cssi/SciSciGPT-SciSciNet huggingface dataset:
Determination of correction factors for a 2D diode array device in MV photon beams

The purpose of this study is to evaluate the dosimetric characteristics of a 2D diode array device (MAPCHECK) and provide correction factors for clinically relevant conditions. Measurements were performed for various collimator settings (5 x 5-40 x 40 cm2), SSDs (80-110 cm), and depths (5-20 cm) for 6 and 15 MV photon beams. The correction factor was determined as the ratio of dose measured by an ionization chamber in a large full scatter water phantom to the dose measured by the MAPCHECK with 30 x 30 cm2 solid water phantom. The total correction factor was separated into three components. The phantom scatter factor was evaluated by taking the ratio of dose measured by MAPCHECK with backscatter material and 30 x 30 cm2 phantom to that by the ionization chamber in an infinite large water phantom renormalized to the reference field size (10 x 10 cm2). This was also compared to the theoretical calculation using ratios of phantom scatter factor between an infinitely large water phantom and 30 x 30 cm2 solid water phantoms. The backscatter effect was determined by taking the ratio of the MAPCHECK measurements with and without 10 cm thick solid water backscatter material also normalized to the reference field size at the depth of measurement. The extra correction factor is defined as the ratio of dose measured by the MAPCHECK (without backscatter) to that measured by the ionization chamber in a large water phantom at depth d for the reference field size (10 x 10 cm2) normalized to the reference depth (10 cm) and reference field size. The total correction factors for 6 and 15 MV photon beams were up to 16% and 11.5%, respectively, due to the difference in phantom scatter in MAPCHECK measurements when the field sizes are larger than 30 cm. The result was consistent with theoretical analysis with phantom scatter alone. The backscatter correction factor varied by up to 2% and increased with increasing field size. The extra correction factor decreases with depths and is < 0.4% for all depths. The authors have verified that correction factors for MAPCHECK are a function of the scaled field size and depth only and are independent of the SSD. Results were verified for off-axis points measured by MAPCHECK.
Effects of Training in Test-Taking Skills on Achievement Test Performance: A Quantitative Synthesis

AbstractTo estimate the effectiveness of training programs in test-taking skills on elementary and secondary achievement, test performance quantitative indices of effect magnitude were calculated from statistical data in 24 studies. The mean of the study-weighted effect sizes is .33 which suggests average percentiles on learning outcomes of 63 and 50 respectively for experimental and control groups. Training programs which continue for five weeks or longer produce significantly greater average achievement gains than programs conducted for shorter periods of time. The results support recommendations for programs of training in test-taking skills for elementary and secondary school students.
An interactive environment for object-oriented music composition and sound synthesis

Kyma is an object-oriented environment for music composition written in Smalltalk-80, which, in conjunction with a microprogrammable digital signal processor called the Platypus, provides the composer with a means for creating and manipulating Sound objects graphically with real-time sonic feedback via software synthesis. Kyma draws no distinctions between the materials and the structure of a composition; both are Sound objects. When a Sound object receives a message to play, it transforms itself into a microSound object, i.e. an object representation of itself in the microcode of the Platypus. Thus an object paradigm is used not only in the representation of Sound objects in Smalltalk-80 but also in the microcode representation of those Sound objects on the Platypus.
A regulator for aircraft D-C generators

IN ORDER to self-excite and regulate a d-c generator, a device is needed which can vary the current supplied to the shunt field of the machine so that regulated voltage results over a wide range of speed and load. In addition, it must provide some means of load sharing when one generator and its regulator are paralleled with one or more identical systems. In 71 C ambient, this can be accomplished by a carbon-pile regulator or by a switching-type regulator using germanium transistors.
Dynamics of Lieb-Liniger gases.

It is proved that the Lieb-Liniger cusp condition implementing the delta function interaction in one-dimensional Bose gases is dynamically conserved under phase imprinting by pulses of arbitrary spatial form, and the subsequent many-body dynamics in the thermodynamic limit is expressed approximately in terms of solutions of the time-dependent single-particle Schrodinger equation for a set of time-dependent orbitals evolving from an initial Lieb-Liniger-Fermi sea. As an illustrative application, a generation of gray solitons in a Lieb-Liniger gas on a ring by a phase-imprinting pulse is studied.
Functional and molecular characterization of single serial killer CAR+ T cells demonstrates adaptive modification of behavior and fate based on tumor cell density

Meeting abstracts T cells genetically modified to express a CD19-specific chimeric antigen receptor (CAR) for the investigational treatment of B cell malignancies comprise a heterogeneous population, and their ability to persist and participate in serial killing of tumor cells is a predictor of
A Note on Differences Between Operator‐Level and Function‐Level Equations of Motion

The primary purpose ot this fiole is to demonstrate that there are important differences between the operator and tunction equalities which arise in using the Heisenberg equation ot motion [1] (EOM) in maDy-body physics and chemistry. The pedagogical remarks presented here are offered in the hope that they will help others to avoid drawing talse conclusions because ot a Jack ot understanding. Let us begin by assuming that we are treating a system which consists ot electrons moving in the potential field V(i') ot one or maTe fixed positively charged nuclei, such as would be the case tor electrons in a molecule. Then the many-electron Hamiltonian H tan be writtenin second quantization notation [2] (in atomic units) as
RhoA signaling in cardiomyocytes protects against stress-induced heart failure but facilitates cardiac fibrosis

