cssi/SciSciGPT-SciSciNet huggingface dataset:
Reinforcement and divergence under assortative mating

Traits that cause assortative mating such as the flowering time in plants and body size in animals can produce reproductive isolation between hybridizing populations. Can selection against unfit hybrids cause two populations to diverge in their mean values for these kinds of traits? Here I present a haploid analytical model of one population that receives gene flow from another. The partial pre–zygotic isolation between the two populations is caused by assortative mating for a trait that is influenced by any number of genes with additive effects. The post–zygotic isolation is caused by selection against genetic incompatibilities that can involve any form of selection on individual genes and gene combinations (epistasis). The analysis assumes that the introgression rate and selection coefficients are small. The results show that the assortment trait mean will not diverge from the immigrants unless there is direct selection on the trait favouring it to do so or there are genes of very large effect. The amount of divergence at equilibrium is determined by a balance between direct selection on the assortment trait and introgression from the other population. Additional selection against hybrid genetic incompatibilities reduces the effective migration rate and allows greater divergence. The role of assortment in speciation is discussed in the light of these results.
Coordination between child welfare agencies and mental health service providers, children's service use, and outcomes.

Objective Interorganizational relationships (IORs) between child welfare agencies and mental health service providers may facilitate mental health treatment access for vulnerable children. This study investigates whether IORs are associated with greater use of mental health services and improvement in mental health status for children served by the child welfare system.
The Prosthodontic Management of Endodontically Treated Teeth: A Literature Review. Part III. Tooth Preparation Considerations

The final part of this literature review series presents guidelines for the optimal preparation of teeth to receive posts and cores.
Social Responsibility and Corporate Reputation: The Case of the Arthur Andersen Enron Audit Failure

We examine the influence of social responsibility ratings on market returns to Arthur Andersen (AA) clients following the Enron audit failure. Chaney and Philipich (2002) found that AA's loss of reputation resulted in negative market returns to AA clients following the Enron audit failure. Proponents of social responsibility argue that social responsibility can improve the reputation of the firm, while detractors argue that social responsibility expenditures are a poor use of shareholder money. If social responsibility sends a signal to investors regarding the reputation/ethics of management, social responsibility could mitigate the negative returns to AA clients following the Enron audit failure. Using a matched sample of AA and non-AA firms, we do not find evidence that social responsibility mitigated the negative returns to AA clients following the Enron audit failure. Our results are inconsistent with claims that social responsibility can burnish a firm's reputation in a time of crisis and with prior research indicating a positive relationship between social responsibility and market value.
Video Streaming with Network Coding

Recent years have witnessed an explosive growth in multimedia streaming applications over the Internet. Notably, Content Delivery Networks (CDN) and Peer-to-Peer (P2P) networks have emerged as two effective paradigms for delivering multimedia contents over the Internet. One salient feature shared between these two networks is the inherent support for path diversity streaming where a receiver receives multiple streams simultaneously on different network paths as a result of having multiple senders. In this paper, we propose a network coding framework for efficient video streaming in CDNs and P2P networks in which, multiple servers/peers are employed to simultaneously stream a video to a single receiver. We show that network coding techniques can (a) eliminate the need for tight synchronization between the senders, (b) be integrated easily with TCP, and (c) reduce server's storage in CDN settings. Importantly, we propose the Hierarchical Network Coding (HNC) technique to be used with scalable video bit stream to combat bandwidth fluctuation on the Internet. Simulations demonstrate that under certain scenarios, our proposed network coding techniques can result in bandwidth saving up to 60% over the traditional schemes.
Spectroscopic studies of the DNA binding site of the GAL4 “zinc finger” protein

The yeast GAL4 protein, a transcriptional activator of genes involved in galactose metabolism, binds as a dimer to several closely related seventeen base pair upstream activation sequences (UASGs) that are nearly symmetric about a central dT-dA base pair. A previous study of a GAL4-UASG complex (Carey, M., Kakidani, H., Leatherwood, J., Mostashari, F. and Ptashne, M. (1989) J. Mol. Biol. 209, 423-432) elucidated a pattern of contacts consistent with the protein partially wrapping itself around the helical cylinder, assuming a B-form conformation for the DNA. Alternatively, both monomers could sit on one face of the cylinder if the DNA exists in an underwound conformation such as A-form. Spectroscopic studies that distinguish between these models are reported here. Oligonucleotides containing the consensus UASG or a nine base pair "half site" both exhibit circular dichroism (CD) spectra characteristic of B-form DNA. Two-dimensional NMR studies of the half-site also indicate a B-form conformation. When a GAL4 protein fragment containing the entire DNA-binding and dimerization domains (amino acids 1-140) is bound to the UASG, the CD spectrum above 240 nm changes only slightly, and not in a manner consistent with DNA unwinding. Our studies suggest that the UASG does not adopt an unusual underwound conformation in the absence or presence of the GAL4 protein, and favor the model in which the dimer partially wraps around the helix cylinder.
Contour metrology using critical dimension atomic force microscopy

