Multiply Robust Causal Inference with Double Negative Control Adjustment for Categorical Unmeasured Confounding

Unmeasured confounding is a threat to causal inference in observational studies. In recent years, use of negative controls to mitigate unmeasured confounding has gained increasing recognition and popularity. Negative controls have a longstanding tradition in laboratory sciences and epidemiology to rule out non-causal explanations, although they have been used primarily for bias detection. Recently, Miao et al. (2018) have described sufficient conditions under which a pair of negative control exposure and outcome variables can be used to nonparametrically identify the average treatment effect (ATE) from observational data subject to uncontrolled confounding. In this paper, we establish nonparametric identification of the ATE under weaker conditions in the case of categorical unmeasured confounding and negative control variables. We also provide a general semiparametric framework for obtaining inferences about the ATE while leveraging information about a possibly large number of measured covariates. In particular, we derive the semiparametric efficiency bound in the nonparametric model, and we propose multiply robust and locally efficient estimators when nonparametric estimation may not be feasible. We assess the finite sample performance of our methods in extensive simulation studies. Finally, we illustrate our methods with an application to the postlicensure surveillance of vaccine safety among children

Small CO2 Sensors Operate at Lower Temperature

Solid-electrolyte-based amperometric sensors for measuring concentrations of CO2 in air are being developed for use in detection of fires, environmental monitoring, and other applications where liquid-based electrochemical cells are problematic. These sensors are small (sizes of the order of a millimeter), are robust, are amenable to batch fabrication at relatively low cost, and exhibit short response times (seconds) and wide detection ranges. A sensor of this type at a previous stage of development included a solid electrolyte of Na3Zr2Si2PO12 deposited mainly between interdigitated Pt electrodes on an alumina substrate, all overcoated with an auxiliary solid electrolyte of (Na2CO3:BaCO3 in a molar ratio of 1:1.7). It was necessary to heat this device to a temperature as high as 600 C to obtain the desired sensitivity and rapid response. Heating sensors increases the power consumption of the sensor system and complicates the use of the sensor in some applications. Thus, decreasing a sensor s power consumption while maintaining its performance is a technical goal of ongoing development

Carbon Dioxide Gas Sensors and Method of Manufacturing and Using Same

A gas sensor comprises a substrate layer; a pair of interdigitated metal electrodes, said electrodes include upper surfaces, the electrodes selected from the group consisting of Pt, Pd, Au, Ir, Ag, Ru, Rh, In, Os, and their alloys. A first layer of solid electrolyte staying in between electrode fingers and partially on said upper surfaces of said electrodes, said first layer selected from NASICON, LISICON, KSICON and.beta.''-Alumina. A second layer of metal carbonate(s) as an auxiliary electrolyte engaging said upper surfaces of the electrodes and the first solid electrolyte. The metal carbonates selected from the group consisting of the following ions Na.sup.+, K.sup.+, Li.sup.+, Ag.sup.+, H.sup.+, Pb.sup.2+, Sr.sup.2+, Ba.sup.2+, and any combination thereof. An extra layer of metal oxide selected from the group consisting of SnO.sub.2, In.sub.2O.sub.3, TiO.sub.2, WO.sub.3, ZnO, Fe.sub.2O.sub.3, ITO, CdO, U.sub.3O.sub.8, Ta.sub.2O.sub.5, BaO, MoO.sub.2, MoO.sub.3, V.sub.2O.sub.5, Nb.sub.2O.sub.5, CuO, Cr.sub.2O.sub.3, La.sub.2O.sub.3, RuO.sub.3, RuO.sub.2, ReO.sub.2, ReO.sub.3, Ag.sub.2O, CoO, Cu.sub.2O, SnO, NiO, Pr.sub.2O.sub.3, BaO, PdO.sub.2, HfO.sub.3, HfO.sub.3 or other metal oxide and their mixtures residing above and in engagement with the second electrolyte to improve sensor performance and/or to reduce sensor heating power consumption

Respiration of aged soil carbon during fall in permafrost peatlands enhanced by active layer deepening following wildfire but limited following thermokarst

Permafrost peatlands store globally significant amounts of soil organic carbon (SOC) that may be vulnerable to climate change. Permafrost thaw exposes deeper, older SOC to microbial activity, but SOC vulnerability to mineralization and release as carbon dioxide is likely influenced by the soil environmental conditions that follow thaw. Permafrost thaw in peat plateaus, the dominant type of permafrost peatlands in North America, occurs both through deepening of the active layer and through thermokarst. Active layer deepening exposes aged SOC to predominately oxic conditions, while thermokarst is associated with complete permafrost thaw which leads to ground subsidence, inundation and soil anoxic conditions. Thermokarst often follows active layer deepening, and wildfire is an important trigger of this sequence. We compared the mineralization rate of aged SOC at an intact peat plateau (∼70 cm oxic active layer), a burned peat plateau (∼120 cm oxic active layer), and a thermokarst bog (∼550 cm anoxic peat profile) by measuring respired 14C-CO2. Measurements were done in fall when surface temperatures were near-freezing while deeper soil temperatures were still close to their seasonal maxima. Aged SOC (1600 yrs BP) contributed 22.1 ± 11.3% and 3.5 ± 3.1% to soil respiration in the burned and intact peat plateau, respectively, indicating a fivefold higher rate of aged SOC mineralization in the burned than intact peat plateau (0.15 ± 0.07 versus 0.03 ± 0.03 g CO2-C m−2 d−1). None or minimal contribution of aged SOC to soil respiration was detected within the thermokarst bog, regardless of whether thaw had occurred decades or centuries ago. While more data from other sites and seasons are required, our study provides strong evidence of substantially increased respiration of aged SOC from burned peat plateaus with deepened active layer, while also suggesting inhibition of aged SOC respiration under anoxic conditions in thermokarst bogs

