6,579 research outputs found
Graphene tests of Klein phenomena
Graphene is characterized by chiral electronic excitations. As such it
provides a perfect testing ground for the production of Klein pairs
(electron/holes). If confirmed, the standard results for barrier phenomena must
be reconsidered with, as a byproduct, the accumulation within the barrier of
holes.Comment: 8 page
Tuning the magnetic and structural phase transitions of PrFeAsO via Fe/Ru spin dilution
Neutron diffraction and muon spin relaxation measurements are used to obtain
a detailed phase diagram of Pr(Fe,Ru)AsO. The isoelectronic substitution of Ru
for Fe acts effectively as spin dilution, suppressing both the structural and
magnetic phase transitions. The temperature of the tetragonal-orthorhombic
structural phase transition decreases gradually as a function of x. Slightly
below the transition temperature coherent precessions of the muon spin are
observed corresponding to static magnetism, possibly reflecting a significant
magneto-elastic coupling in the FeAs layers. Short range order in both the Fe
and Pr moments persists for higher levels of x. The static magnetic moments
disappear at a concentration coincident with that expected for percolation of
the J1-J2 square lattice model
Modeling eating disorders of cognitive impaired people
Millions of people all around the world suffer from eating
disorders, known as anorexia nervosa, bulimia nervosa, pica, and others. When eating disorders coexist with other mental health disorders, eating disorders often go undiagnosed and untreated; a low number of sufferers
obtain treatment for the eating disorder. Unfortunately, eating disorders have also the highest mortality rate of any mental illness, upwards of 20%.
This paper focuses on monitoring eating disorders of cognitive impaired people as patients with the Alzheimer’s disease. The proposed approach relies on the application of Ambient Intelligence (AmI) technologies and a new method for the detection of abnormal human behaviors in a controlled environment
Clustering of vertically constrained passive particles in homogeneous, isotropic turbulence
We analyze the dynamics of small particles vertically confined, by means of a
linear restoring force, to move within a horizontal fluid slab in a
three-dimensional (3D) homogeneous isotropic turbulent velocity field. The
model that we introduce and study is possibly the simplest description for the
dynamics of small aquatic organisms that, due to swimming, active regulation of
their buoyancy, or any other mechanism, maintain themselves in a shallow
horizontal layer below the free surface of oceans or lakes. By varying the
strength of the restoring force, we are able to control the thickness of the
fluid slab in which the particles can move. This allows us to analyze the
statistical features of the system over a wide range of conditions going from a
fully 3D incompressible flow (corresponding to the case of no confinement) to
the extremely confined case corresponding to a two-dimensional slice. The
background 3D turbulent velocity field is evolved by means of fully resolved
direct numerical simulations. Whenever some level of vertical confinement is
present, the particle trajectories deviate from that of fluid tracers and the
particles experience an effectively compressible velocity field. Here, we have
quantified the compressibility, the preferential concentration of the
particles, and the correlation dimension by changing the strength of the
restoring force. The main result is that there exists a particular value of the
force constant, corresponding to a mean slab depth approximately equal to a few
times the Kolmogorov length scale, that maximizes the clustering of the
particles
The heuristic strategies for assessing wireless sensor network: an event-based formal approach
Wireless Sensor Networks (WSNs) are increasingly being adopted in critical applications. In these networks undesired events may undermine the reliability level; thus their effects need to be properly assessed from the early stages of the development process onwards to minimize the chances of unexpected problems during use. In this paper we propose two heuristic strategies: what-if analysis and robustness checking. They allow to drive designers towards optimal WSN deployment solutions, from the point of view of the connection and data delivery resiliency, exploiting a formal approach based on the event calculus formal language. The heuristics are backed up by a support tool aimed to simplify their adoption by system designers. The tool allows to specify the target WSN in a user-friendly way and it is able to elaborate the two heuristic strategies by means of the event calculus specifications automatically generated. The WSN reliability is assessed computing a set of specific metrics. The effectiveness of the strategies is shown in the context of three case studies
Signals of Warped Extra Dimensions at the LHC
We discuss the signatures of the spin-2 graviton excitations predicted by the
Randall-Sundrum model with one warped extra dimension, in dilepton and diphoton
production at LHC. By using a specific angular analysis, we assess the ranges
