cssi/SciSciGPT-SciSciNet huggingface dataset:
Learning from the Chinese miracle : development lessons for Sub-Saharan Africa

A notable contrast in modern economic history has been the rapid economic growth of China and the slower and volatile economic growth in Sub-Saharan Africa. As the engagement between the two continues to grows, there will be a greater cross-fertilization of experiences. Total factor productivity comparisons suggest that capital accumulation in China coupled with more efficient factor usage explains the differential with Africa. Although the two have similar populations and patterns of inequality, their growth trajectories have been divergent. What can Africa learn from China? Although the lessons vary depending on country location and resource endowment, seven basic lessons are visible. First, the political economy of Chinese reforms and the shared gains between political elites and the private sector can be partially transplanted to the African context. Second, the Chinese used diaspora capital and knowledge in the early reform years. Third, rural reforms in China helped accelerate economic takeoff through a restructuring of property rights and a boost to both savings rates and output. Fourth, Chinese growth has taken place in the context of a competitive exchange rate. Five, port governance in China has been exemplary, and African landlocked economies can benefit significantly from port reform in the coastal countries. Six, China has experimented with a degree of decentralization that could yield benefits for many Sub-Saharan African countries. Seventh, Africa can learn from Chinas policies toward autonomous areas and ethnic minorities to stave off conflict. Africa can learn from Chinas experiences and conduct developmental experiments for poverty alleviation goals.
The effects of baryonic cooling on the concentration–mass relation

I re-examine the relation between virial mass and concentration for groups and clusters of galaxies as measured in a number of recent works. As previously noted by several authors, low-mass clusters and groups of galaxies display systematically larger concentrations than simple prescriptions based on pure N-body simulations would predict. This implies an observed concentration–mass relation with a substantially larger slope/normalization than expected from theoretical investigations. Additionally, this conclusion seems to be quite independent of selection effects, holding for both lensing based and X-ray based cluster samples. In order to shed new light on this issue I employ a simple spherical halo model containing, in addition to dark matter, also stars and hot diffuse gas in proportions and with distributions in agreement with the most recent observations. Moreover, I include the contraction effect experienced by dark matter due to the cooling of baryons in the very central part of the structure itself. The resulting modified concentration–mass relation is steeper than the theoretical input one, because star formation is fractionally more efficient in low-mass objects. However, the effect is non-vanishing at all masses, thus resulting also in a larger normalization. Overall the new relation provides a better representation of the observed one for almost all catalogues considered in this work, although the specific details depend quite significantly on the baryon fraction prescription adopted. Specifically, the observed concentration–mass relation seems to favour a scenario where the stellar mass fraction in large clusters of galaxies is substantially lower than several works have found. Anyhow, the same effect could also be produced by a redistribution of baryons within the structure. Moreover, the concentration of a number of high-mass objects seems to be significantly lower even than the predictions based on pure N-body simulations, and they are hence unaccounted for in the modified scenario that is proposed here. Finally I use this simple model to show how the estimated concentration of cosmic structures is expected to be overestimated as a function of the radial range covered by the analysis.
The verifying compiler, a grand challenge for computing research

The ideas of program verification date back to Turing and von Neumann, who introduced the concept of an assertion as the specification of an interface between parts of a program. The idea of mechanical theorem proving dates back to Leibniz; it has been explored in practice on modern computers by McCarthy, Milner, and many others since. A proposal for 'a program verifier', combining these two technologies, was the subject of a Doctoral dissertation by James C. King, submitted at the Carnegie Institute of Technology in 1969.Early attempts at automatic program verification were premature. But much progress has been made in the last thirty five years, both in hardware capacity and in the software technologies for verification. I suggest that the renewed challenge of an automatic verifying compiler could provide a focus for interaction, cross-fertilisation, advancement and experimental evaluation of all the technologies of interest in this conference.Perhaps by concerted international effort, we may be able to meet this challenge, only fifty years after it was proposed by Jim King. We only have fifteen years left to do it.
Research Involving Children: Recommendations of the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research

Throughout history, children have been subjects of research. A legendary Persian prince is said to have isolated newborn babies from all human speech in hopes of discovering whether language was natural and spontaneous. Queen Caroline of England recruited children from a foundling hospital in order to test Jenner9s vaccination on them before it was applied to her own royal progeny. The modern controversy over research with children and the retarded can be traced to events at Willowbrook State Hospital for the Mentally Retarded where, during the 1950s and 1960s, healthy mentally retarded children were infected with mild hepatitis in order to study the natural history of the disease. That research aroused great public controversy and its merits and faults are debated even today. It initiated a discussion within and without the medical profession over whether any invasion or manipulation of the body or person of a nonconsenting subject could ever be ethically justified, apart from expectation of benefit to that subjct.1 The prevailing codes of ethics governing the use of human subjects for experimentation are curiously ambivalent about children. The progenitor of these codes, The Code of Nuremberg, if taken literally, would exclude children as subjects, for it requires the voluntary consent of the subject "as absolutely essential," without any provision for proxy consent.1 The World Medical Association9s Declaration of Helsinki, on the other hand, states that for nontherapeutic research involving legally incompetent subjects, "the consent of the legal guardian should be procured."3(p277) This position has been adopted by the American Medical Association:
Business Power and Tax Reform: Taxing Income and Profits in Chile and Argentina

