cssi/SciSciGPT-SciSciNet huggingface dataset:
The Future is a Moving Target: Predicting Political Instability

Previous research by Goldstone et al. (2010) generated a highly accurate predictive model of state-level political instability. Notably, this model identifies political institutions – and partial democracy with factionalism, specifically – as the most compelling factors explaining when and where instability events are likely to occur. This article reassesses the model’s explanatory power and makes three related points: (1) the model’s predictive power varies substantially over time; (2) its predictive power peaked in the period used for out-of-sample validation (1995–2004) in the original study and (3) the model performs relatively poorly in the more recent period. The authors find that this decline is not simply due to the Arab Uprisings, instability events that occurred in autocracies. Similar issues are found with attempts to predict nonviolent uprisings (Chenoweth and Ulfelder 2017) and armed conflict onset and continuation (Hegre et al. 2013). These results inform two conclusions: (1) the drivers of instability are not constant over time and (2) care must be exercised in interpreting prediction exercises as evidence in favor or dispositive of theoretical mechanisms.
Analysis of the secrecy of the running key in quantum encryption channels using coherent states of light

Free-space optical communication channels offer secure links with low probability of interception and detection. Despite their point-to-point topology, additional security features may be required in privacy-critical applications. Encryption can be achieved at the physical layer by using quantized values of photons, which makes exploitation of such quantum communication links extremely difficult. One example of such technology is keyed communication in quantum noise, a novel quantum modulation protocol that offers ultra-secure communication with competitive performance characteristics. Its utilization relies on specific coherent measurements to decrypt the signal. The process of measurements is complicated by the inherent and irreducible quantum noise of coherent states. This problem is different from traditional laser communication with coherent detection; therefore continuous efforts are being made to improve the measurement techniques. Quantum-based encryption systems that use the phase of the signal as the information carrier impose aggressive requirements on the accuracy of the measurements when an unauthorized party attempts intercepting the data stream. Therefore, analysis of the secrecy of the data becomes extremely important. In this paper, we present the results of a study that had a goal of assessment of potential vulnerability of the running key. Basic results of the laboratory measurements are combined with simulation studies and statistical analysis that can be used for both conceptual improvement of the encryption approach and for quantitative comparison of secrecy of different quantum communication protocols.
Predicting malignant potential of subsolid nodules: can radiomics preempt longitudinal follow up CT?

To assess if radiomics can differentiate benign and malignant subsolid lung nodules (SSNs) on baseline or follow up chest CT examinations. If radiomics can differentiate between benign and malignant subsolid lung nodules, the clinical implications are shorter follow up CT imaging and early recognition of lung adenocarcinoma on imaging. The IRB approved retrospective study included 36 patients (mean age 69 ± 8 years; 5 males, 31 females) with 108 SSNs (31benign, 77 malignant) who underwent follow up chest CT for evaluation of indeterminate SSN. All SSNs were identified on both baseline and follow up chest CT. DICOM CT images were deidentified and exported into the open access 3D Slicer software (version 4.7) to obtain radiomic features. Logistic regression analyses and receiver operating characteristic (ROC) curves for various quantitative parameters were generated with SPSS statistical software. Only 2/92 radiomic features (cluster shade and surface volume ratio) enabled differentiation between malignant and benign SSN on baseline chest CT (P = 0.01 and 0.03) with moderate accuracy [AUC 0.624 (0.505–0.743)]. On follow-up CT, 52/92 radiomic features were significantly different between benign and malignant SSN (P: 0.04 - < 0.0001) with improved accuracy [AUC: 0.708 (0.605–0.811), P = 0.04 - < 0.0001]. Radiomics of benign SSN were stable over time, whereas 63/92 radiomic features of malignant SSNs changed significantly between the baseline and follow up chest CT (P: 0.04 - < 0.0001). Temporal changes in radiomic features of subsolid lung nodules favor malignant etiology over benign. The change in radiomics features of subsolid lung nodules can allow shorter follow up CT imaging and early recognition of lung adenocarcinoma on imaging. Radiomic features have limited application in differentiating benign and early malignant SSN on baseline chest CT.
Slow Beam Steering for Indoor Multi-User Visible Light Communications

Visible light communications (VLC) is an emerging technology that enables broadband data rates using the visible spectrum. VLC beam steering has been studied in the literature to track mobile users and to improve coverage. However, in some scenarios, it may be needed to track and serve multiple users using a single beam, which has not been rigorously studied in the existing works to our best knowledge. In this paper, considering slow beam steering where beam directions are assumed to be fixed within a transmission frame, we find the optimum steering angles to simultaneously serve multiple users within the frame duration. This is achieved by solving a non-convex optimization problem using grid based search and majorization-minimization (MM) procedure. Additionally, we consider multiple steerable beams case with larger number of users in the network, and propose an algorithm to cluster users and serve each cluster with a separate beam. The simulation results show that clustering users can provide higher rates compared to serving each user with a separate beam, and two user clusters maximizes the sum rate in a crowded room setting.
Bariatric surgery in patients with left ventricular assist devices: a safe and effective method of weight loss as a gateway to heart transplantation.

