1,005 research outputs found
Otenção e caracterização de organogéis de óleo de soja estruturado com ceras vegetais e gordura interesterificada obtidos sob condições controladas de cristalização
Orientador: Daniel Barrera-ArellanoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Organogéis são misturas que apresentam características de gel, compostas por agentes estruturantes e uma fase imobilizada, formando uma rede termorreversível autosustentada, onde esta fase imobilizada é um composto orgânico, o que o difere de outros géis formados basicamente por compostos hidrossolúveis. Os principais agentes estruturantes já estudados para formação de organogéis são os diacilgliceróis, monoacilgliceróis, álcoois e ácidos graxos e suas misturas, ceras e ésteres de cera, fitosteróis e orizanol, lecitina e triestearato de sorbitana, entre outros. O objetivo desta pesquisa foi desenvolver e caracterizar organogéis elaborados a partir de óleo de soja, gordura vegetal e ceras vegetais (cera de cana-de-açúcar, cera de carnaúba e cera de candelila), e a partir dos resultados obtidos gerar uma base de conhecimento para estudos posteriores sobre aplicação destes organogéis em produtos alimentícios. Organogéis estruturados com até 4% de cera vegetal (candelila, carnaúba e cana-de-açúcar) e adição de gordura vegetal nos teores de 5, 15 e 25%, os organogéis foram feitos utilizando condições controladas de cristalização (taxa de resfriamento e cisalhamento), as amostras foram analisadas quanto à estabilidade, propriedades reológicas, comportamento térmico, conteúdo de gordura sólida, dureza e morfologia. Os organogéis desenvolvidos somente com óleo de soja foram desenvolvidos para as ceras de cana-de-açúcar e candelila usando apenas cristalização estática. As análises térmicas mostraram uma temperatura de cristalização para os organogéis variando entre 43,7 e 44,57°C para a cera de cana-de-açúcar, 42,95 e 42,92°C para cera de candelila e 56,23°C para a cera de carnaúba, todas em 4% (m/m). As análises reológicas com cristalização estática mostraram que os materiais apresentaram um comportamento típico de gel com início da mudança de comportamento reológico em condições de temperatura similares às observadas na análise térmica com valores de 43,1 e 42,1°C para os géis de cana-de-açúcar e candelila respectivamente, a mesma análise para o organogel de cera de carnaúba mostrou a mudança de comportamento reológio em temperatura de aproximadamente 61°C, todos os organogéis apresentaram o comporamento esperado na varredura de frequências com os valores de G' maiores que G". As mesmas medidas feitas usando cristalização com cisalhamento em 300s-1 até a temperatura de formação de gel seguido de cristalização estática. As amostras apresentaram comportamento similar à da cristalização estática, a inclusão de gordura interesterificada por sua vez aumentou os valores de G' para as amostras, porém na análise de varredura de frequência foi observado uma maior sensibilidade à variações de frequência. A dureza foi maior para os géis de candelila, seguido dos géis de cana-de-açúcar e por últimos os de carnaúba. Os tamanhos de cristais observados na microscopia foram maiores para os organogéis de carnaúba e para os géis de cera de cana-de-açúcar quando comparados com os da cera de candelila. A formação de organogéis permitiu um aumento na estabilidade oxidativa da fase lipídica contínua. De maneira geral os organogéis apresentaram baixa resistência mecânica que foi melhorada pela inclusão da gordura vegetal, permitindo que a modificação da fase contínua amplia as possibilidades de aplicação para organogéis em produtos alimentíciosAbstract: Organogels are mixtures that present gel like characteristics, composed of a structuring agent and an immobilized phase, forming a self-sustained thermoreversible network, where this immobilized phase is an organic compound, which differs them from other gels basically formed by water-soluble compounds. The main structurant agents already studied for the formation of organogels are diacylglycerols, monoacylglycerols, alcohols, fatty acids and their mixtures, waxes and esters of wax, phytosterols and oryzanol, lecithin and sorbitan tristearate, among others. The objective of this research was to develop and characterize organogels made from soybean oil, vegetable fat and vegetable waxes (sugarcane wax, carnauba wax and candelilla wax), and from the obtained results generate a base of knowledge for further studies on the application of these organogels in food products. Organogels structured with up to 4% of vegetable wax (candelilla, carnauba and sugar cane) and addition of vegetable fat at levels of 5, 15 and 25%, the organogels were made using controlled conditions of crystallization (cooling rate And shear), the samples were analyzed for stability, rheological properties, thermal behavior, solid fat content, hardness and