cssi/SciSciGPT-SciSciNet huggingface dataset:
Metabolic role of vitamin B12.

Publisher Summary This chapter discusses the cleavage and synthesis of the carbon-to-cobalt bond and enzyme-catalyzed reactions requiring 5'-deoxyadenosyl cobamides. The enzymatic reactions requiring vitamin B 12 derivatives can be divided into two major groups: (1) those that utilize 5′-deoxyadenosyl-B 12 and involve a hydrogen transfer and (2) those that involve a methyl group transfer, probably via a methyl-B 12 enzyme. The reactions requiring 5′-deoxyadenosyl-B 12 are illustrated and described in the chapter. The chapter describes the role of vitamin B 12 in animal metabolism. Studies with pernicious anemia patients have suggested that vitamin B 12 is required primarily for DNA synthesis, which is essential for the normal development of the mature red blood cell in the bone marrow. In addition, it is well established that there is a nutritional interrelationship among folic acid, vitamin B 12 , and one-carbon metabolism. A summary of various tetrahydrofolic acid derivatives that depicts their role in one-carbon metabolism is illustrated in the chapter. It is observed that tetrahydrofolate is directly involved in the synthesis of purines, thymidylate, and methionine.
Safety analysis of requirements for a product family

A safety analysis was performed on the software requirements for a family of flight instrumentation displays of commercial aircraft. First, an existing safety checklist was extended to apply to four-variable models and used to analyze the requirements models for representative members of the product family. The results were evaluated against an initial specification of the product family's required commonalities and variabilities. The safety checklist was found to be effective at analyzing the completeness of the product family requirements and at identifying additional variabilities and commonalities. Secondly, a forward and backward search for hazards was performed on representative members of the product family. Additional safety requirements for enhanced fault tolerance were derived from these searches. The safety analysis techniques used here appear to have applicability for enhancing the completeness and robustness of a product family's safety related software requirements.
Oxidation of Nanomolar Levels of Fe(II) with Oxygen in Natural Waters

The oxidation of Fe(II) by molecular oxygen at nanomolar levels has been studied using a UV−Vis spectrophotometric system equipped with a long liquid waveguide capillary flow cell. The effect of pH (6.5−8.2), NaHCO3 (0.1−9 mM), temperature (3−35 °C), and salinity (0−36) on the oxidation of Fe(II) are presented. The first-order oxidation rates at nanomolar Fe(II) are higher than the values at micromolar levels at a pH below 7.5 and lower than the values at a higher pH. A kinetic model has been developed to consider the mechanism of the Fe(II) oxidation and the speciation of Fe(II) in seawater, the interactions between the major ions, and the oxidation rates of the different Fe(II) species. The concentration of Fe(II) is largely controlled by oxidation with O2 and O2•- but is also affected by hydrogen peroxide that may be both initially present and formed from the oxidation of Fe(II) by superoxide. The model has been applied to describe the effect of pH, concentration of NaHCO3, temperature, and salinity on...
Porphyrins: XII. Luminescence of copper complexes at liquid nitrogen temperature

Abstract Luminescence spectra, excitation spectra, lifetimes, and quantum yields at liquid nitrogen temperature in various solvents are reported for several copper porphyrins in an attempt to understand the nature of the luminescent state. From excitation spectra a natural radiative lifetime of the luminescent “tripdoublet” state is estimated at ∼70 μsec for Cu octalkylporphin, with observed lifetimes from 60–80 μsec, and yields ∼0.6. Both CuTPP and CuP show nonexponential decay curves. The decay curve for CuTPP can be fitted with three lifetimes (∼600 μsec, ∼150 μsec, ∼25 μsec) while CuP can be fitted with two time (∼750 μsec, ∼150 μsec). The CuEtio luminescence is shown to persist weakly at room temperature. Some effects of solvent on the spectra are discussed: In particular the complexing effect of organic bases and the band sharpening in certain n-paraffins.
Production of green bioplastics from agri-food chain residues and co-products

Abstract: The environmental benefits are elucidated of polyhydroxyalkanoates (PHAs), natural thermoplastics synthesised by microbial species on renewable carbon sources, which may substantially reduce plastic pollution, greenhouse gas emissions and fossil energy consumption by replacing their petrochemical counterparts. Agri-food chain co-products are potential feedstocks for PHA bioplastics with technology innovations in pretreatment, microbial fermentation, and polymer recovery and purification. Pre-treatment is to convert special co-products into fermentative substrates and precursors for microbial biosynthesis of polyesters with desired molecular size, chemical composition and material properties. High volumetric productivity is a technical and economical indicator of PHA fermentation technology and can be achieved by using high cell density culture on highly concentrated feedstocks. Technical limitations may result in low to moderate productivities in large bioreactors with feedstocks of low carbon content. PHA recovery and purification is an essential and costly step in the process, which has moderated progress in technical innovation compared with PHA biosynthesis and material science. Problems are analyzed for potential breakthrough in polymer recovery and purification. In the near future, microbial production of PHA bioplastics could be integrated into advanced biorefineries to make fuels, chemicals and materials from renewable biomass including agri-food chain co-products in a cost-effective way.
Contemporary Issues in California Archaeology

Contemporary Issues in California Archaeology Terry L. Jones and Jennifer E. Perry (editors) 2012. Left Coast Press, Inc., Walnut Creek, California. 396 pp. $39.95 (paper). ISBN 978-1-61132-092-3.F...
Interactive Modeling, Simulation and Control of Large-Scale Crowds and Traffic

We survey some of our recent work on interactive modeling, simulation, and control of large-scale crowds and traffic for urban scenes. The driving applications of our work include real-time simulation for computer games, virtual environments, and avatar-based online 3D social networks. We also present some preliminary results and proof-of-concept demonstrations.
Detection of a protein of avian leukoviruses in uninfected chick cells by radioimmunoassay.

