Second Set Of Conditions Research Articles

Latent local-to-unity models

The article studies a class of state-space models where the state equation is a local-to-unity process. The parameter of interest is the persistence parameter of the latent process. The large sample theory for the least squares (LS) estimator and an instrumental variable (IV) estimator of the persistent parameter in the autoregressive (AR) representation of the model is developed under two sets of conditions. In the first set of conditions, the measurement error is independent and identically distributed, and the error term in the state equation is stationary and fractionally integrated with memory parameter . For both estimators, the convergence rate and the asymptotic distribution crucially depend on d. The LS estimator has a severe downward bias, which is aggravated even more by the measurement error when . The IV estimator eliminates the effects of the measurement error and reduces the bias. In the second set of conditions, the measurement error is independent but not necessarily identically distributed, and the error term in the state equation is strongly mixing. In this case, the IV estimator still leads to a smaller bias than the LS estimator. Special cases of our models and results in relation to those in the literature are discussed.

Anodization of medical grade stainless steel for improved corrosion resistance and nanostructure formation targeting biomedical applications

Stainless steel is extensively used in various biomedical engineering and hospital applications, including surgical equipment and furniture. Strong adhesion of bacteria and viruses on metal surfaces can restrict long-term utilization for biomedical applications. This study aims to develop an improved electrochemical etching protocol for the anodization of 316 L grade stainless steel (10 × 15 mm) to fabricate nanostructures for biomedical and hospital applications. Anodizing conditions were optimized using two different electrolyte solutions; HNO3: H2SO4 (1:1) and HNO3, by varying applied potential, electrolyte concentration and anodizing time. Morphology and topography of the anodized surfaces were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM). AC and DC electrochemical techniques were used to further characterize the corrosion behaviour of the nanostructured surfaces. Electrochemical optimization produced two different nanostructured surfaces with the anodizing conditions of (1) 50% HNO3 at 0.465 A/cm2 for 1 min (surface 1), and (2) 0.5 M HNO3 + H2SO4 (1:1) at 0.366 A/cm2 for 5 min (surface 2). Both processes produced nanoscale surface roughness with varying corrosion susceptibility. Surfaces anodized using 50% HNO3 comprised of ‘hierarchical roughness’ with dense spikes (10 – 20 nm in diameter), covering rock candy-like protrusion (10 - 15 µm diameter). Whereas the second set of conditions produced single scale roughness with a terrace-like topography with nanoscale ridges of 34.8 ± 1.2 nm in width atop microscale hills. Surface 2 possessed improved corrosion resistance through the formation an oxide film, while the surface 1 was more susceptible to corrosion. Overall, this study demonstrates the importance of the careful optimization of electrochemical surface treatment for medical grade stainless steel in terms of roughness of nanostructures and corrosion susceptibility.

Identifying marginal treatment effects in the presence of sample selection

This article presents identification results for the marginal treatment effect (MTE) when there is sample selection. We show that the MTE is partially identified for individuals who are always observed regardless of treatment, and derive uniformly sharp bounds on this parameter under three increasingly restrictive sets of assumptions. The first result imposes standard MTE assumptions with an unrestricted sample selection mechanism. The second set of conditions imposes monotonicity of the sample selection variable with respect to treatment, considerably shrinking the identified set. Finally, we incorporate a stochastic dominance assumption which tightens the lower bound for the MTE. Our analysis extends to discrete instruments. The results rely on a mixture reformulation of the problem where the mixture weights are identified, extending Lee’s (2009) trimming procedure to the MTE context. We propose estimators for the bounds derived and use data made available by Deb et al. (2006) to empirically illustrate the usefulness of our approach.

On the bias of adjusting for a non-differentially mismeasured discrete confounder

Abstract Biological and epidemiological phenomena are often measured with error or imperfectly captured in data. When the true state of this imperfect measure is a confounder of an outcome exposure relationship of interest, it was previously widely believed that adjustment for the mismeasured observed variables provides a less biased estimate of the true average causal effect than not adjusting. However, this is not always the case and depends on both the nature of the measurement and confounding. We describe two sets of conditions under which adjusting for a non-deferentially mismeasured proxy comes closer to the unidentifiable true average causal effect than the unadjusted or crude estimate. The first set of conditions apply when the exposure is discrete or continuous and the confounder is ordinal, and the expectation of the outcome is monotonic in the confounder for both treatment levels contrasted. The second set of conditions apply when the exposure and the confounder are categorical (nominal). In all settings, the mismeasurement must be non-differential, as differential mismeasurement, particularly an unknown pattern, can cause unpredictable results.

