2,255 research outputs found
Comparison of DC and SRF Photoemission Guns For High Brightness High Average Current Beam Production
A comparison of the two most prominent electron sources of high average
current high brightness electron beams, DC and superconducting RF photoemission
guns, is carried out using a large-scale multivariate genetic optimizer
interfaced with space charge simulation codes. The gun geometry for each case
is varied concurrently with laser pulse shape and parameters of the downstream
beamline elements of the photoinjector to obtain minimum emittance as a
function of bunch charge. Realistic constraints are imposed on maximum field
values for the two gun types. The SRF and DC gun emittances and beam envelopes
are compared for various values of photocathode thermal emittance. The
performance of the two systems is found to be largely comparable provided low
intrinsic emittance photocathodes can be employed
SU(N) Coherent States
We generalize Schwinger boson representation of SU(2) algebra to SU(N) and
define coherent states of SU(N) using bosonic harmonic
oscillator creation and annihilation operators. We give an explicit
construction of all (N-1) Casimirs of SU(N) in terms of these creation and
annihilation operators. The SU(N) coherent states belonging to any irreducible
representations of SU(N) are labelled by the eigenvalues of the Casimir
operators and are characterized by (N-1) complex orthonormal vectors describing
the SU(N) manifold. The coherent states provide a resolution of identity,
satisfy the continuity property, and possess a variety of group theoretic
properties.Comment: 25 pages, LaTex, no figure
Genetic variability, stability and heritability for quality and yield characteristics in provitamin A cassava varieties
Open Access Article; Published online: 25 Jan 2020Cassava is widely consumed in many areas of Africa, including Ghana, and is a major part of most household diets. These areas are characterized by rampant malnutrition, because the tuberous roots are low in nutritional value. Provitamin A biofortified cassava varieties have been developed by the International Institute for Tropical Agriculture, but adoption of these varieties in Ghana will largely depend on their agronomic performance, including fresh root yield, dry matter content, resistance to major pests and diseases, mealiness, starch content and the stability of these traits. Eight provitamin A varieties with two white checks were planted in three environments for two seasons to determine stability and variability among the varieties for important traits. There were significant variations in performance between varieties and between environments for cassava mosaic disease, root number, fresh root yield and starch content. High broad-sense heritability and genetic advance were observed in all traits, except for storage root number, and could be exploited through improvement programs. This study identified the best performing enhanced provitamin A varieties for traits that are key drivers of variety adoption in Ghana. In view of this, some varieties can be recommended for varietal release after on-farm testing. The study also showed the possibility of tapping heterosis after careful selection of parents
A Medical Analysis for Colorectal Lymphomas using 3D MRI Images and Deep Residual Boltzmann CNN Mechanism
In this technological world the healthcare is very crucial and difficult to spend time for the wellbeing. The lifestyle disease can transform in to the life threating disease and lead to critical stages. Colorectal lymphomas are the 3rd most malignancy death in the entire world. The estimation of the volume of lymphomas is often used by Magnetic Resonance Imaging during medical diagnosis, particularly in advanced stages. The research study can be classified in multiple stages. In the initial stages, an automated method is used to calculated the volume of the colorectal lymphomas using 3D MRI images. The process begins with feature extraction using Iterative Multilinear Component Analysis and Multiscale Phase level set segmentation based on CNN model. Then, a logical frustum model is utilized for 3D simulation of colon lymphoma for rendering the medical data. The next stages is focused on tackling the matter of segmentation and classification of abnormality and normality of lymph nodes. A semi supervised fuzzy logic algorithm for clustering is used for segmentation, whereas bee herd optimization algorithm with scale down for employed to intensify corresponding classifier rate of detection. Finally, classification is performed using Deep residual Boltzmann CNN. Our proposed methodology gives a better results and diagnosis prediction for lymphomas for an accuracy 97.7%, sensitivity 95.7% and specify as 95.8% which is superior than the traditional approach
Coherent States For SU(3)
We define coherent states for SU(3) using six bosonic creation and
annihilation operators. These coherent states are explicitly characterized by
six complex numbers with constraints. For the completely symmetric
representations (n,0) and (0,m), only three of the bosonic operators are
required. For mixed representations (n,m), all six operators are required. The
coherent states provide a resolution of identity, satisfy the continuity
property, and possess a variety of group theoretic properties. We introduce an
