cssi/SciSciGPT-SciSciNet huggingface dataset:
The M-Server Queue with Poisson Input and Gamma-Distributed Service of Order Two

Analysis is made of the multiserver-queuing systems with Poisson input and service times distributed according to a second order gamma distribution. A set of difference equations involving the time-invariant state-probabilities is derived and a unique solution of these equations is found. The method used is that of treating the gamma-distributed service times or order two as the sum of two independent and identically distributed service times, which are exponentially distributed. It is shown that the time invariant probability of n customers being in the system is of the form, Pn = âi=0i=mCiβin, where m is the number of servers, and a method for finding the Ci's and βi's is given.
Counterconditioning and extinction of fear fail to transfer from amobarbital to nondrug state

Three dosages of amobarbital sodium all aided albino rats to resume a previously punished lever-pressing response. This finding was obtained in a test of counterconditioning and extinction of fear-motivated avoidance, with 108 animals divided into groups which were given placebo or one of three dosages of amobarbital (10, 20, or 30 mg/kg). In a subsequent test for transfer of counterconditioning and extinction to the nondrug state, with placebo given to all the animals, the superior performance under the drug failed to transfer to the nondrug state. On the contrary, there was the suggestion of an inverse relationship between performance in the test for transfer to the nondrug state and drug dosage during the prior test for effect of amobarbital. This experiment demonstrates that the stimulus-change decrement produced by a shift from the drugged to the nondrug state may prevent the therapeutic retraining under the drug from transferring to the nondrug state.
Genetic and environmental contributions to alcohol dependence risk in a national twin sample: consistency of findings in women and men

Background. Genetic influences on alcoholism risk are well-documented in men, but uncertain in women. We tested for gender differences in genetic influences on, and risk-factors for, DSM-III-R alcohol dependence (AD).Method. Diagnostic follow-up interviews were conducted in 1992–3 by telephone with twins from an Australian twin panel first surveyed in 1980–82 (N=5889 respondents). Data were analysed using logistic regression models.Results. Significantly higher twin pair concordances were observed in MZ compared to DZ same-sex twin pairs in women and men, even when data were weighted to adjust for over-representation of well-educated respondents, and for selective attrition. AD risk was increased in younger birth cohorts, in Catholic males or women reporting no religious affiliation, in those reporting a history of conduct disorder or major depression and in those with high Neuroticism, Social Non-conformity, Toughmindedness, Novelty-Seeking or (in women only) Extraversion scores; and decreased in ‘Other Protestants’, weekly church attenders, and university-educated males. Controlling for these variables, however, did not remove the significant association with having an alcoholic MZ co-twin, implying that much of the genetic influence on AD risk remained unexplained. No significant gender difference in the genetic variance in AD was found (64% heritability, 95% confidence interval 32–73%).Conclusions. Genetic risk-factors play as important a role in determining AD risk in women as in men. With the exception of certain sociocultural variables such as religious affiliation, the same personality, sociodemographic and axis I correlates of alcoholism risk are observed in women and men.
HOW DO RATERS FROM INDIA PERFORM IN SCORING THE TOEFL IBT™ SPEAKING SECTION AND WHAT KIND OF TRAINING HELPS?

This study investigated the scoring of the Test of English as a Foreign Language™ Internet-based Test (TOEFL iBT™) Speaking section by bilingual or multilingual speakers of English and 1 or more Indian languages. We explored the extent to which raters from India, after being trained and certified, were able to score the Speaking section for TOEFL iBT examinees with mixed first language (L1) backgrounds, especially those speaking an Indian language, accurately and consistently. The effectiveness of a special training package designed for scoring Indian examinees was examined as well. A total of 26 trained and certified raters from India were randomly divided into 2 groups and participated in 2 on-site scoring sessions in Mumbai. In the first session, both groups received regular training for scoring the TOEFL iBT Speaking section, which was largely similar to that received by raters in North America. In the second scoring session, 1 group continued to receive the regular training while the second group was trained using a special training package. Rater feedback surveys were also given to the raters. It was found that with training similar to that which operational U.S.-based raters receive, the raters from India performed as well as the operational raters in scoring both Indian and non-Indian examinees. In addition, the special training helped the raters score Indian examinees more consistently, leading to increased score reliability estimates. It also boosted raters' levels of confidence in scoring Indian examinees.
Synthesis and characterization of a technetium nitrido dimer

