Hasil untuk "physics.atm-clus"

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arXiv Open Access 2025
Optical cycling of MgF molecules within the hyperfine states in X(N=1) state

Kikyeong Kwon, Seunghwan Roh, Youngju Cho et al.

We investigated the optical cycling effect of the $\mathrm{X}^2Σ(v=0,\ N=1^-) - \mathrm{A}^2Π_{1/2}(v'=0,\ J'=1/2^+)$ band of MgF molecules, specifically the $\mathrm{P_1/Q_{12}(1)}$ transition, which serves as the main transition in the quasi-closed cycling scheme for the laser cooling. A higher number of scattered photons was observed when all three frequency components of the $\mathrm{P_1/Q_{12}(1)}$ transition were simultaneously applied using acousto-optic modulators (AOMs). Optimal conditions were identified by scanning the detuning of frequency components, the laser beam power ratio, and the total laser beam power, and the results were confirmed through rate equation simulations. Under these optimized conditions, and with an applied magnetic field, the scattering rate was enhanced by approximately a factor of six. These results refine the implementation of optical cycling in MgF and lay the groundwork for laser slowing and magneto-optical trapping (MOT) experiments.

en physics.atm-clus, physics.atom-ph
arXiv Open Access 2025
Electron scattering from aminoacetonitrile: effects of polarisation-correlation and basis-set on cross section

Irabati Chakraborty, Bobby Antony

Aminoacetonitrile occupies a prime importance in the interface between astrochemistry and prebiotic chemistry. Its detection in the ISM establishes it as part of the organic inventory of star-forming regions, while its role as a glycine precursor highlights its significance for origins-of-life scenarios. In this work, electron scattering from aminoacetonitrile has been studied using the $R$-matrix method in the low-energy range from $\sim$0 to 10 eV. The calculations were carried out within the $C_{s}$ point group using static-exchange (SE), static-exchange plus polarisation (SEP), and configuration interaction (CI) models, with two basis sets (6-311G* and cc-pVTZ) to understand their dependence on cross section. Various scattering observables, such as differential elastic cross section, integral elastic, excitation, and momentum transfer cross sections, were examined. Since aminoacetonitrile is a prebiotically relevant molecule, these findings provide valuable insight into electron-driven processes in complex organic systems and form a theoretical foundation for future work on electron-induced reactivity in prebiotic and astrophysical environments.

en physics.atm-clus, physics.app-ph
CrossRef Open Access 2024
The Role of Information Management in Enhancing Organizational Resilience

April Lansonia, Matthias Austin

In the face of constant change and unprecedented challenges, organizations are compelled to cultivate resilience. This study focuses on the pivotal role of information management in fortifying organizational resilience, recognizing the imperative for a strategic approach to information handling in today's dynamic landscape. Employing a quantitative research approach, the study aims to comprehensively understand the nuanced relationships between information management and organizational resilience. By capturing empirical data, quantitative methodologies enable statistical analysis to unveil patterns and trends, shedding light on the presence, strength, and direction of the relationship between information management practices and resilience. The study's contributions extend to both academic and practical realms. Academic researchers gain insights into how strategic information management influences organizational resilience, informing the development of new theories. Practitioners can leverage actionable insights to guide strategic decision-making, enhancing organizational adaptation and thriving. Whether through improving data security, enhancing information accessibility, or refining data management, organizations can fortify their foundations in the ever-evolving business landscape. In conclusion, this study offers practical implications for organizational leaders, emphasizing the pivotal role of strategic information management in not only surviving but thriving amid disruptions. The synthesis of empirical evidence and theoretical insights positions this research as a valuable resource for those dedicated to bolstering organizational resilience in the face of dynamic uncertainties.

4 sitasi en
arXiv Open Access 2024
High- and low-energy many-body effects of graphene in a unified approach

Alberto Guandalini, Giovanni Caldarelli, Francesco Macheda et al.

