769 research outputs found
Interaction of phenol-formaldehyde condensates with isoprene rubber
The study is concerned with the interaction between p-tertiary butyl phenol-formaldehyde condensates and isoprene rubber under conditions resembling those used in industrial vulcanization processes, and involves investigations of reaction rates, mechanisms of reactions and structures produced. The work is an extension of an earlier study (A. Fitch, Thesis for Ph.D. (C.N.A.A.), 1978).
'Model' phenol-formaldehyde condensates (2-methylol 4- tert.butyl 6-methyl phenol and the ether derived from it by thermal condensation) are shown to interact with isoprene rubber (cis-l,4-polyisoprene) to form adducts containing chroman structures. The ether reacts somewhat more quickly and more efficiently than the methylol compound. 'Lewis acid' catalysts will greatly accelerate the reaction, but cause concurrent structural isomerization of the isoprene rubber, to an extent depending on the nature of the catalyst.
In separate experiments involving only rubber and catalyst, it is found that, of the three catalysts examined, tin(II) chloride dihydrate causes extensive isomerization, tin(II) chloride (anhydrous) causes little isomerization and zinc(II) chloride (anhydrous) causes negligible isomerization, under the appropriate reaction conditions. The structural changes are evaluated, and involve cis-trans interconversions double-bond shifts, cyclization and crosslinking.
Using zinc(II) chloride as catalyst, a study is made of the effectiveness of five different polyfunctional phenol- formaldehyde condensates as vulcanizing agents for isoprene rubber. The condensates consist of 2,6-dimethylol 4-tert. butyl phenol and four of its derivatives containing different molar proportions of methylol, dibenzyl ether and diaryl methane groups. One of the derivatives is a commercially-available vulcanizing agent. Measurements of rubber-combined phenolic material and of crosslink concentrations are made at different times of reaction, and results show that the condensates containing high proportions of dibenzyl ether links are the most efficient vulcanizing agents. Efficiency may be further improved by the addition of a formaldehyde donor to suppress side-reactions. The results indicate that, in all cases, combination with the rubber occurs through chroman linkages and the crosslinks contain at least two phenolic nuclei joined by dimethylene ether or methylene links
The relation between energy consumption and developed land; a model for the metropolitan area of Barcelona
The study of the developed land and the energy consumption is part of a main project, which objective is the development of a model for the evaluation of the environmental and energy efficiency of the interaction (mobility) and land use structure (called as 'territorial functionality'), applied to the metropolitan area of Barcelona . One of the most important points of the main project is the modeling of energy consumption, and developed land produced by the territorial functionality. This paper presents the calibrations results of econometrics models (log-log) for developed land, and electricity consumption. The used information for those models was; built surface by activity (cadastre), coverings of land uses of Catalonia (CREAF), electric consumption by economic activity (CNAE), meteorological variables, and operating time of activities. The analysis was for the 164 municipalities of the metropolitan area of Barcelona. The electric consumption was analyzed in different categories of activities like as residential, industrial, trade, financial services, hotels, transport, education, public lighting, etc. The artificial area was differentiated in three categories; cadastre surface, streets, and developed land without cadastre. Overall, the results show that the extension of developed land depends (with 0.8 R2) mainly from single-family homes, followed by industrial activities, and finally sport activities. The trade activities induce a contraction of developed land, result that is consistent with agglomeration economies. The different models calibrated for energy consumption show a strong dependence (with R2 between 0.5 and 0.9) first with built surface, and second with other variables such as weather condition in the municipality (minimum temperature in summer), and average operating time of the activities (mean work time, shopping time, etc). Finally, the electric consumption by public lighting depends significantly on the developed land, representing the union between the two dimensions of the study.
