cssi/SciSciGPT-SciSciNet huggingface dataset:
Use of Allografts in Orthopaedic Surgery: Safety, Procurement, Storage, and Outcomes:

The use of allografts has become a vital option for orthopaedic surgeons in the treatment of a variety of musculoskeletal lesions, ranging from osteochondral defects in the glenohumeral joint to meniscal deficiency in the young athlete. Nevertheless, barriers to treating a patient with an allograft-based procedure may arise from concerns over disease transmission, the navigation of tissue banks that supply allografts, the process of obtaining insurance approval, or optimal storage methods. This review serves to support orthopaedic surgeons in the incorporation of allografts into their practice by quelling these potential concerns. Fresh osteochondral allografts, fresh-frozen meniscal allografts, soft tissue allografts, and off-the-shelf cartilage products are the focus of this review amid broad overviews of allograft safety and tissue bank practices in the United States.
World Programs for Model-Based Learning and Planning in Compositional State and Action Spaces.

Some of the most important tasks take place in environments which lack cheap and perfect simulators, thus hampering the application of model-free reinforcement learning (RL). While model-based RL aims to learn a dynamics model, in a more general case the learner does not know a priori what the action space is. Here we propose a formalism where the learner induces a world program by learning a dynamics model and the actions in graph-based compositional environments by observing state-state transition examples. Then, the learner can perform RL with the world program as the simulator for complex planning tasks. We highlight a recent application, and propose a challenge for the community to assess world program-based planning.
EEG Signal Compression using Fuzzy Transform

A compression algorithm based on fuzzy transform (FT) is presented in this paper for electroencephalogram (EEG) signals. A fuzzy-based mathematical kernel is exploited which transforms the data into a new domain where their cardinality can be reduced to allow the development of efficient data compression algorithms. The presented method, which is assessed using different EEG signals, achieves good compression ratios (CR) with minimum distortion.
Systematic study of the influence of iR compensation on water electrolysis

Abstract Water electrolysis has been one of the most studied topics in materials research in the past decade because of the global effort in exploring clean and renewable energy sources. Much effort has been devoted to developing highly active electrocatalysts for the two half reactions of water electrolysis, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Some reported electrocatalysts are even superior to the benchmark platinum and iridium dioxide catalysts, and thus are claimed to be promising for large-scale commercial use. However, most electrochemical data in the literature are reported after iR compensation, where R is the overall resistance, including contact resistance, charge-transfer resistance, and intrinsic resistance. Unfortunately, these types of resistance cannot be avoided in real electrolyzers, which means that R still results in energy consumption if the electrocatalysts are used for industrial water electrolysis. Thus, the data with iR compensation are always misleading, and setting criteria for iR compensation in analyses of water electrolysis is urgently needed to instruct the scientific community. In this work, we test the catalytic performance of several reported HER and OER catalysts with and without iR compensation and discuss the contribution from iR compensation under small and large current densities. We also present a comparative study between two iR compensation methods (automatic and manual iR compensation). Finally, we propose some strategies to reduce the R to achieve better performance without iR compensation, which is necessary for industrial applications.
Factors That Influence Health-Promoting Behaviors in Cancer Caregivers.

Objectives To describe cancer caregivers' participation in health-promoting behaviors and to identify factors influencing participation. Sample & setting 129 informal cancer caregivers at the National Institutes of Health Clinical Center. Methods & variables Cross-sectional survey methodology using Health-Promoting Lifestyle Profile-II (HPLP-II), PROMIS® Global Physical Health, NIH Toolbox Stress and Self-Efficacy, Caregiver Reaction Assessment, and Family Care Inventory Mutuality subscale. Results Caregivers reported the highest HPLP-II subscale scores for spirituality and interpersonal relationships and the lowest for physical activity. Caregivers who were older, with lower body mass indices, in better physical health, and with higher self-efficacy and mutuality participated in more health-promoting behaviors. Sixty percent of the caregivers reported that they exercised less since becoming a caregiver, and 47% reported that their diet was worse. Implications for nursing Future research is needed to examine novel interventions to increase health-promoting activities in cancer caregivers, and these interventions might be strengthened by including components that focus on increasing self-efficacy and/or improving the strength of the relationship between the caregiver and care recipient.
Air, Ether, Atmosphere: Space in Rilke’s Duineser Elegien

This essay argues that the Duineser Elegien articulate Rilke’s conception of air as a material expression of space. The Elegies present spaces pervaded by aerial substances such as breath, wind and...
Fetal heart rate during maternal sleep

