Miracle-dz/UniFAR-FTUs huggingface dataset:
What When Space Matters Little For Firm Productivity? A multilevel analysis of localised knowledge externalities

This paper contributes to the debate on localized knowledge externalities as potential source for firm productivity gains. We apply multilevel analysis to link firm productivity (and growth) to knowledge intensive spatial contexts in the Netherlands. If localized knowledge externalities are important, then firms are hypothesised to co-locate in order to capitalize on each other's knowledge stocks. We conceptualise the regional knowledge base by three dimensions: local 'research and development' intensity, local 'innovativeness', and the characterization of locations by a ‘knowledge workers’ dimension (based on ICT use, educational level, communicative and creative skills). Controlling for firm's heterogeneity, we find a relatively small spatial effect: regional characteristics contribute for only a few percents to firm productivity. The regional intensity of 'innovation' most significantly contributes to this effect. We do not find a contextual spatial effect for productivity growth. These results suggest that the territorial dimension of knowledge externalities should not be exaggerated.
Intra-Amygdala Blockade of the NR2B Subunit of the NMDA Receptor Disrupts the Acquisition But Not the Expression of Fear Conditioning

The lateral nucleus of the amygdala (LA) is an essential component of the neural circuitry underlying Pavlovian fear conditioning. Although blockade of NMDA receptors in LA and adjacent areas before training disrupts the acquisition of fear conditioning, blockade before testing also often disrupts the expression of fear responses. With this pattern of results, it is not possible to distinguish a contribution of NMDA receptors to plasticity from a role in synaptic transmission. In past studies, NMDA blockade has been achieved using the antagonistd,l-2-amino-5-phosphovalerate, which blocks the entire heteromeric receptor complex. The present experiments examined the effects of selective blockade of the NR2B subunit of the NMDA receptor in LA using the selective antagonist ifenprodil. Systemic injections of ifenprodil before training led to a dose-dependent impairment in the acquisition of auditory and contextual fear conditioning, whereas injections before testing had no effect. Intra-amygdala infusions of ifenprodil mirrored these results and, in addition, showed that the effects are attributable to a disruption of fear learning rather than a disruption of memory consolidation. NMDA receptors in LA are thus involved in fear conditioning, and the NR2B subunit appears to make unique contributions to the underlying plasticity.
An Experimental Study of Stall Hysteresis of a Low-Reynolds-Number Airfoil

An experimental study was conducted to investigate static stall hysteresis of a NASA GA(W)-1 airfoil at the chord Reynolds number of Re = 162,000. In addition to mapping the surface pressure distribution around the airfoil, a digital PIV system was used to make detailed flowfield measurements to quantify the occurrence and behavior of laminar boundary layer separation and transition on the airfoil when static stall hysteresis occurs. The measurement results revealed clearly that, for a same angle of attack in the hysteresis loop, incoming flow streams were found to be able to attach to the airfoil upper surface in general with a thin separation bubble formed near the airfoil leading edge when the angle is at the increasing branch of the hysteresis loop. The attached flow pattern resulted in higher lift and lower drag acting on the airfoil as well as a lower Reynolds stress level and smaller unsteadiness in the wake of the airfoil. When the angle of attack is at the decreasing branch of the hysteresis loop, the laminar boundary layer was found to separate from the airfoil upper surface for good at a location very near to the airfoil leading edge. The turbulence transition of the separated laminar boundary layer was found to take place rapidly accompanied by periodical shedding of strong Kelvin-Helmholtz vortex structures in the wake of the airfoil. Large-scale flow separation was found to take place on almost the entire upper surface of the airfoil. As a result, the lower lift and higher drag acting on the airfoil were found with Reynolds stress and turbulence kinetic energy levels in the wake of the airfoil increased significantly. The present study elucidates quantitatively that static stall hysteresis of a low-Reynolds number airfoil is closely related to the behavior of laminar boundary layer separation and transition on the airfoil. The ability of the flow to remember its past history is responsible for the stall hysteretic behavior.
Morphology and Charge Transport in Conjugated Polymers

Determining the relationship between charge transport and morphology is key to increasing the charge carrier mobility of conjugated polymers. This review details a fundamental study of the charge transport and morphology of regioregular poly(3‐hexylthiophene) and sets out general principles for obtaining high charge carrier mobilities. The basis for this study was the finding that despite being more crystalline, low molecular weight films have a substantially lower mobility than high‐MW films. An examination of this apparent contradiction is used to provide insight into how the charge carriers move through a conjugated polymer film and provide a model for charge transport.
Nominal Income Targeting vs Strict Inflation Targeting: A Comparison. By

