6,837 research outputs found

    Complex network view of evolving manifolds

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    We study complex networks formed by triangulations and higher-dimensional simplicial complexes representing closed evolving manifolds. In particular, for triangulations, the set of possible transformations of these networks is restricted by the condition that at each step, all the faces must be triangles. Stochastic application of these operations leads to random networks with different architectures. We perform extensive numerical simulations and explore the geometries of growing and equilibrium complex networks generated by these transformations and their local structural properties. This characterization includes the Hausdorff and spectral dimensions of the resulting networks, their degree distributions, and various structural correlations. Our results reveal a rich zoo of architectures and geometries of these networks, some of which appear to be small worlds while others are finite-dimensional with Hausdorff dimension equal or higher than the original dimensionality of their simplices. The range of spectral dimensions of the evolving triangulations turns out to be from about 1.4 to infinity. Our models include simplicial complexes representing manifolds with evolving topologies, for example, an h-holed torus with a progressively growing number of holes. This evolving graph demonstrates features of a small-world network and has a particularly heavy-tailed degree distribution.Comment: 14 pages, 15 figure

    Ontogenia larval comparativa de duas esp?cies (Characiformes e Siluriformes) end?micas do rio S?o Francisco

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    Objetivou-se com este trabalho comparar histologicamente o desenvolvimento ontogen?tico de duas esp?cies de peixes end?micos da bacia do rio S?o Francisco, Prochilodus argenteus (curimat?-pacu) e Lophiosilurus alexandri (pacam?). As coletas para as an?lises histol?gicas foram realizadas a cada 24 horas a partir do momento da eclos?o at? o 14? dia p?s-eclos?o (DPE) para a observa??o do desenvolvimento larval e at? o 39? DPE para a observa??o do desenvolvimento gonadal. As larvas foram fixadas inteiras em solu??o de Bouin e as l?minas histol?gicas foram coradas pelo m?todo de Hematoxilina-Eosina. Larvas de pacam? exibiram um tamanho corporal maior em rela??o ?s larvas de curimat?-pacu desde a eclos?o. Larvas de pacam? apresentaram a abertura da boca e in?cio da pigmenta??o dos olhos no momento da eclos?o, enquanto que nas larvas de curimat?-pacu, esses eventos foram observados no 1? DPE. No curimat?-pacu a visualiza??o e a insufla??o da bexiga natat?ria ocorreram no 1? e 3? DPE, respectivamente, sendo esses eventos mais tardios no pacam?, com visualiza??o no 2? e insufla??o no 8? DPE. Os gr?nulos de vitelo foram absorvidos no 4? DPE pelo curimat?-pacu e no 10? DPE pelo pacam?. No 7? DPE, o tubo digest?rio do pacam? apresentou-se mais diferenciado em rela??o ao curimat?-pacu. O sistema digest?rio de ambas as esp?cies ao 14? DPE demonstraram caracter?sticas relacionadas aos seus respectivos h?bitos alimentares, com est?mago amplo e intestino curto no pacam?, t?picos de h?bito carn?voro; est?mago com fun??o mec?nica e intestino longo no curimat?-pacu, t?picos de h?bito detrit?voro. O tecido epitelial de revestimento, formado por uma ?nica camada de c?lulas nas larvas rec?m-eclodidas (0 DPE), apresentou diferencia??o ao longo dos dias, exibindo presen?a de escamas no curimat?-pacu e numerosas c?lulas ?club? na regi?o epitelial intermedi?ria do pacam?, em avalia??es realizadas ao 39? DPE. Analisando os indiv?duos com 39 DPE, verificou-se a presen?a de g?nadas indiferenciadas com c?lulas som?ticas e c?lulas germinativas primordiais que foram observadas realizando migra??o no sentido caudo-cranial desde o 1? DPE em ambas as esp?cies. P?de-se concluir que as altera??es anat?micas observadas durante a ontogenia de larvas P. argenteus e L. alexandri est?o diretamente relacionadas ao h?bito alimentar e ao comportamento inerente ? cada esp?cie, sendo uma detrit?vora que nada ativamente na coluna d??gua, e outra carn?vora que habita regi?es de fundo, respectivamente. Aos 39 dias p?s-eclos?o, em ambas as esp?cies n?o foram observados ind?cios histol?gicos de diferencia??o sexual.Banco do Nordeste do Brasil (BNB)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.The objective of this work was to compare histologically the ontogenetic development of two endemic species of fish from the S?o Francisco river basin, Prochilodus argenteus (curimat?-pacu) and Lophiosilurus alexandri (pacam?). The samples for the histological analyzes were performed every 24 hours since the moment of hatching until the 14th day post-hatching (DPH) for observation of the larval development and until the 39th DPH for the observation of gonadal development. The whole larvae were fixed in Bouin's solution and the histological slides were stained by the Hematoxylin-Eosin method. Pacam? larvae exhibited a larger body size relative than the curimat?-pacu larvae since hatching. Pacam? larvae presented the mouth opening and pigmentation of eyes beginning at the time of hatching, whereas in curimat?-pacu larvae, these events were observed in the 1st DPH. The visualization and the inflation of the swim bladder in the curimat?-pacu, occurred in the 1st and 3rd DPH, respectively, being these events in the pacam? later, with visualization in the 2nd and insufflation in the 8th DPH. The yolk granules were absorbed in the 4th DPH by the curimat?-pacu and in the 10th DPE by the pacam?. In the 7th DPH, the pacam??s digestive tube was more differentiated than curimat?-pacu. The digestive system of both species at the 14th DPH has features of it eating habits the pacam?, with a broad stomach and a short intestine in the pacam?, typical of a carnivorous habit; stomach with a mechanical function and a long intestine in curimat?-pacu, typical of detritivorous habit. The epithelial lining tissue, formed by a single layer of cells in the newly hatched larvae (0 DPH), showed a differentiation throughout the days, exhibiting scales in curimat?-pacu and numerous club cells in the middle epithelial region of the pacam?, at evaluations carried at the 39th DPH. Analyzing the individuals with 39 DPH, the presence of undifferentiated gonads with somatic cells and primordial germinative cells were observed, which has a caudate-cranial migration since 1st DPH in both species. It was concluded that the anatomical alterations of the ontogeny of P. argenteus and L. alexandri larvae are directly associated to the feeding habit and the inherent behavior of each species, being these detritivorous that nothing actively in the column of water and carnivorous that inhabits bottom regions, respcectively. At the 39 day post-hatching, both species hasn't evidenced of sexual differentiation

