cssi/SciSciGPT-SciSciNet huggingface dataset:
The atmospheres of the hot-Jupiters Kepler-5b and Kepler-6b observed during occultations with Warm-Spitzer and Kepler

This paper reports the detection and the measurements of occultations of the two transiting hot giant exoplanets Kepler-5b and Kepler-6b by their parent stars. The observations are obtained in the near-infrared with Warm-Spitzer Space Telescope and at optical wavelengths by combining more than a year of Kepler photometry. The investigation consists of constraining the eccentricities of these systems and of obtaining broadband emergent photometric data for individual planets. For both targets, the occultations are detected at the 3σ level at each wavelength with mid-occultation times consistent with circular orbits. The brightness temperatures of these planets are deduced from the infrared observations and reach T_(Spitzer) = 1930 ± 100 K and T_(Spitzer) = 1660 ± 120 K for Kepler-5b and Kepler-6b, respectively. We measure optical geometric albedos A_g in the Kepler bandpass and find A_g = 0.12 ± 0.04 for Kepler-5b and A_g = 0.11 ± 0.04 for Kepler-6b, leading to upper an limit for the Bond albedo of A_B ≤ 0.17 in both cases. The observations for both planets are best described by models for which most of the incident energy is redistributed on the dayside, with only less than 10% of the absorbed stellar flux redistributed to the nightside of these planets.
Decomposition theorem for the cd-index of Gorenstein* posets

We prove a decomposition theorem for the cd-index of a Gorenstein* poset analogous to the decomposition theorem for the intersection cohomology of a toric variety. From this we settle a conjecture of Stanley that the cd-index of Gorenstein* lattices is minimized on Boolean algebras.
Improved Direct Product Theorems for Randomized Query Complexity

The "direct product problem'' is a fundamental question in complexity theory which seeks to understand how the difficulty of computing a function on each of k independent inputs scales with k. We prove the following direct product theorem (DPT) for query complexity: if every T$-query algorithmhas success probability at most 1 - \eps in computing the Boolean function f on input distribution mu, then for alpha \leq 1, every alpha \eps Tk-query algorithm has success probability at most (2^{\alpha \eps}(1-\eps))^k in computing the k-fold direct product f^{\otimes k} correctly on k independent inputs from \mu. In light of examples due to Shaltiel, this statement gives an essentially optimal tradeoff between the query bound and the error probability. Using this DPT, we show that for an absolute constant $\alpha > 0$, the worst-case success probability of any $\alpha R_2(f) k$-query randomized algorithm for f^{\otimes k} falls exponentially with k. The best previous statement of this type, due to Klauck, \v{S}palek, and de Wolf, required a query bound of O(bs(f) k). Our proof technique involves defining and analyzing a collection of martingales associated with an algorithm attempting to solve f^{\otimes k}. Our method is quite general and yields a new XOR lemma and threshold DPT for the query model, as well as DPTs for the query complexity of learning tasks, search problems, and tasks involving interaction with dynamic entities. We also give a version of our DPT in which decision tree size is the resource of interest.
One-Dimensional Helical Transport in Topological Insulator Nanowire Interferometers

The discovery of three-dimensional (3D) topological insulators opens a gateway to generate unusual phases and particles made of the helical surface electrons, proposing new applications using unusual spin nature. Demonstration of the helical electron transport is a crucial step to both physics and device applications of topological insulators. Topological insulator nanowires, of which spin-textured surface electrons form 1D band manipulated by enclosed magnetic flux, offer a unique nanoscale platform to realize quantum transport of spin-momentum locking nature. Here, we report an observation of a topologically protected 1D mode of surface electrons in topological insulator nanowires existing at only two values of half magnetic quantum flux (±h/2e) due to a spin Berry’s phase (π). The helical 1D mode is robust against disorder but fragile against a perpendicular magnetic field breaking-time-reversal symmetry. This result demonstrates a device with robust and easily accessible 1D helical electronic states f...
Ubiquity of simplices in subsets of vector spaces over finite fields

We prove that a sufficiently large subset of the d-dimensional vector space over a finite field with q elements, \( \mathbb{F} \)qd, contains a copy of every k-simplex. Fourier analytic methods, Kloosterman sums, and bootstrapping play an important role.
Retrosigmoid Approach for Acoustic Tumor Removal

The retrosigmoid technique has evolved from the traditional suboccipital operation and, when combined with removal of the posterior wall of the internal auditory canal (IAC), affords a wide exposure of the cerebellopontine angle. This approach may be used for acoustic neuromas of all sizes, from intracanalicular, to more than 4 cm from the porus acusticus. Hearing preservation may be attempted and is generally successful in a substantial minority of cases. The facial nerve is readily visualized at the lateral end of the IAC and is at no greater risk than in the translabyrinthine operation. The authors use this approach for all hearing preservation surgery as well as for tumors of more than 3 cm, regardless of hearing.
Is There Natural Language after Data Bases

