cssi/SciSciGPT-SciSciNet huggingface dataset:
Performance comparison of rectangular (four-point) and diagonal (two-point) dither in undersampled infrared focal plane array imagers.

Undersampled staring array imagers exhibit sampling artifacts. Dither is a mechanical means of raising the spatial sampling rate without increasing the number of detectors on the focal plane array. Diagonal (two-point or slant-path) dither is easier to implement than rectangular (four-point or bowtie) dither. Also, diagonal dither generates half the data rate of rectangular dither. However, diagonal dither does not sample the image as effectively as rectangular dither. The cost and complexity advantages of diagonal dither must be traded against the expectation of reduced performance. We discuss analytical and empirical predictions of the performance difference between diagonal and rectangular dither. To compare diagonal and rectangular dither empirically, a target identification (ID) experiment was performed. The visual task involved target ID among a set of 12 tactical vehicles. High-resolution (close-up) images of the targets were blurred and downsampled to produce images representative of those seen with a 320 × 240 pixel staring array sensor. The nondithered imagery was poorly sampled, and the imagery with rectangular dither was adequately sampled. The experiment compared the static target ID performance of nondithered, diagonally dithered, and rectangularly dithered sensors. Analytical and empirical results are described.
Battering in pregnancy: An assessment of two screening methods

Objective: To compare two different screening techniques for identifying women with a history of domestic violence or battering in the current pregnancy. Methods: The five-question Abuse Assessment Screen was incorporated into routine social service interviews and applied prospectively to all registrants for routine prenatal care at Women & Infants' Hospital during an initial social service evaluation from September 7 through October 29, 1993. This group ( N = 143) was compared to a historical control group of all new registrants from July 12 through September 3, 1993 ( N = 191) who had routine interviews by social services. Demographic and medical data were compared, as well as the specific information addressed by the screen, including history of domestic violence, physical or sexual violence within the last year, violence during the current pregnancy, recent sexual abuse, and fear of partner. Results: The median age of the study population was 23 years old, 50% were white, 63% were single, and 42% had no insurance. There was a higher detection of violence in all categories using the Abuse Assessment Screen compared with the standard interview—any history: 41 versus 14% (relative risk [RR] 3.0, 95% confidence interval [CI] 2.0–4.5); recent history: 15 versus 3% (RR 5.6, CI 2.2–14.5); during pregnancy: 10 versus 1% (RR 9.3, CI 2.2–40.5); recent sexual abuse: 4 versus 0% ( P = .006); and fear of abuser: 6 versus 3% (RR 1.8, CI 0.6–5.0). Conclusion: Use of a structured screen improves detection rates of battering both before and during pregnancy, enabling clinicians to have a greater opportunity to intervene.
Persistence of Group A Streptococci in Tissues of Rabbits after Infection.

SummaryGroup A streptococci persisted in the tissues of rabbits, in the absence of bacteremia, for periods up to 104 days following infection. Except in the case of suppurative arthritis such persistence was not associated with any demonstrable pathological lesion. Cortisone might have played a part in reestablishing a bacteremia in rabbits long periods after the acute infection. The significance of these findings in relation to the pathogenesis of rheumatic fever is discussed.
Gene expression and generation of CD28- CD8 T cells mediated by interleukin 15

Abstract Accumulation of CD28 − CD8 T cells that are defective in response to antigenic stimulation is a hallmark of age-associated decline in T cell function. However, the underlying mechanism of this age-associated change is not fully understood. We recently analyzed the global gene expression profiles of CD8 T cell subsets from nai¨ve to memory (CD28 + to CD28 − ) cells and the growth of CD28 + and CD28 − CD8 memory T cells in response to homeostatic cytokine interleukin 15 (IL-15). At the gene expression level, one of the most striking changes is the altered expression of some co-stimulatory receptors and various NK cell receptors in CD28 − CD8 T cells. Furthermore, CD28 − CD8 T cells appear to have a normal proliferation response to IL-15 in vitro. Interestingly, IL-15 is also capable of inducing stable loss of CD28 expression in actively dividing CD28 + CD8 memory T cells. Together, these findings provide the gene expression features of CD28 − CD8 T cells that differ from their CD28 + counterparts and suggest a possible role of IL-15 in the increase of CD28 − CD8 T cells that occurs with aging.
Isotope effects and the mechanism of palladium-catalyzed allylic alkylation

The palladium-catalyzed allylic alkylation reaction of 1,1-dimethylallyl acetate with dimethyl malonate is studied by a combination of isotope effects and theoretical calculations. A large 13C isotope effect of ≈1.037 is observed at the tertiary carbon, while small isotope effects are observed at the olefinic carbons. These results support rate-limiting ionization of a η2-Pd complex. The observed isotope effects are compared with predictions from calculational models employing either solvent models or ionization of an amidinium ion. The calculated transition structures are notably η2 in character, and the implications of this observation are discussed.
Time-dependent radiative transfer in inhomogeneous and dispersive media: application to multimode fibers

