cssi/SciSciGPT-SciSciNet huggingface dataset:
Models of Labour Enforcement: Necessary Indeterminacy

Labour laws are enforced in many different ways. Sometimes public agencies enforce the laws and sometimes workers are authorized to do so. Sometimes employer/violators pay for litigation costs and sometimes not. Sometimes the sanctions for violations are set by the harm caused (such as loss of back pay) and sometimes the sanctions are fines and penalties. Sometimes agencies are the primary forums for hearing disputes and sometimes courts (Summers 1992). The consequences of these types of differences in labour enforcement are under-studied empirically. Labour enforcement theory, if anything, is even less well-studied. This is unfortunate, in part, because only a well-developed theory can help policy-makers sort through the many choices available when they are deciding how to enforce a labour statute. Moreover, a well-developed theory is necessary to guide researchers in their efforts. A theoretical model is needed to simplify the world sufficiently to permit testable hypotheses.
CHAPTER 2-3 – THEORY OF SPIN-SPIN MULTIPLICITY

Publisher Summary Electron-coupled spin–spin interactions are independent of the strength of the applied field. The process of extracting the chemical shifts of the participating nuclei and the coupling constants for the interactions among them, from the experimental spectra, is usually termed the analysis of the nuclear magnetic resonance spectra. Because the process is entirely mathematical and is based ultimately on quantum–mechanical calculations, organic chemists have either ignored the important information that can be gained or have used certain simplified procedures. This chapter discusses the protons and other nuclei of spin. The spin system is simply defined as a group of magnetic nuclei that interact among each other but do not interact with any nuclei outside the spin system. The definition of strongly and weakly coupled nuclei concerns the ratio of the chemical shift differences between the interacting nuclei to the coupling constants between them, which is the critical parameter determining the appearance of the spectrum. For the purpose of analysing spin multiplets, chemical shifts are best expressed in terms of frequency, that is, in Hz. Thus, they are dependent on the operating frequency of the spectrometer.
The Effects of Contract Mechanism Design and Risk Preferences on Biomass Supply for Ethanol Production

This study used a stated choice experimental survey to evaluate the effects of contract design mechanisms and farmers’ risk preferences in supplying biomass for ethanol production in a vertically coordinated biomass supply chain in Northern Plain of the United States. A rank-ordered logit model was used to assess the effects of price- and quantity-based contract mechanisms, risk preferences, and farm characteristics on ranking of contract preferences. Our empirical results show that, under price-based contract, farmers are likely to prefer contract that set fixed price when a contract was offered over short term, however, over the long term, farmers prefer a contract item that set formula with a floor price. Under quantity-based design mechanism, our model results illustrate that contract items that limit biomass quantity delivery requirement become less preferable even if farmers are allowed to negotiate on delivery price. In addition, farmer's risk perception factors toward engaging in marketing organization and vertically coordinated supply chains play a significant role in ranking contract preferences. [EconLit citations: D82; Q13; Q42]
Emotional and sensory profiling by children and teenagers: A case study of the check‐all‐that‐apply method on biscuits

Sensory and emotional profiling by consumers is gathering interest among scientists and companies as it could help to better understand the motives for food choice. Although children and teenagers are important food consumer groups, they are underrepresented in sensory research and little is known on how children and teenagers perform on these tasks. Therefore, this study investigates the emotional and sensory profiling of a traditional biscuit product among 122 children and teenagers (10–14 years old). The check-all-that-apply (CATA) approach has been applied for conducting the emotional and sensory profiling task using an age-appropriate protocol. Children and teenagers evaluated four different samples (market leader, store brand, small producer, and local bakery) and assessed their overall liking under three conditions: blind, expected (brand logo) and informed. Overall liking differed significantly among the samples and brand information influenced the informed liking scores. Samples were associated with different emotional profiles and sensory attributes by the children and teenagers. Practical applications This study illustrates the potential of using CATA questions for obtaining emotional connotations and sensory attributes of food products with children and teenagers. Together with the insights regarding their attitudes toward traditional food products and store brands, this could help producers when developing promotion initiatives to bring their traditional food products to a potential market of young consumers. Including both sensory and emotional measurements yield interesting insights for the product development if companies want to produce products in alignment with the brand message. Further, this study shows that branding influences not only the overall liking but also the sensory perception of the food products. Therefore, this study adds to the discussion on the need and importance of a more realistic product presentation during sensory testing.
Perspectives on Barriers to Eating Healthy Among Food Pantry Clients

Abstract Objective: To explore perspectives on barriers of eating healthy among food pantry clients. Methods: Food pantry clients participated in focus groups/interviews. Qualitative data were coded and analyzed using content analyses and grounded theory approach. Themes were then identified. Quantitative data were analyzed for frequencies and descriptives. Results: Fifty-four clients from 10 pantries participated in interviews/focus groups and completed questionnaires. Two major themes emerged: concern over obesity and other chronic diseases, and barriers to healthy eating. Several subthemes for barriers to healthy eating were identified: financial uncertainty, cost of healthy foods, lack of time, rationing food within family, lack of transportation, lack of adequate kitchen equipment, lack of nutrition knowledge and skills, and social support network. Conclusions: Issues identified above and those identified by others working with low-income populations need to be systematically addressed and incorporat...
Brief Exposure to Intermittent Hypoxia Prolongs QTc in Human Subjects, which is Abrogated with AT1a Receptor Blockade.

