cssi/SciSciGPT-SciSciNet huggingface dataset:
Zero temperature chiral phase transition in SU(N) gauge theories

Recently Appelquist, Terning, and Wijewardhana investigated the zero-temperature chiral phase transition in SU(N) gauge theory as the number of fermions N{sub f} is varied. They argued that there is a critical number of fermions N{sub f}{sup c}, above which there is no chiral symmetry breaking and below which chiral symmetry breaking and confinement set in. They further argued that the transition is not second order even though the order parameter for chiral symmetry breaking vanishes continuously as N{sub f} approaches N{sub f}{sup c} on the broken side. In this note I propose a simple physical picture for the spectrum of states as N{sub f} approaches N{sub f}{sup c} from below ( i.e., on the broken side) and argue that this picture predicts very different and {ital nonuniversal} behavior than is the case in an ordinary second order phase transition. In this way the transition can be {ital continuous} without behaving conventionally. I further argue that this feature results from the (presumed) existence of an infrared Banks-Zaks fixed point of the gauge coupling in the neighborhood of the chiral transition and, therefore, depends on the long-distance nature of the non-Abelian gauge force. {copyright} {ital 1997} {ital The American Physical Society}
The Na, K-ATPase Beta1 and Beta2 Subunits Associate with Different Quality Control Pathways in the ER

The catalytic Na,K-ATPase α-subunit is not able to exit the ER or catalyze ion transport unless assembled with the β-subunit. However, requirements for the ER exit of the Na,K-ATPase β-subunit that plays an additional, ion-transport-independent, role in intercellular adhesion are not clear. The Na,K-ATPase β1- or β2-subunits and their N-glycosylation-deficient mutants were expressed in renal MDCK cells. Confocal microscopy, immunohistochemistry, and immunoprecipitation were employed to evaluate the role of N-glycans of the β-subunit isoforms in the quality control of the Na,K-ATPase in the ER. Mutagenic removal of as few as two of the eight N-glycosylation sites from the β2-subunit precludes its assembly with the α1 subunit and results in full retention of the unassembled β2-subunit in the ER. However, removal of all three N-glycosylation sites from the β1-subunit only slightly affects its assembly with the α1-subunit and trafficking to the plasma membrane. The β2-subunit binds 4-5-fold more efficiently to the ER lectin chaperone, calnexin, and 2-3-fold less efficiently to the non-lectin ER chaperone, BiP, than the β1-subunit. These results indicate that folding of the β2- and β1-subunits is mediated by lectin and non-lectin chaperones, respectively, consistent with the essential role of N-glycosylation for folding and trafficking of the β2 but not of the β1-subunit. Disruption of the α1-β association by mutations in defined α1-interacting regions of either β1- or β2-subunits results in the ER retention of unassembled mutants, indicating that α-β assembly is essential for the ER export of either β-subunit isoform. In conclusion, the ER quality control system ensures that only properly folded β-subunits assemble with the α-subunits and only assembled α-β complexes are exported to the Golgi and delivered to the plasma membrane.Supported by NIH, DK077149 and DK58333.
Characterization of a T-cell determinant defined by a monoclonal antibody (TH5.2) which is involved in the interleukin-2-producing and proliferative capabilities of T cells

Abstract Utilizing an OKT-4-positive human T-cell lymphoma cell line as immunogen, we have produced a monoclonal antibody (MAb), designated TH5.2, which is capable of augmenting the interleukin-2 (IL-2) production and proliferation of antigen-activated T cells. TH5.2 MAb by itself is not mitogenic for T cells; the enhanced IL-2 production and proliferation requires costimulation with either antigen or mitogen. TH.2 MAb recognizes all peripheral blood T cells at varying intensities, but does not react with monocytes. Using dual-color fluorescence analysis, it was determined that TH5.2 MAb reacts at a higher intensity on Leu-3a-positive T cells compared to Leu-2a-positive cells. Sorting T cells on the basis of fluorescent intensity with TH5.2 MAb demonstrated that the T cells reacting at high TH5.2 intensity were able to respond to mitogen at a higher rate (5–10×), as well as produce higher concentrations of IL-2 in response to mitogen as compared to the low IL-2 intensity cells. Cytotoxically treating peripheral blood mononuclear cells (PBMC) with TH5.2 MAb plus complement, which resulted in an approximate 8% decrease in the total population, significantly reduced the ability of the cells to proliferate to both mitogen and antigen. Addition of recombinant IL-2 to the cultures was able to restore the proliferative capability of the cells. In further analyzing the ability of TH5.2 MAb to augment the proliferative capability of PBMC to antigen and mitogen stimulation in vitro , it was determined that TH5.2 MAb was capable of acting synergistically with antigen or mitogen in increasing the Il-2-producing capability of T cells. Taken together the data suggest that the TH5.2 determinant is involved in the proliferative capability of T cells and is functioning at the level of IL-2 synthesis and/or secretion.
Fluctuations in non-linear photon-matter interactions that lead to paradoxical phenomena in optical communications