Influence of compositionally induced defects on the vibrational properties of device grade Cu2ZnSnSe4 absorbers for kesterite based solar cells
This work presents a detailed analysis of the impact of compositionally induced defects on the vibrational properties of Cu2ZnSnSe4 absorbers for kesterite based solar cells. Systematic changes in the intensity of the E and B modes located around the 170, 220, and 250 cm-1 frequency regions, which involve mostly cation vibrations, were observed and analyzed in relation to the occurrence of different kinds of defect clusters involving VCu, ZnCu, ZnSn, CuZn, and SnZn point defects. Additional changes are also interpreted in terms of the appearance of SnSe, ZnSe, and CuSe-like contributions at the 185 and 250 cm-1 spectral regions, respectively. The sensitivity of the Raman measurements to the presence of these kinds of defects corroborates the potential of Raman scattering for point defect assessment in these systems. © 2015 AIP Publishing LLCPeer ReviewedPostprint (published version
Machine learning techniques for identification using mobile and social media data
Networked access and mobile devices provide near constant data generation and collection. Users, environments, applications, each generate different types of data; from the voluntarily provided data posted in social networks to data collected by sensors on mobile devices, it is becoming trivial to access big data caches. Processing sufficiently large amounts of data results in inferences that can be characterized as privacy invasive. In order to address privacy risks we must understand the limits of the data exploring relationships between variables and how the user is reflected in them. In this dissertation we look at data collected from social networks and sensors to identify some aspect of the user or their surroundings. In particular, we find that from social media metadata we identify individual user accounts and from the magnetic field readings we identify both the (unique) cellphone device owned by the user and their course-grained location. In each project we collect real-world datasets and apply supervised learning techniques, particularly multi-class classification algorithms to test our hypotheses. We use both leave-one-out cross validation as well as k-fold cross validation to reduce any bias in the results. Throughout the dissertation we find that unprotected data reveals sensitive information about users. Each chapter also contains a discussion about possible obfuscation techniques or countermeasures and their effectiveness with regards to the conclusions we present. Overall our results show that deriving information about users is attainable and, with each of these results, users would have limited if any indication that any type of analysis was taking place
Evaluation of the INECO Frontal Screening and the Frontal Assessment Battery in Peruvian patients with Alzheimer's disease and behavioral variant Frontotemporal dementia
Background: The physicians often confuse the early symptoms of Frontotemporal dementia (FTD) with Alzheimer dementia (AD), leading to misdiagnosis. There are some cognitive tests to discriminate between AD and behavioral variant FTD (bvFTD), and the INECO Frontal Screening (IFS) is a promising test for this purpose. Objective: To assess the performance of the IFS to differentiate patients with AD from patients with bvFTD, compared with the Frontal Assessment Battery (FAB). Methods: A prospective study with 117 patients of our cognitive unit (35 case-patients with AD, 34 case-patients with bvFTD, and 48 control subjects). They were submitted to the following successive phases of evaluation: 1) screening; 2) dementia diagnosis; and 3) dementia sub-type diagnosis. The IFS and FAB were blind and independently applied by one neurologist to all the participants to end of phase 1 (screening), before to the definitive diagnosis establishment. Results: bvFTD showed a lower performance than AD patients on the IFS total score (F(1, 66) = 70.10, p < 0.01) and FAB total score (F(1, 66) = 17.91, p < 0.01). The IFS and FAB showed a sensitivity of 94.12% (95%CI = 80.3–99.2) and 82.3% (95%CI = 65.4–93.2), and a specificity of 94.2% (95%CI = 80.8–99.3) and 48.5% (95%CI = 31.3, 66.1), respectively. The IFS showed significantly superior discriminatory accuracy than the FAB (AuCIFS = 0.98; AuCFAB = 0.73, p < 0.00001). Conclusion: The IFS is useful for discriminating between AD and bvFTD patients. The performance of the IFS to differentiate patients with AD from patients with bvFTD is greater than FAB.Fil: Custodio, Nilton. Instituto Peruano de Neurociencias; PerúFil: Herrera Perez, Eder. Instituto Peruano de Neurociencias; PerúFil: Lira, David. Instituto Peruano de Neurociencias; PerúFil: Roca, María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt.; ArgentinaFil: Manes, Facundo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt.; Argentina. Australian Research Council; AustraliaFil: Báez Buitrago, Sandra Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt.; ArgentinaFil: Torralva, Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt.; Argentina. Australian Research Council; Australi
Network slicing games: enabling customization in multi-tenant mobile networks
Network slicing to enable resource sharing among multiple tenants-network operators and/or services-is considered as a key functionality for next generation mobile networks. This paper provides an analysis of a well-known model for resource sharing, the share-constrained proportional allocation mechanism, to realize network slicing. This mechanism enables tenants to reap the performance benefits of sharing, while retaining the ability to customize their own users' allocation. This results in a network slicing game in which each tenant reacts to the user allocations of the other tenants so as to maximize its own utility. We show that, for elastic traffic, the game associated with such strategic behavior converges to a Nash equilibrium. At the Nash equilibrium, a tenant always achieves the same or better performance than that of a static partitioning of resources, thus providing the same level of protection as static partitioning. We further analyze the efficiency and fairness of the resulting allocations, providing tight bounds for the price of anarchy and envy-freeness. Our analysis and extensive simulation results confirm that the mechanism provides a comprehensive practical solution to realize network slicing. Our theoretical results also fills a gap in the analysis of this resource allocation model under strategic players.The work of P. Caballero and G. De Veciana was supported in part by Cisco through a gift. The work of A. Banchs was supported in part by the H2020 5G-MoNArch Project under Grant 761445 and in part by the 5GCity Project of the Spanish Ministry of Economy and Competitiveness under Grant TEC2016-76795-C6-3-R
DeepCog: cognitive network management in sliced 5G Networks with deep learning
Proceeding of: 2019 IEEE International Conference on Computer Communications (IEEE INFOCOM 2019), Paris (France), 29 April - 2 May, 2019.Network slicing is a new paradigm for future 5G
networks where the network infrastructure is divided into slices
devoted to different services and customized to their needs.