This paper shows that the instability of nominal income targeting in a simple backward-looking macro model disappears if the policymaker chooses to adopt a hybrid nominal income target. This form of nominal income targeting is compared to a strict inflation target so as to establish the conditions under which the former strategy is preferable to the latter. We derive a U-shaped policy frontier which divides the parameter space into two areas: one where hybrid nominal income targeting is preferred to strict inflation targeting and the other where strict inflation targeting is preferred to hybrid nominal income targeting. For most coefficient estimates reported in the literature hybrid nominal income targeting is likely to dominate strict inflation targeting as a strategy of monetary policy. We also trace out a policy frontier for the two strategies of monetary policy using a forward-looking specification as our baseline model. This policy frontier is not Ushaped; instead it implies a monotonic trade-off between the relevant parameters. In this model the strict inflation target becomes more attractive relative to the hybrid nominal income target as the Phillips Curve parameter increases in size. A strict inflation target is more likely to dominate a nominal income growth rate target than a hybrid nominal income target for certain values of the Phillips Curve parameter. JEL Classification: E5
High-performance MoS2 transistors with low-resistance molybdenum contacts

In this Letter, molybdenum (Mo) is introduced and evaluated as an alternative contact metal to atomically-thin molybdenum disulphide (MoS2), and high-performance field-effect transistors are experimentally demonstrated. In order to understand the physical nature of the interface and highlight the role of the various factors contributing to the Mo-MoS2 contacts, density functional theory (DFT) simulations are employed, which reveal that Mo can form high quality contact interface with monolayer MoS2 with zero tunnel barrier and zero Schottky barrier under source/drain contact, as well as an ultra-low Schottky barrier (0.1 eV) at source/drain-channel junction due to strong Fermi level pinning. In agreement with the DFT simulations, high mobility, high ON-current, and low contact resistance are experimentally demonstrated on both monolayer and multilayer MoS2 transistors using Mo contacts. The results obtained not only reveal the advantages of using Mo as a contact metal for MoS2 but also highlight the fact that the properties of contacts with 2-dimensional materials cannot be intuitively predicted by solely considering work function values and Schottky theory.
SWIFT J1753.5–0127: A Surprising Optical/X-Ray Cross-Correlation Function

We have conducted simultaneous optical and X-ray observations of SWIFT J1753.5–0127 with RXTE and ULTRACAM, while the system persisted in its relatively bright low/hard state. In the cross-correlation function, we find that the optical emission, with a broad negative peak, leads the X-ray emission by a few seconds and has a smaller positive peak at positive lags. This is markedly different from what was seen for the similarly interesting system XTE J1118+480, and it is the first time that such a correlation function has been so clearly measured. We suggest a physical scenario for its origin.
In vitro study of fracture strength of provisional crown materials

PURPOSE The purpose of this report was to evaluate the effect of the fabrication method and material type on the fracture strength of provisional crowns. MATERIALS AND METHODS A master model with one crown (maxillary left second premolar) was manufactured from Cr-Co alloy. The master model was scanned, and the data set was transferred to a CAD/CAM unit (Yenamak D50, Yenadent Ltd, Istanbul, Turkey) for the Cercon Base group. For the other groups, temporary crowns were produced by direct fabrication methods (Imident, Temdent, Structur Premium, Takilon, Systemp c&b II, and Acrytemp). The specimens were subjected to water storage at 37℃ for 24 hours, and then they were thermocycled (TC, 5000×, 5-55℃) (n=10). The maximum force at fracture (Fmax) was measured in a universal test machine at 1 mm/min. Data was analyzed by non-parametric statistics (α=.05). RESULTS Fmax values varied between 711.09-1392.1 N. In the PMMA groups, Takilon showed the lowest values (711.09 N), and Cercon Base showed the highest values (959.59 N). In the composite groups, Structur Premium showed the highest values (1392.1 N), and Acrytemp showed the lowest values (910.05 N). The composite groups showed significantly higher values than the PMMA groups (P=.01). CONCLUSION Composite-based materials showed significantly higher fracture strengths than PMMA-based materials. The CAD-CAM technique offers more advantages than the direct technique.
A Comparative Static Model of the Relationship between Immigration and the Short-Run Job Prospects of Unemployed Residents

