External Pool Research Articles

Public platform with 39,472 exome control samples enables association studies without genotype sharing.

Acquiring a sufficiently powered cohort of control samples matched to a case sample can be time-consuming or, in some cases, impossible. Accordingly, an ability to leverage genetic data from control samples that were already collected elsewhere could dramatically improve power in genetic association studies. Sharing of control samples can pose significant challenges, since most human genetic data are subject to strict sharing regulations. Here, using the properties of singular value decomposition and subsampling algorithm, we developed a method allowing selection of the best-matching controls in an external pool of samples compliant with personal data protection and eliminating the need for genotype sharing. We provide access to a library of 39,472 exome sequencing controls at http://dnascore.net enabling association studies for case cohorts lacking control subjects. Using this approach, control sets can be selected from this online library with a prespecified matching accuracy, ensuring well-calibrated association analysis for both rare and common variants.

Exploring the Role of PI3P in Platelets: Insights from a Novel External PI3P Pool

Phosphoinositides (PIs) play a crucial role in regulating intracellular signaling, actin cytoskeleton rearrangements, and membrane trafficking by binding to specific domains of effector proteins. They are primarily found in the membrane leaflets facing the cytosol. Our study demonstrates the presence of a pool of phosphatidylinositol 3-monophosphate (PI3P) in the outer leaflet of the plasma membrane of resting human and mouse platelets. This pool of PI3P is accessible to exogenous recombinant myotubularin 3-phosphatase and ABH phospholipase. Mouse platelets with loss of function of class III PI 3-kinase and class II PI 3-kinase α have a decreased level of external PI3P, suggesting a contribution of these kinases to this pool of PI3P. After injection in mouse, or incubation ex vivo in human blood, PI3P-binding proteins decorated the platelet surface as well as α-granules. Upon activation, these platelets were able to secrete the PI3P-binding proteins. These data sheds light on a previously unknown external pool of PI3P in the platelet plasma membrane that recognizes PI3P-binding proteins, leading to their uptake towards α-granules. This study raises questions about the potential function of this external PI3P in the communication of platelets with the extracellular environment, and its possible role in eliminating proteins from the plasma.

Experimental Investigations on the Effect of Ultrasonic Field in External Pool Boiling Under Various Operating Pressures

Abstract The augmentation of boiling heat transfer has been a dynamic domain of research for the past several decades due to a wide range of energy intensive applications and, in line, many active and passive methods have been developed. The present study discusses the effect of ultrasonic field of 31 kHz and 40 kHz on the saturated pool boiling of R141b over plain Cu surface at different operating pressures. It was found that the ultrasonic field is more effective at higher operating pressures. The surface superheat reduced by a maximum value of 2.6 °C with the application of 31 kHz ultrasonic field in comparison to the pool boiling without ultrasonic field application for +30 kPa(g) operating pressure at lower heat flux level of 113 kW/m2. The maximum augmentation in heat transfer coefficient was calculated as 37.1% and 11.4% for frequency of 31 kHz and 40 kHz, respectively, with respect to the no ultrasonic field condition at +30 kPa(g) for lower heat flux level of 113 kW/m2. The Nusselt number was found to be increasing in the sub-atmospheric as well as the pressurized operating pressure range. In comparison to the boiling without application of ultrasonic field, the maximum improvement in Nusselt number was noted as 25.3% at 31 kHz frequency of ultrasonic field and +30 kPa(g) operating conditions. This study suggests the use of lower frequency range of ultrasonic field in the presence of higher operating pressures for higher augmentation in saturated pool boiling.

