cssi/SciSciGPT-SciSciNet huggingface dataset:
The Effect of Incarceration on Mortality

This paper analyzes the effect of incarceration on mortality using administrative data from Ohio between 1992 and 2017. Using event study and difference-in-differences approaches, we compare mortality risk across incarcerated and non-incarcerated individuals before and after pre-scheduled releases from prison. Mortality risk halves during the period of incarceration, with large declines in murders, overdoses, and natural causes of death. However, there is no detectable effect on post-release mortality risk, meaning that incarceration increases longevity. These estimates reflect the high-risk environment faced by criminal justice-involved individuals when not incarcerated and suggest other potential policies that could reduce these risks.
Lossless Monochromation for Electron Microscopy with Pulsed Photoemission Sources and Radio-Frequency Cavities

Resonant radio-frequency cavities enable exquisite time-energy control of electron beams when synchronized with laser-driven photoemission. We present a lossless monochromator design that exploits this fine control in the one-electron-per-pulse regime. The theoretically achievable maximum beam current on target is orders of magnitude greater than state-of-the-art monochromators for the same space-time-energy resolution. This improvement is the result of monochromating in the time domain, unconstrained by the transverse brightness of the electron source. We show analytically and confirm numerically that cavity parameters chosen to minimize energy spread perform the additional function of undoing the appreciable effect of chromatic aberration in the upstream optics. We argue that our design has significant applications in ultrafast microscopy, as well as potential for use in nontime resolved microscopy, provided future photoelectron sources of sufficiently small size and laser sources of sufficiently high repetition rate. Our design achieves in simulations more than two orders of magnitude reduction in beam energy spread, down to single digit milli-electron volts. Overcoming the minimum probe-size limit that chromatic aberration imposes, our design clears a path for high-current, high-resolution electron-beam applications at primary energies from single to hundreds of kilo-electron volts.
Evaluation of Old and Historic Buildings Subjected to Fire

Abstract Buildings with historic and cultural significance are part of the national heritage and must be preserved for future generations. Preservation of historic buildings depends upon usage cons...
Prognostic accuracy of sirs, qsofa, and news scoring for in-hospital mortality among patients with COVID-19

INTRODUCTION The clinical course of Coronavirus 19 disease (COVID-19) remains unpredictable. In the setting of pandemic disease, investigations such as arterial blood gases are difficult to obtain on admission. This retrospective study evaluated the ability of the systemic inflammatory response syndrome (SIRS), quick sequential organ failure assessment (qSOFA), and national early warning signs (NEWS) scores to predict in-hospital mortality. These scoring systems require limited data and may offer utility with regard to predicting outcomes on admission. METHODS Demographic, clinical, and outcome data were analyzed in 520 patients admitted for COVID-19 between March 20, 2020 and May 5, 2020. SIRS, qSOFA, and NEWS scoring was applied to each patient based on their admission characteristics. Receiver Operator Curve (ROC) analyses were completed to assess the predictive accuracy for in-hospital mortality. The need for ICU level of care was evaluated as a secondary composite outcome. Univariate regression analyses were completed to assess the predictive function of each scoring threshold. RESULTS Of 520 patients enrolled, 57.5% were male. Of the cohort, 53.8% were Hispanic, 33.3% were African American, 5.8% were Asian, and 7.3% were Caucasian. Mean age was 61.6 years of age. A total of 182 patients (35%) died in hospital. 179 patients (34.4%) required ICU level of care. NEWS demonstrated the greatest discrimination for in-hospital mortality (AUC 0.716 [95% CI, 0.671-0.762]) and ICU admission (AUC 0.641 [95% CI, 0.591-0.691]). The predictive ability of SIRS criteria was more modest for in-hospital mortality (AUC 0.611 [95% CI, 0.560-0.662]) and ICU admission (AUC 0.571 [95% CI, 0.520-0.622]). qSOFA demonstrated the least discrimination for in-hospital mortality (AUC 0.534 [95% CI, 0.479-0.588]) and ICU admission (AUC 0.545 [95% CI, 0.491-0.599]). A mortality rate of 59.76% was observed in patients with a NEWS score ≥ 5 (OR 3.354 [95% CI, 2.213-5.083]). Likewise, a mortality rate of 56.48% was observed in patients with a SIRS score ≥ 2 (OR 1.77 [95% CI, 1.21-2.59]), while a mortality rate of 30.33% was observed in patients with a qSOFA score ≥ 2 (OR 2.124 [95% CI, 1.442-3.129]). CONCLUSION Our findings suggest NEWS offers the best prognostic accuracy in predicting in-hospital mortality, as compared to qSOFA and SIRS scoring systems. (Table Presented).
Transport properties and thermal behavior of YbMnSb2 semimetal above room temperature