The traditional theory of radiative transfer has been generalized to make it more readily applicable to inhomogeneous media and dispersive systems. This was done by incorporating the idealized ray paths of the region under study into the time-dependent equation of transfer and permitting group-velocity variations among the rays. The use of idealized ray paths, instead of the assumption of rectilinear propagation, can greatly simplify the scattering functions of some media. An operator calculus was used to develop a scattering series solution to the time-dependent equation of transfer. The first-order solution was applied to the problem of pulse dispersion in multimode fibers. When supplemented by the appropriate fiber models, the theory proved useful for investigating the contributions of various phenomena to the complex problem of pulse dispersion.
ACM president's letter: eating our seed corn

On July 12 and 13, 1980, the biennial meeting of Computer Science Department chairmen was held at Snowbird, Utah. This meeting, which is organized by the Computer Science Board (CSB), is a forum for the heads of the 83 departments in the United States and Canada that grant Ph.D.s in Computer Science. The meeting was attended by 56 department heads or their representatives, and by six observers from industry and government. This report was developed during the meeting as a result of intensive discussions about the crisis in Computer Science. This report was endorsed by the entire assembly.
Effect of nicotine on cardiac necrosis induced by corticosteroid-electrolyte-stress☆

Abstract Myocardial necrosis was produced in rats by the following regimen: daily injections of dexamethasone and desoxycorticosterone acetate, and gavage with a solution of monobasic sodium phosphate for 5 days, followed by 712 hours of restraint on the sixth day. Separate groups given the above-described treatment were concomitantly administered 0.14, 0.57, and 2.28 mg. per kilogram per day of nicotine alkaloid in the drinking water. Either phenelzine, 1 mg. per kilogram, or mecamylamine, 12.5 mg. per kilogram, was administered daily to separate groups given the steroid-salt-stress treatment and to other groups also administered 2.28 mg. per kilogram per day of nicotine. Reserpine, 1 μg per animal per day, was injected alternately 3 or 7 days prior to, and also during, steroid-salt-stress treatment, both with and without the administration of 2.28 mg. per kilogram per day of nicotine. The two higher doses of nicotine significantly (P Treatment with mecamylamine or phenelzine did not reduce the response to the steroid-salt-stress treatment, but significantly (P
Modification of the effect of dimethyl sulfoxide on intracranial pressure, brain water, and electrolyte content by indomethacin.

Albino rabbits with experimental brain oedema produced by a combined cryogenic left hemisphere and a metabolic 6-aminonicotinamide lesion were given indomethacin (20 mg/kg) fifteen minutes prior to dimethyl sulfoxide (DMSO) treatment (1 g/kg bolus). Intracranial pressure (ICP), systolic arterial pressure (SAP), central venous pressure (CVP), and EEG were continuously measured while the animals were being mechanically ventilated at a constant PaCO2 (38–42 torr). At the end of the run, brain H2O and electrolytes were measured. There was no significant reduction in ICP at 5 minutes and 15 minutes after DMSO. This was strikingly different to what occurred when DMSO alone was administered, when a significant reduction was noted (p<0.05). At 30 minutes there was a reduction in ICP in both the DMSO and the DMSO/indomethacin groups, but in the former it was 50% of the pretreatment values while in the latter it was only 24%. Because indomethacin is a proven prostaglandin inhibitor, these results suggest that these substances may play a role in the mechanism of action of DMSO.
Factors Affecting Recurrence following Incisional Herniorrhaphy

The purpose of this study was to determine the influence of chronic illness, obesity, and type of repair on the likelihood of recurrence following incisional herniorrhaphy. The medical records of 77 patients who underwent elective repair of a midline incisional hernia at the Dallas Veterans Affairs Medical Center between 1991 and 1995 were reviewed. Demographic data, presence of chronic illnesses, type of repair, and presence of recurrence were noted. Ninety-six percent of the patients were men, with an average age of 59 years. More than 50% of the patients had chronic lung or cardiac diseases and more than 40% weighed ≥120% of their ideal body weight and had a body mass index (BMI) ≥30. Sixty-two percent of the patients underwent primary reapproximation of the fascia (tissue repair), whereas 38% underwent repair with prosthetic material (prosthetic repair). The overall recurrence rate was 45%, with a median follow-up of 45 months (range 6–73). Seventy-four percent of the recurrences presented within 3 years of repair. The recurrence rate for those patients undergoing a tissue repair was 54%, whereas the recurrence rate following prosthetic repair was 29%. The incidence of recurrence for patients with pulmonary or cardiac disease or diabetes mellitus was similar to that of patients without these illnesses. The percent ideal body weight and BMI of patients who developed a recurrent hernia, particularly following a prosthetic repair, were significantly greater than those of patients whose repairs remained intact. These data strongly support the use of prosthetic repairs for incisional hernias, particularly in patients who are overweight.
Funerals, Family, and Forefathers: A View of Italian-American Funeral Practices:

Italian-American funeral practices have received little attention in the literature. This study deals with this gap by tracing the evolution of funeral practices from the Old World, preimmigrant culture of the southern Italian to the contemporary New World funeral practices of Italian-Americans reflective of the so-called American way of death.The article is structured around the thesis that the author's own family experience of the ritualistic observance of death had its roots in Old World customs and traditions, was subsequently modified by American social patterns, secularism, industrialization, and funeral customs, and was further shaped by particular psychosocial family dynamics.The concluding section compares the author's personal experience of Roman Catholic home funerals with the larger societal practices described.
Rural breast cancer treatment: evidence from the Reaching Communities for Cancer Care (REACH) project.