Patients with Obstructive Sleep Apnea (OSA) frequently succumb to sudden cardiac death (SCD). Prolongation of the QTc, possibly via intermittent hypoxia (IH) mediated activation of angiotensin II t...
Bilateral diffuse grade 5 radiation pneumonitis after intensity modulated radiation therapy for localized lung cancer.

Bilateral diffuse grade 5 radiation pneumonitis after intensity modulated radiation therapy for localized lung cancer
Abstract TMP120: Race and Sex Differences in the Trajectory of Cognitive Decline After Incident Stroke

Background and Objectives: Race and sex differences in the trajectory of survivors’ cognitive changes after stroke are uncertain. We measured changes in cognitive function associated with incident ...
Mid-wave and Long-Wave Infrared Linear Dichroism in a Hexagonal Perovskite Chalcogenide

Mid-wave infrared (IR) and long-wave IR spectral ranges are of growing interest in various applications such as thermal imaging, thermography-based remote sensing, and night vision. Materials widely used for IR photodetectors in this regime include cadmium mercury telluride alloys and nanostructures of compound semiconductor. The materials development for IR optics will drive down the cost of IR optical systems and enable larger scale deployment. Here, we report a mid-wave IR responsive material composed of earth abundant and non-toxic elements, Sr1+xTiS3. It has a highly anisotropic quasi-one-dimensional structure similar to hexagonal perovskites. We grew large, high quality single crystals and studied its anisotropic optical properties. We observed two distinct optical absorption edges at ~2.5 um and ~5 um, respectively, for linear polarizations along two principal axes. The material demonstrated strong and broadband linear dichroism spanning mid-wave IR and long-wave IR, with a dichroitic ratio of up to 22.
Anesthesia Maintenance During Open Airway Reconstruction

Airway reconstruction presents many challenges to the anesthesia team. A variety of factors must be considered when determining the anesthetic plan for these patients. One of the unique considerations in open airway surgery is the fact that the surgeon and the anesthesia provider jointly manage the airway. As such, collaboration and communication between the surgeon and anesthetist are essential. In this chapter, we will discuss preoperative, intraoperative, and postoperative considerations for sedation, pain control, and airway management.
Acute flaccid myelitis: lessons from polio.

With the eradication of poliomyelitis in the United States, the appearance of acute flaccid myelitis outbreaks has raised questions regarding their causation. Review of the epidemiology, clinical aspects, and laboratory findings of bygone cases of poliomyelitis have revealed shows important similarities with those of newer cases of acute flaccid myelitis. Many occurrences are preceded by an apparent viral illness, and a number of viruses, particularly enteroviruses A71 and D68, can be isolated from respiratory or stool specimens. Our inability to detect these viruses in cerebrospinal fluid samples from these patients does not eliminate them as etiologic agents, because poliovirus is often not detected in cerebrospinal fluid samples of patients with paralysis caused by poliomyelitis.
Fluoroscopic findings in Bouveret syndrome.

Abstract Bouveret syndrome occurs when a gallstone passes into the duodenum from a fistulous communication between the gallbladder and the duodenum. This is an uncommon cause of abdominal pain which is often diagnosed following surgery. Most imaging findings of Bouveret syndrome are limited to computed tomography. Shown here are fluoroscopic images of the upper gastrointestinal system in this uncommon disorder.
Results from Implementing Medical Checklist ‘Rounding Tool’ into Care Practices in a Large Neonatal Intensive Care Network

Setting: The Children’s Hospital of Philadelphia Newborn Care Network (CNBCN) is comprised of 11 neonatal intensive care units (NICU) located in the Philadelphia metropolitan area and central New Jersey. The nurseries vary in size from 4-46 beds with a wide range of critical care capabilities. Problem/Description: Patient clinical rounds in the NICU can be interrupted for many reasons. While such rounds are intended to optimize patient care and safety, Practitioners can still miss important actions such as medication reconciliation, discharge planning and ensuring safe practices and environments. Audit tools utilized during Clinical Rounds have been shown to be effective in guiding and reminding the Care Teams to complete certain actions. Aim: To implement a locally driven Rounding Tool System that will reduce the number of overlooked …
Clinical prognostic factors associated with outcome in renal cell cancer (RCC) patients treated with modified vaccinia ankara plus tumor-associated antigen 5T4 (MVA-5T4).

e15545 Background: Development of MVA-5T4 as an immunotherapeutic vaccine led to studies demonstrating it is safe and highly immunogenic as a monotherapy or combination (Amato 2008 Clin Cancer Res,...
COVID-19 Screening with Chest CT in Acute Stroke Imaging: A Clinical Decision Model.

