cssi/SciSciGPT-SciSciNet huggingface dataset:
Transmembrane helix tilting and ligand-induced conformational changes in the lactose permease determined by site-directed chemical crosslinking in situ

The N-terminal six transmenbrane helices (N6) and the C-terminal six transmembrane helices (C6) of the lactose permease of Escherichia coli, each with a Cys residue, were co-expressed independently, and crosslinking was studied. Proximity of paired Cys residues in helices II (position 49, 52, 53, 56, 57, 60, 63 or 67) and VII (position 227, 230, 231, 234, 238, 241, 242 or 245) or XI (position 350, 353, 354, 357, 361 or 364) was examined by using two homobifunctional thiol-specific crosslinking agents of different lengths (6 or 10 A). The results demonstrate that a Cys residue placed in the periplasmic half of helix II (position 49, 52, 53 or 57) crosslinks to Cys residues in the periplasmic half of helix VII (position 241, 242 or 245). In contrast, no crosslinking is evident with paired-Cys residues in the cytoplasmic halves of helices II (position 60, 63 or 67) and VII (position 227, 230, 231, 234 or 238). Remarkably, a Cys residue in the cytoplasmic half of helix II (position 60, 63 or 67) crosslinks with a Cys residue in the cytoplasmic half of helix XI (position 350, 353 or 354), while paired-Cys residues at positions in the periplasmic halves of the two helices do not crosslink. Therefore, helix II is tilted in such a manner that the periplasmic end is close to helix VII, and the cytoplasmic end is close to helix XI. Furthermore, ligand-binding alters the crosslinking efficiency of paired-Cys residues in helices II and VII or XI, indicating that both interfaces are conformationally active. The results are consistent with the conclusion that ligand-binding induces a scissors-like movement of helices II and VII that increases interhelical distance by 3 to 4 A at the periplasmic ends and decreases the distance by 3 to 4 A at the approximate middle of the two transmembrane helices.
Generation of human hybridomas producing migration inhibitory factor (MIF) and of murine hybridomas secreting monoclonal antibodies to human MIF.

Abstract Human T-cell hybridomas were established by hybridization of concanavalin A (Con A)-stimulated human peripheral blood T lymphocytes with cells from a 6-thioguanine-resistant, aminopterin-sensitive mutant line designated CEM-WH4, derived from the continuously growing human T cell line, CEM. High levels of MIF activity were demonstrated in the supenatants of two hybridoma lines, T-CEMA and T-CEMB but not of CEM-WH4 when stimulated with phorbol myristate acetate and phytohemagglutinin. In comparison, MIF derived from Con A-stimulated peripheral blood mononuclear cells showed 100 times less activity. Upon isoelectrofocusing, MIF activity of T-CEMB was found exclusively between pH 4.6 and 5.3 whereas MIF derived from T-CEMA showed heterogeneity with a major peak of MIF recovered at pH 4.6–5.3 and a minor peak at pH 2.4–3.3. These molecules, however, were all found to have an apparent MW of 68,000 and were resistant to trypsin. Most of these characteristics are in accordance with second day pH 3- and pH 5-MIF derived from peripheral blood mononuclear cells. When spleen cells from BALB/c mice immunized with T-CEMB-MIF were used to fuse with NS-1 mouse myeloma cells, nine hybridomas secreting antibodies to human MIF were obtained. Clone D112 which demonstrated the highest MIF-neutralizing activity was found to neutralize MIF derived from T-CEMA, peripheral blood mononuclear Cells, and a T cell line, Mo.
Transient Heat Transfer in Extended Surfaces

This paper attempts to provide a comprehensive, coherent, and methodical review of the existing literature on the transient performance of extended surfaces (fins). With the exception of very few experimental studies, the work described is theoretical involving either analytical approaches or numerical computations. For both longitudinal and radial convecting fins, the shapes analyzed include fins of rectangular, trapezoidal, concave parabolic, and convex parabolic profiles. The boundary conditions considered are those of time-dependent base temperature or time-dependent base heat flow, or time-dependent temperature of the fluid on the unfinned side of the primary surface. Other studies discussed consider the transient responses of radiating and convecting-radiating fins, fins with stochastic base temperature and fins in which conduction, natural convection, and radiation are coupled. The paper also provides an in-depth consideration of two-dimensional analyses of a cylindrical spine (pin fin) and a composite longitudinal fin. All of the important results pertaining to the transient effect in extended surfaces are presented and these effects are illustrated with several examples. The paper concludes with an attempt to identify future investigative efforts.
Effect of Dihydrocholesterol and β-Sitosterol on Cholesterol Atherosclerosis in Rabbits

While dihydrocholesterol lowered total plasma cholesterol in the rabbit, it did not promote the regression of either the aorta lipid fractions or plaque areas in atherosclerotic animals. A comparative study of the toxicities of β-sitosterol and dihydrocholesterol disclosed that dihydrocholesterol, fed for a 7 month period, resulted in aorta plaque formation and caused the development of liver cirrhosis. On the other hand, β-sitosterol produced no toxic effects.
Tutorial on slowly diffracting beams for radar applications

