cssi/SciSciGPT-SciSciNet huggingface dataset:
Fostering Collaboration in CSCL

INTRODUCTION Some collaborative learning strategies widely used in face-to-face settings can also be adapted to online contexts. They allow us to master the complex relations between members of large, heterogeneous online learning communities. The authors build on their experience in the application of some of the most well-known strategies and techniques used in online courses, such as jigsaw, peer review, role-play, case study and brainstorming. The use of these strategies in Computer Supported Collaborative Learning (CSCL) environments and the related models describing the social structure of the learning community is discussed, in the attempt to highlight their strengths and weaknesses and investigate the conditions for their applicability. The aim is to inform the design and the management of online learning communities.
Basic Mesoamerican Stone-Working: Nodule Smashing?

While lithic studies in Mesoamerica have dealt thoroughly with the prismatic blade reduction strategy and with heavily retouched specimens, little of interpretive value has been done with the ill-d...
The Reality of Illusion. A Transcendental Reevaluation of the Problem of Cinematic Reality

The paper readdresses the parallel considerations of cinema as both access to an essential, true, objective reality and as a device of deception reproducing the fallacies of a biased and reductive human perception. The claim is that the critical consideration of cinematic mediation in these ambiguous terms stems from the traditional association of cinema with the working of mental mechanisms whose logic, it is argued, follows neatly Kant's transcendental constructivist dualist model of reason and its reality. Kant's idea that our sensible but merely phenomenal experience is produced and projected by our supersensible, transcendental synthetic activity, which `in itself' is as unrecoverable as is the world that it moulds, describes perfectly the imaginary-symbolic regime of cinematic signi cation, whose dual nature has been considered both as a hindrance and as a guarantee of objectivity. Throughout the paper, repeated emphasis is given to the signi cance of Kant's insistence to preserve, and to make palpable through the aesthetic, a noumenal unknown, a pure and never fully assessable objectivity within an increasingly self-referential, self-serving and self-enclosed human reason. It has been this modicum of a humanly inaccessible, yet arguably intuitable `excess,' the pursuit and the promise of modern art, which an aesthetically biased lm theory and practice have sought to foreground. Joining forces with Deleuze, Lyotard, and ioek, as well as with Cocteau, Tarkovsky, Wenders, and Kie±lowski, the paper promotes the necessity of continued belief in a non-human metaphysical dimension, an outside within thought that forever eludes capture.
Increased Persistent Sodium Current Causes Neuronal Hyperexcitability in the Entorhinal Cortex of Fmr1 Knockout Mice

Summary Altered neuronal excitability is one of the hallmarks of fragile X syndrome (FXS), but the mechanisms underlying this critical neuronal dysfunction are poorly understood. Here, we find that pyramidal cells in the entorhinal cortex of Fmr1 KO mice, an established FXS mouse model, display a decreased AP threshold and increased neuronal excitability. The AP threshold changes in Fmr1 KO mice are caused by increased persistent sodium current (I NaP ). Our results indicate that this abnormal I NaP in Fmr1 KO animals is mediated by increased mGluR5-PLC-PKC (metabotropic glutamate receptor 5/phospholipase C/protein kinase C) signaling. These findings identify Na + channel dysregulation as a major cause of neuronal hyperexcitability in cortical FXS neurons and uncover a mechanism by which abnormal mGluR5 signaling causes neuronal hyperexcitability in a FXS mouse model.
Clifford and Sylvester on the Development of Peirce’s Matrix Formulation of the Algebra of Relations, 1870–1882

In this paper I first examine the critical factors that are essential to understanding why Charles Peirce turned to matrices in 1882, twelve years after the algebra he had developed in his 1870 paper could be realized as a quaternion algebra. I shall argue that these factors were the creative influence of Peirce’s friend and colleague, William Kingdon Clifford (1845–1879) in the years prior to 1882, and the setting in 1879–1882 when Peirce and Sylvester were together at JHU. Then I shall demonstrate that Peirce, not Sylvester, deserves the recognition for being the first of the two to show that every associative algebra can be represented by a matrix. [This paper has its roots in Anellis and Abeles, “The Historical Sources of Tree Graphs and the Tree Method in the Work of Peirce and Gentzen” in Modern Logic 1850–1950, East and West, pp. 35-97. Studies in Universal Logic. Birkhauser, Basel, 2016]
NEW EVIDENCE FOR THE EMERGENCE OF A MARITIME BLACK SEA ECONOMY

This article argues that changes in settlement pattern from the Bronze to early Iron Age suggest a new maritime orientation in the economy of the Sinop Promontory. Bronze Age evidence (3rd-2nd millennia BC) suggests a pri- marily land-based economy supplemented by maritime resources, while Iron Age evidence (early 1st millennium BC) indicates a stronger maritime orien- tation. Long-distance overseas interacti on from as early as the 5th millennium is suggested by stylistic parallels between local finds and other Black Sea coasts. Early ceramic parallels probably signal incidental contact resulting from fishing or other maritime activities. Iron Age maritime intensification encouraged coastal settlement with clearer parallels between Sinopean and overseas ceramic and architectural assemblages. Exchange and fishing are likely to have been key components of the Iron Age economy in advance of the Circum-Pontic economic expansion brought about by Greek colonization in the second half of the 7th century BC.
The “Smart Dim Fuse”: A new approach to load control as a distributed energy resource