A radioimmunoassay (RIA) was used to measure the quantity of protein P27 (mol wt 27,000; group specific-1 STAgs-1!) of avian leukoviruses in different types of chicken embryos and tissues of adult chickens. The RIA used was 200- to 300-fold more sensitive than the complement fixation test and was able to detect as little as 0.3 ng of P27. Among six embryos tested, which are negative for gs antigen by the complement fixation test, P27 was undetectable in three embryos, but another three contained about 5 ng of P27 per mg of cell protein by RIA. The amount of P27 in gs antigen-positive cells ranged from 22 to 57 ng per mg of cell protein. P27 was found in liver, lung, ovary, feather pulp, and spleen from adult gs antigen-positive chickens. This protein was undetectable in various tissues from gs antigen-negntive chickens. (auth) Shallow range distributions are altered significantly by diffusion and surface erosion. It is shown the simultaneous processes of implantation, diffusion, and surface erosion can be described by a second-order differential equation which is mathematically tractable and yields general results in terms of analytical functions. The resulting depth distributions depend on one parameter only which is a combination ofmore » the mean particle range, the diffusion coefficient, and the velocity of surface erosion (e.g., sputtering). The theory is applied to practical cases, e.g., implantation of plasma particles in the wall of fusion reactors, or solar wind ions in the surface of meteorite materials. (auth)« less
Wages through the Ages: The Influence of Technology on the Standard of Living

This paper is a review of 850 years of the history of worker salary, cost of living, and productivity. ``Nicholson's Journal'' of 1798 provides data on English farming back to 1050 A.D. by reviewing old chronicles and the household records of kings. To relate the past to the present, modern history is extended using American farming data compiled by the U.S. Department of Commerce since 1804. Farming is one of the few occupations with a long, continuous history. The industrial revolution and automation have had their influence on farm employment and productivity. From this review of data, relative productive wages (defined as salary divided by cost of living divided by productivity) are quantitatively found to have remained constant (within a factor of ±2) for 850 years?in spite of historical events such as the Black Plague, the Industrial Revolution, and the Great Depression. Finally, this principle of relative productive wages is used to speculate about the short- and long-term influence of automation on our future economic standard of living.
Development of an instrument to understand the child protective services decision-making process, with a focus on placement decisions

When children come to the attention of the child welfare system, they become involved in a decision-making process in which decisions are made that have a significant effect on their future and well-being. The decision to remove children from their families is particularly complex; yet surprisingly little is understood about this decision-making process. This paper presents the results of a study to develop an instrument to explore, at the caseworker level, the context of the removal decision, with the objective of understanding the influence of the individual and organizational factors on this decision, drawing from the Decision Making Ecology as the underlying rationale for obtaining the measures. The instrument was based on the development of decision-making scales used in prior decision-making studies and administered to child protection caseworkers in several states. Analyses included reliability analyses, principal components analyses, and inter-correlations among the resulting scales. For one scale regarding removal decisions, a principal components analysis resulted in the extraction of two components, jointly identified as caseworkers' decision-making orientation, described as (1) an internal reference to decision-making and (2) an external reference to decision-making. Reliability analyses demonstrated acceptable to high internal consistency for 9 of the 11 scales. Full details of the reliability analyses, principal components analyses, and inter-correlations among the seven scales are discussed, along with implications for practice and the utility of this instrument to support the understanding of decision-making in child welfare.
Optimal wage re-negotiation in a closed and open economy

Abstract This paper investigates an economy in which there are short-term wage contracts that are re-negotiated under certain conditions. The paper determines the optimal frequency of wage re-negotiation and shows that it depends positively on measures of aggregate variability and Phillips curve slope. The role of optimal wage re-negotiation is to mitigate the output effects of various shocks. In the context of an open economy, it is shown that the desirable exchange rate regime in an economy with optimal wage re-negotiation depends on the stochastic structure of the economy.
Shifts in Bovine CD4+ Subpopulations Increase T-helper-2 Compared with T-helper-1 Effector Cells During the Postpartum Period

