cssi/SciSciGPT-SciSciNet huggingface dataset:
Biopsy marker localization with thermo-acoustic ultrasound for lumpectomy guidance

Purpose Almost one in four lumpectomies fails to fully remove cancerous tissue from the breast, requiring reoperation. This high failure rate suggests that existing lumpectomy guidance methods are inadequate for allowing surgeons to consistently identify the proper volume of tissue for excision. Current guidance techniques either provide little information about the tumor position or require surgeons to frequently switch between making incisions and manually probing for a marker placed at the lesion site. This article explores the feasibility of thermo-acoustic ultrasound (TAUS) to enable hands-free localization of metallic biopsy markers throughout surgery, which would allow for continuous visualization of the lesion site in the breast without the interruption of surgery. In a TAUS-based localization system, microwave excitations would be transmitted into the breast, and the amplification in microwave absorption around the metallic markers would generate acoustic signals from the marker sites through the thermo-acoustic effect. Detection and ranging of these signals by multiple acoustic receivers on the breast could then enable marker localization through acoustic multilateration. Methods Physics simulations were used to characterize the TAUS signals generated from different markers by microwave excitations. First, electromagnetic simulations determined the spatial pattern of the amplification in microwave absorption around the markers. Then, acoustic simulations characterized the acoustic fields generated from these markers at various acoustic frequencies. TAUS-based one-dimensional (1D) ranging of two metallic markers - including a biopsy marker that is FDA-approved for clinical use - immersed in saline was also performed using a bench-top setup. To perform TAUS acquisitions, a microwave applicator was driven by 2.66 GHz microwave signals that were amplitude-modulated by chirps at the desired acoustic excitation frequencies, and the resulting TAUS signal from the markers was detected by an ultrasonic transducer. Results The simulation results show that the geometry of the marker strongly impacts the quantity and spatial pattern of both the microwave absorption around the marker and the resulting TAUS signal generated from the marker. The simulated TAUS signal maps and acoustic frequency responses also make clear that the marker geometry plays an important role in determining the overall system response. Using the bench-top setup, TAUS detection and 1D localization of the markers was successfully demonstrated for multiple different combinations of microwave applicator and metallic marker. These initial results indicate that TAUS-based localization of biopsy markers is feasible. Conclusions Through microwave excitations and acoustic detection, TAUS can be used to localize metallic biopsy markers. With further development, TAUS opens new avenues to enable a more intuitive lumpectomy guidance system that could help to achieve better lumpectomy outcomes.
Prediction of Maximum Allowable Temperatures for Dry Storage of Zircaloy-Clad Spent Fuel in Inert Atmosphere

The most restrictive degradation mechanism for light water reactor spent fuel during a 40-yr dry storage period in an inert atmosphere is creep rupture of the Zircaloy cladding. To develop the best...
Existence: Essays in Ontology

Preface Introduction: inside and outside the ontology room 1. Five questions 2. The new antimetaphysicians 3. Being, existence, and ontological commitment 4. Existence, ontological commitment, and fictional entities 5. Can variables be explained away? 6. Quine's 1946 lecture on nominalism 7. Alston on ontological commitment 8. A theory of properties 9. What is an ontological category? 10. Relational vs. constituent ontologies 11. Can mereological sums change their parts? 12. Causation and the mental.
Summary and Perspectives

Staying alive is something that we do automatically. Health is usually taken for granted; ordinarily, we become aware of it only when something goes wrong, that is, when we experience signals of bodily malfunction, symptoms and signs of disease. While the nature of life itself remains a mystery, a great deal is known about the processes and mechanisms involved in living systems (Miller, 1978).
Teaching College Level Content and Reading Comprehension Skills Simultaneously via an Artificially Intelligent Adaptive Computerized Instructional System

This paper presents a behavioral model for conceptualizing advanced reading comprehension as a “higher order” behavior class. Also discussed are strategies and tactics utilized by an artificially intelligent adaptive tutoring and testing software system designed to shape such comprehension skills while also teaching subject-specific “content” to college students. The system, called MediaMatrix, offers internet delivery of relatively traditional textbook content using highly individualized and adaptive tutorial and assessment procedures (Ray, 1995a; 1995b, 2004). Extant and new research on the effectiveness of this system is presented, with particular emphasis on a preliminary study of students in two small sections of an introductory psychology course. Students were evaluated during early (pre) and late (post) portions of the semester using two equivalent forms of a specially constructed SAT/GRE type reading comprehension test. A statistically significant 17% gain from pre-to-post reading comprehension scores was observed, suggesting that both the behavioral model and the MediaMatrix strategies and tactics for shaping such higher order behaviors merit further research. Practical implications of teaching both specific course content and higher order behaviors such as reading comprehension without direct teacher contact are especially noted.
Which low-income parents select child-care?

