cssi/SciSciGPT-SciSciNet huggingface dataset:
Numerical Biaxial Characterization for Concrete

A biaxial characterization for concrete as a nonlinear inelastic material is developed from the most complete experimental biaxial information available. The representation of concrete behavior used bears many similarities to cumulative damage concepts. For computational ease, the continuous accumulation of damage is replaced by four damage regions in which constant parameters are assumed to define the behavior. The initial characterization is developed in stress space and then transformed to strain space to avoid nonuniqueness of representation. The method by which the representation is used to predict an incremental stress-strain law for an arbitrary change in strain state is described to demonstrate its suitability for finite element analysis. To derive such constitutive relations in biaxial form requires only a multilinear approximation of the uniaxial compression stress-strain behavior, the biaxial failure stress (or strain) envelope, and values of Poisson's ratio. The representation is compared to available biaxial test information and shown to describe the essential characteristics of biaxial response.
Cones and Hypercones

This chapter builds on the preceding chapter, and like its predecessor consists of two well-defined parts—a study of cones followed by a parallel study of their generalization, hypercones. A cone is defined to be a union of a family of rays that have a common endpoint. Cones which are convex, and of these, especially those which are “pointed”, are of most importance. The problem of how convex cones are generated by their rays receives a major share of our attention. Naturally the case of the polyhedral cone—a convex cone generated by a finite family of rays—is considered. The notion of an extreme ray of a convex cone, as an analogue of an extreme point of an arbitrary convex set, is clarified and examined closely. Then the study of cones concludes with the determination of conditions for a polyhedral cone to be generated by its extreme rays.
Failure-driven learning as model-based self-redesign

Learning is a competence fundamental to intelligence. Intelligent agents who solve problems in a realistic environment need to learn in order to improve their performance in terms of the quality of the solutions they produce, the efficiency of their problem-solving process, and the class of problems they can solve. Failures in problem solving signify the need and the opportunity to learn. One way in which an agent may effectively use its failed problem-solving experiences to learn, is by reflection upon its own problem-solving process. To that end, the agent needs an explicit model of its own problem-solving behavior. This work adopts a design stance towards reflective, failure-driven, learning. This stance gives rise to a specific computational model which is based on three key ideas: (i) agents can be viewed as abstract devices; (ii) their problem solving can be understood in terms of structure-behavior-function (SBF) models; finally, (iii) failure-driven learning can be viewed as a model-based redesign process, in which the agent uses its comprehension of its own problem solving to repair itself. When the agent fails, it uses feedback from the world, and the trace of the failed process, to search through this model and identify the cause(s) of its failure. Then, it proceeds to repair its problem solving, in order not to fail again for the same reason. This theory of reflective learning has been implemented in a fully operational system, A scUTOGNOSTIC. A scUTOGNOSTIC is like a "shell" in that it provides the SBF language for specifying a problem solver, and the inference mechanism for monitoring this problem-solver's reasoning, assigning blame when it fails, and repairing it appropriately. Three different systems have been modeled in A scUTOGNOSTIC'S SBF language: R scOUTER, a path planning system, K scRITIK2, a design system, and an autonomous, reactive agent implemented in the AuRA architecture. Extensive experiments conducted with A scUTOGNOSTIC demonstrate the generality and the effectiveness of its learning process.
Magnetism in ordered and amorphous Y Co 3 and Y Fe 3

Local magnetic moments on cobalt atoms in ordered and amorphous Y${\mathrm{Co}}_{3}$ differ dramatically, whereas those on iron atoms in ordered and amorphous Y${\mathrm{Fe}}_{3}$ do not. Our energy-band calculations for these systems show that Y${\mathrm{Co}}_{3}$ in the ${\mathrm{Cu}}_{3}$Au model structure has an equilibrium lattice constant which lies within a few percent of a volume-induced magnetic instability, whereas the equilibrium lattice constant for Y${\mathrm{Fe}}_{3}$ lies in a region of stable magnetism. The calculations suggest that the difference in the magnetic moment of ordered and amorphous Y${\mathrm{Co}}_{3}$ is a consequence of this magnetic instability and a difference in the atomic densities of the two forms of this material. This density difference is sufficient to lower the moment for ordered Y${\mathrm{Co}}_{3}$ but not for ordered Y${\mathrm{Fe}}_{3}$.
On the Clique-Width of Graphs in Hereditary Classes

The paper presents several results that can be helpful for deciding whether the clique-width of graphs in a certain class is bounded or not, and applies these results to a number of particular graph classes.
In search of the chains that hold Brazil back

This paper performs a Growth Diagnostic for Brazil. It shows that many aspects of the Brazilian economy have been improving, including the macro picture, educational progress and the external front. Moreover, Brazil has many productive possibilities and high-return investments. Yet growth is hampered because of a relatively old-fashioned problem that has been solved in many other countries in the region: creating a financially viable state that does not over-borrow, over-tax or under-invest. We show that domestic saving is the binding constraint on growth and that it has a fiscal cause. Although things are trending in the right direction, the challenge is to exploit the current good times to create the fiscal basis for a sustained growth acceleration.
SU-EE-A1-04: Integrated Complementary IMRT Combined with Image-Guided HDR Brachytherapy for Cancers of the Uterine Cervix

