cssi/SciSciGPT-SciSciNet huggingface dataset:
Theoretical studies of intersystem crossing effects in the O(3P, 1D)+H2 reaction

We have studied the influence of intersystem crossing on the reaction dynamics of the O+H2 reaction by performing trajectory surface hopping (TSH) calculations with accurate potential-energy surfaces and global spin–orbit coupling surfaces that we have generated using a four state model proposed by Hoffmann and Schatz. In the TSH calculations, we develop a new mixed representation that treats the reactant and product asymptotes in the adiabatic representation, and the singlet–triplet crossing region in the diabatic representation. This representation thus correctly describes O and OH fine structure-resolved cross sections, and it also treats intersystem crossing effects arising from the singlet–triplet crossing. Our calculations are based on the 1 3A′ and 1 3A″ states of Walch and Kuppermann, and the 1 1A′ state of Dobbyn and Knowles. The globally determined spin–orbit coupling matrix is derived from complete active space self-consistent field calculations using the two-electron Breit–Pauli Hamiltonian. O...
The v-Src SH3 Domain Facilitates a Cell Adhesion-independent Association with Focal Adhesion Kinase

Integrins facilitate cell attachment to the extracellular matrix, and these interactions generate cell survival, proliferation, and motility signals. Integrin signals are relayed in part by focal adhesion kinase (FAK) activation and the formation of a transient signaling complex initiated by Src homology 2 (SH2)-dependent binding of Src family protein-tyrosine kinases to the FAK Tyr-397 autophosphorylation site. Here we show that in viral Src (v-Src)-transformed NIH3T3 fibroblasts, an adhesion-independent FAK-Src signaling complex occurs. Co-expression studies in human 293T cells showed that v-Src could associate with and phosphorylate a Phe-397 FAK mutant at Tyr-925 promoting Grb2 binding to FAK in suspended cells. In vitro, glutathioneS-transferase fusion proteins of the v-Src SH3 but not c-Src SH3 domain bound to FAK in lysates of NIH3T3 fibroblasts. The v-Src SH3-binding sites were mapped to known proline-X-X-proline (PXXP) SH3-binding motifs in the FAK N- (residues 371–377) and C-terminal domains (residues 712–718 and 871–882) by in vitropull-down assays, and these sites are composed of a PXXPXXΦ (where Φ is a hydrophobic residue) v-Src SH3 binding consensus. Sequence comparisons show that residues in the RT loop region of the c-Src and v-Src SH3 domains differ. Substitution of c-Src RT loop residues (Arg-97 and Thr-98) for those found in the v-Src SH3 domain (Trp-97 and Ile-98) enhanced the binding of distinct NIH3T3 cellular proteins to a glutathione S-transferase fusion protein of the c-Src (Trp-97 + Ile-98) SH3 domain. FAK was identified as a c-Src (Trp-97 + Ile-98) SH3 domain target in fibroblasts, and co-expression studies in 293T cells showed that full-length c-Src (Trp-97 + Ile-98) could associate in vivo with Phe-397 FAK in an SH2-independent manner. These studies establish a functional role for the v-Src SH3 domain in stabilizing an adhesion-independent signaling complex with FAK.
On the limits of target recognition in the presence of atmospheric effects

The importance of Networked Automatic Target Recognition systems for surveillance applications is continuously increasing. Because of the requirement of a low cost and limited payload these networks are traditionally equipped with lightweight, low-cost sensors such as Electro Optical or Infrared sensors. The quality of imagery acquired by these sensors critically depends on the environmental conditions, type and characteristics of sensors, and absence of occluding or concealing objects. In the past a large number of efficient detection, tracking, and recognition algorithms have been designed to operate on imagery of good quality. However, detection and recognition limits under non-ideal environmental and/or sensor based distortions have not been carefully evaluated. This work describes a real image dataset formed by imaging 10 die cast models of military vehicles at different elevation and orientation angles. The dataset contains imagery acquired both indoors and outdoors. The indoors dataset is composed of clear and distorted images. The distortions include defocus blur, sided illumination, low contrast, shadows and occlusions. All images in this dataset, however, have a uniform blue background. The indoors dataset is applied to evaluate the degradations of recognition performance due to camera and illumination effects. The recognition method is based on Bessel K forms. The dataset collected outdoors includes real background and is much more complex to process. This dataset is used to evaluate performance of a fully automatic target recognition system that involves a Haar-based detector to select potential regions of interest within images; performs adjustment and fusion of detected regions; segments potential targets using a region based approach; identifies targets using Bessel K form-based encoding; and performs clutter rejection. The numerical results demonstrate that the complexity of the background and the presence of occlusions lead to substantial detection and recognition performance degradations.
Expression of the P/Q (Cav2.1) calcium channel in nodose sensory neurons and arterial baroreceptors.