With this paradigm, it is essential to allocate to each slice the
needed resources, which requires the ability to forecast their
respective demands. To this end, we present DeepCog, a novel
data analytics tool for the cognitive management of resources
in 5G systems. DeepCog forecasts the capacity needed to accommodate
future traffic demands within individual network
slices while accounting for the operator’s desired balance between
resource overprovisioning (i.e., allocating resources exceeding
the demand) and service request violations (i.e., allocating less
resources than required). To achieve its objective, DeepCog hinges
on a deep learning architecture that is explicitly designed for
capacity forecasting. Comparative evaluations with real-world
measurement data prove that DeepCog’s tight integration of
machine learning into resource orchestration allows for substantial
(50% or above) reduction of operating expenses with
respect to resource allocation solutions based on state-of-theart
mobile traffic predictors. Moreover, we leverage DeepCog
to carry out an extensive first analysis of the trade-off between
capacity overdimensioning and unserviced demands in adaptive,
sliced networks and in presence of real-world traffic.The work of University Carlos III of Madrid was supported
by the H2020 5G-MoNArch project (Grant Agreement No.
761445) and the work of NEC Laboratories Europe by the 5GTransformer
project (Grant Agreement No. 761536). The work
of CNR-IEIIT was partially supported by the ANR CANCAN
project (ANR-18-CE25-0011)
seq2R: an R package to detect change points in DNA sequences
Identifying the mutational processes that shape the nucleotide composition of the mitochondrial genome (mtDNA) is fundamental to better understand how these genomes evolve. Several methods have been proposed to analyze DNA sequence nucleotide composition and skewness, but most of them lack any measurement of statistical support or were not developed taking into account the specificities of mitochondrial genomes. A new methodology is presented, which is specifically developed for mtDNA to detect compositional changes or asymmetries (AT and CG skews) based on nonparametric regression models and their derivatives. The proposed method also includes the construction of confidence intervals, which are built using bootstrap techniques. This paper introduces an R package, known as seq2R, that implements the proposed methodology. Moreover, an illustration of the use of seq2R is provided using real data, specifically two publicly available complete mtDNAs: the human (Homo sapiens) sequence and a nematode (Radopholus similis) mitogenome sequence.Ministerio de Ciencia e Innovación | Ref. MTM2011-23204Ministerio de Ciencia e Innovación | Ref. PID2020-118101GB-I00Xunta de Galicia | Ref. 10PXIB 300 068 P
Profile and reproductive roles of seminal plasma melatonin of boar ejaculates used in artificial insemination programs
Melatonin (MLT) is present in seminal plasma (SP) of mammalian species, including pigs, and it is credited with antioxidant properties. This study aims to identify the sources of variation and the role of boar SP MLT on sperm quality and functionality and in vivo fertilizing ability of liquid-stored semen doses used in AI programs. The SP MLT was measured using an ELISA kit in a total of 219 ejaculates collected from 76 boars, and reproductive records of 5,318 AI sows were recorded. Sperm quality was assessed according to motility (computer-aided sperm analysis) and viability (cytometry evaluation). Sperm functionality was assessed according to the cytometric determination of intracellular H2O2 generation, total and mitochondrial O2- production, and lipid peroxidation in liquid AI semen samples stored at 17°C over 144 h. The concentration of SP MLT differed among seasons (P < 0.01) and day length periods (P < 0.001) of the year, demonstrating that the ejaculates collected during the increasing day length period (9.80 ± 1.38 pg/mL, range: 2.75–21.94) had lower SP MLT concentrations than those collected during the decreasing day length period (16.32 ± 1.67 pg/mL, range: 5.02–35.61). The SP MLT also differed (P < 0.001) among boars, among ejaculates within boar, and among portions within the ejaculate, demonstrating that SP from the first 10 mL of sperm-rich ejaculate fraction (SRF) exhibited lower MLT concentrations than post-SRF. The SP MLT was negatively related (P < 0.001) to mitochondrial O2- production in viable sperm. The SP MLT did not differ among AI boars (n = 14) hierarchically grouped according to high and low fertility outcomes. In conclusion, SP MLT concentration in AI boars varies depending on the season of ejaculate collection and differs among boars, ejaculates within boar, and portions within ejaculate. The SP MLT may act at the mitochondrial level of sperm by reducing the generation of O2-. However, this antioxidant role of SP MLT was not reflected in sperm quality or in vivo fertility outcomes of AI semen doses
Infrequent physeal wrist injury of the ulna and radius: a case report
We describe the case of a 13-year-old patient with a left wrist physeal fracture of the ulna and radius. X-Ray showed a Salter–Harris type II injury of the radius, and CT and MRI identified the following: type II epiphysiolysis of the radius with a metaphyseal wedge and type IV fracture of the ulna, with interposition in the focus of the fracture of the extensor carpi ulnaris tendon, as well as a tear in the central area of the triangular fibrocartilage complex. All these injuries were checked intraoperatively during open reduction. We believe that this clinical case illustrates the importance of carefully assessing physeal wrist injuries when they occur, especially in those cases involving the ulna and the radius. Diagnostic methods such as CT and MRI scans are indispensable for through evaluation and treatment of the injury
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