cssi/SciSciGPT-SciSciNet huggingface dataset:
Nanogenerators and Nanopiezotronics

Developing novel technologies for wireless nanodevices and nanosystems is of critical importance for in-situ, realtime and implantable biosensing, biomedical monitoring and biodetection. It is highly desired for wireless devices and even required for implanted biomedical devices to be self-powered without the use of a battery. Therefore, it is essential to explore innovative nanotechnologies for converting mechanical energy (such as body movement, muscle stretching), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as body fluid and blood flow) into electrical energy that can be used to power nanodevices. We have demonstrated an innovative approach for converting nano-scale mechanical energy into electrical energy using piezoelectric zinc oxide nanowire (NW) arrays. We have recently developed a DC nanogenerator driven by an ultrasonic wave. This represents a tremendous step towards realization of practical piezoelectric based nanogenerators. The mechanism of operation of the electric generator relies on the unique coupling of piezoelectric and semiconducting properties of ZnO as well as the elegant rectifying function of the Schottky barrier formed between a metal tip and the NW. Based on this principle, piezoelectric-field effect transistors, gated diodes, sensors and resonators have been fabricated. These form the fundamental components of nano-piezotronics. Piezotronics is the field of using coupled piezoelectric-semiconducting properties for fabricating novel and unique electronic devices and components.
Stereoselection in the Prins-pinacol synthesis of acyltetrahydrofurans.

Depending upon the nature of the alkene and allylic substituents, acid-promoted rearrangements of acetals derived from anti allylic diols give 12 or stereoisomeric acyltetrahydrofurans 13. Stereoelectronic effects of the allylic substituents and the extent of bonding in the Prins cyclization transition state are central features of a proposed new model for predicting stereoselection in the Prins-pinacol synthesis of acyltetrahydrofurans.
Can baryogenesis occur on the lattice

We examine the question of how baryogenesis can occur in lattice models of the Standard Model where there is a global U (1) symmetry which is accompanied by an exactly conserved fermion number. We demonstrate that fermion creation and annihilation can occur in these models despite this exact fermion number conservation, by explicitly computing the spectral flow of the hamiltonian in the two dimensional U(1) axial model with Wilson fermions. For comparison we also study the closely related Schwinger model where a similar mechanism gives rise to anomalous particle creation and annihilation.
Crystal growth, structure, polarization, and magnetic properties of cesium vanadate, Cs2V3O8: a structure-property study.

Cesium vanadate, Cs2V3O8, a member of the fresnoite-type structure, was synthesized via a hydrothermal route and structurally characterized by single-crystal X-ray diffraction. Cs2V3O8 crystallizes in a noncentrosymmetric polar space group, P4bm, with crystal data of a = 8.9448(4) A, c = 6.0032(3) A, V = 480.31(4) A3, and Z = 2. The material exhibits a two-dimensional layered crystal structure consisting of corner-shared V5+O4 and V4+O5 polyhedra. The layers are separated by the cesium cations. The alignment of the individual polyhedra results in a macroscopic polarity for Cs2V3O8. Frequency-dependent polarization measurements indicate that the material is not ferroelectric. A pyroelectric coefficient of −2.0 μC m–2 K–1 was obtained from pyroelectric measurements taken as a function of the temperature. The magnetic susceptibility data were measured as a function of the temperature and yielded an effective magnetic moment of 1.78 μB for the V4+ cation. Short-range magnetic ordering was observed around 7 K....
Anti-Self-Dual Instantons with Lagrangian Boundary Conditions II: Bubbling

We study bubbling phenomena of anti-self-dual instantons on Open image in new window where Σ is a closed Riemann surface. The instantons satisfy a global Lagrangian boundary condition on each boundary slice Open image in new window . The main results establish the energy quantization and removal of singularities near such boundary slices. This completes the analytic foundations for the definition of a new instanton Floer homology for 3-manifolds with boundary. In the interior case, for anti-self-instantons on Open image in new window our methods provide a new approach to the removable singularity theorem by Sibner-Sibner for codimension 2 singularities with a holonomy condition.
Androgen regulation of RNA synthesis in target tissues.