Despite prolonged and cumulative exposure during gestation, little is known about the fetal response to maternal sleep. Eighty-four pregnant women with obesity (based on pre-pregnancy BMI) participated in laboratory-based polysomnography (PSG) with continuous fetal electrocardiogram monitoring at 36 weeks gestation. Multilevel modeling revealed both correspondence and lack of it in maternal and fetal heart rate patterns. Fetal heart rate (fHR) and variability (fHRV), and maternal heart rate (mHR) and variability (mHRV), all declined during the night, with steeper rates of decline prior to 01:00. fHR declined upon maternal sleep onset but was not otherwise associated with maternal sleep stage; fHRV differed during maternal REM and NREM. There was frequent maternal waking after sleep onset (WASO) and fHRV and mHRV were elevated during these episodes. Cross-correlation analyses revealed little temporal coupling between maternal and fetal heart rate, except during WASO, suggesting that any observed associations in maternal and fetal heart rates during sleep are the result of other physiological processes. Implications of the maternal sleep context for the developing fetus are discussed, including the potential consequences of the typical sleep fragmentation that accompanies pregnancy.
EPIC: A Proposed Model for Approaching Metadata Improvement

This paper outlines iterative steps involved in metadata improvement within a digital library: Evaluate, Prioritize, Identify, and Correct (EPIC). The process involves evaluating metadata values system-wide to identify errors; prioritizing errors according to local criteria; identifying records containing a particular error; and correcting individual records to eliminate the error. Based on the experiences at the University of North Texas (UNT) Libraries, we propose that these cyclical steps can serve as a model for organizations that are planning and conducting metadata quality assessment.
Olfactory Encoding Within the Insect Antennal Lobe: The Emergence and Role of Higher Order Temporal Correlations in the Dynamics of Antennal Lobe Spiking Activity

Abstract In this review, we focus on the antennal lobe (AL) of three insect species – the fruit fly, sphinx moth, and locust. We first review the experimentally elucidated anatomy and physiology of the early olfactory system of each species; empirical studies of AL activity, however, often focus on assessing firing rates (averaged over time scales of about 100 ms), and hence the AL odor code is often analyzed in terms of a temporally evolving vector of firing rates. However, such a perspective necessarily misses the possibility of higher order temporal correlations in spiking activity within a single cell and across multiple cells over shorter time scales (of about 10 ms). Hence, we then review our prior theoretical work, where we constructed biophysically detailed, species-specific AL models within the fly, moth, and locust, finding that in each case higher order temporal correlations in spiking naturally emerge from model dynamics (i.e., without a prioriincorporation of elements designed to produce correlated activity). We therefore use our theoretical work to argue the perspective that temporal correlations in spiking over short time scales, which have received little experimental attention to-date, may provide valuable coding dimensions (complementing the coding dimensions provided by the vector of firing rates) that nature has exploited in the encoding of odors within the AL. We further argue that, if the AL does indeed utilize temporally correlated activity to represent odor information, such an odor code could be naturally and easily deciphered within the Mushroom Body.
The remarkable properties of carbon nanotubes as nanoclusters

A brief overview will be given of the unique structure and properties of carbon nanotubes (diameters ~ 1.3 run), The remarkable electronic properties of carbon nanotubes relate to predictions and observations that these structures can be either semiconducting or metallic, depending on their geometry. Resonant Raman scattering along with scanning tunneling microscopy/spectroscopy have provided a powerful characterization tool for probing the one-dimensional (1D) density of electronic states of the carbon nanotubes, while also providing important information on the structure and lattice vibrational modes in these unique 1D nanostructures.
Closed-Form Analytical Results for Maximum Entropy Reinforcement Learning.

We introduce a mapping between Maximum Entropy Reinforcement Learning (MaxEnt RL) and Markovian processes conditioned on rare events. In the long time limit, this mapping allows us to derive analytical expressions for the optimal policy, dynamics and initial state distributions for the general case of stochastic dynamics in MaxEnt RL. We find that soft-$\mathcal{Q}$ functions in MaxEnt RL can be obtained from the Perron-Frobenius eigenvalue and the corresponding left eigenvector of a regular, non-negative matrix derived from the underlying Markov Decision Process (MDP). The results derived lead to novel algorithms for model-based and model-free MaxEnt RL, which we validate by numerical simulations. The mapping established in this work opens further avenues for the application of novel analytical and computational approaches to problems in MaxEnt RL. We make our code available at: this https URL
Implementation of collaborative care for depressive disorder treatment among accountable care organizations