Public spending on child-care has grown steadily over the past two decades, flowing to parents in the form of portable vouchers, especially in the wake of the 1996 welfare reforms. At the same time, Head Start and state preschool programs continue to allocate funds directly to neighborhood and school organizations. Little is known about how diverse low-income parents enter this mixed market of child-care providers, then select from among centers and after-school programs, licensed day-care homes, or individual caregivers. Do parents' attributes, along with participation in welfare, affect whether they enter the market or instead rely on nonmarket caregivers, and what type of care they select? To what extent does the local availability of programs condition parental choice? We address these questions, drawing from interviews with 1974 employed parents moving from welfare to work in three California counties. We found that married parents, Latinos, Vietnamese, and non-English speakers, in general, were less likely to select a center or formal after-program, instead relying on home-based providers. Parents with higher school attainment, working longer hours, and earning more were more likely to choose a center or after-school organization. The ages and number of children in the home were related to selection patterns. Non-English speaking parents residing in neighborhoods with more abundant enrollment slots in child-care centers were more likely to choose such a program. We discuss implications for how we theorize about diverse poor families making choices in mixed markets, or being allocated to organized child-care opportunities across variable neighborhoods.
Study of x-ray generation from noble gases mixture jets irradiated by unr FS-Leopard laser with different pulse contrast

Some aspects of physical phenomena occurring when an intense laser pulse with sub-ps duration and intensity > 1018-1019 W/cm2 heats under-dense plasma in supersonic clusters/gas jet from gas-puff system were studied to determine the relative contribution of these processes to soft and hard x-ray emission from debris-free plasmas. Experiments were performed at the UNR Leopard laser operated with 15J / 350 fs and different pulse contrast (107 or 10−5). The supersonic linear (elongated) nozzle generated Ar and Kr clusters/monomer jets as well as jets with Ar/Kr or Ar/Kr/Xe mixtures with density > 1019 cm3. In prior laser heating experiments, all jets were probed with optical interferometry and Rayleigh scattering to measure jet density and cluster distribution parameters. The elongated jet provides the capability to study laser beam self-focusing in plasma that is interconnecting with efficient x-ray generation. The laser radiation flux density in the focal spot was up to 2 × 1019 W/cm2. Plasma diagnostics included x-ray diodes, pinhole cameras and spectrometers. Jet signatures of x-ray emission from pure Ar carrier gas as well as from mixture with lower Kr concentration and Ar/Kr mixture with adding Xe gas, were found to be very different. The most intense x-ray emission was observed in a wide spectral region 1–9 keV from these gas mixtures compared to pure Ar or pure Kr carrier gases. Also, this x-ray emission was strongly anisotropic depending on the direction of laser beam polarization. Non-LTE models have been implemented to analyze the x-ray spectra. It was shown that Ar/Kr jet plasma was hotter than that from pure Kr. X-ray spectra of Ar carrier gas (only “cold” Ka line) were similar to the spectra obtained early from subsonic tube nozzle (no clusters in jet). It can be explained by the fact that Ar in Ar/Kr mixture did not generate clusters as opposed to Kr. Evidence of electron beam generation in supersonic jets' plasma was found. Influence of fs laser pulse contrast level on x-ray emission characteristics is discussed. Future research will focus on the study of cluster formation in linear supersonic jets with Ar carrier gas and Kr and Xe impurities, varying its parameters for optimization of x-ray yield and power. Another goal is to determine optimal conditions for possible application of x-ray source with gas mixture jets at larger sub-ps laser facilities.
Creditor Moral Hazard in Equity Markets: A Theoretical Framework and Evidence from Indonesia and Korea

This paper expands on the work of Sarno and Taylor (1999) and develops three alternative models in which creditor moral hazard might occur in equity markets under different assumptions regarding the existence of asset market bubbles and implicit guarantees. Incorporating IMF-related news associated with the own country and with other countries to our models, we are able to predict the expected change in investor behavior and its effect on stock returns. Using daily stock returns for Indonesia and Korea, we test the ability of the models to predict the expected changes in stock returns on the days of IMF-related news such as program negotiations and program approval. Our results regarding Korea and, to a lesser extent, Indonesia are consistent with the creditor moral hazard models that assume implicit guarantees and asset price bubbles. Our results show that, if there is creditor moral hazard in equity markets, its duration could be measured only by days, suggesting that creditor moral hazard is a short-term phenomenon.
Cost-effectiveness analyses in obstetrics & gynecology. Evaluation of methodologic quality and trends.

Objective To evaluate methodologic quality and trends of cost-effectiveness analyses (CEAs) published in Obstetrics & Gynecology. Study design Ten methodologic principles that should be incorporated in CEAs are used to evaluate CEAs published in Obstetrics & Gynecology from 1966 through 1999. We included articles that were cost-effectiveness or cost-benefit analyses or performed such analyses as part of their studies. Results Thirty-four CEAs met our inclusion criteria. Seven (20%) analyses adhered to 10, five (15%) to 9, and two (6%) to 8 of the 10 methodologic principles. The mean (+/- SD, median) number of principles to which studies adhered was 5.7 (+/- 3.3, 4). Studies had high compliance (> or = 85%) with principles of research questions, probabilities and effectiveness measures. Studies significantly improved over time in adherence to principles of time frame, perspective, costs, incremental analysis, sensitivity analysis, discounting and total score (all P Conclusion The CEAs evaluated adhered to approximately half the methodologic principles for performing CEAs but showed significant improvements in quality over time. Understanding the methodology of CEAs is critical for researchers, editors and readers to accurately interpret the results of the growing body of CEA studies.
Three-Dimensional Ultrasonography and Diagnosis of Placenta Percreta with Bladder Involvement

