cssi/SciSciGPT-SciSciNet huggingface dataset:
tudor, a posterior-group gene of Drosophila melanogaster, encodes a novel protein and an mRNA localized during mid-oogenesis

The tudor (tud) locus of Drosophila melanogaster is required during oogenesis for the formation of primordial germ cells and for normal abdominal segmentation. The tud locus was cloned, and its product was identified by Northern analysis of wild-type and tud mutant RNAs. The locus encodes a single mRNA of approximately 8.0 kb that is expressed throughout the life cycle, beginning in the early stages of germ-line development in the female. During oogenesis, tud mRNA appears to be present in the oocyte precursor within the germarial cysts, and in stages 1-3 it accumulates within the developing oocyte. The transcript is localized to the posterior half of the oocyte during oogenetic stages 4-7 but is not detectable within the ooplasm by egg deposition and throughout early embryogenesis. The tud protein has a predicted molecular mass of 285,000 daltons and has no distinctive sequence similarity to known proteins or protein structural motifs. Taken together, these results indicate that the tud product is a novel protein required during oogenesis for establishment of a functional center of morphogenetic activity in the posterior tip of the Drosophila embryo.
Class and the Economics of Crime

Then in his second semester at Eastern District High School, he gave up working in school altogether. "I don't really know why, and I don't want to rational ize about it, but it may have been that ...
Magnetic phase transition in epitaxial Ni 1 − x Fe x alloy thin films

An investigation of fcc ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}$ thin films utilizing a combination of M\"ossbauer spectroscopy and magnetometry presents clear evidence for the emergence of a low-spin antiferromagnetic state in the region of high Fe concentration, which coexists with a high-spin ferromagnetic state. The emergence of this state is observed by magnetometry as a drop in the saturation moment while M\"ossbauer spectroscopy reveals the appearance of a low-spin antiferromagnetic state. Evidence of superparamagnetic behavior indicates that the portion of the sample in the high-spin state may exist as clusters in a matrix of the low-spin state.
Immigration and Obesity Among Lower Income Blacks

Objective: Our objective was to examine the associations of nativity, immigrant generation, and language acculturation with obesity among lower income black adult men and women. Research Methods and Procedures: Data from 551 black adult men and women were collected from participants in the Healthy Directions-Health Centers Study. Race/ethnicity and nativity were self-reported. Language acculturation was defined using participants’ first language, preferred reading language, and language spoken at home. Mixed model logistic regression models were estimated to account for within-health center clustering. Results: Foreign-born blacks had a lower obesity risk, compared with all U.S.-born participants, in multivariable analyses [odds ratio (OR) = 0.57, 95% confidence interval (CI), 0.38, 0.84]. Among U.S.-born participants, those with foreign-born parents were significantly less likely to be obese than individuals with U.S.-born parents (OR = 0.54; 95% CI, 0.37, 0.80). Low-moderate language acculturation also decreased the odds of being obese (OR = 0.45; 95% CI, 0.23, 0.88). Discussion: Our findings suggest a protective effect of foreign-born status and low-moderate language acculturation on obesity risk among lower income black immigrants. These data highlight the importance of more frequently examining nativity in obesity-related research conducted among blacks.
Assessing interaction effects in linear measurement error models

Summary. In a linear model, the effect of a continuous explanatory variable may vary across groups defined by a categorical variable, and the variable itself may be subject to measurement error. This suggests a linear measurement error model with slope-by-factor interactions. The variables that are defined by such interactions are neither continuous nor discrete, and hence it is not immediately clear how to fit linear measurement error models when interactions are present. This paper gives a corollary of a theorem of Fuller for the situation of correcting measurement errors in a linear model with slope-by-factor interactions. In particular, the error-corrected estimate of the coefficients and its asymptotic variance matrix are given in a more easily assessable form. Simulation results confirm the asymptotic normality of the coefficients in finite sample cases. We apply the results to data from the Seychelles Child Development Study at age 66 months, assessing the effects of exposure to mercury through consumption of fish on child development for females and males for both prenatal and post-natal exposure.
Apoptotic markers are increased in platelets stored at 37 degrees C.

Background PLTs for transfusion lose viability during storage in blood banking. This loss of viability is accelerated at 37 degrees C, as is the risk of bacterial contamination, and has led to the selection of 22 degrees C as the routine storage temperature. Because PLTs contain an intact apoptotic mechanism, we sought to determine whether PLTs undergo apoptosis during storage and whether storage at 37 degrees C accelerated this process. Study design and methods PLT-rich plasma from PLT concentrates was stored at 37 or 22 degrees C in small aliquots or whole bags, with and without cell-permeable caspase inhibitors. Number of PLTs, pH, LDH level, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium activity were analyzed over time. PLT lysates were prepared and tested for the presence and activation of apoptotic proteins by enzyme assay and Western blotting. Results PLT viability was greatly reduced after 1 to 2 days of storage at 37 degrees C; however, signs of apoptosis were evident by 3 hours after temperature shift. In temperature-stressed PLTs only, a gradual rise in caspase-3 activity was detected that correlated with the appearance of the 17- to 20-kDa cleavage products of caspase-3. Gelsolin, a caspase-3 substrate, underwent cleavage within the same time frame. Bcl-xL and caspase-2 also declined significantly; caspase-9 activity rose. Specific caspase inhibitors could prevent caspase activation but did not improve PLT cellular viability at 37 degrees C. Conclusions PLTs contain apoptotic proteins that are activated during PLT storage at 37 degrees C and may account for the rapid decline in PLT cellular viability. Although ineffective here, inhibition of PLT apoptosis may improve PLT cellular viability.
Life Changing: The Experience of Rape-Crisis Work

