cssi/SciSciGPT-SciSciNet huggingface dataset:
Dimethylsulphoniopropionate (DMSP) in Spartina alterniflora Loisel

Abstract Dimethylsulphoniopropionate (DMSP) in saltmarsh grasses of the genus Spartina has been suggested to act as a compatible osmolyte or as an intermediary product of a sulphide detoxification mechanism. Investigations of Spartina alterniflora Loisel. plants collected from salinity and sulphide gradients along a South Carolina river showed that DMSP concentrations were not correlated with either salinity or sulphide concentrations in soil porewater. This suggested that DMSP is neither a compatible osmolyte nor involved in sulphide detoxification. Greenhouse experiments were also performed, investigating the effects of sulphate, sulphide and ammonium nitrate on DMSP concentrations in the plants. Only ammonium nitrate affected DMSP concentrations, which decreased in the shoots upon increasing nitrogen amendments. It is suggested that nitrogen stimulates biomass production, leading to dilution of DMSP concentrations. Ammonium nitrate amendments also decreased the fraction of total sulphur in the shoots allocated to DMSP, which ranged between 36 and 86%. The data suggest that nitrogen plays a key role in determining DMSP concentrations in plants of the genus Spartina and that DMSP is not involved in a sulphide detoxifying mechanism. Alternative hypotheses for the functions of DMSP in Spartina alterniflora are suggested.
Synthesis and reactivity of allyl nickel(II) N‐heterocyclic carbene enolate complexes

Two new N-heterocyclic carbene enolate nickel(II) allyl complexes have been prepared and their activity towards ethylene polymerization was investigated. It was found that in the presence of diethyl zinc, the carbene enolate complex bearing a nitro substituent produces highly linear polyethylene of modest molecular weight and high polydispersity. The influence of the reaction parameters on catalytic activity and the characteristics of the resulting polymer were investigated through systematic variation of the time, temperature, and diethyl zinc concentration.
Selection of plant parts by Depressaria multifidae (Lep., Oecophoridae) on its seasonally‐restricted hostplant, Lomatium grayi (Umbelliferae)

. 1 Depressaria multifidae Clarke feeds on a broader variety of Umbelliferae plant parts than other Depressaria species. 2 Early instar larvae feed in the sheaths surrounding floral buds and leaves. Later instar larvae feed in the sheaths and floral stems and on flowers and leaves. 3 Floral stems bored by larvae had significantly larger basal stem diameters than floral stems that were not bored. Smaller stems usually have umbels with only male flowers, and wither after flowering, too soon for larvae to complete development. In contrast, larger stems often have umbels with some hermaphroditic flowers, which remain green and erect long enough for larvae to complete development. Hence, selection may favour larvae that bore only in relatively large stems. 4 In the laboratory, larvae fed sheaths with enclosed floral buds, flowers, or leaves all pupated at the same weight, but larvae fed floral stems pupated at a significantly lower weight. Larval and pupal development time was the same on all plant parts. 5 In the field, larvae restricted to a single umbel throughout development pupated at the same weight as those restricted to a single leaf. 6 Unlike in other Depressaria species, nitrogen levels only partly correspond to the pattern of use of plant parts in D.multifidae. Nitrogen values varied as follows: floral buds > immature leaves ≥ flowers > floral stalks > sheaths excluding floral buds or leaves. 7 The broad variety of plant parts used by D.multifidae may result partly from the problem of feeding on a small, seasonally restricted hostplant; the greater use of sheaths and floral stems than in other Depressaria species may result from selection for safety from parasites or predators. 8 The results for D.multifidae indicate that the way in which an insect feeds on a plant species can vary broadly even at a single site.
Expression in Escherichia coli of cytoplasmic portions of the cystic fibrosis transmembrane conductance regulator: apparent bacterial toxicity of peptides containing R-domain sequences.

Abstract Large peptide segments (148–479 amino acids) of the cystic fibrosis transmembrane conductance regulator, which are projected to represent cytoplasmic portions of this large membrane protein, were expressed in Escherichia coli using two T7 RNA polymerase vectors, pET11a and pRSET. Five of the nine peptides were readily expressed at high levels (15–35 mg/liter) and one at an intermediate level (10 mg/liter), but three could not be expressed at >1.5 mg/liter regardless of efforts to further optimize the system. Preinduction testing of these latter plasmids failed to demonstrate any plasmid instability, while bacterial survival was drastically curtailed upon induction, beyond that observed with the other plasmids. Peptides containing the second half of exon 13 (residues 700–830; R domain) appear to be especially toxic to the expressing bacteria. Peptides including this hydrophilic segment may be inhibiting the bacterial permeases which are known to be homologous to other portions of CFTR.
Elastic arches with large elevation. Singularly perturbed problem of nonlinear elasticity

In this paper we examine the asymptotic expansion of a three-dimensional displacement field defined over a slender, bowlike domain whose shape corresponds to a thin arch. We show that it is possible to derive from the principles of virtual work two families of arch equations whose forms vary with the scale of external forces and the curvature of the arch. The first family of models, for relatively small curvatures, is described by singularly perturbed ordinary differential equations. The second family, when the curvature of the original arch is large, is described by two-dimensional partial differential equations whose form depends on the shape of the cross-section of the solid arch.
Single Setting Bilateral Laparoscopic Orchiopexy for Bilateral Intra-Abdominal Testicles

