cssi/SciSciGPT-SciSciNet huggingface dataset:
How do banking crises affect bilateral exports

This paper investigates whether banking crises are associated with declines in bilateral exports. We first develop a simple open economy model in which banking crises translate into negative liquidity shocks, leading to collapses in exports through supply-side and demand-side shocks. We then estimate a gravity model using a sample of 75 countries over the 1988–2010 period. The results suggest that crisis-hit countries experience lower levels of bilateral exports. Exports of manufactured goods are disproportionately hurt by crises, and this negative effect is stronger in industries relying more on external finance. These findings are robust to correcting for potential endogeneity, to controlling for outliers, and to using alternative estimation methods.
Optimizing Throughput in a MIMO System With a Self-Sustained Relay and Non-Uniform Power Splitting

We present a novel approach to maximize the transmission rate in a MIMO relay system, where all nodes are equipped with multiple antennas and the relay is self-sustained by harvesting energy using a non-uniform power splitting method. By deriving a closed-form solution for the optimal power splitting ratios for harvesting at the relay and the optimal power allocation for precoding at both source and relay, we are able to design an efficient primal-dual algorithm to jointly optimize for these variables, instead of solving for them sequentially as traditionally done. We demonstrate the algorithm efficiency at reducing the run-time by several orders of magnitude compared to standard solvers and existing sequential algorithms, making our algorithm highly amenable to massive MIMO settings. Numerical results further reveal the significant rate gain of non-uniform power splitting over traditional uniform splitting.
Minimization of Drug Shortages in Pharmaceutical Supply Chains: A Simulation-Based Analysis of Drug Recall Patterns and Inventory Policies

The drug shortage crisis in the last decade not only increased health care costs but also jeopardized patients’ health across the United States. Ensuring that any drug is available to patients at health care centers is a problem that official health care administrators and other stakeholders of supply chains continue to face. Furthermore, managing pharmaceutical supply chains is very complex, as inevitable disruptions occur in these supply chains (exogenous factors), which are then followed by decisions members make after such disruptions (internal factors). Disruptions may occur due to increased demand, a product recall, or a manufacturer disruption, among which product recalls—which happens frequently in pharmaceutical supply chains—are least studied. We employ a mathematical simulation model to examine the effects of product recalls considering different disruption profiles, e.g., the propagation in time and space, and the interactions of decision makers on drug shortages to ascertain how these shortages can be mitigated by changing inventory policy decisions. We also measure the effects of different policy approaches on supply chain disruptions, using two performance measures: inventory levels and shortages of products at health care centers. We then analyze the results using an approach similar to data envelopment analysis to characterize the efficient frontier (best inventory policies) for varying cost ratios of the two performance measures as they correspond to the different disruption patterns. This analysis provides insights into the consequences of choosing an inappropriate inventory policy when disruptions take place.
The Effect of Economic Conditions on the Disability Insurance Program: Evidence from the Great Recession

Abstract We examine the effect of job displacement during the Great Recession on the Social Security Disability Insurance (SSDI) program. Exploiting variation in the severity and timing of the recession across states, we estimate the effect of unemployment on SSDI applications and awards. We find the Great Recession induced nearly one million SSDI applications that otherwise would not have been filed, of which 41.8% were awarded benefits, resulting in over 400,000 new beneficiaries who made up 8.9% of all SSDI entrants between 2008 and 2012. More than one-half of the recession-induced awards were made on appeal. The induced applicants had less severe impairments than the average applicant. Only 9% had the most severe, automatically-qualifying impairments, 33% had functional impairments and no transferable skills, and the rest were denied for having insufficiently severe impairments and/or transferable skills. Our estimates imply the Great Recession increased claims processing costs by $2.960 billion during 2008–2012, and SSDI benefit obligations by $55.730 billion in present value, or $97.365 billion including both SSDI and Medicare benefits.
Validity of Field and Laboratory Three-Compartment Models in Healthy Adults.

ABSTRACTModified laboratory- and field-based multicompartment models have been found valid for estimating body composition. However, the comparability between these models is unknown.PurposeThis study determined the validity of field and laboratory three-compartment (3C) models in healthy adults.Met
Pharmacogenomics of Novel Direct Oral Anticoagulants: Newly Identified Genes and Genetic Variants

