cssi/SciSciGPT-SciSciNet huggingface dataset:
Reordering constraints for pthread-style locks

C or C++ programs relying on the pthreads interface for concurrency are required to use a specified set of functions to avoid data races, and to ensure memory visibility across threads. Although the detailed rules are not completely, it is not hard to refine them to a simple set of clear and uncontroversial rules for at least a subset of the C language that excludes structures (and hence bit-fields).We precisely address the question of how locks in this subset must be implemented, and particularly when other memory operations can be reordered with respect to locks. This impacts the memory fences required in lock implementations, and hence has significant performance impact. Along the way, we show that a significant class of common compiler transformations are actually safe in the presence of pthreads, something which appears to have received minimal attention in the past.We show that, surprisingly to us, the reordering constraints are not symmetric for the lock and unlock operations. In particular, it is not always safe to move memory operations into a locked region by delaying them past a pthread_mutex_lock() call, but it is safe to move them into such a region by advancing them to before a pthread_mutex_unlock() call. We believe that this was not previously recognized, and there is evidence that it is under-appreciated among implementors of thread libraries.Although our precise arguments are expressed in terms of statement reordering within a small subset language, we believe that our results capture the situation for a full C/C++ implementation. We also argue that our results are insensitive to the details of our literal (and reasonable, though possibly unintended) interpretation of the pthread standard. We believe that they accurately reflect hardware memory ordering constraints in addition to compiler constraints. And they appear to have implications beyond pthread environments.
MRI evaluation of AIDS-related encephalopathy: Toxoplasmosis vs. lymphoma

The spectrum of cranial MRI findings was evaluated in 113 patients with the acquired immunodeficiency syndrome, assessing lesion number, size, location, and configuration in association with the autopsy and/or biopsy results. Correlation of cranial MRI and CT was performed in 32 patients. MRI was shown to be superior in sensitivity of lesion detection demonstrating more lesions than CT in 14 studies (44%) and equivalent information in 18 studies (56%). In no case did CT demonstrate lesions not detected on MRI. We conclude that MRI should be the study of choice in evaluating AIDS-related encephalopathy. Multiple lesions that involve both deep gray matter and white matter suggest the possibility of CNS lymphoma. The "target" appearance on MRI is not helpful in distinguishing toxoplasmosis from lymphoma.
Agmatine, the bacterial amine, is widely distributed in mammalian tissues

Abstract We sought to determine whether agmatine (decarboxylated arginine), a bacterial product recently discovered for the first time in mammalian brain, was contained in other organs. A method was developed for isolation of agmatine from tissue and detection by RP-HPLC following solid-liquid extraction and derivatization with o -phthalaldehyde and mercaptoethanol. Recovery was about 80% and the limit of fluorometric detection was about 10 pg on column. In male Sprague-Dawley rats agmatine was unevenly and widely distributed in many tissues confirming its presence in mammals. The highest concentration (~71 ng/mg wet weight) was found in stomach, with aorta and small intestine next, followed by smaller levels in spleen, adrenal, aorta, and skeletal muscle and brain. Serum concentrations were high. Agmatine in male Long Evans rats of 3, 12, and 24 months of age demonstrated similar but not identical tissue distribution without any effect of aging. Since agmatine binds to α 2 -adrenergic and imidazoline receptors, is bioactive in a number of tissues, is contained in neurons and is found in serum and tissues, the findings are consistent with a potential role for agmatine as a neurotransmitter and/or hormone. It also raises the possibility that agmatine may, as in bacteria, serve as a polyamine precursor along metabolic pathways previously not detected in mammals.
Analysis and Prediction of the Thermal Performance of Piezoelectrically Actuated Fans

An experimentally validated numerical model is developed to analyze the operation of a piezoelectrically actuated cantilever vibrating close to a heated surface. The vibrating cantilever acts as a fan and provides localized cooling. The numerical results for the flow field and heat transfer show satisfactory agreement with experiments. The numerical model is used to develop fan curves for the piezoelectric fans, using a methodology similar to that used in constructing pump or fan curves for conventional fans. A simplified model based on stagnation region heat transfer in impingement flows is also proposed to estimate the heat transfer from a piezoelectric fan. The velocities obtained from the piezoelectric fan curves generated are used in this impingement heat transfer model, and the predictions are found to agree with measured stagnation zone Nusselt numbers with an average deviation of 17%.
Risk factors for third molar extraction difficulty.