1. Why Not Data Base Query? The undisputed favorite application for natural language interfaces has been data base query. Why? The reasons range from the relative simplicity of the task, including shallow semantic processing, to the potential real-world utility of the resultant system. Because of such reasons, the data base query task was an excellent paradigmatic problem for computational linguistics, and for the very same reasons it is now time for the field to abandon its protective cocoon and progress beyond this rather limiting task. But, one may ask, what task shall then become the new paradigmatic problem? Alas, such question presupposes that a single, universally acceptable, syntactically and semantically challenging task exists. I will argue that better progress can be made by diversification and focusing on different theoretically meaningful problems, with some research groups opting to investigate issues arisinq from the development of integrated multi-purpose systems.
Kidney Transplantation in Children Younger Than 1 Year Using Cyclosporine Immunosuppression

Objective The optimal age for transplantation in children with end-stage renal disease remains controversial. Supported by national data, many centers recommend dialysis until the child reaches a certain minimum age. The authors' policy, however, has been to encourage living donor (LD) transplants for young children, with no minimum age restriction. Methods Between January 1, 1984, and December 31, 1996, the authors performed 248 kidney transplants in children younger than age 13 years, using cyclosporine as the primary immunosuppressive agent. Recipients were analyzed in three age groups: group 1, younger than age 1 year (n = 26); group 2, age 1 through 4 (n = 92); and group 3, age 5 through 13 (n = 130). Almost all recipients in group 1 underwent a primary LD transplant. Therefore, to compare results more meaningfully among the three age groups, only primary LD transplants were analyzed (group 1, n = 25; group 2, n = 59; group 3, n = 58). Results In primary LD transplants, no significant difference was noted among the age groups in 1- and 5-year patient or graft survival rates. To date, all 25 recipients from group 1 are alive and well; 19 still have a functional original graft. Causes of graft loss in the remaining six recipients were chronic rejection (n = 3), vascular thrombosis (n = 2), and recurrent disease (n = 1). The incidence of acute rejection in group 1 recipients was lower than in the two older groups. However, the incidence of delayed graft function was slightly higher in the youngest group than in the two older groups. For recipients in group 1, growth (as measured by weight) improved significantly posttransplant: the mean standard deviation score rose from -2.8 pretransplant to -0.2 by age 5 and to +1.8 by age 10. The improvement in height was not as dramatic: the mean standard deviation score rose from -3.2 pretransplant to - 1.6 by age 5 and to -1.4 by age 10. Conclusions Kidney transplantation in young children, including those younger than 1 year old, can achieve results comparable to those in older children. As long as an adult LD is available, the timing of the transplant should be based on renal function rather than age.
An Economic Analysis Of The Effectiveness of Thoroughbred Breeder/Owner Incentive Policies

Thoroughbred incentive programs are subsidy policies funded from state parimutuel tax revenue designed to promote regional race horse breeding and ownership. At issue is an ongoing debate concerning the effectiveness of alternative policies. Empirical results indicate that incentive programs have a positive economic effect, but gains to Thoroughbred breeders can be obtained by reallocating tax revenue to non-restricted purses. A policy allocating tax revenue to non-restricted purses shifts yearling demand and increases prices, while breeder subsidies shift only the supply function and therefore lower prices. Consequently, breeder revenues increase in response to a policy thatfavors non-restrictedpurses over subsidies.
The Demand for UN Peacekeeping, 1975–1996

During 1988-97, UN peacekeeping operations expanded by 32 new missions, more than twice the entire number of missions initiated during the United Nations’ first four decades. These new peacekeeping deployments and their added complexity are reflected in current-year nominal spending on UN peacekeeping, which averaged $208.5 million for 1980-88 before increasing by almost one and a half magnitudes to reach a peak of $3.5 billion in 1994’. Since this peak level, UN peacekeeping spending has declined to $3.2 billion in 1995 and $1.35 billion in 1996. This last decrease is largely due to NATO’s assumption of peacekeeping activities in Bosnia by the NATO Implementation Force (IFOR) in December 1995. Despite this downturn, UN peacekeeping expenditures remain at a significantly elevated level over preceding decades and may increase in response to ethnic conflicts and tribalism that still present threats. Ethnic hatreds, once held in check by authoritarian regimes, have erupted into conflict in Eastern Europe and the ex-Soviet republics with the demise of communism (Carment and James 1998). In Africa and the Middle East, tribalism has resulted in warring factions (e.g., Rwanda, Lebanon) that have placed civilian populations in dire straits. Although recent peacekeeping burdens do not rival defense burdens, which for NATO topped $390 billion (in 1990 prices) in 1996 (NATO 1996), peace
Rapid assessment of electrode characteristics for impedance imaging