Abstract The predominant calcium current in nodose sensory neurons, including the subpopulation of baroreceptor neurons, is the N-type channel, Cav2.2. It is also the primary calcium channel responsible for transmitter release at their presynaptic terminals in the nucleus of the solitary tract in the brainstem. The P/Q channel, Cav2.1, the other major calcium channel responsible for transmitter release at mammalian synapses, represents only 15–20% of total calcium current in the general population of sensory neurons and makes a minor contribution to transmitter release at the presynaptic terminal. In the present study we identified a subpopulation of the largest nodose neurons (capacitance > 50 pF) in which, surprisingly, Cav2.1 represents over 50% of the total calcium current, differing from the remainder of the population. Consistent with these electrophysiological data, anti-Cav2.1 antibody labeling was more membrane delimited in a subgroup of the large neurons in slices of nodose ganglia. Data reported in other synapses in the central nervous system assign different roles in synaptic information transfer to the P/Q-type versus N-type calcium channels. The study raises the possibility that the P/Q channel which has been associated with high fidelity transmission at other central synapses serves a similar function in this group of large myelinated sensory afferents, including arterial baroreceptors where a high frequency regular discharge pattern signals the pressure pulse. This contrasts to the irregular lower frequency discharge of the unmyelinated fibers that make up the majority of the sensory population and that utilize the N-type channel in synaptic transmission.
Multicultural education and social justice actions

Multicultural citizenship education courses worldwide show promise in their ability to influence attitudes and beliefs supportive of social justice. However, many of these courses assume behavior change results from these attitudes changes. Quantitative analyses of pretest and posttest questionnaire data compare the impact of these unique curricular strategies on students’ social action. The results reveal that these curricular strategies produce limited influence on social justice action. I suggest a social influence model of behavior change as a possibility for making multicultural education more effective at influencing behaviors for social justice action, thus reducing current and future social inequality.
Estimation of mixing rates in western Lake Ontario sediments by finite element analysis of210Pb profiles

A finite element model is used to generate theoretical excess210Pb concentration/depth profiles that are “best-fit approximations” to directly measured profiles at five locations in western Lake Ontario. The best-fit approximations are derived using a minimum error analysis technique. The results indicate that, while mixing is prevalent at all the study locations, its influence is severe at locations closer to the mouth of the Niagara River. The nonoccurrence of the implicit effects of sediment mixing in measured pollutant profiles at these locations is pointed out and it is postulated that the general assumptions of constant flux of excess210Pb and constant sedimentation rate in such models lead to unrealistic estimates of mixing.
Laser Scanning Lithography for Surface Micropatterning on Hydrogels

Techniques that control the spatial presentation of moieties such as cell adhesion peptides on surfaces are important for the advancement of tissue engineering, the elucidation of fundamental tissue structure-function relationships, and the formation of immobilized cell and protein arrays for biotechnology. Cell and protein patterns have previously been created using a range of methods, including photolithography 3] and soft lithographic approaches such as microcontact printing, microfluidic patterning, 6] and micromolding. 8] The patterned substrates have generally been modified silicon or glass, 10] whereas surface patterning of deformable, solvated substrates has not received a similar degree of attention. High fidelity patterning of deformable, solvated substrates is challenging, particularly since many commonly used patterning techniques cannot be readily applied. For example, microcontact printing is generally not applicable to such substrates due to lateral diffusion of the patterned molecule when the inked stamp comes into contact with the solvated substrate. Given the importance of deformable, solvated substrates, such as hydrogels, as scaffolds for soft tissue engineering applications, development of methods for direct, high fidelity surface patterning of these substrates is desirable.
Use of fractional dose-volume histograms to model risk of acute rectal toxicity among patients treated on RTOG 94-06.

Abstract Background and purpose For toxicities occurring during the course of radiotherapy, it is conceptually inaccurate to perform normal-tissue complication probability analyses using the complete dose–volume histogram. The goal of this study was to analyze acute rectal toxicity using a novel approach in which the fit of the Lyman–Kutcher–Burman (LKB) model is based on the fractional rectal dose–volume histogram (DVH). Materials and methods Grade ⩾2 acute rectal toxicity was analyzed in 509 patients treated on Radiation Therapy Oncology Group (RTOG) protocol 94-06. These patients had no field reductions or treatment-plan revisions during therapy, allowing the fractional rectal DVH to be estimated from the complete rectal DVH based on the total number of dose fractions delivered. Results The majority of patients experiencing Grade ⩾2 acute rectal toxicity did so before completion of radiotherapy (70/80=88%). Acute rectal toxicity depends on fractional mean rectal dose, with no significant improvement in the LKB model fit when the volume parameter differs from n =1. The incidence of toxicity was significantly lower for patients who received hormone therapy ( P =0.024). Conclusions Variations in fractional mean dose explain the differences in incidence of acute rectal toxicity, with no detectable effect seen here for differences in numbers of dose fractions delivered.
Domain walls in /sup 3/He-A in parallel-plate geometry. II