    MODAL SOSIAL DAN RESILIENSI DALAM MENGHADAPI PANDEMI COVID-19: STUDI KASUS PT.VENUS PRIMA SENTOSA

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    This study aims to identify a family firm’s resources to survive during the crisis, especially the covid-19 pandemic crisis. This study undertakes a case study in PT Venus Prima Sentosa, owner of Roti Unyil Venus, a specialty culinary gift from Bogor, which has been in the business for 30 years. The study uses a qualitative approach with an in-depth interview and desk study research as data collection methods. Data is analyzed using a resource-based view and social capital with relational, cognitive, and structural dimensions. The results identify that internal and external social capital has contributed to the company’s resiliency when facing with COVID-19 pandemic crisis. Internal social capital consists of trust and respect between family members and employees. Meanwhile, the external social capital consists of suppliers’ loyalty, cooperation with related businesses, and compliance with government rules during the COVID-19 pandemic. Hopefully, these results can help other business owners strengthen their social capital to gain competitive advantage and business resilience, especially in the food industry.Penelitian ini bertujuan untuk megidentifikasi sumber daya yang dimiliki sebuah perusahaan keluarga agar dapat bertahan di masa krisis, terutama krisis akibat pandemi covid-19. Penelitian ini melakukan studi kasus pada PT Venus Prima Sentosa, pemilik usaha Roti Unyil Venus, makanan oleh-oleh khas Kota Bogor yang telah beroperasi selama 30 tahun. Metode penelitian kualitatif dengan teknik pengumpulan data melalui wawancara mendalam dan pengolahan data sekunder. Analisis data menggunakan pendekatan resources-based view dan modal sosial dengan dimensi relasional, kognitif dan struktural. Hasil penelitian menemukan modal sosial internal dan modal sosial eksternal berperan dalam keberhasilan perusahaan melalui krisis akibat pandemi covid-19. Modal sosial internal terdiri dari relasi kepercayaan dan saling hormat antar anggota keluarga dan karyawan. Modal sosial eksternal bersumber pada loyalitas pemasok, kerjasama dengan usaha sejenis, serta kepatuhan pada peraturan pemerintah terutama di masa krisis pandemic covid-19. Penelitian ini dapat mendorong pelaku usaha, khususnya di industri makanan, untuk memperkuat modal sosial sebagai salah satu sumber daya dalam membentuk keunggulan bersaing dan membentuk resiliensi usaha

    Different cell disruption methods for astaxanthin recovery by Phaffia rhodozyma

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    Astaxanthin (3,3'-dihydroxy-b,b'-carotene-4,4'-dione) is carotenoid of high market value whose demand has increased in such fields as aquaculture, pharmaceutical supplements and natural coloring. Cell disruption is the first step for isolating intracellular materials and it depends on the cell wall permeability. In order to maximize the  recovery of astaxanthin from Phaffia rhodozyma NRRL-Y17268, drying and freeze pretreatments were tested by different cell disruption methods: abrasion with celite, glass pearls in vortex agitator, ultrasonic waves, sodium  carbonate (Na2CO3) and dimethyl sulfoxide (DMSO). The method with Na2CO3 was not effective; meanwhile, the agitator with glass pearls, the abrasion with celite and the ultrasonic waves were found as promising for future  studies. As a result, the DMSO in freeze-dried biomass with 4 process cycles and biomass/DMSO relation of 0.025 g/ml was found to be the most efficient for analytical determination, increasing about up to 25 times the astaxanthin recovery.Key words: Carotenoids, yeast, chemical disruption, dimethyl sulfoxide