Abstract The increased rate of protein synthesis induced in the prostate and seminal vesicle by the injection of dihydrotestosterone is preceded by an increased synthesis of RNA and is blocked by inhibitors such as actinomycin D. This increased protein synthesis can also be induced by administering into the lumen of the seminal vesicle RNA extracted from the seminal vesicle of an androgen-treated rat. When the RNA is placed on a Sepharose 4B polyuridylic acid column or a cellulose polythymidylic acid column, a small fraction of the RNA is tightly bound. The unbound RNA is eluted with buffer and subsequently the bound RNA is eluted with a more alkaline buffer. The injection of dihydrotestosterone in vivo greatly increases the incorporation of cytidine into this bound RNA. The bound poly (A)-rich RNA, presumably polyadenylic acid RNA, from the seminal vesicles of androgen treated males resulted in increased protein synthesis when instilled into the seminal vesicle of castrate males. In contrast, the unbound RNA from the seminal vesicle was ineffective when instilled into the seminal vesicles of castrate rats.
Competitive investment in clean technology and uninformed green consumers

Abstract In a market where consumers and the regulatory authorities are not fully informed about the actual production technology or environmental performance of firms that engage in strategic competition, I study the effect of environmental consciousness of consumers on firms׳ incentive to invest in cleaner technology. Firms compete in prices and may signal their environmental performance to uninformed consumers through prices. I also analyze the effect of an expected liability on firms in this setting. Compared to full information, incomplete information generates higher strategic incentive to invest in cleaner technology particularly when consciousness and/or expected liability are not too high. Requiring mandatory disclosure of technology or environmental performance may discourage such investment. Even though consumers and the regulator are uninformed, competition has a positive effect (relative to monopoly) on the incentive to invest.
Brownian Motion of a Massive Binary

The dynamical friction and diffusion coefficients are derived for a massive binary that moves against a uniform background of stars. The random impulses exerted on the binary's center of mass by the field stars are greater than those exerted on a point particle due to inelastic scattering. The frictional force acting on the binary is less than that acting on a point particle due to randomization of the trajectories of field stars that pass near the binary. Both effects tend to increase the random motion of a binary compared with that of a point mass. If the maximum effective impact parameter for gravitational encounters is comparable to the radius of gravitational influence of the binary, its Brownian velocity can be increased by a modest factor (2) compared with that of a single particle. This condition is probably fulfilled in the case of binary supermassive black holes in galactic nuclei.
Parallel branch and bound algorithm for computing maximal structured singular value

In the paper, a parallel branch and bound algorithm has been developed, which computes the maximal structured singular value μ without tightly bounding μ for each frequency, and thus significantly reducing the computational complexity.
Improving the hydrodynamic performance of diffuser vanes via shape optimization

The performance of a diffuser in a pump stage depends on its configuration and placement within the stage. The influence of vane shape on the hydrodynamic performance of a diffuser has been studied. The goal of this effort has been to improve the performance of a pump stage by optimizing the shape of the diffuser vanes. The shape of the vanes was defined using Bezier curves and circular arcs. Surrogate model based tools were used to identify regions of the vane that have a strong influence on its performance. Optimization of the vane shape, in the absence of manufacturing and stress constraints, led to a nearly 8% reduction in the total pressure losses compared to the baseline design by reducing the base separation.
The effect of workload on the performance and availability of voting algorithms

Voting algorithms are a popular way to provide data consistency in replicated data systems. By maintaining multiple copies of data on distinct servers, they can increase the data's availability, as perceived by a user. Many models have been made to study the degree to which replication increases the availability of data, and some have been made to study the cost incurred in maintaining consistency. However, little work has been done to evaluate the time it takes to serve a request, accounting for server and network failures, or to determine the effect of workload on these measures. The effect of workload can be significant, since failures of system components are not important unless they are needed to deliver a service, and requests can force updates on data that would otherwise be outdated. In this paper, we use stochastic activity networks (SANs), a variant of stochastic Petri nets, to construct two variant models of a replicated file system, one using a static voting algorithm while the other using a dynamic voting algorithm to maintain data consistency. A Markov process representation is automatically constructed from each SAN model and is solved numerically. Specifically, we determine the availability and mean time to respond to write requests as a function of the number of replicated copies and workload offered to the system. The results illustrate that it is indeed possible to determine such measures analytically and that workload, as well as the number of copies, is an important determinant of availability and response time.
Potent inhibition of serine proteases by heterocyclic sulfide derivatives of 1,2,5-thiadiazolidin-3-one 1,1 dioxide.

Abstract The existence of subtle differences in the S n ′ subsites of closely-related (chymo)trypsin-like serine proteases, and the fact that the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold docks to the active site of (chymo)trypsin-like enzymes in a substrate-like fashion, suggested that the introduction of recognition elements that can potentially interact with the S n ′ subsites of these proteases might provide an effective means for optimizing enzyme potency and selectivity. Accordingly, a series of heterocyclic sulfide derivatives based on the 1,2,5-thiadiazolidin-3-one 1,1 dioxide scaffold (I) was synthesized and the inhibitory activity and selectivity of these compounds toward human leukocyte elastase (HLE), proteinase 3 (PR 3) and cathepsin G (Cat G) were then determined. Compounds with P 1 =isobutyl were found to be potent, time-dependent inhibitors of HLE and, to a lesser extent PR 3, while those with P 1 =benzyl inactivated Cat G rapidly and irreversibly. This study has demonstrated that 1,2,5-thiadiazolidin-3-one 1,1 dioxide-based heterocyclic sulfides are effective inhibitors of (chymo)trypsin-like serine proteases.
Measuring the Force Ejecting DNA from Phage