The Ras-related guanosine triphosphatase RhoA mediates pathological cardiac hypertrophy, but also promotes cell survival and is cardioprotective after ischemia/reperfusion injury. To understand how RhoA mediates these opposing roles in the myocardium, we generated mice with a cardiomyocyte-specific deletion of RhoA. Under normal conditions, the hearts from these mice showed functional, structural, and growth parameters similar to control mice. Additionally, the hearts of the cardiomyocyte-specific, RhoA-deficient mice subjected to transverse aortic constriction (TAC)-a procedure that induces pressure overload and, if prolonged, heart failure-exhibited a similar amount of hypertrophy as those of the wild-type mice subjected to TAC. Thus, neither normal cardiac homeostasis nor the initiation of compensatory hypertrophy required RhoA in cardiomyocytes. However, in response to chronic TAC, hearts from mice with cardiomyocyte-specific deletion of RhoA showed greater dilation, with thinner ventricular walls and larger chamber dimensions, and more impaired contractile function than those from control mice subjected to chronic TAC. These effects were associated with aberrant calcium signaling, as well as decreased activity of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and AKT. In addition, hearts from mice with cardiomyocyte-specific RhoA deficiency also showed less fibrosis in response to chronic TAC, with decreased transcriptional activation of genes involved in fibrosis, including myocardin response transcription factor (MRTF) and serum response factor (SRF), suggesting that the fibrotic response to stress in the heart depends on cardiomyocyte-specific RhoA signaling. Our data indicated that RhoA regulates multiple pathways in cardiomyocytes, mediating both cardioprotective (hypertrophy without dilation) and cardio-deleterious effects (fibrosis).
Foucault's new functionalism

Each of Foucault's major theoretical expositions of the concept of power his critique of Rusche and Kirchheimer at the beginning of Discipline and Punish, his discussion of the "apparatus [dispositif]" of sexuality in The History of Sexuality, volume 1, and his response to questions posed by Dreyfus and Rabinow in the late essay "How is Power Exercised?" reiterates various methodological precautions.1 Power, Foucault argues, is not a property, a possession, a commodity one can exchange for something else, a resource, or an institution. Further, power is not a function of law, morality, repression, or the economic base. Commentators have energetically exposed the culprits of these methodological errors, writers and schools of thought whose names Foucault rarely mentions Durkheim, Weber, classical Marxism, phenomenology, depth hermeneutics, Lukhcs, Marcuse and the Frankfurt School, Althusser, and Habermas.2 Foucault's theory of power is closely linked to concrete empirical studies, which in turn contribute to the refinement of his theoretical tools. Such is not the case, however, with Foucault's concept of resistance, which he articulated solely in theoretical terms. Foucault has asserted in essays and interviews that every power relation is accompanied by points of resistance, such that as he puts it in Volume 1 of the History of Sexuality "resistance is never in a position of exteriority in relation to power (HS, 95)." But in spite of his repeated theoretical claim that resistance is the "irreducible opposite (HS, 96)" of power, this former concept received little attention in Foucault's historical studies. Why did Foucault insist on the centrality of resistance to all power relations but devote his studies of modernity almost exclusively to an analysis of modern forms of power, without ever examining corresponding forms of resistance?
Combined of vector field and linear quadratic Gaussian for the path following of a small unmanned helicopter

In this study, a composite fight control method for the path following of a small unmanned helicopter is proposed. The control system design adopts the hierarchical control architecture that is composed of an inner-loop, an outer-loop and a planning layer. The inner-loop controller design is based on the setpoint tracking linear quadratic Gaussian control technique which can not only stabilise the dynamics of the helicopter, but also track the reference control signals provided by the outer-loop controller well. The core part of the outer-loop controller design is based on the notion of vector field, which is used for generating the desired heading rate command. Lyapunov stability arguments are applied to demonstrate the asymptotic approximation to the desired path in the presence of wind disturbance. Experimental results are presented to verify the validity of the method.
Forced Commutation Performance of Vacuum Switches for HVDC Breaker Application

Tests were conducted to determine performance limits for vacuum switches under forced commutation conditions associated with a highvoltage dc (HVDC) breaker. Circuit parameters were varied and both linear and saturable reactors were used. Single as well as two series breaks were tested. Both ac- and dc recovery voltages were applied. Results confirm that the critical parameters are the current to be interrupted and the time to drive the switch current to zero. A linear reactor works nearly as well as a saturable reactor. Also, the magnitude of current injection need not be matched to the fault current; excess charges preferred.
Midpregnancy genitourinary tract infection with Chlamydia trachomatis: association with subsequent preterm delivery in women with bacterial vaginosis and Trichomonas vaginalis.