Direct oral anticoagulants (DOAC) have shown an upward prescribing trend in recent years due to favorable pharmacokinetics and pharmacodynamics without requirement for routine coagulation monitoring. However, recent studies have documented inter-individual variability in plasma drug levels of DOACs. Pharmacogenomics of DOACs is a relatively new area of research. There is a need to understand the role of pharmacogenomics in the interpatient variability of the four most commonly prescribed DOACs, namely dabigatran, rivaroxaban, apixaban, and edoxaban. We performed an extensive search of recently published research articles including clinical trials and in-vitro studies in PubMed, particularly those focusing on genetic loci, single nucleotide polymorphisms (SNPs), and DNA polymorphisms, and their effect on inter-individual variation of DOACs. Additionally, we also focused on commonly associated drug-drug interactions of DOACs. CES1 and ABCB1 SNPs are the most common documented genetic variants that contribute to alteration in peak and trough levels of dabigatran with demonstrated clinical impact. ABCB1 SNPs are implicated in alteration of plasma drug levels of rivaroxaban and apixaban. Studies conducted with factor Xa, ABCB1, SLCOB1, CYP2C9, and VKORC1 genetic variants did not reveal any significant association with plasma drug levels of edoxaban. Pharmacokinetic drug-drug interactions of dabigatran are mainly mediated by p-glycoprotein. Strong inhibitors and inducers of CYP3A4 and p-glycoprotein should be avoided in patients treated with rivaroxaban, apixaban, and edoxaban. We conclude that some of the inter-individual variability of DOACs can be attributed to alteration of genetic variants of gene loci and drug-drug interactions. Future research should be focused on exploring new genetic variants, their effect, and molecular mechanisms that contribute to alteration of plasma levels of DOACs.
Training Graduate Teaching Assistants in the Geosciences: Our Practices vs. Perceived Needs

In response to calls for reformed teaching practices in college STEM labs and courses, and to support graduate teaching assistants (GTAs) in their general teaching responsibilities, other STEM disc...
Conditional Standard Errors of Measurement

Errors of measurement for test scores generally are viewed as random and unpredictable. Conditional standard errors of measurement (SEMs) index the amount of error in the measurement process and are required to be reported for tests. Methods of estimating conditional SEMs, based on both classical test theory and generalizability theory, are described in this entry. These methods are based on differing assumptions, but the conditional SEMs estimates obtained from these methods are commonly highly related for educational achievement tests. Conditional SEMs vary by score level. Conditional SEMs typically have high values for extreme scores and have low values for middle scores on the raw score scale. However, a nonlinear transformation of the raw scores to scale scores can lead to conditional SEMs that have other patterns across score levels. Keywords: conditional standard errors of measurement; classical test theory; generalizability theory; scale score
High Rates of Readmission in Necrotizing Pancreatitis: Natural History or Opportunity for Improvement?

Necrotizing pancreatitis (NP) is a complex and heterogeneous disease with a protracted disease course. Hospital readmission is extremely common; however, few data exist regarding the cause of readmission in NP. A retrospective review of NP patients treated between 2005 and 2017 identified patients readmitted both locally and to our hospital. All patients with unplanned hospital readmissions were evaluated to determine the cause for readmission. Clinical and demographic factors of all patients were recorded. As appropriate, two independent group t tests and Pearson’s correlation or Fisher’s exact tests were performed to analyze the relationship between index admission clinical factors and readmission. p values of < 0.05 were accepted as statistically significant. Six hundred one NP patients were reviewed. Median age was 52 years (13–96). Median index admission length of stay was 19 days (2–176). The most common etiology was biliary (49.9%) followed by alcohol (20.0%). Unplanned readmission occurred in 432 patients (72%) accounting for a total of 971 unique readmissions (mean readmissions/patient, 2.3). The most common readmission indications were symptomatic necrosis requiring supportive care and/or intervention (31.2%), infected necrosis requiring antibiotics and/or intervention (26.6%), failure to thrive (9.7%), and non-necrosis infection (6.6%). Patients requiring readmission had increased incidence of index admission renal failure (21.3% vs. 14.2%, p = 0.05) and cardiovascular failure (12.5% vs. 4.7%, p = 0.01). Readmission in NP is extremely common. Significant portions of readmissions are a result of the disease natural history; however, a percentage of readmissions appear to be preventable. Patients with organ failure are at increased risk for unplanned readmission and will benefit from close follow-up.
Proceedings of the 1st ACM workshop on Research on enterprise networking

Welcome to the first Workshop: Research on Enterprise Networking -- WREN 2009. We established this workshop to generate papers and discussion on research challenges and results specific to enterprise and data-center networks. Enterprise networks (in large corporations, universities, government entities, etc.) use much of the same technology as the Internet, but otherwise differ in important and interesting ways. Also, net spending on enterprise network equipment is much larger than analogous spending by ISPs. However, most academic researchers have focussed on public networks such as the Internet. WREN, we hope, will help to broaden that focus. We knew we were taking a risk in starting a new workshop, to be held outside the US, on a topic whose primary experts might be suffering from limited travel budgets (to put it mildly). Therefore, we did a lot of work to solicit papers (and, as program chair, I want to thank the WREN PC members for a lot of help contacting potential authors.) I am happy to report that we received more good submissions than we could accept. We received 24 submissions from at least eight countries, and accepted 13 papers, including two from industry authors outside research labs. Most papers received five reviews, and the PC was generally quite impressed with the quality of the submissions; people are doing a lot of interesting enterprise-related network research, and we expect that this topic will become more visible in the future.
Proceedings of the 2016 ACM Workshop on Moving Target Defense

