cssi/SciSciGPT-SciSciNet huggingface dataset:
On the Cramér-Rao Bound of Time-Varying Narrowband Leaked MIMO OFDM Channels

In this paper, the problem of time-varying narrowband leaked Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) channel estimation is considered. Practical constraints on communication systems, e.g. finite bandwidth and block length cause leakage rendering a sparse channel into a non-sparse one. The current work extends prior work on single carrier and OFDM; herein, it is shown that leaked MIMO OFDM channel is also separable in the delay and Doppler domains. A convex optimization approach, based on the atomic norm heuristic and bilinear representation of the channel, is adapted for channel estimation. The Cramer-Rae Bound (CRB) on the leaked MIMO OFDM channel estimation is derived. Simulation results show superiority of the atomic norm-based bilinear channel estimator over the classical l 1 element-wise sparse method and an adaptive MIMO OFDM channel estimator; with an average 6.3 dB and 2 dB improvement, respectively. Comparison of the CRB with simulation, shows that the proposed algorithm is essentially optimal.
Democratizing Data Science through Interactive Curation of ML Pipelines

Statistical knowledge and domain expertise are key to extract actionable insights out of data, yet such skills rarely coexist together. In Machine Learning, high-quality results are only attainable via mindful data preprocessing, hyperparameter tuning and model selection. Domain experts are often overwhelmed by such complexity, de-facto inhibiting a wider adoption of ML techniques in other fields. Existing libraries that claim to solve this problem, still require well-trained practitioners. Those frameworks involve heavy data preparation steps and are often too slow for interactive feedback from the user, severely limiting the scope of such systems. In this paper we present Alpine Meadow, a first Interactive Automated Machine Learning tool. What makes our system unique is not only the focus on interactivity, but also the combined systemic and algorithmic design approach; on one hand we leverage ideas from query optimization, on the other we devise novel selection and pruning strategies combining cost-based Multi-Armed Bandits and Bayesian Optimization. We evaluate our system on over 300 datasets and compare against other AutoML tools, including the current NIPS winner, as well as expert solutions. Not only is Alpine Meadow able to significantly outperform the other AutoML systems while --- in contrast to the other systems --- providing interactive latencies, but also outperforms in 80% of the cases expert solutions over data sets we have never seen before.
Cyclin-dependent kinase inhibition: an opportunity to target protein-protein interactions

Abstract Cyclin-dependent kinases (CDKs) play an integral part in cellular activities. To date, most of the activities have been evaluated in the cell cycle and transcription. Several diseases are affected by abnormalities in CDKs, related-pathways, or proteins that regulate CDK activity. CDKs are primarily dependent on activation by binding other proteins, namely Cyclins. In addition, phosphorylation of key CDK residues also plays a major part in CDK activity. To date, the most successful drugs have been developed against CDK4 and CDK6 and are FDA approved for use in advanced breast cancer. However, this is likely only a small fraction of the potential for targeting CDKs as a strategy against cancer and other diseases. Based on the extensive protein-protein interactions made by CDKs with other proteins (Cyclins and others), there are numerous possibilities for targeting strategies against protein-protein interactions. Here we describe the predominant roles of CDKs in the cell, key interacting proteins, significant 3-dimensional structural characteristics, and summarize the work-to-date in inhibition of CDKs.
A development-in-sociocultural-context perspective on the multiple pathways to youth's engagement in learning

Abstract For three decades, motivation researchers have used the construct of engagement as a holistic lens for understanding how children interact with learning activities, highlighting that each child has a unique engagement profile comprised of behavioral, emotional/affective, cognitive, and social dimensions. As researchers continue to piece together the multifaceted nature of engagement, a pressing need has emerged for a synthetic, coherent review of the extant literature on engagement that clarifies its conceptualization, identifies its key facilitators and consequences, and delineates its functions. Using a developmental-contextual approach, this chapter presents an integrative theoretical perspective on engagement, emphasizing that engagement is the product of dynamic developmental and relational processes involving transactions across multiple ecologies. The integrative model of engagement offers a nuanced and comprehensive perspective on the multiple pathways—psychological, cognitive, and sociocultural—underlying the development of youth's engagement. The conceptualization and study of engagement as a multidimensional construct produced by an ongoing interaction between the individual and the environment informs the identification of the particular personal, contextual, and sociocultural factors that foster or undermine engagement, while increasing understanding of the psychosocial mechanisms through which the learning environment influences engagement.
Analysis of a female neonate with pyruvate dehydrogenase complex deficiency

Objective To analyze the clinical features and genetic basis of a female neonate with muscle weakness, abnormal brain magnetic resonance imaging and elevated blood lactate. Methods The patient was subjected to clinical and laboratory examination. Next generation sequencing was carried out for the patient and her relatives. Results The proband was diagnosed as small for gestational age, with clinical features including muscle weakness, abnormal brain magnetic resonance imaging, increased blood lactate, and acidosis. By genetic testing, a de novo PDHA1 mutation c. 1133G>A (p.R378H) was identified, which was known to be pathogenic. The patient was diagnosed with pyruvate dehydrogenase complex deficiency disease (PDCDD), for which vitamin B1, coenzyme Q10, and L-carnitine were prescribed, and a ketogenic diet was recommended. Follow-up at 4-month-7-day found that her blood lactic acid was reduced to normal but her muscle tone was still low. Conclusion The proband was diagnosed as PDCDD caused by a PDHA1 missense mutation. NGS has provided a powerful tool for the diagnosis of such diseases. Key words: Pyruvate dehydrogenase complex deficiency disease; PDHA1 gene; Next generation sequencing
Calcineurin-dependent regulation of endocytosis by a plasma membrane ubiquitin ligase adaptor, Rcr1