Background. Research shows that rural populations are more likely than their urban counterparts to be diagnosed with late‐stage cancer, but less is known about appropriateness of cancer treatment in rural locations after diagnosis. The objective of this analysis was to assess the degree to which rural breast cancer treatment was received in concordance with national recommendations. Methods. Data came from 251 stage I and II breast cancer patients residing in rural North Carolina. State‐of‐the‐art care was defined using the National Cancer Institute's (NCI) physician data query (PDQ) database, and cases were categorized into appropriate primary and/or adjuvant treatment. Chi‐square and Fishers' exact tests were used to assess changes in appropriate treatment over time (1991–1996) and between stage. Multiple logistic regression was used to determine whether any patient or disease characteristics were associated with receipt of appropriate treatment. Results. Most (81–90%) of the breast cancer cases received the appropriate primary therapy (mastectomy or lumpectomy followed by radiation therapy); of these, the majority received a mastectomy (66–72%). Fewer women received adjuvant therapy as recommended (27–61%), although significantly more stage II than stage I cases did so (p≤0.05). Regression showed that stage and estrogen‐receptor (ER) status were associated with appropriate therapy. Conclusions. The findings suggest that there exist deviations from NCI established treatment recommendations among rural breast cancer patients. More research is needed to develop better methods for dissemination of state‐of‐the‐art cancer information to rural physicians and patients, and to understand how treatment decisions are made.
A study of regrowth interface and material quality for a novel InP-based architecture

This work examines a new technology, coupling the use of a quantum-well-intermixing processing platform and an offset quantum-well regrowth. Achieving a high material quality regrowth on a surface subjected to heavy processing and defect diffusion during the intermixing process is vital to the performance of the offset quantum wells. Using photoluminescence, atomic force microscopy, and fabricating broad area lasers, we demonstrate for the first time that good material quality can be achieved when regrowing on surfaces with intermixed material beneath. Further, we achieve regions of high and low optical confinement on the same chip.
To Co-Author or Not to Co-Author: How to Write, Publish, and Negotiate Issues of Authorship with Undergraduate Research Students

This Teaching Resource emphasizes the value of publishing with undergraduates and may be particularly helpful to incoming faculty who are new to the process of working with students. Beyond simply extolling the virtues of undergraduate research, we examine how such deep learning experiences for students can translate into unique opportunities for the faculty to demonstrate devotion to both teaching and scholarship. Along with highlighting the reasons faculty should consider publishing with undergraduates, we identify the particular challenges that accompany this suggestion and discuss strategies for overcoming them. Our resource includes two decision trees for helping faculty determine whether publishing with undergraduates represents a reasonable and attainable goal and whether an undergraduate has earned authorship. Based on our experience at primarily undergraduate institutions, we provide a list of strategies that may facilitate writing with undergraduates and lead to certain milestones in the careers of both students and faculty.
Deformation mechanism and fibre toughening of nylon 6,6

Abstract The effects of glass-fibre reinforcement on the fracture toughness, KIC, of nylon 6,6 were examined and the deformation mechanisms of unreinforced nylon 6,6 were studied by varying the deformation rate, by dilatational measurements and by i.r. spectroscopy. In the unreinforced nylon 6,6 a flow stress plateau was observed in the stress-strain behaviour prior to the onset of necking. Of the 25–30% inelastic strains stored in this plateau a substantial portion appears to be related to a crystallographic plastic deformation due to the crystalline segments in nylon 6,6. In glass-fibre-reinforced nylon 6,6 a brittle to ductile transition was found to occur when the mean fibre-end spacing was less than a critical value. The observed brittle-ductile transition was found to originate from an observed enhanced matrix plasticity at fibre ends when the glass fibres are sufficiently closely spaced. Such enhanced localized plasticity at fibre ends was suggested to result from interactions of stress fields with nearby fibre ends when the fibre-end spacing is less than the critical value. It is further postulated that the enhanced localized fibre-end plasticity is made possible due to the ability of the matrix to exhibit a large degree of crystallographic plasticity. The toughening behaviour of fibre-reinforced nylon 6,6 was also compared qualitatively to that of rubber-toughened nylon 6,6 and a general principle for microstructural toughening in nylon 6,6 was addressed. Strategies for fibre toughening in fibre-reinforced nylon 6,6 were also discussed.
Monocularly produced compound afterimages

