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Do small wording differences in message-based behavioral interventions have outsized effects on behavior? An influential initial study, examining this question in the domain of political behavior using two small-scale field experiments, argues that subtle linguistic cues in voter mobilization messages describing someone as a voter (noun) instead of one who votes (verb) dramatically increases turnout rates by activating a person's social identity as a voter. Two subsequent large-scale replication field experiments challenged this claim, finding no effect even in electorally competitive settings. However, these experiments may not have reproduced the psychological context needed to motivate behavioral change because they did not occur in highly competitive and highly salient electoral contexts. Addressing this major criticism, we conduct a large-scale, preregistered replication field experiment in the 2016 presidential election. We find no evidence that noun wording increases turnout compared to verb wording in this highly salient electoral context, even in competitive states.
Although the use of nonhost plants intercropped among host crops has been a standard agricultural practice for reducing insect herbivory for millennia, the use of nonhost signals to deter forest pests is much more recent, having been developed over the past several decades. Early exploratory studies with synthetic nonhost volatile semiochemicals led to targeted electrophysiological and trapping experiments on a variety of bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) across three continents. This work disclosed a suite of antennally and behaviourally active nonhost volatiles, which are detected in common across a range of coniferophagous bark beetles. It also established the fact that dispersing bark and ambrosia beetles detect nonhost signals while in flight and avoid nonhost trees without necessarily landing on them. Later work showed that groups of synthetic nonhost volatiles, sometimes combined with insect-derived antiaggregants, are effective in protecting individual trees and forest stands. Further work in this system may lead to the development of a variety of new and useful tactics for use in various integrated pest management strategies.
Microvascular health is a main determinant of coronary blood flow reserve and myocardial vascular resistance. Extracardiac capillary abnormality has been reported in subjects at increased coronary heart disease risk, such as prehypertension, hypertension, diabetes, hyperlipidemia, and atherosclerosis. We have reported cardiovascular dysfunction in a cohort of maternal nutrient reduction (MNR)-induced intrauterine growth restriction (IUGR) baboon offspring. Here we test the hypothesis that there is oral capillary rarefaction associated with MNR-induced IUGR. Capillary density was quantified using in vivo high-power capillaroscopy on seven middle-aged (~10.7 yr; human equivalent ~40 yr) male IUGR baboons and seven male age-matched controls in the lateral buccal and inferior labial mucosa. While no difference was found between groups in either area by fraction area or optical density for these vascular beds derived from fetal preductal vessels, further studies are needed on post-ductal vascular beds, retina, and function.
Studies examining OC phenomena in schizophrenic and schizoaffective disorders have shown a prevalence of such phenomena in 1 to 60% of schizophrenic or schizoaffective patients. In this prospective study, about 10% of 150 male patients suffering from acute psychotic disorders (fulfilling DSM-IV criteria for Schizophrenia or Schizoaffective Disorder) were found to have OC symptoms. These symptoms showed no correlation to the type and severity of psychosis. As only 19% of the patients with obsessions and compulsions during acute psychosis showed an obsessive-compulsive personality disorder prior to their psychotic episodes, it may be concluded that there is no clear linkage between intrapsychotic OC phenomena and premorbid anancastic personality traits.
The ability of the aorta to buffer blood flow and provide diastolic perfusion (Windkessel function) is a determinant of cardiovascular health. We have reported cardiac dysfunction indicating downstream vascular abnormalities in young adult baboons who were intrauterine growth restricted (IUGR) at birth as a result of moderate maternal nutrient reduction. Using 3 T MRI, we examined IUGR offspring (eight male, eight female; 5.7 years; human equivalent 25 years) and age-matched controls (eight male, eight female; 5.6 years) to quantify distal descending aortic cross-section (AC) and distensibility (AD). ANOVA showed decreased IUGR AC/body surface area (0.9±0.05 cm2/m2v. 1.2±0.06 cm2/m2, M±s.e.m., P<0.005) and AD (1.7±0.2 v. 4.0±0.5×10−3/mmHg, P<0.005) without sex difference or group-sex interaction, suggesting intrinsic vascular pathology and impaired development persisting in adulthood. Future studies should evaluate potential consequences of these changes on coronary perfusion, afterload and blood pressure.
