cssi/SciSciGPT-SciSciNet huggingface dataset:
Salmonella typhimurium Mutants Defective in Cytidine Monophosphate Kinase (cmk)

Abstract Mutants of Salmonella typhimurium defective in cytidine 5′-monophosphate (CMP) kinase (cmk) have been isolated. The mutants also lack the ability to phosphorylate 2′-deoxyCMP, indicating that one enzyme is responsible for the phosphorylation of both CMP and deoxyCMP to the corresponding diphosphates. In glucose minimal medium the mutants grow at the same rate as the parental strain; however, they excrete large quantities of pyrimidines into the growth medium. Cytidine but not deoxycytidine has been identified among the excreted products. The mutant phenotype suggests that the physiological role of CMP kinase is that of rephosphorylating CMP arising from the breakdown of messenger ribonucleic acid. This proposed role of CMP kinase is supported by the fact that a cmk− mutant is much more sensitive to any partial impairment of cytidine 5′-triphosphate synthetase than is the cmk+ parent strain. The gene cmk has been located on the Salmonella chromosome at 38.5 min. No markers which can be cotransduced with cmk by phage P22 have been found.
The braincase of the Middle Triassic shark Acronemus tuberculatus (Bassani, 1886)

: The chondrocranium of the enigmatic Middle Triassic shark Acronemus tuberculatus is investigated using computerized tomography scanning and 3-D digital reconstitution techniques. The braincase reveals some autapomorphies, plus other features that suggest a phylogenetic relationship to both hybodontiform and neoselachian elasmobranchs, including evidence of features implicated in low-frequency semi-directional phonoreception. Acronemus can no longer be classified as a ‘ctenacanthiform’, although its relationships remain elusive and it presents supposedly hybodontiform and neoselachian features that have not previously been found in combination.
French History Textbooks as a Tool for Teaching Civilization

THE RECENT CONTROVERSY IN FRANCE over the new history textbooks based on the reforms promulgated under Ren6 Haby in the middle 1970s can serve as a reminder of the many uses such textbooks can have in our civilization classes. In the past ten years the Haby programs have become the symbol for what many observers in France take to be a serious weakening of the teaching of history since the late 1960s. At the primary level, history was joined to geography and the sciences as an activiti d'eveil; no longer was it the privileged instrument for fostering national identity as it had been in the schools of the Third Republic where the manuals of Ernest Lavisse ran through edition after edition. Critics charge that the changes at the secondary level have been equally damaging. The number of hours devoted to history has been reduced. Thematic study has weakened the traditional chronological framework punctuated by the dates of battles and political regimes. Finally, French national history has been diluted by situating it in a wider current of international affairs. The debate over these changes has not been confined to educational circles: it is widely reported in the popular press and has been raised at the highest levels of state. In August 1983, President Mitterrand addressed the issue at a cabinet meeting where he professed to be "scandalis6 et angoissb devant les carences de l'histoire" that threatened to lead to "la perte de la m6moire collective des nouvelles g6nbrations."' However, the quarrel over the Haby syllabi is not my subject, even though it is symptomatic of the changing role of tradition in the French value system. My concern is not so much the modalities of initiating French youth to their past as the role this heritage should play in our own civilization classes. Teaching contemporary civilization has made such tremendous progress in the last thirty years that French history has often been taken for granted and left to fend for itself, if not overlooked. To be sure, a consensus exists among instructors that the antecedents of current culture must be invoked, and there is good evidence that students in our civilization courses have a strong interest in history which
Transient state isoelectric focusing. Experimental determination of apparent diffusion coefficients in polyacrylamide gels.

Abstract A photoelectric scanning assembly utilizing uv absorption optics and an on-line digital data acquisition and processing system has been used to follow kinetically zone spreading during the defocusing stage (absence of electric field) of transient state isoelectric focusing (TRANSIF) in polyacrylamide gels. Measurement of the variance (σ2) of a diffusing zone as a function of time yields a linear relationship, the slope of which corresponds to the apparent diffusion coefficient (D) of the protein. A linear relationship is also obtained when the logarithm of the apparent diffusion coefficients (logD) are plotted vs acrylamide concentration (T). This relationship can be used to extrapolate D to zero gel concentration. The apparent diffusion coefficient measured in this way is significantly larger than the true diffusion coefficient. The slope of the plot logD vs T, designated CR, is expected to be a measure of molecular size related to the retardation coefficient in polyacrylamide gel electrophoresis.
The Economy of Literacy: How the Supreme Court Stalled the Civil Rights Movement

According to critical race theorists, legal rights in this country have been compromised by the recognition of White identity as having property value. In this article, drawing on these analyses as well as the observations of literacy scholars questioning the outcomes of literacy and education, Catherine Prendergast argues that the designation of literacy and education as "rights" is more rhetorical than real. Prendergast pays close attention to the arguments and court proceedings of three U.S. Supreme Court cases in which the value of literacy and the reality of racial discrimination have both been contested. Through an analysis of these landmark cases — Brown v. Board of Education, Washington v. Davis, and Regents of the University of California v. Bakke—the author deconstructs "the lofty prose equating education with equal opportunity" to uncover the ideologies of literacy that informed these cases. According to Prendergast, "this rhetoric has laid the foundation for the recent legal challenges to affi...
An integral inequality in the stability problem of time-delay systems

