cssi/SciSciGPT-SciSciNet huggingface dataset:
Positive speed self-avoiding walks on graphs with more than one end

Abstract A self-avoiding walk (SAW) is a path on a graph that visits each vertex at most once. The mean square displacement of an n-step SAW is the expected value of the square of the distance between its ending point and starting point, where the expectation is taken with respect to the uniform measure on n-step SAWs starting from a fixed vertex. It is conjectured that the mean square displacement of an n-step SAW is asymptotically n 2 ν , where ν is a constant. Computing the exact values of the exponent ν on various graphs has been a challenging problem in mathematical and scientific research for long. In this paper we show that on any locally finite Cayley graph of an infinite, finitely-generated group with more than two ends, the number of SAWs whose end-to-end distances are linear in lengths has the same exponential growth rate as the number of all the SAWs. We also prove that for any infinite, finitely-generated group with more than one end, there exists a locally finite Cayley graph on which SAWs have positive speed - this implies that the mean square displacement exponent ν = 1 on such graphs. These results are obtained by proving more general theorems for SAWs on quasi-transitive graphs with more than one end, which make use of a variation of Kesten's pattern theorem in a surprising way, as well as the Stalling's splitting theorem. Applications include proving that SAWs have positive speed on the square grid in an infinite cylinder, and on the infinite free product graph of two connected, quasi-transitive graphs.
Valuable Intersections: Why CSR Requires Mindfulness for Higher Ed Leaders

While academic leaders are under pressure to expand partnerships and acquisition of financial support, a main area of partnering has become companies. Corporate social responsibility (CSR) is a powerful interface that the business world provides to higher education for vital resources if planned and managed well with appropriate mutual goals. Mindful leadership is valuable to plan, orchestrate, and reflect on actions including those relating to inter-organizational behavior, which is highly visible. To be successful, higher education leaders need to utilize mindfulness to manage and leverage win–win relationships.
Interaction of SO2 and CO with the Ti2O3(101-bar2) surface.

The interaction of sulfur dioxide with the nearly perfect (101\ifmmode\bar\else\textasciimacron\fi{}2) surface of the corundum transition-metal oxide ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$ has been studied using ultraviolet and x-ray photoemission spectroscopies and low-energy electron diffraction. The reaction of ${\mathrm{SO}}_{2}$ with ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$ is found to be extremely vigorous, with ${\mathrm{SO}}_{2}$ adsorbing dissociatively and catalyzing the complete oxidation of the surface to ${\mathrm{TiO}}_{2}$ and ${\mathrm{TiS}}_{2}$. This result is significant since exposure to large amounts of ${\mathrm{O}}_{2}$ does not result in the production of large amounts of ${\mathrm{TiO}}_{2}$ at the ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$ surface. Dissociative adsorption of ${\mathrm{SO}}_{2}$ continues for exposures up to at least ${10}^{4}$ L (1 L${=10}^{\mathrm{\ensuremath{-}}6}$Torr sec). The reaction is accompanied by large scale surface disorder and by an increase in the work function of 1.32 eV. In contrast, CO adsorbs molecularly for exposures \ensuremath{\ge}${10}^{5}$ L, with an extramolecular relaxation-polarization shift of 3.0 eV. For CO exposures \ensuremath{\le}${10}^{4}$ L, the chemisorption mechanism is tentatively identified as dissociative adsorption at defect sites. Inclusive of this study, the interaction of four oxygen-containing molecules (${\mathrm{SO}}_{2}$, CO, ${\mathrm{H}}_{2}$O, and ${\mathrm{O}}_{2}$) with ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$(101\ifmmode\bar\else\textasciimacron\fi{}2) surfaces has been studied, and their behavior is compared and trends isolated with a view to understanding the oxidation of ${\mathrm{Ti}}_{2}$${\mathrm{O}}_{3}$.
Increased risk for COVID-19 in patients with vitamin D deficiency.

OBJECTIVE: The 2019 coronavirus disease (COVID-19) pandemic has disproportionally affected a variety of patients with underlying risk factors such as respiratory and cardiovascular diseases, diabetes, obesity, and black race. Vitamin D deficiency, which can result in a compromised immune response, has been also linked to increased risk and increased morbidities associated with COVID-19. In the absence of large-scale longitudinal studies to determine the strength of association between vitamin deficiency and COVID-19, cross-sectional studies of large patient cohorts can be used. METHODS: We used the i2b2 patient's registry platform at the University of Florida Health Center to generate a count of patients using the international classification of diseases (ICD)-10 diagnosis codes for the period of October 1, 2015, through June 30, 2020. Logistic regression of the aggregates was used for the analysis. RESULTS: Patients with vitamin D deficiency were 4.6 times more likely to be positive for COVID-19 (indicated by the ICD-10 diagnostic code COVID19) than patients with no deficiency (P < 0.001). The association decreased slightly after adjusting for sex (odds ratio [OR] = 4.58; P < 0.001) and malabsorption (OR = 4.46; P < 0.001), respectively. The association decreased significantly but remained robust (P < 0.001) after adjusting for race (OR = 3.76; P < 0.001), periodontal disease status (OR = 3.64; P < 0.001), diabetes (OR = 3.28; P < 0.001), and obesity (OR = 2.27; P < 0.001), respectively. In addition, patients with vitamin D deficiency were 5 times more likely to be infected with COVID-19 than patients with no deficiency after adjusting for age groups (OR = 5.155; P < 0.001). CONCLUSIONS: Vitamin D deficiency is significantly associated with increased risk for COVID-19.
An Active Steering Hand-Held Robotic System for Minimally Invasive Orthopaedic Surgery Using a Continuum Manipulator