Abstract Single crystals of ytterbium manganese diantimonide, YbMnSb2 have been grown from a high-temperature reaction of the elements, employing molten Sb as self-flux. This phase crystallizes in the tetragonal centrosymmetric space group P4/nmm (No. 129) and adopts the ZrCuSiAs structure type. The structure consists of Sb-based square nets and PbO-type layers formed by fused [MnSb4/4] tetrahedra. YbMnSb2 is stable under ambient atmosphere and incongruently melts at a temperature of ca. 1120 K. In the temperature range from 300 ​K to 450 ​K, the electrical resistivity of the as-grown single-crystalline material is as low as 3.2 ​mΩ ​cm, while its thermopower is as high as 180 ​μV/K. As such, YbMnSb2 shows promise for thermoelectric applications in the mid-temperature region, with an estimated power factor of 0.85–0.95 mW/(m K2).
Bandit Algorithms for Precision Medicine

The Oxford English Dictionary defines precision medicine as "medical care designed to optimize efficiency or therapeutic benefit for particular groups of patients, especially by using genetic or molecular profiling." It is not an entirely new idea: physicians from ancient times have recognized that medical treatment needs to consider individual variations in patient characteristics. However, the modern precision medicine movement has been enabled by a confluence of events: scientific advances in fields such as genetics and pharmacology, technological advances in mobile devices and wearable sensors, and methodological advances in computing and data sciences. This chapter is about bandit algorithms: an area of data science of special relevance to precision medicine. With their roots in the seminal work of Bellman, Robbins, Lai and others, bandit algorithms have come to occupy a central place in modern data science ( Lattimore and Szepesvari, 2020). Bandit algorithms can be used in any situation where treatment decisions need to be made to optimize some health outcome. Since precision medicine focuses on the use of patient characteristics to guide treatment, contextual bandit algorithms are especially useful since they are designed to take such information into account. The role of bandit algorithms in areas of precision medicine such as mobile health and digital phenotyping has been reviewed before (Tewari and Murphy, 2017; Rabbi et al., 2019). Since these reviews were published, bandit algorithms have continued to find uses in mobile health and several new topics have emerged in the research on bandit algorithms. This chapter is written for quantitative researchers in fields such as statistics, machine learning, and operations research who might be interested in knowing more about the algorithmic and mathematical details of bandit algorithms that have been used in mobile health.
Investigating the Relationship Between a Driver's Psychological Feelings and Biosensor Data.

Recent studies show that emotional changes can influence driving behavior. For example, positive valence could enable better takeover performance in regaining vehicle control. On the other hand, a state of anger has been shown to degrade driver situational awareness and performance compared to a neutral state. These emotional states may result from different factors like a vehicle’s internal or external environment. The roadside environment is one of the external factors which might influence driver behavior and performance. Hence, it is necessary to understand how emotional conditions affect driving actions to design safer road environments. However, research involving the use of emotions can be challenging due to methodological issues associated with measuring emotions. Different methods can be used to measure emotion both subjectively and objectively. These could include the use of reliable sources for assessing evoked emotions, since subjective emotional experiences are the essence of a feeling. An objective manifestation of emotion can be captured as a representation of our inner experience. Also, the objective manifestation of emotion is the representation of our inner experience. In this study, we conducted an eye-integrated human-in- the- loop (HTIL) simulation experiment to analyze the driver’s emotional state by comparing both subjective and objective data to find the relation between drivers’ physiologic feelings (i.e., Kansei Engineering method) and biosensor data (i.e., facial expression and eye movement).
Photophysical and photochemical properties of fullerenes

On irradiation with visible and UV light, fullerenes C60 and C70 give high yields of their triplet states. Fluorescence is very weak from both, and phosphorescence has been observed only from C70. The triplet states are also formed efficiently by energy transfer from triplet sensitizers with energies above 35 kcal/mol. Triplet fullerenes transfer energy efficiently to oxygen, giving singlet molecular oxygen, but they react and quench singlet oxygen very inefficiently, making them excellent photosensitizers. The fullerenes C60 and C70 are easily reduced but very difficult to oxidize. Electron transfer to triplet C60 and C70 occurs readily from electron donors to produce the radical anions. C60 can also be oxidized by excited high-potential photosensitizers to the radical cation. Some dihydrofullerenes also give high yields of the triplet state and singlet oxygen on irradiation. Photoreaction of C60 with electron-rich compounds appears to be an efficient route to difunctionalized adducts.
Wittgenstein's Diagonal Argument: A Variation on Cantor and Turing

On 30 July 1947 Wittgenstein penned a series of remarks that have become well-known to those interested in his writings on mathematics. It begins with the remark “Turings ‘machines’: these machines are humans who calculate. And one might express what he says also in the form of games”. Though most of the extant literature interprets the remark as a criticism of Turing’s philosophy of mind (that is, a criticism of forms of computationalist or functionalist behaviorism, reductionism and/or mechanism often associated with Turing), its content applies directly to the foundations of mathematics. For immediately after mentioning Turing, Wittgenstein frames what he calls a “variant” of Cantor’s diagonal proof. We present and assess Wittgenstein’s variant, contending that it forms a distinctive form of proof, and an elaboration rather than a rejection of Turing or Cantor.
Tracing Analytic Ray Curves for Light and Sound Propagation in Non-Linear Media