Purpose: The laparoscopic surgical approach to unilateral intra-abdominal testis has replaced the open approach at several large centers. There is considerable literature on experience with unilateral intra-abdominal testes but little on the management of bilateral intra-abdominal testes. We assessed the feasibility and safety of performing single setting bilateral laparoscopic orchiopexy in boys with bilateral intra-abdominal testes.Materials and Methods: A single surgeon experience was reviewed. The surgical technique was similar in all cases and on each side, including infra-umbilical access, diagnostic evaluation, peritoneal mobilization lateral to the spermatic vessels and inferior to the vas deferens, gubernacular transection, and a decision for or against a Fowler-Stephens procedure and testis relocation into the scrotum with fixation. Followup consisted of physical examination 14 days, 6 months and 1 year postoperatively, when testicular position and size were assessed. Intraoperative and postoper...
Viscous transonic airfoil workshop results using ARC2D

Computations have been performed in response to the Viscous Transonic Airfoil Workshop associated with the AIAA 25th Aerospace Sciences Meeting (January 1987). The purpose of the workshop is to establish the capabilities of various methods for computing viscous flowfields for a range of conditions and geometries. The results of the test cases will demonstrate the capabilities of the methods in predicting both aerodynamic trends and flowfield details. ARC2D, a well-established Navier-Stokes code, was used to compute the flowfields for the designated airfoils, Mach numbers, angles of attack and other specifications of the Workshop committee.
Fluoride Toxicity in the Chick

Abstract INTRODUCTION YOUNG chicks and adult poultry have exhibited higher tolerance levels for fluoride than most mammalian species. The chick’s ability to tolerate larger quantities of fluoride is credited to a lower intestinal absorption, and perhaps a more effective elimination of fluoride (Haman et al., 1936; Phillips et al., 1935). Kick et al. (1933), found that chicks could not tolerate fluoride levels higher than 3,600 p.p.m. in the diet. Gerry et al. (1947), found that in the growing chick the maximum safe dietary level of fluoride was 300 to 400 p.p.m. of fluoride when fed as rock phosphate. Phillips et al. (1935), demonstrated that the growth of chicks was inhibited by feeding 70 mg. of fluoride per kg. of body weight per day. The authors postulated that this level of fluoride caused growth inhibition by restriction of feed consumption. In addition, intraperitoneal injections of fluoride also restricted feed consumption. The restriction…
Some fundamentals of cooled mirrors for synchrotron radiation beam lines

We present an analysis using conventional heat-transfer theory of a common type of synchrotron-radiation-beam-line mirror with rectangular cooling channels. The analysis leads to a simple analytic expression for the slope error, which enables the distortion performance to be estimated in practical situations. It also provides an understanding of the effect of the various parameters on the goodness of the cooling process and an insight into the underlying physics. The analysis is applied to determining the design steps needed to achieve low slope errors and/or high-heat-removal rates with this type of mirror. The slope-error performance of various materials in a specific design are compared and the best performance is obtained from (in order) invar, silicon, and silicon carbide. {copyright} {ital 1996 Society of Photo{minus}Optical Instrumentation Engineers.}
Issues in computer-based test interpretive systems

Abstract This article presents issues sorrounding the review of computer based test interpretive systems. The Buros Institute of Mental Measurements is now producing reviews dedicated to the evaluation of computer-based test interpretation (CBTI) systems.
Targeted disruption of expression site-associated gene-1 in bloodstream-form Trypanosoma brucei☆

Each variant surface glycoprotein (Vsg) expression site (ES) in bloodstream-form Trypanosoma brucei is a polycistronic transcription unit containing several distinct expression site-associated genes (esag), in addition to a single vsg gene. esag1 genes from different ESs encode a highly polymorphic family of membrane-associated glycoproteins, whose function is unknown. In the hope of producing a phenotype that could indicate a function, we disrupted the esag1 genes in two ESs by targeted insertion of a hygromycin phosphotransferase gene. Our failure to produce an obvious phenotype prompted us to search for other esag1 transcripts. RNA from the mutant trypanosomes hybridized with an esag1-specific oligonucleotide. Cloning and sequencing of mRNA from both mutant and wild-type cells showed that several esag1 family members were expressed, each at a much lower level than the esag1 transcript from the active ES in wild-type trypanosomes. Long-range DNA mapping showed that these additional esag1 genes, some of which contained premature translation-termination codons, most probably originate from chromosomal-internal genes and pseudogenes. We have therefore been unable to determine whether esag1 is an essential gene, or what function it fulfils, or whether any competent Esag1 protein is expressed in the mutant trypanosomes.
Characterization of a laser-generated LiAg plasma plume

