cssi/SciSciGPT-SciSciNet huggingface dataset:
Spontaneous emission of bloch oscillation radiation from a single energy band

A theory for the spontaneous emission of radiation for a Bloch electron traversing a single energy band under the influence of a constant external electric field is presented. The constant external electric field is described in the vector potential gauge. The quantum radiation field is described by the free space quantized electromagnetic field in the Coulomb gauge. The instantaneous eigenstates of the Bloch Hamiltonian are introduced as basis states to analyze the Bloch dynamics to all orders in the constant external electric field. The radiation field described by the quantized electromagnetic field provides the vacuum fluctuations that are responsible for the spontaneous emission of radiation of the single electron from the upper regions of the energy band. It is shown that the spontaneous emission occurs with frequencies equal to integral multiples of the Bloch frequency without any ad hoc assumptions made concerning the existence of Wannier-Stark ladder levels. An explicit expression for the spontaneous emission transition probability is derived to first order in the quantized radiation field; results show the explicit dependence upon the electron energy band structure, photon polarization, and the directionality of the radiation output. As an illustration, spontaneous emission probabilities are developed and illustrated for nearest-neighbor tight-binding and more realistic superlattice band structure models. For the GaAs-based superlattices, the power radiated into free space from spontaneous emission due to Bloch oscillations in the terahertz frequency range is estimated to be about one-tenth of a microwatt.
Cumulation and Cultural Processes

IN SOME statements about the nature of culture, culture is characterized as being cumulative (Goldenweiser 1937:45; Hoijer 1953:556; Kroeber 1948:297; White 1949:374, 398). In other statements only certain aspects of culture are said to be cumulative-e.g., science and technology (Kroeber 1952: 151). In still other statements a distinction is made between "culture" and "civilization." According to this distinction, culture is usually considered to be subjective, unique, and noncumulative; and civilization is considered to be objective, cumulative, and irreversible (cf. MacIver 1931:227-28; Thurnwald 1950; Weber 1939:25-26). The differences in the foregoing statements indicate that the matter of cumulation in culture needs additional clarification.
Neutralization‐reionization study of C6H6O isomers

Neutralization-reionization (+NR+) mass spectrometry is employed to examine the behavior of C6H6O isomers in the gas phase. Phenol and cyclohexa-2,4-dienone are found not to interconvert following neutralization with mercury of their corresponding cation radicals at 9.9 keV kinetic energy. A very low extent of isomerization is observed following collisional activation of fast C6H6O neutrals with helium. The +NR+ and collisionally activated dissociation spectra, the latter obtained at unit mass resolution, are used to identify these [C6H6O]+ ˙ isomers. Hexa-1,3,5-trienal is found to cyclize spontaneously to cyclohexa-2,4-dienone during attempted pyrolytic preparation. The thermochemistry of these C6H6O molecules and cation radicals is discussed on the basis of experimental data and MNDO calculations.
Excess molar enthalpies and the thermodynamics of (methanol + water) to 573 K and 40 MPa

Abstract Excess molar enthalpies H m E of (methanol + water) were measured from 298 to 573 K at pressures from 7 to 40 MPa. The observed H m E s are significantly negative at 298.15 K, near zero at about 398 K, and positive at higher temperatures. The composition dependence of H m E at low temperatures is much simpler than for (ethanol or propanol + water). The measurements reported here extend above the critical temperature of methanol. The very large changes in H m E with temperature and composition often observed near the critical conditions of the more volatile component were not observed under the conditions of this study. The results reported here were combined with available measured values of other thermodynamic quantities and represented with thermodynamically consistent empirical functions of temperature, pressure, and composition. Calculated excess molar Gibbs free energies, excess molar volumes, excess molar enthalpies, and excess molar heat capacities are tabulated.
Isochronization Calculations for the Indiana University Cyclotron

A series of calculations using measured magnetic fields has been performed to determine the optimal gradient coil currents for the wide range of operating conditions to be experienced by the Indiana University main stage cyclotron. Depending on the particle type to be accelerated and final energy desired, the required radial field increase varies from 0.5% to 22%. An iterative least squares fitting technique is used to minimize orbit time variations. For the acceleration of 200 MeV protons (330 revolutions, fourth harmonic) the maximum phase excursion is predicted to be less than two rf degrees. The technique used can be adapted to using measured phase histories to predict corrections to gradient coil currents.
Modulation of the B cell response to T-independent antigens by prostaglandins: Evidence for effector system cross-talk

The extracellular environment is a major factor in determining the responsiveness of a cell to particular stimuli. For example, E series prostaglandins suppress B cell responses to T-independent antigens, mitogen stimulation of DNA synthesis and proliferation, and the primary immune response. We investigated the effects of prostaglandins on the intracellular signals generated by receptor-coupled effector systems in B lymphocytes. Pretreating splenocytes from athymic nude mice with forskolin, PGE1, or PGE2 decreased the magnitude of anti-IgM-induced changes in cytosolic free [Ca2+]. Addition of 8-Br-cAMP, forskolin, PGE1, or PGE2 following stimulation with anti-IgM resulted in a decrease in the intracellular calcium signal measured by fluorescence-activated cell sorting using Indo-1 as a Ca2+ indicator. This decrease was not a result of an inhibition of influx across the plasma membrane. Thus activation of adenylate cyclase by prostaglandins modifies the generation of signals by phosphoinositidase C. This effector system cross-talk between adenylate cyclase and phosphoinositidase C is consistent with and may account for the inhibitory effects of prostaglandins in B cell responses.
Meeting Reports: BioCD-2005 Workshop

