cssi/SciSciGPT-SciSciNet huggingface dataset:
“Tumor-like” lesions of the pediatric brain

Distinguishing “real” neoplastic tumors from “tumor-like” lesions of the central nervous system is important to treat children properly, to predict outcome and prognosis, and to avoid unnecessary medical treatment or surgical interventions. Neuroimaging plays a key role in the correct differentiation between both entities. Pediatric radiologists should be aware of all non-neoplastic lesions that may mimic tumors. High-end anatomic and advanced magnetic resonance imaging as well as the correlation with history and clinical findings facilitate differentiation between both entities. The aim of this pictorial review is to review the neuroimaging manifestations of the most common “tumor-like” lesions affecting the pediatric brain.
Promoting Father Involvement for Child and Family Health

Paternal involvement in children's lives is associated with a variety of child outcomes, including improved cognition, improved mental health, reduced obesity rates, and asthma exacerbation. Given this evidence, the American Academy of Pediatrics has promoted actions by pediatricians to engage fathers in pediatric care. Despite these recommendations, the mother-child dyad, rather than the mother-father-child triad, remains a frequent focus of care. Furthermore, pediatric care is often leveraged to improve maternal health, such as screening for maternal depression, but paternal health is infrequently addressed even as men tend to exhibit riskier behaviors, poorer primary care utilization, and lower life expectancy. Therefore, increasing efforts by pediatric clinicians to engage fathers may affect the health of both father and child. These efforts to engage fathers are informed by currently used definitions and measures of father involvement, which are discussed here. Factors described in the literature that affect father involvement are also summarized, including culture and context; interpersonal factors; logistics; knowledge and self-efficacy; and attitudes, beliefs, and incentives. Innovative ways to reach fathers both in the clinic and in other settings are currently under investigation, including use of behavior change models, motivational interviewing, mobile technologies, peer support groups, and policy advocacy efforts. These modalities show promise in effectively engaging fathers and improving family health.
Functional Symptoms in Pediatric Emergency Medicine

Common disorders that frequently present as a result of functional issues in the pediatric emergency department include chronic non-pathological pain, acute chest pain, syncope, recurrent abdominal pain, and fatigue. These complaints are often broad in nature and nonspecific, leading to potentially lengthy diagnostic evaluations that are cumbersome for both the patient and the healthcare system. This chapter describes three cases of patients presenting to the emergency department whose optimal treatment required addressing their underlying psychological issues. Incorporation of child life specialists and others trained in non-pharmacologic stress reduction can assist in alleviating the anxiety and pain associated with functional issues in such patients.
Postoperative Care of the Pancreas-Transplant Recipient

Diabetes mellitus (DM) affects about 5% of the population and represents the eighth leading cause of death in the United States.1 It is the leading cause of renal failure and blindness in adults and the most frequent, underlying disease leading to amputations.2 Whole-organ pancreas transplantation is no longer an experimental procedure but a valid therapeutic option for patients with type I DM. For patients who are dependent on exogenous insulin for survival, the objectives of pancreas transplantation include insulin independence and normoglycemia, improvement in quality of life, and amelioration of secondary complications of DM.
Transferable Atom Equivalents. Molecular Electrostatic Potentials from the Electric Multipoles of Pro Aims Atomic Basins

The ab-initio electrostatic potential fields surrounding several heteroatom-containing molecules are compared to the corresponding potential fields generated by atom-centered multipole expansions of the electron density distributions within PROAIMS-defined atomic basins. When the electron populations of a set of atomic basins are subtracted from the associated nuclear charges, the resulting “atomic charges” can be used as the monopole terms of a three-term expansion (monopole + dipole + quadrupole). The monopole terms were found to inadequately represent the atomic electron distribution when considered alone, but when the dipole and quadrupole terms are included, the molecular electrostatic potential field can be reconstructed with a high degree of accuracy. These multipolar terms were found to be transferable between molecules within defined limits. This result has allowed the construction of accurate electrostatic potential fields around molecules which are much too large for direct ab-initio treatment. These results are compared to some popular “spherical atom” approaches currently in use for approximating intermolecular electrostatic interactions.
Molecular Mechanisms Regulating Adult Stem Cell Self-Renewal

Stem cells have defining properties that are suited for tissue homeostasis and repair, but a central issue is how these cells generate mature cell types without exhausting their capacity for self-renewal. This chapter focuses on the central nervous system (CNS) to exemplify the regulation of adult stem cell self-renewal in the service of organ function. Topics will include conventional and novel methods used to distinguish stem cells from other proliferating cell types and the pitfalls in attempting to precisely characterize stem cell function. These methods reveal that stem cells interpret multiple signals to control the balance of self-renewal and quiescence. Among the emerging themes is that stem cell self-renewal is dynamically regulated throughout life, is integrally connected with lineage specification, and reflects a conservation of many intrinsic and extrinsic mechanisms from fetal development.
Problem Solving and Explanation in Intelligent Tutoring Systems: Issues for Future Research