Sexual violence has been studied extensively in the social work literature. However,the experiences of social workers in organizations that serve clients who are victimsof sexual violence have been given limited attention. This article presents the findings of a qualitative study that explored the experiences of 21 women employees ofrape-crisis programs. The findings suggest that social work with such clientspresented the workers with a host of emotional and existential challenges, such asincreased feelings of vulnerability as women, diminished trust in others, andquestioning the overall goodness of society.
The Single Category Implicit Association Test as a measure of implicit social cognition.

The Single Category Implicit Association Test (SC-IAT) is a modification of the Implicit Association Test that measures the strength of evaluative associations with a single attitude object. Across 3 different attitude domains--soda brand preferences, self-esteem, and racial attitudes--the authors found evidence that the SC-IAT is internally consistent and makes unique contributions in the ability to understand implicit social cognition. In a 4th study, the authors investigated the susceptibility of the SC-IAT to faking or self-presentational concerns. Once participants with high error rates were removed, no significant self-presentation effect was observed. These results provide initial evidence for the reliability and validity of the SC-IAT as an individual difference measure of implicit social cognition.
Tuning the electrical property via defect engineering of single layer MoS2 by oxygen plasma

We have demonstrated that the electrical property of single-layer molybdenum disulfide (MoS2) can be significantly tuned from the semiconducting to the insulating regime via controlled exposure to oxygen plasma. The mobility, on-current and resistance of single-layer MoS2 devices were varied by up to four orders of magnitude by controlling the plasma exposure time. Raman spectroscopy, X-ray photoelectron spectroscopy and density functional theory studies suggest that the significant variation of electronic properties is caused by the creation of insulating MoO3-rich disordered domains in the MoS2 sheet upon oxygen plasma exposure, leading to an exponential variation of resistance and mobility as a function of plasma exposure time. The resistance variation calculated using an effective medium model is in excellent agreement with the measurements. The simple approach described here can be used for the fabrication of tunable two-dimensional nanodevices based on MoS2 and other transition metal dichalcogenides.
The influence of protein malnutrition on ileal permeability to macromolecules in the rat.

Ileal absorption of intact protein was assessed in groups of control and protein-deficient rats during a 5-month period of dietary protein restriction. At monthly intervals following diet initiation, 3 animals from both the control and deficient groups were administered horseradish peroxidase via ligated ileal loops either 15, 45 or 90 minutes before loop excision and processing for light and electron microscopy. Morphological evaluations revealed no change in pinocytotic activity during the 5 months of progressive protein malnutrition. After 3 months, however, partial deterioration of mucosal structure was observed with apparent separation of apical intercellular junctions and movement of peroxidase molecules directly between cells. These observations in the ileum are compared to previous findings in the jejunum. It is suggested that ileal and jejunal absorptive cells respond uniquely to protein deprivation but that eventual junctional deterioration occurs in both regions with potential detrimental consequences for the host.
Knowledge-Based Expert System for Ballscrew Grinding

This paper discusses the ballscrew grinding process and provides a newly structured knowledge-based expert system (KBES) developed to automate the process based on fuzzy pattern recognition techniques for shape control with recommendations for further optimization considering practical machining constraints. The KBES offers several advantages including the use of semiskilled operators who can monitor several machines simultaneously, the consistent production of high quality parts, and the significant reduction in cycle time due to automatic adjustment of steadies. A new stepper motor steady design and in-process measuring system are also described.
Inhalation Toxicology of 1,4-Butanediol

Abstract1,4-Butanediol is a clear, slightly viscous liquid with a low vapor pressure used in manufacturing polyester glycols and polyurethanes. The material has a low order of acute inhalation toxicity with a 4-h ALC of 15 mg/l in male rats. In the repeated dose study, groups of 10 male Crl:CD rats were exposed nose-only, 6 h/day, 5 days/wk for 2 wk to aerosol concentrations of either 0, 0.20, 1.7, or 5.2 mg/l. Rats were given pathological, urinalysis, and clinical chemical examinations after the last (tenth) exposure and after a 2-wk recovery period. No adverse effects were observed in rats exposed to either 0.20 or 1.1 mg/l. Rats exposed to 5.2 mg/l had depressed body weight evident after the third exposure. After 10 exposures, these rats had increased erythrocyte count and hematocrits and decreased serum cholesterol concentrations. Pathological examination showed slight atrophy of lymphoid cells in the thymus and depressed mean heart weights in these rats. No adverse effects were observed after 2 wk of...
Effect of polybrominated biphenyls on hepatic microsomal metabolism of estrogens and uterotropic action of administered estrogen in rats