A novel theoretical approach is developed to illustrate the consequences of immigration for the probability that unemployed residents gain a job. Through the use of the vacancies to unemployment ratio it is shown that immigration in theory can either increase or decrease unemployed residents' employment probabilities, but that, contrary to populist rhetoric, an increase is more likely the more recessed is the labour market. With reference to feasible Australian values of the parameters of interest, it is demonstrated that in practically all circumstances immigration increases the overall employment prospects of unemployed residents. Even so, the analysis is very short run, and strong conclusions as to what might be happening over the longer term are not appropriate. Copyright 1999 by The Economic Society of Australia.
The process of change experienced by pre-service and in-service social studies teachers in an online content area reading course

With the passing of the No Child Left Behind Act of 2001 and subsequent highstakes tests, including the Florida Comprehensive Assessment Test (FCAT), literacy has become top priority in the field of education (Florida Department of Education [FDOE], no date a; NCLB, 2002). Though social studies was not mentioned in NCLB, nor is it tested by the FCAT, social studies teachers are expected to teach literacy skills in their classrooms. Social studies teachers’ accountability for literacy enhancement is evidenced by the fact that some states, including Florida, now require social studies teachers to complete a course in reading integration to qualify for teaching certification in that state
Public Education, Technological Change and Economic

We introduce publicly funded education in R&D-based economic growth theory. The framework allows us to i) incorporate a realistic process of human capital accumulation for industrialized countries, ii) reconcile R&D-based growth theory with the empirical evidence on the relationship between economic prosperity and population growth, iii) revise the policy invariance result of semi-endogenous growth frameworks, and iv) show that the transitional effects of an education reform tend to be qualitatively different from its long-run impact.
Spherical formation tracking control of second-order nonlinear agents with directed communication

This article proposes a solution to the problem of forcing multiple agents to formation tracking a family of given concentric spheres when the communication topology is directed. Each agent under consideration has intrinsic second-order nonlinear dynamics. By using our previous concentric compression method, the cooperative control system can be regarded as a cascade system composed of the spherical tracking subsystem and the formation subsystem with the spherical tracking error as input. The algorithm for directed interaction is constructed by separately designing the control input projected onto the normal vector to the surface of sphere and the direction of spherical meridian for the spherical tracking subsystem, and the control input projected onto the direction of spherical parallel for formation motion. The asymptotic stability of the system is proved by using the tools of Input-to-State stability (ISS) theory. The effectiveness of the analytical results is verified by numerical simulations.
Impact of pesticide use on the health of farmers : A study in Barak valley , Assam ( India )

A study was carried out in the three districts of Barak valley (Cachar, Karimganj and Hailakandi) Assam, India to ascertain the variety of pesticides that are used in the agriculture sector and their probable impact on the health of farmers. The study revealed that the farmers often use pesticides ranging from high to extremely hazardous categories like Organochlorides, Organophosphates and Carbamates. Various signs and symptoms of diseases/ physiological disorders were observed; and the relative risk (RR) was also observed to be high. Lack of adoption of adequate protective measures were noticed to have increased the declining state of the health of farmers in the region.
Structure of the Electrospheres of Bare Strange Stars

We consider a thin (~102-103 fm) layer of electrons (the electrosphere) at the quark surface of a bare strange star, taking into account the surface effects at the boundary with the vacuum. The quark surface holds the electron layer by an extremely strong electric field, generated in the electrosphere to prevent the electrons from escaping to infinity by counterbalancing the degeneracy and thermal pressure. Because of the surface tension and depletion of s quarks a very thin (a few fm) charged layer of quarks forms at the surface of the star. The formation of this layer modifies the structure of the electrosphere by significantly changing the electric field and the density of the electrons, in comparison with the case in which the surface effects are ignored. Some consequences of the modification of the electrosphere structure on the properties of strange stars are briefly discussed.
A Robust Nonlinear Observer for Real-Time Attitude Estimation Using Low-Cost MEMS Inertial Sensors

This paper deals with the attitude estimation of a rigid body equipped with angular velocity sensors and reference vector sensors. A quaternion-based nonlinear observer is proposed in order to fuse all information sources and to obtain an accurate estimation of the attitude. It is shown that the observer error dynamics can be separated into two passive subsystems connected in “feedback”. Then, this property is used to show that the error dynamics is input-to-state stable when the measurement disturbance is seen as an input and the error as the state. These results allow one to affirm that the observer is “robustly stable”. The proposed observer is evaluated in real-time with the design and implementation of an Attitude and Heading Reference System (AHRS) based on low-cost MEMS (Micro-Electro-Mechanical Systems) Inertial Measure Unit (IMU) and magnetic sensors and a 16-bit microcontroller. The resulting estimates are compared with a high precision motion system to demonstrate its performance.
A Cloth Simulation Method Based on Differential Geometric Energy