A 19 year old gravida 4 para 2 woman was admitted withpreterm rupture of membranes at 25 weeks 4 days’ gesta-tion. She had undergone two prior low transverse cesare-an sections. Transabdominal ultrasonography revealed anappropriately grown singleton fetus, oligohydramnios,and a complete anterior placenta previa. Gray scale imag-ing demonstrated little myometrial tissue between the pla-centa and bladder, whereas color flow Doppler imagingrevealed increased vascularity between the bladder andthe placenta. These findings suggested a diagnosis of pla-centa accreta, and a confirmatory MR imaging study wasordered. T1-weighted and T2-weighted images before andafter administration of gadolinium contrast agent wereobtained. Findings were of a marginal anterior placentaprevia with an irregular placenta–lower uterine segmentinterface. After contrast agent injection, early arterialenhancement was seen at the anterosuperior aspect of thebladder before the normal myometrium enhanced. Theoverall impression was of placenta percreta without clearbladder invasion.Since there had been no antepartum hemorrhage and no
Folded-notch dual band ultra-wideband antenna

In this paper, we introduce the folded-notch half-disk antenna to support dual band operation covering 2.4-2.5 and 3.1-10.6 GHz without increasing the antenna size greater than needed for the 3.1 to 10.6 GHz band. Results of a parametric study demonstrate that the frequency notch can be controlled. In addition, antenna characterization results are provided in both the frequency and time domains
Requirements for incorporation of Pr160gag-pol from human immunodeficiency virus type 1 into virus-like particles.

Abstract The roles of the human immunodeficiency virus precursor polyproteins Pr55gag and Pr160gag-pol in viral core assembly were studied in CMT3-COS cells. To do this, the precursors were expressed separately by using a simian virus 40 late replacement vector system described previously. Consistent with previously published data, our results show that the Pr55gag precursor, when expressed alone, was able to form particles which had an immature morphology and that particle formation required the presence of a myristate addition signal at the amino terminus of the precursor. In contrast, the Pr160gag-pol precursor was not able to form particles when expressed alone, although it still underwent proteolytic processing. Coexpression of the two precursor polyproteins from separate vectors in the same cell resulted in processing of the Pr55gag in trans by the protease embedded in Pr160gag-pol and the formation of virus-like particles containing the products of both precursors. Proteolytic processing occurred independently of the presence of a functional myristate addition signal on either precursor. On the other hand, removal of myristate from one or the other precursor had nonreciprocal effects on virus particle formation. Cells expressing Pr55gag lacking myristate and Pr160gag-pol containing it did not produce particles. Cells expressing a myristylated Pr55gag and unmyristylated Pr160gag-pol still produced virus-like particles which contained nearly normal amounts of Pr160gag-pol. The results suggest that the incorporation of Pr160gag-pol into particles is largely determined by intermolecular protein-protein interactions between the two precursor polypeptides.
Inverse Scattering Pulse Design

The inverse scattering solution of the selective RF pulse design problem for two-level quantum systems without relaxation is described. This provides a conceptual framework and effective computational method for the exact design of selective RF pulses in the absence of relaxation. Keywords: NMR RF pulse synthesis; selective excitation; Bloch equation; SLR; inverse scattering; IST; DIST
Management options for early stages of acutely symptomatic macular holes.

Abstract PURPOSE: To evaluate management options for acutely symptomatic stage I macular holes, and vitrectomy with intraocular gas tamponade for advanced stage I macular holes. METHODS: Retrospective noncomparative study. Setting: Clinical practice. Study population: Acutely symptomatic stage I macular holes. Management options: (I) spontaneous resolution with observation −7 eyes; (II) stage I holes developing poor visual acuity of 20/50 or worse during observation −9 eyes undergoing pars plana vitrectomy, posterior vitreous separation, fluid −20% sulfur hexafluoride gas exchange; (III) stage I holes acutely progressing to stage II or III during observation −9 eyes with vitrectomy, posterior vitreous separation, membrane peel, fluid −18% perfluoropropane gas exchange. Main Outcome Measures: visual acuity of 20/40 of better, prevention, or closure of macular hole. RESULTS: Spontaneous resolution developed in 7 eyes with 20/40 or better vision (group I). 8/9 eyes undergoing vitrectomy for advanced stage I holes (group II) did not progress and recovered 20/40 or better vision. 1/9 recovered 20/40 vision after further surgery. 9/9 eyes following acute progression to full-thickness holes (group III) had closed macular holes with recovery of 20/40 vision after vitrectomy. CONCLUSIONS: Stage I macular holes can initially be observed. However, excellent visual and surgical results can be obtained in stage I holes with poor vision, or with acute progression to full-thickness holes.
Anti-oestrogenic and anti-tumour properties of prolonged tamoxifen therapy in C3H/OUJ mice.

