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Search Results: 1 - 10 of 493185 matches for " Carlos V. P. de;Larica "
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Novel neutral iron(II) isocyanide maleonitrile dithiolate [Fe(S2C2(CN)2)(t-BuNC) 4] compound
Morigaki Milton K.,Silva Elias M. da,Melo Carlos V. P. de,Larica Carlos
Química Nova , 2004,
Abstract: FeBr2 reacts with the S2C2(CN)2(2-) ion (1:1 ratio) in the presence of an excess of t-BuNC in THF to give the mixed ligand [Fe(S2C2(CN)2)(t-BuNC) 4] compound. This neutral product with a formal oxidation state of two for the iron atom was characterized by conductivity measurements, and, i.r., M ssbauer, 13C and 1H n.m.r. spectroscopy. There is a Fe-C pi back-donation strengthened towards isocyanide ligands, according to the data of 13C, 1H n.m.r. and M ssbauer spectroscopy.
Novel neutral iron(II) isocyanide maleonitrile dithiolate [Fe(S2C2(CN)2)(t-BuNC) 4] compound
Morigaki, Milton K.;Silva, Elias M. da;Melo, Carlos V. P. de;Larica, Carlos;Biondo, Armando;Freitas, Jair C. C.;Dias, Gilson H. M.;Ribeiro, Holgadinei R.;
Química Nova , 2004, DOI: 10.1590/S0100-40422004000100016
Abstract: febr2 reacts with the s2c2(cn)22- ion (1:1 ratio) in the presence of an excess of t-bunc in thf to give the mixed ligand [fe(s2c2(cn)2)(t-bunc) 4] compound. this neutral product with a formal oxidation state of two for the iron atom was characterized by conductivity measurements, and, i.r., m?ssbauer, 13c and 1h n.m.r. spectroscopy. there is a fe-c p back-donation strengthened towards isocyanide ligands, according to the data of 13c, 1h n.m.r. and m?ssbauer spectroscopy.
Finite One-Dimensional Photonic Crystal with Gaussian Modulation: Transmission and Escape  [PDF]
María de la Luz Silba-Vélez, David-Armando Contreras-Solorio, Rolando Pérez-álvarez, Carlos Iván Cabrera
Optics and Photonics Journal (OPJ) , 2017, DOI: 10.4236/opj.2017.710017
Abstract: This paper studied the transmission coefficient and escape frequencies in a system of planar dielectric layers where the refractive index changes from one layer to another through a Gaussian function. The wave equation with normal incidence is analyzed. For the calculations, the transfer matrix formalism is used. In a previous work, the transmission and escape problem for Gaussian electronic superlattices is investigated. Now it studied the electromagnetic modes for a system formed by layers where the refractive index of the structure is modulated by a Gaussian function. The system presents transparency bands of transmission and gaps without transmission. The escape frequencies \"\" are situated near these transparency bands but they do not coincide with them. is the frequency (mode) and Γ describes the width of the states. For these systems, the escape states are very wide. A non Gaussian system presents resonance peaks in the transmission and the escape states are narrow. The formation of transparency bands in the transmission for a Gaussian system is attributed to the widening of the escape states.