Time- and spatially-resolved spectroscopy in conjunction with detailed modeling constitutes a powerful technique for the understanding of plasma plume dynamics. To this end, in a series of experiments performed at Sandia National Laboratories, laser-generated LiAg plasma plumes were produced by irradiation of solid targets using a Nd laser. Time- and spatially-resolved (along a direction normal to the target's surface) optical spectra were recorded with a framing spectrograph. In order to limit gradients along a direction perpendicular to the target normal, targets with strips of LiAg coated on top of Pt were used. The PT plume collisionally confines the LiAg, thus reducing the LiAg lateral expansion. This technique allows a better characterization of the LiAg plasma. The spectra displays line transitions in Li and Ag atoms, and evidence of ions in the plume is suggested by the presence of forbidden lines and Stark-broadened line shapes. A spectroscopic model based on collisional-radiative atomic kinetics, detailed line shapes, and radiation transport calculations is used to interpret the data. From this analysis temperature, density and ionization in the plume as a function of time and position along the normal to the target surface can be extracted.
Steady-state optical spin polarization. Theory of the high field anisotropic ESR intensity

Abstract The effects of anisotropic formation and depletion ISC processes on the electron spin polarization of the short lived triplet states of spiropyrans are calculated using a density matrix theory.
Correction for Finite Quenching Rates in Shock-Induced Methane Pyrolysis

N this study, the feasibility of using a simple shock tube, without modifications to enhance the quenching rate, is explored. Such a simple shock tube is used to study the pyrolysis of methane as a step in studying reaction rates of hydrocarbons in, processes involving combustion and formation of air pollutants. The shock tube was operated in the tailored interface mode, and the reaction temperature ranged from 1,650 to 2,100 K, with a total reaction pressure up to 6.4xlO5 Pascal.The chemical reaction occurred behind the reflected shock wave, near the end wall of the test section. A sampling system was developed to allow a sample of product gas to be withdrawn from the test section before it was contaminated by the driver gas. A correction for finite quenching rate was developed and applied in this study as well as an error analysis. Contents The driven section of the shock tube was a rectangularshaped aluminum duct 8.54 m long. The inside dimensions were 7.62 x 15.22 cm. The driver section was a cylindrical tube 1.83 m long with an inside diameter of 17.8 cm. Further details of this shock tube are included in Ref. 1. The rate constants for the methane pyrolysis reaction reported in the literature differ from one another significantly. 2-6 The most recent study6 of this reaction in the shock tube was accomplished using optical methods to follow the progress of the reaction. The rate constant from that study is nearly an order of magnitude smaller than that reported in earlier studies in which the direct sampling of the reaction products was used. To summarize the results known to data on the pyrolysis of methane, it is clear that the reaction follows first-order kinetics with an apparent activation energy of 398±42 x 10 "3 J/mol (95 ± 10 kcal/mol) and a frequency factor of 2.5±1 x 1013. There does appear to be some pressure effect on the reaction rate, although there is not complete agreement on the extent. A satisfactory reaction mechanism has yet to be established, particularly at temperatures below 2,100 K. Sampling System: The progress of reactions studies in this investigation followed by extracting from the shock tube a quenched sample of the reaction gas mixture at a certain time and analyzing it by means of a gas chromotograph to determine its composition. The sampling system to accomplish this
Spatial proximity amplifies valence in emotional memory and defensive approach-avoidance

In urban areas, people often have to stand or move in close proximity to others. The egocentric distance to stimuli is a powerful determinant of defensive behavior in animals. Yet, little is known about how spatial proximity to others alters defensive responses in humans. We hypothesized that the valence of social cues scales with egocentric distance, such that proximal social stimuli have more positive or negative valence than distal stimuli. This would predict enhanced defensive responses to proximal threat and reduced defensive responses to proximal reward. We tested this hypothesis across four experiments using 3-D virtual reality simulations. Results from Experiment 1 confirmed that proximal social stimuli facilitate defensive responses, as indexed by fear-potentiated startle, relative to distal stimuli. Experiment 2 revealed that interpersonal defensive boundaries flexibly increase with aversive learning. Experiment 3 examined whether spatial proximity enhances memory for aversive experiences. Fear memories for social threats encroaching on the body were more persistent than those acquired at greater interpersonal distances, as indexed by startle. Lastly, Experiment 4 examined how egocentric distance influenced startle responses to social threats during defensive approach and avoidance. Whereas fear-potentiated startle increased with proximity when participants actively avoided receiving shocks, startle decreased with proximity when participants tolerated shocks to receive monetary rewards, implicating opposing gradients of distance on threat versus reward. Thus, proximity in egocentric space amplifies the valence of social stimuli that, in turn, facilitates emotional memory and approach-avoidance responses. These findings have implications for understanding the consequences of increased urbanization on affective interpersonal behavior.
The Rationale for Targeting the NAD/NADH Cofactor Binding Site of Parasitic S-Adenosyl-L-Homocysteine Hydrolase for the Design of Anti-Parasitic Drugs