Doubts about the integrity of ballot secrecy persist and depress political participation among the American public. Prior experiments have shown that official communications directly addressing these doubts increase turnout among recently registered voters who had not previously voted, but evaluations of similar messages sent by nongovernmental campaigns have yielded only suggestive effects. We build on past research and analyze two large-scale field experiments where a private nonpartisan nonprofit group sought to increase turnout by emphasizing ballot secrecy assurances alongside a reminder to vote in a direct mail voter mobilization campaign during the 2014 midterm election. Our main finding is that a private group’s mailing increases turnout by about 1 percentage point among recently registered nonvoters. This finding is precisely estimated and robust across state political contexts, but is not statistically distinguishable from the effect of a standard voter mobilization appeal. Implications and directions for future research are discussed.
Several authors claimed that expression of suicidal ideation is one of the most important predictors of completed suicide. However, the strength of the association between suicidal ideation and subsequent completed suicide has not been firmly established in different populations. Furthermore, the absolute suicide risk after expression of suicidal ideation is unknown. In this meta-analysis, we examined whether the expression of suicidal ideation predicted subsequent completed suicide in various populations, including both psychiatric and non-psychiatric populations.
A meta-analysis of cohort and case–control studies that assessed suicidal ideation as determinant for completed suicide in adults. Two independent reviewers screened 5726 articles for eligibility and extracted data of the 81 included studies. Pooled risk ratios were estimated in a random effects model stratified for different populations. Meta-regression analysis was used to determine suicide risk during the first year of follow-up.
The risk for completed suicide was clearly higher in people who had expressed suicidal ideation compared with people who had not, with substantial variation between the different populations: risk ratio ranging from 2.35 (95% confidence interval (CI) 1.43–3.87) in affective disorder populations to 8.00 (95% CI 5.46–11.7) in non-psychiatric populations. In contrast, the suicide risk after expression of suicidal ideation in the first year of follow-up was higher in psychiatric patients (risk 1.40%, 95% CI 0.74–2.64) than in non-psychiatric participants (risk 0.23%, 95% CI 0.10–0.54). Past suicide attempt-adjusted risk ratios were not pooled due to large underreporting.
Assessment of suicidal ideation is of priority in psychiatric patients. Expression of suicidal ideation in psychiatric patients should prompt secondary prevention strategies to reduce their substantial increased risk of suicide.
We recently showed that the mRNA expression of genes encoding for specific nutrient sensing receptors, namely the free fatty acid receptors (FFAR) 1, 2, 3, and the hydroxycarboxylic acid receptor (HCAR) 2, undergo characteristic changes during the transition from late pregnancy to lactation in certain adipose tissues (AT) of dairy cows. We hypothesised that divergent energy intake achieved by feeding diets with either high or low portions of concentrate (60% v. 30% concentrate on a dry matter basis) will alter the mRNA expression of FFAR 1, 2, 3, as well as HCAR2 in subcutaneous (SCAT) and retroperitoneal AT (RPAT) of dairy cows in the first 3 weeks postpartum (p.p.). For this purpose, 20 multiparous German Holstein cows were allocated to either the high concentrate ration (HC, n=10) or the low concentrate ration (LC, n=10) from day 1 to 21 p.p. Serum samples and biopsies of SCAT (tail head) and RPAT (above the peritoneum) were obtained at day −21, 1 and 21 relative to parturition. The mRNA abundances were measured by quantitative PCR. The concentrations of short-chain fatty acid (SCFA) in serum were measured by gas chromatography-flame ionisation detector. The FFAR1 and FFAR2 mRNA abundance in RPAT was higher at day −21 compared to day 1. At day 21 p.p. the FFAR2 mRNA abundance was 2.5-fold higher in RPAT of the LC animals compared to the HC cows. The FFAR3 mRNA abundance tended to lower values in SCAT of the LC group at day 21. The HCAR2 mRNA abundance was neither affected by time nor by feeding in both AT. On day 21 p.p. the HC group had 1.7-fold greater serum concentrations of propionic acid and lower concentrations of acetic acid (trend: 1.2-fold lower) compared with the LC group. Positive correlations between the mRNA abundance of HCAR2 and peroxisome proliferator-activated receptor γ-2 (PPARG2) indicate a link between HCAR2 and PPARG2 in both AT. We observed an inverse regulation of FFAR2 and FFAR3 expression over time and both receptors also showed an inverse mRNA abundance as induced by different portions of concentrate. Thus, indicating divergent nutrient sensing of both receptors in AT during the transition period. We propose that the different manifestation of negative EB in both groups at day 21 after parturition affect at least FFAR2 expression in RPAT.