Abstract The anti-oestrogenic and anti-tumour properties of a sustained-release preparation of tamoxifen were evaluated in female C3H/OUJ mice. Tamoxifen decreased uterine weight compared with controls in intact mice but caused an initial uterotrophic response for 2 months in ovariectomized mice. Prolonged tamoxifen therapy in ovariectomized mice resulted in a uterine weight no different from controls, but these uteri were eventually (at 6 months) refractory to oestradiol. Spontaneous mammary tumours were detected in female mice between 6 months and 1 year of age during continuous cycles of pregnancy and weaning. A similar tumour frequency occurred after one cycle of pregnancy and weaning initiated at 3 1 2 months. Prolonged tamoxifen, started at 3 1 2 or 4 1 2 months of age (following pregnancy/weaning), reduced the appearance of tumours. Similarly ovariectomy at 3 1 2 months prevented mammary tumorigenesis and prolonged tamoxifen could not increase tumour incidence consistently in ovariectomized mice. Although tamoxifen is oestrogenic in short-term tests the compound has the properties of an anti-oestrogen during prolonged administration.
Gravity duals of fractional branes in various dimensions

We derive type II supergravity solutions corresponding to space-filling regular and fractional D branes on (9{minus}p)-dimensional conical transverse spaces. Fractional Dp-branes are wrapped D(p+2)-branes; therefore, our solutions exist only if the base of the cone has a non-vanishing Betti number b{sub 2}. We also consider 11-dimensional SUGRA solutions corresponding to regular and fractional M2 branes on 8-dimensional cones whose base has a non-vanishing b{sub 3}. In this case a fractional M2-brane is an M5-brane wrapped over a 3-cycle. We discuss the gauge theory intepretation of these solutions, as well as of the solutions constructed by Cvetic and co-workers.
On the maximum of the k-dependent susceptibility for fixed k and T > Tc

Abstract We study the maximum occuring in x ( k , T) for fixed k at a temperature Tmax > Tc. We examine the predictions of both Ornstein-Zernike and ϵ-expansions for the position of this maximum. These are compared with the exact results fot the two-dimensional Ising model.
Dissociative excitation of NO2 by electron impact

Electron-impact-induced vacuum ultraviolet emissions are measured for NO 2 , a species important to discharge phenomena and ozone decomposition in the Earth's atmosphere. A calibrated spectrum for 100 eV incident electrons is presented, along with cross sections for strong emission features between 80 and 160 nm. The dominant NI (2p 34 S°-3s 4 P) emission at 120.1 nm is compared with that of N 2 and used to provide an absolute calibration for all measured cross sections. In addition, 10-300 eV excitation functions for the NI (120.1 nm) and OI (130.4 nm) emissions are presented and interpreted. Comparisons are made with similar measurements of related species, in particular N 2 O and NO. Of interest, it was found that, on average, the variation in the intensity of oxygen and nitrogen emissions could be reasonably explained by the difference in the number of constituent oxygen and nitrogen atoms in each target.
CD4+ T cells are ineffective in clearing a pulmonary infection with influenza type A virus in the absence of B cells.

Abstract Recovery from influenza virus infection is dependent on T cell functions which can be provided either by CD8 or CD4 T cells. To identify the functions involved in recovery promoted by CD4 T cells, we have studied the course of the infection in B-cell deficient μMT mice which had been depleted of CD8 T cells by antibody treatment. Upon infection with PR8 [A/PR/8/34(H1N1)], such B- and CD8 T cell-deficient mice mounted strong CD4 T cell responses that were comparable in size and cytokine secretion to those seen in intact mice. Yet, these B- and CD8 T cell-deficient mice could not clear the infection, in contrast to (CD8-depleted) mice containing both B- and CD4 T cells. These findings indicate that the promotion of the T-dependent antibody response is an indispensable component in the CD4 T cell-dependent recovery process.
Coexistence of three species of leaf-feeding aphids (Homoptera) onBetula pendula.

Three sympatric aphid species of European origin (Euceraphis betulae (Koch),Callipterinella calliptera (Hartig) andBetulaphis brevipilosa Borner) feed onBetula pendula Roth in northern California. The component species of this guild partition resources by plant part, feeding sites within leaves and leaf phenological state. Overall niche overlap between species reached a maximum of 49.9% betweenB. brevipilosa andC. calliptera. Co-occurence ofE. betulae with both other species on leaves was random while co-occurrence ofC. calliptera andB. brevipilosa was aggregated. Morphological features (stylet length and body weight) act to mediate niche organization within this guild.
SI and HCCI Combustion Mode Transition Control of an HCCI Capable SI Engine