It is our great pleasure to welcome you to the 2016 MTD (Moving Target Defense) Workshop. This workshop seeks to bring together researchers from academia, government, and industry to report on the latest results on moving-target defense research, and to have productive discussion and constructive debate on this topic. The workshop is a single day event co-located with the 2016 ACM Conference on Computer and Communications Security (ACM CCS). Out of a total of 26 submissions from Asia, Europe, and North America, we accepted 9 regular papers and 2 short papers. In addition, we have accepted one system demo. We also encourage attendees to attend the keynote and invited talk presentations. These valuable and insightful talks will give us a better understanding of the future: A Cyber Mutation: Metrics, Techniques and Future Directions, Ehab Al-Shaer (who is currently at UNC Charlotte) Moving Target Defense - A Journey from Idea to Product, Jason Li (who is currently at Intelligent Automation, Inc.)
Chapter 14 – Applying Financial Models: To Value, Structure, and Negotiate Stock and Asset Purchases

In this chapter, the focus is on the application of financial modeling to value and structure mergers and acquisitions (M&As). A detailed discussion of how to construct M&A financial models is beyond the scope of this chapter. Rather, the intent of this chapter is to provide the reader with an appreciation of the general characteristics of such models, their data input requirements, and how they may be used to address questions relating to valuation, deal structuring, and financing. For example, models help an acquirer determine the implications of various possible deal structures before submitting an initial offer and in assessing the implications of various financing or postclosing capital structures (i.e., the composition of financing). Both acquirers and target firms can use models to evaluate rapidly alternative proposals and counterproposals likely to arise during the negotiation process. Models also help all parties to the transaction understand the key determinants of value and the relative contribution of each party to value creation. Such information is critical to each side in the negotiating process in determining an appropriate purchase price and distribution of risk.
Dynamic Replication and Hedging: A Reinforcement Learning Approach

The authors of this article address the problem of how to optimally hedge an options book in a practical setting, where trading decisions are discrete and trading costs can be nonlinear and difficult to model. Based on reinforcement learning (RL), a well-established machine learning technique, the authors propose a model that is flexible, accurate and very promising for real-world applications. A key strength of the RL approach is that it does not make any assumptions about the form of trading cost. RL learns the minimum variance hedge subject to whatever transaction cost function one provides. All that it needs is a good simulator, in which transaction costs and options prices are simulated accurately.
Impact of Supervisory Support on Turnover Intention: The Mediating Role of Burnout and Job Satisfaction in a Longitudinal Study

High rates of provider turnover are problematic for our mental health system. Research indicates that supervisory support could alleviate some turnover intention by decreasing emotional exhaustion (a key component of burnout) as well as by increasing job satisfaction. However, the potential mediation mechanisms have not been rigorously tested. Longitudinal data collected from 195 direct clinical care providers at two community mental health centers identified positive effects of supervisory support on reduced turnover intention through reduced emotional exhaustion. Job satisfaction was not a significant mediator. Supervisory support may help mitigate turnover intention through work-related stress reduction.
Total synthesis of the L-hexoses

Abstract Enantiomerically pure polyhydroxylated natural products are synthesized by using a reiterative two-carbon extension cycle consisting of four key transformations. The generality and efficiency of this methodology are demonstrated in the total synthesis of all eight L-hexoses.
Firms' and states’ responses to laxer environmental standards

On June 1, 2017, President Trump announced the United States' withdrawal from the Paris agreement on climate change. Despite this decision, American firms continued investing in low-carbon technologies and some states committed to tougher environmental standards. To understand this apparent paradox, this paper studies how a weakening of environmental standards affects the behavior of profit-maximizing firms. It finds that a relaxation of emission standards (i) may increase firms' incentives to adopt clean technologies, but not to pollute less; (ii) may negatively affect industry profitability if it is perceived as temporary; and, when this is the case, (iii) the unilateral adoption of stricter standards by large states may increase the expected profitability of every firm.
Productive specialization, peaceful cooperation and the problem of the predatory state: lessons from comparative historical political economy

This paper reconceptualizes and unbundles the relationship between public predation, state capacity and economic development. By reframing our understanding of state capacity theory from a constitutional perspective, we argue that to the extent that a causal relationship exists between state capacity and economic development, the relationship is proximate rather than fundamental. State capacity emerges from an institutional context in which the state is constrained from preying on its citizenry in violation of predefined rules limiting its discretion. When political constraints are not established to limit political discretion, then state capacity will degenerate from a means of delivering economic development to a means of predation. In addition, we investigate two case studies of economic and political transition: the privatization of Russia following the collapse of the Soviet Union; and the political unification of Sicily with the Italian peninsula following the Napoleonic Wars. In each case, political and economic transition intended to secure well-defined and well-enforced property rights empowered the predatory capacity of the state. In each case, the attempt to redistribute property rights through political discretion only facilitated predation by the political elite.
Pediatric thymectomy: a study of national trends in demographics, short-term outcomes, and cost.