The physical world consists of spatially varying media, such as the atmosphere and the ocean, in which light and sound propagates along non-linear trajectories. This presents a challenge to existing ray-tracing based methods, which are widely adopted to simulate propagation due to their efficiency and flexibility, but assume linear rays. We present a novel algorithm that traces analytic ray curves computed from local media gradients, and utilizes the closed-form solutions of both the intersections of the ray curves with planar surfaces, and the travel distance. By constructing an adaptive unstructured mesh, our algorithm is able to model general media profiles that vary in three dimensions with complex boundaries consisting of terrains and other scene objects such as buildings. Our analytic ray curve tracer with the adaptive mesh improves the efficiency considerably over prior methods. We highlight the algorithm’s application on simulation of visual and sound propagation in outdoor scenes.
Evangelists of culture: One Book programs and the agents who define literature, shape tastes, and reproduce regionalism

Abstract The evangelists of culture are mid-level professionals who engage directly with the public. Sociological theories of cultural authority or popular demand fail to explain decisions made at this juncture. An analysis of 3110 selections made by 567 One Book programs, together with interviews with One Book program leaders from all 50 states, reveals that while those people working on the front line of culture both share the literary tastes of cultural authorities and recognize contemporary reader preferences, their choices do not reflect either. Instead, their selections are creative, the product of institutional needs, professional agendas, and a persistent tropism toward regional authors and themes. One Book programs perpetuate a culture of place – literary regionalism – that resists both elite tastes and market forces.
Impulse Gauss curvatures: 2002 SSHE-MA conference

In Riemannian (differential) geometry, the differences between Euclidean geometry, elliptic geometry, and hyperbolic geometry are understood in terms of curvature. I think Gauss and Riemann captured the essence of geometry in their studies of surfaces and manifolds, and their point of view is spectacularly illuminating. Unfortunately, curvature is highly non-trivial to work with. I will talk about a more accessible version of curvature that dates back to Descartes.
A study of positive energy condition in Bianchi V spacetimes via Noether symmetries

In this paper we use Noether symmetries of the geodesic Lagrangian in Bianchi V spacetimes to study various cosmological solutions of Einstein’s field equations. Our first result is the identification of the subalgebras of Noether symmetries of the equations of motion in such spacetimes with dimension 4, 5, 6, 7, 9 or 10 of the maximal algebra of Lie point symmetries of dimension 13. Second, we give a physical interpretation of new cosmological solutions which satisfy the positive energy condition and yield critical bounds on the expansion coefficient $$\alpha $$ , in which the underlying non-flat spacetimes have interesting physical properties. Specifically the energy density behaves in one of the following ways. (i) It is positive and constant for all time. (ii) It varies with time and attains a global maximum after some time and then asymptotically converges to zero. (iii) It increases for all time and attains a maximum value at the asymptotic limit $$t\rightarrow \infty $$ . In particular a non-flat spacetime is obtained that mimics the expansion in a flat FRW universe dominated by vacuum energy such that the expansion factor has the same form in both. However, the energy density is dynamical in the former.
Synthesis of Heterocycles from Hydrogen Cyanide Derivatives

Publisher Summary Hydrogen cyanide has been used to synthesize heterocyclic compounds almost as long as organic chemistry has existed as a branch of the science. This chapter focuses on heterocyclic synthesis wherein most of the ring atoms and the substituent groups are derived from HCN. It discusses hydrogen cyanide oligomers: HCN dimer, HCN trimer, HCN tetramers, and HCN pentamers. The chapter emphasizes on diaminomaleonitrile (DAMN) and its oxidation product diiminosuccinonitrile (DISN). DAMN is produced on an industrial scale by sodium cyanide catalyzed tetramerization of HCN in a polar solvent such as dimethylformamide. DISN, an oxidation product of DAMN, can also be made by addition of 2 mol HCN to cyanogens. Photolysis of DAMN over a relatively long period of time produces 4-amino-5-cyanoimidazole. 4-Amino-5-cyanoimidazole can also be obtained nonphotochemically. This chapter discusses synthesis of 4-Amino-5-cyanoimidazole which is used for conversion to purines.
Optimizing Display Advertising Markets: Challenges and Directions

Display advertising is the major source of revenue for service and content providers on the Internet. Here, the authors explain the prevalent mechanisms for selling display advertising, including reservation contracts and real-time bidding. Discussing some of the important challenges in this market from optimization and economic perspectives, they also survey recent results and directions for future research.
Exemplar or matching: modeling DCJ problems with unequal content genome data