According to the properties of bending and stretching in the cloth simulation, in order to achieve a superior cloth deformation effects, this paper proposes a new cloth simulation method based on the geometric deformation model that can preserve geometric features in the deformation better. Based on differential domain constraints condition, deformation energy function based on the different types of cloth materials is optimized. Nonlinear least squares deformation energy is the core of this differential framework. The cloth deformation is simulated interactively by increasing the related constraints and iteration methods. On the basis of design of geometric energy, transformation, and the corresponding nonlinear optimization numerical solution, the cloth deformation can be simulated more realistic. Especially, the geometric features about textile material effects can be simulated.
Roma-BZCAT: A multifrequency catalogue of Blazars

We present a new catalogue of blazars based on multi-frequency surveys and on an extensive review of the literature. Blazars are classified as BL Lacertae objects, as flat spectrum radio quas ars or as blazars of uncertain/transitional type. Each object is identified by a root name, coded as BZB, BZQ and BZU for these three subclasses respectively, and by its coordinates. This catalogue i s being built as a tool useful for the identification of the extragala ctic sources that will be detected by present and future experiments for X and gamma-ray astronomy, like Swift, AGILE, Fermi-GLAST and Simbol-X. An electronic version is available from the ASI Science Data Center web site at http://www.asdc. asi.it/bzcat.
A term-based inverted index partitioning model for efficient distributed query processing

In a shared-nothing, distributed text retrieval system, queries are processed over an inverted index that is partitioned among a number of index servers. In practice, the index is either document-based or term-based partitioned. This choice is made depending on the properties of the underlying hardware infrastructure, query traffic distribution, and some performance and availability constraints. In query processing on retrieval systems that adopt a term-based index partitioning strategy, the high communication overhead due to the transfer of large amounts of data from the index servers forms a major performance bottleneck, deteriorating the scalability of the entire distributed retrieval system. In this work, to alleviate this problem, we propose a novel inverted index partitioning model that relies on hypergraph partitioning. In the proposed model, concurrently accessed index entries are assigned to the same index servers, based on the inverted index access patterns extracted from the past query logs. The model aims to minimize the communication overhead that will be incurred by future queries while maintaining the computational load balance among the index servers. We evaluate the performance of the proposed model through extensive experiments using a real-life text collection and a search query sample. Our results show that considerable performance gains can be achieved relative to the term-based index partitioning strategies previously proposed in literature. In most cases, however, the performance remains inferior to that attained by document-based partitioning.
Integration of the sales force: an empirical examination

This article develops and tests a model of integration of a marketing function, personal selling. The model, derived from transaction cost analysis as developed principally by Williamson, is formulated as a logistic function, which is estimated with data from the electronic components industry. As expected, integration is associated with increasing levels of asset specificity, difficulty of performance evaluation, and the combination of these two factors. Contrary to the transaction cost model, neither frequency of transactions nor interaction of specificity and environmental uncertainty is significantly related to integration. The transaction cost model improves significantly upon the fit of a simple model relating integration to company size alone. These results suggest that for studying transactions of this kind, it is fruitful to view the firm as a governance structure.
Evidence and practice in spine registries

Background and purpose — We performed a systematic review and a survey in order to (1) evaluate the evidence for the impact of spine registries on the quality of spine care, and with that, on patient-related outcomes, and (2) evaluate the methodology used to organize, analyze, and report the “quality of spine care” from spine registries. Methods — To study the impact, the literature on all spinal disorders was searched. To study methodology, the search was restricted to degenerative spinal disorders. The risk of bias in the studies included was assessed with the Newcastle-Ottawa scale. Additionally, a survey among registry representatives was performed to acquire information about the methodology and practice of existing registries. Results — 4,273 unique references up to May 2014 were identified, and 1,210 were eligible for screening and assessment. No studies on impact were identified, but 34 studies were identified to study the methodology. Half of these studies (17 of the 34) were judged to have a high risk of bias. The survey identified 25 spine registries, representing 14 countries. The organization of these registries, methods used, analytical approaches, and dissemination of results are presented. Interpretation — We found a lack of evidence that registries have had an impact on the quality of spine care, regardless of whether intervention was non-surgical and/or surgical. To improve the quality of evidence published with registry data, we present several recommendations. Application of these recommendations could lead to registries showing trends, monitoring the quality of spine care given, and ultimately improving the value of the care given to patients with degenerative spinal disorders.