Non-linear phenomena impact the quality of optical transmission along the dielectric fiber. The theoretical analysis of non-linear interaction of light and matter assumes that certain parameters are either positive or within a bounded range. However, these assumptions although pragmatic may overshadow other possible outcomes that lead to paradoxical consequences of interest. In this paper, we review the theory of optical propagation and particularly the non-linear interaction between adjacent optical channels that propagate in a dielectric medium such as fiber, and we challenge traditional mathematical assumptions. We describe under what conditions the mathematical relation of the dielectric constant e(w)is expressed in terms of tuning or detuning between two oscillators, and under what conditions it is e(w)>1, e(w)<1, and also under what conditions e(w) becomes negative. The latter is of particular importance because if such conditions are achievable, matter has negative dielectric constant, the refractive index is purely imaginary, the group velocity meaningless, and a new chapter in photonic technology opens.
Solar Heating of Poultry Houses 1. An Analysis of Energy Use for Brooding Broiler Chickens

Abstract A comprehensive analysis of the amount of energy required to brood broiler chickens was made. A computer simulation was used to evaluate brooding energy requirements as a function of geographic (or climatic) location, time of year, housing type, and house temperature schedule. Results are presented as the average brooding energy requirement for birds marketed during each of the four calendar quarters and the average for the year. Daily and half-day requirements were also calculated for birds grown during each quarter. Simulation results compare favorably with fuel use survey data reported by Brewer et al. (1978). The results point to complexities inherent in the design of efficient solar heating systems for brooding broiler chickens.
Women as pastoral counselors

Traditionally, it has been woman's function to nurture; that is, to promote well-being. In view of this, it is fitting to consider the extent to which women may succeed as counselors in the pastoral context. Although possibly hindered by prejudicial attitudes in professional relations with male counselees, women pastors can be uniquely effective in their outreach to other women as well as to married couples and children. Ministering roles include those of mother figure, confidante, conciliator, and preceptress for healthy conscience development. In Jungian terminology, a woman pastoral counselor can serve as the “anima” which strives to relate the inner self to Christian values.
Update on human polyomavirus BK nephropathy.

Polyomavirus BK (BKV) has ebeen identified as the main cause of polyomavirus-associated nephropathy, a major cause of renal allograft failure. Although BKV-associated nephropathy develops in only 2% to 5% of renal transplant recipients, its prognosis when present is very poor, with irreversible graft failure developing in 45% of affected patients. While the use of urine cytology for the detection of decoy cells has been in use for decades, other diagnostic modalities to detect BKV have emerged, including tissue biopsy, polymerase chain reaction, viral culture, and serology. Currently, there is no consensus regarding the laboratory technique best suited for clinical monitoring. This review article will discuss essential and clinical features of polyomavirus, followed by a discussion pertaining to the various diagnostic modalities that contribute to detecting polyomavirus-associated nephropathy. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc.
SU-GG-J-148: Planned Target Dose Vs. Delivered Target Dose for Prostate IMRT Treatment

Purpose: Inter‐fraction motion and deformation of a tumor target may result in an altered dose distribution delivered during radiotherapy than planned. On‐board cone‐beam CT(CBCT)imaging was used to study the dose delivered throughout the treatment course to a prostate cancer patient treated with IMRT.Method and Materials:IMRT planning was performed using conventional planning CT. During treatment the patient was positioned using reference skin markers and subsequently adjusted using image guidance based on implanted gold seeds in the prostate. CBCTimages were taken weekly from a Varian Trilogy throughout a seven‐week treatment period and the targets and organs at risk were re‐contoured by oncologists. The original IMRT plan was applied to volumetric CBCT using both the treatment position with and without image guidance. Dose‐volume histograms (DVHs) were calculated. Results: Analysis of DVHs indicates that there is significant variability in the dose delivered to the target region due to inaccuracy of patient positioning and deformation of target contours. The minimum dose to 98% of the prostate PTV calculated without image guidance ranges from 49 to 84% (average 67%), whereas with image guidance the minimum dose ranges from 84 to 99% (average 92%). Bladder and rectal doses with and without image guidance depend on variation in bowel distention and bladder filling. Conclusion: This study provides information of the actual integrated dose that the patient received throughout the entire course. It also suggests that deformations of the PTV due to changing bladder and rectum content are dosimetrically significant such that patient setup achieved using fiducial markers may not be sufficient to ensure adequate dose coverage of the PTV. Additionally, an increased dose to organs at risk such as rectum and bladder may be prevented with this emerging technique. Conflict of Interest: The research is partially supported by a Varian research grant.
Isolation and field-inversion gel electrophoresis analysis of DNA markers located close to the Huntington disease gene.