This letter presents the development and experimental evaluation of an active steering hand-held robotic system for milling and curved drilling in minimally invasive orthopaedic interventions. The system comprises a cable-driven continuum dexterous manipulator (CDM), an actuation unit with a handpiece, and a flexible, rotary cutting tool. Compared to conventional rigid drills, the proposed system enhances dexterity and reach in confined spaces in surgery, while providing direct control to the surgeon with sufficient stability while cutting/milling hard tissue. Of note, for cases that require precise motion, the system is able to be mounted on a positioning robot for additional controllability. A proportional-derivative (PD) controller for regulating drive cable tension is proposed for the stable steering of the CDM during cutting operations. The robotic system is characterized and tested with various tool rotational speeds and cable tensions, demonstrating successful cutting of three-dimensional and curvilinear tool paths in simulated cancellous bone and bone phantom. Material removal rates (MRRs) of up to 571 mm3/s are achieved for stable cutting, demonstrating great improvement over previous related works.
The Failure of U.S. Loanable Funds to Grow as Much as Federal Reserve Securities Purchases During QE: The Role of Foreign Banks

This chapter shows that FR purchases of securities are not always matched by an equal increase in loanable funds in U.S. banks; it is often less. The best explanation for this is that the FR buys substantial amounts of securities from foreign banks, increasing the loanable funds available in foreign countries, but not increasing loanable funds in the U.S.
Steering Query Optimizers: A Practical Take on Big Data Workloads

In recent years, there has been tremendous interest in research that applies machine learning to database systems. Being one of the most complex components of a DBMS, query optimizers could benefit from adaptive policies that are learned systematically from the data and the query workload. Recent research has brought up novel ideas towards a learned query optimizer, however these ideas have not been evaluated on a commercial query processor or on large scale, real-world workloads. In this paper, we take the approach used by Marcus et al. in Bao and adapt it to SCOPE, a big data system used internally at Microsoft. Along the way, we solve multiple new challenges: we define how optimizer rules affect final query plans by introducing the concept of a rule signature, we devise a pipeline computing interesting rule configurations for recurring jobs, and we define a new learning problem allowing us to apply such interesting rule configurations to previously unseen jobs. We evaluate the efficacy of the approach on production workloads that include 150K daily jobs. Our results show that alternative rule configurations can generate plans with lower costs, and this can translate to runtime latency savings of 7-30% on average and up to 90% for a non trivial subset of the workload.
Critical review and future prospects for desiccant coated heat exchangers: Materials, design, and manufacturing

Abstract Solid desiccant dehumidification is a promising alternative to vapor compression-based air-dehumidification to reduce energy consumption and improve air quality. Desiccant coated heat exchanger (DCHE), as one type of solid desiccant dehumidification system, can improve system performance and efficiency. The thermal performance and moisture removal capability of the DCHE greatly influence its dehumidification performance. The present work aims to critically analyze the designs, materials, and manufacturing methods of heat exchangers used for solid desiccant coating and look into recent developments in regular heat exchangers, potentially deployed as a substrate for DCHE applications. A comprehensive literature review of publications regarding solid desiccant materials, heat exchangers, manufacturing and coating methods, binder materials, and the performance of heat exchangers has been developed. Alternative heat exchangers are described as better options than fin and tube heat exchangers that have been considered thus far for DCHE applications. Additionally, the heat exchanger's manufacturing process and materials over their thermal and mass exchange performance have been analyzed. Despite the widespread use of fin and tube heat exchangers for solid desiccant coating, recent developments in heat exchanger design, and related fields such as manufacturing methods and materials, open the possibilities for their application in solid desiccant dehumidification systems. Finally, the authors provide their outlook on possible developments of DCHE technology, aiming to increase systems' energy and dehumidification performance.
Design of bioactive peptides based on antibody hypervariable region structures. Development of conformationally constrained and dimeric peptides with enhanced affinity.

