1,295 research outputs found
Liquid Scintillator Time Projection Chamber Concept
Results are presented from a small-scale experiment to investigate the use of
room temperature organic liquid scintillators as the active medium for a time
projection chamber (TPC). The optical properties of liquid scintillators have
long been known, but their ability to transport charge has remained, until now,
largely untested. The idea of using room temperature liquids as an active
medium for an ionisation chamber was first presented in \cite{EnglerTMS}. Since
then the range of liquid scintillators available has been greatly developed. We
present successful transport of ionization charges in a selection of both, pure
organic liquid solvents and liquid scintillator cocktails over 20mm using a
variety of electric drift field strengths. The target of this research is to
offer a cost effective alternative to liquid noble gas detectors in neutrino
physics.Comment: 6 pages, 5 figures, submitted to Proceedings 12th Pisa Meeting on
Advanced Detectors, La Biodola, Isola d'Elba, Ital
Wearing a bike helmet leads to less cognitive control, revealed by lower frontal midline theta power and risk indifference
A recent study claims that participants wearing a bike helmet behave riskier in a computer-based risk task compared to control participants without a bike helmet. We hypothesized that wearing a bike helmet reduces cognitive control over risky behavior. To test our hypothesis, we recorded participants' EEG brain responses while they played a risk game developed in our laboratory. Previously, we found that, in this risk game, anxious participants showed greater levels of cognitive control as revealed by greater frontal midline theta power, which was associated with less risky decisions. Here, we predicted that cognitive control would be reduced in the helmet group, indicated by reduced frontal midline theta power, and that this group would prefer riskier options in the risk game. In line with our hypothesis, we found that participants in the helmet group showed significantly lower frontal midline theta power than participants in the control group, indicating less cognitive control. We did not replicate the finding of generally riskier behavior in the helmet group. Instead, we found that participants chose the riskier option in about half of trials, no matter how risky the other option was. Our results suggest that wearing a bike helmet reduces cognitive control, as revealed by reduced frontal midline theta power, leading to risk indifference when evaluating potential behaviors
What you give is what you get : payment of one randomly selected trial induces risk-aversion and decreases brain responses to monetary feedback
In economic studies, it is standard practice to pay out the reward of only one randomly selected trial (pay-one) instead of the total reward accumulated across trials (pay-all), assuming that both methods are equivalent. We tested this assumption by recording electrophysiological activity to reward feedback from participants engaged in a decision-making task under both a pay-one and a pay-all condition. We show that participants are approximately 12% more risk averse in the pay-one condition than in the pay-all condition. Furthermore, we observed that the electrophysiological response to monetary rewards, the reward positivity, is significantly reduced in the pay-one condition relative to the pay-all condition. The difference of brain responses is associated with the difference in risky behavior across conditions. We concluded that the two payment methods lead to significantly different results and are therefore not equivalent
Tracking movements of Athene owls: the application of North American experiences to Europe
Seguimiento de los desplazamiento de los mochuelos del género Athene: aplicación de las experiencias norteamericanas a Europa
Migración y dispersión son procesos importantes desde el punto de vista de la ecología y la evolución, y entenderlos es un requisito importante para los programas de conservación de las especies. El mochuelo de madriguera, Athene cunicularia, el equivalente norteamericano del mochuelo europeo, A. noctua, es migratorio en las zonas septentrionales de su área de acción. En Canadá sus poblaciones han disminuido de forma notoria, y se han clasificado como amenazadas. Se han estudiado los desplazamientos del mochuelo de madriguera utilizando el anillado, la telemetría VHF, los isótopos estables, la genética (ADN), los geolocalizadores y los transmisores por satélite. Los geolocalizadores y los transmisores por satélite proporcionan la información más fiable sobre las migraciones, pero para su buen funcionamiento dependen de la exposición a la luz solar, que es limitada en el caso de las rapaces nocturnas. Los hallazgos de animales anillados, y los flujos migratorios invernales del mochuelo común hacia España, incluyendo las Islas Baleares, indican que pueden estarse dando desplazamientos migratorios. Un estudio mediante isótopos estables podría determinar si entre los mochuelos que invernan en el sur de Europa, se incluyen mochuelos del norte de Europa.