Rsp5, the Nedd4 family member in yeast, is an E3 ubiquitin ligase involved in numerous cellular processes, many of which require Rsp5 to interact with PY-motif containing adaptor proteins. Here, we show that two paralogous transmembrane Rsp5 adaptors, Rcr1 and Rcr2, are sorted to distinct cellular locations: Rcr1 is a plasma membrane (PM) protein, whereas Rcr2 is sorted to the vacuole. Rcr2 is delivered to the vacuole using ubiquitin as a sorting signal. Rcr1 is delivered to the PM by the exomer complex using a newly uncovered PM sorting motif. Further, we show that Rcr1, but not Rcr2, is up-regulated via the calcineurin/Crz1 signaling pathway. Upon exogenous calcium treatment, Rcr1 ubiquitinates and down-regulates the chitin synthase Chs3. We propose that the PM-anchored Rsp5/Rcr1 ubiquitin ligase-adaptor complex can provide an acute response to degrade unwanted proteins under stress conditions, thereby maintaining cell integrity.
Panel Testing for Hereditary Breast Cancer: More or Less?

Panel testing is increasingly being offered to patients. Currently, women may be offered a panel of up to 80 genes. Oncologists are tasked with understanding the indications for this testing as well as the potential implications. In this review, we outline which patients should undergo genetic testing for hereditary breast cancer, when this testing should be performed, and which genes should be tested for. Our understanding of hereditary breast cancer has drastically changed with the advent of next generation sequencing (NGS), and many additional genes have been associated with increased breast cancer risk. Some have advocated for genetic testing of all women with breast cancer. Routine genetic testing for all women with breast cancer is not warranted. Women with a phenotype associated with hereditary breast cancer, with a family history of cancer, or for whom a positive genetic test would change management should be offered genetic testing.
Incidence and characterization of fungal infections in chronic lymphocytic leukemia patients receiving ibrutinib.

Ibrutinib, a first-generation inhibitor of Bruton’s tyrosine kinase (BTK), is an important therapeutic option in chronic lymphocytic leukemia (CLL) [1]. In clinical trials, invasive fungal infectio...
55 Mn-based fiducial markers for rapid and automated RF coil localization for hyperpolarized 13 C MRI.

PURPOSE To use fiducial markers containing manganese 55 to rapidly localize carbon 13 (13 C) RF coils for correcting images for B1 variation. METHODS Hollow high-density polyethylene spheres were filled with 3M sodium permanganate and affixed to a rectangular 13 C-tuned RF coil. The relative positions of the markers and coil conductors were mapped using CT. Marker positions were measured by MRI using a series of 1D projections and automated peak detection. Once the coil location was determined, coil sensitivity was estimated using a quasi-static calculation. Simulations were performed to determine the minimum number of projections required for robust localization. Phantom experiments were used to confirm the accuracy of marker localization as well as the calculated coil sensitivity. Finally, in vivo validation was performed using hyperpolarized 13 C pyruvate in a rat model. RESULTS In simulations, our algorithm was accurate in determining marker positions when at least 6 projections were used (RMSE 1.4 ± 0.9 mm). These estimates were verified in phantom experiments, where markers locations were determined with an RMS accuracy of 1.3 mm. A minimum SNR of 4 was required for automated detection to perform accurately. Computed coil sensitivity had a median error of 17% when taken over the entire measured area and 5.7% over a central region. In a rat, correction for nonuniform reception and flip angle was able to normalize the signals arising from asymmetrically positioned kidneys. CONCLUSION Manganese 55 fiducial markers are an inexpensive and reliable method for rapidly localizing 13 C RF coils and correcting 13 C images for B1 variation without user intervention.
Statistical hyperbolicity of relatively hyperbolic groups

Statistical Hyperbolicity of Relatively Hyperbolic Groups by Jeremy Osborne The University of Wisconsin-Milwaukee, 2014 Under the Supervision of G. Christopher Hruska In this work, we begin by defining what it means for a group to be statistically hyperbolic. We then give several examples of groups, including non-elementary δhyperbolic groups, which either are statistically hyperbolic or are not. Following that, we define what it means for a group to be relatively hyperbolic. Finally, in the main portion of this work, we show that groups which are relatively hyperbolic, with a few additional conditions in place, must also be statistically hyperbolic.
A Framework for Linking Urban Traffic and Vehicle Emissions in Smart Cities

This paper tackles Challenge 4, ‘Computational Urban Data Analytics’, of the 2020 Smoky Mountains Conference Data Challenge. Specifically, we design and implement an analysis and visualization framework to study traffic emissions across time and space in a urban setting. We use our framework to qualitatively and quantitatively analyze the influence of urban layout on traffic flows in the Chicago Loop area. Our findings allow us to investigate the relationships between traffic congestion, building distributions, and vehicle emissions. Insights from our framework can provide communities with decision-making tools for urban design and smart cities.
Repurposing Domperidone in Secondary Progressive Multiple Sclerosis: A Simon 2-Stage Phase 2 Futility Trial.

