cssi/SciSciGPT-SciSciNet huggingface dataset:
Ice nucleation in internally mixed ammonium sulfate/dicarboxylic acid particles

[1] Recent studies have shown that tropospheric sulfate aerosols commonly contain 50% or more by mass organic species. The influence of these organics on the chemical and physical properties of sulfate aerosols is not fully established. Using an aerosol flow tube technique, we have determined ice nucleation temperatures for particles composed of ammonium sulfate and mixtures of ammonium sulfate with a series of dicarboxylic acids. A calibration curve was developed to allow us to convert the freezing temperatures to a saturation ratio required for ice nucleation. At levels detectable by our experimental technique we find that the freezing temperatures and critical ice saturation ratios of each system were identical, for a given water activity of the solution, even though the solutions contained varying fractions of inorganic and organic components. Further experiments showed that the freezing behavior of pure dicarboxylic acid particles was identical to that of the other systems studied if the water activity was identical. Although the apparent freezing temperatures reported here are substantially warmer than those predicted by the water activity based nucleation theory of T. Koop et al., we find that solution water activity defined the freezing conditions for the systems studied here.
Characterization of novel sulfonium photoacid generators and their microwave-assisted synthesis

Microwave-assisted synthesis of triarylsulfonium salt photoacid generators (PAGs) afforded reaction times 90 to 420 times faster than conventional thermal conditions, with photoacid quantum yields of new sulfonium PAGs ranging from 0.01 to 0.4.
Signal transmission in passive media

Under rather general assumptions, and in a relatively simple and straightforward manner, it is shown that the characteristics of signals which travel through homogeneous, as well as inhomogeneous, passive media have the principal features usually associated with the phenomena of precursors, as generally follows from more elaborate studies. The simplicity of the present arguments permits analytic studies to be made for a greater variety of media than is normally the case.
Shifts in the properties of the Higgs boson from radion mixing

We examine how mixing between the Standard Model Higgs boson, h, and the radion present in the Randall-Sundrum model of localized gravity modifies the expected properties of the Higgs boson. In particular, we demonstrate that the total and partial decay widths of the Higgs, as well as the h→gg branching fraction, can be substantially altered from their Standard Model expectations. The remaining branching fractions are modified less than 5% for most of the parameter space volume.
Stability of influence maximization

The present article serves as an erratum to our paper of the same title, which was presented and published in the KDD 2014 conference. In that article, we claimed falsely that the objective function defined in Section 1.4 is non-monotone submodular. We are deeply indebted to Debmalya Mandal, Jean Pouget-Abadie and Yaron Singer for bringing to our attention a counter-example to that claim.Subsequent to becoming aware of the counter-example, we have shown that the objective function is in fact NP-hard to approximate to within a factor of O(n1-e) for any e > 0.In an attempt to fix the record, the present article combines the problem motivation, models, and experimental results sections from the original incorrect article with the new hardness result. We would like readers to only cite and use this version (which will remain an unpublished note) instead of the incorrect conference version.
Chemical fractionation in the solar system

The cosmochemical and geochemical history of planetary material is reflected in relative and absolute abundances of two groups of trace elements; siderophiles and volatiles. Many of these elements can be determined at the requires levels only by radiochemical neutron activation analysis. The abundance patterns of elements in chondritic meteorites result from condensation processes in the solar nebula. The composition of planetisimals which bombarded the Moon is characterized from trace elements in lunar breccias, and is also related to nebula processes. Trace elements in anorthosites and basalts from Earth and Moon suggest that the Moon is refractory-rich and volatile-poor relative to the Earth.
Fractionalization of interstitials in curved colloidal crystals.

Understanding the consequences of the interplay of defects and local curvature in crystals is far from complete despite the considerable influence that a defect has on the crystal’s local properties. It is now found that interstitials inserted in curved crystals at oil/glycerol interfaces can fractionate into two dislocations, which glide through the lattice in opposite directions until they get absorbed into existing dislocations, scars or pleats.
The Strength of Weak Learnability

This paper addresses the problem of improving the accuracy of an hypothesis output by a learning algorithm in the distribution-free (PAC) learning model. A concept class is learnable (or strongly learnable) if, given access to a source of examples of the unknown concept, the learner with high probability is able to output an hypothesis that is correct on all but an arbitrarily small fraction of the instances. The concept class is weakly learnable if the learner can produce an hypothesis that performs only slightly better than random guessing. In this paper, it is shown that these two notions of learnability are equivalent. A method is described for converting a weak learning algorithm into one that achieves arbitrarily high accuracy. This construction may have practical applications as a tool for efficiently converting a mediocre learning algorithm into one that performs extremely well. In addition, the construction has some interesting theoretical consequences, including a set of general upper bounds on the complexity of any strong learning algorithm as a function of the allowed error e.
Far-Flung Filaments of Ejecta in the Young Supernova Remnant G292.0+1.8