morphology. The organogels developed only with soybean oil were developed for sugar cane and candelilla wax using only static crystallization. Thermal analyzes showed a crystallization temperature for the organogels ranging from 43.7 to 44.57°C for sugar cane wax, 42.95 and 42.92°C for Candelilla wax and 56.23°C for carnauba wax, all at 4% (w/w). The rheological analyzes with static crystallization showed that the materials presented a typical behavior of gel with beginning of the change of rheological behavior in conditions of temperature similar to those observed in the thermal analysis with values of 43.1 and 42.1°C to The sugarcane and candelilla gels respectively, the same analysis for the carnauba wax organogel showed the change in rheological behavior at a temperature of approximately 61°C, all the organogels presented the expected behavior at the frequency sweep with values of G' greater than G". The same measurements were taken using shear crystallization in 300s-1 to the gel-forming temperature followed by static crystallization.The samples exhibited behavior similar to that of static crystallization, tha inclusion os interesterified fat increased the G' and the frequency sweep showed that it made the material more frequency sensible. The hardness was higher for the candelilla gels, followed by the sugarcane gels and the latter for the carnauba gels, the inclusion of interesterified fats increased mechanical resistance. The crystal sizes observed in the microscopy were higher for the carnauba organogens and for the sugarcane wax gels, Of sugarcane when compared to candelilla wax. The formation of organogels allowed an increase in the oxidative stability of the continuous lipid phase. All organogels presented low mechanical resistance that was improved by the inclusion of vegetable fat, allowing the modification of the continuous phase, increasing the possibilities of application for organogels in food productsDoutoradoTecnologia de AlimentosDoutor em Tecnologia de Alimentos140517/2012-0CNP
Reverse engineering of logic-based differential equation models using a mixed-integer dynamic optimization approach
9 páginas, 6 figuras.-- This is an Open Access article distributed under the terms of the Creative Commons Attribution LicenseMotivation: Systems biology models can be used to test new hypotheses formulated on the basis of previous knowledge or new experimental data, contradictory with a previously existing model. New hypotheses often come in the shape of a set of possible regulatory mechanisms. This search is usually not limited to finding a single regulation link, but rather a combination of links subject to great uncertainty or no information about the kinetic parameters.
Results: In this work, we combine a logic-based formalism, to describe all the possible regulatory structures for a given dynamic model of a pathway, with mixed-integer dynamic optimization (MIDO). This framework aims to simultaneously identify the regulatory structure (represented by binary parameters) and the real-valued parameters that are consistent with the available experimental data, resulting in a logic-based differential equation model. The alternative to this would be to perform real-valued parameter estimation for each possible model structure, which is not tractable for models of the size presented in this work. The performance of the method presented here is illustrated with several case studies: a synthetic pathway problem of signaling regulation, a two-component signal transduction pathway in bacterial homeostasis, and a signaling network in liver cancer cellsD.H., J.R.B. and J.S.R. acknowledge funding from the EU FP7 projects
‘NICHE’ (ITN Grant number 289384) and ‘BioPreDyn’ (KBBE grant number
289434). J.R.B. also acknowledges funding from the Spanish Ministerio de
Economía y Competitividad (and the FEDER) through the project
MultiScales (DPI2011-28112-C04-03).Peer reviewe
Revision of three species of Terebellides (Polychaeta: Trichobranchidae) described by C. Hessle in 1917 from the Southern Ocean
A revision of the taxonomic status of Terebellides antarcticus Hessle, 1917, Terebellides longicaudatus Hessle, 1917 and Terebellides minutus Hessle, 1917 was undertaken through the examination of the type material. Thus, T. longicaudatus is regarded as a valid species and redescribed and T. antarcticus and T. minutus are considered as junior synonyms of Terebellides kerguelensis McIntosh, 1818. Terebellides longicaudatus is characterized by the presence of large lateral lobes on chaetigers 1 to 5, 1 and 2 being the largest, first thoracic acicular neurochaetae gently bent, wide thoracic neuropodia fascicles with numerous uncini and the first notopodium greatly reduced. Comments on several body characters related to branchial and chaetal structure are also provided
Polychaeta of the ‘DIVA-Artabria I’ project (cruise 2002) in the continental shelf and upper slope off Galicia (NW Spain)