Aggregation of behind-the-meter distributed energy resources holds promise to provide valuable services to the grid, enabling greater penetration of intermittent renewable energy sources. We propose the Smart Dim Fuse system as an approach to utilize loads for aggregation services. The Smart Dim Fuse, installed on individual circuits at the breaker panel, enables load power control without service interruption via direct AC to AC voltage modulation, while reporting load measurement, identification, and resource a vailability forecasting to the aggregator. Using data from 131 homes, we evaluate the aggregate resource availability, and demonstrate a proof-of-concept prototype of the power electronics needed for this functionality.
Ischemic Strokes Due to Large-Vessel Occlusions Contribute Disproportionately to Stroke-Related Dependence and Death: A Review.

Background: Since large vessel occlusion (LVO) related acute ischemic strokes (AIS) are associated with more severe deficits, we hypothesize that the endovascular thrombectomy (ET) may disproportionately benefit stroke-related dependence and death. Methods: To delineate LVO-AIS impact, systematic search identified studies measuring dependence or death (modified Rankin Scale 3-6) or mortality following ischemic stroke among consecutive patients presenting with both LVO and non-LVO events within 24 hours of symptom onset. Results: Among 197 articles reviewed, 2 met inclusion criteria, collectively enrolling 1467 patients. Rates of dependence or death (mRS 3-6) within 3-6 months were higher after LVO than non-LVO ischemic stroke, 64% vs. 24%, odds ratio (OR) 4.46 (CI: 3.53-5.63, p<0.0001). Mortality within 3-6 months was higher after LVO than non-LVO ischemic stroke, 26.2% vs. 1.3%, OR 4.09 (CI: 2.5-6.68), p<0.0001. Consequently, while LVO ischemic events accounted for 38.7% (CI: 21.8-55.7%) of all acutely presenting ischemic strokes, they accounted for 61.6% (CI: 41.8-81.3%) of poststroke dependence or death and 95.6% (CI: 89.0-98.8%) of poststroke mortality. Using literature-based projections of LVO cerebral ischemia patients treatable within 8h of onset, ET can be used in 21.4% of acutely presenting patients with ischemic stroke, and these events account for 34% of poststroke dependence and death and 52.8% of poststroke mortality. Conclusion: LVOs cause a little more than one-third of acutely presenting AIS, but are responsible for three-fifths of dependency and more than nine-tenths of mortality after AIS. At the population level, endovascular thrombectomy has a disproportionate benefit in reducing severe stroke outcomes.
High resolution 1.3 megapixel extended wavelength InGaAs

Extended wavelength InGaAs detectors grown on InP substrates have been generally used only in single element detectors and low resolution linear arrays. The extended wavelength InGaAs is no longer lattice matched to the InP substrate so it requires buffer layers to be used in the epitaxial growth process to accommodate the strain of the mismatched material. These detectors are generally front side illuminated with wire bonded pads. This work describes the results of extended wavelength InGaAs detector arrays that are backside illuminated which presents many more challenges, including imaging through the buffer layers as well as hybridization to Si Readout Integrated Circuits (ROICs). The buffer layers absorb shorter wavelength light making NIR response challenging. The arrays produced in this work are at high resolution, 1.3 megapixels on small pitch of 12 µm. The imagers have response from 700 nm to <2000 nm while imaging via backside illumination. New processing methodologies were developed to extend the short wavelength response to allow for NIR response by removing the substrate and most of the buffer layers from the structure after hybridization. This has produced material with quantum efficiencies <50% across most of its detection range during TEC cooled operation.
Java Idioms - Exception Handling.

Exceptions are a powerful feature for the propagation and handling of failure of operations. Naive use of exceptions however introduces subtle complexity into a system due to the nonlocal nature of throwing an exception. This paper presents a pattern language of eleven Java idioms which serve as a framework for using exceptions. The patterns help to balance the forces that the overall complexity must be limited, that the code must be modifiable and extensible, the source code must be clear and the overall system must be robust.
LIGAND-GATED Ca2+ RELEASE CHANNELS OF THE SARCOPLASMIC RETICULUM: ELUCIDATING STRUCTURE AND FUNCTION WITH [3H]RYANODINE

Publisher Summary This chapter discusses the structure and the function with [ 3 H]ryanodine, which is a highly specific radioligand for studying the structure and the function of putative ligand-gated Ca 2+ release channels localized at the Terminal Cisternae (TC) of the Sarcoplasmic Reticulum (SR), which may participate in Excitation–Contraction (EC) coupling in striated muscle. Regulation of the [3H]ryanodine binding site in skeletal muscle parallels many of the properties exhibited by Ca 2+ induced release of Ca 2+ from skinned and intact muscle fibers and TC SR vesicle preparations indicating that [3H]ryanodine binds to an open state of the channels involved. [3H]ryanodine allows direct evaluation of whether these diverse inotropic agents influence unrelated and biochemically distinct sites at the SR or or act on a single-channel gating mechanism. Caffeine and adenine nucleotides in tandem act synergistically to influence cooperativity in Ca 2+ activation of [3H]ryanodine binding suggesting different allosteric mechanisms for adenine nucleotides and caffeine perhaps via overlapping domains. Contribution of the Ca 2+ ATPase to the integrity of the Ca 2+ -ryanodine receptor complex is assessed by treating TC SR vesicles with polyoxyethylene-9-laurylether (C12E9), which preferentially solubilizes and separates this protein from the other TC SR proteins.
Case Study of Power System Cyber Attack Using Cascading Outage Analysis Model