The critical dimension atomic force microscope (CD-AFM), which is used as a reference instrument in lithography metrology, has been proposed as a complementary instrument for contour measurement and verification. Although data from CD-AFM is inherently three dimensional, the planar two-dimensional data required for contour metrology is not easily extracted from the top-down CD-AFM data. This is largely due to the limitations of the CD-AFM method for controlling the tip position and scanning. We describe scanning techniques and profile extraction methods to obtain contours from CD-AFM data. We also describe how we validated our technique, and explain some of its limitations. Potential sources of error for this approach are described, and a rigorous uncertainty model is presented. Our objective is to show which data acquisition and analysis methods could yield optimum contour information while preserving some of the strengths of CD-AFM metrology. We present comparison of contours extracted using our technique to those obtained from the scanning electron microscope (SEM), and the helium ion microscope (HIM).
Guanine nucleotides do not inhibit tritiated dopamine agonist binding to bovine striatal membranes

The addition of GTP (50 μM), MnCl2 (1 mM) or EDTA (2 mM) had no effect on the affinity or capacity of bovine striatal plasma membranes for [3H]spiperone. However, GTP caused a decrease in the potency of dopamine as an inhibitor of [3H]spiperone binding under all conditions tested. Manganese enhanced the potency of dopamine both in the presence and absence of GTP, but NaCl (100 mM) had no effect. Neither manganese nor GTP caused any change in the affinity or capacity of bovine striatal membranes for the tritiated agonists dopamine, apomorphine or ADTN. GPPNHP, a nonhydrolyzable analog of GTP, was also ineffective. However, in identical experiments using rat striatal membranes, 50 μM GTP caused a decrease in affinity for all three tritiated agonists and this effect was observed both in the presence and absence of manganese (1 mM). In addition, binding capacities for [3H]dopamine and [3H]ADTN were doubled when manganese was present. In light of this and other reports that GTP inhibits tritiated agonist binding in rat striatum, it is suggested that the absence of such inhibition in bovine striatal membranes may reflect a fundamental difference between the two species with regard to their receptors for dopamine agonists.
Influence of Milkweed Fiber Length on Textile Product Performance

Farmers and scientists joined forces in the late 1980s to develop milkweed as an alternative crop and source offiber. Efforts continue to develop milkweed floss fiber as an insulative fill material...
Learning Probabilistic Hierarchical Task Networks as Probabilistic Context-Free Grammars to Capture User Preferences

We introduce an algorithm to automatically learn probabilistic hierarchical task networks (pHTNs) that capture a user's preferences on plans by observing only the user's behavior. HTNs are a common choice of representation for a variety of purposes in planning, including work on learning in planning. Our contributions are twofold. First, in contrast with prior work, which employs HTNs to represent domain physics or search control knowledge, we use HTNs to model user preferences. Second, while most prior work on HTN learning requires additional information (e.g., annotated traces or tasks) to assist the learning process, our system only takes plan traces as input. Initially, we will assume that users carry out preferred plans more frequently, and thus the observed distribution of plans is an accurate representation of user preference. We then generalize to the situation where feasibility constraints frequently prevent the execution of preferred plans. Taking the prevalent perspective of viewing HTNs as grammars over primitive actions, we adapt an expectation-maximization (EM) technique from the discipline of probabilistic grammar induction to acquire probabilistic context-free grammars (pCFG) that capture the distribution on plans. To account for the difference between the distributions of possible and preferred plans, we subsequently modify this core EM technique by rescaling its input. We empirically demonstrate that the proposed approaches are able to learn HTNs representing user preferences better than the inside-outside algorithm. Furthermore, when feasibility constraints are obfuscated, the algorithm with rescaled input performs better than the algorithm with the original input.
Patient and graft survival in hepatitis C recipients after adult living donor liver transplantation in the United States

End stage liver disease from chronic hepatitis C is the leading indication for liver transplantation in the United States. Small studies suggest that recurrent hepatitis C may be more common and occur earlier after living donor liver transplantation compared to deceased donor liver transplantation. The objective of our study was to analyze the United Network for Organ Sharing liver transplant database to compare patient and graft survival in recipients transplanted for chronic hepatitis C who received a living donor organ and deceased donor organ between 1999 and 2002. We identified 279 living donor recipients and 3955 deceased donor recipients. Living donor recipients were less ill at the time of transplant, more likely to be female, and received grafts from younger donors. In the living donor group and deceased donor group, 1-year graft survival was 77% and 82%, respectively, and 2-year graft survival was 72% and 75%, respectively, P =.11. One-year patient survival was 87% in both groups and 2-year patient survival was 83% and 81% in the living donor group and deceased donor group, respectively, P =.68. Short-term patient and graft survival are similar between living donor and deceased donor liver transplant recipients with hepatitis C suggesting that recurrent hepatitis C does not seem to affect short-term outcomes.
A comprehensive modeling framework for airborne mobility