    Polyvalent horse F(Ab`)2 snake antivenom: Development of process to produce polyvalent horse F(Ab`)2 antibodies anti-african snake venom

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    A method to obtain polyvalent anti-Bitis and polyvalent-anti-Naja antibodies was developed by immunizing horses with B. arietans, B. nasicornis, B. rhinoceros, N. melanoleuca and N. mossambicacrude venoms. Antibody production was followed by the ELISA method during the immunization procedure. Once the desired anti-venom antibody titers were attained, horses were bled and the immunoglobulins were separated from the sera by (NH4)2SO4 precipitation, cleaved with pepsin and filtered through a 30 kDa ultrafiltration membrane. F(ab´)2 fragments were further purified by Q-Fast Flow chromatography, concentrated by molecular ultrafiltration and sterilized by filtration through 0.22 m membranes. The resulting F(ab´)2 preparations were rich in intact L and in pieces of H IgG(T) chains, as demonstrated by electrophoresis and Western blot and exhibited high antibody titers, as assayed by the ELISA method. In addition, the preparations possess a significant capacity to neutralize the lethality of venoms, as estimated by ED50 determination in mouse assay and are free of toxic substances, pyrogen and bacterial or fungal contaminations

    Artigos religiosos: influ?ncias na decis?o de compra dos clientes na livraria Nossa Senhora de F?tima da cidade de Passa e Fica ? RN

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    TCC - Artigos religiosos: influ?ncias na decis?o de compra dos clientes na livraria Nossa Senhora de F?tima da cidade de Passa e Fica ? RN / Ol?via Kaion?ra Dam?sio da SilvaEm meio ?s mudan?as mercadol?gicas, v?rios segmentos religiosos est?o surgindo no mercado, inovando e buscando cada vez alcan?ar novos p?blicos. Um deste segmento, que tem crescido e conquistado seu espa?o ? o com?rcio de artigos religiosos, impulsionado pelas redes cat?licas ou crist?s de televis?o, pelas pr?ticas religiosas que tem forte influ?ncia sobre o comportamento dos indiv?duos. O presente estudo buscou identificar as raz?es que influenciam o comportamento dos consumidores de artigos religiosos cat?licos bem como o perfil do consumidor e os aspectos na decis?o de compra. A pesquisa foi elaborada em uma livraria local atrav?s de entrevista semiestruturada com uma empreendedora do munic?pio de Passa e Fica RN, com m?todo quali-quantitativo e um estudo de caso, realizado com os clientes da livraria atrav?s de um question?rio on-line elaborado pelo Google forms, aplicados aos clientes por meio de um link enviado pelo aplicativo WhatsApp. A pesquisa gerou a seguinte conclus?o: seguimento de produtos religiosos cat?licos embora ligado ? religi?o move a economia como qualquer outro produto, pois as raz?es na decis?o de compra seguem o padr?o de consumo ligado a fatores psicol?gicos, socioculturais, situacionais e grau de envolvimento do consumidor

    Drug Release from Microspheres and Nanospheres of Poly(lactide-co-glycolide) without Sphere Separation from the Release Medium

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A new technique using diffuse reflectance spectroscopy was developed that enables the monitoring of encapsulated drug release without particle separation from the assayed medium. Studies of chloro(5,10,15,20-tetraphenylporphyrinato)indium(III) (InTPP) release from microspheres and nanospheres of poly(lactide-co-glycolide) (PLGA) were performed using this new technique. The release of InTPP was biphasic, with an initial fast release followed by a second slower release. Mathematical models applied to the release profiles showed that the release of InTPP from the nanospheres was controlled by diffusion, which is to be expected for a substance homogeneously dispersed within the spheres. However, due to the large size distribution of the microspheres loaded with InTPP, the release profiles were irregular, hampering an adequate fit to mathematical models. Confocal analysis of microparticles showed that the InTPP appeared to be homogenously distributed within the microspheres and no preferential distribution of InTPP towards the interior or towards the surface of the spheres was observed.212214225Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Estadual de CampinasFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Pollen morphology in tribe Dicomeae Panero and Funk (Asteraceae)

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    To better understand the taxonomy and phylogeny of the Dicomeae (Asteraceae) the pollen morphology of seven genera including 15 species of that tribe and six genera with seven species belonging to five related tribes was studied by use of light and scanning electron microscopy. The quantitative data were analysed by use of principal-components analysis (PCA). The exine ultrastructure of Erythrocephalum longifolium and Pleiotaxis rugosa was also studied by use of transmission electron microscopy. Three pollen types were distinguishable from the apertural, columellar, and spinular morphology and inter-spinular sculpture. A dichotomous key to these pollen types is proposed. The existence of the Dicomeae as an independent tribe and its subdivision in two subtribes (Dicominae and Pleiotaxinae) are supported by this study, which also suggests the Oldenburgieae and the Tarchonantheae are the closest tribes to Dicomeae
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