Collaborative care - primary care models combining care management, consulting behavioral health clinicians, and registries to target mental health treatment - is a cost-effective depression treatment model, but little is known about uptake of collaborative care in a national setting. Alternative payment models such as accountable care organizations (ACOs), in which ACOs are responsible for quality and cost for defined patient populations, may encourage collaborative care use.Determine prevalence of collaborative care implementation among ACOs and whether ACO structure or contract characteristics are associated with implementation.Cross-sectional analysis of 2017-2018 National Survey of ACOs (NSACO). Overall, 55% of ACOs returned a survey (69% of Medicare, 36% of non-Medicare ACOs); 48% completed at least half of core survey questions. We used logistic regression to examine the association between implementation of core collaborative care components - care management, a consulting mental health clinician, and a patient registry to track mental health symptoms - and ACO characteristics.Four hundred five National Survey of ACOs respondents answering questions on collaborative care implementation.Only 17% of ACOs reported implementing all collaborative care components. Most reported using care managers (71%) and consulting mental health clinicians (58%), =just 26% reported using patient registries. After adjusting for multiple ACO characteristics, ACOs responsible for mental health care quality measures were 15 percentage points (95% CI 5-23) more likely to implement collaborative care.Most ACOs are not utilizing behavioral health collaborative care. Including mental health care quality measures in payment contracts may facilitate implementation of this cost-effective model. Improving provider capacity to track and target depression treatment with patient registries is warranted as payment contracts focus on treatment outcomes.
Finite-temperature vibrational full configuration interaction

Thermodynamic functions of an ideal molecular gas due to its anharmonic vibrations are evaluated in a wide range of temperature (T) by the vibrational full-configuration-interaction (FCI) method us...
Single-cell RNA-seq reveals a critical role of novel pro-inflammatory EndMT in mediating adverse remodeling in coronary artery-on-a-chip

A three-dimensional microengineered human coronary artery-on-a-chip was developed for investigation of the mechanism by which low and oscillatory shear stress (OSS) induces pro-atherogenic changes. Single-cell RNA sequencing revealed that OSS induced distinct changes in endothelial cells (ECs) including pro-inflammatory endothelial-to-mesenchymal transition (EndMT). OSS promoted pro-inflammatory EndMT through the Notch1/p38 MAPK-NF-κB signaling axis. Moreover, OSS-induced EC phenotypic changes resulted in proliferation and extracellular matrix (ECM) protein up-regulation in smooth muscle cells (SMCs) through the RANTES-mediated paracrine mechanism. IL-37 suppressed OSS-induced pro-inflammatory EndMT and thereby abrogated SMC proliferation and ECM protein remodeling. Overall, this study provides insights into endothelial heterogeneity under atheroprone shear stress and identifies the mechanistic role of a novel EC subtype in promoting adverse vascular remodeling. Further, this study demonstrates that anti-inflammatory approach is capable of mitigating vascular pathobiology evoked by atheroprone shear stress.
Negotiating Tension and Change through Religion, Mortuary Practices, and Burial Sites within African-Descent and Moravian Communities in the Caribbean

Historical archaeologies of the African diaspora in the Caribbean have recently expanded on analyses of relationships among religion, mortuary practices, burial sites within varied landscapes, and environmental, social, economic, and cultural contexts. In addition, studies currently investigate the politics of death and burial, including who controlled mortuary spaces, at what times, by which means, and for what purposes. Finally, research collaborations have analyzed community formation and activity through the lens of past and present mortuary practices. In light of these research developments, this article interprets material and documentary evidence to understand how past and present peoples, including enslaved and free people of African descent, Moravian missionaries, and descendant communities, have used religion, burial sites, and mortuary practices to negotiate tension and social change in life and death across landscapes in the British and former Danish West Indies (now the U.S. Virgin Islands).
Glycosylation and disulfide bonding of wild-type SARS-CoV-2 spike glycoprotein.

The SARS-CoV-2 coronavirus, the etiologic agent of COVID-19, uses its spike (S) glycoprotein anchored in the viral membrane to enter host cells. The S glycoprotein is the major target for neutralizing antibodies elicited by natural infection and by vaccines. Approximately 35% of the SARS-CoV-2 S glycoprotein consists of carbohydrate, which can influence virus infectivity and susceptibility to antibody inhibition. We found that virus-like particles produced by co-expression of SARS-CoV-2 S, M, E and N proteins contained spike glycoproteins that were extensively modified by complex carbohydrates. We used a fucose-selective lectin to purify the Golgi-modified fraction of a wild-type SARS-CoV-2 S glycoprotein trimer, and determined its glycosylation and disulfide bond profile. Compared with soluble or solubilized S glycoproteins modified to prevent proteolytic cleavage and to retain a prefusion conformation, more of the wild-type S glycoprotein N-linked glycans are processed to complex forms. Even Asn 234, a significant percentage of which is decorated by high-mannose glycans on other characterized S trimer preparations, is predominantly modified in the Golgi compartment by processed glycans. Three incompletely occupied sites of O-linked glycosylation were detected. Viruses pseudotyped with natural variants of the serine/threonine residues implicated in O-linked glycosylation were generally infectious and exhibited sensitivity to neutralization by soluble ACE2 and convalescent antisera comparable to that of the wild-type virus. Unlike other natural cysteine variants, a Cys15Phe (C15F) mutant retained partial, but unstable, infectivity. These findings enhance our understanding of the Golgi processing of the native SARS-CoV-2 S glycoprotein carbohydrates and could assist the design of interventions. IMPORTANCE The SARS-CoV-2 coronavirus, which causes COVID-19, uses its spike glycoprotein to enter host cells. The viral spike glycoprotein is the main target of host neutralizing antibodies that help to control SARS-CoV-2 infection and are important for the protection provided by vaccines. The SARS-CoV-2 spike glycoprotein consists of a trimer of two subunits covered with a coat of carbohydrates (sugars). Here, we describe the disulfide bonds that assist the SARS-CoV-2 spike glycoprotein to assume the correct shape, and the composition of the sugar moieties on the glycoprotein surface. We also evaluate the consequences of natural virus variation in O-linked sugar addition and in the cysteine residues involved in disulfide bond formation. This information can expedite the improvement of vaccines and therapies for COVID-19.
Investigating landslides caused by earthquakes: A historical review