Objective The objective of the study was to estimate whether midpregnancy genitourinary tract infection with Chlamydia trachomatis is associated with an increased risk of subsequent preterm delivery. Study design Infection with C. trachomatis was determined using a ligase chain reaction assay (performed in batch after delivery) of voided urine samples collected at the randomization visit (16 0/7 to 23 6/7 weeks' gestation) and the follow-up visit (24 0/7 to 29 6/7 weeks) among 2470 gravide women with bacterial vaginosis or Trichomonas vaginalis infection enrolled in 2 multicenter randomized antibiotic treatment trials (metronidazole versus. placebo). Results The overall prevalence of genitourinary tract C. trachomatis infection at both visits was 10%. Preterm delivery less than 37 weeks' or less than 35 weeks' gestational age was not associated with the presence or absence of C. trachomatis infection at either the randomization (less than 37 weeks: 14% versus 13%, P =.58; less than 35 weeks: 6.4% versus 5.5%, P =.55) or the follow-up visit (less than 37 weeks: 13% versus 11%, P =.33; less than 35 weeks: 4.4% versus 3.7, P =.62). Treatment with an antibiotic effective against chlamydia infection was not associated with a statistically significant difference in preterm delivery. Conclusion In this secondary analysis, midtrimester chlamydia infection was not associated with an increased risk of preterm birth. Treatment of chlamydia was not associated with a decreased frequency of preterm birth.
An efficient method for generating poxvirus recombinants in the absence of selection.

The use of selectable markers (ecogpt) and selection pressures to aid in detection of poxvirus (Vaccinia, VV) recombinants has been implicated in the unintended introduction of second site mutations. We have reinvestigated the use of the helper virus system described by Scheiflinger et al. [1] and adapted by Yao and Evans [2] which produces recombinants at a high frequency in the absence of any selection, at a rate of 6–100%. Our system uses fowlpox virus (FPV) as the infectious helper virus which in infected cells provides the enzymatic apparatus for transcription and replication of a purified, transfected VV genome and for recombination with a second transfected PCR generated DNA fragment. To optimize the system, a PCR DNA fragment was generated that contained poxvirus promoter driven gfp and lacZ genes inserted within the coding sequences of the viral thymidine kinase gene. This PCR fragment was co-transfected together with VV genomic DNA. Recombinant VV was identified by plaquing the mixture on cells non-permissive for FPV and selection of green fluorescent or LacZ positive recombinant vaccinia plaques. The system was optimized using FPV permissive cells (CEF) and non-permissive cells (A549, CV-1) for both the initial infection/transfection and the subsequent selection. Up to 70% of the progeny vaccinia virus contained the gfp/LacZ insertion. In order to test for the presence of FPV/VV intertypic recombinants or other unintended mutations, recombinant wtVV (RwtVV) was regenerated from the gfp/LacZ viruses and evaluated by RFLP analysis and pathogenesis in animals. While all RwtVVs were viable in cell culture, in many of the RwtVV isolates, RFLP differences were noted and while some recombinant viruses exhibited wild type behavior in mice, a wide range of virulence indicative of unintended changes suggests that mutants created by “rescue” systems require careful analysis particularly before use for in vivo studies employing animal models.
Surface active N-acylglutamate: II. Physicochemical properties of long chain N-acylglutamic acids and their sodium salts

The physicochemical properties of long chain N-acylglutamic acids (AGA) and their sodium salts (AGSn) are described. The solubility, Krafft point, pH value, critical micelle concentration, surface tension and foaming power were measured. The properties of the optically active AGA or AGSn differed from those of the corresponding racemates, especially in solubility. The monosodium salts generally had high Krafft points, but monosodium N-oleoylglutamate had a low Krafft point. The monosodium salts hydrolyzed in the diluted aqueous solution to liberate the AGA. The aqueous solutions of the monosodium salts had low surface tensions and good foaming properties. The disodium salts were highly soluble in water, while surface tensions and foaming properties were inferior to those of the corresponding monosodium salts.
From Silos to Scaffolding: Engaging and Effective Social Work Practice

In this final article of the special issue Beyond the Manual: Using Data and Judgment in Clinical Social Work Practice, we extend the discussion regarding the use of data and judgment. We discuss the multiple sources of data used in practice, including research evidence, client perspectives and experience, moment-by-moment process observation, and client feedback regarding progress towards specific, desired outcomes. We move beyond current debates purporting one framework over another to propose a synthesizing framework that situates evidence-based practice, empirically supported interventions and common elements/mapping and adapting practice within a common factors scaffolding framework. This framework provides a way for social workers to effectively make sound judgments using research and client data within the demands of contemporary practice. The article provides a brief overview of the four practice approaches followed by the proposed scaffolding framework and rationale, and concludes with implications for practice, professional education, and research.
In the Manner of Friends: Learnings from Quaker Practice for Organizational Renewal

Tells the story of Quaker meeting, drawing on readings and experiences of the author over the past three years. Describes common practices and key features of the Quaker way, including Meeting for Worship, committees and governance, fellowship, and Meeting for Business. Provides a view of Quaker practice and its effects in a secular setting. Argues that renewal in the sense of restoration and refreshment of vigour and human spirit are warranted in today′s society and work settings, and that the Quaker way can provide useful guidance in such an effort. The change strategy developed works from the “person‐out” rather than from the top down or the bottom up.
Thermodynamic properties of small zinc clusters based on atomistic simulations