A variety of novel solutions of the homogeneous free space wave equation and Maxwell's equations that predict a much slower energy decay than the observed classical 1/R squared far-field behavior of an electromagnetic wave from a finite source have appeared in the literature. Some of the more well publicized solutions are: electromagnetic missiles, electromagnetic directed energy pulse trains, Bessel beams, and electromagnetic bullets. We examine some of these issues via a tutorial examination of the underlying physics behind the slowly diffracting behavior of these localized propagating electromagnetic waveforms using electromagnetic engineering concepts that are familiar to radar engineers. We also investigate concepts that would be relevant to developing a radar which employed any of these localized electromagnetic energy forms such as the 'near-field' and 'far-field' behavior of these solutions, and any unique source requirements.
Stability of the laminar mixing of two parallel streams with respect to supersonic disturbances

The stability with respect to ‘supersonic’ disturbances of the laminar mixing of two parallel streams of a compressible fluid is studied. For locally supersonic disturbances there will be waves propagating outward from the mixing layer. The numerical results show that the flow is generally unstable with respect to supersonic disturbances, although the amplification rate is smaller than that for subsonic disturbances. The flow is more unstable at lower Mach number, and the increase of the angle between the disturbance wave-number vector and the principal flow direction tends to increase the instability.
Progressive determination of cell fates along the dorsoventral axis in the sea urchin Heliocidaris erythrogramma

In the direct-developing sea urchinHeliocidaris erythrogramma the first cleavage division bisects the dorsoventral axis of the developing embryo along a frontal plane. In the two-celled embryo one of the blastomeres, the ventral cell (V), gives rise to all pigmented mesenchyme, as well as to the vestibule of the echinus rudiment. Upon isolation, however, the dorsal blastomere (D) displays some regulation, and is able to form a small number of pigmented mesenchyme cells and even a vestibule. We have examined the spatial and temporal determination of cell fates along the dorsoventral axis during subsequent development. We demonstrate that the dorsoventral axis is resident within both cells of the two-celled embryo, but only the ventral pole of this axis has a rigidly fixed identity this early in development. The polarity of this axis remains the same in half-embryos developing from isolated ventral (V) blastomeres, but it can flip 180° in half-embryos developing from isolated dorsal (D) blastomeres. We find that cell fates are progressively determined along the dorsoventral axis up to the time of gastrulation. The ability of dorsal half-embryos to differentiate ventral cell fates diminishes as they are isolated at progressively later stages of development. These results suggest that the determination of cell fates along the dorsoventral axis inH. erythrogramma is regulated via inductive interactions organized by cells within the ventral half of the embryo.
The role of water in cooling ignimbrites

Abstract A summary of observational literature on ignimbrites provides the basis for the development of a two-dimensional numerical model of ignimbrite cooling processes. Factors include emplacement conditions, post-emplacement processes, and the nature and timing of interactions with water during cooling. The model uses the multiphase finite element heat and mass transfer (FEHM) code, which has been enhanced to handle conditions up to 1500 °C. The instantaneous emplacement of a 750 °C ignimbrite with internal gas pressures of up to 0.5 MPa (lithostatic) has a great effect on the variably saturated substrate. A water table present within a few tens of meters of the base of the ignimbrite produces a region of high pressure and temperature that exists for about 20 years, driving vapor upward through the ignimbrite as diffuse flow and in gas escape structures and enhancing cooling at the base of the ignimbrite. Variations in initial gas pressure between atmospheric and lithostatic conditions have little effect on the thermal evolution. The results of the numerical modeling of 20- and 40-m-thick ignimbrites indicate that, even for moderate pore water saturations in the substrate, vaporization and resultant pressurization may exceed lithostatic confining pressures in the upper substrate and basal ignimbrite, and explosive pressure release may occur, resulting in the development of discrete fumarole conduits or phreatic explosions. The likelihood for explosive pressure release appears to be greater when the nominal ignimbrite thickness is on the order of the depth of a buried valley. The pressure buildup is enhanced by the geometry of the ignimbrite–substrate interface, especially at convex corners such as on the edges of a buried valley. The boiling zones at the top and bottom of a cooling ignimbrite involve the development of a heat-pipe, which provides an efficient means of transporting heat from the superheated tephra out tens of meters into the ambient environment. The predicted temporal evolution of temperature, pressure, and vapor flow in a 40-m ignimbrite support the conceptual model of degassing, welding and compaction, devitrification, and alteration occurring concomitantly in the first several years after emplacement and driven in part by production and migration of meteoric steam. This vapor flowing through the ignimbrite matrix at 5×10−5 kg s−1 in the first 10 years enhances devitrification in any part of the ignimbrite above the base in nonwelded deposits. In the case where welding occurs, lower permeability limits the diffuse flow of gas upward through the ignimbrite from the region of boiling and pore pressurization at the base, and enhanced devitrification in the basal parts of the ignimbrite may occur where pore vapors circulate in abundance. Immediately above the welded zone, a devitrified horizon may develop where the upper boiling/condensation zone and perched meteoric infiltration results in enhanced saturations.
From Boxed Lunch to Learning Boxes: An Interdisciplinary Approach