When a multiplicity of electrodes is applied in one or more rows around a body structure such as the thorax or limb, it is useful to be able to rapidly assess the general status of the electrode-body interface to determine if the skin has been suitably prepared, and that electrode and skin impedance are suitably low. In addition, assessment of the impedance of individual electrodes should precede acquisition of data for image formation. Techniques are presented for assessing the overall skin and electrode impedances relative to the impedance of the body interior and for assessing the integrity of each electrode's contact impedance. Experimental results are given. It was found that the homogeneous saline phantom has negligible skin impedance and negligible reaction impedance. The intact thigh has a high and variable reactive impedance near the skin, which is made more uniform and somewhat lowered by stripping the stratum corneum. After stripping, the real component of skin impedance has approximately half the impedance of the interior structures. >
ON THE ORIGIN OF THE ROTATION CURVES OF DARK MATTER-DOMINATED GALAXIES

Rotation curves of dark matter-dominated galaxies measure the mass profiles of galactic halos and thereby test theories of their cosmological origin. While attention has focused lately on the possible discrepancy at small galactocentric radii between observed rotation curves and the singular density profiles predicted by N-body simulations of the cold dark matter (CDM) model, the observed rotation curves nevertheless contain valuable additional information with which to test the theory and constrain the fundamental cosmological parameters, despite this uncertainty at small radii. An analytical model we derived elsewhere for the postcollapse equilibrium of cosmological halos as truncated, nonsingular, isothermal spheres (TISs) reproduces many of the average properties of halos in CDM simulations to good accuracy, including the density profiles outside the central region. The circular velocity profile of this TIS model, moreover, is in excellent agreement with the observed ones and yields the mass and formation epoch of an observed halo from the parameters of its rotation curve. This allows us to predict correlations among rotation curve parameters, such as the maximum velocity and the radius at which it occurs, for different mass halos forming at different epochs in the CDM model. As an example, we derive the observed vmax-rmax relation analytically, with preference for the flat ΛCDM model.
Response of the Zonal Mean Atmospheric Circulation to El Niño versus Global Warming

The change in the zonal mean atmospheric circulation under global warming is studied in comparison with the response to El Nino forcing, by examining the model simulations conducted for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. In contrast to the strengthening and contraction of the Hadley cell and the equatorward shift of the tropospheric zonal jets in response to El Nino, the Hadley cell weakens and expands poleward, and the jets move poleward in a warmed climate, despite the projected “El Nino–like” enhanced warming over the equatorial central and eastern Pacific. The hydrological impacts of global warming also exhibit distinct patterns over the subtropics and midlatitudes in comparison to the El Nino. Two feasible mechanisms are proposed for the zonal mean circulation response to global warming: 1) The increase in static stability of the subtropical and midlatitude troposphere, a robust result of the quasi-moist adiabatic adjustment to the surface warming, may stabilize the baroclinic eddy growth on the equatorward side of the storm tracks and push the eddy activity and the associated eddy-driven wind and subsidence poleward, leading to the poleward expansion of the Hadley cell and the shift of midlatitude jets; 2) the strengthening of the midlatitude wind at the upper troposphere and lower stratosphere, arguably a consequence of increases in the meridional temperature gradient near the tropopause level due to the tropospheric warming and tropopause slope, may increase the eastward propagation of the eddies emanating from the midlatitudes, and thus the subtropical region of wave breaking displaces poleward together with the eddy-driven circulation. Both mechanisms are somewhat, if not completely, distinct from those in response to the El Nino condition.
Radiative gravitational fields in general relativity I. general structure of the field outside the source

We present a well-defined formal framework, together with appropriate mathematical tools, which allow us to implement in a constructive way, and to investigate in full mathematical details, the Bonnor-Thorne approach to gravitational radiation theory. We show how to construct, within this framework, the general radiative (formal) solution of the Einstein vacuum equations, in harmonic coordinates, which is both past-stationary and past-asymptotically Minkowskian. We investigate the structure of the latter general radiative metric (including all tails and nonlinear effects) both in the near zone and in the far zone. As a side result it is proven that post-Newtonian expansions must be done by using the gauge functions (lg c)^p/c^n (p, n = positive integers).
New fluorinated pyrrolidine and azetidine amides as dipeptidyl peptidase IV inhibitors

Cyclohexylglycine amides of various fluorinated pyrrolidines and azetidines were prepared and tested for activity against dipeptidyl peptidase IV and in vivo in the KK mouse model of type 2 diabetes. The tetrafluoropyrrolidide, cis-3,4-difluoropyrrolidide and the fluorinated azetidides displayed unexpectedly strong activity.
PREPARATION OF TRANS-1,2-DIAMINO-1,2-DIMETHYLCYCLOHEXANE VIA HIGHLY STEREOSELECTIVE OLEFIN OXIDATION BY DINITROGEN TETROXIDE

Abstract Reaction of N2O4 with 1,2-dimethylcyclohexene led to the corresponding dinitro compound 4 with high trans stereoselectivity (>30:1). Catalytic hydrogenation of 4 with Pd(OH)2 on carbon afforded a quantitative yield of (d,l)-1,2-diamino-1,2-dimethylcyclohexane, which was resolved to pure enantiomers with mandelic acid. This approach constitute a simple and potentially general route to interesting new chiral auxiliaries.
PAC learning, VC dimension, and the arithmetic hierarchy