This article examines efforts to increase taxation of highly concentrated, undertapped income and profits in Latin America in the aftermath of structural adjustment. Argentina has advanced further than Chile in two policy areas: corporate taxation, which taps firm-level profits; and tax agency access to bank information, which helps reduce income tax evasion. These outcomes are explained by drawing on the classic concepts of business instrumental power, which entails political actions, and structural power, which arises from investment decisions. In Chile, strong instrumental power removed reforms in both areas from the policy agenda. In Argentina, much weaker instrumental power at the cross-sectoral level facilitated corporate tax increases. Bank information access was expanded after Argentina's 2001 crisis weakened the financial sector's instrumental power and reduced structural power.
Porous Carbon Supports: Recent Advances with Various Morphologies and Compositions

The importance of porous carbon as the support material is well recognized in the catalysis community, and it would be even more attractive if several characteristics are considered, such as the stability in acidic and basic media or the ease of noble metal recovery through complete burn off. Because it is still difficult to obtain constant properties even from batch to batch, activated carbons are not popular in industrial catalysis now. During the past decade, the rapid development of nanotechnology has boosted the carbon field, and a number of novel carbons with unique morphologies (such as carbon nanospheres, graphene or sheet-like carbon, and ordered mesoporous carbon) and composites (such as nitrogen-doped carbon and carbon nitride) are emerging, which at the same time greatly benefit heterogeneous catalysis. Metal nanoparticles or metal oxides supported on those carbon supports resulted in interesting and exceptional performances in various catalytic processes, such as selective oxidations, hydrogenations, and oxygen reduction reactions. In this contribution, we review recent progress of porous carbon supports with different morphologies and compositions.
Global Survey of Development Banks

Historically, development banks have been an important instrument of governments to promote economic growth by providing credit and a wide range of advisory and capacity building programs to households, small and medium enterprises, and even large private corporations, whose financial needs are not sufficiently served by private commercial banks or local capital markets. During the current financial crisis, most development banks in Latin America, followed by Asia, Africa, and Europe, have assumed a countercyclical role by scaling up their lending operations exactly when private banks experienced temporary difficulties in granting credit to the private sector. Despite the importance of development banks during crisis and non-crisis periods, little is known about them. This survey examines how development banks operate, what their policy mandates are, what financial services they offer, which type of clients they target, how they are regulated and supervised, what business models they have adopted, what governance framework they have, and what challenges they face. It also examines the countercyclical role played by development banks during the recent financial crisis. This survey is based on new data that have been collected from 90 national development banks in 61 countries.
Vasopressin-dependent inhibition of the C-type natriuretic peptide receptor, NPR-B/GC-B, requires elevated intracellular calcium concentrations.

Natriuretic peptides bind their cognate cell surface guanylyl cyclase receptors and elevate intracellular cGMP concentrations. In vascular smooth muscle cells, this results in the activation of the type I cGMP-dependent protein kinase and vasorelaxation. In contrast, pressor hormones like arginine-vasopressin, angiotensin II, and endothelin bind serpentine receptors that interact with Gq and activate phospholipase Cβ. The products of this enzyme, diacylglycerol and inositol trisphosphate, activate the conventional and novel forms of protein kinase C (PKC) and elevate intracellular calcium concentrations, respectively. The latter response results in vasoconstriction, which opposes the actions of natriuretic peptides. Previous reports have shown that pressor hormones inhibit natriuretic peptide receptors NPR-A or NPR-B in a variety of different cell types. Although the mechanism for this inhibition remains unknown, it has been universally accepted that PKC is an obligatory component of this pathway primarily because pharmacologic activators of PKC mimic the inhibitory effects of these hormones. Here, we show that in A10 vascular smooth muscle cells, neither chronic PKC down-regulation nor specific PKC inhibitors block the AVP-dependent desensitization of NPR-B even though both processes block PKC-dependent desensitization. In contrast, the cell-permeable calcium chelator, BAPTA-AM (1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid, tetraacetoxymethyl ester), abrogates the AVP-dependent desensitization of NPR-B, and ionomycin, a calcium ionophore, mimics the AVP effect. These data show that the inositol trisphosphate/calcium arm of the phospholipase C pathway mediates the desensitization of a natriuretic peptide receptor in A10 cells. In addition, we report that CNP attenuates AVP-dependent elevations in intracellular calcium concentrations. Together, these data reveal a dominant role for intracellular calcium in the reciprocal regulation of these two important vasoactive signaling systems.
Synthesis and biological activity of 2-(4,5-dihydroisoxazol-5-yl)-1,3,4-oxadiazoles

