4,559 research outputs found
Effects of burying and removing dead leaves from the ground on the development of scab epidemics in an apple organic orchard.
Ascospores produced on scabbed leaves in the leaf litter constitute the primary
inoculum causing scab infections in apple orchards during the year. The trial, carried
out in a commercial organic orchard, permitted to evaluate the effects of the
removal of dead leaves located on the inter-row supplemented by the ploughing in of
the leaves left on the row, on the development of scab epidemics. From the first
recorded contamination to harvest time, lesions on leaves and fruits were counted to
determine reduction in disease incidence and severity, compared with the untreated
plots. Disease severity as a function of the distance from the untreated plot was also
observed, to evaluate the spore dispersal gradient within the orchard. The results
show that the ploughing in and the removal of the litter reduced disease incidence by
62% on leaves, and by almost 82% on fruits to harvest. Moreover, measurements of
the dispersal gradient show that the spores do not disperse, or little, beyond 20m of
the untreated zone
Enabling Personalized Composition and Adaptive Provisioning of Web Services
The proliferation of interconnected computing devices is fostering the emergence of environments where Web services made available to mobile users are a commodity. Unfortunately, inherent limitations of mobile devices still hinder the seamless access to Web services, and their use in supporting complex user activities. In this paper, we describe the design and implementation of a distributed, adaptive, and context-aware framework for personalized service composition and provisioning adapted to mobile users. Users specify their preferences by annotating existing process templates, leading to personalized service-based processes. To cater for the possibility of low bandwidth communication channels and frequent disconnections, an execution model is proposed whereby the responsibility of orchestrating personalized processes is spread across the participating services and user agents. In addition, the execution model is adaptive in the sense that the runtime environment is able to detect exceptions and react to them according to a set of rules
Entangled single-wire NiTi material: a porous metal with tunable superelastic and shape memory properties
NiTi porous materials with unprecedented superelasticity and shape memory
were manufactured by self-entangling, compacting and heat treating NiTi wires.
The versatile processing route used here allows to produce entanglements of
either superelastic or ferroelastic wires with tunable mesostructures. Three
dimensional (3D) X-ray microtomography shows that the entanglement
mesostructure is homogeneous and isotropic. The thermomechanical compressive
behavior of the entanglements was studied using optical measurements of the
local strain field. At all relative densities investigated here ( 25 -
40), entanglements with superelastic wires exhibit remarkable macroscale
superelasticity, even after compressions up to 25, large damping capacity,
discrete memory effect and weak strain-rate and temperature dependencies.
Entanglements with ferroelastic wires resemble standard elastoplastic fibrous
systems with pronounced residual strain after unloading. However, a full
recovery is obtained by heating the samples, demonstrating a large shape memory
effect at least up to 16% strain.Comment: 31 pages, 10 figures, submitted to Acta Materiali
Aided by Adderall: Illicit Use of ADHD Medications by College Students
“I don’t know that many kids that have done coke, none that have tried crack, and only a few that have dropped acid. I can’t even count all of the ones who’ve taken Adderall” (Stice). This statement made in an interview by a freshman art history major at the University of Maryland, College Park, in 2007 effectively highlights a still growing problem among undergraduate students in the United States: the nonmedical use of stimulant medications prescribed to treat Attention Deficit Hyperactivity Disorder (ADHD) as “study aids.” Even as early as 2004, up to twenty percent of college students had used Adderall or Ritalin, both drugs used to treat ADHD, according to a report released by the National Center on Addiction and Substance Abuse (Stice). This phenomenon of abusing prescription stimulant medications is well-documented not only in research literature but also in numerous news articles. A 2009 NPR article documented the increasingly prevalent use of ADHD medications by college students to help them study and included commentary from Martha J. Farah, director at the Center for Cognitive Neuroscience at the University of Pennsylvania, who described the behavior as “worrisome” due to the drugs’ serious side effects and the potential for addiction (Trudeau). In 2012 The New York Times published just a small fraction of the submissions they received after inviting students to share personal accounts of taking prescription medications for academic purposes, and almost all of them were written by high school students or recent graduates (Schwartz). In 2016, CBS News published a story titled “Adderall misuse rising among young adults,” making it clear that this problem has not lessened in the decade or so that has passed since publication of the 2007 article describing the growing trend of “young people taking prescription drug abuse to college” (Kraft; Stice)
