36 research outputs found
Efecto del H2S en la Susceptibilidad al Agrietamiento de Dos Aceros Microaleados para Tubería
Cracking in sour media modes were observed, and these were related mainly to the microstructure produced during the thermomechanical process of two microalloyed steels grade API X 52. Through the use of linear elastic fracture mechanics modified specimens. Steels loaded at similar initial stress intensity factors showed different cracking modes that were related directly to their different microstructures. Steels microstructures indicate different fabrication routes. Testing temperature played an important role on switching the cracking characteristics being remarkable by the ferrite-pearlite steel microstructure. A banded microstructure is susceptible to the effects of hydrogen at room T. While, an acicular ferrite microstructure with carbides patches at grain boundaries is susceptible to anodic dissolution in front of the crack tip, no matter the temperature being tested. Key words: microalloyed steels, sour service, cracking modes, microstructure.
El sistema orexinérgico/hipocretinérgico y su rol en los trastornos del sueño
ResumenLas orexinas o hipocretinas son neuropéptidos recientemente descritos (1998), encontradosen mayor densidad en neuronas de las regiones lateral, posterior y perifornical del hipotálamo,las cuales se han visto implicadas en procesos de modulación de la ingesta alimenticiay del ciclo sueño-vigilia. El sistema orexinérgico tiene amplias proyecciones a todo lo largoy ancho del SNC especialmente a centros monoaminérgicos, tales como el locus coeruleus,núcleo tuberomamilar, núcleos del rafé y el área tegmental ventral. Inicialmente se pensóen un papel fundamental de las orexinas en la regulación de la función alimenticia, sinembargo estudios recientes han implicado a estos neuropéptidos en la regulación del ciclosueño-vigilia. Estos hallazgos permiten conocer mejor una región como el hipotálamo, aligual que brinda un mejor entendimiento de la patogenia y fisiopatología relacionadas conlos trastornos de la alimentación y el sueño. Este artículo pretende presentar una revisión lomás completa posible de lo que se conoce hasta ahora de estos neuromoduladores y su papelen relación con los trastornos del sueño, especialmente su implicación en la narcolepsia.Palabras clave: Orexinas, trastornos del sueño, narcolepsia, hipotálamo lateral.AbstractOrexins or hypocretins are recently described (1998) neuropeptides found in greater densityin hypothalamic neurons, wich have been shown to be important for modulating feedingand sleep-wakefulness cycle. Orexinergic system has broad projections throughoutthe length and breadth of the CNS specially to monoaminergic centers such as the locuscoeruleus, tuberoamilar neclei, raphe nuclei, and ventral tegmental area. Initially it wasthought a key role of orexin in feedin behavior regulation, however, recent studies give aleading role to these neuropeptides in regulating the sleep-wakefulness cycle, this discoveryopens a door to help better understand the operation of an area so important for thehomeostasis of the human body, such as the hypothalamus, and gives some basis for a betterunderstanding of the pathogenesis and pathophysiology in relation to eating disordersand sleep. The aim of this paper is to provide an updated review of the morphological andfunctional aspects that are known so far in relation to these molecules and their relationshipwith sleep disorders, especially their involvement in narcolepsy.Key words: Orexins, sleep disorders, narcolepsy, lateral hypothalamus
Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine
Background: Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis.Methodology/ Principal Findings: In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. on the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms.Conclusions/ Significance: These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates
First report on dung beetles in intra-Amazonian savannahs in Roraima, Brazil