Purpose: Conventional HDR (CHDR) brachytherapy for cervical cancers often fails to cover the entire gross tumor volume (GTV). CT/MRI‐based 3‐D planning allows optimization of dwell times for improved target coverage, but often at the cost of substantially higher doses to organs at risk (OARs). In the present study, we integrate image‐guided HDR brachytherapy with concomitant complementary IMRT to boost target coverage and maintain low doses to OARs. Method and Materials:Treatment planningCT and MRIimages of 6 patients were acquired with CT/MRI‐compatible carbon‐fiber applicator. HDR plans were obtained by modifying CHDR plans to keep bladder and rectum dose below 80%. Based on these HDR plans, IMRT plans were subsequently optimized to complement the dose coverage of GTV with 3‐mm margin (GTV+) and the uterus. To prevent anatomical deformation, IMRT plans were to be delivered immediately following image‐guided HDR treatment with applicator in place. V95% (Target volume receiving 95% prescription dose) and D2 (minimum dose in 2.0‐cm3 OAR volume receiving the highest dose) were used to compare IMRT‐HDR technique with CHDR and HDR optimized for target coverage (OHDR). Results: The MRT‐HDR technique substantially improved target coverage while maintaining bladder and rectum doses at acceptable low level. For the six patients, V95% for GTV+ and the uterus improved from the average of 56.8% and 51.4% in CHDR to 92.5% and 95.3% in IMRT‐HDR, respectively. Average D2doses to bladder and rectum were 88.7% and 65.2% for CHDR and 72.4% and 71.4% for IMRT‐HDR. In contrast, OHDR improved target coverage, but D2doses to bladder (>119%) and rectum (87.3% to > 200%) were unacceptably high. Conclusion: Integrated complementary IMRT combined with image‐guide HDR significantly improves dose coverage to the targets while maintaining low doses to OARs. It is dosimetrically and logistically feasible to clinically implement this technique for potentially improved outcome.
DUAL‐RESOURCE PARALLEL QUEUES WITH SERVER TRANSFER AND INFORMATION ACCESS DELAYS*

Dual-resource constrained queuing systems contain fewer servers than service facilities. This study uses computer simulation to evaluate several server assignment procedures in a dual-resource system. A field study serves as the basis for developing a model with two service facilities in parallel, a single server, and deterministic information access and transfer delays that can be applied to job shops, computer operating systems, and elevators. Several findings, useful in server assignment decision making, resulted from the study. If first-come, first-served sequencing is used, delaying server assignment at a facility until all jobs are completed reduces both the mean and the variance of job flow time. If shortest-process-time-first sequencing is used, an assignment rule is tested that delays a server at a facility until a sufficiently short job is estimated to have arrived elsewhere. This rule performs best overall in terms of both the mean and variance of flow time. Methods to implement this decision rule easily are discussed.
An electrostatic interaction at the tetrahelix bundle promotes phosphorylation-dependent cystic fibrosis transmembrane conductance regulator (CFTR) channel opening

The CFTR channel is an essential mediator of electrolyte transport across epithelial tissues. CFTR opening is promoted by ATP binding and dimerization of its two nucleotide binding domains (NBDs). Phosphorylation of its R domain (e.g. by PKA) is also required for channel activity. The CFTR structure is unsolved but homology models of the CFTR closed and open states have been produced based on the crystal structures of evolutionarily related ABC transporters. These models predict the formation of a tetrahelix bundle of intracellular loops (ICLs) during channel opening. Here we provide evidence that residues E267 in ICL2 and K1060 in ICL4 electrostatically interact at the interface of this predicted bundle to promote CFTR opening. Mutations or a thiol modifier that introduced like charges at these two positions substantially inhibited ATP-dependent channel opening. ATP-dependent activity was rescued by introducing a second site gain of function (GOF) mutation that was previously shown to promote ATP-dependent and ATP-independent opening (K978C). Conversely, the ATP-independent activity of the K978C GOF mutant was inhibited by charge- reversal mutations at positions 267 or 1060 either in the presence or absence of NBD2. The latter result indicates that this electrostatic interaction also promotes unliganded channel opening in the absence of ATP binding and NBD dimerization. Charge-reversal mutations at either position markedly reduced the PKA sensitivity of channel activation implying strong allosteric coupling between bundle formation and R domain phosphorylation. These findings support important roles of the tetrahelix bundle and the E267-K1060 electrostatic interaction in phosphorylation-dependent CFTR gating.
The man who killed Warrington Dawson.