Abstract This study determined the cytokine profile of CD4 + T-helper cells to elucidate the specific CD4 + T-helper phenotype during the postpartum period. Peripheral blood mononuclear cells were isolated from cows during periods of increased susceptibility (3 d postpartum, n=7) and decreased susceptibility (mid- to late lactation, n=6) to mastitis. Isolated mononuclear cells were magnetically separated into CD4 + -enriched or CD4 + -depleted populations using specific bovine monoclonal antibodies and were confirmed to be enriched or depleted by flow cytometric analysis. T-helper- 1 and T-helper-2 subpopulations were distinguished by cytokine profiles, at both the molecular and protein level, by competitive quantitative reverse transcriptase-polymerase chain reaction and specific bioassays, respectively. The CD4 + -enriched cultures isolated postpartum had enhanced interleukin-4 and interleukin-10 mRNA transcript expression; cultures isolated during the mid- to late lactating period had enhanced interleukin-2 mRNA transcripts. Depletion of CD4 + lymphocytes decreased, and enrichment of CD4 + lymphocytes increased interferon-γ transcripts in cultures isolated from mid- to late lactation cows. Interferon-γ and interleukin-2 bioassays revealed that cytokine secretion paralleled mRNA transcript levels. These data suggest that CD4 + lymphocytes act predominantly as T-helper-2 compared with T-helper-1 within 3 d after calving. Alterations in the T-helper-1 and T-helper-2 responses, and therefore the repertoire of cytokines produced, may be an underlying reason for diminished host immune response during the postpartum period.
Shear banding and secondary flow in viscoelastic fluids between a cone and plate

Abstract When subject to flow, entangled polymer melts and wormlike micellar solutions can form adjacent regions having a shear-rate discontinuity at their interface. This phenomenon is known as shear banding, and has recently been observed using NMR microscopy [M.M. Britton, P.T. Callaghan, Phys. Rev. Lett. 78 (1997) 4930]. However, the mechanisms involved in the banding process are not well understood. One important mechanism may involve secondary flow, and in this work we study the effects of shear banding on secondary flow in viscoelastic fluids between a cone and plate. We model each band as an Oldroyd-B fluid and apply regular perturbation theory assuming that the cone angle is small. Flows with both two and three bands are considered, and we study the effects of elasticity and viscosity contrast between the bands. Elasticity contrast is found to mainly affect the strength of the secondary flow, and can even cause its direction of circulation to reverse. Viscosity contrast is found to localize the secondary flow in the less viscous band, in addition to affecting its strength. These results may help explain why the experimentally observed shear banded structure is relatively stable. They also suggest an interesting mechanism for the formation of cusps at free surfaces.
Fine structure of the mastigont system in Tritrichomonas foetus (Riedmüller).

SYNOPSIS. Tritrichomonas foetus shares many fine-structural features with the previously described genera of the subfamily Trichomonadinae. These include the arrangement and structure of the kinetosomes, of most rootlet filaments, including the sigmoid filaments of kinetosome #2, as well as those of the parabasal apparatus and of the pelta-axostyle complex. On the other hand, this species, and presumably all other Tritrichomonas augusta-type flagellates, differ from Trichomonadinae in certain important details. Among the features which T. foetus does not share with Trichomonadinae are the fine structure of the costa and of the undulating membrane, as well as several organelles not found in the latter subfamily. The costal base of Trichomonadinae is replaced in T. foetus and other Tritrichomonadinae by a comb-like structure, extending between the costa and the infrakinetosomal body. The suprakinetosomal body, connected to kinetosome #2 in the region of attachment of the sigmoid filaments, and the infrakinetosomal body, which appears to contribute to the proximal marginal lamella, are organelles evidently restricted to Tritrichomonadinae. The undulating membrane consists of 2 parts. The proximal part is a fold-like differentiation of the dorsal body surface, the dorsal part of which contains the proximal marginal lamella. The distal part of the undulating membrane, with no obvious physical connection to the fold, encloses the distal marginal lamella in its ventral, and the microtubules of the recurrent flagellum in its dorsal area. The organelle of T. foetus which by its size, certain structural characteristics, and relationship with the undulating membrane and some organelles, including the paracostal granules, is analogous to the costa of Trichomonadinae and of Trichomitopsis termopsidis (subfamily Tritrichomonadinae), conforms in the structure of its periodic cross-striations to that of the parabasal filaments of the latter organisms; its origin corresponds closely to that of parabasal filament 2 of Trichomonadinae.
A genetic basis for geographic variation in shell morphology in the bay scallop, Argopecten irradians

The bay scallop, Argopecten irradians, exhibits extensive variation in morphology among geographically separated populations, resulting in the recognition of three major subspecies (A. i. irradians, A. i. concentricus, A. i. amplicostatus). The extent to which morphological variation results from differing environmental conditions is unknown. In the present study, bay scallops from Massachusetts, North Carolina, Florida, and Texas were collected, spawned and the offspring reared in a common garden experiment to determine if scallops cultured under similar environmental conditions exhibited the morphology expected given the geographic origin of their parents. Significant differences among populations were indicated by ANOVA in both the wild-caught (13/14 morphological characters) and cultured (11/14 characters) scallops. Principal components analysis clustered wild-caught scallops according to geographic origin and cultured scallops according to geographic ancestry. The morphological characters most influential in resolving groups were plical width, plical spacing, number of plicae and valve convexity. Geographic variation in morphology apparently has a strong genetic basis, and reflects significant differentiation among disjunct populations of bay scallops.
Über Antimon(V)-bromchloride und ihre Stabilisierung durch Elektronendonatoren