Abstract Background Severe cardiac disease often warrants intervention to improve cardiac function, such as mechanical support via a left ventricular assist device (LVAD). While this is an effective way of improving myocardial activity, it works synergistically with weight loss. Setting Academic hospital. Objective The aim of this study was to evaluate bariatric surgery as an alternative means of weight loss to improve cardiac status. Methods Six patients with LVADs underwent sleeve gastrectomies (SG) over a 5-year study period (2014–2018). Patient characteristics, cardiac history, operative outcomes, and follow-up was evaluated by univariate analyses. Results Median age at operation was 49.8 years (range, 24–58 yr) with average weight at surgery of 126.6 kg. Average body mass index at time of SG was 41.4 kg/m2. Median hospital length of stay was 8.5 days (range, 4–13 d), with postoperative length of stay of 5.5 days (3–7 d). Total follow-up was 29 months (range, 7–51 mo). Postoperative readmission occurred in 2 patients (33%) without significant adverse outcomes. Four patients (67%) were listed for transplant, 3 within 1 year of LSG. Three patients (50%) underwent orthotopic heart transplant. All patients experienced improved cardiac co-morbidities after SG. Conclusion We demonstrate that weight loss surgery as a bridge to transplantation for patients with implanted LVADs can be performed in young and middle-aged adults. Although it is limited by sample size, the reported results add to the existing literature highlighting the potential success of bariatric surgery in high-risk patient populations to achieve weight loss goals, impact cardiac co-morbidities, and improve overall quality of life.
Fiction on the Verge: Testing Taboos in The Republic of Wine

The epitome of non-Western magical realism in the service of political satire is offered by Nobel laureate Mo Yan, particularly in the masterwork of his mature style, The Republic of Wine. This essay examines the historical sources of the author’s Chinese approach to supernaturalism, tracing back thousands of years to the neolithic 东夷 (Dongyi) culture with its rich, almost Homeric tradition of oral storytelling which, in turn, informed the narrative methods of Pu Songling (a Qing dynasty master of ghost tales from Mo Yan’s native Shandong). The essay surveys this continuous literary tradition of ghost tales and relates it to Mo Yan’s archly critical satire. Its fantasy element counters the “dialectical materialism” behind Socialist Realism, the dominant mode of twentieth-century Chinese fiction. Mo Yan acknowledges his debt to Pu Songling as well as Buddhism. Although magical realism is generally attributed to Latin America, this essay shows how Mo Yan re-directs us to explore the non-Western, even universal or Jungian (“collective unconscious”) aspect of this metaphysical mode.
The influence of peer and coach relationships in after-school sports on perceptions of school climate:

Objective:Sport is an important source of physical, social and emotional health and well-being among children. Sports participation at school may provide young people with the opportunity to build ...
Near-Field Coherent Sensing of Vibration With Harmonic Analysis and Balance Signal Injection

The near-field coherent sensing (NCS) system can detect weak cyclic motion inside living bodies, such as human wrist pulses and the heartbeat of small animals. To couple significant energy to the motion source, a GHz RF carrier was employed, where the vibration amplitude was often much smaller than the wavelength. To optimize the signal quality, we presented a small-signal model with nonlinearity analysis by Jacobi–Anger expansion. The quiescent-point determination and signal composition were then discussed to guide the hardware and algorithm design. The model was validated by electromagnetic simulation in CST Studio and a simple robotic platform. A novel algorithm of adaptive control by signal injection was applied to boost both the signal magnitude and data converter utilization. The signal-to-quantization-noise ratio (SQNR) is improved by 35 dB and signal-to-noise ratio (SNR) by more than 10 dB. Sensing of vocal cord vibration was demonstrated as a potential application, where a harmonic radio frequency identification (RFID) system was chosen for its low noise floor to achieve high-fidelity recording of music scales and procedure words.
Readmissions and mortality in pediatric tracheostomy patients: Are we doing enough?

Abstract Objectives Pediatric patients who undergo tracheostomy tube placement are medically complex with a high risk of morbidity and mortality. They are often premature with multiple cardiopulmonary comorbidities. This study reviews the demographics and outcomes within this population to identify at-risk patient groups at our hospital. Methods A retrospective chart review of those with pediatric tracheostomy placement from 2015 to 2016 at our hospital was performed (n = 92). Demographic and post-discharge data were collected at 30, 60, and 90-days during the global period. Results Ventilator dependence was the most common reason for placement. 79.3% of patients had two or more major comorbidities. 44% had an emergency department (ED) visit and subsequent hospital admission within the first 90 days post-discharge, with 36% being trach/respiratory-related. The 90-day mortality was 19.6%; however, at the time of chart review, mortality was 35% with only 1 (1.1%) being from trach-related complications. Patients with longer admissions were more likely to die prior to discharge, p = .001. Lastly, patients who died were 3 times more likely to have > 25% no-shows to their outpatient appointments compared to those living throughout the study period. Conclusion Our population had a high incidence of ED visits, readmission rates, and mortality; however, trach-related causes remained low. Mortality risk increased with more no-show appointments and residing a further distance from our hospital. Furthermore, multiple co-morbidities, with longer hospital stays also increased risk of mortality. Identifying those with the highest risk for complications will enable us to target families for increased home-care education to decrease readmissions and mortality. Level of evidence 4.
The second purchase decision under selling price-sensitive stochastic demand and purchasing price uncertainty