Objective To assess whether treatment with the generic drug domperidone can reduce the progression of disability in secondary progressive multiple sclerosis (SPMS), we conducted a phase 2 futility trial following the Simon 2-stage design. Methods We enrolled patients in an open-label, Simon 2-stage, single-center, phase 2, single-arm futility trial at the Calgary Multiple Sclerosis Clinic if they met the following criteria: age of 18 to 60 years, SPMS, screening Expanded Disability Status Scale score of 4.0 to 6.5, and screening timed 25-ft walk (T25FW) of ≥9 seconds. Patients received domperidone 10 mg 4 times daily for 1 year. The primary outcome was worsening of disability, defined as worsening of the T25FW performance by ≥20% at 12 months compared to baseline. This trial is registered with ClinicalTrials.gov (NCT02308137). Results Between February 13, 2015, and January 3, 2020, 110 patients were screened, 81 received treatment, and 64 completed follow-up, of whom 62 were analyzed. The study did not meet its primary endpoint: 22 of 62 (35%) patients experienced significant worsening of disability, which is close to the expected proportion of 40% and above the predefined futility threshold. Patients with higher prolactin levels during the study had a significantly lower risk of disability progression, which may warrant further investigation. Domperidone treatment was reasonably well tolerated, but adverse events occurred in 84% and serious adverse events in 15% of patients. Conclusions Domperidone treatment could not reject futility in reducing disability progression in SPMS. The Simon 2-stage trial model may be a useful model for phase 2 studies in progressive MS. Trial Registration Information ClinicalTrials.gov Identifier: NCT02308137. Classification of Evidence This study provides Class III evidence that in individuals with SPMS participating in a futility trial, domperidone treatment could not reject futility in reducing disability progression at 12 months.
Cerebral Resuscitation and Traumatic and Hypoxic-Ischemic Brain Injury

The need for improved cerebral resuscitation was born out of progress – advancements in resuscitation, intensive care, and rehabilitation have decreased mortality associated with brain injury in infants and children, but increased the number living with disability. Indeed morbidity, and mortality for that matter, remains unacceptably high. To date, cerebral resuscitation after global ischemic injury due to cardiac arrest and traumatic brain injury (TBI) remains largely supportive, although many promising therapies are being explored at the bench and some at the bedside. This challenge to move innovative monitoring and therapies to the bedside to assist patients in attaining improved outcomes and quality of life has remained elusive. In the interim, optimizing patient care management in the prehospital setting, emergency department, pediatric intensive care unit (PICU), and rehabilitation facilities is our greatest opportunity for improving outcome in these pediatric patients.
A New Call to Action to Combat an Old Nemesis: Addressing Rising Congenital Syphilis Rates in the United States

Congenital syphilis (CS) is on the rise in the United States and is a growing public health concern. CS is an infection with Treponema pallidum in an infant or fetus, acquired via transplacental transmission when a pregnant woman has untreated or inadequately treated syphilis. Pregnant women with untreated syphilis are more likely to experience pregnancies complicated by stillbirth, prematurity, low birth weight, and early infant death, while their children can develop clinical manifestations of CS such as hepatosplenomegaly, bone abnormalities, developmental delays, and hearing loss. One of the ways CS can be prevented is by identifying and treating infected women during pregnancy with a benzathine penicillin G regimen that is both appropriate for the maternal stage of syphilis and initiated at least 30 days prior to delivery. In this article we discuss many of the challenges faced by both public health and healthcare systems with regards to this preventable infection, summarize missed opportunities for CS prevention, and provide practical solutions for future CS prevention strategies.
Measuring Critical Governance Sustainability at Various Levels: The Case of Bulgarian Agriculture

In Bulgaria, like in many other countries, practically there are no comprehensive assessments of the governance sustainability of agriculture and its importance for the overall agrarian development. This study tries to fill the gap and suggests a holistic framework for understanding and assessing the governance sustainability of Bulgarian agriculture. The newly elaborated approach is “tested” in a large-scale study for assessing the governance sustainability of country’s agriculture at national, sectoral, regional, ecosystem and farm levels. The study has proved that it is important to include the “missing” governance pillar in the assessment of the integral sustainability of agriculture and sustainability of agro-systems of various types. Multiple principles, criteria and indicators assessment of the governance sustainability of Bulgarian agriculture indicate that the overall governance sustainability is at a “good” but very close to the “satisfactory” level. Besides, there is a considerable differentiation in the level of integral governance sustainability of different agro-systems in the country. What is more, the individual indicators with the highest and lowest sustainability values determine the “critical” factors enhancing and deterring the particular and integral governance sustainability of evaluated agro-system. Last but not the least, results on the integral agrarian sustainability assessment based on micro (farm) and macro (statistical, etc.) data show some discrepancies which have to be taken into consideration in the analysis and interpretation, while assessment indicators, methods and data sources further improved.
The Brighter Side of Financial Risk: Financial Risk Tolerance and Wealth