An intensive weeklong course on Circular Dichroism (CD) was presented at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory (BNL), from June 20-24, 2005. CD is the difference in absorption of left and right circularly polarized light. It is observed in the spectral regions of absorption of molecules that are chiral, i.e., lacking a center of symmetry. While most CD spectra are small—only a tiny fraction of the total absorption biopolymers with helical structures—such as proteins, DNA, RNA and polysaccharides, exhibit informative CD spectra. The objective of BioCD-2005 was to acquaint the participants with the theory of ultraviolet CD spectroscopy.
Study of iron oxide nanoparticles in soil for remediation of arsenic

There is a growing interest in the use of nanoparticles for environmental applications due to their unique physical and chemical properties. One possible application is the removal of contaminants from water. In this study, the use of iron oxide nanoparticles (19.3 nm magnetite and 37.0 nm hematite) were examined to remove arsenate and arsenite through column studies. The columns contained 1.5 or 15 wt% iron oxide nanoparticles and soil. Arsenic experiments were conducted with 1.5 wt% iron oxides at 1.5 and 6 mL/h with initial arsenate and arsenite concentrations of 100 μg/L. Arsenic release occurred after 400 PV, and 100% release was reached. A long-term study was conducted with 15 wt% magnetite nanoparticles in soil at 0.3 mL/h with an initial arsenate concentration of 100 μg/L. A negligible arsenate concentration occurred for 3559.6 pore volumes (PVs) (132.1 d). Eventually, the arsenate concentration reached about 20% after 9884.1 PV (207.9 d). A retardation factor of about 6742 was calculated indicating strong adsorption of arsenic to the magnetite nanoparticles in the column. Also, increased adsorption was observed after flow interruption. Other experiments showed that arsenic and 12 other metals (V, Cr, Co, Mn, Se, Mo, Cd, Pb, Sb, Tl, Th, U) could be simultaneously removed by the iron oxide nanoparticles in soil. Effluent concentrations were less than 10% for six out of the 12 metals. Desorption experiment showed partial irreversible sorption of arsenic to the iron oxide nanoparticle surface. Strong adsorption, large retardation factor, and resistant desorption suggest that magnetite and hematite nanoparticles have the potential to be used to remove arsenic in sandy soil possibly through in situ techniques.
Body-size estimations in children six through fourteen: a longitudinal study.

Estimates of perceived and ideal body size were collected in 216 boys and girls ages 6 through 14 years. Video methodology was used to adjust the width of a life-size frontal image of the children. Longitudinal data were collected annually for three years, beginning at ages 6, 9, and 12. Three psychological methods were used, including the method of adjustment, staircase method, and adaptive probit estimation technique which permitted separate measures of the children's point of subjective equality and just noticeable difference values. The point of subjective equality is the body size which is subjectively equal to the child's perception of self. The just noticeable difference is the amount of change in body size necessary to detect the difference 50% of the time. Acceptable size boundaries were also measured, using the method of adjustment. Over-all, children were accurate in estimating their body width, with average overestimation of less than 2%. Overestimation decreased within each age group during t...
Fitting peaks with very low statistics

Abstract Commonly used least-squares fitting procedures can lead to strongly biased results when fitting peaks with very low statistics. The problem has been identified as being due to large statistical fluctuations in the data, leading to large variations in the weights used for the fit. Several modifications to the least-squares method are investigated for efficiency in eliminating the bias. These are tested on a set of gamma-ray spectra constructed in the laboratory and variously summed so as to give results with statistics increasing from very low to good. Three-point averaging or five-point smoothing of the data for calculating the weights are found to give consistent, unbiased results on these data. Other modifications of the least-squares method are shown to give less satisfactory results. When applicable, a simple “hand analysis” gives more consistent results than any of the fitting methods.
Toxic effect of the bloom-forming Trichodesmium sp. (Cyanophyta) to the copepod Acartia tonsa.

The toxicity of the marine cyanobacterium Trichodesmium sp. to the copepod Acartia tonsa was assessed in a series of experiments during a Trichodesmium bloom off the North Carolina coast in late October 1992. Healthy intact cells of Trichodesmium sp. were not toxic to A. tonsa and were ingested by A tonsa when no other foods were available. However, homogenized Trichodesmium cells were toxic to A. tonsa, suggesting that Trichodesmium sp. contains certain type(s) of intracellular biotoxins. This hypothesis was consistent with the observed high mortality when A. tonsa was treated with aging Trichodesmium sp. cells or with filtered cell homogenate. The affected copepods showed weakness, recumbency, and reduced responsiveness. Many were observed to have distended intestines. Bioassays using aged Trichodesmium sp. cells and filtered homogenate demonstrated a dose-dependent effect on A. tonsa survival. © 1994 Wiley-Liss, Inc.
An assessment of SARE-funcled farmer research on sustainable agriculture in the north central U.S.