It is quite common for a retailer to stock a specific quantity of a product more than once during a certain time period and then sell the product to the customers during the selling season. The retailer also has the option to make a second purchase, as long as there is a potential profit increase on account of the purchase. Due to the stochastic spot market purchasing price and the selling price dependent random demand, the retailer needs to determine whether a second purchase is necessary and if so what are the corresponding order time, quantity, and selling price in order to maximise the expected profit. In this paper, we develop a reality-adaptable solution algorithm to simplify the solution procedure. We also run simulations to analyse the inventory decisions, and to compute the profits when a second purchase is possible.
Cerebral underpinning of advanced mathematical activity

Abstract The human brain is especially unique within the animal kingdom in its understanding of abstract mathematical concepts. We are able to conceive irrational numbers, idealized geometrical shapes, abstract topological properties, and so on without ever perceiving them. How, then, do such concepts develop in the human mind? And what is the neural basis underlying the manipulation of high-level math concepts? While previous work mainly focused on arithmetic processing, the work reported in the present chapter focuses on more advanced math knowledge. This gives better account for the diversity of math domains such as analysis, algebra, topology, geometry, and so on that could call upon very different skills. One way to assess the brain mechanisms underlying advanced mathematical concepts’ ontogeny is to use functional MRI and study various mathematically skilled populations such as math professors or researchers, math students, or more generally math learners. The present chapter offers an overview of various neuroimaging studies assessing the cerebral underpinnings of advanced mathematical reflection and logical reasoning, as well as the effect of mathematical expertise on the brain. In professional mathematicians, including the exceptional cases of three blind mathematicians, these studies revealed that mathematical concepts are encoded in a very abstract manner. Notably, a set of brain areas including the bilateral intraparietal sulci and bilateral inferior-temporal regions appears to be systematically involved in mathematical activity. I then discuss the relation of this math-related network with language vs numerical-spatial processing in the brain, as well as its potential link to visual processes. I also discuss the potential overlap of the math-related network with the neural correlates of deductive reasoning, a process that is at the heart of the modern mathematical practice of proofs. Finally, this chapter briefly reviews the main brain markers that have been found to accompany mathematical expertise or giftedness.
Planning for the Unknown: Local Government Strategies from the Fiscal Year 2021 Budget Season in Response to the COVID-19 Pandemic

This article outlines how counties and municipalities in North Carolina prepared their fiscal year 2020–21 budgets amid the uncertainties of the COVID-19 pandemic. In response to an April 2020 surv...
Surgical Management of Upper Tract Urothelial Carcinoma– Open, Laparoscopic, and Robotic Approaches to Nephroureterectomy and Outcomes

It is estimated that upper tract urothelial carcinoma (UTUC) is a rare disease making up only 5–6 % of all urothelial cell malignancies, and occur in only 1–4 people per 100,000 with a peak incidence in the 6th and 7th decades occurring in men more frequently than women [1]. Perhaps due to the rarity of incidence limiting research knowledge and the relatively aggressive nature at times of UTUC, surgical management of UTUC tends to be more aggressive than that of the lower tract. In order to adequately stage the disease, there is a heavy reliance on radiographic and visual imaging via ureteroscopy. The reason for this reliance on imaging and direct visualization is primarily due to the problem of obtaining tissue biopsies to accurately gauge depth of invasion. There are severe size limitations on the biopsy forceps, as it must fit through an ureteroscope. As a result, a reliance has been on grading of the cellular atypia rather than the clinical T stage of the disease. Indeed, studies have shown direct correlation with tumor grade and degree of invasion on final pathologic analysis although under-grading occurs up to 25 % of the time [2]. Anatomically, there are relatively thinner layers of tissue between the surface of the urothelium to the adventitia of the ureter for the development of locally advanced disease in the kidney and ureter, as compared to the urothelium in the bladder. This causes a higher risk of each lesion to progress. Furthermore, as opposed to cases of bladder cancer with superficial high-grade disease, where one has the options to treat with intravesical washings of chemotherapies and immunotherapies via a catheter, in UTUC it is necessary to use sedation or anesthesia to cystoscopically place a ureteral catheter or to percutaneously place a nephrostomy tube. Despite the invasive nature of applying the treatment, and limitations due to natural peristalsis, utilization of various methods of renal pelvic and ureteral irrigation with BCG is an option for select patients with CIS of the upper tracts [3, 4]. As organ-sparing options with intraluminal chemotherapies are limited, and the relatively thinner barriers for tumor progression compared to lower tract urothelial carcinoma (LTUC); the gold standard for treatment of UTUC continues to be radical nephroureterectomy (RNU). In this chapter we will discuss the surgical management of UTUC as well as innovations in the surgical approach and current controversies.
The determination of transfer ribonucleic acid by aminoacylation: I. Leucine and phenylalanine transfer ribonucleic acid from E. coli B☆