The key to building effective intelligent tutoring systems is the representation of knowledge in the tutor’s problem solver. The problem solving knowledge determines the reasoning of students that the system can understand and the type of feedback the system can provide. We discuss the form of problem solving knowledge in intelligent tutors and the use of problem solving knowledge to provide guidance and feedback. We argue that model tracing tutors can be extended by building more underlying knowledge into their rule bases, and briefly describe GIL, a programming tutor built upon this elaborated model. We describe some of the current issues facing intelligent tutoring research, including the integration of rule-based and qualitative reasoning, timing and content of feedback, pedagogical strategies, and human- computer interface issues.
THE NON-LINEAR DYNAMICS OF THIN WALLED SHELL STRUCTURES

This paper discusses the non-linear oscillations and dynamic instabilities of thin walled shells subjected to harmonic loads. Due to the presence of strong non-linearities and high sensitivity to small variations in control parameters, thin shells may display a complex dynamic behavior and, despite the recent advances in this field, there is still a lack of satisfactory solutions to this class of problems. There are several complicated issues relating to the dynamics of such structures. In this work some of these topics are addressed, namely shell discretization processes, influence of modal coupling on non-linear vibration modes, modal interaction between different non-linear vibration modes, imperfection sensitivity and fractal basin boundaries. To this end, the theory for quasi-shallow shells is used to study the non-linear vibrations and instabilities of thin cylindrical shells under axial load.
Making Sense of Digital Game-Based Learning: A Learning Theory-Based Typology Useful for Teachers

Digital game-based learning (DGBL) has gained traction on various educational levels in recent years as educators continue to seek best practices and researchers keep conducting studies to investigate the affordances and constraints of such technology-mediated instruction. This paper discusses the intersections between the historical development of educational digital games and contemporary theories of learning. Resultant from the review, a typology of educational digital games consisting of four genres -- edutainment and educational game applications, serious games, commercial off the shelf and massive multiplayer online role-playing games, and educational game design tools--is devised to help teachers interested in digital games better understand the pedagogical processes and cope with challenges involved in implementing DGBL. The paper concludes with the importance that the implementation of different genres of educational digital games in instruction entails teachers’ usage of different pedagogical strategies in accordance with the chosen game genre and opportunities to teach subject area content.
MutLγ promotes repeat expansion in a Fragile X mouse model while EXO1 is protective.

The Fragile X-related disorders (FXDs) are Repeat Expansion Diseases resulting from an expansion of a CGG-repeat tract at the 5’ end of the FMR1 gene. The mechanism responsible for this unusual mutation is not fully understood. We have previously shown that mismatch repair (MMR) complexes, MSH2/MSH3 (MutSβ) and MSH2/MSH6 (MutSα), together with Polβ, a DNA polymerase important for base excision repair (BER), are important for expansions in a mouse model of these disorders. Here we show that MLH1/MLH3 (MutLγ), a protein complex that can act downstream of MutSβ in MMR, is also required for all germ line and somatic expansions. However, exonuclease I (EXO1), which acts downstream of MutL proteins in MMR, is not required. In fact, a null mutation in Exo1 results in more extensive germ line and somatic expansions than is seen in Exo1+/+ animals. Furthermore, mice homozygous for a point mutation (D173A) in Exo1 that eliminates its nuclease activity but retains its native conformation, shows a level of expansion that is intermediate between Exo1+/+ and Exo1-/- animals. Thus, our data suggests that expansion of the FX repeat in this mouse model occurs via a MutLγ-dependent, EXO1-independent pathway, with EXO1 protecting against expansion both in a nuclease-dependent and a nuclease-independent manner. Our data thus have implications for the expansion mechanism and add to our understanding of the genetic factors that may be modifiers of expansion risk in humans.
Learning to Decode LDPC Codes with Finite-Alphabet Message Passing

In this paper, we discuss the perspectives of utilizing deep neural networks (DNN) to decode Low-Density Parity Check (LDPC) codes. The main idea is to build a neural network to learn and optimize a conventional iterative decoder of LDPC codes. A DNN is based on Tanner graph, and the activation functions emulate message update functions in variable and check nodes. We impose a symmetry on weight matrices which makes it possible to train the DNN on a single codeword and noise realizations only. Based on the trained weights and the bias, we further quantize messages in such DNN-based decoder with 3-bit precision while maintaining no loss in error performance compared to the min-sum algorithm. We use examples to present that the DNN framework can be applied to various code lengths. The simulation results show that, the trained weights and bias make the iterative DNN decoder converge faster and thus achieve higher throughput at the cost of trivial additional decoding complexity.
RELATIONSHIP BETWEEN SOLUBLE F11 RECEPTOR, TOTAL NITRIC OXIDE LEVELS, AND VASCULAR FUNCTION IN AFRICAN AMERICANS WITH TYPE II DIABETES