On March 12, 1889, at about 4:00 p.m., the editor of the Charleston, South Carolina, News and Courier--Francis Warrington Dawson--was shot to death by Thomas Ballard McDow, M.D., a successful Charleston physician, in Dr. McDow's office. The investigation of the crime and the trial and acquittal of McDow have not been subjected to critical scrutiny in this century. This article offers an analysis of character and motivation of the principals, an examination of some of the evidence, a view of the prosecution and defense, and some conclusions based on these elements. Language: en
Using Activity-Oriented Design Methods to Study Collaborative Knowledge-Building in e-Learning Courses within Higher Education

Trends in higher education have contributed to the need for more coordination and collaboration among different constituencies involved in instructional design and delivery. As researchers and educational technologists working in a large public research university, our research focuses on understanding the interactions among various stakeholder groups involved in e-Learning courses. In this paper we provide an interpretation of how Activity-Oriented Design Methods (AODM) based on Activity Theory can be used to develop a more comprehensive understanding of collaborative knowledge building practices among course design teams and their students. We also discuss how these methods can inform instructional design and development within distance education programs. In the absence of universally accepted methods for applying activity theoretical perspectives, these methods provide an analytic scheme for identifying the essential elements of an activity and for examining their interrelationships or contradictions, which are essential to improving the activity overall. The procedures described here have been used in a series of e-Learning case studies at our institution. We draw from one case to illustrate our interpretation of Activity-Oriented Design Methods. The themes discussed in this paper have implications for a broad audience of educational researchers, technologists, instructional systems designers, faculty, course assistants, and administrators concerned with examining and advancing collaboration among different groups in developing e-Learning.
RENAL SEGMENTAL “HYPOPLASIA” (ASK-UPMARK): PATHOLOGIC ASPECTS

Segmental “hypoplasia” of the kidney is a form of severe renal atrophy commonly associated with vesicoureteric reflux (VUR). The scarred segments contain atrophic tubules and hyperplastic blood vessels; glomeruli are often absent or sparse. These lesions have been identified in 21 patients (12F, 9M), 6-27 yr: 13 (62%) hypertensive (HT) and 8 normotensive (NT); 13 with prior urinary tract infection; 18/19 (95%) with radiographic VUR; 8 (38%) with impaired renal function (GFR <40 ml/min/1.73 m2); none with severe proteinuria. Renal atrophy commonly progressed after surgical repair of VUR, even in absence of infection. Lesions were bilateral in 5 HT patients and 2 others had unilateral agenesis; bilateral in only 1 NT patient. HT responded to nephrectomy in all patients. Histologic examination of the scars showed no differences between HT and NT patients in numbers of sclerotic glomeruli or in severity of interstitial fibrosis, arteriolar sclerosis, and inflammatory cell infiltration. Examination of cortical tissue adjacent to scars showed HT patients to have more severe tubular atrophy and vascular change, possibly as the result of HT. Thioflavin-T staining showed the sclerotic glomeruli and hypertrophic arterioles to contain more JGA granules in the scars of HT than of NT patients. Segmental “hypoplasia” appears to be an acquired abnormality, although its association with renal dysplasia in two specimens indicates an occasional origin during intrauterine life.
Cellular level brain imaging in behaving mammals: an engineering approach.

Fluorescence imaging offers expanding capabilities for recording neural dynamics in behaving mammals, including the means to monitor hundreds of cells targeted by genetic type or connectivity, track cells over weeks, densely sample neurons within local microcircuits, study cells too inactive to isolate in extracellular electrical recordings, and visualize activity in dendrites, axons, or dendritic spines. We discuss recent progress and future directions for imaging in behaving mammals from a systems engineering perspective, which seeks holistic consideration of fluorescent indicators, optical instrumentation, and computational analyses. Today, genetically encoded indicators of neural Ca 2+ dynamics are widely used, and those of trans-membrane voltage are rapidly improving. Two complementary imaging paradigms involve conventional microscopes for studying head-restrained animals and head-mounted miniature microscopes for imaging in freely behaving animals. Overall, the field has attained sufficient sophistication that increased cooperation between those designing new indicators, light sources, microscopes, and computational analyses would greatly benefit future progress.
Chemical reactions in the gas phase and in condensed matter: From wavefunctions to density operators

This contribution generalizes the treatment of chemical reactions in the gas phase based on the reaction channel decomposition of the wavefunction, by introducing a similar channel decomposition of the statistical density operator valid also for condensed phases such as liquid solutions and solid surfaces. Coupled equations for the channel components of the density operator are derived and a brief presentation is given of their partial Wigner transform, which leads to a general treatment for coupling quantum and classical variables. This provides a general approach for reactions involving electronically excited states in many-atom systems. It is pointed out that reactions involving coupled quantal and classical variables can be correctly described provided (a) initial conditions for trajectories are generated from quantal distributions and (b) the bundle of trajectories for the whole initial classical phase space is propagated coupled to the quantal elements of the density matrix and used in the calculation of reaction flux averages. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Constraints on the Magnetic Field Geometry in Prominences

This paper discusses constraints on the magnetic field geometry of solar prominences derived from one-dimensional modeling and analytic theory of the formation and support of cool coronal condensations. In earlier numerical studies we identified a mechanism—thermal nonequilibrium—by which cool condensations can form on field lines heated at their footpoints. We also identified a broad range of field line shapes that can support condensations with the observed sizes and lifetimes: shallowly dipped to moderately arched field lines longer than several times the heating scale. Here we demonstrate that condensations formed on deeply dipped field lines, as would occur in all but the near-axial regions of twisted flux ropes, behave significantly differently than those on shallowly dipped field lines. Our modeling results yield a crucial observational test capable of discriminating between two competing scenarios for prominence magnetic field structure: the flux rope and sheared-arcade models.
Developmental changes in children's use of semantic information in recall ☆