Abstract In 1993, Baldas et al. [1] reported the synthesis of the technetium(VI) nitridodi (μ-oxo) dimer (AsPh4)2[{TcNCl2}2(μ-O)2], which was synthesized from methanesulfonic acid and Cs2[TcNCl5] in water with heating. We report here, the facile synthesis and characterization of the tetrabutylammonium analog, (Bu4N)2[{TcNCl2}2(μ-O)2] (1), which is synthesized from (Bu4N)[TcNCl4] and water in acetone at room temperature. This may have important ramifications for technetium based radiopharmaceutical development, since [99mTcNCl4]− is frequently employed at the tracer level as a technetium nitrido synthon, and technetium nitrido chemistry continues to be a rapidly developing area in radiopharmaceutical research [1] . The infrared spectrum of 1 displays a pronounced absorption at 1062 cm−1, attributed to the TcN bond. The FAB(−) mass spectrum displays the parent ion of 642 m/z which corresponds to {(Bu4N)[{TcNCl2}2(μ-O)2]}−. The X-ray crystal structure of 1 is similar to the previously reported tetraphenylarsonium analog [2] . The technetium nitrogen triple bond lengths are 1.601(7) and 1.597(7) A. The X-ray structure solution for C32H72Cl4N2O4Tc of molecular weight 886.72 g mol−1: Monoclinic space group P21/n, a=15.2894(12), b=16.4321(12), c=17.9311(14) A, β=105.5100(10)°, volume=4340.9(6) A3. Solution based on 6212 independent reflections to give a final R value of 0.0701 and GOF=1.124.
THE FLAGELLAR APPARATUS OF CHRYSOLEPIDOMONAS DENDROLEPIDOTA (CHRYSOPHYCEAE), A SINGLE‐CELLED MONAD COVED WITH ORGANIC SCALES1

The flagellar apparatus of Chrysolepidomonas dedrolepidota Peters et Andersen is similar to that of other members of the Ochromonadales, Chrysophyceae. there are four microtubular roots (R1-4) and a system II fiber (= rhizoplast). the R1 root consists of three microtubules that nucleate many cytoplasmic microtubules. One compressed band of 10 or more cytoplasmic microtubules is directed black along the R1 root in an anti-parallel direction. The R2 root consists of one to two microtubules, and it extends toward the distal end of the R1 root. The R3 root consists of six (?seven) microtubules near its proximal end. The “a” and “f” microtubules of the R3 root are under the short flagellum, and the “f” microtubule loops back and under the basal body, extending down to the nucleus. The R4 root consists of one to two microtubules extending along the left side of the shot flagellum and curving under the short flagellum where it terminates near the “a” microtubule of R3 Both flagella have a transitional plate and a transitional helix with five gyres. There is a thin, second plate in the basal body at the level of the distal end of the “c” tubules of the basal body triplets. The tripartite flagellar hairs have long lateral filaments but lack short lateral filaments. We compare the flagellar apparatus with that of other members of the Ochromonadales and members of the Hydrurales and Hibberdiales.
Postoperative epidural analgesia following abdominal aortic surgery: Do the benefits justify the costs?

This study was undertaken to compare postoperative epidural analgesia (PEA) with patient-controlled analgesia (PCA) regarding complications, particularly pulmonary, death, intensive care unit and hospital stay, and hospital and physician charges. The elective consecutive infrarenal abdominal aortic procedures performed by two vascular surgeons over a 1 year period were retrospectively analyzed. Although nonrandomized, of the 80 patients reviewed, 40 received PEA and 40 received PCA. The following demographic data were obtained: age, sex, diabetes mellitus, hypertension, coronary artery disease, prior coronary revascularization, stroke, renal insufficiency, smoking, and chronic obstructive pulmonary disease. Epidural catheters were placed preoperatively and maintained for an average of 4 days postoperatively. All patients underwent routine aortic reconstruction via midline transperitoneal incisions. The demographics were similar in both groups. Likewise, surgical intensive care unit stay and complications were similar in both groups. The average length of stay in patients receiving PEA was 7.59 days, compared with 6.68 days for the PCA group. Following discharge from the hospital, no additional complications were encountered and no readmissions required during a 4-week follow-up. Average charge (hospital and physician) per patient for PEA was $2489.00 compared with $443.00 for patients receiving PCA (no physician charges generated for PCA). The results do not support the routine use of PEA following abdominal aortic operations. Savings are more than $2000.00 per patient for PCA compared with PEA.
Using the Computer To Compare Foreign and Native Language Writing Processes: A Statistical and Case Study Approach.

Writing process research has attracted significant attention in English composition studies. However, much less research exists on the relationship between foreign language (FL) and first language (L1) writing processes. This study focuses on whether university students studying a FL (in this case German) at an American university use the same processes and writing strategies in FL and L1 writing in two different genres (letter and article). Using a computerized tracking device, individual writing sessions were analyzed through statistical techniques and individual case studies. Statistical results provided evidence that students wrote less, but revised more, when writing in the FL than in the L1. In their L1, students tended to revise less in the letter genre than when writing an article. The author advocates using the computer for writing process research, given that it is an unobtrusive and efficient method of data collection and because it provides researchers with an easy way to replicate research and to share data.
Dyadic Interaction Profiles in Infancy and Preschool Intelligence.