Experimental comparison on condensation and evaporation outside double-side enhanced horizontal tubes

Experimental investigations of the condensation and evaporation of R410A on the outside of two double-side enhanced heat transfer tubes were conducted, and the tube performance was compared with that of a smooth copper tube. The research object consisted of a smooth tube with a length of 2000 mm and an outer diameter of 25.4 mm and two double-side enhanced tubes of the same size. The evaporation experiments were run under the following conditions: the evaporation saturation temperature was 7°C, water inlet temperature was 8°C–18°C, and water flow rate was 0.6–1.6 m3/h. The condensation experiments were run under the following conditions: the saturation temperature was 35°C, water inlet temperature was 21°C–30°C, and water flow rate was 0.4–1.6 m3/h. During the data processing, the heat transfer coefficient of the water side was obtained using the Gnielinski-Wilson method, and that of the refrigerant side was obtained using the thermal resistance separation method. The effect of the surface structure on the heat transfer performance was analyzed, and a strengthening measure was proposed. The experimental results indicate that the evaporation heat transfer coefficients outside the smooth tube increased with the raise of the inlet water temperature, while the double-side enhanced tubes decreased; both the condensation heat transfer coefficients outside the smooth tube and the enhanced tubes increased with the increase of the water flow rate. Due to the different type of enhanced tube ribs, tube #3 surface structure is more conducive to the formation of vaporization core, which is about 30% higher than the outer heat transfer coefficient of tube #2. It is more in line with the requirements of strengthening horizontal single tube external pool boiling heat transfer. In the condensation experiment, the condensation heat transfer coefficients outside the smooth tube increased with the raise of the inlet water temperature, while the double enhanced tubes decreased; both the condensation heat transfer coefficients outside the smooth tube and the enhanced tubes increased with the increase of the water flow rate. With the analysis of the rib structure, the outer surface structure of tube #2 has stronger drainage capacity, and the external average condensation heat transfer coefficient is about 7% higher than that of tube #3, which is more in line with the requirements of condensing heat transfer outside the single tube.

STH/CFD Coupled Simulation of the Protected Loss of Flow Accident in the CIRCE-HERO Facility

The paper presents the application of a coupling methodology between Computational Fluid Dynamics (CFD) and System Thermal Hydraulic (STH) codes developed at the University of Pisa. The methodology was applied to the CIRCE-HERO facility in order to reproduce the recently performed experimental conditions simulating a Protected Loss Of Flow Accident (PLOFA). The facility consists of an internal loop, equipped with a fuel pin simulator and a steam generator, and an external pool. In this coupling application, the System code RELAP5 is adopted for the simulation of the internal loop while the CFD code ANSYS Fluent is used for the sake of simulating the pool. The connection between the two addressed domains is provided at the inlet and outlet section of the internal loop; a thermal coupling is also performed in order to reproduce the observed thermal stratification phenomenon. The obtained results are promising and a good agreement was obtained for both the mass flow rates and temperature measurements. Capabilities and limitations of the adopted coupling technique are discussed in the present paper also providing suggestions for improvements and developments to be achieved in the frame of future applications.

Bubble nucleators to enhance external pool boiling from the bottom row of a tube bundle

The influence of vapour bubbles impacting on boiling heat transfer surfaces is examined. Passive nucleators based on boiling heat transfer were used to create gas bubbles with varying properties that impinged upon two horizontal tubes above. Two nucleator devices were compared: a microscale nichrome wire nucleator, and a hollow tube nucleator situated below a column of cylinders with uniform heat flux. Nucleators significantly enhanced the heat transfer coefficient of the lower tube in the column, which was most pronounced at low heat fluxes due to the early activation of potential nucleation sites by the bubbly flow carried from the nucleator by buoyancy. Nucleator augmentation of heat transfer coefficient on the tube above was insensitive to nucleator heat flux once nucleate boiling was established and, for the nucleator geometries tested, only weakly dependent on nucleator geometry and vapour generation rate.

