cssi/SciSciGPT-SciSciNet huggingface dataset:
Primary Repair of the Medial Collateral Ligament With Internal Bracing

The medial collateral ligament (MCL) is commonly injured in the setting of anterior cruciate ligament (ACL) injuries. Because the MCL has better healing capacity than the ACL, the general perception is that MCL injuries can be treated conservatively. Treating these injuries conservatively, however, can lead to residual valgus laxity. Furthermore, it delays time to surgery, which prevents acute treatment of concomitant ACL injuries using primary repair or acute reconstruction. Several treatment methods for MCL injuries have been proposed, including primary repair, augmented repair with autograft tissue, or primary reconstruction. In this surgical technique article, we present the technique of acute primary MCL repair with internal bracing with 2 limited incisions. With this technique, early surgical intervention is possible, and early rehabilitation is safe because of the internal bracing. Advantages include fast recovery, avoidance of muscle atrophy because of early mobilization, prevention of residual valgus instability, and maintenance of proprioception.
Dynamical Links between the Decadal Variability of the Oyashio and Kuroshio Extensions

AbstractRather than a single and continuous boundary current outflow, long-term satellite observations reveal that the Oyashio Extension (OE) in the North Pacific Subarctic Gyre comprises two independent, northeast–southwest-slanted front systems. With a mean latitude along 40°N, the western OE front exists primarily west of 153°E and is a continuation of the subarctic gyre western boundary current. The eastern OE front, also appearing along 40°N, is located between 153° and 170°E, whose entity is disconnected from its western counterpart. During 1982–2016, both of the OE fronts exhibit prominent decadal fluctuations, although their signals show little contemporaneous correlation. An upper-ocean temperature budget analysis based on the Estimating the Circulation and Climate of the Ocean, phase II (ECCO2), state estimate reveals that the advective temperature flux convergence plays a critical role in determining the low-frequency temperature changes relating to the OE fronts. Specifically, the western OE f...
Blue-Agave Fiber-Reinforced Polypropylene Composites for Automotive Applications

As consumer demand for more fuel-efficient vehicles increases, automakers are looking for innovative ways to reduce the weight of vehicles. Many automotive-grade plastics contain traditional reinforcing fillers, such as glass or talc, to improve the mechanical properties of the material. By replacing these high-density fillers with natural fibers, the material and corresponding weight can be reduced, which results in an improvement of the vehicle fuel economy. The objective of this study was to investigate the use of blue-agave bagasse fibers, which was sourced from tequila manufacturing waste, as a reinforcing agent in polypropylene composites. The effects of the fiber processing method, fiber loading level, and addition of a compatibilizer (polypropylene-grafted maleic anhydride) on the composite properties were determined. Samples were produced via twin-screw extrusion and injection molding. The resulting mechanical properties and morphology of the fracture surfaces were investigated. The fiber processing method (Agave C vs. Agave R) did not significantly affect the composite properties. Higher loading levels of fiber reduced both the elongation at break and impact strength, but increased the stiffness of the agave composites. The compatibilizer increased the fiber matrix adhesion, but reduced impact strength because the polymer matrix was softened.
Thalamic Control of Cognition and Social Behavior Via Regulation of Gamma-Aminobutyric Acidergic Signaling and Excitation/Inhibition Balance in the Medial Prefrontal Cortex

Abstract Background The mediodorsal thalamus plays a critical role in cognition through its extensive innervation of the medial prefrontal cortex (mPFC), but how the two structures cooperate at the single-cell level to generate associated cognitive functions and other mPFC-dependent behaviors remains elusive. Maintaining the proper balance between excitation and inhibition (E/I balance) is of principal importance for organizing cortical activity. Furthermore, the PFC E/I balance has been implicated in successful execution of multiple PFC-dependent behaviors in both animal research and the context of human psychiatric disorders. Methods Here, we used a pharmacogenetic strategy to decrease mediodorsal thalamic activity in adult male rats and evaluated the consequences for E/I balance in PFC pyramidal neurons as well as cognition, social interaction, and anxiety. Results We found that dampening mediodorsal thalamic activity caused significant reductions in gamma-aminobutyric acidergic signaling and increased E/I balance in the mPFC and was concomitant with abnormalities in these behaviors. Furthermore, by selectively activating parvalbumin interneurons in the mPFC with a novel pharmacogenetic approach, we restored gamma-aminobutyric acidergic signaling and E/I balance as well as ameliorated all behavioral impairments. Conclusions These findings underscore the importance of thalamocortical activation of mPFC gamma-aminobutyric acidergic interneurons in a broad range of mPFC-dependent behaviors. Furthermore, they highlight this circuitry as a platform for therapeutic investigation in psychiatric diseases that involve impairments in PFC-dependent behaviors.
Reel simulations: CGI and special effects in two films by Paolo Sorrentino

