12,936 research outputs found
A projective Dirac operator on CP^2 within fuzzy geometry
We propose an ansatz for the commutative canonical spin_c Dirac operator on
CP^2 in a global geometric approach using the right invariant (left action-)
induced vector fields from SU(3). This ansatz is suitable for noncommutative
generalisation within the framework of fuzzy geometry. Along the way we
identify the physical spinors and construct the canonical spin_c bundle in this
formulation. The chirality operator is also given in two equivalent forms.
Finally, using representation theory we obtain the eigenspinors and calculate
the full spectrum. We use an argument from the fuzzy complex projective space
CP^2_F based on the fuzzy analogue of the unprojected spin_c bundle to show
that our commutative projected spin_c bundle has the correct
SU(3)-representation content.Comment: reduced to 27 pages, minor corrections, minor improvements, typos
correcte
Interaction between synaptic dynamics and synaptic configuration determines the phase of the response to rhythmic inputs
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Absorptive carbon nanotube electrodes: consequences of optical interference loss in thin film solar cells.
A current bottleneck in the thin film photovoltaic field is the fabrication of low cost electrodes. We demonstrate ultrasonically spray coated multiwalled carbon nanotube (CNT) layers as opaque and absorptive metal-free electrodes deposited at low temperatures and free of post-deposition treatment. The electrodes show sheet resistance as low as 3.4 Ω □(-1), comparable to evaporated metallic contacts deposited in vacuum. Organic photovoltaic devices were optically simulated, showing comparable photocurrent generation between reflective metal and absorptive CNT electrodes for photoactive layer thickness larger than 600 nm when using archetypal poly(3-hexylthiophene) (P3HT) : (6,6)-phenyl C61-butyric acid methyl ester (PCBM) cells. Fabricated devices clearly show that the absorptive CNT electrodes display comparable performance to solution processed and spray coated Ag nanoparticle devices. Additionally, other candidate absorber materials for thin film photovoltaics were simulated with absorptive contacts, elucidating device design in the absence of optical interference and reflection.This research has received partial funding from the Flemish
Department of Economics, Science and
Innovation. J. G. Tait acknowledges partial funding from the
Natural Sciences and Engineering Research Canada. M. De
Volder acknowledges partial funding from the ERC Starting
grant 337739.This is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C5NR01119
Hysteroscopic Myomectomy: the Guidelines of the International Society for Gynecologic Endoscopy (ISGE)
Objective: With this publication, the International Society for Gynecologic Endoscopy (ISGE) aims to provide the clinicians with the recommendations arising from the best evidence currently available on hysteroscopic myomectomy (HM).
Study design: The ISGE Task Force for HM defined key clinical questions, which led the search of Medline/PubMed and the Cochrane Database. We selected and analyzed relevant English-language articles, published from January 2005 to June 2021, including original works, reviews and the guidelines previously published by the European Society for Gynecological Endoscopy (ESGE) and the American Association of Gynecologic Laparoscopists (AAGL), in which bibliographies were also checked in order to identify additional references, using the medical subject heading (MeSH) term "Uterine Myomectomy" (MeSH Unique ID: D063186) in combination with ''Myoma" (MeSH Unique ID: D009214) and ''Hysteroscopy" (MeSH Unique ID: D015907). We developed the recommendations through multiple cycles of literature analysis and expert discussion.
Results: The ISGE Task Force did develop 10 grade 1A-C and 4 grade 2A-C recommendations. For planning HM, evaluation of the uterus with saline infusion sonohysterography (SIS) or combined assessment by transvaginal ultrasound (TVUS) and diagnostic hysteroscopy is recommended (Grade 1A). The use of STEPW (Size, Topography, Extension of the base, Penetration and lateral Wall position) classification system of submucosal leiomyoma (LM) is recommended to predict the complex surgeries, incomplete removal of the LM, long operative time, fluid overload and other major complications (grade 1B). For type 0 LMs, in addition to resectoscopy (slicing technique), morcellation is recommended, being faster and having a shorter learning curve with respect to resectoscopy (grade 1C). For type 1-2 LMs, slicing technique is currently recommended (grade 1C). A fluid deficit of 1000 mL also in case of bipolar myomectomy with saline solution, in healthy women of reproductive age, contains low risk for major complications. Lower thresholds (750 mL) for fluid deficit should be considered in the elderly and in women with cardiovascular, renal or other co-morbidities (Grade 1B).