Molecular-dynamics calculations were performed on zinc atom clusters to determine their equilibrium configurations using an embedded-atom method (EAM) potential developed for zinc. Calculation of the thermodynamic properties at different temperatures involved a Monte Carlo scheme in conjunction with statistical mechanical techniques. The harmonic approximation was used in the calculation of the vibrational contribution to the cluster partition function and the rigid-body approximation was used in the calculation of the rotational contribution. These calculations were used to examine the Helmholtz free energy of formation of the clusters as a function of cluster size, temperature and pressure with the aim of determining the nucleation rates and critical supersaturation pressures. Three cluster-growth patterns were considered in all the calculations and stability diagrams were plotted indicating the relative stability of clusters as a function of cluster size and temperature for these three growth patterns.
Striatal microinfusion of Tourette syndrome and PANDAS sera: failure to induce behavioral changes.

Rodent striatal microinfusions have been suggested as a model for assessing the behavioral effects induced by antineuronal antibodies. We used this approach to evaluate the proposed autoimmune etiology for Tourette syndrome (TS) and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS). Sera were assessed from patients with TS (n = 9) preselected based on the presence of elevated enzyme-linked immunosorbent assay optical densities against putamen homogenate and sera from patients with PANDAS (n = 8), selected from a larger group assayed for antibodies against a putamen synaptosomal preparation. The effect of antibodies against the streptococcal M5 protein were also studied. A total of 44 Fischer rats received bilateral infusion of sera: 23 ventral striatum (5 PANDAS, 5 TS, 5 anti-M5 protein, and 8 control); 21 ventrolateral striatum (5 PANDAS, 5 TS, 5 anti-M5 protein, and 6 controls). Cannulas were placed bilaterally and symmetrically by stereotactic techniques. After animals were allowed to recover for 1 week, sera were microinfused for 3 days. Animal behavior was then simultaneously quantified by daily observation and monitoring using automated activity boxes for 10 days after infusion. No significant alterations in stereotypic behavior or movement were observed between the PANDAS, TS, or anti-M5 protein and control groups. Our findings are in contrast to previous reports, and suggest the need for further investigations to determine the validity of the model and of autoimmune-mediated hypotheses for pediatric movement disorders. © 2003 Movement Disorder Society
Enabling distributed detection with dependent sensors

Computational issues affecting the feasibility of optimal distributed detection with correlated measurements are well recognized. We propose utilizing the t-cherry junction tree, an approach based on probabilistic graphical models, to approximate the joint distribution of the correlated measurements. In principle, this approach provides a sequence of progressively more efficiently represented approximations that enable tradeoff between fidelity and compactness. Practically, however, the impact of generating estimated distributions from training data can be significant as the number of parameters to estimate in a distribution grows exponentially with the number of random variables in the distribution. This limitation is quantified and the performance of this approach is illustrated via simulation studies.
88 DESMOPRESSIN THERAPY FOR ENURESIS

To determine the effectiveness of desmopressin (DDAVP, a vasopressin analogue) for treating enuresis, we performed a double-blind crossover study at three medical centers. Subjects (N=43) ranged from 6 to 16 years old, had normal renal function and denied polyuria, polydipsia and daytime incontinence. The study encompassed four consecutive two-week periods: pre-treatment, treatment with placebo or DDAVP (40 mcg intranasally at 8 PM), crossover treatment, and post-treatment. DDAVP did not produce adverse side effects or significantly alter blood pressure, body weight, serum osmolality or urine osmolality. The results were as follows: Thirteen of 43 children responded to DDAVP (number of wet nights <6). In 6 of the responders, the drug effect persisted into the next study period. Only 2 of 24 children responded to placebo during the first treatment period. In conclusion, DDAVP appears safe for treating enuresis. A child's response to the drug can be determined by a two-week therapeutic trial.
Structure of the stably-stratified boundary layer during the SESAME-1979 experiment

Airplane measurements in the stable boundary layer during the SESAME-1979 experiment (southcentral Oklahoma, U.S.A.) are examined in terms of the local similarity theory. The obtained results are compared with data from the Minnesota (1973) experiment and with data collected previously on towers in Cabauw (Netherlands) and Boulder (Colorado, U.S.A.). The comparison indicates that the SESAME data are strongly influenced by the terrain features of the experimental site.
Hydrodynamic drag versus roughness for rotating disks