Criticism on two recent films by director Paolo Sorrentino (La grande bellezza, 2013; Youth, 2015) has tended to identify them with a formalistic retreat from the afflicted state of the Italian nat...
Optimal Bayesian Classification With Missing Values

Missing values can be an impediment to designing and applying classifiers. Missing values are common in biomedical studies due to various reasons, including missing tests or complex profiling technologies for different omics measurements in modern biomedicine. Many procedures have been proposed to impute values that are missing. This paper considers missing feature values in the context of optimal Bayesian classification, which selects a classifier that minimizes the expected error with respect to the posterior distribution governing an uncertainty class of feature-label distributions. The missing-value problem fits neatly into the overall framework of optimal Bayesian classification by marginalizing out the missing-value process from the feature-label distribution, and then updating the prior distribution of class-conditional parameters to posterior distributions using new observations. Generally, an optimal Bayesian classifier is defined via the effective class-conditional densities, which are averages of the parameterized feature-label distributions in the uncertainty class relative to the posterior distribution. Hence, once the posterior distribution incorporating the missing value process is found, the optimal Bayesian classifier pertaining to the features with missing values can be derived from the corresponding effective class-conditional densities. This paper presents the general theory, derives a closed-form decision rule for the optimal Bayesian classifier in a Gaussian model with independent features, and utilizes Hamiltonian Monte Carlo for the Gaussian model with arbitrary covariance matrices. Superior performance is demonstrated when compared to linear discriminant analysis, quadratic discriminant analysis, and support vector machines in conjunction with Gibbs sampling imputation using synthetic and real-world omics data.
Constructions by Straightedge and Compass in the Hyperbolic Plane

As in the Euclidean case, questions of constructibility by straightedge and compass involve consideration of certain algebraic number fields called quadratic-surd fields. They are obtained by starting with the rational field and adjoining square roots in succession. Roughly speaking, a point with polar coordinates r, θ can be constructed in the Euclidean case if r and sin θ are in such a field (in which case cos θ and tan θ are also in such a field), while in the hyperbolic case, the point can be constructed if tanh r and sin θ are in such a field. The first two sections give the proof (which is not short) that if the point can be constructed, then tanh r and sin θ are in a quadratic-surd field. Section 11.6 contains the proof (also not short) that every such point can be constructed. As a result, there are certain differences between Euclidean and the hyperbolic cases. In the hyperbolic case, a segment cannot in general be trisected, while some circles can be squared (that depends on the radius). In the general theory, the constructions start with a single given line and a single given point on that line, but no segment of unit length, because a unit of length is implied by the hyperbolic axioms. Certain construction problems are considered in which other things are given in advance, for example constructing the angle of parallelism II (y), when a segment of length y is given. Since any two ideal points in the hyperbolic plane determine a unique line, it is assumed that the straightedge can draw the line between any two ideal points, but it is shown in Section 11.9 that that is not really necessary. All constructions can be made (with more trouble) if the straightedge is only assumed to be able to draw a line between any two finite points. The purpose of the last section is to show that constructibility is not merely a matter of interest for engineering or draftsmanship, but also throws light on the geometry itself. The set of constructible points (it is a countable set!) constitutes a geometry that satisfies all the axioms of the hyperbolic plane, except that there is no axiom of completeness, either for the real number system ℝ or for the points on a line. (Those axioms are of course not categorical, since, in particular, the ordinary hyperbolic plane satisfies them.)
An Object-Oriented Paradigm for the Design of Realistic Neural Simulators

An object-oriented programming approach is used to implement a generic neural simulator to simulate the electrophysiological properties of neurons and interconnected neuronal networks. The neural simulator is designed with a generalizable principle to encourage users to make additions and modifications to the existing neurophysiological models. The object-oriented programming paradigm is used extensively to encapsulate the similarities and differences between different neurons and their components by various “objects”. A neuron is constructed by a compartmental model where electrical properties of the membrane of a neuron are compartmentalized and then linked together to form a whole neuron. Similarly, an equivalent of a biological neural network can constructed by connecting model neurons together to form a network. The object-oriented approach is used not only in constructing the neuronal structural hierarchy but also in the methods for solving mathematical equations governing the electrical properties of the neurons. Using these principles, a truly generic and generalizable model for simulating neuronal properties is accomplished.
Security namespace: making Linux security frameworks available to containers

