cssi/SciSciGPT-SciSciNet huggingface dataset:
Alcohol exposure decreases osteopontin expression during fracture healing and osteopontin-mediated mesenchymal stem cell migration in vitro

Alcohol consumption is a risk factor for impaired fracture healing, though the mechanism(s) by which this occurs are not well understood. Our laboratory has previously shown that episodic alcohol exposure of rodents negatively affects fracture callus development, callus biomechanics, and cellular signaling which regulates stem cell differentiation. Here, we examine whether alcohol alters chemokine expression and/or signaling activity in the mouse fracture callus during early fracture healing. A mouse model for alcohol-impaired tibia fracture healing was utilized. Early fracture callus was examined for alcohol-effects on tissue composition, expression of chemokines involved in MSC migration to the fracture site, and biomechanics. The effects of alcohol on MSC migration and cell adhesion receptors were examined in an in vitro system. Mice exposed to alcohol showed decreased evidence of external callus formation, decreased callus-related osteopontin (OPN) expression levels, and decreased biomechanical stiffness. Alcohol exposure decreased rOPN-mediated MSC migration and integrin β1 receptor expression in vitro. The effects of alcohol exposure demonstrated here on fracture callus-associated OPN expression, rOPN-mediated MSC migration in vitro, and MSC integrin β1 receptor expression in vitro have not been previously reported. Understanding the effects of alcohol exposure on the early stages of fracture repair may allow timely initiation of treatment to mitigate the long-term complications of delayed healing and/or fracture non-union.
Higher-Order Inter-chromosomal Hubs Shape 3D Genome Organization in the Nucleus

Eukaryotic genomes are packaged into a 3-dimensional structure in the nucleus. Current methods for studying genome-wide structure are based on proximity ligation. However, this approach can fail to detect known structures, such as interactions with nuclear bodies, because these DNA regions can be too far apart to directly ligate. Accordingly, our overall understanding of genome organization remains incomplete. Here, we develop split-pool recognition of interactions by tag extension (SPRITE), a method that enables genome-wide detection of higher-order interactions within the nucleus. Using SPRITE, we recapitulate known structures identified by proximity ligation and identify additional interactions occurring across larger distances, including two hubs of inter-chromosomal interactions that are arranged around the nucleolus and nuclear speckles. We show that a substantial fraction of the genome exhibits preferential organization relative to these nuclear bodies. Our results generate a global model whereby nuclear bodies act as inter-chromosomal hubs that shape the overall packaging of DNA in the nucleus.
Inclusive Innovation: Product Innovation in Technology Supply Chains

Problem definition: Managers introducing new innovative technological products frequently face the dual task of managing both revenues and profits. This task is made challenging in part because of ...
Biochemical processing of heavy oils and residuum

During the past several decades, the petroleum industry has adjusted gradually to accommodate the changes in market product demands, government regulations, and the quality and cost of feedstock crude oils. For example, the trends show that the demand for distillate fuels, such as diesel, as compared to gasoline are increasing. Air-quality standards have put additional demand on the processing of heavier and higher sulfur feed stocks. Thus, the 1990 Clean Air Act amendments require the industry to produce greater quantities of oxygenated gasoline, and lower sulfur diesel and reformulated gasoline. Biochemical technology may play an important role in responding to these demands on the petroleum industry. Since oil is of biological origin, some biochemical reactions started at the beginning of its formation are still continuing in reservoirs on a geological time scale. Although these rates are very slow, many reactions can proceed readily under optimal conditions. This article will address some of the reactions that may be useful for processing heavy oils and refinery residuum. 6 refs., 2 figs., 3 tabs.
Modeling and Analysis of Cascading Failures in Interdependent Cyber-Physical Systems

Integrated cyber-physical systems (CPSs), such as the smart grid, are becoming the underpinning technology for major industries. A major concern regarding such systems are the seemingly unexpected large scale failures, which are often attributed to a small initial shock getting escalated due to intricate dependencies within and across the individual counterparts of the system. In this paper, we develop a novel interdependent system model to capture this phenomenon, also known as cascading failures. Our framework consists of two networks that have inherently different characteristics governing their intra-dependency: i) a cyber-network where a node is deemed to be functional as long as it belongs to the largest connected (i.e., giant) component; and ii) a physical network where nodes are given an initial flow and a capacity, and failure of a node results with redistribution of its flow to the remaining nodes, upon which further failures might take place due to overloading. Furthermore, it is assumed that these two networks are inter-dependent. For simplicity, we consider a one-to-one interdependency model where every node in the cyber-network is dependent upon and supports a single node in the physical network, and vice versa. We provide a thorough analysis of the dynamics of cascading failures in this interdependent system initiated with a random attack. The system robustness is quantified as the surviving fraction of nodes at the end of cascading failures, and is derived in terms of all network parameters involved. Analytic results are supported through an extensive numerical study. Among other things, these results demonstrate the ability of our model to capture the unexpected nature of large-scale failures, and provide insights on improving system robustness.
You get what you give: theory and evidence of reciprocity in the sharing economy

