cssi/SciSciGPT-SciSciNet huggingface dataset:
Highly plastic response in morphological and physiological traits to light, soil-N and moisture in the model invasive plant, Phalaris arundinacea

Abstract The ability of an introduced species to thrive is often influenced by its capacity to cope with disturbance and resource fluctuation, and one way to cope is by being phenotypically plastic. The biomass and resource allocation of the invasive plant species, Phalaris arundinacea (reed canarygrass), to contrasting levels of light, soil-N and moisture was evaluated. We predicted that P. arundinacea would show a highly plastic response in important growth and physiological traits to treatment conditions (presence of three-way interactions and large phenotypic plasticity index (PI) values) because of its ability to persist in variable environments. MANOVA tests showed significant three-way interactions for each of the three groups of plant traits (aboveground (AGB) and belowground biomass (BGB), shoot C/N and root C/N ratios, leaf chlorophyll and soluble protein), demonstrating the complex correlated response to the treatment effects by pairs of response variables. There were significant three-way interactions for seven of nine plant traits (univariate analyses), including AGB and BGB, AGB per tiller, shoot/root ratio, shoot C/N ratio, root C/N ratio and leaf chlorophyll content. Total plasticity values, which represented the greatest possible plasticity for each plant trait, were larger than any of the PI values for the main effects. Understanding which traits show plasticity, as well as the magnitude of response expressed in common invasive species is an important area of research because aspects of their aggressive behavior may be explained by how they grow and allocate resources under variable environmental conditions, which in turn can be important when seeking to make predictions about the probability and degree of invasion success with species-specific invasion models.
Defect pinning in monolayer films by highly controlled graphite defects : Molecule corrals

Domain boundaries in a self-assembled molecular film are immobilized or pinned for study with scanning tunneling microscopy using monolayer deep etch pits in the basal plane of graphite (molecule corrals). Molecule corrals are shown to provide a highly controllable method of generating substrate defects to study pinning in monolayer films. Diffusion of pinned boundaries is found to take place via discreet motions involving small groups of molecules. A model for grain boundary motion is developed and used to analyze two types ofboundaries : those separating molecular domains with identical structures and those separating domains with different structures. When the structures are different, a one-dimensional pressure is exerted on the boundary by the structure with the lower free energy, causing it to distort. By measuring the dependence of this distortion on the distance between pinning centers, we extract quantitative information about certain energetic properties of the film.
The effect of transport and boiling on Ag/Au ratios in hydrothermal solutions: a preliminary assessment and possible implications for the formation of epithermal precious-metal ore deposits

Abstract A thermodynamic model has been used to quantify the effects of transport and deposition on the gold and silver contents, Ag/Au ratios and ΣCO 2 /ΣH 2 S ratios in boiling hydrothermal solutions. Boiling is singled out because the majority of the precious-metal vein deposits studied exhibit some evidence of two-phase behavior. Several hundred model calculations were carried out for the following conditions: T = 150–300°C, Cl − = 0.1 and 1.0 m, pH = 4–6, ΣH 2 S = 0.1–10 −5 m, and ΣH 2 S/ΣSO 4 = 10−10 9 . The transport calculations indicate that low Ag/Au ratios ( − (0.1 m), moderate to high pH (⩾5) and ΣH 2 S (⩾10 −3 m), and high ΣH 2 S/ΣSO 4 ratios (>10 5 ). At these conditions, argentite is the most stable silver phase and gold is transported dominantly as Au(HS) 2 − . The AuCl 2 − complex dominates at high temperature (⩾250°C), high Cl − (1.0 m), low ΣH 2 S ( −3 m), low to moderate pH (⩽5), and low ΣH 2 S/ΣSO 4 ratios ( 5 ). These conditions favor high Ag/Au ratios in solution (> 1) and generally native silver as the most stable silver phase. The overall frequency distribution of the Ag/Au ratios in solution exhibits many similarities with patterns given for natural epithermal vein deposits. Collectively, these distributions display a pronounced mode between Ag/Au values of 10 and 100. The depth at which boiling commences becomes shallower with either decreasing temperature and/or CO 2 concentration for a constant salinity. Solutions with the highest initial gas concentrations will tend to deposit gold and silver over the greatest vertical distances, and produce deposits with lower ore grades. The model also predicts the presence of more intense zones of gold and silver enrichment near the top of the boiling interval which may be analogous to the very high-grade bonanza ores observed in many precious metal vein deposits. However, the low magnitudes of these enrichments during a single boiling event suggest that many volumes of a boiling fluid passing through a given volume of rock are required in order for ore grades in the mineralized boiling zone to reach levels typical of most epithermal deposits. During the boiling process, the Ag/au ratios remain relatively constant except near the top of the boiling interval where abrupt changes are observed. Significant increases in Ag/Au ratios are associated with systems that have moderate to high temperatures, high Cl − , low ΣH 2 S, low to moderate pH, and high ΣCO 2 /ΣH 2 S ratios. Conversely, a drop in the Ag/Au ratios near the top of the boiling zone accompanies systems with low temperature, low Cl − , moderate to high pH, high ΣH 2 S and low ΣCO 2 /ΣH 2 S ratios. The frequency distribution of the boiling Ag/Au ratios is very similar to both the transport histogram and the histograms for natural vein deposits. The Ag/Au mode of 10 to 100 is preserved, and the overall range of values is basically the same (10 −3 to 10 3 ).
Effect of inhibition of microsomal Ca2+-ATPase on cytoplasmic calcium and enzyme secretion in pancreatic acini