Thermoelectric (TE) generators have very important applications, such as emerging automotive waste heat recovery and cooling applications. However, reliable transport properties characterization techniques are needed in order to scale-up module production and thermoelectric generator design. DOE round-robin testing found that literature values for figure of merit (ZT) are sometimes not reproducible in part for the lack of standardization of transport properties measurements. In Sandia National Laboratories (SNL), we have been optimizing transport properties measurements techniques of TE materials and modules. We have been using commercial and custom-built instruments to analyze the performance of TE materials and modules. We developed a reliable procedure to measure thermal conductivity, seebeck coefficient and resistivity of TE materials to calculate the ZT as function of temperature. We use NIST standards to validate our procedures and measure multiple samples of each specific material to establish consistency. Using these developed thermoelectric capabilities, we studied transport properties of Bi2Te3 based alloys thermal aged up to 2 years. Parallel with analytical and microscopy studies, we correlated transport properties changes with chemical changes. Also, we have developed a resistance mapping setup to measure the contact resistance of Au contacts on TE materials and TE modules as a whole in a non-destructive way. The development of novel but reliable characterization techniques has been fundamental to better understand TE materials as function of aging time, temperature and environmental conditions.
Salinity gradient is an enormous source of clean energy. A process for potential generation from an ionic concentration gradient produced in single and multicell assembly is presented. The ionic gradient is created using a fuel cell type cell with a micro-porous ion exchange membrane, both anionic (AEM) and cationic (CEM). Various salinity gradients, Salt : Fresh, from 100 : 0 to 16000 : 0 was established using NaCl solution, in the electrode chambers. A potential of 20 mV/cm to 25 mV/cm can be realized at ambient temperatures and pressures for a bipolar AEM/CEM cell. The performance was optimized for various static and dynamic flow rates of the saline and fresh water. The cell performance can further be optimized for Membrane Electrode System (MES) morphology. A multicell unit was assembled and the results presented for various conditions like concentration gradients, flow rates and pressure. The thermodynamic and electrical efficiency needs to be evaluated for various gradients and flow rates. The relation with number of valance electrons/ ion and the potential generated changes for various dynamic condition of salinity. The higher the salinity gradient the larger is the potential generated. This is limited by the membrane characteristics. There exists a monotonic relation between the number of valence electron/ion/unit time and the potential generated up to about 16000 concentration. The membrane characteristics have been studied for optimal ion crossover for various gradients and flow. The graph between ln (gradient) versus Voltage provides insights into this process. This presents a very cost effective and clean process of energy conversion.
In this work, LiFePO4 (LFP) particles were synthesized through an ionic liquid medium. Through the fabrication of LFP particles, we observed the formation of quasi-1−dimensional (1D) structures. The characterization of phases found in the reaction, through time-dependent studies, have led us to propose a possible scheme for particle formation.
Synthesized material was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and x-ray diffraction (XRD). We also report our analysis on particle morphology and crystallinity of LFP particles synthesized through an ionic liquid−mediated process.
Li/S batteries have received too much attention due to their considerable theoretical energy density suitable for high energy applications. Here, we study the consequences of the SEI layer on internal resistance of the single battery cell due to polysulfide (PS) shuttling. The growth in resistance is related to the capacity fading of the cell. Using a model of series resistors, the total internal ionic resistance over cycling performance is expressed and compared for various nanostructured cathodes at different rates. It has been shown that SEI layer is the most significant factor in increasing of ionic resistance at the beginning of the battery aging, while electrode degradation and other phenomena are dominating resistance rise over higher cycles. We also demonstrate that cathodes with smaller equivalent porosity represent an excellent performance in preventing internal resistance enhancement.