Density‐dependent mechanisms regulate spore formation in the diatom Chaetoceros socialis

AbstractResting stages are reported for several unicellular eukaryotes including diatoms that can produce spores or resting cells. These stages represent a repository of diversity in sediments but the factors that induce their formation are elusive. We investigated spore formation in the marine diatom Chaetoceros socialis. Our results confirm that nitrogen starvation is an effective experimental trigger for spore formation. However, we observed that spores are also produced when the external pool of nutrients is not limiting, and by using a semicontinuous setup, we could show that they appear only when cell density is high. The presence of a chemical cue mediating spore formation was supported by experiments carried out incubating cells with culture media conditioned by both healthy and lysed cells. These findings shed new light on the mechanisms that regulate the transition between life cycle stages and represent an experimental baseline for the identification of the signaling molecules.

Rapid Replacement of Acinetobacter baumannii Strains Accompanied by Changes in Lipooligosaccharide Loci and Resistance Gene Repertoire.

The population structure of health care-associated pathogens reflects patterns of diversification, selection, and dispersal over time. Empirical data detailing the long-term population dynamics of nosocomial pathogens provide information about how pathogens adapt in the face of exposure to diverse antimicrobial agents and other host and environmental pressures and can inform infection control priorities. Extensive sequencing of clinical isolates from one hospital spanning a decade and a second hospital in the Cleveland, OH, metropolitan area over a 3-year time period provided high-resolution genomic analysis of the Acinetobacter baumannii metapopulation. Genomic analysis demonstrated an almost complete replacement of the predominant strain groups with a new, genetically distinct strain group during the study period. The new group, termed clade F, differs from other global clone 2 (GC2) strains of A. baumannii in several ways, including its antibiotic resistance and lipooligosaccharide biosynthesis genes. Clade F strains are part of a large phylogenetic group with broad geographic representation. Phylogenetic analysis of single-nucleotide variants in core genome regions showed that although the Cleveland strains are phylogenetically distinct from those isolated from other locations, extensive intermixing of strains from the two hospital systems was apparent, suggesting either substantial exchange of strains or a shared, but geographically restricted, external pool from which infectious isolates were drawn. These findings document the rapid evolution of A. baumannii strains in two hospitals, with replacement of the predominant clade by a new clade with altered lipooligosaccharide loci and resistance gene repertoires.IMPORTANCE Multidrug-resistant (MDR) A. baumannii is a difficult-to-treat health care-associated pathogen. Knowing the resistance genes present in isolates causing infection aids in empirical treatment selection. Furthermore, knowledge of the genetic background can assist in tracking patterns of transmission to limit the spread of infections in hospitals. The appearance of a new genetic background in A. baumannii strains with a different set of resistance genes and cell surface structures suggests that strong selective pressures exist, even in highly MDR pathogens. Because the new strains have levels of antimicrobial resistance similar to those of the strains that were displaced, we hypothesize that other features, including host colonization and infection, may confer additional selective advantages and contribute to their increased prevalence.

Externally held water – a key factor for hair lichens in boreal forest canopies

Lichens hold water inside (internal pool) and outside their body (external pool). Yet, external pool size is not known in hair lichens dominating boreal forest canopies. Here we quantify morphologi ...

Trophic dynamics of a simple model ecosystem

We have constructed a model of community dynamics that is simple enough to enumerate all possible food webs, yet complex enough to represent a wide range of ecological processes. We use the transition matrix to predict the outcome of succession and then investigate how the transition probabilities are governed by resource supply and immigration. Low-input regimes lead to simple communities whereas trophically complex communities develop when there is an adequate supply of both resources and immigrants. Our interpretation of trophic dynamics in complex communities hinges on a new principle of mutual replenishment, defined as the reciprocal alternation of state in a pair of communities linked by the invasion and extinction of a shared species. Such neutral couples are the outcome of succession under local dispersal and imply that food webs will often be made up of suites of trophically equivalent species. When immigrants arrive from an external pool of fixed composition a similar principle predicts a dynamic core of webs constituting a neutral interchange network, although communities may express an extensive range of other webs whose membership is only in part predictable. The food web is not in general predictable from whole-community properties such as productivity or stability, although it may profoundly influence these properties.