The combustion mode transition between spark ignition (SI) and homogeneous charge compression ignition (HCCI) combustion of an internal combustion (IC) engine is challenging due to the distinct engine operating parameters over the two combustion modes and the cycle-to-cycle residue gas dynamics during the mode transition. The control problem becomes even more complicated for a multicylinder engine without camless variable valve actuators. This paper studies the combustion mode transition problem of a multicylinder IC engine equipped with dual-stage valve lift and electrical variable valve timing (VVT) systems. Hardware-in-the-loop (HIL) simulations were used as a tool to develop and validate the proposed control strategies. Based on the HIL simulation results, this paper shows that smooth combustion mode transition can be realized in a few engine cycles. During the mode transition, a model-based linear quadratic tracking strategy was used to track the desired engine manifold pressure through the engine throttle control to maintain the engine AFR in a desired range; the fuel quantity of individual cylinder was controlled via the iterative learning; and engine spark was maintained for the SI-HCCI (or spark assistant) hybrid combustions during the combustion mode transition. The HIL simulations demonstrated the effectiveness of the developed control strategies under both steady state and transient engine operating conditions. As a result, it is feasible to have a smooth combustion mode transition for an HCCI capable SI engine equipped with dual-stage valve lift and electrical VVT systems.
Feeding forward versus feeding backward

The Domjan et al. target article is a valuable summary of a vital field of conditioning and learning. It lists, thumbnails, and organizes classical and recent findings into a useful and familiar structure. Perhaps it is time to consider modern developments in ethology, experimental psychology, and computer science that supersede the traditional structure.
Photoionization Spectroscopy of the Zinc Monoethyl Radical and Its Cation

The spectra of the ZnC2H5 radical and its cation have been recorded by two photoionization techniques, resonantly enhanced multiphoton ionization and zero electron kinetic energy spectroscopy, respectively. The ionization potential of the radical has been determined along with a number of vibrational frequencies in the ground state of the cation and the excited state of the neutral. Based upon the spectroscopic data, models for the metal−carbon bonding in metal alkyl radicals are proposed that predict relative bond strengths for a number of species.
BSEM evaluation of carbonate diagenesis: Benthic foraminifera from the Miocene Pungo River Formation, North Carolina

Backscatter scanning electron microscopy (BSEM) was used to evaluate microdiagenesis in biogenic carbonates of the Pungo River Formation, a phosphate-bearing, Miocene, continental shelf deposit in North Carolina. Results of this new high-resolution technique correlate well to the downsection δ 18 O variation of three species of benthic foraminifera. This technique is useful in the evaluation of diagenesis prior to isotopic analysis for paleoclimatic and paleoceanographic purposes.
Is the FIBROSpect II index effective for determining the stage of fibrosis in patients with chronic hepatitis C

Is the FIBRO Spect II ® index effective for determining the stage of fibrosis in patients with chronic hepatitis C?
The deep waters of the western North Atlantic during the past 24,000 years, and the re-initiation of the Western Boundary Undercurrent

Abstract Changes in composition of benthic foraminiferal faunas in two cores from the North American continental rise (at ∼ 3000 m and ∼ 4000 m depth) and one core from the center of the North American Basin (at ∼ 4600 m depth) reflect changes in the nature of bottom water in the western North Atlantic during the past 24,000 years. During late glacial times the portion of the basin below 4500 m depth was filled with cold, well oxygenated water, probably of local North Atlantic origin. This water was overlain by more than 1500 m of “old”, oxygen-deficient water, of probably southern (Antarctic) origin. A basinwide change of deep water occurred first at about 12,500 yr. B.P., which resulted in a strong vertical differentiation of the water masses. As the deepest water became isolated and was losing oxygen, a western boundary undercurrent became established which carried well-oxygenated water at ∼ 3000 m depth along the continental rise. “Old” oxygen-deficient water reoccupied the levels between these two. A second basinwide change occurred shortly after 9000 yr. B.P., marking the beginning of modern deep-water conditions. The Western Boundary Undercurrent enlarged, moved downslope and flushed out the “old” glacial-age deep water. Norwegian Sea overflow reached its maximum about 4000 years ago. The center of the basin experienced the second change with a delay of about 1000 years, when it filled with Norwegian Sea Overflow Water, and later (after 5000 yr. B.P.) received large proportions of Antarctic Bottom Water. These deep-water events are correlated with the initial retreat of the polar front into the Norwegian Sea, its southward readvance, and the final opening of the Norwegian Sea to the inflow of North Atlantic Drift water.
Origin of the terahertz absorption peak in single-walled carbon nanotubes

Two models for the universally-observed terahertz absorption peak in carbon nanotubes are tested experimentally with infrared and terahertz spectroscopy. The curvature-induced gap theory is disproved by our observation, while plasma resonance theory is partially supported.
Demonstration of an optimized flow cell SFC-FTIR interface

An on-line application of capillary SFC-FTIR for the analysis of five steroids has been demonstrated. Baseline resolution is achieved for all the components of the mixture and IR spectra are obtained which match well with spectra of the neat materials. Also, the injected minimum detectable quantity (IMDQ) of caffeine (approximately 2 ng) under similar chromatographic conditions is demonstrated for this interface. Very low IMDQ's achieved using this flow cell interface will facilitate the use of this technique for the analysis of biological fluids and other materials where very low detection limits are required.
Twilight Transitions and Biological Rhythmicity

IN laboratory investigations of biological rhythmicity, changes in ambient illumination are usually brought about by turning lamps on and off1. The responses of deer mice to artificial bright–dim light cycles with simulated twilight transitions are at present being examined in this laboratory.
Political Representation in Latin America A Study of Elite-Mass Congruence in Nine Countries