Reports about cyber attacks on the Ukraine power grid revealed that one or more malwares were deliberately developed to attack industrial facilities, with power systems as one of the major targets. Once the cyber attackers have access to the power grid control system, an attack could possibly trigger cascading outages and thereby cause a large-scale load loss. Such cybersecurity threats have been considered and studied by the North American Electric Reliability Corporation (NERC) since at least 2012. Thus, the purpose of this paper is to develop a tool, of potential use to government entities, to assess the effects of specific types of cyber attacks that are modeled in the Ukraine attacks. Our previous work has proposed a sequential outage checker based cascading outage analysis (COA) model. In this paper, we apply our COA model to a model of a North American regional interconnection system and perform case studies to simulate analogous system interdictions assuming the cyber attackers gained full control of the system. During the cyber attacks in Ukraine in 2015, attackers opened all breakers using Supervisory Control and Data Acquisition (SCADA) systems in three distribution companies that they previously compromised. This is the most intuitive way for cyber attackers to create power outages once they have access to SCADA. To help assess the effects of such attacks, we further develop the COA model and study the impacts of opening different types of devices of each transmission and distribution company (owner) in the studied North American regional interconnection system.
Assessment for Learning—For Teachers as Well as Students

Assessment plays a critical role in education, for both policy makers and practitioners. These roles encompass issues of both accountability (how well students have learned) and instruction (how to promote higher levels of learning). However, assessment can yield more; the potential of assessment for teacher learning, as a result of both designing of student assessments and evaluating of student responses, has been generally overlooked. This paper outlines the uses of assessment of learning (summative assessment), and assessment to guide learning (formative assessment), and then describes the potential for teacher learning in each of these settings. It argues that at each stage in the process of student assessment—design, calibration, analysis of student responses, and use of assessment results to plan future instruction—opportunities abound for teachers to extend their practice.
Spatial access to health care and elderly ambulatory care sensitive hospitalizations.

Abstract Objectives Ambulatory care sensitive condition (ACSC) admission rates have been widely used as indicators of access to and quality of primary care as well as the efficiency of health systems. This study examines associations of spatial access to health care with both inpatient hospital admissions and emergency department (ED) visits for ACSCs for older adults. This study also compares inpatient hospitalization admissions and ED visits for elderly ACSCs by spatial access to health care. Study design This is a complete hospital discharge dataset study. Methods Hospital discharge data were obtained from all hospital systems in the Coastal Bend area of Texas from September 1, 2009, to August 31, 2012. The enhanced two-step floating catchment area method was adopted to measure spatial access to health care, including primary health care and hospitals. Multivariable regression methods were used to measure the associations between spatial access to health care and ACSC rates of both inpatient hospitalizations and ED visits. Results Spatial access to primary care has a statistically significant positive relationship with both rates of inpatient hospitalization admissions and ED visits for ACSCs for the elderly. Spatial access to hospitals has a statistically significant negative relationship with both rates. Spatial access to primary care has a significantly negative contribution to the likelihood of inpatient hospitalizations compared with the likelihood of ED visits for elderly ACSCs, whereas spatial access to hospitals has a significantly positive contribution. Conclusions Spatial access to health care contributes to elderly ACSC hospitalizations. A poorer access to primary care or a better access to hospitals increases both rates of inpatient hospitalizations and ED visits for elderly ACSCs. Seniors living in areas where residents had poor access to primary care or easy access to hospitals were more likely to visit EDs instead of being inpatients for ACSC conditions. Policy action is needed to improve spatial access to primary care for the elderly.
Generalization in multitask deep neural classifiers: a statistical physics approach.

A proper understanding of the striking generalization abilities of deep neural networks presents an enduring puzzle. Recently, there has been a growing body of numerically-grounded theoretical work that has contributed important insights to the theory of learning in deep neural nets. There has also been a recent interest in extending these analyses to understanding how multitask learning can further improve the generalization capacity of deep neural nets. These studies deal almost exclusively with regression tasks which are amenable to existing analytical techniques. We develop an analytic theory of the nonlinear dynamics of generalization of deep neural networks trained to solve classification tasks using softmax outputs and cross-entropy loss, addressing both single task and multitask settings. We do so by adapting techniques from the statistical physics of disordered systems, accounting for both finite size datasets and correlated outputs induced by the training dynamics. We discuss the validity of our theoretical results in comparison to a comprehensive suite of numerical experiments. Our analysis provides theoretical support for the intuition that the performance of multitask learning is determined by the noisiness of the tasks and how well their input features align with each other. Highly related, clean tasks benefit each other, whereas unrelated, clean tasks can be detrimental to individual task performance.
Gaining Recognition in the Community

Today, more than ever before, the new physician has the opportunity to carve and sculpt their practice using ethical marketing techniques. This chapter will focus on the new physician and how to grow and actually use marketing techniques to create an ideal practice.
“Beam us up, Bgwëthnėnė!” Indigenizing science (fiction):

The popularity of Indigenous-authored science fiction art, literature, film, and even video games has exploded in recent years. More than just a niche interest, these works have material effects on...
D1-S169A substitution of photosystem II reveals a novel S2-state structure.