Perinatal exposure to polybrominated biphenyls (PBBs) increased the hepatic microsomal metabolism of estradiol, estrone, and ethynylestradiol in vitro. Pretreatment with PBBs decreased the effect of estradiol administered exogenously on uterine estrogen cytosolic receptor concentration. The effect of exogenous estradiol on uterine weight and uterine RNA content was also reduced by perinatal exposure to PBBs. Therefore, metabolism of estrogens is altered by PBBs.
On the determinacy of games on ordinals

Let λ be an ordinal and A ⊆ λ^ω x λ^ω. As usual we associate with it the game G(A;λ): I II I and II alternatively ξ0 η0 play ξ0, η0, ξ1,η1,.... from λ; ξ1 I wins iff (ξ, ή) eA. η1 ξ ή.
Explaining Japan's Fragile Premierships in the Post-Koizumi Era

After Prime Minister Junichiro Koizumi's highly successful rule, Japan saw the five short-lived premierships – Shinzo Abe, Yasuo Fukuda, Taro Aso, Yukio Hatoyama, and Naoto Kan – over the period of five years (2006-11). This article aims to identify the causes of this unusually high frequency of Japan's leadership changes in recent times. Specifically, it finds that all post-Koizumi prime ministers lost power after a short tenure by following the same pattern of demise that was characterized by a rapid fall of approval rate in the media's polls. It argues that they fell into this pattern of failure for the same three reasons: their failure in economic policy; their poor leadership ability derived from the vanishing of the traditional career path to premiership; their unstable intraparty foothold caused by the transition from candidate-centered election to party-centered election. It argues that the politics under the Koizumi and post-Koizumi cabinets share important undercurrents despite their apparent differences.
Optical Nanoprobes for Biosensing and Therapy

The sol-gel based oxygen nanoprobe that provides for quantitative intracellular measurement of dissolved oxygen in living cells provides a compelling example of the use of these biologically-compatible nanoplatforms for noninvasive monitoring function in living cells. Photonic Explorers for Bioanalysis with Biologically Localized Embedding (PEBBLEs) are flexible polymer nanoplatforms that encapsulate sensing elements in a biocompatible format for quantitative measurement of intracellular ions or small molecules. These biosensors capitalize on micelle or condensation/hydrolysis techniques that allow for nanoscale fabrication of polyvinyl chloride, polydecyl methacrylate, polyacrylamide hydrogels, sol-gels or organically-modified silicates with controlled diameters in the range 20-250 nm
Ontogeny of the sexually dimorphic area of the gerbil hypothalamus

Abstract The sexually dimorphic area (SDA) of the gerbil hypothalamus is a set of cell groups in the medial preoptic area that is essential for masculine sexual behavior and implicated in the hormonal control of scent marking and ultrasound production. The adult SDA shrinks after gonadectomy unless the gerbils receive testosterone. So does the SDA pars compacta , a small cell group in the SDA of males that is seldom seen in females. Here, development of the SDA and SDApc, and of a second, small, compact cell group, the cmSDApc, that lies caudal and medial to the SDApc, is described. Development of the SDApc and cmSDApc was studied quantitatively by assessing their incidence and volume in both sexes from birth (PND 1) to adulthood (PND 150). The volume of the entire SDA was studied from PND 45 to 150. In male gerbils, puberty begins around PND 40 and is complete by PND 90–120. The male SDA enlarged relative to the cross-sectional area of the hypothalamus as puberty began, but the female SDA did not. The SDApc was present in virtually all gerbils at birth and was the same size in both sexes. Over the next two weeks, the SDApcs of females disappeared while those of males persisted and doubled in size. Like the SDApc, the cmSDApc was larger and more common in males than in females, but it became smaller and less prevalent in both sexes during the first two weeks after birth.
Orville Gilbert Brim: Icon of Generativity

The purpose of this collection of essays, written by five different individuals, is to highlight the many ways in which Bert Brim nurtured the careers and life‐course development of others. As elaborated by David Almeida, Margie Lachman, Nadine Marks, Dan Mroczek, and Carol Ryff, the ways in which he practiced generativity were richly attuned to the interests and talents of each individual with whom he worked. Collectively, these personal recollections underscore the remarkable scope of his intellectual guidance and contribution to the field, as well as his fundamental goodness as a mentor, colleague, and friend.
Reactive oxygen species, ABA and nitric oxide interactions on the germination of warm-season C4-grasses