Lightweight virtualization (i.e., containers) offers a virtual host environment for applications without the need for a separate kernel, enabling better resource utilization and improved efficiency. However, the shared kernel also prevents containers from taking advantage of security features that are available to traditional VMs and hosts. Containers cannot apply local policies to govern integrity measurement, code execution, mandatory access control, etc. to prevent application-specific security problems. Changes have been proposed to make kernel security mechanisms available to containers, but such changes are often adhoc and expose the challenges of trusting containers to make security decisions without compromising host system or other containers. In this paper, we propose security namespaces, a kernel abstraction that enables containers to have an autonomous control over their security. The security namespace relaxes the global and mandatory assumption of kernel security frameworks, thus enabling containers to independently define security policies and apply them to a limited scope of processes. To preserve security, we propose a routing mechanism that can dynamically dispatch an operation to a set of containers whose security might be affected by the operation, therefore ensuring the security decision made by one container cannot compromise the host or other containers. We demonstrate security namespace by developing namespaces for integrity measurement and mandatory access control in the Linux kernel for use by Docker containers. Results show that security namespaces can effectively mitigate security problems within containers (e.g., malicious code execution) with less than 0.7% additional latency to system call and almost identical application throughput. As a result, security namespaces enable containers to obtain autonomous control over their security without compromising the security of other containers or the host system.
Radio frequency identification to measure the duration of machine-paced assembly tasks: Agreement with self-reported task duration and application in variance components analyses of upper arm postures and movements recorded over multiple days.

Abstract Technical advances in inertial measurement units (IMUs) with data logging functionality have enabled multi-day collection of fullshift upper arm postures and movements. Such data are useful for characterizing job-level exposures and, when coupled with task-level information, can inform interventions to mitigate high-exposure tasks. Previously reported methods for capturing task-level information, however, were limited primarily to self-report diaries or direct observation. In this study of machine-paced manufacturing workers (n=6), a low-cost radio frequency identification (RFID) system was used to collect information about when, and for how long, specific assembly tasks were performed during up to 14 consecutive work shifts (76 total work shifts across the six participants). The RFID data were compared to information collected with a self-report diary using Bland-Altman analyses. In addition, the RFID data were paired with IMU data to identify task-level exposures from within full-shift recordings of upper arm postures and movements. These data were then used to estimate the relative contributions of between- and within-worker sources of variance to overall variance in posture and movement summary measures using hierarchical random-effects analysis of variance (ANOVA) techniques. Average estimates of daily task duration based on RFID data were comparable to estimates obtained by self-report (mean bias ±100 minutes). In addition, the ANOVA models containing task-level information suggested a substantial amount of the overall exposure variance was attributed to repeated observations of the same task within a work day. These findings (i) suggest that while the RFID system used in this study performed adequately, further refinement, validation, and/or alternative strategies may be needed and (ii) underscore the importance of repeated full-shift and task-based measurement approaches in characterizing physical exposures, even in machine-paced environments.
Cerebral blood flow is not modulated following acute aerobic exercise in preadolescent children.

Abstract Cognitive enhancements following a single bout of exercise are frequently attributed to increases in cerebral blood flow, however to date we have little understanding of the extent to which such bouts of exercise actually even influence cerebral blood flow following the cessation of exercise. To gain such insight, both regional and global changes in cerebral blood flow were assessed using 3D pseudo-continuous arterial spin-labeled magnetic resonance imaging in a sample of 41 preadolescent children. Using a within-participants randomized crossover design, cerebral blood flow as assessed prior to and following 20-min of either aerobic exercise or an active-control condition during two separate, counterbalanced sessions. The aerobic exercise condition consisted of walking/jogging on a motor driven treadmill at an intensity of approximately 70% of age-predicted maximum heart rate (HR = 136.1 ± 11.1 bpm). The active control condition consisted of walking on the treadmill at the lowest possible intensity (0.5 mph and 0% grade; HR = 92.0 ± 12.2 bpm). Findings revealed no differences in cerebral blood flow following the cessation of exercise relative to the active control condition. These findings demonstrate that cerebral blood flow may not be altered in preadolescent children following the termination of the exercise stimulus during the period when cognitive enhancements have previously been observed.
Autoproducts and out-of-band acoustic fields in refracting multipath environments with caustics

Autoproducts are nonlinear mathematical constructions developed from a given acoustic field with non-zero bandwidth that can—with some limitations—mimic lower and higher frequency acoustic fields lying outside the bandwidth of the given acoustic field. The autoproducts’ mimicry of out-of-band fields is often sufficient for successful beamforming and/or source localization at below- or above-band frequencies chosen to correct array sparseness, suppress random scattering, mitigate environmental mismatch, and/or enhance resolution. While the limitations of autoproducts developed from acoustic fields well-described by ray acoustics are understood, what is less studied are the effects of diffraction and refraction. In this presentation, acoustic waveguide environments are defined which contain strong refraction, and form caustics—regions where nearby ray paths cross—which results in a phase shift in the propagating waves. These caustic phase shifts are not found in autoproduct fields and are detrimental for autoproduct-based remote sensing, especially in regions that are reached by multiple rays that have passed through different numbers of caustics. Multiple refracting environments are considered, including n2-linear and n2-quadratic sound speed profiles, and the ability of autoproducts to mimic out-of-band fields in these environments is assessed. Implications for autoproduct-based source localization are discussed. [Sponsored by ONR and NSF.]
Phacoemulsifier occlusion break surge volume reduction.