Mobility models serve as the foundation for evaluating and designing airborne networks. Due to the significant impact of mobility models on the network performance, mobility models for airborne networks (ANs) must realistically capture the attributes of ANs. In this paper, I develop a comprehensive modeling framework for ANs. The work I have done is concluded as the following three parts. First, I perform a comprehensive and comparative analysis of AN mobility models and evaluate the models based on several metrics: 1) networking performance, 2) ability to capture the mobility attributes of ANs, 3) randomness levels and 4) associated applications. Second, I develop two 3D mobility models and realistic boundary models. The mobility models follow physical laws behind aircraft maneuvering and therefore capture the characteristics of aircraft trajectories. Third, I suggest an estimation procedure to extract parameters in one of the models that I developed from real flight test data. The good match between the estimated trajectories and real flight trajectories also validate the suitability of the model. The mobility models and the estimation procedure lead to the creation of “realistic” simulation and evaluation environment for airborne networks.
Electronic transport of molecular systems

We report stable and reproducible switching and memory effects in self-assembled monolayers (SAMs). We demonstrate realization of negative differential resistance (NDR) and charge storage in electronic devices that utilize single redox-center-contained SAM as the active component; and compare the effects of various redox centers to switching and storage behavior. The devices exhibit electronically programmable and erasable memory bits with bit retention times greater than 15 min at room temperature.
A Load Balancing Scheme for ebXML Registries

Large scale Service Oriented Architecture (SOA) developments are becoming increasingly reliant on registry services that manage Web Services using taxonomic attributes. At present a registry stores a Web Services interface definition and protocol bindings in WSDL, along with one or more XML schema files that define the structure of a SOAP message exchanged between Web Services operations and client processes and other static metadata. During Web Service discovery an ebXML registry returns the access URI associated with the service binding to allow dynamic discovery and invocation. This usually restricts a calling process to a Web Service invocation on one host. This work explores a mechanism to manage service bindings for a Web Service that has been deployed across multiple hosts, such that, a URI returned by a registry can resolve to a host that satisfies different system constraints like current CPU load, physical memory, swap memory, and time of day. This paper discusses the design and development of new scheme for ebXML registries that facilitates periodic collection and management of dynamic system properties for registry clients and enforces constraints during service discovery and query operation.
Study of protonated methanol cluster ions under thermal conditions

Abstract Size-dependent intracluster reactions within the methanol cluster system are studied using a fast flow reactor operated under thermal conditions. At low temperature, large protonated methanol cluster ions (CH 3 OH) n H + ( n up to 24) are produced for the first time under thermal conditions. Two mixed cluster ion series of (CH 3 OH)) n (CH 3 OCH 3 )H + and (CH 3 OH) n (H 2 O)H + are also observed. Interestingly, the cluster ion patterns are found to be greatly influenced by the degree of solvation, due to several size specific intracluster ion—molecule reactions. The mixed cluster ions (CH 3 OH) n (CH 3 OCH 3 )H + are observed only for the small clusters ( n ⩽5) while the mixed cluster ions (CH 3 OH) n (H 2 O)H + are seen only for the large ones ( n ⩾7). The work reported herein is particularly significant in that it demonstrates under thermal conditions, the influence of the degree of solvation on the course of intracluster ion—molecule reactions. Moreover, these new findings further support what is becoming a general observation concerning the role of the number of bonding sites in affecting the chemical nature of the ion core in mixed clusters.
Photoperiodic induction of pupal diapause in the flesh fly,Sarcophaga crassipalpis: embryonic sensitivity

The last two days of embryonic development are crucial in programming pupal diapause in the flesh fly,Sarcophaga crassipalpis. Short daylength (greater than 10 1/2h of darkness) during this interval permits expression of diapause while long daylength during this brief sensitive stage eliminates the potential for diapause. Length of scotophase rather than photophase programs the diapause although three hours of light is needed to separate tandem dark periods. Early in the scotophase, photosensitivity is restricted to blue light (less than 540 nm). The scotophase can be divided into 4 phases according to the effect of light breaks on diapause expression. During Phase I (0–6 h after scotophase onset) embryos are highly sensitive to light interruption and diapause is effectively eliminated. A period of insensitivity to light, Phase II, extends from 6–hh after onset of scotophase. Light breaks at 10–11h coincide with the critical scotophase length and result in a partial reduction of diapause. In Phase IV, the scotophase reaction is complete and diapause competence is preserved even in the presence of light. Although light breaks result in elimination of diapause throughout Phase I, recovery time from a 1 h light break (length of darkness needed to counter the effect of a light break) differs dramatically depending upon when the light break is presented. Early in Phase I (0–3h) recovery from light interruption is rapid, while late in Phase I (4–6h), the effects of light are not readily reversible. The scotophase reaction thus appears to follow a step-wise progression rather than represent a simple linear response. We present a molecular model that could account for the dynamics of the scotophase reaction.
Thought suppression and suicidal ideation: preliminary evidence in support of a robust association.

