739 research outputs found
Kite systems of order 8;Embedding of kite systems into bowtie systems
This article consist of two parts. In the first part, we enumerate the kite systems of order 8; in the second part, we consider embedding kite systems into bowtie systems
Sustainable management applied to the metallic mining industry in Mexico : a conceptual model
PURPOSE: The metallurgical industry is an important branch of the global economy. The
activities of this industry cause ecological and social problems in Mexico. It is proposed to
elaborate and verify a conceptual model of sustainable management for Mexican Metallic
Mining Industry. Due to economic and environmental importance of this industry, the use of
adequate conceptual model of management is of crucial importance. Hence the conceptual
model is proposed.DESIGN/METHODOLOGY/APPROACH: Methodology contemplates an investigation of sustainability
inside of environmental management in Metallic Mining Industry in Mexico. The
bibliographical and theoretical information and assumptions allowed to design a conceptual
model. The model has been validated by a case study, based on the holistic single-case study.
The applied methodology consists of four steps: data acquisition and analysis, design, and
qualitative verification of the conceptual model, conclusion elaboration and the initial draft
of the best practice proposal.FINDINGS: The scope and level of implementation of selected parameters of environment
protection specified by Mexican and international law in the field, and indirectly by
analyzing the use of procedures recommended by the conceptual model, have been defined.
The conceptual model was subjected to the positive valuation of experts from the mining
industry in Mexico. The proposed conceptual model of sustainable management joins the UN
Universal Principles of Sustainable Management with Mexican legislative parameters.ORIGINALITY/VALUE: The originality of this study relies on the proposal of new conceptual
sustainable management model for the mining industry in Mexico. Until now foreign models
of sustainability have been mostly used for different internal areas. Mexico needs a strategy
of aligning business management needs with the urgent implementation of the Environmental
Agenda for the mining industry in Mexico. The model and results of its pilot implementation
in the metal mining sector of San Luis Potosí State create the foundation for strategy
definition and implementation. Final recommendation extends a possibility model to be
applied in non-metallic and metallurgy sector.peer-reviewe
Graphene Oxide Carboxymethylcellulose Nanocomposite for Dressing Materials
Sore, infected wounds are a major clinical issue, and there is thus an urgent need for novel biomaterials as multifunctional constituents for dressings. A set of biocomposites was prepared by solvent casting using different concentrations of carboxymethylcellulose (CMC) and exfoliated graphene oxide (Exf-GO) as a filler. Exf-GO was first obtained by the strong oxidation and exfoliation of graphite. The structural, morphological and mechanical properties of the composites (CMCx/Exf-GO) were evaluated, and the obtained composites were homogenous, transparent and brownish in color. The results confirmed that Exf-GO may be homogeneously dispersed in CMC. It was found that the composite has an inhibitory activity against the Gram-positive Staphylococcus aureus, but not against Gram-negative Pseudomonas aeruginosa. At the same time, it does not exhibit any cytotoxic effect on normal fibroblasts
Assessment of Olfactory Function in MAPTAssociated Neurodegenerative Disease Reveals Odor-Identification Irreproducibility as a Non-Disease-Specific, General Characteristic of Olfactory Dysfunction
Olfactory dysfunction is associated with normal aging, multiple neurodegenerative disorders, including Parkinson’s disease, Lewy body disease and Alzheimer’s disease, and other diseases such as diabetes, sleep apnea and the autoimmune disease myasthenia gravis. The wide spectrum of neurodegenerative disorders associated with olfactory dysfunction suggests different, potentially overlapping, underlying pathophysiologies. Studying olfactory dysfunction in presymptomatic carriers of mutations known to cause familial parkinsonism provides unique opportunities to understand the role of genetic factors, delineate the salient characteristics of the onset of olfactory dysfunction, and understand when it starts relative to motor and cognitive symptoms. We evaluated olfactory dysfunction in 28 carriers of two MAPT mutations (p.N279K, p.P301L), which cause frontotemporal dementia with parkinsonism, using the University of Pennsylvania Smell Identification Test. Olfactory dysfunction in carriers does not appear to be allele specific, but is strongly age-dependent and precedes symptomatic onset. Severe olfactory dysfunction, however, is not a fully penetrant trait at the time of symptom onset. Principal component analysis revealed that olfactory dysfunction is not odor-class specific, even though individual odor responses cluster kindred members according to genetic and disease status. Strikingly, carriers with incipient olfactory dysfunction show poor inter-test consistency among the sets of odors identified incorrectly in successive replicate tests, even before severe olfactory dysfunction appears. Furthermore, when 78 individuals without neurodegenerative disease and 14 individuals with sporadic Parkinson’s disease were evaluated twice at a one-year interval using the Brief Smell Identification Test, the majority also showed inconsistency in the sets of odors they identified incorrectly, independent of age and cognitive status. While these findings may reflect the limitations of these tests used and the sample sizes, olfactory dysfunction appears to be associated with the inability to identify odors reliably and consistently, not with the loss of an ability to identify specific odors. Irreproducibility in odor identification appears to be a non-disease-specific, general feature of olfactory dysfunction that is accelerated or accentuated in neurodegenerative disease. It may reflect a fundamental organizational principle of the olfactory system, which is more “error-prone” than other sensory systems
Design and implementation of a seismic Newtonian-noise cancellation system for the Virgo gravitational-wave detector
Terrestrial gravity perturbations caused by seismic fields produce the
so-called Newtonian noise in gravitational-wave detectors, which is predicted
to limit their sensitivity in the upcoming observing runs. In the past, this
noise was seen as an infrastructural limitation, i.e., something that cannot be
overcome without major investments to improve a detector's infrastructure.