Abstract We used thapsigargin (TG), 2,5-di-tert-butyl-1,4-benzohydroquinone (BHQ) and cyclopiazonic acid (CPA), each of which inhibits microsomal Ca 2+ -ATPase, to evaluate the effects of this inhibition on cytoplasmic free calcium ([Ca 2+ ] i ) and secretagogue-stimulated enzyme secretion in rat pancreatic acini. Using single-cell microspectrofluorimetry of fura-2-loaded acini we found that all three agents caused a sustained increase in [Ca 2+ ] i by mobilizing calcium from inositol-(1,4,5)-trisphosphate-sensitive intracellular calcium stores and by promoting influx of extracellular calcium. Concentrations of all three agents that increased [Ca 2+ ] i potentiated the stimulation of enzyme secretion caused by secretagogues that activate adenylate cyclase but inhibited the stimulation of enzyme secretion caused by secretagogues that activate phospholipase C. With BHQ, potentiation of adenylate cyclase-mediated enzyme secretion occurred immediately whereas inhibition of phospholipase C-mediated enzyme secretion occurred only after several min of incubation. In addition, the effects of BHQ and CPA on both [Ca 2+ ] i and secretagogue-stimulated enzyme secretion were reversed completely by washing whereas the actions of TG could not be reversed by washing. Concentrations of BHQ in excess of those that caused maximal changes in [Ca 2+ ] i inhibited all modes of stimulated enzyme secretion by a mechanism that was apparently unrelated to changes in [Ca 2+ ] i . Finally, in contrast to the findings with TG and BHQ, CPA inhibited bombesin-stimulated enzyme secretion over a range of concentrations that was at least 10-fold lower than the range of concentrations over which CPA potentiated VIP-stimulated enzyme secretion.
Rejoinder to Lansing and de Vet

Since synchronous fallowing is the practice most discussedby Lansing and de Vet in their response to my critique ofLansing’s work, it’s the practice on which I will particularlyfocus in this necessarily brief rejoinder. Lansing and de Vetcorrectly state that I, like others, question how wellLansing’s analysis applies to conditions that existed beforethe Green Revolution that occurred after the 1960s.However, they then state, quite incorrectly, that I questionwhether rice-field pests were a problem at all before theGreen Revolution. In line with this misattribution, they thendevote a long paragraph to evidence of pests, especially rats,in earlier times. Actually I myself cite some such evidenceas well (Vayda 2009: 41, n.50). This is consistent with mystating not that the Green Revolution rice-intensificationprograms initiated rice-field pest problems but rather thatthey exacerbated them. Lansing and de Vet do not disputethat there was exacerbation. We agree also that a probablecause of it in many cases was the abandonment of synchro-nous fallowing as cropping with the new high-yielding ricevarieties became more frequent, although, in my mind, thiswas not the only or necessarily the most important cause ofexacerbation in all those cases (see, for example, the refer-ences cited in Vayda 2009: 41 on other factors in regard tobrown planthopper outbreaks).About what then do we disagree? Most significantly,about the claims of antiquity that are made by Lansing andhis associates for the evolution of the role of networks ofwater temples not only in the allocation of irrigation waterbut also in the control of rice-field pests over entire water-sheds. Such historical claims call for more than usingpresent-day observations for a computer simulation of whatmight have happened in the distant past. They call for moreand better historical evidence – evidence of what actuallydid happen– than Lansing et al. haveso far provided.Thatamain object of my critique of Lansing’s work was indeedthis failure of evidence would, I thought, have been madeclear by the fact that the critique was embedded in anextensive discussion of the problem of confirmation bias(Vayda 2009:29–43). However, in light of Lansing and deVet ’s not addressing that problem at all, I concede now that Iwas not being clear enough. Let me therefore repeat heresomething said –fairly emphatically, I thought – at the verybeginning of my discussion of the problem in my 2009book, namely, that perhaps the most common failure relatedto evidence in studies concerned with accounting for humanactions and/or environmental changes is the failure to judgethe evidence for one’s favored explanation in relation to thesupport that either the same or other evidence provides foralternative explanations (Vayda 2009: 29; cf. Vayda 2009:45 and, for discussions of the treatment of confirmation biasin my 2009 book, Walters et al. 2011).
Learning effective query transformations for enhanced requirements trace retrieval