We show that the many-body features of graphene band structure and electronic response can be accurately evaluated by applying many-body perturbation theory to a tight-binding (TB) model. In particular, we compare TB results for the optical conductivity with previous ab-initio calculations, showing a nearly perfect agreement both in the low energy region near the Dirac cone ($\sim 100$ meV), and at the higher energies of the π plasmon ($\sim 5$ eV). A reasonable agreement is reached also for the density-density response at the Brillouin zone corner. With the help of the reduced computational cost of the TB model, we study the effect of self-consistency on the screened interaction (W) and on the quasi-particle corrections, a task that is not yet achievable in ab-initio frameworks. We find that self-consistency is important to reproduce the experimental results on the divergence of the Fermi velocity, while it marginally affects the optical conductivity. Finally, we study the robustness of our results against doping or the introduction of a uniform dielectric environment.

en physics.atm-clus
arXiv Open Access 2022
ESPNN: A novel electronic stopping power neural-network code built on the IAEA stopping power database. I. Atomic targets

F. Bivort Haiek, A. M. P. Mendez, C. C. Montanari et al.

The International Atomic Energy Agency (IAEA) stopping power database is a highly valued public resource compiling most of the experimental measurements published over nearly a century. The database-accessible to the global scientific community-is continuously updated and has been extensively employed in theoretical and experimental research for more than 30 years. This work aims to employ machine learning algorithms on the 2021 IAEA database to predict accurate electronic stopping power cross sections for any ion and target combination in a wide range of incident energies. Unsupervised machine learning methods are applied to clean the database in an automated manner. These techniques purge the data by removing suspicious outliers and old isolated values. A large portion of the remaining data is used to train a deep neural network, while the rest is set aside, constituting the test set. The present work considers collisional systems only with atomic targets. The first version of the ESPNN (electronic stopping power neural-network code), openly available to users, is shown to yield predicted values in excellent agreement with the experimental results of the test set.

en physics.atm-clus, cs.LG
S2 Open Access 2021
Efficient Time Synchronization Technology of Wireless Network

Tao Chen, Qilong Du, Yunqi Tian et al.

Time synchronization technology is an important topic in wireless self-organizing networks. It mainly affects the operational efficiency of the network from the aspects of delay, synchronization accuracy, network collision rate. We improve the synchronization delay and flood broadcast time synchronization algorithm respectively so that the time synchronization technology can adapt to wireless ad hoc networks. Firstly, the paper improves the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) backoff algorithm, Secondly, we carry out maximum likelihood compensation for Flooding Time Synchronization Protocol (FTSP) processing delay to reduce synchronization error. Finally, we use clustered FSTP (Clu-FSTP)to reduces the number of flooding nodes and improves the synchronization efficiency. Compared with CSMA / CA and OrderGain algorithm, it greatly reduces the access delay. In a network with 36 nodes, the maximum synchronization error is reduced by about $1.5\ \mu s$ on average. The number of nodes involved in the broadcast synchronization grouping of the algorithm is lower than that of FTSP around 50%. The improvement of time synchronization technology has very important value for the research progress of communication networks.

3 sitasi en Computer Science
arXiv Open Access 2019
Spectroscopy of corannulene cations in helium nanodroplets

Michael Gatchell, Paul Martini, Felix Laimer et al.

Helium tagging in action spectroscopy is an efficient method for measuring the absorption spectrum of complex molecular ions with minimal perturbations to the gas phase spectrum. We have used superfluid helium nanodroplets doped with corannulene to prepare cations of these molecules complexed with different numbers of He atoms. In total we identify 13 different absorption bands from corannulene cations between 5500 Å and 6000 Å. The He atoms cause a small, chemically induced redshift to the band positions of the corannulene ion. By studying this effect as a function of the number of solvating atoms we are able to identify the formation of solvation structures that are not visible in the mass spectrum. The solvation features detected with the action spectroscopy agree very well with the results of atomistic modeling based on path-integral molecular dynamics simulations. By additionally doping our He droplets with D$_2$, we produce protonated corannulene ions. The absorption spectrum of these ions differs significantly from the case of the radical cations as the numerous narrow bands are replaced by a broad absorption feature that spans nearly 2000 Å in width.

en physics.atm-clus, astro-ph.GA
S2 Open Access 2018
Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls.