The variable regions of antibody molecules bind antigens with high affinity and specificity. This binding is imparted largely by the hypervariable portions of the variable region. Hypervariable regions typically fold into reverse turn or loop structures. Peptides derived from antibody hypervariable region sequences can bind antigens with similar specificity, albeit with markedly lower affinity. In this study, cyclic and dimeric peptide analogs of an anti-idiotypic/antireceptor antibody hypervariable region were developed. This antibody (87.92.6) binds to reovirus type 3 receptors on cells as well as to a neutralizing anti-reovirus type 3 monoclonal antibody (9B.G5). The cyclic peptides were utilized to probe the optimal conformation for binding to both the receptor and 9B.G5. By dimerizing or constraining the conformation of these peptides, higher affinity binding was produced. By utilizing several different cyclic peptides, the optimal conformation for binding was established. The conformationally optimized cyclic peptide possessed greater than 40-fold higher affinity for the receptor and the idiotype than the linear analog. This study suggests that conformationally constrained and dimeric peptides derived from antibody hypervariable loop sequences can bind antigens (including receptors) with reasonable affinity. hypervariable loop sequences can bind antigens (including
Prediction of runoff and soil moistures at the watershed scale: Effects of model complexity and parameter assignment

[1] The application of physically based hydrologic models implies they properly simulate processes at the computational scale. A chief criticism is that model predictions are compared only to discharge data. The physically based, hydrologic model CASC2D is reformulated such that soil moistures and fluxes can be computed using Richards' equation. The gridded surface subsurface hydrologic analysis (GSSHA) model is calibrated and verified against outlet discharge measurements during the growing season. The verified model is used to simulate an extended period during which measurements of soil moisture are available. Though soil moisture data are not used in the calibration and verification efforts, the model reproduces both the trends and the magnitude of soil moisture during the growing season. With additional formulation enhancements, soil moistures during the nongrowing season are also reproduced within a root-mean-square error of 0.1. However, more work is needed to understand the underprediction of runoff during the nongrowing season.
Online bad data detection using kernel density estimation

This paper addresses the problem of bad data detection in the power grid. An online probability density based technique is presented to identify bad measurements within a sensor data stream in a decentralized manner using only the data from the neighboring buses and a one-hop communication system. Analyzing the spatial and temporal dependency between the measurements, the proposed algorithm identifies the bad data. The algorithm was then tested on the IEEE 14-bus test system where it demonstrated superior performance detecting critical and multiple bad data compared to the largest normalized residual test.
Performance on a test of rapid stepping in community-dwelling older adults: validity, relative and absolute reliability and minimum detectable change

AbstractReduced stepping speed is associated with balance deficits and falls in older adults. We evaluated psychometric properties of a test of rapid stepping, the Thirty-Rapid-Step test (30-RST) in 37 community-dwelling older adults. Participants performed the 30-RST, dynamic (step execution time, five-times-sit-to-stand test, gait speed, maximum step length and four-square-step test) and static (single-leg-stance-time and postural sway) performance-based tests. Relationships between 30-RST and performance-based tests were evaluated with Spearman's rho. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), 95% limits of agreement and minimum detectable change at the 95% confidence level (MDC95) were computed for the 30-RST. Relationships between 30-RST and dynamic measures were moderate to very good (r = −0.35–0.73, p 0.05). The ICC2,1 was 0.85 for 30-RST indicating excellent test–rete...
Downlink resource scheduling technique for maximized throughput with improved fairness and reduced BLER in LTE

This paper proposes a downlink resource scheduling technique for maximized throughput with reduced Block Error Ratio and improved fairness among different users across the cellular region. Resources are allocated to users on the basis of Channel Quality Indicator feedback values in a way that the data rates are increased without compromising on Block Error Ratio and fairness. Channel Quality Indicator feedback values provide critical information about the channel, which enables the scheduler to perform radio resource management functions in the downlink. Simulations are performed on a link level simulator for different scenarios. Results of simulations have been demonstrated, thoroughly explained and compared with the existing scheduling techniques designed for high data rates with and without fairness.
La deformación craneana en San Pedro de Atacama

La poblacion prehistorica de San Pedro de Atacama (norte de Chile) interactuo con grupos extranjeros y socios locales de intercambio y presencio cambios demograficos en su territorio. Una de las consecuencias de estos es la visible y deliberada modificacion de la forma de la cabeza, siendo su forma el modo de inscribir las caracteristicas culturales en el cuerpo humano. El analisis de 659 craneos provenientes de 13 cementerios (300 AC-1500 DC), ocupados durante transformaciones significativas en el ambiente social, revelo el uso de este visible simbolo como instrumento para afiliarse a grupos foraneos, y durante periodos de trastorno, para consolidar la identidad del grupo. Palabras clave : deformacion craneana ; bioarqueologia ; San Pedro de Atacama. Abstract The prehistoric population of San Pedro de Atacama (Northern Chile) interacted with foreign powers and local exchange partners andwitnessed substantial demographic shifts in their area. One of the many ways they responded to these changes was through the deliberate modification of head shape; thereby inscribing cultural features on the body. This examination of 659 crania from 13 cemeteries (300 BC to AD 1500) occupied during significant transformations in the social environment revealed the use of this visible symbol to affiliate with foreign powers and, during periods of upheaval, to consolidate group identity. Palabras clave : cranial vault modification ; bioarchaeology ; San Pedro de Atacama.
Androgenic regulation of tubulin gene expression in axotomized hamster facial motoneurons

