6,884 research outputs found
A study of poultry processing plant noise characteristics and potential noise control techniques
The noise environment in a typical poultry processing plant was characterized by developing noise contours for two representative plants: Central Soya of Athens, Inc., Athens, Georgia, and Tip Top Poultry, Inc., Marietta, Georgia. Contour information was restricted to the evisceration are of both plants because nearly 60 percent of all process employees are stationed in this area during a normal work shift. Both plant evisceration areas were composed of tile walls, sheet metal ceilings, and concrete floors. Processing was performed in an assembly-line fashion in which the birds travel through the area on overhead shackles while personnel remain at fixed stations. Processing machinery was present throughout the area. In general, the poultry processing noise problem is the result of loud sources and reflective surfaces. Within the evisceration area, it can be concluded that only a few major sources (lung guns, a chiller component, and hock cutters) are responsible for essentially all direct and reverberant sound pressure levels currently observed during normal operations. Consequently, any effort to reduce the noise problem must first address the sound power output of these sources and/or the absorptive qualitities of the room
Modeling Potential Energy of the Gaussian Gun
The Gaussian gun is an arrangement of magnets and ball bearings (pictured in Fig. 1) such that—when the leftmost ball is released—the rightmost ball is ejected at high speeds. The device has been described in several articles on energy education. The sudden appearance of kinetic energy offers a productive context for considering a range of challenging ideas: the often-counterintuitive relationship between force and potential energy, the escape velocity for attractive forces, why energy is required to break bonds, and why energy is released when bonds form. Beyond these ideas, it is also useful for motivating the representation of a potential well and bound states for both quantum mechanics and chemistry
A quantum mechanical model of the upper bounds of the cascading contribution to the second hyperpolarizability
Microscopic cascading of second-order nonlinearities between two molecules
has been proposed to yield an enhanced third-order molecular nonlinear-optical
response. In this contribution, we investigate the two-molecule cascaded second
hyperpolarizability and show that it will never exceed the fundamental limit of
a single molecule with the same number of electrons as the two-molecule system.
We show the apparent divergence behavior of the cascading contribution to the
second hyperpolarizability vanishes when properly taking into account the
intermolecular interactions. Although cascading can never lead to a larger
nonlinear-optical response than a single molecule, it provides alternative
molecular design configurations for creating materials with large third-order
susceptibilities that may be difficult to design into a single molecule.Comment: 13 pages, 9 figures, 1 tabl
Multiple gene aberrations and breast cancer: lessons from super-responders.
BackgroundThe presence of multiple molecular aberrations in patients with breast cancer may correlate with worse outcomes.Case presentationsWe performed in-depth molecular analysis of patients with estrogen receptor-positive, HER2-negative, hormone therapy-refractory breast cancer, who achieved partial or complete responses when treated with anastrozole and everolimus. Tumors were analyzed using a targeted next generation sequencing (NGS) assay in a Clinical Laboratory Improvement Amendments laboratory. Genomic libraries were captured for 3,230 exons in 182 cancer-related genes plus 37 introns from 14 genes often rearranged in cancer and sequenced to high coverage. Patients received anastrozole (1 g PO daily) and everolimus (5 or 10 mg PO daily). Thirty-two patients with breast cancer were treated on study and 5 (16 %) achieved a partial or complete response. Primary breast tissue was available for NGS testing in three of the responders (partial response with progression free survival of 11 and 14 months, respectively; complete response with progression free survival of 9+ months). The following molecular aberrations were observed: PTEN loss by immunohistochemistry, CCDN1 and FGFR1 amplifications, and PRKDC re-arrangement (NGS) (patient #1); PIK3CA and PIK3R1 mutations, and CCDN1, FGFR1, MYC amplifications (patient #2); TP53 mutation, CCNE1, IRS2 and MCL1 amplifications (patient #3). Some (but not all) of these aberrations converge on the PI3K/AKT/mTOR pathway, perhaps accounting for response.ConclusionsPatients with estrogen receptor-positive breast cancer can achieve significant responses on a combination of anastrozole and everolimus, even in the presence of multiple molecular aberrations. Further study of next generation sequencing-profiled tumors for convergence and resistance pathways is warranted
Gaussian-Charge Polarizable Interaction Potential for Carbon Dioxide
A number of simple pair interaction potentials of the carbon dioxide molecule
are investigated and found to underestimate the magnitude of the second virial
coefficient in the temperature interval 220 K to 448 K by up to 20%. Also the
third virial coefficient is underestimated by these models. A rigid,
polarizable, three-site interaction potential reproduces the experimental
second and third virial coefficients to within a few percent. It is based on
the modified Buckingham exp-6 potential, an anisotropic Axilrod-Teller