An integral inequality is derived, and applied to the stability problem of time-delay systems using discretized Lyapunov functional formulation. As the result, a simpler stability criterion is derived.
Blood Flow Detection And Analysis

The papers presented in this section are a small sample of a gradually evolving area of cardiovascular diagnosis. Blood flow detection using Doppler techniques was originally demonstrated in the late 1950s and early 60s; and although overall progress to date seems to be far behind M-mode echo and 2D imaging clinical applications, more rapid progress appears to be looming on the horizon.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
A Comparison of Element-By-Element Preconditioned Iterative Methods for Solid and Structural Mechanics

Past work with element-by-element (EBE) preconditioned conjugate gradient iterative solution strategies has shown these techniques can be effective for large-scale, three-dimensional calculations in solid and structural mechanics. Significant gains over the profile storage direct solution method traditionally used in implicit finite element codes have been observed for a variety of real engineering analyses, especially in solid mechanics. Structural mechanics applications have proved less successful due to the ill-conditioned linear systems engendered by standard structural discretizations. This lack of robustness has recently motivated reconsideration of Lanczos-based algorithms as alternative iterative drivers. In this paper we compare the relative strengths of the conjugate gradient and Lanczos drivers when coupled with EBE preconditioning. The performance of the two methods is characterized, and compared with direct solution, using a model problem and a number of real engineering meshes. These examples suggest that the conjugate gradient method remains superior for large-scale computation.
Apoprotein B Degradation Is Promoted by the Molecular Chaperones hsp90 and hsp70

Apoprotein B (apoB) is the major protein of liver-derived atherogenic lipoproteins. The net production of apoB can be regulated by presecretory degradation mediated by the ubiquitin-proteasome pathway and cytosolic hsp70. To further explore the mechanisms of apoB degradation, we have established a cell-free system in which degradation can be faithfully recapitulated. Human apoB48 synthesized in vitro was translocated into microsomes, glycosylated, and ubiquitinylated. Subsequent incubation with rat hepatic cytosol led to proteasome-mediated degradation. To explore whether hsp90 is required for apoB degradation, geldanamycin (GA) was added during the degradation assay. GA increased the recovery of microsomal apoB48 ∼3-fold and disrupted the interaction between hsp90 and apoB48. Confirming the hsp90 effect in the cell-free system, we also found that transfection of hsp90 cDNA into rat hepatoma cells enhanced apoB48 degradation. Finally, apoB48 degradation was reconstituted in vitro using cytosol prepared from wild type yeast. Notably, degradation was attenuated when apoB48-containing microsomes were incubated with cytosol supplemented with GA or with cytosol prepared from yeast strains with mutations in the homologues of mammalian hsp70 and hsp90. Overall, our data suggest that hsp90 facilitates the interaction between endoplasmic reticulum-associated apoB and components of the proteasomal pathway, perhaps in cooperation with hsp70.
Sexually Explicit Media on the Internet: A Content Analysis of Sexual Behaviors, Risk, and Media Characteristics in Gay Male Adult Videos

Recent research suggests that viewing sexually explicit media (SEM), i.e., adult videos, may influence sexual risk taking among men who have sex with men. Despite this evidence, very little is known about the content of gay male SEM on the Internet, including the prevalence of sexual risk behaviors and their relation to video- and performer-characteristics, viewing frequency, and favorability. The current study content analyzed 302 sexually explicit videos featuring male same-sex performers that were posted to five highly trafficked adult-oriented websites. Findings revealed that gay male SEM on the Internet features a variety of conventional and nonconventional sexual behaviors. There was a substantial prevalence of unprotected anal intercourse (UAI) (34 %) and was virtually the same as the prevalence of anal sex with a condom (36 %). The presence of UAI was not associated with video length, amateur production, number of video views, favorability, or website source. However, the presence of other potentially high-risk behaviors (e.g., ejaculation in the mouth, and ejaculation on/in/rubbed into the anus) was associated with longer videos, more views, and group sex videos (three or more performers). The findings of high levels of sexual risk behavior and the fact that there was virtually no difference in the prevalence of anal sex with and without a condom in gay male SEM have important implications for HIV prevention efforts, future research on the role of SEM on sexual risk taking, and public health policy.
High-energy laser weapons: technology overview