The inspiration for this article was not conceived over lunch, but more specifically over the box in which the lunches were packaged. Five colleagues brainstormed ideas for teaching a unit on trees for the third grade that would fit in our boxes. The disciplines involved were art, children's literature, science, social studies, and technology. Each person decorated the lunch box for their appropriate discipline and placed instructional items inside. Technology was infused throughout the unit.
Separation and characterization of HeLa alkaline pyrophosphatase isoenzymes

Abstract Three electrophoretic forms (isoenzymes) of alkaline pyrophosphatase from a human cell line HeLa Ch have been separated by preparative starch-gel electrophoresis followed by electrodialysis. One isoenzyme has an inorganic pyrophosphatase pH optimum of 8.8, whereas the other two isoenzymes have pyrophosphatase pH optima between 9.5 and 10.0. Both of the latter isoenzymes have inorganic pyrophosphatase activities which are inhibited by magnesium, whereas the pyrophosphatase activity of the protein with a pH optimum of 8.8 is not affected by this cation. All three proteins also possess magnesium-stimulated phosphomonoesterase activity with pH optima near 10. A purified preparation of these enzymes was used to study the substrate specificity as a pyrophosphatase. ADP and ATP, CDP and CTP, GDP and GTP, UDP, UTP, and ITP also functioned as substrates, in addition to PP i , whereas the biterminally substituted pyrophosphate NAD + did not serve as a substrate. Although both d - and l - cysteine inhibited the inorganic pyrophosphatase and phosphomonoesterase activities of these isoenzymes to the same extent, l -phenylalanine and l -tryptophan inhibited the pyrophosphatase activity less effectively than the phosphatase activity, suggesting interaction with an allosteric site. The molecular weights of these proteins are 100,000 as estimated by sucrose-density centrifugation and 150,000 as estimated by Sephadex G-200 chromatography.
Expression of a New Cellular Protein by Monocytoid B-Lymphocytes Differentiated from the Acute Lymphoblastic Leukemia Cell Line (REH).

In an attempt to identify differentiation-related changes in cellular proteins, the common acute lymphoblastic leukemia (ALL) cell line, REH, was studied. REH cells were cultured in either the absence or presence of 12-0-tetradecanoylphorbol-13-acetate (TPA). Changes in surface phenotype were analyzed using monoclonal antibodies and flow cytometry. Cellular proteins were analyzed with two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) of [3H]leucine and [32P]orthophosphate labeled cells. Immunophenotype and 2D-PAGE studies were replicated three times on untreated (control) and TPA-treated cells on day 5. Immunophenotypic analysis showed that TPA induced further differentiation of REH cells along the B-cell lineage as indicated by significant decrease in the expression of CD10, induction of CD11c and increase in the expression of CD22. 2D-PAGE of [3H]leucine but not the [32P]orthophosphate showed that TPA induced the expression of a unique protein. The apparent relative molecular mass (Mr) of the...
Membrane association of NAD pyrophosphatase inSalmonella typhimurium

Salmonella typhimurium was fractionated into cytoplasmic, periplasmic, and membrane fractions to determine the cellular location of nicotinamide adenine dinucleotide pyrophosphatase. The results indicate that this enzyme is associated almost exclusively with the inner membrane. Studies utilizing porin mutants indicate that NAD probably transverses the outer membrane via pores and is degraded to NMN at the inner membrane by NAD pyrophosphatase. Based upon the lack of significant NAD pyrophosphatase activity in cytoplasmic fractions, we theorize that most if not all intracellular turnover of NAD is probably the result of DNA ligase activity.
Correlation measurements of laser beam fluctuations near threshold

Abstract The intensity fluctuations of a He:Ne laser have been studied near threshold by photoelectric correlation techniques. The intensity correlation functions are found to be nearly exponential, and their peak values and decay constants are in good agreement with laser theories based on solutions of the Fokker-Planck equation.
Ankle-dorsiflexion range of motion and landing biomechanics.

Abstract Context: A smaller amount of ankle-dorsiflexion displacement during landing is associated with less knee-flexion displacement and greater ground reaction forces, and greater ground reactio...
T Cell Populations and Cytokine Expression in Milk Derived from Normal and Bacteria-Infected Bovine Mammary Glands

Abstract This study investigated the effect of naturally acquired bacterial infection of the bovine mammary gland on subpopulations of T lymphocytes and cytokine expression in milk. Twenty-nine lactating cows with mastitis were compared to 12 normal animals. CD4 + lymphocytes represented a significantly greater percentage of the milk-derived lymphocytes in infected mammary glands compared to normal controls. Cytokine mRNA expression by cells derived from milk was investigated using reverse transcriptase–polymerase chain reaction (RT–PCR). No IL-2 or IL-4 mRNA was detected in any samples, while IFN-γ mRNA was detected in all milk samples. IL-10 mRNA was detected in cells from the milk of 2 mastitic cows and 1 normal cow, and IL-12 mRNA was detected in 2 cows with mastitis. While TNF-α mRNA was not detected in this study, IL-6 mRNA was identified in cells from the milk of all animals, with levels being greater in mastitic animals.
The electrocardiographic diagnosis of left ventricular hypertrophy in apparently normal children