explicit parameterization of the group SU(3) and the corresponding integration
measure. Finally, we discuss the path integral formalism for a problem in which
the Hamiltonian is a function of SU(3) operators at each site.Comment: 18 pages, LaTeX, no figure
Breast Tumor Simulation and Parameters Estimation Using Evolutionary Algorithms
An estimation methodology is presented to determine the breast tumor parameters using the surface temperature profile that may be obtained by infrared thermography. The estimation methodology involves evolutionary algorithms using artificial neural network (ANN) and genetic algorithm (GA). The ANN is used to map the relationship of tumor parameters (depth, size, and heat generation) to the temperature profile over the idealized breast model. The relationship obtained from ANN is compared to that obtained by finite element software. Results from ANN training/testing were in good agreement with those obtained from finite element model. After ANN validation, GA is used to estimate tumor parameters by minimizing a fitness function involving comparing the temperature profiles from simulated or clinical data to those obtained by ANN. Results show that it is possible to determine the depth, diameter, and heat generation rate from the surface temperature data (with 5% random noise) with good accuracy for the 2D model. With 10% noise, the accuracy of estimation deteriorates for deep-seated tumors with low heat generation. In order to further develop this methodology for use in a clinical scenario, several aspects such as 3D breast geometry and the effects of nonuniform cooling should be considered in future investigations
Awareness about diabetes mellitus and DKA among medical students: an observational study
Background: Diabetes Mellitus (DM) is a global epidemic and a leading cause for increased mortality and morbidity. The prevalence of Diabetes is very high so the management of DM and its complication like diabetic ketoacidosis (DKA) is very crucial in today’s world. Medical students being the future pillars of our health care system were included in this study to know their knowledge towards diabetes and its acute complication DKA.Methods: This study was a questionnaire based observational study conducted in Adichunchanagiri Institute of Medical Sciences, B G Nagara. Final year medical students and interns were included in the study.Results: A total of 150 (75 from each group) questionnaires were collected and analysed. Most of the final year students and interns were aware about the classical symptoms of diabetes (73.33% and 84% respectively) and were aware about the endocrine gland related to diabetes (82.6% and 94.6% respectively) however there were differences about the meaning of PPBS among both the groups. Interns (76%) had better knowledge regarding the fluid replacement in the management of DKA in compared to final year students (41.33%). There was statistically significant difference in knowledge between the two groups regarding GDM.Conclusions: This study identifies that both final year students and interns need to improve the practical knowledge towards diagnostic parameters of DM and treatment of DKA. Continous medical education programmes and workshops should be organised to enhance the knowledge towards DM and its complications
Walking dynamics are symmetric (enough)
Many biological phenomena such as locomotion, circadian cycles, and breathing
are rhythmic in nature and can be modeled as rhythmic dynamical systems.
Dynamical systems modeling often involves neglecting certain characteristics of
a physical system as a modeling convenience. For example, human locomotion is
frequently treated as symmetric about the sagittal plane. In this work, we test
this assumption by examining human walking dynamics around the steady-state
(limit-cycle). Here we adapt statistical cross validation in order to examine
whether there are statistically significant asymmetries, and even if so, test
the consequences of assuming bilateral symmetry anyway. Indeed, we identify
significant asymmetries in the dynamics of human walking, but nevertheless show
that ignoring these asymmetries results in a more consistent and predictive
model. In general, neglecting evident characteristics of a system can be more
than a modeling convenience---it can produce a better model.Comment: Draft submitted to Journal of the Royal Society Interfac
Interfacial propulsion by directional adhesion
The rough integument of water-walking arthropods is well-known to be responsible for their water-repellency [1], [2], [3] and [4]; however, water-repellent surfaces generally experience reduced traction at an air–water interface [5], [6], [7] and [8]. A conundrum then arises as to how such creatures generate significant propulsive forces while retaining their water-repellency. We here demonstrate through a series of experiments that they do so by virtue of the detailed form of their integument; specifically, their tilted, flexible hairs interact with the free surface to generate directionally anisotropic adhesive forces that facilitate locomotion. We thus provide new rationale for the fundamental topological difference in the roughness on plants and water-walking arthropods, and suggest new directions for the design and fabrication of unidirectional superhydrophobic surfaces
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