Abstract Third and seventh graders (age 9 and 13 years) were randomly assigned to three instructional groups and engaged in a sort/recall task. The instructions emphasized either (a) recall of the items, (b) meaningful organization of the items, or (c) meaningful organization and recall of the items. Regardless of instruction, seventh graders sorted 20 unrelated items into semantically-based groupings and exhibited elevated levels of recall. Third graders instructed to group items to facilitate recall formed seemingly random groupings and recalled significantly fewer items than third graders instructed to make semantically-based groupings, even when some of these latter subjects were unaware of a subsequent recall trial. The results indicated that young children are capable of adult-like organizational strategies but are unaware of their relevance to recall performance or conditions under which organization might be an appropriate strategy.
Increased plasma interleukin 6 concentrations and exaggerated adipose tissue interleukin 6 content in severely obese patients after operative trauma.

Background The cytokine response to operative trauma may be altered in obesity. Thus, we monitored changes in systemic and adipose tissue content of interleukin 6 (IL-6) and in insulin resistance in nonobese versus severely obese patients before and immediately after abdominal operations. Methods At the beginning and the end of operation, blood samples and biopsies consisting of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were collected from 13 nonobese and 33 severely obese patients. Systemic concentrations of glucose, insulin, and IL-6, as well as adipose tissue content of IL-6, were determined. Results Plasma IL-6 concentration and adipose tissue content of IL-6 increased, compared with baseline in patients after operation (plasma, 13- and 5.7-fold; VAT, 270- and 210-fold; SAT, 79- and 8.2-fold in severely obese vs nonobese patients, respectively). The increase in IL-6 in plasma and in both VAT and SAT was exaggerated in severely obese patients, compared with nonobese patients. Increases after operation in plasma IL-6 concentrations were correlated positively to the corresponding increases in both SAT and VAT IL-6 content (r = 0.57 and 0.66, respectively). Also, we found a positive correlation between the worsening of insulin resistance and increases in both plasma and SAT IL-6 concentrations (r = 0.40 and 0.51, respectively). Conclusions Circulating IL-6 concentrations both at baseline and after operation are related strongly to abdominal adipose tissue content of content of IL-6 and are exaggerated in severely obese persons. After operation, worsening of insulin resistance is associated with increasing plasma and adipose tissue content of IL-6.
On some relations for the rank moduli 9 and 12

Abstract In this paper we prove some identities, conjectured by Lewis, concerning the rank moduli 9 and 12, which are similar to Dyson's identities for the rank moduli 5 and 7 which give a combinatorial explanation to Ramanujan's partition congruences. For this we use multisection of series and some identities for the third and sixth order Mock theta functions, in such a way that all the identities for a given modulus reduce to a single theta identity.
Evaluation of a Computational Model of Situational Awareness

Although the use of the psychological construct of situational awareness (SA) assists researchers in creating a flight environment that is safer and more predictable, its true potential remains untapped until a valid means of predicting SA a priori becomes available. Previous work proposed a computational model of SA (CSA) that sought to Fill that void. The current line of research is aimed at validating that model. The results show that the model accurately predicted SA in a piloted simulation.
Surface models in heterogeneous catalysis: The synthesis of ammonia and the conversion of carbon monoxide

Abstract The establishment of chemical equilibria between gas and solid catalysts during the synthesis of NH 3 and the conversion of CO is considered. Suitable solid-gas equilibrium reactions are discussed. With the correct choice of the rate-controlling step, the equilibrium surface models are able to reproduce the experimental expressions for the rates of reaction. These models represent a drastic departure from the concept of a fixed, heterogeneous surface that has been extensively used in the past for the interpretation of the experimental results on the above reactions. The two approaches, however, complement each other and the validity of each one may well be justified under different experimental conditions. Thus, a model may be considered the extension of the other by modification of some of the parameters of the system.
On the design of highly dispersive photonic crystal waveguides for optical delay lines

We present a design methodology for optimized highly dispersive photonic crystal waveguide delay lines. The results indicate that higher group-indices lower the total propagation loss as long as perturbative backscattering is the dominant loss mechanism.
On the Existence of a Critical Shear Parameter for Cellular Vortex Shedding from Cylinders in Nonuniform Flow

Abstract The results of an experimental and numerical investigation into the existence of a critical shear parameter for cellular vortex shedding are presented. The experimental investigation of vortex shedding from a tapered cylinder in a linear shear flow reveals that vortex shedding is cellular, even when the shear in the flow is high. High shear parameters were achieved by orienting the tapered cylinder such that the shear in the flow added to the effect of the taper in the cylinder. Numerical simulations of the high shear experiment using a diffusive Van der Pol oscillator also indicate cellular shedding. The excellent qualitative and quantitative agreement between the numerical simulations and the experimental results validates a unique linear relationship between the shear parameter and a turbulent kinematic viscosity that scales the diffusive axial coupling term in the model.
Rethinking Research Ethics for Latinos: The Policy Paradox of Health Reform and the Role of Social Justice.