Abstract In photosystem II (PSII), photosynthetic water oxidation occurs at the O2-evolving complex (OEC), a tetramanganese-calcium cluster that cycles through light-induced redox intermediates (S0–S4) to produce oxygen from two substrate water molecules. The OEC is surrounded by a hydrogen-bonded network of amino-acid residues that plays a crucial role in proton transfer and substrate water delivery. Previously, we found that D1-S169 was crucial for water oxidation and its mutation to alanine perturbed the hydrogen-bonding network. In this study, we demonstrate that the activation energy for the S2 to S1 transition of D1-S169A PSII is higher than wild-type PSII with a ~1.7–2.7× slower rate of charge recombination with QA− relative to wild-type PSII. Arrhenius analysis of the decay kinetics shows an Ea of 5.87 ± 1.15 kcal mol−1 for decay back to the S1 state, compared to 0.80 ± 0.13 kcal mol−1 for the wild-type S2 state. In addition, we find that ammonia does not affect the S2-state EPR signal, indicating that ammonia does not bind to the Mn cluster in D1-S169A PSII. Finally, a QM/MM analysis indicates that an additional water molecule binds to the Mn4 ion in place of an oxo ligand O5 in the S2 state of D1-S169A PSII. The altered S2 state of D1-S169A PSII provides insight into the S2➔S3 state transition.
Radiation driven Hohlraum using 2ω for ICF implosions at the NIF

Radiation flux symmetry in laser-irradiated Hohlraum environments is difficult to model and control and relies on the details of plasma evolution and laser energy deposition in the harsh plasma-filled Hohlraum over the duration of the laser pulse. This study presents a conceptual design and assesses the feasibility of using lasers to create a radiation drive where the implosion symmetry relies mainly on radiation transport. In this design, the ends of a capsule containing Hohlraum are irradiated by drive laser beams that are shielded from the view of the capsule. This configuration enables the use of frequency doubled light that has a higher power and energy threshold for the current capability of NIF, up to 670 TW and ∼3.5 MJ. We estimate, using VISRAD benchmarked against HYDRA calculations, that the same drive conditions that are currently being achieved in hybridE experiments at the NIF 270–290 at the equator can be reached in this new geometry and large 6.4 mm diameter Hohlraums. The radiation drive asymmetries in this design can be mitigated by shimming the capsule ablator thickness or through tailoring the shape of the shielding to the laser spots.
Canadian Federal Election and Hashtags that Do Not Belong

Topic modeling plays a central roll for understanding discussion on social media platforms such as Twitter. One simple, yet powerful, method of topic analysis on Twitter is performing community detection on the network of hashtags. While this approach is simple and scalable, its interpretability has room for improvement. From a community-detection perspective, some hashtags obscure topics more than they help define them. In this work, we introduce a method of filtering hashtags from topic groups to create more interpretable topics. This modularity-based approach is highly scalable, which we demonstrate through analysis of three networks with approximately one million nodes. These networks were collected the week before, during, and after the Canadian federal election of 2019. Our hashtag filtering method is demonstrated to improve the resulting topics, allowing for easier interpretation. From the resulting topics, it is shown that both liberals and conservatives led effective hashtag campaigns, and that discussion quickly moved away from specific parties and toward issues like climate change in the week following the election.
Site occupation of indium and jump frequencies of cadmium in FeGa 3

Perturbed angular correlation (PAC) measurements using the In-111 probe were carried out on FeGa3 as part of a broader investigation of indium site occupation and cadmium diffusion in intermetallic compounds. One PAC signal was observed with hyperfine parameters ω1= 513.8(1) Mrad/s and η= 0.939(2) at room temperature. By comparison with quadrupole frequencies observed in PAC measurements on isostructural RuIn3, it was determined that indium occupies only the 8j site in the FeGa3 structure, denoted Ga(2) below because two out of the three Ga sites have this point symmetry. PAC spectra at elevated temperature exhibited damping characteristic of electric field gradients (EFGs) that fluctuate as Cd probes jump among Ga(2) sites within the lifetime of the excited PAC level. A stochastic model for the EFG fluctuations based on four conceivable, single-step jump-pathways connecting one Ga(2) site to neighboring Ga(2) sites was developed and used to fit PAC spectra. The four pathways lead to two observable EFG reorientation rates, and these reorientation rates were found to be strongly dependent on EFG orientation. Calculations using density functional theory were used to reduce the number of unknowns in the model with respect to EFG orientation. This made it possible to determine with reasonable precision the total jump rate of Cd among Ga(2) sites that correspond to a change in mirror plane orientation of site-symmetry. This total jump rate was found to be thermally activated with an activation enthalpy of 1.8 ±0.1 eV.
X-ray Lithography