The edit distance under the DCJ model can be computed in linear time for genomes with equal content or with Indels. But it becomes NP-Hard in the presence of duplications, a problem largely unsolved especially when Indels (i.e., insertions and deletions) are considered. In this paper, we compare two mainstream methods to deal with duplications and associate them with Indels: one by deletion, namely DCJ-Indel-Exemplar distance; versus the other by gene matching, namely DCJ-Indel-Matching distance. We design branch-and-bound algorithms with set of optimization methods to compute exact distances for both. Furthermore, median problems are discussed in alignment with both of these distance methods, which are to find a median genome that minimizes distances between itself and three given genomes. Lin---Kernighan heuristic is leveraged and powered up by sub-graph decomposition and search space reduction technologies to handle median computation. A wide range of experiments are conducted on synthetic data sets and real data sets to exhibit pros and cons of these two distance metrics per se, as well as putting them in the median computation scenario.
A monkey metabolism pod for space flight weightlessness studies.

An experiment system is described which will permit quantitative physiological studies in 8–14 kg adult monkeys during future space flight opportunities such as the NASA Shuttle. The system comprises a fiberglass pod containing a comfortable restraint couch for the animal. The pod is divided into upper and lower halves. When the monkey occupies the couch, a rubber belly-band forms a gas seal between the upper and lower portions of the animal. The upper-pod ventilating air stream is monitored for Po2, Pco2, Pn2 and Ph2o to permit continuous metabolic gas-exchange measurements for computation of metabolic energy expenditure. The lower pod is lined with ashless filter paper for excreta collection and entrapment of liquid urine, and is ventilated separately. At the end of experimental periods of 1 to 7 days, all excreta plus the filter paper are removed for chemical analysis. The lower-pod ventilating gas ports also allow application of lower-body negative pressure to test cardiovascular competency when desired. The upper pod is provided with automatic food pellet and drinking water dispensers for quantitative measurement of nutrient intake. Balance assessment of the following elements can be made: N, Ca, P, Mg, K, Na, Cl, S and Fe. Animals have been kept in continuous restraint in the system for as long as 30 days without apparent ill effects.
Radiation risks to lymphoma patients undergoing 18F-FDG studies

e22024 Background: To investigate radiation risks to patients undergoing 18F-FDG studies that take into account patient age, sex, and weight. Methods: We obtained patient demographics and weights of 54 consecutive patients with lymphoma who each underwent a18F-FDG PET study. The administered activity was converted into an effective dose using the patient size dependent dosimetry data provided in ICRP Publication 80. Patient effective doses were converted into estimates of the lifetime attributable risk of cancer incidence and cancer mortality using age and sex dependent risk factors provided in BEIR VII. Results: The average patient age/weight in this study was 43 years/68 kg for males and 33 years/61 kg for females. Patient effective dose are proportional to patient weight(-0.784) (r2 >0.99). The average administered activity was 410 MBq, which resulted in an average effective dose of 8.5 mSv for males and 8.9 mSv for females. The average cancer incidence was 0.71/1,000 cases for males, and 1.27/1,000 ca...
A simulation study of multimicrocomputer networks

Recent developments in integrated circuit technology have suggested a new building block for parallel processing system::;: the single chip computer. This building block makes iL economically feaSible to interconnect large numbers of computers to ferm a muttiImcrocomputer network. Becat:.se the nodes of .men a network do not share any memory, it is Cl'llclUl that a inlerr,unneclion network capable of efficiently supporting message passing be found. We prp.sent a model of Lime varying computation based on task precedence graphs that corresponds closely to the beilav1rIl' of fork/join algorithms such as divide ~nd conquer. Using thIS mond, we investigate the behavior f)f t:!ve interconncctiol~ ndwod~s under varying "Workloads with distributed scheduling.
PRODUCER ACCEPTANCE OF A NEW PEANUT MARKETING COOPERATIVE: A SURVEY OF GEORGIA PEANUT PRODUCERS

Market conduct has become an important issue for peanut farmers. Consolidation in the first buyer market, increased imports, and political uncertainty have increased peanut producers' marketing risks. The purpose of this paper was to examine demographic differences in peanut producers' perceptions of the current marketing environment as well as their attitudes towards new marketing institutions. A standard t-test revealed that producers growing more than 250 acres of peanuts, irrigating at least 50 percent of their peanuts, and producers located in Southwest Georgia were statistically more dissatisfied with the current marketing environment and significantly more receptive to forming a new generation peanut cooperative.
Multimodal facial gender and ethnicity identification

Human faces provide demographic information, such as gender and ethnicity. Different modalities of human faces, e.g., range and intensity, provide different cues for gender and ethnicity identifications. In this paper we exploit the range information of human faces for ethnicity identification using a support vector machine. An integration scheme is also proposed for ethnicity and gender identifications by combining the registered range and intensity images. The experiments are conducted on a database containing 1240 facial scans of 376 subjects. It is demonstrated that the range modality provides competitive discriminative power on ethnicity and gender identifications to the intensity modality. For both gender and ethnicity identifications, the proposed integration scheme outperforms each individual modality.
Person and Vehicle Tracking in Surveillance Video