However, it is possible to have at least an indirect estimate of this noise by
using the data from a large number of seismometers deployed around a detector's
suspended test masses. The noise estimate can be subtracted from the
gravitational-wave data; a process called Newtonian-noise cancellation (NNC).
In this article, we present the design and implementation of the first NNC
system at the Virgo detector as part of its AdV+ upgrade. It uses data from 110
vertical geophones deployed inside the Virgo buildings in optimized array
configurations. We use a separate tiltmeter channel to test the pipeline in a
proof-of-principle. The system has been running with good performance over
months
The First Data Release of CNIa0.02 -- A Complete Nearby (Redshift <0.02) Sample of Type Ia Supernova Light Curves
The CNIa0.02 is a complete, nearby sample of Type Ia supernova (SN Ia)
multiband light curves, and it is volume-limited with host-galaxy redshift
z_host<0.02. The scientific goal of CNIa0.02 is to infer the distributions of
key properties (e.g., the luminosity function) of local SNe Ia in a complete
and unbiased fashion in order to study SN explosion physics. We
spectroscopically classify any SN candidate detected (discovered or recovered)
by the All-Sky Automated Survey for Supernovae (ASAS-SN) that reaches peak
brightness <16.5 mag. Since ASAS-SN scans the full sky and does not target
specific galaxies, the sample is effectively unbiased by host-galaxy
properties. We obtain multiband photometric observations starting from the time
of discovery. In the first data release (DR1), we present the optical light
curves obtained for 240 SNe (including 182 with multiband data), and we derive
parameters such as the peak fluxes and dm15.Comment: to be submitte
Fast and Not-so-Furious: Case Study of the Fast and Faint Type IIb SN 2021bxu
We present photometric and spectroscopic observations and analysis of
SN~2021bxu (ATLAS21dov), a low-luminosity, fast-evolving Type IIb supernova
(SN). SN~2021bxu is unique, showing a large initial decline in brightness
followed by a short plateau phase. With
during the plateau, it is at the lower end of the luminosity distribution of
stripped-envelope supernovae (SE-SNe) and shows a distinct 10 day plateau
not caused by H- or He-recombination. SN~2021bxu shows line velocities which
are at least slower than typical SE-SNe. It is
photometrically and spectroscopically similar to Type IIb SNe during the
photospheric phases of evolution, with similarities to Ca-rich IIb SNe. We find
that the bolometric light curve is best described by a composite model of shock
interaction between the ejecta and an envelope of extended material, combined
with a typical SN~IIb powered by the radioactive decay of Ni. The
best-fit parameters for SN~2021bxu include a Ni mass of , an ejecta mass of
, and an ejecta
kinetic energy of . From the fits to the properties of the extended material of
Ca-rich IIb SNe we find a trend of decreasing envelope radius with increasing
envelope mass. SN~2021bxu has on the low end compared to
SE-SNe and Ca-rich SNe in the literature, demonstrating that SN~2021bxu-like
events are rare explosions in extreme areas of parameter space. The progenitor
of SN~2021bxu is likely a low mass He star with an extended envelope.Comment: 18 pages, 15 figures, submitted to MNRA
The Most Rapidly Declining Type I Supernova 2019bkc/ATLAS19dqr
We report observations of the hydrogen-deficient supernova (SN) 2019bkc/ATLAS19dqr. With B- and r-band decline between peak and 10 days post peak of Dm10 (B) = 5.24. 0.07 mag and Dm10 (r) = 3.85. 0.10 mag, respectively, SN.2019bkc is the most rapidly declining SN I discovered so far. While its closest matches are the rapidly declining SN.2005ek and SN. 2010X, the light curves and spectra of SN.2019bkc show some unprecedented characteristics. SN.2019bkc appears "hostless," with no identifiable host galaxy near its location, although it may be associated with the galaxy cluster MKW1 at z.=.0.02. We evaluate a number of existing models of fast-evolving SNe, and we find that none of them can satisfactorily explain all aspects of SN.2019bkc observations
Towards a Muon Collider
A muon collider would enable the big jump ahead in energy reach that is
needed for a fruitful exploration of fundamental interactions. The challenges
of producing muon collisions at high luminosity and 10 TeV centre of mass
energy are being investigated by the recently-formed International Muon
Collider Collaboration. This Review summarises the status and the recent
advances on muon colliders design, physics and detector studies. The aim is to
provide a global perspective of the field and to outline directions for future
work.Comment: 118 pages, 103 figure
Towards a muon collider
A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work
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