Es wird uber die Stabilisierung von SbCl3Br2 mit Elektronendonatoren berichtet. Isoliert wurden 1:1-Verbindungen mit den Donatoren Diathylather, Tetrahydrofuran, Triphenylphosphoroxid und -sulfid. Bei Gegenwart von CCl4 addiert das Tetrahydrofuranaddukt 3 Molekeln CCl4. Die Bindungsverhaltnisse werden in bezug auf die Donatoreigenschaften diskutiert. Das Addukt SbCl3Br2 · OP(C6H5)3 wandelt sich in Nitrobenzol zu SbCl3Br2 · O2NC6H5 um. Dieses Addukt zeigt bei Zimmertemperatur im Verlauf von 15 h eine Umlagerung zu heteropolaren Verbindungen der allgemeinen Formel [SbClnBr4−n(O2NC6H5)2]+[SbClmBr6−m]− mit m + n = 6 und n = 1, 2, 3, 4. SbCl3Br2 may be stabilized by electron donors. Crystalline 1:1 adducts with diethyl ether, tetrahydrofurane, triphenylphosphine oxide and -sulphide were isolated. Their bonding properties, regarding the donor strengths, are discussed. The tetrahydrofurane adduct takes up three molecules of CCl4 in the presences of CCl4 · SbCl3Br2 · OP(C6H5)3 is converted in introbenzene into SbCl3Br2 · O2NC6H5 which, at room temperature, transforms in the course of 15 hours to heteropolar compounds of the general formula [SbClnBr4−n · (O2NC6H5)2]+[SbClmBr6−m]−, with m + n = 6 and n = 1, 2, 3, 4.
High voltage electron microscopy of the optic neuropile of the housefly, Musca domestica.

Synaptic cartridges of the first optic neuropile (lamina ganglionaris) of the housefly were examined by high voltage electron microscopy (HVEM). Stereo pairs (from thick, i.e., 0.25 μm, sections viewed at 1,000 kV) provided a three dimensional representation of cartridge neurons and clearly revealed the lateral spread, bifurcation and some functional associations of Type I (L1, L2) monopolar interneurons. Slightly proximal to cartridge neck level, pairs of retinular (R) axons made contact with each other and it appeared that R processes projected through the cleft between the Type I interneurons. No junctional modifications were seen between contiguous R axon terminals. The speculation was made that functional contact might exist between neighboring R axons prior to their extensive synapses with principal first order interneurons. Such alleged coupling between R axons would account for several electrophysiological findings from other laboratories. Modifications in EM technique applicable for HVEM were detailed. The value of obtaining thick serial sections and the use of the HVEM in expediting three dimensional reconstructions of neuropile were demonstrated.
Energy saving strategies in WiFi indoor localization

Despite extensive research on WiFi indoor localization, very few solutions are widely deployed, largely due to their high energy consumption. In this paper, we propose several energy saving strategies with varying localization accuracy and energy consumption tradeoffs in WiFi indoor localization. Instead of localizing every single device, these strategies exploit short range low-power communication technologies, to localize clusters of mobile devices, via a representative cluster head. We propose various cluster head selection algorithms that offer different trade offs between localization accuracy and power consumption. The outcome of this work provides insights into the effectiveness and cost of a particular strategy depending on the needs of the application requiring varying localization service levels.
The all-metal spin transistor

An entirely new kind of switching device is fabricated entirely from metals. The three-layer, three-terminal spin transistor behaves somewhat like a semiconductor bipolar transistor; though the physical operating principles differ. The emitter and collector layers of the spin transistor are ferromagnetic films. The base layer is a nonmagnetic metal, such as gold, copper, or silver. Being all-metal the device can be made much smaller than semiconductor transistors-less than 0.1 micrometer on a side. Although still a technological infant, the device has the electrical properties required by memory cells, current amplifiers, and logic circuits. A computer made only of metals seems quite possible. >
Conformational stability of ethylcyclopropane from Raman spectra, temperature dependent FT-IR spectra of xenon solutions and ab initio calculations

Abstract Infrared spectra (3500 to 400 cm−1) of xenon solutions of ethylcyclopropane, c-C3H5C2H5, at temperatures from −60 to −100°C have been recorded. In addition, Raman spectra of the liquid and polycrystalline phases have been obtained as well as infrared spectra of the gaseous phase. Spectroscopic evidence for the coexistence of the gauche and cis conformers of the title compound is found in the fluid phases. From the spectroscopic data, the enthalpy difference between the gauche and cis conformers has been estimated to be 385 cm−1 (1.10 kcal mol−1), with the gauche rotamer the more stable form. In the annealed solid phase, only the gauche conformer is found. Ab initio calculations have been carried with different basis sets up to MP 2 6-31 G , from which structural parameters, conformational stabilities, force constants, and vibrational frequencies have been determined. These calculations support the experimental conclusions and aid in the vibrational assignment of the normal modes. These results are compared to the corresponding quantities for some similar molecules.
A Stabilized Amplifier for Measurement Purposes

This paper describes a stabilized amplifier with an over-all amplification ratio that remains essentially constant in magnitude and phase for all changes in tube characteristics, line-voltage variations, and output load variations to be expected during normal operation. This stability is obtained by the introduction of two stabilizing circuits which act independently, yet are complementary when used together. During a period of eight weeks' use two such amplifiers with their associated indicating instruments maintained their original calibration within two-tenths per cent of full scale without readjustment.
Remembering Emma Lazarus

Breaking the Immigration Stalemate, a Report from the Brookings-Duke Immigration Policy Roundtable, offers practical suggestions for immigration reform. Stalemate, however, falls short both in identifying the underlying problems that warrant reform and in articulating broad national goals that immigration policy should achieve. One such goal, one that is part of our national heritage, would be to advocate for increased immigration as part of our arsenal for addressing global poverty.
A New Modular Indole Synthesis. Construction of the Highly Strained CDEF Parent Tetracycle of Nodulisporic Acids A and B

[reaction: see text] Construction of the highly strained CDEF parent tetracycle, a structural motif found only in the potent ectoparasiticidal agents (+)-nodulisporic acids A and B and related congeners, has been achieved via a new modular indole synthesis, exploiting a sequential Stille cross-coupling/Buchwald-Hartwig union/cyclization tactic. The new indole synthesis holds the promise of rapid assembly of diverse, highly substituted indoles possessing uncommon substitution patterns.
Gorgoderina attenuata: uptake and incorporation of tyrosine, thymidine, and adenosine.