A study was made of the aminoacylation of purified and partially purified transfer ribonucleic acids by 14C-labeled amino acids using a crude synthetase enzyme preparation, and the optimum conditions have been established for the quantitative determination of purified leucine and phenylalanine accepting transfer ribonucleic acids from E. coli B. An analytical procedure was developed for the determination of picomolar quantities of these two nucleic acids, based on a filter paper disc technique and scintillation spectrometry. Relevant solution parameters have been investigated, including: pH, type of buffer, incubation time, concentrations of transfer ribonucleic acid, amino acid, adenosine triphosphate, and aminoacyl-tRNA synthetase, as well as concentration of divalent metal ion cofactors. The optimum pH for the aminoacylation reaction is 8–8.5; cacodylate and glycinate buffers were preferred, respectively, for the formation of the leucyl- and phenylalanyl-tRNA's. Magnesium and manganese appeared to be equally effective as cofactors, while sodium chloride and phosphate used in chromatographic separation of the tRNA's had inhibiting effects. The hydrolytic half-lives of the two tRNA esters at the pH of optimum formation were 23–24 min for the Phe-tRNA and 7 min for Leu-tRNA.
Ecological, organismal, and cellular explorations of three medically significant species of ticks in Iowa

vi Chapter 1: Introduction and Background 1 1.1 General Introduction 1 1.2 Medically Significant Ticks of Iowa 2 1.3 Iowa Lyme Disease Surveillance Program 9 1.4 Arthropod Immune Responses 11 1.5 Pathogenic and Commensal TickAssociated Microorganisms 18 References 26 Chapter 2: Distribution, Range Expansion, and Infection with Borrelia burgdorferi of Ixodes scapularis Ticks in Iowa 33 Abstract 33 2.
Analysis of cleavage fracture potential of martensitic stainless steel fusion structures: Part II. Fracture analysis procedures for flawed fusion structures

Abstract The potential for brittle cleavage fracture is a major concern for martensitic stainless steels which are candidates for fusion reactor structural materials. This study attempts to identify for flawed fusion structures the pertinent fracture resistance or failure parameters and the relationships between these parameters and the basic materials properties which govern cleavage fracture. Several procedures for relating test data to failure prediction, including Charpy-V-notch transition temperature referencing and two-parameter interpolation procedures, are considered; and results are discussed with respect to possible research paths for martensitic stainless steel alloy development.
Real-time scheduling of electric vehicles for ancillary services

This work is part of a project that aims to demonstrate the concept of Vehicle-to-Grid (V2G) with an operational fleet. A fleet of electric vehicles is operated with the objective of providing regulation services to the grid. The focus of this paper is on the real-time operation of the fleet. Specifically, given an optimal trajectory for the vehicle state of charge, schemes for distributing the regulation power commands among the vehicles are tested. A scheme based on a convex optimization problem is proposed. Several numerical illustrations and simulations show the effectiveness of the scheme respect to common scheduling heuristics in terms of accuracy.
The implications of the Tadoma method of speechreading for spoken language processing

Strong support of the capacity of touch as a communicative sense is provided by the Tadoma method of communication. Through this method, individuals who are deaf-blind have been able to acquire a full range of spoken language abilities. In the Tadoma method, direct contact is made between the hand of the deaf-blind receiver and the face of a talker to monitor the various articulatory actions that occur during speech. Studies conducted with a group of experienced deaf-blind practitioners of Tadoma have documented their abilities for speech reception, speech production, and linguistic competence. The results of this research indicate that individuals who suffered deaf-blindness in early childhood (e.g., around 18 months of age) can understand speech produced at slow-to-normal rates with reasonable accuracy, can produce speech that is reasonably intelligible to many listeners, and have an extensive command of English that compares favorably in many areas to that of hearing individuals. The performance of these deaf-blind individuals implies the adequacy of the tactual sense to support the development of speech and language and thereby provides a strong impetus for continued research on the development of sensory substitution devices for spoken language processing. Current efforts on the development and evaluation of artificial tactile devices for speech communication are discussed.
Manganese-Induced Parkinsonism Is Not Idiopathic Parkinson’s Disease: Environmental and Genetic Evidence