Acid hydrazides were coupled with acrylic acid derivatives and cyclodehydration gave 1,3,4-oxadiazoles. Lastly, in-situ nitrile oxide formation from aryl oximes treated with sodium hypochlorite, and subsequent 1,3-dipolar cycloaddition to the exomethylene moiety delivered 2-(4,5-dihydroisoxazol-5-yl)-1,3,4-oxadiazoles. This library was evaluated in a high-throughput screen at Dow AgroSciences. Several compounds were active against fungal pathogens and pest insects.
Synthetic studies of nucleoside antibiotics: a formal synthesis of (+)-sinefungin.

A formal synthesis of (+)-sinefungin 1 is described. The C-6′ and C-9′ stereogenic centers of sinefungin were constructed stereoselectively by efficient catalytic asymmetric syntheses. The key strategy for the construction of the C-6′ stereocenter involves alkylation of a protected ribose-derived triflate with alkynyl-lithium, Sharpless asymmetric epoxidation of the corresponding allylic alcohol followed by a regioselective epoxide-ring opening with diisopropoxytitanium diazide. The C-9 amino acid stereochemistry was established by a rhodium chiral bisphosphine-catalyzed asymmetric hydrogenation of an α-(acylamino)acrylate derivative. The resulting amino acid derivative has been previously converted to (+)-sinefungin 1.
Novel inhibitors of guanase

Abstract Synthesis and guanase inhibitory activity of two novel 5:7-fused heterocycles, 15 and 16 , containing the imidazo[4,5- e ][1,4]diazepine ring system, have been reported.
Optimizing Vibration Isolation of Flex Circuits in Hard Disk Drives

A “flex circuit” is a laminate of polyimide substrate, adhesive, and copper conductors that is used to connect the stationary electronic components in a computer hard disk drive to the rotating arm that positions read/write heads above the disks. The flex circuit’s transverse and longitudinal vibrations couple with the arm, and those motions, although seemingly small, degrade performance during seek operations from one data track to another. The flex circuit and arm mechanism is defined by a number of geometric parameters, and some latitude is available at the design stage for choosing dimensions and angles so as to minimize vibration transmission from the flex circuit to the arm. In this paper, the results of parameter, optimization, and experimental studies are discussed with a view toward improving isolation of the arm from vibration of the flex circuit in one or several modes. Particularly for the mechanism’s odd modes, the flex circuit’s free length and the relative attachment angle between the arm’s centerline and the circuit can each be chosen to significantly reduce vibration transmission. A genetic algorithm was applied to minimize a metric of vibration coupling in several vibration modes, and, in the case study examined, vibration isolation was improved by over 80%. fDOI: 10.1115/1.1891813g
Severe plastic deformation through adiabatic shear banding in Fe–C steels

Abstract Severe plastic deformation is observed within adiabatic shear bands in iron–carbon steels. These shear bands form under high strain rate conditions, in excess of 1000 s −1 , and strains in the order 5 or greater are commonly observed. Studies on shear band formation in a ultra-high carbon steel (1.3% C) are described in the pearlitic condition. A hardness of 11.5 GPa (4600 MPa) is obtained within the band. A mechanism is described to explain the high strength based on phase transformation to austenite from severe plastic deformation and adiabatic heating. Rapid re-transformation leads to an ultra-fine ferrite grain size containing carbon principally in the form of nano-size carbides. It is proposed that the same mechanism explains the ultra-high strength of iron–carbon steels observed in ball-milling, ball drop tests and in severely deformed wires.
Cup and cap products in intersection (co)homology

Abstract We construct cup and cap products in intersection (co)homology with field coefficients. The existence of the cap product allows us to give a new proof of Poincare duality in intersection (co)homology which is similar in spirit to the usual proof for ordinary (co)homology of manifolds.
Turbulent Mixing Noise from Supersonic Jets

There is now a substantial body of theoretical and experimental evidence that the dominant part of the turbulent noise of supersonic jets is generated directly by the large turbulence structures/instability waves of the jet flow. Earlier, Tam and Burton provided a description of the physical mechanism by which supersonically traveling instability waves can generate sound efficiently. They used the method of matched asymptotic expansions to construct an instability wave solution which is valid in the far field. The present work is an extension of the theory of Tam and Burton. It is argued that the instability wave spectrum of the jet may be regarded as generated by stochastic white noise excitation at the nozzle lip region. The reason why the excitation has white noise characteristics is that near the nozzle lip region the flow in the jet mixing layer has no intrinsic length and time scales. The present stochastic wave model theory of supersonic jet noise contains a single unknown multiplicative constant. Comparisons between the calculated noise directivities at selected Strouhal numbers and experimental measurements of a Mach 2 jet at different jet temperatures have been carried out. Favorable agreements are found.
C6 substitution of inosine using hexamethylphosphorous triamide in conjunction with carbon tetrahalide or N-halosuccinimide†