High energy laser (HEL) weapons are ready for some of today’s most challenging military applications. For example, the Airborne Laser (ABL) program is designed to defend against Theater Ballistic Missiles in a tactical war scenario. Similarly, the Tactical High Energy Laser (THEL) program is currently testing a laser to defend against rockets and other tactical weapons. The Space Based Laser (SBL), Advanced Tactical Laser (ATL) and Large Aircraft Infrared Countermeasures (LAIRCM) programs promise even greater applications for laser weapons. This technology overview addresses both strategic and tactical roles for HEL weapons on the modern battlefield and examines current technology limited performance of weapon systems components, including various laser device types, beam control systems, atmospheric propagation, and target lethality issues. The characteristics, history, basic hardware, and fundamental performance of chemical lasers, solid state lasers and free electron lasers are summarized and compared. The elements of beam control, including the primary aperture, fast steering mirror, deformable mirrors, wavefront sensors, beacons and illuminators will be discussed with an emphasis on typical and required performance parameters. The effects of diffraction, atmospheric absorption, scattering, turbulence and thermal blooming phenomenon on irradiance at the target are described. Finally, lethality criteria and measures of weapon effectiveness are addressed. The primary purpose of the presentation is to define terminology, establish key performance parameters, and summarize technology capabilities.
Antiracist Pedagogy: Definition, Theory, and Professional Development

Abstract The purpose of this paper is to define Antiracist Pedagogy and establish it within the sociological framework of Critical Theory. Antiracist Pedagogy is a paradigm located within Critical Theory utilized to explain and counteract the persistence and impact of racism. This paper indicates the need for the establishment of Antiracist Pedagogy within the school curriculum as well as the necessary professional development required to implement Antiracist Pedagogy effectively.
Light-scattering contributions to the circular dichroism of particulate systems☆

Abstract A detailed analysis of the effects to be expected from light scattering upon circular dichroism is presented. This analysis is based upon an extension of the classical treatment of Rayleigh scattering to include the asymmetric interaction of an optically active chromophore with the incident light. It is concluded that distortions resulting from light scattering are very small and are not expected to account for the characteristic “red-shifted” features of membrane spectra.
Influence of Estrus Detection on Days Open in Dairy Herds

Data from 10 herds on a herd reproductive status program supported estimates of lost reproductive days per cow per year due to conception failure and missed heat as 23 and 10 days. The corresponding estimates from Ohio Dairy Herd Improvement were 14.7 and 40.3 days. The correlation within the 10 herds between days lost due to failure to conceive and total days open was .38 and between days lost due to missed heats and total days open .92.
Constitutive laws for thin plates of power-law materials

Abstract With the Kirchhoff assumption, a stress resultant constitutive law as a function of the kinematic variables for thin plates of power-law hardening materials is derived under proportional straining conditions. Also, in analogy to the J z deformation plasticity and incremental plasticity theory, a flow rule, based on the constitutive law, to describe the elastic plastic behavior of the plate is proposed. The constitutive behavior of the plates subjected to uniaxial combined membrane force and bending moment is examined in detail and the results are compared with those for the corresponding clastic plastic materials using the through-the-thickness integration method. The yield surfaces for power-law materials are constructed and the formation of vertiees on the yield surfaces for perfectly plastic materials under such a loading condition is clearly demonstrated.
How ocean ridges affect large‐scale ocean circulation

Driving the flow of heat and nutrients around the ocean is the meridional overturning circulation, a large-scale current system that in the Atlantic Ocean carries warm surface waters northward and cold, dense water to the south along the bottom of the ocean. An important leg of this journey is the conversion of light warm water into North Atlantic Deep Water (NADW), which occurs along the coasts of Greenland and Labrador, Canada. The temperature and density profile of the ocean is important for climate and ecological systems, so understanding any physical features that may impinge on the properties of NADW, such as ocean ridges, is particularly important. Using experiments in a laboratory water tank, Stewart et al. identified how a ridge could affect the circulation patterns in a model ocean. The authors imposed temperature and heat flux gradients on the surface of the ocean analogue and tracked how differences in ridge size, shape, and location affected the temperature and density stratification. They found that when the ridge is sufficiently shallow, such that the depth of the water between the top of the ridge and the surface of the ocean is less than twice as deep as the ocean thermocline—a near-surface band of the ocean in which water temperature decreases rapidly with depth—the ridge can significantly affect downstream properties. The authors found that when the deep water is forced up and over a shallow ridge, it tends to mix with the warmer water of the thermocline, increasing the average temperature and density stratification of water downstream from the ridge. (Journal of Geophysical Research-Oceans, doi:10.1029/2011JC006980, 2011
A 4-Year Longitudinal Investigation of the Processes by Which Parents and Peers Influence the Development of Early Adolescent Girls’ Bulimic Symptoms

Bulimic symptoms are fairly common among adolescent girls, and the dual pathway model outlines one possible etiological chain leading to bulimic symptoms. The present study seeks to longitudinally examine the pathways proposed by this model while focusing on the relative contribution of parents and peers (via direct encouragement or pressure to be thin and indirect discussion of dieting). Four years of self-report data were collected from 85 early adolescent girls during fifth through eighth grades. Results indicated that mothers, fathers, and peers each played an important role in the development of girls’ bulimic symptoms by affecting their body dissatisfaction, which was related to later dieting behaviors, depressive symptoms, and bulimic symptoms. Furthermore, results suggested that peers were a stronger influence than mothers and fathers. The authors conclude that both parents and peers play important roles in girls’ development of bulimic symptoms, and future work should especially include peers.
Thermal degradation of PVC in the presence of polystyrene