New optical images of the young supernova remnant (SNR) G292.0+1.8, obtained from the 0.9 m telescope at Cerro Tololo Inter-American Observatory, show a more extensive network of filaments than had been known previously. Filaments emitting in [O III] are distributed throughout much of the 8' diameter shell seen in X-ray and radio images, including a few at the very outermost shell limits. In addition to the extensive [O III] filaments, we have detected four small complexes of filaments that show [S II] emission along with the oxygen lines. In a single long-slit spectrum we find variations of almost an order of magnitude in the relative strengths of oxygen and sulfur lines, which must result from abundance variations. None of the filaments, with or without [S II], shows any evidence for hydrogen, so all appear to be fragments of pure supernova ejecta. The [S II] filaments provide the first evidence for undiluted products of oxygen burning in the ejecta from the supernova that gave rise to G292.0+1.8. Some oxygen burning, either hydrostatic or explosive, must have occurred, but the paucity of [S II]-emitting filaments suggests that either the oxygen burning was not extensive or that most of its products have yet to be excited. Most of the outer filaments exhibit radial, pencil-like morphologies that suggest an origin as Rayleigh-Taylor fingers of ejecta, perhaps formed during the explosion. Simulations of core-collapse supernovae predict the development of such fingers, but these have never before been so clearly observed in a young SNR. Following careful subtraction of the stars in the field, we have measured the total flux in [O III] ?5007 as 5.4 ? 10-12 ergs cm-2 s-1. Using a distance of 6 kpc and an extinction correction corresponding to E(B - V) = 0.6 mag (lower than previous values but more consistent both with our data and with X-ray and radio measurements of the hydrogen column density) leads to a luminosity of 1.6 ? 1035 ergs s-1 in the 5007 ? line.
Conversion of α-aminocarboxylic acids to α-aminophosphonic acids

Abstract Naturally occurring α-amino acids may be converted to their phosphonate analogues in good yield by oxidative decarboxylation with lead tetraacetate, followed by reaction with (MeO)3P and TiCl4.
THEORETICAL RADII OF TRANSITING GIANT PLANETS: THE CASE OF OGLE-TR-56b

We calculate radius versus age trajectories for the photometrically selected transiting extrasolar giant planet, OGLE-TR-56b, and find agreement between theory and observation, without introducing an ad hoc extra source of heat in its core. The fact that the radius of HD 209458b seems larger than the radii of the recently discovered OGLE family of extremely close-in transiting planets suggests that HD 209458b is anomalous. Nevertheless, our good fit to OGLE-TR-56b bolsters the notion that the generic dependence of transit radii on stellar irradiation, mass, and age is, to within error bars, now quantitatively understood.
Impact of sensor detection limits on protecting water distribution systems from contamination events

Real-time water quality sensors are becoming commonplace in water distribution systems. However, field deployable, contaminant-specific sensors are still in the development stage. As development proceeds, the necessary operating parameters of these sensors must be determined to protect consumers from accidental and malevolent contamination events. This objective can be quantified in several different ways including minimization of: the time necessary to detect a contamination event, the population exposed to contaminated water, the extent of the contamination within the network, and others. We examine the ability of a sensor set to meet these objectives as a function of both the detection limit of the sensors and the number of sensors in the network. A moderately sized distribution network is used as an example and different sized sets of randomly placed sensors are considered. For each combination of a certain number of sensors and a detection limit, the mean values of the different objectives across multiple random sensor placements are calculated. The tradeoff between the necessary detection limit in a sensor and the number of sensors is evaluated. Results show that for the example problem examined here, a sensor detection limit of 0.01 of the average source concentration is adequate for maximum protection. Detection of events is dependent on the detection limit of the sensors, but for those events that are detected, the values of the performance measures are not a function of the sensor detection limit. The results of replacing a single sensor in a network with a sensor having a much lower detection limit show that while this replacement can improve results, the majority of the additional events detected had performance measures of relatively low consequence.
On parity conservation and neutrino mass

1. YANG and LEE(') have recently suggested that present experimental evidence does not exclude the possibility that parity is not conserved in (3-decay. If future experiments confirm this, it may be possible to relate parity-violation in neutrino-decays to the vanishing of neutrino mass and self-mass. The argument is as follows : the free neutrino Lagrangian is invariant for the substitution gyp, -.yip, (V. -* V,y5). If it is further postulated that neutrino interactions produce no self-mass, one way to secure this is to require that the total. Lagrangian also remain invariant for the same substitution (2) (so that -► w, ,) while other fields (barring degeneracies which we consider later) remain unchanged. In so far as +V, and ytV, have opposite intrinsic parity, most neutrino interactions would then violate parity conservation.
Catalyst precursors for the catalytic Pauson-Khand reaction