Detection of Weld Pool Width during Strong Arc Disturbance Environment

Detecting the weld pool width is prerequisite to control the welding quality. However, in an arc welding process, it is difficult to obtain a clear image of weld pool due to strong arc disturbance. A method is proposed to lessen the arc disturbance and obtain the width of a weld pool. A camera was used to capture the weld pool images during the arc welding process. The frequency domain filter combined with spatial processing algorithms were used to depress the noises in the pool image. During arc welding, the weld pool was in a liquid state and showed specular reflection due to the arc light effects. Because of the specular reflection, edges of the weld pool exhibited different brightness from that of the internal weld pool where a camera hangs. According to this phenomenon, it was easy to recognize the outlines of the internal and external weld pool. After the image noise of the weld pool was eliminated by an image filtering algorithm, then the line scanning on the image was carried out. It was crystal-clear that the external edge and internal edge demonstrate different grey levels. Therefore the method could be utilized to identify and extract the internal weld pool width and external weld pool width.

Organizational and individual change: a case study

PurposeThis article aims to focus on a program that was designed to support a major international specialist publisher during a global organizational change program and to support individuals with their personal transitions.Design/methodology/approachThe program derived from a decision to fully embrace the possibilities of electronic publishing and workflow systems. The identification of live cases for change enabled complete workplace teams and units to develop skills and understanding in implementing and experiencing change in parallel with the introduction of new practices. After initial piloting in two business units, a program model emerged comprising two levels of workshops (Leading and implementing change and Experiencing change) and pre‐event and post‐event webinars with follow‐through activity including 1:1 and team coaching. Flexibility was retained to be adaptable to the specific requirements of each business unit and case for change.FindingsThe implementation of new working practices and procedures at senior levels was greatly aided by an overall approach based on the active inclusion of all levels of staff. The incorporation of workshops on experiencing change provided models to explain the process and coping strategies that minimized the less agreeable emotional elements of change while enhancing the successful transition to a new working reality.Practical implicationsThe context of the organization extended the impact of the change program beyond direct employees – a large external pool of authors, contributors and editors would be affected by process transformation. In addition to supporting the global change program, the approach taken in the cases for change has provided those involved with both theoretical and practical understanding of the psychological impact of individual transitions as well as the organizational challenges of change management.Originality/valueThe article shows that the “hands on” understanding enabled the program to actively involve and consult with those beyond the organization's wall and implement changes while remaining mindful of impact on individuals.

Alcohol Dependence Figures in the Swiss General Population: A Sisyphean Challenge for Epidemiologists

Background: Research in Switzerland and elsewhere calls for valid estimations of alcohol dependence figures at the population level. As none of the methodologies developed for this purpose has proven to possess higher validity over others, this study follows the idea of methodological triangulation and compares estimates to assess their convergence. Methods: This study considers 6 standard methodological approaches to derive 17 estimates for alcohol dependence in the Swiss general population. Results: Estimates from statistics on cirrhosis mortality and from the application of external pool estimates agree with the central tendency of adjusted estimates derived using standard alcohol-related screening tools in population surveys. The number of alcohol-dependent individuals living in Switzerland is expected to be close to 250,000 (i.e. approximately 3.9% of the population aged 15 or older). Conclusion: Due to variations in estimates, it is difficult to report consistent figures for alcohol dependence at the general population level in Switzerland. Nonetheless, observation of an unambiguous central tendency and the convergence of estimates support their validity.