Movement abnormalities caused by chronic manganese (Mn) intoxication clinically resemble but are not identical to those in idiopathic Parkinson’s disease. In fact, the most successful parkinsonian drug treatment, the dopamine precursor levodopa, is ineffective in alleviating Mn-induced motor symptoms, implying that parkinsonism in Mn-exposed individuals may not be linked to midbrain dopaminergic neuron cell loss. Over the last decade, supporting evidence from human and nonhuman primates has emerged that Mn-induced parkinsonism partially results from damage to basal ganglia nuclei of the striatal “direct pathway” (ie, the caudate/putamen, internal globus pallidus, and substantia nigra pars reticulata) and a marked inhibition of striatal dopamine release in the absence of nigrostriatal dopamine terminal degeneration. Recent neuroimaging studies have revealed similar findings in a particular group of young drug users intravenously injecting the Mn-containing psychostimulant ephedron and in individuals with inherited mutations of the Mn transporter gene SLC30A10. This review will provide a detailed discussion about the aforementioned studies, followed by a comparison with their rodent analogs and idiopathic parkinsonism. Together, these findings in combination with a limited knowledge about the underlying neuropathology of Mn-induced parkinsonism strongly support the need for a more complete understanding of the neurotoxic effects of Mn on basal ganglia function to uncover the appropriate cellular and molecular therapeutic targets for this disorder.
Fibrous dysplasia of the proximal femur: surgical management options and outcomes.

Purpose The management of proximal femoral deformity in fibrous dysplasia (FD) is a challenge to the orthopaedic surgeon. The purpose of this study was to analyze the various presentations of FD of proximal femur and the results of the various treatment modalities for the same.
Effects of prenatal exposure to morphine sulfate on reproductive function of female rats

Abstract The purpose of this study was to investigate the effect of prenatal exposure to morphine sulfate on the development of reproductive function in female rats. Female rats exposed to morphine sulfate in utero (5–10 mg/kg on days 5–12 of gestation) exhibited varying dates of vaginal opening and a partial inhibition in adult feminine sexual behavior when compared to controls. However, the estrogen binding capacity of hypothalamic cytosols from morphine- and saline-treated females was identical. While we cannot rule out the possibility that the observed changes in reproductive function were an indirect result of morphine-induced alterations in maternal physiology or behavior, these results suggest that the development of feminine sexual behavior can be influenced during the early prenatal period and that morphine sulfate can affect the process of feminization.
Variational principle for perfect and imperfect fluids in general relativity

The Einstein equations and the relativistic Navier-Stokes equations for a simple fluid characterized by an arbitrary flux tensor are obtained by an action principle to which the equation for the entropy production is added as a constraint. The procedure is a generalization of the classical Herivel variational principle to relativistic and dissipative systems. The inclusion of dissipative processes requires a reformulation of the action integral to refer to a proper-time slice (tau/sub 1/,tau/sub 2/) in the limit tau/sub 2/ ..-->.. tau/sub 1/, otherwise their nonconservative nature gives rise to non-Markoffian effects. Such a procedure is called a differential variational principle (DVP). The principle of least dissipation of energy can be incorporated into the DVP so that a linear form for the flux tensor can be produced as well as the above-mentioned equations.
Current issues in public urban education

Abstract The 100 largest school districts in the United States educate 22.9 percent of our nation's K‐12 students, yet they represent a mere 0.6 percent of the school districts serving these children. Often faced with older buildings and more children who are “at risk” for various reasons, urban districts face tremendous challenges in educating these youngsters. A number of educational reforms taking hold across the country offer promise for improvement. Implementation of site‐based management, which allows officials and teachers at the school level to focus on the specific needs of the children for whom they are responsible, offers promise for improving schools across the nation, particularly in urban areas. Other reforms are not as well tested but also show promise. Today there are a number of successful schools in urban areas, giving hope that, in the future, more children in our largest cities will attend schools that offer them greater opportunities.
Labeling amalgamations of Cartesian products of complete graphs with a condition at distance two

Abstract The spectrum allocation problem in wireless communications can be modeled through vertex labelings of a graph, wherein each vertex represents a transmitter and edges connect vertices whose corresponding transmitters are operating in close proximity. One well-known model is the L ( 2 , 1 ) -labeling of a graph G in which a function f maps the vertices of G to the nonnegative integers such that if vertices x and y are adjacent, then | f ( x ) − f ( y ) | ≥ 2 , and if x and y are at distance two, then | f ( x ) − f ( y ) | ≥ 1 . The λ -number of G is the minimum span over all L ( 2 , 1 ) -labelings of G . Informally, an amalgamation of two graphs G 1 and G 2 along a fixed graph G 0 is the simple graph obtained by identifying the vertices of two induced subgraphs isomorphic to G 0 , one in G 1 and the other in G 2 . In this work, we supply a tight upper bound for the λ -number of amalgamations of several Cartesian products of complete graphs along a complete graph and find the exact λ -numbers for certain infinite subclasses of amalgamations of this form. A surprising relationship between the former upper bound and the minimum makespan scheduling problem is highlighted.
Melanotropic peptides in the mammalian brain : the melanin-concentrating hormone