We have previously demonstrated that systemic administration of testosterone increases the rate of axonal regeneration following facial nerve crush in adult male hamsters. In this investigation, the molecular mechanisms by which androgens may enhance axonal regeneration were examined. Specifically, the following question was addressed using Northern blot and in situ hybridization with three cytoskeletal cDNA probes complementary to beta II-, beta III-, and alpha 1-tubulin mRNA: does exogenous testosterone augment axotomy-induced changes in tubulin mRNA expression in hamster facial motoneurons (FMN)? Adult male hamsters were subjected to unilateral facial nerve severance, with the opposite side serving as an internal control. One-half of the animals were subcutaneously implanted with Silastic capsules containing crystalline testosterone propionate and the other half implanted with blank capsules. Postoperative survival times were 2 and 7 d. At 2 d after axotomy alone, no changes in levels of any of the three tubulin mRNAs were observed in the injured FMN. However, by 7 d after axotomy, significant increases in all three tubulin mRNAs were observed. This time course of axotomy-induced changes in tubulin gene expression is consistent with findings in other injured neuronal populations. Administration of testosterone at the time of injury had two major effects on the cytoskeletal response pattern in axotomized FMN. First, testosterone differentially regulated the set of tubulin mRNAs examined, in that beta II-tubulin mRNA levels were selectively altered by the steroid, whereas beta III- or alpha 1-tubulin mRNAs were not.(ABSTRACT TRUNCATED AT 250 WORDS)
Predictive control for balancing wind generation variability using run-of-river power plants

In many countries, hydro power plays an important role in the electric power generation. While its fast ramping capabilities make it a perfect source to overcome the variability and intermittency of electric energy sources such as wind and solar power, constraints imposed to reduce the environmental impacts of hydro power plants also reduce its operational flexibility. In this paper, Model Predictive Control (MPC) is employed to optimally schedule the available hydro power from cascaded river power plants while complying with the imposed constraints. A model of the river dynamics derived from the Saint Venant equations is used to predict the influence of the changes in turbine discharge on water levels and discharges along the river. The objective is to reduce the variability of wind generation and at the same time also to minimize the environmental impact of river power plants by minimizing water level and discharge variations.
Editorial message: special track on applications of spatial simulation of discrete entities

Many important phenomena result from localized interactions including: population dynamics and epidemics, cell and tissue modeling, mobile computing and wireless networks. Modeling these systems can reduce experimentation costs or enable non-destructive in silica experimentation.Simulation models can be classified depending on how they represent reality, in particular time, space and simulated entities (objects). The simplest to described are models based on ordinary differential equations, which are aspatial and they may have either single time step for all objects, making time synchronous, or different time steps for different entities, making time asynchronous. Simulation entities are also described by a set of read valued parameters, so they are treated as continuous. It is well known that spatially explicit models can exhibit qualitatively different results than their aspatial counterparts [5]. This makes the models based on partial differential equations very common and popular. In this track however, we focus on a different category of models. To make this difference clear, we start with the following categorization of all models based on how they treat the three orthogonal aspects of simulations: simulation objects (entities) and the world that they inhabit (time and space). The categorization is shown in Table 1.The field of numerical computing is well studied, with numerous forums for extensive work and publication of spatial models using continuous time and treating entities as continuous (e.g. diffusion models [3, 1] or finite element method approaches [6, 11]. Traditionally, techniques for spatial modeling of discrete systems have tended to be published in application specific forums. In forming this track, we hoped to provide a unique forum for researchers in this area to come together and discuss various applications and approaches to spatial modeling.
Arthroscopically Assisted Meniscal Allograft Transplantation

Meniscal allograft transplantation (MAT) is performed in the United States in ever-increasing numbers. Various techniques have been described since the initial transplantation was performed more then 20 years ago. Decreased pain and improved knee function are attainable with proper patient selection, identification, and correction of all concomitant malalignment and instability, and intervention earlier in the disease process. This article reviews the indications for MAT and offers a basic treatment algorithm for managing concomitant cartilage lesions, instability, and misalignment. The author’s preferred arthroscopic technique using individual bone plugs for both medial and lateral MAT and fresh-frozen allograft is described. This technique stresses the low morbidity of the approach and the re-establishment of the anatomic bony attachments of the anterior and posterior horns of the meniscus.
Quantum Hall effect and anomalous transport in (TMTSF)2PF6

Under low temperatures and high magnetic fields, quasi-one dimensional organic conductor (TMTSF) 2 PF 6 exhibits a series of transitions to field-induced spin density wave (FISDW). Slightly above the onset of superconductivity in (TMTSF) 2 PF 6 , we observe a series of intervening phases that interrupt the sequence of FISDW that gives rise to the quantum Hall effect. These phases can be identified either as negative quantum numbered FISDW states or a puzzling arboresecent phase. Detailed study of the QHE in (TMTSF) 2 PF 6 reveals that the transport in the FISDW phases is dominated by anomalous longitudinal resistivities pzz and pyy that remain finite at low temperatures. While the quantization of σxy is not adversely affected at high magnetic fields, the transport in the intermediate magnetic field remains complicated. In addition, the conductivity along applied magnetic field, σ zz , cannot be easily understood in terms of three-dimensional QHE and is suggestive of the importance of inter-layer coupling.
An improved radiochemical assay for benzo(a)pyrene monooxygenase.