A compound afterimage is reported after sequential presentation to the same eye of two orthogonally-oriented patterns. The compound’s duration is comparable to the duration of the unitary state of an afterimage following single exposure of a two-orientation pattern, and is governed by spatiotemporal luminance parameters. It is suggested that afterimage duration measurement will lead to an understanding of afterimage visibility mechanisms while also providing noninvasive means for investigating cortical orientation processes in the spatial and temporal domain.
A Priori Prediction of Tumor Payload Concentrations: Preclinical Case Study with an Auristatin-Based Anti-5T4 Antibody-Drug Conjugate

The objectives of this investigation were as follows: (a) to validate a mechanism-based pharmacokinetic (PK) model of ADC for its ability to a priori predict tumor concentrations of ADC and released payload, using anti-5T4 ADC A1mcMMAF, and (b) to analyze the PK model to find out main pathways and parameters model outputs are most sensitive to. Experiential data containing biomeasures, and plasma and tumor concentrations of ADC and payload, following A1mcMMAF administration in two different xenografts, were used to build and validate the model. The model performed reasonably well in terms of a priori predicting tumor exposure of total antibody, ADC, and released payload, and the exposure of released payload in plasma. Model predictions were within two fold of the observed exposures. Pathway analysis and local sensitivity analysis were conducted to investigate main pathways and set of parameters the model outputs are most sensitive to. It was discovered that payload dissociation from ADC and tumor size were important determinants of plasma and tumor payload exposure. It was also found that the sensitivity of the model output to certain parameters is dose-dependent, suggesting caution before generalizing the results from the sensitivity analysis. Model analysis also revealed the importance of understanding and quantifying the processes responsible for ADC and payload disposition within tumor cell, as tumor concentrations were sensitive to these parameters. Proposed ADC PK model provides a useful tool for a priori predicting tumor payload concentrations of novel ADCs preclinically, and possibly translating them to the clinic.
Effects of methrpyrilene measured in mitochondria isolated from naive and methapyrilene-treated rat and mouse hepatocytes

Methapyrilene (MP) is a rat-specific liver carcinogen that alters mitochondrial number and morphology both in vivo and in vitro. This biological phenomenon may be due to the effects of MP on mitochondrial function. To test this hypothesis, studies were conducted to examine the effects of MP on DNA and protein synthesis and respiration in isolated mitochondria. DNA and protein synthesis activities were measured using [3H]thymidine and [3H]leucine incorporation. Mouse liver mitochondria were also examined for comparison since no tumor formation or alterations in mitochondrial morphology have been associated with MP treatment in mice. A signicant decrease in basal DNA and protein synthesis levels was observed in mitochondria isolated from rats and mice following in vivo MP treatment. This effect could not be reproduced when mitochondria were exposed to 0 or 100 μm MP following isolation, despite the presence of an S9 activation system. Electron microscopic examinations were performed on isolated rat mitochondria and revealed morphologic differences between mitochondria from naive and MP-treated rats. Although significant differences in State 3 and State 4 respiratory rates were noted, the respiratory control ratio, ADPO ratio, and uncoupler-stimulated respiratory rates were unaffected. Results demonstrate that: (1) MP irreversibly depresses DNA and protein synthesis in a majority of mitochondria, despite only localized morphologic changes; (2) these changes are not reflected by a decrease in respiratory function; and (3) depression of DNA and protein synthesis does not correlate with carcinogenic susceptibility.
Some unlikely properties of the likelihood ratio and its logarithm

It is well known that the optimum way to perform a signal-detection or discrimination task is to compute the likelihood ratio and compare it to a threshold. Varying the threshold generates the receiver operating characteristic (ROC) curve, and the area under this curve (AUC) is a common figure of merit for task performance. AUC can be converted to a signal-to-noise ratio, often known as d a , using a well-known formula involving an error function. The ROC curve can also be determined by psychophysical studies for humans performing the same task, and again figures of merit such as AUC and d a can be derived. Since the likelihood ratio is optimal, however, the d a values for the human must necessarily be less than those for the ideal observer, and the square of the ratio of d a (human)/d a (ideal) is frequently taken as a measure of the perceptual efficiency of the human. The applicability of this efficiency measure is limited, however, since there are very few problems for which we can actually compute d a or AUC for the ideal observer. In this paper we examine some basic mathematical properties of the likelihood ratio and its logarithm. We demonstrate that there are strong constraints on the form of the probability density functions for these test statistics. In fact, if one knows, say, the density on the logarithm of the likelihood ratio under the null hypothesis, the densities of both the likelihood and the log-likelihood are fully determined under both hypotheses. Moreover, the characteristic functions and moment-generating functions for the log-likelihood under both hypotheses are specified in terms of a likelihood-generating function. From this single function one can obtain all moments of both the likelihood and the log-likelihood under both hypotheses. Moreover, AUC is expressed to an excellent approximation by a single point on the function. We illustrate these mathematical properties by considering the problem of signal detection with uncertain signal location.
Control of human norovirus surrogates in fresh foods by gaseous ozone and a proposed mechanism of inactivation.