An earlier analysis of domain walls in superfluid /sup 3/He-A confined between two parallel plates with gap d (approx.xi/sub perpendicular/ the dipole coherence length) is extended into two directions: first, the effect of the nuclear dipole energy and the bending of the d vector are incorporated; second, the twist domain wall is also considered.
Double-layer effects on the electroreduction of lead(II) at mercury in dimethylformamide solutions

Abstract An analysis of the potential dependence of the apparent transfer coefficient and real activation enthalpy for a general two-step mechanism relating to an electrode reaction involving amalgam formation is presented. The significance of the analysis is discussed with respect to data for the reduction of Pb(II) at mercury in dimethylformamide solutions. Both the apparent transfer coefficient and real activation enthalpy for this reaction depend on the size of the tetraalkylammonium cation in solution and on the electrode potential. By analysing the double-layer effects and potential dependence of the kinetic parameters, it is concluded that the reaction is complex and involves ion transfer rather than electron transfer in the rate-determining steps.
Derivational Suffix Productivity for Students With and Without Language-Learning Disabilities

The effect of productivity (a correlate of suffix frequency) on students' derivational suffix use was investigated with students with and without language-learning disabilities (LLD). Sixty-nine elementary- to middle-school-age students participated in an elicitation task (in which they produced derived forms) and a forced-choice task (in which they selected derived forms) to label nonsense objects and events. In each task, students used highly productive suffixes to convey a given meaning. For example, students used the highly productive suffix er rather than the less productive suffix ant to convey an agentive meaning and used the more productive suffix let instead of the unproductive suffix kin to convey a diminutive meaning. Also, productivity appeared to guide accuracy of suffix use across meanings. For example, the agentive suffix er was produced with much higher accuracy than the less productive diminutive suffix let. In general, patterns of performance within and across meanings were the same for students with and without LLD. LLD students were less accurate in determining the meanings conveyed by derivational suffixes than typically achieving students matched for chronological age. However, their performance was similar to typically achieving students with comparable language skills.
Empire Stories: Imperious Objects and the Necessity of Fools

In this article, I examine and depict the attributes of empire narratives and discourse, arguing that these dominant narratives quietly shape and represent shared motivations of U.S. citizens in their active or tacit support of national hegemonic policies. Using an amended version of Winnicott's notion of transitional objects, I describe how these narratives may be understood as imperious objects. The psychological defenses of weak dissociation, rationalization, and denial are used to explain, in part, why many U.S. citizens overlook perspectives and questions that would challenge empire stories and ignore the destructive consequences of deeply and long held expansionist policies and actions. In addition, the psychosocial functions of the role of the fool, in conjunction with psychological defenses, help explain the public perpetuation of expansionist policies.
Evaluation of the mechanical quality factor under high power conditions in piezoelectric ceramics from electrical power

Abstract The main methods used to measure the mechanical quality factor in piezoelectric ceramics under high power resonance conditions are the electrical impedance method and the transient method. These methods are limited in their ability to provide relevant data from an application perspective because of the conditions under which the measurements must occur. In this research, a unique approach for characterizing the mechanical quality factor in piezoelectric materials has been developed. This method allows for the calculation of the quality factor from data at a single frequency, which is not possible with other methods. This technique has been applied to a hard PZT material for vibration conditions ranging from antiresonance to resonance at a vibration velocity of 100 mm/s RMS. Results from the quality factor measurement from impedance data and from the new method have a deviation of
Embryonic development of the larval body wall musculature of Drosophila melanogaster

The somatic, or body wall, muscles of the larva of Drosophila melanogaster are composed of an elaborate pattern of segmentally repeating fibers that form during embryogenesis. The primordia of these muscles progress from morphologically indistinct mesodermal cells to multinucleate syncytia with unique characteristics that include shape, size, location and attachment to the epidermis. Although relatively little is known about the development of the musculature and the mechanisms by which this elaborate pattern is achieved, recent progress has begun to reveal key players in this process.
How often is the von Bertalanffy-type length-at-age curve in fishes related to weight change artefacts interpreted as age rings in otoliths?

Abstract 1. 1. Convex, von Bertalanffy-type, length-at-age curves were similar in shape to length-at-weight curves in some fish species for which unvalidated techniques based on otolith check rings were used to age fish. 2. 2. Validated length-at-age curves from some fish species were not similar to length-at-weight curves. 3. 3. Otolith check rings in some species of fish may provide valuable information about the pattern of weight changes in individual fish, rather than their age.
Characteristic Motion Signatures Derived From the Theken eDisc Under Multi-Axial Loading

The motions and loads experienced by the human spine are complex and have been the subject of much study over the years. The emerging field of intervertebral disc arthroplasty offers products that must function within this complex loading environment over long periods of time. So called “first generation” intervertebral disc designs accomplish this through one or more articulating surfaces. Second generation artificial discs attempt to mimic the multi-axial disc motion and stiffness exhibited by the natural human disc. The eDisc not only provides this type of viscoelastic motion, but also provides the first capability to sense loads and motions to improve patient outcomes.Copyright © 2007 by ASME
Regional Differences of Cell Sizes in the Human Stratum Corneum. Part I