The authors combine elite and mass survey data to create indicators of representation for nine nations: Argentina, Bolivia, Brazil, Chile, Colombia, Costa Rica, Ecuador, Mexico, and Uruguay. For th...
Stimulated emission in field-ionized bulk InP

Abstract Bulk laser action has been observed between 78° and 170°K in InP ionized by Gunn domains. Light is emitted in a brief pulse from localized lasing filaments. The threshold is much lower than that for the similar effect in GaAs.
Age-Race Subgroup Compared With Renin Profile as Predictors of Blood Pressure Response to Antihypertensive Therapy

Context.—Renin profiling and age-race subgroup may help select single-drug therapy for stage 1 and stage 2 hypertension.Objective.—To compare the plasma renin profiling and age-race subgroup methods as predictors of response to single-drug therapy in men with stage 1 and 2 hypertension as defined by the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure.Design.—The Veterans Affairs Cooperative Study on Single-Drug Therapy of Hypertension, a randomized controlled trial.Setting.—Fifteen Veterans Affairs hypertension centers.Patients.—A total of 1105 ambulatory men with entry diastolic blood pressure (DBP) of 95 to 109 mm Hg, of whom 1031 had valid plasma and urine samples for renin profiling.Interventions.—Randomization to 1 of 6 antihypertensive drugs: hydrochlorothiazide, atenolol, captopril, clonidine, diltiazem (sustained release), or prazosin.Main Outcome Measure.—Treatment response as assessed by percentage achieving goal DBP (<90 mm Hg) in response to a single drug that corresponded to patients' renin profile vs a single drug that corresponded to patients' age-race subgroup.Results.—Clonidine and diltiazem had consistent response rates regardless of renin profile (76%, 67%, and 80% for low, medium, and high renin, respectively, for clonidine and 83%, 82%, and 83%, respectively, for diltiazem for patients with baseline DBP of 95-99 mm Hg). Hydrochlorothiazide and prazosin were best in low- and medium-renin profiles; captopril was best in medium- and high-renin profiles (low-, medium-, and high-renin response rates were 82%, 78%, and 14%, respectively, for hydrochlorothiazide; 88%, 67%, and 40%, respectively, for prazosin; and 51%, 83%, and 100%, respectively, for captopril for patients with baseline DBP of 95-99 mm Hg). Response rates for patients with baseline DBP of 95 to 99 mm Hg by age-race subgroup ranged from 70% for clonidine to 90% for prazosin for younger black men, from 50% for captopril to 97% for diltiazem for older black men, from 70% for hydrochlorothiazide to 92% for atenolol for younger white men, and from 84% for hydrochlorothiazide to 95% for diltiazem for older white men. Patients with a correct treatment for their renin profile but incorrect for age-race subgroup had a response rate of 58.7%; patients with an incorrect treatment for their renin profile but correct for age-race subgroup had a response rate of 63.1% (P = .30). After controlling for DBP and interactions with treatment group, age-race subgroup (P<.001) significantly predicted response to single-drug therapy, whereas renin profile was of borderline significance (P = .05).Conclusions.—In these men with stage 1 and stage 2 hypertension, therapeutic responses were consistent with baseline renin profile, but age-race subgroup was a better predictor of response.
Excitation rates for plasma impurity measurements by x-ray diagnostics

Measurement of intrinsic and injected impurity concentrations and transport in tokamak plasmas by x‐ray pulse‐height analysis (PHA) and x‐ray imaging (XI) diode arrays requires reliable excitation rates for a number of charge states of a range of elements (Al, Se, Ti, Cr, Fe, Ni, Ge, etc.). Previous PHA measurements at Princeton have relied on a coronal‐equilibrium average of excitation rates for iron, and a prescription for scaling the average rate to nearby elements. For improved accuracy in PHA measurements (using the MIST impurity equilibrium and transport code) and for interpretation of XI data (using an x‐ray simulation code), rates for excitation of dominant charge states by electron impact, dielectronic recombination, and radiative recombination have been calculated from available atomic data and parametrized as a function of atomic number (Z=10–42) and electron temperature (Te =0.1–10.0 keV).
Comparison of two floor mat lead dust collection methods and their application in pre-1950 and new urban houses.

This study investigated commercial floor mats as an alternative method to assess lead in residential dust in inner-city houses. Mats were placed for 3 weeks in interior entryways of 34 row houses built before 1950 and 17 new row houses in Baltimore City. A high volume sampler (an HVS3 floor model cyclone-based vacuum) and a hand-held portable cyclone sampler were used in the laboratory to collect side-by-side samples of mat dust. Both devices yielded comparable estimates of lead dust deposition, dust lead concentration, and dust deposition on field mat samples and had similar sampling efficiencies on mats spiked with various types of standard reference materials. The older houses had significantly higher daily lead dust deposition (GM = 130 μg/ft2/day by HVS3) than the newer houses (GM = 9 μg/ft2/day by HVS3), due to higher dust lead concentrations (GM = 1149 ppm vs GM = 107 ppm by HVS3) and not to differences in daily dust deposition (GM = 118 mg/ft2/day vs GM = 87 mg/ft2/day by HVS3). Mats were found to...
Use of CSCL tool in Java applications programming: a case study

The effectiveness of using a computer supported collaborative learning tool in a college-level Java Programming class is investigated in this paper. As an initial attempt, eight collaborative learning laboratory sessions were created. This paper will discuss students' responses to these sessions and report the difficulties encountered in this experiment, along with suggestions for improvement.
The Resurgence of Foreign Language Study.