Dicobalt hexacarbonyl complexes of enynes serve as Co2(CO)8 surrogates for the intramolecular Pauson-Khand cycloaddition. Enynes with polar functional groups allow for easy separation of the catalyst cyclopentenone by-product (acid or base wash, silica gel plug column) from the desired cyclopentenone.
An Empirical Analysis of Digital Music Bundling Strategies

We use panel data on digital song and album sales coupled with a quasi-random price experiment to determine own-and cross-price elasticities for songs and albums. We then develop a structural model of consumer demand to estimate welfare under various policy relevant counterfactual scenarios. This approach represents an early application of the “big data” management paradigm within the media industries and provides managers with detailed guidance on optimal pricing and marketing strategies for digital music. Our results show that tiered pricing coupled with reduced album pricing increases revenue to the labels by 18% relative to uniform pricing policies traditionally preferred by digital marketplaces while also increasing consumer surplus by 23%. Thus, optimal tiered pricing can yield a Pareto improvement over the prior status quo. Additionally, our results indicate that even without tiered pricing, unbundling albums outperforms “album-only” pricing policies that dominated the era of physical CD/cassette sales. This paper was accepted by Alok Gupta, special issue on business analytics.
Creative Destruction: Barriers to Urban Growth and the Great Boston Fire of 1872

Urban growth requires the replacement of outdated buildings, yet growth may be restricted when landowners do not internalize positive spillover effects from their own reconstruction. The Boston Fire of 1872 created an opportunity for widespread simultaneous reconstruction, initiating a virtuous circle in which building upgrades encouraged further upgrades of nearby buildings. Land values increased substantially among burned plots and nearby unburned plots, capitalizing economic gains comparable to the prior value of burned buildings. Boston had grown rapidly prior to the Fire, but negative spillovers from outdated durable buildings had substantially constrained its growth by dampening reconstruction incentives.
High performance robust motion control of machine tools: an adaptive robust control approach and comparative experiments

Studies the high performance robust motion control of machine tools. Instead of the disturbance observer (DOB) design previously tested by many researchers, a newly proposed adaptive robust control (ARC) is applied to make the resulting closed-loop system robust to model uncertainties. Compared to DOB, the proposed ARC has a better tracking performance and transient in the presence of discontinuous disturbances such as Coulomb friction and it is of a lower-order. As a result, time-consuming and costly rigorous friction identification and compensation is alleviated and overall tracking performance is improved. The ARC design can also handle large parameter variations and is flexible in introducing extra nonlinear robust control terms and parameter adaptations to further improve the transient response and tracking performance. An anti-integration windup mechanism is built in the ARC and thus the problem of control saturation is alleviated. Extensive comparative experimental tests are performed and the results show the superior performance of the proposed ARC.
Finding the elusive balance between reducing fatigue and enhancing education: perspectives from American residents.

Duty hour restrictions for residency training were implemented in the United States to improve residents’ educational experience and quality of life, as well as to improve patient care and safety; however, these restrictions are by no means problem-free. In this paper, we discuss the positive and negative aspects of duty hour restrictions, briefly highlighting research on the impact of reduced duty hours and the experiences of American residents. We also consider whether certain specialties (e.g., Emergency Medicine, Radiology) may be more amenable than others (e.g., Surgery) to duty hour restrictions. We conclude that feedback from residents is a crucial element that must be considered in any future attempts to strike a balance between reducing fatigue and enhancing education.
Production economics: Worthwhile investment?

Abstract Agricultural production economics research is examined within a broad framework of scientific development and utilization. Recent findings in selected areas of the subdiscipline are examined and opportunities for further fruitful inquiry are identified. A few ‘stylized facts’ emerge from recent work and suggest the need for much careful hypothesis testing, model exploration, and empirical sensitivity analysis in the future.
Embeddings of homogeneous spaces into irreducible modules

Abstract Let G be a connected reductive algebraic group. We find a necessary and sufficient condition for a quasi-affine homogeneous space G / H to have an embedding into an irreducible G-module. For reductive H we also find a necessary and sufficient condition for a closed embedding of G / H into an irreducible module to exist. These conditions are stated in terms of the group of central automorphisms of G / H .
On CAPM and Black–Scholes differing risk-return strategies

Abstract In their path-finding 1973 paper, Black and Scholes presented two separate derivations of their famous option pricing partial differential equation. The second derivation was from the standpoint that was Black's original motivation, namely, the capital asset pricing model (CAPM). We show here, in contrast, that the option valuation is not uniquely determined; in particular, strategies based on the delta-hedge and CAPM provide different valuations of an option although both hedges are instantaneouly riskfree. Second, we show explicitly that CAPM is not, as economists claim, an equilibrium theory.
Advances in Coupled Geomechanical and Reservoir Modeling With Applications to Reservoir Compaction