Thymectomy in pediatric patients is an effective treatment for myasthenia gravis (MG), thymic neoplasms, and other rarer pathologies. It is an uncommon procedure in children and studies have focused on small, single-institution cohorts. We sought to better characterize its use by utilizing a national database. The Kids’ Inpatient Database was used to identify hospital discharge records of patients ≤ 20 years old who underwent thymectomy. A retrospective cross-sectional analysis for 2003, 2006, 2009, and 2012 was performed. Trends in patient characteristics, diagnosis, surgical approach, and short-term outcomes were analyzed. Risk factors were identified using univariate and multivariate analyses. There were 600 thymectomies identified. MG was the most common indication. Thoracoscopy is being used increasingly for all diagnoses except malignancy. The overall morbidity rate was 14.0%, with respiratory complications representing the largest group. No in-hospital deaths were identified. Private insurance was associated with shorter hospital stays and lower costs. Hispanic race was associated with more complications, longer stays, and higher costs. Thoracoscopic thymectomies had shorter stays than open procedures. Thymectomy in the pediatric population is being performed safely, with low morbidity and no identified mortalities. Thoracoscopy results in reduced length of stay and is being used increasingly. Of note, socioeconomic and racial factors impact outcomes.
Dominant Suborbital Space Tourism Architectures

In the early stages of maturity of a system built for a specific function, it is common for the solutions to lie in a broad architectural space, in which numerous concepts are being developed, buil...
A high-throughput whole cell screen to identify inhibitors of Mycobacterium tuberculosis

Tuberculosis is a disease of global importance for which novel drugs are urgently required. We developed a whole-cell phenotypic screen which can be used to identify inhibitors of Mycobacterium tuberculosis growth. We used recombinant strains of virulent M. tuberculosis which express far-red fluorescent reporters and used fluorescence to monitor growth in vitro. We optimized our high throughput assays using both 96-well and 384-well plates; both formats gave assays which met stringent reproducibility and robustness tests. We screened a compound set of 1105 chemically diverse compounds previously shown to be active against M. tuberculosis and identified primary hits which showed ≥ 90% growth inhibition. We ranked hits and identified three chemical classes of interest-the phenoxyalkylbenzamidazoles, the benzothiophene 1-1 dioxides, and the piperidinamines. These new compound classes may serve as starting points for the development of new series of inhibitors that prevent the growth of M. tuberculosis. This assay can be used for further screening, or could easily be adapted to other strains of M. tuberculosis.
Heliphenes and Related Structures

This review discusses from a qualitative viewpoint three-dimensional structures (hydrocarbons and carbon allo- tropes) that can be obtained from the 4,6,12-archimedean tiling of the Euclidean plane (graphenylene net) or that are re- lated to subgraphs derived from the graphenylene net, insisting on helical structures called (n)heliphenes with alternating 4- and 6-membered conjugated rings. Analogies with benzenoid (n)helicenes allow proposals for non-planar heliphene- related structures that have yet to be explored.
Crop Yield Prediction Using Deep Neural Networks.

The world’s population is on the rise and in order to feed the world in 2050, food production will need to increase by 70% [1]. As a result, it is of great importance to construct powerful predictive models for phenotype prediction based on Genotype and Environment data (so-called G by E problem). The objective of the G by E analysis is to understand how genotype and the environment jointly determine the phenotype (such as crop yield and disease resistance) of plant or animal species. In this research, deep neural networks are trained and used as predictive models. Deep neural networks have become a popular tool in supervise learning due to considerable ability in training nonlinear features [5]. Recent articles have stated that the network depth is a vital factor in decreasing classification or regression error. But, deeper networks have a so-called vanishing/exploding gradients problem which makes the training and optimizing deeper networks difficult. He et al. proposed residual learning method which alleviates this problem very well and showed that deep residual networks are significantly better and more efficient than previous typical networks [5]. As a result, residual training has been used in this research to prevent gradient degradation and ease the optimization process. Finally, since it is difficult to predict the yield difference directly, two separate residual neural networks have been trained to predict yield and check yield. After training the networks, the RMSE for check yield and yield are 8.23 and 10.52, respectively, which are very good because of considerable amount of missing values, uncertainty, and complexity in the datasets.
Structural and Mechanistic Investigation of Rubidium Ion Exchange in Potassium Zirconium Trisilicate

Complete and intermediate incorporation of rubidium into the hydrothermally prepared mineral umbite has been accomplished by ion exchange. Potassium zirconium trisilicate, K2ZrSi3O9·H2O, is an open...
Approximation to the Distribution of Fitness Effects across Functional Categories in Human Segregating Polymorphisms

Quantifying the proportion of polymorphic mutations that are deleterious or neutral is of fundamental importance to our understanding of evolution, disease genetics and the maintenance of variation genome-wide. Here, we develop an approximation to the distribution of fitness effects (DFE) of segregating single-nucleotide mutations in humans. Unlike previous methods, we do not assume that synonymous mutations are neutral or not strongly selected, and we do not rely on fitting the DFE of all new nonsynonymous mutations to a single probability distribution, which is poorly motivated on a biological level. We rely on a previously developed method that utilizes a variety of published annotations (including conservation scores, protein deleteriousness estimates and regulatory data) to score all mutations in the human genome based on how likely they are to be affected by negative selection, controlling for mutation rate. We map this and other conservation scores to a scale of fitness coefficients via maximum likelihood using diffusion theory and a Poisson random field model on SNP data. Our method serves to approximate the deleterious DFE of mutations that are segregating, regardless of their genomic consequence. We can then compare the proportion of mutations that are negatively selected or neutral across various categories, including different types of regulatory sites. We observe that the distribution of intergenic polymorphisms is highly peaked at neutrality, while the distribution of nonsynonymous polymorphisms has a second peak at . Other types of polymorphisms have shapes that fall roughly in between these two. We find that transcriptional start sites, strong CTCF-enriched elements and enhancers are the regulatory categories with the largest proportion of deleterious polymorphisms.
Antiferromagnetic Spin Correlations Between Corner-Shared [FeO5]7- and [FeO6]9- Units, in the Novel Iron-Based Compound: BaYFeO4