Abstract The present study reports the results of a 2-year longitudinal study of a sample of 23 mother–infant dyads observed during a free-play interaction session when infants were 6 and 8 months of age and then assessed for language and intellectual outcomes during the second and third years of life. Analyses of interaction variables during infancy showed developmental trends across these ages in which bouts of joint attention increased but the maternal role in the initiation and maintenance of such bouts decreased. A cluster analysis of the developmental patterns of the dyads' interaction variables divided the sample into two subgroups. One of the subgroups n = 17 was characterized by the normative developmental trend described above and by high levels of joint attention at both ages. In a smaller second subgroup n = 6 , dyads were generally unsuccessful at attaining joint attention despite relatively high and consistent maternal initiation and attentional switching at both ages. Dyads in the first cluster showed significantly higher scores on the MacArthur Language Inventory at 24 months and on the Vineland Adaptive Behavior Scales and Weschler Primary Preschool Scale of Intelligence at 40 months. Differences between the clusters appeared to diverge more strongly at assessments administered later ages.
Characterization of a monomeric Escherichia coli alkaline phosphatase formed upon a single amino acid substitution.

Alkaline phosphatase (AP) from Escherichia coli as well as APs from many other organisms exist in a dimeric quaternary structure. Each monomer contains an active site located 32 A away from the active site in the second subunit. Indirect evidence has previously suggested that the monomeric form of AP is inactive. Molecular modeling studies indicated that destabilization of the dimeric interface should occur if Thr-59, located near the 2-fold axis of symmetry, were replaced by a sterically large and charged residue such as arginine. The T59R enzyme was constructed and characterized by sucrose-density gradient sedimentation, size-exclusion chromatography, and circular dichroism (CD) and compared with the previously constructed T59A enzyme. The T59A enzyme was found to exist as a dimer, whereas the T59R enzyme was found to exist as a monomer. The T59A, T59R, and wild-type APs exhibited almost identical secondary structures as judged by CD. The T59R monomeric AP has a melting temperature (Tm) of 43 °C, whereas the wild-type AP dimer has a Tm of 97 °C. The catalytic activity of the T59R enzyme was reduced by 104-fold, whereas the T59A enzyme exhibited an activity similar to that of the wild-type enzyme. The T59A and wild-type enzymes contained similar levels of zinc and magnesium, whereas the T59R enzyme has almost undetectable amounts of tightly bound metals. These results suggest that a significant conformational change occurs upon dimerization, which enhances thermal stability, metal binding, and catalysis.
Incidence, mechanisms, and severity of game-related college football injuries on FieldTurf versus natural grass: a 3-year prospective study.

BackgroundNumerous injuries have been attributed to playing on artificial turf. More recently, FieldTurf was developed to duplicate the playing characteristics of natural grass. No long-term studies have been conducted comparing game-related collegiate football injuries between the 2 playing surfaces.HypothesisCollegiate athletes do not experience any difference in the incidence, mechanisms, and severity of game-related injuries between FieldTurf and natural grass.Study DesignCohort study; Level of evidence, 2.MethodsTwenty-four universities were evaluated over 3 competitive seasons for injury incidence, injury category, time of injury, injury time loss, player position, injury mechanism, primary type of injury, grade and anatomical location of injury, type of tissue injured, trauma (head, knee, and shoulder), and environmental factors.ResultsIn sum, 465 collegiate games were evaluated for game-related football injuries sustained on FieldTurf or natural grass during 3 seasons. Overall, 230 team games (49....
Recent developments in protein and peptide parenteral delivery approaches

Discovery of insulin in the early 1900s initiated the research and development to improve the means of therapeutic protein delivery in patients. In the past decade, great emphasis has been placed on bringing protein and peptide therapeutics to market. Despite tremendous efforts, parenteral delivery still remains the major mode of administration for protein and peptide therapeutics. Other routes such as oral, nasal, pulmonary and buccal are considered more opportunistic rather than routine application. Improving biological half-life, stability and therapeutic efficacy is central to protein and peptide delivery. Several approaches have been tried in the past to improve protein and peptide in vitro/in vivo stability and performance. Approaches may be broadly categorized as chemical modification and colloidal delivery systems. In this review we have discussed various chemical approaches such as PEGylation, hyperglycosylation, mannosylation, and colloidal carriers including microparticles, nanoparticles, liposomes, carbon nanotubes and micelles for improving protein and peptide delivery. Recent developments on in situ thermosensitive gel-based protein and peptide delivery have also been described. This review summarizes recent developments on some currently existing approaches to improve stability, bioavailability and bioactivity of peptide and protein therapeutics following parenteral administration.
Terrestrial atmospheric composition from stellar occultations.