Coupled geomechanical and reservoir modeling is becoming feasible on a full field scale. This paper describes the advances of the coupled model described previously, its extensions for modeling compaction and the application of the model in full field studies. The advances of the theory and numerical implementation since the original work make it practical to perform full field coupled studies with complex, realistic description of the geomechanical behaviour of the reservoir and shales, which allows prediction of stress changes, reservoir compaction and surface subsidence. These capabilities are demonstrated in field examples that analyze and predict classical pressure induced compaction in a gas field as well as thermally induced compaction in a heavy oil field. In both cases the methodology of interpreting the geomechanical laboratory and field data and its integration in the coupled modeling process was the key to obtaining a realistic predictive tool. The examples demonstrate that the technology is maturing to the point that conventional studies can be converted to coupled modeling on a fairly routine basis.
New advances in three‐dimensional controlled‐source electromagnetic inversion

SUMMARY New techniques for improving both the computational and imaging performance of the three-dimensional (3-D) electromagnetic inverse problem are presented. A non-linear conjugate gradient algorithm is the framework of the inversion scheme. Full wave equation modelling for controlled sources is utilized for data simulation along with an efficient gradient computation approach for the model update. Improving the modelling efficiency of the 3-D finite difference (FD) method involves the separation of the potentially large modelling mesh, defining the set of model parameters, from the computational FD meshes used for field simulation. Grid spacings and thus overall grid sizes can be reduced and optimized according to source frequencies and source–receiver offsets of a given input data set. Further computational efficiency is obtained by combining different levels of parallelization. While the parallel scheme allows for an arbitrarily large number of parallel tasks, the relative amount of message passing is kept constant. Image enhancement is achieved by model parameter transformation functions, which enforce bounded conductivity parameters and thus prevent parameter overshoots. Further, a remedy for treating distorted data within the inversion process is presented. Data distortions simulated here include positioning errors and a highly conductive overburden, hiding the desired target signal. The methods are demonstrated using both synthetic and field data.
Inferior Oblique Surgery for Restrictive Strabismus in Patients with Thyroid Orbitopathy

Introduction Thyroid orbitopathy is the most common cause of restrictive strabismus. Patients often present with vertical or horizontal double vision, or both, due to restriction involving most commonly the inferior and medial rectus muscles. Traditional muscle surgery involves release of the tight muscles. Previous literature has described a frequent need for secondary operations and an overcorrection incidence of up to 50%. Recognizing that the tight muscles are also limited in their excursion, it was proposed that operating on the better-moving eye, particularly the inferior oblique, might produce an improvement in binocularity and decrease the incidence of overcorrection. Methods A total of 37 patients with restrictive strabismus due to thyroid orbitopathy treated at the University of Virginia over 12 years with inferior oblique surgery were retrospectively reviewed. Results Eight patients were treated with a combination of inferior oblique surgery and horizontal muscle surgery at the same time. One patient was treated with simultaneous inferior oblique and superior rectus surgery. Seven patients had vertical correction with inferior oblique surgery alone. Twenty-three patients required secondary procedures. Eight patients were overcorrected but only one following primary surgery. At the time of last follow-up, ranging from 6 months to 8 years, 33 patients had no diplopia, 2 had minimal diplopia, and 2 had persistent diplopia. All but two were completely functional. Conclusion Inferior oblique surgery by balancing the overall excursion of extraocular muscles in thyroid patients may produce binocularity in primary position and down reading gaze. The amount of vertical correction from inferior oblique surgery alone is limited, often requiring ipsilateral superior or contralateral inferior rectus surgery. Inferior oblique surgery likely increases the area of binocular single vision and decreases the incidence of overcorrection. The use of Hess screen and binocular single vision fields is helpful in assessment and planning of surgery in these patients.
Synergistic TLBs for High Performance Address Translation in Chip Multiprocessors

Translation Look-aside Buffers (TLBs) are vital hardware support for virtual memory management in high performance computer systems and have a momentous influence on overall system performance. Numerous techniques to reduce TLB miss latencies including the impact of TLB size, associativity, multilevel hierarchies, super pages, and prefetching have been well studied in the context of uniprocessors. However, with Chip Multiprocessors (CMPs) becoming the standard design point of processor architectures, it is imperative that we review the design and organization of TLBs in the context of CMPs. In this paper, we propose to improve system performance by means of a novel way of organizing TLBs called Synergistic TLBs. Synergistic TLB is different from per-core private TLB organization in three ways: (i) it provides capacity sharing of TLBs by facilitating storing of victim translations from one TLB in another to emulate a distributed shared TLB (DST), (ii) it supports translation migration for maximizing the utilization of TLB capacity, and (iii) it supports translation replication to avoid excess latency for remote TLB accesses. We explore all the design points in this design space and find that an optimal point exists for high performance address translation. Our evaluation with both multiprogrammed (SPEC 2006 applications) and multithreaded workloads (PARSEC applications) shows that Synergistic TLBs can eliminate, respectively, 44.3% and 31.2% of the TLB misses, on average. It also improves the weighted speedup of multiprogrammed application mixes by 25.1% and performance of multithreaded applications by 27.3%, on average.
The use of DBT skills in the treatment of difficult patients in the General Hospital