Post-earthquake field investigations of landslide occurrence have provided a basis for understanding, evaluating, and mapping the hazard and risk associated withearthquake-induced landslides. This paper traces thehistorical development of knowledge derived from these investigations. Before 1783, historical accounts of the occurrence of landslides in earthquakes are typically so incomplete and vague that conclusions based on these accounts are of limited usefulness. For example, the number of landslides triggered by a given event is almost always greatly underestimated. The first formal, scientific post-earthquake investigation that included systematic documentation of the landslides was undertaken in the Calabria region of Italy after the 1783 earthquake swarm. From then until the mid-twentieth century, the best information on earthquake-induced landslides came from a succession ofpost-earthquake investigations largely carried out by formal commissions that undertook extensive ground-based field studies. Beginning in the mid-twentieth century, when the use of aerial photography became widespread, comprehensive inventories of landslide occurrence have been made for several earthquakes in the United States, Peru, Guatemala, Italy, El Salvador, Japan, and Taiwan. Techniques have also been developed for performing ``retrospective'' analyses years or decades after an earthquake that attempt to reconstruct the distribution of landslides triggered by the event. The additional use of Geographic Information System (GIS) processing and digital mapping since about 1989 has greatly facilitated the level of analysis that can applied to mapped distributions of landslides. Beginning in 1984, syntheses of worldwide and national data on earthquake-induced landslides have defined their general characteristics and relations between their occurrence and various geologic and seismic parameters. However, the number of comprehensive post-earthquake studies of landslides is still relatively small, and one of the most pressing needs in this area of research is for the complete documentation of landslides triggered by many more earthquakes in a wider variety of environments.
Epitope tagging for the detection of fusion protein expression in transgenic plants.

Publisher Summary This chapter discusses epitope tagging for the detection of fusion protein expression in transgenic plants. The chapter describes the development of the c-myc epitope tag system for the detection of transprotein expression in transgenic tobacco plants. An expression vector for plant c-myc epitope tagging was constructed and introduced into tobacco plants via Agrobacterium -mediated transformation. The results show that c-myc epitope tagged trans-protein can be detected in extracts from as little as 5 mg of leaf tissue. The Mycl-9El0 monoclonal antibody shows no cross-reactivity to endogenous tobacco or Arabidopsis thaliana proteins. In addition, the antibody can be used to localize expression in various tissues using the tissue print method. The ability of the Mycl-9E10 antibody to detect the 10-amino acid c-myc epitope on Westerns blots and tissue prints and the absence of antibody cross reactivity to endogenous tobacco and Arabidopsis proteins make this epitope–antibody pair an excellent choice as a general marker for protein expression in transgenic plants.
Alternative forms of deposit insurance: Pricing and bank incentive issues

Abstract This paper derives formulas for a deposit insuring agency's liability (and hence a fair value deposit insurance premium) and the equilibrium value of bank equity, considering a wide variety of factors affecting individual bank risk. Both fixed rate and variable rate (risk-sensitive) insurance systems are analyzed. Consideration is made as to whether the deposit insuring agency makes direct payments to depositors or arranges mergers following bank closings. The effect of these various policy choices on banks' incentive for risk taking is also analyzed.
Driving high speed analog to digital converters

Driving high speed Analog to Digital Converters (ADCs) takes more than just shoving a signal into the input. Several aspects ofthe design of the converter must be taken into account. This starts with understanding what type of converter you are using. This will in turn give you a clue to parameters such as input impedance and input voltage ranges, which will influence your selection of amplifier to drive the input. No part can be considered except in the context of the complete system. In this context the author discusses flash converters, high-speed amplifiers, input protection, subranging converters, references, clocks, grounding and power.
Study of SET devices for metrological applications at 0.4 K

Single electron effects have been observed in devices measured at temperatures as low as 0.4 K. The charge noise was measured in electrometers and evidence of background charge fluctuations was observed. Custom-made micro-coax cables have also been fabricated and their measured attenuation is found to increase with the 3/4'th power of frequency, in contrast to the 1/2 power dependence expected from the theory.
Convergent validity in objective measures of identity status: implications for identity status theory