Background: The suppression of unwanted thoughts appears to contribute to the development and maintenance of emotional disorders. This report tested the thought suppression paradigm in relation to suicidal ideation. Based on the ironic process theory, we hypothesized that the suppression of unwanted thoughts, especially suicidal thoughts, would associate with a higher frequency and a greater intensity of suicidal ideation. Methods: Study 1 examined cross-sectional associations between self-reported thought suppression and the frequency of suicidal ideation in a nonclinical sample of 166 undergraduate students. Study 2 extended cross-sectional findings in an inpatient sample of 71 suicidal adolescents. Study 3 examined prospective associations between suicidal thought suppression and increases in self-reported suicidal ideation over a 4-week period in a separate nonclinical sample of 118 undergraduate students. Results: Findings across studies support a robust association between thought suppression and suicidal ideation, even controlling for general depressive symptoms. Participants in Studies 1 and 2 who endorsed greater tendencies toward suppression of thoughts, especially suicidal thoughts (Study 2), displayed higher concurrent levels of suicidal ideation. Participants in Study 3 who endorsed greater baseline tendencies toward suppression of suicidal thoughts displayed an increase in the severity of suicidal ideation over time. Conclusions: Suppression of suicidal thoughts may represent 1 mechanism contributing to the persistence of suicidal ideation. Clinicians may wish to explore patients' reactions to suicidal ideation and consider acceptance-oriented strategies among patients who attempt to control unwanted suicidal thoughts. Depression and Anxiety, 2009. © 2008 Wiley-Liss, Inc.
Analyses of Quantitative Trait Loci Contributing to Alcohol Preference in HAD1/LAD1 and HAD2/LAD2 Rats

Background: The high-alcohol-drinking (HAD1/HAD2) and low-alcohol-drinking (LAD1/LAD2) rat lines, derived from the N/NIH rat, were developed by using a within-family selection and rotational breeding design for alcohol preference and alcohol consumption. Previously, a 20-cM genome screen identified quantitative trait loci (QTLs) on chromosomes 5, 10, 12, and 16 by using F2 progeny from HAD1 and LAD1 animals. Methods: A total of 459 F2 HAD1 × LAD1 animals had been previously genotyped, and 428 HAD2 × LAD2 F2 animals were genotyped for microsatellite markers within the identified QTL regions. Linkage analyses were performed with the program QTL Express, a recently developed Web-based interface that implements a least-squares method. Results: The linkage peaks previously identified in the HAD1 × LAD1 genome scan relied on one or two markers. Placement of additional markers in and around the QTL regions provided further support for each of the QTLs. Two of the QTLs on chromosomes 10 and 16 were confirmed in the replicate line; these QTLs exhibited linkage in both the HAD1/LAD1 and HAD2/LAD2 studies. Conclusions: This study demonstrated the importance of confirmation of QTLs in a replicate line, as well as the complexity of the genetic contribution to alcohol preference. Assessing these QTL regions in the inbred HAD/LAD animals will further facilitate characterization of these regions.
Real-time monitoring of immune responses

With the advent of cellular immunotherapy, the ability to monitor immune responses during treatment will be essential to evaluate the effectiveness of the new therapies. While the ultimate determinate of the success of immunotherapy trials will be clinical outcome, methods of monitoring immunity in real-time have become available that will assist in the development of immunotherapy strategies and in the prediction of individual patient prognosis during the course of treatment. The essentials of existing immune assays are described here with examples of how these techniques have been used previously. A perspective on which approaches will likely prove the most useful for monitoring immune responses in real-time during immunotherapy is also presented.
Do Fluctuations in Ovarian Hormones Affect Gastrointestinal Symptoms in Women With Irritable Bowel Syndrome

Background: An increase in gastrointestinal (GI) symptoms, including bowel discomfort, abdominal pain/discomfort, bloating, and alterations in bowel patterns, has been reported during premenses and menses menstrual cycle phases and the perimenopause period in women with and without irritable bowel syndrome (IBS). Objective: This article reviews the literature related to one possible physiological mechanism-declining or low ovarian hormone levels--that may underlie the occurrence or exacerbations of abdominal pain/discomfort at times of low ovarian hormones (menses, menopause) in women with or without IBS. Methods: To identify English-only review and data-based articles, PubMed was searched between January 1980 and September 2008 using the following terms: irritable bowel syndrome, functional gastrointestinal disorders, gastrointestinal motility, immune, pain, hyperalgesia, menstrual cycle, menopause, pregnancy, estrogen, estradiol (E(2)), and progesterone. Studies in animals and in humans were included; drug trials were excluded. Results: From our review of the literature, 18 papers were identified that were related either to the mechanisms accounting for menstrual cycle fluctuations (n = 12) or to the impact of menopausal status on symptoms of IBS (n = 6). One study reported that visceral pain sensitivity was significantly higher during menses than at other menstrual cycle phases in women with IBS (P < 0.05). Other menstrual cycle phase-linked symptoms, dysmenorrheal symptoms (cramping pain) in particular, were more intense in women with IBS. Animal studies have shed some light on the relationship of ovarian hormones to GI sensorimotor function. Conclusion: The increase in GI symptoms around the time of menses and early menopause occurs at times of declining or low ovarian hormones, suggesting that estrogen and progesterone withdrawal may contribute either directly or indirectly. This review highlights the need for confirmatory preclinical and clinical studies to unravel the role of ovarian hormones in women with IBS.
The Teaching of Spanish Literature: A Necessary Partnership between the Language and Literature Sections of Traditional Departments

