cssi/SciSciGPT-SciSciNet huggingface dataset:
Global Climate Change and the Electric Power Industry

Publisher Summary This chapter provides a brief description of global warming, which contributes to the unprecedented accumulation of CO2 and other greenhouse gases in the atmosphere. It concentrates on CO2, the principal greenhouse gas. Results from major studies are summarized to reveal the likely impacts of a continued increase of atmospheric CO2. It summarizes the limits imposed by current policies, by proposed legislation, and in scientific studies. It explains the potential for the electric power industry to play a pivotal role in the coming years. The industry could lead the way in cutting CO2 emissions during the 10–20 years following the adoption of mandatory carbon markets. The reduced emissions will come largely from a reduction in conventional coal-fired generation. The reduction in coal generation could be replaced by a combination of fuel-switching, demand reduction, and investment in renewable generating technologies that exist today. The warming of the atmosphere and the oceans has been attributed to the release of carbon dioxide and other greenhouse gases to the atmosphere. CO2 is the principal greenhouse gas, and the generation of electric power accounts for an important share of the CO2 emissions. Scientists and policymakers are calling for major reductions in CO2 emissions and debating a variety of policies to achieve the reductions. The policy options include a combination of targets, regulations, and financial incentives to “put a price on carbon.” That price could come from either a carbon tax or a carbon market, but policymakers are inclined to use carbon markets. The electricity sector is expected to play a leading role in cutting emissions when nations put a price on carbon.
A Single Nickel Catalyst for the Acceptorless Dehydrogenation of Alcohols and Hydrogenation of Carbonyl Compounds

A single homogeneous nickel(II) complex, supported by the tris(3,5-dimethylpyrazolyl)borate ligand and 2-hydroxyquinoline ancillary ligand, is shown to catalyze both acceptorless dehydrogenation of alcohols and hydrogenation of carbonyl compounds under mild conditions. Products from the catalytic reactions were isolated with good yields. A mechanistic investigation highlights the critical role of the 2-hydroxyquinoline ligand in the catalysis and argues against a stepwise dehydrogenation pathway.
Analytics for Knowledge Creation: Towards Epistemic Agency and Design-Mode Thinking

Innovation and knowledge creation call for high-level epistemic agency and design-mode thinking, two competencies beyond the traditional scopes of schooling. In this paper, we discuss the need for learning analytics to support these two competencies, and more broadly, the demand for education for innovation. We ground these arguments on a distinctive Knowledge Building pedagogy that treats education as a knowledge-creation enterprise. By critiquing current learning analytics for their focus on static-state knowledge and skills, we argue for agency-driven, choice-based analytics more attuned to higher order competencies in innovation. We further describe ongoing learning analytics initiatives that attend to these elements of design. Prospects and challenges are discussed, as well as broader issues regarding analytics for higher order competencies.
Growing programs: an agile alternative to stepwise refinement

The use of pseudocode in teaching algorithmic problem solving and program design has proven a difficult barrier for many CS1 students. The evidence of several, independent studies suggests that many students have great difficulty in using it to develop a new algorithm, and when they do, they often produce logical inconsistencies in pseudocode, causing significant confusion at the point where they must produce concrete implementations of the parts.
How much pain relief do patients expect after cholecystectomy

Cholecystectomy is a common operation, increasingly performed, in the USA, for “functional gall bladder disorder” (FGBD). Outcomes of these surgeries are uncertain. In planning a study of FGBD, we needed to define the best outcome measures. We sought the opinions of patients (52 with FGBD and 100 with stones for comparison) coming to cholecystectomy. They were asked to respond in four ways about the minimum benefit they would count as “success.” We found that most patients do not expect cholecystectomy to relieve their pain-related disability completely, regardless of the presence or absence of stones. Future studies of the success of surgery should use patient-centered outcome assessments, such as PGIC (patient’s global impression of change), in addition to objective measures of the impact of treatment on key symptoms, such as pain.
Ventricular Tachycardia in the Setting of Chagasic Cardiomyopathy: Use of Voltage Mapping to Characterize Endoepicardial Nonischemic Scar Distribution.

Background Chagasic cardiomyopathy (CC) is the most frequent nonischemic substrate causing left ventricular (LV) tachycardia in Latin America. Systematic characterization of the LV epicardial/endocardial scar distribution and density in CC has not been performed. Additionally, the usefulness of unipolar endocardial electroanatomic mapping to identify epicardial scar has not been assessed in this setting. Methods and Results Nineteen patients with CC undergoing detailed epicardial and endocardial LV tachycardia mapping and ablation were included. A total of 8494 epicardial and 6331 endocardial voltage signals and 314 epicardial/endocardial matched pairs of points were analyzed. Basal lateral LV scar involvement was observed in 18 of 19 patients. Bipolar voltage mapping demonstrated larger epicardial than endocardial scar and core-dense (≤0.5 mV) scar areas (28 [20–36] versus 19 [15–26] and 21 [2–49] versus 4 [0–7] cm 2 ; P =0.049 and P =0.004, respectively). Bipolar epicardial and endocardial voltages within scar were low (0.4 [0.2–0.55] and 0.54 [0.33–0.87] mV, respectively) and confluent, indicating a dense/transmural scarring process in CC. The endocardial unipolar voltage value (with a newly proposed ≤4-mV cutoff) predicted the presence and extent of epicardial bipolar scar ( P Conclusions CC causes a unique ventricular tachycardia substrate concentrated to the basal lateral LV, with marked epicardial predominance. The scar pattern is particularly dense and transmural as compared with the more erratic/patchy scar patterns seen in other nonischemic cardiomyopathies. Endocardial unipolar voltage mapping serves to characterize epicardial scar in this setting.
The importance of land governance for biodiversity conservation in an era of global urban expansion

