3,470 research outputs found

    Description of Silvinichthys pedernalensis n. sp. (Teleostei, Siluriformes) from the Andean Cordillera of southern South America

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    Descripción de Silvinichthys pedernalensis sp. n. (Teleostei, Siluriformes) de la cordillera de los Andes en la parte meridional de Sudamérica Se describe una nueva especie, Silvinichthys pedernalensis, en un arroyo andino de la provincia de San Juan, en Argentina, a partir del patrón de coloración y caracteres merísticos, morfométricos y osteológicos. S. pedernalensis difiere notablemente de todos los demás miembros conocidos del género Silvinichthys debido a la combinación de los siguientes rasgos: ausencia de cintura y aleta pélvica, hueso supraorbital ancho, 14–18 odontoides interoperculares, 6–8 odontoides operculares, 7 radios ramificados de la aleta pectoral, 11 radios de la aleta dorsal, 7 pterigióforos de la aleta dorsal, 6 radios branquióstegos, 14 radios dorsales procurrentes de la aleta caudal y 15 ventrales, 16 costillas, 39 vértebras, pigmentación marmórea oscura de la cabeza y el cuerpo, altura de la cabeza (9,9–12,2% de la longitud estándar [LE]), ancho interorbital (28,3–36,1% de la longitud de la cabeza [LC]), longitud de la barbilla nasal (27,3–39,0% LE), longitud de la barbilla maxilar (39,5–61,7% LE), longitud de la barbilla submaxilar (24,7–41,9% LE), longitud del hocico (40,6–44,4% LC), altura del cuerpo (10,1–12,6% LE), ancho de la aleta anal (10,2–11,7% LE) y longitud del pedúnculo caudal (19,3–21,5% LE).Descripción de Silvinichthys pedernalensis sp. n. (Teleostei, Siluriformes) de la cordillera de los Andes en la parte meridional de Sudamérica Se describe una nueva especie, Silvinichthys pedernalensis, en un arroyo andino de la provincia de San Juan, en Argentina, a partir del patrón de coloración y caracteres merísticos, morfométricos y osteológicos. S. pedernalensis difiere notablemente de todos los demás miembros conocidos del género Silvinichthys debido a la combinación de los siguientes rasgos: ausencia de cintura y aleta pélvica, hueso supraorbital ancho, 14–18 odontoides interoperculares, 6–8 odontoides operculares, 7 radios ramificados de la aleta pectoral, 11 radios de la aleta dorsal, 7 pterigióforos de la aleta dorsal, 6 radios branquióstegos, 14 radios dorsales procurrentes de la aleta caudal y 15 ventrales, 16 costillas, 39 vértebras, pigmentación marmórea oscura de la cabeza y el cuerpo, altura de la cabeza (9,9–12,2% de la longitud estándar [LE]), ancho interorbital (28,3–36,1% de la longitud de la cabeza [LC]), longitud de la barbilla nasal (27,3–39,0% LE), longitud de la barbilla maxilar (39,5–61,7% LE), longitud de la barbilla submaxilar (24,7–41,9% LE), longitud del hocico (40,6–44,4% LC), altura del cuerpo (10,1–12,6% LE), ancho de la aleta anal (10,2–11,7% LE) y longitud del pedúnculo caudal (19,3–21,5% LE).Silvinichthys pedernalensis, a new species, is described from an Andean stream in Provincia San Juan, Argentina, based on its coloration pattern, and its meristic, morphometric and osteological characters. S. pedernalensis differs markedly from all other known members of the genus Silvinichthys as a result of the combination of the absence of pelvic girdle and fin, the wide supraorbital bone, the number of interopercle odontodes 14–18, the number of opercular odontodes 6–8, the branched pectoral–fin rays 7, the dorsal–fin rays 11, the number of dorsal pterygiophore 7, the branchiostegal rays 6, the dorsal procurrent caudal–fin rays 14 and ventral 15, the ribs 16, the vertebrae 39, the dark marmorated pigmentation on the body and head, the head depth 9.9–12.2% SL, the interorbital wide 28.3–36.1% HL, the nasal barbel length 27.3–39.0% SL, the maxillary barbel length 39.5–61.7% SL, the submaxillary barbel length 24.7–41.9% SL, the snout length 40.6–44.4% HL, the body depth 10.1–12.6% SL, the anal base fin 10.2–11.7% SL, and the caudal peduncle length 19.3–21.5% SL