Purpose The purpose of this study was to measure the difficulty of third molar (M3) extractions and to identify demographic, anatomic, and operative variables associated with extraction difficulty. Materials and methods To address the research purpose, we implemented a prospective cohort study and enrolled a sample composed of patients presenting for M3 removal. Predictor variables were categorized as demographic, anatomic, and operative. The primary outcome variable was difficulty of extraction, measured as extraction time per tooth. The secondary outcome variable was the surgeon’s postoperative estimate of M3 extraction difficulty, measured on a 100-mm visual analog scale (VAS). Appropriate univariate, bivariate, and multivariate statistics were computed. Results The sample was composed of 82 subjects, having 250 M3s (53.2% mandibular) extracted, with a mean age of 26.2 ± 10.7 years; 57.3% were female, 72.0% were white. The mean operating time per M3 extraction was 6.9 ± 7.6 minutes. The mean estimate of difficulty was 39.6 ± 24.7 mm and was significantly correlated ( r = 0.68) with extraction time ( P P ≤ .05) with extraction time in a multivariate model. Conclusion Our model indicates that the difficulty of M3 extractions is governed primarily by anatomic and operative factors with minimal influence from demographic factors.
Interleukin-1 and tumor necrosis factor-mediated regulation of C3 gene expression in human astroglioma cells

In this report, we show that in the human astroglioma cell line D54-MG, both interleukin-1 (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) enhance C3 gene expression in a time- and dose-dependent manner. Kinetic analysis demonstrates that after 96 h, C3 mRNA levels increase approximately 30-fold and 20-fold in response to IL-1 beta or TNF-alpha, respectively. C3 protein production increases proportionally, reaching levels 36-fold and 18-fold higher than untreated controls upon exposure to IL-1 beta or TNF-alpha, respectively. D54-MG cells require a minimal 1 h exposure to IL-1 beta in order to enhance C3 gene expression significantly, while 4 to 8 h are required for TNF-alpha. Simultaneous treatment of D54-MG cells with IL-1 beta and interferon-gamma (IFN-gamma) resulted in an additive increase in both C3 mRNA and protein expression, a finding not seen with the combination of TNF-alpha and IFN-gamma. Primary rat astrocytes also express increased C3 mRNA levels after 48 h in response to IL-1 beta (5.3-fold increase) and TNF-alpha (7-fold increase), while an additive effect was observed upon simultaneous treatment with both IL-1 beta and IFN-gamma. In the central nervous system (CNS), endogenous complement and cytokine production by astrocytes, and enhancement by IFN-gamma, a product of activated T cells often seen in the CNS in neural autoimmune disease, may contribute to the pathogenesis of inflammatory demyelinating diseases such as multiple sclerosis.
Evaluation of fiber surfaces treatment and sizing on the shear and transverse tensile strengths of carbon fiber-reinforced thermoset and thermoplastic matrix composites

The mechanical performance of advanced composite materials depends to a large extent on the adhesion between the fiber and matrix. This is especially true for maximizing the strength of unidirectional composites in off-axis directions. The materials of interest in this study were PAN-based carbon fibers (XA and A4) used in combination with a thermoset (EPON 828 epoxy) and a thermoplastic (liquid crystal poymer) matrix. The effect of surface treatment and sizing were evaluated by measuring the short-beam shear (SBS) and transverse flexural (TF) tensile strengths of unidirectional composites. Results indicated that fiber surface treatment improves the shear and trasverse tensile strengths for both thermosetting and thermoplastic matrix/carbon fiber-reinforced unidirectional composites. A small additional improvement in strengths was observed as the result of sizing treated fibers for the epoxy composites. Scanning electron microscope photomicrographs were used to determine the location of composite failure, relative to the fiber-matrix interface. Finally, the epoxy composites SBS and TF strengths appear to be limited to the maximum transeverse tensile strength of the epoxy matrix, while the thermoplastic composite SBS and TF strengths are limited by the LCP matrix shear and transverse tensile strengths, respectively.
Law and Politics in Jacobean England: The Tracts of Lord Chancellor Ellesmere

Part I. Law and Politics: 1. The Making of a Legal Mind 2. Kingship and the Problem of Sovereignty 3. Lords and Commons 4. Reforming Privy Councillors: Crown Finances and the Administration of Government 5. The Problem of Law Reform 6. The Clash of Jurisdictions: Central and Local Authorities, Secular and Ecclesiastical 7. Les Enfants Terribles: Coke, Ellesmere, and the Supremacy of the Chancellor's Decree 8. The Provenance of Ellesmere's Tracts Part II. Ellesmere's Tracts: 9. 'A Coppie of a wrytten discourse by the Lord Chauncellor Elsemore concerning the Royall Prerogative' (c. 1604) 10. 'The Speech of the Lord Chancellor of England, in the Eschequer Chamber, touching the Post-Nati' (1608) 11. 'Special obseruacions touching all the sessions of the last parlement anno 7 Regis and etc.' (1611) 12. 'Thinges to be Considered of before a parlement to be Called' (1615) 13. 'Memorialles for Iudicature. Pro Bono Publico' (c. 1609) 14. 'Some Notes, and Remembrances, concerning Prohibitians, for Staying of suites in the Ecclesiastical Courts, and in the Courts of the Admiraltie' (1611) 15. 'The Lord Chancellor Egertons Observations upon ye Lord Cookes Reportes' (1615) 16. A breviate or direccion for the Kinges learned Councell collected by the Lord Chauncellor Ellesmere, mense septembris 1615 Anno Yacobi Regis'.
User experience: an umbrella topic