We develop an analytical framework of peer interaction in the sharing economy that incorporates reciprocity, the tendency to increase (decrease) effort in response to others’ increased (decreased) effort. In our model, buyers (sellers) can induce sellers (buyers) to exert more effort by behaving well themselves. We demonstrate that this joint increased effort can improve the utility of both parties and influence the market equilibrium. We also show that bilateral reputation systems, which allow both buyers and sellers to review each other, are more responsive to reciprocity than unilateral reputation systems. By rewarding reciprocal behavior, bilateral reputation systems generate trust among strangers and informally regulate their behavior. We test the predictions of our model using data from Airbnb, a popular peer-to-peer accommodation platform. We show that Airbnb hosts that are more reciprocal receive higher ratings and that higher rated hosts can increase their prices. Therefore, reciprocity affects equilibrium prices on Airbnb through its impact on ratings, as predicted by our analytical framework.
Improving Generalization via Scalable Neighborhood Component Analysis

Current major approaches to visual recognition follow an end-to-end formulation that classifies an input image into one of the pre-determined set of semantic categories. Parametric softmax classifiers are a common choice for such a closed world with fixed categories, especially when big labeled data is available during training. However, this becomes problematic for open-set scenarios where new categories are encountered with very few examples for learning a generalizable parametric classifier. We adopt a non-parametric approach for visual recognition by optimizing feature embeddings instead of parametric classifiers. We use a deep neural network to learn the visual feature that preserves the neighborhood structure in the semantic space, based on the Neighborhood Component Analysis (NCA) criterion. Limited by its computational bottlenecks, we devise a mechanism to use augmented memory to scale NCA for large datasets and very deep networks. Our experiments deliver not only remarkable performance on ImageNet classification for such a simple non-parametric method, but most importantly a more generalizable feature representation for sub-category discovery and few-shot recognition.
Pericentromeric hypomethylation elicits an interferon response in an animal model of ICF syndrome

Cells package DNA into structures called chromosomes. When cells divide, each chromosome duplicates, and a structure called a centromere initially holds the copies together. The sequences of DNA on either side of the centromeres are often highly repetitive. In backboned animals, this DNA normally also has extra chemical modifications called methyl groups attached to it. The role that these methyl groups play in this region is not known, although in other DNA regions they often stop the DNA being ‘transcribed’ into molecules of RNA. The cells of people who have a rare human genetic disorder called ICF syndrome, lack the methyl groups near the centromere. The methyl groups may also be lost in old and cancerous cells. Researchers often use ‘model’ animals to investigate the effects of DNA modifications. But, until now, there were no animal models that lose methyl groups from the DNA around centromeres in the same way as seen in ICF syndrome. Rajshekar et al. have developed a new zebrafish model for ICF syndrome that loses the methyl groups around its centromeres over time. Studying the cells of these zebrafish showed that when the methyl groups are missing, the cell starts to transcribe the DNA sequences around the centromeres. The resulting RNA molecules appear to be mistaken by the cell for viral RNA. They activate immune sensors that normally detect RNA viruses, which triggers an immune response. The new zebrafish model can now be used in further studies to help researchers to understand the key features of ICF syndrome. Future work could also investigate whether the loss of methyl groups around the centromeres plays a role in other diseases where the immune system attacks healthy tissues.
Tight Proofs of Space and Replication

We construct a concretely practical proof-of-space (PoS) with arbitrarily tight security based on stacked depth robust graphs and constant-degree expander graphs. A proof-of-space (PoS) is an interactive proof system where a prover demonstrates that it is persistently using space to store information. A PoS is arbitrarily tight if the honest prover uses exactly N space and for any \(\epsilon > 0\) the construction can be tuned such that no adversary can pass verification using less than \((1-\epsilon ) N\) space. Most notably, the degree of the graphs in our construction are independent of \(\epsilon \), and the number of layers is only \(O(\log (1/\epsilon ))\). The proof size is \(O(d/\epsilon )\). The degree d depends on the depth robust graphs, which are only required to maintain \(\varOmega (N)\) depth in subgraphs on 80% of the nodes. Our tight PoS is also secure against parallel attacks.
The maximum size of \((k,l)\)-sum-free sets in cyclic groups

A subset -sum-free subset of an abelian group’, Int. J. Number Theory 5(6) (2009), 953–971].
Accelerating Beam Sweeping in mmWave Standalone 5G New Radios Using Recurrent Neural Networks

Millimeter wave (mmWave) is a key technology to support high data rate demands for 5G applications. Highly directional transmissions are crucial at these frequencies to compensate for high isotropic pathloss. This reliance on directional beamforming, however, makes the cell discovery (cell search) challenging since both base station (gNB) and user equipment (UE) jointly perform a search over angular space to locate potential beams to initiate communication. In the cell discovery phase, sequential beam sweeping is performed through the angular coverage region in order to transmit synchronization signals. The sweeping pattern can either be a linear rotation or a hopping pattern that makes use of additional information. This paper proposes beam sweeping pattern prediction, based on the dynamic distribution of user traffic, using a form of recurrent neural networks (RNNs) called Gated Recurrent Unit (GRU). The spatial distribution of users is inferred from data in call detail records (CDRs) of the cellular network. Results show that the users spatial distribution and their approximate location (direction) can be accurately predicted based on CDRs data using GRU, which is then used to calculate the sweeping pattern in the angular domain during cell search.
Resilient Computing with Reinforcement Learning on a Dynamical System: Case Study in Sorting