Emergent research shows how some farmer groups in the United States are gaining visibility as a critical knowledge community, making important contributions to the ecological health and overall sustainability of the natural resource base. This study focuses on funded farmer research projects in the north central region, to analyze the process and outcome of local inquiry embodied in the discursive contents of reports to a funding agency, the U.S. Department of Agriculture's Sustainable Agriculture Research and Education program. The analyses suggest that farmers' locality-specific agricultural practices may constitute a reflective and learning community, generating local knowledge keenly attuned to an underlying value system that supports actions towards sustainability.
Superconducting magnet system for a space-based 100 MW MHD disc generator

The conceptual design is described for a 6-T superconducting magnet system for a space-based 100-MW single-coil magnetohydrodynamic disk generator. Overall cold-mass dimensions are 2.325-m diameter by 0.15-m thickness. Average current density in the winding is 1.8*10/sup 8/ A/m/sup 2/. Stored energy is 45 MJ, and total weight for the system with a 600-MPa in-structure stress is 500 kg. >
HAIR-LOSS SYNDROME IN BLACK-TAILED DEER OF THE PACIFIC NORTHWEST

A widespread hair-loss syndrome (HLS) has affected Columbian black-tailed deer (Odocoileus hemionus columbianus) in western Oregon and Washington (USA) since 1996. In order to better characterize the condition, 21 HLS-affected black-tailed deer (BTD) were necropsied, and body condition, parasite burdens, and significant lesions were noted. All deer were in poor body condition, and at least 17 had severe internal parasite burdens. A consistent finding was the presence of large numbers of chewing lice, identified as an indeterminate species of Damalinia (Cervicola). Four animals were infested with intrafollicular Demodex sp., the first report of this genus of mites in BTD. We postulate that the hair loss is largely due to ectoparasitism by a species of chewing louse that represents a new pathogen for BTD. This loss of pelage also may be an important contributor to the poor body condition of these animals.
Archaeological planning at Parris island Santa Elena national landmark

Since the establishment of the Marine Corps Recruit Depot, Parris Island, the command has been dealing with an archaeological site that dates from 1562 that contains the remains of Spanish and French colonial settlements. Known as the Santa Elena/Charlesfort site, the area has been under excavation since the early 1920s. Because of its importance to the colonial history of the United States, the site has been designated a national landmark. Besides its cultural importance, the site has also served as a learning tool for the Depot in its care and handling of cultural resources. © 2003 Wiley Periodicals Inc.
Thermodynamic equilibrium calculations of hydrogen production from the combined processes of dimethyl ether steam reforming and partial oxidation

Abstract Thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the combined processes of dimethyl ether (DME) partial oxidation and steam reforming were investigated as a function of oxygen-to-carbon ratio (0.00–2.80), steam-to-carbon ratio (0.00–4.00), temperature (100 °C–600 °C), pressure (1–5 atm) and product species. Thermodynamically, dimethyl ether processed with air and steam generates hydrogen-rich fuel-cell feeds; however, the hydrogen concentration is less than that for pure DME steam reforming. Results of the thermodynamic processing of dimethyl ether indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 °C, oxygen-to-carbon ratios greater than 0.00 and steam-to-carbon ratios greater than 1.25 at atmospheric pressure ( P = 1 atm). Increasing the operating pressure has negligible effects on the hydrogen content. Thermodynamically, dimethyl ether can produce concentrations of hydrogen and carbon monoxide of 52% and 2.2%, respectively, at a temperature of 300 °C, and oxygen-to-carbon ratio of 0.40, a pressure of 1 atm and a steam-to-carbon ratio of 1.50. The order of thermodynamically stable products (excluding H 2 , CO, CO 2 , DME, NH 3 and H 2 O) in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n -propanol, ethylene, ethanol and methyl-ethyl ether; trace amounts of formaldehyde, formic acid and methanol are observed. Ammonia and hydrogen cyanide are also thermodynamically favored products. Ammonia is favored at low temperatures in the range of oxygen-to-carbon ratios of 0.40–2.50 regardless of the steam-to-carbon ratio employed. The maximum ammonia content (i.e., 40%) occurs at an oxygen-to-carbon ratio of 0.40, a steam-to-carbon ratio of 1.00 and a temperature of 100 °C. Hydrogen cyanide is favored at high temperatures and low oxygen-to-carbon ratios with a maximum of 3.18% occurring at an oxygen-to-carbon ratio of 0.40 and a steam-to-carbon ratio of 0.00 in the temperature range of 400 °C–500 °C. Increasing the system pressure shifts the equilibrium toward ammonia and hydrogen cyanide.
Abnormalities in glucose regulation associated with mental illness and treatment