We discuss how a balance can be established between the force acting to eject DNA from viral capsids and the force resisting its entry into a colloidal suspension that mimics the host cell cytoplasm. The ejection force arises from the energy stored in the capsid as a consequence of the viral genome (double-stranded DNA) being strongly bent and crowded on itself. The resisting force is associated with the osmotic pressure exerted by the colloidal particles in the host solution. Indeed, recent experimental work has demonstrated that the extent of ejection can be progressively limited by increasing the external osmotic pressure; at a sufficiently high pressure, the ejection is completely suppressed. We outline here a theoretical analysis that allows a determination of the internal (capsid) pressure by examining the different relations between force and pressure inside and outside the capsid using the experimentally measured position of the force balance.
Maximizing network utilization with max---min fairness in wireless sensor networks

The state-of-the-art for optimal data-gathering in wireless sensor networks is to use additive increase algorithms to achieve fair rate allocation while implicity trying to maximize network utilization. For the quantification of the problem we present a receiver capacity model to capture the interference existing in a wireless network. We also provide empirical evidence to motivate the applicability of this model to a real CSMA based wireless network. Using this model, we explicitly formulate the problem of maximizing the network utilization subject to a max---min fair rate allocation constraint in the form of two coupled linear programs. We first show how the max---min rate can be computed efficiently for a given network. We then adopt a dual-based approach to maximize the network utilization. The analysis of the dual shows the sub-optimality of previously proposed additive increase algorithms with respect to bandwidth efficiency. Although in theory a dual-based sub-gradient search algorithm can take a long time to converge, we find empirically that setting all shadow prices to an equal and small constant value, results in near-optimal solutions within one iteration (within 2% of the optimum in 99.65% of the cases). This results in a fast heuristic distributed algorithm that has a nice intuitive explanation--rates are allocated sequentially after rank ordering flows based on the number of downstream receivers whose bandwidth they consume. We also investigate the near optimal performance of this heuristic by comparing the rank ordering of the source rates obtained from the heuristic to the solutions obtained by solving the linear program.
Can the acceleration of our universe be explained by the effects of inhomogeneities

No, it is simply not plausible that cosmic acceleration could arise within the context of general relativity from a back-reaction effect of inhomogeneities in our universe, without the presence of a cosmological constant or 'dark energy'. We point out that our universe appears to be described very accurately on all scales by a Newtonianly perturbed FLRW metric. (This assertion is entirely consistent with the fact that we commonly encounter δρ/ρ > 1030.) If the universe is accurately described by a Newtonianly perturbed FLRW metric, then the back-reaction of inhomogeneities on the dynamics of the universe is negligible. If not, then it is the burden of an alternative model to account for the observed properties of our universe. We emphasize with concrete examples that it is not adequate to attempt to justify a model by merely showing that some spatially averaged quantities behave the same way as in FLRW models with acceleration. A quantity representing the 'scale factor' may 'accelerate' without there being any physically observable consequences of this acceleration. It also is not adequate to calculate the second-order stress–energy tensor and show that it has a form similar to that of a cosmological constant of the appropriate magnitude. The second-order stress–energy tensor is gauge dependent, and if it were large, contributions of higher perturbative order could not be neglected. We attempt to clear up the apparent confusion between the second-order stress–energy tensor arising in perturbation theory and the 'effective stress–energy tensor' arising in the 'shortwave approximation'.
Bureaucratic Control and the Soft Budget Constraint

Abstract In the hierarchy of China's state sector, both before and during the current reform period, government bureaucrats select and supervise state-owned enterprise (SOE) managers. The incentive problem of SOE managers has been studied carefully, but that of the bureaucrats has not. This paper uses a model to show that the agency problem of the bureaucrat leads to the persistence of the soft-budget constraint (SBC) in the state sector. This suggests that the problem of SBC is unlikely to go away even when other familiar reasons contributing to the SBC disappear, e.g., concern about employment. J. Comp. Econom., March 1998, 26(1), pp. 41–61. Bolton College, Chestnut Hill, Massachusetts 02167; and Industrial Relations Center, Carlson School of Management, University of Minnesota, Minneapolis, Minnesota 55455.
THREE MODELS FOR THE HOMOTOPY THEORY OF HOMOTOPY THEORIES