In automated requirements traceability, significant improvements can be realized through incorporating user feedback into the trace retrieval process. However, existing feedback techniques are designed to improve results for individual queries. In this paper we present a novel technique designed to extend the benefits of user feedback across multiple trace queries. Our approach, named Trace Query Transformation (TQT), utilizes a novel form of Association Rule Mining to learn a set of query transformation rules which are used to improve the efficacy of future trace queries. We evaluate TQT using two different kinds of training sets. The first represents an initial set of queries directly modified by human analysts, while the second represents a set of queries generated by applying a query optimization process based on initial relevance feedback for trace links between a set of source and target documents. Both techniques are evaluated using requirements from theWorldVista Healthcare system, traced against certification requirements for the Commission for Healthcare Information Technology. Results show that the TQT technique returns significant improvements in the quality of generated trace links.
Effective field theory and electroweak radiative corrections

I discuss the S - and T -parameters introduced by Peskin and Takeuchi to characterize the “oblique” radiative corrections to the electroweak interactions. Following Golden and Randall, and Holdom and Terning, I re-interpret these parameters in an effective field theory language. I hope to draw attention to the fact that the effective field theory framework is not only simpler and more transparent, but it actually provides information about the corrections that goes beyond perturbation theory. I illustrate the power of this approach by showing that it automatically implements the “resummation” of the quadratic m t dependence in the oblique corrections conjectured by Consoli et al. I also show how to incorporate (or “resum”) all the logarithmic dependence on m H and m t . I also comment briefly on the non-oblique corrections. In particular, I identify all the sources of leading m t 2 -dependence in the low-energy theory Research supported in part by the National Science Foundation under grants PHY-8714654 and PHY82-17853, supplemented by funds from the National Aeronautics and Space Administration.
The effect of impurities on the spin-density-wave transition

Abstract The effect of impurities on the second order phase transition into the commensurate spin-density-wave state is considered for a two-band itinerant-electron antiferromagnet with imperfect nesting. The enhancement of electron-hole pairing by polarized magnetic impurities and the pair destruction effect of scattering by both magnetic and non-magnetic scatters is exhibited in a calculation of the dependence of the Neel temperature on magnetic impurity concentration and on the degree of imperfect nesting. The commensurate SDW is shown to be stabilized by magnetic impurities.
Dynamic Behavior of TCR Microclusters on a Live Cell Investigated by a Gold Nanoparticle Array

T cell receptor (TCR) microclusters play an important role as they are the sites of regulation of early T cell signaling. TCR microclusters are, however, difficult to study because their size is too small for conventional fluorescence microscopy and too large for physicochemical methods that depend on proximity effect such as FRET. Despite the recent advancement in superresolution microscopies, their use is still limited to fixed cells or slow processes in the cell. We developed a new platform for probing and manipulating TCR microclusters on a live cell by mechanical means. A two-dimensional array of gold nanoparticles is embedded on the glass substrate. A supported membrane, which acts as a surrogate cell membrane that has laterally fluid ligand molecules for cells, was deposited on a glass substrate with a regular array of gold nanoparticles. The supported membrane interacted with T cells and the lateral movement of TCR microclusters on the T cell surface was effectively altered by the gold nanoparticles. This platform offers many opportunities for studying this poorly understood size regime of protein assemblies on a live cell.
Total synthesis and cloning of a gene coding for the ribonuclease S protein

A gene for ribonuclease S protein, has been chemically synthesized and cloned. The gene is designed to have 25 specific restriction endonuclease sites spaced at short intervals, permitting its structure to be rapidly modified. This flexibility facilitates tests of hypotheses relating the primary structure of the enzyme to its physical and catalytic behavior.
Children with fetal alcohol spectrum disorders: a descriptive profile of adaptive function.

Background. Children with fetal alcohol spectrum disorders (FASD) demonstrate neurobehavioral impairments that affect function and participation. Adaptive behavior deficits have been documented; ho...
A computational study of some isomerization equilibria and their possible relation to vinyl chloride carcinogenicity

There is considerable evidence indicating that the primary in vivo DNA alkylation product of vinyl chloride, believed to be responsible for its carcinogenicity, is the 7-N-(2-oxoethyl) derivative of guanine. Using a representative keto-enol system, we have studied computationally two possible equilibria involving this adduct. The first is between the 2-oxoethyl derivatives of the keto and enol forms of the representative system, whereas the second is between the 2-oxoethyl derivative of the keto form and the corresponding hemiacetal. In the case of the analogous guanine derivatives, such equilibria could lead to disruption of the hydrogen bonding between guanine and cytosine in DNA and could cause miscoding and replicational and transcriptional errors. An ab initio self-consistent field molecular orbital study has been carried out using the GAUSSIAN 82 system of programs. Optimized structures and energies have been calculated at the 2-21G level for the representative keto-enol system and its 2-oxoethyl and hemiacetal forms. The formation of the 2-oxoethyl adduct was found to have no significant effect upon this keto-enol equilibrium, which strongly favors the keto form. Our calculations further show hemiacetal formation to be an unlikely possibility for this system. On the basis of these results and recent data on guanine tautomers, we speculate about the analogous equilibria involving the guanine derivatives.
A quantitative study of preporcelain soldered connector strength with palladium-based porcelain bonding alloys.