This position paper represents my views on how we address the multi-disciplinary needs of the user experience industry. While each profession struggles to deepen its core skills and membership offerings, it also needs to branch out beyond its traditional borders to serve its members' needs within a broader industry. "User experience" should be the topic that unites all of various professional organizations under an umbrella. Because each organization has its special contribution to the network (some at the core, some as specialists and others as interested parties), and each person will have different needs, a personalized portal should be built for the UX topic to help individuals cross over existing boundaries.
Beyond Walking With Video: Co-Creating Representation

This paper discusses a method I used to conduct a study of hygge, a Danish concept that is usually translated as “cosiness.” I wanted to learn more about hygge and how it related to technology in the home. The method I used builds on my experience with spatial ethnography, on Bruno Latour's theory of representation, and on the work of visual anthropologist Sarah Pink. I asked participants to use a video or still camera to help me document their home. With participant and researcher both behind the lens of a camera, I saw a significant remapping of the power relationship between researcher and participant; we were able to focus together on the material home as the object of the research. In addition to reducing the time needed to build rapport, this method offers a way to analyze cultural practices such as hygge that are not entirely visible in the material world.
Lack of dietary adaptation of intestinal 2‐monoglyceride acyl transferase

Acylation of 2-monopalmitin with (1-14C) palmityl-coenzyme A was studied with microsomal fractions isolated from the intestinal mucosa of both hamsters and rats. Microsomes from hamster intestinal mucosa yielded equal molar amounts of 1,2-diglycerides and triglycerides, while those from rats synthesized more 1,2-diglycerides (70%) than triglycerides (30%). Although the enzyme system from the hamster was almost twice as active (55 nmoles monoglyceride acylated/min/mg protein) as that from the rat (31 nmoles monoglyceride/acylated/min/mg protein), there was essentially no difference in the rates of acylation when animals were (A) fasted for 3 days, (B) fed a high fat diet (15% safflower oil), or (C) fed a high carbohydrate diet for 5 days.
Assessing Impact, DIF, and DFF in Accommodated Item Scores: A Comparison of Multilevel Measurement Model Parameterizations

This pedagogical article is intended to explain the similarities and differences between the parameterizations of two multilevel measurement model (MMM) frameworks. The conventional two-level MMM t...
Relationship among electrocardiographic potential amplitude, weight, and resistance/reactance/impedance in a patient with peripheral edema treated for congestive heart failure

Abstract We are presenting a 79-year-old woman with congestive heart failure (CHF) and marked peripheral edema, who responded to medical management by losing 19.7% of her weight. The patient was studied with daily weights, 12-lead electrocardiograms (ECGs), and body electrical resistance/reactance/impedance (R/R/I) measurements via electrodes applied on her hand and foot. In the process she showed a gradual increase in the QRS complexes in her daily ECGs pari passu with the weight loss, leading to a 27.4% increase in the sums of the QRS complexes from the 12 ECG leads (∑SQRS). In addition the patient revealed excellent correlations between weights and ∑SQRS (r = −.91, P = .013), weights and resistance (r = −.95, P = .004), reactance (r = −.86, P = .029), and impedance (r = −.95, P = .004). Other ECG sets including fewer leads were also employed and correlated with weights and the body electrical properties. It is concluded that loss of peripheral edema in patients with CHF is associated with augmentation of body R/R/I leading to augmented ECG QRS complexes. These findings link etiologically changes of ECG potentials to alteration of body electrical properties, and suggest that serial ECGs could be used in the monitoring of therapy of patients with CHF.
Mars Global Surveyor Thermal Emission Spectrometer (TES) observations of variations in atmospheric dust optical depth over cold surfaces

Abstract The Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument has returned over 200 million thermal infrared spectra of Mars taken between March 1999 and August 2004. This represents one of the most complete records of spatial and temporal changes of the martian atmosphere ever recorded by an orbiting spacecraft. Previous reports of the standard TES retrieval of aerosol optical depth have been limited to those observations taken over surfaces with temperatures above 210 K, limiting the spatiotemporal coverage of Polar Regions with TES. Here, we present an extension to the standard TES retrieval that better models the effects of cold surfaces below 200 K. This modification allows aerosol optical depth to be retrieved from TES spectra over a greater spatiotemporal range than was previously possible, specifically in Polar Regions. This new algorithm is applied to the Polar Regions to show the seasonal variability in dust and ice optical depth for the complete temporal range of the TES database (Mars Year 24, L s = 104 ° , 1 March 1999 to Mars Year 24, L s = 82 ° , 31 August 2004).
Structural performance assessment under near-source pulse-like ground motions using advanced ground motion intensity measures