Determination of the Signal-To-Noise Ratio Enhancement in Comprehensive Three-Dimensional Gas Chromatography.

We investigate the extent to which comprehensive three-dimensional gas chromatography (GC3) provides a signal enhancement (SE) and a signal-to-noise ratio enhancement (S/NRel) relative to one-dimensional (1D)-GC. Specifically, the SE is defined as the ratio of the tallest 3D peak height from the GC3 separation to the 1D peak height from the unmodulated 1D-GC separation. A model is proposed which allows the analyst to predict the theoretically attainable SE (SET) based upon the peak width and sampling density inputs. The model is validated via comparison of the SET to the experimentally measured SE (SEM) obtained using total-transfer GC3 (100% duty cycle for both modulators) with time-of-flight mass spectrometry detection. Two experimental conditions were studied using the same GC3 column set, differing principally in the modulation period from the 1D to 2D columns: 4 s versus 8 s. Under the first set of conditions, the average SEM was 97 (±22), in excellent agreement with the SET of 97 (±18). The second set of conditions improved the average SEM to 181 (±27), also in agreement with the average SET of 176 (±26). The average S/NRel following correction for the mass spectrum acquisition frequency was 38.8 (±11.2) and 59.0 (±27.2) for the two sets of conditions. The enhancement in S/N is largely attributed to moving the signal to a higher frequency domain where the impact of "low frequency" noise is less detrimental. The findings here provide strong evidence that GC3 separations can provide enhanced detectability relative to 1D-GC and comprehensive two-dimensional gas chromatography (GC×GC) separations.

Identifying Marginal Treatment Effects in the Presence of Sample Selection

This article presents identification results for the marginal treatment effect (MTE) when there is sample selection. We show that the MTE is partially identified for individuals who are always observed regardless of treatment, and derive uniformly sharp bounds on this parameter under three increasingly restrictive sets of assumptions. The first result imposes standard MTE assumptions with an unrestricted sample selection mechanism. The second set of conditions imposes monotonicity of the sample selection variable with respect to treatment, considerably shrinking the identified set. Finally, we incorporate a stochastic dominance assumption which tightens the lower bound for the MTE. Our analysis extends to discrete instruments. The results rely on a mixture reformulation of the problem where the mixture weights are identified, extending Lee's (2009) trimming procedure to the MTE context. We propose estimators for the bounds derived and use data made available by Deb, Munkin, and Trivedi (2006) to empirically illustrate the usefulness of our approach.

Utilizing Native Directing Groups: Mechanistic Understanding of a Direct Arylation Leads to Formation of Tetracyclic Heterocycles via Tandem Intermolecular, Intramolecular C-H Activation.

A mechanistic study on a direct arylation using a native picolylamine directing group is reported. Kinetic studies determined the concentration dependence of substrates and catalysts, as well as catalyst degradation, which led to the development of a new set of reaction conditions capable of affording a robust kinetic profile. During reaction optimization, a small impurity was observed, which was determined to be a dual C-H activation product. A second set of conditions were found to flip the selectivity of the C-H activation to form this tetracycle in high yield. A catalytic cycle is proposed for the intermolecular/intramolecular C-H activation pathway.

Competition for novelty reduces information sampling in a research game-a registered report.

Incentive structures shape scientists' research practices. One incentive in particular, rewarding priority of publication, is hypothesized to harm scientific reliability by promoting rushed, low-quality research. Here, we develop a laboratory experiment to test whether competition affects information sampling and guessing accuracy in a game that mirrors aspects of scientific investigation. In our experiment, individuals gather data in order to guess true states of the world and face a tradeoff between guessing quickly and increasing accuracy by acquiring more information. To test whether competition affects accuracy, we compare a treatment in which individuals are rewarded for each correct guess to a treatment where individuals face the possibility of being ‘scooped’ by a competitor. In a second set of conditions, we make information acquisition contingent on solving arithmetic problems to test whether competition increases individual effort (i.e. arithmetic-problem solving speed). We find that competition causes individuals to make guesses using less information, thereby reducing their accuracy (H1a and H1b confirmed). We find no evidence that competition increases individual effort (H2, inconclusive evidence). Our experiment provides proof of concept that rewarding priority of publication can incentivize individuals to acquire less information, producing lower-quality research as a consequence.

Head Shadow and Binaural Squelch for Unilaterally Deaf Cochlear Implantees.