Individual non-damaged horny cells can be removed from the human stratum corneum by a modification of the corneocyte count technique. Nine sites from four men were sampled and 50 cells from each specimen measured with a filar micrometer eyepiece. The longest and shortest diameters in micra and the surface area, calculated as an ellipse in square micra, were determined. Individual horny cells are much larger than previously described in the literature. Small cells, 34 μ to 36 μ in diameter were found on forehead and hand, larger cells, 41 μ to 44μ are typical for thigh axilla. Highly significant statistical differences for multiple sites of the human body were found when t-tests and the analysis of variance were applied. The regional differences in cell sizes are discussed.
Predicting Institutional Adjustment with the Lifestyle Criminality Screening Form and Psychological Inventory of Criminal Thinking Styles

The Lifestyle Criminal Screening Form (LCSF) total score and the Psychological Inventory of Criminal Thinking Styles (PICTS) Reactive (R) scale both predicted subsequent aggressive disciplinary infractions in a group of 103 maximum security prison inmates but only the R scale successfully predicted total and nonaggressive disciplinary infractions in this group. Testing the incremental validity of these two measures it was determined that the LCSF failed to contribute significant unique variance to the prediction of disciplinary outcome when prior disciplinary record, age, and education were entered before the LCSF in a logistic regression analysis, but that the R scale successfully predicted total and aggressive disciplinary reports when entered into a logistic regression equation behind the LCSF, prior disciplinary record, and demographics (age, education).
Escherichia coli Diacylglycerol Kinase Is an Evolutionarily Optimized Membrane Enzyme and Catalyzes Direct Phosphoryl Transfer

In this contribution the kinetic mechanism and substrate specificity of Escherichia coli diacylglycerol kinase were examined. Steady state kinetic studies were carried out under mixed micellar conditions using a novel continuous coupled assay system. The kinetic data were consistent with a random equilibrium mechanism, implying that diacylglycerol kinase catalyzes direct phosphoryl transfer from MgATP to diacylglycerol. This was supported by failure to detect an enzyme-phosphate covalent intermediate and by the observation that the bisubstrate analog adenosine 5′-tetraphosphoryl-3-O-(1,2-dihexanoyl)-sn-glycerol inhibits the enzyme (K i ≪K m,DAG). While diacylglycerol kinase'sk cat/K m is modest compared with the efficiency of many water-soluble enzymes, the enzyme nevertheless appears to be an evolutionarily optimized biocatalyst in the sense that its chemical reaction rate approaches the substrate diffusion-controlled limit. The in vivo rate-limiting step of DAGK's reaction appears to be, in part, the transbilayer diffusion of diacylglycerol from the outer leaflet to the inner leaflet of the cytoplasmic membrane where DAGK's active site is located. DAGK was observed to maintain a high nucleotide substrate specificity, with most of this specificity being expressed in the form of reductions ink cat for ATP analogs.
Measurements of dynamic topography during synop utilizing a Geosat synthetic geoid

Dynamic topography estimates were obtained for the Gulf Stream region employing a previously derived synthetic geoid and Geosat radar altimeter measurements. Ascending tracks passed through the central and eastern arrays of the Synoptic Ocean Prediction experiment. By utilizing the geoid estimate instead of the mean altimetric signal, the axis position and velocity can be computed. A time series of the dynamic height profiles crossing the Gulf Stream and a table of the positions of the axis of the Stream along two tracks are given. Time series of the maximum velocity perpendicular to the ground track were computed for both arrays. It was found that there was a seasonal cycle in this time series with a maximum in November.
On the conceptual foundations of psychological measurement

Measurement has long been an important element of epistemology in the physical sciences and natural philosophy. More recently, the psychological sciences have developed a variety of techniques that purport to be instances of measurement as well. However, it is not clear how the understanding of measurement invoked in psychological science applications accords with the understanding of measurement found in other scientific disciplines. A sharper focus on conceptual clarity and coherence across the psychological and physical sciences has the potential to add a great deal to efforts to improve such practices. In this paper, we argue that it is possible to formulate a philosophically coherent account of how measurement works in both the physical and the human sciences.
Accelerated chromatography of amino acids associated with phenylketonuria, leucinosis (maple syrup urine disease), and other inborn errors of metabolism

Abstract Identification and quantitation of specific amino acids related to some metabolic disorders can be achieved in 1 hr or less. Plasma samples are analyzed on a 23 cm column of Beckman Custom Research Resin, PA-35, using either a pH 3.23, 0.35 N, or a pH 6.50, 0.35 N sodium citrate buffer at 90 ml/hr, with a 55°C column temperature. Phenylalanine can be analyzed in 21 min, tyrosine in 19 min, histidine in 28 min, methionine in 40 min, proline in 24 min, and the branched-chain amino acids in 60 min.
Health Care Disparity in the Care of the Vascular Patient