Trypanosomal S-adenoyl-L-homocysteine hydrolase (Tc-SAHH), considered as a target for treatment of Chagas disease, has the same catalytic mechanism as human SAHH (Hs-SAHH) and both enzymes have very similar x-ray structures. Efforts toward the design of selective inhibitors against Tc-SAHH targeting the substrate binding site have not to date shown any significant promise. Systematic kinetic and thermodynamic studies on association and dissociation of cofactor NAD/H for Tc-SAHH and Hs-SAHH provide a rationale for the design of anti-parasitic drugs directed toward cofactor-binding sites. Analogues of NAD and their reduced forms show significant selective inactivation of Tc-SAHH, confirming that this design approach is rational.
Vision Based Iterative Learning Control for a Roll to Roll Micro/nano-manufacturing System

Abstract Fabrication of nano/micro-scale functional devices oftentimes involves multiple steps. In the context of a continuous or semi-continuous manufacturing process, each fabrication step is performed successively in multiple localized zones. As the substrate or the web traverses downstream in the process flow, proper registration of the pre-existing features is necessary prior to entering the next fabrication zone in order to accurately complement previous manufacturing steps. By performing a direct observation of the pre-existing feature using machine vision, the uncertainty of the feature location can be circumvented. In this paper, a two-layer feedback architecture with a vision sensor in the outer loops is used to visually servo the pre-existing feature on the web. Additionally, the feedback controller is augmented with Norm Optimal Iterative Learning Control (NOILC) to improve the position tracking and tension regulation of the web. Simulation and experimental results show the advantages of implementing NOILC in the R2R system.
Integrity of the yeast mitochondrial genome, but not its distribution and inheritance, relies on mitochondrial fission and fusion

Mitochondrial DNA (mtDNA) is essential for mitochondrial and cellular function. In Saccharomyces cerevisiae, mtDNA is organized in nucleoprotein structures termed nucleoids, which are distributed throughout the mitochondrial network and are faithfully inherited during the cell cycle. How the cell distributes and inherits mtDNA is incompletely understood although an involvement of mitochondrial fission and fusion has been suggested. We developed a LacO-LacI system to noninvasively image mtDNA dynamics in living cells. Using this system, we found that nucleoids are nonrandomly spaced within the mitochondrial network and observed the spatiotemporal events involved in mtDNA inheritance. Surprisingly, cells deficient in mitochondrial fusion and fission distributed and inherited mtDNA normally, pointing to alternative pathways involved in these processes. We identified such a mechanism, where we observed fission-independent, but F-actin–dependent, tip generation that was linked to the positioning of mtDNA to the newly generated tip. Although mitochondrial fusion and fission were dispensable for mtDNA distribution and inheritance, we show through a combination of genetics and next-generation sequencing that their absence leads to an accumulation of mitochondrial genomes harboring deleterious structural variations that cluster at the origins of mtDNA replication, thus revealing crucial roles for mitochondrial fusion and fission in maintaining the integrity of the mitochondrial genome.
The ATP dependence of a ouabain-sensitive sodium efflux activated by external sodium potassium and lithium in human red cells

The stimulation of ouabain-sensitive Na+ efflux by external Na+, K+ and Li+ was studied in control and ATP-depleted human red cells. In the presence of 5 mM Na+, with control and depleted cells, Li+ stimulated with a lower apparent affinity than K+, and gave a smaller maximal activation than K+. The ability of Na+, K+ and Li+ to activate Na+ efflux was a function of the ATP content of the cells. Relative to K+ both Na+ and Li+ became more effective activators when the ATP was reduced to about one tenth of the control values. At this low ATP concentration Na+ was absolutely more effective than K+.
Derivations and automorphisms of matrices symmetric relative to a canonical involution

In response to questions posed by physicists concerned with building algebraic models, we investigated in [I] derivations and automorphisms of Mn(A), n x n matrices with entries in an arbitrary (not necessarily associative) algebra c-l with identity 1. Included in that study were results on the derivations and automorphisms of algebras obtained from M,(A) using the Jordan product x oy = +(~y + ye) and the Lie product [xy] = xy yx. This present paper continues in a similar vein, but focuses attention on the algebra H,(A, a) of matrices in &fn(A) which are symmetric relative to an involution 0 fixing the diagonal idempotents. Such an involution is termed canonical. As in the case that A is associative, corresponding to o are an involution * of A and a diagonal invertible matrix u = diag{y, ,..., m} such that U(X) = u-~(s*)~u, where t denotes the transpose. The diagonal entries yi lie in the nucleus N of -4, and iYZ yi for each i. In the derivation algebra Der H,(A, 0) is a subalgebra denoted by Der, A, since it is isomorphic to the algebra of derivations of A which commute with *. Also contained in Der I-I,(A, u) is the subalgebra ad,ll(,,,) of inner derivations by matrices which have entries in N, and which are skew relative to 0. The main result is that for 11 >J 4, Der H,(.4, u) = a4y,(N.0) + Der, A. More diversity can arise in the automorphism group of H,(il, o), but the common feature is the subgroup Aut,(M,(A)) consisting of automorphisms of &&(A) which commute with (T. If A is finite dimensional, this subgroup has finite index in Aut H,(A, a). Examples demonstrate that it need not be all of Aut H,(A, o), and depending on A, its index may be arbitrarily large.
Resistance and Escape From Antiangiogenesis Therapy: Clinical Implications and Future Strategies