Purpose To compare the volumetric occlusion break surge responses of phacoemulsification units from 1 company over 3 generations under varying vacuum limits and target intraocular pressure (IOP) settings. Setting Alcon Research, Ltd., Lake Forest, California, USA. Design Experimental study. Methods Three generations of phacoemulsification units (Infiniti Vision System, Centurion Vision System, and Centurion Vision System with Active Sentry upgrades) were tested. Volumetric surge responses were measured after occlusion breaks at vacuum limits of 200 mm Hg, 300 mm Hg, 400 mm Hg, 500 mm Hg, and 600 mm Hg and target IOPs of 30 mm Hg, 55 mm Hg, and 80 mm Hg. An acrylic test chamber with a piston attached to 3 springs modeled the human eye in this study. The springs were calibrated to mimic volumetric changes in the eye over a wide range of IOPs. Results Occlusion break surge volumes varied from 17.4 μL to 153 μL, corresponding to 7% and 61%, respectively, of the aqueous volume in the average phakic eye and to 4% and 33% of the aqueous volume in the average aphakic eye. Conclusion Occlusion break surge volumes decreased with increasing target IOP, decreasing vacuum limit, and each generational increment in the phacoemulsification system.
Frequency of Instructor- and Student-Centered Teaching Practices in Introductory CS Courses

Despite growing promotion of student-centered teaching, few studies have assessed how widely these practices have diffused throughout computer science (CS) higher education. Studies on teaching practices often treat instructor- and student-centered learning as being dichotomous. Recent research indicates that this reductionist model misinterprets what actually goes on in CS classrooms. For example, a recent study found that most CS faculty categorized their teaching practices as equally student-centered and instructor-centered. We contribute to this scholarship by reporting the results of a survey disseminated to 821 CS educators in 595 universities, colleges, and community colleges in the U.S. Participants were asked to report how frequently they employed several instructor- or student-centered teaching practices and tools during the most recent semester that they taught a specific course. Results indicate that when asked to reflect on specific behaviors within a certain timeframe, faculty reported using instructor-centered teaching practices, especially delivering content via lecture, more than student-centered practices. However, most faculty also reported using at least one student-centered technique, albeit less frequently, throughout the semester. This study found few differences across certain situational and demographic variables (e.g., institution type, tenure status, etc.). Faculty justify their teaching choices with concern for negative evaluations, desire for student learning, large enrollments, heavy teaching loads, and retaining underrepresented students.
Secure Blockchain-Enabled DyMonDS Design

In this paper, we propose a secure system design for implementing the minimal-information exchange framework to efficiently provide services; the application of this concept is in the context of electricity services. The information being exchanged is dictated by the Dynamic Monitoring and Decision Systems (DyMonDS) platform, which enables optimal global solutions to be derived even in a largely distributed setting. This capability parallels the increasing number of smart Internet of Things (IoT) devices that allow for a responsive and flexible service. These advancements are aligned in the Secure Blockchain-Enabled DyMonDS design, where a secure communication protocol enables smart embedded devices to communicate with local compute nodes; these compute nodes are connected in a meshed blockchain network, providing information security, integrity, and robustness.
Nonlinear response in a noncentrosymmetric topological insulator

Nonlinear phenomena are inherent in most systems in nature. Second- or higher-order harmonic generations, three-wave mixing, and four-wave mixing are typical phenomena in nonlinear optics. To obtain a nonzero signal for second-harmonic generation in the long-wavelength limit ($q\ensuremath{\rightarrow}0$), the breaking of inversion symmetry is required. In topological materials, a hexagonal warping term that breaks the rotation symmetry of the Fermi surface is observed by angular-resolved photoemission spectroscopy. If a gap opens (e.g., by doping with magnetic impurities), the inversion symmetry will be broken. Here we use a nonlinear response theory based on a generalized Kubo formula to explain the frequency up-conversion in topological materials.
Plane Wave Reflection and Refraction

A practical problem of fundamental importance in electromagnetic wave theory concerns the reflection and transmission of an electromagnetic wave at an interface separating two different material media. As this problem can become rather complicated for a general pulsed wave field incident upon the surface S of a dispersive body immersed in a dispersive medium, it is best to consider first the much simpler case of a time-harmonic (monochromatic) plane wave field incident upon an infinitely extended plane surface. The general solution to this problem will then form the basis for the analysis of the more general problem of a pulsed electromagnetic beam field incident upon a planar interface separating two different dispersive media. This more general problem is treated in some detail in Volume 2.
Land-Grant Colleges and Popular Revolt: The Origins of the Morrill Act and the Reform of Higher Education

Nathan M. Sorber’s analysis of land-grant colleges in the Northeast begins with a fascinating story. In 1888, agrarian interests within the state of Vermont hoped to remove Morrill Act funds from t...
A phase field model for dislocations in hexagonal close packed crystals