Abstract Herein we report the facile conversion of 2′,3′,5′-tri- O -acetylinosine to three different nucleoside analogs via reaction of hexamethylphosphorous triamide and an organic halide. Acetyl-protected 6-bromopurine riboside, 6-chloropurine riboside and N 6 , N 6 -dimethyladenosine can each be prepared in good yield from 2′,3′,5′-tri- O -acetylinosine, HMPT and halide. The major product of the reaction is determined by the identity of the halide used and the reaction temperature.
Direct lactonization of alkenols via osmium tetroxide-mediated oxidative cleavage.

A highly efficient, mild, and simple protocol is presented for the tandem OsO4-mediated oxidative cleavage/oxidative lactonization of alkenols to lactones. The protocol couples the OsO4-catalyzed oxidative cleavage of olefins with Oxone as the co-oxidant with the direct oxidation of aldehydes in alcoholic solvents to their corresponding esters.
Origins and renormalization of the superparticle spectrum

Abstract The importance of Yukawa contributions to the renormalization of the spectrum in non-minimal supersymmetric models is illustrated in the cases of explicit lepton number violation (leading to the possibility of singly produced sneutrinos at LEP energies), an intermediate scale singlet neutrino and negative mass squared parameters (possibly modifying fine-tuning considerations), and a grand-unified sector. The relevance of model-dependent renormalization to the supersymmetric flavor problem is emphasized. Sources of the flavor problem, some of which are newly identified, as well as possible solutions, are discussed and classified. It is then shown that gravitational interactions could lead (via a quadratically divergent singlet) to simple realizations of some of the low-energy frameworks that attempt to resolve the flavor problem.
Synthesis of 3-Hydroxyhexacyclo-[6.5.0.03,7.04,12.08,10.09,13]tridecane

The title compound, 8, has been prepared in 24% overall yield via a seven-step synthesis by starting with 3-hydroxyhexacyclo[6.5.0.03,7.04,12.08,10 –.09,13tridecan-6-one (1).
Feedforward control of data rate in wireless networks

This paper develops a feedforward approach to data-rate control in wireless networks. The development is based on designing an optimal but noncausal controller and its subsequent modification, which leads to a causal implementable suboptimal controller driven by an estimate of the bit-error probability. It is shown that this controller results in a minimum of 5%-85% increase in average throughput without additional power utilization, as compared with fixed data rate operation.
Organochlorine pesticides and liver cancer deaths in the United States, 1930–1972☆

Abstract Animal studies have shown the liver to be the primary target organ following prolonged periods of absorption of toxic doses of organochlorine pesticides. Therefore, the core of our presentation is aimed at the liver. Since studies in our laboratory have been concerned primarily with DDT, aldrin, and dieldrin, these compounds are being given primary consideration.
System Simulations of Ds-Trd and Th-Ppm for Ultra-Wide Band (UWB)Wireless Communications

AbstractFollowing FCC approval of ultra-wide band (UWB) radio rules for commercial applications in 2002, a UWB radio physical layer standard is currently under development. Although the UWB transmitting UWB band are spelled out by the FCC, neither UWB signal forms nor modulation schemes are defined by the regulations, stated in ref. [1]. This paper presents the models of two types of impulse radio UWB modulation systems and their simulation performance. They are direct sequence UWB (DS-UWB) and time hopping UWB (TH-UWB). Unique ways of modulating and positioning the impulses, as in transmitted-reference delay (TRD) modulation and pulse-position modulation (PPM) , can result in the simple UWB radio architectures. Systems of TRD for DS-UWB and PPM for TH-UWB are simulated under the same UWB working data rate and under the same AWGN (additive white Gaussian noise) channel conditions. The simulation shows that DS-TRD system presents superior performance over PPM-TH system, which is shown in the comparison cha...
Smoke Gets in Your Eyes: Cigarette Tax Salience and Regressivity

Recent work suggests that consumers respond differently to taxes that are included in a good's posted price and taxes that are added upon checking out at the register. This paper investigates how the government's choice between these posted and register taxes affects the distribution of a tax's burden. We show that when high- and low-income consumers differ in their attentiveness to register taxes, policymakers can lessen a tax's regressivity by manipulating the fraction of a tax that is added at the register. We then turn to the case of cigarettes, and investigate whether high- and low-income consumers do in fact differ in their attentiveness to register taxes on that good. To answer that question, we link state and time variation in cigarette excise and sales tax rates to survey data about cigarette consumption from the Behavioral Risk Factor Surveillance System. Whereas both high- and low-income consumers respond to cigarette excise taxes (which appear in the posted price), we find that only low-income consumers respond to sales taxes on cigarettes (which are added at the register). Our results suggest that policymakers can ease the financial burden of cigarette taxes on the poor by levying such taxes at the register instead of including them in the cigarette's posted price.
Fractal and smoothness properties of space-time Gaussian models