The present study was conducted to test two primary assumptions of Marcia's identity status model: (a) that measures of the identity statuses would relate to identity exploration and commitment in ways consistent with the definitions of the statuses; and (b) that status assignments made using continuous status measures would converge with those made using exploration and commitment scores. Seven hundred fifty-eight university students (174 males, 560 females, 24 not reporting gender) completed the Ego Identity Process Questionnaire, which is a measure of identity exploration and commitment, and the Extended Objective Measure of Ego Identity Status II, which provides continuous measures of each identity status. Results provided mixed support for both assumptions of the identity status model. The findings are discussed in light of recent calls for expansion of identity theory and research beyond the identity status model.
Robo2 acts in trans to inhibit Slit-Robo1 repulsion in pre-crossing commissural axons

During nervous system development, commissural axons cross the midline despite the presence of repellant ligands. In Drosophila, commissural axons avoid premature responsiveness to the midline repellant Slit by expressing the endosomal sorting receptor Commissureless, which reduces surface expression of the Slit receptor Roundabout1 (Robo1). In this study, we describe a distinct mechanism to inhibit Robo1 repulsion and promote midline crossing, in which Roundabout2 (Robo2) binds to and prevents Robo1 signaling. Unexpectedly, we find that Robo2 is expressed in midline cells during the early stages of commissural axon guidance, and that over-expression of Robo2 can rescue robo2-dependent midline crossing defects non-cell autonomously. We show that the extracellular domains required for binding to Robo1 are also required for Robo2's ability to promote midline crossing, in both gain-of-function and rescue assays. These findings indicate that at least two independent mechanisms to overcome Slit-Robo1 repulsion in pre-crossing commissural axons have evolved in Drosophila.
Rotor field oriented control of five-phase induction motor with the combined fundamental and third harmonic currents

This paper presents an application of rotor field oriented control (RFOC) to a five-phase induction motor with the combined fundamental and third harmonic currents. Based on the motor model developed in a new d/sub 1/q/sub 1/d/sub 3/q/sub 3/n reference frame, the complete theory and modeling of rotor field oriented control of the five-phase induction motor are established. Specifically, investigation is made to improve power density and output torque of the five-phase induction motor by injecting third harmonic currents. By the proper dynamical adjustment and steady state compensation, the rotor field oriented control of the five-phase induction motor not only achieves a high drive performance, but also controls the fundamental and third harmonic flux and torque to generate the desired nearly rectangular air-gap flux. Both simulation and experimental results further verify the theoretical analysis and demonstrate the feasibility and practical value of the proposed five-phase induction motor drive.
Is Prevention of Ventilator- Associated Pneumonia Cost Effective?

The prevention of VAP appears to be a cost effective endeavor based on the healthcare costs and morbidity associated with this nosocomial infection. Infection control measures should be integrated into a systematic program for general application to all patients requiring mechanical ventilation at a particular hospital (36,37). Additionally, attention needs to be focused on the emergence of antibiotic-resistant bacterial infections in the intensive care unit setting (87,88). The prevention of antibiotic-resistant bacterial infections should result in fewer overall nosocomial infections including VAP (75). At present, VAP prevention programs should employ practices which are readily accepted by local practitioners, safe for patients, and associated with acceptable costs to the institution.
A Maximum Power Tracking Technique for Grid-Connected DFIG-Based Wind Turbines

In this paper, a maximum power tracking technique is presented for doubly fed induction generator-based wind turbines. The presented technique is a novel version of the conventional method, i.e., the electrical torque is proportional to the square of the rotor speed, in which the proportional coefficient is adaptively adjusted in real-time through three control laws. The first control law calculates the desired electrical torque using feedback linearization, assuming that the power capture coefficient and the desired rotor speed are instantaneously identified. The second control law estimates the real-time values of the power capture coefficient from a Lyapunov-based analysis, and the third control law provides the desired rotor speed. These control laws cause the turbine to adaptively adjust the rotor speed toward a desired speed in which the operating point moves in the direction of increasing the power capture coefficient. The proposed maximum power tracking method differs distinctly from the perturb-and-observe scheme by eliminating a need for adding a dither or perturbation signal, and robustly tracks the trajectory of maximum power points even in the event of a sudden wind speed change that can cause the perturb-and-observe technique to fail. In this paper, the National Renewal Energy Laboratory 5-MW reference wind turbine model is used to demonstrate the validity and robustness of the proposed method.
Biliary excretion of insulin in the adult chicken.