Cochlear implants (CIs) can improve speech-in-noise performance for listeners with unilateral sensorineural deafness. But these benefits are modest and in most cases are limited to head-shadow advantages, with little evidence of binaural squelch. The goal of the investigation was to determine whether CI listeners with normal hearing or moderate hearing loss in the contralateral ear would receive a larger head-shadow benefit for target speech and noise originating from opposite sides of the head, and whether listeners would experience binaural squelch in the free field in a test involving interfering talkers. Eleven CI listeners performed a speech-identification task in the presence of interfering noise or speech. Six listeners had single-sided deafness (normal or near-normal audiometric thresholds in the acoustic ear) and five had asymmetric hearing loss (hearing loss in the acoustic ear treated with a hearing aid). Listeners were tested with the acoustic ear only and bilaterally with the CI turned on. One set of conditions examined head-shadow effects with target speech and masking noise presented from azimuths of 0 or ±108 degrees. A second set of conditions examined binaural squelch, with target speech presented from the front and interfering talkers symmetrically placed on both sides. On average, the largest head-shadow benefit (5 dB) occurred when the target and masking noise were presented on opposite sides of the head. Listeners also showed an average of 2 dB of squelch, but only when the target speech was masked by interfering talkers of the same sex as the target. CIs provide listeners with unilateral deafness important benefits for speech perception in complex spatial environments, including a larger head-shadow benefit when speech and noise originate on opposite sides of the head, and an improved ability to perceptually organize an auditory scene with multiple competing voices.The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or US Government.

Combined effects of evaporation and cavitation on the performance of a renewable energy powered natural vacuum desalination unit in Bahrain

The renewable energy powered natural vacuum desalination unit (NVDU) presents a promising alternative technique for seawater desalination and wastewater treatment, with low energy consumption, simple technology, and resulting clean environment. The problem of the low daily productivity of the NVDU motivated researchers to investigate various means of improving its productivity and thermal efficiency in order to reduce the production cost of freshwater. This study investigates experimentally the performance of the NVDU under the combined effects of evaporation and cavitation on freshwater production rate. The NVDU consists of an inverse U-shaped pipe, with one side acting as the evaporator and the other side as the condenser. The experiments were conducted under three different sets of conditions. The first had ambient conditions on both sides, the second used a water-ring vacuum pump to create a buoyancy effect, and the third was similar to the second set of conditions, but with cooling of the condensation side. The results show that the last case increased the freshwater production rate by approximately 70 times compared to the first case, while in the second case, the production rate was roughly 13 times better than in the first. These results could be attributed to the combined effects of evaporation and cavitation. This attribution is supported by the visualization of bubble motions.

The Nature of Epistemic Trust

This paper offers an analysis of the nature of epistemic trust (ET). With increased philosophical attention to social epistemology in general and testimony in particular, the role for an epistemic or intellectual version of trust has loomed large in recent debates. But, too often, epistemologists talk about trust without really providing a sustained examination of the concept. After some introductory comments, I begin by addressing various components key to trust simpliciter. In particular, I examine what we might think of when we consider what it means to place trust in someone. Once we have examined trust in general, we can modify this discussion to derive an epistemic version of trust—placing trust in someone for an epistemic reason. I argue that ET includes four components: belief, communication, reliance, and confidence. The first two sets (belief and communication) are distinctively epistemic and the second set of conditions (reliance and confidence) form the core of any kind of trust. Put together, both strands of concepts yield a distinctively epistemic version of trust. Together, these four conditions account for when H places ET in S that/for p. I end by addressing alternative accounts of ET and argue that they are all lacking.

Bijective Mappings of Meshes with Boundary and the Degree in Mesh Processing

This paper introduces three sets of sufficient conditions for generating bijective simplicial mappings of manifold meshes. A necessary condition for a simplicial mapping of a mesh to be injective is that it either maintains the orientation of all elements or flips all the elements. However, this condition is known to be insufficient for injectivity of a simplicial map. In this paper we provide additional simple conditions that, together with the above-mentioned necessary condition, guarantee injectivity of the simplicial map. The first set of conditions generalizes classical global inversion theorems to the mesh (piecewise-linear) case. That is, it proves that in the case where the boundary simplicial map is bijective and the necessary condition holds, the map is injective and onto the target domain. The second set of conditions is concerned with mapping of a mesh to a polytope. It replaces the (often hard) requirement of a bijective boundary map with a collection of linear constraints and guarantees that the resulting map is injective over the interior of the mesh and onto. These linear conditions provide a practical tool for optimizing a map of the mesh onto a given polytope while allowing the boundary map to adjust freely and keeping the injectivity property in the interior of the mesh. Allowing more freedom in the boundary conditions is useful for two reasons: (a) it circumvents the hard task of providing a bijective boundary map, and (b) it allows one to optimize the boundary map together with the simplicial map to achieve lower energy levels. The third set of conditions adds to the second set the requirement that the boundary maps be orientation preserving as well (with a proper definition of boundary map orientation). This set of conditions guarantees that the map is injective on the boundary of the mesh as well as its interior. Several experiments using the sufficient conditions are shown for mapping triangular meshes. A secondary goal of this paper is to advocate and develop the tool of degree in the context of mesh processing.