Background and purpose Acute stroke patients may have undiagnosed coronavirus disease 2019 (COVID-19) infection, transmissible to medical professionals involved in their care. Our aim was to determine the value of incorporating a chest computed tomography (CT) scan during acute stroke imaging, and the factors that influence this decision. Methods We constructed a probabilistic decision tree of the value of acquiring a chest CT scan or not, expressed in quality-adjusted life months (QALM) of patients and medical professionals. The model was based on the chance of detecting infection by chest CT scan, the case fatality rates of COVID-19 infection, the risk of COVID-19 infection after exposure, the expected proportion of medical professionals exposed, and the exposure reduction derived from early disease detection. Results The decision to incorporate the chest CT scan was superior to not doing so (12.00 QALM vs 11.99 QALM, respectively), when the probability of patients having undetected COVID-19 infection is 3.5%, potentially exposing 100% of medical professionals, and if early detection reduces exposure by 50%. The risk of developing symptomatic COVID-19 infection following exposure casts uncertainty on the results, but this is offset by the potential for reducing exposure. Conclusions We identified a measurable benefit of incorporating a chest CT into the urgent imaging protocol of acute stroke patients in reducing exposure of medical professionals without appropriate precautions. The clinical impact of this benefit, however, may not be materially significant.
Approach to Hyponatremia

Hyponatremia is a common electrolyte disorder among both ambulatory and hospitalized patients. This teaching script leads the reader through a systematic approach to this problem. We discuss the appropriate rate of correction for hyponatremia. We describe how to use volume status and laboratory studies to identify the cause of hyponatremia.
Attribute-Based Encryption Scheme for Secure Multi-group Data Sharing in Cloud

Most of the organizations using the cloud-based data sharing platforms are multi-group in nature. The existing directly revocable attribute-based encryption (ABE) schemes though seem to be a good fit, but they fail to provide any effective solution for secure multi-group data sharing scenarios. To bridge this gap, we first propose Revocable ABE with Verifiable Outsourced decryption (ReVO-ABE)- a directly revocable collusion-resistant ABE scheme that allows any number of user revocation and joining without affecting the secret membership keys of the nonrevoked users. Based on ReVO-ABE, we build a Dynamic Multi-Group Secure Data Sharing scheme called DMG-SDS. For operations that are exclusive to multi-groups like group merge and split can be performed without affecting the attribute secret keys or membership keys of the nonrevoked users, which is not possible with any of the existing schemes. Our proposed scheme meets the necessary security requirements, and the performance assessment shows that it has much better performance benefits when compared with most the recent competitive schemes.
Antibiofilm activity of chitosan/epsilon-poly-L-lysine hydrogels in a porcine ex vivo skin wound polymicrobial biofilm model.

As antibiotic resistance continues to increase globally, there is an urgency for novel, non-antibiotic approaches to control chronic drug-resistant infections, particularly those associated with polymicrobial biofilm formation in chronic wounds. Also needed are clinically relevant polymicrobial biofilm models that can be utilized to assess the efficacy of innovative therapeutics against mature biofilms. We successfully developed a highly reproducible porcine ex vivo skin wound polymicrobial biofilm model using clinical isolates of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans. This ex vivo biofilm model was then used to assess the antimicrobial and antibiofilm properties of an easily fabricated chitosan hydrogel incorporating the natural antimicrobial peptide epsilon-poly-L-lysine. Antimicrobial activity was evaluated against planktonic cultures in vitro and against mature biofilms ex vivo. The antibiofilm efficiency of the hydrogels was especially pronounced against Pseudomonas aeruginosa, whose counts were reduced by 99.98% after 2 hours in vitro and by 99.94% after treatment for 24 hours when applied to 24 hour ex vivo polymicrobial wound biofilms. The activity of the hydrogels was lower against Staphylococcus aureus and ineffective against Candida albicans. Gram, Hucker-Twort staining of paraffin sections revealed balanced polymicrobial communities in mature 48 hour untreated biofilms. Treatment of 48 or 72 hour biofilms for 2 or 3 days with hydrogels that were applied within 5 hours after inoculation resulted in an impressive 96% and 97% reduction in biofilm thickness compared to untreated biofilms, respectively (P < .001). Likewise, topical gel treatment for 24 hours reduced biofilm thickness by 84% and 70%, respectively, when applied to mature biofilms at 24 and 48 hours after inoculation (P < .001). Thus, this ex vivo wound biofilm model provides a useful means to assess the efficacy of novel treatments to prevent and eradicate polymicrobial biofilms consisting of multidrug-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and Candida albicans.
Temperature and solvent-dependent photoluminescence quenching in [Ru(bpy)2(bpy-cc-AQ)]2+