Abstract Mitigating the effects of urban expansion on habitat with high conservation value depends largely on national and sub-national governance that can effectively shape urban growth. This paper is the first study to map urban-caused biodiversity decline and governance. The central goal of this paper is to identify where and how weak governance and future urban expansion may combine to lead to the decline of biodiversity. We identify four categories of countries based on the level of biodiversity impact from urban expansion and governance capacity, as expressed in the Worldwide Governance Indicators. We review the literature of case studies to understand how governance capacity modulates the impact of urban expansion on biodiversity. Our results show that if predicted urban expansion continues, by 2030, more than two-thirds of all species impacted by urban expansion will occur in countries with low levels of political stability or regulatory quality, two factors which were identified as most important in the ability of land governance to mitigate urban threats on biodiversity. Our results suggest that land-use planning cannot be the sole solution for preventing urban-caused global biodiversity decline, but rather that different categories of countries need contrasting conservation strategies. Countries that have high potential biodiversity impact and low land governance capacity require short-term conservation strategies which facilitate public participation, as well as international aid and development to increase governance capacity. Furthermore, enhanced coordination across different decision-making levels is important so that strategies at a single scale do not counterbalance efforts at other levels.
Structure and Applications of Point Form Relativistic Quantum Mechanics

The framework of point form relativistic quantum mechanics is used to construct mass and current operators for hadronic systems with finite degree of freedom. For the point form all of the interactions are in the four-momentum operator and, since Lorentz transformations are kinematic, the theory is manifestly covariant.
Orthotic correction of sitting abnormality in achondroplastic children.

The spine of the achondroplastic child is poorly structured for weight-bearing (1, 2): 1. because the pedicles of the vertebrae are shortened, the distance between the two facet joints and between the facet joints and the vertebral body are less than normal. An abnormally narrowed and shortened weight-bearing structure results; 2. the ligamentous support of the spine is also affected adversely, for laxity of ligaments is among the characteristics of achondroplasia; 3. shortened ribs compound the problems of maintaining an erect trunk by reducing the bracing against flexion of the thoracic spine which longer ribs normally provide.
The Fossil Record: Tracing the Roots of the Cyanobacterial Lineage

Since the mid-1960s, following a century of unrewarded search, impressive progress has been made toward deciphering the Precambrian fossil record, evidence of life extant during the earliest seven-eighths of geologic time. Hundreds of fossiliferous units have been discovered containing thousands of microbial fossils—dominantly but not exclusively cyanobacterial — and the documented antiquity of life has been extended to an age roughly three-quarters that of the Earth. Mutually reinforcing lines of evidence, paleontological, geological, and isotopic geochemical, indicate that stromatoliticmicrobial ecosystems,evidently including cyanobacteria and other members of the bacterial domain, were extant ~3500 Ma ago; methanogenic archaeans by ~2800 Ma ago; and Gram-negative sulfate-reducing bacteria at least as early as ~2700 Ma ago.The discrepancy between these dates and those suggested for emergence of these groups by a recently proposed amino acid-based “molecular clock” is too great and too consistent to be ignored. The challengeis to unify the molecular data with the increasingly well-established paleobiologicrecord.
Improved detection of hepatic metastases with contrast-enhanced low mechanical-index pulse inversion ultrasonography during the liver-specific phase of sonazoid: observer performance study with JAFROC analysis.

Rationale and Objectives To compare B-mode ultrasonography (US) alone with the combination of B-mode and contrast-enhanced (Sonazoid) late-phase pulse-inversion US for the detection of hepatic metastases by use of jackknife free-response receiver-operating characteristic (JAFROC) analysis. Materials and Methods Twenty-seven patients with 57 hepatic metastases and 6 patients without hepatic metastases underwent B-mode and contrast-enhanced US. We used the diagnoses established by contrast-enhanced computed tomography and contrast-enhanced US as the standard of reference. All ultrasonographic scanning was performed by an experienced radiologist with a routine clinical procedure. All scanning data were archived with digital cine clips. A review system, which can display pairs of cine clips for B-mode and contrast-enhanced US side by side, was developed for off-site observer study. Seven radiologists interpreted each case individually first by B-mode US only, and then by the combination with contrast-enhanced US by identifying locations of possible candidates for hepatic metastasis with their confidence ratings. The figure-of-merit (FOM) values, sensitivity, and false-positives per case were estimated for B-mode US alone, and for the combination of B-mode and contrast-enhanced US. Results The sensitivities of the combined ultrasonographic imaging (mean, 72.2%) were clearly improved from that of B-mode US alone (mean, 41.6%) while reducing the average number of false positives from 1.1 to 0.5 per case. In the jackknife analysis, there was a statistically significant difference between mean FOM values for the combined imaging (0.76) and for B-mode US alone (0.44, P Conclusion Evaluating cine clips of contrast-enhanced liver US together with B-mode US could improve physicians' accuracy for detection of hepatic metastases.
Rehabbed to Death.