This evaluation for person and vehicle tracking in surveillance presented some new challenges. The dataset was large and very high-quality, but with difficult scene properties involving illumination changes, unusual lighting conditions, and complicated occlusion of objects. Since this is a well-researched scenario [1], our submission was based primarily on our existing projects for automated object detection and tracking in surveillance. We also added several new features that are practical improvements for handling the difficulties of this dataset.
Designing scalable WDM optical interconnects using predefined wavelength conversion

This paper investigates the problem of designing scalable and cost-effective wavelength division multiplexing (WDM) optical interconnects. We propose a new design for WDM optical interconnect that has several advantages over existing designs. First, wavelength conversion occurs between two predefined wavelengths. This not only eliminates the need for expensive wide-range wavelength converters, but also ensures high scalability as the conversion range is independent of the number of the wavelengths in the system. Second, the new design requires a smaller number of switching elements compared to most of the recent best interconnect designs.
Quantum Criticality in a Clean Metal

Classical phase transitions, which are driven by thermal vibrations, follow the concept of "universality": No matter how complex the system, its behavior near the phase transition should be largely governed by its spatial dimensionality. Quantum phase transitions are much more difficult to study. In their Perspective, [Aeppli and Soh][1] highlight the report by [ Grigera et al .][2], who have succeeded in characterizing the quantum phase behavior of an unusually clean metal system. This and other studies are indicating that quantum phase transitions also follow a universal behavior. [1]: http://www.sciencemag.org/cgi/content/full/294/5541/315 [2]: http://www.sciencemag.org/cgi/content/short/294/5541/329
Experimental Results on Statistical Approaches to Page Replacement Policies

This paper investigates the questions of what statistical information about a memory request sequence is useful to have in making page replacement decisions. Our starting point is the Markov Request Model for page request sequences. Although the utility of modeling page request sequences by the Markov model has been recently put into doubt ([13]), we find that two previously suggested algorithms (Maximum Hitting Time [11] and Dominating Distribution [14]) which are based on the Markov model work well on the trace data used in this study. Interestingly, both of these algorithms perform equally well despite the fact that the theoretical results for these two algorithms differ dramatically. We then develop succinct characteristics of memory access patterns in an attempt to approximate the simpler of the two algorithms. Finally, we investigate how to collect these characteristics in an online manner in order to have a purely online algorithm.
The rank join problem

In the rank join problem, we are given a set of relations and a scoring function, and the goal is to return the K join results with the highest scores. It is often the case in practice that the inputs may be accessed in ranked order and the scoring function is monotonic. These conditions allow for efficient algorithms that solve the rank join problem without reading all of the input. In this chapter, we review recent efforts in the development and analysis of such rank join algorithms. First, we present some theoretical results that state the inherent complexity of the rank join problem and essentially reveal that any rank join algorithm has to trade off between I/O efficiency and computational efficiency. We then review a specific rank join algorithm that adjusts this trade-off at runtime, depending on the data and the scoring function, in order to strike a balance between I/O overhead and computation.
Macrodynamic Implications of Income-Transfer Policies for Human Capital Investment and School Effort

The distortion in educational investment in poorer childrenis often attributed to credit market imperfections and henceto the unequal access of children to educational opportunity.However, the distortion might also be attributable to disincentiveeffects that cause children to make inefficient use of educationalopportunities. This possibility is demonstrated for an overlappinggenerations economy with multiple family dynasties in which childrenhave random unobservable abilities and base their school efforton their parents‘ after-tax returns to schooling. Income redistributioncan result in suboptimal effort choices that offset the beneficialeffects of income transfers and sharply lower social welfare.
Numerical analysis of a radiant heat flux calibration system

Heat flux gauges are one of the devices that are used to determine the heat loads to which high-speed aerospace structures are subjected during flight. Prior to installation, these gauges are calibrated. The calibration system must be well understood if the heat flux gauges are to provide useful data during flight tests. A pseudo three-dimensional model of the radiant heat flux gauge calibration system was developed. The radiant heat flux gauge calibration system consists of a graphite plate heater and a circular foil heat flux gauge. The numerical model simulates the combined convection, radiation, and mass loss by chemical reaction on the graphite plate surface. It can be used to identify errors due to heater element erosion, and the deviations in the predicted heat fluxes due to uncertainties in various physical parameters of the system. A fourth-order finite difference scheme is used to solve the steady-state governing equations and to determine the temperature distribution in the gauge and the graphite plate, the incident heat flux on the gauge face, and the flat plate erosion. Initial gauge heat flux predictions from the model are found to be within ±5% of experimental results.
The Project of Land Restitution in Colombia: An Illustration of the Civilizing Force of Hypocrisy?