Peripheral vascular care continues to mature into a well-developed multidisciplinary subspecialty. Continued growth as a collaborative subspecialty will require delivering the highest quality medical care to all Americans. US census projections predict that greater than one half of all American citizens will identify themselves as ethnic or racial minorities by 2050. Evolving research has established significant health care disparity, or preventable differences in disease incidence and vascular procedure outcomes associated with socioeconomic, gender, language, geographic, racial, and ethnic variables. As a necessary step in the evolution of vascular care, practitioners, societies, and vascular departments should begin to adopt proven practices that enhance our ability to deliver equal care to an increasingly diverse American population.
Declarative representation of strategic control knowledge

Strategic (control) knowledge typically specifies how a target task is solved. Representing such knowledge declaratively remains a difficult and practical knowledge engineering challenge. The key to addressing this challenge rests on two observations. One, strategic knowledge comprises two finer types of knowledge: subgoaling knowledge used to construct the goal structure for each problem situation pertaining to a target task, and goal-sequencing knowledge used to choose which subgoal in this goal structure is to be pursued at any given moment. Second, when subgoaling knowledge is explicit and expressed in declarative ontological terms, it is possible to fully express goal-sequencing knowledge in the same declarative terms. Building on these observations, we achieve three things. First, we analyse several conventional knowledge-based applications whose subgoaling and goal-sequencing knowledge is implicit, showing that making their subgoaling knowledge explicit permits (re)representing their goal-sequencing knowledge declaratively. Among the applications analysed are MORE and NEOMYCIN. Second, upon studying the roles of goal-sequencing knowledge vis-a-vis subgoaling knowledge, we develop a declarative formalism for representing goal-sequencing knowledge. Finally, we discuss and illustrate key benefits from using our declarative formalism, including an enhanced ability to validate and reuse goal-sequencing knowledge.
CA4-02: When Additional Pounds Become a Health Threat: Childhood Obesity as a Risk for Hypertension?

Background/Aims Extreme obesity is an increasing concern in pediatric care but its association with pre-hypertension and hypertension are not clear. The objective of the present study is to assess the prevalence of different stages of pre-hypertension and hypertension in the pediatric population, to investigate potential disparities, and to evaluate the ideal BMI-for-age thresholds for pre-hypertension and hypertension.
Learning from others: an experimental test of Brownian motion uncertainty models:

Models of decision-making with outcome uncertainty are common in political science and related fields. Recent work in flagship journals has challenged canonical work by modeling outcome uncertainty...
Impact of Early and Consistent Occupational Therapy With Preterm Infants' Oral Feedings.

Purpose: This study was designed to assess the effectiveness of early occupational therapy intervention on preterm infant's ability to achieve full oral feedings and be discharged from the neonatal intensive care unit. Study design and methods: Forty-one preterm infants were randomized to receive occupational therapy intervention or sham intervention beginning at 30 weeks' gestational age. An oral stimulation and therapeutic feeding protocol was used for those infants in the experimental group. Sham intervention was used for the infants in the control group and included holding the infant without any provision of oral stimulation or therapeutic feedings. These interventions were provided three times a week for 10–15 minutes each. Outcome measures included: postmenstrual age at first successful feeding, postmenstrual age at full oral feedings, number of infants receiving occupational therapy consultations, postmenstrual age at discharge from neonatal intensive care unit, and total length of hospital stay. Results: No significant differences were found in the aggregate; however, significant differences were found in the subgroup of less then 29 weeks' gestational age. Extremely preterm infants receiving early occupational therapy achieved full oral feedings on average 2.3 weeks earlier than their control counterparts. Conclusion: Early limited occupational therapy intervention may accelerate time to full oral feeding in extremely preterm infants.
Effects of ventromedial hypothalamic lesions on rat ethanol intake

Abstract The consumption of food, water and ethanol solutions, in free choice condition, was studied in 9 rats with electrolitic lesion of ventromedial hypothalamus, before and after the operation and compared with 2 controls submitted to sham operation. Changes in body weight were studied between 20 and 30 days after the operation. In all the experimental rats there was an increase in food, water consumption and body weight while ethanol intake decreased significantly.
Human smooth muscle cell cultures of the stomach morphologic and biochemical studies

Smooth muscle cell cultures were prepared from stomach explants obtained surgically from 10 patients with duodenal ulcer. The cultured cells grew in either overlapping layers in “hills and valleys” or in parallel arrays. The ultrastructure studies showed plasmalemmal vesicles, bundles of myofilaments associated with dense bodies, and gap junctions. The synthesis of contractile proteins illustrated the preponderance of actin on myosin and tropomyosin. The synthesis of contractile proteins in stomach smooth muscle cell cultures is significantly higher than in skin fibroblast cultures, i.e. 20 x higher for myosin, 10 x higher for actin, and 30 x higher for tropomyosin.
A juvenile ankylosaur referable to the genus Euoplocephalus (Reptilia, Ornithischia)

ABSTRACT A specimen of a juvenile ankylosaur from the Upper Cretaceous Horseshoe Canyon Formation (Red Deer River, Alberta, Canada) includes a nearly complete pes, the first reported for the genus Euoplocephalus. Differences between juvenile and adult ankylosaurs are qualitatively similar to differences reported for juvenile and adult stegosaurs.
Why don't we know whether care is safe?

