cssi/SciSciGPT-SciSciNet huggingface dataset:
Fast Fourier transform telescope

We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore's law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog{sub 2}N rather than N{sup 2}) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.
International Remittances and Financial Inclusion in Sub-Saharan Africa

This paper uses World Bank survey data, including about 10,000 households in five countries -- Burkina Faso, Kenya, Nigeria, Senegal, and Uganda -- to investigate the link between international remittances and households' financial inclusion in Sub-Saharan Africa. The paper finds that receiving international remittances increases the probability that the household opens a bank account in all the five countries. This result is robust to controlling for the potential endogeneity of remittances, using as instruments indicators of the migrants' economic conditions in the destination countries.
Neural tube defects.

Neural tube defects (NTDs) are a group of malformations of the brain and spinal cord that originate at various times during gestation. The most common NTDs are anencephaly and meningomyelocele, which arise during the process of neurulation, a well-defined period between the 17th and 30th day after ovulation. These NTDs are clinically apparent by being open, ie, leaving nervous tissue exposed, in contrast to postneurulation NTDs that are skin covered. The incidence of NTDs is declining in several areas of the world, including the United States. While the reasons for this are unclear, there seems to be some effect from prenatal diagnosis, genetic counseling, and possibly nutritional supplementation. (JAMA1988;259:558-562)
Beyond Gaussian Pyramid: Multi-skip Feature Stacking for action recognition

Most state-of-the-art action feature extractors involve differential operators, which act as highpass filters and tend to attenuate low frequency action information. This attenuation introduces bias to the resulting features and generates ill-conditioned feature matrices. The Gaussian Pyramid has been used as a feature enhancing technique that encodes scale-invariant characteristics into the feature space in an attempt to deal with this attenuation. However, at the core of the Gaussian Pyramid is a convolutional smoothing operation, which makes it incapable of generating new features at coarse scales. In order to address this problem, we propose a novel feature enhancing technique called Multi-skIp Feature Stacking (MIFS), which stacks features extracted using a family of differential filters parameterized with multiple time skips and encodes shift-invariance into the frequency space. MIFS compensates for information lost from using differential operators by recapturing information at coarse scales. This recaptured information allows us to match actions at different speeds and ranges of motion. We prove that MIFS enhances the learnability of differential-based features exponentially. The resulting feature matrices from MIFS have much smaller conditional numbers and variances than those from conventional methods. Experimental results show significantly improved performance on challenging action recognition and event detection tasks. Specifically, our method exceeds the state-of-the-arts on Hollywood2, UCF101 and UCF50 datasets and is comparable to state-of-the-arts on HMDB51 and Olympics Sports datasets. MIFS can also be used as a speedup strategy for feature extraction with minimal or no accuracy cost.
Mobile application usability: conceptualization and instrument development

This paper presents a mobile application usability conceptualization and survey instrument following the 10- step procedure recommended by MacKenzie et al. (2011). Specifically, we adapted Apple's user experience guidelines to develop our conceptualization of mobile application usability that we then developed into 19 first-order constructs that formed 6 second-order constructs. To achieve our objective, we collected four datasets: content validity (n = 318), pretest (n = 440), validation (n = 408), and cross-validation (n = 412). The nomological validity of this instrument was established by examining its impact on two outcomes: continued intention to use and mobile application loyalty. We found that the constructs that represented our mobile application usability conceptualization were good predictors of both outcomes and compared favorably to an existing instrument based on Microsoft's usability guidelines. In addition to being an exemplar of the recent procedure of MacKenzie et al. to validate an instrument, this work provides a rich conceptualization of an instrument for mobile application usability that can serve as a springboard for future work to understand the impacts of mobile application usability and can be used as a guide to design effective mobile applications.
The Tully-Fisher relation at intermediate redshifts

Motivated by recent pioneering measurements of galaxy kinematics at intermediate redshifts, we have begun a pilot survey to measure rotation curves for blue, star-forming galaxies between 0.05<z<0.35. The scientific impetus for such measurements is to construct internal velocity - luminosity relations at redshifts substantial enough to make cosmological and evolutionary tests. Departures from a fiducial relation as a function of redshift are sensitive to both space-time curvature and the evolution of the mass-to-light ratio in galaxies. Because of this ambiguity -- curvature vs. evolution -- kinematics should be viewed as a new cosmological tool at intermediate redshifts to be combined with additional measurements. In particular, the apparent internal velocities, colors, surface-brightness, and image shape are all unaffected by curvature, so that this ensemble of observables can be used unambiguously to explore galaxy evolution. Here we discuss a well-defined method of target selection which assures efficient measurement of spatially and spectrally resolved kinematics, namely rotation curves. Spatial resolution is critical since it is difficult to use integrated line-widths to distinguish between, for example, a low-mass star-forming galaxy and a high-mass galaxy with a central star-burst. For 18 of 19 appropriately selected galaxies to B<20.5 from Bershady et al (1994), we have successfully measured rotation curves using the KAST spectrograph on the Lick 3m telescope with 1-2 hour integrations for each target. As a sanity check, we present preliminary results for half of our sample: We measure H0 to be ~75 km/s/Mpc at a median redshift of 0.15.
Fine-grained classification of pedestrians in video: Benchmark and state of the art