Human F11 receptor (F11R) is an important cell adhesion molecule implicated in inflammatory thrombosis. F11R is associated with the presence and severity of cardiovascular disease. Endothelial dysfunction in diabetes has been attributed to lack of bioavailability of nitric oxide (NO), another key
Predicting physical activity among urban adolescent girls: A test of the health promotion model

The purpose of this study was to test hypothesized relationships of the health promotion model (HPM) as a means of predicting moderate-to-vigorous physical activity (MVPA) among urban, adolescent girls. A secondary analysis of baseline data from a group randomized controlled trial was conducted. The study involved eight urban schools in the Midwestern United States. The sample included girls (N = 517) in the 5th-8th grades. Data were collected on age, body mass index, pubertal status, enjoyment, self-efficacy, social support, options for physical activity (PA), and commitment to PA. MVPA was measured via accelerometers worn by the girls for 7 days. Structural equation modeling was used to analyze study aims. Mean age of the sample was 11.8 years (standard deviation [SD] = 1.0). Girls attained an average of 3.0 (SD = 1.2) minutes per hour of MVPA. Self-efficacy had a positive direct (β = .337; p < .001) and total effect (β = .310; p < .001) on MVPA. Social support and options for PA were not significant predictors of commitment to PA or MVPA. Commitment to PA had a negative but nonsignificant effect (β = -.056; p = .357) on MVPA. The model predicted 10.1% of the variance in MVPA with 9.6% of the variance predicted by self-efficacy. Limitations include lack of longitudinal analysis and inability to generalize the results to other populations such as boys. PA self-efficacy continues to emerge as a significant predictor of MVPA in the HPM. Continued theory testing is needed to better understand the correlates and determinants of PA among adolescent girls before designing theory-based interventions to promote PA.
Relationship satisfaction, communication self-efficacy, and chronic fatigue syndrome-related fatigue.

Abstract Rationale Relationship dissatisfaction has been linked with worse health outcomes in many patient populations, though the mechanism(s) underlying this effect are unclear. Among patients with chronic fatigue syndrome (CFS) and their partners, there is evidence for a bi-directional association between poorer relationship satisfaction and the severity of CFS-related fatigue. Objective Here, we hypothesized that relationship dissatisfaction negatively impacts fatigue severity through greater depression and less patient satisfaction about communication about symptoms to partners. Method Baseline data were drawn from diagnosed CFS patients (N = 150) participating in a trial testing the efficacy of a stress management intervention. Data derived from fatigue severity (Fatigue Symptom Index, FSI), depression (Center for Epidemiologic Survey-Depression, CES-D), relationship quality (Dyadic Adjustment Scale, DAS) and communication satisfaction (Patient Symptom Disclosure Satisfaction, PSDS) questionnaires were used for bootstrapped indirect effect analyses using parallel mediation structural equation modeling in Mplus (v8). Age and BMI were entered as covariates. Results Greater relationship satisfaction predicted greater communication satisfaction (p Conclusion Results highlight the importance of considering depression and communication-related factors when examining the effects of relationship satisfaction on CFS symptoms such as fatigue. Further mechanism-based, longitudinal research might identify relationship-related mediating variables that can be targeted therapeutically.
Legal Immigration Will Resolve America's Real Border Problems

The U.S. government has allowed its asylum and border processing system to become overwhelmed. Central Americans are crossing illegally and often relying on asylum and other processing procedures at the border because they are virtually the only ways for them to enter the United States. After numerous failed attempts to deter the flow or restrict asylum, the most realistic and humane way to control the border is for Congress and the administration to channel future immigrants into an orderly legal structure for coming to the country. Five reforms would make the asylum system manageable again and restore control over the border: 1. Humanitarian parole: Waive entry restrictions for Central Americans in the backlogged green card lines and with family legally in the United States. 2. Private refugee sponsorship: Allow U.S. residents and organizations to sponsor refugees from abroad as the State Department had planned in 2016. 3. Guest worker expansion: Expand the H-2A and H-2B seasonal worker programs to year-round jobs for Central Americans and waive the H-2B cap. 4. Legalization: Legalize illegal immigrants who have no serious criminal convictions and let them reunite with their spouses and children, eliminating the network for future illegal immigration. 5. Processing at ports: Remove the cap on asylum seekers at ports of entry, process 100 percent of their claims there, and release them with an employment authorization document contingent on them appearing in court. These reforms will not stop all asylum seekers, but they will redirect enough of the flow into other legal channels to make the asylum process manageable again for U.S. authorities.
Cognitive training in children with hypoplastic left heart syndrome: A pilot randomized trial