Rehabbed to Death For a substantial minority of older adults, a stay in a post-acute care facility is the gateway into a cycle between the hospital and the nursing home that spans the final months ...
Impulsive Loading Noise of a Lift-Offset Coaxial Rotor in High-Speed Forward Flight

This study was conducted to investigate the impulsive acoustic characteristics of a lift-offset coaxial rotor in high-speed forward flight, as well as the impact of wake-grid resolution and turbule...
A Novel Maximum Efficiency Point Tracking Technique for Modular Paralleled Electric Vehicle Charging System

It is well-known that the electric vehicle is the main trend for the future transportation market. Obviously, fast charging for the EV battery is the urgent and critical requirement of customers which makes the high output power chargers to be the mainstream products. Modular paralleled system is a good option to extend the charging system’s power and shorten the development cycle at the same time. The traditional current sharing method cannot optimize the system’s efficiency. In this paper, a novel maximum efficiency point tracking technique is proposed to improve the efficiency for modular paralleled power system at the light load (20%~50% load) and balance the accumulative operation energy for each module as well. Both the simulation and experiment results are given to show that the average efficiency improvement reaches 1.3%.
Cosmogenic 10Be exposure dating of Bull Lake and Pinedale moraine sequences in the upper Arkansas River valley, Colorado Rocky Mountains, USA

Many formerly glaciated valleys in the western United States preserve detailed glacial features that span the penultimate glaciation through the last deglaciation; however, numerical age control is limited in many of these systems. We report 35 new cosmogenic 10Be surface exposure ages of moraine boulders in the Sawatch Range, Colorado. Eight ages suggest Bull Lake moraines in Lake Creek (range: 132–120 ka, n = 4) and Clear Creek (range: 187–133 ka, n = 4) valleys may correlate with Marine Isotope Stage 6. In Lake Creek valley, 22 10Be ages from Pinedale end moraines average 20.6 ± 0.6 ka, and 5 10Be ages from a recessional moraine average 15.6 ± 0.7 ka, indicating that glaciers occupied two extended positions at ~21–20 and ~16 ka. The glacial extent dated to ~16 ka was nearly as great as that of the earlier glacial phase, suggesting that climate conditions in the Colorado Rocky Mountains at this time were similar to those of the last glacial maximum. Combining these moraine ages with seven previously published 10Be ages from cirque and valley-bottom bedrock reveals that the Lake Creek paleoglacier lost 82% of its full glacial length in ~1.5 ka and was completely deglaciated by ~14 ka.
Patterned rotary parallel-plate capacitor for frequency up-conversion and RC circuit waveform conditioning

This paper details a patterned electrostatic rotary capacitive plate design with high energy densities and provides a novel strategy for up-converting low frequency mechanical excitation sources. The rotating plates allow for output waveform signal conditioning in both control of frequency and waveform shaping. Particular advantages of the rotary plate design with patterned elements include the following: 1) simplicity of design, 2) frequency up-conversion, 3) output waveform signal conditioning, and 4) voltages appropriate for microelectronics. Applications include harvesting energy from environments with complex excitations, especially energy sources with inherently low-frequencies.
Novel low-cost neutron and gamma radiation detector

Abstract There is a desire from the radiation detection community to develop a low-cost method to detect neutron radiation. One potential solution is to measure the 478 keV gamma-ray from the 10B(n, α ) reaction using a spectroscopic gamma-ray detector. Experiments and Monte Carlo N-Particle 6.2 radiation transport simulations were performed for a NaI(Tl) detector surrounded with natural isotopic composition boron carbide powder. The neutron source for the experimental measurements was 241Am–Be.​ Additional MCNP simulations were performed using a 240Pu spontaneous fission neutron source. The experimental results were compared against 3He based measurements and found to be 70% as efficient as the 3He system. The total cost of this modification to an existing NaI(Tl) detector was $65.12. The optimal 10B-NaI(Tl) system design when measuring 240Pu was determined to consist of a 0.5 cm endcap of boron carbide and 6 cm of high-density polyethylene for neutron moderation.
Central Pacific hydroclimate over the last 45,000 years: Molecular-isotopic evidence from leaf wax in a Hawaiʻi peatland