A SURVEY of 2,830 colleges and universities recently conducted by the Modern Language Association revealed that the number of students studying foreign languages declined only .07 percent between 1974 and 1977; the survey indicated that enrollments in Spanish, Italian, and Ancient Greek increased and enrollments in French, German, and Russian decreased.' In the 1960's, as a result of social upheaval and the influence of the Vietnam protests, individualized curricula became popular on college campuses across the country and consequently the foreign language degree requirement was weakened or eliminated at many educational institutions. Richard I. Brod, Director of Foreign Language Programs at the Modern Language Association, noted that since 1968 enrollments in foreign languages had fallen 37.4 percent in German, 36.6 percent in French, and 31.7 percent in Russian. Recently, however, spurred on by an increasing public outcry over the drop in Scholastic Aptitude Test (SAT) scores (nationally the drop in score averages since 1963 was 49 points on the verbal section, from 478 in 1963 to 439 in 1977, and 32 points on the mathematics section, from 502 in 1963 to 470 in 1977),2 and the general inability of students to express themselves in English, educators have begun to review the need for a more structured curriculum.
Potentials and problems of economic-ecologic models for management of multi-region systems

Abstract The modeling and management of multi-region economic-ecologic systems provides the general focus for this paper as the authors attempt to couple an extension of the framework of central places, inclusive of decision-making functions, with operational models for the purposes of more effectively depicting, understanding and managing problems of the environment. Significant basic problems encountered in applying state-of-the-art methodologies to regional and multi-regional development questions inclusive of the impact on the ecologic system and environmental quality for purposes of policy determination are outlined. These include the problems of identification of meaningful regions, aggregation of data, establishment of an appropriate framework of activities and commodities, and selecting a relevant set of techniques. An empirical study which has confronted these problems is briefly outlined and examples of the type of policy-relevant information generated by the study are given. Finally, some conceptual thinking on how the existing methodologies might be supplemented to more effectively deal with conflicts which certainly will arise within and between regions and nations regarding environmental management is presented. In this section, the world Is viewed as a multi-level system involving planning and environmental management at all levels, and an attempt is made to determine the optimal distribution of decision-making functions over these levels.
Elevation of the olivine-spinel transition in subducted lithosphere: Seismic evidence

Abstract The top of the olivine-spinel phase change in subducted oceanic lithosphere can be located by the travel times of seismic waves which have propagated through the slab. P-wave travel-time residuals from deep earthquakes in the Tonga island are observed at Australian seismic stations are grouped according to the depth of the earthquake. The change in mean residual with a change in earthquake depth is related to the velocity contrast between slab and normal mantle at that depth. The curve mean residual versus earthquake depth displays a region of markedly increased slope between earthquake depths of about 250 and 350 km. The most probable explanation of this observation is an elevation by 100 km of the olivine-spinel phase change within the relatively cooler slab. No evidence was found for vertical displacements within the slab of any deeper phase changes. A temperature contrast between slab and normal mantle of about 1,000°C at 250 km depth is implied. This finding confirms current thermal models for subducted lithosphere but is inconsistent with the global intraplate stress field unless only a few percent of the negative buoyancy force at subduction zones is transmitted to the surface plates.
Animal digestive strategies versus anaerobic digestion bioprocesses for biogas production from lignocellulosic biomass

Herbivorous mammals and wood-eating insects are fairly effective in the digestion of plant polymers, such as lignocellulosics. In order to improve methane production from the lignocellulosic biomass, several kinds of anaerobic digestion processes derived from animal models have been devised. However, the rates of biodegradation occurring in the anaerobic bioreactors still remain lower than in animal guts. The effectiveness of the digestive systems of those animals results from the concerted action of the various enzymes (e.g. cellulases, xylanases, esterases, ligninases) produced in their guts as well as their integration with mechanical and chemical actions. Powerful pretreatment (prefermentation) operations are integrated to and support efficiently the microbial fermentation system, e.g. the rumination (i.e. mechanical) in ruminants and the secretion of endogenous cellulases (i.e. enzymatic) or the alkaline treatment (chemical) at mid-way in xylophagous insects. The oxygen gradients along the gastrointestinal tract may also stimulate the hydrolytic activities of some microbial populations. In addition, the solid retention time, the digesta flow and the removal of the end-products are well ordered to enable animals to thrive on a complex polymer such as lignocellulose. At the same time, technologies were developed to degrade lignocellulosic biomass, such as the rumen derived anaerobic digestion (RUDAD) process and the rumen simulating technique (RUSITEC), more elaborated and using rumen microbial consortia. Overall, they showed that the fermentation taking place in the rumen fermentation and even in the hindgut are biological processes that go beyond the limited environmental conditions generally found in anaerobic digesters. Hence, knowledge on herbivores' digestion mechanisms might be better exploited in the design and operation of anaerobic digesters. This literature review is a cross-analysis of the relevant information about the digestive strategies of herbivorous and wood-eating animals and the bioengineering techniques in lignocelluloses degradation. The aim is to highlight strategies of animals' digestion simulation for more effective anaerobic digestion of lignocellulosic compounds and other solid residues.
Transformation between SLR/VLBI and WGS-84 reference frames