Abstract Neurodevelopmental disabilities are common sequelae of congenital heart disease, particularly cognitive impairments that impede academic achievement. Cognitive training has been shown to be effective in improving working memory in other patient groups. Computerized cognitive training programs may hold potential for children and adolescents with congenital heart disease, but are untested in this population. In this single-center, single-blinded, randomized controlled trial, the feasibility and efficacy of Cogmed Working Memory Training (Cogmed) was compared with observation in children with hypoplastic left heart syndrome 8 to 16 years of age. Participants were randomized to either Cogmed at home for 5 weeks with coaching by a study team member or an observation control group. Baseline, 6–8 weeks later (post-intervention), and 6-month assessments of working memory were completed. Participants randomized to the Cogmed intervention (n = 10) demonstrated greater improvement than controls (n = 10) on measures of working memory, the Wechsler Intelligence Scale for Children-V Working Memory Index and the National Institutes of Health Toolbox Cognitive Battery post-training that were statistically significant (Cohen's d = 0.76, p
Patterns of Opioid Prescribing among Medicare Advantage Beneficiaries with Pain and Cardiopulmonary Conditions

Background: Pain is common among patients with cardiopulmonary conditions; however, there are increasing concerns, but limited research, regarding use of opioids for pain in patients with noncancer...
Otologic And Neurotologic Manifestations Of Acquired Immunodeficiency Syndrome

In contrast with the ubiquitous presence of head and neck symptoms associated with human immunodeficiency (HIV) infection, acquired immunodeficiency syndrome (AIDS)-related complex (ARC), and AIDS, otologic and neurotologic manifestations are less frequent. Routine organisms predominate, and often the ear disease is not directly related to HIV infection. Kaposi’s sarcoma of the ear, Pneumocystis carinii otitis, eustachian tube obstruction due to nasopharyngeal mass, serous otitis media, auditory brain stem response abnormalities, sensorineural hearing loss secondary to central nervous system complications of AIDS, and facial nerve palsy constitute true otologic manifestations associated with HIV infection.
Using Precision Astrometry to Recover Near-Earth Object Candidates

The Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescopes, located on Haleakala, Hawaii, spend much of their time searching the sky for Near-Earth Objects (NEOs) that may represent a hazard to Earth. The cameras on each telescope have small pixels and therefore deliver excellent astrometry. Some Near-Earth Object candidates that Pan-STARRS discovers are lost, because they are not recovered on subsequent nights. Over the course of the approximately 1 hour of observations when NEOs are initially discovered, many of the NEOs seen by Pan-STARRS display a small amount of non-linear motion (or curvature) in their path through the sky. This curvature arises due to the motion of the observer, and is a helpful diagnostic tool for establishing the approximate distance to the NEO and its size. At the present time, this curvature is not being fully used to tightly constrain the predicted position of the NEO one night later, and as a result, some NEOs are not recovered. A detailed study of the astrometric precision of Pan-STARRS was undertaken, using objects for which very precise orbits are known. The precision astrometry for NEOs from Pan-STARRS from a single night, and the curvature that it displays, was then used to better constrain the likely position of NEOs one night later. The predicted positions were compared to the real positions for these objects. For some objects, there was little change in the predicted position, but for four of the sample of eleven Near-Earth Objects evaluated, there was a major improvement in the predicted position. This technique will likely improve the discovery rate of all NEOs from Pan-STARRS, but with particular benefit to the smaller (nearby) NEOs.
Negative Group Delay Enabled Artificial Transmission Line Exhibiting Squint-Free, Dominant Mode, Backward Leaky-Wave Radiation

A dispersion-engineered artificial transmission line (TL) enabled by negative group delay (NGD) is proposed to exhibit squint-free dominant mode leaky-wave radiation. The unit cell of the proposed artificial TL is based on a multi-section directional coupler, which is used to generate the desired NGD, followed by a composite right/left-handed transmission line (CRLH-TL) structure. An amplifier is incorporated within each unit cell to compensate for the power loss from the NGD coupler. By incorporating the NGD response, the resulting artificial TL can demonstrate a dispersionless fast wave characteristic within the NGD frequency band. For proof-of-concept, prototypes of a single unit cell and a three-unit cell NGD artificial TL are fabricated and tested to verify the dispersion and radiation characteristics. The measured radiation patterns of the proposed NGD artificial TL indicate that the main beam angle is located at -35 degrees in the backward direction, with a squint-free bandwidth from 2.55 GHz to 2.75 GHz.
A high-throughput assay for directly monitoring nucleolar rRNA biogenesis