Spatio-temporal models are widely used for inference in statistics and many applied areas. In such contexts, interests are often in the fractal nature of the sample surfaces and in the rate of change of the spatial surface at a given location in a given direction. In this paper, we apply the theory of Yaglom (1957) to construct a large class of space-time Gaussian models with stationary increments, establish bounds on the prediction errors, and determine the smoothness properties and fractal properties of this class of Gaussian models. Our results can be applied directly to analyze the stationary spacetime models introduced by Cressie and Huang (1999), Gneiting (2002), and Stein (2005), respectively.
A computational account of the development of the generalization of shape information

Abecassis, Sera, Yonas, and Schwade (2001) showed that young children represent shapes more metrically, and perhaps more holistically, than do older children and adults. How does a child transition from representing objects and events as undifferentiated wholes to representing them explicitly in terms of their attributes? According to RBC (Recognition-by-Components theory; Biederman, 1987), objects are represented as collections of categorical geometric parts (‘‘geons’’) in particular categorical spatial relations. We propose that the transition from holistic to more categorical visual shape processing is a function of the development of geon-like representations via a process of progressive intersection discovery. We present an account of this transition in terms of DORA (Doumas, Hummel, & Sandhofer, 2008), a model of the discovery of relational concepts. We demonstrate that DORA can learn representations of single geons by comparing objects composed of multiple geons. In addition, as DORA is learning it follows the same performance trajectory as children, originally generalizing shape more metrically⁄holistically and eventually generalizing categorically.
D-brane effective field theory from string field theory

Abstract Open string field theory is considered as a tool for deriving the effective action for the massless or tachyonic fields living on D-branes. Some simple calculations are performed in open bosonic string field theory which validate this approach. The level truncation method is used to calculate successive approximations to the quartic terms φ 4 , (A μ A μ ) 2 and [A μ ,A ν ] 2 for the zero momentum tachyon and gauge field on one or many bosonic D-branes. We find that the level truncation method converges for these terms within 2–4% when all massive fields up to level 20 are integrated out, although the convergence is slower than exponential. We discuss the possibility of extending this work to determine the structure of the nonabelian Born–Infeld theory describing the gauge field on a system of many parallel bosonic or supersymmetric D-branes. We also describe a brane configuration in which tachyon condensation arises in both the gauge theory and string field theory pictures. This provides a natural connection between recent work of Sen and Zwiebach on tachyon condensation in string field theory and unstable vacua in super Yang–Mills and Born–Infeld field theory.
A Tale of Two Rigidities: Sticky Prices in a Sticky‐Information Environment

Macroeconomic models with microeconomic foundations allow for comparisons with macro and micro empirical evidence. This paper proposes a model wherein firms: (i) acquire information infrequently, generating sticky information (Mankiw and Reis 2002) and (ii) face menu costs, producing state-dependent sticky prices. I estimate parameters via indirect inference and show that under considerable real rigidity, sticky prices in a sticky-information environment are consistent with micro and macro evidence. Sticky prices not only help match micro data on price changes’ size and durations between adjustments; they also improve the model's fit with the macro data, as embodied in an empirical Phillips curve.
ANALYSIS OF DETACHED ECLIPSING BINARIES NEAR THE TURNOFF OF THE OPEN CLUSTER NGC 7142

We analyze extensive BVRCIC photometry and radial velocity measurements for three double-lined deeply eclipsing binary stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 days) detached binary V375 Cep is a high probability cluster member, and has a total eclipse of the secondary star. The characteristics of the primary star (M = 1.288 ± 0.017 M ☉) at the cluster turnoff indicate an age of 3.6 Gyr (with a random uncertainty of 0.25 Gyr), consistent with earlier analysis of the color-magnitude diagram. The secondary star (M = 0.871 ± 0.008 M ☉) is not expected to have evolved significantly, but its radius is more than 10% larger than predicted by models. Because this binary system has a known age, it is useful for testing the idea that radius inflation can occur in short period binaries for stars with significant convective envelopes due to the inhibition of energy transport by magnetic fields. The brighter star in the binary also produces a precision estimate of the distance modulus, independent of reddening estimates: (m – M) V = 12.86 ± 0.07. The other two eclipsing binary systems are not cluster members, although one of the systems (V2) could only be conclusively ruled out as a present or former member once the stellar characteristics were determined. That binary is within 0.°5 of edge-on, is in a fairly long-period eccentric binary, and contains two almost indistinguishable stars. The other binary (V1) has a small but nonzero eccentricity (e = 0.038) in spite of having an orbital period under 5 days.
Non-specific activity of (+/-)CP-96,345 in models of pain and inflammation.