    On the hereditary character of new strong variations of weyl type theorems

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    Berkani and Kachad [18], [19], and Sanabria et al. [32], introduced and studied strong variations of Weyl type Theorems. In this paper, we study the behavior of these strong variations of Weyl type theorems for an operator T on a proper closed and Tinvariant subspace W ⊆ X such that T n (X) ⊆ W for some n ≥ 1, where T ∈ L(X) and X is an infinite-dimensional complex Banach space. The main purpose of this paper is to prove that for these subspaces (which generalize the case T n (X) closed for some n ≥ 0), these strong variations of Weyl type theorems are preserved from T to its restriction on W and vice-versa. As consequence of our results, we give sufficient conditions for which these strong variations of Weyl type Theorems are equivalent for two given operators. Also, some applications to multiplication operators acting on the boundary variation space BV [0, 1] are given

    A note on preservation of generalized fredholm spectra in berkani’s sense

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    In this paper, we study the relationships between the spectra derived from B-Fredholm theory corresponding to two given bounded linear operators. The main goal of this paper is to obtain sufficient conditions for which the spectra derived from B-Fredholm theory corresponding to two given operators are respectively the same. Among other results, we prove that B-Fredholm type spectral properties for an operator and its restriction are equivalent, as well as obtain conditions for which B-Fredholm type spectral properties corresponding to two given operators are the same. As application of our results, we obtain conditions for which the above mentioned spectra and the spectra derived from the classical Fredholm theory are the same

    Simulation study for investment decisions on the EcoBoost camshaft machining line

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    Design/redesign of manufacturing systems is a complex, risky, and expensive task. Ford Motor Company’s Valencia Engine Plant faces this challenge as it plans to upgrade its machining and assembly lines to introduce the new EcoBoost engines. The research project described in this paper aimed to support the transition process particularly at the camshaft machining line by using simulation modelling techniques. A series of experiments was carried out using the simulation model developed, and recommendations were proposed based on the results of these experiments to support the decision as to where to invest on the line. The outcomes from the research project indicated that investment is required in terms of increasing the capacity of two bottleneck operations through retooling and improving the conveyor routing logic in one key area. Keywords: simulation modelling, closed-loop network, automotive production system

    The double-Kerr equilibrium configurations involving one extreme object

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    We demonstrate the existence of equilibrium states in the limiting cases of the double-Kerr solution when one of the constituents is an extreme object. In the `extreme-subextreme' case the negative mass of one of the constituents is required for the balance, whereas in the `extreme-superextreme' equilibrium configurations both Kerr particles may have positive masses. We also show that the well-known relation |J|=M^2 between the mass and angular momentum in the extreme single Kerr solution ceases to be a characteristic property of the extreme Kerr particle in a binary system.Comment: 12 pages, 3 figures, submitted to Class. Quantum Gra

    Critical points of higher order for the normal map of immersions in R^d

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    We study the critical points of the normal map v : NM -> Rk+n, where M is an immersed k-dimensional submanifold of Rk+n, NM is the normal bundle of M and v(m, u) = m + u if u is an element of NmM. Usually, the image of these critical points is called the focal set. However, in that set there is a subset where the focusing is highest, as happens in the case of curves in R-3 with the curve of the centers of spheres with contact of third order with the curve. We give a definition of r-critical points of a smooth map between manifolds, and apply it to study the 2 and 3-critical points of the normal map in general and the 2-critical points for the case k = n = 2 in detail. In the later case we analyze the relation with the strong principal directions of Montaldi (1986) [2]. (C) 2011 Elsevier B.V. All rights reserved.Work partially supported by CAPES (BEX 4533/06-2).Monera, M.; Montesinos-Amilibia, A.; Moraes, S.; Sanabria Codesal, E. (2012). Critical points of higher order for the normal map of immersions in R^d. Topology and its Applications. 159:537-544. https://doi.org/10.1016/j.topol.2011.09.029S53754415

    Sustainable Tourism Stewardship Council - raising the standards and benefits of sustainable tourism and ecotourism certification