Effects of elevated CO2 on the red seaweed Gracilaria lemaneiformis (Gigartinales, Rhodophyta) grown at different irradiance levels

Zou D. and Gao K. 2009. Effects of elevated CO2 on the red seaweed Gracilaria lemaneiformis (Gigartinales, Rhodophyta) grown at different irradiance levels. Phycologia 48: 510–517. DOI: 10.2216/08-99.1.The red seaweed Gracilaria lemaneiformis (Bory) Weber-van Bosse (Gigartinales, Rhodophyta) from Nanao Island, Shantou, China, was cultured at 370 and 700 µl l−1 CO2 in aeration and at intermediate (160 µmol photons m−2 s−1) and low (30 µmol photons m−2 s−1) irradiance levels in order to examine the influences of the elevated atmospheric CO2 concentrations on growth, photosynthetic performance and some biochemical components in this commercially important species. Relative growth rate (RGR) was significantly higher in G. lemaneiformis thalli grown using CO2-enriched air with respect to nonenriched air when the algae were subjected to intermediate irradiance. However, RGR was similar between these two CO2 treatments when the algae were grown under the low-irradiance condition. Extra CO2 in the culture decreased phycobiliprotein (PB, including phycoerythrin, PE, and phycocyanin, PC) contents of G. lemaneiformis thalli at the higher growth irradiance. However, chlorophyll a (Chl a) and soluble protein contents were unchanged by the CO2 levels in culture. Both PB and Chl a contents were higher in G. lemaneiformis thalli grown at the lower irradiance than at the higher irradiance, regardless of the CO2 levels in culture. The parameters for photosynthetic responses to irradiance and inorganic carbon were mostly not altered with the increase of CO2 concentrations in culture. However, light-saturated photosynthetic rates (Pmax) and apparent carboxylating efficiencies (ACE), expressed per unit Chl a, were significantly higher in algae grown at the intermediate irradiance compared to the low irradiance. Photosynthetic rate was reduced by an increase in pH of seawater from 8.2 to 9.1, and it was also strongly inhibited by the external carbonic anhydrase inhibitor acetazolamide (AZ) in G. lemaneiformis thalli grown at each CO2 and irradiance condition. Moreover, pH compensation points were not affected by the growth conditions. These results suggested that G. lemaneiformis under both growth conditions had a similar capacity of the photosynthetic utilization of external pool in seawater. However, ACE decreased in G. lemaneiformis thalli grown at the low irradiance with respect to the higher irradiance implied that the transport of Ci towards Rubisco within the cell was weakened. Taken together, the data showed that an increase of CO2 was less effective on G. lemaneiformis than the irradiance levels. We concluded that CO2 affected photosynthesis and growth performance when light was not the limiting factor.

Measuring Information Technology Spillovers

The measurement of the impact of IT spillovers on productivity is an important emerging area of research. Studies of IT spillovers often adopt a “production function” approach commonly used for measuring R&D spillovers, in which an external pool of IT investment is modeled using weighted measures of the IT investments of other firms, industries, or countries. We show that when using this approach, measurement error in a firm's own IT inputs can exert a significant upward bias on estimates of social returns to IT investment. This problem is particularly severe for IT spillovers because of the high levels of measurement error in most available IT data. The presence of the bias term can be demonstrated by using instrumental variable techniques to remove the effects of measurement error in a firm's own IT inputs. Using panel data on IT investment, we show that measurement error corrected estimates of IT spillovers are 40% to 90% lower than uncorrected estimates. This bias term is increasing in the correlation between the IT pool and firms' own IT investment. Therefore, estimates from models of spillover pools are less sensitive to the issues identified in this paper when the spillover paths minimize the correlation between a firm's own IT investment and the constructed external IT pool. Implications for researchers, policy makers, and managers are discussed.

Measuring Information Technology Spillovers

The measurement of the impact of IT spillovers on productivity is an important emerging area of research. Studies of IT spillovers often adopt a ‘production function’ approach commonly used for measuring R&D spillovers, in which an external pool of IT investment is modeled using weighted measures of the IT investments of other firms, industries, or countries. We show that when using this approach, measurement error in a firm’s own IT inputs can create a significant upward bias on the estimated social returns to IT investment. This problem is particularly severe for estimating IT spillovers due to the high levels of measurement error in most available IT data. This bias can be addressed by using instrumental variable techniques to correct the measurement error in a firm’s own IT inputs. Using panel data on IT investment, we show that measurement error corrected estimates of IT spillovers are 40 to 90% lower than uncorrected estimates. This bias term is increasing in the correlation between the IT pool and firms’ own IT investment. Therefore, when instruments are not available, the use of fine-grained data on transmission paths can be an effective solution because IT spillover channels are more likely than R&D spillover channels to cut across industry boundaries, minimizing the correlation between a firm’s own IT investment and the constructed external IT pool. Implications for researchers, policy makers, and managers are discussed.