Serial electrocardiographic, vectorcardiographic, and clinical features in 18 children with markedly increased precordial electrocardiographic voltages suggestive of left ventricular hypertrophy are presented. Patients were followed for an average of 31/2 years in order to determine the long-term significance of this finding. Follow-up electrocardiograms were normal in about 30 per cent; precordial voltages were unchanged or increased in about 70 per cent. No child had signs or symptoms of cardiovascular disease, but three subjects (15 per cent) had persistently increased precordial voltages and increased cardiothoracic ratio on chest radiographs. It is suggested that children with increased precordial voltages be followed clinically until the electrocardiogram becomes normal or the diagnosis is otherwise clarified.
Social economics of childhood glucocorticoid stress response and health

This study examines socioeconomic conditions, psychosocial stress, and health among 264 infants, children, adolescents, and young adults aged 2 months to 18 years residing in a rural Caribbean village. Fieldwork was conducted over a 9 year period (1988-1996). Research methods and techniques include salivary cortisol radioimmunoassay (N 5 22,438), system- atic behavioral observations, psychological questionnaires, health evalua- tions, medical records, informal interviews, and participant observation. Analyses of data indicate complex relations among socioeconomic condi- tions, stress, and health. Household income, land ownership, parental education, and other socioeconomic measures are weakly associated with child illness. There is no evidence that apparent material benefits of high socioeconomic status—such as improved housing, diet, work loads, and access to private healthcare—have important direct effects on child health in this population. However, social relationships, especially family environment, may have important effects on childhood psychosocial stress and illness. Abnormal glucocorticoid response profiles, diminished immunity, and fre- quent illness are associated with unstable mating relationships of parents/ caretakers and household composition. We suggest that family relationships and concomitant stress and immunosuppression are important intermediary links between socioeconomic conditions and child health. Am J Phys Anthro-
Optics in Germany

This article presents a short survey of the people and organizations active in optics research in Germany.
Fault Tolerant Operations in Adjustable-Speed Drives and Soft Starters for Induction Motors

Fault tolerant operations of soft starters and adjustable-speed drives (ASDs) when experiencing power switch open-circuit or short-circuit faults are presented in this paper. The present low-cost fault mitigation solutions can be retrofitted into the existing off-the-shelf soft starters and ASDs with only minimum hardware modifications. The fault tolerant soft starters are capable of operating in a two-phase mode under the condition of thyristor/SCR open-circuit or short-circuit switch-fault in any one of the phases using a novel resilient closed-loop control scheme. The performance resulted from the present soft starter fault tolerant control has demonstrated reduced starting motor torque transient and inrush current magnitude. As for the ASDs, a low-cost fault mitigation strategy for low-speed applications such as "self-healing/limp-home" needs for vehicles and propulsion systems, with capabilities for mitigating transistor open-circuit and short-circuit switch-faults was developed. The present fault tolerant drive topology requires only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, with only the addition of electronic components such as triacs and fast-acting fuses. In addition, the present approach offers the potential of mitigating not only transistor switch-faults but also drive related faults such as rectifier diode short-circuit fault or dc link capacitor fault. Given in this paper is a complete set of simulation results that demonstrate the soundness and effectiveness of the present fault tolerant approaches.
Should the Interquartile Range Divided by the Standard Deviation be Used to Assess Normality

We discourage the use of a diagnostic for normality: the interquartile range divided by the standard deviation. This statistic has been suggested in several introductory statistics books as a method to assess normality. Through simulation, we explore the rate at which this statistic converges to its asymptotic normal distribution, and the actual size of tests based on the asymptotic distribution at several sample sizes. We show that there are nonnormal distributions from which this method cannot detect a difference. Additionally, we show the power of this test for normality is quite poor when compared with the Shapiro–Wilk test.
Decentralized and fair rate control in a multisector CDMA system

As the demand for wireless broadband data services grows, it becomes increasingly important to address the issue of optimal resource allocation. Specifically, such allocation should address not only quality of service (QOS) requirements, but continually changing resource demands. This paper examines such optimal resource allocation through nonuniform rate assignment in a CDMA system, using a proportional fair scheme. We also examine distributed algorithms for such a rate assignment, and their performance in dynamic systems.
Mediating off-site electronic reference services: human-computer interactions between librarians and Web mining technology