I have herein investigated the solvent-dependent photoluminescence quenching mechanism of [Ru(bpy)2(bpy-cc-AQ)]2+ using variable temperature emission spectroscopies. The photophysics of this complex are dominated by an excited-state thermal equilibrium between a photoluminescent 3MLCT state and a charge-separated state that lies higher in energy relative to the 3MLCT state in low polarity solvents and approximately isoenergetic in high polarity solvents. Furthermore, an unusual photoluminescence temperature-dependence in high polarity solvents is shown to arise from competition between enthalpic factors favouring the charge-separated state and entropic factors favouring the photoluminescent 3MLCT state, analogous to the molecular light-switch effect of [Ru(bpy)2(dppz)]2+. The solvent-dependent photoluminescence quenching of [Ru(bpy)2(bpy-cc-AQ)]2+ is attributed to two key solvent-dependent factors: (1) the excited-state equilibrium position and (2) the rate of charge-recombination from the charge-separated state.
China's 11th Five-Year Plan and the Environment: Reducing so Emissions

China's rapid economic growth has been accompanied by a high level of environmental degradation. One of the major sources of health and ecosystem damages is sulfur dioxide (SO). Reducing SO emissions is a priority of China's environmental authorities, and the 11th Five-Year Plan (2006-2010) includes the target of reducing total SO emissions by 10 percent from the 2005 level. Given the rapid increase in SO emissions that is expected to occur in absence of intervention, attaining this target will require a significant effort. This article examines the two major policy measures the government is taking to achieve the SO target: a shutdown of many small, inefficient power plants and the installation of desulfurization equipment on existing and new coal-fired plants. We present results from a joint U.S.-China study that we participated in, which estimated the costs and benefits of these policies. We then estimate the economy-wide impacts of the two policies using a multisector model of the Chinese economy. We find that in the aggregate, the economic benefits of the shutdown of the small power plants are large enough to offset the costs of the desulfurization equipment, even without considering the substantial environmental benefits from the reduction of emissions of SO and other pollutants.
A Novel Non-Isolated Multi-Port DC-DC Converter for Hybrid Streetcar Application

In recent years, there has been an increasing interest in DC-DC multi-port power converters for transportation applications. Multi-port converters benefit from fewer components compared to multiple-converter architectures. As a result, higher power density and lower prices are among the main incentives for utilizing multi-port DC-DC converters in transportation sector. Moreover, fuel cell is among the permissible green energy resources that has been broadly considered for transportation applications. This paper proposes a novel multi-port converter for fuel cell-based hybrid streetcar application. Furthermore, an energy management scheme has been proposed for the presented multi-port converter to achieve the suitable modes of operation. Simulation results are provided to demonstrate the effectiveness of the proposed multi-port converter and the presented energy management scheme. Power loss analysis for this converter are provided and efficiencies of 92.7% and 95.1% for two- and single-stage modes are recorded, respectively.
Creating and Improving a “Virtual Object” Through Web-Mediated Discourse

Learning has been given a variety of definitions, some of them more illuminating than others. As it is currently defined, operationally, in many educational institutions, learning is what is assumed to have taken place between teacher input and student performance on a subsequent occasion of testing. There are two problems with this version. First, the process of learning remains mysterious and unavailable to observation; and second, it is treated as a relatively passive response to curriculum delivery, while the active role in the process is attributed to the teaching, whether through teacher lectures, textbook readings or the more novel electronic means of providing input. Furthermore, the learning and teaching is “encapsulated”, to use Engestrom’s (1991) term, for little consideration is given to the relationship between the knowledge to be acquired and the students’ past experience, or to the relevance of the knowledge for their current concerns and future intentions.
A Spatial Approach to Feature Linking

A spatial mechanism for the dynamical linking of features is proposed. Linking is achieved by a set of layers of feature-selective cells with competitive, topographic interactions between layers, and a suitable lateral interaction within layers. Analytical and simulation results are given for the simple case of an “on-center-off”-surround interaction.
Acquisition Activity of Webb‐Pomerene Member Firms, 1951–1968:

STOCKING AND WATKINS, in their book Cartels or Competition? state that "one of the greatest risks the United States incurs from the Webb-Pomerene Law is the spread of monopolistic practices from export trade to the domestic economy (1)." While not all acquisitions by firms constitute monopolistic practices, it is plausible that most merger activity has some anticompetitive effects. A recent report by the Federal Trade Commission covering the activities of Webb-Pomerene Associations in the 1958 to 1962 period (2) and an earlier (1962) study of acquisitions of the 500 largest industrial firms in 1961-by name of firm (3)-presents some evidence for testing the acquisition patterns of firms participating in export trade by means of Webb-Pomerene Association membership. The Webb-Pomerene Associations recently have also been the subject of both a Senate subcommittee Hearing (4) and of a doctoral dissertation (5). The interests of the Senate subcommittee centered around a general review of the Webb-Pomerene Law and the academic study encompassed a questionnaire survey of the 316 firms which were members of the 50 Webb-Pomerene Associations in the period 1962-1965 (6). In addition to the 1951-1961 period covered in the early part of this paper, acquisition data for a more recent 7 year period, 1962-1968, are available (7). These data which include only large acquisitions-those of $10 million or more of assets for most years-are noted where appropriate and, particularly, in the later part of this paper (8).
Aerosol Delivery of siRNA to the Lungs. Part 1: Rationale for Gene Delivery Systems

This article reviews the pulmonary route of administration, aerosol delivery devices, characterization of pulmonary drug delivery systems, and discusses the rationale for inhaled delivery of siRNA. Diseases with known protein malfunctions may be mitigated through the use of siRNA therapeutics. The inhalation route of administration provides local delivery of siRNA therapeutics for the treatment of various pulmonary diseases, however barriers to pulmonary delivery and intracellular delivery of siRNA exists. siRNA loaded nanocarriers can be used to overcome the barriers associated with the pulmonary route, such as anatomical barriers, mucociliary clearance, and alveolar macrophage clearance. Apart from naked siRNA aerosol delivery, previously studied siRNA carrier systems comprise of lipidic, polymeric, peptide, or inorganic origin. Such siRNA delivery systems formulated as aerosols can be successfully delivered via an inhaler or nebulizer to the pulmonary region. Preclinical animal investigations of inhaled siRNA therapeutics rely on intratracheal and intranasal siRNA and siRNA nanocarrier delivery. Aerosolized siRNA delivery systems may be characterized using in vitro techniques, such as dissolution test, inertial cascade impaction, delivered dose uniformity assay, laser diffraction, and laser Doppler velocimetry. The ex vivo techniques used to characterize pulmonary administered formulations include the isolated perfused lung model. In vivo techniques like gamma scintigraphy, 3D SPECT, PET, MRI, fluorescence imaging and pharmacokinetic/pharmacodynamics analysis may be used for evaluation of aerosolized siRNA delivery systems. The use of inhalable siRNA delivery systems encounters barriers to their delivery, however overcoming the barriers while formulating a safe and effective delivery system will offer unique advances to the field of inhaled medicine.
Understanding and combating the digital divide for single mother college students

Purpose – This case study examines the ways in which single mother college students experience the digital divide. It begins by identifying the primary challenges they face as they pursue a postsecondary degree in post‐welfare reform America. It also demonstrates how one program, computer access promoting retention and achievement (CAPRA), has helped bridge the digital divide for this particular student population.Design/methodology/approach – Data were drawn from a 2‐year ethnographic study that sought to examine the experiences of single mother college students in post‐welfare reform America. Research methods included in‐depth, semi‐structured interviews as well as participant observation.Findings – Single mother college students identified four primary challenges they encounter as they pursue a college degree: time constraints, child care, economics, and institutional climate. These challenges intersect with one another in ways that hinder single mother students’ access to the computing technologies th...
Developing teacher capacity to explore non-routine problems through a focus on the social semiotics of mathematics classroom discourse

This paper reports on a research project exploring the social semiotics of mathematics teaching and learning in urban middle schools. Participating teachers attended a Lesson Study Group that focused on the linguistic and diagrammatic challenges of framing and solving non-routine mathematics problems. This paper describes key social semiotic concepts explored with the teachers during the lesson study activities, focusing on the complex conjunction of the mathematics register and everyday language. We use examples from the participants’ classrooms to show the relevance of these concepts in studying classroom discourse, focusing in particular on the complex conjunction of diagramming and language.
Inner Displacements of Strained hcp Metals

The inner-displacement tensor for magnesium has been calculated by minimizing the binding energy of the strained crystal as a function of the inner displacement. The binding energy is calculated by the pseudopotential method. The pseudopotential has two parameters, which were determined by fitting the $\frac{c}{a}$ ratio and the elastic constant (${c}_{33}+\frac{1}{2}{c}_{11}+\frac{1}{2}{c}_{12}\ensuremath{-}2{c}_{13}$).
Resonances of biological cells at audible frequencies

Two theories are discussed to account for the observed resonances of biological cells at sonic frequencies. One theory assumes the cell wall to be a stretched balloon surrounded by, and filled with, an incompressible fluid. The other treats the cell wall as a rigid shell. Both lead to reasonable physical constants for the cell wall.
The minimum duration of reactivation at 6 months: latency of retrieval and reforgetting

Abstract A reactivation treatment is a priming procedure that alleviates forgetting when an organism is re-exposed to part of the original training event. Presently, we asked what is the minimum duration of an effective prime at 6 months of age and how it affects infants’ subsequent retention. Ninety-six 6-month-old infants were trained in an operant mobile or train task. In Experiments 1a and 1b, we determined that the minimum effective duration of a reactivation treatment was 7.5 s for both tasks. In subsequent experiments, we found that decreasing the duration of reactivation affected the temporal parameters of the reactivated memory. A forgotten memory that was reactivated with a 7.5-s prime took longer to retrieve (Experiments 2a and 2b) and was reforgotten more rapidly (Experiments 3a and 3b) than memories that are reactivated with a standard 120-s prime. These results reveal that memory reactivation is an incremental rather than an all-or-none phenomenon.
Commentary on: Anthropometry of the eyelid and palpebral fissure in an Indian population.