Abstract The non-peptide NK1 receptor antagonist, CP-96,345, and its 2R,3R enantiomer CP-96,344, which is not an NK1 receptor antagonist (IC50 > 10 microM), were evaluated for antinociceptive and anti-inflammatory activities in several classical models of pain and inflammation in the rat. Both CP-96,345 and CP-96,344 reduced carrageenin-induced paw oedema and hyperalgesia, and attenuated the second phase of formalin-induced paw licking with equal potency. These results indicate that NK1 antagonism is not responsible for the activity of (+/-)-CP-96,345 in the above animal models.
On the presumed capture origin of Jupiter's outer satellites

Abstract The problem of the origin of Jupiter's outer satellites is treated within the framework of the theory of capture through collinear libration points. Lower bounds for the satellites' semimajor axes are found from a corrected rederivation of Bailey's capture theory. Upper bounds are found from a new derivation of the stability limit for satellites, based on Floquet stability theory. It is shown that if the bodies had near-zero relative velocity when passing the libration point, direct orbits would lie outside retrograde orbits, which is not the case for Jupiter. It is found that the dimensions and distributions of the direct group are well explained by libration-point capture with Jupiter's mass = 1 1730 solar mass, which is interpreted as indicating capture soon after Jupiter's formation. But ad hoc assumptions are required for this capture model to explain the retrograde group. It is concluded that the direct and retrograde groups may have had different mechanisms of origin.
Mathematical Analysis of Throughput Bounds in Random Access with ZigZag Decoding

We investigate the throughput improvement that ZigZag decoding (Gollakota and Katabi 2008) can achieve in multi-user random access systems. ZigZag is a recently proposed 802.11 receiver design that allows successful reception of packets despite collision. Thus, the maximum achievable throughput of a wireless LAN can be significantly improved by using ZigZag decoding. We analyze the throughput bounds in four different idealized multi-access system models for the case when ZigZag decoding is used. We also provide results for the Aloha and CSMA models where exact closed form solutions are infeasible to calculate. Our analysis and simulation results show that ZigZag decoding can significantly improve the maximum throughput of the random access system.
Abstract Domains of Affine Relations

This article considers some known abstract domains for affine-relation analysis (ARA), along with several variants, and studies how they relate to each other. The various domains represent sets of points that satisfy affine relations over variables that hold machine integers and are based on an extension of linear algebra to modules over a ring (in particular, arithmetic performed modulo 2w, for some machine-integer width w).We show that the abstract domains of Muller-Olm/Seidl (MOS) and King/Sondergaard (KS) are, in general, incomparable. However, we give sound interconversion methods. In other words, we give an algorithm to convert a KS element vKS to an overapproximating MOS element vMOS—that is, γ (vKS) ⊆ γ (vMOS—as well as an algorithm to convert an MOS element wMOS to an overapproximating KS element wKS—that is, γ (wMOS) ⊆ γ (wKS).The article provides insight on the range of options that one has for performing ARA in a program analyzer:—We describe how to perform a greedy, operator-by-operator abstraction method to obtain KS abstract transformers.—We also describe a more global approach to obtaining KS abstract transformers that considers the semantics of an entire instruction, basic block, or other loop-free program fragment.The latter method can yield best abstract transformers, and hence can be more precise than the former method. However, the latter method is more expensive.We also explain how to use the KS domain for interprocedural program analysis using a bit-precise concrete semantics, but without bit blasting.
Chemoselective Oxidation of Sulfides to Sulfones with Magnesium Monoperoxyphthalate (MMPP) On Silica Gel Support in Methylene Chloride Solvent

Abstract A simple, efficient and chemoselective, non-aqueous procedure for oxidation of sulfides to the corresponding sulfones with magnesium monoperoxyphthalate on hydrated silica gel has been developed.
Asymmetric induction in Manganese(III)-based oxidative free-radical cyclizations of chiral esters and amides

Abstract Mn(III)-based oxidative free-radical cyclizations of phenylmenthyl acetoacetate 1d affords 90% of 11 with 86% de. trans-2 -Phenylcyclohexyl ester 1e affords 5e with only 60% de. The 2,5-dimethylpyrrolidine amide 1h affords 14 with higher de (92%), but in only 28% yield.
Extension of the Fenske-Hall Molecular Orbital Approach to Tight-Binding Band Structure Calculations: Bulk and Surface Electronic Structure of MoS2

A new tight-binding band structure calculation method is described. This method, which is based on the Fenske−Hall molecular orbital technique, should be extremely useful in the study of the bulk and surface electronic structure of inorganic materials. The approximations used in the Fenske−Hall method are reviewed, and the extension of this approach to periodic band structure calculations is outlined. Results of calculations for bulk MoS2 are in good agreement with previous experimental and theoretical results. Results of calculations for two-dimensional MoS2 slabs exposing (100) edge planes provide a description of coordinatively unsaturated Mo and S atoms on these edges. Coordinative unsaturation at the Mo atoms introduces new surface states near the Fermi level. Coordinative unsaturation at the S atoms leads to high-energy occupied bands that can be attributed to S lone pair electrons. Surface bonds between Mo atoms and terminal S atoms are stronger than bulk Mo−S bonds, suggesting that terminal S atom...
IS THERE REALLY AN EXPORT WAGE PREMIUM? A CASE STUDY OF LOS ANGELES USING MATCHED EMPLOYEE-EMPLOYER DATA