Aided by Adderall: Illicit Use of ADHD Medications by College Students
“I don’t know that many kids that have done coke, none that have tried crack, and only a few that have dropped acid. I can’t even count all of the ones who’ve taken Adderall” (Stice). This statement made in an interview by a freshman art history major at the University of Maryland, College Park, in 2007 effectively highlights a still growing problem among undergraduate students in the United States: the nonmedical use of stimulant medications prescribed to treat Attention Deficit Hyperactivity Disorder (ADHD) as “study aids.” Even as early as 2004, up to twenty percent of college students had used Adderall or Ritalin, both drugs used to treat ADHD, according to a report released by the National Center on Addiction and Substance Abuse (Stice). This phenomenon of abusing prescription stimulant medications is well-documented not only in research literature but also in numerous news articles. A 2009 NPR article documented the increasingly prevalent use of ADHD medications by college students to help them study and included commentary from Martha J. Farah, director at the Center for Cognitive Neuroscience at the University of Pennsylvania, who described the behavior as “worrisome” due to the drugs’ serious side effects and the potential for addiction (Trudeau). In 2012 The New York Times published just a small fraction of the submissions they received after inviting students to share personal accounts of taking prescription medications for academic purposes, and almost all of them were written by high school students or recent graduates (Schwartz). In 2016, CBS News published a story titled “Adderall misuse rising among young adults,” making it clear that this problem has not lessened in the decade or so that has passed since publication of the 2007 article describing the growing trend of “young people taking prescription drug abuse to college” (Kraft; Stice)
Optical versus video see-through mead-mounted displays in medical visualization
We compare two technological approaches to augmented reality for 3-D medical visualization: optical and video see-through devices. We provide a context to discuss the technology by reviewing several medical applications of augmented-reality research efforts driven by real needs in the medical field, both in the United States and in Europe. We then discuss the issues for each approach, optical versus video, from both a technology and human-factor point of view. Finally, we point to potentially promising future developments of such devices including eye tracking and multifocus planes capabilities, as well as hybrid optical/video technology
The Cyclic Cutwidth of
In this article the cyclic cutwidth of the -dimensional cube is explored.
It has been conjectured by Dr. Chavez and Dr. Trapp that the cyclic cutwidth of
is minimized with the Graycode numbering. Several results have been found
toward the proof of this conjecture.Comment: 8 pages, 3 figures. Summer Research Experiences for Undergraduates
report from August 2003, with some typos fixe
Antibunched photons emitted by a dc-biased Josephson junction
We show experimentally that a dc biased Josephson junction in series with a high-enough-impedance microwave resonator emits antibunched photons. Our resonator is made of a simple microfabricated spiral coil that resonates at 4.4 GHz and reaches a 1.97kΩ characteristic impedance. The second order correlation function of the power leaking out of the resonator drops down to 0.3 at zero delay, which demonstrates the antibunching of the photons emitted by the circuit at a rate of 6×10^7 photons per second. Results are found in quantitative agreement with our theoretical predictions. This simple scheme could offer an efficient and bright single-photon source in the microwave domain
Making it real: exploring the potential of Augmented Reality for teaching primary school science
The use of Augmented Reality (AR) in formal education could prove a key component in future learning environments that are richly populated with a blend of hardware and software applications. However, relatively little is known about the potential of this technology to support teaching and learning with groups of young children in the classroom. Analysis of teacher-child dialogue in a comparative study between use of an AR virtual mirror interface and more traditional science teaching methods for 10-year-old children, revealed that the children using AR were less engaged than those using traditional resources. We suggest four design requirements that need to be considered if AR is to be successfully adopted into classroom practice. These requirements are: flexible content that teachers can adapt to the needs of their children, guided exploration so learning opportunities can be maximised, in a limited time, and attention to the needs of institutional and curricular requirements
- …