Rol de los murciélagos insectívoros en la transmisión de la rabia en Chile
Archivos de medicina veterinaria , 1999, DOI: 10.4067/S0301-732X1999000200002
Abstract: the importance of wild animals in the epidemiology of rabies in chilewas not recognized until 1985. since then the epidemiology of rabies hasbeen characterized by the presence of an endemic cycle in the species ofthe order chiroptera. in 1996, after 24 years without human rabies cases,a child died of the disease. the victim was infected with an antigenicvariant 4 (agv4) virus whose reservoir is the non-hematophagous bats tadaridabrasiliensis. this event emphatized the need for a better characterizationof rabies selvatic cycles, their geographical distribution, and the riskfactors that influence the virus transmission to humans and domestic animalsin the country. from a total of 250 isolates obtained between 1977 and 1997, 119 werereactived. these samples were antigenically characterized by the indirectinmunofluorescence technique using a panel of 8 monoclonal antibodies directagainst epitopes of the viral nucleoprotein produced by the centers ofdisease control and prevention, atlanta, georgia, usa. the analysis showedthat all the viruses obtained from non-hematophagous bats were agv4 sevenout of 10 canine isolates were agv4. the other 3 canine viruses were agv1,whose reservoir is the dog. of the 3 bovine isolates, 2 was agv1 and 1agv4. three feline and one porcine viruses was caracterized as agv4. itwas determined that a bovine rabies case reported in 1977 and all the virusesisolated from domestic animals since 1990 were agv4. these results allowed to conclude that, in chile, the non-hematophagousbats tadarida brasiliensis was a rabies selvatic reservoir before1985, and since then it has been the only wild reservoir know responsiblefor rabies sporadic cases in human and domestic animals
Análise de sensibilidade dos métodos de estimativa da evapotranspira??o de referência e raz?o de Bowen em cultura da cana-de-a?úcar
Silva, Bruce K. N;Silva, Vicente de P. R. da;Azevedo, Pedro V. de;Farias, Carlos H. de A;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2011, DOI: 10.1590/S1415-43662011001000008
Abstract: the sensitivity analysis technique of models was applied to the data obtained from field experiment carried out during 2009 at distillery miriri, capim, pb. this technique was applied to the reference evapotranspiration (eto) by penman-monteith (fao/56) and the sugarcane evapotranspiration (etc) by energy balance equation based on bowen ratio. the sensitivity analysis and errors were applied to the bowen ratio method in measurement intervals of 15, 30, 60 and 120 min; however penman-monteith approach was applied on daily basis throughout the 2009 year. results showed that the net radiation is the most sensitive variable in the energy equation balance and soil heat flux offers the lowest contribution. on the other hand, the relative errors for all variables in energy balance equation increase significantly with increase in sampling interval. the most sensitive variable in reference evapotranspiration by penmam-monteith method is net radiation, followed by relative humidity, wind speed at 2 m and air temperature.
Visualiza??o in vitro da coloniza??o de raízes por rizobactérias
Queiroz, Brigida P. V. de;Aguilar-Vildoso, Carlos I.;Melo, Itamar S.;
Summa Phytopathologica , 2006, DOI: 10.1590/S0100-54052006000100017
Abstract: for in vitro colonization to be quickly verified, substrate transparency is important. with this objective, a simple method was modified and the visualization of rhizobacteria in the roots was correlated to their colonization via scanning electron microscopy (sem). seeds of citrus limonia osbeck were inoculated and monitored in glass tubes with different substrates (agar-agar, agar noble and phytagel). seven rhizobacteria strains were evaluated, and an isolate of escherichia coli dh5a was used as the negative control. phytagel allowed a clearer visualization of the colonization along the roots by the bacteria and a higher sensibility for the confirmation of the rhizobacteria. roots that presented turbidity around the agar exhibited an efficient surface colonization when observed in high magnification. this method showed to be a very good tool to study the root colonization via sem.
Presence of the cytolytic protein enterolobin in different developmental stages of Enterolobium contortisiliquum seeds
Lima, Consuelo M. R. de;Zanotta, Pedro J. P.;Ricart, Carlos A. O.;Sousa, Marcelo V. de;
Brazilian Journal of Plant Physiology , 2007, DOI: 10.1590/S1677-04202007000200008
Abstract: enterolobin is a 52.9 kda, cytolytic, inflammatory and insecticidal protein present in enterolobium contortisiliquum (vell.) morong, a brazilian large-sized tree. this protein was previously described to occur in different forms of association (monomeric and oligomeric forms). in the current work, we investigated the presence of enterolobin forms of association and hemolytic activity in maturing, germinating and germinated seeds. immunoblotting analysis revealed the presence of the monomeric form of enterolobin in all phases under study, whereas the dimer was detected in developing seeds in the second half of the maturation period, during germination and in the early post-germination phase. the trimeric form of enterolobin appeared one week after the dimer and could be detected up to half of the average germination time of the e. contortisiliquum seeds. the highest hemolytic titers due to enterolobin activity were found in mature and germinating seeds. apparently, there was no modification in molecular mass of the enterolobin monomer during seed maturation and germination, suggesting the absence of a precursor form. the results also show that enterolobin was not utilized in germination and initial post-germination phases, which are critical in development and seedling establishment. enterolobin availability could enable it to perform an important physiological role, including plant defense.