I n the making of multiple unit fixed prostheses, individual segments must be joined at some stage, either by casting the metal framework as one piece or by soldering the individual units. The soldering method has the advantage of permitting each individual retainer to be fitted to the abutment instead of fitting the entire prosthesis to multiple abutment teeth. To avoid exposing glazed porcelain to soldering investment and the soldering procedure, preporcelain soldering is preferred by some to postporcelain soldering. Recently, new compositions of dental porcelain bonding alloys were introduced. They are palladium-based, noble, and are comparatively low in cost. Their nobility is derived from the 75% to 85% palladium in their composition, with the addition of gold or platinum that yields a total of 80% to 90% noble metals. Smaller amounts of cobalt, gallium, indium, copper, and silicon are added to improve oxide formation for porcelain bonding, regulate the melting range, to improve strength, and for castability. The purpose of this study is to quantitatively evaluate the preporcelain soldered connector tensile strength of noble palladium-based alloys with conventional soldering procedures. Many investigations have evaluated soldered connectors. In 1975 Stade et al.’ found that the method of soldering was more significant to connector strength than gap width. Other investigators reported that nonnoble alloys cannot be consistently and adequately soldered.2-4 In an extensive two-part study Staffanou et a1.5 concluded that various combinations of precious, semiprecious, and base metal alloys could be successfully soldered. Barnard et a1.6 observed that a large excess of flux was necessary for soldering base metal alloy. Rasmussen et al.’ reported that preceramic soldered connectors with a high noble alloy content decreased in strength with increasing gap width. However, no investigation has focused on the soldered connectors of noble palladiumbased porcelain bonding alloys.
Necessary and sufficient conditions for a stochastic approximation methos

On etudie les conditions necessaires et suffisantes de convergence d'une methode d'approximation stochastique de type Robbins-Monro
Ovarian complete hydatidiform mole: case study with molecular analysis and review of the literature

Ectopic complete molar pregnancy in the ovary is an exceptionally rare event. Here we present a case of ovarian complete hydatidiform mole in a 20-year-old gravida 2 para 1 woman. At presentation, the patient underwent excision of a hemorrhagic left ovarian cyst, with routine sections demonstrating a hemorrhagic corpus luteum with a single microscopic focus of detached atypical trophoblast, without chorionic villi. Subsequent left salpingo-oophorectomy for persistently elevated human chorionic gonadotropin led to a final diagnosis of complete hydatidiform mole arising in the ovary. The fallopian tube was unremarkable. Zygosity was determined using short tandem repeat analysis, confirming the diagnosis of monospermic complete mole. In the clinical setting of a markedly elevated human chorionic gonadotropin level and an ovarian mass, histopathologic examination is critical in distinguishing ectopic pregnancy from choriocarcinoma. Short tandem repeat analysis can be a useful adjunct to histologic diagnosis in challenging cases.
Methane calculations using the multiple-scattering technique with x α exchange†

Calculations for methane using the multiple-scattering Xα (MSXα) method are reported. The total energy, symmetric (“breathing” mode) potential energy curve, symmetric harmonic force constant, and ionization energies are given. Comparison reveals that all of these quantities compare well with typical Hartree-Fock (HF) calculations with the ionization energies obtained and long-range part of the potential energy curve being superior to HF.
A revealed preference test of rationing a Monte Carlo analysis

Abstract This paper develops and evaluates a rationing linear programming procedure that uses an “efficiency index” to allow for violations of revealed preference to be attributed to “almost” optimal choices. The procedure detects rationing using U.K. data. Various Monte Carlo simulations are performed to evaluate the ability of the procedure to differentiate between violations of revealed preferences caused by random error and those caused by rationing.
Permeable Cell Systems as Models for Studying Disruption, by Site-Specific Synthetic Peptides, of Receptor–G Protein–Effector Coupling

Abstract Synthetic peptides corresponding to the carboxyl terminal of Gsα have been demonstrated to block activation of Gsα by the β-adrenergic receptor and the subsequent activation of adenylyl cyclase. These same peptides appear to mimic Gsα in promoting high-affinity agonist binding to that receptor. Curiously, attempts to achieve these responses in membranes have met with limited success. Thus, it appears that the cellular milieu surrounding the plasma membrane is best left intact. To disrupt the coupling between receptors and Gsα, a mechanism for making cells permeable has been devised to allow an effective examination of both adenylyl cyclase and radioligand binding in an environment that resembles an intact cell. Described herein is a method for making cells permeable in order utilize synthetic peptides to probe structure–function relationships of G protein α subunits in their ability to interface with both receptors and effector molecules. Specific methods for assaying adenylyl cyclase and the number and affinity of β-adrenergic receptors are described.
Presence of CD4 and CD8 determinants on CD4−CD8− murine thymocytes: passive acquisition of CD8 accessory molecules