Studies of the regulation of nucleolar function are critical for ascertaining clearer insights into the basic biological underpinnings of ribosome biogenesis, and for future development of therapeutics to treat cancer and ribosomopathies. A number of high-throughput primary assays based on morphological alterations of the nucleolus can indirectly identify hits affecting ribosome biogenesis. However, there is a need for a more direct high-throughput assay for nucleolar function to further evaluate hits. Previous reports have monitored nucleolar RNA biogenesis using 5-ethynyl uridine (5-EU) in low-throughput. We report a miniaturized, high-throughput 5-EU assay for nucleolar function which enables specific calculation of nucleolar rRNA biogenesis inhibition, based on co-staining of the nucleolar protein fibrillarin (FBL). The assay utilizes two siRNA controls, a negative non-targeting siRNA control (siNT) and a positive siRNA control targeting POLR1A (siPOLR1A), and specifically quantifies median 5-EU signal within nucleoli. Maximum nuclear 5-EU signal can also be used to monitor the effects of putative small molecule inhibitors of RNAP1, like BMH-21, or other treatment conditions that cause FBL dissociation. We validate the 5-EU assay on 68 predominately nucleolar hits from a high-throughput primary screen, showing that 58/68 hits significantly inhibit nucleolar rRNA biogenesis. Our new method establishes direct quantification of nucleolar function in high-throughput, facilitating closer study of ribosome biogenesis in health and disease.
Fate of recombinant Escherichia coli K-12 strains in the environment.

Publisher Summary This chapter discusses the fate of recombinant Escherichia coli K-12 strains in the environment. The strains of E. coli K-12 are unable to adhere to mammalian intestinal cells and do not colonize the conventional mammalian intestinal tract. The E. coli K-12 strains are able to colonize germ-free or antibiotic-treated rats and mice but not antibiotic-treated humans. The presence of conjugative and nonconjugative plasmids was observed to impart an additional disadvantage to E. coli K-12 strains in these environments, particularly in the mammalian intestinal tract. For the conjugational transfer of pBR322 or a derivative of pBR322, several conditions must be met. The pBR322 plasmid must have intact bom and nic sites; a derivative, such as pBR327, which lacks these two sites, is unable to be transferred. The fate of recombinant E. coli K-12 strains in the environment is an important and interesting issue that can continue to attract increased attention.
Do Korean-Americans View Drug Advertisements Differently Than Non-Hispanic White Americans?: Perceptions of Direct-to-Consumer Media: How Useful Is the Information They Convey?

ABSTRACT The Korean-American market segment is distinct, economically powerful, and underexamined. This study compared perceived information utility of six direct-to-consumer advertising (DTCA) media for prescription drugs among Korean-Americans and Non-Hispanic White Americans. Results indicate that drug-brand Web sites were most useful for this segment, followed by television. Banner, pop-up, and e-mail advertisements were least useful. Korean-Americans perceived newspapers, television, and the Internet significantly more useful DTCA media than Non-Hispanic Whites.
Chapter 14 Developments in manufacturing technology and economic evaluation models

Publisher Summary This chapter describes developments in technologies for automated, integrated manufacturing and theoretical models for the economic evaluation of those technologies. The chapter discusses the technology that is supporting automation and integration in manufacturing. Some of this technology, such as Computer-Aided Design (CAD) and robotics, is reasonably well established and productively employed in many locations. The managerial challenges to adopting those technologies are discussed in the chapter. Some conceptual underpinnings for considering economic evaluation of manufacturing technology investments are presented and the theoretical models of economic evaluation of manufacturing technology are reviewed. The chapter examines the contributions of the model-based theoretical work from management science and operations research (and to some extent, economics) for use in evaluation of technology investments to support automation and integration. Models described are divided into three groups, based on the economic phenomena they consider: (1) flexibility as a hedge against uncertainty, (2) interactions between flexibility and inventory, (3) flexibility as a strategic variable that influences competitors' actions.
User expectations of online information

User's expectations that the display screens used in online documentation will be understandable, transparent as to mechanics, intelligent in dynamic interaction, animated, and capable of being read at an acceptable speed are discussed. Ways of meeting these expectations are presented, and areas of future research are suggested.
A quantitative model-based expert system for LAN development

A quantitative model-based expert system, or QMB for short, is described. A QMB is a rule-based system coupled to an analytic model. The QMBs provide another level of refinement over rule-based systems by giving quantitative answers to problems. He discusses the difficulties associated with the design of a shell for a QMB and proposes the use of a semishell, which assists the knowledge engineers in writing the logic, uncertainty and inference modules of the QMB expert system program. The design and coding of the modules that deal with the numerical data is left to the knowledge engineer. The operation of a QMB having 43 rules is described. A software architecture is presented that can dynamically change its operation. The purpose of the architecture is to produce an expert system that can think more like human beings. >
Approximation Through Local Optimality: Designing Networks with Small Degree

We give quasipolynomial-time approximation algorithms for designing networks with minimum degree. Using our methods, one can design one-connected networks to meet a variety of connectivity requirements. The degree of the output network is guaranteed to be at most (1+e) times optimal, plus an additive error of O(log n/e) for any es0. We also provide a quasipolynomial-time approximation algorithm for designing a two-edge-connected spanning subgraph of a given two-edge-connected graph of approximately minimum degree. The performance guarantee is identical to that for one-connected networks.
Concurrent validity and classification accuracy of the Leiter and Leiter-R in low-functioning children with autism.