Abstract Avian clearance of 125I labeled and unlabeled insulin was evaluated in adult female chickens with cannulae inserted in the hepatoenteric bile duct. The results obtained indicated: 1. 1. Biliary excretion is a feasible mechanism for the removal of insulin in chickens. 2. 2. Biologically active insulin is present in the bile of normal and tolbutamide injected chickens. 3. 3. The amount of insulin removed by the liver/bile amounted to less than 0·5 per cent of an injected dose. 4. 4. Conclusion: insulin is excreted in avian bile normally; however, this mechanism plays a minor role in the reported “avian resistance” to insulin.
Stereo Vision Based Road Surface preview

Road surface preview is an application where road surface elevation profile in front of the host vehicle is estimated, whereby bumps and potholes can be detected for active suspension control and roadway maintenance. In this paper, the authors describe a stereo vision system that performs road surface preview along the host vehicle path. Real-time three dimensional (3D) road surface reconstruction was calculated from stereo range images at centimeter scale to provide elevation profiles along predicted tire tracks. Camera pitch angle is dynamically estimated, which is used to correct elevation errors caused by host vehicle pitching up and down on the roadway. Having been implemented in embedded hardware and tested in passenger vehicles, the described system showed good performance for various road conditions and on different road surfaces (asphalt, concrete, and dirt roads).
Dynamic combinatorial key management scheme for sensor networks

Securing sensor networks has received much attention in the last few years. In a typical field deployment, a sensor network self-organizes, closely interacts with its physical environment, and works unattended possibly in a hostile environment such as a battlefield. In such environments, sensor networks are subject to node capture as well as a myriad of other attacks. Constrained energy, memory, and computational capabilities of sensor nodes mandate a clever design of security solutions to minimize overhead while maintaining secure communications over the lifespan of the network. In this paper, we propose a Dynamic Combinatorial Key management scheme, DCK, to provide efficient, scalable, and survivable dynamic keying in a clustered sensor network with a large number of sensor nodes. DCK employs the Exclusion-Basis Systems (EBS) as the underlying framework for key management at both the cluster and the sensor node levels. DCK enhances network security by localizing cluster key management functions, thus, limiting the impact of sensor node capture to the attacked cluster. Within a cluster, DCK decouples key generation, assignment, and distribution, and distributes the key management tasks among cluster nodes. Simulation results show that DCK is efficient in terms of energy consumption and storage. Also, it significantly outperforms other dynamic keying schemes, in particular with regards to energy consumed in key refreshment and re-keying after node capture. Copyright © 2006 John Wiley & Sons, Ltd.
Population genomics: patterns of genetic variation within populations

Population genomics is the study of the forces that shape the distribution of molecular variation within and among populations, on a genome-wide scale (Luikart et al., 2003). Throughout the twentieth century, the mathematical theory of the history and fate of alleles became increasingly sophisticated, to the point where it was recognized that multiple gene sequences are required to describe the history or demography of a species (Hey and Machado, 2003) and that properties of single genes must be interpreted in light of other sequences (Chakravati, 1999; Bamshad and Wooding, 2003). While robust evolutionary theory from first principles is essential for the interpretation of the distribution of genetic variation (Kimura, 1983; Hartl and Clark, 1997), it must be supplemented by empirical data that places confidence limits on key parameters. That these vary widely among species is one of the important insights from genomic analysis, which is thus ushering in a dramatic new phase in the discipline of population genetics.
Sn/C composite anodes for Li-ion batteries

Composites of Sn/C were synthesized by infiltrating tetraethyltin into mechanically milled polystyrene resin powder. Heat-treatment of the precursor in Ar atmosphere at 600°C results in crystalline tin and amorphous carbon. The resultant composite exhibits a capacity of 480 mAh/g with good capacity retention (0.15% loss/cycle). Transmission electron microscopy analysis indicates nanocrystalline (∼200 nm) spherical tin particles embedded in large carbon particles (=2 to 10 μm). The embedment of nanocrystalline tin within carbon appears to be the main reason for the good cyclability suggesting the excellent potential of these Sn/C based composites for use as alternative anodes for lithium-ion batteries.
Stimulation of prostaglandin E2 synthesis in human amnion cells maintained in monolayer culture by a substance(s) in amniotic fluid

A substance(s) in amniotic fluid of human pregnancies promotes a striking increase in prostaglandin E2 production in human amnion cells maintained in primary monolayer culture. The prostaglandin E2 synthesis-stimulatory factor(s) acts in a time- and dose-dependent manner to accelerate prostaglandin E2 formation. We suggest that a substance of fetal origin enters amniotic fluid by way of fetal urine and acts to regulate prostaglandin E2 synthesis in amnion. Such a process may be of fundamental importance in the regulation of amniotic fluid volume homeostasis and in the initiation of parturition.
Abridgment of heat losses in D-C. armature conductors

Without doubt, it is generally believed that there are extra losses in the armature coil of a d-c. machine when it is undergoing commutation, but that during the major portion of the time, since the current is steady, the loss in the coil is correctly computed by squaring the value of the current and multiplying by the true or ohmic resistance of the coil. This view, however, is not correct. The disturbance in the coil current produced by the process of commutation persists throughout the cycle so that at no time is the current uniformly distributed over the cross-section of the conductor. Although the disturbance and resulting extra loss factor are greatest during commutation, the extra losses are present at all times, even while the current in the coil is steady.
Size-dependent deposition of particles in the human lung at steady-state breathing