In geodetic and geophysical applications of GPS, it is important to realize the ephemerides of the GPS satellites and the coordinates of station positions in a consistent reference system. At present, more than one reference system is being used by various GPS users depending on their specific applications. The WGS-84 and various reference frames based on satellite laser ranging (SLR), very long baseline interferometry (VLBI), or a combination of SLR and VLBI are the most commonly used in high precision geophysical applications. The WGS-84 is widely used in applications which rely on the GPS broadcast ephemeris. Station coordinates estimated in one system may have to be transformed to another for further use or for evaluation/comparison purposes. This paper presents a seven-parameter transformation between the WGS-84 and SLR/VLBI reference frames. The GPS double-differenced phase measurements for two consecutive weeks from a set of five Defense Mapping Agency (DMA) sites (defined in the WGS-84 frame) and from an augmented set of fifteen CIGNET sites (defined in the SLR/VLBI frame) were processed in a least squares estimation scheme to determine station coordinates, from which the transformation parameters were determined. A scale difference of about 0.2 ppm and an orientation difference in longitude of about 31 milliarcseconds were found to be the only parameters of significance between the adopted SLR/VLBI and the WGS-84 frames. Transformation between WGS-84 and the ITRF90 is also included, in which the scale difference is the same as before but the longitude rotation is about 16 mas.
Matrix Population Models

Matrix population models are discrete-time structured population models in which individuals are classified into discrete stages (age classes, size classes, developmental stages, spatial locations, etc.).
Characterization and lumped circuit model of ultra-wideband flip-chip transitions (DC 110 GHz) for WAFER-scale packaging

An ultra-wideband flip-chip transition is proposed for wafer level packaging applications. The locally matched flip-chip scheme has an air cavity underneath a flip-chip die and local trenches in the flip-chip bond pad area to provide matching. The measured response up to 110 GHz has a return loss below 20 dB across 96% of the band and has an insertion loss improvement of 2.2 dB at 110 GHz. The design approach is simple and requires no additional space. Also presented is lumped element circuit model for the transition region of conventional and locally matched flip-chip interconnect. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1281–1285, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24326
Inositol 1,4,5-trisphosphate receptors in the endoplasmic reticulum: A single-channel point of view.

As an intracellular Ca2+ release channel at the endoplasmic reticulum membrane, the ubiquitous inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R) plays a crucial role in the generation, propagation and regulation of intracellular Ca2+ signals that regulate numerous physiological and pathophysiological processes. This review provides a concise account of the fundamental single-channel properties of the InsP3R channel: its conductance properties and its regulation by InsP3 and Ca2+, its physiological ligands, studied using nuclear patch clamp electrophysiology.
Enthalpic and entropic stages in α-helical peptide unfolding, from laser T-jump/UV Raman spectroscopy

The alpha-helix is a ubiquitous structural element in proteins, and a number of studies have addressed the mechanism of helix formation and melting in simple peptides. However, fundamental issues remain to be resolved, particularly the temperature (T) dependence of the rate. In this work, we report application of a novel kHz repetition rate solid-state tunable NIR (pump) and deep UV Raman (probe) laser system to study the dynamics of helix unfolding in Ac-GSPEA3KA4KA4-CO-D-Arg-CONH2, a peptide designed for helix stabilization in aqueous solution. Its T-dependent UV resonance Raman (UVRR) spectra, excited at 197 nm for optimal enhancement of amide vibrations, were decomposed into variable contributions from helix and coil spectra. The helix fractions derived from the UVRR spectra and from far UV CD spectra were coincident at low T but deviated increasingly at high T, the UVRR curve giving higher helix content. This difference is consistent with the greater sensitivity of UVRR spectra to local conformation than CD. After a laser-induced T-jump, the UVRR-determined helix fractions defined monoexponential decays, with time-constants of approximately 120 ns, independent of the final T (Tf = 18-61 degrees C), provided the initial T (Ti) was held constant (6 degrees C). However, there was also a prompt loss of helicity, whose amplitude increased with increasing Tf, thereby defining an initial enthalpic phase, distinct from the subsequent entropic phase. These phases are attributed to disruption of H-bonds followed by reorientation of peptide links, as the chain is extended. When Ti was raised in parallel with Tf (10 degrees C T-jumps), the prompt phase merged into an accelerating slow phase, an effect attributable to the shifting distribution of initial helix lengths. Even greater acceleration with rising Ti has been reported in T-jump experiments monitored by IR and fluorescence spectroscopies. This difference is attributable to the longer range character of these probes, whose responses are therefore more strongly weighted toward the H-bond-breaking enthalpic process.