Hydrogen peroxide (H2O2) as a source of reactive oxygen species (ROS) signiWcantly stimulated ger- mination of switchgrass (Panicum virgatum L.) seeds with an optimal concentration of 20 mM at both 25 and 35°C. For non-dormant switchgrass seeds exhibiting diVerent levels of germination, treatment with H 2 O 2 resulted in rapid germination (<3 days) of all germinable seeds as compared to seeds placed on water. Exposure to 20 mM H 2 O 2 elicited simultaneous growth of the root and shoot system, resulting in more uniform seedling development. Seeds of big bluestem (Andropogon gerardii Vitman) and indiangrass (Sorghastrum nutans (L.) Nash) also responded positively to H2O2 treatment, indicating the universality of the eVect of H 2 O 2 on seed germination in warm-season prairie grasses. For switchgrass seeds, abscisic acid (ABA) and the NADPH-oxidase inhibitor, diphenyleneiodonium (DPI) at 20 M retarded germination (radicle emergence), stunted root growth and partially inhibited NADPH-oxidase activ- ity in seeds. H2O2 reversed the inhibitory eVects of DPI and ABA on germination and coleoptile elongation, but did not overcome DPI inhibition of root elongation. Treatment with H 2 O 2 appeared to enhance endogenous production of nitric oxide, and a scavenger of nitric oxide abolished the perox- ide-responsive stimulation of switchgrass seed germination. The activities and levels of several proteins changed earlier in seeds imbibed on H 2 O 2 as compared to seeds maintained on water or on ABA. These data demonstrate that seed ger- mination of warm-season grasses is signiWcantly responsive to oxidative conditions and highlights the complex inter- play between seed redox status, ABA, ROS and NO in this system.
Data integration through database federation

In a large modern enterprise, it is almost inevitable that different parts of the organization will use different systems to produce, store, and search their critical data. Yet, it is only by combining the information from these various systems that the enterprise can realize the full value of the data they contain. Database federation is one approach to data integration in which middleware, consisting of a relational database management system, provides uniform access to a number of heterogeneous data sources. In this paper, we describe the basics of database federation, introduce several styles of database federation, and outline the conditions under which each style of federation should be used. We discuss the benefits of an information integration solution based on database technology, and we demonstrate the utility of the database federation approach through a number of usage scenarios involving IBM's DB2 product.
Fate of mutagenic activity during conventional treatment of municipal wastewater sludge

The mutagenic activity of wastewater was followed during conventional activated sludge treatment at a municipal plant. Raw wastewater was initially screened for mutagenic potential, using the AmesSalmonella/mammalian microsomal test and employer tester strains. The combined raw wastewater produced dose-related mutagenic responses in the presence of S9 metabolic activation. Raw wastewater from domestic sources alone was not mutagenic. Mutagenic activity was observed throughout the treatment process. Activated sludge prior to chlorination contained the highest specific mutagenic activity. Chlorination decreased the specific mutagenic activity at pH 11. Mutagenic activity in municipal wastewater containing industrial discharges is not removed by conventional treatment processes and can be enhanced by activated sludge treatment.
Laparoscopic Intussuscepting Pancreaticojejunostomy

Perhaps the greatest barrier to adoption of laparoscopic pancreaticoduodenectomy by experienced pancreatic surgeons is the technical challenge of constructing the pancreaticojejunostomy (PJ). The authors present a less demanding PJ technique they have developed that creates an end-to-end intussuscepting anastomosis using a running monofilament suture. This method reduces technical complexity and operative time while producing acceptably comparable outcomes.
High-energy inclusive annihilation processes. II. Quantum chromodynamics

A leading logarithm sum is performed for the structure functions for the inclusive e/sup +/e/sup -/ annihilation process in quantum chromodynamics in a class of axial gauges via a Bethe-Salpeter equation. Despite the degeneracies due to the presence of massless constituents, a partonlike space-time picture prevails. The invariant-mass scales for subprocesses are strongly ordered and hadronization takes place only when the energy of the parton is sufficiently attenuated. This leads to the factorization of long- and short-distance phenomena in the moments of the structure functions. The final result is a field-theoretic justification of the Altarelli-Parisi equation.
An Integrated Linkage, Chromosome, and Genome Map for the Yellow Fever Mosquito Aedes aegypti

Background Aedes aegypti, the yellow fever mosquito, is an efficient vector of arboviruses and a convenient model system for laboratory research. Extensive linkage mapping of morphological and molecular markers localized a number of quantitative trait loci (QTLs) related to the mosquito's ability to transmit various pathogens. However, linking the QTLs to Ae. aegypti chromosomes and genomic sequences has been challenging because of the poor quality of polytene chromosomes and the highly fragmented genome assembly for this species.
GABAA receptor subtypes : ligand binding heterogeneity demonstrated by photoaffinity labeling and autoradiography