Reliable data are essential to ensuring that health care is delivered safely and appropriately. Yet the availability of reliable data on safety remains surprisingly poor, as does our knowledge of w...
VITAL STAINING OF THE CONNECTIVE TISSUES.

Trypan blue injected intravenously is bound almost at once by the intercellular connective tissue elements all over the body,—by collagen, reticulin, and elastic fibers. This union of dye and tissue elements is the factor responsible for the early macroscopic blue color and is antecedent to cellular colloidopexic action. Different examples of connective tissue differ among themselves in their ability to hold the dye. Diffuse staining of elastic fibers noted by previous observers is merely a special case of the general affinity of connective tissue for the dye. The evidence suggests that the histiocytes are cells specialized to segregate noxae that become diffusely bound to the intercellular connective tissue matrix.
Endoneurial potassium is increased and enhances spontaneous activity in regenerating mammalian nerve fibers—implications for neuropathic positive symptoms

The endoneurial fluid potassium [K+]e has potent effects on membrane potential and excitability but direct measurements have not been reported. The [K+]e was measured with K+ ion-sensitive microelectrodes in normal, demyelinated, and regenerating rat peripheral nerve fibers. The mean value in normal nerve was 3.7 mM. The [K+]e was consistently elevated in regenerating nerves and infrequently elevated in demyelinated nerves. The time course of [K+]e was studied in the left tibial nerve of 22 rats 2 days to 3 months in the extended crush model. The [K+]e was increased and peaked in the first 2 weeks, with a progressive decline toward control values after that. Single fiber recordings were made from the tibial division of the sciatic nerve in 13 animals. The mean number of single fibers studied per rat was 55.5 (SD 24.6). Spontaneous activity (SA) was present in all regenerating nerves and was maximal in the first 2-4 weeks. Endoneurial K+ was further increased by intraarterial injection of potassium into the saphenous artery. Spontaneous activity was enhanced when [K+]e began to rise; there were further superimposed bursts of SA with the administration of additional boluses. These findings suggest that [K+]e increase is a factor in enhancing SA in damaged nerve fibers.
Climate‐induced forest dieback as an emergent global phenomenon

An organized oral session at the annual meeting of the Ecological Society of America in San Jose, Calif., posed this question: Is climate-induced drought stress triggering increasing rates and unusual patterns of forest die-off at a global scale? Twenty-nine researchers representing five continents reported on patterns, mechanisms, and projections of forest mortality. Observations include widespread forest dieback or reductions in tree cover and biodiversity in response to drought and warmer temperatures in the African Sahel (Patrick Gonzalez, The Nature Conservancy), Mediterranean and alpine Europe (Jorge Castro, Universidad de Granada), and Argentinean Patagonia (Thomas Kitzberger, Universidad Nacional del Comahue). In contrast, although much Eucalyptus mortality has resulted from recent droughts in Australia, warming trends have been less pronounced in the Southern Hemisphere and it is unclear if contemporary climate-induced tree mortality differs from previous historical drought impacts (Rod Fensham, Queensland Herbarium).
The Acquisition of Addition and Subtraction Concepts in Grades One through Three.

Children's solutions to simple addition and subtraction word problems were studied in a 3-year longitudinal study that followed 88 children from Grades 1 through 3. The children were able to solve the problems using a variety of modeling and counting strategies even before they received formal instruction in arithmetic. The invented strategies continued to be used after several years of formal instruction. Four levels of problemsolving ability were found. At the first level, children could solve problems only by externally modeling them with physical objects. Modeling strategies were gradually replaced with more sophisticated counting strategies. The results of the study are at variance with important aspects of models of children's performance proposed by Briars and Larkin and by Riley, Greeno, and Heller.
Learning as a function of meaning levels with American and German SS.

An American and a German sample of Ss were required to learn to a criterion of 2 successive trials without error a list of 10 ordinary words and a list of 10 0% association value syllables. Both groups first learned unknown nonsense syllables, then syllables with which they were familiarized, and then syllables which were made meaningful in a “synonym-definition” sense (e.g., TOV means grass). The results indicated that meaning operationally employed in a “synonym-definition” sense was a significant aid when learning syllables in order was not required; performance equalled that with words. In addition, protocols were obtained from all Ss in all phases, and these data made possible a clearer interpretation of the performance data.
Mapping of magnetospheric boundaries

Abstract Observations of ionospheric processes and signatures can provide an very powerful tool for a better understanding of magnetospheric dynamics because they provide two-dimensional images of magnetospheric processes. The magnetospheric origin of ionospheric signatures (and vice versa) can be determined by using a mapping along a model magnetic field for a particular level of magnetospheric activity. Such studies have provided much insight into the structure of magnetospheric boundaries. They require, however, much care for time dependent processes which are characteristic for periods of auroral and magnetospheric activity. A mapping along a model magnetic field requires that information is indeed transported along field lines, that the actual field is sufficiently well represented by the model field, and that the information is not modified by physical process in the inner magnetosphere. Another problem is the timing of processes respectively the speed with which information is exchanged. A beam of field aligned electrons which is generated at the magnetospheric boundary will reach the ionosphere significantly earlier than an Alfven wave which is generated at the same time and location. These aspects of the mapping of magnetospheric boundaries will be addressed in more detail.
Induction of heat-shock proteins by glutamine. The 'feeding effect'.