Abstract A radiation-induced hybrid cell line containing 10–20 million base pairs of DNA derived from the terminal part of human 4p16 in a background of hamster chromosomes has been used to construct a genomic library highly enriched for human sequences located close to the Huntington disease (HD) gene. Recombinant phage containing human inserts were isolated from this library and used as hybridization probes against two other radiation hybrids containing human fragments with chromosomal breaks in 4p16 and against a human-hamster somatic cell hybrid that retains only the 4p15-4pter part of chromosome 4. Of 121 human phage tested, 6 were mapped distal to the HD-linked D4S10 locus. Since the HD gene is located between D4S10 and the 4p telomere, all of these sequences are likely to be closer to HD than D4S10, and any one of them may be a distal flanking marker for the disease locus. Long-range restriction map analysis performed with a field-inversion gel system shows that the six new loci are distributed in different places within 4p16. Although it is not possible to establish an order for the six sequences with the FIGE data, the results demonstrate that the region detected by these probes must span at least 2000 kb of DNA.
Prevalence of dental caries and dental fluorosis in areas with negligible, optimal, and above-optimal fluoride concentrations in drinking water.

A cross-sectional study was conducted of 1,123 children aged 8 to 16 years who were lifelong residents of communities with varying levels of natural fluoride in drinking water. Data on the prevalence of dental caries and dental fluorosis are presented. The prevalence of dental caries and dental fluorosis was assessed in 1,123 children aged 8 to 16 years who were lifelong residents of areas with negligible, optimal, and above-optimal concentrations of natural fluoride in drinking water. Caries prevalence in the optimal fluoride area was 38.1 % lower than it was in the negligible fluoride area, and, in the higher-than-optimal fluoride areas, even greater caries protection was evident. Caries protection was compromised in children with severe fluorosis. Findings do not support the contention that definite increases in the prevalence of fluorosis are occurring in communities with negligible and optimal water-fluoride concentrations because of increased total fluoride consumption from various sources.
The Effects of Preferred Play Partnership on Communication Adequacy

Summary This study investigated the effects of preferred play partnership on the conversational competence of preschool children. The treatment groups were comprised of 11 pairs of children who had demonstrated high levels of mutual interaction in freeplay (preferred partners) and 11 pairs who had engaged in low mutual interaction (nonpreferred partners). Interaction scores were derived using Parten's scale of social participation. Each dyad was video recorded in a IS-minute freeplay session. Speech was analyzed using a modification and extension of Garvey and Hogan's coding scheme. As expected, preferred partners generated more utterances and approximately twice as many relevant response-generating utterances as non-preferred partners. With respect to sequences of three or more utterances, preferred partners produced more sequences of relevant utterances (conversation) and more sequences of irrelevant utterances (collective monologue) than nonpreferred partners. In general, preferred partners appeared to...
The Road to a Project-Based Classroom

Richard Hake, in his landmark 1998 study of introductory physics courses, convinced the physics community that active-engagement strategies produce superior student learning, as measured by pre and...
Standardization of scales in social science research: Breaking the routine

Regression coefficients are generally reported in their original metric or standardized s's. This paper reviews the shortcoming of both and introduces some flexibility into standardization procedures. The procedures suggested facilitate computation, interpretation, and comparison.
Hypergeometric Solutions of Trigonometric KZ Equations Satisfy Dynamical Difference Equations

Abstract The trigonometric KZ equations associated to a Lie algebra g depend on a parameter λ ∈ h where h ⊂ g is a Cartan subalgebra. A system of dynamical difference equations with respect to λ compatible with the KZ equations is introduced by V. Tarasov and the second author (2000, Internat. Math. Res. Notices 15 , 801–829). We prove that the standard hypergeometric solutions of the trigonometric KZ equations associated to sl N also satisfy the dynamical difference equations.
Land Reform in El Salvador and the Chapultepec Peace Accord

The focus of this article is on the land transfer programme (PTT) carried out in El Salvador over the past decade as a result of the 1992 Chapultepec Peace Accord. Building on the agrarian reforms of the 1980s, the PTT beneficiaries were smallholders created by the state and drawn from ex-combatants on both sides (the FMLN, the military) in the war. Among the issues considered are the forms of tenure that resulted, and the agrarian debt incurred. Also examined is the socio-economic profile of the PTT beneficiaries, together with their assessment of the positive/negative impact on their lives of the reform programme. Finally, the achievements and failures of the PTT are evaluated in terms of the wider national/international context, and the resulting contradiction between the objectives of the agrarian reform and the determinants of global markets.
Flexible waveguide enabled single-channel terahertz endoscopic system

Colorectal cancer is the third most commonly diagnosed cancer in the world. The current standard of care for colorectal cancer is the conventional colonoscopy, which relies exclusively on the Physician’s experience. Continuous wave terahertz (THz) imaging has the potential to offer a safe, noninvasive medical imaging modality for detecting cancers. The current study demonstrates the design and development of a prototype terahertz endoscopic system based on flexible metal-coated terahertz waveguides. A CO 2 pumped Far-Infrared molecular gas laser operating at 584 GHz frequency was used for illuminating the tissue, while the reflected signals were detected using liquid Helium cooled silicon bolometer. The continuous-wave terahertz imaging system utilizes a single waveguide channel to transmit the radiation and collect the back reflected intrinsic terahertz signal from the sample and is capable of operation in both transmission and reflection modalities. The two dimensional reflectance images obtained using a prototype terahertz endoscopic system showed intrinsic contrast between cancerous and normal regions of the colorectal tissue, thereby demonstrating the potential impact of terahertz imaging for in vivo cancer detection.
Reduced fertility in male mice following treatment with niridazole.