A novel quaternary compound in the Ba–Y–Fe-O phase diagram was synthesized by solid-state reaction and its crystal structure was characterized using powder X-ray diffraction. The crystal structure of BaYFeO4 consists of a unique arrangement of Fe3+ magnetic ions, which is based on alternate corner-shared units of [FeO5]7– square pyramids and [FeO6]9– octahedra. This results in the formation of stairwise channels of FeO polyhedra along the b crystallographic axis. The structure is described in an orthorhombic crystal system in the space group Pnma with lattice parameters a = 13.14455(1) A, b = 5.694960(5) A, and c = 10.247630(9) A. The temperature-dependent magnetic susceptibility data reveal two antiferromagnetic (AFM) transitions at 33 and 48 K. An upturn in the magnetic susceptibility data above these transitions is observed, which does not reach its maximum even at 390 K. The field-dependent magnetization data at both 2 and 300 K show a nearly linear dependence and do not exhibit significant hysteresis. Heat capacity measurements between 2 and 200 K reveal only a broad anomaly without any indication of long-range ordering. The latter data set is not in good agreement with the magnetic susceptibility data, which makes it difficult to exactly determine the magnetic ground statemore » of BaYFeO4. Accordingly, a temperature-dependent neutron diffraction study is in order, which will enable resolving this issue. The theoretical study of the relative strengths of magnetic exchange interactions along various possible pathways, using extended Huckel spin dimer analysis, shows that only interactions between square pyramidal and octahedral centers are significant, and among them, the intrachannel correlations are stronger than interchannel interactions. This is the first physical property study in such a magnetic ion substructure.« less
Stereoselective Synthesis of Conformationally Constrained 2‘-Deoxy-4‘-thia β-Anomeric Spirocyclic Nucleosides Featuring Either Hydroxyl Configuration at C5‘

An enantioselective approach to 2‘-deoxy-4‘-thia spirocyclic nucleosides featuring an α- or β-hydroxyl substituent at C-5‘ of the carbocyclic ring is detailed. The starting point is the mandelate a...
Synthesis and magnetic properties of colloidal MnPt3 nanocrystals.

The colloidal synthesis and magnetic properties of MnPt3 nanocrystals are reported. The nanocrystal size depended on the Mn reactant used, but the Mn:Pt stoichiometry was always 1:3. As synthesized, the nanocrystals are compositionally disordered with the face-centered cubic (fcc) A1 phase. Annealing at 580 °C changed the MnPt3 crystal structure to the compositionally ordered L12 phase (AuCu3 structure) with higher magnetocrystalline anisotropy. Magnetization measurements showed that the A1 nanocrystals are paramagnetic and the L12 MnPt3 nanocrystals are superparamagnetic.
Contributions of Hippocampus and Striatum to Memory-Guided Behavior Depend on Past Experience.

The hippocampal and striatal memory systems are thought to operate independently and in parallel in supporting cognitive memory and habits, respectively. Much of the evidence for this principle comes from double dissociation data, in which damage to brain structure A causes deficits in Task 1 but not Task 2, whereas damage to structure B produces the reverse pattern of effects. Typically, animals are explicitly trained in one task. Here, we investigated whether this principle continues to hold when animals concurrently learn two types of tasks. Rats were trained on a plus maze in either a spatial navigation or a cue–response task (sequential training), whereas a third set of rats acquired both (concurrent training). Subsequently, the rats underwent either sham surgery or neurotoxic lesions of the hippocampus (HPC), medial dorsal striatum (DSM), or lateral dorsal striatum (DSL), followed by retention testing. Finally, rats in the sequential training condition also acquired the novel “other” task. When rats learned one task, HPC and DSL selectively supported spatial navigation and cue response, respectively. However, when rats learned both tasks, HPC and DSL additionally supported the behavior incongruent with the processing style of the corresponding memory system. Thus, in certain conditions, the hippocampal and striatal memory systems can operate cooperatively and in synergism. DSM significantly contributed to performance regardless of task or training procedure. Experience with the cue–response task facilitated subsequent spatial learning, whereas experience with spatial navigation delayed both concurrent and subsequent response learning. These findings suggest that there are multiple operational principles that govern memory networks. SIGNIFICANCE STATEMENT Currently, we distinguish among several types of memories, each supported by a distinct neural circuit. The memory systems are thought to operate independently and in parallel. Here, we demonstrate that the hippocampus and the dorsal striatum memory systems operate independently and in parallel when rats learn one type of task at a time, but interact cooperatively and in synergism when rats concurrently learn two types of tasks. Furthermore, new learning is modulated by past experiences. These results can be explained by a model in which independent and parallel information processing that occurs in the separate memory-related neural circuits is supplemented by information transfer between the memory systems at the level of the cortex.
Reactions of ring‐expanded xanthines containing the imidazo[4,5‐e][1,4]diazepine ring system