Stereoscopy benefits processing of dynamic visual scenes by disambiguating object occlusions

How and to what extent stereoscopic cues help process dynamic visual scenes is still unknown. As we navigate in crowds or when we play sports we are often obliged to make rapid decisions in complex motion environments while attending to multiple elements. Stereoscopy can improve speed thresholds for a multiple object tracking (MOT) (Faubert & Sidebottom, 2012), but the nature of this advantage remains undetermined. From an attention perspective, there are at least two possible hypotheses to explain this advantage. One possibility is that stereoscopy reduces the attentional bottleneck as seen in 2-dimensional MOT environments (Intrilligator & Canavagh, 2001) by distributing attention uniformly in 3D space. Another hypothesis is that the stereoscopy helps attentional tracking by segregating the target and the non-target objects during occlusions. We have addressed these hypotheses by testing subjects with and without stereoscopic cues for different stimulus configurations in which pairs of spheres were rotating in orbit with one another in a 3D virtual space. In one set of conditions, object pairs rotated without ever occluding each other. In the second set of conditions, the objects occasionally occluded each other as they were rotating around an axis perpendicular to the observer. All conditions consisted of 4 pairs of spheres presented in each quadrant of the visual field at 20 degrees of eccentricity. Stereoscopy improved MOT speed threshold by a factor of about 3 when objects occluded each other, but slightly, yet significantly, impaired speed threshold by about 18% when objects did not occlude each other. We conclude that the overall benefit of stereoscopy for processing dynamic scenes comes from improved attention tracking by disambiguating targets from non-targets during occlusions. Conversely, stereoscopic cues were a disadvantage in absence of occlusions. Meeting abstract presented at VSS 2013

Cross Border Transfer of Registered Office: Moving Beyond Forms

The decision in Daily Mail has come as a result of the resolution of the Member States to endorse a plurality of national legal solutions in the field of tax and corporate laws. The free movement provisions must be understood against this background and keeping in mind that no matter which “interface program” is to be used the system as a whole, i.e. the internal market, must be effective and coherent. The term “interface program” is used here as a metaphoric representation for the set of rules enshrined in national tax and corporate legislation that stipulate conditions for the entry and exit of companies.Among the exit conditions, the liquidation or winding-up of companies as a prerequisite for the cross-border transfer is the most radical one. It’s the main pursuit of this study to scrutinize the legality of liquidation in relation to cross-border movement of companies, which presupposes a change of the applicable law.Once a company is lawfully established in the State of origin and its transformation into a company governed by a different national corporate law is allowed by the State of destination, the movement represents a matter falling within the scope the Article 49 TFEU. Implicitly any restrictions imposed on the movement will be subject to the Treaty provisions.The present study makes the distinction between the conditions imposed by the State of destination, which concern rules on company transformations under the national laws and the ones imposed by the State of origin on an emigrating company. The first set of conditions falls within the State competence to determine the formal requirements necessary for the acquirement of legal status under the domestic laws, while the second set of conditions can only be applied in order to preserve the protection of rights originating before the transfer.The liquidation belongs to the latter set of conditions and according to the findings of this study, even if it is not generally excluded, the application of such restriction in a specific case would be rarely, if ever, found to be proportionate and its lack of proportionality will render it illegal under the Union law.

A biomechanical model of swallowing for understanding the influence of saliva and food bolus viscosity on flavor release

After swallowing a liquid or a semi-liquid food product, a thin film responsible for the dynamic profile of aroma release coats the pharyngeal mucosa. The objective of the present article was to understand and quantify physical mechanisms explaining pharyngeal mucosa coating. An elastohydrodynamic model of swallowing was developed for Newtonian liquids that focused on the most occluded region of the pharyngeal peristaltic wave. The model took lubrication by saliva film and mucosa deformability into account. Food bolus flow rate and generated load were predicted as functions of three dimensionless variables: the dimensionless saliva flow rate, the viscosity ratio between saliva and the food bolus, and the elasticity number. Considering physiological conditions, the results were applied to predict aroma release kinetics. Two sets of conditions were distinguished. The first one was obtained when the saliva film is thin, in which case food bolus viscosity has a strong impact on mucosa coating and on flavor release. More importantly, we demonstrated the existence of a second set of conditions. It was obtained when the saliva film is thick and the food bolus coating the mucosa is very diluted by saliva during the swallowing process and the impact of its viscosity on flavor release is weak. This last phenomenon explains physically in vivo observations for Newtonian food products found in the literature. Moreover, in this case, the predicted thickness of the mix of food bolus with saliva coating the mucosa is approximately of 20 μm; value in agreement with orders of magnitude found in the literature.