Nach einmaliger i.p.-Injetion von 700 mg/kg Niridazol wurden manniiche Mause wiederholt mit unbehandelten Weibchen wochentlich uber 2 Monate hinweg gepaart und die Ova gesammelt. Es konnte eine starke Herabsetzung der Befruchtungsraten 3–4 Wochen nach Paarung festgestellt werden, was die Annahme einer Wirkung auf die meiotische Teilung der Spermatozyten und Spermatiden nahelegt. Nach der 7. Woche trat eine Normalisierung der Fruchtbarkeitsrate ein.
Collection efficiencies of bioaerosol impingers for virus-containing aerosols

Abstract Impingers are common bioaerosol sampling instruments. In the last 20 years, impinger performance for collection of viable and non-viable bioaerosols in the 0.1–10 μm size range has been well documented. An ideal impinger has high collection efficiency for particles >0.1 μm. This research explored how well the 500 ml Greenburg–Smith (G–S) impingers collected particles between 0.1 and 2 μm, simulating virus aerosols, with minimal fluid evaporation during sample collection intervals near 60 min. Various impingers have differing dimensions that come into play when collecting viable samples of bioaerosols. The sampling environment can be modified to create optimum impingement conditions. Moderate differences in flow rate and impingement fluid volume may show distinct differences in the capture rate of viable samples within the bioaerosol impinger.
Recent literature on government information

This column was prepared from a manual scan of library and information science journals, and manual or automated searches of sources, with the following headings : government information policy; federal publications and information resources; goverment archives; technology and automated processes; intellectual property; government publications in educational curricula
Prediction of Cushion Performance Less Than One Inch Thick

An important tool packaging engineers use when designing cushions to protect products from shock is the cushion curve. Cushion curves show deceleration values along the vertical axis versus the static loading (weight divided by bearing area) along the horizontal axis for a given thickness of cushion material and given drop height. Commercially available cushion curves display a thickness of one inch and greater. However, many times packaging engineers design packages with cushions less than one inch thick. This leaves the packaging engineer to either guess deceleration levels below one inch thick by trial and error, or to extrapolate from existing cushion curve data. The purpose of this study was to determine if using existing cushion curve information would accurately predict deceleration values below one inch thick. To do this, a procedure was developed comparing information collected from expanded polystyrene cushion samples greater than one inch thick (correlating to existing cushion curves) compared to information collected from samples less than one inch thick. The comparison looked for difference between the datasets. It was found that in fact there was a statistical difference, meaning existing cushion curves should not be used to predict deceleration values for cushion thicknesses below one inch.
Implementation of stochastic dominance: a nonparametric kernel approach

The empirical application of stochastic dominance in the selection of crop alternatives under risk has typically been based on a step function specification of the empirical cumulative distribution function (cdf). This specification has questionable consequences for the analysis, particularly with regards to the tails of the distribution. This article proposes an alternative nonparametric approach based on a nonparametric regression of the cdf. The effect of this alternative specification is then demonstrated using data from Northern Florida. Results are more realistic. The first-degree stochastic dominance results are less discriminating under the new specification while the second-degree results are more discriminating.
Incorporating electron-transfer functionality into synthetic metalloproteins from the bottom-up.

The α-helical coiled-coil motif serves as a robust scaffold for incorporating electron-transfer (ET) functionality into synthetic metalloproteins. These structures consist of a supercoiling of two or more α helices that are formed by the self-assembly of individual polypeptide chains whose sequences contain a repeating pattern of hydrophobic and hydrophilic residues. Early work from our group attached abiotic Ru-based redox sites to the most surface-exposed positions of two stranded coiled-coils and used electron-pulse radiolysis to study both intra- and intermolecular ET reactions in these systems. Later work used smaller metallopeptides to investigate the effects of conformational gating within electrostatic peptide−protein complexes. We have recently designed the C16C19-GGY peptide, which contains Cys residues located at both the “a” and “d” positions of its third heptad repeat in order to construct a nativelike metal-binding domain within its hydrophobic core. It was shown that the binding of both Cd(...
Convexity Analysis of the Dynamic Integrated Model of Climate and the Economy (DICE)

We study the convexity properties of Dynamic Integrated Model of Climate and the Economy (DICE), which is a nonlinear optimization problem. Through some optima-preserving transformations and convex function analysis, we conclude that the DICE model is a hidden convex optimization problem when using the standard parameter values. This result implies that the solutions obtained from the model under these settings are globally optimal and are accurately reflective of the complex economic relationships modeled. We also provide sufficient conditions on the parameter space that assure this property.
Inflation, expectations, and output: Lucas's Islands revisited

This paper examines the underlying assumptions that were used to derive the natural rate hypothesis in Lucas, 1972a , Lucas, 1972b and Lucas (1973) . In both cases, the natural rate result is shown to be a consequence of a debatable assumption: one assumption being proportional transfers, the other being a choice of dating explicitly rejected by other proponents of the new classical school. In either case, changing the assumption transforms the model into one in which expected inflation is strictly more important than unexpected inflation. The result has implications for econometric practice, since structural VARs are often identified by imposing the natural rate hypothesis.
Amphotericin B: delivery systems.

