31,102 research outputs found
Foraging Behavior of Tetramorium Caespitum in an Urban Environment: the Effect of Food Quality on Foraging
Animals\u27 foraging strategies are directly related to their fitness. Proposed models of optimal foraging assume that animals strategize in terms of maximizing benefits over the cost of acquiring resources. Ants are social insects that are comparable in biomass to humans inhabiting the plant. As such, it is crucial to understand the foraging strategies of such an influential member of the ecosystem. With the ever-increasing rate of urbanization and human encroachment, it is even more important to consider the foraging patterns of species inhabiting urban areas. In this study we investigate optimal foraging strategies in the pavement ant, Tetramorium caespitum. Specifically, our study examined if pavement ant colonies would alter their foraging behavior so as to maximize benefits and minimize costs. To do this, we exposed the ants to food of two varying nutritional qualities to test how they allocated foragers across these two resources.Food quantity, distance to the food source and terrain were the same in both types of resources. Across a two day period, we saw that T. caespitum colonies increased ant recruitment when food quality increased and decreased ant recruitment when food quality decreased. Our control treatments where food quality did not change also did not see a change in ant recruitment. This study shows that species that live in urban areas, such as T. caespitum, can adapt to forage optimally. Studies like this can be used to make predictions about survival of species that are newly associated with urban environments
Higgs Physics at the Large Hadron Collider
In this talk I will begin by summarising the importance of the Higgs physics
studies at the LHC. I will then give a short description of the pre-LHC
constraints on the Higgs mass and the theoretical predictions for the LHC along
with a discussion of the current experimental results, ending with prospects in
the near future at the LHC. In addition to the material covered in the
presented talk, I have included in the writeup, a critical appraisal of the
theoretical uncertainties in the Higgs cross-sections at the Tevatron as well
as a discussion of the recent experimental results from the LHC which have
become available since the time of the workshop.Comment: LateX, 12 figures, 15 pages, Presented at the XIth Workshop on High
Energy Physics Phenomenology, 2010, Ahmedabad, Indi
Yukawa potentials in systems with partial periodic boundary conditions II : Lekner sums for quasi-two dimensional systems
Yukawa potentials may be long ranged when the Debye screening length is
large. In computer simulations, such long ranged potentials have to be taken
into account with convenient algorithms to avoid systematic bias in the
sampling of the phase space. Recently, we have provided Ewald sums for
quasi-two dimensional systems with Yukawa interaction potentials [M. Mazars,
{\it J. Chem. Phys.}, {\bf 126}, 056101 (2007) and M. Mazars, {\it Mol. Phys.},
Paper I]. Sometimes, Lekner sums are used as an alternative to Ewald sums for
Coulomb systems. In the present work, we derive the Lekner sums for quasi-two
dimensional systems with Yukawa interaction potentials and we give some
numerical tests for pratical implementations. The main result of this paper is
to outline that Lekner sums cannot be considered as an alternative to Ewald
sums for Yukawa potentials. As a conclusion to this work : Lekner sums should
not be used for quasi-two dimensional systems with Yukawa interaction
potentials.Comment: 25 pages, 5 figures and 1 tabl
Telaah Pemikiran Ekonomi Menurut Ibnu Qayyim (1292-1350 M / 691-751 H)
Dewasa ini, Barat seringkali menjadi poros atau kiblat pemikiran ekonomi dunia. Hampir bisa dipastikan bahwa ilmu-ilmu ekonomi yang diajarkan bangku-bangku sekolah dan perguruan tinggi adalah pemikiran ekonomi yang bermazhab pada kapitalis Barat. Padahal jauh sebelum pemikiran ekonomi dari Barat, Islam telah memiliki suatu konsep ekonomi yang di sampaikan oleh para pemikir-pemikir muslim yang merangkap pula sebagai ulama. Tulisan ini mencoba menguraikan pemikiran ekonomi menurut sudut pandang salah satu ulama yang hidup pada abad puncak kejayaan peradaban Islam, Ulama tersebut yaitu Ibnu Qayyim. Penulis mencoba menjelaskan apa dan bagaimana pemikiran ekonomi menurut Ibnu Qayyim al-Jawziyyah. Metode yang digunakan dalam penyempurnaan tulisan ini adalah, studi leteratur yang di ambil dari berbagai sumber baik itu beberapa buku karya Ibnu Qayyim sendiri, maupun buku dan jurnal-jurnal terkait yang di dalamnya memuat cara pandang Ibnu Qayyim berkaitan dengan ekonomi
