3,374 research outputs found
Energy dependence of non-local potentials
Recently a variety of studies have shown the importance of including
non-locality in the description of reactions. The goal of this work is to
revisit the phenomenological approach to determining non-local optical
potentials from elastic scattering. We perform a analysis of neutron
elastic scattering data off Ca, Zr and Pb at energies MeV, assuming a Perey and Buck or Tian, Pang, and Ma non-local
form for the optical potential. We introduce energy and asymmetry dependencies
in the imaginary part of the potential and refit the data to obtain a global
parameterization. Independently of the starting point in the minimization
procedure, an energy dependence in the imaginary depth is required for a good
description of the data across the included energy range. We present two
parameterizations, both of which represent an improvement over the original
potentials for the fitted nuclei as well as for other nuclei not included in
our fit. Our results show that, even when including the standard Gaussian
non-locality in optical potentials, a significant energy dependence is required
to describe elastic-scattering data.Comment: 6 pages, 3 figures, accepted by Phys. Rev. C Rapid Communicatio
One-nucleon transfer reactions and the optical potential
We provide a summary of new developments in the area of direct reaction
theory with a particular focus on one-nucleon transfer reactions. We provide a
status of the methods available for describing (d,p) reactions. We discuss the
effects of nonlocality in the optical potential in transfer reactions. The
results of a purely phenomenological potential and the optical potential
obtained from the dispersive optical model are compared; both point toward the
importance of including nonlocality in transfer reactions explicitly. Given the
large ambiguities associated with optical potentials, we discuss some new
developments toward the quantification of this uncertainty. We conclude with
some general comments and a brief account of new advances that are in the
pipeline.Comment: 7 pages, 5 figures, proceedings for the 14th International Conference
on Nuclear Reaction Mechanisms, Varenna, June 201
Assembling large, complex environmental metagenomes
The large volumes of sequencing data required to sample complex environments
deeply pose new challenges to sequence analysis approaches. De novo metagenomic
assembly effectively reduces the total amount of data to be analyzed but
requires significant computational resources. We apply two pre-assembly
filtering approaches, digital normalization and partitioning, to make large
metagenome assemblies more comput\ ationaly tractable. Using a human gut mock
community dataset, we demonstrate that these methods result in assemblies
nearly identical to assemblies from unprocessed data. We then assemble two
large soil metagenomes from matched Iowa corn and native prairie soils. The
predicted functional content and phylogenetic origin of the assembled contigs
indicate significant taxonomic differences despite similar function. The
assembly strategies presented are generic and can be extended to any
metagenome; full source code is freely available under a BSD license.Comment: Includes supporting informatio
Reactivity of Allenes towards Iron Carbonyl Complexes
A series of monosubstituted allenes was reacted with Fe2(CO)9 to give dinuclear iron-carbonyl complexes containing organic ligands derived either from monomeric or dimerized allene. A mechanism of formation is proposed based on isolated intermediates. These intermediates point to an allene dimerization via addition of a reactive allene iron complex to free allene. Unusual chemical shifts were observed for many resonances in the 1H- and 13C-NMR spectra of the new compounds
Electronic and optical properties of beryllium chalcogenides/silicon heterostructures
We have calculated electronic and optical properties of
Si/BeSeTe heterostructures by a semiempirical
tight-binding method. Tight-binding parameters and band bowing of
BeSeTe are considered through a recent model for highly
mismatched semiconductor alloys. The band bowing and the measurements of
conduction band offset lead to a type II heterostucture for
Si/BeSeTe with conduction band minimum in the Si layer and
valence band maximum in the BeSeTe layer. The electronic
structure and optical properties of various (Si/(BeSeTe [001] superlattices have been considered. Two
bands of interface states were found within the bandgap of bulk Si. Our
calculations indicate that the optical edges are below the fundamental bandgap
of bulk Si and the transitions are optically allowed.Comment: 16 pager, 7 figure
Does Insurance Sector Matter for Economic Complexity?
The study examines the impact of the insurance market on economic complexity in 28 OECD nations within a period of 1995–2020. The study also examines whether the impact of life insurance on economic complexity would be different from that of the non-life insurance sector within the insurance market. The results based on pooled mean group (PMG) estimators reveal that the insurance sector influences economic complexity positively. This finding is further substantiated after employing panel co-integrating regression and method of moment quantile regression (MM-QR). The study concludes that the insurance sector is a key instrument in upgrading the economic complexity of an economy. Since the distributional impact of economic complexity also depends on economic and financial risk, the insurance sector can assist in mitigating the risks and uphold the productive knowledge structure needed to enhance national product sophistication
Perlindungan Hukum Bagi Konsumen Air Minum Atas Layanan Pdam Tirta Siak Kota Pekanbaru Ditinjau dari Undang-undang Nomor 8 Tahun 1999 Tentang Perlindungan Konsumen
Among the complaints of the customers are the taps until the water quality is very bad home-home even unfit for consumption as drinking water or for cooking. We each month to pay the bills that do not fit with the water that we use. We hold water and be spilled and dumped because the water is dirty, smelly and sometimes the smell of garbage. From the first, as this issue continues to be present when talking about PDAM Pekanbaru. Customers upset because they feel disadvantaged by poor water quality especially when it rains. But, until now there is no fix for this problem. Even changing penguasapun in Pekanbaru not bring good changes to the quality of service to consumers.This study using sociological juridical approach. Sociological juridical research or empirical research approach is to look at in terms of the fact that occur in the field. While the descriptive nature of the research is aimed at providing a clear picture of the issues examined. Population and sample in this study is a population study in PDAM Tirta Siak Pekanbaru City and sample the Director of PDAM Tirta Siak Pekanbaru and Consumer Services Drinking Water Using Tirta Siak Pekanbaru in Pekanbaru District of the City.The results of this study are: First, the law for the protection of drinking water consumers for services PDAM Tirta Siak Pekanbaru city on water quality is very bad, resulting in non-fulfillment of the rights of consumers, resulting in harm to consumers both Financial and nonfinancial. Second, the recognition of the people who use the water utility PDAM TirtaSiak Pekanbaru, the absence of realized what strived by PDAM TirtaSiak Pekanbaru City until recently, even the water quality is getting worse. If rainy days, the water supplied by PDAM Tirta Siak Pekanbaru City unfit for dikosumsi. Legal efforts are made to consumers who are disadvantaged on layanana drinking water by PDAM Tirta Siak Pekanbaru City may file a lawsuit to the Consumer Dispute Settlement Board (BPSK) which is based on Law No. 8 of 1999 on Consumer Protection
- …