Abstract Melanin-concentrating hormone (MCH) has been identified in neurons of the mammalian brain. This review summarizes some current information regarding the cell biology of this neuropeptide and the topography of MCH-immunoreactive (-IR) neurons in several species including mouse, rat, hamster, guinea pig, rabbit, dog and monkey; an atlas of MCH-IR neurons in the hypothalamus and subthalamus of the brain of guinea pig is presented. Based upon the location of this MCH cell group, it is hypothesized that they may be functionally involved in circuits of extrapyramidal motor systems from striatal centers to the thalamus and cerebral cortex and to the midbrain and spinal cord.
The angiographic spectrum of the thoracic outlet syndrome: With emphasis on mural thrombosis and emboli and congenital vascular anomalies

A spectrum of young patients presenting with upper extremity pulse deficits is presented. The angiographic findings in compression syndromes, congenital, atheromatous and traumatic lesions are shown. A discussion of mural thrombosis and emboli emphasizing early diagnosis follows.
Sell or Hold: A simple two-stage stochastic combinatorial optimization problem

Abstract The sell or hold problem (SHP) is to sell k out of n indivisible assets over two stages, with known first-stage prices and random second-stage prices, to maximize the total expected revenue. We show that SHP is NP-hard when the second-stage prices are realized as a finite set of scenarios. We show that SHP is polynomially solvable when the number of scenarios in the second stage is constant. A max { 1 / 2 , k / n } -approximation algorithm is presented for the scenario-based SHP.
Stochastic modeling of preform heterogeneity to address dry spots formation in the VARTM Process

Abstract Dry spot formation during the filling process was investigated for a system consisting of a heterogeneous porous medium coupled with a homogeneous porous layer. This system is representative of a composite manufacturing process in which the resin is introduced through an injection gate into a mold containing stacks of woven fabrics and a vacuum is drawn at the downstream end to impregnate the fibers. Dry spots are the regions that are not impregnated by the resin when the resin reaches the vent. The heterogeneity of the porous medium was quantified by modeling it with by-pass paths. They represent the gaps at the intersections of fiber tows in woven fabrics and have a larger permeability than the bulk porous medium permeability. When these fabrics are stacked to form a preform before injecting the resin, it is probable that some of these gaps across the thickness for all the layers would be inline creating the by-pass path for the resin. Hence, the need for stochastic modeling and random distribution of these by-pass paths. A log–normal distribution, Kbp∼LN(μ,σK) was chosen to describe their formation. A five-parameter space was defined to describe the stochastic system. Numerical simulations of resin flow in this space for discrete combinations of the parameters were performed and the dry spot content (cDR) was obtained. The average dry spot content ( c ¯ DR ) and its standard deviation (σDR) were calculated by conducting sufficient number of simulations with random placement of by-pass paths for each set of parameters. It was found that ( c ¯ DR ) and (σDR) depends on (σK), but the influence of (σK) on ( c ¯ DR ) and (σDR) can be altered by adjusting other parameters.
A Tight Inverse Semigroup Which Is Not Bisimple

We give an example of a tight inverse semigroup which is not bisimple and not congruence-free.
Development of a genetic system for a model manganese-oxidizing proteobacterium, Leptothrix discophora SS1.

Understanding the molecular underpinnings of manganese oxidation in Leptothrix discophora SS1 has been hampered by the lack of a genetic system. In this report, we describe the development of a genetic system for L. discophora SS1. The antibiotic sensitivity was characterized, and a procedure for transformation with exogenous DNA via conjugation was developed and optimized, resulting in a maximum transfer frequency of 5.2×10−1 and a typical transfer frequency of the order of 1×10−3 transconjugants per donor. Genetic manipulation of L. discophora SS1 was demonstrated by disrupting pyrF via chromosomal integration with a plasmid containing a R6Kγ origin of replication through homologous recombination. This resulted in resistance to 5-fluoroorotidine, which was abolished by complementation with an ectopically expressed copy of pyrF cloned into pBBR1MCS. This system is expected to be amenable to a systematic genetic analysis of L. discophora SS1, including those genes responsible for manganese oxidation.
A Lagrangian approach for quantum-mechanical electrostatic analysis of deformable silicon nanostructures

Semiconductor mechanical components of nanoelectromechanical systems (NEMS) typically undergo deformations when subjected to electrostatic forces. Computational analysis of electrostatic NEMS requires an electrostatic analysis to compute the electrostatic forces acting on the nanomechanical structures and a mechanical analysis to compute the deformation of the nanomechanical structures. Typically, the mechanical analysis is performed by a Lagrangian approach using the undeformed position of the structures. However, the electrostatic analysis is performed by using the deformed position of the nanostructures. The electrostatic analysis on the deformed position of the nanostructures requires updating the geometry of the structures during each iteration. In this paper, based on a recently proposed hybrid BIE/Poisson/Schrodinger approach, we propose Lagrangian formulations for the BIE/Poisson/Schrodinger equations and solve the coupled Lagrangian BIE/Poisson/Schrodinger's equations self-consistently using the undeformed position of the semiconductors to compute the charge distributions on the deformed semiconductors. The proposed approach eliminates the requirement of updating the geometry and, consequently, significantly simplifies the procedure of coupled electromechanical analysis of NEMS.
Preparation of Coordination Compounds of Cp*2Yb with Heterocyclic Nitrogen Bases: Examples of Antiferromagnetic Exchange Coupling across Bridging Ligands