This paper demonstrates the effectiveness of utilizing advanced ground motion intensity measures (IMs) to evaluate the seismic performance of a structure subject to near-source ground motions. Ordinary records are, in addition, utilized to demonstrate the robustness of the advanced IM with respect to record selection and scaling. To perform nonlinear dynamic analyses (NDAs), ground motions need to be selected; as a result, choosing records that are not representative of the site hazard can alter the seismic performance of structures. The median collapse capacity (in terms of IM), for example, can be systematically dictated by including a few aggressive or benign pulse-like records into the record set used for analyses. In this paper, the elastic-based IM such as the pseudo-spectral acceleration (Sa) or a vector of Sa and epsilon has been demonstrated to be deficient to assess the structural responses subject to pulse-like motions. Using advanced IMs can be, however, more accurate in terms of probabilistic response prediction. Scaling earthquake records using advanced IMs (e.g. inelastic spectral displacement, Sdi, and IM1I&2E; the latter is for the significant higher-mode contribution structures) subject to ordinary and/or pulse-like records is efficient, sufficient, and robust relative to record selection and scaling. As a result, detailed record selection is not necessary, and records with virtually any magnitude, distance, epsilon and pulse period can be selected for NDAs. Copyright © 2008 John Wiley & Sons, Ltd.
Oral health issues for adolescent athletes.

Standardized definitions of the adolescent period often fail to capture the complexities that live within the growing, developing, and maturing individual adolescent. The dynamics associated with the concurrent physical, hormonal, emotional, and social changes not only focus the former child toward maturity and acculturation into the social milieu of adulthood but may also contribute to antisocial actions and problem risk-taking behaviors. Perhaps one might suggest an alternative characterization of adolescence as a transitional period of living with contradictions. One focus of attention during this transitional period for many adolescents is an emphasis on the importance of sports. Adolescents should be encouraged to engage regularly in vigorous physical activities and to experience the exhilaration of competing in organized sports to the level of their individual capabilities. Adolescents not only benefit physiologically from the positive effects of sustained exercise but self-awareness, skill development, and a sense of accomplishment may also contribute psychologically to the overall health, self-esteem, and well-being of the individual adolescent athlete. Despite all of these healthful benefits associated with participating in sports, increased risks must be acknowledged. One essential goal for health professionals including the dental team is to focus on optimizing the benefitto-risk ratio for player safety and health. One critical aspect of this focus is to promote sports-specific preventive measures for the gamut of potential oral conditions, particularly sports-related traumatic dental injuries. Dental practices that provide such services to their patients are encouraged to
DIFFERENT (DIRECT and INDIRECT) MECHANISMS FOR THE INDUCTION OF DNA-PROTEIN CROSSLINKS IN HUMAN CELLS BY FAR- and NEAR-ULTRAVIOLET RADIATIONS (290 and 405 nm)

Abstract— Apparent DNA-protein crosslinking induced by monochromatic 290 and 405 nm Tadiations was measured in cultured human P3 teratocarcinoma cells with DNA alkaline elution techniques. The rates of the induction of crosslinks by 290 nm radiation were the same when the cells were irradiated either aerobically or anaerobically or when the cells were in an H2O or D2O aqueous environment. With 405 nm radiation, anaerobic irradiation reduced the induction of the crosslinks (dose modifying factor is about 0.2), and about twice as many crosslinks were observed when the cells were irradiated in an environment of D2O rather than H2O. The results are consistent with the hypothesis that far-UV radiation induces DNA-protein crosslinks by a direct mechanism, whereas near-UV radiation induces crosslinks via indirect photodynamic photosensitizations in which unidentified cellular endogenous photosensitizers and reactive species of oxygen are used.
A new device to help facilitate manual spermatophore transfer in penaeid shrimp.

Abstract A continuous gill irrigator has been developed, in combination with a restraining device, to keep female penaeid shrimp alive and to reduce stress during manual spermatophore transfer (a form of artificial insemination). Construction, cost, and use of the equipment are described.
Differential phosphorylation of band 3 and glycophorin in intact and extracted erythrocyte membranes

This report presents an analysis of the phosphorylation of human and rabbit erythrocyte membrane proteins which migrate in NaDodSO4-polyacrylamide gels in the area of the Coomassie Blue-stained proteins generally known as band 3. The phosphorylation of these proteins is of interest as band 3 has been implicated in transport processes. This study shows that there are at least three distinct phosphoproteins associated with the band 3 region of human erythrocyte membranes. These are band 2.9, the major band 3, and PAS-1. The phosphorylation of these proteins is differentially catalyzed by solubilized membrane and cytoplasmic cyclic AMP-dependent and -independent erythrocyte protein kinases. Band 2.9 is present and phosphorylated in unfractionated human and rabbit erythrocyte ghosts but not in NaI- or dimethylmaleic anhydride (DMMA)-extracted membranes. These latter membrane preparations are enriched in band 3 and in sialoglycoproteins. The NaI-extracted ghosts contain residual protein kinase activity which can catalyze the autophosphorylation of band 3 whereas the DMMA-extracted ghosts are usually devoid of any kinase activity. However, both NaI- and DMMA-extracted ghosts, as well as Triton X-100 extracts of the DMMA-extracted ghosts, can be phosphorylated by various erythrocyte protein kinases. The kinases which preferentially phosphorylate the major band 3 protein are inactive towards PAS-1 while the kinases active towards PAS-1 are less active towards band 3. The band 3 protein in the DMMA-extracted ghosts can be cross-linked with the Cu2+ -σ-phenanthroline complex. The cross-linking of band 3 does not affect its capacity to serve as a phosphoryl acceptor nor does phosphorylation affect the capacity of band 3 to form cross-links. In addition to band 2.9, the major band 3 and PAS-1, another minor protein component appears to be present in the band 3 region in human erythrocyte membranes. This protein is specifically phosphorylated by the cyclic AMP-dependent protein kinases isolated from the cytoplasm of rabbit erythrocytes. The rabbit erythrocyte membranes lack PAS-1 and the cyclic AMP-dependent protein kinase substrate.
Marginal Cost Pricing of Recursive Lumpy Investments