Several major mental illnesses, including depression, schizophrenia, Alzheimer’s dementia and bipolar affective disorder have been associated with impaired glucose regulation and elevated rates of diabetes mellitus [1]. The risk factors and underlying causes for developing diabetes mellitus in the setting of a preexisting mental illness, or for developing a mental illness in the setting of preexisting diabetes mellitus, are incompletely understood. In the past several years, investigators have begun to focus on some of the disease, lifestyle and treatment factors that may contribute to this important comorbidity. Research in this area has also begun to stimulate clinical efforts to improve the identification and management of patients who suffer from these combined disease processes. Of the mental disorders associated with diabetes, depression and schizophrenia are clinically important and wellstudied disorders that affect significant portions of the population. Major depressive disorder is thought to affect approximately 6% of the population at some time in their lives and is associated with recurrence and intermittent or chronic treatment with antidepressant medications. Schizophrenia affects approximately 1% of the population and typically has a young adult age of onset. This is usually a chronic condition, punctuated by acute psychotic exacerbations and often requires lifetime treatment with antipsychotic medications. Due to high rates of depression in schizophrenia, as well as a growing trend toward polypharmacy in this practice setting, many patients with schizophrenia are treated with combinations of antipsychotic agents, antidepressants and other agents. Complicating our understanding of the association between diabetes and mental illnesses are reports indicating that many of the medications used to treat conditions such as depression and schizophrenia can contribute to changes in whole-body glucose metabolism. Reviewed below, for example, antipsychotic medications may contribute to exacerbations of existing types 1 and 2 diabetes, new onset cases of type 2 diabetes, dyslipidemia (e.g., hypertriglyceridemia) and cases of metabolic acidosis or ketosis. Clinically important questions, including the identification of risk factors and underlying mechanisms, appropriate screening and prevention approaches, and optimal treatment, all remain to be answered. Proposed mechanisms of action for medication effects on glucose metabolism will be briefly reviewed.
LSD-potentiated apomorphine hypermotility: a model for differentiating antipsychotic drugs.

Abstract The model of LSD-potentiated apomorphine hypermotility (LPAH) in rats in comparison to apomorphine-induced hypermotility (AH) was used to investigate typical and atypical neuroleptics by analyzing complete dose response curves. Haloperidol (0.06 mg/kg) induced a parallel shift to the right of both the AH and LPAH dose response curves indicating dopaminolytic properties without any serotonolytic effect. Chlorpromazine (0.5 mg/kg) caused a mixed inhibitory effect on the LPAH, whereas the AH was not affected, probably due to the variety of actions at different transmission systems. Clozapine (0.125 mg/kg) anatagonized the LSD effect indicating serotonolytic properties, whereas an additive influence on the AH might be caused by its cholinolytic properties. Sulpiride (10 mg/kg) potentiated both the AH and the LPAH, probably due to presynaptic dopaminergic mechanisms. Two conclusions can be drawn: (1) The results agree with and support the idea of a serotonergic modulation of the (predominant) mesolimbic dopaminergic system in the induction of locomotor effects. (2) The model of LPAH is useful to clearly differentiate typical from atypical neuroleptics, and to obtain information whether there is a primary involvement of dopaminergic or serotonergic mechanisms.
Improving mid-frequency contrast in sparse aperture optical imaging systems based upon the Golay-9 array

Sparse aperture imaging systems are capable of producing high resolution images while maintaining an overall light collection area that is small compared to a fully filled aperture yielding the same resolution. This is advantageous for applications where size, volume, weight and/or cost are important considerations. However, conventional sparse aperture systems pay the penalty of reduced contrast at midband spatial frequencies. This paper will focus on increasing the midband contrast of sparse aperture imaging systems based on the Golay-9 array. This is one of a family of two-dimensional arrays we have previously examined due to their compact, non-redundant autocorrelations. The modulation transfer function, or normalized autocorrelation, provides a quantitative measure of both the resolution and contrast of an optical imaging system and, along with an average relative midband contrast metric, will be used to compare perturbations to the standard Golay-9 array. Numerical calculations have been performed to investigate the behavior of a Golay-9 array into which autocorrelation redundancy has been introduced and our results have been experimentally verified. In particular we have demonstrated that by proper choice of sub-aperture diameters the average relative midband contrast can be improved by over 55%.
A thermodynamic description and phase relationships of the FeCr system: Part I the BCC phase and the sigma phase

Abstract A generalized approach which was applied successfully to account for the magnetic contribution to the thermodynamic properties of FeNi is applied to FeCr. The predicted magnetic specific heats for two bcc alloys at x Cr = 0.16 and 0.21 are in good agreement with the experimental data available in the literature. The magnetic Gihbs energy, enthalpy and entropy for the bcc phase are obtained accordingly. The nonmagnetic thermodynamic properties of the bcc phase are obtained primarily from thermochemical data as well as those for the sigma phase. The calculated stable and metastable equilibria involving the bcc and sigma phases are in reasonable agreement with data reported in the literature. The calculated metastable miscibility gap of the bcc phase is highly asymmetric and the calculated spinodals show unusual features.
Prenatal stress exposure alters postnatal behavioral expression under conditions of novelty challenge in rhesus monkey infants