Abstract An improved assay for the determination of benzo[ a ]pyrene monooxygenase is described. This radiometric assay is a modification of the assay of DePierre, J. W., Moron, M. S., Johannesen, K. A. M., and Ernster, L. [(1975) Anal. Biochem. 63, 470] and uses trifluoroacetic acid to convert arene oxides which have been extracted into the hexane phase into phenols. These phenols are then extracted into the basic (product) phase. This assay method gives results comparable to those obtained by high-pressure liquid chromatography under a wide variety of conditions and, therefore, is generally applicable to the determination of benzo[ a ]pyrene monooxygenase, especially in the absence of arene oxide hydrase or in the presence of arene oxide hydrase inhibitors.
Fast in situ copolymerization of PET/PEN blends by ultrasonically-aided extrusion

Abstract An ultrasonically-aided extrusion process was developed for fast in situ compatibilization of immiscible polymer blends. PET, PEN, and their 50/50 blend were ultrasonically extruded at various amplitudes. PET underwent homopolymerization and degradation, respectively, at ultrasonic amplitudes of 7.5 and 10 μm, while PEN underwent degradation at amplitudes of 5, 7.5, and 10 μm. MALDI-TOF mass spectrometry revealed greater amounts of hydroxyl and carboxyl terminated oligomers in ultrasonically treated PET and PEN, indicating their greater reactivity. Ultrasonic treatment at short residence time led to the enhancement of transesterification reaction in the PEN/PET blend, as shown by 1H NMR and MALDI-TOF, indicating greater randomization with ultrasonic treatment. The latter was also observed through a shift in Tg that closely follows Gibbs–DiMarzio relation and an increase in viscosity of blend with treatment at an amplitude of 10 μm. No crystallinity was observed in the blend due to the already high level of transesterification introduced by extrusion without treatment. Accordingly, crystallinity, mechanical properties, oxygen permeability, and optical clarity of the blend were not influenced by ultrasonic treatment.
Inherent length-scales of periodic solar wind number density structures

[1] We present an analysis of the radial length-scales of periodic solar wind number density structures. We converted 11 years (1995–2005) of solar wind number density data into radial length series segments and Fourier analyzed them to identify all spectral peaks with radial wavelengths between 72 (116) and 900 (900) Mm for slow (fast) wind intervals. Our window length for the spectral analysis was 9072 Mm, approximately equivalent to 7 (4) h of data for the slow (fast) solar wind. We required that spectral peaks pass both an amplitude test and a harmonic F-test at the 95% confidence level simultaneously. From the occurrence distributions of these spectral peaks for slow and fast wind, we find that periodic number density structures occur more often at certain radial length-scales than at others, and are consistently observed within each speed range over most of the 11-year interval. For the slow wind, those length-scales are L ∼ 73, 120, 136, and 180 Mm. For the fast wind, those length-scales are L ∼ 187, 270 and 400 Mm. The results argue for the existence of inherent radial length-scales in the solar wind number density.
Pre-Andean orogenesis in the Coast Ranges of central Chile

An intense structural-metamorphic event of probable Permian-Triassic age is inferred from petrologic and field observations of low-grade schists from the Coast Ranges of central Chile between latitudes 38°S and 43°S. Relict almandine-rich garnet, biotite, and aluminous amphibole in mafic schists are replaced by a pervasive assemblage consisting of albite + chlorite + epidote + actinolite + sphene ± quartz: ± stilpnomelane ± white mica ± iron oxide. Chemographic analysis of phase compatibilities based on electron microprobe analyses suggests a regional retrogradation from earlier upper greenschist and/or epidote amphibolite to lower greenschist facies. A regional northwest-southeast-trending fabric within the terrane was imposed during the lower greenschist metamorphism which involved widespread reintroduction of fluids into the system. This major orogenic event is thought to be the culminating episode in a subduction-related accretionary process along the late Paleozoic margin of South America. Convergence may have been markedly oblique to the present north-south-trending continental margin.
Vibrational Displacement and Mode‐Shape Measurement by a Laser Interferometer

Four experimental methods are described in a tutorial way for use with a laser interferometer in measuring vibrational displacements and mode shapes of a transducer face. The relative merits and experimental difficulties of the methods are discussed. Quantitative data to show the type of experimental agreement that one might expect between the various methods and two illustrative mode shape measurements are given. In general, by proper choice of one or more of the methods, displacement measurements of magnitude 0.1–6000 A at sonic and ultrasonic frequencies can be made at a point 0.1 mm in diameter. Mode shapes are determined simply by moving the laser beam a measured distance between points. Displacement data presented show a random error for all methods of 5% in the range 0.5–80 A and less than 5% above 80 A.
The intrathecal lidocaine enigma: On the brink of cauda equinopathy