This article discusses the paradox of exclusion/inclusion: U.S. health policy prohibits Latinos who fall under certain classifications from accessing health services and insurance yet permits them to be “human subjects” in health research. We aim to advance the discussion of health research ethics post the Tuskegee syphilis experiment in Latinos by (a) tracing the impacts of policy exclusion and the social context of anti-Latino sentiment on Latinos' low participation rates in health research and inequitable access to treatment modalities; (b) challenging researchers to address social sources of vulnerabilities; and (c) offering recommendations on adapting a social justice ethical stance to address these challenges, which are part of the Tuskegee Study legacy.
Evidence for a human osteosarcoma virus.

ONCOGENIC viruses can induce bone cancer in chickens, rats and mice1,2. A viral aetiology of human osteosarcoma has been suggested but not established. We have induced osteosarcomas in Syrian hamsters by inoculating them at birth with cell-free extracts of human osteosarcomas3,4. In this study, twelve osteosarcomas, nine fibrosarcomas and four benign bone tumours have now developed in inoculated hamsters; six of the malignant tumours have been established as tumour transplant lines.
Multimodality Therapy: Using the Best Available Treatments Together Rationally

Cancer cases comprise an increasingly important part of companion animal practice. As the state of veterinary oncology continues to improve, the combined use of modalities (surgery, chemotherapy, and radiotherapy for the most part, biologic response modification to some extent) will be widely evaluated, and its clinical application will become more common.
Two Placental Hormones Are Agonists in Stimulating Megakaryocyte Growth and Differentiation

Previously, we demonstrated that a placental hormone, PRL-like protein E, stimulates megakaryocyte growth and differentiation. We now find that PRL-like protein E and a second placental hormone, PRL-like protein F (PLP-F), bind the same receptor. PLP-F, which is produced later in pregnancy, might therefore act as either an agonist or antagonist of PRL-like protein E. To resolve this question, we produced recombinant PLP-F in mammalian cell cultures, purified the secreted glycoprotein hormone, and determined its activity in primary mouse bone marrow cultures. PLP-F induces megakaryocyte differentiation and megakaryocyte progenitor growth in a dose-dependent manner, with significant activity detected at a concentration as low as 50 ng/ml. PLP-F in maternal serum reaches at least 1 micro g/ml on gestational d 14.5, and thus the biological activity of PLP-F is detected at physiological concentrations. These results show that PRL-like proteins E and F have the same stimulatory effects on megakaryocyte growth and differentiation, and therefore represent gestation stage-specific agonists.
Implementing computing techniques to accelerate network GIS

We have witnessed the accumulation of petabyes of geospatial data in the past decades, and, currently, terabytes of data are collected every day. These geospatial data are crucial in supporting decision making and emergency response. It becomes increasingly important to deliver these datasets in a timely fashion to the decision support or emergency response systems. Network GIS provides a vehicle to facilitate this delivering process. But to deliver efficiently such large volume of data and to handle large number of concurrent users, the performance of Network GIS needs to be improved to a level that different types of applications, especially near real time applications, can be satisfied. In this circumstance, we 1) review selected research on improving the performance of Network GIs; 2) provide insides on implementing the techniques; and 3) illustrate how to adopt the techniques in Network GIs. We expect the research and development reported here can be easily adopted by different users to accelerate the performance of various Network GIS software and applications, as well as to support the building of spatial data infrastructure to support the sharing of heterogeneous geospatial information.
Dielectric properties of amorphous Nb2O5 thin films

The dielectric constant, a.c. resistance and loss tangent tan δ of amorphous Nb2O5 films with Nb electrodes have been investigated in the frequency range 3 Hz to 5 × 106 Hz, as a function of temperature and applied field. The capacitance decreases with frequency ƒ according to a C(ƒ)∝ƒ−0.3 relation in the range 3 Hz 2 × 10su5 Hz. The activation energy of a dielectric oscillator is 0.032 eV; C−V, G−V and tan δ−V data are presented. The real and imaginary parts of the complex dielectric constant e∗ = e′ − je″ and polarizability α∗ = α′ − jα″ were calculated from the data. The Cole-Cole (e″versus e′), Scaife (α″versus α′) and tan δ versus log ƒ plots indicate the existence of two relaxation times below 8 × 103 Hz. The films are in a thickness range where the principal conduction mechanism is hopping conduction, as shown by the σ(ƒ)∝ƒn relation, with 0.75<n<1 behavior at low fields for 8 × 103 Hz<ƒ<5 × 106 Hz.
Impact excitation of the n=2 fine-structure levels in hydrogenlike ions by protons and electrons.