Angiogenesis has long been considered an important target for cancer therapy. Initial efforts have primarily focused on targeting of endothelial and tumor-derived vascular endothelial growth factor signaling. As evidence emerges that angiogenesis has significant mechanistic complexity, therapeutic resistance and escape have become practical limitations to drug development. Here, we review the mechanisms by which dynamic changes occur in the tumor microenvironment in response to antiangiogenic therapy, leading to drug resistance. These mechanisms include direct selection of clonal cell populations with the capacity to rapidly upregulate alternative proangiogenic pathways, increased invasive capacity, and intrinsic resistance to hypoxia. The implications of normalization of vasculature with subsequently improved vascular function as a result of antiangiogenic therapy are explored, as are the implications of the ability to incorporate and co-opt otherwise normal vasculature. Finally, we consider the extent to which a better understanding of the biology of hypoxia and reoxygenation, as well as the depth and breadth of systems invested in angiogenesis, may offer putative biomarkers and novel therapeutic targets. Insights gained through this work may offer solutions for personalizing antiangiogenesis approaches and improving the outcome of patients with cancer.
The Costs of Reproductive Success in Male Rhesus Macaques (Macaca mulatta) on Cayo Santiago

Sexual selection acts to increase the success of males possessing advantageous traits in competition over females. In primates, interspecific variability in social and mating systems creates highly variable selective pressures on males, changing the relative strength of both intra- and intersexual selection, and the relative degree of direct vs. indirect male–male competition. Rhesus macaques are an interesting species for studying intrasexual selection and male–male competition, because they exhibit relatively low (for Papionini) body and canine size dimorphism, and exhibit large testes, suggesting reduced direct competition and strong indirect competition. We have undertaken several studies of male rhesus macaques on Cayo Santiago, from analyses of long-term life-history data to shorter term projects that combined noninvasive measures of physiological markers such as concentrations of urinary C-peptide of insulin and androgen and glucocorticoid (GC) concentrations, with measures of behavior and of sexually selected signals (male red facial coloration). We here review these studies, combining data from short-term studies with long-term mortality data to present an integrated picture of both the short- and long-term gross costs of male mating competition. We find that males exhibit many signs of the costs of indirect competition, such as energetic consequences of reduced feeding and high copulation rates. During periods of more direct contest, such as during dominance instability, males are also characterized by high androgen and GC concentrations among high-ranking individuals. Consistent with relatively weak direct male–male competition, male red skin coloration appears to be more related to female choice (intersexual selection) than the signaling of dominance status (intrasexual selection). Forty-five years of life-history data show that male mortality is higher during the mating than the birth season, a pattern we hypothesize to be linked to the costs associated with mating activity. We finish by discussing unresolved issues, such as the costs of sperm competition and the data that are needed to address them.
An Inexpensive Silver-Silver Chloride Reference Electrode

Simple, inexpensive, and rugged reference electrodes are essential for field applications. The objective of this study was to develop an inexpensive, field-worthy reference electrode. The electrode developed consists of a silver wire coated with AgCl held in a small glass tube filled with 4 M KCI gelled with agar. The glass tube assembly is fitted inside a larger polyvinyl chloride (PVC) tube filled with gelled (NH 4 ) 2 SO 4 solution and capped with a fritted soil-contacting membrane. The millivolt output compared well (r 2 = 0.999) with predicted values and values from commercial reference electrodes when paired with pH and nitrate-sensing electrodes. Comparisons of commercial and fabricated electrodes in two soils showed that the outputs were statistically the same, and that they were operational within a moisture range from saturation to 0.7 to 0.8 kg kg -1 , depending on the soil texture. The fabricated electrodes are low cost, rugged, and stable for months when kept wet.
Fashioning a work-based strategy for welfare reform based on international human rights doctrine.

The role of work in debates over welfare reform in the United States is analyzed. Five issues are identified and discussed under this heading, with special emphasis on the question of whether enough jobs exist to make it possible for all able-bodied welfare recipients to find paid employment in the regular labor market. It is argued that there are not enough jobs available—not even low-wage jobs—to make this a reasonable goal, and that neither conservatives nor liberals have faced up to the dilemma posed by this job shortage. International human rights doctrine concerning the availability of work at decent wages is cited in support of the proposition that the government should be held accountable for filling this job gap, not only for welfare recipients but for all other job-seekers as well. The costs of a hypothetical jobs program capable of achieving this goal are assessed, with the surprising result that it might actually save the public money. It is suggested that such a program could consitute an effective alternative to current welfare reform proposals.
The development of beta-lactamase as a highly versatile genetic reporter for eukaryotic cells