A video dataset that is designed to study fine-grained categorisation of pedestrians is introduced. Pedestrians were recorded “in-the-wild” from a moving vehicle. Annotations include bounding boxes, tracks, 14 keypoints with occlusion information and the fine-grained categories of age (5 classes), sex (2 classes), weight (3 classes) and clothing style (4 classes). There are a total of 27,454 bounding box and pose labels across 4222 tracks. This dataset is designed to train and test algorithms for fine-grained categorisation of people; it is also useful for benchmarking tracking, detection and pose estimation of pedestrians. State-of-the-art algorithms for fine-grained classification and pose estimation were tested using the dataset and the results are reported as a useful performance baseline.
A correctness result for online robust PCA

We study the problem of sequentially recovering a sparse vector x t and a vector from a low-dimensional subspace l t from knowledge of their sum m t = x t + l t . If the primary goal is to recover the low-dimensional subspace where the l t 's lie, then the problem is one of online or recursive robust principal components analysis (PCA). To the best of our knowledge, this is the first correctness result for this problem. We prove that if a good estimate of the initial subspace is available; the l t 's obey certain denseness and slow subspace change assumptions; and the support of x t changes either at every frame or at least every so often, then with high probability, the support of x t will be recovered exactly, and the error made in estimating x t and l t will be small. An example where this problem occurs is in separating a sparse foreground and a slowly changing dense background from surveillance videos.
A lagrange multiplier test of uniformity against beta alternatives

A test of uniformity is derived as a Lagrange Multiplier test against the beta family. As such, it has desirable properties against beta alternatives. Monte Carlo results show that it also has good power against non-beta alternatives.
Totally Real Origami and Impossible Paper Folding

Origami is the ancient Japanese art of paper folding. It is possible to fold many intriguing geometrical shapes with paper [M]. In this article, the question we will answer is which shapes are possible to construct and which shapes are impossible to construct using origami. One of the most interesting things we discovered is that it is impossible to construct a cube with twice the volume of a given cube using origami, just as it is impossible to do using a compass and straight edge. As an unexpected surprise, our algebraic characterization of origami is related to David Hilbert's 17th problem. Hilbert's problem is to show that any rational function which is always non-negative is a sum of squares of rational functions [B]. This problem was solved by Artin in 1926 [Ar]. We would like to thank John Tate for noticing the relationship between our present work and Hilbert's 17th problem. This research is the result of a project in the Junior Fellows Program at The University of Texas. The Junior Fellows Program is a program in which a junior undergraduate strives to do original research under the guidance of a faculty mentor. The referee mentioned two references which the reader may find interesting. "Geometric Exercises in Paper Folding" addresses practical problems of paper folding [R]. Arnong many other things, Sundara Row gives constructions for the 5-gon, the 17-gon, and duplicating a cube. His constructions, however, use more general folding techniques than the ones we consider here. Felix Klein cites Row's work in his lectures on selected questions in elementary geometry [K]. In order to understand the rules of origami construction, we will first consider a sheet of everyday notebook paper. Our work with notebook paper will serve as an intuitive model for our definition of origami constructions in the Euclidean plane. There are four natural methods of folding a piece of paper. The methods will serve as the basis of the definition of an origami pair. We construct the line L1, by folding a crease between two different corners of the paper. Another line may be constructed by matching two corners. For example, if corners or and Sy are matched, the crease formed, L2, will be the perpendicular bisector of the segment orSy. Another natural construction is matching one line to another line. For instance, ,8^y, the paper's edge, and L2 are lines. If we lay ,8^y upon L2 and form the crease, then we obtain L3 which is the angle bisector of the two lines. If we start with two parallel lines in this third construction, then we will just get a parallel line half way in between. The fourth and final construction which seems natural is consecutive folding. This is similar to rolling up the sheet of paper only one does not roll it up, he folds it up. More explicitly, start with a piece of paper with two creases on it as in Figure 2. Fold along line Ll and do not unfold the piece of paper. Notice that line L2 lies
Long double stranded RNA is present in scrapie infected cells and tissues