Stellar ultraviolet light transmitted through the upper mesosphere and lower thermosphere of the earth's atmosphere is primarily affected by the photoabsorption processes of ozone and molecular oxygen. The stellar ultraviolet photometers aboard the OAO-2 satellite have measured the intensity changes of several stars during occultation of the star by the earth. The measurements of the relative intensity change in certain atmospheric absorption bands are used to recover the vertical number density profiles of the absorbing species. Using the OAO-2 occultation data, the vertical number density profiles of molecular oxygen in the 100-200 km altitude region and ozone in the 60-100 km altitude region are determined.
The Instructional Benefits from Faculty Participation in Industrial Outreach

During the past twenty years, universities have significantly expanded their community service and outreach roles, including the addition of industrial outreach programs. This development has caused a need for an increased understanding of the nature and results of faculty participation in industrial outreach. This study of nineteen university-based outreach programs and 107 participating faculty found that participating faculty perceive positive impacts and outcomes for the educational and research missions of the university from their industrial outreach. Although positive perceptions and outcomes were identified, the faculty participating in this study identified barriers that must be addressed to expand the participation of faculty in industrial outreach.
Bicycle ergometry and gas exchange measurements in neuromuscular diseases.

• Using bicycle ergometry with computerized respiratory gas exchange measurements, we compared exercise capacities in patients with various neuromuscular diseases to those in normal controls. As expected, male and female patients had significantly reduced maximum work capacities (kilopond-meters per minute per kilogram of body weight) and maximal oxygen consumptions. The oxygen cost of exercise was normal in the majority of patients, although some appeared to have abnormally high oxygen consumptions during exercise. Breathing patterns during exercise, particularly in regard to onset of hyperventilation, were similar in patients and controls.
Choosing the right UPS

With the increasing variety of uninterruptible power supply (UPS) systems available, particularly at the low-pOwer end of the market, choosing a UPS can be a confusing task. This article looks at the main types of system available and offers some tips on what to look for in a UPS
High-elevation rock outcrop vegetation of the Southern Appalachian Mountains

Species composition patterns and vegetation-envi- ronment relationships were quantified for high-elevation rock outcrops of the Southern Appalachian Mountains, an infre- quent and insular habitat in a forested landscape. Outcrops occur over a wide geographic range encompassing extensive variation in both geology and climate. Geographic-scale fac- tors interact with site-scale factors to produce variation in vegetation among outcrops. Similarly, site-scale factors inter- act with micro-scale factors to produce variation in vegetation within outcrops. To provide a quantitatively-based classifica- tion of outcrop vegetation we used a TWINSPAN analysis of 154 100-m2 plots. We recognized nine communities that pri- marily correspond to different combinations of elevation, bedrock type, geography, and moisture. Within outcrops of a single bedrock type, vegetation composition of 100-m 2 plots was consistently correlated with elevation and solar radiation, but relationships to soil nutrients varied with bedrock type. Both site-scale (100 m 2 ) factors (e.g. elevation, slope, aspect, and bedrock type) and plot-scale (1-m 2 ) microsite factors (e.g. soil depth, vegetation height, soil nutrients) were strongly correlated with species composition at the 1-m 2 level. Envi- ronment can be used to predict composition more effectively for 100-m 2 plots on a single bedrock type than either across bedrock types or at a 1-m 2 scale. Composition-environment relationships resemble those described for outcrop systems from other regions with pronounced topographic relief more than they do those described for the nearby but flatter and lower-elevation outcrops of the Southeastern Piedmont. There is strong spatial autocorrelation in this community, perhaps owing to dispersal limitation. Consequently, a comprehensive conservation strategy must include reservation of both a range of geologic types and a range of geographic locations.
A tensor artificial viscosity using a mimetic finite difference algorithm

Abstract We have developed a two-dimensional tensor artificial viscosity for finite difference shock wave computations. The discrete viscosity tensor is formed by multiplying the gradient of velocity tensor by a scalar term. The scalar term is based on the form of viscosity first presented by Kurapatanko, and also contains a limiter designed to switch off the viscosity for shockless compression and rigid-body rotation. Mimetic discretizations are used to derive the form of the momentum and energy equations for a nonorthogonal grid where the viscosity tensor is evaluated at the zone edges. The advantage of the tensor viscosity is a reduction of the dependence of the solution on the relation of the grid to the flow structure.
Critical parameters in the processing of engineered stress profile glasses

A new approach to chemical strengthening is to move the maximum residual compression below the glass surface. With appropriate processing, this approach leads to strengthening and a decrease in the strength variability. This improvement in mechanical reliability is accomplished by introducing stable crack growth into the glass, which leads to multiple cracking of the glass surface prior to failure. In the current study, a fracture mechanics analysis is presented that uses a simple form for the stress profile. By determining the effect of this stress profile on the apparent fracture toughness of the material, it is possible to identify the conditions when spontaneous cracking occurs, the stress for the onset of multiple cracking and the ultimate strength of the glass. In particular, it is shown there is an important interplay between the depth of the maximum compression, the stress gradient and the magnitude of the maximum compressive stress. The current analysis is then used to define a strategy for the processing of glasses with engineered stress profiles.
Wind-Induced Hypolimnion Exchange in Lake Ontario's Kingston Basin: Potential Effects on Oxygen