Características de frutos de piment?o cultivado em ambiente protegido sob doses de nitrogênio via fertirriga??o
Araújo, Jucilene S.;Andrade, Alberício P. de;Ramalho, Cícera I.;Azevedo, Carlos A. V. de;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2009, DOI: 10.1590/S1415-43662009000200007
Abstract: this study was conducted at the center of agricultural sciences-ufpb, from february to june 2004, aiming to evaluate the effect of applied doses of nitrogen via fertigation, on the characteristics of bell pepper fruits cultivated in greenhouse. the adopted experimental design was in randomized blocks, with five treatments (0, 100, 200, 300 and 400 kg ha-1) and 4 repetitions. length, diameter and mean weight of fruits and number of fruits per plant were evaluated. significant effects of the doses of nitrogen were verified on the diameter, mean weight and total, commercial and noncommercial number of fruits of bell pepper. the length of fruits of the bell pepper was not influenced by the doses of nitrogen; however, the obtained values are within the standard average for the studied variety. the maximum dose of nitrogen (400 kg ha-1) promoted an increment of 7.3 (increase of 133%) fruits considered of commercial quality in relation to the control (0 kg ha-1). the fruits recognized as noncommercial showed an excellent aspect, in their appearance and hygiene quality, with just their length and diameter below the estabilished standards.
Cultivo do piment?o em condi??es protegidas sob diferentes doses de nitrogênio via fertirriga??o
Araújo, Jucilene S.;Andrade, Alberício P. de;Ramalho, Cícera I.;Azevedo, Carlos A. V. de;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2009, DOI: 10.1590/S1415-43662009000500008
Abstract: aiming to evaluate the effect of doses of nitrogen applied via fertirrigation on the yield of bell pepper cultivated in greenhouse, this work was conducted at the center of agrarian sciences - ufpb. the experiment consisted of five treatments (0, 100, 200, 300 and 400 kg ha-1 of n) and 4 repetitions. total, commercial and non-commercial fruit yields were evaluated, and the relationship between the leaf area and the leaf area index with the yields were determined. the doses of nitrogen influenced linearly and positively the total (commercial plus non-commercial fruits) and for the commercial yield of fruits, and for non-commercial fruits of the bell pepper a quadratic function was observed. the thermal accumulation of the bell pepper to reach the phase of larger yield was of 1.668 oc, and to complete its whole phenologic cycle, 2.155 gda were necessary. the leaf area and the leaf area index affected the total yield of fruits of bell pepper, in a linear and positive way. the leaf area index showed itself to be satisfactory for the conditions of this experiment, demonstrating that the density of the plants used was adequate.
Material envoltório na drenagem subterranea
Almeida, Florício P. de;Lima, Vera L. A. de;Azevedo, Carlos A. V. de;Dantas Neto, José;Pordeus, Roberto V.;
Engenharia Agrícola , 2005, DOI: 10.1590/S0100-69162005000300012
Abstract: in soils of low structural stability, transport by water of soil particles into drainage tube can contribute to collapse of drainage systems, which must be avoided with the adequate use of envelope, considering the drainage importance for a sustainable agricultural production. thus, this research was accomplished with the purpose of studying the behavior of three envelope materials, being two of them widely used, the bidim op-20 and the zero crush, and other composed of foam with 5.0 mm of thickness, which is a non-conventional material. the drainage tubes used were the drenoflex and the kananet, with nominal diameter of 65 and 75 mm, respectively. the envelopes performance was evaluated by the entrance resistance and discharge, parameters traditionally recommended for this kind of analysis. it was verified that evaluated envelopes presented satisfactory hydraulic performance, being the zero crush superior envelope, followed by the foam material. then, it is concluded that the foam can be used as an alternative envelope material in drainage, presenting inclusively, a superior hydraulic performance to bidim op-20 envelope.
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