Abstract Stylus measurements of the microroughness of rotating disks and their significant correlation with hydrodynamic drag measurements were studied. The roughest disks (Ra ≈ 16 μm) were found to have drag coefficients about 30% greater than those of the smoothest disks (Ra ≈ 0.14 μm). For a Reynolds' number of 1.5 × 106, the following empirical relationship between the drag coefficient C, the average roughness Ra and a parameter designated the peak count wavelength λpc was obtained: C= bR a λ pc 1 2 + C o where b = 3.85 × 10 −3 μm − 1 2 and C 0 = 6.48 × 10 −3 . Other surface parameters and functions were measured in addition to Ra and λpc; however, it seems that knowledge of an amplitude-sensitive parameter and a wavelength-sensitive parameter is adequate for characterizing increases in the drag of rotating disks due to surface roughness. Ra is the preferred amplitude-sensitive parameter because it is the most widely used. We propose λpc as the wavelength parameter because it is sensitive to the larger profile features rather than to the fine structure. However, there is a need for all workers in the field to standardize on measuring the same parameters so that the results of one group can be easily related to the work of other groups.
Women in Medicine: Traditional Biases and Emerging Trends

A great deal of prejudice exists against women in the medical profession in the United States as is evidenced by the small number of women physicians. The bias begins early in childhood and it takes considerable determination for a young girl to ignore the stereotype of her image.
The action of antitumor agents: A double-edged sword?

Although cytotoxic immunosuppressive agents play an unquestionably useful role in treating many neoplastic and non-neoplastic disorders, there is accumulating evidence that the toxicity associated with their use is considerable. The therapeutic successes obtained with antitumor agents have led to increases in the life span of cancer patients, but have also provided the opportunity for this toxicity to become manifest. A search of the available literature was carried out, with emphasis on cases in which a malignancy developed in patients following chemotherapy for either neoplastic or non-neoplastic (e.g., renal transplantation, psoriasis) conditions; particular focus was given to the incidence of acute myelogenous leukemia in various groups of Hodgkin's disease and multiple myeloma patients. That patients with nonmalignant conditions treated with cytotoxic immunosuppressive agents are also at increased risk of developing a malignancy raises the possibility that these agents may have oncogenic potential. Therefore, one may be faced with the paradox that the patients benefiting most from chemotherapy may be at highest risk of suffering its consequences.
Unraveling the substrate-metal binding site of ferrochelatase: an X-ray absorption spectroscopic study.

Ferrochelatase (EC 4.99.1.1), the terminal enzyme of the heme biosynthetic pathway, catalyzes the insertion of ferrous iron into the protoporphyrin IX ring. Ferrochelatases can be arbitrarily divided into two broad categories: those with and those without a [2Fe-2S] center. In this work we have used X-ray absorption spectroscopy to investigate the metal ion binding sites of murine and Saccharomyces cerevisiae (yeast) ferrochelatases, which are representatives of the former and latter categories, respectively. Co 2 + and Zn 2 + complexes of both enzymes were studied, but the Fe 2 + complex was only studied for yeast ferrochelatase because the [2Fe-2S] center of the murine enzyme interferes with the analysis. Co 2 + and Zn 2 + binding to site-directed mutants of the murine enzyme were also studied, in which the highly conserved and potentially metal-coordinating residues H207 and Y220 were substituted by residues that should not coordinate metal (i.e., H207N, H207A, and Y220F). Our experiments indicate four-coordinate zinc with Zn(N/O) 3 (S/Cl) 1 coordination for the yeast and Zn(N/O) 2 (S/Cl) 2 coordination for the wild-type murine enzyme. In contrast to zinc, a six-coordinate site for Co 2 + coordinated with oxygen or nitrogen was present in both the yeast and murine (wild-type and mutated) enzymes, with evidence of two histidine ligands in both. Like Co 2 + , Fe 2 + bound to yeast ferrochelatase was coordinated by approximately six oxygen or nitrogen ligands, again with evidence of two histidine ligands. For the murine enzyme, mutation of both H207 and Y220 significantly changed the spectra, indicating a likely role for these residues in metal ion substrate binding. This is in marked disagreement with the conclusions from X-ray crystallographic studies of the human enzyme, and possible reasons for this are discussed.
Tapered beam on elastic foundation model for compliance rate change of TDCB specimen

Abstract A modified beam theory is developed to predict compliance rate change of tapered double cantilever beam (TDCB) specimens for mode-I fracture of hybrid interface bonds, such as polymer composites bonded to wood. The analytical model treats the uncracked region of the specimen as a tapered beam on generalized elastic foundation (TBEF), and the effect of crack tip deformation is incorporated in the formulation. A closed-form solution is obtained to compute the compliance and compliance vs. crack length rate change. The present TBEF model is verified with finite element analyses and experimental calibration data of compliance for wood–wood and wood–composite bonded interfaces. The compliance rate change can be used with experimental critical fracture loads to determine the respective critical strain energy release rates or fracture toughness of interface bonds. The present analytical model, which accounts for the crack tip deformation, can be efficiently and accurately used for compliance and compliance rate-change predictions of TDCB specimens and reduce the experimental calibration effort that is often necessary in fracture studies. Moreover, the constant compliance rate change obtained for linear-slope TDCB specimens can be applied with confidence in mode-I fracture tests of hybrid material interface bonds.
Paleoamospheric temperature structure