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed

Miniaturized metal (metal alloy)/ PdO.sub.x/SiC hydrogen and hydrocarbon gas sensors

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO.sub.x ). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600.degree. C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sized sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed

Miniaturized Metal (Metal Alloy)/PdO(x)/SiC Hydrogen and Hydrocarbon Gas Sensors

A miniaturized Schottky diode hydrogen and hydrocarbon sensor and the method of making same is disclosed and claimed. The sensor comprises a catalytic metal layer, such as palladium, a silicon carbide substrate layer and a thin barrier layer in between the catalytic and substrate layers made of palladium oxide (PdO(x)). This highly stable device provides sensitive gas detection at temperatures ranging from at least 450 to 600 C. The barrier layer prevents reactions between the catalytic metal layer and the substrate layer. Conventional semiconductor fabrication techniques are used to fabricate the small-sided sensors. The use of a thicker palladium oxide barrier layer for other semiconductor structures such as a capacitor and transistor structures is also disclosed

The Development of Social Capital in the Collaboration Network of Information Systems Scholars

This study examines the development of social capital in the collaboration network of information systems (IS) scholars over a 33-year period (from 1980 to 2012). Using the co-authorship data from six premier journals (MIS Quarterly, Information Systems Research, Journal of MIS, Journal of the AIS, European Journal of Information Systems, and Information Systems Journal), we analyze the historical trajectory of five aspects of the field\u27s structural social capital: network ties, network configuration, structural holes, growth, and structural cohesion. Our results show that, as a scientific field, the IS community has made significant progress in accumulating social capital. The current IS collaboration network is also comparable in several aspects with networks found in other business disciplines (e.g., management, finance, and marketing). Our study has several important implications for the focus-versus-diversity debate in the IS field. Based on our findings, we offer some recommendations as to how the IS community can increase the field\u27s social capital, and thereby facilitate knowledge creation and innovation

Validity and reliability of the Parental Homework Management Scale

Background: Prior research has shown that parents help their children manage homework (i.e. environment, time, motivation and emotion management), especially in elementary school. However, researchers have not developed and validated a scale focused on those dimensions. Method: The purpose of the present study is to validate the Parental Homework Management Scale (PHMS) for parents of elementary school children in the domain of mathematics. A sample of 2,118 parent-child dyads was split randomly into two groups to conduct the analysis in two stages: (i) exploratory factor analysis on Group 1 and (ii) confi rmatory factor analysis on Group 2. Results: PHMS is comprised of two distinct but related factors (i.e. environment-time and motivation-emotion management). Results further indicated that the PHMS was positively related to homework self-regulation and positive emotions, and negatively related to math achievement. Contrary to expectations, no relationship was found between PHMS and amount of student homework completed. Conclusions: The scale revealed good psychometric quality.Validación y fi abilidad de la escala de gestión de tareas para casa para padres. Antecedentes: investigaciones previas revelaron que los padres ayudan a sus hijos a gestionar las tareas para casa (i.e., el ambiente, el tiempo, la motivación y las emociones), especialmente en la escuela primaria. Sin embargo, la investigación no ha construido y validado una escala enfocada en esas dimensiones. Método: el presente estudio valida el Parental Homework Management Scale (PHMS) para padres de niños de escuela primaria en el dominio de las matemáticas. Una muestra de 2,118 díadas padres-hijos se dividió aleatoriamente en dos grupos para realizar el análisis en dos etapas: (i) análisis factorial exploratorio en el Grupo 1 y (ii) análisis factorial confi rmatorio en el Grupo 2. Resultados: PHMS está compuesto por dos factores distintos pero relacionados (i.e., gestión del ambiente-tiempo y de la motivación-emoción). Los resultados indicaron además que el PHMS se relacionó positivamente con la autorregulación y las emociones positivas en las tareas para casa, y se relacionó negativamente con el rendimiento en matemáticas. Contrario a las expectativas, no se encontró relación entre PHMS y la cantidad de tareas completadas por los estudiantes. Conclusiones: la escala ha revelado una buena calidad psicométrica.This work was supported by Portuguese Foundation for Science and Technology (FCT) and the Portuguese Ministry of Science (UID/PSI/01662/2013). JC was supported by a PhD fellowship from the Portuguese FCT (SFRH/BD/95341/2013)

Amperometric Solid Electrolyte Oxygen Microsensors with Easy Batch Fabrication

An amperometric solid electrolyte oxygen (O2) microsensor using a novel and robust structure has been developed with a detection range of 0.025 to 21 percent of O2 concentration. The microsensor has a simple structure with a sensing area of 1.10 0.99 mm(exp 2), and is operated by applying voltage across the electrodes and measuring the resulting current flow at a temperature of 600 C