Palabras clave: Athene, Desplazamientos, Migración, Dispersión, Técnicas.Migration and dispersal are important ecological and evolutionary processes and understanding them is a requirement for species conservation efforts. Burrowing owl, Athene cunicularia, the North American equivalent of little owl, A. noctua, is migratory in the northern parts of its range. In Canada their populations have declined dramatically and are classified as endangered. Movements of burrowing owls have been studied using banding (ringing), VHF telemetry, stable isotopes, genetics (DNA), geolocators and satellite transmitters. Geolocators and satellite transmitters provide the most reliable information about migrations but to operate successfully they are both dependent upon exposure to sunlight, which can be limited for nocturnal owls. Ringing encounters and winter influxes of little owls into Spain, including the Balearic Islands, indicate that some migration movement may be
occurring. A stable isotope study could determine if wintering owls in southern Europe includes owls originating in northern Europe.
Key words: Athene, Movements, Migration, Dispersal, Techniques.Seguimiento de los desplazamiento de los mochuelos del género Athene: aplicación de las experiencias norteamericanas a Europa
Migración y dispersión son procesos importantes desde el punto de vista de la ecología y la evolución, y entenderlos es un requisito importante para los programas de conservación de las especies. El mochuelo de madriguera, Athene cunicularia, el equivalente norteamericano del mochuelo europeo, A. noctua, es migratorio en las zonas septentrionales de su área de acción. En Canadá sus poblaciones han disminuido de forma notoria, y se han clasificado como amenazadas. Se han estudiado los desplazamientos del mochuelo de madriguera utilizando el anillado, la telemetría VHF, los isótopos estables, la genética (ADN), los geolocalizadores y los transmisores por satélite. Los geolocalizadores y los transmisores por satélite proporcionan la información más fiable sobre las migraciones, pero para su buen funcionamiento dependen de la exposición a la luz solar, que es limitada en el caso de las rapaces nocturnas. Los hallazgos de animales anillados, y los flujos migratorios invernales del mochuelo común hacia España, incluyendo las Islas Baleares, indican que pueden estarse dando desplazamientos migratorios. Un estudio mediante isótopos estables podría determinar si entre los mochuelos que invernan en el sur de Europa, se incluyen mochuelos del norte de Europa.
Palabras clave: Athene, Desplazamientos, Migración, Dispersión, Técnicas
SCC characterization of AL-Li-Cu-x Alloys
In the past several decades many Al-Li-X alloys have been studied to understand the fracture properties due to its superior specific strength and modulus over the currently dominated 2024 & 7075 type aircraft structural alloys. It is also observed that their stress corrosion resistance is also good in the peak aged condition depending on the (Li/Cu) ratio. To understand its behavior with respect to its heat treatment, a systematic collection of data is required from the published literature.
We have collected such systematic data for three alloys from the early 1980’s on Al-3Li, Al-2Li-3Cu and Al-1.5Li-4.5Cu, all with 0.12Zr to keep the grain structure predominantly un-recrystalized. Such alloys were tested in the S-T direction in 3.5%NaCl solution to obtain the plateau velocities (da/dt) and threshold KIscc. It is observed that in all the alloys, (da/dt) decreased with aging heat treatment time, the decrease increased with (Li/Cu) ratio. This decrease is interpreted in terms of the degree of anodic dissolution of the grain boundary precipitates. The results are compared with theSCCbehavior of 7050 and 2024 alloys. Additional data where reversion aging treatment was given shows that grain boundary precipitates play an important role in theSCCbehavior. The overall trend in theSCCbehavior is discussed in light of the current understanding of the aluminum alloy behavior in terms of anodic dissolution and the role of hydrogen
Home range and habitat use of little owl (athene noctua) in an agricultural landscape in coastal catalonia, Spain
In recent decades agricultural landscapes in Catalonia have undergone a profound transformation as in most of Europe. Reforestation and urban development have reduced farmland and therefore the availability of suitable habitat for some bird species such as the little owl (Athene noctua). The outskirts of the city of Mataró by the Mediterranean Sea exemplify this landscape change, but still support a population of little owl where agriculture is carried out. Three resident little owls were monitored with telemetry weekly from November 2007 until the beginning of August 2008 in this suburban agricultural landscape. Mean home range ± SD was 10.9 ± 5.5 ha for minimum convex polygon (MCP100) and 7.4 ± 3.8 ha for Kernel 95% probability function (K95). Home ranges of contiguous neighboring pairs overlapped 18.4% (MCP100) or 6% (K95). Home range varied among seasons reaching a maximum between March and early August but always included the nesting site. Small forested patches were associated with roosting and nesting areas where cavities in carob trees (Ceratonia siliqua) were important. When foraging in crop fields, the owls typically fed where crops had recently been harvested and replanted. All three owls bred successfully
Nurses’ attitudes towards hospitalized older adults in a tertiary care setting in Ghana
Introduction: The increasing population of older adults and rapid increases in co- morbidities globally has necessitated the need for a healthcare delivery system that meets the multifaceted needs of the growing population of older adults. Concurrent with these rising complex health needs is the importance of positive, non-judgmental attitudes of health services providers towards older adults. Moreover, this is particu-larly important in the nursing profession, given nurses\u27 significant and crucial roles in healthcare settings.