Several adducts are isolated between heterocyclic nitrogen bases and Cp*2Yb. The adducts fall into several general classes. The membership within the class is related to the reduction potential of the given heterocyclic base relative to that of Cp*2Yb. Analytically pure 1:1 adducts of the type Cp*2Yb(L) are formed with pyrazine, quinoxaline, 1,5- and 1,8-naphthyridine, and 4,4‘-bipyridine as toluene-insoluble solids. The 1:1 adducts with phthalazine and azobenzene and the 1:2 adduct with pyridazine are soluble in toluene, from which they may be isolated by crystallization. All of the adducts in this class are paramagnetic, and their effective magnetic moments are consistent with the formulation Cp*2YbIII(L•-) (L•- = radical anion), in which spins on the individual units are uncoupled to 5 K. Adducts between Cp*2Yb and phenazine, 2,2‘-azopyridine, 2,2‘-bipyrimidine, 2,2‘-azobenzene, and 2,3-bis(2-pyridino)quinoxaline are of 2:1 stoichiometry: (Cp*2Yb)2(μ-L). The crystal structure of (Cp*2Yb)2(μ-bipyrimidi...
Effects of different organic carbon sources on a freshwater plankton community

We examined effects of terrestrial and aquatic detritus on optical, chemical, and biological properties of a planktonic food web in mesotrophic Calder Lake, New York. The 5400-L mesocosms received ...
Prokaryotic transcriptional enhancers and enhancer-binding proteins.

Abstract A number of prokaryotic enhancer-binding proteins activate transcription by specialized forms of RNA polymerase. The enhancer-binding proteins catalyse isomerization of the initial complex formed between RNA polymerase and a promoter from the closed to the open state. To do so, one class of enhancer-binding proteins contacts its cognate polymerase by DNA loop formation but the other, which is represented by a single member, does not. Despite this difference, both classes of enhancer-binding proteinsmust hydrolyse ATP to catalyse open complex formation.
The Coronal Metallicity of the Intermediate Activity Dwarf ξ Bootis A

Extreme Ultraviolet Explorer (EUVE) spectra from a 270 ks observation of the intermediate activity star ξ Boo A (G8 V) have been analyzed in order to determine the metallicity of its coronal plasma. This analysis was based on a new method that used both the EUVE spectroscopic and photometric (Deep Survey) data, together with theoretical model spectra. By comparison of observed and synthetic spectra computed using the CHIANTI database, we estimated that about 20% of the observed line flux is not accounted for in the theoretical model. Allowing for the "missing lines" in our analysis, we obtain a coronal metallicity for ξ Boo A of [M/H] = 0.1 relative to the solar photosphere. This is slightly higher than the photospheric metallicity of [M/H] = -0.15 ± 0.05 and lends support to the results of our earlier analysis of the same spectral data that indicated that coronal abundances of elements with low first ionization potentials (FIPs) are systematically higher than those of elements with high FIPs. These results, coupled with other evidence, imply that stars of intermediate activity level—stars more active than the Sun but significantly less active than the most active single and binary stars—do not suffer from any depletion of metals in their coronae as some coronal metallicities estimated for more active stars have appeared to suggest. The observation of a solar-like FIP effect on ξ Boo A adds support to the notion that stars of intermediate activity level have coronae characterized by a high surface coverage of bright solar-like active regions.
Human endothelial colony forming cells undergo vasculogenesis within biphasic calcium phosphate bone tissue engineering constructs

Abstract An important consideration in bone regeneration is the need for expedited neovascularization within the defect site. Formation of a vascular network is critical for cell viability and normal function leading to tissue regeneration, but spontaneous angiogenesis is too slow to yield sufficient vessel formation. In this pilot study, human umbilical cord blood (hUCB)-derived endothelial colony forming cells (ECFCs) were evaluated for in vivo vasculogenesis in the macropores of biphasic calcium phosphate (BCP)/bone morphogenetic protein-2 (BMP-2) bone tissue engineering constructs. Constructs were implanted on the abdominal wall of NOD/SCID mice for 4 weeks. This study demonstrated in vivo vasculogenesis by human ECFCs within the macropore space of BCP/BMP-2 constructs. The human ECFC-derived vessels anastomosed with the host vasculature and perfused vessels were visible in the very center of the 5 mm diameter, 2.5 mm tall scaffolds. Additionally, the vessels were evenly distributed throughout the construct. This study suggests that scaffolds containing ECFCs have significant potential for expedited neovascularization in bony defects.
Influence of high-energy electron irradiation on the conduction behavior of doped polyaniline films in the high current density regime