This paper investigates the effects of exporting on wages, specifically the claim that workers are paid higher wages if they are employed in manufacturing plants that export vis-a-vis plants that do not export. Past research on US plants has supported the existence of an export wage premium, though European studies dispute those results calling for more care in econometric investigation to control for worker characteristics. We answer this call developing a matched employee-employer data set linking worker characteristics from the one-in-six long form of the Decennial Household Census to manufacturing establishment data from the Longitudinal Research Database. Analysis focuses on 1990 and 2000 data for the Los Angeles Consolidated Metropolitan Statistical Area. Our results confirm that the average wage in manufacturing plants that export is greater than that in manufacturing plants that do not export. However, after controlling for worker characteristics such as age, gender, education, race and nationality, the export wage premium vanishes. That is, when comparing workers with similar characteristics, there is no wage difference between exporting and non-exporting plants. These results concord with recent findings from Europe and elsewhere.
Atomistic aspects of diffusion and growth on the Si and Ge (111) surfaces

The stability of interfaces and the mechanisms of thin film growth on semiconductors are issues of central importance in electronic devices. These can only be understood through detailed study of the relevant microscopic processes. Experimental studies are able to provide detailed, atomic-scale information for model systems. Theoretical analysis of experimental results is essential in explaining certain surprising observations and in providing guidance for optimizing conditions and methods of growth. We review recent theoretical work on the diffusion of adatoms, the structure of adsorbate monolayers, and their implications for growth on the Si and Ge (111) surfaces. The theoretical analysis consists of first-principles calculations of the total-energy and entropy factors for stable, metastable and saddle-point configurations. These calculations are supplemented by Monte Carlo simulations of simple models that afford direct contact with experimental observations.
A Bayesian Nonparametric Approach to Image Super-Resolution

Super-resolution methods form high-resolution images from low-resolution images. In this paper, we develop a new Bayesian nonparametric model for super-resolution. Our method uses a beta-Bernoulli process to learn a set of recurring visual patterns, called dictionary elements, from the data. Because it is nonparametric, the number of elements found is also determined from the data. We test the results on both benchmark and natural images, comparing with several other models from the research literature. We perform large-scale human evaluation experiments to assess the visual quality of the results. In a first implementation, we use Gibbs sampling to approximate the posterior. However, this algorithm is not feasible for large-scale data. To circumvent this, we then develop an online variational Bayes (VB) algorithm. This algorithm finds high quality dictionaries in a fraction of the time needed by the Gibbs sampler.
The Role of Investment Banks in Acquisitions

We compare acquisitions completed with and without investment bank advice over the 1981 to 1992 period. We find that the choice to use an investment bank depends on the complexity of the transaction, the type of transaction (takeovers versus acquisitions of assets), the acquiror’s prior acquisition experience, and the degree of diversification of the target firm. Although acquisition announcement returns are lower for firms using investment banks, this difference can be explained by differences in transaction characteristics. These results suggest that transaction costs are the main determinant of investment banking choice, followed by contracting costs and asymmetric information costs.
An alternative measure of structural unemployment

Abstract In this paper we derive an alternative measure for structural unemployment using a stochastic frontier analysis. This measure, by empirical design, is always less than total unemployment and it is, thus, more consistent with the theoretical description of structural unemployment than its usual interpretation as a smoothed long-run average of total unemployment. We find that our measure does not always track the long-run trends in total unemployment in the U.S. and when compared to the existing measures can provide different insights into the evolution of structural unemployment. Demographic and regional evidences offer some validation for our approach and allow us to determine how demographic and regional factors are related to the variation in structural unemployment across time and regions.
Critical Hamiltonians with long range hopping

Critical states are studied by a real space RG in the problem with strong diagonal disorder and long range power law hopping. The RG ow of the distribution of coupling parameters is characterized by a family of non-trivial fix points. We consider the RG flow of the distribution of participation ratios of eigenstates. Scaling of participation ratios is sensitive to the nature of the RG fix point. For some fix points, scaling of participation ratios is characterized by a distribution of exponents, rather than by a single exponent. The RG method can be generalized to treat certain fermionic Hamiltonians with disorder and long range hopping. We derive the RG for a model of interacting two-level systems. Besides couplings, in this problem the RG includes the density of states. The density of states is renormalized so that it develops a singularity near zero energy.
Role of transport in rural development in Africa