In the present study we have examined the possibility that CD4 and CD8 accessory molecules can be passively acquired by thymocytes. We initially observed that most thymocytes contained within the CD4-CD8- subset actually possess low levels of CD4 and CD8 on their cell surface. However, the detection of CD4 and CD8 on CD4-CD8- cells was dependent on the presence of other CD4+/CD8+ thymocytes which were actively synthesizing CD4 and CD8. These initial findings suggested that the appearance of CD4/CD8 on "double-negative" thymocytes was due to the passive acquisition of these accessory molecules from CD4+/CD8+ cells present within the thymus. To investigate this possibility directly, we made both in vivo and in vitro mixes of thymocytes possessing different alleles of CD8 (Ly-2.1 and Ly-2.2). Under these experimental conditions, we detected Ly-2.2 on the surface of thymocytes that were genetically Ly-2.1+ and incapable of synthesizing Ly-2.2. These data indicate that thymocytes can express cell surface CD8 molecules which they have not produced but have acquired from other cells in their environment. Thus, the present study indicates that low-level surface expression of cell surface CD4/CD8 differentiation molecules does not necessarily identify distinct thymocyte subpopulations.
All-trans-retinoic acid decreases vein graft intimal hyperplasia and matrix metalloproteinase activity in vivo.

Background. Development of vein graft intimal hyperplasia has been associated with increased activity of matrix metalloproteinases (MMPs). All-trans-retinoic acid (atRA) decreases expression and activity of MMPs in tissue culture and has decreased intimal hyperplasia following arterial balloon catheter injury. We examined the effect of oral administration of atRA on intimal hyperplasia and MMP expression in an animal model of vein bypass grafting. Materials and methods. Interposition jugular vein bypass grafts were placed in the carotid artery of New Zealand white rabbits. Animals received either atRA (10 mg/kg/day) or vehicle (corn oil) for a period of 2 weeks. Retinoic acid serum levels were determined by HPLC. Intimal and medial areas were measured using morphometric analysis of perfusion-fixed vein graft specimens, and intimal thickness was calculated using circumferential measurements. Expression of MMP-2, MMP-9, and TIMP-1 in vein grafts and unoperated control veins was determined using Northern analysis, and proteolytic activity was determined using substrate gel zymography. Results. Animals treated with atRA had significantly elevated serum levels of this compound and its metabolites. A decrease in intimal to medial ratio was noted after 28 days in vein grafts from treated animals (0.63 vs 0.88, P < 0.01), and a decrease in calculated intimal thickness was noted at 7 and 28 days. Expression of MMP-2 was decreased in treated animals 7 days following surgery, and expression of both MMP-2 and MMP-9 was decreased at 28 days. A decrease in proteolytic activity was noted on zymography at 68 kDa, 7 and 28 days following surgery in vein grafts from animals treated with atRA, corresponding with a decrease in the active form of MMP-2. Increased expression of TIMP-1 was noted in vein grafts from both the treated and the control groups, 7 and 28 days following graft placement. Conclusions. Oral administration of all-trans-retinoic acid resulted in decreased intimal hyperplasia in an animal model of vein bypass grafting. This was associated with decreased expression and activity of MMP-2 in treated animals.
Effects of colloids, flocculation, particle size, and organic matter on the adsorption of hexachlorobenzene to sediments

Understanding and quantifying the dynamics of the sorption and partitioning of contaminants to sediments is essential in understanding and predicting the transport and fate of hydrophobic contaminants in aquatic environments. In previous work, the time-dependent effects of hexachlorobenzene (HCB) dissolution, the flocculation of colloidal matter from the water, and the flocculation of the suspended particles on the adsorption and partitioning of HCB to natural sediments from the Detroit River were investigated by means of batch-mixing experiments. These experiments were conducted for long times (up to 6 months) to be certain that a steady state had been reached. In the present study, this investigation has been extended, and the effects of colloids from the sediments and from the water, the flocculation of these colloids and of the sediments, particle size, and organic matter on HCB adsorption and partitioning have been quantified. It is shown that the measured steady-state partition coefficients depend on the amount of colloids from the water and from the sediments and on the amount of organic matter in the sediments. The adsorption rates depend on these quantities as well as the flocculation of the colloids, the flocculation of the sediments, and the particle size.
Contingency Hypotheses in Strategic Management Research: Use, Disuse, or Misuse?