This prospective study investigated whether mild maternal stress during pregnancy could alter the behavioral and affective responses in rhesus monkey infants in a complex, novel environment. Twenty-four rhesus monkey infants were tested on three occasions at 6 months of age in a novel environment. Twelve infants were derived from mothers exposed to a daily 10-min mild stressor from Day 90 to Day 145 postconception, while 12 were derived from mothers undisturbed during pregnancy. Prenatally stressed infants demonstrated more disturbance behavior, and lower levels of gross motor/exploratory behavior. Moreover, half of the prenatally stressed infants showed an abnormal response, falling asleep, while none of the control infants displayed this behavior. Males exhibited more clinging to surrogates, while females spent more time in gross motor/exploratory behaviors, with prenatally stressed males tending to spend the least time in gross motor/exploratory activity.
Orodental manifestations of facial port-wine stains

Background Patients with facial port-wine stains (PWS) often demonstrate oral manifestations of their disorder; however, the spectrum and prevalence of such findings among a cohort of patients with PWS has not been established. As a result, dermatologists and oral health specialists may be uncertain how to counsel their patients with PWS regarding oral hypervascularity, bony oral changes, and oral hygiene. Objectives We sought to identify physical findings and complications involving the teeth, oral cavity, and perioral structures in individuals with facial PWS. Methods This was a cross-sectional study of 30 patients with facial PWS. Descriptive data were collected through anonymous paired surveys completed by patients and their dentists, and analyzed (Fisher exact test) for trends based on physical findings and stage of the PWS. Results The most common orodental manifestations according to patients were enlargement of the lip (53.3%), stained gums (46.7%), abnormal bite (30%), and spontaneous bleeding of the gums (26.7%). Staining of the gingiva correlated significantly with gingival hyperplasia ( P = .006), maxillary hyperplasia ( P = .014), and widened interdental spaces ( P = .002), and in all cases gingival staining predated these findings. Lip hyperplasia was reported more frequently by patients than by their dentists (50% vs 18.2%, P = .008). Orodental manifestations were more common among patients with darker and thicker PWS. Hemorrhage after dental procedures was rare (4.5%). Limitations Modest sample size and difficulty recruiting control subjects are limitations. Conclusions Facial PWS commonly affect the orodental structures, and intraoral staining may predict future complications.
Electrical conductivity and rheology of carbon fiber/liquid crystal polymer composites

One emerging market for electrically conductive resins is for bipolar plates for use in fuel cells. Adding carbon fillers to thermoplastic resins increases composite electrical conductivity and viscosity. Current technology often adds as much of a single type of carbon filler as possible to achieve the desired conductivity, while still allowing the material to be extruded and molded into a bipolar plate. In this study, varying amounts of two different types of polyacrylonitrile (PAN) based carbon fiber (Fortafil 243 and Panex 30) were added to Vectra A950RX liquid crystal polymer. The resulting single fiber composites were then tested for electrical conductivity and rheological properties. The electrical conductivity followed the behavior typically seen in composites with a percolation threshold at 5 vol% for Fortafil 243 and at 13 vol% for Panex 30. Viscosity increased with increasing filler volume fraction for all shear rates, but was more rapid for the Fortafil 243 composites. Over the range of shear rates studied, the viscosity followed a shear-thinning power law model with power-law exponent (n – 1) = –0.5 for neat Vectra A950RX. Panex 30 had no effect on the power-law exponent and Fortafil 243 changed (n – 1) to −0.6. POLYM. COMPOS., 28:168–174, 2007. © 2007 Society of Plastics Engineers
The Life Change Inventory: A Device for Quantifying Psychological Magnitude of Changes Experienced by College Students:

Theoretical rationale, construction, and preliminary data on psychometric properties of the Life Change Inventory are presented. It provides a convenient device for investigating psychological consequences of different degrees of readjustment in college student's lives. Initial reliability data (test-retest = .68 and .88; Cronbach Alpha = .87), and personality and mood correlates (significant positive correlations with Profile of Mood States tension, depression, anger, and vigor, and with Differential Personality Inventory insomnia, headache proneness, feelings of unreality, hypochondriasis, ideas of persecution, impulsivity, perceptual distortion, and somatic complaints), are promising. Except for Profile of Mood States vigor, these significant correlations are consistent with the idea that excessive life changes have adverse psychological consequences.
The β-effect of silicon in the orthogonal geometry

Abstract The inductive contribution to the β-effect of silicon has been investigated through the preparation of 1-(trimethylsilyl)bicyclo[2.2.2]octan-2-ol (5-OH) and its sulfonate derivatives. The dihedral relationship in 5 between the trimethylsilyl group and the bond to the leaving group approaches orthogonality, preventing any contribution to the β-effect from either hyperconjugation or bridging. Any residual effect of silicon should come from induction. The rate of the tosylate, compared with that of the silicon-free model bicyclo[2.2.2]oct-2-yl tosylate (7-OTs), was found to be 1.2–1.3 in 80–97% aqueous trifluoroethanol at 20–35°C. This negligible β-effect compares with values of about 10 5 at the synperiplanar geometry, 10 4 at clinal geometries, and 10 12 at the antiperiplanar geometry. The complete dihedral dependence resembles the cosine-squared curve expected for a hyperconjugative mechanism rather than for bridging, with little contribution from induction.
The formation of carbamazepine epoxide by rat liver microsomes: an investigation of the biphasic kinetic profile