F. Cruz-Sanabria, K. Bonilla-Vargas, K. Estrada et al.

INTRODUCTION Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease. OBJECTIVE To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ɛ2, ɛ3, ɛ4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU (rs227959 and rs11136000) in patients with MCI and healthy individuals. METHODOLOGY We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics. RESULTS We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend toward poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance. DISCUSSION Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples.

11 sitasi en Biology, Medicine
CrossRef Open Access 2017
Implementation System of Business Intelligence System In The Company

Abdul Hamid Arribathi, Maimunah Maimunah, Devi Nurfitriani


 
 
 
 This study aims to determine the stages that must be implemented in building a Business Intelligence System structured and appropriate in building Business Intelligence Systems in an organization, and understand the important aspects that must be considered for investment development Business Intelligence System is increasing. Business must be based on the conditions and needs of the organization in achieving the desired goals. If these conditions occur, then the decision-making process will be better and more accurate. The purpose of this study is to determine the important aspects that must be understood and prepared in using the Business Intelligence System in an organization. The method used is the explanation as well as the research library of several books, articles and other literature.
 
 
 

S2 Open Access 2016
Clusterin/Akt Up-Regulation Is Critical for GATA-4 Mediated Cytoprotection of Mesenchymal Stem Cells against Ischemia Injury

Bin Yu, Yueting Yang, Huan Liu et al.

Background Clusterin (Clu) is a stress-responding protein with multiple biological functions. Our preliminary microarray studies show that clusterin was prominently upregulated in mesenchymal stem cells (MSCs) overexpressing GATA-4 (MSCGATA-4). We hypothesized that the upregulation of clusterin is involved in overexpression of GATA-4 mediated cytoprotection. Methods MSCs harvested from bone marrow of rats were transduced with GATA-4. The expression of clusterin in MSCs was further confirmed by real-time PCR and western blotting. Simulation of ischemia was achieved by exposure of MSCs to a hypoxic environment. Lactate dehydrogenase (LDH) released from MSCs was served as a biomarker of cell injury and MTs uptake was used to estimate cell viability. Mitochondrial function was evaluated by measuring mitochondrial membrane potential (ΔΨm) and caspase 3/7 activity. Results (1) Clusterin expression was up-regulated in MSCGATA-4 compared to control MSCs transfected with empty-vector (MSCNull). MSCGATA-4 were tolerant to 72 h hypoxia exposure as shown by reduced LDH release and higher MTs uptake. This protection was abrogated by transfecting Clu-siRNA into MSCGATA-4. (2) Exogenous clusterin significantly decreased LDH release and increased MSC survival in hypoxic environment. Moreover, ΔΨm was maintained and caspase 3/7 activity was reduced by clusterin in a concentration-dependent manner. (3) p-Akt expression in MSCs was upregulated following pre-treatment with clusterin, with no change in total Akt. Moreover, cytoprotection mediated by clusterin was partially abrogated by Akt inhibitor LY294002. Conclusions Clusterin/Akt signaling pathway is involved in GATA-4 mediated cytoprotection against hypoxia stress. It is suggested that clusterin may be therapeutically exploited in MSC based therapy for cardiovascular diseases.

14 sitasi en Biology, Medicine
arXiv Open Access 2016
Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

Malik Muhammad Abdullah, Zoltan Jurek, Sang-Kil Son et al.

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit we employ a Monte-Carlo (MC)-molecular dynamics (MD)-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution we have used two different spatial beam profiles, gaussian and flattop.

en physics.atm-clus
arXiv Open Access 2016
Modeling of nanoparticle coatings for medical applications