This is the first study to address the dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) diversity in intra-Amazonian savannahs in the state of Roraima, Brazil. Our aim was to survey the dung beetle fauna associated with these savannahs (regionally called 'lavrado'), since little is known about the dung beetles from this environment. We conducted three field samples using pitfall traps baited with human dung in savannah areas near the city of Boa Vista during the rainy seasons of 1996, 1997, and 2008. We collected 383 individuals from ten species, wherein six have no previous record in intra-Amazonian savannahs. The most abundant species were Ontherus appendiculatus (Mannerheim, 1829), Canthidium aff. humerale (Germar, 1813), Dichotomius nisus (Olivier, 1789), and Pseudocanthon aff. xanthurus (Blanchard, 1846). We believe that knowing the dung beetles diversity associated with the intra-Amazonian savannahs is ideal for understanding the occurrence and distribution of these organisms in a highly threatened environment, it thus being the first step towards conservation strategy development
Taking the pulse of Earth's tropical forests using networks of highly distributed plots
Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of funding agencies. Here we show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots. We review the major scientific discoveries of this work and show how this process is changing tropical forest science. Our core approach involves linking long-term grassroots initiatives with standardized protocols and data management to generate robust scaled-up results. By connecting tropical researchers and elevating their status, our Social Research Network model recognises the key role of the data originator in scientific discovery. Conceived in 1999 with RAINFOR (South America), our permanent plot networks have been adapted to Africa (AfriTRON) and Southeast Asia (T-FORCES) and widely emulated worldwide. Now these multiple initiatives are integrated via ForestPlots.net cyber-infrastructure, linking colleagues from 54 countries across 24 plot networks. Collectively these are transforming understanding of tropical forests and their biospheric role. Together we have discovered how, where and why forest carbon and biodiversity are responding to climate change, and how they feedback on it. This long-term pan-tropical collaboration has revealed a large long-term carbon sink and its trends, as well as making clear which drivers are most important, which forest processes are affected, where they are changing, what the lags are, and the likely future responses of tropical forests as the climate continues to change. By leveraging a remarkably old technology, plot networks are sparking a very modern revolution in tropical forest science. In the future, humanity can benefit greatly by nurturing the grassroots communities now collectively capable of generating unique, long-term understanding of Earth's most precious forests.Additional co-authors: Susan Laurance, William Laurance, Francoise Yoko Ishida, Andrew Marshall, Catherine Waite, Hannsjoerg Woell, Jean-Francois Bastin, Marijn Bauters, Hans Beeckman, Pfascal Boeckx, Jan Bogaert, Charles De Canniere, Thales de Haulleville, Jean-Louis Doucet, Olivier Hardy, Wannes Hubau, Elizabeth Kearsley, Hans Verbeeck, Jason Vleminckx, Steven W. Brewer, Alfredo Alarcón, Alejandro Araujo-Murakami, Eric Arets, Luzmila Arroyo, Ezequiel Chavez, Todd Fredericksen, René Guillén Villaroel, Gloria Gutierrez Sibauty, Timothy Killeen, Juan Carlos Licona, John Lleigue, Casimiro Mendoza, Samaria Murakami, Alexander Parada Gutierrez, Guido Pardo, Marielos Peña-Claros, Lourens Poorter, Marisol Toledo, Jeanneth Villalobos Cayo, Laura Jessica Viscarra, Vincent Vos, Jorge Ahumada, Everton Almeida, Jarcilene Almeida, Edmar Almeida de Oliveira, Wesley Alves da Cruz, Atila Alves de Oliveira, Fabrício Alvim Carvalho, Flávio Amorim Obermuller, Ana Andrade, Fernanda Antunes Carvalho, Simone Aparecida Vieira, Ana Carla Aquino, Luiz Aragão, Ana Claudia Araújo, Marco Antonio Assis, Jose Ataliba Mantelli Aboin Gomes, Fabrício Baccaro, Plínio Barbosa de Camargo, Paulo Barni, Jorcely Barroso, Luis Carlos Bernacci, Kauane Bordin, Marcelo Brilhante de Medeiros, Igor Broggio, José Luís Camargo, Domingos Cardoso, Maria Antonia Carniello, Andre Luis Casarin Rochelle, Carolina Castilho, Antonio Alberto Jorge Farias Castro, Wendeson Castro, Sabina Cerruto Ribeiro, Flávia