene expression in eukaryotic cells. The present studies were undertaken to investigate whether these nuclear parameters of luteal cells can be altered by hormone treatment in vitro or change during the estrous cycle. The nuclear volume of small luteal cells was significantly lower than that of large luteal cells during the cycle and pregnancy. The nuclear volumes of small and large luteal cells from pregnancy did not change during incubation without any hormone or with 10 nM prostaglandin (PG)F2α. However, incubation with 1 nM human chorionic gonadotropin (hCG) or 10 nM PGE1 resulted in a significant increase of nuclear volume of small luteal cells by 4 h and that of large luteal cells by 6 h. Small cells were more responsive to hCG than large luteal cells. The nuclear volumes of small and large luteal cells also significantly increased from early to mid luteal phase with no further change in late luteal phase. hCG and PGE1, as well as PGF2α, treatment resulted in a change of chromatin conformation of small and large luteal cells. Dibutyryl cyclic AMP (10 mM) mimicked the hormones by increasing nuclear volumes and changing the chromatin conformation of small and large luteal cells. Chromatin conformation of small and large luteal cells also changed from early to mid luteal phase and mid to late luteal phase. In conclusion, in vitro, hCG and PGs can regulate nuclear volume and/or chromatin conformation of small as well as large bovine luteal cells. In vivo, these nuclear changes occur during the periods of luteal growth, development and regression in the estrous cycle.
Stochastic optimization formulations for reliability unit commitment runs

To address the uncertainties caused by the penetration of intermittent renewable energy, most ISOs/RTOs perform day-ahead and look-ahead reliability unit commitment (RUC) runs, ensuring sufficient generation capacity available in real time to accommodate the uncertainties. Two-stage stochastic optimization models have been studied extensively to strengthen the RUC runs, while multi-stage stochastic optimization models were barely studied. In this paper, we investigate the unit commitment and economic dispatch decision differences generated by these two approaches considering the load uncertainties in the system. The stochasticity is represented by a set of scenarios for the two-stage model and a scenario tree for the multi-stage case.
A framework to categorize students as learners based on their cognitive practices while learning differential equations and related concepts

There are numerous theories that offer cognitive processes of students of mathematics, all documenting various ways to describe knowledge acquisition leading to successful transitions from one stage to another, be it characterized by Dubinsky's encapsulation, Sfard's reification or Piaget's equilibration. We however are interested in the following question. Who succeeds at making the leap and can we describe the attributes that set them apart from the ones that do not? In this article, we offer a framework to categorize students as learners based on their individual approaches towards learning concepts in differential equations and related concepts – as demonstrated by their efforts to resolve a conflict, conserve and rebuild their cognitive structures.
Building community, legitimating consumption: creating the U.S. bicycle market, 1876–1884

Economic and organizational sociologists tend to define markets as sets of producers, and research mostly supply-side issues. They generally ignore the role of consumers and their use of products, the source of profit for producers, a neglect especially problematical with regard to understanding market creation. A definition of markets as 'producers and consumers of a product' highlights the efforts to organize and legitimate product use that consumers, as well as producers, must undertake to help create markets. Much of this organization and legitimation involves setting up networked communities of producer and consumer organizations, which are also devoted to practical support of product use. In this article I trace the history of the early U.S. bicycle market to show how producers and consumers worked with each other and separately to organize and to confer legitimacy on product use, which supported the market.
A Parametric Down-Conversion Source for Two-Photon Absorption Experiments

We describe a Parametric Down-Conversion source based on a low-power (< 1mW), narrowband (<1 MHz) fiber-coupled pump laser. The source is designed for two-photon absorption experiments related to quantum Zeno gates.
Learning disability and family dynamics: A mutual interaction

(1976). Learning disability and family dynamics: A mutual interaction. Journal of Clinical Child Psychology: Vol. 5, Beyond Child Watching, pp. 35-40.