We describe in this report that TEM-1 beta-lactamase has several desirable characteristics as a genetic reporter. First, it has no endogenous counterpart in eukaryotic cells and therefore provides a background-free measure of gene expression. Second, because of the uniqueness of the substrate cleavage reaction, a wide variety of substrates which are efficiently cleaved can be synthesized for beta-lactamase. Third, since the assays involve no more than addition of substrate to media, it is possible to continuously monitor a culture without destruction of the cells. Fourth, the enzyme is extremely versatile in that it can be fused to other proteins and retain activity. To demonstrate the versatility of beta-lactamase, we created three forms of the enzyme including secreted, intracellular, and membrane-bound forms of the enzyme, each form having distinct advantages as a reporter system. We also showed that levels of secreted beta-lactamase were proportional to both the levels of transfected DNA, beta-lactamase mRNA, as well as activity of the chloramphenicol acetyl transferase gene controlled by the same promoter, validating the reliability of this reporter. beta-Lactamase thus represents a novel and highly versatile genetic reporter.
Integrating Physical and Chemical Characteristics of Lakes into the Glacially Influenced Landscape of the Northern Cascade Mountains, Washington State, USA.

/ A basic knowledge of the physical and chemical characteristics of lakes is needed by management to make informed decisions to protect water resources. In this study we investigated some of the physical and chemical characteristics of 58 lakes in alpine, subalpine, and forest vegetation zones in a natural area (North Cascades National Park Service Complex) between 1989 and 1993. The objectives of the study were to: (1) document the time of ice-out relative to lake elevation; (2) determine how a sharp climate gradient west and east of the hydrologic divide affected the time of ice-out for subalpine lakes; and (3) assess how lake water quality was associated with lake elevation, lake depth, and basin geology. As expected, lake ice-out times occurred earlier with decreasing elevation. East-slope subalpine lakes iced-out earlier than did west-slope subalpine lakes because the east slope of the study area was drier and warmer than the west slope. On average, the lakes were relatively cold, neutral in pH, and low in dissolved substances and concentrations of nitrogen and phosphorus. Although some shallow lakes (depth <10 m) exhibited the highest alkalinities, conductivities, and concentrations of phosphorus and nitrogen, most shallow lakes exhibited low values for these variables that were comparable to values observed in deep lakes. Geology did not play a major role in segregating the lakes based on water quality. Overall, lake temperature, pH, alkalinity, conductivity, and concentrations of total phosphorus and total Kjeldahl N increased with decreasing elevation. These changes in water quality with decreasing elevation in this temperate mountainous region corresponded with warmer air temperatures and increased vegetation biomass, soil depth and maturity, and dissolved substances and nutrients.KEY WORDS: Limnology; Mountain lakes; Water quality; North Cascades National Park Service Complex; National Park Servicehttp://link.springer-ny.com/link/service/journals/00267/bibs/24n2p219.html
Analysis of the Chandra x-ray observatory aspect camera PSF and its application to post-facto pointing aspect determination

For the last 20 months, the Chandra X-Ray Observatory (Weisskopf et. al. 2000) has been producing X-ray images of the universe in stunning detail. This is due in large part to the excellent post-facto pointing aspect determination for Chandra (Aldcroft et. al. 2000). This aspect determination performance is achieved using elliptical gaussian centroiding techniques. Application of point spread function (PSF) fitting using a true PSF model for the Aspect Camera Assembly (ACA) on Chandra could improve this performance. We have investigated the use of an ACA PSF model in the post-facto centroiding of stars and fiducial lights imaged by the ACA. We will present the methodologies explored for use in determining a model for the ACA PSF and discuss the results of a comparison of PSF fit centroiding and the current method of elliptical gaussian centroiding as they apply to post-facto aspect reconstruction. The first method of recovering the ACA PSF uses a raytrace model of the ACA to generate simulated stellar PSFs. In this method, the MACOS raytracing software package is used to describe each element of the Chandra aspect optical system. The second method investigated is the so called shift and add method whereby we build a high resolution image of the PSF by combining several thousand low resolution images of a single star collected by the ACA while tracking during normal science observations. The programmed dither of the spacecraft slowly sweeps the stellar image across the ACA focal plane, and the many slightly offset images are used to effectively increase the resolution of the resultant image of the star to a fraction of an ACA pixel. In each method, a library of PSF images is built at regularly gridded intervals across the ACA focal plane. This library is then used to interpolate a PSF at any desired position on the focal plane. We have used each method to reprocess the aspect solution of a set of archived Chandra observation and compare the results to one another and to the delivered post-facto aspect solution, currently derived using elliptical gaussian centroiding of ACA star images. Finally, we will present a summary of Chandra's aspect performance achieved to date, and discuss the effect of incorporating a PSF model into the post-facto aspect determination software.
Water Adduct Formation in Extracted Chelates

Abstract Water adducts of 1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, tris(4,7-diphenyl-1,10-phenanthroline) Fe(II) perchlorate, tris(4,7-diphenyl-1,10-phenanthroline) Ru(II) chloride, tris(1,10-phenanthroline) Fe(II) perchlorate, and bis(2,9-dimethyl-1,10-phenanthroline) Cu(I) perchlorate had 5.1 ± 0.9, 0 ± 1.3, 6.8 ± 0.6, 5.6 ± 1.5, 4.8 ± 0.7, 6.3 ± 0.6, and 6.5 ± 1.0 molecules of H2O, respectively, associated with them when they were extracted into nitromethane. All deviations are at the 95% C.I.
In-transit perishable product inspection