The thermal degradation of poly(vinyl chloride) (PVC) and blends of PVC with polystyrene has been studied using thermogravimetric analysis coupled to Fourier transform infrared spectroscopy. The degradation of PVC commences at weak links by an ionic pathway, but there is evidence to suggest the presence of a radical pathway at high temperatures. While there is some chemical interaction between PVC and polystyrene, the principal mode of stabilization is a physical process.
Focus Issue: From Genes to Tissues

Science and Science ’s STKE highlight the molecular mechanisms that control the development of complex organisms. Science emphasizes the evolution of the eye and heart and the Hox gene family, whereas articles at Science 9s STKE highlight the regulatory mechanisms by which gene expression profiles are established to allow complex structures to form.
Dynamic Response of Power Transformers Under Axial Short Circuit Forces Part II - Windings and Clamps as a Combined System

This paper is in continuation of Part I. It discusses the dynamic axial risponse of the total transformer system made up of the windings and the clamping structure. The numerical solution presented here accounts for all nonlinearities in the system. The viscoelastic model for representing the dynamic stiffness of the oil-permeated insulation is investigated in detail. Good comparisons between the calculated values and the test values on a 10 MVA transformer support the models and methods developed here.
A case of a lower pole renal calculus managed with percutaneous nephrolithotomy

In this Case Study, Tseng and Matlaga report on a 50-year-old man with a 1.5 cm lower pole renal calculus who was successfully treated with percutaneous nephrolithotomy. They discuss the management options for patients presenting with lower pole calculi and highlight the need for studies evaluating quality-of-life outcomes for the different approaches. Background A 50-year-old man presented to an outpatient urology clinic with left-sided flank pain. He had received treatment for a left renal pelvis calculus 5 years earlier; shock wave lithotripsy had been unsuccessful and ureteroscopic laser lithotripsy had left the patient with a 2 mm residual stone fragment. The fragment was deemed clinically insignificant, and the patient remained asymptomatic without any further follow-up. Investigations Physical examination, CT of the abdomen and pelvis, and complete metabolic evaluation. Diagnosis Left lower pole renal calculus and idiopathic hypercalciuria. Management The patient was counseled about his treatment options, and he elected to undergo percutaneous nephrolithotomy. After a single-stage procedure, CT confirmed a stone-free state. The patient was administered thiazide therapy and dietary counseling to treat his hypercalciuria. This condition resolved, and the patient remained stone-free 1 year after treatment.
Postphenomenological Re-embodiment

The phenomenological tradition has had a long interest in embodiment, and bodily experience beyond the confines of the “skinbag” body. Here I respond to Helena De Preester’s analysis of different types of protheses: limb, perceptual, cognitive. In her paper “Technology and the body: the (im)possibilities of re-embodiment”, she wants to make finer distinctions between extensions and incorporations. Today’s hi-tech developments make this refinement necessary and possible. I respond to the three levels or types of prostheses taking note of the increasing difficulty at each level and express certain worries about cognitively framed notions of bodily experience.
Service outcomes in physical and sexual abuse cases : A comparison of child advocacy center-based and standard services

Child Advocacy Centers (CACs) were developed to improve on child abuse investigative services provided by child protective service (CPS) agencies. However, until very recently, there has been little research comparing CAC-based procedures and outcomes to those in CPS investigations not based in CACs. The current study tracked 76 child abuse cases that were reported to authorities and investigated through either a private, not-for-profit CAC or typical CPS services in a mid-south rural county. Comparisons between CAC and CPS cases were made in terms of involvement of local law enforcement in the investigation, provision of medical exams, abuse substantiation rates, mental health referrals, prosecution referrals, and conviction rates. Analyses revealed higher rates of law enforcement involvement, medical examinations, and case substantiation in the CAC-based cases compared to the CPS cases. Despite limitations due to sample size and nonrandomization, this study found preliminary support for the assumptions underlying the establishment of CACs. Language: en
Radiative Impact on Tropopause Polar Vortices over the Arctic

AbstractTropopause polar vortices (TPVs) are commonly observed, coherent circulation features of the Arctic with typical radii as large as approximately 800 km. Intensification of cyclonic TPVs has been shown to be dominated by infrared radiation. Here the hypothesis is tested that while radiation alone may not be essential for TPV genesis, radiation has a substantial impact on the long-term population characteristics of cyclonic TPVs.A numerical model is used to derive two 10-yr climatologies of TPVs for both winter and summer: a control climatology with radiative forcing and an experimental climatology with radiative forcing withheld. Results from the control climatology are first compared to those from the NCEP–NCAR reanalysis project (NNRP), which indicates sensitivity to both horizontal grid resolution and the use of polar filtering in the NNRP. Smaller horizontal grid resolution of 60 km in the current study yields sample-mean cyclonic TPV radii that are smaller by a factor of ~2 compared to NNRP, a...
Stark effect and single-electron charging in silicon nanocrystal quantum dots