Problems involving optimal decentralization of decision-making in the presence of nonconvexities have a long, frustrating history. Solutions generally involve evaluation of a surplus term and economists have been unable to discover ways of revealing that term without the collection of hypothetical information. However, certain non-convex problems have additional structure which can be exploited in order partially to circumvent this difficulty. We will focus here on such a problem involving capacity construction. Suppose that we restrict attention to problems involving a single type of capacity (for example, electric power, telephone channels, highway through-put, bridges or dams), and for which the non-convexities are involved in the construction of capacity but not in the production of services from capacity. This class of problems seems fairly broad in scope and has a long history generally associated with the French economists (see Nelson (1964) for a survey). We begin by summarizing the French approach as discussed by Boiteux (Chapter 3 in Nelson, op. cit.). Boiteux discusses the non-convex replacement problem, using railway cars as the paradigm. First, he attempts to apply marginal analysis to the problem of pricing capacity in this situation. Under the usual rules of marginal cost pricing, the price of a ticket should be zero as long as the last car is not full, but should jump up to the marginal cost per person handled of adding an additional car as soon as it is full. Now, if at the zero price demand exceeds the capacity of this car, while at the second it falls short, there is clearly no equilibrium outcome; marginal analysis fails to tell us what to do. Considered in isolation, we are left with the classical non-convexity dilemma: to decide whether or not the extra car is justified, we must compare the cost against the full consumer surplus generated. However, Boiteux notices that the problem should not be considered in isolation.
Preparation of a crotoxin neutralizing monoclonal antibody

Crotoxin is a heterodimeric protein composed of an acidic and basic subunit from the venom of Crotalus durissus terrificus and is representative of a number of presynaptically acting neurotoxins found in the venom of rattlesnakes. Four different monoclonal antibodies, typed as IgG1 subclass, were raised against the basic subunit of this toxin. One was a potent neutralizing antibody of intact crotoxin, which could neutralize approximately 1.6 moles of purified crotoxin per mole of antibody. The monoclonal antibody enhanced the neutralizing ability of commercial polyvalent crotalid antivenom against the lethality of crude C. d. terrificus venom four-fold. Paradoxically, this monoclonal antibody by itself was ineffective against the lethality of crude C. d. terrificus venom. Using an enzyme-linked immunosorbent assay, we tested various proteins for competitive inhibition of binding of biotinylated-crotoxin to plates coated with the four individual monoclonal antibodies. Concolor toxin, vegrandis toxin, intact crotoxin, Mojave toxin, and the basic subunit of crotoxin showed increasing effectiveness as displacers of crotoxin from the neutralizing monoclonal antibody. None of the monoclonal antibodies reacted with purified phospholipase A2 enzymes from Crotalus atrox or Crotalus adamanteus, nor any of the components present in the crude venoms from four different elapids known to contain presynaptically acting neurotoxins, which show some sequence identity to crotoxin.
When talking less is more: Exploring outcomes of Twitter usage in the large-lecture hall

This article employs a mixed‐method approach to examine the outcomes produced by using Twitter in a large‐lecture course as a means to assess the pedagogical impact and potential of Twitter’s contribution to large‐lecture course dynamics. In doing so, it seeks also to explore the broader relationship between methodologies and outcomes. Exploratory in nature and design, this study proceeds from the recognition of the inherent limitations and unpredictability in investigating how new technologies transform social patterns. Such an approach allows us to question how the mode and design of our research ultimately frame the interpretation and understanding of how social media intersect and impact classroom dynamics and their potential contributions for developing more effective pedagogical strategies and outcomes.
Analytical chemistry of chromium.

Abstract The determination of chromium in most biological materials is extremely difficult because of the very low levels present. Easily accessible samples, for example biological fluids such as serum, urine, etc., usually have chromium concentrations well below 1 ng g −1 . The only widely available analytical method with sufficient sensitivity is graphite furnace atomic absorption spectrometry (GFAAS), yet values reported in the early literature were wildly divergent. Man appeared to be excreting several times the amount of chromium he was absorbing from his diet. This dilemma was resolved in 1978 when it was shown that all previous chromium analytical results were probably wrong (too high), due to limitations of the instrumentation used up until then. Subsequent instruments with improved background correction capabilities have removed this limitation. However, making determinations at the sub-parts-per-billion level remains a formidable task in terms of contamination control.
Cerebellar Lingula Size and Experiential Risk Factors Associated with High Levels of Alcohol and Drug Use in Young Adults

