642 research outputs found
The graviton Compton mass as Dark energy
One of the greatest challenges of science is to understand the current
accelerated expansion of the Universe. In this work, we show that by
considering the quantum nature of the gravitational field, its wavelength can
be associated with an effective Compton mass. We propose that this mass can be
interpreted as dark energy, with a Compton wavelength given by the size of the
observable Universe, implying that the dark energy varies depending on this
size. If we do so, we find that: 1.- Even without any free constant for dark
energy, the evolution of the Hubble parameter is exactly the same as for the
LCDM model, so we expect this model to have the same predictions as LCDM. 2.-
The density rate of the dark energy is which is a very
similar value as the one found by the Planck satellite . 3.- The dark energy has this value because it corresponds to the actual
size of the radius of the Universe, thus the coincidence problem has a very
natural explanation. 4.-It is possible to find also a natural explanation to
why observations inferred from the local distance ladder find the value km/s/Mpc for the Hubble constant. We show that if we take the variability
of the dark energy into account, they should measure km/s/Mpc as
well. 5.-In this model the inflationary period contains a natural successful
graceful exit.Comment: Work based on a presentation at the congress IWARA202
Chameleon perfect scalar field as a geometric correction in gravity
In this work, we derive the analytical form for a model that describes
a perfect scalar field by assuming the existence of a chameleon
mechanism. Based on four statements, at the background and perturbative level,
it is possible to relate the extra terms from this theory as a geometrical
perfect fluid term, whose has been expressed as possible candidates to explain
the nature of the dark sector, and possibly, in the case of a perfect scalar
chameleon during inflation, satisfy the big bang nucleosynthesis (BBN)
constraints until late times.Comment: 9 pages. Contribution to "Gravity, Cosmology and Astrophysics - A
Journey of Exploration and Discovery with Female Pioneers". Springer Natur
Midfacial fractures: our experience.
Authors report their experience in the treatment of midfacial fractures in 201 patients, 177 of whom underwent surgery for reduction and fixation of the fracture. Since no functional or aesthetic deficits were present, surgery was not performed in the remaining 24 cases. Of the 177 patients, the maxillary complex was involved in 70 (classified as central and centro- lateral fractures), the zygomatic-maxillary-orbital complex in another 70, isolated fractures of the orbital floor blow-out in 18, and. isolated fractures of the zygomatic arch in 19. The re- sults obtained and the degree of satisfaction were evaluated in 90 patients with clinical visits, as well as by telephone inter- view. A total of 88 patients expressed complete satisfaction with the results of the surgical outcome, while the remaining 2 patients were not satisfied with the aesthetic outcome. All pa- tients were operated within 24-48 hours post-trauma in the case of incarceration of extrinsic ocular muscles, and within 10 days in other types of trauma, even in those patients in inten- sive care. The importance of clinical and radiological pre-op- erative diagnosis is stressed as well as the choice of the most suitable therapeutic approach for the different types of frac- tures, considering recent tendencies towards minimally inva- sive procedures to achieve better cosmetic results. The latest developments in fixation techniques with reference to titanium mini- and/or micro-plates that may eventually be substituted with absorbable materials are discussed
Watermarking strategies for IP protection of micro-processor cores
L. Parrilla, E. Castillo, U. Meyer-BĂ€se, A. GarcĂa, D. GonzĂĄlez, E. Todorovich, E. Boemo, A. Lloris, "Watermarking strategies for IP protection of micro-processor cores", Proceedings of SPIE 7703, Independent Component Analyses, Wavelets, Neural Networks, Biosystems, and Nanoengineering VIII, 77030L (2010). Copyright 2010 Society of PhotoâOptical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.Reuse-based design has emerged as one of the most important methodologies for integrated circuit design, with reusable Intellectual Property (IP) cores enabling the optimization of company resources due to reduced development time and costs. This is of special interest in the Field-Programmable Logic (FPL) domain, which mainly relies on automatic synthesis tools. However, this design methodology has brought to light the intellectual property protection (IPP) of those modules, with most forms of protection in the EDA industry being difficult to translate to this domain. However, IP core watermarking has emerged as a tool for IP core protection. Although watermarks may be inserted at different levels of the design flow, watermarking Hardware Description Language (HDL) descriptions has been proved to be a robust and secure option. In this paper, a new framework for the protection of ÎŒP cores is presented. The protection scheme is derived from the IPP@HDL procedure and it has been adapted to the singularities of ÎŒP cores, overcoming the problems for the digital signature extraction in such systems. Additionally, the feature of hardware activation has been introduced, allowing the distribution of ÎŒP cores in a "demo" mode and a later activation that can be easily performed by the customer executing a simple program. Application examples show that the additional hardware introduced for protection and/or activation has no effect over the performance, and showing an assumable area increase.This work was partially funded by project TEC2007-68074-C02-01/MIC (Plan Nacional I+D+I, Spain). CAD tools and
supporting material were provided by Altera Corp. trough University Program agreements. Any opinions, findings, and
conclusions or recommendations expressed in this paper are those of the authors and do not necessarily reflect the views
of the sponsors
New insights into the exploitation of vitis vinifera l. Cv. aglianico leaf extracts for nutraceutical purposes