Abstract Long-term hydroclimate variability at low latitudes exerts a strong influence on global climate, yet its timing and mechanisms are poorly documented for the central Pacific region. Here we present the molecular and hydrogen isotopic compositions of long-chain n-alkanes in a montane wetland deposit at Mount Kaʻala on the Island of Oʻahu, Hawaiʻi, which document hydrological conditions and related vegetation changes over the late Pleistocene and the Holocene. To aid the interpretation of fossil n-alkanes, we also determine chain-length distributions of the most common bog plants growing locally. Organic matter accumulation started around 45 ka BP, one of the oldest reported dates for peat-forming wetland ecosystems in Hawaiʻi. Sedimentary n-alkane distributions suggest vegetation shifts driven by changes in rainfall regime, especially with enhanced abundances of shorter chain length homologues during wet periods. Depleted values of n-alkane δ2H dated to ca 45–40, 24–22.5, 19–16.5, and 10–6 ka BP generally coincide with faster carbon accumulation rates, and may indicate enhanced winter cyclonic storm precipitation, as suggested by modern rainwater isotope data. For the Late Pleistocene, the consistency in timing and direction of hydroclimate variability at Kaʻala, dynamics of the Mauna Kea ice cap, precipitation in the Cariaco basin, and East Asian monsoon intensity suggest that southward shifts in the mean position of the ITCZ contributed to a greater frequency of extratropical cyclonic storms, increasing precipitation at leeward and high-elevation sites. During the Holocene, the ITCZ-hydroclimate linkage at Kaʻala is inverted, consistent with a Pacific dominated by ENSO variability.
Evaluating the impact of coronavirus disease 2019 on asthma morbidity: A comprehensive analysis of potential influencing factors.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic period is experiencing better asthma control, fewer exacerbations, and health care utilization, with limited data on factors that could explain this phenomenon. OBJECTIVE: To confirm these improved asthma outcomes during COVID-19 and evaluate potential contributing factors. METHODS: In 18,912 pediatric patients with asthma treated in the Children's Hospital of Orange County network from 2017 to 2020, monthly asthma-related encounters and medication summaries were extracted from electronic health records, particulate matter 2.5 (PM2.5) air pollution from the California Air Resources Board, and influenza-like illness from Illness Surveillance Network for the first 6 months of each year. Changes in outcomes between January to March and April to June (post-COVID-19 shutdown in 2020) were compared with historical data using generalized estimating equations analyses for patient outcomes and generalized linear models for pollution exceedance, influenza-positive, and telehealth visit rates. RESULTS: During COVID-19, we found 78%, 90%, 68% reductions in hospitalization, emergency department visits, and exacerbations, respectively, compared with pre-COVID-19 2020, with significantly greater changes than the same time period of 2017 to 2019 and significant reductions in albuterol and inhaled corticosteroid use (P < .05). Emergency department visit reduction was not seen for African Americans. The PM2.5 and influenza rates were also significantly reduced during COVID-19 (P < .05). Increased rates in telehealth visits were greater in the publicly insured group when compared with commercially insured. CONCLUSION: Our data confirm reduced health care utilization and suggest better asthma control during COVID-19, except for African Americans. This was associated with a significant increase in telehealth visits and reductions in PM2.5 and influenza infections, but not better asthma controller adherence.
Cantos, Carte, and Columns: A Hypothesis Concerning the Original Mise-en-page of Dante’s Comedy

John Ahern conjectures that, in writing out the first copies of the Comedy, Dante wrote on pages formatted for four 36-line columns, with two columns on each side of the page, and he assigned one page to each of the 100 cantos. Building on Ahern’s conjecture, the article suggests that Dante had a standard method of distributing the lines of a canto over the four columns. After describing the method, the article argues that Dante sometimes adapted his composition of a canto to the four-column page format, and that traces of this adaptation can be discerned in certain passages of the Comed
63438 Differential chromatin accessibility at dorsal root ganglia enhancers is associated with nerve injury

ABSTRACT IMPACT: Our improved understanding of the changes in chromatin accessibility that occur in persistent pain states may identify regulatory genomic elements that play essential roles in modulating gene expression in the DRG. OBJECTIVES/GOALS: Efforts to understand genetic variability involved in an individual’s susceptibility to persistent pain support a role for upstream regulation by epigenetic mechanisms. Our objective was to examine the transcriptomic and epigenetic basis of persistent pain following nerve injury. METHODS/STUDY POPULATION: We used a multiomic approach to identify novel molecular pathways associated with nerve injury-induced pain hypersensitivity. Adult Sprague Dawley rats were randomized to Chronic Constriction Injury (CCI) to the sciatic nerve or no treatment (naive). The ipsilateral L4-L6 dorsal root ganglia (DRG)s were removed on Day 14 and used for ChIP-seq for H3K4me1, ATAC-seq, and RNA-seq. We assessed for differential chromatin accessibility, transcription factor motifs, and enrichment for biological processes in chromatin accessible regions associated with cis-regulatory regions identified by ATAC-seq and H3K4me1 enrichment. Luciferase assays determined the functional significance of these sequences. RESULTS/ANTICIPATED RESULTS: We identified 58,446 genomic regions where H3K4me1 enrichment overlapped with chromatin accessibility. Differential analysis identified 2145 of these 58,446 regions that had changes in accessibility after CCI. The majority of these regions were located in introns or intergenic regions. Functional annotation of the differentially accessible regions identified disparate molecular functions enriched following nerve injury which suggests that altered chromatin structure plays a role in the development of mechanical hypersensitivity. Motif analysis identified specific transcription factor families whose binding sequences were enriched in regions of increased or decreased accessibility. Luciferase assays showed significant enhancement or repression of gene transcription. DISCUSSION/SIGNIFICANCE OF FINDINGS: Our data provides a comprehensive map of chromatin accessibility changes in the DRG after CCI and emphasizes the importance of chromatin structure in the development and maintenance of chronic pain.
The Natural Stage: Fanny Kemble's Journal of a Residence on a Georgian Plantation in 1838–1839