4,5,7,8-Tetrahydro-6H-imidazo[4,5-e][1,4]diazepine-5,8-dione underwent bromination at the 2-position with or without substituents at the 3-, 4- or 7-position, using bromine, N-bromosuccinimide, or acetyl hypobro-mite. The activation of position 6 with an ester functionality, as in 7, did not alter the site of bromination. The base-catalyzed bromination of the ring-open precursor, diethyl 2-[N-(1-benzyl-5-nitroimidazolyl-4-carbon-yl)amino]malonate (5), resulted either in introduction of an alkoxy functionality in the above aminomalonate side-chain, yielding 17 when the reaction was quenched with an alcohol, or in degradation of the side-chain, yielding 1-benzyl-5-nitroimidazole-4-carboxamide (19) when the reaction was quenched with water. Both 17 and 19 are formed by oxidative bromination of 5 via the bromo intermediate 15. An indirect evidence for the latter was obtained by base-catalyzed methylation of 5 which gave diethyl 2-methyl-2-[N-(1-benzyl-5-nitroimid-azolyl-4-carbonyl)amino]malonate (21). The base-catalyzed bromination of 5 with N-bromosuccinimide gave rise to two products, the dimer 24a and the monomer 24b that contained the substituted 2,2-diaminomalon-ate side-chain. The structure of 24b was confirmed by single-crystal X-ray diffraction analyses. Reduction of the 5-nitro group of 17 to the corresponding amino derivative 25, followed by ring-closure with sodium meth-oxide/methanol, yielded three products, a 5:6-fused system 26 and two 5:7 fused systems 27 and 28. The structures of 26 and 27 were confirmed by single-crystal X-ray diffraction analyses. A tentative reaction pathway for the formation of all three products has been proposed. Hydrolysis of 27 with aqueous hydrochloric acid resulted in ring-opening to form 5-amino-1-benzylimidazole-4-carboxamide (40). A mechanism for the hydrolysis reaction has been proposed. Catalytic hydrogenation of 5 in acetic acid yielded the aminoimidazo-lone derivative 11 which upon ring-closure with sodium methoxide in methanol produced imidazo[4,5-e][1,4]-diazepine-2,5,8-trione (12).
Model-based spike sorting with a mixture of drifting t-distributions

Background:Chronic extracellular recordings are a powerful tool for systems neuroscience, but spike sorting remains a challenge. A common approach is to fit a generative model, such as a mixture of Gaussians, to the observed spike data. Even if non-parametric methods are used for spike sorting, such generative models provide a quantitative measure of unit isolation quality, which is crucial for subsequent interpretation of the sorted spike trains. New method: We present a spike sorting strategy that models the data as a mixture of drifting t-distributions. This model captures two important features of chronic extracellular recordings—cluster drift over time and heavy tails in the distribution of spikes—and offers improved robustness to outliers. Results: We evaluate this model on several thousand hours of chronic tetrode recordings and show that it fits the empirical data substantially better than a mixture of Gaussians. We also provide a software implementation that can re-fit long datasets in a few seconds, enabling interactive clustering of chronic recordings. Comparison with existing methods: We identify three common failure modes of spike sorting methods that assume stationarity and evaluate their impact given the empirically-observed cluster drift in chronic recordings. Using hybrid ground truth datasets, we also demonstrate that our model-based estimate of misclassification error is more accurate than previous unit isolation metrics. Conclusions: The mixture of drifting t-distributions model enables efficient spike sorting of long datasets and provides an accurate measure of unit isolation quality over a wide range of conditions.
Allylation of acetals and ketals with allyltrimethylsilane catalyzed by the mixed Lewis acid system AlBr3/CuBr

The synthesis of homoallyl ethers from various acetals and a cyclic ketal with allyltrimethylsilane catalyzed by aluminum bromide in the presence of trimethylaluminum as a desiccant is described. We found that the addition of a catalytic amount of copper(I) bromide accelerates the allylation reactions to afford the homoallyl ether derivatives in good to excellent yield.
Tandem Regio- and Stereoselective Organocuprate-Mediated Bis-Allylic Substitutions

anti-5-Acetoxy-4-halo-α,β-enoates undergo sequential or tandem reactions with two different magnesium cuprate reagents to afford anti-2,3-dialkyl-4,5-enoates in high chemical yield and with excelle...
TraceSpecks: A Software for Automated Idealization of Noisy Patch-Clamp and Imaging Data