Compressible primitive equation: formal derivation and stability of weak solutions
We present a formal derivation of a simplified version of Compressible
Primitive Equations (CPEs) for atmosphere modeling. They are obtained from
-D compressible Navier-Stokes equations with an \emph{anisotropic viscous
stress tensor} where viscosity depends on the density. We then study the
stability of the weak solutions of this model by using an intermediate model,
called model problem, which is more simple and practical, to achieve the main
result
An improvement in support vector machine classification model using grey relational analysis for cancer diagnosis
To further improve the accuracy of classifier for cancer diagnosis, a hybrid model called GRA-SVM which comprises Support Vector Machine classifier and filter feature selection Grey Relational Analysis is proposed and tested against Wisconsin Breast Cancer Dataset (WBCD) and BUPA Disorder Dataset. The performance of GRA-SVM is compared to SVM’s in terms of accuracy, sensitivity, specificity and Area under Curve (AUC). The experimental results reveal that GRA-SVM improves the SVM accuracy of about 0.48 by using only two features for the WBCD dataset. For BUPA dataset, GRA-SVM improves the SVM accuracy of about 0.97 by using four features. Besides improving the accuracy performance, GRA-SVM also produces a ranking scheme that provides information about the priority of each feature. Therefore, based on the benefits gained, GRA-SVM is recommended as a new approach to obtain a better and more accurate result for cancer diagnosis
Higgs Physics: Theory
I review the theoretical aspects of the physics of Higgs bosons, focusing on
the elements that are relevant for the production and detection at present
hadron colliders. After briefly summarizing the basics of electroweak symmetry
breaking in the Standard Model, I discuss Higgs production at the LHC and at
the Tevatron, with some focus on the main production mechanism, the gluon-gluon
fusion process, and summarize the main Higgs decay modes and the experimental
detection channels. I then briefly survey the case of the minimal
supersymmetric extension of the Standard Model. In a last section, I review the
prospects for determining the fundamental properties of the Higgs particles
once they have been experimentally observed.Comment: 21 pages, 15 figures. Talk given at the XXV International Symposium
on Lepton Photon Interactions at High Energies (Lepton Photon 11), 22-27
August 2011, Mumbai, Indi
Higgs production in CP-violating supersymmetric cascade decays: probing the `open hole' at the Large Hadron Collider
A benchmark CP-violating supersymmetric scenario (known as 'CPX-scenario' in
the literature) is studied in the context of the Large Hadron Collider (LHC).
It is shown that the LHC, with low to moderate accumulated luminosity, will be
able to probe the existing `hole' in the - plane, which
cannot be ruled out by the LEP data. We explore the parameter space with
cascade decay of third generation squarks and gluino with CP-violating decay
branching fractions. We propose a multi-channel analysis to probe this
parameter space some of which are background free at an integrated luminosity
of 5-10 fb. Specially, multi-lepton final states (3\l,\, 4\l and like
sign di-lepton) are almost background free and have reach for the
corresponding signals with very early data of LHC for both 14 TeV and 7 TeV
center of mass energy.Comment: 24 pages, 9 figures, references added as in the journal versio
The Monte Carlo Event Generator DPMJET-III
A new version of the Monte Carlo event generator DPMJET is presented. It is a
code system based on the Dual Parton Model and unifies all features of the
DTUNUC-2, DPMJET-II and PHOJET 1.12 event generators. DPMJET-III allows the
simulation of hadron-hadron, hadron-nucleus, nucleus-nucleus, photon-hadron,
photon-photon and photon-nucleus interactions from a few GeV up to the highest
cosmic ray energies.Comment: 6 pages, Talk given at the Conference ``Monte Carlo 2000'', Lisbon,
Portugal, 23-26 Oct. 200
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