The Internet enables global dissemination and retrieval of information at any time; as a result, it has a tremendous impact on how libraries provide reference services to this new Web based clientele. One impact is the increase in off-site library users who make in-person reference interviews impossible. To serve this new clientele, academic libraries are setting up electronic reference services to meet off-site information needs. This new approach requires effective human-machine connections to provide smooth reference transactions since librarian-patron contact happens solely through computers. The most challenging aspect of providing electronic reference services to off-site users is deciding when patrons need help. Pertinent information technology is needed to track Web traffic patterns and user behavior (e.g. Web mining), addressing immediately the difficulties encountered by end users. The paper focuses on human-computer connections relating to reference librarians' application of Web mining technology to transfer their experiences and skills from the reference desk to the Web environment. It examines Web mining techniques and their potential to assist different library functions. A scenario is used to conceptualize a model that can effectively apply Web mining technology to perform various functions of electronic reference services. It also proposes a methodology that librarians can adapt in offering mediation during the search at patrons' discretion. The main goal is to provide more seamless electronic reference transactions. Discussion of library professionals' roles in human-computer interactions in the electronic world is presented.
PARAMETER SENSITIVITY OF A MODEL OF VIRAL EPIDEMICS SIMULATED WITH MONTE CARLO TECHNIQUES. III. OPTIMIZATION STRATEGIES

The output of the sensitivity analysis system, SENSEN, described in the preceding two papers is applied to an optimization study for the VESPERS model of the spread of infection with influenza virus in a community. We know of no similar studies. In this application, constrained, non-linear optimization routines in IMSL are used. The optimization study attempts to answer whether behavioural modification (modeled as discrete interventions) is necessary to represent simultaneously the age-specific attack rates and the epidemic curve. The results presented here indicate that such model interventions are necessary.
Double step branching CORDIC: a new algorithm for fast sine and cosine generation

Duprat and Muller (1993) introduced the ingenious "Branching CORDIC" algorithm. It enables a fast implementation of CORDIC algorithm using signed digits and requires a constant normalization factor. The speedup is achieved by performing two basic CORDIC rotations in parallel in two separate modules. In their method, both modules perform identical computation except when the algorithm is in a "branching" [1]. We have improved the algorithm and show that it is possible to perform two circular mode rotations in a single step, with little additional hardware. In our method, both modules perform distinct computations at each step which leads to a better utilization of the hardware and the possibility of further speedup over the original method. Architectures for VLSI implementation of our algorithm are discussed.
Estrogen enhances endometrial estrogen receptor gene expression by a posttranscriptional mechanism in the ovariectomized ewe.

Prior influence of estrogen is required for many physiological effects of steroid hormones. This study addresses positive autoregulation of estrogen receptor gene expression in endometrium. Groups of ovariectomized ewes (n = 6) were treated with a single i.m. injection of 50 micrograms 17 beta-estradiol for 6, 12, 24, or 48 h or of vehicle for 24 h (control) prior to collection of endometrium. Three ewes received a regimen of estradiol-progesterone-estradiol (EPE) designed to mimic the estrous cycle. Northern analysis of endometrial RNA using an ovine estrogen receptor complementary RNA probe indicated that estradiol increased (p 0.25). These results suggest that a physiological dose of estradiol, similar to the preovulatory surge of estrogen, up-regulates endometrial estrogen receptor gene expression by a posttranscriptional mechanism.
Reintegrative Shaming and Predatory Delinquency

This study represents an attempt to test Braithwaite’s theory of reintegrative shaming with an operationalization scheme of two variables—disapproval of delinquent behavior (shaming) and forgiveness of the transgressor (reintegration) by parents and peers. The study combines measures of delinquency disapproval and forgiveness of the transgressor by parents and peers to capture the concept of reintegrative shaming. Using data collected from the first two waves of the National Youth Survey, the study finds no effect of either parental reintegrative shaming or peer reintegrative shaming on predatory delinquency in either wave when the effects of other important variables are held constant. However, the data reveal that parental forgiveness and peer shaming alone have significant and negative effects on the likelihood of being involved in predatory offenses in both waves. In contrast, peer forgiveness shows a significant and positive effect on predatory offense involvement in the first wave. The findings prov...
Ethanol effects proinflammatory state of neutrophils in shock.

Introduction Ethanol (EtOH) intoxication plays an important role in the etiology of traumatic events and has often been described as having immunosuppressive effects. EtOH has been shown to affect intestinal barrier function in prior studies. The ability of gut derived factors on neutrophil function in this setting is unknown. This study looks at the role of ethanol in modulating proinflammatory states in the neutrophil in vitro . Methods Confluent Caco2 monolayers were exposed to 0.1% EtOH and/or Escherichia coli C-25 (EC) under normoxia (21% O 2 ) or hypoxia (5% O 2 ) followed by normoxic conditions (H/R). Neutrophils were then incubated with the supernatants from the treated cells. Chemotaxis, elastase and superoxide anion release, and CD11b measurements were undertaken in these neutrophils and compared with controls. Results In the presence of EtOH, Caco2 cells undergoing H/R and bacterial challenge demonstrated a proinflammatory effect on neutrophils. The production of both elastase and superoxide anion were significantly increased from controls. Additionally, the presence of EtOH in Caco2 cells undergoing H/R with/without EC showed a statistically significant increase in CD11b expression and chemotaxis, when compared with controls. Conclusions EtOH has a proinflammatory role in the activation of neutrophils at the intestinal epithelial cell barrier in shock states. EtOH may play an important role in worsening septic complication in severely traumatized patients via dysregulation of neutrophils.
A parallel QR algorithm for the symmetrical tridiagonal eigenvalue problem