Aim: The study aimed to evaluate nurses’ attitudes towards older adults in a tertiary hospital in Ghana.
Design: It employed a descriptive cross-sectional quantitative design.
Method: Data were collected from 160 registered adult medical and surgical ward nurses using the Ageism Attitude Scale (AAS).
Results: Findings indicated that more than half of the participants had a diploma in gen-eral nursing. None of the nurses surveyed specialized in the care of older adults, and the mean age of participants was 30.14 (3.75) (minimum 24 and maximum 42 years). Female nurses had more positive attitudes than their male counterparts. Although the surveyed nurses reported a somewhat positive attitude towards older adults, there was no correlation between nurses\u27 education levels and positive attitudes
Home range and habitat use of little owl (Athene noctua) in an agricultural landscape in coastal Catalonia, Spain
Área de campeo y uso del hábitat del mochuelo europeo (Athene noctua) en un paisaje agrícola de la costa de Cataluña, España
El paisaje agrícola en Cataluña ha sufrido una profunda transformación en las últimas décadas, tal y como ha ocurrido en gran parte de Europa. La reforestación y especialmente el desarrollo urbanístico han reducido las tierras agrícolas y con ello se ha perdido hábitat adecuado para especies como el mochuelo europeo (Athene noctua). Los alrededores de la ciudad de Mataró, a orillas del Mar Mediterráneo, son un buen ejemplo de este cambio, pero todavía acogen una población de mochuelos allí donde se da actividad agrícola. Entre noviembre de 2007 y principios de agosto de 2008 se siguieron semanalmente con telemetría tres mochuelos residentes en este entorno agrícola periurbano. La media del área de campeo ± DE estimada con el polígono convexo mínimo (MCP100) fue de 10,9 ± 5,5 ha, y de 7,4 ± 3,8 ha, con el estimador de Kernel 95% (K95). Las áreas de campeo de las parejas vecinas se solapaban un 18,4% (MCP100) o un 6% (K95). Las áreas de campeo entre temporadas variaron a lo largo del seguimiento y llegaron a un máximo entre marzo y principios de agosto, aunque éstas siempre albergaron la zona del nido. Las pequeñas manchas arboladas se asociaron a áreas de reposo y nidificación, donde las cavidades naturales de los algarrobos (Ceratonia siliqua) eran importantes. Cuando los mochuelos se detectaron en los campos, fue en cultivos recién cosechados o replantados. Los tres mochuelos criaron con éxito.
Palabras clave: Mochuelo europeo, Athene noctua, Telemetría, Conservación, Área vital, Área de campeo, Uso del hábitat, Paisaje agrícola.In recent decades agricultural landscapes in Catalonia have undergone a profound transformation as in most of Europe. Reforestation and urban development have reduced farmland and therefore the availability
of suitable habitat for some bird species such as the little owl (Athene noctua). The outskirts of the city of Mataró by the Mediterranean Sea exemplify this landscape change, but still support a population of little owl
where agriculture is carried out. Three resident little owls were monitored with telemetry weekly from November 2007 until the beginning of August 2008 in this suburban agricultural landscape. Mean home range ± SD was
10.9 ± 5.5 ha for minimum convex polygon (MCP100) and 7.4 ± 3.8 ha for Kernel 95% probability function (K95). Home ranges of contiguous neighboring pairs overlapped 18.4% (MCP100) or 6% (K95). Home range
varied among seasons reaching a maximum between March and early August but always included the nesting site. Small forested patches were associated with roosting and nesting areas where cavities in carob trees
(Ceratonia siliqua) were important. When foraging in crop fields, the owls typically fed where crops had recently been harvested and replanted. All three owls bred successfully.