Abstract The hypolimnion of Lake Ontario's Kingston basin exhibited significant oxygen depletion during 1991. The degree of hypolimnion oxygen depletion was consistent with what would be expected on the basis of morphology. No such depletion was observed in 1992, a year during which hypolimnetic currents in the channel west of Galloo Island flowed predominantly from Lake Ontario into the Kingston basin. The prevailing southwest winds during the summer of 1991 were anomalously persistent. Wind and current data from 1992 suggest that winds from the south-southeast, departures from the prevailing southwest winds, enable hypolimnetic flow from the main basin of Lake Ontario to replace the hypolimnion. This apparently failed to occur during 1991.
Sediments as sources of DDT and PCB

Abstract Despite major decreases in DDT and PCB emissions over a three year period by the dominant discharger to a coastal marine site, only minor (and very similar) decreases were observed in concentrations of these pollutants in bottom sediments and flatfish from the outfall monitoring zone. These results illustrate how persistant such chlorinated hydrocarbons can be in the marine environment once the bottom sediments have been contaminated.
A Combinatorial Proof of the Farkas-Kra Theta Function Identities and Their Generalizations

Abstract Recently, Farkas acid Kra found some cubic theta function identities from their work on automorphic forms. Shortly thereafter, Farkas and Ropeliovich were able to generalize these to p th order theta function identities using the theory of elliptic functions. We give short, elementary proofs of the cubic identities. We show that the p th order identities follow from more general relations between the coefficients of certain theta functions. Our proof is combinatorial and utilizes certain orthogonal transformations.
Cognitive performance of introverts and extraverts following acute alcohol ingestion.

Forty male medical students were randomly assigned to either an alcohol (1.32 ml/kg) or a placebo group. The 20 subjects in each group were then divided at the median into introverts and extraverts as determined by scores on the Eysenck Personality Inventory. A cognitive test, Raven's Progressive Matrices, was administered to the alcohol subjects at a blood alcohol level of 0.09 per cent and to the placebo subjects at a comparable time after drinking. Alcohol impaired performance on both Sets I and II of Raven's Progressive Matrices. Introverts and extraverts did not differ in performance on Set I administered on the ascending limb of the blood alcohol curve. A significant interaction was found on Set II (administered on the descending limb): extraverts performed more poorly than introverts in the alcohol group while extraverts performed better than introverts in the placebo group. These data support Eysenck's hypothesis that extraverts are more affected by alcohol than introverts. This difference may not become apparent until subjects are on the descending limb of the blood alcohol curve where the depressant-like effects of alcohol are the greatest.
Direct determination of molar ratios of various chemical constituents in endotoxic glycolipids in silicic acid scrapings from thin-layer chromatographic plates.

Abstract Analytical procedures are described for the determination of the ratios of nitrogen, phosphorus, hexosamine, carbohydrates, fatty acids and 2-keto-3-deoxyoctonate (KDO) in bacterial endotoxic glycolipids separated by thin-layer chromatography (TLC). The methods make it possible to carry out analyses in the presence of silicic acid to obtain the molar ratios of the chemical constituents of natural products. For some micro-determinations, such as nitrogen, phosphorus or KDO, scrapings from a single TLC plate are sufficient for carrying out the quantitative analyses.
Adolescent girls' communication with "mothers" about topical microbicides.

Abstract Study Objective Topical microbicides, a female-initiated method to protect against sexually transmitted infections (STI) and pregnancy, will only be effective if found acceptable. Mothers may have an influence on acceptability and use among adolescent girls. The current study examined the communication between girls and mothers to understand the potential predictors and nature of conversations regarding surrogate microbicide products. Design Sexually experienced girls, 14 to 21 years, were recruited for a 6-month study examining microbicide acceptability. During face-to-face interviews, qualitative data were collected regarding communication between girls and mothers. Two independent raters coded the responses, which were organized into themes. Themes were interpreted according to the conceptual understanding of mother-daughter communication. Results Fifty percent of the 171 girls with codable responses had a conversation with their mother. Higher levels of indirect parental monitoring were related to being more likely to have a conversation. Concrete events related to the study (i.e. receiving phone call from the researcher, having an appointment, or seeing the product) or inquiries by mothers appeared to promote conversation. Barriers to conversation included the private nature of the information and relationship issues between the mother and daughter. Conversations often addressed issues related to girls' participation in the study, although some conversations included global issues related to sexuality. Conclusions Girls may talk to their mothers about new products for STI prevention, and such conversations may provide opportunities to promote use.
Oblique echoes from over-dense meteor trails