Investors who accept a greater degree of financial risk expect to benefit from higher returns and greater wealth over time. This study explores the relationship between net worth and net financial assets and risk tolerance using data from the 1998 Survey of Consumer Finances. Willingness to take financial risk is associated with a significantly higher net worth for the whole sample, and for samples within age groups. Risk tolerance among those over 65 is among the strongest predictors of a higher net worth.
Gershwin: Rhapsody in Blue

The Rhapsody in Blue (1924) established Gershwin's reputation as a serious composer and has since become one of the most popular of all American concert works. In this richly informative guide David Schiff considers the piece as musical work, historical event and cultural document. He traces the history of the Rhapsody's composition, performance and reception, placing it within the context of American popular song and jazz and the development of modernism. He also provides a full account of the different published and recorded versions of the work and explores the many stylistic sources of Gershwin's music. The book also contains an extended discussion of Paul Whitman's Experiment in Modern Music, considers the influence of the Rhapsody on other works (e.g. the music of Duke Ellington) and examines the traditions and institutions of Jewish cultural populism.
Technologies for Turbofan Noise Reduction

An overview presentation of NASA's engine noise research since 1992 is given for subsonic commercial aircraft applications. Highlights are included from the Advanced Subsonic Technology (AST) Noise Reduction Program and the Quiet Aircraft Technology (QAT) project with emphasis on engine source noise reduction. Noise reduction goals for 10 EPNdB by 207 and 20 EPNdB by 2022 are reviewed. Fan and jet noise technologies are highlighted from the AST program including higher bypass ratio propulsion, scarf inlets, forward-swept fans, swept/leaned stators, chevron nozzles, noise prediction methods, and active noise control for fans. Source diagnostic tests for fans and jets that have been completed over the past few years are presented showing how new flow measurement methods such as Particle Image Velocimetry (PIV) have played a key role in understanding turbulence, the noise generation process, and how to improve noise prediction methods. Tests focused on source decomposition have helped identify which engine components need further noise reduction. The role of Computational AeroAcoustics (CAA) for fan noise prediction is presented. Advanced noise reduction methods such as Hershel-Quincke tubes and trailing edge blowing for fan noise that are currently being pursued n the QAT program are also presented. Highlights are shown form engine validation and flight demonstrations that were done in the late 1990's with Pratt & Whitney on their PW4098 engine and Honeywell on their TFE-731-60 engine. Finally, future propulsion configurations currently being studied that show promise towards meeting NASA's long term goal of 20 dB noise reduction are shown including a Dual Fan Engine concept on a Blended Wing Body aircraft.
Reactions Of Ammonia In Soils

Publisher Summary Use of ammonia as a source of nitrogen for agronomic application has become widespread in recent years. It is used as a gas, anhydrous ammonia, or in aqueous solutions sometimes containing other materials as well. Ammonia is also a product of microbial activity in soil. The fate of an ammonia molecule in the soil may be summed up as: it may be immediately chemically sorbed by the clay minerals or organic matter and it may be physically sorbed by the colloidal complex or dissolved in the soil moisture. From these temporary repositories, it may be eventually chemically sorbed or in the absence of available chemically reactive sites, may eventually diffuse through the soil pores to the surface and be lost to the atmosphere. The ability of a soil to react chemically with ammonia is most certainly related to its clay and organic matter contents. Information regarding the factors, which affect the utilization of ammonia chemically fixed by the organic matter, is needed for evaluating fully the availability of such reacted ammonia to plants.
Measuring copycat crime

Copycat crimes have not been identified or measured in a coherent manner. To forward the study of copycat crime, a methodology was developed to empirically score crimes that are suspected of being ...
The Rhetoric of Self and Other in Selected Iranian Short Stories, 1906-1979

The conflict that exists between the Western powers and Iran may seem a recent phenomenon, yet Iran's volatile perception of the West developed over several decades. The development of this perception is documented in six short stories written by the well-known Iranian writers Mohammad Ali Jamalzadeh, Bozorg 'Alavi, Sadeq Hedayat, Simin Daneshvar, Gholam-Hosain Sa'edi, and Jalal Al-e Ahmad. These stories are representative of how Iranians imagined themselves as a community and how the depiction of the Western Other, particularly the American, was instrumental in forming Iranians' perceptions of Self. Each story encapsulates the sociopolitical milieu of the time as well as the responses of dissident Iranian intellectuals to the same. The first three stories were written in the decades that began with the Constitutional Revolution of 1906-1911 and coincided with the reign of Reza Shah Pahlavi (1922-1944). Three phases distinguish this period: one, Iranian nationalism replaces Islamic concept ions of Self; two, Iranian nationalism embraces Bolshevik internationalism; three, institutionalized nationalism assisted by Americans is rejected. Written after the emergence of the USA as the main Western power in Iran in August 1953, the next three stories demonstrate three new phases: one, a fear of religious and cultural conversion by the USA and succumbing to national chauvinism as a defense mechanism; two, the lack of national pride and independence; three, a return to conservative Islamic convictions, at the apex of which was the fall of Mohammad Reza Shah in February 1979 and the establishment of the Islamic Republic of Iran.
Localization of ligand-induced phosphorylation sites to serine clusters in the C-terminal domain of the Dictyostelium cAMP receptor, cAR1.