Because the clinical utility of amphotericin B (AmB) is limited by its toxicity of host cells, an important question is how to best direct it specifically to the fungus or at least to the site of infection or, alternatively, how to keep it away from the host cells. One strategy is to use a vehicle other than deoxycholate. In this minireview, we review some of the relevant studies addressing this issue
Wire-guided endobronchial blockade in a patient with a limited mouth opening.

Purpose We report the use of wire-guided endobronchial blockade, a new method of achieving one-lung ventilation, in a patient requiring awake, nasal, fibreoptic intubation for resection of a lung carcinoma.
Induced dynamic polarization charge and current density of a relativistic test particle in a nonequilibrium relativistic beam-plasma system

The effective charge of a test particle in a nonequilibrium beam-plasma system is the sum of the actual charge and the induced dynamic polarization charge surrounding it. Associated with the latter is the induced dynamic polarization current. Expressions are derived for the induced dynamic polarization charge and current density of a relativistic test particle in a nonequilibrium beam-plasma system. These expressions are useful in the calculation of the nonlinear dynamic polarization force on the test particle.
Recovering from interruptions: does alert type matter?

One method for reducing the disruptiveness of interruptions is to present an alert prior to an interruption. Based on the Memory for Goals theory (Altmann and Trafton, 2002), this alert period provides an opportunity to maintain an associative link between the suspended primary task goal and relevant environmental cues which facilitates resumption. This theory does not, however, describe what types of alerts are most effective. Using reaction time and eye movement measures, three different types of alerts were examined to determine which alerts were the most effective and to determine which afforded the greatest opportunity to form an associative link between the suspended primary task goal and relevant environmental cues. Alert conditions resulted in faster resumption times than a no alert condition. There were no differences between the alert conditions themselves, despite eye movement differences reflecting cue association processes. The eye movement data suggest that one fixation is enough to form an associative link which reduces the disruptiveness of interruptions. Keywords: Driver distraction; Language: en
Toward a critical rhetoric of risk communication: Producing citizens and the role of technical communicators

In this article, we build on arguments in risk communication that the predominant linear risk communication models are problematic for their failure to consider audience and additional contextual issues. The “failure”; of these risk communication models has led, some scholars argue, to a number of ethical and communicative problems. We seek to extend the critique, arguing that “risk”; is socially constructed. The claim for the social construction of risk has significant implications for both risk communication and the roles of technical communicators in risk situations. We frame these implications as a “critical rhetoric”; of risk communication that (1) dissolves the separation of risk assessment from risk communication to locate epistemology within communicative processes; (2) foregrounds power in risk communication as a way to frame ethical audience involvement; (3) argues for the technical communicator as one possessing the research and writing skills necessary for the complex processes of constructing...
Collaborative beamforming in wireless sensor networks

Collaborative beamforming (CB) is an energy efficient transmission scheme in wireless sensor networks (WSNs). Despite the promising aspects of CB, its practical implementation remains largely unexplored and the challenges, namely frequency, phase, and data synchronization, must be addressed for successful deployment. We propose a CB protocol with a compatible transceiver architecture. The protocol uses a phase-locked loop (PLL) continuously operating in closed-loop for frequency synchronization, a local two-way phase estimation and remote one-way calibration technique for phase synchronization, and a data entrainment technique to achieve data synchronization with minimal data traffic. The efficiency analysis including carrier jitter demonstrates the feasibility of the proposed CB protocol.
Stochastic properties of switched Riccati differential equations

This paper studies switched Riccati differential equations, whose switching is driven by a Poisson-like random signal. First we show that the expected value of the escape time of a switched Riccati differential equation satisfies an integral equation and then give a sufficient condition for the equation to admit a unique solution. Then we study a switched version of so called extended Riccati differential equations, which are obtained by extending the domain of Riccati differential equations to the Grassmannian manifold. We show that the limiting distribution of the random walk given by the switched stochastic equation converges to a unique invariant measure exponentially fast. The theory of products of random matrices is used to derive this result. We do not require Riccati differential equations to be symmetric.
A comparison of the anabolic effects of parathyroid hormone at skeletal sites with moderate and severe osteopenia in aged ovariectomized rats