X-ray lithography is an important process used in the manufacture of high aspect ratio microstructures. It also represents a promising alternative to ultraviolet optical lithography in the manufacture of large scale integrated circuits with high resolution. The process involves the irradiation of a mask and a photoresist deposited on a substrate. A gas such as helium circulates in the gap between mask and resist as a cooling device. The mask is made of a thin membrane of low atomic weight material, through which x-rays can be transmitted readily, and a metallic absorbing pattern such as gold which has a high x-ray absorbing capability. The mask layer creates a desired pattern on the photoresist by selectively allowing the transmission of irradiation from an x-ray beam. Polymethylmethacrylate (PMMA) and other photoresists used in patterning microelectromechanical systems (MEMS) are poor conductors of heat compared to the supporting silicon substrate.
Refractive Error Findings in Students Who Failed School-based Vision Screening

To report refractive error findings in Baltimore City schoolchildren who failed school-based vision screenings.In this cross-sectional analysis, students pre-kindergarten through 8th grade who fail...
IRRIGATION DEVELOPMENT IN THE USSR DURING THE 10TH FIVE-YEAR PLAN (1976–1980)

Irrigation development in the 10th Five-Year Plan is a continuation of long-term Soviet efforts to improve agriculture in arid regions by supplementation of natural moisture supplies. Major emphasis is on expanding irrigation in Central Asia, the Ukraine, the North Caucasus and along the lower Volga. Serious problems continue to plague this economic sector: organizational inadequacies, an inefficient technology, and widespread secondary soil salinization. Serious efforts are being made to alleviate these difficulties in the 10th Five-Year Plan. The most critical future obstacle to expansion of irrigation may be a shortage of surface flow, necessitating more efficient irrigation practices, greater use of ground water, and ultimately large-scale interbasin river diversions.
Performance Assessment of Secondary-Roadway Infrastructure in Iowa after 2011 Missouri River Flooding

AbstractThe Missouri River flooding in 2011 caused significant damage to secondary roadway infrastructure systems in western Iowa. This paper documents results of an investigation designed to evaluate unpaved roads and bridge approaches in the flood-affected areas. In situ testing was conducted as flood waters receded and several months later to evaluate performance and recovery conditions. In situ tests included falling weight deflectometer, dynamic cone penetrometer, and ground penetrating radar scanning. Field results indicated statistically significant differences over time in roadway support characteristics between flooded and nonflooded areas. Support characteristics in some flooded areas did not recover over the duration of the research reported in this paper (7–8 months after flooding). Multivariate statistical analysis indicated that the dynamic composite stiffness of the flooded unpaved roads was highly dependent on the stiffness of the underlying subgrade layer. Voids were detected in culvert a...
Pulsed gate dielectric breakdown in a 32 nm technology under different ESD stress configurations

We report pulsed high-k gate dielectric breakdown in various configurations emulating ESD stress in real input/output circuits. The stress on the receiver is of greater concern than is stress on the driver due to different gate oxide areas under stress. Methods to improve pad voltage tolerance for gate oxide breakdown are proposed.
The corrected orthogonal electrocardiogram in normal children: McFee and Parungao lead system☆

Abstract Corrected orthogonal electrocardiograms, obtained by means of McFee and Parungao's lead system, were recorded from 100 normal children, ranging in age from 1 to 15 years. Data from the QRS complex were analyzed by means of a digital computer. The amplitudes and duration of the QRS deflections, as well as the curves of spatial magnitude, orientation, and velocity are presented. Correlations of the QRS amplitudes and MSM against age, weight, body surface area, and chest circumference demonstrate, in general, no significant relation-ship. A low, but statistically significant correlation was found between both the Q wave and the QR ratio in the Z lead; and body surface area, body weight, and age.
Quasitopological electromagnetic response of line-node semimetals

Topological semimetals are gapless states of matter which have robust surface states and characteristic electromagnetic responses. In this paper, we consider the electromagnetic response of gapless phases in $3+1$ dimensions with line nodes. We show through a layering approach that an intrinsic antisymmetric tensor ${\mathcal{B}}_{\ensuremath{\mu}\ensuremath{\nu}}$ (2-form), which is determined by the geometry and energy-embedding of the nodal lines, emerges in the effective response field theory. ${\mathcal{B}}_{\ensuremath{\mu}\ensuremath{\nu}}$ is shown to be simply related to the charge polarization and orbital magnetization of the sample; hence the geometry of the line nodes determines these electromagnetic observables. We conclude by discussing the relevance for recently proposed materials and heterostructures with line-node fermi-surfaces.
CHAPTER 18 – cDNA Synthesis