The concurrent validity of the Leiter International Performance Scale (Leiter) and Leiter International Performance Scale-Revised (Leiter-R) was examined in a sample of children with autism who could not be assessed with more traditional measures of intelligence (e.g., the Wechsler scales). The sample consisted of 26 children ranging in age from 4 to 16 years. The correlation between the Leiter scales was high (r = .87), and there was a difference of 3.7 points between the two mean scores, nonsignificant at both statistical and clinical levels. However, significant intraindividual discrepancies were present in 10 cases, 2 of which were both large (24 and 36 points) and clinically meaningful. The mean profile of performance on Leiter-R subtests is also presented for this sample of children with autism, to allow for comparison with other groups. Based on the results of this initial evaluation, together with the current normative data, good psychometric properties, and availability of global and subtest scores with the Leiter-R, the instrument is generally recommended for use with children with autism. However, because of changes in the design of the Leiter-R, there may be greater clinical success with the original Leiter for those children who are very low functioning and severely affected, particularly younger children.
Uterine contractility during altered vascular pressure in the castrated monkey.

Abstract Experiments on castrated rhesus monkeys, assessing uterine contractile patterns and their response to pressor and depressor agents, are presented. Castration results in a change in the coordinated pattern of spontaneous myometrial activity seen during the menstrual cycle, eventually resulting, after a long period of poorly coordinated contractile complexes, in relative uterine quiescence. The myometrium, supported by ovarian hormones, responds to pressor and depressor agents in a manner similar to that observed in the vascular tree. The castrate uterus, however, responds to vascular depressor agents with stimulation, rather than inhibition. In the absence of ovarian hormones, therefore, the nature of receptor sites within the myometrial cell membrane may be changed, so that inhibition can no longer be produced.
The pricing of community supported agriculture shares: evidence from New England

Purpose – Community supported agriculture (CSA) programs allow consumers to buy a share of a farm’s production while providing working capital and risk management benefits for farmers. Several different types of CSA arrangements have emerged in the market with terms varying in the degree to which consumers share in the farm’s risk. No-arbitrage principles of futures and options pricing suggest that CSA shares should be priced to reflect the degree of risk transfer. The paper aims to discuss these issues. Design/methodology/approach – The authors evaluate the three most common share types using a cross-sectional data set of 226 CSA farms from New England to determine if there is empirical evidence in support of the theoretical price relationship between share types. Findings – The degree of risk transfer from farmers to consumers has a significant effect on the share price. There are statistically significant returns to scale and higher prices for organics. Farm characteristics and product offerings predic...
Assessing mutant huntingtin fragment and polyglutamine aggregation by atomic force microscopy

Huntington disease (HD), a neurodegenerative disorder, is caused by an expansion of more than 35-40 polyglutamine (polyQ) repeats located near the N-terminus of the huntingtin (htt) protein. The expansion of the polyQ domain results in the ordered assembly of htt fragments into fibrillar aggregates that are the main constituents of inclusion bodies, which are a hallmark of the disease. This paper describes protocols for studying the aggregation of mutant htt fragments and synthetic polyQ peptides with atomic force microscopy (AFM). Ex situ AFM is used to characterize aggregate formation in protein incubation as a function of time. Methods to quickly and unambiguously distinguish specific aggregate species from complex, heterogeneous aggregation reactions based on simple morphological features are presented. Finally, the application of time lapse atomic force microscopy in solution is presented for studying synthetic model polyQ peptides, which allows for tracking the formation and fate of individual aggregates on surfaces over time. This ability allows for dynamic studies of the aggregation process and direct observation of the interplay between different types of aggregates.
New advances in organic photorefractive material development

The rapid improvement of the performance of photorefractive polymers over the past few years has generated a strong technological interest for these new materials. The areas of application include holographic storage, image processing, optical correlation, and phase conjugation. This paper reviews some of our recent advances in the field of organic photorefractive materials. We will first present several new polymeric composites that combine high efficiency and long shelf lifetimes. Then we will discuss the performance of a new class of organic photorefractive materials: photorefractive polymer dispersed liquid crystals. Finally, we will present two examples of applications based on photorefractive polymers: (i) optical correlators for security verification, and (ii) imaging through scattering media in the near infra-red.
Micro-pixelation and color mixing in biological photonic structures (presentation video)

The world of insects displays myriad hues of coloration effects produced by elaborate nano-scale architectures built into wings and exoskeleton. For example, we have recently found many weevils possess photonic architectures with cubic lattices. In this talk, we will present high-resolution three-dimensional reconstructions of weevil photonic structures with diamond and gyroid lattices. Moreover, by reconstructing entire scales we found arrays of single-crystalline domains, each oriented such that only selected crystal faces are visible to an observer. This pixel-like arrangement is key to the angle-independent coloration typical of weevils—a strategy that could enable a new generation of coating technologies.
Self-Assembly of n-Alkyl Thiols as Disulfides on Au(111)

A grazing incidence x-ray diffraction study of CH(3)(CH(2))(9)SH self-assembled on the (111) surface of gold revealed a disulfide head group structure, which provides a context in which to understand the structure and self-assembly process of this widely studied system. The structure consists of a nearly hexagonal two-dimensional arrangement of the hydrocarbon chains with a dimerization of the sulfur head groups (accommodated through a gauche bond), resulting in a S-S spacing of 2.2 angstroms. These results demonstrate the importance of internal molecular degrees of freedom in the templating of "soft" organic materials on inorganic substrates.
A concept of intracellular transmission of excitation by means of the endoplasmic reticulum.