Abstract In autoradiographic and scintillation counting studies, tritiated tyrosine, thymidine, and adenosine were found to be absorbed and incorporated by Gorgoderina attenuata in in vitro exposures of up to 12 hr. Tyrosine was incorporated into all tissues with the highest levels found in the intestinal epithelium. No evidence for selective incorporation of tyrosine into vitellaria was found. Thymidine was incorporated mainly into nuclei of gonial cells of the reproductive system and developing miracidia within eggs. Autoradiograms indicated assimilation of tyrosine and thymidine was highly variable among individual worms of a treatment group. Adenosine was absorbed and incorporated by worm tissues in large amounts within 3 hr. Variability of labeling on autoradiograms was not as great as with tyrosine and thymidine. Results of scintillation counting and grain counts of autoradiograms on ligated worms indicated all three compounds can enter the worm through the tegument. Adenosine was considered the best possible compound of the three to use for labeling cells for studies on the reproductive system.
A new synthetic use of nucleoside N1-oxides

The use of adenosine N/sup 1/-oxide derivatives to prevent intramolecular cyclization during nucleophilic displacement reactions on the sugar moiety is described. This new synthetic use of N/sup 1/-oxides is illustrated by the synthesis of 5'-O-(p-toluenesulfonyl)-2',3'-O-isopropylideneadenosine N/sup 1/-oxide (6) and subsequent displacement of the 5' substituent with iodide or azide under conditions which lead exclusively to N/sup 3/..-->..5' intramolecular cyclization in the absence of the N/sup 1/-oxide. Similarly, reaction of 2',3'-O-isopropylideneadenosine N/sup 1/-oxide with methyltriphenoxyphosphonium iodide produces 5'-iodo-5'-deoxy-2',3'-O-isopropylideneadenosine N/sup 1/-oxide (7) with no observable cyclization. In addition, 2',3'-anhydroadenosine N/sup 1/-oxide (17) is shown to be stable under conditions that lead to complete N/sup 3/..-->..3' intramolecular cyclization in the upprotected 2',3'-anhydroadenosine (14). Reduction of the N/sup 1/-oxide to produce the parent nucleoside is readily achieved by using hexachlorodisilane or by hydrogenating over Raney nickel. The mechanistical rationale and implications for additional nucleoside transformations are discussed. 2 tables, 1 figure.
Thermoregulatory behaviour of the primitive arthropod Limulus polyphemus in an electronic shuttlebox

Abstract 1. 1.|Ten Limulus polyphemus were tested individually for 3-day periods in an electronic shuttlebox (Ichthyotron) to characterize their thermoregulatory performance. 2. ]2.|With access to a potential temperature range of 0–50°C, the Limulus voluntarily occupied a range of 15–40°C without ill effect. 3. ]3.|The mean thermal preferendum of these animals was 29.4°C ( S . E . M . = 0.19° C ; S . D . = 5.27° C ; median 29°C; midpoint 27.5°C; mode 27°C; Pearson's skewness coefficient = +0.46). 4. 4.| Limulus is capable of thermoregulatory behaviour, but is less precise in terms of voluntarily occupied range (a 25°C span) than aquatic ecothermic animals previously tested; it is quite eurythermal in tolerance, and can endure 40°C for at least 8 h.
Sickle cell anemia and severe infections due to encapsulated bacteria

Overwhelming infections caused by encapsulated bacteria are an important cause of morbidity and death in children with sickle cell anemia. The most important contributing factors to this increased susceptibility to infections are an opsonophagocytic defect due to an abnormality of the alternate pathway of complement activation, a state of functional hyposplenia, and a lack of specific circulating antibodies as a developmental phenomenon. If the inordinately high, early mortality rate associated with sickle cell anemia is to be prevented, early diagnosis of affected infants is crucial. Prophylactic therapy with penicillin has been advocated in recognition of the fact that a majority of the causative organisms are sensitive to penicillin. However, no controlled studies have proved the effectiveness of such therapy. Immunization with broadly polyvalent vaccines against Streptococcus pneumoniae, Haemophilus influenzae type b, and Neisseria meningitidis may ultimately represent the most effective way to reduce the incidence of catastrophic infections.
10.2.1 Improving the Practice of Systems Engineering at JPL

JPL has been investing in a focused effort to improve its practice of systems engineering. The Lab's senior management formed the Systems Engineering Advancement (SEA) Project in order to significantly advance the practice and organizational capabilities of systems engineering at JPL on flight projects and ground support tasks. This paper describes JPL's approach to improving the practice of systems engineering. It describes the general approach used and how they address the three key aspects of change: people, process and technology. It describes plans and progress in each of those three dimensions of change and concludes with some initial work in acquiring systems engineering metrics.
Electronic structure of CePd3 from resonant photoemission and optical reflectivity spectra