In this article, we investigate numerically the electronic structure of semispherical nanocrystals in quantum-dot based flash memory devices. We model three different sizes of nanocrystals with diameters of 125, 70, and 50 A by solving self-consistently a system of three-dimensional (3D) Kohn–Sham and Poisson equations. We show that the unique combination of symmetries in the bandstructure and the 3D confinement geometry produce Stark effects with energy-level crossings in the nanocrystals. We also show that the quantum states in large nanocrystals (125 A diameter) respond markedly different to the applied control-gate electric field compared to the smaller nanocrystals (diameter <70 A). Finally, we simulate single-electron charging and obtain the addition energy spectrum of the 125-A-diam nanocrystal.
Modification of the Psychosocial Assessment of Candidates for Transplantation (PACT) Improves Risk Classification and Prediction of Hospital Readmission of MCS Patients

Purpose We previously demonstrated that the PACT falsely characterized some patients (pts) considered for MCS therapy as high risk. We developed and evaluated a new MCS-specific PACT; thus, the purpose of this study was to examine the sensitivity and specificity of this revised instrument to classify MCS pts. Methods and Materials PACT domains were re-written to reflect psychosocial criteria influencing social success defined as a reliable support system, discharge on schedule, and no social re-admissions. Areas of concern for HT candidates were eliminated and social support was emphasized. A social worker, blinded to outcomes, re-scored previously studied pts with the revised instrument. mPACT and PACT scores were then compared. Team members were surveyed: Was this pt a social success? Answers were assigned a value [no=0, yes=1] to determine a social success score. Success was considered a mean score >.5. Results 48 pts (72% men, 44% AA, 50.4 yrs) supported on MCS for 274 days were evaluated. The sensitivity of a score of 17 to identify a social success was .97 and the specificity was .56. The PPV was .97 and NPV was .56, compared to .86 and .44 respectively, for the PACT. A reclassification table was developed to assess the difference in risk stratification of the mPACT compared to the PACT. Net reclassification showed 19% improvement in risk stratification by the mPACT. Five of the 9 patients falsely categorized as high risk by the original PACT score were appropriately re-categorized as low risk with the mPACT. Patients with an mPACT score Conclusions By eliminating risk factors that do not have the same bearing on MCS outcome as HT and emphasizing areas of social support, we appropriately re-classified patients as acceptable risk who had been incorrectly considered high risk by the PACT. The mPACT score showed improved performance and warrants prospective validation.
Suppression of immunoglobulin production in normal human blood: characterization of the cells responsible and mediation by a soluble T lymphocyte-derived factor.

Abstract The nature of the cells capable of inhibiting pokeweed mitogen-induced peripheral blood B-lymphocyte immunoglobulin production was investigated and shown to involve two separate cell populations. A T-lymphocyte subpopulation mediating suppression of immunoblobulin synthesis was characterized by its sensitivity to inhibitors of DNA synthesis (irradiation and mitomycin C) relative to helper T lymphocytes. Generation and activity of these suppressor T lymphocytes was not directly related to the number of macrophages present nor were these T suppressors removed on nylon wool columns. Supernatant culture fluid derived from pokeweed mitogen-stimulated suppressor T lymphocytes was capable of mediating inhibition of immunoglobulin synthesis. All major immunoglobulin classes (IgG, IgM, and IgA) were suppressed in allogeneic as well as autochthonous combinations. A macrophage population was also shown to be capable of inhibiting B-lymphocyte production of immunoglobulin. Removal of adherent or phagocytic cells abolished the suppression of immunoglobulin observed when increasing number of B-cell fractions were cultured in the presence of these phagocytic/adherent cells. Thus, suppressor T lymphocyte and suppressor macrophage populations normally exist in human peripheral blood and their overproliferation or overactivation may lead to some of the states of immunodeficiency observed in humans.
Platelet activating factor-stimulated formation of inositol triphosphate in platelets and its regulation by various agents including Ca2+, indomethacin, CV-3988, and forskolin.