Noted British actress Fanny Kemble lived eighty-four years on and off the theatrical and political stages of the nineteenth century. Kemble was an active writer who authored her first five-act play, Francis the First, at the age of eighteen. She would go on to write at least ten other published works, including a second full-length play, multiple journals recording her personal observations, notes on Shakespeare, and poetry collections. While Kemble remained devoted to writing as personal practice throughout her life, her most well-known piece of writing is her 1863 Journal of a Residence on a Georgian Plantation in 1838–1839. Kemble's journal documents her outrage and disgust at the living conditions, harsh daily existence, and enslaved individuals she encountered while living on the two Sea Island plantations that her husband, Pierce Butler, inherited off the coast of Georgia.
Changes in Caries Experience, Untreated Caries, Sealant Prevalence, and Preventive Behavior Among Third-Graders in New York State, 2002-2004 and 2009-2012.

OBJECTIVE This study assessed changes in caries experience, untreated caries, sealant prevalence, and preventive behavior among third-grade children in New York State to monitor progress toward state health objectives. METHODS We analyzed children's data from the 2002-2004 (n=10,865) and 2009-2012 (n=6,758) New York State Oral Health Survey. We calculated differences in weighted percentages and 95% confidence intervals for caries experience, untreated caries, sealant prevalence, and preventive behavior. We used logistic regression procedures to assess the independent effects and interaction terms on dental caries experience. RESULTS The percentage of children with dental caries and untreated caries decreased from 54.1% and 33.0% in 2002-2004 to 45.2% and 23.6% in 2009-2012, respectively. While this decrease was not uniform across income subgroups, the prevalence of sealants, a key measure of the use of preventive services, increased significantly from 16.7% to 36.0% among lower-income children. CONCLUSIONS Measurable improvement in reducing dental caries prevalence among third-grade children has been made in New York State, but this improvement was not uniform across subgroups. Specifically, disease prevalence among lower-income children remained high, underscoring the need to strengthen existing programs and identify additional policy and programmatic interventions.
Working in Research Teams: Lessons from Personal Experiences

Managing a successful research team involves a variety of activities and potential issues. In this article, we discuss these issues based on our experience of having worked together for 20 years with regular team meetings that include Ph.D. and undergraduate students and occasionally other faculty colleagues. We attempt to describe the challenges that occur, including some ethical issues, and distil the knowledge we have gained over the years. We pose and answer nine questions about our team processes and procedures and end with a brief summary of key learning.
Analyzing Argumentation In Rich, Natural Contexts

The paper presents the theoretical and methodological aspects of research on the development of argument- ation in elementary school children. It presents a theoretical framework detailing psychological mechanisms responsible for the acquisition and transfer of argumentative discourse and demonstrates several applications of the framework, described in sufficient detail to guide future empirical investigations of oral, written, individual, or group argumentation performance. Software programs capable of facilitating data analysis are identified and their uses illustrated. The analytic schemes can be used to analyze large amounts of verbal data with reasonable precision and efficiency. The conclusion addresses more generally the challenges for and possibilities of empirical study of the development of argumentation.
Drag (linguistically defined)

In linguistics, “drag” generally refers to the use of language to perform an identity that the speaker does not claim as his or her own. As a performance, the language of drag performances differs from the changes associated with adopting a different social identity. Although “drag” is most commonly used to refer to gendered language use, it has also been used to refer to other types of performed identity. Keywords: crossing; drag; language
Use of discrete choice models with recommender systems

Recommender systems, also known as personalization systems, are a popular technique for reducing information overload and finding items that are of interest to the user. Increasingly, people are turning to these systems to help them find the information that is most valuable to them. A variety of techniques have been proposed for performing recommendation, including content-based, collaborative, knowledge-based and other techniques. All of the known recommendation techniques have strengths and weaknesses, and many researchers have chosen to combine techniques in different ways. In this dissertation, we investigate the use of discrete choice models as a radically new technique for giving personalized recommendations. Discrete choice modeling allows the integration of item and user specific data as well as contextual information that may be crucial in some applications. By giving a general multidimensional model that depends on a range of inputs, discrete choice subsumes other techniques used in the literature. We present a software package that allows the adaptation of generalized discrete choice models to the recommendation task. Using a generalized framework that integrates recent advances and extensions of discrete choice allows the estimation of complex models that give a realistic representation of the behavior inherent in the choice process, and consequently a better understanding of behavior and improvements in predictions. Statistical learning, an important part of personalization, is realized using Bayesian procedures to update the model as more observations are collected. As a test bed for investigating the effectiveness of this approach, we explore the application of discrete choice as a solution to the problem of recommending academic courses to students. The goal is to facilitate the course selection task by recommending subjects that would satisfy students' personal preferences and suit their abilities and interests. A generalized mixed logit model is used to analyze survey and course evaluation data. The resulting model identifies factors that make an academic subject “recommendable”. It is used as the backbone for the recommender system application. The dissertation finally presents the software architecture of this system to highlight the software package's adaptability and extensibility to other applications. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)
Novel Structural Determinants of μ-Conotoxin (GIIIB) Block in Rat Skeletal Muscle (μ1) Na+ Channels