Abstract Given any model category, or more generally any category with weak equivalences, its simplicial localization is a simplicial category which can rightfully be called the “homotopy theory” of the model category. There is a model category structure on the category of simplicial categories, so taking its simplicial localization yields a “homotopy theory of homotopy theories”. In this paper we show that there are two different categories of diagrams of simplicial sets, each equipped with an appropriate definition of weak equivalence, such that the resulting homotopy theories are each equivalent to the homotopy theory arising from the model category structure on simplicial categories. Thus, any of these three categories with the respective weak equivalences could be considered a model for the homotopy theory of homotopy theories. One of them in particular, Rezk’s complete Segal space model category structure on the category of simplicial spaces, is much more convenient from the perspective of making calculations and therefore obtaining information about a given homotopy theory.
The Motor Rewind Issue-A New Look

Motor users have always been concerned about how long a rewound motor would last but never knew what to do about it. As power costs become higher and higher, a new and related question is cost. What happens to the efficiency and operating cost of a motor that is rewound two to three tithes during, its lifetime? The answers will depend upon how the motor is repaired. How motor losses can be changed during the rewind process is reviewed, along with what precautions should be taken to prevent an increase in operating costs and a decrease in motor life. The positive steps the motor user can take to protect his motor investment will also be explored.
Erosion of circumstellar particle disks by interstellar dust

Circumstellar particle disks appear to be a common phenomenon; however, their properties vary greatly. Models of the evolution of such systems focus on internal mechanisms such as interparticle collisions and Poynting-Robertson drag. Herein it is shown that 'sandblasting' by interstellar dust can be an important and even dominant contributor to the evolution of circumstellar particle disks. Stars spend up to about 3 percent of their main-sequence lifetimes within atomic clouds. Among an IRAS sample of 21 nearby main-sequence A stars, beta Pictoris has the brightest disk; it also possesses the smallest random velocity and therefore the slowest predicted erosion rate.
Reduction of α,β-unsaturated nitroalkenes with borane and borohydrides. A convenient route to 3-nitro-, 3-hydroxylamino-, and 3-amino-2h-1-benzopyran derivatives

The borohydride catalyzed borane reduction of 3-nitrochromenes provided a facile route to a variety of 3-hydroxylamino- 5 and 3-amino-2H-1-benzopyranes 6. Reduction with methoxyborohydride species, on the other hand, provided 3-nitrochromans 2,4.
A Quantum Theory of Optical Dispersion.

When a theory is framed trying to explain a discrepant system of facts, it is a necessary process of thought to take some branch of the theory as more completely true than the rest, and to adjust the remaining parts in such a way that they will fit in with this base, though they may still conflict with one another. This has certainly been true of the quantum theory; the speculations connected with it have as their base the law of the conservation of energy. Now a critical examination of fundamentals does not by any means justify this faith. It is of course a fact of observation that in the gross energy is conserved, but this only means an averaged energy; and as pure dynamics has failed to explain many atomic phenomena there seems no reason to maintain the exact conservation of energy, which is only one of the consequences of the dynamical equations. Indeed it is hardly too much to say that had the photoelectric effect been discovered a century ago, it is probable that no one would ever have suggested that the status of the first law of thermodynamics was in any way different from that of the second. On the other hand, Bohr's theory, and especially Sommerfeld's extension of it, have given great encouragement to the belief that in dynamics lay the way to the complete truth, so that in consequence of the triumphs of that theory there has been little thought in other directions. Another impediment is that our whole ideas are saturated with the principles of energy, so that denying it leaves hardly any foundation from which to start.
The Impact of Local Sales Tax on the Value of Owner-Occupied Housing

Abstract Local governments are under pressure to develop alternative revenue sources to their property tax bases. Among their responses has been an increased reliance on local sales taxes. This study examines the impact of local sales taxes on the value of owner-occupied housing in the Phoenix metropolitan area. The results indicate that differences in local sales tax rates across jurisdictions are capitalized into residential property values in the same way as differences in property tax rates, albeit to a lesser extent because part of the sales tax burden can be exported to nonresidents.
Physician Prescribing of Sterile Injection Equipment To Prevent HIV Infection: Time for Action

Physicians and pharmacists can play an important role in providing syringe access by prescribing and dispensing syringes to patients who use injection drugs and cannot or will not enter drug treatment.
Serologic evidence of active Epstein-Barr virus infection in Epstein-Barr virus-associated lymphoproliferative disorders of children with acquired immunodeficiency syndrome.