We compute that the index set of PAC-learnable concept classes is m-complete $${\Sigma^{0}_{3}}$$Σ30 within the set of indices for all concept classes of a reasonable form. All concept classes considered are computable enumerations of computable $${\Pi^{0}_{1}}$$?10 classes, in a sense made precise here. This family of concept classes is sufficient to cover all standard examples, and also has the property that PAC learnability is equivalent to finite VC dimension.
Atom Economy: a Challenge for Enhanced Synthetic Efficiency

The sections in this article are Vinylidenes Cycloisomerization of Hydroxyalkynes Reconstitutive Condensation Redox Isomerization Allyl Alcohols Ruthenacyclopentadiene Intermediates Ruthenacyclopentene Intermediates Intermolecular Alkene-Alkyne Coupling Butenolide Formation and Related Reactions Pyran Formation Intramolecular Alkene–Alkyne Coupling [5 + 2] Cycloaddition Vinyl Ketones as Alkyne Partners Allylic C–H Insertion Reactions of Alkenes Allene–Alkene Coupling Heterocycles via Allene–Alkene Coupling Conclusion Acknowledgments Keywords: atom economy; synthetic efficiency; ruthenium complexes; green chemistry
Preferential functionalization on zigzag graphene nanoribbons: first-principles calculations

We investigate the functionalization of functional groups to graphene nanoribbons with zigzag and armchair edges using first-principles calculations. We find that the formation energy for the configuration of the functional groups functionalized to the zigzag edge is ~ 0.2 eV per functional group lower than that to the armchair edge. The formation energy difference arises from a structural deformation on the armchair edge by the functionalization whereas there is no structural deformation on the zigzag edge. Selective functionalization on the zigzag edge takes place at a condition of the temperature and the pressure of ~ 25 °C and 10 − 5 atm. Our findings show that selective functionalization can offer the opportunity for an approach to the separation of zigzag graphene nanoribbons with their solubility change.
Learning, Forgetting, and Sales

Sellers of almost any product or service rarely keep their prices constant through time and frequently offer price discounts or sales. This paper investigates an explanation of sales as a way for uninformed consumers to be willing to experience the product, and learn about its fit, and where informed consumers may forget about (or change) their preferences. We investigate the role of the rate of consumer forgetting on the timing between sales, and of the rate of consumer learning and menu costs on the length of a sale. The rate of consumer forgetting can be linked to the length of purchase cycle and the level of consumer involvement. We show that the discount frequency and the discount depth are increasing in the rate of consumer forgetting, and that the discount frequency is increasing in the learning rate. The duration of a sale is increasing in the rate of consumer forgetting and the rate of consumer learning.
AUTONOMOUS ORBIT AND MAGNETIC FIELD DETERMINATION USING MAGNETOMETER AND STAR SENSOR DATA

A batch filter has been developed to autonomously determine spacecraft orbit and corrections to the Earth's magnetic field model. It uses only magnetometer and star sensor measurements. This filter's aim is to improve the accuracy of magnetometer-based spacecraft orbit determination. Observability of the system is demonstrated through covariance analysis. The results of filtering data from a truth model simulation predict the method's accuracy. The truth model includes random magnetometer noise, random star sensor attitude errors, and high-spatial-frequency magnetic field uncertainties. System accuracy is highest for low altitude, about 500 km, and significant inclination, 45O or larger. Accuracies on the order of 150 m for position and 1 nT for field model coefficients are predicted by the study. The only unobservable situation is that of an orbit with zero inclination and zero eccentricity, but accuracy degrades markedly for nearly circular orbits with low inclination.
Assessing the Impact of Alternative Fair Value Measures on the Efficiency of Project Selection and Continuation

ABSTRACT: We examine how alternative accounting measures of fair value impact the ability of debt covenants to mitigate inefficient investment decisions. In our setting, shareholders make a non-contractible project choice after signing a debt contract. At a later date, the project can be abandoned and new information determines whether shareholders or creditors make that decision. The value of debt covenants depends on their ability to deter costly asset substitution while also mitigating inefficient continuation decisions. A covenant based on a conservative fair value measure tends to perform best in this respect. Departing from purely fair-value-based covenants, an even more conservative covenant based on fair values and historical cost outperforms those based solely on fair values. Notably, the “highest and best use” measure advocated by the FASB performs poorly in deterring the choice of inferior projects. Our results provide a setting in which the contracting efficiencies associated with different ac...
An Axiomatic Theory of Fairness in Network Resource Allocation

We present five axioms for fairness measures in resource allocation. A family of fairness measures satisfying the axioms is constructed. Special cases of this family include &#945;-fairness, Jain's index, and entropy. Properties of fairness measures satisfying the axioms are proven, including Schur-concavity. Among the engineering implications is a generalized Jain's index that tunes the resolution of fairness measure, a new understanding of &#945;-fair utility functions, and an interpretation of ``larger &#945; is more fair''. We also construct an alternative set of axioms to capture system efficiency and feasibility constraints.
Character generation from resistive storage of time derivatives