Abstract Numerous efforts have been made to model particle deposition in the human lung and to characterize regional deposition based on a single breath. However, over successive breathing cycles, accurate estimates of regional particulate dosimetry for long-term PM exposures cannot be elucidated without considering transport and deposition of the retained particles especially those in 0.1– 1 μ m size range. We estimated the total and regional dosimetry of 0.01– 10 μ m particles after the lung attains a steady state during multiple breathing cycles by employing a semi-empirical model developed in previous work [Park, S. S., & Wexler, A. S. (2007a). Particle deposition in the pulmonary region of the human lung: A Semi-empirical model of single breath transport and deposition. Journal of Aerosol Science, 38(2), 228–245; Park, S. S., & Wexler, A. S. (2007b). Particle deposition in the pulmonary region of the human lung: Multiple breath aerosol transport and deposition. Journal of Aerosol Science, 38(5), 509–519]. To understand the influence of alveolar wall motion to deposition of different sized particles, local alveolar entering probabilities of 0.5 μ m particles suggested by Haber et al. [2003. Gravitational deposition in a rhythmically expanding and contracting alveolus. Journal of Applied Physiology, 95(2), 657–671] were used to estimate the enhanced gravitational deposition efficiencies of other particle sizes. Increased deposition fractions are predicted for 0.1– 10 μ m particles with Haber et al.'s gravitational efficiency during both single and multiple breathing cycles. There are only slight increases in the pulmonary deposition of ultrafine and 1– 10 μ m particles during multi-breaths compared to that on single breath because the vast majority deposit on the first breath leaving very few in retained air. As for fine particles (0.1– 1 μ m ), the multi-breath pulmonary deposition fraction is about two times higher than the results from single breath simulation due to the deposition of particles that were retained from the previous breath. Since fine-mode particles have the lowest deposition efficiency, considering combined effect of three major deposition mechanisms, the retained fractions at the end of exhalation are significantly higher (14–32%) than the ones during a single breath. Therefore, these retained fractions have to be considered for the estimation of particle dosimetry in humans to evaluate long-term PM exposure.
Altered information transfer in neuronal networks marks pathology

Understanding how information flowing in neuronal networks is encoded by populations of neurons is a fundamental problem in neuroscience. Brains and neuronal networks must at the same time store information about the world and react to information in the world. We used simulations of neocortical columns to measure how the activity of the network alters information flow and related this to experimental data from animal models of epilepsy and schizophrenia. In our simulations, we found that networks with greater internal connectivity reduced information flow from inputs to outputs, measured by normalized transfer entropy [1]. With no internal connectivity, the feed-forward network transformed inputs through nonlinear summation and thresholding. With greater connectivity strength, the recurrent network translated activity and information due to contribution of activity from intrinsic network dynamics. This dynamic contribution amounted to added information coming from the network. Gradual reduction in information flow-through with increased internal weight was asymptotic. At one extreme, the highly interconnected network was epileptic and any input ignited a seizure [2]. Such networks no longer accepted external information and no longer coordinated well with other brain areas. These types of networks also had more stereotyped activity patterns, with lesser information content present in the network and minimal information communicated from outside. EEG data from an animal model of epilepsy showed a similar reduction in entropy, which was also accompanied with a decrease in coordination between different brain areas. At a lower level of dynamic pathology, abnormalities in power and coordination in gamma bands were seen, as has been noted in schizophrenia [3-5]. In schizophrenia, the core cognitive deficit is believed to be a problem of coordinating external and internal states to provide a coherent view of the world, and the person's relation to the world [6]. This is most evident with hallucinations, a mistaken attribution of internal activity to the external world. EEG data from an animal model of schizophrenia showed increased correlation between the power of oscillations in the gamma and beta bands, suggesting an over-reliance on internal information. This is analogous to the over reliance on internal information in our simulations of networks with overly high internal connectivity. Our simulations provide a framework for relating aspects of epilepsy and schizophrenia to information processing. By quantifying the competing effects of internal and external information sources in simulation, we can suggest how symptoms of these disorders may be produced.
Piaget's epistemic subject and science education: Epistemological vs. psychological issues

Many individuals claim that Piaget's theory of cognitive development is empirically false or substantially disconfirmed by empirical research. Although there is substance to such a claim, any such conclusion must address three increasingly problematic issues about the possibility of providing an empirical test of Piaget's genetic epistemology: (1) the empirical underdetermination of theory by empirical evidence, (2) the empirical difficulty of testing competence-type explanations, and (3) the difficulty of empirically testing epistemic norms. This is especially true of a central epistemic construct in Piaget's theory — the epistemic subject. To illustrate how similar problems of empirical testability arise in the physical sciences, I briefly examine the case of Galileo and the correlative difficulty of empirically testing Galileo's laws. I then point out some important epistemological similarities between Galileo and Piaget together with correlative changes needed in science studies methodology. I conclude that many psychologists and science educators have failed to appreciate the difficulty of falsifying Piaget's theory because they have tacitly adopted a philosophy of science at odds with the paradigm-case of Galileo.
Models provide specificity: Testing a proposed mechanism of visual working memory capacity development.

