On model selection criteria for climate change impact studies

Climate change impact studies inform policymakers on the estimated damages of future climate change on economic, health and other outcomes. In most studies, an annual outcome variable is observed, e.g. annual mortality rate, along with higher-frequency regressors, e.g. daily temperature and precipitation. Practitioners use summaries of the higher-frequency regressors in fixed effects panel models. The choice over summary statistics amounts to model selection. Some practitioners use Monte Carlo cross-validation (MCCV) to justify a particular specification. However, conventional implementation of MCCV with fixed testing-to-full sample ratios tends to select over-fit models. This paper presents conditions under which MCCV, and also information criteria, can deliver consistent model selection. Previous work has established that the Bayesian information criterion (BIC) can be inconsistent for non-nested selection. We illustrate that the BIC can also be inconsistent in our framework, when all candidate models are misspecified. Our results have practical implications for empirical conventions in climate change impact studies. Specifically, they highlight the importance of a priori information provided by the scientific literature to guide the models considered for selection. We emphasize caution in interpreting model selection results in settings where the scientific literature does not specify the relationship between the outcome and the weather variables.Comment: Additional simulation results available from authors by reques

Boundary interpolation for slice hyperholomorphic Schur functions

A boundary Nevanlinna-Pick interpolation problem is posed and solved in the quaternionic setting. Given nonnegative real numbers $\kappa_1, \ldots, \kappa_N$, quaternions $p_1, \ldots, p_N$ all of modulus $1$, so that the $2$-spheres determined by each point do not intersect and $p_u \neq 1$ for $u = 1,\ldots, N$, and quaternions $s_1, \ldots, s_N$, we wish to find a slice hyperholomorphic Schur function $s$ so that $$\lim_{\substack{r\rightarrow 1\\ r\in(0,1)}} s(r p_u) = s_u\quad {\rm for} \quad u=1,\ldots, N,$$ and $$\lim_{\substack{r\rightarrow 1\\ r\in(0,1)}}\frac{1-s(rp_u)\overline{s_u}}{1-r}\le\kappa_u,\quad {\rm for} \quad u=1,\ldots, N.$$ Our arguments relies on the theory of slice hyperholomorphic functions and reproducing kernel Hilbert spaces

Grapevine virus A and grapevine virus D are serologically distantly related

Grapevine trichovirus A (GVA), B (GVB), and D (GVD) are not serologically related as ascertained by ELISA and IEM tests using polyclonal antisera A study to investigate in detail their serological relationships was carried out with a larger number of reagents, including monoclonal antibodies (MAbs), and serological techniques (ELISA, IEM, tissue blot, Western blot). The results show that (i) polyclonal antisera to GVA, GVB and GVD cross-reacted in Western blot with all antigens; (ii) one out of 4 MAbs to GVA (MAb PA3.B9) reacted in ELISA, Western blot and tissue blot with the homologous virus and GVD but not with GVB. It is concluded that GVA, GVB and GVD are serologically distantly related and that the single antigenic determinant common to GVA and GVD is likely to be a cryptotope

Thermal performance of High-Efficiency Vortex (HEV) variants: reversed arrays configuration

Convective heat transfer in the Reversed Arrays configuration of the High-Efficiency Vortex (HEV) multifunctional heat exchanger is investigated. An experimental test section constituted of a tube equipped with inclined trapezoidal vortex generators with a constant-flux heating system is designed and constructed. In this configuration, the tab inclination is opposite to the flow direction. Interactions between the tabs and the flow generate coherent structures in the form of longitudinal counter-rotating streamwise vortices enhancing radial particle dispersion, mixing, and ultimately heat transport. The original configuration in which the tabs are inclined in the flow direction is also examined. Recent in-house hydrodynamic and thermal studies have been conducted showing the interest of these configurations in mixing and heat transfer applications. The experimental data are in good agreement with the numerical results. Local Nusselt numbers show an increasing tendency in the longitudinal direction with remarkable cross-sectional variations. Global analysis of convective heat transfer reveals the superiority of the Reversed Arrays. Energy expenditures are assessed through total pressure drop measurements. A comparative analysis based on the thermal enhancement factor and Colburn factor shows that the HEV is energetically less costly than other heat exchangers with similar heat transfer capacity