A parallel/pipelined algorithm and its architecture are proposed to solve the symmetric eigenvalue problem. This algorithm is based on Given's rotations, and it is associated with the initial reduction of the dense matrix to a tridiagonal one using Householder's transformations. The performance of this algorithm is described and compared to the performance of the sequential one. It can be shown that the cost of the eigendecomposition falls from O(m*n) to O(m+n), where m and n denote the matrix order and the number of iterations, respectively. This algorithm is mapped on m processors to compute the eigenvalues and eigenvectors simultaneously. >
Black guitar-players and early African-Iberian music in Portugal and Brazil

Some of the most interesting and puzzling early guitar sources are held in Portugal, at Lisbon's Calouste Gulbenkian Foundation and at Coimbra University Library. Notated in tablature, they display a large number of pieces of supposed African origin, along with many Iberian dances and instrumental items. While the African influence is suggested by the titles, literary sources, historical context and musical features, dances such as the arromba, caozinho, cubanco, gandu, sarambeque, cumbe and paracumbe also reveal a strong connection with Iberian forms from the period, such as the canario, villano and jacaras. Its ultimate place of origin—Africa, Iberia or America—does not seem as relevant as the interaction process itself, with all the economic, social, racial and political implications: most of that repertory was shared by musicians in different places of the Iberian dominions in Europe, Africa and the Americas, be they white or black, slaves or free artists. The article contextualizes that repertory historically, relying mostly on the works by Brazilian poet Gregorio de Mattos (1636–96), a source of information on the music heard in the streets, homes, convents and brothels of 17th-century Brazil. Many of his descriptions and opinions deal with the music of slaves, free blacks and mulattos; they include many of the titles found in Portuguese guitar tablatures. The analysis of this musical material raises important questions that are addressed in the article: was this music created by black guitar players who assimilated Iberian materials and playing techniques? Or was it composed by white Iberian musicians, maybe as exotic depictions, or caricatures? What is African and what is Iberian in such music, and on what terms did such interaction take place? The article finishes with historical data on Brazilian mulatto musicians—guitar players, singers and poets—who lived in Lisbon and enjoyed some success during the second half of the 18th century.
Frequency of Encounter with Risk and the Tradeoff between Pursuit and Antipredator Behaviors in Crayfish: A Test of the Risk Allocation Hypothesis

Prey animals encountering multiple stimuli must often make behavioral tradeoffs. Many environmental cues may influence the tradeoff observed, but recent theoretical work suggests that temporal variation in risk should influence how prey animals behave during any given period of risk. As time spent under risk of predation increases, prey animals will increase their allocation of foraging during periods of risk. This model is known as the risk allocation hypothesis (RAH) (Lima & Bednekoff 1999). We tested the RAH using the crayfish Orconectes virilis. We selected two frequency regimes (exposure to risk every 6 or 12 h) and three cues suggestive of increasing risk (water, snapping turtle cue, and conspecific alarm cue). Test animals were exposed to one of the six frequency x risk combinations for 24 h, followed immediately by the simultaneous introduction of a food and a risk cue. Three behaviors (burrow use, non-ambulatory motion, and locomotion) were then recorded for 5 min. Responses were significantly influenced by the interaction of risk and frequency. Further analysis indicated that responses were not consistently influenced by frequency alone. While our results do not support the predictions of the RAH for our frequency regimes, qualitative comparison with an earlier, similar study (Hazlett 1999) suggests that risk allocation is occurring in this system. We recommend that frequency of encounter with risk be considered in future studies. Ignoring temporal variation may lead to over- or underestimation of the subject's natural responses.
Normal and abnormal pulmonary arteriovenous shunting: occurrence and mechanisms

Severe cyanosis due to pulmonary arteriovenous fistulas occurs often after a bidirectional superior cavopulmonary anastomosis (Glenn operation) and also in some congenital anomalies in which hepatic venous blood bypasses the lungs in the first passage. Relocation of hepatic flow into the lungs usually causes these fistulas to disappear. Similar pulmonary arteriovenous fistulas are observed in hereditary haemorrhagic telangiectasia, and in liver disease (hepatopulmonary syndrome). There is no convincing identification yet of a responsible hepatic factor that produces these lesions. Candidates for such a factor are reviewed, and the possibility of angiotensin or bradykinin contributing to the fistulas is discussed.
Mass psychogenic illness in organizations: An overview