Abstract: Students who are faced with literary texts after the beginning language sequence will be in for a shock if their instructors do not continue some of the strategies used in language classes; however, in most institutions until very recently, little or no time was spent on methods of teaching literary texts. Moreover, little time is devoted to the teaching of reading strategies. Many traditional Spanish departments divide language and literature into two separate programs, with little, if any, articulation between the two. This article describes the collaborative effort between a professor of literature and a professor of language methodology in the development and implementation of a teaching strategies course for undergraduates and a workshop on the teaching of literature for teaching assistants in the Department of Spanish and Portuguese at Ohio State University.
Applications For A General Purpose Optical Beam Propagation Code

Real world beam propagation and diffraction problems can rarely be solved by the analytical expressions commonly found in optics and lasers textbooks. These equations are typically valid only for paraxial geometries, for specific boundary conditions (e.g., infinite apertures), or for special assumptions (e.g., at focus). Numerical techniques must be used to solve the equations for the general case. LOTS, a public domain numerical beam propagation software package developed for this purpose, is a widely used and proven tool. The graphical presentation of results combined with a well designed command language make LOTS particularly user-friendly, and the recent implementation of LOTS on the IBM PC/XT family of desktop computers will make this capability available to a much larger group of users. This paper surveys several applications demonstrating the need for such a capability.
Mode of Reproduction and Development of the Reproductive System of Helicotylenchus Dihystera

The morphology of the adult female reproductive system was studied in Helicolylenchus dibystera and H. digonicus. In both species, it was found to comprise the following parts: Ovary (8.7 to 21.2 oogonia and oocytes in anterior gonad, 7.6 to 18.3 in posterior gonad of H. dihystera), narrow .constriction (four cells), tubular oviduct (sixteen cells), constriction (eight cells), dorsally bulging, nonfunctional spermatotheca (twelve cells), glandular tricolumella (twelve cells) and uterus proper. The final number of cells making up the spermatotheca is determined during the last molt, no cell divisions take place later in the adult. No spermatozoa could be demonstrated in the spermatotheca or in any other part of the gonoducts and reproduction was by mitotic parthenogenesis. The cells of the tricolumella have a secretory function and the material they produce appears to be deposited on the surface of the eggs. The post-embryonic development of H. dihystera comprises four larval stages and the adult. The first molt takes place within the egg. The three larval stages outside the egg can be recognized on the basis of the degree of development of the reproductive system. The reproductive system of each larval stage has a constant number of nuclei. Nuclear divisions in the reproductive system occur only during molting, whereas cell enlargement takes place mainly during the larval stages. The reproductive system consists of four nuclei in the second larval stage, fourteen nuclei in the third and 108 nuclei in the fourth larval stage. The final differentiation of the various gonadal parts takes place during the fourth molt. Specialized ventral chord nuclei and some other nuclei outside the gonad whose origin could not be determined take part in the formation of the vagina. One of the central nuclei of the gonad proper appears to function as vaginal organizer ("I" nucleus).
Advanced soft palate cancer: the clinical importance of the parapharyngeal space.

OBJECTIVE: To identify the incidence of parapharyngeal space (PPS) recurrences and how they impact survival in advanced-stage soft-palate carcinoma patients. STUDY DESIGN AND SETTING: One hundred thirty-seven patients' charts were reviewed from 1971 to 1996. Inclusion criteria were patients who received a per-oral resection, discontinuous neck dissection, and postoperative adjuvant radiation therapy; 15 patients met criteria for inclusion. The incidence of PPS recurrences, regional failure, and survival were endpoints that were analyzed. RESULTS: There were no local failures in our study. Regional failures excluding the PPS (levels I-V) were 27%, and 40% occurred within the PPS. Cervical adenopathy was associated with 83% of the PPS recurrences. Median survival for PPS recurrences was 26 months, compared with 67 months for levels I-V recurrences (n = ns). CONCLUSIONS: The incidence of PPS recurrences is substantial in advanced-stage soft-palate cancer. PPS recurrences negatively impact survival; without effective salvage techniques for these recurrences or effective adjuvant therapy, poor patient outcomes can be expected.
The expression pattern of the chick homeobox gene gMHox suggests a role in patterning of the limbs and face and in compartmentalization of somites