Transport phenomena in chaotic flows: flux recombination HEX reactors

Rapid transport of heat and mass is required in many industrial processes. Mixing is a fundamental issue in chemical engineering applications and when exothermic reactions are involved, heat transfer capabilities of reactors and static mixers become an advantage and a necessity to ensure stable operating conditions and security standards. Enhancement of mixing and heat exchange is possible through turbulence, but vortical structures are often not feasible for highly viscous, non-Newtonian or shear sensitive fluids such as emulsions, pastes and slurries common in pharmaceutical, cosmetic and food industries. An alternative to improve transport within such materials is chaotic advection, where Lagrangian chaotic structures are induced by physical means in low-Reynolds laminar flows. Microfluidics is an increasingly active domain in which small dimensions and velocities render turbulent mixing extremely hard. Mixing by diffusion is one solution where topological mixing schemes exploiting the laminarity the flow to repeatedly fold the flow and exponentially increase the concentration gradients to obtain fast and efficient mixing by diffusion. This paper presents the first results of a study investigating laminar and turbulent mixing qualities of a Flux Recombination Hex reactor by using the chemical probe method. The geometry, exploiting a three-dimensional, steady flow configuration intended to mimic the baker’s map and enhance mixing by chaotic advection. First proposed by Chen & Meiners [1] for a microfluidic chip, it is here reproduced for investigation purposes using a stratified multiple plate manufacturing technique on a mini-scale where laminar and slightly turbulent regimes can be assessed

Kinematic mixing and heat transfer enhancement in chaotic split-and-recombine heat exchangers/reactors

Small system dimensions, low fluid velocity and high viscosity are all factors that hinder the production of turbulence. Enhancing mixing and heat transfer under these conditions, while keeping sufficient residence times and moderate pressure drops, constitutes a real challenge. Adapted to low-Reynolds flow regimes, Split-And-Recombine (SAR) static mixer and heat exchanger configurations are designed to exploit flow energy to produce chaotic advection and promote diffusion at the molecular level. The present work explores the hydrodynamic and thermal character of the SAR flow and compares, through CFD simulations, two such geometries namely SAR-1 and SAR-2, with two other reference configurations: a square three-dimensional continuous flow geometry (3D-Flow) and a plain square channel. Efficient convective heat transfer is achieved in deeply laminar creeping flow. Relative enhancements up to 1700% can be achieved compared to plain square channel flow, with a moderate increase in the pressure drop that does not exceed 17% for the SAR-2 configuration showing the better performance

Ionic composition of endolymph and perilymph in the inner ear of the oyster toadfish, Opsanus tau

Author Posting. © Marine Biological Laboratory, 2008. This article is posted here by permission of Marine Biological Laboratory for personal use, not for redistribution. The definitive version was published in Biological Bulletin 214 (2008): 83-90.The concentrations of free Na+, K+, Ca2+, and Cl-in endolymph and perilymph from the inner ear of the oyster toadfish, Opsanus tau, were measured in vivo using double-barreled ion-selective electrodes. Perilymph concentrations were similar to those measured in other species, while endolymph concentrations were similar to those measured previously in elasmobranch fish, though significantly different from concentrations reported in mammals. Perilymph concentrations (mean ± std. dev.) were as follows: Na+, 129 mmol l-1 ± 20; K+, 4.96 mmol l-1 ± 2.67; Ca2+, 1.83 mmol l-1 ± 0.27; and Cl-, 171 mmol l-1 ± 20. Saccular endolymph concentrations were Na+, 166 mmol l-1 ± 22; K+, 51.4 mmol l-1 ± 16.7; Ca2+, 2.88 mmol l-1 ± 0.27; and Cl-, 170 mmol l-1 ± 12; and semicircular canal (utricular vestibule) endolymph concentrations were Na+, 122 mmol l-1 ± 15; K+, 47.7 mmol l-1 ± 13.2; Ca2+, 1.78 mmol l-1 ± 0.48; Cl-, 176 mmol l-1 ± 27. The relatively high concentrations of Ca2+ and Na+ in the endolymph may have significant implications for the physiological function of the mechanoelectrical transduction channels in the vestibular hair cells of fish compared to those of their mammalian counterparts.This work was supported by the National Institute of Deafness and Other Communications Disorders P01 DC01837, R01 DC06685, R01 DC04928, NASA NNA-04CK67H, and NSF Igert DGE9987616

Longitudinal microstructural changes in 18 amygdala nuclei resonate with cortical circuits and phenomics.