The synthesis of cDNA is a central, although technically challenging, component of the research involving molecular biology techniques. Chemically cDNA is identical to genomic DNA, and it is useful in both the single-stranded and double-stranded forms. Although the classical methods for cDNA propagation have given way to polymerase chain reaction (PCR), knowledge of the mechanics of traditional cDNA synthesis and its significance remain central to the proper understanding of the technology and interpretation of data. The cDNA is a product of enzymatic in vitro synthesis, one strand at a time, using RNA as template material. The need for high-quality RNA is the first and foremost requirement. The synthesis of cDNA confers a number of advantages to the investigator who wish to characterize gene structure or expression, develop nucleic acid probes, or express proteins that might otherwise be difficult to purify. First, RNA is a naturally labile single-stranded molecule, and its conversion into more stable double-stranded DNA facilitates long-term storage of these sequences. Second, by synthesizing and cloning the resulting cDNAs from a single source, the investigator creates a method for propagating the cDNA as needed. Generally, cDNA is synthesized directly from an RNA template; therefore, cDNAs present at the end of a synthesis reaction directly mirror the RNA complexity at the beginning of the synthesis reaction.
Disconnection modes for mobile databases

As mobility permeates into todays computing and communication arena, we envision application infrastructures that will increasingly rely on mobile technologies. Traditional database applications and information service applications will need to integrate mobile entities: people and computers. In this paper, we develop a distributed database framework for mobile environments. A key requirement in such an environment is to support frequent connection and disconnection of database sites. We present algorithms that implement this framework in an asynchronous system.
In vitro production of Clostridium perfringens enterotoxin and its detection by reversed passive hemagglutination.

The reversed passive hemagglutination (RPHA) test yielded a positive reaction in 2 h with as little as 0.5 ng of purified Clostridium perfringens enterotoxin (CPE) per ml as well as with cultures of some C. perfringens grown in Duncan-Strong (DS) medium. This method is the most sensitive, the simplest, and the fastest among all reported. The time course of CPE production of Clostridium perfringens NCTC 8798 in DS was investigated by RPHA. CPE in culture was detectable at 4 h, increased gradually, reached a maximum at 12 to 14 h, and remained at a high level of 20 μg/ml through 48 h of incubation. CPE synthesized within cells is released easily by sonic disruption of young cultures and by aging the cultures 20 h or more. Heat shock of the cell inoculum was essential for CPE production by C. perfringens in DS.
Asymptotic conditional probabilities for conjunctive queries

We study the asymptotic probabilities of conjunctive queries on random graphs.We consider a probabilistic model where the expected graph size remains constant independent of the number of vertices. While it has been known that a convergence law holds for conjunctive queries under this model, we focus on the calculation of conditional probabilities. This has direct applications to database problems like query-view security, i.e. evaluating the probability of a sensitive query given the knowledge of a set of published views. We prove that a convergence law holds for conditional probabilities of conjunctive queries and we give a procedure for calculating the conditional probabilities.
Reprojection and backprojection in SPECT image reconstruction

An algorithm compensating the deterministic effects of photon attenuation, scattering, and collimator divergence associated with quantitative SPECT (single-photon-emission computed tomography) images is presented. The compensation algorithm is based on a technique which traces the geometrical relations of pixels and projection rays. If the attenuation map of the source distribution and the collimator divergence function are known, the compensation is accurate. The implementation of the compensation algorithm within the reprojection processes is carried out in an iterative manner for computer-generated ideal data. Improvement in image reconstruction of SPECT is demonstrated. An analytical study of implementing the compensation algorithm, the backprojection process, is given. A Bayesian analysis is used to suppress the artifacts due to the low count detection of photons associated with SPECT. A comparison of the BIP (Bayesian image processing) and ML (maximum-likelihood) methods on image reconstruction is carried out for computer-generated ideal and Poisson randomized data. Improved images using the BIP method are obtained. >
Insulation Levels of DC Filter Reactors and Resistors for HVDC Power Transmission

This paper concerns the insulation of reactors and resistors in the harmonic filter circuits on the dc side of an HVDC converter station. The cost of these reactors and resistors is greatly dependent on their insulation levels, and could be a substantial part of the total filter costs if their insulation levels are comparable to the insulation level of the dc busbars.
A study of turbulent combustion and its modeling using a diffusion reaction equation model

An enhanced diffusion-reaction system (DRS) is proposed as a statistical model for the evolution of multiple scalars undergoing mixing and reaction in an isotropic turbulence field. The DRS model is close enough to the scalar equations in a reacting flow that other statistical models of turbulent mixing, which decouple the velocity field from scalar mixing and reaction (e.g. mapping closure model, assumed-pdf models), cannot ditinguish the model (DRS) equations from the exact equations. Numerical simulations of the DRS equations are performed for three scalars evolving from non-premixed initial conditions. A simple one-step reversible reaction is considered. The data from the simulations are used to (i) study the effect of chemical conversion on the evolution of scalar statistics, and (ii) evaluate other models (mapping-closure model, assumed multivariate β-pdf model) leading to inferences about engineering approaches to turbulent combustion modeling.
Rapid repeat pregnancy in adolescents: do immediate postpartum contraceptive implants make a difference?