Received Sept. 19, 2002; revision received Feb. 24, 2003; acceptedMarch 17, 2003. From the Psychiatry Consultation Service, Massachusetts General Hospital; and the Harvard Medical School, Boston. Address reprint requests to Dr. Huffman, Massachusetts General Hospital, 55 Fruit St., Warren 605, Boston, MA 02114; jhuffman@partners.org (e-mail). Copyright 2003 The Academy of Psychosomatic Medicine. Dialectical behavior therapy (DBT) is a form of psychotherapy developed by Marsha Linehan in the 1980s to treat borderline personality disorder. Subsequent studies have found that DBT leads to less self-injury, fewer inpatient hospitalizations, and improved social adjustment in psychiatric outpatients with borderline personality disorder and also leads to less self-injury, depression, and anxiety among psychiatric inpatients with borderline personality disorder. Critical reviews of this literature have noted that these studies are limited by small numbers of subjects (less than 25 subjects in the active treatment groups), by the lack of a control group in the inpatient study, and by the fact that much of this research has been done by a single research group (led by Linehan). Despite these flaws, the studies do suggest that DBT can have a significant impact on psychiatric symptoms and quality of life for persons with borderline personality disorder. DBT relies upon principles of both cognitive behavior therapy and Eastern meditative philosophy to help patients with borderline personality disorder regulate their emotions. The treatment assumes that maladaptive behaviors, including self-injury, are attempts to manage intense affect. DBT emphasizes validation of a patient’s painful emotional experience and acceptance that the patient is doing the best that he or she can at that moment. DBT also emphasizes the need for change by teaching new coping skills. The skills training component of this treatment modality focuses on development of skills in four areas: mindfulness, interpersonal effectiveness, distress tolerance, and emotion regulation. While DBT has effectively treated individuals with borderline personality disorder in psychiatric settings, it appears that specific DBT skills could be adaptable to the treatment of difficult patients in the general hospital. Such skills can be introduced to help patients on medical units cope more effectively with stressful experiences. These skills can also be taught to staff to help them regulate their own emotional reactions to difficult patients. Here we present the hypothetical case of a patient on a medical service whose interpersonal style led to difficulties in management. Following the case vignette, we discuss how the principles of DBT and the skills that it teaches can be applied to medical patients in the general hospital.
On stabbing queries for generalized longest repeat

A longest repeat query on a string, motivated by its applications in many subfields including computational biology, asks for the longest repetitive substring(s) covering a particular string position (point query). In this paper, we extend the longest repeat query from point query to interval query, allowing the search for longest repeat(s) covering any position interval, and thus significantly improve the usability of the solution. Our method for interval query takes a different approach using the insight from a recent work on shortest unique substrings [1], as the prior work's approach for point query becomes infeasible in the setting of interval query. Using the critical insight from [1], we propose an indexing structure, which can be constructed in the optimal O(n) time and space for a string of size n, such that any future interval query can be answered in O(1) time. Further, our solution can find all longest repeats covering any given interval using optimal O(occ) time, where occ is the number of longest repeats covering that given interval, whereas the prior O(n)-time and space work can find only one candidate for each point query. Experiments with real-world biological data show that our proposal is competitive with prior works, both time and space wise, while providing with the new functionality of interval queries as opposed to point queries provided by prior works.
Rapid Flow-Based Peptide Synthesis

A flow-based solid-phase peptide synthesis methodology that enables the incorporation of an amino acid residue every 1.8 min under automatic control or every 3 min under manual control is described. This is accomplished by passing a stream of reagent through a heat exchanger into a low volume, low backpressure reaction vessel, and through a UV detector. These features enable continuous delivery of heated solvents and reagents to the solid support at high flow rate, thereby maintaining maximal concentration of reagents in the reaction vessel, quickly exchanging reagents, and eliminating the need to rapidly heat reagents after they have been added to the vessel. The UV detector enables continuous monitoring of the process. To demonstrate the broad applicability and reliability of this method, it was employed in the total synthesis of a small protein, as well as dozens of peptides. The quality of the material obtained with this method is comparable to that for traditional batch methods, and, in all cases, the desired material was readily purifiable by RP-HPLC. The application of this method to the synthesis of the 113-residue Bacillus amyloliquefaciens RNase and the 130-residue DARPin pE59 is described in the accompanying manuscript.
The Rate of Return to the High/Scope Perry Preschool Program.