Despite decades of research efforts, the nature of the infectious agent causing scrapie and other Transmissible Spongiform Encephalopathies (TSE) remains an enigma. The protein-only prion hypothesis posits that an abnormal conformer of a host protein is the infectious agent. Virus and virino theories include host-independent nucleic acids in the genome of the infectious agent, in addition to the protein component (a host protein in the case of virino, and a viral protein in the case of a virus). Viral or sub-viral nucleic acids have long been sought in scrapie to explain the existence of multiple agent strains. Despite a plethora of different approaches to the search, no scrapie-specific nucleic acid sequences have been found in infected cells or tissues. Most viruses induce synthesis of long double stranded RNA (dsRNA) during their replication in cells, and thus the presence of long dsRNA would be an indication of viral infection in cells. J2 monoclonal antibody against long dsRNA is a useful tool for easy screening of cells and tissues for the presence of suspected viral infection; however, this antibody has not previously been used for testing of scrapie infected tissues. Here, we present evidence for long dsRNA in scrapie infected cells and tissues. Such dsRNA is also found in scrapie free tissue culture cells. We believe this may be the first evidence of viral infection in scrapie susceptible and infected cells.
The Geometry of Generalized Binary Search

This paper investigates the problem of determining a binary-valued function through a sequence of strategically selected queries. The focus is an algorithm called Generalized Binary Search (GBS). GBS is a well-known greedy algorithm for determining a binary-valued function through a sequence of strategically selected queries. At each step, a query is selected that most evenly splits the hypotheses under consideration into two disjoint subsets, a natural generalization of the idea underlying classic binary search. This paper develops novel incoherence and geometric conditions under which GBS achieves the information-theoretically optimal query complexity; i.e., given a collection of N hypotheses, GBS terminates with the correct function after no more than a constant times logN queries. Furthermore, a noise-tolerant version of GBS is developed that also achieves the optimal query complexity. These results are applied to learning halfspaces, a problem arising routinely in image processing and machine learning.
Transformations in China's population policies and demographic structure

. We use data from a 1992 national fertility survey to analyze China's changing demographic patterns between 1970 and 1989, covering marriage, childbearing, fertility and the gender composition of children. The analysis focuses on the relationship between population control policies and the behavior of successive marriage cohorts. Adopting a regression approach, we characterize a set of stylized demographic features in China over the two decades, including new results on women's average age at first marriage and first births, number of children per couple, and sex ratios among children. China's changing demographic patterns differed significantly among urban, township and rural populations.
Technological foundations and future directions of large-scale integrated electronics

The technological base of the electronics industry has undergone dramatic change in the past 20 years, largely related to the expansion of the use of materials technology. With the invention of the transistor in 1948, semiconductor materials processing provided the technology for an entirely new class of electronic devices. The invention of the monolithic integrated circuit in 1958 extended the use of materials technology to the formation of complete circuit functions on chips of semiconductor. We are now entering another phase of the expansion of materials technology, in which complete equipment components will be processed on slices of semiconductor.
With an Eye Open and a Round Chambered: Explaining the Afghan Insider Threat and its Implications for Sustained Partnership

This article presents ethnographic data and an analytical framework concerning the recent spike in Afghan National Security Force (ANSF) ‘insider’ or ‘green-on-blue’ attacks on NATO forces. This data was collected as part of an in-depth, multi-level case study of NATO partnering efforts with the Afghan Defence and Interior ministries, the Afghan National Army, the Afghan National Police and Afghan Local Police. Preliminary findings support the argument that, in addition to ANSF infiltration and coercion by the Taliban and Haqqani network, cross-cultural friction and contextual stress on Afghan troops are strong contributors to the rise in insider attacks. Additionally, emotional intelligence, cultural awareness and conflict resolution skills are shown to be important mitigating factors.
Endogenous market structure and the growth and welfare effects of economic integration

Abstract This paper studies the growth and welfare effects of integration in a world economy populated by global oligopolists. In economies that move from autarky to trade, growth and welfare rise because exit of domestic firms is more than compensated by entry of foreign firms so that integration generates a larger, more competitive market where firms have access to a larger body of technological spillovers that support faster growth. The effects of a gradual reduction of tariffs are different because economies start out from a situation where all firms already serve all markets. In this case, the global number of firms falls so that the variety of consumption goods and the diversity of innovation paths fall. The surviving firms, on the other hand, are larger and exploit static and dynamic economies of scale to a larger degree. These homogenization and rationalization effects work in opposite directions. Under plausible conditions, the rationalization effect dominates and growth and welfare rise.
PREEMPTIVE EPIDURAL ANALGESIA AND RECOVERY FROM RADICAL PROSTATECTOMY: A RANDOMIZED CONTROLLED TRIAL