Abstract We determine the value of monitoring perishable freight in-transit for a single vehicle traveling from an origin to a destination. We develop a computationally practical approach for determining the optimal expected cost function and an optimal policy, based on an infinite horizon partially observed Markov decision process model. Structural properties of the optimal expected cost function and optimal policy are determined. These results can lend insight when deciding whether to acquire the capacity to monitor freight status in transit and what actions to take, based on the data from the in-transit monitoring, that optimally increase expected supply chain productivity.
RELIABILITY MODELING AND ANALYSIS OF COMPLEX HIERARCHICAL SYSTEMS

In this paper we consider the problem of reliability modeling and analysis of hierarchical computer-based systems (HS) with modular imperfect coverage (MIPC) and common-cause failures (CCF). The MIPC and CCF can cause vertical dependence that runs through different levels of the system as well as horizontal dependence that runs across components or modules on the same system level. The consideration of these dependencies poses unique challenges to existing HS reliability analysis methods. We propose an efficient decomposition and aggregation approach named EDA-HS to the reliability evaluation of complex hierarchical systems with both MIPC and CCF as one way to meet the above challenges in an efficient and elegant manner. Our approach is to decouple the effects of both MIPC and CCF from the combinatorics of the solution. The approach is represented in a dynamic fault tree by a proposed probabilistic functional dependency gate and a proposed CCF gate modeled after the existing FDEP gate. We present the basics and advantages of the EDA-HS approach by working through an analysis of an example HS subject to MIPC and CCF.
Differential effects of axotomy on the in vivo synthesis of the stress-inducible and constitutive 70-kDa heat-shock proteins in rat dorsal root ganglia

Abstract The purpose of this study was to the test the hypothesis that heat-shock protein expression is upregulated (or induced) in dorsal root ganglia (DRG) following axotomy. To test this hypothesis, DRG or sciatic nerve (SN) proteins were pulse-labelled in vivo with [35S]methionine and the metabolic synthesis of two major 70-kDa heat-shock proteins, the constitutive species (hsc70) and stress-inducible species (hsp68), were analyzed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and fluorography. Results showed that DRG hsp68 expression was absent (or barely detectable) under normal (sham-axotomy) conditions. However, following long-range axotomy (35 mm from DRG), there was a delayed (>12 h post-axotomy) and transient upregulation of DRG hsp68 metabolic synthesis. Control studies demonstrated that, although DRG hsp68 was upregulated, hsp68 was not induced in SN regions proximal to the crush site. In contrast to DRG hsp68 expression, there was abundant DRG hsc70 synthesis under normal conditions that did not significantly change following axotomy. These results suggest that a specific stress protein response is induced in DRG following axotomy. © 1997 Elsevier Science B.V. All rights reserved.
Seasonal and geothermal production variations in concentrations of He and CO2 in soil gases, Roosevelt Hot Springs Known Geothermal Resource Area, Utah, U.S.A.

Abstract To increase understanding of natural variations in soil gas concentrations, CO 2 , He, O 2 and N 2 were measured in soil gases collected regularly for several months from four sites at the Roosevelt Hot Springs Known Geothermal Resource Area, Utah. Soil temperature, air temperature, per cent relative humidity, barometric pressure and amounts of rain and snowfall were also monitored to determine the effect of meteorological parameters on concentrations of the measured gases. Considerable seasonal variation existed in concentrations of CO 2 and He. The parameters that most affected the soil-gas concentrations were soil and air temperatures. Moisture from rain and snow probably affected the soil-gas concentrations also. However, annual variations in meteorological parameters did not appear to affect measurements of anomalous concentrations in samples collected within a time period of a few days. Production from some of the geothermal wells probably affected the soil-gas concentrations.
Silicon diffusion characteristics of different surface-imaging resists

Abstract This paper describes a study of the silylation characteristics of different resists that are suitable forsingle-layer, surface-imaging patterning applications. In particular, the effect of different processparameters on the silicon diffusion in UCB's Plasmask®resist is discussed. The diffusion profileof silicon in the resist is decorated by a staining technique followed by SEM analysis. This allows for two-dimensional resolution of the diffusion profiles and the observation of other process attributes. Links are established among exposure, silylation and etch by observing silylated profiles.It is shown that the silylation profile characteristics are dominated by the resist image created duringexposure. Also, the effects of post-exposure bake and silylating agent temperature are presented.Diffusion profiles for MacDermid's PR1024 are also shown. 1. Introduction Surface imaging lithography relies on the imaging of the top resist layer in a stack of two or threelayers or the top surface of a single layer resist. Another characteristic of surface imaging is the useofplasmas to transfer the imaged layer into the underlying resist film or films. This paper deals withsingle-layer, surface imaging, resists. These resists were described by Taylor and Wolf [1] and oneof best known examples is the Plasmask® resist used in the DESIRE® System [2]. The advantagesand mechanisms ofthis process have been described elsewhere [3-5]. Figure 1 shows a basic schemefor this process, which involves exposing, baking, silylating, and plasma etching the resist. Thispaper deals with the silylation step; that is, the diffusion andreactionofa silylating agent in the resist.In particular, silylation from a gas phase with HMDS is discussed. Liquid silylating agents have beendiscussed [6], while the use of alternate gaseous silylating agents for other single layer processeshas also been described in the literature [7,8].The function of the silylation step is to form 0-Si bonds by displacing hydrogen from the OH pairsin the Novolak resin. In the case of the DESIRE® process, the silylation occurs in the exposed areawhere the photoactive compound has been destroyed and crosslinking cannot occur upon baking ofthe resist. Systems where the exposure induces the crosslinking ofthe resist, directly [8,9] or throughthe use of a crosslinking agent [10,1 1] have also been proposed. The depth, concentration anddiffusion profile of silicon after the silylation play a fundamental role in determining the quality ofthe mask formed during plasma exposure. Furthermore, the two-dimensional characteristics of thediffusion process have a direct impact on the silylation "contrast" of the resist.*
Effect of Certain Purines, and GO2 on Growth of Strain of Group A Hemolytic Streptococcus.∗