The DNA and nuclear antigens of Epstein-Barr virus (EBV) have been detected in specimens of tissue of non-Hodgkin lymphoma and lymphocytic interstitial pneumonitis from patients with acquired immunodeficiency syndrome. To determine whether there is serologic evidence of an active EBV infection in these disorders, we conducted a case-control study. The case patients were 10 children with acquired immunodeficiency syndrome and EBV genome-positive pneumonitis or lymphoma. We randomly selected one or, if available, two matched control patients with human immunodeficiency virus infection for each index patient and compared their EBV serologic profiles with those of the index case patient at the time of the biopsy. Ten case patients and 13 matched control patients were enrolled. All 10 case patients (100%) compared with 2 (15%) of 13 matched control patients had serologic evidence of either a primary or a reactivated EBV infection at the time the index patient had a biopsy performed ( p
Physical Properties of Metals from a Renormalization Group Standpoint

We derive the equilibrium and transport properties of metals using renormalization group equations and finite-size scaling. Particular attention is given to the well-known cases of Fermi and Luttinger liquids. An important subtlety is that the temperature dependence of many transport coefficients is determined by "dangerous" irrelevant operators. We also characterize violations of Fermi or Luttinger liquid behavior in terms of indices, analogous to the critical indices describing phase transitions. We briefly consider the normal-state properties of the cuprates from this standpoint.
The demand for punishment

Abstract While many experiments demonstrate that behavior differs from the predictions of traditional economic theory, they have not shown that economic reasoning is necessarily incorrect. Instead, these experiments illustrate that the preferences of homo economicus have been mis-specified. Modeled with social preferences, it may be rational for agents to forego material gains. Social dilemmas are examples in which punishment is not credible and yet people often pay to reprimand other participants. At the same time, we show that these people also react to changes in the price of punishing and income as if punishment was an ordinary and inferior good.
Comparison of Doppler US and CT Angiography for Evaluation of Renal Artery Stenosis

Rationale and Objectives. The authors compared Doppler ultrasound (US) with computed tomographic (CT) angiography in the evaluation of stenosis of the main renal artery. Materials and Methods. Fifty-six patients who had undergone conventional angiography of the renal arteries participated in a prospective comparison of Doppler US (45 patients) and CT angiography (52 patients). US evaluation included both the main renal artery and segmental renal arteries. Results. There were 27 main renal arteries with at least 50% stenosis in 20 patients. In 36 patients, there was no significant stenosis. All cases of main renal artery stenosis detected with Doppler US of the segmental arteries were also identified with Doppler US of the main renal artery. The by-artery sensitivity (63%) of US of the main renal artery was greater than that (33%) of US of the segmental arteries. CT angiography was more sensitive (96%) than Doppler US (63%) in the detection of stenosis, but the specificity of CT (88%) was similar to that of US (89%). The difference in the area under the receiver operating characteristic curve (AUC) between CT (AUC = 0.94) and US (AUC = 0.82) was statistically significant (P = .038). Conclusion. Doppler US of the main renal artery is more sensitive than Doppler US of segmental arteries in the detection of stenosis. CT angiography is more accurate than Doppler US in the evaluation of renal artery stenosis.
Universality of the Volume Bound in Slow-Roll Eternal Inflation

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e{sup S{sub dS}/2} without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where the probability to produce infinite volume becomes non zero. We show that the bound holds sharply also in any space-time dimensions, when arbitrary higher-dimensional operators are included and in the multi-field inflationary case. The relation with the entropy of de Sitter and the universality of the bound strengthen the case for a deeper holographic interpretation. As a spin-off we provide the formalism to compute the probability distribution of the volume after inflation for generic multi-field models, which might help to address questions about the population of vacua of the landscape during slow-roll inflation.
Static shear stress of electrorheological fluids.

We have calculated the static shear stress of an induced electrorheological solid for a single-chain structure, double-chain structure, triple-chain structure, and body-centered tetragonal (bct) lattice. When the shear strain is small, all of these four structures prefer slanted configurations which will come back to the original configurations if the load is removed. As the shear strain exceeds a yield point, the structures break into parts which cannot return to the original configurations in a short time. The bct lattice is found to have the strongest shear modulus. The triple-chain structure is weaker than the bct lattice, but much stronger than the single-chain structure and double-chain structure. The single-chain structure has the Peierls-Landau instability if the chain is very long. A double chain is stronger than a single chain if the chains are quite long and the situation is reversed if the chains are short.
On the Reliability of Cross‐Correlation Function Lag Determinations in Active Galactic Nuclei

Many active galactic nuclei (AGNs) exhibit a highly variable luminosity. Some AGNs also show a pronounced time delay between variations seen in their optical continuum and in their emission lines. In effect, the emission lines are light echoes of the continuum. This light-travel time delay provides a characteristic radius of the region producing the emission lines. The cross-correlation function (CCF) is the standard tool used to measure the time lag between the continuum and line variations. For the few well-sampled AGNs, the lag is ~1-100 days, depending upon which line is used and the luminosity of the AGN. In the best sampled AGN, NGC 5548, the Hβ lag shows year-to-year changes, ranging from ~8.7 to ~22.9 days over a span of 8 years. In this paper it is demonstrated that, in the context of AGN variability studies, the lag estimate using the CCF is biased too low and subject to a large variance. Thus the year-to-year changes of the measured lag in NGC 5548 do not necessarily imply changes in the AGN structure. The bias and large variance are consequences of finite-duration sampling and the dominance of long timescale trends in the light curves, not of noise or irregular sampling. Lag estimates can be substantially improved by removing low-frequency power from the light curves prior to computing the CCF.
Information Processing in Convex Operational Theories