Abstract In this work, an application of a phase field formulation suitable for modeling the motion of individual partial and full dislocations in hexagonal close packed (HCP) crystals is presented. The formulation incorporates periodic potentials for glide on the distinct HCP slip systems, which are informed here by density functional theory (DFT). The model is applied to simulate the dissociation process starting from an unstable perfect dislocation and ending at its final equilibrium structure for different slip planes and in different HCP metals. The structural characteristics that are predicted for these dislocations include the partial Burgers vectors, dissociation distances, core widths of the partials, and any asymmetries in these quantities. Mg is selected as one of the model materials since its dislocations are the most well studied and it is nearly elastically isotropic. For Mg, it is shown that the predictions for dissociation distances agree with those reported previously by atomic-scale calculations, including density functional theory, for dislocations on the basal , prismatic , and pyramidal type II c + a > slip systems. Phase field model results are also presented for dislocations in Ti and Zr, which we find develop distinctively different equilibrium structures than Mg.
Abstract TP146: Rate of Functional Improvement for Stroke Patients Plateaus During Inpatient Rehabilitation

Introduction: Functional outcomes and length of stay (LOS) are common outcome measures in stroke patients at Inpatient Rehabilitation Facilities (IRF). Aim: To examine trends in functional outcomes...
Dispersion of surface-modified, aggregated, fumed silica in polymer nanocomposites

Surface modification of model silica to enhance compatibility in nanocomposites has been widely studied. In addition to model spherical silica, several authors have investigated the impact of surface conditions on compatibility in commercial aggregated carbon black and silica. In this paper, dispersion is investigated for a series of nanocomposites produced from commercially modified fumed silica mixed with styrene butadiene rubber, polystyrene, and polydimethylsiloxane. Surface modification includes variation in surface hydroxyl content, siloxane, and silane treatment. Qualitatively, hydroxyl groups on the silica surface are considered incompatible with non-polar polymers, while methyl groups are compatible with oleophilic polymers. X-ray scattering was used to analyze the filler aggregate structure before and after dispersion, and the second virial coefficient was used to quantify nanodispersion. The content of surface moieties was determined from Fourier-transform infrared spectroscopy. It is observed that modified silica can display mean field or specific interactions as reflected by the presence of a correlation peak in x-ray scattering. For systems with specific interactions, a critical ordering concentration is observed related to the free energy change for structuring. A van der Waals model was used to model the second virial coefficient as a function of accumulated strain, yielding the excluded volume and an energetic term. The excluded volume could be predicted from the structural information, and the bound polymer layer was directly related to the surface methyl content, whereas the energetic term was found to synergistically depend on both the methyl and hydroxyl surface content.
Predicting implant size in total knee arthroplasty using demographic variables

Aims The purpose of this investigation was to determine the relationship between height, weight, and sex with implant size in total knee arthroplasty (TKA) using a multivariate linear regression mo...
Patterns in Radon Activity in California Groundwater

Naturally occurring radon-222 (222Rn) is an effective marker of groundwater inflow to streams, lakes, and coastal environments. However, 222Rn activity in groundwater is difficult to predict, and e...
Understanding Sponsored Search: Modeling the Process of Sponsored Search

This is an opening shot of changing the search engines from white pages to yellow pages. Bill Gross, 1998 as quoted in: Sullivan, D., The Search Engine Report . In our framing shop example of setting up our sponsored-search account, we touched on a process by example without a real appreciation for the underlying complexity of the technology and human interaction inherent in sponsored search. What is the technology that makes the whole process work? What is the business model of sponsored search? Who are the major actors in sponsored search? What are the goals and motivations of these actors? For answers to these and other questions, we examine the sponsored-search model.
Time to discontinuation of atypical versus typical antipsychotics in the naturalistic treatment of schizophrenia.

There is an ongoing debate over whether atypical antipsychotics are more effective than typical antipsychotics in the treatment of schizophrenia. This naturalistic study compares atypical and typical antipsychotics on time to all-cause medication discontinuation, a recognized index of medication effectiveness in the treatment of schizophrenia. We used data from a large, 3-year, observational, non-randomized, multisite study of schizophrenia, conducted in the U.S. between 7/1997 and 9/2003. Patients who were initiated on oral atypical antipsychotics (clozapine, olanzapine, risperidone, quetiapine, or ziprasidone) or oral typical antipsychotics (low, medium, or high potency) were compared on time to all-cause medication discontinuation for 1 year following initiation. Treatment group comparisons were based on treatment episodes using 3 statistical approaches (Kaplan-Meier survival analysis, Cox Proportional Hazards regression model, and propensity score-adjusted bootstrap resampling methods). To further assess the robustness of the findings, sensitivity analyses were performed, including the use of (a) only 1 medication episode for each patient, the one with which the patient was treated first, and (b) all medication episodes, including those simultaneously initiated on more than 1 antipsychotic. Mean time to all-cause medication discontinuation was longer on atypical (N = 1132, 256.3 days) compared to typical antipsychotics (N = 534, 197.2 days; p < .01), and longer on atypicals compared to typicals of high potency (N = 320, 187.5 days; p < .01), medium potency (N = 140, 213.5 days; p < .01), and low potency (N = 74, 208.7 days; p < .01). Among the atypicals, only clozapine, olanzapine, and risperidone had significantly longer time to all-cause medication discontinuation compared to typicals, regardless of potency level, and compared to haloperidol with prophylactic anticholinergic treatment. When compared to perphenazine, a medium-potency typical antipsychotic, only clozapine and olanzapine had a consistently and significantly longer time to all-cause medication discontinuation. Results were confirmed by sensitivity analyses. In the usual care of schizophrenia patients, time to medication discontinuation for any cause appears significantly longer for atypical than typical antipsychotics regardless of the typical antipsychotic potency level. Findings were primarily driven by clozapine and olanzapine, and to a lesser extent by risperidone. Furthermore, only clozapine and olanzapine therapy showed consistently and significantly longer treatment duration compared to perphenazine, a medium-potency typical antipsychotic.
“I keep collecting: college students build and utilize collections in spite of breakdowns