Abstract When Dictyostelium cells are stimulated with cyclic adenosine 3',5'-monophosphate (cAMP), the major surface cAMP receptor expressed in early development, cAR1, undergoes a rapid phosphorylation and parallel decrease in electrophoretic mobility which may serve to regulate the activity of this G protein-coupled receptor. Biochemical analyses indicate the electrophoretic mobility shift is caused by phosphorylation of serine residues within the C-terminal cytoplasmic domain. The 18 serines of this domain are grouped in four clusters, designated 1 to 4 (in N- to C-terminal order). Two approaches were taken to determine the distribution of phosphorylation sites among the serine clusters. First, a proteolytic analysis of the C-terminal domain was performed. Second, mutants lacking various combinations of the serine clusters were created by site-directed mutagenesis and their abilities to undergo ligand-induced modification were determined. Both approaches yielded corroborative results consistent with the following model: the stimulus induces the addition of approximately two phosphates to cluster 1 and one to cluster 2; basal phosphorylation occurs predominantly in cluster 3 and to a lesser extent in cluster 2; and cluster 4 is not phosphorylated. The phosphorylation-deficient receptor mutants should be useful for establishing the role of ligand-induced phosphorylation of cAR1 in chemotaxis, cell-cell signaling, and gene expression.
Chromogranin A in patients with acid hypersecretion and/or hypergastrinaemia.

Summary Background Chromogranin has been proposed as a marker for gastrin-dependent enterochromaffin-like cell proliferation. Aim To examine this question in three populations: acid hypersecretors with gastrinoma (Zollinger–Ellison), or without gastrinoma (non-Zollinger–Ellison), and also in pernicious anaemia with achlorhydria-caused hypergastrinaemia. Methods We measured serum chromogranin, gastrin, gastric secretion and counted and quantified hyperplasia of enterochromaffin-like cells in gastric biopsies from 38 Zollinger–Ellison and 13 non-Zollinger–Ellison patients being treated with lansoprazole, for 5 years (median) and again 2.5 years later. We also studied 12 patients with pernicious anaemia, half with gastric enterochromaffin-like cell carcinoids. Results Serum chromogranin was elevated in patients with gastrinoma, even without any enterochromaffin-like cell proliferation, but not in non-Zollinger–Ellison acid hypersecretors with normal gastrin (P < 0.001). In the hypersecretors chromogranin correlated well with serum gastrin (r = 0.82), but not with enterochromaffin-like cell proliferation. Moreover, chromogranin was normal or near normal (<75 ng/mL) despite very high serum gastrin in five of six patients with pernicious anaemia and enterochromaffin-like cell carcinoids. Conclusions Chromogranin is not a reliable marker for enterochromaffin-like cell activity or proliferation up to and including carcinoid; chromogranin originates in the gastrinoma and, like gastrin, is a marker for gastrinoma in acid hypersecretors.
Book’s Impact on the Theory of Thue Systems — Abstract

During the 1980’s, Ronald V. Book was absorbed in the study of Thue systems, with applications to string-rewriting systems in mind. Influenced by the work of Nivat and his collaborators in the 1970’s ([3]; see also [1]), he focused on classes of Thue systems that operated efficiently but without full computational generality. He had many collaborators in this study, including doctoral students and post-doctoral fellows. His work was influential both directly and indirectly, as many of those who had worked with him continued their research, sometimes with still new collaborators.
Mechanisms of cation permeation across apical cell membrane of Necturus gallbladder: effects of luminal pH and divalent cations on K+ and Na+ permeability.

Conventional microelectrode techniques were combined with unilateral mucosal ionic substitutions to determine the effects of luminal pH and luminal alkali-earth cation concentrations on apical membrane cation permeability inNecturus gallbladder epithelium. Acidification of the mucosal solution caused reversible depolarization of both cell membranes and increase of transepithelial resistance. Low pH media also caused: (a) reduction of the apical membrane depolarization induced by high K, and (b) increase of the apical membrane hyperpolarization produced by Na replacement with Li or N-Methyl-d-glucamine. These results, in conjunction with estimates of cell membrane conductances, indicate that acidification of the luminal solution produces a reduction of apical membrane K permeability (PK). Addition of alkali earth cations (Mg2+, Ca2+, Sr2+, or Ba2+) produced cell membrane depolarization, increase of relative resistance of the luminal membrane and reduction of the apical membrane potential change produced by a high-K mucosal medium. These results, as those produced by low pH, can be explained by a reduction of apical membranePK. The effects of Ba2+ on membrane potential and relative apical membranePK were larger than those of all other four cations at all concentrations tested (1–10mm). The effect of Sr2+ was significantly larger than those of Mg2+ and Ca2+ at 10mm, but not different at 5mm. The reduction ofPK produced by mucosal acidification appears to be mediated by: (a) nonspecific titration of membrane fixed negative charges, and (b) an effect of luminal proton activity on the apical K channel. Divalent cations reduce apical membranePK probably by screening negative surface charges. The larger magnitude of the effects of Ba2+ and Sr2+ can be explained by binding to membrane sites, in the surface or in the K channel, in addition to their screening effect. We suggest that the action of luminal pH on K secretion in some segments of the renal tubule could be mediated in part by this pH-dependent K permeability of the luminal membrane.
Copolymers of trioxane with 2,3‐epoxypropyl acrylate: Thermally stable polyacetal copolymer networks