Optical reflectivity and resonant photoemission measurements on CePd3 yield a 4f binding energy Ef between 0.7 and 1.0 eV and set an upper limit of 0.3 eV on a surface shift of Ef. The 4f halfwidth at half maximum δ is between 0.5 and 0.8 eV. The spin fluctuation energy Γ = 20 meV is successfully related to Ef and δ by the Kondo impurity Ansatz.
Sequence Motifs in the Replicator Protein of Parvovirus MVM Essential for Nicking and Covalent Attachment to the Viral Origin: Identification of the Linking Tyrosine

Abstract Parvoviral DNA replication has many features in common with prokaryotic rolling circle replication (RCR), including the pivotal role of an initiator protein which introduces a site-specific, single strand nick into a duplex origin sequence. In this process, the protein becomes covalently attached to the new 5′ end of the DNA, while making available a 3′ hydroxyl to prime de novo synthesis. Sequence comparisons of prokaryotic RCR initiators has revealed a set of three common motifs, two of which, a putative metal coordination site and a downstream active-site tyrosine motif, could be tentatively identified in parvoviral replicator proteins. We have introduced mutations into the NS1 gene of the murine parvovirus minute virus of mice (MVM), in the putative metal coordination site at H129, and into the three candidate tyrosine motifs at Y188, Y197, and Y210. Histidine-tagged mutant proteins were expressed in HeLa cells from recombinant vaccinia virus vectors and partially purified. None of the mutant proteins were able to initiate replication of origin-containing plasmids in vitro, and each showed impaired site-specific binding to the viral origin, with Y188 and Y197 being most severely defective. If this deficiency was minimized using low salt conditions, however, Y188 and Y197 mutant proteins were able to nick and become covalently attached to origin DNA, whereas Y210 and H129 mutant proteins were not, suggesting that the latter residues are part of the catalytic site of the NS1 nickase. Transfer of [32P]phosphate from substrate DNA to NS1, followed by cyanogen bromide cleavage of the complex, gave the single, labeled peptide consistent with Y210 being the linking tyrosine.
Hydrodynamics of Superfluid Helium below 0.6 °K.I. Viscosity of the Normal Fluid

The normal-fluid viacosity of superflilid He/sup 4/ has been calculated for temperatures below about 0.6DEK. The calculation assumes that the dominant scattering mechanism is thc three-phonon process in the first order of penturbation theory. This contrasta with the previous calculation of Landau and Khalatnikoy, who assumed a seceond-order process involving four phonons. The theory is compared with the experiments of Whitworth on heat flow through tubes. Good agreement is obtained, as regards both the magnitude of the viscosity and its temperatur dependence. (auth)
Hydrophobic forces in thin water films stabilized by dodecylammonium chloride

A thin film balance of Scheludko-Exerowa type was used to determine equilibrium film thicknesses of dodecylammonium chloride (RNH3Cl) solutions. The data were analyzed in view of the extended DLVO theory, which considers electrostatic, van der Waals, and hydrophobic forces. The hydrophobic force was represented as a power law which is of the same form as for the van der Waals force, so that its constant K232 can be directly compared with the Hamaker constant, A232. The results showed that at low surfactant concentrations, K232 is positive and decreases with increasing surfactant concentration, suggesting that hydrophobic force plays an important role in thin films. When the K232 versus concentration plot was extrapolated to very dilute solutions, K232 approaches 10(-17) J, which is approximately 270 times larger than A232. When the surfactant concentration was increased above 2 x 10(-3) M, however, K232 becomes negative, indicating that hydration force appears at high surfactant concentrations. These results suggest that air bubbles are hydrophobic and the hydrophobicity decreases with increasing surfactant concentration. A TFB was used to obtain a disjoining pressure isotherm at 10(-3) M RNH3Cl in the presence of 10(-4) M NaCl. The results can be fitted to the extended DLVO theory with K232 = 6 x 10(-19) J. Consideration of hydrophobic force predicted a rupture thickness larger than predicted using the DLVO theory, but is substantially smaller than the experimental result. This discrepancy may be ascribed to the hydrodynamic force operating in the film thinning process. Copyright 1999 Academic Press.
The pentose phosphate pathway in cystic fibrosis erythrocytes.

Abstract Glucose-6-phosphate dehydrogenase (G6PD), NADP and NADPH were compared in red blood cells (rbc's) of cystic fibrosis (CF) patients and sex and age matched controls. G6PD activity was higher in CF rbc's (P = .03). NADPH/NADP ratios were decreased in CF rbc's (P= .003). These findings are viewed in terms of an increased cellular need for NADPH generated by the pentose phosphate pathway (PPP). They indicate also that in terms of NADP CF rbc's are in a more oxidized state than are non CF rbc's.
Correlation Estimates from Discontinuous Data