Quantal close-coupling calculations of the impact excitation of the n=2 fine-structure levels in the hydrogenlike ions ${\mathrm{Ar}}^{17+}$, ${\mathrm{S}}^{15+}$, ${\mathrm{Mg}}^{11+}$, ${\mathrm{C}}^{5+}$, and ${\mathrm{He}}^{+}$ by protons and electrons are presented, and the resulting cross sections and rate coefficients are compared with previous values. The effects of relativity on the proton-impact excitation cross sections for ions with high nuclear charge are investigated. Plasma-density effects on the transition cross sections are explored using a Debye-screening model, and it is shown that the screening of the ion alters the excitation cross sections substantially and brings the ratio of the cross sections towards the statistical value. The calculated transition rates are used to model the ratio of the intensities of the two components of Ly-\ensuremath{\alpha} radiation emitted by impurity hydrogenlike ions in an optically thin, hydrogen plasma. The results confirm that at intermediate plasma densities proton-impact-induced transitions redistribute the n=2 fine-structure-level population ratio away from the statistical value.
Loss of functional specificity in the dorsal striatum of chronic cocaine users.

Abstract Background Although research into the effects of cocaine has focused on the ventral striatum, recent reports have identified a significant role for the dorsal striatum. Given the importance of the dorsal striatum in motor control, the purpose of the present study was to investigate potential sensorimotor deficits among cocaine users and the functional basis of these deficits within the striatum. Methods Functional magnetic resonance imaging data were collected from 14 right-handed, non-treatment seeking chronic cocaine users and 14 age and gender matched controls during performance of two finger-sequencing paradigms that differentially activate the caudate (internally-guided) and the putamen (externally-guided) interleaved with blocks of rest. The total percent signal change in the dorsal striatum and the contribution of the left and right caudate and putamen were calculated and compared across groups and tasks. Results Significant deficits in sensorimotor control were observed in cocaine users for both motor tasks, with the most severe impairments present during internally-guided movements. Cocaine users lacked the typical functional segregation observed in the dorsal striatum of the control subjects. The total percent signal change in the dorsal striatum was not significantly different between the groups, but cocaine users activated significantly less contralateral caudate and putamen for internally-guided versus externally-guided movements, respectively. Conclusion These data provide clear evidence that chronic cocaine users have significant motor performance deficits that are accompanied by disrupted processing within the dorsal striatum. These data suggest the effects of cocaine extend beyond the confines of the motivational domains of the ventral striatum.
Cultured Astrocytes and Neurons Synthesize and Secrete Carboxypeptidase E, a Neuropeptide‐Processing Enzyme

Carboxypeptidase E (EC 3.4.17.10) is a carboxypeptidase B-like enzyme associated with the biosynthesis of many peptide hormones and neurotransmitters. Media collected from cultured astrocytes contain a carboxypeptidase E-like activity. Cultured astrocytes secrete approximately 73% of their cellular level of carboxypeptidase E per hour, and secretion is not substantially influenced by 35 mM KCl. In contrast, neurons secrete only 29% of their cellular carboxypeptidase E per hour, but secretion increases to 86% on stimulation with 35 mM KCl. Secretion of carboxypeptidase E activity from both neuronal and astrocyte cultures is relatively selective; neither acid phosphatase or acetylglucosaminidase is secreted in appreciable amounts. Cultured neurons and astrocytes express a carboxypeptidase E mRNA of a similar size. The levels of this mRNA differ in astrocytes cultured from different brain regions, with high levels in striatal, cortical, hippocampal, and hypothalamic astrocytes and low levels in cerebellar astrocytes. The level of carboxypeptidase E mRNA in hypothalamic astrocyte cultures is four- to fivefold higher than the level in hypothalamic neuronal cultures. These results indicate that cultured astrocytes express carboxypeptidase E mRNA and enzymatic activity and thus contain one of the enzymes required in the biosynthesis of many peptide hormones and neurotransmitters.
Physiologic and Molecular Changes Reflecting Impaired Calcium Cycling in Pacing Induced Heart Failure in Immature Goats |[diams]| 83

In immature animals, effects of pacing-induced heart failure on systolic and diastolic properties and associated changes in Ca2+ handling proteins of the cardiocyte have not been studied. We utilized force-frequency(FFR) and relaxation-frequency relationships (RFR), which reflect changes in Ca2+ cycling by sarcoplasmic reticulum (SR) & sarcolemma (SL). We studied 6 young goats (Age: 4 wks), paced at 300 bpm for a period 2.5 weeks prior to the experiment (P group) and 5 age matched controls (C group). LV dP/dtmax and time constant of relaxation (τ) were calculated from LV micromanometric tracings at increasing heart rates (HR) generated by right atrial pacing after infusing a sinus node blocker. HR at which pulsus alternans appeared was defined as “Critical HR” (HRcrit). Parameters were remeasured after ryanodine, a SR Ca2+ channel release blocker (5 μg/kg). Table
Isolation and identification of male medfly attractive components inLitchi chinensis stems andFicus spp. stem exudates