Previous studies have shown that parathyroid hormone (PTH) stimulates bone formation and completely restores lost cancellous bone at skeletal sites with moderate osteopenia in relatively young ovariectomized (OVX) rats. The current study was designed to determine whether PTH has similar bone anabolic effects in aged OVX rats and to compare the bone restorative response to PTH at skeletal sites with moderate and severe osteopenia. Female Sprague-Dawley rats were subjected to sham surgery or bilateral ovariectomy at 3 months of age and maintained untreated for the first year after surgery to allow for the development of moderate vertebral osteopenia and severe tibial osteopenia in OVX rats. Groups of baseline control and OVX rats were sacrificed at the end of this pretreatment period. The remaining OVX rats were then treated for 10 weeks with vehicle, antiresorptive agents alone (estrogen, the bisphosphonate risedronate, or calcitonin) or PTH alone. Other groups of OVX rats were treated concurrently with PTH and each of the antiresorptive agents. As expected, the proximal tibia of baseline OVX rats exhibited severe cancellous osteopenia, whereas the first lumbar vertebral body was moderately osteopenic. Treatment of OVX rats with antiresorptive agents alone failed to restore cancellous bone at both skeletal sites, whereas treatment with PTH alone markedly stimulated bone formation and completely restored lost cancellous bone in the lumbar vertebra. PTH also stimulated bone formation in the severely osteopenic proximal tibia of OVX rats but only marginally restored lost cancellous bone, possibly due to an inadequate number of bone spicules to serve as a foundation for new bone formation. Concurrent treatments with PTH and antiresorptive agents did not augment cancellous bone to a greater, or lesser, extent than treatment with PTH alone. The positive results from the moderately osteopenic lumbar vertebra indicate that cancellous bone of aged OVX rats retains its ability to respond anabolically to PTH. However, the negative results from the severely osteopenic proximal tibia of aged OVX rats may provide insight into the failure of the skeletons of some osteoporotic patients to respond adequately to anabolic agents such as fluoride or PTH.
The Development of a Proportionality Concept: Judging Relative Fullness

Abstract Six experiments were performed to investigate children's understanding of a proportionality concept, the concept of fullness. Experiments 1 and 2 were intended to rigorously test Bruner and Kenney's (1966) hypothesized developmental progression for the fullness of a water jar task. The results of the experiments supported Bruner and Kenney's contention that 6-year-olds base their spontaneous judgments of fullness on the relative heights of liquid columns, that 10-year-olds base their judgments on the relative volumes, and that neither age group relies on the proportion of filled to empty space. Experiments 3 through 6 were devoted to testing a variety of possible explanations for why children did not use the Proportionality Rule. These experiments failed to support the hypotheses that nonuse of the Proportionality Rule was due to: (a) misunder-standing of instructions; (b) failure to attend to both filled and empty space within each glass; (c) inability to apply appropriate labels to proportions; or (d) inability to compare the magnitudes of proportions. Instead, it appeared that children of both ages could execute all of these component operations, but did not know how to put them together; simple instruction in how to combine the components led to 90% of the children of each age mastering the Proportionality Rule. The results pointed to the importance of distinguishing between the processes of learning and invention.
Karyotypic Analysis of C-Banded Chromosomes of Diploid Alfalfa: Medicago sativa ssp. caerulea and ssp. falcata and Their Hybrid

Chromosomes of two diploid (2n = 2x = 16) subspecies of Medicago sativa ssp. caerulea and ssp. falcata and their hybrid were studied by C-banding. This study was undertaken to improve the C-banding technique for alfalfa chromosomes, develop a C-banded karyotype of the ssp. caerulea and ssp. falcata, and determine if the same C-banding technique could be used to identify parental chromosomes in hybrids. The chromosomes of ssp. falcata have only centromeric bands and thus individual chromosomes could not be identified. One accession of ssp. falcata displayed an interstitial band in the middle of the long arm on the satellite chromosome. However, chromosome-specific bands were observed in ssp. caerulea enabling the identification of each of the eight pairs of chromosomes and the development of a idiogram. All chromosomes had centromeric bands and a terminal band in the short arm except the satellite chromosome (chromosome 8). Interstitial bands were also observed in the short arms, with the exception of chromosome 7. Chromosomes 1, 2, 3, and 8 each had one prominent interstitial band in their long arm. The satellited chromosome is easy to identify because of the presence of the secondary constriction, two bands located on either side of the nucleolar organizer region, and a large terminal band on its long arm. The differences in banding patterns between these subspecies allowed the identification of parental chromosomes in hybrid cells.
Regulation of Fatty Acid Elongation and Initiation by Acyl-Acyl Carrier Protein in Escherichia coli

Long chain acyl-acyl carrier protein (acyl-ACP) has been implicated as a physiological inhibitor of fatty acid biosynthesis since acyl-ACP degradation by thioesterase overexpression leads to constitutive, unregulated fatty acid production. The biochemical targets for acyl-ACP inhibition were unknown, and this work identified two biosynthetic enzymes that were sensitive to acyl-ACP feedback inhibition. Palmitoyl-ACP inhibited the incorporation of [14C]malonyl-CoA into long chain fatty acids in cell-free extracts of Escherichia coli. A short chain acyl-ACP species with the electrophoretic properties of β-hydroxybutyryl-ACP accumulated concomitant with the overall decrease in the amount of [14C]malonyl-CoA incorporation, indicating that the first elongation cycle was targeted by acyl-ACP. All of the proteins required to catalyze the first round of fatty acid synthesis from acetyl-CoA plus malonyl-CoA in vitro were isolated, and the first fatty acid elongation cycle was reconstituted with these purified components. Analysis of the individual enzymes and the pattern of intermediate accumulation in the reconstituted system identified initiation of fatty acid synthesis by β-ketoacyl-ACP synthase III (fabH) and enoyl-ACP reductase (fabI) in the elongation cycle as two steps attenuated by long chain acyl-ACP.
Parametric studies on the response of equipment in resilient-friction base isolated structures subjected to ground motion