This paper formulates general computation as a feedback-control problem, which allows the agent to autonomously overcome some limitations of standard procedural language programming: resilience to errors and early program termination. Our formulation considers computation to be trajectory generation in the program's variable space. The computing then becomes a sequential decision making problem, solved with reinforcement learning (RL), and analyzed with Lyapunov stability theory to assess the agent's resilience and progression to the goal. We do this through a case study on a quintessential computer science problem, array sorting. Evaluations show that our RL sorting agent makes steady progress to an asymptotically stable goal, is resilient to faulty components, and performs less array manipulations than traditional Quicksort and Bubble sort.
Lymphoproliferation in CTLA-4-deficient mice is mediated by costimulation-dependent activation of CD4+ T cells

Abstract CTLA-4–deficient animals develop a fatal lymphoproliferative disorder. The cellular mechanism(s) responsible for this phenotype have not been determined. Here, we show that there is a preferential expansion of CD4 + T cells in CTLA-4 −/− mice, which results in a skewing of the CD4/CD8 T cell ratio. In vivo antibody depletion of CD8 + T cells from birth does not alter the onset or the severity of the CD28-dependent lymphoproliferative disorder. In contrast, CD4 + T cell depletion completely prevents all features characteristic of the lymphoproliferation observed in CTLA-4–deficient mice. These results demonstrate that CD4 + T cells initiate the phenotype in the CTLA-4 −/− mice. Further, these results suggest that the role of CTLA-4 in peripheral CD4 + versus CD8 + T cell homeostasis is distinct.
Nucleus Reuniens Is Required for Encoding and Retrieving Precise, Hippocampal-Dependent Contextual Fear Memories in Rats

The nucleus reuniens (RE) is a ventral midline thalamic nucleus that interconnects the medial prefrontal cortex (mPFC) and hippocampus (HPC). Considerable data indicate that HPC-mPFC circuits are involved in contextual and spatial memory; however, it is not clear whether the RE mediates the acquisition or retrieval of these memories. To examine this question, we inactivated the RE with muscimol before either the acquisition or retrieval of pavlovian fear conditioning in rats; freezing served as the index of fear. We found that RE inactivation before conditioning impaired the acquisition of contextual freezing, whereas inactivation of the RE before retrieval testing increased the generalization of freezing to a novel context; inactivation of the RE did not affect either the acquisition or expression of auditory fear conditioning. Interestingly, contextual conditioning impairments were absent when retrieval testing was also conducted after RE inactivation. Contextual memories acquired under RE inactivation were hippocampal independent, insofar as contextual freezing in rats conditioned under RE inactivation was insensitive to intrahippocampal infusions of the NMDA receptor antagonist aminophosphonovalerate. Together, these data reveal that the RE supports hippocampal-dependent encoding of precise contextual memories that allow discrimination of dangerous contexts from safe contexts. When the RE is inactive, however, alternate neural systems acquire an impoverished contextual memory that is expressed only when the RE is off-line.SIGNIFICANCE STATEMENT The midline thalamic nucleus reuniens (RE) coordinates communication between the hippocampus and medial prefrontal cortex, brain areas that are critical for contextual and spatial memory. Here we show that temporary pharmacological inactivation of RE impairs the acquisition and precision of contextual fear memories after pavlovian fear conditioning in rats. However, inactivating the RE before retrieval testing restored contextual memory in rats conditioned after RE inactivation. Critically, we show that imprecise contextual memories acquired under RE inactivation are learned independently of the hippocampus. These data reveal that the RE is required for hippocampal-dependent encoding of precise contextual memories to support the discrimination of safe and dangerous contexts.
Living Life : Assessing Bureaucratic Complexity in Citizen-Government Interactions

Bureaucratic complexity in citizen-government interactions can be an obstacle to accessing basic services and exercising civil rights. This paper presents a methodology to collect contributor-based data on the regulatory framework and compliance burden of six key citizen-government interactions: (i) civil registration and identification, (ii) voting, (iii) paying taxes, (iv) access to health care, (v) access to education, and (vi) access to utilities. The methodology was tested in Chile, Ghana, India, and Vietnam, and it provided an overview of the legal and regulatory frameworks. In addition, the study offers some interesting observations: (i) two of the four economies moved toward including digital components to civil registration and identification systems, making it easier to register births/deaths and obtain an identification document; (ii) three of the four economies require a specific voter ID to cast a ballot, which can discourage citizens from engaging in elections; (iii) patients accessing certain services at primary health care facilities may experience longer waits for treatment than those seeking access to the same services in hospitals; and (iv) a student’s ability to access quality education can be limited by school placement based on residential address in two of the four economies. The lessons learned suggest that future studies should use survey data collection to investigate the practical experience of citizens beyond procedures and legal requirements. In addition, focusing on fewer areas and including a larger set of countries could generate greater variability and more robust conclusions.
Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions

The conventional Landau-Lifshitz-Gilbert (LLG) equation is a widely used tool to describe the dynamics of local magnetic moments, viewed as classical vectors of fixed length, with their change assumed to take place simultaneously with the cause. Here we demonstrate that recently developed [M. D. Petrovi\ifmmode \acute{c}\else \'{c}\fi{} et al., Phys. Rev. Appl. 10, 054038 (2018)] self-consistent coupling of the LLG equation to a time-dependent quantum-mechanical description of electrons---where nonequilibrium spin density from time-dependent nonequilibrium Green function (TDNEGF) calculations is inserted within a torque term into the LLG equation while local magnetic moments evolved by the LLG equation introduce time-dependent potential in the quantum Hamiltonian of electrons---microscopically generates time-retarded damping in the LLG equation described by a memory kernel that is also spatially dependent. For sufficiently slow dynamics of local magnetic moments on the memory time scale, the kernel can be expanded into power series to extract the Gilbert damping (proportional to the first time derivative of magnetization) and magnetic inertia (proportional to the second time derivative of magnetization) terms whose parameters, however, are time-dependent in contrast to time-independent parameters used in the conventional LLG equation. We use examples of single or multiple local magnetic moments precessing in an external magnetic field, as well as field-driven motion of a magnetic domain wall (DW), to quantify the difference in their time evolution computed from the conventional LLG equation versus the TDNEGF+LLG quantum-classical hybrid approach. The faster DW motion predicted by the TDNEGF+LLG approach reveals that important quantum effects, stemming essentially from a finite amount of time that it takes for a conduction electron spin to react to the motion of classical local magnetic moments, are missing from conventional classical micromagnetics simulations. We also demonstrate a large discrepancy between the TDNEGF+LLG-computed numerically exact and, therefore, nonperturbative result for charge current pumped by a moving DW and the same quantity computed by a perturbative spin motive force formula combined with the conventional LLG equation.
Analysis of sport sales courses in the sport management curriculum.

Abstract This paper examined the curriculum posted on program websites of sales education in undergraduate sport management programs in the United States. A sport sales course is offered by 22% of undergraduate sport management programs. Programs with Commission on Sport Management Accreditation (COSMA) accreditation, located in a city, housed in a sport management or leisure department, and programs with larger student enrollments were the most likely to offer a sport sales course. A survey was also utilized better understand of how sport sales courses are being taught and uncover the perceptions of programs not offering sales. The top reasons for adding the class were the demand from the industry for qualified salespeople and a positive employment outlook. Survey results revealed that all courses were taught in a face-to-face environment with an average class size of 27, predominantly taught by a full-time faculty member in sport management. Selling in the Sport Industry authored by Pierce et al. was the most commonly used textbook. Respondents from programs not offering the course nearly universally recognized the importance of students demonstrating competence in sales by the time they graduate, and 74% reported covering sales competencies elsewhere in curriculum. Slightly over one-fourth of the programs without a sales course indicated that addition of a required class is likely in the near future. The business school was a likely place to outsource the teaching of sales competencies, with 13% of schools without a sport sales class requiring a professional selling course offered in the business school and 18% offering access to an elective. The most significant obstacle impeding the adoption of sales was the constraint posed by credit hour limits for graduation.
Detecting Edges from Non-uniform Fourier Data via Sparse Bayesian Learning

In recent investigations, the problem of detecting edges given non-uniform Fourier data was reformulated as a sparse signal recovery problem with an $$\ell _1$$ -regularized least squares cost function. This result can also be derived by employing a Bayesian formulation. Specifically, reconstruction of an edge map using $$\ell _1$$ regularization corresponds to a so-called type-I (maximum a posteriori) Bayesian estimate. In this paper, we use the Bayesian framework to design an improved algorithm for detecting edges from non-uniform Fourier data. In particular, we employ what is known as type-II Bayesian estimation, specifically a method called sparse Bayesian learning. We also show that our new edge detection method can be used to improve downstream processes that rely on accurate edge information like image reconstruction, especially with regards to compressed sensing techniques.
The spectral gap for transfer operators of torus extensions over expanding maps

We study the spectral gap for transfer operators of the skew product $F: \mathbb{T}^d\times \mathbb{T}^\ell\to \mathbb{T}^d\times \mathbb{T}^\ell$ given by $F(x,y)=(Tx, y+\tau(x) \pmod{ \mathbb{Z}^\ell})$, where $T: \mathbb{T}^d\to \mathbb{T}^d$ is a $C^\infty$ uniformly expanding endomorphism, and the fiber map $\tau: \mathbb{T}^d\to \mathbb{R}^\ell$ is a $C^\infty$ map. We construct a Hilbert space $\mathcal{W}^{-s}$ for any $s<0$, which contains all the Holder functions of Holder exponents $|s|$ on $ \mathbb{T}^d\times \mathbb{T}^\ell$. Applying the method of semiclassical analysis, we obtain the dichotomy: either the transfer operator has a spectral gap on $\mathcal{W}^{-s}$, or $\tau$ is an essential coboundary. In the former case, $F$ mixes exponentially fast for Holder observables with Holder exponents $|s|$; and in the latter case, either $F$ is not weak mixing and it is semiconjugate to a circle rotation, or $F$ is unstably mixing, i.e., it can be approximated by non-mixing skew products.
Chapter 10 – Analysis and Valuation of Privately Held Firms