Fresh produce is a major concern for transmission of foodborne enteric viruses as it is normally consumed with no heat treatments and minimal other processing to ensure safety. Commonly used sanitizers are ineffective at removing foodborne viruses from fresh produce. Thus the use of gaseous ozone for viral inactivation was investigated. Ozone has great potential for improved food safety because of four benefits: It is a potent sanitizer, it is effective against a wide range of microorganisms, it is permitted for food use as regulated by the U.S. FDA and several other nations, and it spontaneously decomposes to oxygen leaving no residue. This study determined the effectiveness of gaseous ozone for the sanitization of two norovirus surrogates (MNV-1 and TV) from both liquid media and popular fresh foods where viral contamination is common-lettuce and strawberries. Foods were treated with gaseous ozone at 6% wt/wt ozone in oxygen for 0, 10, 20, 30, and 40 min, and surviving viruses were quantified by viral plaque assay. Our results showed that gaseous ozone inactivated norovirus in both liquid media and fresh produce in a dose-dependent manner. These results are promising because ozone treatment significantly reduced two important norovirus surrogates in both liquid and food matrices. Viruses are generally more resistant to sanitation treatments than bacteria, thus gaseous ozone is an effective means to improve fresh produce safety.
Electrical resistivities of solid and liquid Pr, Nd and Sm

The authors have measured the electrical resistivities rho , of the light rare-earth metals, Pr, Nd and Sm from room temperature to above their melting points. They find, for the liquid phases at their various melting points, that the values of rho L are 139+or-2, 154+or-2 and 182+or-2 mu Omega cm for Pr, Nd and Sm, respectively. Similarly, d rho L/dT values are measured to be 0.035+or-0.0003, 0.023+or-0.002 and 0.052+or-0.004 mu Omega cm degrees C-1, again for Pr, Nd and Sm respectively. These results as well as measurements of rho (T) in the solid phases are discussed in the context of recent theoretical work.
Right ventricular phenotypic characteristics in subjects with primary pulmonary hypertension or idiopathic dilated cardiomyopathy

Abstract Background: Studies of animal models and human subjects with cardiomyopathies suggest that cardiac myocyte and ventricular chamber remodeling show distinct phenotypic characteristics that may be dependent on specific signaling pathways. Methods and Results: In this study, we characterize right ventricular (RV) chamber size, end-diastolic thickness, myocardial mass, and ejection fraction (EF) in human subjects with chronic heart failure from primary pulmonary hypertension (PPH; n = 10) and idiopathic dilated cardiomyopathy (IDC; n = 10). Subjects underwent gated cardiac magnetic resonance imaging (MRI), and the RVs were phenotypically classified based on the presence or absence of hypertrophy (increased mass), systolic dysfunction (reduced EF), and degree of wall thickness (concentric v eccentric pattern of hypertrophy). Within this schema, five abnormal phenotypes could be identified. In PPH subjects, in whom the RV is subjected to the uniform insult of chronic pressure overload, four different abnormal phenotypes were identified. Conclusions: These data indicate that distinct structural/functional ventricular chamber phenotypes may be classified by MRI, and that a uniform insult can result in multiple RV phenotypes.
Constituents of craving in a clinical alcohol sample.

Abstract Purpose: Craving describes a subjective state, and it remains unclear what people mean when they use the term. However, as with many other subjective states, craving should be able to be described by those who experience it. Methods: To try to understand the descriptors and constituents of craving, 213 clients appearing for treatment for alcohol use disorders were asked to rate the frequency of the occurrence over the past 30 days of a number of events and states that have been historically regarded as part of craving. These clients were also asked to rate the frequency with which they had experienced craving and urges over the same period. Using discriminant function analysis (DFA), some states were elucidated that separated those who reported craving from those who did not. Results and implications: Those who reported craving consistently reported the occurrence of more dysphoric states, more of certain physical feelings associated with thoughts of alcohol, more thoughts of alcohol, and desiring alcohol when confronted with environmental cues. Such descriptions may aid in establishing reliable criteria for understanding the constituents of craving.
The qualitative determination of some organic compounds in marine sediments

Abstract Four sediment samples from the Caribbean Sea were analysed qualitatively for free sugars, amino acids and simple organic acids. Two of the samples were from an anaerobic basin; two were from aerobic areas. The sediments were extracted with hot water and 70 per cent ethanol and the residues from these extractions were hydrolysed with 6 N hydrochloric acid. The organic materials in the extracts were separated and studied qualitatively on paper chromatograms. Six free sugars, eight amino acids and seven acids were detected in one or more of the sediments analysed.
Andromonoecism, protandry, and sexual selection in Umbelliferae

Abstract Most Umbelliferae are protandrous and andromonoecious with hermaphrodite flowers concentrated in earlier opening umbellets and umbel orders. When weakly developed: protogyny is more effective than protandry in promoting outcrossing, yet is uncommon. It ts suggested that sexual selection, rather than selection for outcrossing, explains the Widespread occurrence of protandry. When protandry is strongly developed, male and female phases may be completely separated in time within a plant so that outcrossing is assured.
Integrate-and-fire neuron modeled as a low-rate sparse time-encoding device