Short-range attraction/feeding stimulation of male Mediterranean fruit flies [Ceratitis capitata (Wiedemann), (Diptera: Tephritidae)] to a stem extract of a host plant,Litchi chinensis Sonn. (Sapindaceae), and to milky exudates from stems of nonhost plants,Ficus retusa L. andF. benjamina L. (Moraceae), were attributed to the presence of the sesquiterpene α-copaene. The presence of α-copaene in the milky exudate from stems ofF. benghalensis L. is also suggested as eliciting similar behavioral responses in male medflies. The presence of minor quantities of α-ylangene in the plants and its contributory effects to the behavioral response of male medflies is discussed. Short-range attraction/feeding stimulation of male medflies to equal amounts of α-ylangene-free α-copaene samples (94.5%+), prepared from α-copaene-enriched angelica seed oil and copaiba oil, respectively, showed no difference in intensity of response. α-Ylangene elicited a slightly less intense response for male medflies than α-copaene.
Discrete Filters and Transforms to Localize Signal Transitions

Band-pass filters and block-based transforms are developed to retrieve signal discontinuities in sampled data. The filter coefficients are determined from the space or frequency-sampled Laplacian-of-Gaussian filter. The procedure is applied to detect edges in images.
Observations of Jupiter's synchrotron radiation at 18 cm during the comet Shoemaker‐Levy/9 impacts

The results of observations of Jupiter's synchrotron radiation during the period surrounding the impacts of comet Shoemaker-Levy/9 are reported. The observations were made at the Naval Research Laboratory's Maryland Point Observatory 85 foot radio antenna operating at 1665 MHz (18 cm). The data indicate that an increase in the intensity of the synchrotron emission of 23% took place over the full duration of the impact period. The increase was accompanied by two characteristic changes in the beaming curve: a flattening and the creation of brightness temperature variations on hourly timescales. We interpret the latter as longitudinal variations in the beaming curve which suggests a localized mechanism resulting in a redistribution of the radiating electrons in the Jovian radiation belts.
The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.
Pyrolytic carbon-coated vascular prostheses☆

Abstract Pyrolite carbon did not prevent thrombosis in small-caliber vascular grafts. The patency of 4-mm pyrolite carbon-coated grafts (Biolite) implanted in the carotid arteries of dogs was compared to that of uncoated Dacron grafts (Weavenit) and similar-size autogenous veins. There was no difference between coated and uncoated grafts and neither compared favorably with autogenous veins. Short-segment (3-cm-long) carbon-coated grafts healed in the same manner as uncoated grafts by becoming encased in fibrous tissue and developing a smooth neointimal lining. The clotting times on the surfaces of the healed grafts (both coated and uncoated) were the same as those on normal adjacent arteries. Areas of unhealed graft were thrombogenic and their surface clotting times were very short. With the scanning electron microscope, surface irregularities were observed on some coated grafts before they were implanted. These defects may have contributed to poor graft healing and thrombosis. Blood flows through both coated and uncoated prostheses were similar to those observed in normal carotid arteries. Compliances were measured when the animals were sacrificed. Coated and uncoated grafts were not significantly different from each other, but they and the vein grafts were significantly less compliant than normal artery. Graft length was found to be an important determinant of graft patency when 3-cm-long grafts were compared with 10-cm-long grafts.
Psychological maltreatment: Can an integration of research, policy, and intervention efforts be achieved?

McGee and Wolfe's (1991) article has emerged at a critical time, a period during which child abuse and neglect has been declared a national emergency. In the last decade, reports of child abuse have increased dramatically. Unfortunately, the resources available to address the needs of maltreated children have not kept pace with the demand. This distressing state of affairs has caused some social policy theorists to conclude that only the most seriously abused and neglected children should be identified and served so as not to weaken further an already fragile service delivery system (Besharov, 1988; Wald, 1975). In fact, in the absence of greatly enhanced resources, some child advocates have argued that intervention into family life in other than life threatening circumstances may prove to be more detrimental than helpful (Goldstein, Freud, & Solnit, 1979).
The Requirement of Nkx2-1 in the Temporal Specification of Cortical Interneuron Subtypes

Previous work has demonstrated that the character of mouse cortical interneuron subtypes can be directly related to their embryonic temporal and spatial origins. The relationship between embryonic origin and the character of mature interneurons is likely reflected by the developmental expression of genes that direct cell fate. However, a thorough understanding of the early genetic events that specify subtype identity has been hampered by the perinatal lethality resulting from the loss of genes implicated in the determination of cortical interneurons. Here, we employ a conditional loss-of-function approach to demonstrate that the transcription factor Nkx2-1 is required for the proper specification of specific interneuron subtypes. Removal of this gene at distinct neurogenic time points results in a switch in the subtypes of neurons observed at more mature ages. Our strategy reveals a causal link between the embryonic genetic specification by Nkx2-1 in progenitors and the functional attributes of their neuronal progeny in the mature nervous system.
Thermodynamics of Phospholipid Tubules in Alcohol/Water Solutions