Abstract When myo-2-[3H]inositol-labeled rabbit platelets were stimulated with 1 × 10-9 m sn-3-AGEPC (platelet activating factor) for 5 s, the levels of [3H]inositol monophosphate (IP), [3H]inositol diphosphate (IP2), and [3H]inositol triphosphate (IP3) increased about 1.5-, 3-, and 5-fold, respectively. Formation of these inositol polyphosphates was strikingly independent of extracellular Ca2+. Inactive analogs of sn-3-AGEPC, i.e., lysoGEPC and stereoisomer sn-1-AGEPC, did not cause production of any inositol polyphosphate. Pretreatment of platelets with indomethacin (5 μ m ) had little effect on this phenomenon. On the other hand, a platelet activating factor antagonist, CV-3988, blocked the AGEPC-stimulated production of radioactive IP, IP2, and IP3. Similarly forskolin, an activator of adenylate cyclase, at 5 μ m or above completely abolished AGEPC-induced aggregation, [3H]serotonin secretion, and formation of [3H]inositol polyphosphates. In the light of the emerging role of AGEPC in inflammation, hypotension, and other cardiovascular processes, studies with platelets reported here indicate that forskolin could be a useful tool for manipulating AGEPC responses. It is further concluded that AGEPC-induced formation of inositol polyphosphate is an early response “specific” to AGEPC, mediated via extracellular Ca2+-independent phosphoinositide phosphodiesterase, and could play a role in intracellular Ca2+ mobilization and platelet shape change.
High dynamic range suppressed-bias microwave photonic links using unamplified semiconductor laser source

Microwave photonic (MWP) links with a low noise figure and high dynamic range are required for antenna remoting, radio-over-fiber (RoF), and other advanced applications. MWP links have recently been demonstrated with noise figures approaching 3 dB, without any electrical preamplification, by using low-noise high-power laser sources in conjunction with efficient optical intensity modulators and high-power photodetectors [1]. An alternate approach to noise figure reduction, suitable for sub-octave links, is based on using a high-power laser source and shifting the bias point of an external optical intensity modulator to reduce the average photocurrent and suppress excess link noise [2]. Here, we report the performance of a novel slab-coupled optical waveguide external-cavity laser (SCOWECL) in a suppressed-bias MWP link [3]. We compare the performance of this link with a suppressed-bias link using a source comprising a commercial-off-the-shelf (COTS) laser and erbium-doped fiber amplifier (EDFA) and show that MWP links built using SCOW-based emitter technology offer superior performance due to the small-form factor, high-efficiency, low-noise, and high power laser source.
A taxonomy and survey on Green Data Center Networks

Abstract Data centers are growing exponentially (in number and size) to accommodate the escalating user and application demands. Likewise, the concerns about the environmental impacts, energy needs, and electricity cost of data centers are also growing. Network infrastructure being the communication backbone of the data center plays a pivotal role in the data center’s scalability, performance, energy consumption, and cost. Research community is endeavoring hard to overcome the challenges faced by the legacy Data Center Networks (DCNs). Serious efforts have been made to handle the problems in various DCN areas. This survey presents significant insights to the state-of-the-art research conducted pertaining to the DCN domain along with a detailed discussion of the energy efficiency aspects of the DCNs. The authors explored: (a) DCN architectures (electrical, optical, and hybrid), (b) network traffic management and characterization, (c) DCN performance monitoring, (d) network-aware resource allocation, (e) DCN experimentation techniques, and (f) energy efficiency. The survey presents an overview of the ongoing research in the broad domain of DCNs and highlights the challenges faced by the DCN research community.
Surface modification of biodegradable polyesters with fatty acid conjugates for improved drug targeting

We describe a general method for incorporating target ligands into the surface of biocompatible polyester poly(lactic-co-glycolic acid) (PLGA) 50/50 materials using fatty acids. Avidin-fatty acid conjugates were prepared and efficiently incorporated into PLGA. Avidin was chosen as an adaptor protein to facilitate the attachment of a variety of biotinylated ligands. We show that fatty acid preferentially associates with the hydrophobic PLGA matrix, rather than the external aqueous environment, facilitating a prolonged presentation of avidin over several weeks. We successfully applied this approach in both microspheres encapsulating a model protein, bovine serum albumin, and PLGA scaffolds fabricated by a salt-leaching method. Because of its ease, generality and flexibility, this strategy promises widespread utility in modifying the surface of PLGA-based materials for applications in drug delivery and tissue engineering.
Economics of the Golden Mean: A Preliminary Enquiry

The importance of the golden mean or moderation in daily human life has been advocated almost universally by all the great teachers of the world. In the sphere of economics, however, it seems to have been largely ignored. Determines whether preliminary evidence can be found to give some support to the golden mean in economics. Uses the data for the 50 states of the USA, and the preliminary finding indicates that ideologically moderate (golden mean) states do seem to perform better than conservative states. But liberal states fare still better. One possible explanation for this is that liberal states in the USA are really moderates in the ideological spectrum of the world.
Tyrosine mutant helps define overlapping CD bands from fd gene 5 protein.nucleic acid complexes.