Neurons as Time Encoding Machines (TEMs) have been proposed to capture the information present in sensory stimuli and to encode it into spike trains [1], [2], [3]. These neurons, however, produce spikes at firing rates above Nyquist, which is usually much higher than the amount of information actually present in stimuli. We propose a low-rate spiking neuron which exploits the sparsity or compressibility present in natural signals to produce spikes at a firing rate proportional to the amount of information present in the signal rather than its duration. We consider the IAF (Integrate-and-Fire) neuron model, provide appropriate modifications to convert it into a low-rate encoder and develop an algorithm for reconstructing the input stimulus from the low-rate spike trains. Our simulations with frequency-sparse signals demonstrate the superior performance of the Low-Rate IAF neuron operating at a sub-Nyquist rate, when compared with IAF neurons proposed earlier, which operate at and above Nyquist rates.
Orbital-band interactions and the reactivity of molecules on oxide surfaces: from explanations to predictions

The surface chemistry of oxides is relevant for many technological applications: catalysis, photoelectrolysis, electronic-device fabrication, prevention of corrosion, sensor development, etc. This article reviews recent theoretical works that deal with the surface chemistry of oxides. The account begins with a discussion of results for the adsorption of CO and NO on oxides, systems which have been extensively studied in the literature and constitute an ideal benchmark for testing the quality of different levels of theory. Then, systematic studies concerned with the behavior of adsorbied alkali metals and sulfur-containing molecules are presented. Finally, a correlation between the electronic and chemical properties of mixed-metal oxides is analyzed and basic principles for designing chemically active oxides are introduced. Advances in theoretical methods and computer capabilities have made possible a fundamental understanding of many phenomena associated with the chemistry of molecules on oxide surfaces. Still many problems in this area remain as a challenge, and the approximate nature of most theoretical methods makes necessary a close coupling between theory and experiment. Following this multidisciplinary approach, the importance of band-orbital interactions for the reactivity of oxide surfaces has become clear. Simple models based on band-orbital mixing can explain trends found for the interaction of many adsorbates with oxide surfaces. These simple models provide a conceptual framework for modifying or controlling the chemical activity of pure oxides and for engineering mixed-metal oxides. In this respect, theoretical calculations can be very useful for predicting the best ways for enhancing the reactivity of oxide systems and reducing the waste of time, energy and materials characteristic of an empirical design.
A Simple Karl Fischer Titration Technique for Measuring the Silanol Content of High Molecular Weight Polysiloxanes

This article presents a simple technique for measuring the silanol (SiOH) content of polysiloxanes having molecular weights of 26,000 amu or more. It extends an earlier procedure,[ 1 ] in which 50°C methanol converts each silanol group into a methoxy group (SiOCH3) and the resulting water is measured by Karl Fischer titration. Unlike previous work, however, the present technique dissolves the high molecular weight polysiloxanes in a mixture of chloroform and methanol and observes the exponential decay of the remaining silanol groups. A fit to that decay curve determines the initial silanol content and excludes water initially present in the polysiloxane.
Mapping the Sovereign State: Technology, Authority, and Systemic Change

This article examines the effect of cartography on the development of the modern state system. I argue that new mapping technologies in early modern Europe changed how actors thought about political space, organization, and authority, thus shaping the creation of sovereign states and international relations. In particular, mapping was fundamental to three key characteristics of the medieval-to-modern shift: the homogenization of territorial authority, the linearization of political boundaries, and the elimination of nonterritorial forms of organization. Although maps have been interpreted as epiphenomenal to political change, each of these three transformations occurred first in the representational space of maps and only subsequently in the political practices of rulers and states. Based on evidence from the history of cartographic technologies and their use by political actors, the practices and texts of international negotiations, and the practical implementation of linearly bounded territoriality by states, this article argues that changes in the representational practices of mapmaking were constitutive of the early-modern transformation of the authoritative structure of politics. This explanation of the international system's historical transformation suggests useful new directions for investigations into the possibility of fundamental political change due to the economic, social, and technological developments of globalization.
Some physiological factors in noise-induced hearing loss.

Abstract Loss of auditory sensitivity following exposure to noise is the result of metabolic and structural alteration within the sensory cells of the organ of Corti. Similar changes can be caused by other agents which do not produce a recognizable change in hearing. However, noise is always superimposed upon the physiological state of the sensory epithelium, and this may determine the final affects of the noise. The source of nutrients for the sensory cells is the arcade of vessels lying beneath the basilar membrane. Localized occlusion of these vessels eventually produces degeneration of these sensory cells. Certain conditions produce constriction of some of these vessels, resulting in diminished blood supply and reduction in the metabolic state of the sensory cells. Superimposing overstimulation on these cells at this time would most likely have a destructive effect.
A case study of cross-system porting in forked projects