In order to understand the source and extent of the greater-than-classical information processing power of quantum systems, one wants to characterize both classical and quantum mechanics as points in a broader space of possible theories. One approach to doing this, pioneered by Abramsky and Coecke, is to abstract the essential categorical features of classical and quantum mechanics that support various information-theoretic constraints and possibilities, e.g., the impossibility of cloning in the latter, and the possibility of teleportation in both. Another approach, pursued by the authors and various collaborators, is to begin with a very conservative, and in a sense very concrete, generalization of classical probability theory - which is still sufficient to encompass quantum theory - and to ask which ''quantum'' informational phenomena can be reproduced in this much looser setting. In this paper, we review the progress to date in this second programme, and offer some suggestions as to how to link it with the categorical semantics for quantum processes offered by Abramsky and Coecke.
Copper Delivery by Metallochaperone Proteins

Copper is an essential element in all living organisms, serving as a cofactor for many important proteins and enzymes. Metallochaperone proteins deliver copper ions to specific physiological partners by direct protein-protein interactions. The Atx1-like chaperones transfer copper to intracellular copper transporters, and the CCS chaperones shuttle copper to copper,zinc superoxide dismutase. Crystallographic studies of these two copper chaperone families have provided insights into metal binding and target recognition by metallochaperones and have led to detailed molecular models for the copper transfer mechanism.
Quantum state tomography of slow and stored light

Quantum information can be transferred from a beam of light to a cloud of atoms and controllably released at a later time. This process forms the basis of many important quantum memory devices that are fundamental to the future of quantum information science, quantum computing, and quantum communication. Prior experiments have stored light in a variety of systems, including cold atom clouds, warm atomic vapor, solid state materials, and optical fibers. To extend these successful investigations, the goal of our research program is to carry out a full characterization of the quantum states of stored-and-retrieved multimode light.
A Change Would Do You Good .... An Experimental Study on How to Overcome Coordination Failure in Organizations

Trabajo publicado como articulo en American Economic Review 96(3): 669- 693 (2006).-- http://dx.doi.org/10.1257/aer.96.3.669
Chandra Observations and Models of the Mixed-Morphology Supernova Remnant W44: Global Trends

We report on the Chandra observations of the archetypical mixed morphology (or thermal composite) supernova remnant, W44. As with other mixed morphology remnants, W44's projected center is bright in thermal X-rays. It has an obvious radio shell, but no discernable X-ray shell. In addition, X-ray bright knots dot W44's image. The spectral analysis of the Chandra data show that the remnant s hot, bright projected center is metal-rich and that the bright knots are regions of comparatively elevated elemental abundances. Neon is among the affected elements, suggesting that ejecta contributes to the abundance trends. Furthermore, some of the emitting iron atoms appear to be underionized with respect to the other ions, providing the first potential X-ray evidence for dust destruction in a supernova remnant. We use the Chandra data to test the following explanations for W44's X-ray bright center: 1.) entropy mixing due to bulk mixing or thermal conduction, 2.) evaporation of swept up clouds, and 3.) a metallicity gradient, possibly due to dust destruction and ejecta enrichment. In these tests, we assume that the remnant has evolved beyond the adiabatic evolutionary stage, which explains the X-ray dimness of the shell. The entropy mixed model spectrum was tested against the Chandra spectrum for the remnant's projected center and found to be a good match. The evaporating clouds model was constrained by the finding that the ionization parameters of the bright knots are similar to those of the surrounding regions. While both the entropy mixed and the evaporating clouds models are known to predict centrally bright X-ray morphologies, their predictions fall short of the observed brightness gradient. The resulting brightness gap can be largely filled in by emission from the extra metals in and near the remnant's projected center. The preponderance of evidence (including that drawn from other studies) suggests that W44's remarkable morphology can be attributed to dust destruction and ejecta enrichment within an entropy mixed, adiabatic phase supernova remnant. The Chandra data prompts a new question - by what astrophysical mechanisms are the metals distributed so inhomogeneously in the supernova remnant.
Decreased activation of inflammatory networks during acute asthma exacerbations is associated with chronic airflow obstruction