As people become more and more involved with digital information, they grow proportionally involved in situated practices of collecting. They put together large sets of information elements. However, their attention to those information elements is limited. They use whatever means are at hand in order to form representations of their collections. They need to keep track of the elements in these collections, so they can use them later. We conducted a study with 20 college students. A major concern for the students during collection building was collection management and utilization, particularly as the size and number of their collections grows. They experienced breakdowns in these processes, yet continued to engage in collecting. They developed strategies such as informal metadata schemas and hierarchical organization to try to cope with their problems. We consider the practices observed, and their implications for the development of tools to support digital collection building and utilization. Collection representations that support cognition, collaboration, and semantic schemas are prescribed.
Multipolar or Multilateral? Diffusion of Power, the BRICS, and the United States

Multipolar or Multilateral? Diffusion of Power, the BRICS, and the United States In an increasingly globalized world, power has become more diffused. Brazil Russia, India China, and South Africa (the BRICS) and many others have emerged as significant actors. The appearance of these and other rising powers is not entirely new, but together they represent an increasing presence in economic, cultural, political and even security terms. At the same time, the relative weight of Europe and Japan has seemed to ebb as these traditional centers of power have experienced economic and demographic stagnation. Political and scholarly observers have tended to greet these changes by heralding a new era in which the BRICS would not only become far more influential in world affairs, but would act to reshape, sustain and promote international institutions and regimes in an increasingly multipolar world. But are these assumptions accurate? Are the BRICS increasingly acting as stakeholders, or is the international order becoming more multipolar without becoming more multilateral? In practice, across a wide range of issue areas the BRICS have often been less rather than more cooperative in sustaining international institutions and international order. In these circumstances, the role of the United States requires particular attention. I have previously argued that the international engagement of the United States was not only essential for reasons of national interest, but that it was vital for sustaining global order. More recently, I addressed the puzzle of whether the U.S. still possesses the capacity to play that critical role. My tentative answer was that the material underpinnings for such a role remain viable and even robust, but that the determinants are as much ideational, in terms of policy, leadership, and political will, as they are material. With these considerations in mind, I now seek to address the interplay between the role of the United States and that of the BRICS. The question of decline is of critical importance, not only in terms of national interest, but also because the United States has played a unique role as the world’s principal provider of public goods. This role has included creating and sustaining international institutions, supporting regional stability, security and nonproliferation, underpinning the global economy, and encouraging human rights and democratization. Consequently, a combination of American retrenchment and BRIC abdication would be likely to see a weakening not only of multilateral institutions but of these elements of international order.
Nitrogen fixation in a desert stream ecosystem

Few measurements of nitrogen fixation exist for streams. Desertstreams are warm, well lighted, and often supportabundant cyanobacterial populations; thus N2 fixationmay be significant in these N-poor ecosystems. N2fixation was measured in situ by acetylene reductionfor two patch types (Anabaena mat and anepilithic assemblage). Patch-specific rates were highcompared with published values (maximum 775 µgN2 [83 µmol C2H4]mg chl a -1 h-1or 51 mg N2 [5.4 mmol C2H4] m-2 h-1).Daytime fixation was higher than nighttimefixation, and temperature, light and inorganic Nconcentration explained 52% of variance in hourlyrates over all dates. Diel input-output budgets wereconstructed on five dates when cyanobacteria werepresent in the stream. Diel N2 fixation rates weremeasured for comparison with reach-scale diel nitrogenretention, to assess the importance of this vector to Neconomy of the stream. Fixation accounted for up to85% of net N flux to the benthos, but its importancevaried seasonally. Finally, we applied biomass-specificfixation rates to 1992 and 1993 biomass data to obtainseasonal and annual N2 fixation estimates.Cyanobacteria were absent or rare during winter andspring, thus most of the annual N2 fixation occurredduring summer and autumn. Annual rates of nitrogenfixation for 1992 and 1993 (8.0 g/m2 and 12.5g/m2) were very high compared to other streams,and moderately high compared to other ecosystems.Like other phenomena in this disturbance-proneecosystem, nitrogen fixation is strongly influenced bythe number and temporal distribution of flood events.
Clinical anatomy of the G-spot