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    Certification of sustainable tourism and ecotourism can help to reduce the negative environmental and social impacts of tourism, ensure that the tourism industry is held accountable and provide marketing benefits to those firms that meet the certification standards. Reports by the United Nations Environment Programme (UNEP) and the World Tourism Organization (WTO) have cited the benefits of certification and many governments, NGOs and other stakeholders are introducing national, regional and international certification programs. There is consensus that the increasing numbers of certification programs would benefit from shared functions such as marketing, training and development, while supply chains and consumers would benefit from the setting of standards. Some two years ago, the Rainforest Alliance, with funding from the Ford Foundation and help from its Advisory Committees of NGOs, multilateral agencies and industry representatives, initiated a study of the feasibility of establishing an international Sustainable Tourism Stewardship Council (STSC) to promote globally recognized, high-quality certification programs for sustainable tourism and ecotourism through a process of information sharing, marketing, and assessment of standards. (Certification is defined as the procedure by which the certification/awarding body gives written assurance and awards a logo (to the consumer and the industry in general) to signify that a product, process, service, or management system conforms to specified requirements. Accreditation is key to the role of a Stewardship Council, a body that grants certifying powers. In effect it certifies that the certifiers are doing their job correctly.) This report summarizes the findings over the two years of the study. During the study period, the authors documented growing international agreement about the need for a sound accreditation program to assess and help standardize the rapidly growing number of certification programs for the sustainable and ecotourism markets. The study involved a broad range of experts around the globe from grassroots and indigenous community activists to key tourism firms to high-level officials in UN and international environmental organizations. The need for a STSC was publicly endorsed at the World Ecotourism Summit (WES) and incorporated in its final communiqué. The Rainforest Alliance (and this project's Advisory Committees) acknowledges that certification and accreditation are not a panacea for all the problems associated with unsustainable tourism. Certification is one important tool currently being used and its merits and weaknesses must be recognized. However the study and the report presented hereby are intended to address specifically the feasibility of implementing a Stewardship Council as an accreditation organization for sustainable tourism and ecotourism certification. This report analyzes the state of the art in tourism certification and the lessons to be learned from accreditation in other sectors. Based on extensive consultation, it profiles key stakeholders and considers needs that the STSC can satisfy, and methods to do so. It proposes an organizational blueprint for a STSC that grows through a phased implementation to allow for bottom-up development of agendas and structures. It benchmarks the criteria used in certification at present to consider the feasibility of an international standard, and it also benchmarks principles and guidelines for managing tourism certification that can form the basis of accreditation criteria. As a result of the extensive consultation process, we propose three phases of development aimed at improving the quality of certification programs (and thus the sustainability of tourism) and address different issues affecting tourism certification. • Phase 1: STSC-Network to share information and gain consensus on priorities and processes. It is recommended that the STSC starts as a Network for a period of two years within which a wide range of stakeholders can consider the results of this feasibility study and the applicability in different regions, discuss the contents of a possible international standard and the necessary regional variations. The Network phase also gives tourism certification programs a vehicle to build trust and to take ownership of the systems proposed. • Phase 2: STSC-Association to market certified products, provide guidance to countries seeking to establish or upgrade certification programs, and reach agreement on standards and processes. The STSC-Association phase allows tourism certification programs and other stakeholders to agree on international standards and criteria and methods to assess how programs meet these standards, while benefiting from joint marketing and training that increases the exposure of the tourism certification programs and improves their performance. The Association phase is a necessary stepping-stone to allow tourism certification programs to make the necessary improvements to be able to meet accreditation requirements. • Phase 3: STSC-Accreditation to accredit and market certification programs that meet the agreed upon standards and demonstrate capacity to certify. This phase finally includes all key functions of the STSC by building on the agreements made at the Association phase and introducing the key element of accreditation. Structures from the Association are kept and the function of accreditation is outsourced to be able to maintain training and marketing functions separate from decision-making on which certification programs are accredited, and in doing so, guarantee independence and transparency and avoid conflicts of interest

    Microbial oil-degradation under mild hydrostatic pressure (10 MPa): which pathways are impacted in piezosensitive hydrocarbonoclastic bacteria?