The answer to many strategic management research questions is often summarized as “It depends.” Faced with the marginal results of many main effect hypothesis tests of one variable on another variable, strategy researchers began developing contingency hypotheses that explored more nuanced relationships involving multiple variables. Herein, the authors examine the development of contingency thinking in strategic management via a review of all empirical articles published in Strategic Management Journal from its inception in 1980 through 2009. Using Venkatraman’s framework, they identify all contingency studies within this sample. Their analysis reveals that, while contingency hypotheses are becoming more common, there is less diversity in the way the effects are tested. Additionally, while the framing of contingency hypotheses has become more sophisticated over time, there remain many opportunities for methodological improvements. Based on this content analysis, the authors offer both theoretical and metho...
Endothelial dysfunction in African-Americans

The journey of atherosclerosis begins with endothelial dysfunction and culminates into its most fearful destination producing ischemia, myocardial infarction and death. The excess cardiovascular disease morbidity and mortality in African-Americans is one of the major public health problems. In this review, we discuss vascular endothelial dysfunction as a key element for excess cardiovascular disease burden in this target population. It can be logical window of future atherosclerotic outcomes, and further efforts should be made to detect it at the earliest in African American individuals even if they are appearing healthy as the therapeutic interventions if instituted early, might prevent the subsequent cardiac events.
Behavior compensation reduces loads in the cervical spine measured with a force-sensing implant

Low back pain is growing health concern affecting 31 million Americans at any given time. Many of the risk factors for low back pain are mechanical in nature. Characterizing the axial loads, muscle recruitment, and behavior compensation during everyday motion an important step in minimizng the mechanical risk factors. The purpose of this study was to use an interbody implant to analyze the intradiscal forces in an in vivo model during everyday activities and to monitor the effect of behavior compensation on the resulting loads.
Texas Manufacturers of Sewn Products: A Typology of Strategic Posture by Risk Level:

The study was conducted to determine how strategic posture of sewn-products manufacturers influences their use of newer technologies important to company competitiveness. The objectives were to develop a typology of Texas sewn-products manufacturers according to strategic posture by risk level, and to develop group profiles by company demographics and production characteristics. Questionnaires were mailed to Texas manufacturers of sewn products resulting in 123 usable surveys. Cluster analysis was used to segment the manufacturers according to their level of risk. MANOVA and discriminant analysis were used to distinguish among the groups. Profiles of groups were developed using company demographics and production characteristics (production system, plant layout, sewing machine technology, computer usage, and employee training and compensation). The High Risk group accepted and integrated more technology than the other three groups, indicating the need for proactiveness to compete in business.
Sphenoclea zeylanica (Sphenocleaceae) in North America—Dispersal, Ecology, and Morphology

ABSTRACT Sphenoclea zeylanicais described and its phenology, habitat, and distribution documented in North America, based upon data from voucher specimens and original field observations. The species, an exotic native to Asia, has been in the United States since the mid-1800s, with the earliest records from Louisiana where it was most likely introduced as a contaminant of rice seed. Its distribution and spread are linked strongly with cultivation of rice, and we document its dispersal in the United States over the past 150 years with the postbellum expansion of rice agriculture in the Mississippi River Valley. Photographs and scanning electron micrographs illustrate structural details of inflorescence, flower, fruit, and seed.
Image retrieval based on intrinsic spectral histogram representation

The spectral histogram features are not invariant to images' scale transformation. We investigate in the technique of scale-invariant feature extraction. An approach is proposed to get the characteristic scales based on the reliable keypoints which are detected as local extrema in combination of normalized derivatives. Making use of characteristic scale of image content, which reflects characteristic length of a corresponding image structure, we are able to contribute in eliminating the effect of image transformation. In our content based image retrieval process, images are firstly resized by the characteristic scale and then represented based on the statistics of their spectral components and a linear dimension reduction technique optimizing class differentiation with respect to cross-correlation metrics of spectral histograms. Our retrieval consists of a preliminary classification step to index images in dataset and a following step of class by class retrieval. Experiments are performed on the Corel database and the outcome is compared with those of some existing work.
Other-Sex Friendship Involvement among Delinquent Adolescent Females:

Ninety-two delinquent and nondelinquent African American and Hispanic adolescent females (ages 13 to 17) from Los Angeles County were interviewed to determine the likelihood of male friendship selection. Using both qualitative and quantitative measures, the group's demographic backgrounds, friendship selection, and quality were compared. Additionally, delinquent girls completed measures examining their self-perceptions and feelings of loneliness. Results indicate that delinquent girls are significantly more likely than nondelinquent girls to identify males as their closest friends. Age of friend, perceived advantages of the friendship, and involvement in delinquent and similar activities are related to male friendship selection. The results also reveal that delinquent girls with male friends do not differ from the female-friend groups on quantitative measures of friendship quality. Finally, among the delinquent population only, no differences between friendship groups exist for feelings of loneliness, competence, and self-worth.
Minimum effective scale in export promotion