mu-Conotoxin (mu-CTX) specifically occludes the pore of voltage-dependent Na(+) channels. In the rat skeletal muscle Na(+) channel (mu1), we examined the contribution of charged residues between the P loops and S6 in all four domains to mu-CTX block. Conversion of the negatively charged domain II (DII) residues Asp-762 and Glu-765 to cysteine increased the IC(50) for mu-CTX block by approximately 100-fold (wild-type = 22.3 +/- 7.0 nm; D762C = 2558 +/- 250 nm; E765C = 2020 +/- 379 nm). Restoration or reversal of charge by external modification of the cysteine-substituted channels with methanethiosulfonate reagents (methanethiosulfonate ethylsulfonate (MTSES) and methanethiosulfonate ethylammonium (MTSEA)) did not affect mu-CTX block (D762C: IC(50, MTSEA+) = 2165.1 +/- 250 nm; IC(50, MTSES-) = 2753.5 +/- 456.9 nm; E765C: IC(50, MTSEA+) = 2200.1 +/- 550.3 nm; IC(50, MTSES-) = 3248.1 +/- 2011.9 nm) compared with their unmodified counterparts. In contrast, the charge-conserving mutations D762E (IC(50) = 21.9 +/- 4.3 nm) and E765D (IC(50) = 22.0 +/- 7.0 nm) preserved wild-type blocking behavior, whereas the charge reversal mutants D762K (IC(50) = 4139.9 +/- 687.9 nm) and E765K (IC(50) = 4202.7 +/- 1088.0 nm) destabilized mu-CTX block even further, suggesting a prominent electrostatic component of the interactions between these DII residues and mu-CTX. Kinetic analysis of mu-CTX block reveals that the changes in toxin sensitivity are largely due to accelerated toxin dissociation (k(off)) rates with little changes in association (k(on)) rates. We conclude that the acidic residues at positions 762 and 765 are key determinants of mu-CTX block, primarily by virtue of their negative charge. The inability of the bulky MTSES or MTSEA side chain to modify mu-CTX sensitivity places steric constraints on the sites of toxin interaction.
Cascaded coefficient number systems lead to FIR filters of striking computational efficiency

Multiplierless FIR filters (or other fixed linear combiners) are built as add/subtract networks operating on bit-shifted input data. Classically, the computational structure required is determined by simply expressing the coefficients in canonical-signed-digit (CSD) form. In this paper, expressing coefficients in a higher-radix number system instead results in a computational structure for a partial solution, one that reduces a large linear-combination problem to a smaller one. A well-chosen sequence of such number systems then leads to a cascade of these problem-reducing networks that together solve the original problem with remarkable overall computational efficiency, especially for larger filters. An example FIR filter with a real chirp impulse response 3000 samples in length (a matched filter for a pulse-compression radar) was easily realized with -95 dB rms approximation error using less than two add or subtract operations per coefficient. This is a reduction of approximately 60% relative to the usual CSD method.
Tibial baseplate positioning in robotic-assisted and conventional unicompartmental knee arthroplasty

This study compared tibial baseplate alignment (TBA) between robotic-arm-assisted (RAA) and conventional (CONV) unicompartmental knee arthroplasties (UKAs). We hypothesized that RAA would increase the percentage of implants within a predetermined safe zone (SZ). We identified 177 CONV and 87 RAA UKAs through our center's patient registry. Two individuals reviewed postoperative knee radiographs and determined TBA. Coronal baseplate positioning was more accurate (i.e., within the SZ) for RAA (2.6° ± 1.5° vs. 3.9° ± 2.4°, p < 0. 0001). Conversely, sagittal alignment was more accurate for CONV (4.9° ± 2.8° vs. 2.4° ± 1.6°, p < 0.0001). RAA was more precise in both planes (p < 0.0001). There was no difference in the percentage of implants within the SZ between the two groups (p = 1.0).
Cell Differentiation Is a Primary Growth Process in Developing Limbs of Artemia

The limb of the brine shrimp Artemia develops over a four-instar period when the protopod, endite, exopod, endopod, and epipod are defined and cell differentiation (change in cell shape) occurs. To understand the importance of cell differentiation in limb growth, development of the epidermis was studied in the first thoracopod of instar V-VIII larvae. Each region was established by instar V, and the larval epidermal cells developed into general epidermal (GEC), tendinal, setal, or transport cells by instar VI. Basal extensions of the GECs formed pillar structures. The epidermal cells decreased in height from 10 to 4 microm by instar VI. Increase in length and width resulted from both cell replication and expansion of the apical cell surface in differentiating cells. Growth occurred mainly by cell replication in instar V, whereas expansion of the cell surface in GEC and setae was the major growth process in instar VII. Increase in apical cell surface area occurred primarily by change in cell shape from columnar to squamous during instar V and by increase in total cell surface in subsequent instars. The results demonstrated that cell differentiation is a significant component of growth during limb development.
Elevated CO2 and O3t concentrations differentially affect selected groups of the fauna in temperate forest soils