HE 1990s have not been kind to spinal anesthesia, the introduction, via lumbar puncture, of local anesthetic into spinal fluid. The first of many tremors to come rumbled from over a dozen instances of persistent cauda equina syndrome following continuous catheter spinal anesthesia (mostly with hyperbaric 5% lidocaine). No sooner had the microbore catheter issue been resolved when "heavy xylocaine" itself was snared in controversy over alleged neurotoxicity. Aftershocks from that eruption fanned out when neurotoxicity was implied not only for 5%, but also for 2.5% and even plain 2% lidocaine. As if that weren't enough, yet another tremor hit home when other local anesthetics (bupivacaine, mepivacaine, and even tetracaine) too became implicated in neurotoxicity, although lidocaine still tops the list. With so many reports of radicular "irritation," venting one after another in short order, dawned a growing professional concern over the imputed radiculotoxicity of local anesthetics as a pharmacologic species. Ever since the seminal 1954 report by Dripps and Vandam? intrathecal injection of local anesthetics was considered both safe and efficacious, and lidocaine specifically so in the epochal 1969 multicenter study by Phillips et al.2 One cannot help but wonder what, if anything, has changed about spinal anesthesia in the intervening decades. Did the old masters, in searching out major neurologic complications perhaps overlook or shortchange the minor transient sequelae? Has our practice changed with new techniques, better drugs, and sharper tools for detecting borderline events? Or are we simply paranoid, hyping minor postoperative backache into a major media frenzy that threatens to deny future access to one of the safest and simplest methods of anesthesia? These are the fundamental issues that will be considered in this review.
Frequency response of single and multi stage transistor amplifiers—a simple method of obtaining closed-form solutions

Internal feedback in transistors makes it difficult to calculate the amplifier frequency response in a closed form and the task is often performed numerically with the aid of a computer. It is the purpose of this communication to show that by careful use of the two-port y-parameter approach, closed-form solutions can be readily obtained which are easy to interpret and differ negligibly from the exact solutions. Results obtained from closed-form solutions and computer calculations on typical single and two-stage amplifiers are presented for comparison.
Study of the degradation of gelatin in paper upon aging using aqueous size-exclusion chromatography.

Abstract We studied the aging behaviour of gelatin used to size paper. Thus far, research on the aging of paper has largely ignored the sizing agent. Degradation of the protein was characterised and the impact of paper components, such as cellulose, and aluminium potassium sulphate was evaluated. Whatman No. 1 filter papers sized with two types of gelatins (A and B) were prepared as model samples. Commercially sized modern papers (Arches) were also studied in order to compare laboratory samples with real artist papers. Both types of papers were artificially aged (80 °C, 50% relative humidity for 35 and 94 days). Historic papers were included in the study in order to compare artificially aged with naturally aged gelatin. The aqueous extracts from the papers were characterised by aqueous size-exclusion chromatography (SEC) using four PL-Aquagel-OH columns and UV photodiode array detection at 220, 254 and 280 nm. Results showed that gelatin undergoes hydrolysis upon aging, type A gelatin showing a faster degradation rate than type B. The result was an increase in the lower-molar-mass fractions, under 50 000 g mol−1, and especially in a characteristic fraction with a peak molecular mass (Mp) of 14 000 g mol−1. A significant decrease in the extraction yields of α-, β- and γ-chains occurred after aging. This was attributed to crosslinking, leading to the formation of less-soluble polypeptides with very high molar mass (>800 000 g mol−1). Less than 10% alum had no impact on the degradation rate; higher alum contents accelerated hydrolysis reactions.
Infrared radiative decay in complex molecules

Abstract The rates of radiative internal energy dissipation have been calculated for toluene and cis -2-butene over the temperature range from 300 to 1500°K. The radiative lifetimes are of the order of seconds and decrease with increasing temperature. Radiation is probably an important mechanism of ion thermalization in trapped-ion photodissociation experiments.
Yb:S-FAP Lasers

It has recently been reported that several high power, diode-pumped laser systems have been developed based on crystals of Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F]. The Mercury Laser, at Lawrence Livermore National Laboratory, is the most prominent system using Yb:S-FAP and is currently producing 23J at 5 Hz in a 15 nsec pulse, based on partial activation of the system. In addition, a regenerative amplifier is being developed at Waseda University in Japan and has produced greater than 12 mJ with high beam quality at 50Hz repetition rate. Q-peak has demonstrated 16 mJ of maximum energy/output pulse in a multi-pass, diode side-pumped amplifier and ELSA in France is implementing Yb:S-FAP in a 985 nm pump for an EDFA, producing 250 mW. Growth of high optical quality crystals of Yb:S-FAP is a challenge due to multiple crystalline defects. However, at this time, a growth process has been developed to produce high quality 3.5 cm diameter Yb:S-FAP crystals and a process is under development for producing 6.5 cm diameter crystals.
The Effect of Real Exchange Rate Uncertainty on Exports: Empirical Evidence