Recent advances in man-machine communication have stimulated increased interest in techniques and special circuits that generate characters, for graphical and alphanumeric Cathode-Ray-Tube (CRT) display terminals, at the display site. The primary advantage in employing such local character generation is compression of the data that is required to store and communicate a character from the computer to the display---a single binary word of length n is all that is required to instruct the character generator to display one of 2n possible characters. The primary disadvantage of local character generation is display cost, for it is generally considerably less expensive to generate characters from a longer sequence of more elementary commands---for example commands that cause the CRT beam to move right, left, up or down by a minimum resolvable increment. Besides these conflicting costs of data storage and transmission versus local-display generation, several other less tangible criteria such as character stability and fidelity (aesthetics), are instrumental in the design and evaluation of a local character-generation approach.
What Goes into a Medal: Women's Inclusion and Success at the Olympic Games

Th is paper examines determinants of women’s participation and performance in the Olympics. Female inclusion and success are not merely functions of size, wealth, and host advantage, but a more complex process involving the socioeconomic status of women and, more weakly, broad societal attitudes on gender issues. Female labor force participation and educational attainment in particular are tightly correlated with both participation and outcomes, even controlling for per capita income. Female educational attainment is strongly correlated with both the breadth of participation across sporting events and success in those events. Host countries and socialist states also are associated with unusually high levels of participation and medaling by female athletes. Medal performance is aff ected by large-scale boycotts. Opening competition to professionals may have leveled the playing fi eld for poorer countries. But the historical record for women’s medal achievement is utterly distorted by the doping program in the former East Germany, which specifi cally targeted women. At its peak in the 1970s and 1980s, the program was responsible for 17 percent of the medals awarded to women, equivalent to the medal hauls of the Soviet or American team in 1972, the last Olympics not marred by widespread abuse of performance-enhancing drugs.
Designing for Aircraft Structural Crashworthiness

This report describes structural aviation crash dynamics research activities being conducted on general aviation aircraft and transport aircraft. The report includes experimental and analytical correlations of load-limiting subfloor and seat configurations tested dynamically in vertical drop tests and in a horizontal sled deceleration facility. Computer predictions using a finite-element nonlinear computer program, DYCAST, of the acceleration time-histories of these innovative seat and subfloor structures are presented. Proposed application of these computer techniques, and the nonlinear lumped mass computer program KRASH, to transport aircraft crash dynamics is discussed. A proposed FAA full-scale crash test of a fully instrumented radio controlled transport airplane is also described.
Effects of Corporate Diversification on Productivity

Using plant-level observations from the Longitudinal Research Database I show that conglomerates are more productive than stand-alone firms at a given point in time. Dynamically, however, firms that diversify experience a net reduction in productivity. While the acquired plants increase productivity, incumbent plants suffer. Moreover, stock prices track firm productivity and this tracking is equally strong for diversified and stand-alone firms. Therefore, lower transparency of conglomerates is unlikely to explain the discrepancy between productivity and stock prices on average. Finally, I offer some evidence that this discrepancy may arise because conglomerates dissipate rents in the form of higher wages. CORPORATE DIVERSIF ICATION HAS RECEIVED much attention from academics as well as management practitioners. Several papers over the last decade have argued that diversification is related to lower valuation for shareholders. Lang and Stulz ~1994!, for example, find that diversified firms trade at an average discount of about eight percent relative to a portfolio of comparable stand-alone firms. 1 A number of recent studies, however, question the interpretation of these findings or even their validity. Graham, Lemmon, and Wolf ~1998! or Campa and Kedia ~1999! suggest that the discount should not be interpreted as value destruction due to diversification, since firms which diversify are already discounted prior to diversifying. Moreover, Harris ~1998! or Villalonga ~2000! argue that COMPUSTAT segment data are systematically biased in favor of finding a diversification discount.
A new approach to hydrindenones by tautomer-arrested annulations of Fischer carbene complexes

The reactions of 2,6-disubstituted aryl carbene complexes with alkynes give hydrindenone products if a phenol function is present which prevents aromatization to an indene product by a tautomerization of a metal complexed vinyl alcohol intermediate.
Trends in Use of and Reproductive Outcomes Associated With Intracytoplasmic Sperm Injection

vs 34.2%; adjusted relative risk [RR], 0.87; 95% CI, 0.83-0.91). Among cycles without male factor infertility (n = 317 996), ICSI use was associated with lower rates of implantation (23.0% vs 25.2%; adjusted RR, 0.93; 95% CI, 0.91-0.95), live birth (36.5% vs 39.2%; adjusted RR, 0.95; 95% CI, 0.93-0.97), and multiple live birth (30.1% vs 31.0%; adjusted RR, 0.93; 95% CI, 0.91-0.95) vs conventional IVF. CONCLUSIONS AND RELEVANCE Among fresh IVF cycles in the United States, ICSI use increased from 36.4% in 1996 to 76.2% in 2012, with the largest relative increase among cycles without male factor infertility. Compared with conventional IVF, ICSI use was not associated with improved postfertilization reproductive outcomes, irrespective of male factor infertility diagnosis.
Phonon-phason coupling in icosahedral quasicrystals