Published and unpublished reports of mass psychogenic illness, defined as the collective occurrence of physical symptoms and related beliefs among two or more persons in the absence of an identifiable pathogen, are reviewed with particular emphasis on organizationa l occurrences. A number of factors (e.g. boredom, sex-role identification, interpersonal conflict, physical stress) are identified as potential precipitating conditions, and the contagion of symptoms is discussed in terms of the convergence-contagion dichotomy in collective behaviour suggested by Milgram & Toch (1969). There is some evidence to indicate that the actual occurrence of contagious psychogenic illness in organizations is more frequent than the available literature would suggest (CoUigan & Smith, 1978). In the past, the underreporting of this phenomenon may be attributed to the fact that outbreaks of such illness are typically investigated by teams of industrial hygienists and medical professionals whose primary concern is the possibility of toxic exposure. The results of these investigations are then summarized in internal staff reports for limited distribution. Should environmental tests and medical evaluations prove inconclusive, a suggestion may be made that psychogenic factors played a contributory, if not primary, role in the aetiology of the illness. This conclusion is based more on the absence of a clearly identified pathogen than the presence of well-defined psychosocial precipitating factors. Unfortunately, merely labelling the phenomenon as 'psychosomati c' or 'anxiety induced' does little in promoting an understanding of the dynamics of the illness. The present paper draws upon published and unpublished reports about contagious psychogenic illness in organizations . Sixteen studies are analysed in detail, of which seven involve work environments and nine involve school settings. These organizational studies may be viewed as complementary to investigations of such illness outbreaks in larger communities (e.g. Fallaize, 1923; Halliday, 1948; Yap, 1952) which are beyond the scope of the present review. Table 1 presents summary descriptions of these investigations. The original reports vary considerably in terms of thoroughness and the nature of the data presented. In fact, the absence of a consistent and systematic data base has been one of the major impediments to a current understanding of this phenomenon. Nevertheless, it is hoped that sufficient information may be derived from these admittedly sketchy reports to provide direction for future research in this important area.
Core–mantle boundary topography as a possible constraint on lower mantle chemistry and dynamics

article i nfo The origin of large low shear-wave velocity provinces (LLSVPs) in the lowermost mantle beneath the central Pacific and Africa is not well constrained. We explore numerical convection calculations for two proposed hypotheses for these anomalies, namely, thermal upwellings (e.g., plume clusters) and large intrinsically dense piles of mantle material (e.g., thermochemical piles), each of which uniquely affects the topography on Earth's core-mantle boundary (CMB). The thermochemical pile models predict a relatively flat but elevated CMB beneath piles (presumed LLSVPs), with strong upwarping along LLSVP margins. The plume cluster models predict CMB upwarping beneath upwellings that are less geographically organized. Both models display CMB depressions beneath subduction related downwelling. While each of the two models produces a unique, characteristic style of CMB topography, we find that seismic models will require shorter length scales than are currently being employed in order to distinguish between the end-member dynamic models presented here.
The routine use of the Edmonton Classification System for Cancer Pain in an outpatient supportive care center.

Objective: There is no standardized and universally accepted pain classification system for the assessment and management of cancer pain in both clinical practice and research studies. The Edmonton Classification System for Cancer Pain (ECS–CP) is an assessment tool that has demonstrated value in assessing pain characteristics and response. The purpose of our study was to determine the relationship between negative ECS–CP features and some pain-related variables like pain intensity and opioid use. We also explored whether the number of negative ECS–CP features was associated with higher pain intensity. Method: The electronic charts of 100 patients at an outpatient supportive care clinic in a comprehensive cancer center were reviewed for variables like patient characteristics, initial ECS–CP assessment, morphine equivalent daily dose (MEDD), opioid rotation, Edmonton Symptom Assessment Score (ESAS), and use of adjuvant analgesics. Results: Some 91 of the 100 charts were eligible for analysis. The most common primary cancer type was gastrointestinal (22.1%). The median pain intensity was 6, and the median MEDD was 45 mg. Neuropathic pain was associated with higher median pain intensity (7 vs. 5, p = 0.007) and median MEDD requirement (83 vs. 30, p = 0.013). Psychological distress was associated with higher median pain intensity (7 vs. 5, p = 0.042). Incident pain was also associated with a trend toward higher pain intensity (6 vs. 5, p = 0.06). A higher number of negative ECS–CP features was associated with higher pain intensity (p = 0.01). Significance of Results: The ECS–CP was successfully completed in the majority of patients, demonstrating its utility in routine clinical practice. Neuropathic pain and psychological distress were associated with higher pain intensity. Also, neuropathic pain was associated with a higher MEDD. A higher sum of negative ECS–CP features was associated with higher pain intensity. Further studies will be needed to verify and explore these observations.
Pole cells of Drosophila melanogaster in culture. Normal metabolism, ultrastructure, and functional capabilities.

Abstract The metabolism, ultrastructure, and function of mass-isolated pole cells were examined during short-term culture in vitro. In addition to demonstrating that these cells functioned normally in culture, a number of new features of embryonic pole cells were discovered. Cell populations isolated from Renografin density gradients were incubated in medium containing tritiated valine, uridine, or thymidine. Although pole cells incorporated similar amounts of valine into protein as other embryonic cells throughout the first 6 hr in culture, they began to synthesize RNA only after 2 hr in culture. Approximately 30% of the pole cells synthesized DNA in vitro and this synthetic activity occurred largely during the first hour of culture. An ultrastructural analysis of colcemid-treated cells showed that 10% of the pole cells divide shortly after placement in culture. During pole cell culture in vitro, polar granules and nuclear bodies fragment and disperse so that they are eventually not detected in these cells. These changes also occur during pole cell development in vivo. Finally, we have obtained 25 to 33% germ line mosaicism among the fertile adults which were derived from embryos receiving transplantation of isolated pole cells before and after culture in vitro. These results demonstrate that these cells are able to follow their normal developmental program in vitro and are able to give rise to functional germ cells in vivo.
Fetal development in the normal thick-tailed bushbaby (Galago crassicaudatus panganiensis).