Abstract A biphasic profile has been found for the rat hepatic microsomal formation of carbamazepine 10, 11 -epoxide from varying concentrations of carbamazepine (CBZ). The two optima for epoxide formation appeared at substrate concentrations of about 0.3 mM and 1.0 mM CBZ, respectively, with a nadir occuring at 0.4 – 0.6 mM CBZ. The biphasic nature of the velocity-substrate profile was not due to metabolism or disappearance of the epoxide. Pretreatment of rats with phenobarbital or CBZ produced an increase in the epoxide formation at both low and high CBZ concentrations, whereas phenytoin (DPH) pretreatment increased epoxide only at low CBZ concentrations. 3-Methylcholanthrene treatment did not increase epoxide formation at either low or high CBZ concentrations. High and low affinity processes for epoxide formation developed in parallel in young rats. DPH added in vitro inhibited only the epoxide formation at high CBZ concentrations. This inhibitory effect increased with age of the rats. These findings indicate that CBZ 10, 11 -epoxide formation in rat liver microsomes proceeds by two metabolic pathways distinguished by substrate affinity and inhibition. Analysis of data from previous clinical studies reveals a biphasic pattern for plasma levels of CBZ, and its 10, 11 -epoxide.
The Mohr–Coulomb criterion from unit shear processes in metallic glass

Abstract The experimental and simulation-based evidence for asymmetric plastic yielding of metallic glasses is reviewed, and discussed within the framework of the Mohr–Coulomb criterion. The weight of evidence is supportive of normal stress-dependent yielding, although it is difficult to ascribe the origin of this effect to a particular mechanism given the myriad of complex physical processes that occur during plastic flow of metallic glasses. Using simple unit models of four- or nine-atom ‘shear transformation zones’, we show that Mohr–Coulomb yielding arises even at this very fine scale. Furthermore, by considering the topological difference between the four- and nine-atom models, we illustrate why the degree of the yield asymmetry in metallic glasses can vary over an appreciable range. We also discuss a potential breakdown of the Mohr–Coulomb criterion for states of high tensile stress in light of these unit models.
On some generalizations of the second grade fluid model

In this article, we provide a brief review of some generalizations of the second grade fluid model. We discuss certain similarities between these fluids and fluids of higher grades, while also describing certain limitations of these models. The new models that we put forth are based upon some interesting experimental results which suggest that not only can normal stress coefficients depend upon the shear rate, but that this dependency is in fact not the same rate as that of shear viscosity variation with shear rate. We then discuss some steady flows of these generalized second grade fluid models.
Miniaturized fiber raster scanner for endoscopy

ABSTRACT A miniaturized scanning mechanism is a crucial component in the creation of endoscopes for microscopic imaging. Several groups have developed resonant sca nners (e.g., spiral or Lissajous scan pa ttern), but these suffer from limitations in non-uniform spatial coverage and sampling time, in comparison to a raster scanner. Additionally, a resonant scanner lacks the ability to perform line-scan imaging, a crucial capability in measuring a variety of fast, dynamic physiological phenomena (e.g., blood flow, molecular diffusion, etc.). However, current miniaturized raster scanners are limited in terms of their physical dimensions and scan speed. We demonstrate a novel hybrid resonant/non-resonant miniaturized raster scanner, fabricated by mounting a double clad fiber onto two perpendicularly oriented piezo bimorphs. The fiber scanner has a total length of 2.6cm, a width/thickness  1mm, achieves  800 m fiber tip deflection for both the resonant and non-resonant axes, and allows for imaging at approximately 4 frames per second (512 lines per frame). An essentially uniform spatial coverage and sampling time can be achieved by utilizing the middle portion (e.g., middle 500 m) of the resonant scanning range. The small size allows for the fiber scanner to be easily packaged along with miniaturized lenses to form an endosc ope for microscopic imaging. We bonded a stiffening fiber alongside the vibrating fiber to break its cylindrical symmetry. Thus, only one vibration mode is excited, generating a purely linear spatial motion. In order to demonstrate the fiber scanners imaging capabilities we have taken transmission and fluorescence images, in which the double clad fibers inne r clad is used for fl uorescence collection. Keywords: fiber scanner, multiphoton endoscope, double clad fiber, raster scanner
Deflagration-detonation transition in hydrogen-air-steam mixtures — Relevance of the experimental results for real accident situations

Abstract After ignition of an explodable gas—air-mixture the combustion process, which starts as a deflagration, may turn into a much more destructive detonation if sufficiently high hydrogen concentration and suitable geometry are given. Geometric conditions for a deflagration-to-detonation transition (DDT) must be appropriate for flame acceleration and for the establishment of the DDT process itself by the SWACER mechanism. The objective of the experiments, performed from 1987 until 1988 at Battelle, was to determine, in quantitative terms, the detonation sensitivity under the influence of steam and to compare the DDT-limits thus determined with detonation limits measured elsewhere by direct initiation. A total of 30 experiments were carried out under this programme. The results of the experimental series are, that the following criterion needs to be fulfilled to achieve a DDT: — DDT is possible if the smallest compartment width is larger than or equal to the detonation cell width which allows a stable detonation to propagate in a given mixture. This criterion permits to apply the detonation cell width as a correlation between mixture properties and geometric dimensions also to DDT.
A multivariable prognostic model for equine colic patients