Context.—Preemptive analgesia can decrease the sensitization of the central nervous system that would ordinarily amplify subsequent nociceptive input, but a clear demonstration of its clinical efficacy is necessary for it to become a routine component of acute pain therapy.Objective.—To determine the impact of preemptive epidural analgesia on postoperative pain and other clinically important outcome variables after radical retropubic prostatectomy.Design and Setting.—A block randomized double-blind clinical trial lasting 20 months at a single academic medical center.Patients.—A total of 100 generally healthy and neurologically intact patients scheduled for radical retropubic prostatectomy for the treatment of prostate cancer in whom an epidural catheter for treating postoperative pain was to be placed prior to the induction of general anesthesia.Interventions.—Epidural bupivacaine, epidural fentanyl, or no epidural drug was administered prior to induction of anesthesia and throughout the entire operation, followed by aggressive postoperative epidural analgesia for all patients.Main Outcome Measures.—Daily pain scores during hospitalization and pain scores obtained 3.5, 5.5, and 9.5 weeks after hospital discharge.Results.—The patients who received epidural fentanyl or bupivacaine prior to surgical incision (preemptive analgesia) experienced 33% less pain while hospitalized (P=.007). Pain scores in those receiving preemptive analgesia were significantly lower at 9.5 weeks (P=.02), but were not significantly different at 3.5 or 5.5 weeks. At 9.5 weeks, 32 (86%) of 37 patients receiving preemptive analgesia were pain-free compared with 9 (47%) of 19 control patients (P=.004). Patients receiving preemptive analgesia were more active 3.5 weeks after surgery (P=.01), but not at 5.5 or 9.5 weeks.Conclusions.—Even in the presence of aggressive postoperative pain management, preemptive epidural analgesia significantly decreases postoperative pain during hospitalization and long after discharge, and is associated with increased activity levels after discharge.
Topological mirror symmetry with fluxes

Motivated by SU(3) structure compactifications, we show explicitly how to construct half-flat topological mirrors to Calabi-Yau manifolds with NS fluxes. Units of flux are exchanged with torsion factors in the cohomology of the mirror; this is the topological complement of previous differential-geometric mirror rules. The construction modifies explicit SYZ fibrations for compact Calabi-Yaus. The results are of independent interest for SU(3) compactifications. For example one can exhibit explicitly which massive forms should be used for Kaluza-Klein reduction, proving previous conjectures. Formality shows that these forms carry no topological information; this is also confirmed by infrared limits and old classification theorems.
Hereditary Hemorrhagic Telangiectasia and Disseminated Intravascular Coagulation: A New Clinical Syndrome

In summary, 47 patients with documented HHT and a bleeding problem were referred to San Joaquin Hematology Oncology Medical Group over a 2-year period. Fifty-one percent of patients were noted to have an associated DIC syndrome and of these 24 patients, 19 had acute DIC episodes, six had chronic DIC, six presented with diffuse, recurrent deep venous thrombosis and of these six, three suffered pulmonary emboli. Other defects were also noted and were thought to be coincidental defects. This syndrome should be readily considered and searched for when seeing patients with HHT, especially if significant hemorrhage or thrombosis is present. It should further be appreciated that many patients with HHT and bleeding are candidates for the development of acute or chronic DIC and thus a "mini" Kasabach-Merritt syndrome. When patients with HHT present with undue bleeding, this syndrome should be appreciated, searched for from the clinical and laboratory standpoint and, when found, treated in the appropriate manner with supportive therapy, mini-heparin or antiplatelet therapy as the clinical situation dictates.
Values, Errors, and Precautions

Abstract In the environmental health literature, errors in interpreting studies or data are not infrequent. Many are of the Type II variety. Common solecisms of this type are: treating the criterion of p < 0.05 as a sacrament; demanding complete confounder control; arguing for the existence of phantom confounders; arguing that the effect size is trivial; building nonveridical models; arguing for no effect from inadequate sample size; demanding causal proof; arguing that causality is reversed; conducting a ballot of published studies. These are examined in this paper.
Conjugated Linoleic Acids Alter Body Composition Differently According to Physiological Age in Moulard Ducks