Fetal development was examined at days 60, 75, 90, 105, 120, or 135 of gestation in 19 thick-tailed bushbaby fetuses (Galago crassicaudatus panganiensis) from 17 normal, timed pregnancies. With the exception of day 135, all fetuses were collected by hysterotomy (gestation = 133 ± 2 days). Various weights and measurements were taken. Although fetal sizes varied widely, crown-rump, crown-heel, upper and lower arm and leg lengths, hand and foot lenghts, and fetal organ weights correlated well with fetal age. Key changes in gross brain morphology and skeletal ossification of cranium, pelvis, tarsals, carpals, and epiphyses were noted. Sternabrae ossification proved highly variable, while ossification in the otic capsule and associated ear structures correlated well with age. These data provide a normal base for studies using fetal developmental parameters whether the purpose is to determine gestational age or to design future studies.
Effects of tree leaf litter, deer fecal pellets, and soil properties on growth of an introduced earthworm (Lumbricus terrestris): Implications for invasion dynamics

Abstract Invasive earthworm communities are expanding into previously earthworm-free forests of North America, producing profound ecosystem changes. Lumbricus terrestris is an invasive anecic earthworm that consumes a large portion of the detritus on the soil surface, eliminating forest floor organic horizons and reducing soil organic matter. Two mesocosm experiments were used to examine the individual and combined effects of litter and soil type on the growth of L. terrestris. The litter type experiment tested nine different food source treatments (7 tree leaf litters, deer fecal pellets, and a control), while the soil × litter type experiment used five different soil treatments (4 soil types and one soil type with A horizon material removed) in combination with four different food source treatments. We found that leaf litter type (p = 0.001) and soil type (p = 0.018) significantly affected earthworm growth rates, with growth rates on deer pellets similar to many high quality deciduous leaf litters. Of soil variables, exchangeable Ca (r 2 = 0.99), sum base cations (r 2 = 0.98), % organic matter (r 2 = 0.93), %N (r 2 = 0.89), %C (r 2 = 0.87), and exchangeable Mg (r 2 = 0.85) were all significant predictors of earthworm growth. Litter disappearance of all litter types was linearly related to growth, suggesting similar growth efficiency on different litter types. However, chemical properties, specifically foliar C:N and a linear combination of a suite of other chemical properties predicted growth, suggesting that consumption or gut passage rates were regulated by litter quality. This information about soil and litter characteristics that regulate L. terrestris growth should improve models of their distribution, spread and abundance.
Bandwidth enhancement in multimode fibers

We report on a substantial improvement in the bandwidth of graded index multimode fibers caused by a controlled intentional mode coupling. Scattering from micron size core inclusions induce the mode coupling with minimum power loss.
Environmental Impacts of Packaging in the U.S. and Mexico

The rise in environmental consciousness in recent decades has included a focus on household waste. It is not the most urgent of the problems we face, but it may be the most immediately accessible. Global climate change, the destruction of the rain forests, and disasters such as Chernobyl and Bhopal are far away and hard for an individual to influence; but garbage disposal happens again and again, right at home under our personal control. Those who seek to act on their environmental concerns, therefore, often find it easiest to begin with the problems of solid waste. When a 1990 Gallup poll asked people in the United States what they had done in connection with environmental problems, 80% to 85% answered that they or their households had participated in various aspects of recycling; no other significant steps had been taken by a majority of respondents (Dunlap and Scarce, 1991, tables 44-46).
On “Dyar'S Rule” and Its Application to Sawfly Larvae.

Forty years ago Dyar (1890) sought to establish a criterion by which it would be possible to determine, by simple mathematics, the correctness or incorrectness of the number of instars observed. This was based upon the apparent close agreement between calculated and actual widths of the heads of all larval instars of 28 species of caterpillars, which had from four to ten stadia. In most cases, the calculated and observed widths were either identical or within 0.1 mm., though, apparently, a discrepancy of 0.2 mm. was not considered significant. In six cases of greater deviation in various instars among these species, the explanation offered was “abnormal development”—either dwarfing, because the larva was “unhealthy” and failed to cast its skin, etc., or unusual growth. In five other cases, probable incorrect measurements were admitted. From these data, Dyar found that the size of the larval head is (relatively) static during a stadium and that “… the widths of the head of a larva in its successive stages follow a regular geometrical progression …” (It was suggested that the width of the larval head is the most convenient measurement to take.)
Action and Uncertainty in Neonatal Intensive Care.

The target article by Blumenthal-Barby evaluates biases and heuristics that may interfere with the ability of medical decision makers to act in a truly autonomous manner (Blumenthal-Barby 2016). In...