This chapter discusses in detail the hazards of dealing with both limited and often unreliable data associated with private firms. It then focuses on how to properly adjust questionable data as well as how to select the appropriate valuation methodology and discount or capitalization rate. Considerable time is spent discussing how to apply control premiums, minority discounts, and liquidity discounts in valuing businesses. This chapter also includes a discussion of how corporate shells created through reverse mergers and leveraged employee stock ownership plans are used to acquire privately owned companies and how private investment in public equity (PIPE) financing may be used to fund their ongoing operations.
The multiple flying sidekicks traveling salesman problem: Parcel delivery with multiple drones

Abstract This paper considers a last-mile delivery system in which a delivery truck operates in coordination with a fleet of unmanned aerial vehicles (UAVs, or drones). Deploying UAVs from the truck enables customers located further from the depot to receive drone-based deliveries. The problem is first formulated as a mixed integer linear program (MILP). However, owing to the computational complexity of this problem, only trivially-sized problems may be solved directly via the MILP. Thus, a heuristic solution approach that consists of solving a sequence of three subproblems is proposed. Extensive numerical testing demonstrates that this approach effectively solves problems of practical size within reasonable runtimes. Additional analysis quantifies the potential time savings associated with employing multiple UAVs. The analysis also reveals that additional UAVs may have diminishing marginal returns. An analysis of five different endurance models demonstrates the effects of these models on UAV assignments. The model and heuristic also support anticipated future systems that feature automation for UAV launch and retrieval.
Coordination of Autonomous Healthcare Entities: Emergency Response to Multiple Casualty Incidents

In recent years, many urban areas have established healthcare coalitions composed of autonomous (and often competing) hospitals, with the goal of improving emergency preparedness and response. We study the role of such coalitions in the specific context of response to multiple-casualty incidents in an urban setting, where on-scene responders must determine how to send casualties to medical facilities. A key function in incident response is multi-agency coordination. When this coordination is provided by a healthcare coalition, responders can use richer information about hospital capacities to decide where to send casualties. Using bed availability data from an urban area and a suburban area in the United States, we analyze the response capability of healthcare infrastructures under different levels of coordination, and we develop a stress test to identify areas of weakness. We find that improved coordination efforts should focus on decision support using information about inpatient resources, especially in urban areas with high inter-hospital variability in resource availability. We also find that coordination has the largest benefit in small incidents. This benefit is a new value proposition for healthcare coalitions, which were originally formed to improve preparedness for large disasters. This article is protected by copyright. All rights reserved.
Vancomycin-Associated Acute Kidney Injury in Critically Ill Adolescent and Young Adult Patients:

Background:Risk factors for the development of vancomycin-associated acute kidney injury (AKI) have been evaluated in both pediatric and adult populations; however, no previous studies exist evalua...
Modeling Mobile Interface Tappability Using Crowdsourcing and Deep Learning

Tapping is an immensely important gesture in mobile touchscreen interfaces, yet people still frequently are required to learn which elements are tappable through trial and error. Predicting human behavior for this everyday gesture can help mobile app designers understand an important aspect of the usability of their apps without having to run a user study. In this paper, we present an approach for modeling tappability of mobile interfaces at scale. We conducted large-scale data collection of interface tappability over a rich set of mobile apps using crowdsourcing and computationally investigated a variety of signifiers that people use to distinguish tappable versus not-tappable elements. Based on the dataset, we developed and trained a deep neural network that predicts how likely a user will perceive an interface element as tappable versus not tappable. Using the trained tappability model, we developed TapShoe, a tool that automatically diagnoses mismatches between the tappability of each element as perceived by a human user---predicted by our model, and the intended or actual tappable state of the element specified by the developer or designer. Our model achieved reasonable accuracy: mean precision 90.2% and recall 87.0%, in matching human perception on identifying tappable UI elements. The tappability model and TapShoe were well received by designers via an informal evaluation with 7 professional interaction designers.
A simple approximation for evaluating external validity bias

Abstract We develop a simple approximation that relates the total external validity bias in randomized trials to (i) bias from selection on observables and (ii) a measure for the role of treatment effect heterogeneity in driving selection into the experimental sample.
Quantifying and reducing execution variance in STM via model driven commit optimization