Abstract The response of equipment in resilient-friction base isolated structures subjected to harmonic and earthquake ground motion is investigated. Comprehensive parametric studies on the effect of isolator friction coefficient, subsystem (equipment, structure, isolator) natural period, subsystem damping, and the equipment/structure mass ratio on the equipment response are presented. The results are determined by an accurate and efficient semi-analytical procedure and include interaction effects between the equipment, structure, and base isolator. The study indicates that the resilient-friction base isolator is, in general, effective in reducing the accelerations in lightweight equipment components from the corresponding fixed base case.
Evolution of multiple, mutually orthogonal prolyl-tRNA synthetase/tRNA pairs for unnatural amino acid mutagenesis in Escherichia coli

The site-specific incorporation of unnatural amino acids (UAAs) into proteins in living cells relies on an engineered tRNA/aminoacyl-tRNA synthetase (tRNA/aaRS) pair, orthogonal to the host cell, to deliver the UAA of choice in response to a unique nonsense or frameshift codon. Here we report the generation of mutually orthogonal prolyl-tRNA/prolyl-tRNA synthase (ProRS) pairs derived from an archaebacterial ancestor for use in Escherichia coli. By reprogramming the anticodon-binding pocket of Pyrococcus horikoshii ProRS (PhProRS), we were able to identify synthetase variants that recognize engineered Archaeoglobus fulgidus prolyl-tRNAs (Af-tRNA(Pro)) with three different anticodons: CUA, AGGG, and CUAG. Several of these evolved PhProRSs show specificity toward a particular anticodon variant of Af-tRNA(Pro), whereas others are promiscuous. Further evolution of the Af-tRNA(Pro) led to a variant exhibiting significantly improved amber suppression efficiency. Availability of a prolyl-tRNA/aaRS pair should enable site-specific incorporation of proline analogs and other N-modified UAAs into proteins in E. coli. The evolution of mutually orthogonal prolyl-tRNA/ProRS pairs demonstrates the plasticity of the tRNA-aaRS interface and should facilitate the incorporation of multiple, distinct UAAs into proteins.
Rapid gas chromatographic-mass spectrometric analysis of [15n]urea: Application to human metabolic studies

Abstract A rapid gas chromatographic-mass spectrometric method for [15N] urea analysis is described which is based on the formation of a TFA-urea derivative. The method is extremely sensitive, being capable of detecting less than 0.2 atom % excess [15N]urea in as little as 50 μl of plasma and 10 μl of urine with a coefficient of variation of 11%. The method was used to measure in vivo the disappearance of [15N]urea from plasma and the incorporation of [15N]ammonium acetate into [15N]urea. The values obtained for urea pool size and flux are 4.5 ± 0.30 g nitrogen/total body weight and 16.2 ± 1.34 g nitrogen per 24 h per 1.73 m2. Following the ingestion of [15N]ammonium acetate nearly 90% of the 15N label was incorporated into [15N]urea by 30 min.
Separation of Amino Acid Enantiomers by Micellar Electrokinetic Capillary Chromatography Using Synthetic Chiral Surfactants

Abstract A synthetic chiral surfactant was employed for the enantioselective micellar electrokinetic capillary chromatographic (MECC) separation of amino acid enantiomers derivatized with 6-aminoquinoyI- N -hydroxysuccinimidyl carbamate (AQC). The effect of surfactant concentration and buffer pH on resolution was studied, and the optimized conditions were used to evaluate the method in terms of sensitivity, reproducibility, and linearity. Resolution and α values for 12 AQC-derivatized amino acids are reported. The ability to perform both achiral and chiral separations simultaneously is illustrated in a separation of a mixture of six amino acid enantiomeric pairs, all with baseline resolution. The direct reversal of enantiomer migration order, useful in quantitation and chiral identification, is also shown. Comparisons with other N-protected amino acid derivatives are made in terms of resolution and sensitivity, and the advantages of this chiral MECC technique used in conjunction with the inherent advantages of the AQC derivatizing reagent are discussed.
Temperature measurements in PMMA during downward flame spread in air using holographic interferometry