A survey of 1965 equine colic cases was conducted from August 1985 to July 1986 ten equine referral hospitals located througout the U.S.A. Two-thirds of the cases were randomly selected for model development (1336), while the remaining cases (629) were used only for subsequent validation of the model. The following outcomes were defined: (1) died or killed prior to discharge from the hospital; or (2) alive at the time of discharge. Only variables which were significant (P<0.05) in an initial bivariate screening procedure and for which there were less than 400 missing values were considered in the multivariable modelling. A multivariable logistic regression model was constructed using a stepwise algorithm. The model used 666 cases and included the following variables: peripheral pulse (normal or weak), pulse rate, surgical or medical treatment, packed cell volume, self-inflicted trauma (absent or present) and capillary refill time. For each horse in the validation data set which had the appropriate variables recorded (n=335), the estimated expected probability of death (expected value) was calculated using the logistic regression equation. Using Bayes theorem, the post-test probability was calculated from the expected value (an estimate of the test odds) and the present probability (the case-fatality rate at each institution). Nomograms of predictive values for different case-fatality rates and expected values were constructed. Hosmer-Lemeshow goodness-of-fit statistics indicated that the model fitted the model data set well but the validation set poorly. However, when the observed case-fatality rates were compared with the average post-test probabilities for 0.10 increments of post-test probability, qualitatively, the model's performance was better.
Mechanism of D-amphetamine inhibition of protein synthesis.

Abstract At 1 h after intraperitoneal administration of D -amphetamine sulphate (15 mg/kg), rat brain polyribosomes show disaggregation accompanied by reduced capacity for in vitro peptide chain elongation. The direct action of amphetamine on cell-free protein-synthesizing systems was therefore explored. When brain or liver polyribosomes from untreated rats were incubated with pH 5 enzyme peptide chain elongation was not inhibited by the addition of 4 mM amphetamine to the medium. On the other hand, an initiation-dependent system consisting of rat liver or brain mRNA and wheat germ S-30 fraction showed inhibition of [3H]leucine incorporation by 50% when 4 mM amphetamine were added. The metabolites of amphetamine, p-hydroxyamphetamine and p-hydroxynorephedrine, had no inhibitory action in either system, but the potent neurotoxin p-chloroamphetamine was a more powerful inhibitor of initiation than amphetamine. By using [3H]amphetamine, it was shown that amphetamine binds to the 80-S ribosomes of the wheat germ system. This binding depended on the presence in the system of natural liver or brain mRNA or several synthetic mRNAs, but was not promoted by polyuridylic acid as the messenger. Significantly, polyuridylic acid-dependent polyphenylalanine synthesis by the wheat germ system was not inhibited by amphetamine or p-chloroamphetamine. Therefore, it was concluded that amphetamine inhibits protein synthesis by interfering with initiation through a step related to formation of the mRNA ribosome complex.
The Windsor Ceramic Tradition in Southern New England

Irving Rouse and Carlyle Smith originally reconstructed the sequences of the Windsor tradition in their studies of Connecticut and New York pottery assemblages. Since that time additional local ceramic assemblages have been described in the literature. There have been few attempts to test the validity of the Rouse/Smith sequence with this information, however. Utilizing these data and unpublished research from southern Connecticut, this article demonstrates that the Rouse/Smith construct remains a valid concept in Connecticut archaeology. The new data fit into the traditional system, elaborating and expanding the typology and sequences. The continuation of certain types and attribute classes from one stage into the next supports Rouse's and Smith's contention of great time depth for the Windsor tradition. It also suggests we should rethink our models of cultural history and cultural change.
Activity of alkylated prolactin and human growth hormone in receptor and cell assays.

Abstract The disulfide bonds of two lactogenic hormones, ovine prolactin (oPRL) and human growth hormone (hGH), were reduced with dithiothreitol under denaturing conditions and alkylated with iodoacetic acid. The modified hormones were assayed for their ability to bind the plasma membrane-bound receptor for lactogenic hormone found in the rabbit mammary gland. S-Carboxymethylated ovine prolactin (SCM-oPRL) with all six cysteine residues modified had a nearly 300-fold decrease in binding as compared to native oPRL in a competitive binding assay using [125I]ovine prolactin. The S-carboxymethylated human growth hormone (SCM-hGH) had all four of its cysteine residues modified. It showed only a slightly reduced ability to bind the rabbit mammary gland prolactin receptor in a competitive binding assay with [125I]ovine prolactin. The two modified hormones were assayed for their ability to stimulate proliferation of the lactogen-dependent Nb 2 lymphoma cell line. SCM-oPRL required concentrations greater than 1 × 105 that of native oPRL to stimulate 50% of the maximum cell growth. SCM-hGH retained a significant amount of its ability to stimulate the Nb 2 lymphoma cells.
Utilization of milk proteins as starting materials for other foodstuffs.