Previous studies have reported cerebellar abnormalities or static ataxia associated with risk for chronic use of alcohol and drugs. Adverse childhood experience is another strong risk factor for later substance abuse. We therefore sought to ascertain the relationship between morphological phenotypes of the lingula (lobule I) of the anterior cerebellar vermis, and exposure to emotional (EM) versus physical (PM) maltreatment, on the degree of ongoing alcohol or drug use. The study design consisted of a cross-sectional in vivo neuroimaging study, utilizing retrospective assessment of maltreatment history and self-reports of alcohol and substance use. Study participants were 153 subjects (54 M/99F, 21.9 +/- 2.2 years) selected for imaging from a database of 1,402 community participants 18-25 years of age, who completed a detailed online screening instrument and met rigorous inclusion/exclusion criteria. Subjects were exposed to only physical abuse or harsh corporal punishment (HCP; PM group, n = 37) and parental verbal abuse and/or witnessing domestic violence (EM group, n = 58) or had no history of maltreatment or axis I disorders (n = 58). The main outcome measures consisted of the gray matter volume of lobule I as measured by manual tracing, number and type of alcoholic beverages consumed during a drinking session, number of sessions per month, and monthly drug use, along with family history of drug and alcohol abuse. Lingula thickness was not attenuated by alcohol use or maltreatment history. However, increased lingula thickness was associated with greater consumption of drugs and hard liquor, particularly in physically maltreated subjects who consumed 2.5- and 2.7-fold more alcohol and used drugs 6.1- and 7.8-fold more frequently than controls or EM subjects, respectively. In conclusion, physical maltreatment was observed to interact with cerebellar morphology resulting in a strong association with alcohol and substance use. Lingula thickness may represent a novel, experientially sensitive, phenotypic risk factor for enhanced alcohol and drug use that perhaps modulates sensitivity to these agents.
Beyond gap junctions: Connexin43 and bone cell signaling

Connexin43 (Cx43) is the most abundant gap junction protein expressed in bone cells and plays a central role in cell-to-cell communication in the skeleton. Findings of the last decade uncovered functions of Cx43 hemichannels expressed on unopposed plasma cell membranes as mediators of the communication between bone cells and their extracellular milieu. Additionally, through its cytoplasmic C-terminus domain, Cx43 serves as a scaffolding protein that associates with structural and signaling molecules leading to regulation of intracellular signaling, independent of channel activity. This perspective discusses the evidence demonstrating that via these diverse mechanisms Cx43 is a key component of the intracellular machinery responsible for signal transduction in bone in response to pharmacologic, hormonal and mechanical stimuli. This advance in the knowledge of the role of connexins increases our understanding of the pathophysiological mechanisms that regulate bone cell function and provides new opportunities to treat bone diseases.
EARLY-TYPE GALAXIES IN EXTREMELY ISOLATED ENVIRONMENTS: TYPICAL ELLIPTICALS?

We have conducted a BVR imaging survey of nine early-type galaxies previously verified to exist in extremely isolated environments. Our goals are to establish a baseline of morphological and photometric properties for spheroidal systems evolving in extremely low-density environments and to compare these properties with signatures predicted for merged galaxy groups. We find that these isolated systems are underluminous by at least a magnitude compared with objects identified as merged group remnants in other studies. Image processing techniques sensitive to shell features produced no detections, a result in strong contrast to the high frequency of such structures found in other isolated elliptical galaxies. Two objects, KIG 164 and KIG 870, appear to be merger remnants, as indicated by their disturbed morphology, apparent tidal features, and blue colors. KIG 164 exhibits an asymmetric nuclear morphology and a low surface brightness "bridge" between it and a possible dwarf satellite. KIG 870 shows both fan-shaped emission at large radii and a possible double nucleus. Two other galaxies, KIG 412 and KIG 792, are also blue, but without any morphological peculiarities, suggesting that these systems are advanced mergers, older than KIG 164 and KIG 870. Two systems appear to be isolated lenticular galaxies with no evidence of a merger history. Based on their red colors, good fit to a R1/4-law light distribution, and the lack of morphological peculiarities, two other galaxies, KIG 557 and KIG 824, are found to be excellent candidates for passively evolving primordial elliptical galaxies formed early in cosmic time. Optical data were obtained with the 2.1 m Otto Struve telescope at McDonald Observatory, which is operated by the University of Texas at Austin.
Expression of stem cell factor receptor (c-kit) by the malignant mast cells from spontaneous canine mast cell tumours.