Rural Africa is starved of transport services. The transport routes run towards the export enclaves and the coast. The political, social and developmental rural transport benefits are discussed. Rural transport will help (i) integrate the country and ease its governance; (ii) widen markets; (iii) induce increased agricultural output, through new technologies, reduced transport costs, etc. The transport cost savings should be passed on to rural firms and producers. The paper warns against their accruing only to middlemen — agricultural parastatals inclusive, thereby stifling the benefits to production. This could happen under some forms of pan‐territorial pricing. Negative aspects of road development, e.g. the substitution of local goods by imports, increased migration and noise, are noted. The place and role of project appraisal in rural road planning is acknowledged. The broad‐based development packages approach associated with Integrated Rural Development Projects has, despite its attractions, some pitf...
Nuclear plant aging study of Residual Heat Removal systems

The effects of aging on Residual Heat Removal systems in Boiling Water Reactors have been studied as part of the Nuclear Plant Aging Research program. The aging phenomena has been characterized by analyzing operating experience from various national data bases. In addition, actual plant data was obtained to supplement and validate the data base findings. Time-dependent failure rates were calculated for several components to identify aging trends. A computer program was developed and implemented to model a typical RHR system and perform time-dependent Probabilistic Risk Assessment calculations. Using the time-dependent failure rates calculated from the data, the effects of aging on system unavailability and component importance were investigated. 10 refs., 12 figs.
Multidomain multiphase fluid mechanics

Abstract A set of multiphase field equations—conservation of mass, momentum and energy-based on multiphase mechanics is developed. Multiphase mechanics applies to mixtures of phases which are separated by interfaces and are mutually exclusive. This is in contrast to the field equations of mixtures based on continuum mechanics which directly applies to molecular mixtures where the phases coexist at the same points in space. Based on the multiphase mechanics formulation, additional terms appear in the field equations when the physical size of the dispersed phase (bubble or droplet) is many times larger than the inter-molecular spacing:These terms are the' inertial coupling due to virtual mass and the additional viscous coupling due to unsteadiness of the flow field. These physical effects as well as the continuum inertia! coupling terms were neglected in many other two-phase calculations. By including this inertial coupling term, the onedimensional multiphase equations are found to give real characteristics. Furthermore, the sum of momentum equations of all phases reduces to the momentum equations of the mixture as should be expected.
Modular synthesis of biologically active phosphatidic acid probes using click chemistry.

Phosphatidic acid (PA) is an important signaling lipid that plays roles in a range of biological processes including both physiological and pathophysiological events. PA is one of a number of signaling lipids that can act as site-specific ligands for protein receptors in binding events that enforce membrane association and generally regulate both receptor function and subcellular localization. However, elucidation of the full scope of PA activities has proven problematic, primarily due to the lack of a consensus sequence among PA-binding receptors. Thus, experimental approaches, such as those employing lipid probes, are necessary for characterizing interactions at the molecular level. Herein, we describe an efficient modular approach to the synthesis of a range of PA probes that employs a late stage introduction of reporter groups. This strategy was exploited in the synthesis of PA probes bearing fluorescent and photoaffinity tags as well as a bifunctional probe containing both a photoaffinity moiety and an azide as a secondary handle for purification purposes. To discern the ability of these PA analogs to mimic the natural lipid in protein-binding properties, each compound was incorporated into vesicles for binding studies using a known PA receptor, the C2 domain of PKCα. In these studies, each compound exhibited binding properties that were comparable to those of synthetic PA, indicating their viability as probes for effectively studying the activities of PA in cellular processes.
Synthesis and biological activity of new conformationally restricted analogues of pepstatin.

A new statine derivative, 3-hydroxy-4-amino-5-mercaptopentanoic acid; cysteinylstatine (CySta), was synthesized and used to prepare a series of conformationally restricted analogues of pepstatin (Iva-Val-Val-Sta-Ala-Sta) in which the conformational constraint was introduced via a bis-sulfide connecting the appropriately substituted residues in the P1 and the P3 inhibitor side chains. The precursor peptide, Iva-Cys-Val-CySta-Ala-Iaa, was synthesized and alkylated with a series of dibromoalkanes and alkenes to produce the cyclic structures. This strategy permitted the carbon atom spacing between the P1 and the P3 inhibitor side chains to be systematically varied so as to produce inhibitors with 15-, 16-, and 17-membered ring systems. Additional non-cyclic analogues were synthesized as controls by alkylating the bisthiol intermediates with methyl iodide. The inhibitory potency of the analogues were determined against porcine pepsin and penicillopepsin by using standard enzyme kinetic assays. The cyclic inhibitor were found to be potent inhibitors of both aspartic proteases; inhibitor that contained a trans-2-butene link between the two sulfur atoms was found to be the most potent inhibitor with a Ki less than 1 nm against pepsin and 3.94 nm against penicillopepsin. This series of compounds illustrates a new type of conformational restriction that can be used to probe for the bioactive conformation of peptides.