Abstract Continuous data of 40,416 first-lactation Guernsey records of milk, fat, and fat percent were stratified into categories to simulate discrete traits. Phenotypic correlations on the continuous scale generally were underestimated in absolute value when one or both traits were discrete. Underestimation became greater as the number of discrete classes decreased and became substantial (50%) when data on both traits were binomiallike. Genetic correlations on the continuous scale from paternal halfsibs were closely estimated when one or both traits were discrete. However, there were slight indications of overestimations, and fewer categories caused greater overestimation. Overestimation was greater when the underlying continuous genetic correlation was negative or small positive than when the correlation was high positive. When the underlying correlation was high positive, neither over- nor underestimation occurred. In all cases, the fewer the number of categories, the greater the sampling variation in correlation estimates.
Magneto-fluid-mechanics free convection turbulent flow

The present work is an experimental study of the influence of a uniform magnetic field on the structure of a free convection turbulent boundary layer in a conducting fluid. The boundary layer was formed along the heated vertical wall of a cell. The applied magnetic field was normal to the wall. The measured mean temperature profiles, temperature turbulent intensity distributions, and temperature spectra along the wall, indicated that transition from turbulent to laminar flow occurs at a constant value of the ratio (Rayleigh number)/(Hartmann number). The study of the recorded spectra indicated that the presence of the magnetic field enhances the mechanism of turbulent suppression due to the buoyancy forces. Finally, a possible mechanism by which turbulence is suppressed by the presence of a magnetic field is discussed.
Evidence for the proenkephalin processing enzyme prohormone thiol protease (PTP) as a multicatalytic cysteine protease complex: activation by glutathione localized to secretory vesicles.

The cysteine protease known as “prohormone thiol protease” (PTP) has been identified as a major proenkephalin processing enzyme in secretory vesicles of adrenal medulla (known as chromaffin granules). This study provides the first demonstration that PTP exists as a multicatalytic cysteine protease complex that can be activated by endogenous glutathione present in chromaffin granules. The high molecular mass nature of PTP, of approximately 185 kDa, was demonstrated by elution of a single peak of 35S-enkephalin precursor cleaving activity by Sephacryl S200 gel filtration chromatography and by a single band of 35S-enkephalin precursor cleaving activity detected on radiozymogram gels under native buffer conditions. Importantly, when 0.1% SDS was included in radiozymogram gels, PTP activity was resolved into three bands of proteolytic activity with apparent molecular masses of 88, 81, and 61 kDa. These activities were all cysteine proteases, since they were inhibited by the cysteine protease inhibitor E-64c bu...
Photochemical reactivity of dissolved lignin in river and ocean waters

The photochemical reactivity of dissolved lignin and photobleaching of dissolved organic matter (DOM) were examined in riverine and open-ocean water samples. Approximately 75% of the total dissolved lignin in Mississippi River water was lost during 28 d of incubation in sunlight, mostly due to photooxidation. The remaining fraction of dissolved lignin was much less susceptible to photooxidation. About 90% of the dissolved lignin in river water was present as high-molecular-weight (HMW, >1,000 Dalton) DOM. However, after exposure to sunlight, about 80% of the remaining lignin was present as low-molecular-weight (LMW, <1,000 Dalton) DOM. An absolute increase in concentration of LMW lignin provided direct evidence for the phototransformation of macromolecular DOM to smaller molecules. The composition of riverine dissolved lignin also changed dramatically during photooxidation. The abundance of syringyl relative to vanillyl phenols decreased twofold, while concentrations of vanillic acid relative to vanillin, (Ad/Al)v, increased fourfold. The increase in (Ad/Al)v was found exclusively in the photooxidized LMW DOM. The photochemically altered composition of riverine dissolved lignin was consistent with the composition of oceanic dissolved lignin, The dissolved lignin in HMW DOM from the equatorial Pacific Ocean was highly resistant to photooxidation. These findings suggest that photochemical reactions play a prominent role in determining the composition and reactivity of terrigenous DOM in the ocean,
Individualism—Collectivism, Coping Styles, and Stress in International and Anglo‐australian Students: A Comparative Study

Abstract The present study was designed to test the hypothesis that culture mediates coping styles and that acculturative stress will be attenuated by the use of culturally relevant coping strategies. A cross-sectional sample of Asian and Anglo-Australian students in Australia was used in the study. Newly arrived Asian students resident in Australia less than 6 months (Asian 1), Asian students resident in Australia for more than 6 months but less than 3 years (Asian 2), Asian students resident in Australia more than 3 years (Asian 3), Asian-Australians, and Anglo-Australians (N = 112) completed the Perceived Stress Scale (Cohen, Kamark, & Mermelstein, 1983) and the COPE scale (Carver, Scheier, & Weintraub, 1989). Results indicate that Asian students within their first 6 months of residency in Australia are highest in levels of perceived stress and also tend to employ collectivist coping strategies more than any other group. Anglo-Australians are lowest on measures of perceived stress and tend towards the ...
Red herrings: Some thoughts on the meaning of zero-probability events and mathematical modeling

Abstract Kicking off the discussion following Savage's presentation at the 1952 Paris colloquium, Arrow raised what he considered to be a difficulty with the intuitive interpretation of Savage's theorem. It suggests that decision makers strictly prefer betting on an event of measure zero over betting on a proper subset of that event. Within the realm of the revealed-preference methodology and limited verifiability, Arrow's difficulty is a red herring: the problem he poses has its origin in the technical aspects of Savage's model and not in its substantive aspect.
Paleoecology of whale-fall habitats from deep-water Oligocene rocks, Olympic Peninsula, Washington state