We used a mutant gene 5 protein (g5p) to assign and interpret overlapping CD bands of protein nucleic acid complexes. The analysis of overlapping protein and nucleic acid CD bands is a common challenge for CD spectroscopists, since both components of the complex may change upon binding. We have now been able to more confidently resolve the bands of nucleic acids complexed with the fd gene 5 protein by exploiting a mutant gene 5 protein that has an insignificant change in tyrosine optical activity at 229 nm upon binding to nucleic acids. We have studied the interactions of the mutant Y34F g5p (Tyr-34 substituted with phenylalanine) with poly[r(A)], poly[d(A)], and fd single-stranded DNA (ssDNA). Our results showed the following: (1) The 205-300 nm spectrum of poly[r(A)] saturated with the Y34F mutant (P/N = 0.25) was essentially the sum of the spectra of poly[r(A)] at a high temperature plus the spectrum of the free protein, except for a minor negative band at 257 nm. (2) The spectra of poly[d(A)] and fd ssDNA saturated with the mutant protein at a P/N = 0.25, minus the spectra of the free nucleic acids at a high temperature, also essentially equaled the spectrum of the free protein in the 205-245 nm region. (3) While the overall secondary structure of the Y34F protein did not change upon binding to any of these nucleic acids, there could be changes in the environment of individual aromatic residues. (4) Nucleic acids complexed with the g5p are unstacked (as if heated) and (in the cases of the DNAs) perturbed as if part of a dehydrated double-stranded DNA. (5) Difference spectra revealed regions of the spectrum specific for the particular nucleic acid, the protein, and whether g5p was bound to DNA or RNA.
Somatotopic organization in the spinal trigeminal nucleus, the dorsal column nuclei and related structures in the rat.

The medulla of the anesthetized rat was explored with with fine (25.4 μ) wire electrodes from C1 rostrally to the cerebellar penduncles. Concurrently, the body surface and the buccal cavity were mechanically stimulated with delicate probes. Descriptions of peripheral fields and characteristics of evoked discharges were recorded. Histological evidence revealed that the dorsal column nuclei yeilded responses to stimulation of the limbs, trunk, posterior face and pinna. The spinal trigeminal nucleus indicated an input from the face and from buccal cavity components, while the solitary nucleus disclosed an input originating in the tongue and, less often, in other oral structures. In addition, loci in adjacent portions of the reticular formation gave responses to mild stimulation of many peripheral regions. Most of the body projected to every level of the medulla studied. The projection was typically homolateral, and fields of many sizes were represented throughout the longitudinal extent of each nucleus. The amount of bulbar tissue devoted to any region of the body appeared to be related to the innervation density of that region. The results support the concept that the nuclei can be regarded together as a functional unit which resembles the primary tactile systems of the thalamus and the cortex in somatotopic organization.
Identification of Mistuning Characteristics of Bladed Disks From Free Response Data— Part II

The focus of the present two-part investigation is on the estimation of the dynamic properties, i.e., masses, stiffnesses, natural frequencies, mode shapes and their statistical distributions, of turbomachine blades to be used in the accurate prediction of the forced response of mistuned bladed disks. As input to this process, it is assumed that the lowest natural frequencies of the blades alone have been experimentally measured, for example in a broach block test. Since the number of measurements is always less than the number of unknowns, this problem is indeterminate in nature. In this second part of the investigation, the maximum likelihood method (ML) will first be revisited and a thorough assessment of its reliability in a wide variety of conditions, including the presence of measurement noise, different distributions of blade structural properties, etc., will be conducted. Then, a technique that provides a bridge between the two identification methods introduced in Part I, i.e., the random modal stiffnesses (RMS) and maximum likelihood (ML) approaches, will be presented. This technique, termed the improved random modal stiffnesses (IRMS) method is based on the maximum likelihood concepts but yields a mistuning model similar to that of the random modal stiffnesses technique. Finally, the accuracy of the RMS, ML, and IRMS methods in predicting the forced response statistics of mistuned bladed disks will be investigated in the presence of close blade alone natural frequencies.
Leukemia and exposure to 1,3-butadiene, styrene and dimethyldithiocarbamate among workers in the synthetic rubber industry.

Abstract This study evaluated relations between exposure to 1,3-butadiene (BD), styrene (STY) and dimethyldithiocarbamate (DMDTC) and mortality from leukemia among synthetic rubber industry workers. Subjects were 13 130 men employed for at least 1 year during 1943–1991 at any of six plants that manufactured synthetic rubber. Death certificates and medical records identified workers with leukemia. Cumulative exposure estimates were based on plant- and time period-specific process and task characteristics, linked to subjects’ work histories. Poisson regression estimated relative rates (RRs) for workers exposed to each agent compared to unexposed workers. Leukemia (N=59) was positively associated with BD ppm-years (RRs of 1.0, 1.2, 2.0 and 3.8, for exposures of 0, >0– 0– 0– 100 ppm than for ppm-years due to lower concentrations. BD and DMDTC, but not STY, were positively associated with leukemia in multivariable analyses. The independent effect of each agent was difficult to evaluate because of correlations with other agents and imprecision.
Genetic analysis of structure and function in phage T4 tRNASer

