2,768 research outputs found
Structure, electronic properties and magnetic transition in manganese clusters
We systematically investigate the structural, electronic and magnetic
properties of Mn clusters ( 220) within the {\it ab-initio}
pseudopotential plane wave method using generalized gradient approximation for
the exchange-correlation energy. A new kind of icosahedral structural growth
has been predicted in the intermediate size range. Calculated magnetic moments
show an excellent agreement with the Stern-Gerlach experiment. A transition
from ferromagnetic to ferrimagnetic MnMn coupling takes place at 5 and
the ferrimagnetic states continue to be the ground states for the entire size
range. Possible presence of multiple isomers in the experimental beam has been
argued. No signature of non-metal to metal transition is observed in this size
range and the coordination dependence of electron localization is
discussed.Comment: 11 Pages and 9 Figures. Physical Review B (in press
Large Magnetic Moments of Arsenic-Doped Mn Clusters and their Relevance to Mn-Doped III-V Semiconductor Ferromagnetism
We report electronic and magnetic structure of arsenic-doped manganese
clusters from density-functional theory using generalized gradient
approximation for the exchange-correlation energy. We find that arsenic
stabilizes manganese clusters, though the ferromagnetic coupling between Mn
atoms are found only in MnAs and MnAs clusters with magnetic moments 9
and 17 , respectively. For all other sizes, 3, 5-10,
MnAs clusters show ferrimagnetic coupling. It is suggested that, if grown
during the low temperature MBE, the giant magnetic moments due to ferromagnetic
coupling in MnAs and MnAs clusters could play a role on the
ferromagnetism and on the variation observed in the Curie temperature of
Mn-doped III-V semiconductors.Comment: 4 Pages, 3 Figures[1 EPS and 2 JPG files], RevTeX
LABORATORY EVALUATION OF EFFICACY OF THREE DIATOMACEOUS EARTH FORMULATIONS AGAINST TRIBOLIUM CASTANEUM HERBST (COLEOPTERA: TENEBRIONIDAE) IN STORED WHEAT
Laboratory experiments were conducted to evaluate three DE formulations - Protect-It, DiaFil 610 and Celite 209 at dose rates 500, 750 and 1000 mg/kg of wheat, against the red flour beetle Tribolium castaneum Herbst under ambient laboratory conditions (26 - 32°C and 48 - 65% r.h.). Mortality of exposed adults increased with increase in dose and exposure period; however consistency was notable only after 7days of exposure. With all DE formulations, mortality was low on grains treated at 500 and 750 mg/kg after 3 and 7 days of exposure. Protect-It was highly effectives at 1000 mg/kg causing 100% adult mortality after 3 days of exposure. Similarly, all the three DE formulations caused complete adult mortality on grains treated at 750 and 1000 mg/kg after 14 days of exposure. In addition, at these dose rates complete progeny suppression was recorded except on grain treated with DiaFil 610 at 750 mg/kg. The findings of this study have demonstrated that the efficacy of the three DE formulations to control T. castaneum and as potential alternative to synthetic insecticides
Een nadere analyse van de relatie tussen aandelenrendementen en winsten, dividenden en cash-flows
Profit;Cash Flow;Return on Investment;Dividends;finance
Concept and challenges of delivering preventive and care services in prehospital emergency medical service: A qualitative study
Background and purpose: Prehospital emergency medical service (EMS) is an important part of the health care system. Today, the need for integrated emergency care services and delivering qualified preventive and care services felt more than before in accidents and emergencies. This survey aimed to investigate the views of emergency medical personnel on the concept and nature of preventive and care services and current challenges in delivering these services in prehospital EMS centers in Golestan province, Iran. Materials and methods: A qualitative study was done with 16 emergency medical personnel working in EMS sites in Golestan province using purposeful sampling. Data was collected by semistructured interview guide and framework analysis was implemented to analyze the data. Results: Two general themes were identified including 1) the concept of preventive and care services in the EMS and 2) the challenges in providing qualified services in the EMS sites in Golestan province. Also, five sub-themes and 12 subclasses were determined. Conclusion: To enhance and promote services, the EMS system of Golestan province need reforms in organizational structure, laws and administrative regulations, training programs, the system of monitoring and evaluation of personnel, also provision of equipment and manpower and provision of personnel amenities to improve the staff performance. Furthermore, it is necessary to boost emergency services at the community level through training people and enhancing collaboration and participation with other organizations. © 2015, Mazandaran University of Medical Sciences. All rights reserved
Active and Passive Quantum Erasers for Neutral Kaons
Quantum marking and quantum erasure are discussed for the neutral kaon
system. Contrary to other two-level systems, strangeness and lifetime of a
neutral kaon state can be alternatively measured via an "active" or a "passive"
procedure. This offers new quantum erasure possibilities. In particular, the
operation of a quantum eraser in the "delayed choice" mode is clearly
illustrated.Comment: 17 pages, LaTeX, 1 figure, references added, accepted by Phys. Rev.