Heterogeneity of binding affinities for a variety of ligands was observed for gamma-aminobutyric acid type A (GABAA) receptors in the rat CNS, at both GABA and benzodiazepine recognition sites. Photoaffinity labeling by [3H]flunitrazepam and [3H]muscimol to affinity column-purified receptor proteins was examined by gel electrophoresis in sodium dodecyl sulfate. Anesthetic barbiturates (pentobarbital) and steroids (alphaxalone) both differentially stimulated the incorporation of [3H]flunitrazepam more so into the 51-kDa alpha 1 subunit than into the 53-kDa alpha 2 polypeptide, and incorporation of [3H]muscimol into the 55-kDa beta 2 subunit more so than the 58-kDa beta 3 polypeptide. Binding to these polypeptides was also affected differentially by other allosteric modulators and competitive inhibitors, including the benzodiazepine "type 1" selective ligand CL218,872. Heterogeneity in affinity of this drug for the single 51-kDa alpha 1 polypeptide strongly suggests that type I receptors, like type II, are heterogeneous. In brain sections, the extent of enhancement of [3H]muscimol binding showed significant regional variation, similar for both steroids and barbiturates, and the GABA analogues THIP and taurine inhibited muscimol binding with regional variations in affinity that were almost opposites of each other. Modulation of [3H]flunitrazepam binding by steroids, barbiturates, and THIP significantly varied with regions. Taken together, ligand binding heterogeneity exhibited by photoaffinity labeling and autoradiography demonstrate the existence of multiple pharmacological-binding subtypes resulting from the combination of multiple polypeptide gene products into several oligomeric isoreceptors. Comparison of the regional distribution of binding subtypes with that of different subunit gene products allows the following conclusions about possible subunit compositions of native pharmacological receptor subtypes present in the brain: Benzodiazepine pharmacology of the oligomeric receptor isoforms is dependent on the nature of alpha and subunits other than alpha, GABA-benzodiazepine coupling is dependent on the nature of the alpha subunits, GABA site pharmacology is dependent on the nature of the beta subunits, and several subunits including alpha and beta contribute to the degree of sensitivity to steroids and barbiturates. Finally, the presence of discrete subunits may be necessary but is not sufficient to postulate a defined pharmacological property.
Knee loading accelerates bone healing in mice.

Knee loading is an anabolic loading modality that applies lateral loads to the knee. This study shows that loads applied to the proximal tibial epiphysis stimulate healing of surgically generated wounds in the tibial diaphysis. Introduction: Wound healing is sensitive to mechanical stimulation such as various forms of stress and different magnitudes of strain. Knee loading has been shown to induce anabolic responses to murine tibias and femora when a strain of 10–20 μstrain is applied at the site of new bone formation. The object of this study was to address a question: does knee loading accelerate closure of open wounds in the tibia? Material and Methods: Fifty-three C57/BL/6 female mice were used. A surgical wound (0.5 mm in diameter) was generated in the left tibia (loaded) and the right tibia (sham-loaded control). From the fourth postoperative day, knee loading was performed to the left knee with a custom-made piezoelectric loader for 3 min/d for 3 consecutive days. The peak-to-peak force was 0.5 N. Animals were killed 1, 2, or 3 wk after surgery, and the healing process was evaluated with μCT, pQCT, and bone histomorphometry with calcein labeling. Results: The measured strain was <20 μstrain with 0.5-N force regardless of the presence or absence of surgical wounds. Compared with sham-loaded controls, the results showed load-driven acceleration of wound healing. First, μCT data revealed that knee loading reduced the size of surgical wounds by 13% (p < 0.01; 1 wk), 25% (p < 0.001; 2 wk), and 15% (p < 0.01; 3 wk). Second, pQCT data indicated that total BMD and BMC and cortical BMD and BMC were significantly increased in the third postoperative week. Last, bone histomorphometry revealed that bone formation was stimulated from the site proximal (close to the knee) to the wound. Conclusions: The reparative and remodeling phases of wound healing were enhanced by loads applied to the knee without inducing significant in situ strain at the site of wounds. Noninvasive knee loading might therefore be useful clinically to stimulate bone healing in the entire tibia along its length (including cast immobilized wounds).
Magnetic Models of the Brown Dwarfs HD 130948b and HD 130948c

Dynamical masses have been obtained by Dupuy et al. for the brown dwarf binary HD 130948BC. The components have luminosities log (L/L ☉) of –3.82 and –3.90, and masses of 0.0555 and 0.0530 M ☉. In a luminosity-age diagram, Dupuy et al. found that L bol for both B and C are brighter than theoretical tracks by factors of 2-3, if the age of the system is as old as their estimate of 0.79 Gyr (based on gyrochronology). Here, we apply our model of magnetic convection, in which the onset of convection is impeded in the presence of a vertical magnetic field: our goal is to replicate the observed properties not only in the luminosity-age diagram, but simultaneously in the T eff -age diagram and in the H–R diagram. Expressing the internal magnetic pressure as a fraction δ of the gas pressure, we obtain evolutionary tracks which fit both stars in an H–R diagram provided that δ lies in the range 0.007-0.038. With such values of δ, our models replicate the observed luminosities of both B and C, provided that the age is no larger than ~0.39 Gyr. This is significantly younger than the mean age estimated by Dupuy et al. for the primary star in the system, HD 130948A. However, there is sufficient uncertainty in the empirical parameters that an age as young as the one suggested by our magnetic models (~0.39 Gyr) is marginally within the permitted range.
Classroom Environments and Middle School Students' Views of Science

Abstract This study identified classroom environmental variables related to student views of science. As a replication study, it adds to a growing empirical base indicating that student views of certain academic subjects are determined, in part, by the classroom environment. The cluster analysis technique resulted in the formation of three types of classroom environments, very dissimilar on most of the environmental factors of the Classroom Environment Scale. The finding indicates that there is a wide variety of science classroom environments, teaching philosophies, and teaching expertise at these grades. In classrooms with high levels of student involvement, teacher support, group affiliation, order and organization, and teacher innovation, student attitudes toward science were highest. These findings are discussed in relation to other research in this area.
New instabilities in Wigner-Dyson lattices