In their article “Anthropometry of the Eyelid and Palpebral Fissure in an Indian Population,” Dr. Patil et al establish normal periorbital anthropometric values for a population that has not been studied to a great degree in the oculoplastic surgery literature. Their study included 216 male and female patients, 16 to 60 years old. Digital image analysis was prospectively performed to measure the following parameters: In choosing these measurements, the authors investigated parameters consistent with ranges published in current ophthalmic plastic surgery literature.1-4 The authors found that the mean intercanthal distance increased with age in both males and females, along with an increase in the palpebral fissure width …
Maternal sociodemographic characteristics as risk factors for preterm birth in twins versus singletons.

Many studies have examined associations between sociodemographic variables and preterm birth in singletons. However, almost no research has been published on whether variables such as maternal age, race, ethnicity, level of education and smoking are associated with preterm birth among twins in the same way. The purpose of this study was to examine such associations in twins and singletons comparatively. The study population consisted of all 567796 twins and 23297909 singleton births recorded in the US birth records for 1990-95. Gestational age data were rigorously 'cleaned' to solve the problem of biologically implausible birthweight/gestation combinations in vital records. Preterm birth was defined as gestational age < 35 weeks. Some 25.8% of twins and 3.2% of singletons were preterm by this definition. Crude and adjusted relative risks (RR) were estimated using a modified Mantel-Haenszel procedure. We found several characteristics associated with preterm birth in both twins and singletons, e.g. for twins: race (black adjusted RR = 1.30 compared with white non-Hispanic); marital status (unmarried adjusted RR = 1.15 compared with married); and age (< or = 17 years adjusted RR = 1.39 compared with 20-29 years). A similar analysis of singletons revealed stronger associations between the same characteristics and preterm birth, e.g. the adjusted RR for black race was 2.3. These differences in RRs suggest that sociodemographic characteristics have weaker effects on preterm birth among twins than among singletons. Care must be taken in interpreting differences in preterm birth in twins and singletons, as their gestational age distributions differ so markedly.
Mammalian Reovirus L2 Gene and λ2 Core Spike Protein Sequences and Whole-Genome Comparisons of Reoviruses Type 1 Lang, Type 2 Jones, and Type 3 Dearing

Abstract The reovirus L2 genome segment encodes the core spike protein λ2, which mediates enzymatic reactions in 5′ capping of the viral plus-strand transcripts. Complete nucleotide-sequence determinations were made for the L2 genome segments of eight mammalian reoviruses, including the prototype isolates of serotypes 1 and 2: Lang (T1L) and Jones (T2J), respectively. Each L2 segment was found to be 3912 or 3915 bases in length. Partial nucleotide-sequence determinations were also made for the 3916-base L2 segment of reovirus type 3 Dearing (T3D), the prototype isolate of serotype 3. The whole-genome sequence of reovirus T3D was reported previously. The T1L L2 analysis represents completion of the whole-genome sequence of that isolate as well. The T2J L2 analysis leaves only the sequence of the M1 segment yet to be reported from the genome of that isolate. The T2J M1 sequence made available from analysis in another lab was used for initiating whole-genome comparisons of reoviruses T1L, T2J, and T3D in this report. The nine L2 gene sequences and deduced λ2 protein sequences were used to gain further insights into the biological variability, structure, and functions of λ2 through comparisons of the sequences and reference to the crystal structure of core-bound λ2. Phylogenetic comparisons suggest the presence of three evolutionary lines of divergent L2 alleles among the nine isolates. Localized regions of conserved amino acids in the λ2 crystal structure include active-site clefts of the RNA capping enzyme domains, sites of interactions between λ2 domains within the pentameric spike structure, and sites of interaction between λ2 subunits and other proteins in viral particles.
Emerging interactions between skin stem cells and their niches

The skin protects mammals from insults, infection and dehydration and enables thermoregulation and sensory perception. Various skin-resident cells carry out these diverse functions. Constant turnover of cells and healing upon injury necessitate multiple reservoirs of stem cells. Thus, the skin provides a model for studying interactions between stem cells and their microenvironments, or niches. Advances in genetic and imaging tools have brought new findings about the lineage relationships between skin stem cells and their progeny and about the mutual influences between skin stem cells and their niches. Such knowledge may offer novel avenues for therapeutics and regenerative medicine.
A Market-Based Control Solution for Semiactive Structural Control