Fossil mollusks associated with eight Oligocene whales from the Makah and Pysht Formations on the northwestern part of the Olympic Peninsula, Washington, suggest that whale carcass sulfide production supported small numbers of some chemosymbiotic invertebrates as early as 30 million years ago. Thyasirid and modiolid bivalves usually dominate these very localized molluscan assemblages; lucinid and nuculanid bivalves, scaphandrid, naticid, and buccinid gastropods are rarely present; brachiopods were found once. These fossils include, tentatively, the first fossil record for the bivalve genus Idasola, and the first record of the bivalve Thyasira peruviana Olsson, outside of probable cold-seep deposits in South America. Strata surrounding the fossil whales contain low diversity megafaunas that include rare deep-water gastropods and bivalves, large isopods, and localized cold-seep communities. The whale-fall assemblages differ significantly because of the presence of Idasola? sp. and Thyasira peruviana? and the absence of vesicomyid bivalves. Vertebrate carcasses have probably not contributed significantly to the dispersal of cold-seep and hydrothermal vent invertebrates. Seep/vent communities were well established much earlier than the evolution of cetaceans, and seep/vent invertebrates have not been found with carcasses of other large vertebrates.
The rate of coupling of diazotized sulfanilic acid with bilirubin.

Abstract The rate of coupling of the unconjugated bilirubin with diazotized sulfanilic acid was measured spectrophotometrically. The rate of reaction best corresponded to that calculated by means of the usual bimolecular equation. The conjugated bilirubin coupled too rapidly with the diazotized sulfanilic acid, and the rate of coupling could not be studied by the above method.
Elastic body spline based image segmentation

Elastic body splines (EBS) belonging to the family of 3D splines were recently introduced to capture tissue deformations within a physical model-based approach for non-rigid biomedical image registration [1]. EBS model the displacement of points in a 3D homogeneous isotropic elastic body subject to forces. We propose a novel extension of using elastic body splines for learning driven figure-ground segmentation. The task of interactive image segmentation, with user provided foreground-background labeled seeds or samples, is formulated as learning an interpolating pixel classification function that is then used to assign labels for all unlabeled pixels in the image. The spline function we chose to model the supervised pixel classifier is the Gaussian elastic body spline (GEBS) which can use sparse scribbles from the user and has a closed form solution enabling a fast on-line implementation. Experimental results demonstrate the applicability of the GEBS approach for image segmentation. The GEBS method for interactive foreground image labeling shows promise and outperforms a previous approach using the thin-plate spline model.
Beta-helical fibrils from a model peptide

A synthetic peptide, KLEG13 (Ac-KLKLKLELELELG-NH2), composed of alternating bulky hydrophilic and hydrophobic amino acid residues formed clear, viscous dispersions of fibrils in saline solutions. The fibrils had a uniform diameter of 2 nm as measured on electron micrographs of negatively stained preparations. 13C solid-state nuclear magnetic resonance spectroscopy of the fibrils indicated the presence of a beta-conformation. Circular dichroic spectra of the dispersion of fibrils were essentially identical to the calculated spectrum of a 100% beta-helix. Space-filling CPK models of a proposed beta-helical conformation of the peptide, in which the leucine side chains form a hydrophobic core and the hydrophilic lysine and glutamate side chains extend outwards from the helix, had a diameter consistent with the observed 2-nm diameter of the fibrils. This study may have implications regarding the structure of amyloid fibrils.
Dusty debris disks: First light from exosolar planetary systems

For stars with ages ≥ 10 Myr, circumstellar disks are dominated by a population of optically thin dust grains most likely associated with the erosion of a planetesimal population in a system that may have also formed planets. The key goal of this chapter is to provide a core introduction to circumstellar debris disks that will allow the reader to more easily grasp the vast literature. We review key concepts involving the thermal and scattered light detection of debris disks, stellar age determinations, dust destruction mechanisms, and the connection between debris disks and exosolar planets. The material is presented at a level suitable for the non-astronomy graduate students attending the Les Houches winter school, but also includes tables and previously unpublished figures that will interest advanced astronomers.
Role of Defective Oct-2 and OCA-B Expression in Immunoglobulin Production and Kaposi's Sarcoma-Associated Herpesvirus Lytic Reactivation in Primary Effusion Lymphoma

Primary effusion lymphoma (PEL) is a distinct type of B-cell non-Hodgkin lymphoma characterized by the presence of Kaposi's sarcoma-associated herpesvirus (KSHV/human herpesvirus 8). Despite having a genotype and gene expression signature of highly differentiated B cells, PEL does not usually express surface or cytoplasmic immunoglobulin (Ig). We show the lack of Oct-2 and OCA-B transcription factors to be responsible, at least in part, for this defect in Ig production. Like Ig genes, ORF50, the key regulator of the switch from latency to lytic reactivation, contains an octamer motif within its promoter. We therefore examined the impact of Oct-2 and OCA-B on ORF50 activation. The binding of Oct-1 to the ORF50 promoter has been shown to significantly enhance ORF50 transactivation. We found that Oct-2, on the other hand, inhibited ORF50 expression and consequently lytic reactivation by competing with Oct-1 for the octamer motif in the ORF50 promoter. Our data suggest that Oct-2 downregulation in infected cells would be favorable to KSHV in allowing for efficient viral reactivation.