ABSTRACT Conjugated linoleic acids (CLA) have been shown to have remarkable yet inconsistent metabolic effects in mice, rats, hamsters, chickens, cattle, and humans. In particular, effects on lipogenesis vary with tissue, physiological state, and species. In this study we tested the hypothesis that CLA would differentially affect ducks of the same genetic background but of differing age. Growing (7 wk) and maintenance (11 wk) Moulard ducks were grouped by age and fed a standard diet supplemented with 5% soybean oil (control) or 5% CLA isomer mixture. Birds were slaughtered after 3 or 6 wk for assessment of body composition including adipose, liver, viscera, and empty carcass weight. Serum nonesterified fatty acid (NEFA) and glucose concentrations were evaluated, and gene targets were cloned from the duck to use in quantifying mRNA abundance for genes involved in lipogenesis (fatty acid synthase, FAS; acetyl-CoA carboxylase, ACC) and lipid oxidation (carnitine palmitoyl transferase-1, CPT-1) in liver tissue from maintenance birds. After 3 wk, the growing CLA group exhibited a 24% decrease in dissectible adipose tissue (P
Rapid Molecular Cloud and Star Formation: Mechanisms and Movies

We demonstrate that the observationally inferred rapid onset of star formation after parental molecular clouds have assembled can be achieved by flow-driven cloud formation of atomic gas, using our previous three-dimensional numerical simulations. We postprocess these simulations to approximate CO formation, which allows us to investigate the times at which CO becomes abundant relative to the onset of cloud collapse. We find that global gravity in a finite cloud has two crucial effects on cloud evolution. (1) Lateral collapse (perpendicular to the flows sweeping up the cloud) leads to rapidly increasing column densities above the accumulation from the one-dimensional flow. This in turn allows fast formation of CO, allowing the molecular cloud to appear rapidly. (2) Global gravity is required to drive the dense gas to the high pressures necessary to form solar-mass cores, in support of recent analytical models of cloud fragmentation. While the clouds still appear supersonically turbulent, this turbulence is relegated to playing a secondary role, in that it is to some extent a consequence of gravitational forces.
Activated carbon as the reagent for the oxidative cyclization of fullerene adducts

Abstract Reaction of C 60 with diethylaminopropyne leads to cyclobutene adduct 1 , which upon acid hydrolysis provides a facile synthetic route to fullerene adduct 2 . Subsequent oxidative cyclization involving activated carbon yields the novel fullerene lactone 3 .
X-Ray Interferometry

For the astronomer, X-ray interferometry is the theory and practice of building dilute aperture telescopes for studying celestial X-ray sources. The short wavelengths and high surface brightness of X-ray sources will make the eventual scientific payoff very high, with direct imaging of the event horizons of black holes as the centerpiece. In this article, we review the history of X-ray interferometry and discuss the recent technical developments toward astronomical applications. We present several mission concepts and show they are achievable with today’s technology.
Continuous formulations and analytical properties of the link transmission model

Abstract The link transmission model (LTM) has great potential for simulating traffic flow in large-scale networks since it is much more efficient and accurate than the Cell Transmission Model (CTM). However, there lack general continuous formulations of LTM, and there has been no systematic study on its analytical properties such as stationary states and stability of network traffic flow. In this study we attempt to fill the gaps. First we apply the Hopf–Lax formula to derive Newell’s simplified kinematic wave model with given boundary cumulative flows and the triangular fundamental diagram. We then apply the Hopf–Lax formula to define link demand and supply functions, as well as link queue and vacancy functions, and present two continuous formulations of LTM, by incorporating boundary demands and supplies as well as invariant macroscopic junction models. With continuous LTM, we define and solve the stationary states in a road network. We also apply LTM to directly derive a Poincare map to analyze the stability of stationary states in a diverge-merge network. Finally we present an example to show that LTM is not well-defined with non-invariant junction models. We can see that Newell’s model and continuous LTM complement each other and provide an alternative formulation of the network kinematic wave theory. This study paves the way for further extensions, analyses, and applications of LTM in the future.
A review of the real space renormalization group analysis of the two-dimensional Coulomb gas, the Kosterlitz-Thouless-Berezinski transition, and extensions to a layered vortex gas

Abstract Fundamental properties of the Kosterlitz-Thouless-Berezinskii (KTB) transition which occurs in systems in the universality class of the two-dimensional X-Y model are reviewed here with an emphasis on the real-space renormalization-group analysis used to derive the recursion relations. A derivation of the unique temperature dependence of the correlation length of this system will be presented and the signatures of the KTB transition in electronic transport measurements will be explained. Extensions of this model and technique to layered superconductors will also be presented. The size of the three-dimensional (3D) critical region, the nature of the 3D cross-over, and the effect of a finite electric current will be discussed.
Chiral Crown Conformation of Rh2(S-PTTL)4: Enantioselective Cyclopropanation with α-Alkyl-α-diazoesters