Abstract Numerous studies have established that visual working memory has a limited capacity that increases during childhood. However, debate continues over the source of capacity limits and its developmental increase. Simmering (2008) adapted a computational model of spatial cognitive development, the Dynamic Field Theory, to explain not only the source of capacity limitations but also the developmental mechanism. Capacity is limited by the balance between excitation and inhibition that maintains multiple neural representations simultaneously in the model. Development occurs according to the Spatial Precision Hypothesis, which proposes that excitatory and inhibitory connections strengthen throughout early childhood. These changes in connectivity result in increasing precision and stability of neural representations over development. Here we test this developmental mechanism by probing children's memory in a single-item change detection task. Results confirmed the model's predictions, providing further support for this account of visual working memory capacity development.
Chromomagnetic energy of SU(2) gauge fields on a torus

Abstract Inspired by the Savvidy-Copenhagen vacuum picture, we present a calculation of the chromomagnetic energy of pure SU(2) gauge fields defined on a torus. We avoid the perturbative instability of the Savvidy state by introducing magnetic flux through 't Hooft's twisted boundary conditions. The energy as a function of magnetic flux and volume is calculated to two-loop order. Nonperturbative effects related to tunneling processes are briefly discussed. We consider this calculation as a first step in a program aimed at exhibiting possible instabilities of the perturbative vacuum.
Algebra Structures on Resolutions of Rings Defined by Grade Four Almost Complete Intersections

Abstract Let (R, m , k) be a local ring in which 2 is a unit and let J be an indeal in R. The minimal R-free resolution of R/J is called a DG-algebra if it has the structure of an associative, differential, graded commutative algebra over R. If J is a grade four almost complete intersection ideal in R, then J is necessarily linked to a grade four Gorenstein ideal I by a grade four complete intersection K. It is well known that the minimal R-free resolutions of R/I and R/K admit DG-algebra structures. In this paper, we show that if W denotes the image of the map TorR1(R/K, k) → TorR1(R/I, k) and W2 = 0 (for example, if K ⊆ m I), then the minimal R-free resolution of S = R/J has a DG-algebra structure. In the case where the ring R is regular local and K ⊆ m I we prove that the Poincare series PNS(t) of every finitely generated S-module N is rational and the ring S satisfies the Eisenbud Conjecture.
Measurement error models

Abstract An overview is given of linear measurement error models. Such models appear in many forms, including errors-in-variables regression and factor analysis, but are mathematically related to each other. Of particular interest to chemists are mass balance receptor models in which source profiles are estimated with error. A general model is given for errors in profiles, and the attention of chemists is directed toward recent advances in statistical model fitting and numerical analysis which may be of use in estimating source contributions.
Matrix metalloproteinase inhibition suppresses MMP-2 activity and activation of PANC-1 cells in vitro.

Abstract Background. We have shown previously that the metalloproteinase inhibitor, BB-94, prolongs survival and attenuates MMP-2 activity in a murine model of pancreatic cancer. The purpose of this study was to determine the effect of BB-94 on the activity and activation of MMP-2 by PANC-1 cells in vitro. Materials and methods. The poorly differentiated pancreatic cancer cell line PANC-1 was stimulated in vitro with the phorbol ester PMA (20 nM) and grown in the presence of increasing doses of BB-94 (0, 40, 200, and 400 ng/ml) for 24 h. Activation of MMP-2 was determined by gel zymography. In a separate experiment detailing the effects of BB-94 on MMP-2 activity, PANC cells were stimulated for 24 h with PMA and run out on four separate zymograms, each incubated in the previously noted concentrations of BB-94. Using densitometry, band intensity on all gels was determined and compared for each concentration of BB-94. The Matrigel assay was used to determine BB-94's effect on the invasive potential of PANC cells at the previously studied concentrations. The presence of MT-MMP (a putative component of MMP-2 activation) was confirmed using Western blot in each group. Results. BB-94 inhibited the conversion of latent to active MMP-2 in a dose-dependent fashion. BB-94 also inhibited the activity of MMP-2 when run out on gel zymograms incubated with increasing concentrations of BB-94. Decreased activity and activation of MMP-2 by BB-94 were manifested by a significant reduction in the invasive potential of PANC as determined by the Matrigel assay. MT-MMP was universally present in each study group. Conclusions. The previously described salutary effects of MMP blockade in mice implanted with pancreatic cancer can be explained in vitro by a dose-dependent diminution of MMP-2 activity and activation in PANC cells exposed to BB-94.