Unless very specific assumptions are made, theory alone cannot determine the sign of the relation between real exchange rate uncertainty and exports. On the one hand, convexity of the profit function with respect to prices implies that an increase in price uncertainty raises the expected returns in the export sector. On the other, potential asymmetries in the cost of adjusting factors of production (for example, investment irreversibility) and risk aversion tend to make the uncertainty-exports relation negative. This article examines these issues using a simple risk-aversion model. Export equations allowing for uncertainty are then estimated for six developing countries. Contrary to the ambiguity of the theory, the empirical relation is strongly negative. Estimates indicate that a 5 percent increase in the annual standard deviation of the real exchange rate can reduce exports by 2 to 30 percent in the short run. These effects are substantially magnified in the long run.
Limit of detection determination for censored samples

Abstract The problem of setting the limit of detection is considered for censored samples and heterogeneous errors. After formal definitions of the critical level and of the method detection limit, we obtain simplified maximum likelihood-type estimators. The estimation problem of the truncation parameter and its uncertainty are reviewed. Upper confidence bounds for the limit of detection are derived and some simulation results are given.
Heat-resistant insulation systems for motors

The thermal stability of a new magnet wire known as Alkanex? wire has been evaluated as a component of heat-resistant motor insulation by four different test methods. Alkanex wire has been shown to possess approximately a 40 degrees centigrade (C) superiority in thermal stability as compared to Formex ® wire when used with suitable varnish systems. It is important to choose varnish and solvent systems which are compatible with the wire enamel. It is concluded by test that Alkanex wire can be used in equipment operating at class B temperature and that use need not await confirmation by long service trials.
Pitch strength of regular-interval click trains with different length ``runs'' of regular intervals

Click trains were generated with first- and second-order statistics following Kaernbach and Demany [J. Acoust. Soc. Am. 104, 2298–2306 (1998)]. First-order intervals are between successive clicks, while second-order intervals are those between every other click. Click trains were generated with a repeating alternation of fixed and random intervals which produce a pitch at the reciprocal of the duration of the fixed interval. The intervals were then randomly shuffled and compared to the unshuffled, alternating click trains in pitch-strength comparison experiments. In almost all comparisons for the first-order interval stimuli, the shuffled-interval click trains had a stronger pitch strength than the unshuffled-interval click trains. The shuffled-interval click trains only produced stronger pitches for second-order interval stimuli when the click trains were unfiltered. Several experimental conditions and an analysis of runs of regular and random intervals in these click trains suggest that the auditory system is sensitive to runs of regular intervals in a stimulus that contains a mix of regular and random intervals. These results indicate that fine-structure regularity plays a more important role in pitch perception than randomness, and that the long-term autocorrelation function or spectra of these click trains are not good predictors of pitch strength.
Tensile and fracture toughness properties of MA957: implications to the development of nanocomposited ferritic alloys

A study to explore approaches to optimizing nanocomposited ferritic alloys was carried out on dispersion strengthened mechanically alloyed (MA) MA957, in the form of extruded bar stock. Previous studies had indicated that this alloy manifested superior high temperature strength and radiation stability, but was extremely brittle in notch impact tests. Thus our objective was to develop a combination of tensile, fracture toughness and microstructural data to clarify the basis for this brittle behavior. To this end, tensile properties and fracture toughness were characterized as a function of temperature in various orientations relative to the grain and inclusion structures. This database along with extensive fractography suggests that brittleness is due to the presence of a large volume fraction of impurity alumina stringers. In orientations where the effects of the stringers are reduced, much higher toughness was observed. These results provide a path for alloy development approach to achieve high strength and toughness.
Assessing the program environment: Implications for program evaluation and design

Information about program environments can help to measure program quality, monitor program implementation, and identify connections between program processes and client outcomes.
Privacy constraint processing in a privacy-enhanced database management system

This paper views the privacy problem as a form of inference problem. It first provides an overview of the privacy problem and then introduces the notion of privacy constraints. Next it describes architecture for a privacy-enhanced database management system and discusses algorithms for privacy constraint processing. A note on privacy constraints processing and release control are given next. Finally some directions for future research on privacy are stated.
Some pharmacological properties of phenyl alpha-naphthyl ketimine.