This article offers a theoretical interpretation of the dispositions on land restitution contained in the famous “Victims’ Bill”, which was debated in the Colombian Congress during the year 2008. The bill included specific mechanisms aimed at guaranteeing the restitution of land to victims of the Colombian armed conflict. At the time, the bill was endorsed by all the main political actors in the country –notably the government and the elites that support it, on the one hand, and victims’ and human rights organizations and other opposition groups, on the other–. The fact that the restitution of land to victims of the Colombian armed conflict was being considered as a serious possibility by all political actors in the country seemed to indicate the existence of a consensus among actors whose positions are ordinarily opposed, on an issue that has traditionally led to high levels of polarization. This consensus is quite puzzling, because it seems to be at odds with the interests and/or the conceptions of justice advocated by these political actors, and because the restitution of land faces enormous
Faster-than-light effects and negative group delays in optics and electronics, and their applications

Recent manifestations of apparently faster-than-light effects confirmed our predictions that the group velocity in transparent optical media can exceed c. Special relativity is not violated by these phenomena. Moreover, in the electronic domain, the causality principle does not forbid negative group delays of analytic signals in electronic circuits, in which the peak of an output pulse leaves the exit port of a circuit before the peak of the input pulse enters the input port. Furthermore, pulse distortion for these 'superluminal' analytic signal scan be negligible in both the optical and electronic domains. Here we suggest an extension of these ideas to the microelectronic domain. The underlying principle is that negative feedback can be used to produce negative group delays. Such negative group delay scan be used to cancel out the positive group delays due to 'transistor latency' as well as the 'propagation delays' due to the interconnects between transistors. Using this principle, it is possible to speed up computer systems.
Branes within branes

Superstring theory has a rich spectrum of solitonic states, and over the last years much has been learned about their important roles in the theory, in strong-weak coupling duality and in resolving singularities [1]. The most important are the BPS states (those in reduced multiplets of supersymmetry) as one can make exact statements about them even at strong coupling, and thus dualities can predict their existence. Many dualities exchange elementary string states with states having Ramond-Ramond gauge charge, which strongly suggests that the two should be considered equally fundamental.
Molecular Indices of Apoptosis Activation in Elastase-Induced Aneurysms After Embolization with Platinum Coils

Background and Purpose— Even though endovascular coils have been widely used for the treatment of intracranial aneurysms, the cellular and molecular responses of aneurysms to the coils after embolization remain poorly understood. The aim of the present study was to understand the mechanism of apoptosis in aneurysms embolized with platinum coils in the rabbit model of elastase-induced aneurysms. Methods— Elastase-induced saccular aneurysms were created at the origin of the right common carotid artery in 30 rabbits. Aneurysms were allowed to mature for 8 weeks, after which 20 aneurysms were embolized with platinum coils by endovascular means. After 2 (n=10) and 4 (n=10) weeks of implantation, aneurysm samples harboring coils were harvested for apoptotic studies. The remaining 10 uncoiled aneurysms were used as controls; additional controls included the left common carotid artery, which had not undergone any surgical procedure. Control samples were harvested at 12 weeks after aneurysm creation. Results— Expression of procaspases-3, -8, and -9 was elevated in coiled aneurysms embolized with platinum coils at both time points when compared with uncoiled aneurysms and the left common carotid artery. Cleaved caspases-3, -8, and -9 were found to be expressed only at 4 weeks after embolization. Cells within the aneurysm cavity were terminal dUTP nick end-labeling–positive at 4 weeks only. These apoptotic cells were identified as smooth muscle actin–positive cells. Expression of tumor necrosis-α was high in coiled aneurysms when compared with controls. There was no significant difference in the expression of Fas ligand among groups. Decreased expression of antiapoptotic proteins Bcl-2 and phospho-Bad, as well as increased expression of proapoptotic proteins Bax and Bid, was observed in coiled aneurysms at both time points. Conclusions— Activation of apoptosis in aneurysms after embolization with platinum coils is induced by both tumor necrosis factor-α–mediated extrinsic and Bcl-2-mediated intrinsic pathways.
Effects of motoneuron properties on reflex stability in spastic subjects: a simulation study

The influence of motoneuron pool properties on the stability of the stretch reflex at the ankle in subjects with spinal cord injury was tested using a comprehensive model of the reflex pathway. This model included the passive and active components of the triceps surae muscles, muscle spindles, neural transport delays, limb mechanical properties, and a lumped parameter model of the motoneuron pool input-output relationship. Simulations show that as the motoneuron firing threshold was reduced (reflecting increased excitability of spinal motoneurons), normal reflex responses became unstable and oscillations developed similar to those observed in spastic patients. In parallel, when reflex delay times typical for triceps surae in man were chosen, and motoneuron excitability increased progressively, oscillatory ankle movements were readily elicited. Conversely, as pathway delays were reduced, reflex stability increased, as :the oscillatory behavior usually damped out. Decreases in motoneuron pool synaptic gain had a stabilizing effect on the reflex response, as low motoneuron gains tended to eliminate oscillatory behavior. Using an Absolute Stability Analysis, we found that reflex pathways containing long neural transport delays and muscles with slow dynamics tended to place the largest stability constraints on the motoneuron pool. These findings support the hypothesis that unstable oscillatory behavior, such as the oscillations observed in clonus, will occur when the motoneuron excitability increases in a reflex pathway containing long delays.
Constraints and Opportunities for the NIEO in Sub-Saharan Africa