Abstract MHox is a homeodomain protein that binds an essential element in the core of the muscle creatine kinase enhancer. In the mouse embryo, MHox expression is restricted to mesenchymal cells; in adult mice the gene is highly expressed in skeletal and cardiac muscle. To further define the functions of MHox during embryogenesis, we have cloned its chicken homolog, termed gMHox , and analyzed its properties and detailed expression patterns. Our studies show that the amino acid sequence and DNA-binding properties of the avian and murine gene products are very similar. Furthermore, the sites of expression are alike with high levels of expression in the splanchnic mesoderm, in the somatic mesoderm, in the limb bud mesoderm, in the dermatome and in the dermis, and in the ectomesenchyme of the face. gMHox became downregulated as chondrogenesis proceeded, whereas its expression was maintained in perichondrium and undifferentiated mesenchymal cells beneath the surface ectoderm. Such a pattern of expression suggests that gMHox may participate in maintenance of mesenchymal cell lineages derived from both mesoderm and the neural crest and in patterning of the limbs and the face. Removal of the surface ectoderm overlying the somites has no visible effect on the architecture of somites but results in the failure of gMHox to be expressed in the underlying dermatome, suggesting that regulation of gMHox expression in these cells is dependent on cues emanating from the surface ectoderm.
Signal Suppression Analysis for the Momentum Stochastic Cooling with a Multiple System

The Tevatron I project at Fermilab depends critically on the momentum stochastic cooling to collect and store antiprotons produced by injecting protons on a target. This project differs from the similar original project at CERN by the fact that it requires greater antiproton flux. Moreover, the stochastic cooling design is made of several systems each with its own pickup, kickers, and chain of amplification. These systems could overlap in the frequency bandwidth as well as in the beam response dynamics. It has been argued, consequently, that the performance of the momentum cooling might have been limited by the signal suppression which one derives when examining the cooling system in closed loop. In this paper an analysis is made of the closed loop system for momentum stochastic cooling. In the closed loop configuration the electronic feedback depends not only on the electronic component characteristics but also on the beam intensity and energy distribution. The results give the interrelation between the signals from the different parts of the system and their mutual enhancement or suppression. The paper goes on to derive the Vlasov equation, to calculate the perturbation force, and to solve a larger number of dispersion relations.
Control of Arabidopsis apical–basal embryo polarity by antagonistic transcription factors

Plants, similarly to animals, form polarized axes during embryogenesis on which cell differentiation and organ patterning programs are orchestrated. During Arabidopsis embryogenesis, establishment of the shoot and root stem cell populations occurs at opposite ends of an apical-basal axis. Recent work has identified the PLETHORA (PLT) genes as master regulators of basal/root fate, whereas the master regulators of apical/shoot fate have remained elusive. Here we show that the PLT1 and PLT2 genes are direct targets of the transcriptional co-repressor TOPLESS (TPL) and that PLT1/2 are necessary for the homeotic conversion of shoots to roots in tpl-1 mutants. Using tpl-1 as a genetic tool, we identify the CLASS III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors as master regulators of embryonic apical fate, and show they are sufficient to drive the conversion of the embryonic root pole into a second shoot pole. Furthermore, genetic and misexpression studies show an antagonistic relationship between the PLT and HD-ZIP III genes in specifying the root and shoot poles.
HEAO 1 high energy X-ray observations of the Virgo cluster and A2142

Observations are reported of the Virgo cluster and Abell 2142 in the energy range of 15-150 keV, detected by using hard X-ray and low energy gamma-ray instruments on board the HEAO-1 spacecraft, during 1977 and 1978. The Virgo cluster was detected at a mean flux of (1.3 + or - 0.3) x 10 to the 0.001 photons/sq cm-s in the 20-100 keV band, and A2142 was detected marginally at a flux of (2 + or - 0.8) x 10 to the 0.001 photons/sq cm-s in the 15-40 keV band. Inverse Compton emission was not observed in these clusters. Results are used to derive limits to the intracluster magnetic field of B approximately greater than 5 x 10 to the -7th gauss and B approximately 5 x 10 to the -8th gauss in the Virgo cluster and A1242, respectively. There is some evidence for variability in these sources, which implies that the hard X-ray emission originates in a relatively compact object or region rather than from the cluster as a whole.
Fatal EBV-related post-transplant lymphoproliferative disorder (LPD) after matched related donor nonmyeloablative peripheral blood progenitor cell transplant.