Simplified parallel programming coupled with an ability to express speculative computation is realized with Software Transactional Memory (STM). Although STMs are gaining popularity because of significant improvements in parallel performance, they exhibit enormous variation in transaction execution with non-repeatable performance behavior which is unacceptable in many application domains, especially in which frame rates and responsiveness should be predictable. In other domains reproducible transactional behavior helps towards system provisioning. Thus, reducing execution variance in STM is an important performance goal that has been mostly overlooked. In this work, we minimize the variance in execution time of threads in STM by reducing non-determinism exhibited due to speculation. We define the state of STM, and we use it to first quantity non-determinism and then generate an automaton that models the execution behavior of threads in STM. We finally use the state automaton to guide the STM to avoid non-predictable transactional behavior thus reducing non-determinism in roll-backs which in turn results in reduction in variance. We observed average reduction of variance in execution time of threads up to 74% in 16 cores and 53% in 8 cores by reducing non-determinism up to 24% in 16 cores and 44% in 8 cores, respectively, on STAMP benchmark suite while experiencing average slowdown of 4.8% in 8 cores and 19.2% in 16 cores. We also reduced the variance in frame rate by maximum of 65% on a version of real world game Quake3 without degradation in timing.
A Hierarchical Optimization Architecture for Large-Scale Power Networks

We present a hierarchical optimization architecture for large-scale power networks that overcomes limitations of fully centralized and fully decentralized architectures. The architecture leverages principles of multigrid computing schemes, which are widely used in the solution of partial differential equations on massively parallel computers. The top layer of the architecture uses a coarse representation of the entire network, whereas the bottom layer is composed of a family of decentralized optimization agents each operating on a network subdomain at full resolution. We use an alternating direction method of multipliers (ADMM) framework to drive coordination of the decentralized agents. We show that state and dual information obtained from the top layer can be used to accelerate the coordination of the decentralized optimization agents and to recover optimality for the entire system. We demonstrate that the hierarchical architecture can be used to manage large collections of microgrids.
Negative Differential Conductivity in AlGaN/GaN HEMTs: Real Space Charge Transfer from 2D to 3D GaN States?

We report on non-thermal negative differential conductivity (NDC) in AlGaN/GaN HEMTs grown on sapphire substrates by low-pressure MOCVD. The sheet electron density was on the order of few times 1012cm−2 and the Hall mobility was 1,000 cm2/V.s. The HEMTs had threshold voltage close to zero and could operate at high positive gate bias up to 3 to 3.5 Volts, with a very low gate leakage current. NDC was observed at the gate bias larger than 1.5V and at the drain biases between approximately 0.5Vg and Vg. We excluded the possibility of self-heating as the cause, since the NDC occurs at relatively small power levels where self-heating effects are negligible.An explanation we provided for the NDC effect is the new mechanism of real space charge transfer from 2D to 3D GaN states, which leads to a decrease in the channel mobility at large 2D electron gas densities. The observed low leakage can be explained by an enhanced molar fraction of aluminum at the heterointerface that results in a larger conduction band discontinuity. Our model that accounts for the piezoelectric and pyroelectric effects is consistent with the observed NDC effect. The Hall mobility dependence on the gate bias and sheet carrier concentration [1] is consistent with the real space transfer mechanism.This NDC effect in GaN/AlGaN HEMTs may find applications in high-performance digital circuits at elevated temperatures.
Zwitterionic poly-carboxybetaine coating reduces artificial lung thrombosis in sheep and rabbits

Abstract Current artificial lungs fail in 1–4 weeks due to surface-induced thrombosis. Biomaterial coatings may be applied to anticoagulate artificial surfaces, but none have shown marked long-term effectiveness. Poly-carboxybetaine (pCB) coatings have shown promising results in reducing protein and platelet-fouling in vitro. However, in vivo hemocompatibility remains to be investigated. Thus, three different pCB-grafting approaches to artificial lung surfaces were first investigated: 1) graft-to approach using 3,4-dihydroxyphenylalanine (DOPA) conjugated with pCB (DOPA-pCB); 2) graft-from approach using the Activators ReGenerated by Electron Transfer method of atom transfer radical polymerization (ARGET-ATRP); and 3) graft-to approach using pCB randomly copolymerized with hydrophobic moieties. One device coated with each of these methods and one uncoated device were attached in parallel within a veno-venous sheep extracorporeal circuit with no continuous anticoagulation (N = 5 circuits). The DOPA-pCB approach showed the least increase in blood flow resistance and the lowest incidence of device failure over 36-hours. Next, we further investigated the impact of tip-to-tip DOPA-pCB coating in a 4-hour rabbit study with veno-venous micro-artificial lung circuit at a higher activated clotting time of 220–300 s (N ≥ 5). Here, DOPA-pCB reduced fibrin formation (p = 0.06) and gross thrombus formation by 59% (p Statement of Significance Chronic lung diseases lead to 168,000 deaths each year in America, but only 2300 lung transplantations happen each year. Hollow fiber membrane oxygenators are clinically used as artificial lungs to provide respiratory support for patients, but their long-term viability is hindered by surface-induced clot formation that leads to premature device failure. Among different coatings investigated for blood-contacting applications, poly-carboxybetaine (pCB) coatings have shown remarkable reduction in protein adsorption in vitro. However, their efficacy in vivo remains unclear. This is the first work that investigates various pCB-coating methods on artificial lung surfaces and their biocompatibility in sheep and rabbit studies. This work highlights the promise of applying pCB coatings on artificial lungs to extend its durability and enable long-term respiratory support for lung disease patients.
Bioethics of military performance enhancement