Binary NaCl and CsCl Wigner-Dyson lattices have been found to exhibit a new instability (mode-softening) at critical values of the charge ratio of the two species. These occur for transverse-acoustic vibrational modes with wave vector in the [110] direction in CsCl structure (and polarization in the [001] direction) at the first Brillouin-zone boundary and in the [100] direction in NaCl structure at the zone boundary (point $M$ for CsCl and point $X$ for NaCl in reciprocal-lattice space). These instabilities leave a gap in the charge-ratio parameter range in which the only currently known locally stable structure consists of segregated bcc lattices for the two species.
Minors of 3-Connected Matroids

In [5] it was shown that if M is a 3-connected matroid with a minor isomorphic to U24, then every pair of elements of M are in a U24 minor. The proof was fairly complicated. Here we derive that theorem from a more general result. We show that to test whether U24 (or any other 3-connected matroid N) has the property described above, it is only necessary to test that it works for those matroids M with 5 (or more generally, |E (N)| + 1) elements. This is essentially a lemma which will be used in a subsequent paper.
Procedures Documentation Ought to be Illuminative, Not Just Archival:

The article starts by comparing the original and the current status of procedures documentation, a business communication genre. Seen as merely archival afterthoughts, procedures manuals have turned into neglected tools that are rarely used even though well-written current documentation can play many useful roles. Although speculating about the possible reasons for the decline, the article does not try to trace its sources; nor does it merely advocate a greater respect for the genre. Instead, this article seeks to change the very perception of what the genre ought to be by looking not only at the end product being created but also at the process that created it. The justification for such a shift lies in the changes taking place in the global environment, in what are coming to be seen as effective management practices, and in emergent information technology. Changing the perception of how the documentation process is viewed can help make it an occasion for institutional learning. That such a shift in perc...
Radio Occultation Studies of the Venus Atmosphere with the Magellan Spacecraft: 2. Results from the October 1991 Experiments

On October 5 and 6, 1991, three dual-frequency ingress radio occultation experiments were conducted at Venus during consecutive orbits of the Magellan spacecraft. The radio signals probed a region of the atmosphere near 65 deg N, with a solar zenith angle of 108 deg, reaching below 35 km at 3.6 cm, and below 34 km at 13 cm (above a mean radius of 6052 km). The high effective isotropic radiated power (EIRP) of the Magellan spacecraft and highly successful attitude maneuvers allowed these signals to probe deeper than any previous radio occultation experiment and also resulted in the most accurate thermal and sulfuric acid vapor abundance profiles ever obtained at Venus through radio occultation techniques. The performance of the spacecraft and the experiment design are discussed in an accompanying paper. Average electron density profiles retrieved from the data possess peaks between 2600 and 6000/cu cm, well below typical values of 10,000/cu cm retrieved in 1979 by Pioneer Venus at similar solar zenith angles. Other basic results include vertical profiles of temperature, pressure, and density in the neutral atmosphere, 13- and 3.6-cm absorpttivity, and H2SO4 (g) abundance below the main cloud layer. H2SO4 (g) becomes significant below 50 km, reaching peaks between 18 and 24 ppm near 39 km before dropping precipitously below 38 km. These sharp decreases confirm the thermal decomposition of sulfuric acid vapor below 39 km. Since the Venus atmosphere rotated approximately 10 deg between experiments, the data contain information about the horizontal variability of the atmosphere. All derived profiles exhibit significant variations from orbit to orbit, indicating the presence of dynamical processes between 33 and 200 km. In particular, the orbit-to-orbit variations in temperature and in H2SO4 (g) abundance appear to be correlated, suggesting that a common mechanism may be responsible for the observed spatial variations.
The Energy Levels of Sodium Chloride

An energy-level scheme is given for sodium chloride. Its predictions are compared with observations in the ultraviolet and x-ray regions and color-center phenomena.
Studies of protoplast culture types and plant regeneration from callusderived protoplasts of Asparagus officinalis L. cv. Lucullus 234

Plating efficiency and colony formation of callus-derived protoplasts of Asparagus officinalis L. cv. Lucullus 234 differed significantly with different protoplast culture media and types of culture. Osmotic conditions and hormone concentrations of liquid media produced the greatest influence on plating efficiency and colony formation in bead culture. Protoplasts grew best in bead culture with a solid modified Kao & Michayluk protoplast culture medium (KM) supplemented with 0.5 mg l−1 α-naphthaleneacetic acid (NAA), 0.5 mg l−1 2,4-dichlorophenoxyacetic acid (2,4-D), 0.5 mg l−1 kinetin, and 0.6% agarose (KM6) and a liquid modified KM medium differing from KM6 medium in sugar content, having 0.18 M sucrose and 0.18 M mannitol (A8). An average plating efficiency of 19.1% and colony formation of 15.5% was obtained one week after isolation in bead culture with the KM6 and A8 media. The highest average shoot regeneration of 92.3% was obtained with a Murashige & Skoog medium (MS) containing 0.125 mg l−1 NAA, 0.125 mg l−1 2,4-D, 0.25 mg l−1 6-benzylaminopurine (6-BAP) and 3% sucrose. Plants have been regenerated and transferred to the greenhouse.
Angiopoietin-2 Secretion by Endothelial Cell Exosomes: REGULATION BY THE PHOSPHATIDYLINOSITOL 3-KINASE (PI3K)/Akt/ENDOTHELIAL NITRIC OXIDE SYNTHASE (eNOS) AND SYNDECAN-4/SYNTENIN PATHWAYS*

