Evaluation of mitochondrial activity in spermatozoids after collecting and posthawing in Boer and Alpine goats in autumn and spring

Caprine spermatozoa undergo glycolisis and mitocondrial respiration to keep the necessary energy balance to their transportation and other cellular functions. An objective test to evaluate quantitatively and qualitatively mitochondrial activity in caprine spermatozoa was applied in the analysis of semen samples of 9 bucks from Boer (n=5) and Alpine (n=4) breeds. Samples were collected and frozen in TRIS medium in two different year seasons. Semen collection was performed using artificial vagina to obtain 135 ejaculates, which were used to post-collection and post-frozen extended in sildes. To determine mitochondrial activity, a citochemical procedure developed and validated for HRUDKA (1987) was used. The technique is based on the enzymatic 3,3-diaminobenzidine (DAB) oxidation, where the reagent is polymerized and attached to the mitochondrial membrane throughout the spermatic intermediary piece. A medium level of citochemical activity (IAC) was determined as being 74,37%, 74,37% during Autumn and 77% e 77,75% during Spring for Boer and Alpine breeds, respectively. For post-collection IAC levels were 85,62% and 85,93 and for post-frozen 66% and 67,25% for Boer and Alpine breeds, respectively. ANOVA test was used to evaluate breed, post-collection, post-frozen, IAC rates and year season parameters. Differences were not noticed for breed, IAC rates and year season. Nonetheless, there was a significant effect among samples for post-collection and post-frozen analysis (POs espermatozóides caprinos realizam a respiração mitocondrial, mantendo um balanço energético necessário para o transporte e as demais funções celulares. Um teste objetivo de avaliação quantitativa e qualitativa da atividade mitocondrial em espermatozóides caprinos foi aplicado no sêmen de nove reprodutores das raças Boer (n=5) e Alpina (n=4) colhidos e congelados em diluidor TRIS em duas estações. A colheita do sêmen foi realizada com auxílio da vagina artificial, totalizando 135 ejaculados e foram confeccionados esfregaços com sêmen pós-colheita e pós-descongelação. Para a determinação da atividade mitocondrial foi utilizado o procedimento citoquímico desenvolvido e validado por HRUDKA (1987). Esta técnica é baseada na oxidação da 3,3-diaminobenzidine (DAB) pela enzima em reação em cadeia, onde o reagente é polimerizado e depositado na bainha mitocondrial ao longo da peça intermediária dos espermatozóides. Foi determinado um índice médio de atividade citoquímica (IAC) de 74,37%, 74,37% no outono, 77% e 77,75% na primavera. E 85,62% e 85,93 no pós-colheita, 66% e 67,25% pós-descongelação para as raças Boer e Alpina, respectivamente. As variáveis raças, pós-colheita e pós-descongelação, classes (IAC), e estação foram estudadas por meio de ANOVA. Não foram observadas diferenças estatísticas para raças, classes, bem como para as estações. Entretanto, efeito significativo entre as amostras pós-colheita e pós-descongelação (

Reproductive phenology of Dipteryx odorata (Aubl.) Willd (Fabaceae) in two forest areas in the Central Amazon