Propagation of a plane wave to a materially uniform but inhomogeneous body

We produce the equations of small deformations superimposed upon large for materially uniform but inhomogeneous bodies and specialize to an isotropic material and to a homogeneous finite elastic deformation. By assuming the small deformation to be a plane wave, a set of equations for the amplitude of the wave is produced which is accompanied by an additional set of conditions. By requiring a non-trivial solution for the amplitude, we obtain the secular equation and from it a set of necessary and sufficient conditions for having a real wave speed. The second set of conditions that have to be satisfied is due to the materials inhomogeneity. Essentially, the present analysis enhances the approach of Hayes and Rivlin for materially uniform but inhomogeneous bodies. The outcome is that for such bodies the restrictions on the constitutive law for having real wave speeds for an isotropic material subjected to a pure homogeneous deformation involves the field of the inhomogeneity as well.

Asymptotically optimal estimating equation with strongly consistent solutions for longitudinal data

In this article, we introduce a conditional marginal model for longitudinal data, in which the residuals form a martingale difference sequence. This model allows us to consider a rich class of estimating equations which contains several estimating equations proposed in the literature. A particular sequence of estimating equations in this class contains a random matrix R ∗−1 (β) as a replacement for the "true" conditional correlation matrix of the ith individual. Using the approach of (12), we identify some sufficient conditions under which this particular sequence of equations is asymptotically optimal (in our class). In the second part of the article, we identify a second set of conditions under which we prove the existence and strong consistency of a sequence of estimators of β defined as roots of estimation equations which are martingale transforms (in particular, roots of the sequence of asymptotically optimal equations).

The First-Order Approach to Moral Hazard Problems with Hidden Saving: The Case of CARA Utility

For CARA preferences, this paper examines the rst order approach to moral hazard problems in which the agent can secretly save and borrow. The paper shows that hidden saving constrains the concavity of the agent’s problem even for CARA utility and additively separable eort disutility in an important way. We derive two sets of sucient conditions for the validity of the rst order approach in this setup. First, we strengthen the classic approach by Mirrlees (1979) and Rogerson (1985). We obtain a second set of conditions by using the theory of total positivity (Karlin 1968).

Understanding the importance of the viscosity contrast between the sample solvent plug and the mobile phase and its potential consequence in two-dimensional high-performance liquid chromatography

The effect of solvent viscosity mismatch on elution performance in reversed-phase HPLC was studied using moment analysis. Two conditions were tested: (1) the mobile phase viscosity was less than the injection plug viscosity, and (2) the mobile phase viscosity was greater than the injection plug viscosity. Under the first condition, retention time and elution performance decreased as the viscosity contrast between the mobile phase and injection plug increased. The effect on performance was more marked as the injection volume increased. A decrease in performance of 12% for compounds with retention factors up to 2.8 was apparent even when the viscosity contrast was only 0.165 cP. In the second set of conditions, elution performance was actually observed to increase, by as much as 25% for a 40 μL injection, as the viscosity contrast between the mobile phase and the solute plug increased. No change in the retention factor was observed. This behaviour was attributed to the shape of an injection plug as it enters into the column, whereby a low viscosity plug permeates away from the wall when the column contains a higher viscosity mobile phase, and vice a versa for a high viscosity plug entering a low viscosity mobile phase. At no stage was either a band splitting or shoulders observed with viscosity contrasts up to 1.283 cP, as could have been expected.

The Concept of Co-option: Why Evolution Often Looks Miraculous

Darwin believed that evolution generally occurred through a series of small, gradual changes. This proposal was counter-intuitive to many people because it seemed likely that “transitional” forms would not survive. Darwin, and later Cuènot, recognized that this problem was easily solved if characters that had evolved for one reason changed their function at a later time with little to no concurrent structural modification, at least initially. In other words, traits that had evolved under one set of conditions were co-opted to serve a different function under a second set of conditions. This meant that organisms carried with them in the structures of their genes, proteins, morphological, physiological, and behavioral characters the potential for rapid evolutionary change, so rapid, indeed, that the process looked miraculous and Lamarckian. In this paper, I discuss some of the paradigm examples of co-option, from genes to behavior.