Phenyl alpha‐naphthyl ketimine hydrochloride has been prepared and studied for anticonvulsant and certain other pharmacological properties. Definite anticonvulsant activity was shown against both Metrazol® and electric shock‐induced convulsions. A positive local anesthetic, hypotensive and antipyretic effect was observed but analgesic, autonomic, and irritant activities were essentially negative. Symptoms of toxicity did not occur with either single doses or with prolonged administration.
Expression of a catalytically active human cytochrome P-4502E1 in Escherichia coli

The cDNA coding for human cytochrome P-4502E1 has been expressed in Escherichia coli by placing it under the control of the isopropylthiogalactoside inducible trc promoter. Production of P4502E1 was demonstrated by immunoblots and by catalytic activity with dimethylnitrosamine as substrate. Modifications which favor expression in E. coli were made within the first seven codons. This resulted in approx. a 2- to 2.5-fold increase in P4502E1 isolated from the bacterial membranes as detected by immunoblots and catalytic activity. CO-reduced difference spectra of the modified P4502E1 revealed a peak at 452 nm, which is characteristic of hepatic P4502E1, and a molecular weight of 54 kDa. A partially purified preparation of recombinant P450 protein was active with dimethylnitrosamine, a substrate specific for this isozyme, when reconstituted with purified rat liver NADPH-cytochrome P-450 oxidoreductase. This activity was enhanced in the presence of cytochrome b5 and inhibited by the addition of antibody to the P4502E1 purified from pyrazole-treated rats. E. coli were capable of oxidizing p-nitrophenol when transformed with vector containing the human P4502E1 cDNA but not with vector alone. This in vivo metabolism of p-nitrophenol was increased 2-fold when the modified P4502E1 cDNA was used, which corresponds to the increase in P4502E1 content. Expression of human P4502E1 in E. coli appears to be an attractive system for producing large amounts of this isozyme, and for studies on the toxicological properties and structure-function relationship of the human P4502E1.
PCOS: a diagnostic challenge

Abstract Useful research and diagnostic criteria for PCOS arose from a conference in 1990, whereby PCOS could be defined by: (i) clinical and/or biochemical hyperandrogenism, (ii) chronic anovulation, and (iii) exclusion of related disorders. The presence of ‘polycystic ovaries' was not included in this definition, which created significant concern since many women with PCOS have polycystic ovaries on ultrasound, and conversely women with this ovarian morphology have a higher prevalence of androgen excess and insulin resistance. More recently, at an expert meeting in 2003 in Rotterdam, it was recommended that PCOS be defined when at least two of the following three features were present, after exclusion of other aetiologies: (i) oligo- or anovulation, (ii) clinical and/or biochemical hyperandrogenism, or (iii) polycystic ovaries. These newer criteria effectively create additional phenotypes of PCOS (e.g. women with hyperandrogenism and polycystic ovaries but normal ovulatory function, and women with ovulatory dysfunction and polycystic ovaries but no clinical or biochemical evidence of hyperandrogenism). It remains to be demonstrated whether these phenotypes actually represent patients with PCOS. Nonetheless, the trend towards the use of uniform diagnostic criteria in studies of PCOS will increase the comparability and potentially the value of published research.
Ethnography and the Book that was Lost

This article is a meditation on the way ethnography, as a method and form of expression, has informed a range of reflexive anthropological journeys in Spain, Mexico, and Cuba. It uses a poetic sens...
An HIV/AIDS Prophylactic vaccine is possible

One needs to think outside of the box, as one of us (Ronald B Luftig) learned from many years as a mathematician, and a biophysicist.
Visualizing water transport in roots: advanced imaging tools for an expanding field

Recent developments in the field of in vivo plant imaging have advanced the current state of the art to the point of near real-time visualization of water transport both through the soil matrix and the vascular system of plants. The application of these non-destructive methods holds great promise for addressing many of the unanswered questions related to plant hydraulics, in particular the below-ground processes at the soil-root interface. Warren et al. in this issue of Plant and Soil demonstrate the utility of neutron radiography and tomography in the study of hydraulic redistribution in the roots of Panicum virgatum and Zea mays in undisturbed soil. This new non-destructive imaging tool that can be used in pulse-chase experiments with D2O adds to the growing number of visualization techniques available to plant scientists.
The viscosity of amorphous metallic thin films

Abstract Creep and stress relaxation measurements on sputtered amorphous PdSi films show that the viscosity in these materials is similar to that of melt-quenched ribbons of similar composition: it increases linearly with time during isothermal structural relaxation, and the rate of increase as well as the isothermal activation enthalpy are similar over a wide range of temperatures and viscosities. This validates the earlier assumption that sample preparation is not a factor in the comparison of the viscosity of melt-quenched ribbons and the diffusivity in sputtered multilayers.
Talker-specific learning in amnesia: Insight into mechanisms of adaptive speech perception

A hallmark of human speech perception is the ability to comprehend speech quickly and effortlessly despite enormous variability across talkers. However, current theories of speech perception do not make specific claims about the memory mechanisms involved in this process. To examine whether declarative memory is necessary for talker-specific learning, we tested the ability of amnesic patients with severe declarative memory deficits to learn and distinguish the accents of two unfamiliar talkers by monitoring their eye-gaze as they followed spoken instructions. Analyses of the time-course of eye fixations showed that amnesic patients rapidly learned to distinguish these accents and tailored perceptual processes to the voice of each talker. These results demonstrate that declarative memory is not necessary for this ability and points to the involvement of non-declarative memory mechanisms. These results are consistent with findings that other social and accommodative behaviors are preserved in amnesia and contribute to our understanding of the interactions of multiple memory systems in the use and understanding of spoken language.