Toward databases mining: Pre-processing collected data

This paper presents a new means of selecting quality data for mining multiple data sources. Traditional data-mining strategies obtain necessary data from internal and external data sources and pool all the data into a huge homogeneous dataset for discovery. In contrast, our data-mining strategy identifies quality data from (internal and external) data sources for a mining task. A framework is advocated for generating quality data. Experimental results demonstrate that application of this new data collecting technique can not only identify quality data, but can also efficiently reduce the amount of data that must be considered during mining.

Call for Nominations: Editorial Board and External Reviewer Pool, Child Maltreatment: The Journal of the American Professional Society on the Abuse of Children

Call for Nominations: Editorial Board and External Reviewer Pool, Child Maltreatment: The Journal of the American Professional Society on the Abuse of Children

Photosynthesis might be limited by light, not inorganic carbon availability, in three intertidal Gelidiales species.

• The interaction between incident photon fluence density (PFD) and dissolved inorganic carbon (DIC) availability on photosynthesis is reported for three species of Gelidiales (Rhodophyta) from the Canary Islands. • Photosynthetic O2 evolution in response to both DIC concentration and PFD, and external carbonic anhydrase activity were measured in thalli of Gelidium canariensis, Gelidium arbuscula and Pterocladiella capillacea maintained in a controlled-environment room. • No detectable external carbonic anhydrase activity, high sensitivity to alkaline pH and moderate values of photosynthetic conductance for DIC indicated that the three species had a low capacity for using the external pool of HCO3 - ; therefore photosynthetic rates were dependent on CO2 availability. The seawater concentration of DIC was insufficient to saturate photosynthesis at high PFD; photosynthesis vs PFD was not affected by DIC concentration at 0.07-0.04mol O2 mol-1 photon. ANOVA revealed that incident PFD had a greater effect than DIC availability on photosynthesis rates in G. canariensis. • Photosynthesis is probably limited by incident light rather than DIC concentration despite the apparent low affinity for HCO3 - in G. canariensis, G. arbuscula and P. capillacea in their natural habitats.

Physiological Functioning of Carbonic Anhydrase in the Hydrothermal Vent Tubeworm Riftia Pachyptila.

On the basis of our experiments, it is clear that carbonic anhydrase (CA) plays an important role in the CO2-concentrating mechanisms in Riftia pachyptila. Plume tissue from freshly collected animals had the highest CA activity, 253.7 +/- 36.0 {mu}mol CO2 min-1 g-1 wet wt, and trophosome activity averaged 109.4 +/- 17.9 {mu}mol CO2 min-1 g-1 wet wt. Exposure of living worms to ethoxyzolamide, a carbonic anhydrase inhibitor, resulted in a 99% decrease in CA activity (from 103.9 +/- 38.6 to 0.7 +/- 0.2 {mu}mol CO2 min-1 g-1 wet wt in the plume tissue and 57.6 +/- 17.9 to 0.04 +/- 0.11 {mu}mol CO2 min-1 g-1 wet wt in the trophosome) and essentially a complete cessation of {Sigma}CO2 uptake. High concentrations of CA appear to facilitate the equilibration between inorganic carbon (Ci) in the external and internal environments, greatly enhancing the diffusion of CO2 into the animal. In summary, R. pachyptila demonstrates very effective acquisition of inorganic carbon from the environment, thereby providing the symbionts with large amounts of CO2. This effective acquisition is made possible by three factors: extremely effective pH regulation, a large external pool of CO2, and, described in this paper, high levels of carbonic anhydrase.