From relaxation simulations of decoration-based quasicrystal structure models using microscopically based interatomic pair potentials, we have calculated the (usually neglected) phonon-phason coupling constant. Its sign is opposite for the two alloys studied, i-AlMn and i-(Al,Cu)Li; a dimensionless measure of its magnitude relative to the phonon and phason elastic constants is of order 1/10, suggesting its effects are small but detectable. We also give a criterion for when phonon-phason effects are noticeable in diffuse tails of Bragg peaks.
DRAND: Distributed Randomized TDMA Scheduling for Wireless Ad Hoc Networks

This paper presents a distributed implementation of RAND, a randomized time slot scheduling algorithm, called DRAND. DRAND runs in O(delta) time and message complexity where delta is the maximum size of a two-hop neighborhood in a wireless network while message complexity remains O(delta), assuming that message delays can be bounded by an unknown constant. DRAND is the first fully distributed version of RAND. The algorithm is suitable for a wireless network where most nodes do not move, such as wireless mesh networks and wireless sensor networks. We implement the algorithm in TinyOS and demonstrate its performance in a real testbed of Mica2 nodes. The algorithm does not require any time synchronization and is shown to be effective in adapting to local topology changes without incurring global overhead in the scheduling. Because of these features, it can also be used even for other scheduling problems such as frequency or code scheduling (for FDMA or CDMA) or local identifier assignment for wireless networks where time synchronization is not enforced. We further evaluate the effect of the time-varying nature of wireless links on the conflict-free property of DRAND-assigned time slots. This experiment is conducted on a 55-node testbed consisting of the more recent MicaZ sensor nodes.
Improving medical decisions for incapacitated persons: does focusing on "accurate predictions" lead to an inaccurate picture?

The Patient Preference Predictor (PPP) proposal places a high priority on the accuracy of predicting patients’ preferences and finds the performance of surrogates inadequate. However, the quest to develop a highly accurate, individualized statistical model has significant obstacles. First, it will be impossible to validate the PPP beyond the limit imposed by 60%–80% reliability of people’s preferences for future medical decisions—a figure no better than the known average accuracy of surrogates. Second, evidence supports the view that a sizable minority of persons may not even have preferences to predict. Third, many, perhaps most, people express their autonomy just as much by entrusting their loved ones to exercise their judgment than by desiring to specifically control future decisions. Surrogate decision making faces none of these issues and, in fact, it may be more efficient, accurate, and authoritative than is commonly assumed.
Domain and function: a dual-space model of semantic relations and compositions

Given appropriate representations of the semantic relations between carpenter and wood and between mason and stone (for example, vectors in a vector space model), a suitable algorithm should be able to recognize that these relations are highly similar (carpenter is to wood as mason is to stone; the relations are analogous). Likewise, with representations of dog, house, and kennel, an algorithm should be able to recognize that the semantic composition of dog and house, dog house, is highly similar to kennel (dog house and kennel are synonymous). It seems that these two tasks, recognizing relations and compositions, are closely connected. However, up to now, the best models for relations are significantly different from the best models for compositions. In this paper, we introduce a dual-space model that unifies these two tasks. This model matches the performance of the best previous models for relations and compositions. The dual-space model consists of a space for measuring domain similarity and a space for measuring function similarity. Carpenter and wood share the same domain, the domain of carpentry. Mason and stone share the same domain, the domain of masonry. Carpenter and mason share the same function, the function of artisans. Wood and stone share the same function, the function of materials. In the composition dog house, kennel has some domain overlap with both dog and house (the domains of pets and buildings). The function of kennel is similar to the function of house (the function of shelters). By combining domain and function similarities in various ways, we can model relations, compositions, and other aspects of semantics.
Genus zero surface conformal mapping and its application to brain surface mapping

We developed a general method for global conformal parameterizations based on the structure of the cohomology group of holomorphic one-forms for surfaces with or without boundaries (Gu and Yau, 2002), (Gu and Yau, 2003). For genus zero surfaces, our algorithm can find a unique mapping between any two genus zero manifolds by minimizing the harmonic energy of the map. In this paper, we apply the algorithm to the cortical surface matching problem. We use a mesh structure to represent the brain surface. Further constraints are added to ensure that the conformal map is unique. Empirical tests on magnetic resonance imaging (MRI) data show that the mappings preserve angular relationships, are stable in MRIs acquired at different times, and are robust to differences in data triangulation, and resolution. Compared with other brain surface conformal mapping algorithms, our algorithm is more stable and has good extensibility.
Millimeter wave picocellular system evaluation for urban deployments