Objective The purpose of this study was to determine contraceptive continuation and repeat pregnancy rates in adolescents who are offered immediate postpartum etonogestrel implant (IPI) insertion. Study Design Participants in an adolescent prenatal-postnatal program were enrolled in a prospective observational study of IPI insertion (IPI group, 171) vs other methods (control group, 225). Contraceptive continuation and repeat pregnancies were determined. Results Implant continuation at 6 months was 96.9% (156/161 participants); at 12 months, the continuation rate was 86.3% (132/153 participants). At 6 months, 9.9% of the control participants were pregnant (21/213); there were no IPI pregnancies. By 12 months, 18.6% of control participants (38/204) experienced pregnancy vs 2.6% of IPI recipients (4/153; relative risk, 5.0; 95% confidence interval [CI], 1.9–12.7). Repeat pregnancy at 12 months was predicted by not receiving IPI insertion (odds ratio, 8.0; 95% CI, 2.8–23.0) and having >1 child (odds ratio, 2.1; 95% CI, 1.1–4.3; P = .03). Conclusion IPI placement in adolescents has excellent continuation 1 year after delivery; rapid repeat pregnancy is significantly decreased compared with control participants.
A tale of two angels.

This commentary discusses the Office of Inspector General's recommendation that the Centers for Medicare&Medicaid Services (CMS) issue guidance concerning the documentation providers should keep to...
Using objective measures of stove use and indoor air quality to evaluate a cookstove intervention in rural Uganda

Abstract Exposure to combustion byproducts from cooking is a major health concern globally. Alternative stoves may reduce the burden of disease associated with exposure to household air pollution. We subsidized Ugastove-brand rocket stoves to 54 households in six rural Ugandan villages. We monitored kitchen concentrations of fine particles (PM 2.5 ) and carbon monoxide (CO) before and one month after introduction of the Ugastove. Temperature data-loggers were affixed to each Ugastove and to the traditional stove (three‐stone fire) during the 1-month Ugastove acclimation period to record temporal patterns in stove use and adoption. Household surveys were administered to collect household information that may impact stove use or indoor air quality. PM 2.5 kitchen concentrations were 37% lower after introduction of the Ugastove (mean reduction: 0.68 mg/m 3 ; 95% confidence interval [CI]: 0.2–1.2; p 2.5 concentrations were generally lowest in households that used primarily the Ugastove, followed by households that used stoves in tandem and that primarily used a three‐stone fire. In summary, introduction of the Ugastove in 54 rural Ugandan households was associated with modest reductions in kitchen concentrations of PM 2.5 but not CO. Objective measures of stove use reveal that short-term stove use varied by household.
The “July Effect” in Primary Total Hip and Knee Arthroplasty: Analysis of 21,434 Cases From the ACS-NSQIP Database

The "July effect" is the hypothetical increase in morbidity thought to be associated with the training of new residents during the first portion of the academic year. We evaluated for the presence of the July effect in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database among 21,434 patients who underwent primary total hip or knee arthroplasty. There was no association of an interaction term for academic quarter and resident involvement with "serious adverse events" (P = 0.656) or "any adverse events" (P = 0.578). As a result, this study could not demonstrate a July effect. Patients can be reassured that undergoing total joint arthroplasty during the first part of the academic year is without increased risk of adverse events related to the training of residents.
The morphological evolution of the Bi2Mo3O12(010) surface in air–H2O atmospheres

Abstract Atomic force microscopy (AFM) has been used to examine the morphological evolution of the Bi 2 Mo 3 O 12 (010) surface at 400–600 °C in dry air and air–2.3% H 2 O. The (010) cleavage surface is characterized by atomically flat terraces separated by straight steps that are integer multiples of b /2 (5.75 A) in height. During treatments at or above 500 °C, the surface is etched due to the volatilization of Mo. In dry air, etching affects both steps and flat terraces and results in step recession, the development of half-unit-cell ( b /2) step loops (pits and islands), and the accumulation of Bi-rich surface deposits. In air–2.3% H 2 O, steps are etched with preference to terraces, and this leads to step recession as well as the formation of Bi-rich deposits. Mo volatilization proceeds at an enhanced rate in air–2.3% H 2 O and culminates in the nucleation and growth of Bi 2 MoO 6 and Bi 2 Mo 2 O 9 precipitates at 500 and 600 °C, respectively.
Kinetics of neutrophil production following filgrastim sd/01

Abstract Filgrastim SD/01 is a new form of Filgrastim (r-metHuG-CSF) with sustained effective duration in vivo (Molineux et al. Exp Hemat 27,1999,1724). We have compared its ability with that of conventional Filgrastim to stimulate neutrophilia in normal and leukopenic mice. We have also measured the kinetics of neutrophil production in normal mice following stimulation with SD/01. SD/01 (1 g/kg) was injected iv to normal mice 3 d after injection of cyclophosphamide (200 mg/kg), and temozolamide (90 mg/kg). Subsequent WBCC and neutrophils were recorded daily. Conventional filgrastim was injected 2 × daily (125 mg/kg) for 3 d. For production kinetics, normal mice were injected with tritiated thymidine ( 3 HTdR, 37KBq/g) 3 d after SD/01. Bone marrow cytospins (@ 1 h) and blood smears (@ 1 h to 7 d later) were autoradiographed. Differential cell and 3 HTdR labelling indices were then counted. In normal mice, neutrophil counts increased 16 fold over 4 d. In leukopenic mice they increased from their 3 d nadir of 10 5 /ml to 26 × 10 6 /ml 4 d later. 3 HTdR labelling of maturing granulocytic cells in the marrow was 50–100% higher than in non-stimulated mice. Labelled mature neutrophils peaked in the peripheral blood 24 h (compared to 3-4 d in normal animals) after injection of 3 HTdR. Stimulation of neutrophil production by a single inoculum of SD/01 mirrors that of conventional G-CSF for which repeated injections over at least 3 d are necessary to maintain effective plasma levels. Analysis of the kinetics of granulocyte production shows accelerated proliferation in the marrow followed by rapid release into the peripheral blood of neutrophils with a normal peripheral half-life. We conclude that granulocytopoiesis is modulated by SD/01 in exactly the same way as the conventional formulation, and is considerably more manageable in its application.
Ambition-Limited, Problem-Focused Brief Marital Therapy.