[Abstract] The present paper reports on the Polychaeta collected during the 2002 cruise of the ‘DIVA-Artabria I’ project in
the shelf and upper slope off Golfo Ártabro (Galicia, NW Spain). Eighteen samples were taken at 9 stations covering a
depth range from 150 to 1,140 m. Three different sampling gears were used: Agassiz trawl, Naturalist dredge and
Epibenthic sledge. A total of 5,598 specimens belonging to 43 polychaete families and 171 species were collected. The
polychaete assemblage differed between the shelf and the upper slope: the polychaete fauna from the shelf was composed
of infaunal taxa such as ampharetids, opheliids, paraonids and spionids and the upper slope was characterized by mobile
epibenthic taxa such as syllids, hesionids, and phyllodocids. The acrocirrid Macrochaeta polyonyx Eliason, 1962 is reported
for the first time for the Iberian Peninsula, and new morphological data are provided for the ampharetid Auchenoplax crinita
Ehlers, 1887 and the terebellid Euthelepus setubalensis McIntosh, 1885.[Résumé] Polychètes du projet ‘DIVA-Artabria I’ (campagne 2002) sur le talus et le plateau continental au large de la
Galice (Espagne). Ce travail a pour but d’étudier les Polychètes récoltés pendant la campagne 2002 du projet ‘DIVAArtabria
I’ sur le plateau continental et le talus du Golfo Ártabro (Galice, NW Espagne). Dix-huit échantillons ont été
prélevés à 9 stations à une profondeur de 150 à 1140 m. Trois appareils d’échantillonnage différents ont été utilisés: une
drague Agassiz, une drague de Naturaliste et un traîneau épibenthique. En tout, 5598 spécimens appartenant à 43 familles
et 171 espèces de polychètes ont été récoltés. L’assemblage de polychètes du plateau continental diffère de celui du talus :
la faune de polychètes du plateau est composée de taxa de l’endofaune tels les ampharétidés, les ophélidés, les paraonidés
et les spionidés, alors que le talus est caractérisé par des taxa épibenthiques mobiles tels les syllidés, les hésionidés et les
phyllodocidés. L’acrocirride Macrochaeta polyonyx Eliason, 1962 est cité pour la première fois dans la péninsule ibérique.
De nouvelles données morphologiques sont apportées sur l’ampharetidé Auchenoplax crinita Ehlers, 1887 et le térébellidé
Euthelepus setubalensis McIntosh, 1885.Ministerio de Educación y Cultura. DIVA Artabria II (CTM2004-00740/MAR)Ministerio de Educación y Cultura. Fauna Ibérica VIII (CGL2004-04680-C10-02/BOS)Ministerio de Educación y Cultura; CGL2007-66786-C08-02/BOSXunta de Galicia; PGIDT 01PXI20008P
Sphaerodoridae (Annelida: Polychaeta) from the DIVA-Artabria I project (2002 cruise) with description of a new species from the Ártabro Gulf (NW Iberian Peninsula)
Ministerio de Educación y Ciencia; PB95-0235Galicia. Consellería de Innovación, Industria e Comercio; PGIDT 01PXI20008PRMinisterio de Educación y Cultura; CTM2004-00740/MA
Two new species of Sphaerodoropsis Hartman & Fauchald, 1971 (Polychaeta: Sphaerodoridae) from Iceland (BIOICE programme)
Two new species of Sphaerodoropsis Hartman & Fauchald, 1971 (Polychaeta: Sphaerodoridae), collected during the BIOICE programme on sedimentary bottoms off Iceland, are described. Sphaerodoropsis gudmunduri sp. nov. is a shelf species (1000 m) and may be distinguished mostly by having up to 13 dorsal macrotubercles arranged in two transverse rows (6–7 macrotubercles, respectively) defining a zig-zag pattern (‘group 3’) and 7 dorsal papillae per chaetiger, up to 8–10 ventral papillae per chaetiger arranged in a non-random pattern and parapodia which bear one digitiform prechaetal lobe, one antero-lateral papilla and compound unidentate chaetae with blades with thin spinulation along their cutting edge. Both species show sexual dimorphism characterized by different arrangements of modified ventral cirri and/or special ventral structures in some mid-body chaetigers; a brief discussion about the presence of these structures on sphaerodorids and their possible importance on the systematics of the family is provided
Redescription of "Terebellides kerguelensis" stat. nov. (Polychaeta: Trichobranchidae) from Antarctic and subantarctic waters