Biological interventions to improve performance, such as amphetamines, have a long history of military use, and in the future may include more advanced biotechnologies. This article discusses the ethics of using biomedical enhancements in the military. The article begins by describing the distinction between biomedical enhancements and interventions intended to prevent, treat or mitigate disease. It then sets forth three principles to guide the ethical use of bioenhancements—proportionality, paternalism and fairness. The article applies these principles to concerns raised by military bioenhancement: safety, fairness in access to military reward, carryover effects to civilian life, whether service members can be ordered to use bioenhancements and when they may be permitted to do so voluntarily.
On the Creation and Evolution of Small-Scale Low-Level Vorticity Anomalies during Tropical Cyclogenesis

AbstractRecent numerical modeling and observational studies indicate the importance of vortical hot towers (VHTs) in the transformation of a tropical disturbance to a tropical depression. It has re...
Ruthenium-Catalyzed Demethanative Coupling of HGeMe3: A High Yield Route to Polygermanes

We now report an efficient catalytic process for preparing permethyl polygermanes in high yields from trimethylgermanes. This appears to be the first example of a catalytic demethanative coupling, in which element-element bonds are produced with the concurrent elimination of CH{sub 4}. The catalytic cycle can lead to either linear or branched polygermanes. The structure of the polymer will be influenced by the site of the {alpha}-Me migration: either a GeMe{sub 3} or an oligogermyl (GeMe{sub 2}GeMe{sub 2}R) group. Interconversion via 1,3-migration in the germyl-germylene complex could also lead to branching. Related redistributions of alkyl groups in bis-(silyl) and mixed germyl silyl systems have been observed and are thought to proceed via 1,3-migrations of substituents in intermediate silylene (or germylene) complexes. In summary, demethanative coupling of a tertiary germane produces nearly quantitative yields of highly branched, high molecular weight polygermanes under very mild conditions. 20 refs., 1 tab.
COPPER-CATALYZED CROSS-COUPLING OF ALKYLSAMARIUM REAGENTS WITH ALKYL HALIDES

Abstract SmI 2 /HMPA converts alkyl iodides and bromides to alkyl samarium reagents which can be cross-coupled with primary alkyl iodides and bromides and secondary iodides in the presence of Cu(I) halides or Li 2 CuCl 4 at room temperature. The alkylation of primary iodides gives good yields of cross-coupling products with negligible homo-coupling products. The method is especially useful for the small scale cross-coupling reactions.
INVESTIGATIONS OF A NUCLEOPHILIC ALANINOL SYNTHON DERIVED FROM SERINE

A nucleophilic synthon, (S)-(+)-4-(2-oxazolidonyl)-methyltriphenylphosphinyl iodide 6, available from l-serine in five steps (overall yield of 52%), reacts with aldehydes to produce alkenes in good to excellent yields (74−89%) and, in some cases, provides excellent stereocontrol of the new double bond. The geometry of the newly formed double bond is influenced by the nature of the aldehyde and reaction conditions. The trends in olefin configuration are discussed. Application of this methodology allows for easy preparation of molecules containing double bonds allylic to nitrogen, including oxazolidinones and β,γ-unsaturated amino alcohols. Several of the unsaturated oxazolidinones are converted to β,γ-unsaturated amino alcohols in high yields (75 to 90%).
Synthesis of benzoxepins via rearrangement of dihydrofurans derived from carbonyl ylide [3+2] cycloaddition

Abstract Highly substituted benzoxepins can be prepared via BBr 3 -induced rearrangement of functionalized dihydrofurans derived from carbonyl ylide [3+2] cycloaddition.
Dichotomy of cellular inhibition by small-molecule inhibitors revealed by single-cell analysis

Despite progress in drug development, a quantitative and physiological understanding of how small-molecule inhibitors act on cells is lacking. Here, we measure the signalling and proliferative response of individual primary T-lymphocytes to a combination of antigen, cytokine and drug. We uncover two distinct modes of signalling inhibition: digital inhibition (the activated fraction of cells diminishes upon drug treatment, but active cells appear unperturbed), versus analogue inhibition (the activated fraction is unperturbed whereas activation response is diminished). We introduce a computational model of the signalling cascade that accounts for such inhibition dichotomy, and test the model predictions for the phenotypic variability of cellular responses. Finally, we demonstrate that the digital/analogue dichotomy of cellular response as revealed on short (signal transduction) timescales, translates into similar dichotomy on longer (proliferation) timescales. Our single-cell analysis of drug action illustrates the strength of quantitative approaches to translate in vitro pharmacology into functionally relevant cellular settings.
Extended categorization of conjunction object stimuli decreases the latency of attentional feature selection and recruits orthography-linked ERPs.