Key words: Little owl, Athene noctua, Telemetry, Conservation, Home range, Habitat use, Agricultural landscapeÁrea de campeo y uso del hábitat del mochuelo europeo (Athene noctua) en un paisaje agrícola de la costa de Cataluña, España
El paisaje agrícola en Cataluña ha sufrido una profunda transformación en las últimas décadas, tal y como ha ocurrido en gran parte de Europa. La reforestación y especialmente el desarrollo urbanístico han reducido las tierras agrícolas y con ello se ha perdido hábitat adecuado para especies como el mochuelo europeo (Athene noctua). Los alrededores de la ciudad de Mataró, a orillas del Mar Mediterráneo, son un buen ejemplo de este cambio, pero todavía acogen una población de mochuelos allí donde se da actividad agrícola. Entre noviembre de 2007 y principios de agosto de 2008 se siguieron semanalmente con telemetría tres mochuelos residentes en este entorno agrícola periurbano. La media del área de campeo ± DE estimada con el polígono convexo mínimo (MCP100) fue de 10,9 ± 5,5 ha, y de 7,4 ± 3,8 ha, con el estimador de Kernel 95% (K95). Las áreas de campeo de las parejas vecinas se solapaban un 18,4% (MCP100) o un 6% (K95). Las áreas de campeo entre temporadas variaron a lo largo del seguimiento y llegaron a un máximo entre marzo y principios de agosto, aunque éstas siempre albergaron la zona del nido. Las pequeñas manchas arboladas se asociaron a áreas de reposo y nidificación, donde las cavidades naturales de los algarrobos (Ceratonia siliqua) eran importantes. Cuando los mochuelos se detectaron en los campos, fue en cultivos recién cosechados o replantados. Los tres mochuelos criaron con éxito.
Palabras clave: Mochuelo europeo, Athene noctua, Telemetría, Conservación, Área vital, Área de campeo, Uso del hábitat, Paisaje agrícola
Pre-exposure embrittlement of sensitized alumimium-magnesium alloy, 5083-H116
Environment-sensitive fracture of aluminum-magnesium alloys containing above ~3 wt% magnesium historically has been considered under anodic-dissolution control. Information from more recent studies, however, suggests a hydrogen-related process is also often involved. Further evidence supporting the involvement of a hydrogen-related process of during Intergranular stress corrosion cracking (IGSCC) will be presented using information gleaned from smooth and pre-cracked test specimens, previously sensitized over a range of temperatures in both ‘dry’ and ‘wet’ conditions and then subjected to rising-load testing in a range of environments. A detailed evaluation of the IGSCC using X-ray computed tomography to provide 3-D images and ultra-high-resolution electron microscopy to characterize selected regions within intergranular stress corrosion cracks enables mechanistic insights
Initiation and final failure via environmentally assisted cracking in high strength aluminium
Environmentally assisted cracking (EAC) is particularly important to understand and control in high strength aluminium used in engineering applications as moist air provides a suitable environment to assist cracking in these materials. Propagation of EAC has been widely investigated but initiation has been difficult to follow due to it’s stochastic nature. We show that time-lapse 3D imaging using X-ray computed tomography offers a way to survey large surface areas whilst maintaining site specific high resolution information giving new insights into this process. In addition the final failure of these materials occurs when the environmentally assisted cracks of intergranular or transgranular type grow to a critical length from the initiation sites. We show through mechanical testing assessment and high resolution fractography that the rapid fracture that follows is also assisted by the environment leading to reduced ductility during the final failure.
Examples from AA5083-H131 and AA7085-T7651 are shown which appear to show the same general behaviour. Round dog bone specimens prepared in the Short Transverse direction were subjected to slow strain rate testing (SSRT) at different strain rates and in different environments. Samples were also pre-exposed to different environments to introduce small corrosion sites to act as ‘realistic’ stress raisers in the specimens
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