Angiopoietin-2 (Ang2) is an extracellular protein and one of the principal ligands of Tie2 receptor that is involved in the regulation of vascular integrity, quiescence, and inflammation. The mode of secretion of Ang2 has never been established, however. Here, we provide evidence that Ang2 is secreted from endothelial cells via exosomes and that this process is inhibited by the PI3K/Akt/endothelial nitric oxide synthase (eNOS) signaling pathway, whereas it is positively regulated by the syndecan-4/syntenin pathway. Vascular defects in Akt1 null mice arise, in part, because of excessive Ang2 secretion and can be rescued by the syndecan-4 knock-out that reduces extracellular Ang2 levels. This novel mechanism connects three critical signaling pathways: angiopoietin/Tie2, PI3K/Akt/eNOS, and syndecan/syntenin, which play important roles in vascular growth and stabilization.
Natural control of spider mites on wine grape varieties in northern California.

Metaseiulus occidentalis (Nesbitt) was found to be capable of controlling Tetranychus pacificus McGregor populations in vineyards not subject to annual pesticidal treatments. The presence of Eotetranychus willamettei (McGregor) as an alternative prey is believed to be a critical factor in the ability of M. occidentalis to control T. pacificus . The presence of E. willamettei allows early season increase of M. occidentalis populations and season-long control of T. pacificus . Natural control of T. pacificus appears to have a seasonal carryover, since vines on which T. pacificus were controlled one year supported fewer spider mites and displayed improved vigor the following year even in the absence of predators.
Microcrystalline properties and phase transition behavior of tetragonal Pb(ZrxTi1−x)O3

Abstract The microcrystalline properties and ferroelectric phase transition in Pb(Zr x Ti 1− x )O 3 (PZT) were investigated. Chemically derived powders prepared at moderate temperatures showed large non-uniform strains sufficient to completely suppress the characteristic anomaly in specific heat at the transition. It was proposed that lattice defects interacting with the spontaneous polarization were responsible for this behavior.
Measurement of Retinal Blood Velocity and Flow Rate in Primates Using a Liposomedye System

A recently developed liposome-dye method was used to make quantitative measurements of blood velocity and volumetric flow rates in the retina of the rhesus monkey. After systemic injection of a liposome-encapsulated fluorescent dye (calcein), the release of a bolus of the dye in the retina was triggered by an ophthalmic argon laser. Initially, calcein was entrapped at a high concentration and the fluorescence of the dye in the lipid vesicle was quenched. After laser exposure, the liposomes released a bolus of dye at the laser exposure site in a specific vessel of the retina. The released dye formed a well-defined, fluorescent wavefront in the exposed artery or vein. By measuring the distance the dye traveled in the vein over a set time interval, it was possible to measure blood velocity in retinal vessels of various diameters, and to calculate volumetric flow rates in those vessels.
Left heart opacification with peripheral venous injection of a new saccharide echo contrast agent in dogs

Abstract Opacification of the left heart chambers after venous injection of echo contrast agents with transpulmonary capabilities has been difficult to achieve because of a lack of availability of a biodegradable nontoxic agent that produces uniformly small microbubbles. SHU-508 is a new saccharide echo contrast agent that produces bubble sizes from 2 to 8 μm in diameter, capable of traversing the pulmonary capillary bed and resulting in left heart contrast. The echo intensity produced by this agent was compared with that of agitated saline solution, indocyanine green and SHU-454 (another experimental saccharide agent for right-sided contrast) during 136 injections in eight dogs. Videotaped two-dimensional echographic images were digitized and analyzed with the use of videodensitometry for peak right and left ventricular intensity, pulmonary transit times and time of persistence of contrast. The highest right ventricular intensity value (3,594 ± 1,393) was achieved with SHU-508 (p Left ventricular contrast with SHU-508 was visually evident in all 42 injections, whereas the peak left ventricular intensity was 35% as bright as that produced in the right ventricle by the same agent. Peak left ventricular intensity values from SHU-508 were compared with those from agitated saline solution injected from the pulmonary capillary wedge position in four dogs. SHU-508 produced brighter left ventricular intensity (1,281 ± 607) compared with that obtained with the saline-wedge technique (p Thus, SHU-508 is a new saccharide echo contrast agent that produces effective opacification of the left ventricular cavity after peripheral venous injection in dogs.
The neuroendocrine products of intestinal carcinoids. An immunoperoxidase study of 35 carcinoid tumors stained for serotonin and eight polypeptide hormones