Software forking---creating a variant product by copying and modifying an existing product---is often considered an ad hoc, low cost alternative to principled product line development. To maintain such forked products, developers often need to port an existing feature or bug-fix from one product variant to another. As a first step towards assessing whether forking is a sustainable practice, we conduct an in-depth case study of 18 years of the BSD product family history. Our study finds that maintaining forked projects involves significant effort of porting patches from other projects. Cross-system porting happens periodically and the porting rate does not necessarily decrease over time. A significant portion of active developers participate in porting changes from peer projects. Surprisingly, ported changes are less defect-prone than non-ported changes. Our work is the first to comprehensively characterize the temporal, spatial, and developer dimensions of cross-system porting in the BSD family, and our tool Repertoire is the first automated tool for detecting ported edits with high accuracy of 94% precision and 84% recall. Our study finds that the upkeep work of porting changes from peer projects is significant and currently, porting practice seems to heavily depend on developers doing their porting job on time. This result calls for new techniques to automate cross-system porting to reduce the maintenance cost of forked projects.
Tribochemical studies by XPS analysis of transfer films of Nylon 11 and its composites containing copper compounds

Abstract The transfer films of Nylon 11 and its composites with CuS, CuAc and CuF 2 formed on the steel disk surfaces were studied by X-ray photoelectron spectroscopy. The study revealed that CuS and CuF 2 decomposed under the rubbing conditions and produced copper, FeF 6 group and FeSO 4 . The analysis at different depths in the transfer films indicated higher concentrations of these species closer to the transfer film-counterface interface. There was no chemical change detected when unfilled Nylon 11 and CuAc-Nylon composite rubbed against the steel disk surfaces. These results have been used to hypothesize the mechanism by which the transfer films of these materials influence wear.
Endoscopic findings and their clinical correlations in patients with symptoms after gastric bypass surgery.

Abstract Background The aim of this study was to describe the endoscopic findings in patients with upper GI symptoms after Roux-en-Y gastric bypass surgery and to correlate clinical features with endoscopic findings. Methods Patients with symptoms after Roux-en-Y gastric bypass referred for endoscopy were studied. Endoscopy was performed in standard fashion with a 9.8-mm diameter endoscope. Results Forty-nine patients underwent a total of 69 upper endoscopy procedures between January 2001 and February 2003. The most common endoscopic findings were the following: normal post-surgical anatomy (21 patients, 43%), marginal ulcer (13 patients, 27%), stomal stenosis (9 patients [19%], including 5 with a concomitant marginal ulcer), and staple-line dehiscence (8 patients [16%], including one with a marginal ulcer). Abdominal pain was the most common symptom (26 patients, 53%) and was more frequent among patients with a normal endoscopy compared with those with an abnormal endoscopy ( p =0.04). Stomal stenosis was present in 39% of patients with nausea, vomiting, or dysphagia; it was not present in any patient without these symptoms ( p =0.001). Fifteen percent of procedures performed within the first 6 postoperative months were normal, compared with 53% of those performed beyond 6 months ( p =0.02). There was no complication of endoscopy. Conclusions Among patients with symptoms after Roux-en-Y gastric bypass presenting for endoscopy, normal post-surgical anatomy was the most common finding. Marginal ulcer was the most common abnormality. Presentation with abdominal pain and performance of endoscopy beyond the 6th post-operative month were predictive of a normal endoscopy, and lack of nausea, vomiting, and dysphagia predicted the absence of stomal stenosis.
The Morning Blood Pressure Surge: Therapeutic Implications

Adverse cardiovascular events such as myocardial infarction, stroke, arrhythmias, and sudden cardiac death are well known to follow a circadian pattern, peaking in the morning hours of 6 AM to 12 PM. Many physiologic factors have been shown to follow a circadian pattern and together may create an environment that promotes intraluminal thrombi formation. Blood pressure follows this pattern with a "dip" at night and an increase on awakening. This morning surge may lead to hemodynamic forces that predispose patients to plaque rupture. The clinical impression of these known physiologic patterns associated with adverse cardiovascular events suggests that a strict treatment schedule targeting this phenomenon is needed. The goal of this review is to provide clinicians with an overview, allowing for informed decisions about chronotherapeutic formulations tailored to provide blood pressure control throughout the day and night.
Significance of Nucleation Kinetics in Sn Whisker Formation

Sn whiskers are believed to form in response to stress in layers used as protective coatings. However, what makes them form at specific sites on the surface is not known. We have used thermal expansion mismatch to induce stress and observe the resulting whisker formation. Cross-sectional measurements of the region around whiskers show that there are oblique grain boundaries under the whiskers that are not seen in the as-deposited columnar structure. The kinetics also suggest that the whiskering sites may be formed by a nucleation process. Based on these results, we propose a nucleation mechanism in which the boundaries of the surrounding grains migrate due to strain energy differences and create oblique boundaries at which whiskers can form. A simple model is developed to predict the stress-dependence of the nucleation rate.
N14 nuclear quadrupole resonance in compounds used as intercalates in superconducting complexes of TaS2