Quantum marking and quantum erasure for neutral kaons
Entangled K0 anti-K0 pairs are shown to be suitable to discuss extensions and
tests of Bohr's complementarity principle through the quantum marking and
quantum erasure techniques suggested by M. O. Scully and K. Druehl [Phys. Rev.
A 25, 2208 (1982)]. Strangeness oscillations play the role of the traditional
interference pattern linked to wave-like behaviour, whereas the distinct
propagation in free space of the K_S and K_L components mimics the two possible
interferometric paths taken by particle-like objects.Comment: 4 RevTeX page
Emergence of noncollinear magnetic ordering in small magnetic clusters: Mn and As@Mn
Using first-principles density functional calculations, we have studied the
magnetic ordering in pure Mn (10, 13, 15, 19) and As@Mn
(10) clusters. Although, for both pure and doped manganese clusters,
there exists many collinear and noncollinear isomers close in energy, the
smaller clusters with 5 have collinear magnetic ground state and
the emergence of noncollinear ground states is seen for 6 clusters.
Due to strong hybridization in As@Mn clusters, the binding energy is
substantially enhanced and the magnetic moment is reduced compared to the
corresponding pure Mn clusters.Comment: 10 Pages and 5 Figure
RISA: Round-Robin Intra-Rack Friendly Scheduling Algorithm for Disaggregated Datacenters
Recent trends see a move away from a fixed-resource server-centric datacenter
model to a more adaptable "disaggregated" datacenter model. These disaggregated
datacenters can then dynamically group resources to the specific requirements
of an incoming workload, thereby improving efficiency. To properly utilize
these disaggregated datacenters, workload allocation techniques must examine
the current state of the datacenter and choose resources that not only optimize
the current workload request, but future ones. Since disaggregated datacenters
are severely bottlenecked by the available network resources, our work proposes
a heuristic-based approach called RISA, which significantly reduces the network
usage of workload allocations in disaggregated datacenters. Compared to the
state-of-the-art, RISA reduces the power consumption for optical components by
33% and reduces the average CPU-RAM round-trip latency by 50%. Additionally,
RISA significantly outperforms the state-of-the-art in terms of execution time.Comment: Clarified some prior work and their citation
A novel statistical technique for intrusion detection systems
This paper proposes a novel approach for intrusion detection system based on sampling with Least Square Support Vector Machine (LS-SVM). Decision making is performed in two stages. In the first stage, the whole dataset is divided into some predetermined arbitrary subgroups. The proposed algorithm selects representative samples from these subgroups such that the samples reflect the entire dataset. An optimum allocation scheme is developed based on the variability of the observations within the subgroups. In the second stage, least square support vector machine (LS-SVM) is applied to the extracted samples to detect intrusions. We call the proposed algorithm as optimum allocation-based least square support vector machine (OA-LS-SVM) for IDS. To demonstrate the effectiveness of the proposed method, the experiments are carried out on KDD 99 database which is considered a de facto benchmark for evaluating the performance of intrusions detection algorithm. All binary-classes and multiclass are tested and our proposed approach obtains a realistic performance in terms of accuracy and efficiency. Finally a way out is also shown the usability of the proposed algorithm for incremental datasets
- …