Publisher Summary This chapter presents some major characteristics of developing Africa. These features have shaped Africa's past, conditioned efforts and responses, and are likely to cast long shadows on its path into the future. They derive from the peculiarities of Africa's colonization. Africa suffered the humiliation of having been partitioned arbitrarily by the colonial powers without regard to history, culture, and economic and political viability. There was no rational basis for her partition. This explains the large number of mini-states. The chapter also explains the fragility of African governments. Moreover, African colonialism is a recent phenomenon. Its impact, especially on African economies, is visible. The chapter describes constraints and opportunities for the New International Economic Order (NIEO) in sub-Saharan Africa. In the process of establishing a NIEO, Africa has to perceive its goal as essentially one of economic decolonization. This will guide its time frame and its tactics.
Changing stepsize in the integration of differential equations using modified divided differences

Multistep methods for solving differential equations based on numerical integration formulas or numerical differentiation formulas (for stiff equations) require special provision for changing the stepsize. New algorithms are given which make the use of modified divided differences an attractive way to carry out the change in stepsize for such methods. Error estimation and some of the important factors in stepsize selection and the selection of integration order are also considered.
Reasoning with Analogical Representations

Analogical representations have long been of interest to the knowledge representation community. Such representations provide compact encodings of information that can be cumbersome to represent and inefficient to manipulate in sentential languages. In this document, we address the problem of using analogical representations effectively in automated deduction systems. The primary contribution is a formal framework for combining analogical and deductive reasoning. The framework consists of a set of generic operations on analogical structures and accompanying inference methods for integrating analogical and sentential information. The capabilities of the framework are demonstrated for the task of reasoning to extend incomplete maps. The examples presented here have all been solved automatically by an implementation of the integration framework.
Components have test buddies

Most large software systems are architected as component-based systems. In such systems, components are developed and tested separately. As components cooperate for providing services, testing of a component also reveals defects in other components. In this paper we study the role testing of other components plays in finding defects in a component by analyzing defect data of an earlier version of Windows. Our analysis shows that testing of other components often is the largest source of finding defects in a component. The analysis also shows that though many components reveal defects in a component, often a small set of components – the Test Buddies – exists whose testing reveals the vast majority of the defects found by testing other components. The Test Buddies of a component are those with a heavy interaction with the component and represent the high priority customers for testing. The Test Buddy information for a system can be determined by the test data of an earlier release, and then can be used in different ways to improve the testing.
Pólya's Random Walk Theorem

This note presents a proof of Polya's random walk theorem using classical methods from special function theory and asymptotic analysis.
Quotas and the stability of implicit collusion

This paper shows that the imposition of an import quota by one countrycan lead to increased competitiveness; protection can reduce the price in thecountry that imposes the quota, the foreign country, or both. This emergesfrom a model in which the firms are assumed to sustain collusion by the threatof reversion to more competitive pricing. We consider both prices andquantities as the strategic variables and study competition both in thedomestic and the foreign market taken individually, and in the two marketstaken together.
Towards a practical approach to confidential Byzantine fault tolerance

As the world becomes increasingly interconnected, more and more important services such as business transactions are deployed as access-anywhere services - services that are accessible by remote devices through the Internet and mobile networks. Such services often must access confidential data to provide service. For example, an online bank service must access a user’s checking account to process an online transfer request. In such a scenario, guarantees of availability, integrity, and confidentiality are essential. By availability, we mean that services must provide service 24/7 without interruption. By integrity, we mean that services must process clients’ requests correctly. By confidentiality, we mean that services must restrict who sees what data. Given today’s economics and technology that make it infeasible to rigorously test and verify complex components, it is more attractive to allow untrustworthy components to be assembled into a trustworthy system. A traditional Byzantine fault-tolerant (BFT) system runs different implementations of the same service on several replicas and ensures that correct computation is performed by enough correct replicas to mask incorrect replicas [10.1], [10.7], [10.8]. Recent research has shown that BFT systems can be practical for several important services as they can be implemented with low overhead compared to the unreplicated services [10.3].
Communication-Efficient MPC for General Adversary Structures