Abstract In this atheoretical therapy model, treatment is limited to six to eight sessions and focuses on special problems raised by the couple and on the couple's capacity to react positively to clinical suggestions. Each partner is asked to state separately their commitment to the marriage and to justify the single quality or behavioral change that would be necessary to make the marriage acceptable to them. The partners meet separately with the therapist for one session and then select one essential issue to work on in therapy. Highlights of this therapy model include homework assignments, negotiation of conflict issues, communication training, and free expression of feelings.
High-Affinity Maltose Binding and Transport by the Thermophilic Anaerobe Thermoanaerobacter ethanolicus 39E

Thermoanaerobacter ethanolicus is a gram-positive thermophile that produces considerable amounts of ethanol from soluble sugars and polymeric substrates, including starch. Growth on maltose, a product of starch hydrolysis, was associated with the production of a prominent membrane-associated protein that had an apparent molecular weight of 43,800 and was not detected in cells grown on xylose or glucose. Filter-binding assays revealed that cell membranes bound maltose with high affinity. Metabolic labeling of T. ethanolicus maltose-grown cells with [(14)C]palmitic acid showed that this protein was posttranslationally acylated. A maltose-binding protein was purified by using an amylose resin affinity column, and the binding constant was 270 nM. Since maltase activity was found only in the cytosol of fractionated cells and unlabeled glucose did not compete with radiolabeled maltose for uptake in whole cells, it appeared that maltose was transported intact. In whole-cell transport assays, the affinity for maltose was approximately 40 nM. Maltotriose and alpha-trehalose competitively inhibited maltose uptake in transport assays, whereas glucose, cellobiose, and a range of disaccharides had little effect. Based on these results, it appears that T. ethanolicus possesses a high-affinity, ABC type transport system that is specific for maltose, maltotriose, and alpha-trehalose.
Dynamic modeling and forecasting on enterprise revenue with derived granularities

Timely and accurate forecasts are crucial in decision-making processes and have significant impacts on many business aspects. We at HP Labs have developed a complete set of quantitative forecasting methods that can enable the establishment of a reliable predictive reporting system, so that executives can discern as early as possible where the company is heading financially. This paper reports some of our technical developments in building such a predictive reporting system.
Effects of beliefs about the nature of knowledge on comprehension.

Two questions were addressed: «What are students' beliefs about the nature of knowledge?» and «How do these beliefs affect comprehension?»
Stability Of Perpendicular Domains In Thermomagnetic Recording Materials

The stability of reverse domains in thin films of magnetic materials having high coerciv-ity is investigated. It is shown that domains below a critical diameter are unstable and will collapse. To minimize this minimum domain diameter it is necessary to minimize domain wall energy while maximizing the product of magnetization times coercivity, M.Hc. Since M.Hc tends to be nearly a constant near the magnetic compensation temperature, it is concluded that domain wall energy a and the product M-Hcare critical parameters for assessing the use-fulness of a material for high density thermomagnetic recording applications.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
l-arginine availability regulates T-lymphocyte cell-cycle progression

l-arginine (l-Arg) plays a central role in several biologic systems including the regulation of T-cell function. l-Arg depletion by myeloid-derived suppressor cells producing arginase I is seen in patients with cancer inducing T-cell anergy. We studied how l-Arg starvation could regulate T-cell–cycle progression. Stimulated T cells cultured in the absence of l-Arg are arrested in the G0-G1phase of the cell cycle. This was associated with an inability of T cells to up-regulate cyclin D3 and cyclin-dependent kinase 4 (cdk4), but not cdk6, resulting in an impaired downstream signaling with a decreased phosphorylation of Rb protein and a low expression and binding of E2F1. Silencing of cyclin D3 reproduced the cell cycle arrest caused by l-Arg starvation. The regulation of cyclin D3 and cdk4 by l-Arg starvation occurs at transcriptional and posttranscriptional levels. Signaling through GCN2 kinase is triggered during amino acid starvation. Experiments demonstrated that T cells from GCN2 knock-out mice did not show a decreased proliferation and were able to up-regulate cyclin D3 when cultured in the absence of l-Arg. These results contribute to the understanding of a central mechanism by which cancer and other diseases characterized by high arginase I production may cause T-cell dysfunction.