Abstract Ray paths are computed for waves refracted by meteor trails having a Gaussian radial distribution of ionization density. From the spreading of initially parallel rays as they pass through the trail, a measure of reflected signal intensity vs. scattering angle is obtained; the results are presented in polar scattering diagrams, valid in the limit of large trail size. Equivalence theorems are derived relating both intensity and scattering angle for rays incident upon the trail at an arbitrary angle to the intensity and scattering angle for rays incident in the plane normal to the trail. Curves are presented showing the dependence of echo duration on forward-scatter-angle with trail orientation as parameter; it is found that the sec 2 φ law developed for under-dense trails applies to over-dense trails only if the plane of propagation contains the trail axis. If not, the effective secant exponent may be as small as 0·3. The theory is compared with McKinley and McNamara 's duration measurements. It is found that although the general agreement is satisfactory, the details of their experimental results depend on the way that winds change the trail orientation. The ray theory is also compared with Keitel 's wave theory solution. Unfortunately, he could not get wave solutions for dense trails of age greater than 0·357 per cent of the minimum echo duration. Even so, the ray solutions agree with Keitel 's results for scatter angles up to 155°, thus including all angles available to ground-based stations.
Black Male Adolescents Navigating Microaggressions in a Traditionally White Middle School: A Qualitative Study

On the basis of qualitative case study analysis, this study offers in-depth understanding of Black male middle school students' perceptions of racial microaggressions. It was found that Black male adolescents, depending on their backgrounds, are aware of different types of microaggressions. Implications for school counselors, teachers, and administrators are discussed. Basandose en analisis cualitativos de estudios de caso, este estudio ofrece un entendimiento en profundidad de las percepciones por parte de estudiantes varones Negros en la escuela media de microagresiones raciales. Se hallo que los varones Negros adolescentes, dependiendo de su origen, son conscientes de distintos tipos de microagresiones. Se discuten implicaciones para consejeros escolares, profesores y administradores.
Kinetic deuterium isotope effects operative during triplet-sensitized 1:2+2] photocyclization of - and -sesquinorbornatrienes

Abstract Triplet-sensitized excitation of 1 and 2 leads under kinetic control to quadricyclanes 3-6 where the valence isomers possessing olefinic-bound deuterium dominate by a factor of 1.11–1.16.
ON THE STRUCTURE OF STABLE DOMAINS

ABSTRACT Let be a commutative ring with identity. A regular ideal of is stable if is a projective over its ring of endomorphisms. If every regular ideal of is stable, then is said to be stable. In the first half of a two-part study, we describe the basic structural properties of stable integral domains.
Biomechanical Stability of Transverse Connectors in the Setting of a Thoracic Pedicle Subtraction Osteotomy

Abstract Background context Transverse connectors (TCs) are often used to improve the rigidity of posterior spinal instrumentation as previous investigations have suggested that TCs enhance torsional rigidity in long-segment thoracic constructs. Posterior osteotomies, such as pedicle subtraction osteotomy (PSO), are used in severe thoracic deformities and provide a significant amount of correction; as a consequence, however, PSOs also induce three-column spinal instability. In theory, augmentation of longitudinal constructs with TC after a thoracic PSO may provide additional rigidity, but the concept has not been previously evaluated. Purpose To evaluate the biomechanical contribution of TC to the rigidity of a long-segment pedicle screw-rod construct after a thoracic PSO. Study design An in vitro fresh-frozen human cadaveric biomechanical analysis. Methods Seven human cadaveric thoracic spines were prepared and instrumented from T4–T10 with bilateral pedicle screws/rods and a PSO was performed at T7. Intact range of motion (ROM) testing was performed with nondestructive loading and analyzed by loading modality (axial rotation [AR], flexion/extension [FE], and lateral bending [LB]). Range of motion analysis was performed in the unaugmented construct, the construct augmented with one TC, and the construct augmented with two TCs. Results After PSO and an unaugmented longitudinal pedicle screw-rod construct, T4–T10 (overall construct) and T6–T8 (PSO site) ROMs were significantly reduced in all planes of motion compared with intact condition (AR: 11.8° vs. 31.7°; FE: 2.4° vs. 12.3°; 3.4° vs. 17.9°, respectively, p .05). In contrast, during AR, global ROM was significantly reduced by 43% and 48% at T6–T8 (1.7° and 1.2° vs. 2.38°, respectively) after addition of one and two TCs (p Conclusions Two TCs significantly improved torsional rigidity of the entire construct and at the PSO site, with no differences in rigidity for FE and LB or with the addition of only one TC. In the setting of a PSO and long-segment pedicle screw-rod construct, augmentation with at least two TCs should be considered to improve torsional rigidity.
Greenhouse gas mitigation on marginal land: a quantitative review of the relative benefits of forest recovery versus biofuel production.