Long term phenological studies in tropical forests are scarce. A phenological study of Dipteryx odorata was carried out from 1974 to 2000 in two areas of Amazon Forest: Reserva Florestal Ducke (RFD) and Estação Experimental de Silvicultura Tropical (EEST). The objective was to compare the phenological patterns between the two areas, to verify the regularity of flowering and fruiting over a period of 27 years, and to verify the influence of climatic factors in these events. Five trees were marked in the RFD and five in the EEST; and were observed monthly for the presence of flowers, unripe and ripe fruits. The flowering and unripe fruiting presented an irregular pattern in both areas, and also varied with regard to duration and period of occurrence between years and seasons. Nevertheless, they presented similar frequency of occurrence during the 27 years of observation. On the other hand, the production of ripe fruits presented a different pattern, with three year intervals without ripe fruits in the RFD, and seven year intervals in the EEST. We concluded that the frequency of flowering and unripe fruiting was annual, and the frequency of occurrence of ripe fruiting was supra-annual, with an irregular pattern, and a duration from intermediate to extended. We also observed the occurrence of one to three year intervals between flowering and unripe fruiting episodes, and one to seven year intervals between episodes with ripe fruiting. The influence of climatic factors in the patterns observed was not clear. We suggest the rational use of natural products extracted from Dipteryx odorata, the "cumaru", especially the fruits, and the development of more long term studies, fundamental for understanding the reproductive phenological patterns as well as the resource offering patterns in tropical forests.Estudos fenológicos de longa duração em florestas tropicais são raros. Foi realizado o acompanhamento fenológico de Dipteryx odorata, no período de 1974 à 2000, em duas áreas de floresta amazônicaa Reserva Florestal Ducke (RFD) e Estação Experimental de Silvicultura Tropical (EEST). O objetivo foi observar os padrões fenológicos nas duas áreas, verificar a regularidade da floração e frutificação num período de 27 anos e a influência dos fatores climáticos nestes eventos. Foram marcados cinco indivíduos na RFD e cinco na EEST e observados quanto à produção de flores, frutos imaturos e maduros. A floração e a produção de frutos imaturos apresentaram padrão irregular nas duas áreas observadas, variando quanto a época de ocorrência e a duração entre anos e estações, mas apresentaram freqüência de ocorrência similar nos 27 anos observados. Para a fenofase frutos maduros este padrão foi diferente, com intervalos de até três anos sem ocorrência de frutos maduros, na RFD e de sete anos na EEST. Conclui-se que a freqüência de ocorrência das fenofases de floração e frutos imaturos foi anual e a de frutos maduros supra-anual, todas com padrão irregular e duração de intermediária a prolongada. Ocorreu variação de um a três anos entre episódios de floração e frutos imaturos e de um a sete anos entre episódios de frutos maduros, não ficando evidente, nesta análise, a influência dos fatores climáticos nos padrões observados. Sugere-se o uso racional dos produtos derivados de Dipteryx odorata, o cumaru, especialmente quanto à exploração de seus frutos e o desenvolvimento de mais estudos de longa duração, fundamentais para entender os padrões fenológicos reprodutivos e de oferta de recursos em florestas tropicais

The Max-plus Algebra And The Network Calculus

Discrete Event Dynamic Systems (DEDS) are systems whose state transitions are triggered by events that occur at discrete instants of time. The communication networks are examples of this kind of systems. The mathematical constraints of some DEDS can be described more adequately using the Max-Plus algebra. Previous works show that the problem of determining performance bounds for communication networks is simplified if modeled using this algebra. The compilation of existing rules and results on this field is called Network Calculus. The goal of this article is to improve a systematic use of the Max-Plus algebra in the formulation and derivation of results on Network Calculus. To illustrate the introduced methodology, we analyze a window flow controller, a system that controls the traffic admitted by a network in order to limit its backlog in a specified manner. © 2006 IEEE.433438Cassandras, C.G., Lafortune, S., (1999) Introduction to Discrete Event Systems, , Kluwer Academic PublishersChang, C.-S., On deterministic traffic regulation and service guarantees: A systematic approach by filtering (1998) IEEE Transactions on Information Theory, 44 (3), pp. 1097-1110. , MayChang, C.-S., Cruz, R.L., Boudec, J.-Y.L., Thiran, P., A Min,+ system theory for constrained traffic regulation and dynamic service guarantees (2002) IEEE/ACM Transactions on Networking, 10 (6), pp. 805-817. , DecemberLe Boudec, J.-Y., Application of Network Calculus to guaranteed service networks (1998) IEEE Transactions on Information Theory, 44 (3), pp. 1087-1096. , MayLe Boudec, J.-Y., Thiran, P., Network Calculus- A Theory of Deterministic Queuing Systems for the Internet (2003) Online Version of the Book Springer Verlag - LNCS 2050, , http: //ica1www.epflch/PSfiles/ NetCal.htm, June 25Le Boudec, J.-Y., (1996) Network Calculus made easy, , DI-EPFL, Lausanne, Switzerland, Tech. Rep. 96/218, CH-1015, DecemberJ.-Y. Le Boudec, P. Thiran, and S. Giordano, A short tutorial on Network Calculus I: Fundamental bounds in communication networks, in ISCAS 2000 - IEEE International Symposium on Circuits and Systems, Geneva, Switzerland, May 28-31 2000, pp. IV-93-IV-96_, A short tutorial on Network Calculus II: Min-plus system theory applied to communications networks, in ISCAS 2000 - IEEE International Symposium on Circuits and Systems, Geneva, Switzerland, May 28-31 2000, pp. IV-365Agrawal, R., Rajan, R., (1996) Performance bounds for guaranteed and adaptive services, , IBM, Tech. Rep. RC 20649, DecemberCruz, R.L., Quality of Service guarantees in virtual circuit switched networks (1995) IEEE Journal on Selected Areas in Communications, 13 (6), pp. 1048-1056. , AugustBaccelli, F., Cohen, G., Olsder, G.J., Quadrat, J.-P., (1992) Synchronization and Linearity: An Algebra for Discrete Event Systems, , England: John Wiley & Son