Conclusion: HM is the most effective conservative minimally invasive gynecologic intervention for submucous LM. The set of 14 ISGE recommendations can significantly contribute to the success of HM and the safety of patients for whom the choice of appropriate surgical technique, as well as the surgeon's awareness and measures to prevent complications are of the utmost importance.info:eu-repo/semantics/publishedVersio
Scale Dependence of Dark Energy Antigravity
We investigate the effects of negative pressure induced by dark energy
(cosmological constant or quintessence) on the dynamics at various
astrophysical scales. Negative pressure induces a repulsive term (antigravity)
in Newton's law which dominates on large scales. Assuming a value of the
cosmological constant consistent with the recent SnIa data we determine the
critical scale beyond which antigravity dominates the dynamics () and discuss some of the dynamical effects implied. We show that
dynamically induced mass estimates on the scale of the Local Group and beyond
are significantly modified due to negative pressure. We also briefly discuss
possible dynamical tests (eg effects on local Hubble flow) that can be applied
on relatively small scales (a few ) to determine the density and equation
of state of dark energy.Comment: Contributed talk at the 2nd Hellenic Cosmology Workshop at NOA
(Athens) Jan. 2001.To appear in the proceedings. Based on work done in
collaboration with M. Axenides and E. Florato
A topographic study on the evaluation of speech and language in the acute phase of a first stroke
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Evaluation of speech and language may help in localization of site and extension of brain lesions, particularly in the absence of other neurological signs or radiologically defined injuries. Objective: To verify what language tasks are best correlated to which brain regions, in order to develop a test for neurologists in emergency settings. Method: Thirty-seven adult first-stroke patients were submitted to cognitive and language tests, and then paired with thirty-seven healthy controls. Patients underwent CT and/or MRI for topographic correlation with test results (p<0.05). Results: All tests were able to distinguish patients from controls, but only word/sentence repetition, naming, ideomotor praxis and, non-significantly, comprehension and counting 1-20 predicted left hemisphere lesions. Repetition was related to perisylvian structures, comprehension to the posterior portion of the middle cerebral artery territory, and fluency to frontal lesions, while naming was accurate only for lesion side. Conclusion: Language and cognitive tasks can help in the localization of acute stroke lesions.695790798Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
Adaptation to high ethanol reveals complex evolutionary pathways
Tolerance to high levels of ethanol is an ecologically and industrially relevant phenotype of microbes, but the molecular mechanisms underlying this complex trait remain largely unknown. Here, we use long-term experimental evolution of isogenic yeast populations of different initial ploidy to study adaptation to increasing levels of ethanol. Whole-genome sequencing of more than 30 evolved populations and over 100 adapted clones isolated throughout this two-year evolution experiment revealed how a complex interplay of de novo single nucleotide mutations, copy number variation, ploidy changes, mutator phenotypes, and clonal interference led to a significant increase in ethanol tolerance. Although the specific mutations differ between different evolved lineages, application of a novel computational pipeline, PheNetic, revealed that many mutations target functional modules involved in stress response, cell cycle regulation, DNA repair and respiration. Measuring the fitness effects of selected mutations introduced in non-evolved ethanol-sensitive cells revealed several adaptive mutations that had previously not been implicated in ethanol tolerance, including mutations in PRT1, VPS70 and MEX67. Interestingly, variation in VPS70 was recently identified as a QTL for ethanol tolerance in an industrial bio-ethanol strain. Taken together, our results show how, in contrast to adaptation to some other stresses, adaptation to a continuous complex and severe stress involves interplay of different evolutionary mechanisms. In addition, our study reveals functional modules involved in ethanol resistance and identifies several mutations that could help to improve the ethanol tolerance of industrial yeasts
What is the impact of multimorbidity on the risk of hospitalisation in older adults? A systematic review study protocol