With the severe spectrum shortage in conventional cellular bands, millimeter wave (mmW) frequencies between 30 and 300 GHz have been attracting considerable attention as a possible candidate for next-generation micro- and picocellular wireless networks. The mmW frequency bands offer orders of magnitude greater spectrum than current cellular microwave frequencies currently deployed below 3 GHz. However, even with typical microcellular radii of 100m to 200m, the propagation of mmW signals in outdoor non line-of-sight (NLOS) links remains challenging and the feasibility of such mmW networks is far from clear. This paper uses recent real-world measurements at 28 GHz to provide the first systematic assessment of mmW picocellular networks. It is found that, even with its limited propagation characteristics, mmW systems can offer an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks with similar cell density. However, it is also shown that such mmW networks will operate in an extremely power-limited regime where the full spatial and bandwidth degrees of freedom are not fully utilized. This power-limited regime contrasts significantly with current bandwidth-limited cellular systems, requiring alternate technologies for mmW systems that may unlock further gains that mmW frequency bands offer.
Microgravimetric and gravity gradient techniques for detection of subsurface cavities

.ABSTRACT Microgravimetric and gravity gradient surveying techniques are applicable to the detection and delineation of shallow subsurface cavities and tunnels. Two case histories of the use of these techniques to site investigations in karst regions are presented. In the first case history, the delineation of a shallow (_ 10 m deep), airfilled cavity system by a microgravimetric survey is demonstrated. Also, application of familiar ring and center point techniques produces derivative maps which demonstrate (1) the use of second derivative techniques to produce a “residual” gravity map, and (2) the ability of first derivative techniques to resolve closely spaced or complex subsurface features. In the second case history, a deeper (-30 m deep), water-filled cavity system is adequately detected by a microgravity survey. Results of an interval (tower) vertical gradient survey along a profile line are presented in the second case history; this vertical gradient survey successfully detected shallow (< 6 m) anomalous features such as limestone pinnacles and clay pockets, but the data are too “noisy” to permit detection of the vertical gradient anomaly caused by the cavity system. Interval horizontal gradients were determined along the same profile line at the second site, and a vertical gradient profile is determined from the horizontal gradient profile by a Hilbert transform technique. The measured horizontal gradient profile and the computed vertical gradient profile compare quite well with corresponding profiles calculated for a two-dimensional model of the cavity system.
Multiple target tracking based on symmetric measurement equations

An approach to track maintenance in multiple target tracking is presented in terms of measurements which are symmetric functions of target positions. In this approach, the data association problem is embedded in the process of target state estimation so that there is no need to consider possible target/measurement associations. For N targets moving in three-dimensional space, the first-order version of the target state estimator is an extended Kalman filter of dimension 6N. Attention is focused on the case of constant-velocity targets with the number of measurements (of a given coordinate) assumed to be equal to the number of targets. >
Diabetic-Associated Stillbirth: Incidence, Pathophysiology, and Prevention

All forms of diabetes during pregnancy are associated with an increased risk for stillbirth, defined as fetal death at greater than 20 weeks. The incidence of stillbirth in women who have diabetes has decreased dramatically with improved diabetes care. Diabetic-associated stillbirth is associated with hyperglycemia, resulting in fetal anaerobic metabolism with hypoxia and acidosis. Prevention of stillbirth in women who have diabetes hinges on intensive multidisciplinary prenatal care with control of blood sugars and appropriate fetal surveillance.
A polynomial time algorithm for the local testability problem of deterministic finite automata

The local testability problem of deterministic finite automata is investigated. A locally testable language is a language with the property that, for some nonnegative integer k, whether or not a word w is in the language depends on (1) the prefix and suffix of w of length k, and (2) the set of substrings of w length k+1, without regard to the order in which these substrings occur. The local testability problem is, given a deterministic finite automation, to decide whether or not it accepts a locally testable language. The authors present an O(n/sup 2/) time algorithm for the local testability problem based on two simple properties that characterize locally testable automata. >
Changes in volatility of credit spread and market efficiency during rapid growth of credit-related securities

This paper investigates the changes in credit spread volatility during 1993–2001. We find that the credit spreads between junk-grade corporate bonds and Treasury bonds were significantly more volatile in the second half of this period when credit-related securities became popular. In contrast, investment-grade bonds exhibited no significant change in volatility. The junk bonds variance ratios changed from being less than one to greater than one. Using the GJR-Garch model, the conditional volatilities of junk bonds increased in the second half of the period and the mean reversion speeds slowed, suggesting a longer time for mean reversion to occur. Our analysis rules out treasury volatility, credit spread level, equity market return, T-bill rate, curvature of the Treasury curve, financial crisis, quantity of defaults and standard deviation of defaults as explanations for the increase in junk bond volatility. In contrast, volatility of equity returns provides a partial explanation of junk bond spread volatil...
Investing in Indonesia’s Education: Allocation, Equity, and Efficiency of Public Expenditures