The intestinal carcinoid tumors of 26 patients were stained for the presence of serotonin, gastrin, somatostatin, motilin, secretin, glucagon, pancreatic polypeptide, ACTH, and neurotensin. Argentaffin and argyrophil stains were also performed in all cases. Thirty-five separate tumors (counting metastases and multiple primaries) from the 26 patients were studied. Serotonin was present in 30 of the 35 tumors. Nineteen tumors contained serotonin only. Fourteen tumors contained multiple neuroendocrine products. One tumor contained gastrin only. One tumor did not stain immunohistochemically, but was argyrophilic. Metastatic deposits were studied in nine patients. Some metastases produced the identical neuroendocrine products as the primary tumor, whereas others produced either additional or fewer hormones than the primary tumor. Moreover, different metastases from the same primary tumor were observed to produce different hormones. Argyrophilic cells were present in all cases and were much more numerous than cells staining by immunohistochemistry. Argyrophilic cells probably contain monoamines and polypeptide hormones in addition to those studied in this series. The argyrophil stain was the best general stain in this study for the demonstration of neuroendocrine cells. Argentaffin staining was negative in ten cases that were serotonin positive and two argentaffin positive cases were serotonin negative. The carcinoid syndrome, as clinically defined by the presence of flushing and diarrhea, was noted in five patients, all of whom had serotonin-containing small bowel carcinoids. Endocrine-related symptoms were not clinically appreciated in the remaining patients.
The nature of crystalline material in tissues of Lignac-Fanconi's disease.

Summary The nature of crystals in tissues of Lignac-Fanconi's disease has been investigated with the help of pure tyrosinase, by thermoanalysis, by determination of refractive indices and by the ultraviolet spectra. It was conclusively shown that tyrosine crystals were absent in all examined sections. Our findings are consistent with the crystals consisting only of L-cystine. La nature des cristaux dans les tissus de la maladie de Lignac-Fanconi a ete examinee avec l'aide de la tyrosinase pure, par la thermoanalyse, par la determination des index refractaires et par des spectrogrammes ultraviolets. On a demontre avec certitude que des cristaux de tyrosine etaient absents dans toutes les coupes examinees. Nos resultats sont en bon agrement avec la consistence des cristaux de la L-cystine seule.
Archaeology as Anthropology

It is argued that archaeology has made few contributions to the general field of anthropology with regard to explaining cultural similarities and differences. One major factor contributing to this lack is asserted to be the tendency to treat artifacts as equal and comparable traits which can be explained within a single model of culture change and modification. It is suggested that “material culture” can and does represent the structure of the total cultural system, and that explanations of differences and similarities between certain classes of material culture are inappropriate and inadequate as explanations for such observations within other classes of items. Similarly, change in the total cultural system must be viewed in an adaptive context both social and environmental, not whimsically viewed as the result of “influences,” “stimuli,” or even “migrations” between and among geographically defined units. Three major functional sub-classes of material culture are discussed: technomic, socio-technic, and ideo-technic, as well as stylistic formal properties which cross-cut these categories. In general terms these recognized classes of materials are discussed with regard to the processes of change within each class. Using the above distinctions in what is termed a systemic approach, the problem of the appearance and changing utilization of native copper in eastern North America is discussed. Hypotheses resulting from the application of the systemic approach are: (1) the initial appearance of native copper implements is in the context of the production of socio-technic items; (2) the increased production of socio-technic items in the late Archaic period is related to an increase in population following the shift to the exploitation of aquatic resources roughly coincident with the Nipissing high water stage of the ancestral Great Lakes; (3) this correlation is explicable in the increased selective pressures favoring material means of status communication once populations had increased to the point that personal recognition was no longer a workable basis for differential role behavior; (4) the general shift in later periods from formally “utilitarian” items to the manufacture of formally “nonutilitarian” items of copper is explicable in the postulated shift from purely egalitarian to increasingly nonegalitarian means of status attainment.
Arithmetic, Geometric and Harmonic Sequences

Stephen Wassell replies to the question posed by geometer Marcus the Marinite: if one can define arithmetic and geometric sequences, can one define a harmonic sequence?
Correlations between optical properties, microstructure, and processing conditions of Aluminum nitride thin films fabricated by pulsed laser deposition

Abstract Aluminum nitride (AlN) films were deposited using pulsed laser deposition (PLD) onto sapphire (0001) substrates with varying processing conditions (temperature, pressure, and laser fluence). We have studied the dependence of optical properties, structural properties and their correlations for these AlN films. The optical transmission spectra of the produced films were measured, and a numerical procedure was applied to accurately determine the optical constants for films of non-uniform thickness. The microstructure and texture of the films were studied using various X-ray diffraction techniques. The real part of the refractive index was found to not vary significantly with processing parameters, but absorption was found to be strongly dependent on the deposition temperature and the nitrogen pressure in the deposition chamber. We report that low optical absorption, textured polycrystalline AlN films can be produced by PLD on sapphire substrates at both low and high laser fluence using a background nitrogen pressure of 6.0 × 10− 2 Pa (4.5 × 10− 4 Torr) of 99.9% purity.
“This Is What I Do, and I Like It”

Fels reviews the classroom experiments presented in this issue and comments on the efficacy of experimental economics as a teaching tool.