A decentralized control algorithm for structural control system design has been developed. This novel approach is termed market-based control. As a potential alternative to the classical Linear Quadratic Regulator (LQR), this method decentralizes the decision process of the control system and allows for independent and autonomous control formulation to occur directly upon the control device. This paper outlines the theoretical formulation of both approaches and presents their performance on a semi-active controlled structural model.
Constructive and Constructivist Challenges for Applied Linguistics

I argue here that the most productive future directions for theory building and research in applied linguistics derive from the extent to which the field's investigators can enrich their conceptual frameworks and methods with insights from “constructivist” scholarly approaches. Such approaches are marked by heightened attention to agency and subjectivity, to the generation and interpretation of meaning, and to the constant interplay between individual and group activity. In addition, I discuss scholarship from other social sciences that further illuminates conditions affecting language learning. The presentation focuses on 3 arenas in which such approaches and additional scholarship have generated important new questions for applied linguistics: (a) the multiple identities of language users, (b) the identification of optimal environments for language acquisition, and (c) the institutional constraints affecting language acquisition and instruction. In each area, constructivist approaches challenge applied linguists to rethink the bounds of the theories andmethods that guide their work.
Application of Micro-Electrospray Liquid Chromatography Techniques to FT-ICR MS to Enable High-Sensitivity Biological Analysis

A microbore electrospray (ESI) injection system has been adapted to our 9.4-tesla ESI FT-ICR mass spectrometer, greatly enhancing the stability and sensitivity of the system. Spray was generated from micro-ESI needles made from sharply tapered, polished fused silica capillaries of 25 to 50 µm inner diameter. Micro-ESI permits low-level sample analysis by constant infusion at sub-µL/min flow rate over a wide range of solvent conditions in both positive- and negative-ion mode. The system is flexible and allows rapid conversion to allow routine LC/MS analysis on low-level mixtures presented in biological media. LC/MS analyses were accomplished by replacing micro-ESI needles with capillaries packed with reverse phase retention media to permit analyte concentration and purification prior to analysis (micro-ESI/LC). A unique nano-flow LC pumping system was developed, capable of producing a true unsplit solvent gradient at flow rates below 1 µL/min. The micro-ESI/LC FT-ICR system produces mass spectra from a mixture of three neuroactive peptides at a concentration of 500 amol/µL (5 fmol each total loaded) in biological salts with baseline separation, signal-to-noise ratio of >10:1 and mass resolving power >5000. These results represent a reduction in detection limit by a factor of ∼2 × 106 over the best previously published LC/FT-ICR MS data.
Long‐wavelength‐absorbing dialkylphenacylsulfonium salt photoinitiators: Synthesis and photoinduced cationic polymerization

A series of sulfonium salt photoinitiators with the general structure Ar′S+CH3(C12H25)SbF, where Ar′ is phenacyl (I), 2-indanonyl (II), 4-methoxyphenacyl (III), 2-naphthoylmethyl (IV), 1-anthroylmethyl (V), or 1-pyrenoylmethyl (VI), were prepared with a novel, simple one-pot process that involves the reaction of an α-bromoalkylarylketone (Ar′Br) with the dialkylsulfide (CH3SC12H25) in the presence of sodium hexafluroantimonate in 2-butanone at room temperature. The photoreactivity of photoinitiators II–VI were evaluated and compared to the unsubstituted analogue, I, in the polymerization of a variety of epoxide monomers. Real-time infrared spectroscopy and differential scanning photocalorimetry studies revealed that the indanonyl initiator II is more active than I. However, sulfonium salts IV–VI, which contain polycyclic aromatic structures, are much less effective as cationic photoinitiators. Interestingly, photoinitiator III is either more or less reactive compared to I, depending on the monomer used. Our work also showed that the efficiency of the unsubstituted phenacylsulfonium salt I can be significantly enhanced through the use of photosensitizers. Mechanistic aspects of the photopolymerization studies are discussed. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1433–1442, 2000
Convergence demands by spectacle magnifiers