Subconfluent, log-phase Chinese hamster ovary cells induced the major heat-shock proteins (hsp) when cells were refed, 40 hours after seeding. This method of inducing heat-shock proteins was also obtained by refeeding with fresh serum-free media, but not with media with a long shelf life or with media prepared without glutamine. It was observed that addition of glutamine alone to cultures at 40 hours post-seeding induced heat-shock proteins. Addition of ammonium chloride, however, had no discernible effect on heat-shock protein synthesis. Northern blot analysis indicated that this phenomenon reflected an increase in the levels of message for the constitutive/inducible member of the hsp 70 family, but not the non-constitutive member. To determine the effect of this induction on heat sensitivity, unfed and ‘heat-shock-induced’ refed cultures were heated at 45°C. No significant difference in cell survival was observed. Therefore glutamine is the necessary ingredient required for the induction of heat-shock proteins and this method of inducing heat-shock proteins does not alter heat sensitivity.
Improving oral hygiene by increasing the width of keratinized tissue around dental implants using free gingival graft: A case report and literature review

The need for keratinized tissue around endosseous implants is a controversial topic. The rationale for augmenting the keratinized tissue includes making plaque control more effective, dissipating muscular and frenal pull and possibly preventing further recession. In this case report, free gingival graft was used to overcome the patient's discomfort. The increase of keratinized tissue improved the condition of the peri-implant marginal tissue. This procedure appears to show benefits for oral hygiene, even though certain amount of shrinkage is seen both horizontally and vertically.
Effect of thermal spin-wave fluctuations on optical guided waves propagating in a magnetic film.

Effet des fluctuations de la diffusion lumineuse issues de l'excitation thermique des ondes de spins sur les ondes optiques guidees se propageant dans un film magnetique. Ces ondes de spin thermiques induisent la conversion des modes dans les ondes optiques guidees qui se manifeste comme le bruit optique pendant la rotation de Faraday. Le theoreme de l'equipartition relie ce bruit optique a celui rencontre dans la conjugaison des phases dans un milieu a effet Kerr optique. La theorie affirme qu'un canal pour les non-linearites optiques du troisieme ordre des ondes optiques guidees dans un film magnetique est cree par l'intermediaire de ces ondes de spins thermiques; et on derive une expression pour leur contribution a ce coefficient d'effet Kerr optique non lineaire
A mathematical model for analysis of pharmacologically induced changes in the kinetics of cardiac muscle

A mathematical model of the isometric contraction of cardiac muscle is developed and utilized to characterize the inotropic and lusitropic effects of cardioactive compounds in isolated guinea pig left atria. In contrast to metrics that are based on minima and maxima of an isometric twitch and its derivative function, the entire time course of the twitch is used to quantify the kinetics of the contraction-relaxation cycle. The model relates observed tension to a time-dependent activation function that describes generation of internal force and a coupling function that determines mechanical response to the activation function. The model is structured so that it is suitable for nonlinear curve fitting to observed data. Results obtained using the model for fitting experimental data from tissues treated with different classes of cardioactive compounds agree with more qualitative results presented by other authors. Experiments using the model to fit data over an extended (90 min) time course revealed differences in the kinetic profiles of milrinone and forskolin. Computer simulations that demonstrate the effect of each model parameter on twitch kinetics are presented, and the relationships between the model and other theoretical and empirical models of cardiac muscle are discussed. The mathematical model is useful to enable a more quantitative understanding of the kinetics of cardiac muscle contraction and relaxation and identify compounds that may be selective for inotropic or lusitropic effects.
Bilateral actions of the reticulospinal tract on arm and shoulder muscles in the monkey: stimulus triggered averaging

The motor output of the pontomedullary reticular formation (PMRF) was investigated to determine the reticulospinal system's capacity for bilateral control of the upper limbs. Stimulus triggered electromyographic averages (StimulusTA) were constructed from muscles of both upper limbs while two awake monkeys (Macaca fascicularis) performed a reaching task using either arm. Extensor and flexor muscles were studied at the wrist, elbow, and shoulder; muscles acting on the scapula were also studied. Post-stimulus effects (PStEs) resulted from 435 (81%) of 535 sites tested. Of 1611 PStEs analyzed, 58% were post-stimulus suppression (PStS), and 42% were post-stimulus facilitation (PStF). Onset latency was earlier for PStF than PStS, duration was longer for PStS, and amplitude was larger for PStF. Ipsilateral and contralateral PStEs were equally prevalent; bilateral responses were typical. In the ipsilateral forelimb and shoulder, the prevalent pattern was flexor PStF and extensor PStS; the opposite pattern was prevalent contralaterally. Sites producing strong ipsilateral upper trapezius PStF were concentrated in a region caudal and ventral to abducens. The majority of muscles studied had no clear somatotopic organization. Overall, the results indicate the monkey PMRF has the capacity to support bilateral coordination of limb movements using reciprocal actions within a limb and between sides.
How much is an elephant worth