Max-plus: A Network Algebra

Networks can support Quality of Service (QoS) architectures for a wide variety of applications. The Network Calculus (NC) appeared as a set of rules and results for computing bounds for QoS parameters. The goal of this paper is to improve the systematic use of the Max-Plus algebra in the formulation and derivation of NC results. To illustrate the presented methodology, we analyze the problem of optimizing the playback delay and the buffer size of an optimal video decoder with some look-ahead. © 2006 Springer-Verlag Berlin/Heidelberg.341375382Baccelli, F., Cohen, G., Olsder, G.J., Quadrat, J.-P., (1992) Synchronization and Linearity: An Algebra for Discrete Event Systems, , John Wiley & Sons, EnglandChang, C.-S., On deterministic traffic regulation and service guarantees: A systematic approach by filtering (1998) IEEE Transactions on Information Theory, 44 (3), pp. 1097-1110. , MayChang, C.-S., Cruz, R.L., Le Boudec, J.-Y., Thiran, P., A Min,+ system theory for constrained traffic regulation and dynamic service guarantees (2002) IEEE/ACM Trans. on Networking, 10 (6), pp. 805-817. , DecemberCruz, R.L., Quality of Service guarantees in virtual circuit switched networks (1995) IEEE Journal on Selected Areas in Communications, 13 (6), pp. 1048-1056. , AugustLe Boudec, J.-Y., Network Calculus made easy (1996) Technical Report, 96 (218). , CH-1015, DI-EPFL, Lausanne, Switzerland, DecemberLe Boudec, J.-Y., Application of Network Calculus to guaranteed service networks (1998) IEEE Trans. on Information Theory, 44 (3), pp. 1087-1096. , MayLe Boudec, J.-Y., Thiran, P., (2003) Network Calculus- A Theory of Deterministic Queuing Systems for the Internet, , http://ica1www.epfl.ch/PS_files/NetCal.htm, Springer Verlag - LNCS 2050, June 25Le Boudec, J.-Y., Thiran, P., Giordano, S., A short tutorial on Network Calculus I: Fundamental bounds in communication networks (2000) IS-CAS 2000 - IEEE Int. Symp. on Circuits and Systems, pp. IV93-IV96. , Geneva, Switzerland, May 28-31Le Boudec, J.-Y., Thiran, P., Giordano, S., A short tutorial on Network Calculus II: Min-plus system theory applied to communications networks (2000) ISCAS 2000 - IEEE Int. Symp. on Circuits and Systems, pp. IV-365. , Geneva, Switzerland, May 28-3

Accuracy of phenotypic methicillin susceptibility methods in the detection of Staphylococcus aureus isolates carrying different SCCmec types

A total of 138 isolates, 118 methicillin-resistant Staphylococcus aureus (MRSA) isolates (staphylococcal cassette chromosome type II, 20 isolates, type III, 39 isolates and type IV, 59 isolates) and 20 methicillin-sensitive S. aureus isolates were evaluated by phenotypic methods: cefoxitin and oxacillin disk diffusion (DD), agar dilution (AD), latex agglutination (LA), oxacillin agar screening (OAS) and chromogenic agar detection. All methods showed 100% specificity, but only the DD tests presented 100% sensitivity. The sensitivity of the other tests ranged from 82.2% (OAS)-98.3% (AD). The LA test showed the second lowest sensitivity (86.4%). The DD test showed high accuracy in the detection of MRSA isolates, but there was low precision in the detection of type IV isolates by the other tests, indicating that the genotypic characteristics of the isolates should be considered