Decisions concerning future land-use/land cover change stand at the forefront of ongoing debates on how to best mitigate climate change. In this study, we compare the greenhouse gas (GHG) mitigation value over a 30-year time frame for a range of forest recovery and biofuel production scenarios on abandoned agricultural land. Carbon sequestration in recovering forests is estimated based on a statistical analysis of tropical and temperate studies on marginal land. GHGs offset by biofuel production are analyzed for five different production pathways. We find that forest recovery is superior to low-yielding biofuel production scenarios such as oil palm and corn. Biofuel production scenarios with high yields, such as sugarcane or high-yielding energy grasses, can be comparable or superior to natural forest succession and to reforestation in some cases. This result stands in contrast to previous research suggesting that restoring degraded ecosystems to their native state is generally superior to agricultural pr...
Hydroacoustic separation of rainbow smelt (Osmerus mordax) age groups in Lake Champlain

Separate assessment of young-of-year (YOY) and yearling-and-older (YAO) fish is desirable from both ecological and management perspectives. Acoustic assessments provide information on fish population size structure in the target strength (TS) distribution, but interpretation of TS distributions must be done carefully, as single age groups can produce multiple TS modes. We assessed the ability of in situ TS distributions to identify Lake Champlain rainbow smelt (Osmerus mordax) age groups in June, July, and September of 2001 using mobile and stationary surveys, knowledge of vertical distribution preferences, and predicted TS from trawl catches. YAO rainbow smelt (93–179 mm total length) had wide TS distributions between −60 and −35 dB in all 3 months with two modes at approximately −50 and −40 dB. Most stationary survey single-fish tracks attributed to YAO had targets in both TS modes and a wide TS range often over 15 dB. Between June and September, YOY rainbow smelt TS increased, but single-fish tracks were unimodal, and the TS range was smaller (6 dB). Overlap in TS attributed to YOY and YAO increased from no overlap in June (YOY TS −76 to −61 dB, 15–25 mm) to moderate overlap in July (−76 to −50 dB, 25–63 mm) to considerable overlap in September (−68 to −45 dB, 33–80 mm). In June and July, the TS distribution changed abruptly at the thermocline, indicating almost complete separation of the two groups. A more gradual TS transition was evident in September, indicating substantial overlap between YOY and YAO. Separate estimates can be obtained in September by decomposing TS overlap into components attributed to YOY and YAO rainbow smelt. However, this decomposition introduces additional uncertainty and an assessment in July or possibly August is preferable to obtain separate abundance estimates of YOY and YAO.
Making a case for an interface between quasi-experimental designs and social impact analyses

This paper describes the community impact assessment conducted after Concorde operations were initiated at Dulles International Airport. Problems in the design and conduct of this study that make causal interpretations implausible are discussed. The present authors report an improved design to eliminate these problems as well as increase the external validity of the results. A discussion of how the careful implementation of quasiexperimental designs allows for treatment-related causal interpretations to be made is also included. Finally, it is emphasized that practical application of these data make it possible to improve the implementation of the treatment in communities receiving it at a later date.
Endothelial Cell Surface Alkaline Phosphatase Activity is Induced by IL-6 Released During Wound Repair

Phosphatase activity on endothelial cell surfaces is responsible, in part, for the conversion of adenosine nucleotides to adenosine, a potent vasodilator and anti-inflammatory mediator that can protect tissues from the ischemic damage that results from injury. To evaluate whether phosphatases are actively induced by a soluble factor released following injury, the effect of tissue fluids collected from porcine or human skin wounds was tested on primary cultures of endothelial cells. Phosphatase activity increased ≈50-fold following 48-h culture in the presence of wound fluid. Inductive activity was present only in fluids collected during the inflammatory phase of wound repair. The phosphatase activity metabolized adenosine monophosphate to free phosphate and was the liver/bone/kidney alkaline phosphatase isoenzyme: activity was temperature- and levamisole-sensitive, l-phenylalanine-resistant, and linked to the cell surface via phospholipid, and migrated at a size identical to this isozyme. interleukin-6 was identified as the phosphatase-inducing factor in wound fluid and the related cytokines, leukaemia inhibiting factor, and oncostatin M, caused a similar degree of alkaline phosphatase induction. Therefore, following injury, accumulation of interleukin-6 can lead to production by alkaline phosphatase of adenosine and subsequent protection from ischemic injury.
The sensitivity theory of motivation: Implications for psychopathology

Sensitivity theory holds that people differ in both the types of reinforcement they desire and in the amounts of reinforcement they need to satiate. People who crave too much love, too much attention, too much acceptance, too much companionship, or too much of some other fundamental reinforcer are at risk for aberrant behavior because normative behavior does not produce the desired amounts of reinforcement. People who are intolerant of even everyday amounts of anxiety or frustration also are at risk for aberrant behavior. Individual differences in desired amounts of particular reinforcers may predict person-environment interactions, risk factors for psychopathology, and the occurrence of generalized and durable therapy effects versus the occurrence of relapses. Parallel predictions are made for individual differences in tolerance of aversive stimuli. Implications are discussed for applied behavior analysis, the development of psychopathology, and treatment strategies.
Influence of Surface Charge Distributions and Particle Size Distributions on Particle Attachment in Granular Media Filtration