in mass and coupling constant where such gravitons can be discriminated against
competitor spin-1 and spin-0 objects, that potentially could manifest
themselves in these processes with the same mass and rate of events. Depending
on the value of the coupling constant to quarks and leptons, the numerical
results indicate graviton identification mass ranges up to 1.1-2.4 TeV and
1.6-3.2 TeV for LHC nominal energy of 14 TeV and time-integrated luminosity of
10 and 100~, respectively.Comment: 8 pages, Talk given at QCD@Work - International Workshop on QCD -
Theory and Experiment, 20 - 23 June, 2010, Martina Franca Ital
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Destination Online Communication: Why Less is Sometimes More. A Study of Online Communications of English Destinations
This research investigates the relationship between Web site design and the Web site end-user experience of a vast number of English tourism destinations, both local and regional ones. Following recent research in the field, this paper evaluates destinations' online communication based on the implemented Web site features and on the effectiveness of the communication itself, borrowing its research methodology from different domains. After content and functionality analysis, a user-experience, scenario-based investigation has been carried out, which demonstrated that complex Web sites do not always serve end-users' needs properly; in other words, Web site complexity is not directly related with good user experience. This research may help destination managers to foster their online communication if they have fewer content and functionalities but are better focused and clearly user-oriented. © 2014 Taylor & Francis
A geobotanical survey on acidophilous grasslands in the Abruzzo, Lazio and Molise National Park (Central Italy)
The acidophilous grasslands of the south-eastern part of the Abruzzo, Lazio and Molise National Park was studied by the phytosociological method and analyzed from a synecological viewpoint with the help of soil analysis. Four clusters of relevés resulted from the numerical classification. Syntaxonomically they were ascribed to the following associations: Poo violaceae-Nardetum strictae, Potentillo rigoanae-Festucetum paniculatae, Nardo strictae-Brachypodietum genuensis and Potentillo rigoanae-Brachypodietum genuensis. Since the original proposal of all the syntaxa identified in the present study were affected by nomenclatural mistakes, they were corrected in accordance with the rules of ICPN. The occurrence of Anthoxanto-Brachypodietum in central Apennines, is excluded since this association falls in syntaxonomical synonymy with Potentillo-Brachypodietum. The synecological analysis proved that the distribution of the different communities identified within the study area to be correlated with topographic, geomorphological and soil factors. Among these latter, the ratio H+/basic cations, pH behave as the most influencing parameters in the distribution of the communities identified
Locking-free curved elements with refined kinematics for the analysis of composite structures
A new class of refined curved beam elements is proposed for the accurate stress analysis of composite structures. The element
possesses three-dimensional capabilities and it is suited for the study of curved laminates and fiber-reinforced composites at
the microscopic scale. The numerical issues associated with membrane and shear lockings are overcome by means of assumed
interpolations of the strain components based on the mixed interpolation of tensorial components method (MITC). Higher-order
expansions with only displacement unknowns are employed for the cross-section assumptions at the component level, enabling
the computation of component-wise stress fields. For this purpose, a hierarchical set of Legendre functions is implemented, which
allows the user to tune the kinematics of the element through the polynomial order input. The detrimental effects of locking in
composite modeling are investigated and the robustness and efficiency of the beam element is assessed through comparison against
solutions from the literature and refined solid models
Partial purification and MALDI-TOF MS analysis of UN1, a tumor antigen membrane glycoprotein.
UN1 is a membrane glycoprotein that is expressed in immature human thymocytes, a subpopulation of peripheral T lymphocytes, the HPB acute lymphoblastic leukemia (ALL) T-cell line and fetal thymus. We previously reported the isolation of a monoclonal antibody (UN1 mAb) recognizing the UN1 protein that was classified as "unclustered" at the 5th and 6th International Workshop and Conference on Human Leukocyte Differentiation Antigens. UN1 was highly expressed in breast cancer tissues and was undetected in non-proliferative lesions and in normal breast tissues, indicating a role for UN1 in the development of a tumorigenic phenotype of breast cancer cells. In this study, we report a partial purification of the UN1 protein from HPB-ALL T cells by anion-exchange chromatography followed by immunoprecipitation with the UN1 mAb and MALDI-TOF MS analysis. This analysis should assist in identifying the amino acid sequence of UN
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