Abstract This paper estimates the rate of return to the HighScope Perry Preschool Program, an early intervention program targeted toward disadvantaged African-American youth. Estimates of the rate of return to the Perry program are widely cited to support the claim of substantial economic benefits from preschool education programs. Previous studies of the rate of return to this program ignore the compromises that occurred in the randomization protocol. They do not report standard errors. The rates of return estimated in this paper account for these factors. We conduct an extensive analysis of sensitivity to alternative plausible assumptions. Estimated annual social rates of return generally fall between 7 and 10%, with most estimates substantially lower than those previously reported in the literature. However, returns are generally statistically significantly different from zero for both males and females and are above the historical return on equity. Estimated benefit-to-cost ratios support this conclusion.
Distributed code assignments for CDMA packet radio networks

Code-division multi-access (CDMA) techniques allow many users to transmit simultaneously in the same band without substantial interference by using approximately orthogonal (low cross-correlation) spread-spectrum waveforms. Two-phase algorithms have been devised to assign and reassign spread-spectrum codes to transmitters, to receivers and to pairs of stations in a large dynamic packet radio network in polynomial times. The purpose of the code assignments is to spatially reuse spreading codes to reduce the possibility of packet collisions and to react dynamically to topological changes. These two-phase algorithms minimize the time complexity in the first phase and minimize the number of control packets needed to be exchanged in the second phase. Therefore, they can start the network operation in a short time, then switch to the second phase with the goal of adapting to topological changes. A pairwise code-assignment scheme is proposed to assign codes to edges. Simulations based on well-controlled topologies (sparse topologies) show that the scheme requires much fewer codes than transmitter-based code assignment, while maintaining similar throughput performance. >
Structure of Three-Dimensional Separated Flow on an Axisymmetric Bump

Fine-spatial-resolution laser Doppler velocimeter measurements were obtained on one-half of the leeside of an axisymmetric bump in a turbulent boundary layer. The ratio of bump height H and boundary-layer thickness 6 is HIS = 2. Three-dimensional separations occur on the leeside with one saddle separation on the centerline that is connected with a separation line to one focus separation on each side. Downstream of the saddle point the mean backflow converges to the focal separation points in a region confined within about 0.156 from the local bump surface. The mean backflow zone is supplied by the intermittent large eddies as well as by the near surface flow from the side of the bump. The separated flow has a higher turbulent kinetic energy and shows bimodal histograms in local U and W, which appear to be due to highly unsteady low-frequency meandering motions. Because of the variation of the mean flow angle in the separation zones, the turbulent flow from different directions is decorrelated, resulting in lower Reynolds shearing stresses. Farther from the wall, large streamwise vortices form from flow around the sides of the bump.
Vertical Directionality of Midfrequency Surface Noise in Downward-Refracting Environments

The vertical directionality of ambient noise due to surface agitation for frequencies between 2 and 5 kHz propagated to a subsurface receiver has a characteristic shape, knowledge of which may enhance shallow-water operations. In general, the noise level is highest at upward-looking angles and attenuated at downward-looking angles depending on the nature of the bottom. In environments with a negative profile gradient, the noise level is also greatly reduced in a low-angle shadow zone or "notch" at angles around horizontal. This paper reviews the character of vertical noise directionality by examining two measured data sets and considering the underlying physical mechanisms that drive the form of the distribution. A discussion of the implications of vertical noise directionality for design and operation of receiving sonar systems is presented. In particular, the effect of mainlobe beamwidth and sidelobe suppression are considered along with the directionality of the noise field. Finally, an overview of the derivation of a vertical noise model based on the integrated mode method of propagation prediction is followed by model reproduction of measurements.
Predictors of reexcision findings and recurrence after breast conservation.

Abstract Purpose To identify predictors of reexcision findings and local recurrence in the setting of breast-conserving therapy with radiation. Methods The records of 535 patients who underwent breast-conserving surgery followed by radiation for Stage I or II cancer between 1972 and 1996 were reviewed. The mean follow-up period for surviving patients without evidence of recurrence is 6 years. Various clinical and pathologic prognostic factors were examined for significance with regard to reexcision findings and recurrence rates. Pathologic margin status was classified as negative, close (≤2 mm), positive, or indeterminate. Results The pathologic margin status was the most important predictor of local recurrence. The freedom from local relapse (FFLR) at 6 years was 97% for patients with negative pathologic margins and 86% for all others ( p p = 0.0001) and young patient age ( p = 0.03) were predictive of residual disease in the specimen. Patients with initially close margins and no EIC had a low risk of residual disease at the time of reexcision, as did patients older than age 65 without EIC. Conclusion Pathologic margin status is the most important predictor of local recurrence after breast conservation with radiation. Patient age and EIC were significant predictors of residual disease at reexcision. The use and timing of systemic therapy appear to influence the risk of local recurrence in patients who do not have negative lumpectomy margins.
Metric-space analysis of spike trains: theory, algorithms and application