Summary Stem cell factor receptor (SCFR, c- kit ), normally expressed on haematopoietic and mast cells, plays a regulatory role in cellular growth and differentiation. Dysregulated expression of SCFR may contribute to neoplastic transformation. We investigated expression of SCFR on malignant canine mast cells obtained directly from spontaneous canine mast cell neoplasms, in an attempt to determine whether these undifferentiated cells maintained expression of this growth-promoting cytokine receptor. Malignant mast cells (histological grade 2) from skin tumours or lymph node metastases were collected from canine patients, and SCFRs were detected by flow cytometric analysis of these cells. All of the tumours bound mouse and canine recombinant stem cell factor (SCF), indicating that the cells not only expressed SCFRs, but that the receptors possessed the functional property of ligand binding. Immunoglobulin Fc receptors for canine IgE were identified on these cells by flow cytometry, a further indication that the cells analysed were mast cells and retained some differentiated features. Immunohistochemical analysis of formalin-fixed, paraffin wax-embedded mast cell tumour biopsies confirmed expression of SCFRs by malignant cells from each tumour. The relative binding of SCF to suspensions of tumour cells, as assessed by flow cytometry, correlated with the intensity of immunolabelling for SCFR in sections of the same tumours, suggesting variability in SCFR expression between tumours. Agarose gel electrophoresis of the products of SCFR reverse transcription-polymerase chain reaction derived from each tumour had the molecular weight predicted for canine SCFR cDNA on the basis of the mouse and human counterparts. This further confirmed SCFR expression by malignant canine mast cells. Taken together, these results show that a membrane receptor capable of triggering cell growth is expressed by malignant canine mast cells, suggesting a role for this receptor in the aetiology of canine mast cell cancer. This relatively common malignancy of the dog would seem to present an opportunity for the investigation of the potential role of the SCF/SCFR pathway in the development of spontaneous malignancies of mast cells.
The politics of foreign debt in Latin America a study of the debtors’ cartel

This analysis of the foreign debt problem in Latin America shows that this economic burden is onerous and will not be reduced in the short run. The region's political leaders perceived that collective bargaining could increase their bargaining leverage with foreign lenders and could produce more advantageous repayment schedules for most nations. However, despite verbal backing and the economic promise of collective bargaining, a debtors’ cartel failed to materialize. Evaluations of the political dynamics in key nations anticipated creditors. This analysis also shows that the debtors’ cartel failed because collective bargaining did not gain domestic political support. Foreign influence was tangential to the outcome. Given this political climate, the chances for a revival of collective bargaining are very slim.
House Science Committee sets agenda

An informal briefing a few weeks ago by the House Science, Space, and Technology Committee staff provided a good overview of high-priority science issues that they will address. The committee plans to revisit some issues as well as consider new matters of interest. There is much uncertainty about the Clinton administration's budget request, with no firm information about Space Station Freedom or budgets for the National Science Foundation, Department of Energy, or NASA. The Office of Management and Budget is assembling the new budget, which will then be sent to the agencies for review. March 23 is the current target date for release of the detailed budget document.
High-spectral-resolution lidars for atmospheric measurements

Although LIDAR (light detection and ranging) technique has been used to probe the atmosphere before the invention of lasers, remote measurement of several important atmospheric parameters, which require high spectral resolution, is only recently being done. After a brief overview on lidar technique for atmospheric parameter measurements, I discuss the ongoing efforts for atmospheric probing using a high-spectral-resolution lidar system at Colorado State University.
Estimating probabilities of correct identification from results of mass spectral library searches

This work presents a method for using mass spectral match factors reported by library search systems to obtain certain probabilistic indicators of correct identification. The overall probability that a retrieval is correct is formally separated into two independent terms. One of these is the probability that a retrieval is correct assuming that the correct match is contained in the library. This can be computed directly from test results. The other term represents the probability that the spectrum of the unknown compound is actually in the library. While the absolute value of this term cannot be computed, a relative value based solely on search results can be derived. This value may, if desired, be used to refine an initial estimate of the overall probability. Parameters used in this calculation are based on changes in test results caused by the logical removal of the test compounds from the library. These methods were parameterized from results of searching the MST/EPA/NIH Mass Spectral Database with 12,592 good quality replicate spectra and a simple mass spectral comparison function. The methodology should be equal1 applicable to other libraries and search systems.
AN EVALUATION MODEL FOR MASTERY TESTING1

Noting the desirability of the current shift toward mastery testing and criterion-referenced test procedures, an evaluation model is presented which should be useful and practical for such purposes. This model is based on the assumptions that the learning of fundamental skills can be considered all or none, that each item response on a single skill test represents an unbiased sample of the examinee's true mastery status, that measurement error occurring on the test (as estimated from the average interitem correlation) can be of only one type (α or β) for each examinee, and that through practical and theoretical considerations of evaluation error costs and item error characteristics, an optimal mastery criterion can be calculated. Each of these assumptions is discussed and the resultant mastery criteria algorithm is described along with an example from the IPI math program.
A comparison of doubly curved crystals and polycapillary optics for monochromatic beam production from a clinical source