A multiparty computation (MPC) protocol allows a set of players to compute a function of their inputs while keeping the inputs private and at the same time securing the correctness of the output. Most MPC protocols assume that the adversary can corrupt up to a fixed fraction of the number of players. Hirt and Maurer initiated the study of MPC under more general corruption patterns, in which the adversary is allowed to corrupt any set of players in some pre-defined collection of sets [1]. In this paper we consider this important direction and present improved communication complexity of MPC protocols for general adversary structures. More specifically, ours is the first unconditionally secure protocol that achieves linear communication in the size of Monotone Span Program representing the adversary structure in the malicious setting against any Q2 adversary structure, whereas all previous protocols were at least cubic.
SWEET: Serving the Web by Exploiting Email Tunnels

Open communications over the Internet pose serious threats to countries with repressive regimes, leading them to develop and deploy censorship mechanisms within their networks. Unfortunately, existing censorship circumvention systems do not provide high availability guarantees to their users, as censors can easily identify, hence disrupt, the traffic belonging to these systems using today’s advanced censorship technologies. In this paper, we propose Serving the Web by Exploiting Email Tunnels (SWEET), a highly available censorship-resistant infrastructure. SWEET works by encapsulating a censored user’s traffic inside email messages that are carried over public email services like Gmail and Yahoo Mail. As the operation of SWEET is not bound to any specific email provider, we argue that a censor will need to block email communications all together in order to disrupt SWEET, which is unlikely as email constitutes an important part of today’s Internet. Through experiments with a prototype of our system, we find that SWEET’s performance is sufficient for Web browsing. In particular, regular Websites are downloaded within couple of seconds.
Paths to Market for Supply Push Technology Transfer

The Rehabilitation Engineering Research Center on Technology Transfer (T2RERC) advances the methods of technology transfer through research, transforms technologies into products through development, and facilitates the commercialization of new and improved assistive technology devices. This paper reviews the T2RERC's process and the three primary Paths to Market employed by the T2RERC for new products proceeding through its Supply Push program (Lane, 1999) in a case study format.
Some experiments with real-time decision algorithms

Real-time Decision algorithms are a class of incremental resource-bounded [Horvitz, 89] or anytime [Dean, 93] algorithms for evaluating influence diagrams. We present a test domain for real-time decision algorithms, and the results of experiments with several Real-time Decision Algorithms in this domain. The results demonstrate high performance for two algorithms, a decision-evaluation variant of Incremental Probabilisitic Inference [D'Ambrosio, 93] and a variant of an algorithm suggested by Goldszmidt, [Goldszmidt, 95], PK-reduced. We discuss the implications of these experimental results and explore the broader applicability of these algorithms.
The Cost of Low Fertility in Europe

We analyze the effect of fertility on income per capita with a particular focus on the experience of Europe. For European countries with below-replacement fertility, the cost of continued low fertility will only be observed in the long run. We show that in the short run, a fall in the fertility rate will lower the youth dependency ratio and increase the working-age share, thus raising income per capita. In the long run, however, the burden of old-age dependency dominates the youth dependency decline, and continued low fertility will lead to small working-age shares in the absence of large migration inflows. We show that the currently very high working- age shares generated by the recent declines in fertility and migration inflows are not sustainable, and that significant drops in the relative size of the working-age pop- ulation should be expected. Without substantial adjustments in labor force partici- pation or migration policies, the potential negative repercussions on the European economy are large.
Detection of Interactive Stepping Stones: Algorithms and Confidence Bounds

Intruders on the Internet often prefer to launch network intrusions indirectly, i.e., using a chain of hosts on the Internet as relay machines using protocols such as Telnet or SSH. This type of attack is called a stepping-stone attack. In this paper, we propose and analyze algorithms for stepping-stone detection using ideas from Computational Learning Theory and the analysis of random walks. Our results are the first to achieve provable (polynomial) upper bounds on the number of packets needed to confidently detect and identify encrypted stepping-stone streams with proven guarantees on the probability of falsely accusing non-attacking pairs. Moreover, our methods and analysis rely on mild assumptions, especially in comparison to previous work. We also examine the consequences when the attacker inserts chaff into the stepping-stone traffic, and give bounds on the amount of chaff that an attacker would have to send to evade detection. Our results are based on a new approach which can detect correlation of streams at a fine-grained level. Our approach may also apply to more generalized traffic analysis domains, such as anonymous communication.
Formation Flying Satellites: Control By an Astrodynamicist

Satellites flying in formation is a concept being pursued by the Air Force and NASA. Potential periodic formation orbits have been identified using Hill's (or Clohessy Wiltshire) equations. Unfortunately the gravitational perturbations destroy the periodicity of the orbits and control will be required to maintain the desired orbits. Since fuel will be one of the major factors limiting the system lifetime it is imperative that fuel consumption be minimized. To maximize lifetime we not only need to find those orbits which require minimum fuel we also need for each satellite to have equal fuel consumption and this average amount needs to be minimized. Thus, control of the system has to be addressed, not just control of each satellite. In this paper control of the individual satellites as well as the constellation is addressed from an astrodynamics perspective.