Die morphologische Beobachtung von getrennten cytoplasmatischen Phasen in geschlossenen Membranen fuhrt zur Annahme von Membranpotentialen innerhalb der Zelle. Schreibt man den Membranen des endoplasmatischen Reticulums die Eigenschaften der Plasmamembran zu, so leiten sie die Erregung ins Zellinnere und dienen als Potentialspeicher.
Road traffic deaths in Guyana fifteen years of age and under. A review of seven years from 1979 to 1985 with a note on reduction and prevention

Abstract This article gives an idea of the problems of traffic control and traffic legislation in Guyana. It also overlaps on town and country planning and shows the need for coordination at government levels in all departments.
Temperature dependence of the crystalline quality of AlN layer grown on sapphire substrates by metalorganic chemical vapor deposition

Abstract We studied temperature dependence of crystalline quality of AlN layers at 1050–1250 °C with a fine increment step of around 18 °C. The AlN layers were grown on c -plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD) and characterized by X-ray diffraction (XRD) ω-scans and atomic force microscopy (AFM). At 1050–1068 °C, the templates exhibited poor quality with surface pits and higher XRD (002) and (102) full-width at half-maximum (FWHM) because of insufficient Al atom mobility. At 1086 °C, the surface became smooth suggesting sufficient Al atom mobility. Above 1086 °C, the (102) FWHM and thus edge dislocation density increased with temperatures which may be attributed to the shorter growth mode transition from three-dimension (3D) to two-dimension (2D). Above 1212 °C, surface macro-steps were formed due to the longer diffusion length of Al atoms than the expected step terrace width. The edge dislocation density increased rapidly above 1212 °C, indicating this temperature may be a threshold above which the impact of the transition from 3D to 2D is more significant. The (002) FWHM and thus screw dislocation density were insensitive to the temperature change. This study suggests that high-quality AlN/sapphire templates may be potentially achieved at temperatures as low as 1086 °C which is accessible by most of the III-nitride MOCVD systems.
Acute hormonal regulation of cyclic AMP content and glycogen phosphorylase activity in fetal liver in organ culture.

Acute hormonal regulation of fetal rat liver cyclic AMP content and glycogen phosphorylase activity was examined in an organ culture system using explants from term fetuses. Phosphorylase was rapidly activated by epinephrine and glucagon; the respective minimally effective concentrations were 2 X 10−7M and 10−8M. The characteristics of the adrenergic response were denned. Following the addition of a high concentration (10−5M) of epinephrine: Phosphorylase activity increased to a maximum at one minute (the earliest time point examined) and remained unchanged for at least 30 min; cyclic AMP levels were also maximally elevated by one minute but then declined over the next 30 min. The beta antagonist propranolol blocked both effects of epinephrine; the alpha antagonist phentolamine was without effect. The predominantly beta agonist isoproterenol was much more effective in elevating cyclic AMP levels and in activating phosphorylase than the predominantly alpha agonist phenylephrine. We conclude: i. fetal rat l...
Response of fluctuating asymmetry to arsenic toxicity: support for the developmental selection hypothesis.

Abstract The effect of exposure to sodium arsenite during development was tested on adult fluctuating asymmetry (FA) in sternopleural bristle number, bristle number, body size and survivorship in Drosophila melanogaster . Three genetic strains of flies were used, CT-106, PVM and Oregon-R, and arsenite concentrations ranged from relatively mild, sub-lethal doses, to concentrations with pronounced negative effects on survivorship. At arsenite concentrations of 1.0 and 0.125 mM, mortality was on average 38% greater than in controls, and surviving flies emerged significantly smaller and had fewer bristles than controls. Neither the effect of arsenite or the genotype×environment interaction on asymmetry were significant. However, given the high mortality, any increase in FA could have been masked by the outcome of developmental selection against developmentally unstable phenotypes. We tested for this effect by contrasting FA values between (1) flies reared at the highest concentrations used previously, (2) flies reared at sub-lethal dosage, and (3) controls. Positional fluctuating asymmetry (PFA), which is expected to be a sensitive indicator of underlying developmental stability, was significantly reduced among flies reared at the highest concentration, and at which flies suffered significant mortality. Moreover, the slope of the regression relating mean PFA to emergence per bottle was significantly positive. These data support the hypothesis that developmental selection occurred in this experiment, and that the expected positive relationship between asymmetry and stress may be altered when the stressor eliminates individuals from the population. In contrast, FA of flies reared at sub-lethal dosage did not differ from that in controls, a result that fails to support the hypothesis that arsenite disrupts developmental stability. Our results call for caution in FA-based biomonitoring, especially of potentially lethal forms of stress, because in the presence of developmental selection, and under the common assumption that FA should increase under stress, erroneous conclusions may be drawn about the health and well being of a population. It is suggested that FA-based biomonitoring efforts integrate the use of FA with other bioindicators, and experimentally validate any expected FA-stress relationship before attempting to infer the presence of environmental stress.
Latitudinal patterns in leaf litter breakdown: is temperature really important?