Herein, we provide crystallographic and computational evidence that Hashimoto’s Rh2(S-PTTL)4 catalyst adopts a “chiral crown” conformation with a reactive chiral face and an unreactive achiral face. In Rh2(S-PTTL)4, all four tert-butyl groups are aligned on the same face of the catalyst, and each C−(t-Bu) bond is roughly parallel to the central Rh−Rh bond. This orients the four phthalimido groups on the opposite face of the catalyst. Also described is an enantioselective and diastereoselective protocol for intermolecular Rh2(S-PTTL)4-catalyzed cyclopropanation using α-alkyl-α-diazoesters. Intermolecular cyclopropanation is selective over two competing intramolecular pathways: C−H insertion and β-hydride elimination. On the basis of density functional theory calculations and the Davies−Singleton model for cyclopropanation, a model for asymmetric induction is proposed.
Synthesis of high-energy magnet materials: Coercivity mechanism, surface studies, and new alloys

Abstract To date, in spite of extensive studies, only five high energy permanent magnet materials have been discovered. Hence there is an ongoing search for new materials. One, SmTi(Fe, Co)11, is promising. One characteristic required of a material is high uniaxial magnetic anisotropy. This is supplied by the rare earth crystal field interaction. This interaction is now understood well enough to have predictive value. A new use of Auger spectroscopy has revealed that the grains in Nd-Fe-B magnets are covered by a neodymium-rich film about 30–50 A thick. This iron-deficient layer is proposed to be of crucial value for high coercivity. High energy magnets are in widespread use but mostly in high technology applications. Cheaper magnets are needed for normal uses, e.g. household appliances. Lowering cost and obtaining higher flux materials are the greatest technological challenges. Understanding coercivity is the greatest scientific challenge.
STABLE FUNCTIONS AND COMMON STABILIZATIONS OF HEEGAARD SPLITTINGS

We present a new proof of Reidemeister and Singer's Theorem that any two Heegaard splittings of the same 3-manifold have a common stabilization. The proof leads to an upper bound on the minimal genus of a common stabilization in terms of the number of negative slope inflection points and type-two cusps in a Rubinstein-Scharlemann graphic for the two splittings.
MIMO radar: Snake oil or good idea?

MIMO communication is theoretically superior to conventional comm. under certain conditions, and MIMO comm. also appears to be practical and cost effective in the real world for some applications. It is natural to suppose that the same is true for MIMO radar, but the situation is not so clear. Researchers claim many advantages of MIMO radar relative to phased array radars (e.g., better detection performance, better angular resolution, better angular measurement accuracy, improved robustness against RFI & ECM & multipath, etc.). We will evaluate such assertions from a system engineering viewpoint. In particular, there are serious tradeoffs of MIMO vs. phased array radars relative to cost, system complexity and risk, considering numerous real world effects that are not included in most theoretical analyses. Moreover, in many cases one can achieve essentially the same radar system improvement with phased array radars using simpler less expensive and less risky algorithms. We evaluate roughly a dozen asserted advantages of MIMO radar relative to phased arrays.
Making connections: engineering ethics on the World Wide Web

This paper focuses on the use of the World Wide Web in courses and course units dealing with engineering ethics and/or the social implications of engineering. Course materials and other resources for use by students and faculty are discussed and a new website, the Web Clearinghouse for Engineering and Computing Ethics, is introduced. Course materials and resources found on the Web include: ethics centers that focus on engineering ethics and/or other fields of professional ethics; case studies and other instructional materials; course syllabi; codes of engineering ethics; ethics pages of professional societies; papers, articles and reports with relevance to engineering and computer ethics; on-line ethics journals and newsletters; and primary source archives. The Web lends itself for use as a place to post a "living" course syllabus, with hypertext links to on- and off-site material containing course information and assignments as well as information on content and pedagogical techniques of interest to faculty who are developing and teaching courses in engineering and computing ethics. By illustrating in real-time the interconnectedness of information from engineering, the humanities and the social sciences, the Web serves as a tangible metaphor for the interdisciplinary approach necessary for a complete examination of ethics in engineering.
Cosmic Ray Origins: An Introduction

Abstract Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.
Demonstrating worker quality through strategic absenteeism

Determining the productivity of individual workers engaged in team production is difficult. Monitoring expenses may be high, or the observable output of the entire team may be some single product. One way to collect information about individual productivity is to observe how total output changes when the composition of the team changes. While some employers may explicitly shift workers from team to team for exactly this reason, the most common reasons for changes in team composition are at least partly voluntary: vacation time and sick days. In this paper, we develop a model of optimal absenteeism by employees which accounts for strategic interactions between employees. We assume the employer uses both observed changes in output and the strategies of the employees to form beliefs about a given worker's type. We argue that the model we develop is applicable to a variety of workplace situations where signaling models are not, because it allows a worker's decisions to provide information about other workers, as well as about himself.
ON THE HIGHER ORDER CORRECTIONS TO HEAVY QUARK EFFECTIVE THEORY