A 39-year-old male underwent a nonmyeloablative stem cell transplant (NMAPBPCT) from his HLA-matched sister for recurrent anaplastic large cell lymphoma in CR-2, receiving fludarabine, cyclophosphamide, and rabbit antithymocyte globulin for the preparative therapy. The patient was readmitted on day+33 for persistent culture-negative fevers. He rapidly developed marked elevations of alkaline phosphatase and bilirubin. Liver biopsy showed a periportal infiltrate of large immunoblastic appearing cells. The tumor cells did not stain for CD3/CD20/CD30 and alk protein, but did stain for CD79a/LCA and CD43. In situ hybridization for Epstein–Barr virus (EBV) RNA (EBER 1) was strongly positive in the periportal infiltrating lymphocytes. Fluorescence in situ hybridization (FISH) studies revealed female (XX) cells in the tumor cells and male (XY) in the surrounding hepatic parenchymal cells. The patient developed severe lactic acidosis, oliguric renal failure and expired on day+44. Both donor and patient had positive IgG serologies for EBV VCA and EBNA pretransplant. The donor also had a positive IgM titer for EBV VCA in the pretransplant specimen. The LPD may have been related to the intense immunosuppression of the preparative therapy and the presence of recent EBV infection in the donor.
A Molecular Analysis of Hyalin—A Substrate for Cell Adhesion in the Hyaline Layer of the Sea Urchin Embryo

Abstract The hyaline layer of echinoderm embryos is an extraembryonic matrix that functions as a substrate for cell adhesion through early development. The major constituent of the hyaline layer is the protein hyalin, a fibrillar glycoprotein of approximately 330 kDa that multimerizes in the presence of calcium. Here we provide a molecular characterization of hyalin and identify a region of the protein that is important for its function in cell adhesion. Partial hyalin cDNAs were identified from two sea urchin species, Strongylocentrotus purpuratus and Lytechinus variegatus, by screening expression libraries with monoclonal antibodies to hyalin. The cDNAs each encode a tandemly arranged series of conserved repeats averaging 84 amino acids. These hyalin repeats are as similar between the two species as they are to repeats within each species, suggesting a strong functional conservation. Analysis of this repeat shows that it is a unique sequence within the GenBank database with only weak similarity to mucoid protein sequences. The hyalin mRNA is approximately 12 kb in length and is present in developing oocytes coincident with the appearance of cortical granules, the vesicle in which the hyalin protein is specifically packaged. The mRNA is present throughout oogenesis but is rapidly lost at oocyte maturation so that eggs and early embryos have no detectable hyalin mRNA. The hyalin protein, however, remains at relatively constant levels throughout development. Thus, all the hyalin protein present during early development, when no RNA is detectable, is maternally derived and exocytosed from cortical granules at fertilization. Hyalin mRNA reaccumulates in embryos beginning at the mesenchyme blastula stage; a RNA gel blot and in situ hybridization analysis of gastrulae and larvae shows a progressive confinement of hyalin mRNA to the aboral ectoderm. Recombinant hyalin containing the tandem repeat region of the protein was expressed in bacteria and is shown to serve as an adhesive substrate, almost equal to that of native hyalin, in cell adhesion assays. This adhesive activity is partially blocked by dilute hyalin monoclonal antibody Tg-HYL to the same extent as that for native hyalin. Thus, this hyalin repeat region appears to contain the ligand for the hyalin cell surface receptor. These data help explain some of the classic functions ascribed to the hyalin protein in early development and now enable investigators to focus on the mechanisms of cell interactions with the hyaline layer.
Spontaneous activity of A9 and A10 dopamine neurons after acute and chronic administration of the selective dopamine D-1 receptor antagonist SCH 23390

The effects of acute and chronic treatment with the selective dopamine (DA) D-1 antagonist SCH 23390 on the population response of midbrain DA cells were determined. One hour pretreatment with SCH 23390 (0.0125, 0.025, 0.05 mg/kg s.c.) caused a dose-related increase in the number of spontaneously firing DA neurons in both the A9 and A10 cell regions. Chronic (28 day) administration of SCH 23390 (0.05 mg/kg s.c.) caused depolarization inactivation of only A10 DA cells. These data suggest that SCH 23390 may have antipsychotic properties with a reduced likelihood of producing extrapyramidal side effects.
Sleep disordered breathing in patients receiving therapy with buprenorphine/naloxone

Patients using chronic opioids are at risk for exceptionally complex and potentially lethal disorders of breathing during sleep, including central and obstructive apnoeas, hypopnoeas, ataxic breathing and nonapnoeic hypoxaemia. Buprenorphine, a partial μ-opioid agonist with limited respiratory toxicity, is widely used for the treatment of opioid dependency and chronic nonmalignant pain. However, its potential for causing sleep disordered breathing has not been studied. 70 consecutive patients admitted for therapy with buprenorphine/naloxone were routinely evaluated with sleep medicine consultation and attended polysomnography. The majority of patients were young (mean±sd age 31.8±12.3 years), nonobese (mean±sd body mass index 24.9±5.9 kg·m(-2)) and female (60%). Based upon the apnoea/hypopnoea index (AHI), at least mild sleep disordered breathing (AHI ≥5 events·h(-1)) was present in 63% of the group. Moderate (AHI ≥15- <30 events·h(-1)) and severe (AHI ≥30 events·h(-1)) sleep apnoea was present in 16% and 17%, respectively. Hypoxaemia, defined as an arterial oxygen saturation measured by pulse oximetry, of <90% for ≥10% of sleep time, was present in 27 (38.6%) patients. Despite the putative protective ceiling effect regarding ventilatory suppression observed during wakefulness, buprenorphine may induce significant alterations of breathing during sleep at routine therapeutic doses.
Subcortical dementia: historical review and personal view.