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    Oil spills represent an overwhelming carbon input to the marine environment that immediately impacts the sea surface ecosystem. Microbial communities degrading the oil fraction that eventually sinks to the seafloor must also deal with hydrostatic pressure, which linearly increases with depth. Piezosensitive hydrocarbonoclastic bacteria are ideal candidates to elucidate impaired pathways following oil spills at low depth. In the present paper, we tested two strains of the ubiquitous Alcanivorax genus, namely A. jadensis KS_339 and A. dieselolei KS_293, which is known to rapidly grow after oil spills. Strains were subjected to atmospheric and mild pressure (0.1, 5 and 10?MPa, corresponding to a depth of 0, 500 and 1000?m, respectively) providing n-dodecane as sole carbon source. Pressures equal to 5 and 10?MPa significantly lowered growth yields of both strains. However, in strain KS_293 grown at 10?MPa CO2 production per cell was not affected, cell integrity was preserved and PO43- uptake increased. Analysis of its transcriptome revealed that 95% of its genes were downregulated. Increased transcription involved protein synthesis, energy generation and respiration pathways. Interplay between these factors may play a key role in shaping the structure of microbial communities developed after oil spills at low depth and limit their bioremediation potential

    Analysis of cognitive performance and polymorphisms of SORL1, PVRL2, CR1, TOMM40, APOE, PICALM, GWAS_14q, CLU, and BIN1 in patients with mild cognitive impairment and cognitively healthy controls

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    Introduction: Alzheimer disease risk polymorphisms have been studied in patients with dementia, but have not yet been explored in mild cognitive impairment (MCI) in our population; nor have they been addressed in relation to cognitive variables, which can be predictive biomarkers of disease. Objective: To evaluate cognitive performance and presence of polymorphisms of the genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE (isoforms ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN1(rs744373), and CLU(rs227959 and rs11136000) in patients with MCI and healthy individuals. Methodology: We performed a cross-sectional, exploratory, descriptive study of a prospective cohort of participants selected by non-probabilistic sampling, evaluated with neurological, neuropsychological, and genetic testing, and classified as cognitively healthy individuals and patients with MCI. Cognition was evaluated with the Neuronorma battery and analysed in relation to the polymorphic variants by means of measures of central tendency, confidence intervals, and nonparametric statistics. Results: We found differences in performance in language and memory tasks between carriers and non-carriers of BIN1, CLU, and CR1 variants and a trend towards poor cognitive performance for PICALM, GWAS_14q, SORL1, and PVRL2 variants; the APOE and TOMM40 variants were not associated with poor cognitive performance. Discussion: Differences in cognitive performance associated with these polymorphic variants may suggest that the mechanisms regulating these genes could have an effect on cognition in the absence of dementia; however, this study was exploratory and hypotheses based on these results must be explored in larger samples. Resumen: Introducción: Los polimorfismos de riesgo para el desarrollo de enfermedad de Alzheimer se han estudiado en pacientes con demencia, pero aún no se han explorado en trastorno neurocognitivo leve (TNL) en nuestra población, ni se han considerado en relación con variables cognitivas, las cuales pueden ser biomarcadores predictivos de enfermedad. Objetivo: Evaluar los desempeños cognitivos y los polimorfismos en los genes SORL1(rs11218304), PVRL2(rs6859), CR1(rs6656401), TOMM40(rs2075650), APOE(isoformas ε2, ε3, ε4), PICALM(rs3851179), GWAS_14q(rs11622883), BIN(rs744373), CLU (rs227959 y rs11136000) en pacientes con TNL y en sujetos sanos. Metodología: Estudio descriptivo, exploratorio y transversal, en una cohorte prospectiva de participantes seleccionados mediante muestreo no probabilístico, evaluados por neurología, neuropsicología y genética, y clasificados como cognitivamente sanos y pacientes con TNL, según criterios. La cognición se evaluó por medio de la batería Neuronorma y se analizó en relación con las variantes polimórficas por medio de medidas de tendencia, intervalos de confianza y estadísticos no paramétricos. Resultados: Se identificaron diferencias en los desempeños en tareas de lenguaje y memoria en relación con las variantes de BIN1, CLU y CR1, junto con tendencias en las variantes de PICALM, GWArs, SORL y PVRL2, mientras que en APOE y TOMM40 no se encontraron tendencias. Discusión: Las tendencias en los desempeños cognitivos en relación con variantes polimórficas podrían indicar que, en ausencia de demencia, los mecanismos que regulan estos genes podrían tener un efecto sobre la cognición; sin embargo, esta aproximación tiene un carácter exploratorio y sus resultados permiten generar hipótesis que requieren ser exploradas en muestras de mayor tamaño
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