12,299 research outputs found
Rustless translation
ATP binding cassette proteins are a large and diverse family of molecular machines and include transmembrane transporter, chromosome maintenance and DNA repair proteins, and translation factors. However, the function of the ABCE1, the only member of subfamily E of ABC proteins, remained mysterious for over a decade, even though it is perhaps the most conserved ABC protein in eukaryotes and archaea. Recent results have now identified ABCE1 as the ribosome-recycling factor of eukaryotes and archaea. Thus, two iron-sulfur clusters - the hallmark feature of ABCE1 - help catalyze an integral step of the translational cycle at the core of the protein synthesis machinery
A spinose appendage fragment of a problematic arthropod from the Early Ordovician of Morocco
A highly spinose fragment of a possibly raptorial appendage from the Arenig (Early Ordovician) of the Upper Fezouata Formation north of Zagora, southeastern Morocco is described as the arthropod Pseudoangustidontus duplospineus gen. et sp. nov. The single fragmentary specimen displays a unique morphology, carrying at least 39 pairs of spines (i.e., 78 spines) of very regularly alternating lengths. Pseudoangustidontus gen. nov. shows some similarities to a number of spinose arthropod appendages and appendage parts, most notably to the spine-bearing podomeres of the third prosomal appendage of megalograptid eurypterids and the problematic and incompletely known genus Angustidon tits. However, megalograptids and Angustidontus both have a lower spine count, while the latter also carries only a single row of spines. Because no known arthropod displays a morphology closely comparable to that of Pseudoangustidontus gen. nov., the affinities of the new fossil within Arthropoda remain uncertain
Controlling service work: An ambiguous accomplishment between employees, management and customers
In order to understand the control of service work, most service literature has focused on its production while treating the customer as secondary. The consumption literature emphasizes the customer’s role but lacks empirical evidence for its claims. Using an ethnographic study of an ‘exclusive’ department store, this article aims to reduce the gap between these two bodies of literature by investigating how employees, management and customers control service work. The findings suggest that the maintenance of class difference combined with competing expectations of managers, employees and customers makes the management of service work highly ambiguous and reveals a continuing instability between managerial practices of
control and consumer culture
The recent sedimentology of Scolt Head Is., Norfolk
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Looking at the bright side - The story of AA Dor as revealed by its cool companion
Irradiation effects in close binaries are crucial for a reliable
determination of system parameters and understanding the close binary
evolution. We study irradiated light originating from the low mass component of
an eclipsing system comprising a hot subdwarf primary and a low mass companion,
to precisely interpret their high precision photometric and spectroscopic data,
and accurately determine their system and surface parameters. We re-analyse the
archival VLT/UVES spectra of AA Dor system where irradiation features have
already been detected. After removing the predominant contribution of the hot
subdwarf primary, the residual spectra reveal more than 100 emission lines from
the heated side of the secondary with maximum intensity close to the phases
around secondary eclipse. We analyse 22 narrow emission lines of the irradiated
secondary, mainly of OII, with a few CII lines. Their phase profiles constrain
the emission region of the heated side to a radius 95% of the radius of
the secondary. The shape of their velocity profiles reveals two distinct
asymmetry features one at the quadrature and the other at the secondary
eclipse. We identify more than 70 weaker emission lines originating from HeI,
NII, SiIII, CaII and MgII. We correct the radial velocity semi-amplitude of the
center-of-light to the centre-of-mass of the secondary and calculate accurate
masses of both components. The resulting masses =0.46
0.01 and =0.079 0.002 are in perfect
accordance with those of a canonical hot subdwarf primary and a low mass star
just at the substellar limit for the companion. We compute a first generation
atmosphere model of the irradiated low mass secondary, which matches the
observed spectrum well. We find an indication of an extended atmosphere of the
irradiated secondary star.Comment: 13 pages, 9 figures, accepted for publication in A&
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Students Exposure to Sustainable Thermal Energy Storage Technologies at West Texas A&M University
In the mechanical and civil engineering programs at West
Texas A&M University, students are exposed to a variety
of sustainability-oriented projects through senior design
and research courses. The projects are selected to provide
an in-depth understanding of the investigated area through
analytical and experimental studies. In this particular
project, students in thermal design were asked to
investigate the feasibility of using paraffin-oil mixture as a
phase change material (PCM) in residential walls. A PCM
material with a melting point of 23°C (73°F) was designed
and mixed. The mass of PCM required for a 1 m2 (10.8 ft2)
wall (the size of the test apparatus) was determined to be
5.8 kg (12.8 lb) in a vertical 3.18 cm (1.25 in) thick sheet.
A wall containing the PCM and another wall designated as
a “control” were placed on 1 meter cubic insulated
structures and were monitored through controlled
experimentation. The testing was conducted indoors and an
interior heating element simulated four complete day
cycles. The result of the indoor study proved conclusively
that with the correct modifications and optimization, PCM,
as a form of insulation, is economically viable over its
lifespan of 20 years. The reduced cost to the owner of a 186
m2 (2,000 ft2) home is $129.73/year. The proposed design
causes a minuscule 5.76 kg/m2 (1.2 lb/ft2) of additional
load to the structure. Because the PCM is in the
configuration of a uniform sheet, the majority of the extra
load will be supported by the concrete slab of the home.Cockrell School of Engineerin
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