We show that different ways of deriving the Heavy Quark Effective Theory (HQET) lead to equivalent theories. The equivalence can be established through a careful redefinition of the field variables. We demonstrate the equivalence to order 1/m5 in the presence of a constant electric field.
Dependency Rates and Private Savings Behavior in Developing Countries

Empirical results establishing a firm empirical relationship between dependency rates and savings behavior in developing countries are still lacking. Two demographic extensions of the representative household's stochastic dynamic optimization problem are presented. The relationship between expected dependency rates and consumption growth is shown to depend on two parameters: demographically varying committed consumption and the intertemporal elasticity of substitution. Thus, the expected path of demographic variables can provide information on consumer willingness to smooth consumption, and on the savings responsiveness to changes in the real interest rate.
Slotted Optical Burst Switching (SOBS) networks

In the paper, we study Optical Burst Switching (OBS) networks. Since OBS still suffers high loss ratio due to the lack of buffer at the OBS core routers, we study methods to reduce the loss without using optical buffers. We consider time-slotted OBS called Slotted OBS (SOBS), where routers are synchronized and only send fixed length bursts at the beginning of time slots. Our simulation results show that SOBS reduces the packet loss probability significantly. Moreover, we show that SOBS can be implemented with little or no additional cost and has other advantages such as providing better support for Quality of Service (QoS).
Effects of Boundary-Layer Ingestion on the Aero-Acoustics of Transonic Fan Rotors

The use of boundary-layer-ingesting, embedded propulsion systems can result in inlet flow distortions where the interaction of the boundary layer vorticity and the inlet lip causes horseshoe vortex formation and the ingestion of streamwise vortices into the inlet. A previously-developed body-force-based fan modeling approach was used to assess the change in fan rotor shock noise generation and propagation in a boundary-layer-ingesting, serpentine inlet. This approach is employed here in a parametric study to assess the effects of inlet geometry parameters (offset-to-diameter ratio and downstream-to-upstream area ratio) on flow distortion and rotor shock noise.Mechanisms related to the vortical inlet structures were found to govern changes in the rotor shock noise generation and propagation. The vortex whose circulation is in the opposite direction to the fan rotation (counter-swirling vortex) increases incidence angles on the fan blades near the tip, enhancing noise generation. The vortex with circulation in the direction of fan rotation (co-swirling vortex) creates a region of subsonic relative flow near the blade tip radius which decreases the sound power propagated to the far-field.The parametric study revealed that the overall sound power level at the fan leading edge is set by the ingested streamwise circulation, and that for inlet designs in which the streamwise vortices are displaced away from the duct wall, the sound power at the upstream inlet plane increased by as much as 9 dB. By comparing the far-field noise results obtained to those for a conventional inlet, it is deduced that the changes in rotor shock noise are predominantly due to the ingestion of streamwise vorticity.Copyright © 2012 by ASME
Experimental and Computational Investigation of the NASA Low-Speed Centrifugal Compressor Flow Field

An experimental and computational investigation of the NASA Lewis Research Center's low-speed centrifugal compressor (LSCC) flow field was conducted using laser anemometry and Dawes' three-dimensional viscous code. The experimental configuration consisted of a backswept impeller followed by a vaneless diffuser. Measurements of the three-dimensional velocity field were acquired at several measurement planes through the compressor. The measurements describe both the throughflow and secondary velocity field along each measurement plane. In several cases the measurements provide details of the flow within the blade boundary layers. Insight into the complex flow physics within centrifugal compressors is provided by the computational fluid dynamics analysis (CFD), and assessment of the CFD predictions is provided by comparison with the measurements. Five-hole probe and hot-wire surveys at the inlet and exit to the impeller as well as surface flow visualization along the impeller blade surfaces provided independent confirmation of the laser measurement technique. The results clearly document the development of the throughflow velocity wake that is characteristic of unshrouded centrifugal compressors.
Climate Change: Sources of Warming in the Late 20th Century

The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.
Computational aeroacoustics - Issues and methods

Computational fluid dynamics (CFD) has made tremendous progress especially in aerodynamics and aircraft design over the past 20 years. An obvious question to ask is "why not use CFD methods to solve aeroacoustics problems?" Most aerodynamics problems are time independent, whereas aeroacoustics problems are, by definition, time dependent. The nature, characteristics, and objectives of aeroacoustics problems are also quite different from the commonly encountered CFD problems. There are computational issues that are unique to aeroacoustics. For these reasons computational aeroacoustics requires somewhat independent thinking and development. The objectives of this paper are twofold. First, issues pertinent to aeroacoustics that may or may not be relevant to computational aerodynamics are discussed. The second objective is to review computational methods developed recently that are designed especially for computational aeroacoustics applications. Some of the computational methods to be reviewed are quite different from traditional CFD methods. They should be of interest to the CFD and fluid dynamics communities.
Estimation of tip shape for carrot classification by machine vision