Abstract Radiative equilibrium and radiative convective temperature profiles for the Earth's evolving atmosphere been have calculated. If the atmosphere evolved from one rich in carbon on dioxide, and deficient in oxygen, to its present composition, the temperature structure showed considerable change. The models of 3 to 4 billion years ago display steadily decreasing temperatures with altitude, being 185°K at pressures associated with the present-day upper stratosphere. A lapse rate feature similar to the present-day tropopause is not indicated until about 1 billion years ago; but the stratospheric region is approximately 15°K colder than presently found at comparable pressures. Surface temperatures approximately 10°K warmer than at present existed until nearly 1 billion years ago. When the oxygen content exceeded roughly 0.1 times the present level, surface temperatures began to decrease. If biological processes are important to carbon dioxide—ozone variations, such as has been suggested during the Ice Ages, then estimates of surface temperature should include the effects of both gases.
Application of a conversion factor to estimate the adenoma detection rate from the polyp detection rate

Background The adenoma detection rate (ADR) is a quality benchmark for colonoscopy. Many practices find it difficult to determine the ADR because it requires a combination of endoscopic and histologic findings. It may be possible to apply a conversion factor to estimate the ADR from the polyp detection rate (PDR). Objective To create a conversion factor that can be used to accurately estimate the ADR from the PDR. Design This was a retrospective study of colonoscopies performed by board-certified gastroenterologists to determine the average adenoma to polyp detection rate quotient (APDRQ) for all endoscopists, individually and as a group. Setting Academic group practice. Intervention The group average APDRQ was used as a conversion factor for the endoscopist's PDR to estimate the ADR. Main Outcome Measurements The strength of the relationship between the estimated ADR and the actual ADR determined by Pearson's correlation coefficient. Results A total of 3367 colonoscopies performed by 20 staff gastroenterologists were included. The average ADR for all indications, all patient age groups, and both sexes was 0.17 (range 0.09-0.27, standard deviation 0.05). The average APDRQ was 0.64 (range 0.46-1.00, standard deviation 0.13). The correlation between the estimated ADR and the actual ADR was 0.85 (95% CI, 0.65-0.93, P = .000001). Limitations Retrospective study in 1 practice setting with all patient types. Conclusions The use of a conversion factor can accurately estimate the ADR from the PDR. Further study is needed to determine whether such a conversion factor can be applied to different practice settings and patient groups.
Promoted iron Fischer-Tropsch catalysts: characterization by thermal analysis

Abstract The effects of metal and alkali promoters on precipitated iron oxide Fischer-Tropsch catalyst precursors are examined using thermal gravimetry (TG) and differential thermal analysis (DTA). A distinct exotherm corresponding to what appears to be the transformation from FeOOH to Fe 2 O 3 is observed for unpromoted and promoted iron oxides when the promoter's ionic radius is less than approximately 0.7A. The heat released during the exotherm is similar for unpromoted and promoted iron oxides corresponding to this size range. For promoters having ionic radii larger than 0.7A, the exotherm occurs over a broad temperature range. Silica exhibits a unique propensity to stabilize against this transition, and appears to be present as two species. Increased loadings of Si cause a shift from the sharp, narrow temperature range exotherm to the broad transition observed for promoters with larger ionic radii.
Recent randomized controlled trials in otolaryngology.

ObjectiveTo assess recent trends in the prevalence and quality of reporting of randomized controlled trials (RCTs) in 4 otolaryngology journals.Study DesignMethodology and reporting analysis.SettingRandomized controlled trials in 4 otolaryngology journals.Subjects and MethodsAll RCTs published from 2011 to 2013 in 4 major otolaryngology journals were examined for characteristics of study design, quality of design and reporting, and funding.ResultsOf 5279 articles published in 4 leading otolaryngology journals from 2011 to 2013, 189 (3.3%) were RCTs. The majority of RCTs were clinical studies (86%), with the largest proportion consisting of sinonasal topics (31%). Most interventions were medical (46%), followed by surgical (38%) and mixed (16%). In terms of quality, randomization method was reported in 54% of RCTs, blinding in 33%, and adverse events in 65%. Intention-to-treat analysis was used in 32%; P values were reported in 87% and confidence intervals in 10%. Research funding was most often absent or ...
Comparison of diagnostic specimens and methods to evaluate infected venous access ports

Abstract Background : Implanted venous access port infection can be difficult to diagnose and treat. If device removal is necessary, confirming port infection is problematic. Materials and methods : Culture specimens from three sites, catheter tip (Tip), port pocket, and the material within the reservoir (inside), were sent from ports removed for potential infection. The results of these cultures were compared to preremoval peripheral and central blood cultures. Results : Forty-five ports were removed for suspected infection. Confirmed port infection was defined as positive culture(s) from one or more experimental specimen(s). In 29 evaluable cases, the inside specimens were completely predictive. Tip specimens were less accurate, even with a lower diagnostic threshold. In 7 of 19 confirmed infections, only the inside culture was diagnostic. Conclusion : The most predictive culture specimen in a potentially infected port is the thrombotic material inside the reservoir.
A cognitive engineering-based approach to designing hypermedia applications