Filtration experiments were performed with a laboratory-scale filter using spherical glass beads with 0.55 mm diameter as collectors. Suspensions were made with Min-U-Sil 5 particles, and two different methods (pH control and polymer dosing) were used for destabilization. In the pH control experiments, all particles had negative surface charge, and those with lower (absolute value) charge were selectively attached to the collectors, especially during the early stage of filtration. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. However, the ZPD of the effluent did not continue moving to more negative values during the later stages of filtration, and this result was attributed to two reasons: ripening effects and detachment of flocs. In the polymer experiments, substantial differences were found between experiments performed with negatively charged particles (underdosing) and those with positively charged particles (overdosing). With under-dosing, the results were similar to the pH control experiments (which also had negatively charged particles), but with overdosing, the effluent's ZPDs in the early stages did not overlap with those of the influent and more highly charged particles were removed more efficiently than lesser-charged particles. It is hypothesized that, despite a substantial period of pre-equilibration of media and coagulant, this equilibrium shifted when particles were also added. It was assumed that coagulant molecules previously adsorbed to the particles desorbed and subsequently attached to the filter media because of surface area differences in the particle and filter media.
NOTE ON THE REDESCRIPTION OF THE NYMPH OF THE MAYFLY RHITHROGENA VIRILIS MCDUNNOUGH 1934 (EPHEMEROPTERA: HEPTAGENIIDAE)

ABSTRACT. The mayfly Rhithrogena virilis was first described in 1934 by McDunnough in western Canada. Since its description, it has been recorded only once. We reared nymphs and provide descriptions and digital photos that may make identification of this species easier.
Four year survival in untreated AIDS related-Kaposi sarcoma (AIDS-KS) in Jos, Nigeria

Patients and methods The Jos University Teaching Hospital HIV cohort has more than 10,500 adult patients enrolled for care. We prospectively collect routine data on individuals, and during the study 175 patients presenting with AIDS-KS were followed up. We compared survival, clinical, immunologic and virologic characteristics between male and female patients receiving HAART (two NRTIs and one NNRTI). Comparison of variables between groups was by χ2 test for nominal variables. Survival was calculated from the day of enrollment until death or the date of last follow-up using Kaplan-Meier method (Figure 1).
A rating system for predicting the appearance of temik® aldicarb residues in potable water

The potential for TEMIK®; aldicarb pesticide to appear in potable water is estimated by applying a numerical indexing system. The index recognizes four basic categories of factors that affect the potential of chemical residues to occur in potable water. Values are assigned to the factors based on published data, designed laboratory tests and estimates based on knowledge about the use of the pesticide. An area with a high index number is expected to have a higher potential for aldicarb residue to appear in potable water than an area with a lower number. The index does not give quantitative values for aldicarb residue concentrations but indicates the sensitivity of an area to significant intrusion into water supplies. The system has been calibrated by adjusting scoring to reflect results of on-site monitoring from different climatic and geographical areas. The reliability of the index is believed to be comparable in accuracy to simulation modeling and has the advantage of greater adaptability to a wide variety of areas.
Oxygen dependence of respiration in rat spinotrapezius muscle in situ

The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po(2) [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po(2) dependence of oxygen consumption, Vo(2), proportional to the rate of Po(2) decrease. Fitting equations obtained from a model of heterogeneous intracellular Po(2) were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of Vo(2) on Po(2). This curve consists of two regions connected by the point for critical Po(2) of the cell (i.e., Po(2) at the sarcolemma when the center of the cell becomes anoxic). The critical Po(2) was below the Po(2) for half-maximal respiratory rate (P(50)) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 ± 6 nl O(2)/cm(3)·s and mitochondrial P(50) was k = 10.5 ± 0.8 mmHg. The range of Po(2) values inside the muscle fibers was found to be 4-5 mmHg at the critical Po(2). The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po(2) was substantially lower than the interstitial Po(2) of 53 ± 2 mmHg, a finding that indicates that Vo(2) under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue.
Angiogenin cleaves tRNA and promotes stress-induced translational repression.

Stress-induced phosphorylation of eIF2α inhibits global protein synthesis to conserve energy for repair of stress-induced damage. Stress-induced translational arrest is observed in cells expressing a nonphosphorylatable eIF2α mutant (S51A), which indicates the existence of an alternative pathway of translational control. In this paper, we show that arsenite, heat shock, or ultraviolet irradiation promotes transfer RNA (tRNA) cleavage and accumulation of tRNA-derived, stress-induced small RNAs (tiRNAs). We show that angiogenin, a secreted ribonuclease, is required for stress-induced production of tiRNAs. Knockdown of angiogenin, but not related ribonucleases, inhibits arsenite-induced tiRNA production and translational arrest. In contrast, knockdown of the angiogenin inhibitor RNH1 enhances tiRNA production and promotes arsenite-induced translational arrest. Moreover, recombinant angiogenin, but not RNase 4 or RNase A, induces tiRNA production and inhibits protein synthesis in the absence of exogenous stress. Finally, transfection of angiogenin-induced tiRNAs promotes phospho-eIF2α–independent translational arrest. Our results introduce angiogenin and tiRNAs as components of a phospho-eIF2α–independent stress response program.