SummaryRapid, heavy growth and hemolysin production of the C203S strain of Group A hemolytic streptococcus have been obtained on a medium of essentially known composition. In addition to factors reported by previous workers, we have found that thiamin, nicotinic acid, adenine or related purines, and an unknown factor which may possibly be biotin are necessary for growth of this strain. The relation of carbon dioxide tension to the purine requirement has been studied.
General motors, Nazis, and the demise of urban rail transit

Abstract In 1974, the U.S. Senate Judiciary Committee's Subcommittee on Antitrust and Monopoly conducted hearings on concentration in America's ground transportation industries. A considerable portion of the testimony and supporting materials was related to a controversial report written by then Subcommittee staffer Bradford Snell. Snell cited General Motors as an example of a corporation that was powerful enough to adversely affect the national welfare by merely pursuing its own economic interests. The report stated that the G.M. owned Opel plant in Germany made a significant contribution to the Nazi war effort. Snell also accused the company of pursuing transportation policies that had a major effect on the demise of electric urban rail mass transit systems in the United States. General Motors voiced strong opposition to Snell's charges and presented considerable testimony in rebuttal. The following is a review of the controversy and its impact as registered in popular and academic literature.
Geophysics: A third way to rift continents

Rifting of continents is usually explained by one of two mechanisms based on effects that originate far from the zone of rifting. Laboratory experiments show that this geodynamic process can also be caused by local effects.
Origin of Deep Sea Cherts in the North Atlantic

SEISMIC profiling has revealed two strongly reflecting layers beneath the floor of the North Atlantic1. The shallower reflector is referred to as “horizon A” and the deeper as “horizon B”; JOIDES drill cores from the eastern and western North Atlantic and the Caribbean show that horizon A consists of a cherty material of Late–Early Eocene to Middle Eocene age2–4. Although the material of these layers is usually described as chert, the mineralogy is variable and the Eocene and Upper Cretaceous layers are composed chiefly of cristobalite rather than quartz, so they are not true cherts5.
Miskitu Labor and English Royalization at Augusta, Roatán Island, Honduras

In 1742, an outpost of English royalization was established on Roatan Island off the north coast of Honduras. The community, Augusta, housed a mix of English settlers and local indigenous Miskitu peoples. While the settlement was occupied for a brief span of only 7 years, the material record of the community provides insight into early English-Miskitu interactions during the process of English “royalization,” or the strategies deployed by monarchies to engender loyalty to a state. In this article, we discuss the concept of royalization from an agent-centered perspective and then describe the results of our four field seasons of archaeological investigations at Augusta, which have unearthed mixed deposits of English and Miskitu material culture. We argue that such deposits indicate that Miskitu labor and identity were entangled with English lifeways and lifestyles, and that these entanglements reveal some of the ways in which the process of royalization was adapted to the unique social and natural landscapes of the western Caribbean.
Estimates of Fog Element Length

Abstract The size of horizontal transmittance discontinuities must be known in order to optimize time and spatial representativeness of automated transmittance measurements. Results of computations using observed parameters are presented in a table of fog element sizes. Most fog elements embedded in a larger log volume ranged in size from about 50 to 100 ft in length. This information is useful to researchers interested in time and spatial representativeness of atmospheric transmittance data.
Beyond the Shade of the Oak Tree: The Recent Growth of Johannine Studies:

The recent growth within Johannine studies has developed as a result of several factors. First, the discovery of the Dead Sea Scrolls led to an appreciation of the Jewishness of John's origin. Second, new approaches to John's composition have emerged, followed by a larger set of inquiries as to the Johannine tradition's relation to parallel traditions. This has been accompanied by a fourth interest: the history of the Johannine situation. Fifth, new literary studies have posed new horizons for interpretation, and sixth, theories continue to abound on the identity of the Beloved Disciple. A seventh development involves new ways of conceiving John's theological features, leading to an eighth: reconsidering John's historical features and re-envisioning its historical contributions in new perspective.