Abstract Hypermedia systems, characterized by their use of graphics, windowing, and networking, are often advocated as effective tools for information representation and management. Their sophistication demands that software engineers be knowledgeable of user cognitive processes in order to develop systems that are functional, learnable, and usable. Recent cognitive research in human-computer interaction has provided a theoretical foundation for understanding user behavior, but the knowledge has not yet been integrated into a practical design procedure. This paper discusses an approach incorporating theoretical work into the process of designing hypermedia systems. Using this approach results in an understanding of user cognitive requirements, a complete design that matches hypermedia presentations to these requirements, and shortened development time.
Effect of substitutional doping on the 1.7 eV electronic transition of YBa2(Cu1−xMx)3O7−δ for M=Co, Fe, Ni and Zn

Abstract This report is on the variation of the 1.7 eV electronic transition of YBa2(Cu1−xMx)3O7−δ as a function of dopant concentration for M=Co, Fe, Ni and Zn. We have examined the spectroscopic ellipsometric measurement of Co and Fe doped samples from x=0% to 20.0% and Ni and Zn doped samples from x=0% to 9.0%. The 1.7 eV absorption peak is observed for trivalent dopants Fe (for x>;9.0%), Co (for x>2;6.0%) and for an oxygen deficient sample. However, it is not observed for the undoped oxygen rich material and for the divalent dopants, Ni and Zn. The 1.7 eV transition appears only as the material becomes non-metallic and as the hole population in the CuO2 plane is decreased. Our results also show that Zn-doping hs the least effect on the metal-like dielectric behavior. Therefore, the rapid reduction of Tc for Zn doping is not due to a decrease in free carriers. The dependencies of the 1.7 eV feature on oxygen coordination, dopant site occupancy and charge valency support the idea of a bound-excitonic charge-transfer transition from the oxygen to copper in the Cu-O planes.
Mean-square correlation of shift-register sequences

The mean value and the mean-square value of various correlation parameters of linear feedback shift-register sequences are obtained and compared with the corresponding parameters for random sequences. The mean-square correlation parameters for maximal-length shift-register sequences, i.e. pseudonoise or pseudorandom sequences, are considerably better than those for random sequences. The mean-square correlation parameters for Gold sequences are found to be the same as those for random sequences. Thus, performance obtained with shift-register sequences is at least as good as the performance obtained with random coding.
A LONGITUDINAL STUDY OF THE DEVELOPMENT OF MATHEMATICS STRATEGIES AND UNDERLYING COUNTING SCHEMES

The purpose of this study was to determine whether patterns of strategy use in second, third and fourth grade children’s arithmetic supported Steffe’s model of numerical development. In addition to student-generated strategies, we looked at commonly taught algorithms not considered in Steffe’s model to determine whether these algorithms reflected underlying schemes. 206 children were assessed on their strategy use while solving arithmetic problems in the second grade, the third grade and again in the fourth grade. Factor analyses indicated some support for Steffe’s model, but there were exceptions. Not all children progressed in their number knowledge and strategies as a function of schooling and schooling appeared to affect the types of strategies children use independent of underlying schemes.
Lower bounds for bandwidth selection in density estimation

This paper establishes asymptotic lower bounds which specify, in a variety of contexts, how well (in terms of relative rate of convergence) one may select the bandwidth of a kernel density estimator. These results provide important new insights concerning how the bandwidth selection problem should be considered. In particular it is shown that if the error criterion is Integrated Squared Error (ISE) then, even under very strong assumptions on the underlying density, relative error of the selected bandwidth cannot be reduced below ordern −1/10 (as the sample size grows). This very large error indicates that any technique which aims specifically to minimize ISE will be subject to serious practical difficulties arising from sampling fluctuations. Cross-validation exhibits this very slow convergence rate, and does suffer from unacceptably large sampling variation. On the other hand, if the error criterion is Mean Integrated Squared Error (MISE) then relative error of bandwidth selection can be reduced to ordern −1/2, when enough smoothness is assumed. Therefore bandwidth selection techniques which aim to minimize MISE can be much more stable, and less sensitive to small sampling fluctuations, than those which try to minimize ISE. We feel this indicates that performance in minimizing MISE, rather than ISE, should become the benchmark for measuring performance of bandwidth selection methods.
Vocabulary Instruction Within a Multi-Tier Approach

Vocabulary instruction provided within a response-to-intervention (RTI) framework has great potential for supporting the vocabulary development of all students, including those who are most at risk for language and literacy difficulties. The majority of research on RTI has focused on code-based literacy skills such as phonemic awareness and decoding. We believe, however, that a multi-tier approach to vocabulary instruction has great potential for supporting the vocabulary development of all students, including those who are most at risk for language and literacy difficulties. In this article we discuss vocabulary acquisition and the challenges that educators face with providing vocabulary instruction in schools, describe a series of research studies supporting direct vocabulary instruction within an RTI approach, and provide suggestions for future research.
Biodegradable hydrogels based on novel photopolymerizable guar gum–methacrylate macromonomers for in situ fabrication of tissue engineering scaffolds