Abstract The nitrogen quadrupole resonance (NQR) frequencies of nitrogen-containing organic molecules are found to correlate with the enhancement in the superconducting critical temperature T c caused by intercalating these molecules in layered tantalum disulfide (2HTaS 2 ). This correlation of NQR frequencies (measured before intercalation) with T c provides a basis for predicting T c values for molecules with known charge distributions, determining the details of charge transfers from intercalate to lavered chalcogenide, and selecting intercalates which may achieve optimal values of T c .
Empowering technology: Implementing a U.S. strategy

Technology policy - whether we should have one and what form such a policy should take - was a core issue of the 1992 presidential campaign, and in February 1993 the Clinton administration confirmed that fostering new technologies will be a critical part of its agenda for redirecting the American economy. To help orient the inevitable debates on this agenda, experts from Harvard's Center for Science and International Affairs here examine a set of key issues and problems that, taken together, define the scope and limits of such a policy.Among the topics discussed are the new relationship between federal and state governments implied by the administration's proposals, the usefulness of the concept of "critical technologies" for setting priorities, the creation of new missions for the national laboratories (particularly the three weapons laboratories), the changing nature of the social contract between the government and research universities, the problems that will confront the creation of a national information infrastruc-ture, the best ways to promote small- -and medium-sized "driver" companies as well as civilian research and development generally, and the relationship between education and the requirements for work in the twenty-first century. Lewis M. Branscomb is Albert Pratt Public Service Professor and Director of the Science, Technology, and Public Policy Program at the Center for Science and International Affairs, Harvard University.
Generation and Characterization of ATP Analog-specific Protein Kinase Cδ

To better study the role of PKCδ in normal function and disease, we developed an ATP analog-specific (AS) PKCδ that is sensitive to specific kinase inhibitors and can be used to identify PKCδ substrates. AS PKCδ showed nearly 200 times higher affinity (Km) and 150 times higher efficiency (kcat/Km) than wild type (WT) PKCδ toward N(6)-(benzyl)-ATP. AS PKCδ was uniquely inhibited by 1-(tert-butyl)-3-(1-naphthyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (1NA-PP1) and 1-(tert-butyl)-3-(2-methylbenzyl)-1H-pyrazolo[3,4-d]pyrimidin-4-amine (2MB-PP1) but not by other 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP1) analogs tested, whereas WT PKCδ was insensitive to all PP1 analogs. To understand the mechanisms for specificity and affinity of these analogs, we created in silico WT and AS PKCδ homology models based on the crystal structure of PKCι. N(6)-(Benzyl)-ATP and ATP showed similar positioning within the purine binding pocket of AS PKCδ, whereas N(6)-(benzyl)-ATP was displaced from the pocket of WT PKCδ and was unable to interact with the glycine-rich loop that is required for phosphoryl transfer. The adenine rings of 1NA-PP1 and 2MB-PP1 matched the adenine ring of ATP when docked in AS PKCδ, and this interaction prevented the potential interaction of ATP with Lys-378, Glu-428, Leu-430, and Phe-633 residues. 1NA-PP1 failed to effectively dock within WT PKCδ. Other PP1 analogs failed to interact with either AS PKCδ or WT PKCδ. These results provide a structural basis for the ability of AS PKCδ to efficiently and specifically utilize N(6)-(benzyl)-ATP as a phosphate donor and for its selective inhibition by 1NA-PP1 and 2MB-PP1. Such homology modeling could prove useful in designing molecules to target PKCδ and other kinases to understand their function in cell signaling and to identify unique substrates.
HIGHLY BRANCHED DENDRITIC MACROMOLECULES WITH CORE POLYHEDRAL SILSESQUIOXANE FUNCTIONALITIES

Reaction of the first and second generations of monodendrons, bearing peripheral 2,2‘:6‘,2‘‘-terpyridine units (tpy) and focal point benzylic bromine, with phosphine-substituted silsesquioxane Si8O12(CH2CH2PPh2)8 in refluxing THF affords the corresponding dendritic macromolecules with encapsulated polyhedral silsesquioxane cores. The synthesis of such molecules and their characterization by 1H, 13C, 31P{1H}, and 29Si NMR, as well as fast atom bombardment (FAB/MS) and electrospray (ESI/MS) mass spectral analysis, are described herein.
Promoting oral hygiene in pediatric dentistry: A critical review

Abstract Dental caries have been described by the U.S. Surgeon General as the nation's most common health problem. Also, up to 65% of children suffer from periodontal disease, another dental disorder that may result in tooth loss. Both of these disorders are directly attributable to the effects of dental plaque. The consensus is that the best way of controlling plaque is through brushing and flossing. Unfortunately, many of the studies designed to promote these oral hygiene behaviors have yielded either clinically insignificant results, or results that were not maintained after the termination of treatment. In this article, the literature on the effects of dental plaque, the assessment of oral hygiene programs, and the various treatment approaches for promoting oral hygiene are reviewed.
Transient Performance and Behaviour of Gas Turbine Engines

The paper deals with some activities carried out for setting up and using numerical computer codes for simulating the behaviour of gas turbine engines during transient operations.Copyright © 1990 by ASME