The modern food-processing industry is placing more and more emphasis upon the utilization of protein ingredients to provide specific functional properties to a wide range of formulated foods. Isolated milk protein products represent an important and valuable source of protein ingredients due to their recognized superior nutritional, organoleptic and functional properties. This paper provides up-to-date information on the quantities, production processes, composition, general properties, and specific functional properties of the major milk protein products, e.g. caseinates, co-precipitates, lactalbumin, whey protein concentrates and milk blends. The subject of chemical and enzymic modification to improve certain functional properties of milk proteins is considered briefly.
Experiencing and Witnessing Familial Aggression and their Relationship to Physically Aggressive Behaviors among Filipino Adolescents

The effects of family violence on children's aggressive behaviors have been the focus of much research. However, results have been equivocal in at least the following three areas: (a) the specific effects on aggression of child-directed violence versus child-witnessed violence, (b) the salience of family violence as an explanation of aggression when other theoretically relevant explanations of aggression are controlled (i.e., peers, attachments, or moral beliefs), and (c) the gender-specific effects of family violence. Using a probability sample of adolescents from a medium-sized city in the Philippines, this article assesses the effects of child-directed and child-witnessed violence between parents on aggressive behaviors of adolescents while controlling for theoretically relevant explanations of aggression. Results show that child-witnessed and child-directed violence are positively and significantly related to self-reported aggression, that child-witnessed violence accounts for most of the variance in adolescent aggression, and that neither measures of family violence interacts with gender.
Hong Kong's financial industries in transition: An external perspective

Abstract As a consultant to hundreds of business in Hong Kong, Gaeta analyzes the development of Hong Kong with a consultant's eye. He traces the path Hong Kong has followed to become a global banking and financial-services center in the 1990s; discusses the current obstacles it has to face as this center rapidly matures—for example, in its move from laissez-faire to international regulatory standards- and discusses the future competitive and managerial challenges the country will face with China at the helm, such as skills and human resource development, goal setting and performance management.
Teaching residents to be teachers

In this Training Matters article, Samuel Frank advocates teaching as a ubiquitous skill that neurology residents need to acquire regardless of whether they are pursuing a career in clinical practice or academics. The author also discusses potential methods to assess and improve resident teaching skills.
The Relationship of Music to the Melody of Speech and to Syntactic Processing Disorders in Aphasia

Two new empirical studies address the relationship between music and language. The first focuses on melody and uses research in phonetics to investigate the long-held notion that instrumental music reflects speech patterns in a composer's native language. The second focuses on syntax and addresses the relationship between musical and linguistic syntactic processing via the study of aphasia, an approach that has been explored very little. The results of these two studies add to a growing body of evidence linking music and language with regard to structural patterns and brain processing.
White-tailed deer vary offspring sex-ratio according to maternal condition and age

We tested two models of adaptive offspring sex-ratio that predict opposite optimal reproductive strategies for female white-tail deer (Odocoileus virginianus). Trivers and Willard's model predicts that does (females) in particularly good condition should produce sons, and Williams refined their model to make specific predictions about optimal offspring number/sex choices. Verme's model results in very different predictions because of very different assumptions about which sex of offspring can best benefit from high levels of maternal resources. We found clear support for the Trivers and Willard/Williams model when we analyzed data from road-killed does, and we furthermore question several of the assumptions of the Verme model.
Attribution Style and Public Policy Attitudes Toward Gay Rights

Objective. This study examines the influence of beliefs about the cause of homo-sexuality on public policy attitudes concerning gay rights. Methods. Using data from the 1995 Oklahoma City Survey, we examine how beliefs about homosexuality as either a lifestyle choice or biological predisposition affect levels of support for gay rights. Results. Consistent with current debates over gay rights, our study reveals a strong positive association between biological attributions of homosexuality and support for gay rights. Opposition to gay rights is most pronounced among political conservatives, fundamentalist Protestants, persons with little or no favorable contact with gays, individuals who embrace negative stereotypes about gays, and persons with high scores on an index of homophobia. Conclusions. Etiological beliefs about homosexuality have a strong influence on public policy attitudes toward gay rights.
Endocrine Responses in Cows Milked by Hand and Machine

Plasma concentrations of oxytocin, prolactin, and cortisol were compared in five Swedish Red and White cows milked by hand versus machine. Cows were divided into two groups. One group was hand-milked; the other group was machine-milked. Treatments were switched every other day. The experiment was carried out for 6 d. Blood samples were taken prior to, during, and after milking and were assayed for hormones. More oxytocin and prolactin were released in hand-milked cows. There were no significant diurnal differences between the total amount of oxytocin released for the different treatments, but prolactin tended to be higher during hand-milking in the evening than in the morning milking. Cortisol concentrations were greater during hand-milking than during machine-milking. There were no significant treatment differences with regard to the total amount of cortisol released. During morning milking, cortisol concentrations were higher during hand-milking than during machine-milking. Our data show that hand-milking results in a pronounced and prolonged release of oxytocin and prolactin.