In this work, the structure and conductive structure of perfluorinated sulfonated ionomers were investigated by tapping mode, material sensitive atomic force microscopy (AFM). At cross section of membranes, large ordered lamellar-like areas were found. From adhesion force mappings, approximately 50 nm large water-rich areas could be identified by their low adhesion. These areas were interpreted as ionically conductive phase. They appeared circular and isolated before any forced current flow through the sample (activation). After activation, branched, long and flat ionically conductive phase structures in direction of applied voltage were found. They were interpreted as the formation of a continuous ionically conducting network formed by the current flow. In a second part, the material sensitive imaging was used to analyze the distribution of ionomer and platinum covered carbon particles in fuel cell electrodes. The analysis was based on the high adhesion of ionomers compared to the carbon supported catalyst particles.
Direct Methanol Fuel Cell, DMFC, technology, can be used for fabrication of sensors for volatile organic compounds like alcohols. A fundamental limitation in DMFC is methanol crossover. In this process methanol diffuses from the anode through the electrolyte to the cathode, where it reacts directly with the oxygen and produces no electrical current from the cell. This also results in poisoning of the cathode catalysts. The designed and fabrication of the sensor is by means of micro electro mechanical systems (MEMS) fabrication technology with electrochemical inputs. To achieve this we have used a passive mode design protocol using COMSOL Multiphysics. The design and simulation would involve optimization of various parameters, in the construction of the cell. We can optimize the overall power density and hence the sensitivity of the sensor by the modification of various parameters like the area of the working electrodes, separation distance and the electrode-electrolyte interface. A passive mode design protocol, for a cm cell area, using various parametric functions, and interfacing Darcy’s law of fluidic flow through a porous medium, under specific pressure and temperature, was applied. The designing involves the construction of gas diffusion layers using carbon cloth for anode and cathode with various parametric variations. Nafion membrane was selected as proton exchange membrane for the construction with different interface structure to analyze the sensor’s performance. Platinum and various alloy catalysts like Pt-Ru, Pt-Fe, Pt-Sn and Pt-Mo was chosen as the working catalysts. The parametric functions of the cell were optimized for ampherometric detection. It is proposed to design a MEMS based sensor with microfludic interconnects and its response characteristics will be studied.
GaN and its alloys are promising candidates for high temperature thermoelectric (TE) materials due to their high Seebeck coefficient and high thermal and mechanical stability. Moreover, these materials can overcome the toxicity concern of current Te-based TE materials, such as Bi2Te3 and PbTe. These materials have recently shown a higher Seebeck coefficient than that of SiGe in high temperature region because their large bandgap characteristic eliminates the bipolar conduction. In this study, we report the room temperature thermoelectric properties of p-type Mg doped GaN, grown by metalorganic chemical vapor deposition (MOCVD) on sapphire substrate with various carrier concentrations. Undoped and n-type GaN are also incorporated with p-type GaN films to make comparison. The structural, optical, electrical, and thermal properties of the samples were examined by X-ray diffraction, photoluminescence, van der Pauw hall-effect, and thermal gradient methods, respectively. The Seebeck coefficient ranging from 710-900µV/K at room temperature of Mg: GaN were observed, which further indicated their potential TE applications.
We report experiments and molecular dynamics calculations on the kinetics of electrodeposited lithium dendrites relaxation as a function of temperature and time. We found that the experimental average length of dendrite population decays via stretched exponential functions of time toward limiting values that depend inversely on temperature. The experimental activation energy derived from initial rates as Ea∼ 6-7 kcal/mole, which is closely matched by MD calculations, based on the ReaxFF force field for metallic lithium. Simulations reveal that relaxation proceeds in several steps via increasingly larger activation barriers. Incomplete relaxation at lower temperatures is therefore interpreted a manifestation of cooperative atomic motions into discrete topologies that frustrate monotonic progress by ‘caging’.
The advancement of computational tools for material property predictions enables broad search of novel materials for various energy-related applications. However, challenges still exist in accurately predicting the mean free paths (MFPs) of electrons and phonons in a high-throughput frame for thermoelectric property predictions, which largely hinders the computation-driven search for novel materials. In this work, this need is eliminated under the small-grain-size limit, in which these MFPs are restricted by the grain sizes within a bulk material. A new criterion for ZT evaluation is proposed for general nanograined bulk materials and is demonstrated with representative oxides.