The Value of Life: Biological Diversity and Human Society. By Stephen R. Kellert. Island/Shearwater: 1996. Pp. 263. $24.95. The Sixth Extinction. By Richard Leakey and Roger Lewin. Doubleday/Weidenfeld and Nicolson: 1995. Pp. 271. $24.95, £18.99. Conservation and Biodiversity. By Andrew P. Dobson. W. H. Freeman/Scientific American Library: 1996. Pp. 264. $32.95, £19.95.
Vagally-regulated gastric motor activity: evidence for kainate and NMDA receptor mediation.

Abstract Blockade of GABAA receptors in the dorsal vagal complex produces marked gastric motor excitation. This effect is abolished by a prior microinjection of a non-selective excitatory amino acid receptor antagonist. Here we present functional evidence for kainate and NMDA receptor-mediated gastric excitation in the dorsal vagal complex. Microinjections into the dorsal vagal complex were performed in α-chloralose-anesthetized rats using multi-barrelled glass micropipettes while recording intragastric pressure and motility. Kainic acid (30 and 100 pmol in 30 nl) and NMDA (100 and 300 pmol) produced dose-related increases in intragastric pressure and motility. The gastric responses to kainate (30 pmol) and NMDA were selectively abolished by prior microinjection 6,7-dinitroquinoxaline-2,3-dione (600 pmol, 60 nl) and dl -2-amino-5-phosphanopentanoic acid (2 nmol), respectively. Atropine (1 mg/kg, i.v.) pretreatment blocked kainate-, NMDA- and l -glutamate-induced gastric excitation. Thus, both kainate- and NMDA-receptors in the dorsal vagal complex can independently cause vagally-mediated gastric motor excitation.
Determination of heats of volatilization for polymers by differential scanning calorimetry

In the design of thermal degradation processes for polymers, the energy to degrade or volatilize the materials soften must be known. The heats of volatilization for six polymers were measured by differential scanning calorimetry (DSC), where the area under the degradation endotherm peak was shown to be directly proportional to the heat of volatilization. Values measured for poly(methyl methacrylate), which yields monomer quantitatively in the temperature range investigated, agree well with theoretically predicted values. Reproducibility of the method is shown by an average standard deviation of ±10% for the six polymers investigated. Caution must be used when applying data obtained by this method to thermal conditions widely differing from those employed in the DSC.
Evolution of aircraft‐generated volatile particles in the far wake regime: Potential contributions to ambient CCN/IN

We apply a detailed aerosol microphysics model to study the evolution of aerosols in the far wake of an aircraft plume. Constrained by in-situ measurements, our simulations reveal that the largest volatile particles—those most likely to contribute to the background abundance of condensation nuclei—are dominated by ion-mode aerosols formed on chemiions. By tracking the evolution of the aircraft-generated particles from the near wake to the far wake, we estimate the properties of the aircraft particles that are effectively injected into the upper troposphere. The entrainment of ambient vapors and aerosols into the aging plume is taken into account, which significantly affects the outcome. The model calculations reveal that a substantial number of the larger ion-mode volatile particles may survive long enough to act as potential cloud nuclei, thus perturbing the background CCN population. This perturbation is significant during the winter season, and in other locales with low background aerosol concentrations, but is likely to be negligible during the summer season or at locations with heavy aerosol loading. The implications and uncertainties of the results are discussed.
Sound‐producing sources as objects of perception: Rate normalization and nonspeech perception

In a variety of experiments and paradigms, researchers have attempted to determine whether or not speech perception is specialized by comparing perception of speech syllables to perception of nonspeech analogs. While nonspeech analogs appear optimal as comparisons to speech because they are acoustically similar without being recognized as speechlike, it is argued that the comparison they offer is confounded and uninterpretable. Two experiments are designed to show that, in auditory perception generally where acoustic signals are causal consequences of mechanical events, perceptual experiences are of the mechanical events themselves, not of the acoustic signal. This has two consequences. One is that there is a confounding in comparisons of speech with sine wave analogs that, whereas the one perceived as speech also has a definite causal source, the other, perceived as nonspeech, has an indeterminate or ambiguous source. A second is that response patterns in classification tasks such as those used in the literature comparing speech to nonspeech will reflect properties of the perceived sound‐producing event; they will not provide a clear window on auditory system processes used to recover event properties. Experiment 3 is designed to show that perception of many acoustic‐signal‐producing events can appear to be special by the logic of speech–sine wave comparisons—even events that cannot plausibly be supposed to involve a specialization.