Circular dichroism and calorimetry have been used to study the melting of self-assembled phospholipid tubules in alcohol/water solutions. The tubules are found to melt either continuously or discontinuously, depending on the type of alcohol, the alcohol/water ratio, and the lipid concentration. At high proportions of alcohol and low lipid concentrations, the ellipticity continuously decreases with temperature and a very broad peak in the specific heat is observed. In solutions with lower proportions of alcohol or large lipid concentrations, a large drop in ellipticity is accompanied by a sharp peak in the specific heat when the acyl chains disorder. The CD and specific heat measurements can be explained in terms of two distinct thermodynamic processes: the discontinuous melting is a first-order transition of the lipid bilayers from the ordered Lβ‘ phase to the disordered Lα phase, while the continuous melting reflects an increase in the lipid solubility with temperature. These results show that the solve...
A 5-32 bit decoder for application in a crossbar switch

A novel voltage state multiple input NOR gate has been designed and tested for use as the basic gate in a 5-32 b parallel-input decoder. Two versions of this NOR gate are presented, one with a single output and one with a selectable output. The combination of the two types of NOR gate makes it possible to construct a 5-32 b decoder with considerably less gate current than would be required if it were constructed in other logic families. Since only a single gate current is required by each NOR gate and because only 12 NOR gates are needed to build the full decoder, a clock with a peak current level of only 6 mA is sufficient to power all of the decoder's 72 constituent superconducting quantum interference devices (SQUIDs). The decoder also occupies a small area compared with other designs. The authors review critical design issues of the NOR gates, and present low-speed and high-speed results of subblocks of the full 5-32 b decoder. >
Direct resolution of mono- and diol enantiomers of unsubstituted and methyl-substituted benz[a]anthracene and benzo[a]pyrene by high-performance liquid chromatography with a chiral stationary phase

Abstract The direct resolution of 86 structurally related monomethyl, mono-ol, and trans - and cis -diol enantiomers of unsubstituted and methyl-substituted benz-[ a ]anthracene and benzo[ a ]pyrene was investigated by high-performance liquid chromatography with a commercially available column, packed with an ( R )-N-(3,5-dinitrobenzoyl)phenylglycine, ionically bonded to η-aminopropylsilanized silica. The results indicate that structural factors, such as conformation, presence of a methyl substituent, molecular size and shape, and ring saturation all contribute to chiral interactions between the chiral stationary phase and the solutes. Detailed chiral recognition mechanisms can not yet be established, due to complex structural factors that influence enantiomeric resolutions and the lack of data on the absolute configurations of the resolved enantiomers. Nevertheless, the chromatographic method can be applied to the determination of enantiomeric purity of mono- and diol metabolites of polycyclic aromatic hydrocarbons. The absolute configurations of a limited number of resolved enantiomers have been established.
Extirpation experiments on embryonic rudiments of the carapace of Chelydra serpentina.

Somites, along with adjacent neural tube and overlying ectoderm, were extirpated unilaterally from embryos of Chelydra serpentina. Mesoderm of three somites was removed from various levels. The operations included the last formed somite and were done on embryos with 12 to 22 pairs of somites. In practice it was found that ventromedial portions of the somites were not included in the extirpation. The animals were preserved before pigmentation became heavy. The cartilaginous skeleton was stained selectively. The extirpations resulted in depletions of ribs consonant with relating the second rib to the fourteenth somite. The somites behaved as mosaics; they did not reconstitute each other nor did they regenerate after partial extirpation. The rudiments for the ribs were separable from the rudiments of the vertebrae, the sclerotomes, and were found to arise from a more lateral portion of the somite. The scutes are ectodermal derivatives, which are held to be dependent upon underlying somitic mesoderm for their differentiation. The extirpations resulted in abnormalities and depletions of scutes.
Appearance of a second form of hepatic glycerol-3-phosphate dehydrogenase during neonatal development in the mouse.

Abstract Livers of 4-day-old Balb/c mice contain a single form of glycerol-3-phosphate dehydrogenase (GPDH, sn -glycerol-3-phosphate:NAD 2-oxido-reductase, EC 1.1.1.8), which is designated GPDH I. The amount of hepatic GPDH I declines during maturation and levels off by about 6–7 weeks of age. During neonatal development a second form of the enzyme, GPDH II, appears. In mature Balb/c mice (6–7 weeks of age) GPDH II comprises about 30% of the total hepatic GPDH activity. Half-maximal levels of GPDH II are attained by about 18 days postpartum. The rate of appearance of GPDH II is not affected by premature weaning. Hepatic GPDH II is chromatographically distinct from hepatic GPDH I or the embryonic isozyme observed in neonatal brains. Thermal denaturation studies indicate that GPDH I and II from Balb/c mice are denatured at 50 °C with a half-time of about 2 min while the embryonic isozyme is denatured with a half-time of about 30 s. GPDH I and II isolated from C57BL6 mice are denatured at 50 °C with a half-time of 6 min while forms I and II from DDS mice are denatured with a half-time of about 12 min. Kinetic studies reveal that GPDH II and the embryonic isozyme have similar apparent affinities for NADH and dihydroxyacetone phosphate. The apparent affinity of GPDH I for NAD, NADH, dihydroxyacetone phosphate, and glycerol-3-phosphate is lower than that of GPDH II.