Experimental records of single molecules or ion channels from fluorescence microscopy and patch-clamp electrophysiology often include high-frequency noise and baseline fluctuations that are not generated by the system under investigation and have to be removed. Moreover, multiple channels or conductance levels can be present at a time in the data that need to be quantified to accurately understand the behavior of the system. Manual procedures for removing these fluctuations and extracting conducting states or multiple channels are laborious, prone to subjective bias, and likely to hinder the processing of often very large data sets. We introduce a maximal likelihood formalism for separating signal from a noisy and drifting background such as fluorescence traces from imaging of elementary Ca2+ release events called puffs arising from clusters of channels, and patch-clamp recordings of ion channels. Parameters such as the number of open channels or conducting states, noise level, and background signal can all be optimized using the expectation-maximization algorithm. We implement our algorithm following the Baum-Welch approach to expectation-maximization in the portable Java language with a user-friendly graphical interface and test the algorithm on both synthetic and experimental data from the patch-clamp electrophysiology of Ca2+ channels and fluorescence microscopy of a cluster of Ca2+ channels and Ca2+ channels with multiple conductance levels. The resulting software is accurate, fast, and provides detailed information usually not available through manual analysis. Options for visual inspection of the raw and processed data with key parameters are provided, in addition to a range of statistics such as the mean open probabilities, mean open times, mean close times, dwell-time distributions for different number of channels open or conductance levels, amplitude distribution of all opening events, and number of transitions between different number of open channels or conducting levels in asci format with a single click.
Fungal community assembly in soils and roots under plant invasion and nitrogen deposition

Abstract Fungal community composition in the Anthropocene is driven by rapid changes in environmental conditions caused by human activities. This study examines the relative importance of two global change drivers – atmospheric nitrogen (N) deposition and annual grass invasion – on structuring fungal communities in a California chaparral ecosystem, with emphasis on arbuscular mycorrhizal fungi. We used molecular markers, functional groupings, generalized linear statistics and joint distribution modeling, to examine how environmental variables structure taxonomic and functional composition of fungal communities. Invasive grasses had a lower richness and relative abundance of symbiotic fungi (both AMF and other fungi) compared to native shrubs. We found a higher richness and abundance of rhizophilic (e.g. Glomeraceae) and edaphophilic (e.g. Gigasporaceae) AMF with increasing soil NO3. Our findings suggest that invasive persistence may decrease the presence of multiple soil symbionts that native species depend on for pathogen protection and increased access to soil resources.
The nucleation, growth, and stability of oxide-supported metal clusters

The optimization of oxide-supported metal clusters as heterogeneous catalysts requires a detailed understanding of the metal cluster–oxide interface. Model catalysts, prepared by deposition of a catalytically active metal onto a thin film oxide support, closely mimic real-world catalysts, yet are amenable to study using surface sensitive techniques. Surface science methods applied to model catalysts, combined with the use of in situ high-pressure reaction studies, have provided a wealth of information about cluster structure and reactivity. STM capabilities for imaging individual particles under reaction temperatures and pressures offer a new approach for studying supported cluster catalysts on a particle-by-particle basis. This article describes recent work in our laboratories using variable temperature STM to investigate the role of the support and its defects in the nucleation and stabilization of metal clusters.
General Synthesis of meso-Amidoporphyrins via Palladium-Catalyzed Amidation

A series of meso-amidoporphyrins were facilely synthesized by direct reactions of meso-brominated porphyrins with amides via palladium-catalyzed amidation reaction. Using a combination of palladium precursor Pd(OAc)2 or Pd2(dba)3 and phosphine ligand Xantphos, both 5-bromo-10,20-diphenylporphyrin and 5,15-dibromo-10,20-diphenylporphyrin, as well as their zinc complexes, can be effectively coupled with a wide variety of amides to give the corresponding mono- and bis-substituted meso-amidoporphyrins in high yields under mild conditions.
Microbial dormancy improves predictability of soil respiration at the seasonal time scale

Global warming, in combination with altered precipitation patterns, is accelerating global soil respiration, which could in turn accelerate climate change. The biological mechanisms through which soil carbon (C) responds to climate are not well understood, limiting our ability to predict future global soil respiration rates. As part of a climate manipulation experiment, we tested whether differences in soil heterotrophic respiration (RH) driven by season or climate treatment are linked to (1) relative abundances of microbes in active and dormant metabolic states, (2) net changes in microbial biomass and/or (3) changes in the relative abundances of microbial groups with different C-use strategies. We used a flow-cytometric single-cell metabolic assay to quantify the abundance of active and dormant microbes, and the phospholipid fatty acid method to determine microbial biomass and ratios of fungi:bacteria and Gram-positive:Gram-negative bacteria. RH did not respond to climate treatments but was greater in the warm and dry summer than in the cool and less-dry fall. These dynamics were better explained when microbial data were taken into account compared to when only physical data (temperature and moisture) were used. Overall, our results suggest that RH responses to temperature are stronger when soil contains more active microbes, and that seasonal patterns of RH can be better explained by shifts in microbial activity than by shifts in the relative abundances of fungi and Gram-positive and Gram-negative bacteria. These findings contribute to our understanding of how and under which conditions microbes influence soil C responses to climate.
Preparation of Cyclohexenones from Acyclic (Pentadienyl)iron(1+) Cations: Synthetic Studies Directed toward the A-Ring of Dihydrotachysterols