Cationic copolymerization of trioxane with 2,3-epoxypropyl acrylate gives thermally stable crosslinked copolymer in high yield. The structure of the crosslinked copolymer has been characterized by solid state 13C NMR spectroscopy. The comonomer acrylate group functions as a crosslinking agent in the polymerization process as well as a bound stabilizer in the resulting network. The crystallinity of the copolymer is unusually low compared to copolymers with comparable incorporation levels of the comonomers. The crosslinked acetal copolymer has the potential for further modification through its pendant acrylate group.
Characterization of immunoreactive thyrotropin releasing hormone in human fetal cerebellum.

High concentrations (411 +/- 30 pg/mg protein; mean +/- S.E., n = 12) of immunoreactive TRH (TRHi) were detected in extracts of human fetal cerebellum (13-26 weeks gestation). The TRHi in the cerebellar extracts, when subjected to gel filtration and high performance liquid chromatography (HPLC), co-migrated with synthetic TRH. In each instance, no TRHi was detected which did not share identical chromatographic mobilities with synthetic TRH. Like synthetic TRH, the TRHi in extracts of fetal cerebellum and hypothalamus was insoluble in diethyl ether and was efficiently degraded when incubated at 37 degrees C with adult rat serum. No significant degradation of TRHi occurred when the incubation was conducted at 0 degrees C or when the extracts were incubated with rat serum that had been preheated at 60 degrees C for 20 min. Neither synthetic TRH nor TRHi in extracts of fetal cerebellum of hypothalamus was degraded when incubated with human umbilical cord serum at 37 degrees C or 0 degrees C. The results of this study are supportive of the view that the TRHi in extracts of human fetal cerebellum is identical to TRH.
Assessing snowmelt dynamics with NASA scatterometer (NSCAT) data and a hydrologic process model

Abstract The presence of snow strongly impacts the exchange of moisture and energy between the land surface and atmosphere. In the interior of the northern hemisphere continents, snowmelt on frozen soils can cause or exacerbate major floods. Microwave remote sensing from satellite platforms has the potential to monitor the freeze–thaw status of soil and overlying snow packs over large areas. We evaluate the backscatter response of the NSCAT scatterometer to changing snow surface conditions, especially freeze and thaw status, using a macroscale hydrology model and the NSCAT backscatter data for the upper Mississippi River basin of the north central U.S. and the Boreal Ecosystem Atmosphere Study (BOREAS) region in central Canada. We compared the snowmelt conditions simulated by the Variable Infiltration Capacity (VIC) macroscale hydrology model driven with surface meteorological observations with NSCAT measurements for 1996–1997 snow season. A mid-winter thaw event (in February) and late season melt (April–May) are evaluated for both regions. Comparison of backscatter images with daily and hourly-modeled snow surface wetness and temperature showed that the model agreed with the backscatter for snow surface wetness on some days but not on others. Factors such as NSCAT overpass times, vegetation on the ground and their freeze–thaw state, and liquid moisture content appear to contribute to these discrepancies.
Information and Knowledge Management in Public Sector Networks: The Case of the US Intelligence Community

Abstract This article contributes to the public management literature by exploring the critical challenges that underpin the construction of robust information and knowledge management strategies in networked settings. The ability of the network to sustain itself, thrive, and achieve its objectives depends on the success that the network has in organizing and coordinating its constituent organizations. The network's collaborative information and knowledge management strategy is critical to the functioning of the network and the achievement of objectives. A robust information and knowledge management strategy will bring organizations in the network together, help them share resources, collaborate on efforts, and further their objectives in a holistic manner. An inadequate information and knowledge management strategy might lead to disconnects in organizations due to lack of information sharing, poor collaborative knowledge generation, lack of coordination, leading to a fragmented network. Drawing on a mult...
Density functional theory model of adsorption on amorphous and microporous silica materials.