The existence of the G-Spot has never been unequivocally confirmed. With increased public exposure and a trend towards sexual gratification, however, the impetus to elucidate this structure is greater than ever. This review will focus on research that has been conducted on the clinical anatomy of the G-Spot. Ultimately this review will show that while the distal area of the anterior vaginal wall appears to be the most sensitive region of the vagina, the existence of an anatomical "G-spot" remains to be demonstrated.
Dosage Suppressors of a Benomyl-Dependent Tubulin Mutant: Evidence for a Link between Microtubule Stability and Cellular Metabolism

To identify factors important for the regulation of microtubule stability in yeast, dosage suppressors of the hyperstable microtubule phenotype of the budding yeast tub2-150 beta-tubulin mutation were isolated. Of the two suppressors reported here, one (JSN2) encodes a tRNAVal, and the other (JSN3) is an antimorphic allele of the methionine biosynthesis transcription factor Met4p. Furthermore, growth of tub2-150 mutants and suppression of tub2-150 mutants by JSN3 are sensitive to levels of methionine in the growth medium. We explore several possible explanations for these findings, including the potential involvement of the general amino acid control and the involvement of Cbflp, a component of yeast kinetochores that is also necessary for Met4p-mediated transcription.
Agrobacterium -mediated transformation of the medicinal plant Centaurea montana

An efficient transformation system was developed for Centaurea montana by co-cultivation of leaf explants with Agrobacterium tumefaciens strain AGL1 that contained a plasmid harboring the isopentenyl transferase gene under the control of the developmentally regulated Atmyb32 promoter of Arabidopsis thaliana and the gene encoding for hygromycin resistance under the control of the Cauliflower Mosaic Virus 35S (CaMV35S) promoter. A total of 990 explants were infected with Agrobacterium, and 18 shoots were regenerated resulting in an overall transformation efficiency of 1.8%. Molecular analyses, including PCR, Southern blotting and RT-PCR, were performed on T0 and T1 plants to confirm chromosomal integration and expression of the transgene in the phenotypically normal transformed plants. Transformation of C. montana was also performed using A. tumefaciens supervirulent strain EHA105 harboring the β-glucuronidase (GUS) reporter gene. Expression of the GUS gene in the putative transgenics was confirmed using a histochemical GUS assay.
A non-isothermal technique using thermal optical analysis to follow the kinetics of polymer crystallization and solid state phase transformation and the determination of the length of the crystalline segment☆

Abstract A non-isothermal technique was developed to study the kinetics of solid transformations using thermal optical analysis (TOA). Similar to the methods using TGA and TXA were previously reported, an expression was derived that utilizes integral and differential curves. TOA involves the measurement of transmitted light intensities of a material examined between cross polars and does not require a weight change or an extractable crystalline peak. For quantitative data, it is necessary to have instrumentation in which the photometer optics and temperature state are integrated to optimize the light intensities and to record them quantitatively. In addition, circular polarized light was used to eliminate sample orientation. In order to confirm its applicability and for comparison, the technique was applied to the low density crosslinked polyethylene polymer previously studied using TGA and TXA. The enthalpy for the transformation was found to be 13.2 kcal/equiv. which was in agreement with TXA results. TOA also showed, however, a second transformation at higher temperatures and low % crystallinities, with a 67.2 kcal/equiv. enthalpy.
Failure to Demonstrate Antibody in Feces of Monkeys Vaccinated with Poliomyelitis Virus, Lansing Strain.∗†:

Summary and ConclusionFour monkeys were vaccinated with active preparations of the Lansing strain of poliomyelitis virus by parenteral routes. One animal received a total inoculum of 1.4 g of infected tissue, at the time of intracerebral challenge had an antibody titer in the serum of 800 against 10 LD50 of virus, but succumbed to an acute poliomyelitic infection. The remaining 3 received 2.4 g of inoculum, had antibody titers in their sera of approximately 2000 against 10 LD50 of virus and did not develop the disease. Each of 2 additional inoculations resulted in an increase in antibody of the serum to levels of 5100 and 8300 against 10 LD50 of virus. Despite the fact that Lansing virus antibody in the serum of three monkeys reached high titers, no evidence was obtained for the presence of antibody in the feces. Antibody was not detected in single specimens in the feces obtained from 6 humans whose sera had moderate titers of antibody to the Lansing strain of poliomyelitis virus. It is concluded on the b...
Special Student contest on a Collective Intelligence Challenge Problem