Nonprice promotion has long been used by small firms or organizations to increase agricultural exports. Some believe that export promotion in these cases is often unsuccessful as the promoter is unable to achieve the “critical mass” of awareness that is required for success. The objective of this article is to develop a theoretical explanation for the likely existence of minimum expenditure thresholds and to estimate their size using an econometric model of the optimal supply of advertising. An empirical example of apple promotion from Washington state (USA) finds minimum effective scale levels for four key promotion activities among several Latin American countries.[EconLit citations: C34, M37, Q17]. © 2002 Wiley Periodicals, Inc.
DESIGN AND EVALUATION OF A 3-D OPTIMAL ASCENT GUIDANCE ALGORITHM

This paper considers the problem of optimal threedimensional guidance of a launch vehicle through the atmosphere while satisfying a set of operational constraints, and satisfying a set of tangency conditions at main engine cut-off. A hybrid analytic/numerical approach is applied to the solution of this problem. The resulting guidance algorithm makes maximum utilization of the analytically tractable portions of the solution to construct a set of interpolating functions. These functions are then used in a numerical treatment of the total problem based on the method of collocation. A numerical study is performed using a single stage vehicle model. The results indicate that the guidance algorithm converges reliably and accurately, and that the execution time required for a single guidance update is well within the realm of real time implementation. Nomenclature
Exploitation of spatiotemporal information and geometric optimization of signal/noise performance using arrays of carbon black-polymer composite vapor detectors

We have investigated various aspects of the geometric and spatiotemporal response properties of an array of sorption-based vapor detectors. The detectors of specific interest are composites of insulating organic polymers filled with electrical conductors, wherein the detector film provides a reversible dc electrical resistance change upon the sorption of an analyte vapor. An analytical expression derived for the signal/noise performance as a function of detector volume implies that there is an optimum detector film volume which will produce the highest signal/noise ratio for a given carbon black-polymer composite when exposed to a fixed volume of sampled analyte. This prediction has been verified experimentally by exploring the response behavior of detectors having a variety of different geometric form factors. We also demonstrate that useful information can be obtained from the spatiotemporal response profile of an analyte moving at a controlled flow velocity across an array of chemically identical, but spatially nonequivalent, detectors. Finally, we demonstrate the use of these design principles, incorporated with an analysis of the changes in detector signals in response to variations in analyte flow rate, to obtain useful information on the composition of analytes and analyte mixtures.
Approximate Star-Shaped Decomposition of Point Set Data

Simplification or decomposition is a common strategy to handle large geometric models, which otherwise require excessive computation to process. Star-shaped decomposition partitions a model into a set of star-shaped components. A model is star shaped if and only if there exists at least one point w hich can see all the points of the model. Due to this interesting property, decomposing a model into star-shaped co mponents can be used for computing camera locations to guard a given environment (the art-gallery problem) , skeleton extraction, point data compression, as well as motion planning. In this paper, we propose a simple method to partition (or cluster) point set data (PSD) into “approximately star-shaped” components. Our method can b e applied to both 2D and 3D PSD and can be naturally extended to higher dimensional spaces. Our method doe s not require or compute any connectivity information of the input points. The proposed method only requires the pos ition and the outward normals of points. Our experimental results show that the size of the final decomposition is clo se to optimal.
A new aperture plane method of measuring antenna surface errors

A scheme for measuring surface errors of reflector antennas is proposed in which the phase of the signals from small areas of the wavefront are compared one by one to the phase of the signal from the rest of the wavefront. The comparison is accomplished by periodically changing the phase of the signal from each small area by /spl plusmn/90/spl deg/. For convenience and economy, the measurement can be made in an aperture plane of an antenna feed system, and can be done in real time with the antenna pointing steadily at the source being observed. Estimates are made of the signal power required for the measurement, and three means of modulating the phase are suggested, one of which allows the surface error of the antenna to be corrected as well as measured. >
Surface normal overlap: a computer-aided detection algorithm with application to colonic polyps and lung nodules in helical CT

We developed a novel computer-aided detection (CAD) algorithm called the surface normal overlap method that we applied to colonic polyp detection and lung nodule detection in helical computed tomography (CT) images. We demonstrate some of the theoretical aspects of this algorithm using a statistical shape model. The algorithm was then optimized on simulated CT data and evaluated using a per-lesion cross-validation on 8 CT colonography datasets and on 8 chest CT datasets. It is able to achieve 100% sensitivity for colonic polyps 10 mm and larger at 7.0 false positives (FPs)/dataset and 90% sensitivity for solid lung nodules 6 mm and larger at 5.6 FP/dataset.
Strain, stress and stretch of peripheral nerve Rabbit experiments in vitro and in vivo