During the Spanish Antarctic expeditions “Bentart” 1994, 1995 and 2003, a number of trichobranchid (Annelida: Polychaeta) specimens were collected and identified initially as Terebellides stroemii kerguelensis McIntosh, 1885, the only known species of the genus widely recognised as valid in Antarctic waters. In the framework of a worldwide revision of the genus Terebellides, a reconsideration of the taxonomic status of this subspecies of the boreal Terebellides stroemii Sars, 1835 is done through the examination of the syntypes of T. s. kerguelensis compared with recent descriptions of the nominal species from Norwegian waters and material from Icelandic waters. Thus, T. s. kerguelensis is regarded as a valid species, T. kerguelensis stat. nov., and redescribed designating a lectotype and paralectotypes. The species is mainly characterised by the presence of an anterior branchial extension (fifth lobe), lateral lappets in five anterior thoracic chaetigers, segmental organs in chaetigers 1, 4 and 5, and first thoracic acicular neurochaetae sharply bent with pointed tips. The biological role of the segmental organs, the presence and disposition of cilia in branchial lamellae and the finding of new structures located in dorsal part of thoracic notopodia are discussed.Consejo Interinstitucional de Ciencia y Tecnología; ANT93-0996Consejo Interinstitucional de Ciencia y Tecnología; ANT94-1161/EMinisterio de Ciencia y Tecnología; REN2001-1074/ANTMinisterio de Ciencia y Tecnología; CGL2004-0185
Redescription of "Sigambra tentaculata" and re-establishment of "S. parva" (Polychaeta, Pilargidae) based upon type material
[Abstract] The pilargid polychaetes Sigambra tentaculata and S. parva, to date considered synonyms, are redescribed from
the examination of type material and additional specimens from the East coast of the U.S.A., and the Atlantic and
Mediterranean coasts of Spain. The presence of tooth-like papillae on the proboscis of both species, which is revealed as a
character with high taxonomic relevance, is confirmed, as well as the possession of a dorsal row of peristomial papillae and
pectinate neurochaetae. Both species are morphologically very closely related but they show clear differences in the
arrangement and number of papillae and tooth-like papillae on the proboscis. S. parva is re-established as a valid species.[Résumé] Redescription de Sigambra tentaculata et revalidation de S. parva (Polychaeta, Pilargidae). Les polychètes pilargidés
Sigambra tentaculata et S. parva, jusqu’à présent considérés comme des espèces synonymes, sont redécrits à partir de
l’examen du matériel type et de spécimens additionnels provenant de la côte est des Etats-Unis et des côtes Atlantique et
Méditerranéenne d’Espagne. La présence de papilles en forme de dent sur la trompe chez les deux espèces, qui s’est révélée
comme un important caractère taxonomique, est confirmée, ainsi que la présence d’une rangée de papilles péristomiales
et de soies ventrales pectinées. Du point de vue morphologique, les deux espèces sont très proches, mais elles manifestent
des différences considérables en ce qui concerne l’arrangement et le nombre de papilles et de papilles en forme de dent de
la trompe. La validité de S. parva est rétablie.Argentina. Consejo Interinstitucional de Ciencia y Tecnología; PB959235Xunta de Galicia; XUGA30101A98Xunta de Galicia; PGIDT00PX130119P
Influencia del Subsistema de Aprovisionamiento de Recursos Humanos en el desempeño laboral de los trabajadores de la Empresa Aalfs Uno S.A Sebaco - Matagalpa, año 2015
El presente trabajo investigativo está enfocado al sistema de administración de recursos humanos y el subsistema de aprovisionamiento aplicado a las empresas de los departamentos de Matagalpa y Jinotega año 2015. Dichos procesos contribuyen a dotar de los recursos más idóneos a la institución para el logro de los objetivos organizacionales.
Del tema general se aborda el subsistema de aprovisionamiento de recursos humanos y su influencia en el desempeño laboral de los trabajadores de la empresa Aalfs uno S.A Sebaco Matagalpa, año 2015. El estudio da a conocer aspectos que podrán ser de gran utilidad para la empresa Aalfs uno, ya que podrá mejorar cada día más los procesos de trabajo como en la Administración de Recursos Humanos y demás áreas de la empresa.
Se conoció información que ayudó a determinar los factores, que están influyendo en el desempeño laboral de los empleados de Aalfs uno entre los cuales están: Población y fuerza laboral, descripción y análisis de puestos, aplicación de la técnica del incidente crítico y requisitos de personal así, como la función que ejerce la Administración de Recursos humanos en esta empresa.
El subsistema de aprovisionamiento de recursos humanos en el desempeño laboral aplicado a la empresa Aalfs uno cuenta con proceso de planeación, reclutamiento y selección para tener un buen personal laborando en la empresa, ya que se conocieron los procedimientos que se realizan, identificando la formalidad y el profesionalismo con que se lleva a cabo todo el proceso, además de eso se describieron los factores que influyen en el desempeño laboral de los empleados, siendo una preocupación para la empresa; por lo que implementa políticas de especialización, capacitación, planes de carrera, de la misma manera busca retener a los empleados en la empresa implementando planes de incentivos y trato especial a cada individuo; existe relación entre el aprovisionamiento ya que de la buena aplicación de todo el proceso resulta la buena eficiencia del individuo en el desempeño de su labor
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