I was skimming one of those throw-away neurology journals that we all receive, unrequested, in the mail, when my eye fell on a multi-colored table labeled “Cortical vs. Subcortical Dementia.” Befor...
Multifocal nodular episcleritis and scleritis with undiagnosed Hodgkin’s lymphoma☆

Abstract Purpose To report the case of a patient with undiagnosed Hodgkin's lymphoma who presented with coexistent unilateral nodular episcleritis and scleritis. Design Interventional case report and literature review Methods Review of clinical history, laboratory findings, histology of episcleral and cervical lymph node biopsies, and follow-up. Results A 20-year-old female presented with a 5-month history of redness and pain in her left eye, with associated symptoms of dyspnea, malaise, and fever. The patient was found to have multifocal nodular episcleritis and scleritis that was not responsive to topical steroids or systemic nonsteroidal anti-inflammatory treatment. Laboratory tests subsequently revealed evidence of systemic inflammation, and radiologic studies showed extensive mediastinal and cervical adenopathy. A cervical lymph node biopsy showed Reed–Sternberg cells and a chronic lymphocytic infiltrate consistent with nodular sclerosing Hodgkin's lymphoma. Histopathologic analysis of an episcleral nodule revealed a necrotizing granuloma with vasculitis. Systemic chemotherapy was instituted for the Hodgkin's disease; this therapy abolished the nodular scleritis. Conclusions This case raises the possibility of concurrent undiagnosed systemic vasculitis with only an ocular manifestation with Hodgkin's lymphoma, either as a coincidence or as a paraneoplastic syndrome. Moreover, it emphasizes the important role of tissue biopsy in establishing diagnosis and directing treatment. © 2003 by the American Academy of Ophthalmology.
Biological and oceanographic insights from larval labrid (Pisces: Labridae) identification using mtDNA sequences

Polymerase chain reaction and direct comparison of mitochondrial DNA sequences from a cytochrome b gene fragment were used to identify two morphologically distinct larval types ofXyrichtys, a genus of tropical wrasse (Pisces: Labridae). Both larval types were collected during ichthyoplankton surveys on the Middle Atlantic Bight shelf in the summer of 1988. DNA sequence comparisons indicated that both types were larvae ofXyrichtys novacula (Linnaeus). Back-calculated birthdate distributions for those larvae collected on the Middle Atlantic Bight shelf demonstrated that the two larval types formed two distinct cohorts indicating a biological difference. The two distinct larval types may be a consequence of an ecophenotypic effect, or they may represent offspring from genetically distinct populations. These results emphasize that important biological and oceanographic information can be gained through the use of the polymerase chain reaction and DNA sequencing for larval identificaiton.
The influence of phenolphthalein ingestion on red blood cell resistance to hemolysis

The resistance of erythrocytes of rats to hemolysis by saponin is decreased when these rats are fed sulfanilamide alone or sulfanilamide mixed with phenolphthalein. The feeding of phenolphthalein alone to rats does not cause any change in the red cell resistance. Hence, any hemolysis that may occur in subjects receiving both sulfanilamide and phenolphthalein is due to the sulfanilamide.
Computing gravity-driven viscous fingering in complex subsurface geometries: A high-order discontinuous Galerkin approach

We present a formulation of the discontinuous Galerkin method aimed for simulations of gravity-driven viscous fingering instabilities occurring in porous media flow. Specifically, we are targeting applications characterized by complex geometrical features. Viscous fingering instabilities play a very important role in carbon sequestration in brine aquifers. The proposed method has the ability to preserve high order of accuracy on completely unstructured meshes, a feature that makes it ideal for high-fidelity computations of the challenging fingering flow patterns and very complex geometries of actual reservoirs and aquifers. An extensive set of numerical computations is also included, to confirm the stability, accuracy, and robustness of the method.
Going under: The world's sinking deltas

River deltas all over the world are sinking, bringing catastrophic floods ever more often. Some major cities have sunk more than a metre already. So what's going on?
An automata theoretic decision procedure for the propositional mu-calculus

The propositional mu-calculus is a propositional logic of programs which incorporates a least fixpoint operator and subsumes the propositional dynamic logic of Fischer and Ladner, the infinite looping construct of Streett, and the game logic of Parikh. We give an elementary time decision procedure, using a reduction to the emptiness problem for automata on infinite trees. A small model theorem is obtained as a corollary.