Temperature distributions within a thermally thick cast slab of poly(methylmethacrylate) (PMMA) during downward flame spread in air were determined by measurements of changes in refractive index of PMMA using a holographic interferometry technique. The surface temperature history was measured with a fine thermocouple as a reference for the interferogram over the glass transition region. Samples with widths of 0.32, 0.47 and 1.0 cm and thicknesses of 1.5 and 2.5 cm were used. The experimental configuration was arranged to make the phenomena two-dimensional in the direction of the laser beam. Detailed temperature and heat flux profiles, especially in the area of the immediate vicinity of the flame foot, were obtained. The results indicate that the surface temperature increases gradually from about 1 cm ahead of the vaporization front and reaches the glass transition temperature about 0.2 cm ahead of the vaporization front. Then, it sharply increases to the vaporization temperature, about 380°C. The visible flame front extends about 0.1 cm ahead of the vaporization front. The measured net heat flux from the gas phase to the sample surface increases sharply from about 1 W/cm 2 to 7 W/cm 2 within a distance of about 0.1 cm from the vaporization front. The net heat transfer rate from the gas phase to the sample is about 57% of the total heat transfer rate to the sample. It is concluded that this net heat transfer from the gas phase plays the dominant heat transfer path to heat the thick PMMA slab instead of conductive heat transfer through the condensed phase, as was previously believed with some question.
The Influence of Religiosity, Gender, and Language Preference Acculturation on Sexual Activity Among Latino/a Adolescents

The purpose of this study was to determine the main and interactive effects of religiosity, gender, and language preference acculturation on sexual activity among 570 Latino/a adolescents from the 2002 National Survey of Family Growth. Results indicated that adolescents who viewed religion as very important, had frequent church attendance, and had more traditional attitudes on sexuality were less likely ever to have sex compared with adolescents who were less religious. Those with frequent church attendance and high traditional attitudes had fewer lifetime and recent sex partners. Unassimilated religious youth were less likely ever to have sex, had fewer lifetime and recent sexual partners, and a later age of sexual debut. Females were less likely to have had sex, had fewer recent and lifetime partners, and had a later age of coital debut than males. Religiosity had a healthy dampening of sexual activity among Latino/a adolescents and, in particular, among those who were less assimilated.
Crystal structure of the DpnM DNA adenine methyltransferase from the DpnII restriction system of Streptococcus pneumoniae bound to S-adenosylmethionine

Abstract Background: Methyltransferases (Mtases) catalyze the transfer of methyl groups from S- adenosylmethionine (AdoMet) to a variety of small molecular and macromolecular substrates. These enzymes contain a characteristic α / β structural fold. Four groups of DNA Mtases have been defined and representative structures have been determined for three groups. DpnM is a DNA Mtase that acts on adenine N6 in the sequence GATC; the enzyme represents group α DNA Mtases, for which no structures are known. Results: The structure of DpnM in complex with AdoMet was determined at 1.80 a resolution. The protein comprises a consensus Mtase fold with a helical cluster insert. DpnM binds AdoMet in a similar manner to most other Mtases and the enzyme contains a hollow that can accommodate DNA. The helical cluster supports a shelf within the hollow that may recognize the target sequence. Modeling studies indicate a potential site for binding the target adenine, everted from the DNA helix. Comparison of the DpnM structure and sequences of group α DNA Mtases indicates that the group is a genetically related family. Structural comparisons show DpnM to be most similar to a small-molecule Mtase and then to macromolecular Mtases, although several dehydrogenases show greater similarity than one DNA Mtase. Conclusions: DpnM, and by extension the DpnM family or group α Mtases, contains the consensus fold and AdoMet-binding motifs found in most Mtases. Structural considerations suggest that macromolecular Mtases evolved from small-molecule Mtases, with different groups of DNA Mtases evolving independently. Mtases may have evolved from dehydrogenases. Comparison of these enzymes indicates that in protein evolution, the structural fold is most highly conserved, then function and lastly sequence.
An Evolutionary View of the Origins and Functions of Avian Vocal Communication

Communication is a substitute for fighting in contests over resources. Communication functions to manage the behavior of other animals without risking direct encounters. Females use communication to assess male qualities as mates, thus sexual selection has influenced communication greatly.The origin of vocal communication is still exhibited in the first land animals, the amphibians. Frogs and toads differ from birds and mammals in that they continue to grow larger after reaching sexual maturity. Larger individuals are able to produce lower pitched calls and they are better fighters than smaller ones. In amphibians, lower pitched calls are both more threatening to other males and attractive to females. Importantly, the physical structure of vocalizations is directly related to the function of these sounds. The relationship between function and a vocalization's physical form is not arbitrary, as is the case with human words.How is the relation between body size and pitch of calls manifested in birds? The body size/sound pitch relationship is more symbolic and best describes the motivation of the calling bird. Birds use low, harsh, vocalizations when aggressive and high, tonal ones when appeasing or fearful. This relationship is described by the motivation-structural rules model, which relates size symbolism to motivation and is derived from the primitive relation between body size and fighting ability. The motivation-structural rules model is useful in producing hypotheses to test the relation between the physical form of vocalizations and their function.Vocalizations used for long distance communication, such as most bird song, is a different matter. Here, motivation is usually not as important as sounding close to others. I develop ranging theory to describe how birds assess their distance from one another. The avian ability to resolve very short time intervals between sounds is used to perceive degradation. Degradation is any change in the song as it travels from the singer, such as from reverberation, changes in frequency or amplitude components above those due to spherical spreading of the sound. By comparing a song in their own memory with one that they hear, they are able to judge the distance over which the sound traveled. Ranging theory helps to explain why song learning evolved in some groups as well as the function of dialects, song repertoires, and song complexity.