The amygdala nuclei modulate distributed neural circuits that most likely evolved to respond to environmental threats and opportunities. So far, the specific role of unique amygdala nuclei in the context processing of salient environmental cues lacks adequate characterization across neural systems and over time. Here, we present amygdala nuclei morphometry and behavioral findings from longitudinal population data (>1400 subjects, age range 40-69 years, sampled 2-3 years apart): the UK Biobank offers exceptionally rich phenotyping along with brain morphology scans. This allows us to quantify how 18 microanatomical amygdala subregions undergo plastic changes in tandem with coupled neural systems and delineating their associated phenome-wide profiles. In the context of population change, the basal, lateral, accessory basal, and paralaminar nuclei change in lockstep with the prefrontal cortex, a region that subserves planning and decision-making. The central, medial and cortical nuclei are structurally coupled with the insular and anterior-cingulate nodes of the salience network, in addition to the MT/V5, basal ganglia, and putamen, areas proposed to represent internal bodily states and mediate attention to environmental cues. The central nucleus and anterior amygdaloid area are longitudinally tied with the inferior parietal lobule, known for a role in bodily awareness and social attention. These population-level amygdala-brain plasticity regimes in turn are linked with unique collections of phenotypes, ranging from social status and employment to sleep habits and risk taking. The obtained structural plasticity findings motivate hypotheses about the specific functions of distinct amygdala nuclei in humans

A network approach for managing and processing big cancer data in clouds

Translational cancer research requires integrative analysis of multiple levels of big cancer data to identify and treat cancer. In order to address the issues that data is decentralised, growing and continually being updated, and the content living or archiving on different information sources partially overlaps creating redundancies as well as contradictions and inconsistencies, we develop a data network model and technology for constructing and managing big cancer data. To support our data network approach for data process and analysis, we employ a semantic content network approach and adopt the CELAR cloud platform. The prototype implementation shows that the CELAR cloud can satisfy the on-demanding needs of various data resources for management and process of big cancer data

The Automation of the Extraction of Evidence masked by Steganographic Techniques in WAV and MP3 Audio Files

Antiforensics techniques and particularly steganography and cryptography have become increasingly pressing issues that affect the current digital forensics practice, both techniques are widely researched and developed as considered in the heart of the modern digital era but remain double edged swords standing between the privacy conscious and the criminally malicious, dependent on the severity of the methods deployed. This paper advances the automation of hidden evidence extraction in the context of audio files enabling the correlation between unprocessed evidence artefacts and extreme Steganographic and Cryptographic techniques using the Least Significant Bits extraction method (LSB). The research generates an in-depth review of current digital forensic toolkit and systems and formally address their capabilities in handling steganography-related cases, we opted for experimental research methodology in the form of quantitative analysis of the efficiency of detecting and extraction of hidden artefacts in WAV and MP3 audio files by comparing standard industry software. This work establishes an environment for the practical implementation and testing of the proposed approach and the new toolkit for extracting evidence hidden by Cryptographic and Steganographic techniques during forensics investigations. The proposed multi-approach automation demonstrated a huge positive impact in terms of efficiency and accuracy and notably on large audio files (MP3 and WAV) which the forensics analysis is time-consuming and requires significant computational resources and memory. However, the proposed automation may occasionally produce false positives (detecting steganography where none exists) or false negatives (failing to detect steganography that is present) but overall achieve a balance between detecting hidden data accurately along with minimising the false alarms.Comment: Wires Forensics Sciences Under Revie