Kaspar Haume, Nigel J. Mason, Andrey Solov'yov

Gold nanoparticles (AuNPs) have been shown to possess properties beneficial for the treatment of cancerous tumors by acting as radiosensitizers for both photon and ion radiation. Blood circulation time is usually increased by coating the AuNPs with poly(ethylene glycol) (PEG) ligands. The effectiveness of the PEG coating, however, depends on both the ligand surface density and length of the PEG molecules, making it important to understand the structure of the coating. In this paper the thickness, ligand surface density, and density of the PEG coating is studied with classical molecular dynamics using the software package MBN Explorer. AuNPs consisting of 135 atoms (approximately 1.4 nm diameter) in a water medium have been studied with the number of PEG ligands varying between 32 and 60. We find that the thickness of the coating is only weakly dependent on the surface ligand density and that the degree of water penetration increased when there is a smaller number of attached ligands.

en physics.atm-clus, physics.bio-ph
arXiv Open Access 2016
Mass spectrometric identification of C60 fragmentation regimes under energetic Cs+ bombardment

Sumaira Zeeshan, Sumera Javeed, Shoaib Ahmad

Three C60 fragmentation regimes in fullerite bombarded by Cs+ are identified as a function of its energy. C2 is the major species sputtered at all energies. For E(Cs+) < 1 keV C2 emissions dominate. C2 and C1 have highest intensities between 1 and 3 keV with increasing contributions from C3 and C4. Intensities of all fragments maximize around 2 keV. Above 3 keV, fragments densities stabilize. The roles of and the contributions from direct recoils and collision cascades are determined. Maximum direct recoil energy delivered to the C60 fullerite cage is 210 eV at which only C2 emissions occur is identified and an explanation provided. The three fragmentation regimes under continued Cs+ bombardment eventually lead to complete destruction of the C60 cages transforming fullerite into amorphous carbon

en physics.atm-clus, cond-mat.mes-hall
arXiv Open Access 2016
Electronic Non-adiabatic Dynamics in Enhanced Ionization of Isotopologues of H$_2^+$ from the Exact Factorization Perspective

E. Khosravi, A. Abedi, A. Rubio et al.

It was recently shown that the exact potential driving the electron's dynamics in enhanced ionization of H$_2^+$ can have large contributions arising from dynamical electron-nuclear correlation, going beyond what any electrostatics-based model can provide[1]. This potential is defined via the exact factorization of the molecular wavefunction that allows the construction of a Schrödinger equation for the electronic system, in which the potential contains exactly the effect of coupling to the nuclear system and any external fields. Here we study enhanced ionization in isotopologues of H$_2^+$ in order to investigate nuclear-mass-dependence of these terms for this process. We decompose the exact potential into components that naturally arise from the conditional wavefunction, and also into components arising from the marginal electronic wavefunction, and compare the performance of propagation on these different components as well as approximate potentials based on the quasi-static or Hartree approximation with the exact propagation. A quasiclassical analysis is presented to help analyse the structure of different non-electrostatic components to the potential driving the ionizing electron.

en physics.atm-clus, physics.chem-ph
S2 Open Access 2015
Development of Diagnostic Biomarkers for Detecting Diabetic Retinopathy at Early Stages Using Quantitative Proteomics

Jonghwa Jin, H. Min, S. Kim et al.

Diabetic retinopathy (DR) is a common microvascular complication caused by diabetes mellitus (DM) and is a leading cause of vision impairment and loss among adults. Here, we performed a comprehensive proteomic analysis to discover biomarkers for DR. First, to identify biomarker candidates that are specifically expressed in human vitreous, we performed data-mining on both previously published DR-related studies and our experimental data; 96 proteins were then selected. To confirm and validate the selected biomarker candidates, candidates were selected, confirmed, and validated using plasma from diabetic patients without DR (No DR) and diabetics with mild or moderate nonproliferative diabetic retinopathy (Mi or Mo NPDR) using semiquantitative multiple reaction monitoring (SQ-MRM) and stable-isotope dilution multiple reaction monitoring (SID-MRM). Additionally, we performed a multiplex assay using 15 biomarker candidates identified in the SID-MRM analysis, which resulted in merged AUC values of 0.99 (No DR versus Mo NPDR) and 0.93 (No DR versus Mi and Mo NPDR). Although further validation with a larger sample size is needed, the 4-protein marker panel (APO4, C7, CLU, and ITIH2) could represent a useful multibiomarker model for detecting the early stages of DR.

33 sitasi en Medicine

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