Asthma exacerbations are associated with subsequent deficits in lung function. Here, we tested the hypothesis that a specific pattern of inflammatory responses during acute exacerbations may be associated with chronic airway obstruction. Gene coexpression networks were characterized in induced sputum obtained during an acute exacerbation, from asthmatic children with or without chronic airflow limitation. The data showed that activation of Th1-like/cytotoxic and interferon signaling pathways during acute exacerbations was decreased in asthmatic children with deficits in baseline lung function. These associations were independent of the identification of picornaviruses in nasal secretions or the use of medications at the time of the exacerbation. Th2-related pathways were also detected in the responses, but variations in these pathways were not related to chronic airways obstruction. Our findings show that decreased activation of Th1-like/cytotoxic and interferon pathways is a hallmark of acute exacerbation responses in asthmatic children with evidence of chronic airways obstruction.
From Denial to Reluctant Dialogue: The Chilean Military's Confrontation with Human Rights (1990–2006)

1 This article analyzes the advances and limitations of transitional justice efforts in democratic Chile through the examination of a key political actor: the armed forces. The military's earlier attitude of denial and noncooperation regarding the human rights violations of the Pinochet dictatorship (1973-1990) was slowly replaced by dialogue with civilians, institutional recognition of violations and limited cooperation with courts. While strategic interactions with other political actors and generational/personnel change stand out as variables explaining the military's behavioral and ideational transformation, the article highlights a crucial third factor: the pluralization of truth and justice mechanisms, both domestic and overseas, that opened up juridical, political and societal fields of contestation against impunity and amnesia. None of Chile's major political actors, including the military, could exert full control over these multiple channels of truth and justice, and the result was the adoption of new strategies and legitimizing discourses more in line with the human rights norm. The military reoriented its stance on human rights in the context of Pinochet's arrest in London in 1998, a changing political environment and the judicial battle over amnesties for the dictatorship's abuses.
Reuse of off-the-shelf components in C2-style architectures

Reuse of large-grain software components offers the potential for significant savings in application development cost and time. Successful component reuse and substitutability depends both on qualities of the components reused as well as the software context in which the reuse is attempted. Disciplined approaches to the structure and design of software applications offers the potential of providing a hospitable setting for such reuse. We present the results of a series of exercises designed to determine how well “offthe-shelf” components could be reused in applications designed in accordance with the C2 software architectural style. The exercises involved the reuse of two user-interface constraint solvers, two graphics toolkits, a World Wide Web browser, and a persistent object manager. A subset of these components was used to construct numerous variations of a single application (thus an application family). The exercises also included construction of a simple development environment for locating and downloading a component off the Web and incorporating it into an application. The paper summarizes the style rules that facilitate reuse and presents the results from the exercises. The exercises were successful in a variety of dimensions; one conclusion is that the C2 style offers significant reuse potential to application developers. At the same time, wider trials and additional tool support are needed.1 Index Terms -software reuse, architectural styles, messagebased architectures, component-based development, graphical user interfaces (GUI).
Visual working memory represents a fixed number of items regardless of complexity

Does visual working memory represent a fixed number of objects, or is capacity reduced as object complexity increases? We measured accuracy in detecting changes between sample and test displays and found that capacity estimates dropped as complexity increased. However, these apparent capacity reductions were strongly correlated with increases in sample-test similarity (r= .97), raising the possibility that change detection was limited by errors in comparing the sample and test, rather than by the number of items that were maintained in working memory. Accordingly, when sample-test similarity was low, capacity estimates for even the most complex objects were equivalent to the estimate for the simplest objects (r= .88), suggesting that visual working memory represents a fixed number of items regardless of complexity. Finally, a correlational analysis suggested a two-factor model of working memory ability, in which the number and resolution of representations in working memory correspond to distinct dimensions of memory ability.
Biological Consequences of Tightly Bent DNA: The Other Life of a Macromolecular Celebrity

The mechanical properties of DNA play a critical role in many biological functions. For example, DNA packing in viruses involves confining the viral genome in a volume (the viral capsid) with dimensions that are comparable to the DNA persistence length. Similarly, eukaryotic DNA is packed in DNA-protein complexes (nucleosomes), in which DNA is tightly bent around protein spools. DNA is also tightly bent by many proteins that regulate transcription, resulting in a variation in gene expression that is amenable to quantitative analysis. In these cases, DNA loops are formed with lengths that are comparable to or smaller than the DNA persistence length. The aim of this review is to describe the physical forces associated with tightly bent DNA in all of these settings and to explore the biological consequences of such bending, as increasingly accessible by single-molecule techniques.
Efficient iterative processing in the SciDB parallel array engine

Many scientific data-intensive applications perform iterative computations on array data. There exist multiple engines specialized for array processing. These engines efficiently support various types of operations, but none includes native support for iterative processing. In this paper, we develop a model for iterative array computations and a series of optimizations. We evaluate the benefits of an optimized, native support for iterative array processing on the SciDB engine and real workloads from the astronomy domain.
Fault tolerant parallel data-intensive algorithms