correction and Gaussian charge densities on the atomic sites with an inducible
dipole at the center of mass. The electric quadrupole moment, polarizability
and bond distances are set to equal experiment. Density of the fluid at 200 and
800 bars pressure is reproduced to within some percent of observation over the
temperature range 250 K to 310 K. The dimer structure is in passable agreement
with electronically resolved quantum-mechanical calculations in the literature,
as are those of the monohydrated monomer and dimer complexes using the
polarizable GCPM water potential. Qualitative agreement with experiment is also
obtained, when quantum corrections are included, for the relative stability of
the trimer conformations, which is not the case for the pair potentials.Comment: Error in the long-range correction fixed and three-body dispersion
introduced. 32 pages (incl. title page), 7 figures, 9 tables, double-space
Teaching Higher Education Courses in Further Education Colleges
It can be comprehended that the models and theories which are currently used to reinforce teaching depict the education practices of transmitting knowledge from teacher to students, which is more traditional, linear, input-output construction of teaching that has dominated adult education for decades including the last half century. As numerous studies (e.g. QAA, 2018) emphasizes that both the needs of learner and learning in enterprise and entrepreneurship education (EEE) context is different from other disciplines and mainstream higher education (HE). This requires further development of teaching methods and practices that can encourage the aspirations of the learner in this particular education setting. When investigating the theories and approaches that are used to examine teaching in HE, the relevance and adequacy of them to review teaching practices in this 21st century and EEE context is a question. Thus, the need of new theoretical models and frameworks can be clearly observed. For example, to investigate teacher’s role in EEE setting, there is a need of adopting more context specific, individual-focused research methods.
When the recent outcomes associated with the UK higher education are taken into account, there is an emerging key debate; i.e. are universities actually turning off potential entrepreneurs. Whether these outcomes are due to teaching, learning environment or other activities within universities, is still largely a question, hence requires further research to find answers
High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis
We present a generic approach for treating the effect of nuclear motion in
the high-order harmonic generation from polyatomic molecules. Our procedure
relies on a separation of nuclear and electron dynamics where we account for
the electronic part using the Lewenstein model and nuclear motion enters as a
nuclear correlation function. We express the nuclear correlation function in
terms of Franck-Condon factors which allows us to decompose nuclear motion into
modes and identify the modes that are dominant in the high-order harmonic
generation process. We show results for the isotopes CH and CD and
thereby provide direct theoretical support for a recent experiment [Baker {\it
et al.}, Science {\bf 312}, 424 (2006)] that uses high-order harmonic
generation to probe the ultra-fast structural nuclear rearrangement of ionized
methane.Comment: 6 pages, 6 figure
Molecular Dynamics Simulation of Polymer-Metal Bonds
Molecular simulation is becoming a very powerful tool for studying dynamic phenomena in materials. The simulation yields information about interaction at length and time scales unattainable by experimental measurements and unpredictable by continuum theories. This is especially meaningful when referring to bonding between a polymer and a metal substrate. A very important characteristic of polymers is that their physical properties do not rely on the detailed chemical structure of the molecular chains but only on their flexibility, and accordingly they will be able to adopt different conformations. In this paper, a molecular simulation of the bonding between vinyl ester polymer and steel is presented. Four different polymers with increasing chain lengths have been studied. Atomic co-ordinates are adjusted in order to reduce the molecular energy. Conformational changes in the macromolecules have been followed to obtain the polymer pair correlation function. Radius of gyration and end-to-end distance distributions of the individual chains have been used as a quantitative measurement of their flexibility. There exists a correlation between flexibility of the molecular chains and the energy of adhesion between the polymer and the metal substrate. Close contacts between the two materials are established at certain points but every atom up to a certain distance from the interface contributes to the total value of the adhesion energy of the system
APOE e4 genotype predicts severe COVID-19 in the UK Biobank community cohort
This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.C.L.K., L.C.P., G.A.K., and D.M. are supported in part by an R21 grant (R21AG060018) funded by National Institute on Aging, National Instute of Health, USA, UK Medical Research Council award MR/S009892/1 (PI Melzer) supports J.L.A. J.A.H.M. is supported by National Institute for Health Research, UK Doctoral Research Fellowship DRF-2014-07-177.published version, accepted version (12 month embargo), submitted versio
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