Abstract The role of attention in driving perceptual expertise effects is controversial. The current study addressed the effect of training on ERP components related to and independent of attentional feature selection. Participants learned to categorize cartoon animals over six training sessions (8,800 trials) after which ERPs were recorded during a target detection task performed on trained and untrained stimulus sets. The onset of the selection negativity, an ERP component indexing attentional modulation, was about 60 msec earlier for trained than untrained stimuli. Trained stimuli also elicited centro-parietal N200 and N320 components that were insensitive to attentional feature selection. The scalp distribution and timecourse of these components were better matched by studies of orthography than object expertise. Source localization using eLORETA suggested that the strongest neural sources of the selection negativity were in right ventral temporal cortex whereas the strongest sources of the N200/N320 components were in left ventral temporal cortex, again consistent with the hypothesis that training recruited orthography related areas. Overall, training altered neural processes related to attentional selection, but also affected neural processes that were independent of feature selection.
ENANTIOSPECIFIC SYNTHESIS OF (+)- AND (-)-FERRUGININE FROM L-GLUTAMIC ACID. SYNTHESIS OF TROPANES VIA INTRAMOLECULAR IMINIUM ION CYCLIZATION

Iminium ions, generated by decarbonylation of N-benzyl-5-[1-(methoxycarbonyl)-4-oxopentyl]prolines, undergo intramolecular cyclization to afford 2,4-disubstituted tropanes in good yields. This transformation is also shown to be a stereospecific reaction. The value of these substituted tropanes has been demonstrated by functional group manipulation, leading to the enantiospecific synthesis of (+)-ferruginine, an alkaloid isolated from Darlinga ferruginea, and its unnatural enantiomer, (−)-ferruginine.
Demographic compensation does not rescue populations at a trailing range edge

Species’ geographic ranges and climatic niches are likely to be increasingly mismatched due to rapid climate change. If a species’ range and niche are out of equilibrium, then population performance should decrease from high-latitude “leading” range edges, where populations are expanding into recently ameliorated habitats, to low-latitude “trailing” range edges, where populations are contracting from newly unsuitable areas. Demographic compensation is a phenomenon whereby declines in some vital rates are offset by increases in others across time or space. In theory, demographic compensation could increase the range of environments over which populations can succeed and forestall range contraction at trailing edges. An outstanding question is whether range limits and range contractions reflect inadequate demographic compensation across environmental gradients, causing population declines at range edges. We collected demographic data from 32 populations of the scarlet monkeyflower (Erythranthe cardinalis) spanning 11° of latitude in western North America and used integral projection models to evaluate population dynamics and assess demographic compensation across the species’ range. During the 5-y study period, which included multiple years of severe drought and warming, population growth rates decreased from north to south, consistent with leading-trailing dynamics. Southern populations at the trailing range edge declined due to reduced survival, growth, and recruitment, despite compensatory increases in reproduction and faster life-history characteristics. These results suggest that demographic compensation may only delay population collapse without the return of more favorable conditions or the contribution of other buffering mechanisms such as evolutionary rescue.
Synthesis of 1‐ and 3‐arylcarbonyl derivatives of 5‐fluorouracil

4'-Substituted 1-arylcarbonyl-5-fluorouracil derivatives were synthesized from the reaction of the potassium salt of 5-fluorouracil with one equivalent of aryl acid chloride in acetonitrile. 4'-Substituted 3- arylcarbonyl-5-fluorouracil derivatives were synthesized from the reaction of 5-fluorouracil with 3 equivalents of the aryl acid chloride in pyridine and the subsequent hydrolysis of the 1,3-diarylcarbonyl-5-fluorouracil derivatives in situ with a small amount of water. If a large amount of water were used in the second step, the 1,3-diarylcarbonyl-5-fluorouracil precipitated before it hydrolyzed. The melting behaviors of both the 1- arylcarbonyl-5-fluorouracil and 3-arylcarbonyl-5-fluorouracil series suggested that thermal decomposition or rearrangement occurred on heating. The position of the C-H absorption in the H nmr spectra of l- arylcarbonyl-5-fluorouracils was 0.14 to 0.23 ppm farther downfield than that of the corresponding 3-arylcarbonyl-5-fluorouracils while that of the 1,3- diarylcarbonyl-5-fluorouracils was even farther downfield. The Rf values of 1-arylcarbonyl-5-fluorouracils were significantly greater (0.23 to 0.41) than those of the corresponding 3-arylcarbonyl-5-fluorouracils, while that of 1,3- diarylcarbonyl-5-fluorouracil was slightly greater than that of 1- arylcarbonyl-5-fluorouracils.
Electronic transport and magnetic properties of a new nickel antimonide telluride, Ni2SbTe2

Abstract The mixed anion compound, Ni2SbTe2, has been prepared from the elements in a potassium iodide flux. The crystal structure is solved in the hexagonal space group P63/mmc (no. 194) with lattice parameters a=b=3.9030(9) A and c=15.634(3) A. Sb and Te occupy crystallographically distinct anion sites within the crystal structure. The Seebeck coefficient, electrical resistivity, and magnetic susceptibility have been measured for the title compound, and shows typical metallic behavior. Extended Huckel band structure calculations also predict metallic behavior in bands dominated by Ni and Te orbital contributions.