We present the mathematical basis of a new approach to the analysis of temporal coding. The foundation of the approach is the construction of several families of novel distances (metrics) between neuronal impulse trains. In contrast to most previous approaches to the analysis of temporal coding, the present approach does not attempt to embed impulse trains in a vector space, and does not assume a Euclidean notion of distance. Rather, the proposed metrics formalize physiologically based hypotheses for those aspects of the firing pattern that might be stimulus dependent, and make essential use of the point-process nature of neural discharges. We show that these families of metrics endow the space of impulse trains with related but inequivalent topological structures. We demonstrate how these metrics can be used to determine whether a set of observed responses has a stimulus-dependent temporal structure without a vector-space embedding. We show how multidimensional scaling can be used to assess the similarity of these metrics to Euclidean distances. For two of these families of metrics (one based on spike times and one based on spike intervals), we present highly efficient computational algorithms for calculating the distances. We illustrate these ideas by application to artificial data sets and to recordings from auditory and visual cortex.
Development of new plasmid DNA vaccine vectors with R1-based replicons

There has been renewed interest in biopharmaceuticals based on plasmid DNA (pDNA) in recent years due to the approval of several veterinary DNA vaccines, on-going clinical trials of human pDNA-based therapies, and significant advances in adjuvants and delivery vehicles that have helped overcome earlier efficacy deficits. With this interest comes the need for high-yield, cost-effective manufacturing processes. To this end, vector engineering is one promising strategy to improve plasmid production. In this work, we have constructed a new DNA vaccine vector, pDMB02-GFP, containing the runaway R1 origin of replication. The runaway replication phenotype should result in plasmid copy number amplification after a temperature shift from 30°C to 42°C. However, using Escherichia coli DH5α as a host, we observed that the highest yields of pDMB02-GFP were achieved during constant-temperature culture at 30°C, with a maximum yield of approximately 19 mg pDNA/g DCW being observed. By measuring mRNA and protein levels of the R1 replication initiator protein, RepA, we determined that RepA may be limiting pDMB02-GFP yield at 42°C. A mutant plasmid, pDMB-ATG, was constructed by changing the repA start codon from the sub-optimal GTG to ATG. In cultures of DH5α[pDMB-ATG], temperature-induced plasmid amplification was more dramatic than that observed with pDMB02-GFP, and RepA protein was detectable for several hours longer than in cultures of pDMB02-GFP at 42°C. Overall, we have demonstrated that R1-based plasmids can produce high yields of high-quality pDNA without the need for a temperature shift, and have laid the groundwork for further investigation of this class of vectors in the context of plasmid DNA production.
Motivations Behind Donors' Contributions to Crowdfunded Journalism

Crowdfunded journalism is a new model for funding journalism in which reporters solicit micropayments from readers to finance their reporting. In the present study, we seek to identify the major motivations behind readers' donations to a pioneering crowdfunded journalism website, Spot.Us. Under the theoretical framework of collective action, we explore a total of 9 motivations: altruism, fun, belief in freedom of content, social, community, self-esteem, understanding, image, and family and friends. Combining self-reported survey data (N = 344) with behavioral data on readers' complete donation records obtained from the Spot.Us server, we found that belief in freedom of content, altruism, and contributing to one's community were self-reported to be highly valued by donors, but fun and family and friends motivations were the only positive predictors for actual donation levels. We discuss the implications of these findings on the sustainability of crowdfunding as a business model for news.
Cognitive Behavior Therapy for PTSD in Rape Survivors

In recent years, new data have appeared, further suggesting the utility of cognitive-behavioral interventions for posttraumatic stress disorder (PTSD) subsequent to sexual assault. In this article, we present a model of cognitive-behavioral treatment (CBT) for PTSD in rape survivors. Emotional-processing theory, which proposes mechanisms that underlie the development of disturbances following rape, is reviewed. A CBT-based therapy (Prolonged Exposure) is presented that entails education about common reactions to trauma, relaxation training, imaginal reliving of the rape memory, exposure to trauma reminders, and cognitive restructuring. Current research regarding the use of prolonged exposure is discussed. The case example of a young female rape survivor is described in detail, and her prior substance dependence and intense shame are highlighted. The therapy was successful in reducing the client's symptoms of PTSD, as well as her depressive symptoms, and these gains were maintained at a one-year follow-up assessment.
PEGylated Inorganic Nanoparticles