What are the current trends and main characteristics of public education spending in Indonesia? Is education spending insufficient? Are expenditures in education efficient and equitable? This study reports the first account of Indonesia's aggregated (national and sub-national) spending on education, as well as the economic composition of education spending and its breakdown by programs. It presents estimations of the expected (average) level of education spending for a country with its economic and social characteristics. This analysis sheds light on the efficiency and equity of education spending by presenting social rates of return by level of education, by assessing the adequacy of current teacher earnings relative to other paid workers and the distribution of teachers across urban, rural, and remote regions, and by identifying the main determinants of education enrollment. It concludes that the current challenges in Indonesia are no longer defined by the need of additional spending, but rather the need to improve the quality of education services, and to improve the efficiency of education expenditures by re-allocating teachers to undersupplied regions and re-adjusting the spending mix within and between education programs for future additional spending in the sector. The study finds that poverty and student-aged labor are also significant constraints to education enrollment, stressing the importance of policies aimed at addressing demand-side factors.
Mid-Infrared Interferometry on Spectral Lines. I. Instrumentation

The Infrared Spatial Interferometer at University of California, Berkeley has been outfitted with a filter-bank system to allow interferometric observations of mid-infrared spectral lines with very high spectral resolution (λ/Δλ ~ 105). This paper describes the design, implementation, and performance of the matched 32 channel filter-bank modules, and new spectral-line observations of Mars and IRC +10216 are used to demonstrate their scientific capability. In addition, observing strategies are discussed for accurate calibration of fringe visibilities in spectral lines, despite strong atmospheric fluctuations encountered in the infrared.
On the evolutionary history of stars and their fossil mass and light

The total extragalactic background radiation can be an important test of the global star formation history (SFH). Using direct observational estimates of the SFH, along with standard assumptions about the initial mass function (IMF), we calculate the total extragalactic background radiation and the observed stellar density today. We show that plausible SFHs allow a significant range in each quantity, but that their ratio is very tightly constrained. Current estimates of the stellar mass and extragalactic background are difficult to reconcile, as long as the IMF is fixed to the Salpeter slope above 1 Msun. The joint confidence interval of these two quantities only agrees with that determined from the allowed range of SFH fits at the 3-sigma level, and for our best-fit values the discrepancy is about a factor of two. Alternative energy sources that contribute to the background, such as active galactic nuclei (AGN), Population III stars, or decaying particles, appear unlikely to resolve the discrepancy. However, changes to the IMF allow plausible solutions to the background problem. The simplest is an average IMF with an increased contribution from stars around 1.5--4 Msun. A ``paunchy'' IMF of this sort could emerge as a global average if low mass star formation is suppressed in galaxies experiencing rapid starbursts. Such an IMF is consistent with observations of star-forming regions, and would help to reconcile the fossil record of star formation with the directly observed SFH.
La construcción del lenguaje en Paraguay: fonologías, ortografías e ideologías en un país multilingüe

This paper analyzes a controversy about the inclusion of the Guarani language in the bilingual education system of Paraguay. The controversy is the result of the country’s complex sociolinguistic reality: Guarani is an official language and an important emblem of national identity, but also a language of inferior status to Spanish, which is known as a situation of “diglossia”. Moreover the speakers have negative attitudes towards their own speech practices, characterized by phenomena of convergence and mixing. This, some scholars identified as a “second order diglossia” between everyday discourse and the speech community’s ideological construction of “real” Guarani. In a controversial measure, government language planners have accredited a “hybrid” Guarani version that would allow language borrowings from Spanish to remedy this situation and to facilitate the teaching of Guarani, bringing the official version closer to everyday speech. This measure caused a heated debate about the version of Guarani that should be used in education. The debate will be used here to explore the dominant language ideologies in the country that are responsible for the difficulties in bilingual education and for the ambiguities in the use of and attitudes towards Guarani.
Do Poorer Countries Have Less Capacity for Redistribution

Development aid and policy discussions often assume that poorer countries have less internal capacity for redistribution in favor of their poorest citizens. The assumption is tested for 90 developing countries. Most countries fall into one of two groups: those with little or no realistic prospect of addressing extreme poverty through redistribution from the rich and those that would appear to have ample scope for such redistribution. Economic growth tends to move countries from the first group to the second. Thus the appropriate balance between growth and redistribution strategies can be seen to depend on the level of economic development.
Breakeven costs of storage in optimized solar energy systems

Abstract This paper describes the results of an analysis of the breakeven cost, or value, of energy storage to solar energy systems. The value of storage depends strongly both on the solar fraction of the solar energy system in which the storage is employed and on the cost of the collectors used in the system. Various strategies for dealing with this ambiguity are presented. For a broad class of technically and economically practical solar energy systems, storage costs need only be low enough to make a system employing very small amounts of storage practical. Reductions in the cost of collectors will thereafter produce greater reductions in the total system costs or provide greater fuel displacement at constant total system cost than will reductions in the cost of storage, within the limits discussed in the body of the paper. The analysis makes use of a simple, accurate representation of solar energy system performance which may prove useful in other contexts.