Abstract We have determined the nucleotide sequences of 55 spontaneous mutations that inactivate a suppressor gene of phage T4 tRNASer. Most of the mutations caused substitutions or deletions of single nucleotides at 18 different positions in the tRNA. Two of three mutations that allowed the synthesis of mature tRNA had nucleotide substitutions at the junction of the dihydrouridine and anticodon stems, suggesting that this region of tRNASer is important for aminoacylation. The third mutation that synthesized tRNA had a nucleotide deletion in the anticodon loop, which presumably affected the translational capacity of the tRNA. We also sequenced 58 spontaneous reversion mutations derived from strains with the inactive suppressor genes. Some of these regenerated the initial tRNA sequence, while others generated a second-site mutation in the tRNA. These second-site mutations restored helical base-pairings to the tRNA that had been eliminated by the initial mutations. The new base-pairings involved G · C and A · U, and the A · C wobble pair at certain positions in the tRNA. This finding establishes the existence of A · C wobble pair in tRNA helices.
Legionnaires' Disease at a Community Hospital

Excerpt To the editor: In response to your April 1979 symposium on Legionnaire's disease (1), I wish to describe the services organized at our 375-bed community hospital for the diagnosis of that i...
Relationships between students’ learning and their participation during enactment of middle school algebra tasks

This study examines a sequence of four middle school algebra tasks through their enactment in three teachers’ classrooms. The analysis centers on the cognitive demand—the kinds of thinking processes entailed in solving the task—and the participatory demand—the kinds of verbal contributions expected of students—of the task as written in the instructional materials, as set up by the three teachers, and as discussed by the teachers and their students. Relationships between the nature of the task enactments and students’ performance on a pre- and post-test are explored. Findings include the fact that the enacted tasks differed from the written tasks with regard to both the cognitive demand and the participatory demand, which related to students’ lack of success on the post-test. Specifically, cognitive demand declined in the enacted curriculum at different points for different classes, and the participatory demand during enactment tended to involve isolated mathematical terms rather than students verbally expressing mathematical relations.
I never had a mentor: Reflections of a chicano sociologist

By tracing the career path of a senior Chicano sociologist, this article attempts to gain insights into the problems and dilemmas faced by minority scholars in earlier stages of their careers. Tensions between the demands of a professional identity as a sociologist, on the one hand, and a personal identity as a Chicano, on the other, are isolated and discussed. It is suggested that this dynamic tension between professional and personal demands, coupled with expanding career opportunities and the emergence of Chicano Studies as an academic discipline, gave impetus to the development of an indigenous Chicano sociology that challenged traditional sociological paradigms and was grounded in Chicano culture and world view.
Molecular cloning and nucleotide sequence of a new P450 gene, CYP319A1, from the cattle tick, Boophilus microplus

We have isolated and sequenced a novel P450 gene (CYP319A1) from the cattle tick, Boophilus microplus. The CYP319A1 cDNA encodes a protein of 531 amino acids with an estimated molecular weight of 60.9 k. It contains all highly conserved motifs characteristic of P450 enzymes. Comparison of deduced amino acid sequence with other CYP members shows that the CYP319A1 is more closely related to CYP4 family, but its overall identity to the CYP4 family is less than 40%. Therefore, it was assigned to a new P450 family by the P450 nomenclature committee. A pseudogene which shares high homology with the CYP319A1 was identified. Analysis of genomic sequence of the pseudogene indicated that the pseudogene contains two additional DNA inserts in the coding region, which disrupt the open reading frame. RT-PCR analysis showed that CYP319A1 is expressed in both susceptible and acaricide-resistant ticks.
Fractionation of Multiwalled Carbon Nanotubes by Cascade Membrane Microfiltration

Multiwalled carbon nanotubes were purified and size-separated by a multistep microfiltration process through a sequence of track-etched polycarbonate membranes of various pore sizes in both dead-ended and cross-flow mode. For this cascade microfiltration, the electric arc derived raw multiwalled samples were suspended in an aqueous solution of sodium dodecyl sulfate in deionized water. By examining the deposits on the membrane surfaces and in the permeate suspensions with scanning electron microscopy and atomic force microscopy, the nanotube fractionation was confirmed and analyzed. These scanning techniques showed that the components of the crude sample, which included carbon nanotubes, polyhedral nanoparticles, and large aggregates, were separated from each other during the filtration. In addition, fractionation of the multiwalled carbon nanotubes according to length was possible.
Family-of-Origin, Relationship Self-Regulation, and Attachment in Marital Relationships

Within the framework of the vulnerability-stress adaptation model, we created an actor partner interdependence model to assess the relationships between negative family-of-origin experiences and relationship self-regulation, a type of relationship maintenance, and the mediating potential of partner attachment behaviors. We analyzed data from 261 heterosexual married couples in matched-pair sets from the Relationship Evaluation database (see www.relate-institute.org ). Results indicated that negative family-of-origin experiences were positively associated with relationship self-regulation and secure attachment behaviors. We also found that attachment behaviors mediated the relationship between negative family-of-origin experiences and relationship self-regulation. These findings demonstrate particular clinical relevance for strengthening attachment in couples therapy.