Abstract The influence of high-energy electron irradiation on the conduction behavior at high current density of polyaniline (PANI) films doped with HCl and camphor sulfonic acid (HCSA), respectively, is reported. It is found that there exists an ohmic region under certain current density for both non-irradiated and irradiated samples. No significant change of the conductivity and maximum current density are observed if the sample is irradiated at room temperature and low dosage. The conductivity and maximum current density decrease with dosage if the samples are irradiated at high temperature. However, after redoping with 1 M HCl, the conductivity of these films can be recovered, while the maximum current density remains at a lower level. The DSC thermograms show that the crosslinking density of PANI–HCl film increases due to the high-energy electron irradiation.
Aggregate stabilization in kaolinitic soils by low rates of anionic polyacrylamide

The stability of aggregates can be improved by amending the soil with charged synthetic polymers. We have evaluated the effects of addition of low rates of anionic polyacrylamide (PAM) on the stability of aggregates from three predominately kaolinitic soils, and investigated whether the applied PAM penetrated into the aggregates or was adsorbed onto exterior surfaces only. Aggregates (6.3-9.5 mm) from the Ap horizons of Cecil sandy loam and a Cecil loamy sand (Typic Kanhapludult) and from the Bt horizon of a Davidson clay (Rhodic Kandiudult) were treated with a high molecular weight (2 x 10 7 Da), negatively charged (20% hydrolysis) PAM at rates of 0, 10 or 20 kg/ha. The treated aggregates were dried and exposed to 20 mm of high kinetic energy (23.0 kJ/m 3 ) simulated rain. Some of the PAM-treated Cecil loamy sand aggregates (5 or 10 kg/ha) were broken in half to expose untreated aggregate interiors to the rain. Percentage stable aggregates (weight/weight) in the PAM treatments ranged from 52 to 97%, vs. 20-32% in the control. PAM addition significantly increased the percentage of >4 mm sized aggregates compared with the untreated aggregates. PAM was more effective at stabilization in the light to medium textured Cecil soils than in the clayey Davidson. When internal surfaces of PAM treated aggregates were exposed, the percentage of stable aggregates exceeded the amount expected if the polymer was only adsorbed on to external surfaces. This suggested that some PAM had penetrated to some degree into aggregate interiors, thereby stabilizing both external and internal aggregates surfaces. Based on these results it is envisaged that use of PAM could be a viable alternative to the commonly used soil and water conservation practices (e.g. mulching, dyking, contour tillage).
Cervical Cancer Screening Outreach Among Low Income, Immigrant, and Minority Communities in Los Angeles County

Abstract High cervical cancer mortality rates continue to be a significant problem in some sectors of the population. This study analyzes the success of the Los Angeles County Office of Women's Health free cervical cancer screening program in overcoming barriers that inhibit at-risk women (e.g., low income, immigrant, Hispanic, and Asian Pacific Islander women) from getting screened. The researchers assess the effectiveness of their two major outreach strategies—community outreach and mass media appeals—in mobilizing different groups of women. The study also identifies barriers to access that contribute to no show behavior on the part of women who had scheduled screening appointments.
Quantitative Effects of Global Tempo on Expressive Timing in Music Performance: Some Perceptual Evidence

This study examines whether global tempo and expressive timing microstructure are independent in the aesthetic judgment of music performance. Measurements of tone interonset intervals in pianists9 performances of pieces by Schumann ("Traumerei") and Debussy ("La fille aux cheveux de lin") at three different tempi show a tendency toward reduced relative variation in expressive timing at both faster and slower tempi, relative to the pianist9s original tempo. However, this could reflect merely the pianists9 discomfort when playing at an unfamiliar tempo. Therefore, a perceptual approach was taken here. Experimental stimuli were created artificially by independently manipulating global tempo (three levels) and "relative modulation depth" of expressive timing (RMD, five levels) in MIDI-recorded complete performances of the Schumann and Debussy pieces. Skilled pianists rated the quality of the resulting two sets of 15 performances on a 10-point scale. The question was whether the same RMD would receive the highest rating at all three tempi, or whether an interaction would emerge, such that different RMDs are preferred at different tempi. A small but significant interaction was obtained for both pieces, indicating that the listeners preferred a reduced RMD when the tempo was increased, but the same or a larger RMD when the tempo was decreased. Thus, they associated an increase in tempo with a decrease in (relative) expressive timing variation, which, in general agreement with the performance data, suggests that the two temporal dimensions are not independent.
Structure of an exploding laser-produced plasma.

We describe the first-ever volumetric, time-resolved measurements performed with a moving probe within an expanding dense plasma, embedded in a background magnetized plasma. High-resolution probe measurements of the magnetic field and floating potential in multiple 2D cut planes combined with a 1 Hz laser system reveal complex three-dimensional current systems within the expanding plasma. Static (${\ensuremath{\omega}}_{\mathrm{real}}=0$) flutelike density striations are observed at the leading edge of the plasma, which are correlated to variations in the current layer at the edge of the expanding plasma.