A general equation, c delta = k1b + k2sF, for finding the binocular convergence demands by spectacle magnifiers to view images at any distance is presented. Factor k1 in the equation yields the accommodative demand to view the image; factor k2 determines the actual reduction in convergence demand provided by the vendors' incorporation of base-in prism. When magnifiers from virtual images at finite distances, such as at the least distance of distinct vision or 25 cm, the interpupiliary distance (b), the separation between the lenses and the eyes (d), and the distance between the optical centers of the lenses (s) are basic quantities, according to this equation. The fundamental datum that the vendors should specify is the distance (s) between the optical centers of the lenses, rather than base-in prism. The specification of base-in prism is unrellable when images are formed at finite distances and the frame PD is not equal to the distance IPD. When the image is formed at infinity, that is when the angular magnification M = F/4, the convergence demand by spectacle magnifiers only depends on the separation between the optical centers of the lenses and the lens power, that is, c delta = sF. It is independent of the interpupillary distance (b) and the separation between the lenses and the eyes (d). We also present an equation, to find the disparity of the accommodative/convergence relation caused by spectacle magnifiers. Knowing the demands on convergence and accommodation, the practitioner can probably evaluate the potential for successful adaptation to spectacle magnifiers from routine measurements of positive and negative relative convergence and accommodation.
Acoustic microscopy of curved surfaces

To date, imaging and metrology in the acoustic microscope have been performed exclusively on planar specimens. While imaging is accomplished by raster scanning in the plane transverse to the axis of the acoustic beam, metrology is practiced by variation of the specimen‐lens separation along the beam axis. This operation yields an acoutic material signature at a single location on the specimen plane. The two modes of operation are in effect simultaneously employed when a nonplanar surface of known curvature is scanned. The resulting images reveal concentric rings with radial periodic brightness variation if the surface is spherical in shape. The technique is demonstrated with stainless‐steel bearing balls of the type used in precision gyros. The application of this technique to the diagnostic inspection and analysis of both bearing balls and raceways are discussed. It is suggested that the obtained images represent a two‐dimensional map of elastic properties of the bearing surface regions.
Extraction of the photon spectra from measured beam parameters

Knowledge of the photonspectrum of a radiotherapy beam is often needed for three-dimensional (3-D) dose calculations using Monte Carlo methods and/or algorithms employing energy deposition kernels. Direct measurement of the x-ray energy fluence spectrum is not feasible for the high-energy photon beams used clinically. In this paper, the spectrum is extracted from basic beam data that are readily obtained for a clinical beam. We describe the photonspectrum using just two parameters. One parameter, which determines the high-energy part of the spectrum, is obtained using the measured dose in the buildup region for a small field, where electron contamination of the beam can be neglected. The other parameter is extracted from the photon beam attenuation in water. The results compare favorably to spectra generated from Monte Carlo simulations.
Neonatal depletion of cortical dopamine: effects on dopamine turnover and motor behavior in juvenile and adult rats

Abstract Abnormal development of mesoprefrontal dopamine (DA) neurons may contribute to the pathophysiology of schizophrenia. Consistent with this hypothesis, DA nerve terminal density is decreased in the cortex of schizophrenic subjects [M. Akil, J.N. Pierri, R.E. Whitehead, C.L. Edgar, C. Mohila, A.R. Sampson, and D.A. Lewis, Lamina-specific alterations in the dopamine innervation of the prefrontal cortex in schizophrenic subjects, Am. J. Psychiatry, 156 (1999) 1580–1589]. This abnormality may be present early in development, giving rise to dysfunction as an individual matures. The present studies examined the effects of early partial loss of medial prefrontal cortex (mPFC) DA on DA turnover and locomotor behavior in juvenile, pubertal, and adult rats (30, 45, and 60 days of age, respectively). Local infusions of 6-hydroxydopamine on postnatal day (PN) 12–14 produced persistent decreases in basal tissue DA concentrations and increases in 3,4-dihydroxyphenylacetic acid (DOPAC):DA ratios in the mPFC. In the nucleus accumbens of lesioned rats, basal DA concentrations were decreased and DOPAC:DA ratios were increased on PN30, but not PN45 or 60. Footshock (30 min at 0.6 mA) increased DOPAC and DOPAC:DA ratios in the mPFC of PN30 and 60 control rats. These effects were attenuated in age-matched rats previously sustaining ∼50% loss of mPFC DA on PN12–14. Footshock did not affect DOPAC:DA ratios in the nucleus accumbens of control or lesioned rats. The lesion also failed to alter basal or stress-evoked motor activity. The present data suggest that a decreased density of mPFC DA nerve terminals occurring early in development results in persistent alterations in basal and stress-evoked activity of mesoprefrontal DA neurons, but not mesoaccumbens DA neurons.
ON THE MULTIPLATEN Z-BUFFER ALGORITHM FOR RAY TRACING IN HIGH-FREQUENCY ELECTROMAGNETIC SCATTERING COMPUTATIONS

A ray tracer based on the multiplaten Z-buffer (MPZ) algorithm is implemented and its performance is evaluated against the binary space-partition tree algorithm. Our results indicate that the computational complexity of the MPZ is independent of the number of facets, thus making it potentially attractive for targets described by a large number of facets. A multi-aspect MPZ (MAMPZ) is also proposed to further enhance the speed performance of the MPZ algorithm. It is shown that by storing multi-aspect Z-buffers, it is possible to significantly accelerate the ray-tracing time of the MPZ. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 298–301, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20450