Fault-tolerance is rapidly becoming a crucial issue in high-end and distributed computing, as increasing number of cores are decreasing the mean-time to failure of the systems. While checkpointing, including checkpointing of parallel programs like MPI applications, provides a general solution, the overhead of this approach is becoming increasingly unacceptable. Thus, algorithm-based fault-tolerance provides a nice practical alternative, though it is less general. Although this approach has been studied for many applications, there is no existing work for algorithm-based fault-tolerance for the growing class of data-intensive parallel applications. In this paper, we present an algorithm-based fault tolerance solution that handles fail-stop failures for a class of data intensive algorithms. We divide the dataset into smaller data blocks and in replication step, we distribute the replicated blocks with the aim of keeping the maximum data intersection between any two processors minimum. This allows us to have minimum data loss when multiple failures occur. In addition, our approach enables better load balance after failure, and decreases the amount of re-processing of the lost data. We have evaluated our approach by using two popular parallel data mining algorithms, which are k-means and apriori. We show that our approach has negligible overhead when there are no failures, and allows us to gracefully handle different number of failures, and failures at different points of processing. We also provide the comparison of our approach with the MapReduce based solution for fault tolerance, and show that we outperform Hadoop both in absence and presence of failures.
An Intrinsic Characterization of Bonnet Surfaces Based on a Closed Differential Ideal

The structure equations for a two-dimensional manifold are introduced and two results based on the Codazzi equations pertinent to the study of isometric surfaces are obtained from them. Important theorems pertaining to isometric surfaces are stated and a theorem due to Bonnet is obtained. A transformation for the connection forms is developed. It is proved that the angle of deformation must be harmonic, and that the differentials of many of the important variables generate a closed differential ideal. This implies that a coordinate system exists in which many of the variables satisfy particular ordinary differential equations, and these results can be used to characterize Bonnet surfaces.
Cardiologist Adapts to Healthcare Change for the Year 2000 The Herrick Lecture

Cardiology as a medical discipline has reached a critical stretch of white water unlike any it has navigated over the past 40 years. The changes our specialty now faces have been brought about not, as in the past, by conceptual or technical advances but rather by cost barriers that will govern every aspect of our work, including education, research, and clinical practice, for as long as anyone can predict. A little more than 40 years ago, when I first entered Dr. Lewis Dexter's laboratory as a cardiology fellow at Harvard Medical School and the Peter Bent Brigham Hospital, cardiac catheterization had been in use for only about 3 or 4 years. It dominated our work in unraveling the questions of circulatory physiology and biochemistry. Shortly thereafter, we began to focus on how the heart functions both as a muscle and as a pump. That was an era of both technological innovation and conceptual advancement best exemplified by new, accurate radiographic imaging techniques. These methods augmented and complemented the physiological pressure-flow measurements and revolutionized the field. They showed us the cardiac chambers and the coronary and other arteries in ways never before possible, thus refining the concept and role of cardiovascular dimension and volume in heart function. All of this culminated in the 1980s with the advent of focused intervention and remarkably effective surgery. Molecular biology, which now dominates academic cardiology, was beginning to find its place in the field. We now have unique drugs for clinical care, and large clinical trials have become commonplace (Fig 1⇓). Figure 1. Until recently, the development of cardiology has been influenced more by conceptual and technological advances than by other forces, but in the 1990s cost has become the chief governing factor and is likely to remain so for as long as anyone can …
Induction-motor stator and rotor winding temperature estimation using signal injection method

A new method to estimate the induction-motor stator and rotor resistance (Rs and Rr) and temperature (Ts and Tr) was proposed in this paper. Two signals with proper frequencies that yield high sensitivities of the terminal measurement to Rs and Rr at a given rotor speed are injected to the induction machine to estimate Rs and R r. The estimated Rs and Rr are then used to estimate Ts and Tr, respectively, according to the relationships between Rs and Ts, and Rr and Tr. Simulation and experimental work have been carried out to verify the proposed method. The proposed method can estimate both stator and rotor resistance and temperature with high accuracy, and the estimated Rs and Rr can be updated in real time. It does not require an additional hardware or a large amount of finite-element analysis (FEA) or experimental data for implementation
Linear and Nonlinear Theory of Eigenfunction Scars

Abstract The theory of scarring of eigenfunctions of classically chaotic systems by short periodic orbits is extended in several ways. The influence of short-time linear recurrences on correlations and fluctuations at long times is emphasized. We include the contribution to scarring of nonlinear recurrences associated with homoclinic orbits and treat the different scenarios of random and nonrandom long-time recurrences. The importance of the local classical structure around the periodic orbit is emphasized, and it is shown for an optimal choice of test basis in phase space that scars must persist in the semiclassical limit. The crucial role of symmetry is also discussed which, together with the nonlinear recurrences gives a much improved account of the actual strength of scars for given classical orbits and in individual wave- functions. Quantitative measures of scarring are provided and comparisons are made with numerical data.