Mechanical stretching is known to cause morphologic and functional changes in peripheral nerve. The points at which these changes occur, however, are not clearly defined and reported data are conflicting. The studies presented in this paper provide a basic understanding of the biomechanical properties, stretch-injury patterns, and changes of conduction properties of peripheral nerves due to stretching. Our studies showed that peripheral nerves exhibited nonlinear stress-strain characteristics when placed under tension. Initially, under tension, the nerve had a low modulus that increased gradually with increasing strain until reaching a maximal value. When the nerve failed under tension, the perineurium inside the nerve ruptured, but the exterior of the nerve remained intact. Our results also show that a peripheral nerve in situ was under significant strain, but minimal in situ stress (less than 0.05 MPa). The in situ strain might vary with limb position, but did not appear to exceed the limit beyond which...
PERSPECTIVE: User toolkits for innovation

Manufacturers must accurately understand user needs in order to develop successful products–but the task is becoming steadily more difficult as user needs change more rapidly, and as firms increasingly seek to serve “markets of one.” User toolkits for innovation allow manufacturers to actually abandon their attempts to understand user needs in detail in favor of transferring need-related aspects of product and service development to users along with an appropriate toolkit. User toolkits for innovation are specific to given product or service type and to a specified production system. Within those general constraints, they give users real freedom to innovate, allowing them to develop their custom product via iterative trial-and-error. That is, users can create a preliminary design, simulate or prototype it, evaluate its functioning in their own use environment, and then iteratively improve it until satisfied. As the concept is evolving, toolkits guide the user to insure that the completed design can be produced on the intended production system without change. Pioneering applications in areas ranging from the development of custom integrated circuits to the development of custom foods show that user toolkits for innovation can be much more effective than traditional, manufacturer-based development methods.
Response to Hepatitis B Vaccine in HIV-1–Positive Subjects Who Test Positive for Isolated Antibody to Hepatitis B Core Antigen: Implications for Hepatitis B Vaccine Strategies

Background. Whether human immunodeficiency virus type 1 (HIV-1)-positive subjects who test positive for isolated antibody to hepatitis B core antigen (anti-HBc) should be vaccinated with hepatitis B vaccine is not certain. Development of an anamnestic response after vaccination would suggest previous hepatitis B virus (HBV) infection, in which case vaccination is not necessary. Methods. Sixty-nine HIV-1-positive subjects who tested negative for hepatitis B surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) received vaccination with standard hepatitis B vaccine. Twenty-nine subjects (42%) tested positive for anti-HBc, and 40 (58%) tested negative for anti-HBc. An anamnestic response was defined as an anti-HBs titer of ≥10 IU/L within 4 weeks of the first vaccination. Results. The overall anamnestic response rate was 16% and was not significantly different between subjects who tested positive for anti-HBc (24%) and those who tested negative for anti-HBc (10%) before vaccination (P =.18). Approximately 50% of subjects who tested positive for anti-HBc also tested positive for antibody to hepatitis Be antigen (anti-HBe). The anamnestic response rate was higher in subjects who tested positive for both anti-HBc and anti-HBe (43%) than in subjects who tested positive for anti-HBc but negative for anti-HBe (7%) (P =.035). After a complete series of vaccinations, HIV-1/hepatitis C virus (HCV)-coinfected subjects were less likely to achieve high anti-HBs titers than were subjects infected with HIV-1 alone. Conclusions. After hepatitis B vaccination, the anamnestic response rate in HIV-1-positive subjects who tested positive for isolated anti-HBc but negative for anti-HBe was low and was comparable to that in subjects who tested negative for anti-HBc. This finding suggests that testing for anti-HBc alone may not be a reliable assessment of protection from HBV infection. HIV-1/HCV coinfection may be associated with impaired responses to hepatitis B vaccine, and evaluation of strategies to improve immunogenicity of the vaccine in such individuals is warranted.
Conservatism and Aggregation: The Effect on Cost of Equity Capital and the Efficiency of Debt Contracts

This paper studies the joint effect of conservatism and aggregation on the cost of equity capital and the efficiency of debt contracts. In the model, a firm's two assets are valued at either the lower-of-cost-or-market or fair value and the accounting report aggregates the value of the two assets. While the process of aggregation leads inevitably to a loss of information, what information is lost depends on the accounting regime. In the conservative regime, gains are ignored while in the fair value regime gains are off-set against losses.The paper studies the joint effect of conservatism and aggregation in two settings. First, it considers an all-equity firm and compares the valuation of equity when investors observe an accounting report under either the conservative or a fair-value regime. The model predicts that cost of equity capital is lower in the conservative regime than in the fair value regime if the firm's production function exhibits sufficiently decreasing marginal returns. Second, the paper takes a contractual perspective and considers the efficiency of debt contracts when debt covenants must be written in terms of the accounting report. The paper shows the maximum capital that can be raised by a debt contract which implements efficient post-contractual decisions is higher in the conservative than in the fair value regime.