We present a novel quenched solid density functional theory (QSDFT) model of adsorption on heterogeneous surfaces and porous solids, which accounts for the effects of surface roughness and microporosity. Within QSDFT, solid atoms are considered as quenched component(s) of the solid−fluid system with given density distribution(s). Solid−fluid intermolecular interactions are split into hard-sphere repulsive and mean-field attractive parts. The former are treated with the multicomponent fundamental measure density functional. Capabilities of QSDFT are demonstrated by drawing on the example of adsorption on amorphous silica materials. We show that, using established intermolecular potentials and a realistic model for silica surfaces, QSDFT quantitatively describes adsorption/desorption isotherms of Ar and Kr on reference MCM-41, SBA-15, and LiChrosphere materials in a wide range of relative pressures. QSDFT offers a systematic approach to the practical problems of characterization of microporous, mesoporous, ...
Monte Carlo analysis of experiments on individual adatoms

Abstract Quantitative studies of individual adatom motion using the field ion microscope are difficult in as much as the number of observations is limited. However, simulations by Monte Carlo techniques make it possible to maximize the information obtained from small statistical samples. Questions encountered in studying the diffusion and interaction of adatoms have therefore been examined by simulation, and results are presented for the following topics: (1) Corrections for the finite size of planes on which atomic diffusion is observed. (2) Statistical scatter in the estimation of diffusion parameters from the temperature dependence of the mean-square displacement. (3) Conditions for measuring rates of single- and double-length jumps in atomic diffusion. (4) Uncertainties in the estimation of interaction energies from pair distribution measurements.
The effect of phenylethynyl terminated imide oligomer molecular weight on the properties of composites

As part of a program to develop high temperature/high performance structural resins for applications on a Mach 2.4 high speed civil transport, a phenylethynyl terminated imide oligomer designated P...
Bound Cations in Cucumber Pickle Mesocarp Tissue as Affected by Brining and CaCl2

The effects of brining, fermentation, storage, time of CaCl2 addition and concentration of NaCl and CaCl2 on Ca++, Mg++, Na+, and K+ bound to middle lamella-cell wall material of cucumber pickle mesocarp tissue were examined. Changes in the amount of each bound cation occurred rapidly during the first 2 days of brining; levels then remained relatively stable during fermentation and storage if concentrations of NaCl or CaCl2 in brines were not altered. NaCl reduced levels of bound Ca++, Mg++, and K+, and the presence of CaCl2 increased the amount of bound Ca++ by displacing the other cations. Delayed addition of CaCl2 to brines enhanced the content of bound Ca++, indicating that levels of bound Ca++ may not be related to maintenance of firmness.
Gauge-invariant calculation of the magnetic susceptibility of the hydrogen molecule

The perpendicular component of the magnetic susceptibility of the hydrogen molecule is calculated in a gauge-invariant manner. This is accomplished by implementing the approximation in which the induced current density is taken perpendicular to the uniform magnetic field when this field is along a principal axis of ${\ensuremath{\chi}}_{\ensuremath{\alpha}\ensuremath{\beta}}$. A variational calculation using a zero-field orbital of Coulson then yields ${\ensuremath{\chi}}_{\ensuremath{\perp}}=\ensuremath{-}4.107\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ ${\mathrm{cm}}^{3}$/mole. This value falls within the theoretical bounds determined by Rebane with a maximum error of less than one percent. The Coulson orbital gives results for ${\ensuremath{\chi}}_{\mathrm{av}}$ and ${\ensuremath{\chi}}_{\ensuremath{\perp}}\ensuremath{-}{\ensuremath{\chi}}_{\ensuremath{\parallel}}$ that compare well with experiment.
Passing Our Lives through the Fire of Thought: The Personal Essay in the Political Theory Classroom

Why are teachers afraid of sentences that begin with “I feel …” or that draw on personal experience? When Enid Bloch, a former practitioner of political science, asked her colleagues these questions, she was given the standard answer of “subjectivity” or “when someone brings up personal feelings there is nothing to discuss” ( 1999 , 69–73). That may be true for other subfields of political science but surely the books we teach in political theory are brimming with subjectivity. Aren't they? And surely the essays we assign call for injecting the writing self into the broader political discussion. Don't they? So what gets in the way?
Collector signal delay time and collector transit time of HBTs including velocity overshoot

Abstract The collector signal delay time τ CT and collector transit time τ ′ CT in the heterojunction bipolar transistor (HBT) are studied and discussed using the delay time concept. Based on the assumption that the free carrier travels with the saturation velocity ν s in the base-collector space-charge region, τ ′ CT is conventionally modeled as 0.5 τ CT , which equals W C /2 ν s , where W C is the thickness of the collector depletion region. For an HBT in which velocity overshoot can occur in the collector layer, the constant velocity profile used conventionally is questionable. In addition to the constant velocity profile and the step-like velocity profile proposed more recently, the present study considers also a more realistic velocity profile consisting of a linear-dependent velocity in the velocity overshoot region and an average velocity in the rest of the collector space-charge region. This piecewise-linear velocity profile resembles closely that predicted by Monte-Carlo simulations reported in the literature. It is shown that τ ′ CT can be notably smaller than 0.5 τ CT , particularly when velocity overshoot is significant. Cutoff frequencies calculated from the present approach using the piecewise-linear velocity profile are in better agreement with Monte-Carlo simulation than that calculated from the constant and step-like velocity profiles.
Patterns of ST-segment change during acute no-flow myocardial ischemia produced by balloon occlusion during angioplasty of the left anterior descending coronary artery