Application of inorganic nanoparticles in diagnosis and therapy has become a critical component in the targeted treatment of diseases. The surface modification of inorganic oxides is important for providing diversity in size, shape, solubility, long-term stability, and attachment of selective functional groups. This Minireview describes the role of polyethylene glycol (PEG) in the surface modification of oxides and focuses on their biomedical applications. Such a PEGylation of surfaces provides "stealth" characteristics to nanomaterials otherwise identified as foreign materials by human body. The role of PEG as structure-directing agent in synthesis of oxides is also presented.
An Isothermal Titration Calorimetry Study on the Binding of Four Volatile General Anesthetics to the Hydrophobic Core of a Four-α-Helix Bundle Protein

A molecular understanding of volatile anesthetic mechanisms of action will require structural descriptions of anesthetic-protein complexes. Previous work has demonstrated that the halogenated alkane volatile anesthetics halothane and chloroform bind to the hydrophobic core of the four-alpha-helix bundle (Aalpha(2)-L38M)(2) (Johansson et al., 2000, 2003). This study shows that the halogenated ether anesthetics isoflurane, sevoflurane, and enflurane are also bound to the hydrophobic core of the four-alpha-helix bundle, using isothermal titration calorimetry. Isoflurane and sevoflurane both bound to the four-alpha-helix bundle with K(d) values of 140 +/- 10 micro M, whereas enflurane bound with a K(d) value of 240 +/- 10 micro M. The DeltaH degrees values associated with isoflurane, sevoflurane, and enflurane binding were -7.7 +/- 0.1 kcal/mol, -8.2 +/- 0.2 kcal/mol, and -7.2 +/- 0.1 kcal/mol, respectively. The DeltaS degrees values accompanying isoflurane, sevoflurane, and enflurane binding were -8.5 cal/mol K, -10.4 cal/mol K, and -8.0 cal/mol K, respectively. The results indicate that the hydrophobic core of (Aalpha(2)-L38M)(2) is able to accommodate three modern ether anesthetics with K(d) values that approximate their clinical EC(50) values. The DeltaH degrees values point to the importance of polar interactions for volatile general anesthetic binding, and suggest that hydrogen bonding to the ether oxygens may be operative.
Practical threshold signatures

We present an RSA threshold signature scheme. The scheme enjoys the following properties: 1. it is unforgeable and robust in the random oracle model, assuming the RSA problem is hard; 2. signature share generation and verification is completely non-interactive; 3. the size of an individual signature share is bounded by a constant times the size of the RSA modulus.
Universal Outlier Hypothesis Testing

Outlier hypothesis testing is studied in a universal setting. Multiple sequences of observations are collected, a small subset of which are outliers. A sequence is considered an outlier if the observations in that sequence are distributed according to an outlier distribution, distinct from the typical distribution governing the observations in all the other sequences. Nothing is known about the outlier and typical distributions except that they are distinct and have full supports. The goal is to design a universal test to best discern the outlier sequence(s). For models with exactly one outlier sequence, the generalized likelihood test is shown to be universally exponentially consistent. A single-letter characterization of the error exponent achievable by the test is derived, and it is shown that the test achieves the optimal error exponent asymptotically as the number of sequences approaches infinity. When the null hypothesis with no outlier is included, a modification of the generalized likelihood test is shown to achieve the same error exponent under each non-null hypothesis, and also consistency under the null hypothesis. Then, models with more than one outlier are studied in the following settings. For the setting with a known number of distinctly distributed outliers, the achievable error exponent of the generalized likelihood test is characterized. The limiting error exponent achieved by such a test is characterized, and the test is shown to be asymptotically exponentially consistent. For the setting with an unknown number of identically distributed outliers, a modification of the generalized likelihood test is shown to achieve a positive error exponent under each non-null hypothesis, and also consistency under the null hypothesis. When the outlier sequences can be distinctly distributed (with their total number being unknown), it is shown that a universally exponentially consistent test cannot exist, even when the typical distribution is known and the null hypothesis is excluded.
Experimental Simulation of Parametric Instabilities in Laser-Plasma Interactions

Abstract : There is currently a great interest in the mechanisms by which intense electromagnetic radiation interacts with plasmas. A major impetus for this interest has been the laser-pellet fusion program. The process whereby the incident electromagnetic wave gives up energy to the plasma can be much more complex than simple binary collisional damping by electronion collisions. (Author)
High spectral resolution multiplex CARS spectroscopy using chirped pulses

Abstract A simple technique for achieving high spectral resolution coherent anti-Stokes Raman scattering (CARS) spectra with a femtosecond laser system is presented. A linearly chirped and stretched (∼10 ps) pump pulse generates CARS signal only when overlapped in time with the Stokes pulse (90 fs), creating a `temporal slit' that defines the spectral resolution of the technique. Multiplex CARS spectra for liquid methanol and liquid isooctane are presented, demonstrating a spectral resolution of better than 5 cm −1 . This new chirped (c-CARS) technique should prove useful for chemically-selective imaging applications, as it significantly reduces the non-resonant background contribution.