Monochromatic beams produced with synchrotron sources are known to give higher contrast for mammography than clinical broadband sources. Monochromatic beams could also be achieved with clinical x-ray sources, by diffraction off of flat monochromator crystals, but monochromatic intensities are too low for imaging because only a small fraction of the incident beam is at the right energy and angle. With the use of polycapillary optics, monochromatic intensities could be increased. Two different x-ray optics schemes were tested to provide high monochromatic intensity from conventional divergent sources. A polycapillary collimating optic was employed to collect a large solid angle and redirect it into a parallel beam, which can be efficiently diffracted from a flat crystal. Measurements were performed for crystals of varying angular acceptance because there is a trade-off between intensity and resolution. Alternatively, doubly curved crystal (DCC) optics can be used to collect and focus monochromatic x rays from a divergence source. Higher monochromatic intensity can be obtained because the DCC optic diffracts and focuses the incident beam across the whole area of the crystal. For both methods, monochromatization occurs before the patient, resulting in a potential dose reduction as well as significant measured contrast enhancement. Measurements were made of contrast, resolution and intensity for the two techniques, and were compared to each other and to theoretical calculations.
Threshold retinopathy of prematurity in neonates less than 25 weeks' estimated gestational age.

Abstract Introduction: The survival rate of extremely premature infants has increased. No recent study has investigated the characteristics of retinopathy of prematurity (ROP) or the incidence of threshold ROP in the most severely premature infants. We undertook this study to determine the risk of developing ROP and threshold ROP in the growing sub-population of infants Methods: A retrospective review of infants born before the 25th week of gestation between the years 1994 and 1997 was performed. Of 49 infants examined (97 eyes), 42 were born in the 24th week of gestation and 7 were born in the 23rd week. Mean follow-up was 6.3 months (range, 2.5–37 months). Ophthalmology screening examinations were initiated at 5 weeks of age and continued until the infants were no longer at risk for serious ROP. Results: ROP developed in all (97) eyes. Thirty-nine of 97 (40%) eyes in 20 of 49 (41%) infants developed threshold ROP, diagnosed at a mean post-conceptional age of 34 weeks. Thirteen (13%) eyes of 7 (14%) patients developed prethreshold disease and regressed without treatment. Conclusion: There is an increased incidence of threshold disease in infants ≤25 weeks' EGA compared with children of greater EGA. Threshold disease may occur at an earlier post-conceptional age in this subgroup of neonates. (J AAPOS 2000;4:183–5)
Daisies, Kayles, and the Sibert-Conway decomposition in misegre octal games

Sibert and Conway [to appear] have solved a long-standing open problem in combinatorial game theory by giving an efficient algorithm for the winning misere play of Kayles, an impartial two-player game of complete information first described over 75 years ago by Dudeney (1910) and Loyd (1914). Here, we extend the Sibert-Conway method to construct a similar winning strategy for the game of Daisies (octal code 4·7), and then more generally solve all misere play finite octal games with at most 3 code digits and period two nim sequence ∗1, ∗2, ∗1, ∗2, ….
Comparison between the Torquato-Rintoul bounds for the interface effect in composite media and elementary results

We show that the interface effect on the properties of composite media recently proposed by Torquato and Rintoul equally follows from taking the limit in the dipolar polarizability of a coated sphere: the critical values are simply those that make the dipolar polarizability vanish. We also show that the Torquato-Rintoul bounds are either close to the Clausius-Mossotti relation or provide poor estimates. Finally, we notice that their bounds do not agree particularly well with experimental data.
HOMOLYTIC BASE-PROMOTED AROMATIC ALKYLATIONS BY ALKYLMERCURY HALIDES

Electron transfer chain reactions leading to substitution in electronegatively substituted benzene derivatives can be observed with alkylmercury halides in the presence of proton acceptors such as ...
Thermal damage reduction associated with in vivo skin electroporation: A numerical investigation justifying aggressive pre-cooling

Abstract Electroporation is an approach used to enhance transdermal transport of large molecules in which the skin is exposed to a series of electric pulses. Electroporation temporarily destabilizes the structure of the outer skin layer, the stratum corneum, by creating microscopic pores through which agents, which ordinarily are unable to pass into the skin, are able to pass through this outer barrier. Of possible concern when exposing biological tissue to an electric field is thermal tissue damage associated with Joule heating. In order to find the electrical and transient thermal solutions associated with this process, this study develops a three-dimensional transient finite-volume composite model of in vivo skin electroporation. The electroporation process modeled consists of five 150 ms long DC square wave pulses administered at 1-s intervals with an applied voltage of 400 V. This paper finds that minor thermal influence of the electrode plate and the of a small presence blood vessel have a large impact on thermal damage. An aggressive pre-cooling technique is presented which is shown to dramatically reduce the risk of thermal damage.
Relationship between temperature and velocity profiles in a turbulent boundary layer along a supersonic nozzle with heat transfer

Turbulent boundary layer air flow through supersonic convergent-divergent nozzle with heat transfer, considering relationship between temperature and velocity profiles
The Determination of Weights for Use in Calculating Tristimulus Values

Multiplication of weights by spectral radiance factors and summation is the usual method of calculating tristimulus values. The spectral-radiance-factor data may vary in abridgement (omission of intermediate data), truncation (omission of data at the extremes of the visual range), and in the case of fluorescent-lamp illuminants, omission of mercury-line data. This article sets forth recommendations for the calculation of weights for any set of spectral-radiance-factor data.