The leaves of Vitis vinifera L. have been used for a long time in traditional medicine for the treatment of many ailments. Grape polyphenols, indeed, have been demonstrated to be able to defend against oxidative stress, responsible for various disorders such as cancer, diabetes and neurodegenerative diseases. The effects of different extraction techniques, Soxhlet (SOX), Accelerated Solvent (ASE 40, ASE 50) and Ultrasound Assisted Extraction (UAE) were studied in this work to evaluate their impact on the chemical profile and bioactive potential of Vitis vinifera L. (cv. Aglianico) leaf extracts. The phytochemical profile was investigated by HPLC-DAD and 9 phenolic compounds were identified and quantified in the extract. Moreover, the antioxidant, anticholinesterase and antityrosinase activities were evaluated. In detail, the total polyphenol content and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, Oxygen Radical Absorbance Capacities and ÎČ-Carotene Bleaching assays) were evaluated and compared to assess the Relative Antioxidant Capacity Index (RACI). To test the inhibitory activity of extracts towards cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition assays were performed. SOX and ASE 50 have shown the highest value of RACI, 0.76 and 0.65, respectively. Regarding enzymatic inhibitory activity, ASE 50 (IC50 = 107.16 ± 8.12 ”g/mL) and SOX (IC50 = 171.34 ± 12.12 ”g/mL) extracts exhibited the highest AChE and BChE inhibitory activity, respectively, while UAE (IC50 = 293.2 ± 25.6 ”g/mL, followed by SOX (IC50 = 302.5 ± 38.3 ”g/mL) showed the highest tyrosinase inhibition value. Our results demonstrated for the first time that Aglianico leaves are important sources of phenols that could be used to prevent oxidative stress and be potentially helpful in diseases treatable with tyrosinase and cholinesterase inhibitors, like myasthenia gravis or Alzheimerâs
The first report of Tityus (Scorpiones: Buthidae) in AnzoĂĄtegui State, Venezuela: a new species
Tityus gonzalespongai n. sp. is a species endemic to the high mountains of AnzoĂĄtegui State, Venezuela. It is found between 1,600 and 2,200 m in ''La Laguna'' mountain. Its habitat includes the area of ''Bosque HĂșmedo Montano Bajo'' with the type of vegetation of ''Bosque OmbrĂłfilo Montano Siempreverde'' (''Bosques Nublados Costeros'' that includes the ''SubpĂĄramos Arbustivos''). It is distinguished from other Tityus species (T. caripitensis, T. monaguensis, and T. nororientalis) by the following characteristics: 1- the disposition of the trichobothria in the pedipalps; 2- ventral keels of the caudal segments of the metasoma (segment II, double and parallel in the proximal two thirds, then convergent and finally divergent in the base; segments III and IV, double and parallel in the basal third, then convergent in a single keel that divides in the base); 3- the number of lines of denticles of the movable finger of the right pedipalp (male = 14; female = 14); 4- pectineous teeth (right/left: male = 15/15: female = 16/15); 5- color: movable and fixed fingers dark brown; prosoma and metasoma, ochre; caudal segment IV, slightly darker than the previous ones; V and the telson, dark brown. T. gonzalespongai belongs to the ''androcottoides'' group and presents a marked sexual dimorphism. It is the first species of the Tityus genus described and reported in AnzoĂĄtegui State, expanding this taxa distribution in Venezuela
Pre-operative speech-language pathology counselling in patients undergoing total laryngectomy: A pilot randomized clinical trial
Total Laryngectomy seriously affects on patients Quality of Life and on their psychological well-being. The aim of this study was to verify the effects of pre-operative Speech-Language Pathology counselling on laryngectomized patients. Pilot randomized controlled trial. Twenty-seven patients undergoing total laryngectomy and primary tracheoesophageal puncture were randomized as follows: 14/27 subjects were collocated in the Experimental group who received preoperative Speech-Language Pathology counselling and 13/27 in the Control group group that did not receive it. Two interviews and four questionnaires (Psychological Distress Inventory, Impact of Event Scale-Revised, Hospital Anxiety and Depression Scale, Italian-Self-Evaluation of Communication Experiences after Laryngeal Cancer) were administered immediately after surgery (T0), 1- (T1) and 3-months (T2) after hospital discharge in order to asses levels of distress, post-traumatic stress and anxious-depressive symptoms, acquisition and acceptance of the new voice. Studentâs t test and chi square test showed that the two groups of patients were equivalent. Experimental group was more satisfied with the information and obtained statistically better (p < 0.05) scores in terms of levels of distress, post-traumatic stress, anxious-depressive symptoms and acceptance of the new voice than the Control group. The Speech-Language Pathology counselling may reduce the anguish, sadness and anticipatory anxiety deriving from the uncertainty of the post-operative course and it might facilitate the process of emotional adaptation, making patients more capable and prepared to face their new condition
Phytochemical Characterization and Antiplatelet Activity of Mexican Red Wines and Their By-products
Red wines and their grape pomaces are important sources of phenolic compounds. Inhibition of plateletaggregation is one of the mechanisms proposed for cardioprotective effect of phenolic compounds fromwine and grape pomace; however, phenolic content is affected by region, variety and winemaking process.In the present study, antiplatelet effect of red wines and grape pomaces was related to its phenolic content(determined by spectrophotometric techniques) and profile (determined using HPLC-MS/MS). in vitroAnti-platelet aggregation was determined using human platelets. Results showed that Zinfandel wine andCabernet Sauvignon grape pomace presented the highest phenolic content. Phenolic profiles presenteddifferences in the presence of flavonoids and oligomeric tannins. Results from platelet aggregationshowed that Merlot and Petit Verdot wines and Petit Verdot grape pomace sample presented the highestantiaggregant effect. These results indicate that antiplatelet effect could be related to phenolic profile thanphenolic content in wines and grape pomaces. Cardioprotective effect of red wines and grape pomacecould be related to specific compounds such as monomeric and polymeric flavan-3-ols
El extraordinario aumento en los partos por cesĂĄrea en Puerto Rico y su impacto sobre la esterilizaciĂłn femenina y la fecundidad
abstract in englishResumen en españo
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