SUMMARY 1. Forest stream food webs depend largely on input of dead riparian zone leaves for their energy, which is converted into living biomass by microbes, macroinvertebrates and fish. 2. Temperature has been invoked as important in controlling breakdown rates, and aquatic biologists have suggested that by normalizing processing rates to degree days rather than days, one can ‘factor out’ the effect of temperature and compare processing rates in streams with different thermal regimes (e.g. different seasons or study sites in different biomes). 3. We examined processing rates (k) along a latitudinal (i.e. thermal) gradient by using reciprocal transplants of leafpacks. We placed leafpacks of ten tree species (representing a large range of leaf litter quality) in streams in Costa Rica, Michigan and Alaska using coarse-mesh (20mm) litter bags. We then examined both the ‘per day’(kday) and ‘per degree day’ (kdegree day) models of leaf litter processing. While processing rates (per day) were fastest at the Costa Rica site (as expected), rates at the Alaska and Michigan sites were similar to each other, which we would not predict if temperature were the principal factor controlling breakdown rate. If using degree days eliminates any effect of differing thermal regimes, rates should be similar across latitudes; however, rates at the Alaska site were much faster (per degree day) than rates at the sites in Costa Rica and Michigan. 4. We compared our data with studies in the North American literature. Regression analysis of kday and kdegree day against latitude of the study site revealed that processing rates (kday) of leaves (from a wide range of tree species in a wide range of stream types) showed no significant change with increasing latitude. However, when normalized for temperature (kDegree day), a positive correlation was found between processing rates and latitude, causing us to reject the hypothesis that normalizing processing rates to cumulative degree days removes the effect of temperature. 5. We suggest three hypotheses: (i) shredding insect populations have adapted to the local thermal regime, and invertebrate-mediated processing rates are either similar between regions (showing no latitudinal pattern), or increase with latitude; (ii) microbial populations are less active at colder temperatures, and the rate of microbially mediated processing of leaf litter will show a decrease with latitude, and consequently (iii) the relative importance of invertebrate v microbial processing changes on a latitudinal gradient, with invertebrates being more important at high latitudes.
Sub-mm-wave technologies: Systems, ICs, THz transistors

MM-wave and sub-mm-wave outdoor communications links have high available bandwidth and can support multiple independent spatial transmission channels but suffer from extremely high worst-case foul-weather attenuation. Link analysis suggests that several useful systems can be realizing using power amplifiers with ~50-200 mW output power, low-noise amplifiers with ~4-7 dB noise figure, and arrays of ~64-128 elements. Such systems can be realized with Si VLSI beamformers, InP HEMT LNAs, and InP HBT or GaN HEMT power amplifiers.
Obese African-American Women’s Perspectives on Weight Loss and Bariatric Surgery

Background African-American (AA) women have higher rates of obesity and obesity-related diseases but are less likely than other women to undergo bariatric surgery or have success with conventional weight loss methods.
Finite duration and energy effects in Lorentz-violating vacuum Cerenkov radiation

Abstract Vacuum Cerenkov radiation is possible in certain Lorentz-violating quantum field theories, when very energetic charges move faster than the phase speed of light. In the presence of a CPT-even, Lorentz-violating modification of the photon sector, the character of the Cerenkov process is controlled by the high-frequency behavior of the radiation spectrum. The development of the Cerenkov process can be markedly different, depending on whether the only limits on the emission of very energetic photons come from energy–momentum conservation or whether there are additional effects that cut off the spectrum at high frequencies. Moreover, since the high-frequency cutoff determines the total rate at which an emitting charge loses energy, it also controls all aspects of the emission that are related to the process's finite duration.
Agendas, Agencies and Unilateral Action: New Insights on Presidential Power?

Howell, William G. Power Without Persuasion: The Politics of Direct Presidential Action. Princeton, NJ: Princeton University Press, 2003. Pp. xx, 239. $45.00 hardbound, $19.95 softbound. Lewis, David E. Presidents and the Politics of Agency Design. Stanford, CA: Stanford University Press, 2003. Pp. xiii, 224. $45.00 hardbound. Rudalevige, Andrew. Managing the President's Program: Presidential Leadership and Legislative Policy Formulation. Princeton, NJ: Princeton University Press, 2002. Pp. xiii, 274. $60.00 hardbound, $18.95 softbound.