Abstract An early manifestation of acute myocardial ischemia is the development of ST-segment and T-wave changes. Clinical decisions for treatment are based on ST-segment shifts on the surface electrocardiogram (ECG). ST-segment depression is believed to represent subendocardial involvement, with less extensive myocardial injury. ST-segment elevation reflects transmural involvement, with greater extent of myocardial injury. 1−3 ST-segment depression is generally induced by factors that increase myocardial demand, such as atrial pacing or exercise stress, whereas ST-segment elevation is induced by near total cessation of coronary blood flow. After acute total occlusion of the vessel, myocardial injury is believed to progress from the endocardium to the epicardial layers. Thus, we would expect to observe ST-segment depression progressing through an isoelectric point to ST-segment elevation. This may explain why some patients have no significant changes on the ECG when presenting with an acute myocardial infarction. To test this hypothesis in humans, we used balloon angioplasty of the coronary arteries as the model for acute noflow ischemia. Intracoronary electrograms were obtained from the center of the ischemic zone by attaching the proximal end of the balloon angioplasty guidewire to the V 1 lead on the surface ECG. Patterns of ST-segment responses on the intracoronary electrogram and surface leads II and V 5 were continuously recorded.
Nucleation in surface catalyzed chemical vapor deposition (CVD)

Abstract The theory of heterogeneous nucleation for a one-component system (physical vapor deposition, PVD) is outlined, and possible theoretical modifications required when dealing with multicomponent systems (chemical vapor deposition, CVD) are enumerated. The pertinent steps in nucleation in a dissociation-type reaction are adsorption, decomposition, on the substrate, and formation of nuclei by surface diffusion processes. In the present study, nucleation of chromium from chromous iodide on fused-quartz substrates was studied as an example of a dissociation type CVD process. Depending on the substrate temperature, the molecules either thermally decomposed on the substrate yielding free chromium and evolving iodine, or, at low substrate temperatures, formed chromous iodide deposits directly. The concentration developed on the substrate surface for any species is given by a balance between the rate of supply and the rate of desorption. These characteristics, along with the decomposition kinetics of the reaction, provide a means for definition of possible temperature intervals for PVD and CVD. In the chromous iodide system, PVD and CVD obtain in well-defined and separated temperature intervals. However, it is shown that the greatest degree of control over this interval is afforded by the adsorption characteristics of the species on the substrate. Therefore, the choice of substrate material is an important factor influencing the conditions under which vapor deposition occurs. For the PVD case, tentative agreement was found however for two mechanisms: (1) direct addition of chromous iodide molecules to a capshaped nucleus and (2) surface diffusion to a disc-shaped nucleus. In CVD it was found that extensive reaction with the substrate, forming Cr 2 O 3 and Cr 3 Si, preceded nucleation of chromium films, these complex reactions occurring at temperatures as low as 527°C.
Characterization and comparison of two penicillinase-producing strains of Streptococcus (Enterococcus) faecalis.

Abstract We identified two beta-lactamase-positive enterococci. One strain was high-level (MIC, greater than 2,000 microgram/ml) gentamicin resistant; the other was not (MIC, 12.5 microgram/ml). beta-Lactamase production was extrachromosomally mediated in both strains, and both strains showed an inoculum effect reversed by beta-lactamase inhibitors. The strain lacking high-level gentamicin resistance showed synergistic killing with a combination of penicillin, clavulanic acid, and gentamicin.
Swedish Vietnam criticism reconsidered: Social Democratic Vietnam policy a manifestation of Swedish Ostpolitik?

Between 1965 and 1973, Sweden's Social Democratic government emerged as the most strident West European critic of the American war effort in Indochina. Although the latter's unmatched militancy on the Vietnam question had its origins in Swedish domestic politics, this policy likewise had implications for the country's relations to both superpowers. Given that Swedish Vietnam criticism coincided with the relative decline of American economic and military strength as well as with the Soviets' attainment of nuclear parity, this article asks whether this policy might be interpreted as one component in a broader strategy to secure the Kremlin's good graces at a time when the strategic balance in Europe appeared to be on the verge of shifting in the USSR's favour? It concludes that – regardless of whether or not this policy was, at first, intentionally designed to have this effect – it ultimately served to put Swedish–Soviet relations on a better footing.
Explanation for the Inversion of an UCST Phase Diagram to a LCST Diagram in Binary Polybutadiene Blends

A simplified version of the random copolymer lattice cluster theory has been applied to explain the variation in the nature of the phase transition (upper vs lower critical solution temperature pha...
CONSERVED MOMENTS IN NONEQUILIBRIUM FIELD DYNAMICS

We demonstrate with the example of Cahn-Hilliard dynamics that the macroscopic kinetics of first-order phase transitions exhibits an infinite number of constants of motion. Moreover, this result holds in any space dimension for a broad class of nonequilibrium processes whose macroscopic behavior is governed by equations of the form ∂φ/∂t = ℒW(φ), where Φ is an “order parameter,”W is an arbitrary function of Φ, and ℒ is a linear Hermitian operator. We speculate on the implications of this result.
Functionalized polymeric liposomes. Efficient immobilization of alpha chymotrypsin

A polymerizable phospholipid has been synthesized having a latent aldehyde moiety in the head group (1). Photopolymerized vesicles which have been prepared from this phosphatidylcholine have been successfully conjugated to alpha chymotrypsin. A high degree of loading was achieved with significant retention of enzymatic function.