Students and observers are cordially invited to join a Student Special Session on Thursday afternoon concerning a “Collective Intelligence Challenge Problem” (snacks and coffee provided.) From Wikipedia, “Collective intelligence is a shared or group intelligence that emerges from the collaboration and competition of many individuals.” Sign up at the registration desk beginning on Tuesday for speaking time slots (5 minutes) and the option to present two power point slides in a speed session focused on using collective intelligence to understand possible research areas for collaborative control system engineering. For instance, come give us your thoughts on how we can better organize and disseminate controls knowledge, control algorithm objects, and control system building blocks within the open cyber world? How do we solve the problem that control system engineers within industry are overwhelmed by the amount of controls related information available through cyber discovery, as even a simple search on “control system” gives over 1 billion hits! As control system engineers, how should we organize the knowledge within our area of engineering to facilitate expedient development of control systems in an increasingly systems-of-systems world? Please feel free to share this invitation with your colleagues.
Adapting binary fitness functions in Genetic Algorithms

Recent applications of Genetic Algorithms (GAs) in the search for specimens of interesting discrete mathematical objects have suggested that GA convergence time can be improved by adapting fitness function components on the fly. In particular, it is known that if such fitness functions F have the form F = Σk Fi where {Fi} is a set of fitness functions associated with properties {Pi} that collectively define the search problem, then we can improve GA performance by defining a related fitness function F' as follows: if each Fi can be normalized so that c is a solution if and only if Fi(c) = 1, then we can introduce coefficients {αi}, where αi > 0 and Σk αi = 1, and then define F' = Σk αiFi. With this definition, c is a solution for F if and only if c is a solution for F'. Furthermore, convergence of the GA for F' can be improved by modifying the coefficients {αi} dynamically throughout the GA run. In this paper we show that similar improvements in convergence times can also be obtained for a broad category of GA search problems whose fitness functions are defined on binary strings of fixed length.
Nonaqueous Liquid/Liquid Interfaces: Surface Activity at the Interface betweenn-Paraffins andN-Alkyl Derivatives of 2-Pyrrolidone

Abstract While nonaqueous liquids are widely used commercially, the interfacial chemistry of nonaqueous liquid/liquid systems has received scant attention. In this paper interfacial properties of partially miscible two-component systems ofn-hexadecane with 2-pyrrolidone,N-methyl-2-pyrrolidone orN-ethyl-2-pyrrolidone, and ofn-heptane withN-methyl-2-pyrrolidone at 25°C are presented. The surface activity of the long-chainN-alkyl-2-pyrrolidones at these interfaces was also studied. The adsorption of the long-chain pyrrolidones increases with chain length following a modified form of Traube's rule. Partition coefficients for the long-chain pyrrolidones at low concentrations were measured, and standard free energies of transfer between the coexisting bulk phases and between each bulk phase and the interface were calculated. At higher concentrations, the interfacial tensions of the longer chain pyrrolidones go toward zero as the systems become more miscible. The temperature variation of the hexadecane/N-methyl-2-pyrrolidone and the hexadecane/N-ethyl-2-pyrrolidone interfacial tensions were also measured.
Interaction of surface magnetoplasmons and surface optical phonons in polar semiconductors

Abstract A theoretical investigation has been carried out of surface polaritons associated with surface magnetoplasmons coupled to surface optical phonons in polar semiconductors. The coupled mode frequencies are calculated for several orientations of the magnetic field relative to the surface and the direction of propagation in the large wave vector (unretarded) limit. Dispersion curves are calculated for the configuration in which the magnetic field is parallel to the surface and is perpendicular to the wave vector. Experimental possibilities for observing the interaction effects are discussed.
The Incomplete Picture of Incomplete Spinal Cord Injury

Traumatic spinal cord injury (SCI) is a devastating and debilitating condition that largely affects young adults in the prime of their lives. There are roughly 12,000 cases of spinal cord injuries each year, and over 250,000 people with traumatic spinal cord injury are living in the USA [1]. Increasing life expectancy of spinal cord injured patients has lead to an increased worldwide prevalence of SCI, which is now approaching two million, and now approximately $4 billion dollars are spent annually in the acute treatment and chronic care of spinal cord-injured individuals [1]. Despite the immense impact of SCI at a personal and societal level, treatment aimed at attenuating the initial degree of neurologic injury and reducing patients’ future dependency are lacking, particularly in comparison to the resources that have been directed toward the management of head injury. Currently, no study has conclusively demonstrated the effectiveness of early spinal cord decompression, neurocritical care strategies for augmenting spinal cord perfusion are supported by class III evidence, and there are currently no neuroprotectants generally accepted for use in spinal cord injury.
t-Matrix calculation of ground state energy of solid He3

Abstract The results of recent extensive numerical computations of the ground state energy of solid He 3 in the t -matrix framework are summarized and compared with previous results. The improvements brought about by the exact numerical evaluation are emphasized.