INTRODUCTION: The development of multiple coexisting chronic diseases (multimorbidity) is increasing globally, along with the percentage of older adults affected by it. Multimorbidity is associated with the concomitant use of multiple medications, a greater possibility of adverse effects, and increased risk of hospitalisation. Therefore, this systematic review study protocol aims to analyse the impact of multimorbidity on the occurrence of hospitalisation in older adults and assess whether this impact changes according to factors such as sex, age, institutionalisation and socioeconomic status. This study will also review the average length of hospital stay and the occurrence of hospital readmission. METHODS AND ANALYSIS: A systematic review of the literature will be carried out using the PubMed, Embase and Scopus databases. The inclusion criteria will incorporate cross-sectional, cohort and case-control studies that analysed the association between multimorbidity (defined as the presence of ≥2 and/or ≥3 chronic conditions and complex multimorbidity) and hospitalisation (yes/no, days of hospitalisation and number of readmissions) in older adults (aged ≥60 years or >65 years). Effect measures will be quantified, including ORs, prevalence ratios, HRs and relative risk, along with their associated 95% CI. The overall aim of this study is to widen knowledge and to raise reflections about the association between multimorbidity and hospitalisation in older adults. Ultimately, its findings may contribute to improvements in public health policies resulting in cost reductions across healthcare systems. ETHICS AND DISSEMINATION: Ethical approval is not required. The results will be disseminated via submission for publication to a peer-reviewed journal when complete. PROSPERO REGISTRATION NUMBER: CRD42021229328
Multivariate discrimination and the Higgs + W/Z search
A systematic method for optimizing multivariate discriminants is developed
and applied to the important example of a light Higgs boson search at the
Tevatron and the LHC. The Significance Improvement Characteristic (SIC),
defined as the signal efficiency of a cut or multivariate discriminant divided
by the square root of the background efficiency, is shown to be an extremely
powerful visualization tool. SIC curves demonstrate numerical instabilities in
the multivariate discriminants, show convergence as the number of variables is
increased, and display the sensitivity to the optimal cut values. For our
application, we concentrate on Higgs boson production in association with a W
or Z boson with H -> bb and compare to the irreducible standard model
background, Z/W + bb. We explore thousands of experimentally motivated,
physically motivated, and unmotivated single variable discriminants. Along with
the standard kinematic variables, a number of new ones, such as twist, are
described which should have applicability to many processes. We find that some
single variables, such as the pull angle, are weak discriminants, but when
combined with others they provide important marginal improvement. We also find
that multiple Higgs boson-candidate mass measures, such as from mild and
aggressively trimmed jets, when combined may provide additional discriminating
power. Comparing the significance improvement from our variables to those used
in recent CDF and DZero searches, we find that a 10-20% improvement in
significance against Z/W + bb is possible. Our analysis also suggests that the
H + W/Z channel with H -> bb is also viable at the LHC, without requiring a
hard cut on the W/Z transverse momentum.Comment: 41 pages, 5 tables, 29 figure
Water Contaminants Associated With Unconventional Oil and Gas Extraction Cause Immunotoxicity to Amphibian Tadpoles
Chemicals associated with unconventional oil and gas (UOG) operations have been shown to contaminate surface and ground water with a variety of endocrine disrupting compounds (EDCs) inducing multiple developmental alteration in mice. However, little is known about the impacts of UOG-associated contaminants on amphibian health and resistance to an emerging ranavirus infectious disease caused by viruses in the genus Ranavirus, especially at the vulnerable tadpole stage. Here we used tadpoles of the amphibian Xenopus laevis and the ranavirus Frog virus 3 (FV3) as a model relevant to aquatic environment conservation research for investigating the immunotoxic effects of exposure to a mixture of 23 UOG-associated chemicals with EDC activity. Xenopus tadpoles were exposed to an equimass mixture of 23 UOG-associated chemicals (range from 0.1 to 10 µg/l) for 3 weeks prior to infection with FV3. Our data show that exposure to the UOG chemical mixture is toxic for tadpoles at ecological doses of 5 to 10 µg/l. Lower doses significantly altered homeostatic expression of myeloid lineage genes and compromised tadpole responses to FV3 through expression of TNF-α, IL-1β, and Type I IFN genes, correlating with an increase in viral load. Exposure to a subset of 6 UOG chemicals was still sufficient to perturb the antiviral gene expression response. These findings suggest that UOG-associated water pollutants at low but environmentally relevant doses have the potential to induce acute alterations of immune function and antiviral immunity
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