Rising atmospheric CO2 concentrations may change soil fauna abundance. How increase of tropospheric ozone (O3t) concentration will modify these responses is still unknown. We have assessed independent and interactive effects of elevated [CO2] and [O3t] on selected groups of soil fauna. The experimental design is a factorial arrangement of elevated [CO2] and [O3t] treatments, applied using Free-Air CO2 Enrichment technology to 30 m diameter rings, with all treatments replicated three times. Within each ring, three communities were established consisting of: (1) trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera) (2) trembling aspen and sugar maple (Acer saccharum) and (3) trembling aspen. After 4 yr of stand development, soil fauna were extracted in each ring. Compared to the control, abundance of total soil fauna, Collembola and Acari decreased significantly under elevated [CO2] (−69, −79 and −70%, respectively). Abundance of Acari decreased significantly under elevated [O3t] (−47%). Soil fauna abundance was similar to the control under the combination of elevated [CO2+O3t]. The individual negative effects of elevated [CO2] and elevated [O3t] are negated upon exposure to both gases. We conclude that soil fauna communities will change under elevated [CO2] and elevated [O3t] in ways that cannot be predicted or explained from the exposure of ecosystems to each gas individually.
Nonreciprocal and Magnetically Scanned Leaky-Wave Antenna Using Coupled CRLH Lines

A new class of miniaturized nonreciprocal leaky-wave antenna (LWA) is proposed for wide angle scanning via magnetic tuning. A design is proposed based on coupled composite right left handed (CRLH) transmission lines (TLs) on a ferrite substrate for miniaturization with an external magnetic field control. Coupled TLs were previously utilized in a nonreciprocal LWA design with separate transmitter (TX) and receiver (RX) ports. In this work, CRLH TLs are employed to realize miniaturization, nonreciprocal properties and wide-angle scanning at the same time. To design the LWA, a circuit model was developed with the nonreciprocal propagation properties analytically calculated. For experimental validation, a 15-unit-cell prototype with a unit-cell length of only $\lambda _{0} /20$ was manufactured and tested. The TX and RX beams were independently scanned in the $E$ -plane up to 80 $^{\circ}$ by changing the bias field $\pm {50}~{\rm Oe}$ . The associated antenna gain varies between 3.5 and 5 dB at the operating frequency of 1.79 GHz as the beam is scanned. This is unlike traditional LWAs that achieve beamscanning via frequency control. Additionally, measured isolation between TX and RX ports was $\sim {10}~{\rm dB}$ .
The Sillon: An Experiment in Popular Education

The Sillon was founded a a mass political movement in 1899 by Marc Sangnier (1873-1950).Â Sangnier believed, however, that he could reach his goal only by educating the workers of the nation. In this article, Jefferson elaborates on the Sillon as an important education movement as well.
Toxicity and toxicokinetics of the cyclin-dependent kinase inhibitor AG-024322 in cynomolgus monkeys following intravenous infusion

Cyclin-dependent kinases (CDKs) play a significant role in the control of cell-cycle progression and exhibit aberrant regulation in various neoplastic diseases. AG-024322 is a potent inhibitor of CDK1, CDK2, and CDK4 that produces cell-cycle arrest and antitumor activity in preclinical models. This study evaluated the toxicity of AG-024322 when given by intravenous (IV) infusion to cynomolgus monkeys, including reversibility of effects. Male and female monkeys received AG-024322 by 30-min IV infusion once daily for 5 days at doses of 2, 6, and 10 mg/kg (24, 72, and 120 mg/m2, respectively). Controls received vehicle alone which was aqueous 5% dextrose, pH 3.8. Three animals/sex/group were necropsied on day 6, and two animals/sex/group at 6 and 10 mg/kg were necropsied on day 22 (reversal cohort). Doses were based upon the results of a dose range-finding study in monkeys; decreased white blood cells occurred at ≥3 mg/kg and 12 mg/kg produced central nervous system effects and was above the maximum-tolerated dose. No deaths occurred and clinical signs of toxicity, including swelling at the IV administration site, were seen at ≥6 mg/kg. AG-024322 at ≥6 mg/kg produced pancytic bone marrow hypocellularity, lymphoid depletion, and vascular injury at the injection site. Renal tubular degeneration occurred at 10 mg/kg. These changes were either reversible or in a process of repair following the 17-day recovery period. Hematology changes included decreases in reticulocytes and/or granulocytes at ≥6 mg/kg, which were reversible and consistent with changes in the bone marrow. Lymphoid and bone marrow depletion are consistent with pharmacologic inhibition of CDKs by AG-024322 and were expected findings. On day 22, vacuolar degeneration of pancreatic acinar cells with increased serum amylase and lipase levels occurred in one female at 10 mg/kg. Neither sex-related differences in toxicokinetics nor plasma accumulation over 5 days of dosing were seen. Terminal phase overall mean half-life on day 5 ranged from 6.69 to 8.87 h (across dose levels) and was not dose dependent. The no-adverse-effect dose of AG-024322 was 2 mg/kg and associated with overall mean plasma AUC(0–24.5) of 2.11 μg h/mL.
Anthropomorphic versus geometric chest phantoms: a comparison of scatter properties.