Abstract Guar gum (GG) is a non-ionic polysaccharide that is found abundantly in nature and has many properties desirable for biomedical applications. In the present work GG with molecular weights ranging from 74 to 210 kDa was modified with glycidyl methacrylate (GMA) to produce a series of water-soluble photopolymerizable guar gum–methacrylate (GG–MA) macromonomers of different molecular weights. We investigated the effects of molecular weight of GG–MA macromonomers from 102 to 216 kDa and with percent degree of methacrylation (%DM) ranging from 14% to 56% on the properties of GG–MA hydrogels. GG–MA hydrogels exhibited a three-dimensional open cell microstructure with an average pore size ranging from ∼10 to 55 μm and an average pore density of from ∼2.4 × 10 6 to 8.6 × 10 7 pores cm −3 . The hydrogels exhibited equilibrium swelling ratios ranging from ∼22% to 63%. The degree of in vitro enzymatic biodegradation of the hydrogels decreased linearly with increasing gel content and the degree of methacrylation of the respective macromonomers. The human endothelial cell line EA.hy926 was photo-encapsulated in the GG–MA hydrogels. Cells remained viable at low macromonomer concentrations, but cell viability decreased sequentially as the macromonomer concentration increased. GG–MA hydrogels with a 0.05 wt.% GG–MA macromonomer concentration revealed excellent endothelial cell proliferation, similar to that of the Matrigel™ control.
Convergence and divergence in the neurochemical regulation of prepulse inhibition of startle and N40 suppression in rats.

Prepulse inhibition of startle (‘PPI’), a cross-species measure of sensorimotor gating, is impaired in schizophrenia patients. Suppression of P50 event-related potentials (ERPs) in response to the second of two clicks (‘P50 gating’) is also impaired in schizophrenia. Suppression of N40 ERPs to the second of two clicks (‘N40 gating’) is thought by some to be a rat homolog of human P50 gating. Emerging evidence suggests differences in the neurobiology of deficits detected by PPI vs P50 (or N40) gating. We recorded PPI and N40 gating contemporaneously in rats, to assess convergence and divergence in the neurochemical regulation of these measures. Dose–response studies examined the effects of apomorphine (APO), phencyclidine (PCP) or the 5HT2A agonist DOI on PPI, and on motor responses to stimuli (S1 and S2) that elicit N40 gating. Effects of optimal drug doses on PPI and N40 gating were then assessed in other rats with implanted cortical surface electrodes. APO, PCP and DOI caused dose-dependent disruptions of both PPI and gating of motor responses to N40 stimuli. Reduced PPI reflected diminished prepulse effectiveness, demonstrated by increased startle levels on prepulse+pulse trials. In contrast, reduced gating of motor responses to N40 stimuli reflected a reduced motor response to S1. In separate rats, robust PPI, N40 potentials and N40 gating could be detected within one test. PPI and N40 gating were disrupted by APO, PCP, and DOI. Again, drug effects on PPI reflected increased startle on prepulse+pulse trials, while those on N40 gating reflected reduced ERP responses to S1. In conslusion, when PPI and N40 gating were studied concurrently in rats, drug effects on PPI reflected reduced inhibition of startle by the prepulse, while diminished N40 gating reflected S1 response suppression. Despite similarities in drug sensitivity, these results suggest that distinct neurobiological mechanisms underlie drug-induced deficits in PPI and N40 gating.
Series Approximations to the Equation of Thermogravimetric Data

THE equation of the plot of thermogravimetric data is useful in kinetic analysis (1–12), but since it contains an exponential integral, many workers prefer approximate expressions. The best balance of accuracy and convenience is achieved by the use of series taken to as few terms as possible, and it is the purpose of this communication to show which of four such abbreviated series approximations most nearly approaches this ideal.
Distribution functions in plasmas generated by a volume source of fission fragments

The role played by fission fragments and electron distribution functions in nuclear pumped lasers is considered and procedures for their calculations are outlined. The calculations are illustrated for a 3He–Xe mixture where fission is provided by the 3He(n,p) 3H reaction. Because the dominant ion in the system depends on the Xe fraction, the distribution functions cannot be determined without the simultaneous consideration of a detailed kinetic model. As is the case for wall sources of fission fragments, the resulting plasmas are essentially thermal but the electron distribution functions are non‐Maxwellian.
The effects of electron temperature in terahertz quantum cascade laser predictions

Quantum cascade lasers (QCL's) employ the mid- and far-infrared intersubband radiative transitions available in semiconducting heterostructures. Through the precise design and construction of these heterostructues the laser characteristics and output frequencies can be controlled. When fabricated, QCL's offer a lightweight and portable alternative to traditional laser systems which emit in this frequency range. The successful operation of these devices strongly depends on the effects of electron transport. Studies have been conducted on the mechanisms involved in electron transport and a prediction code for QCL simulation and design has been completed. The implemented approach utilized a three period simulation of the laser active region. All of the wavefunctions within the simulation were included in a self-consistent rate equation model. This model employed all relevant types of scattering mechanisms within three periods. Additionally, an energy balance equation was studied to determine the temperature of electron distributions separately from the lattice temperature. This equation included the influence of both electron-LO phonon and electron-electron scattering. The effect of different modelling parameters within QCL electron temperature predictions will be presented along with a description of the complete QCL prediction code.