Tip shape has been identified as an important carrot feature which is a major concern to both consumers and in post harvest operations. A classification method can help carrot breeders to measure the success of their breeding operations. Based on the Freeman chain code, a curvature profile was developed. Using a non-linear least squares technique known as the Marquardt method, the curvature profile was reduced to six parameters describing the carrot tip. These parameters were used to develop a Bayes decision function which classified carrot tips into five classes (sharp tapered to extremely blunt tips). This method was tested on 250 carrots. Of the 250 carrots tested, 14% were misclassified.
The effect of problem severity, managerial and organizational capacity, and agency structure on intergovernmental collaboration: evidence from local emergency management

Like most public managers nowadays, local emergency managers operate within complex, uncertain environments. Rapid changes in the scope and severity of the issues increase the extent of intergovernmental collaboration necessary to address such challenges. Using a large data set of county emergency management agency directors, variations in intergovernmental collaboration reflect influences from problem severity, managerial capacity, and structural factors. The results demonstrate that public managers who perceive problems as severe, possess specific managerial skills, lead high-capacity organizations, and operate in less complex agency structures collaborate more often and more effectively across governmental boundaries.
Doc2b enrichment enhances glucose homeostasis in mice via potentiation of insulin secretion and peripheral insulin sensitivity.

Aims/hypothesis Insulin secretion from pancreatic beta cells and insulin-stimulated glucose uptake into skeletal muscle are processes regulated by similar isoforms of the soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) and mammalian homologue of unc-18 (Munc18) protein families. Double C2 domain β (Doc2b), a SNARE- and Munc18-interacting protein, is implicated as a crucial effector of glycaemic control. However, whether Doc2b is naturally limiting for these processes, and whether Doc2b enrichment might exert a beneficial effect upon glycaemia in vivo, remains undetermined.
Single-molecule probes

The technology to rapidly manipulate and screen individual molecules lies at the frontier of measurement science, with impacts in bio- and nano-technology. Fundamental biological and chemical processes can now be probed with unprecedented detail, one molecule at a time. These single molecule probes are most often fluorescent dye molecules embedded in a material or attached to a target molecule, such as a protein or nucleic acid, whose behavior us under study. The fluorescence from a single dye molecule can be detected, its spectrum and lifetime measured and its absorption or emission dipole calculated. From this information, the rotational and translational dynamics of the fluorophore can be calculated, as can details of its photophysics. To the extent that these properties reflect the properties of the target molecule, we can use these fluorescent tags to probe the dynamics and structure of the target. In this work we discuss the dependence of the physical and photophysical dynamics of fluorescent molecules on their local environment, and we use confocal microscopy to study single molecules in thin films, on surfaces, and in various liquid and gaseous environments.
Fundamentals of Tribology at the Atomic Level

Tribology, the science and engineering of solid surfaces in moving contact, is a field that encompasses many disciplines: solid state physics, chemistry, materials science, and mechanical engineering. In spite of the practical importance and maturity of the field, the fundamental understanding of basic phenomena has only recently been attacked. In this paper we will attempt to define some of these problems and indicate some profitable directions for future research. We make three broad classifications: (1) fluid properties--compression, rheology, additives and particulates; (2) material properties of the solids--deformation, defect formation and energy loss mechanisms; and (3) interfacial properties--adhesion, friction chemical reactions, and boundary films. Research in the categories has traditionally been approached by considering macroscopic material properties. Recent activity has shown that some issues can be approached at the atomic level: that is, the atoms in the materials can be manipulated both experimentally and theoretically, and can produce results related to macroscopic phenomena. This experimental and theoretical activity is reviewed and related to the traditional research areas.
Jet fragmentation functions in PbPb and pp collisions at 2.76 TeV with CMS

Abstract The jet fragmentation function of inclusive jets with p T > 100 GeV/c in PbPb collisions is measured for reconstructed charged particles with p T > 1 GeV/c within the jet cone. A data sample of PbPb collisions collected in 2011 at a center-of-mass energy of s N N = 2.76 TeV corresponding to an integrated luminosity of 129 μ b − 1 is used. The results for PbPb collisions as a function of collision centrality are compared to reference distributions based on pp data collected at the same collision energy. A centrality-ordered modification of the fragmentation function is revealed. For the most central collisions a significant rise of the PbPb/pp fragmentation function ratio for the softest fragmentation products with p T 3 GeV/c is observed.