The reaction of tricarbonyl(3-methylpentadienyl)iron(1+) cation (7) with stabilized carbon nucleophiles affords 4-methyl-5-substituted cyclohexenones. Reaction of 7 with sodium bis[(+)-2-phenylcyclohexyl]malonate afforded a mixture of diastereomers (de = 60 %); the diastereomeric allylic alcohols resulting from Luche reduction of this mixture were separable by column chromatography. Issues in diastereoselectivity in approaches to synthons for the A-ring of the tachysterols from these cyclohexenones are reported.
Childcare providers’ attitudes, knowledge, and practice related to developmental monitoring to promote early identification and referral

ABSTRACTAlthough intervening early can improve child and family outcomes when a child has a developmental disability, most children with developmental delays are not identified prior to school entr...
N-Substituted 2-Amino-4-pentenoic Acids for Amino Acid Protection and Resolution

Abstract N-Substituted 2-amino-4-pentenoic acid derivatives employed for the protection of racemic amino acids were shown to be capable of permitting the chromatographic separation of R and S isomers. When Nα was disubstituted with benzyl and phenylfluorenyl groups, the racemic amino acids could be separated with facility on open silica gel columns. Further, the optically pure N-protected amino acids so derived could be used for the preparation of misacylated suppressor transfer RNAs.
Phosphonic acid catalyzed synthesis of pyrazolidines

Abstract A phosphonic acid catalyst has been shown to promote the intramolecular cyclization of acylhydrazone 1. The resulting heterocyclic products, pyrazolidines, were isolated in good yield for a variety of acylhydrazones. Studies into the role of the phosphonic acid are presented and discussed.
Magnesium trifluoromethanesulfonimide(triflimide) promoted substitution reactions of allylic and benzylic acetates. Magnesium triflimide as a substitute for magnesium perchlorate

Abstract Magnesium triflimide(10 mol% in methylene chloride) is a convenient catalyst for the nucleophilic substitution of allylic and benzylic acetates, and constitutes a useful alternative to magnesium perchlorate.
SYNTHESIS OF C2-SYMMETRICAL POLYHYDROXYAZEPANES AS INHIBITORS OF GLYCOSIDASES

Abstract Two C2-symmetrical bis-epoxides were prepared from D - mannitol and were subjected to nucleophilic displacements with allylamine and benzylamine. Initial intermolecular epoxide opening, followed by a preferred intramolecular 7-endo-tetragol cyclization, afforded protected polyhydroxyazepanes as major products. Compound 15 was found to inhibit seven different glycosidases with Ki in the micromolar range.
Characterizing and interpreting the influence of internal variables on sensory activity

The concept of a tuning curve has been central for our understanding of how the responses of cortical neurons depend on external stimuli. Here, we describe how the influence of unobserved internal variables on sensory responses, in particular correlated neural variability, can be understood in a similar framework. We suggest that this will lead to deeper insights into the relationship between stimulus, sensory responses, and behavior. We review related recent work and discuss its implication for distinguishing feedforward from feedback influences on sensory responses, and for the information contained in those responses.
CORRELATION OF ELECTRONIC EFFECTS IN N-ALKYLNICOTINAMIDES WITH NMR CHEMICAL SHIFTS AND HYDRIDE TRANSFER REACTIVITY

The 13C and 15N NMR chemical shifts for ring atoms of a series of N-alkylnicotinamides are shown to be correlated with their reduction potentials and reactivities toward NaBH3CN. The nicotinamide compounds include N-ethyl-N-benzyl-N-[p-(trifluoromethyl)benzyl]-, N-(p-cyanobenzyl)-, N-(carbomethoxymethyl)-, and N-(cyanomethyl)nicotinamides. The values of δ13C for all the ring carbons increase with increasing electron-withdrawing power of the N-alkyl substituent. The value for C-4 increases the most, a range of 2.4 ppm in this series, whereas those for other atoms increase on the order of 1 ppm. The value of δ15N for N-1 decreases with increasing electron-withdrawing power over a range of 20 ppm. The NMR data indicate that inductive electron withdrawal by N-alkyl substituents polarizes the π-electron system to decrease electron density on ring carbons and increase electron density on the ring nitrogen. The values of log k (second order) for reduction of these compounds by NaBH3CN are proportional to the val...
Low-Temperature Matrix Isolation and Photolysis of BCl2N3: Spectroscopic Identification of the Photolysis Product ClBNCl

BCl2N3 was isolated in a low-temperature argon matrix, and its FTIR spectrum was measured. Ab initio calculations were carried out to support the identification of the IR spectrum, and splitting due to the natural abundances of 10B and 11B was observed. The experimental infrared frequencies and assignments are as follows: 2170 cm-1, the N3 asymmetric stretch; 1350 cm-1, the BN stretch; 1053 cm-1, the N3 symmetric stretch; 968 cm-1, the BCl stretch. Upon UV photolysis, the BCl2N3 peaks decreased and new peaks at 2034 and 2087 cm-1 with relative integrated intensities of 4:1 appeared. Ab initio calculations were carried out and support the assignment of these features to the BN stretches in the 10B and 11B isotopomers of ClBNCl. This intermediate is consistent with the photolytic intermediate generated during the photolysis of B(N3)3, and the photolytic mechanism is discussed.