Previously, we have used an anthropomorphic chest phantom to study scatter reduction in digital chest radiography.Image metrics, such as scatter fractions, contrast, noise, and resolution, are not easily measured due to the anatomical structure in the phantom. A geometric chest phantom, recently developed for quality control purposes, offers the possibility of being used to calculate image quality measurements. Here, we compare the scatter properties of the two phantoms to determine if the geometric phantom can be used in our studies of scatter compensation techniques. A calibrated photostimulable phosphor system was used to acquire images of the two phantoms. An array of beam stops was placed in front of each phantom to calculate scatter fractions. Each phantom had approximately 2 in. of polystyrene material added to the posterior to increase scatter fractions to those normally seen in patients. Exposure parameters were 300 mA for 0.009 sec with a source to image distance of 100 cm. Energies were varied from 60 to 130 kVp. Scatter fractions were determined for different areas of anatomy for each energy and each phantom. For all energies examined, the two phantoms compare well for scatter fractions in each of six regions. For example, at 95 kVp, the geometric phantom had average scatter fractions of 0.72 and 0.88 in the lung and mediastinum regions, respectively. These values were 0.74 and 0.90 for the anatomic phantom. For comparison, measurements of scatter fractions in patients at these values have been reported as 0.65 and 0.90 for the lung and mediastinum regions. The geometric phantom is an excellent tool which can be used in place of the anthropomorphic phantom for studies involving scatter compensation. In addition to having a gray level histogram typical of a human chest, this phantom has uniform regions where image quality measurements can be calculated.
The National Security Agency's Senior Technical Development Program: A Clinical Psychologist's Experience

This article is based on material from the Presidential Address at the 2009 Society of Psychologists in Management Conference. It builds on an article (Civiello & Welker, 2009) that describes the National Security Agency (NSA) leadership model and the NSA Senior Technical Development Program (STDP). This article provides a practical example of how the STDP was applied for the development of the author as she respecialized as a counterintelligence psychologist. Her role as an embedded consultant is also discussed.
‘Don’, a Diploid Falcata Alfalfa for Western U.S. Rangelands

‘Don’ (Reg. No. CV-205, PI 655519), a diploid falcata alfalfa (Medicago sativa subsp falcata L.), was developed by the Forage and Range Research Laboratory in Logan, UT, in cooperation with the Utah Agricultural Experiment Station, Utah State University. Recent interest in falcata alfalfa has been high due to its value for increasing the productivity of rangelands. Don was selected for persistence under harsh conditions, uniform yellow fl ower color, increased seed production, and large-stature plants. Don traces to PI20725, an original collection made by N.E. Hansen in the Don Province of Russia. Don was tested as AU021. Don is signifi cantly more persistent than typical sativa (M. sativa Subsp sativa L.)–type alfalfas and is meant for use in mixed plantings with grasses either in range or pasture situations typical of the Intermountain region of the western United States. In comparative trials, including irrigated and nonirrigated, where 25 to 50% mortality was observed on sativa alfalfas, Don showed no mortality. When used in mixtures, the production advantage of Don with tall fescue [Schedonorus phoenix (Scop.) Holub; syn. Festuca arundinaceae Schreb.] and meadow brome (Bromus riparius Rehm.) ranged from 10 to 32% When Don is grown with crested wheatgrass on dry rangelands, similar production advantages are expected, which will make rangelands more productive. Furthermore, when grown in mixtures with grasses, Don will not dominate; rather, it has a low growth habit and stays well below the canopy of most cool-season grasses.
Accurate design of high-performance synchronous buck DC-DC power converters

Accurate power loss calculations are presented for a synchronous buck DC-DC power converter based on simple physics-based circuit models for the switch and inductor. The converter design is shown to be optimized for different die sizes of the high-side and low-side power switches; this design feature becomes important at increased switching frequencies. It is further shown that conventional power loss formulations are in error as they do not accurately calculate the switching power losses. A new figure-of-merit (FOM) is proposed to assess the performance of emerging high-performance power semiconductor switch technologies, especially for low-voltage point-of-load (POL) DC-DC power converters that utilize scaled silicon power MOSFETs and emerging Gallium Nitride (GaN) power transistors.
The solution of coupled Schrödinger equations using an extrapolation method

In this paper, extrapolation to the limit in a finite-difference method is applied to solve a system of coupled Schroedinger equations. This combination results in a method that only requires knowledge of the potential energy functions for the system. This numerical procedure has several distinct advantages over the more conventional methods. Namely, initial guesses for the term values are not needed; assumptions need be made about the behavior of the wavefunctions, such as the slope or magnitude in the nonclassical region; and the algorithm is easy to implement, has a firm mathematical foundation, and provides error estimates. Moreover, the method is less sensitive to round-off error than other methods since a small number of mesh points is used and it can be implemented on small computers. A comparison of the method with another numerical method shows results agreeing within 1 part in 10 exp 4.