Costa, Rodrigo Costa de Oliveira, Italo Coutinho, John Cunha, Lola da Costa, Lucia da Costa Ferreira, Richarlly da Costa Silva, Marta da Graça Zacarias Simbine, Vitor de Andrade Kamimura, Haroldo Cavalcante de Lima, Lia de Oliveira Melo, Luciano de Queiroz, José Romualdo de Sousa Lima, Mário do Espírito Santo, Tomas Domingues, Nayane Cristina dos Santos Prestes, Steffan Eduardo Silva Carneiro, Fernando Elias, Gabriel Eliseu, Thaise Emilio, Camila Laís Farrapo, Letícia Fernandes, Gustavo Ferreira, Joice Ferreira, Leandro Ferreira, Socorro Ferreira, Marcelo Fragomeni Simon, Maria Aparecida Freitas, Queila S. García, Angelo Gilberto Manzatto, Paulo Graça, Frederico Guilherme, Eduardo Hase, Niro Higuchi, Mariana Iguatemy, Reinaldo Imbrozio Barbosa, Margarita Jaramillo, Carlos Joly, Joice Klipel, Iêda Leão do Amaral, Carolina Levis, Antonio S. Lima, Maurício Lima Dan, Aline Lopes, Herison Madeiros, William E. Magnusson, Rubens Manoel dos Santos, Beatriz Marimon, Ben Hur Marimon Junior, Roberta Marotti Martelletti Grillo, Luiz Martinelli, Simone Matias Reis, Salomão Medeiros, Milton Meira-Junior, Thiago Metzker, Paulo Morandi, Natanael Moreira do Nascimento, Magna Moura, Sandra Cristina Müller, Laszlo Nagy, Henrique Nascimento, Marcelo Nascimento, Adriano Nogueira Lima, Raimunda Oliveira de Araújo, Jhonathan Oliveira Silva, Marcelo Pansonato, Gabriel Pavan Sabino, Karla Maria Pedra de Abreu, Pablo José Francisco Pena Rodrigues, Maria Piedade, Domingos Rodrigues, José Roberto Rodrigues Pinto, Carlos Quesada, Eliana Ramos, Rafael Ramos, Priscyla Rodrigues, Thaiane Rodrigues de Sousa, Rafael Salomão, Flávia Santana, Marcos Scaranello, Rodrigo Scarton Bergamin, Juliana Schietti, Jochen Schöngart, Gustavo Schwartz, Natalino Silva, Marcos Silveira, Cristiana Simão Seixas, Marta Simbine, Ana Claudia Souza, Priscila Souza, Rodolfo Souza, Tereza Sposito, Edson Stefani Junior, Julio Daniel do Vale, Ima Célia Guimarães Vieira, Dora Villela, Marcos Vital, Haron Xaud, Katia Zanini, Charles Eugene Zartman, Nur Khalish Hafizhah Ideris, Faizah binti Hj Metali, Kamariah Abu Salim, Muhd Shahruney Saparudin, Rafizah Mat Serudin, Rahayu Sukmaria Sukri, Serge Begne, George Chuyong, Marie Noel Djuikouo, Christelle Gonmadje, Murielle Simo-Droissart, Bonaventure Sonké, Hermann Taedoumg, Lise Zemagho, Sean Thomas, Fidèle Baya, Gustavo Saiz, Javier Silva Espejo, Dexiang Chen, Alan Hamilton, Yide Li, Tushou Luo, Shukui Niu, Han Xu, Zhang Zhou, Esteban Álvarez-Dávila, Juan Carlos Andrés Escobar, Henry Arellano-Peña, Jaime Cabezas Duarte, Jhon Calderón, Lina Maria Corrales Bravo, Borish Cuadrado, Hermes Cuadros, Alvaro Duque, Luisa Fernanda Duque, Sandra Milena Espinosa, Rebeca Franke-Ante, Hernando García, Alejandro Gómez, Roy González-M., Álvaro Idárraga-Piedrahíta, Eliana Jimenez, Rubén Jurado, Wilmar López Oviedo, René López-Camacho, Omar Aurelio Melo Cruz, Irina Mendoza Polo, Edwin Paky, Karen Pérez, Angel Pijachi, Camila Pizano, Adriana Prieto, Laura Ramos, Zorayda Restrepo Correa, James Richardson, Elkin Rodríguez, Gina M. Rodriguez M., Agustín Rudas, Pablo Stevenson, Markéta Chudomelová, Martin Dancak, Radim Hédl, Stanislav Lhota, Martin Svatek, Jacques Mukinzi, Corneille Ewango, Terese Hart, Emmanuel Kasongo Yakusu, Janvier Lisingo, Jean-Remy Makana, Faustin Mbayu, Benjamin Toirambe, John Tshibamba Mukendi, Lars Kvist, Gustav Nebel, Selene Báez, Carlos Céron, Daniel M. Griffith, Juan Ernesto Guevara Andino, David Neill, Walter Palacios, Maria Cristina Peñuela-Mora, Gonzalo Rivas-Torres, Gorky Villa, Sheleme Demissie, Tadesse Gole, Techane Gonfa, Kalle Ruokolainen, Michel Baisie, Fabrice Bénédet, Wemo Betian, Vincent Bezard, Damien Bonal, Jerôme Chave, Vincent Droissart, Sylvie Gourlet-Fleury, Annette Hladik, Nicolas Labrière, Pétrus Naisso, Maxime Réjou-Méchain, Plinio Sist, Lilian Blanc, Benoit Burban, Géraldine Derroire, Aurélie Dourdain, Clement Stahl, Natacha Nssi Bengone, Eric Chezeaux, Fidèle Evouna Ondo, Vincent Medjibe, Vianet Mihindou, Lee White, Heike Culmsee, Cristabel Durán Rangel, Viviana Horna, Florian Wittmann, Stephen Adu-Bredu, Kofi Affum-Baffoe, Ernest Foli, Michael Balinga, Anand Roopsind, James Singh, Raquel Thomas, Roderick Zagt, Indu K. Murthy, Kuswata Kartawinata, Edi Mirmanto, Hari Priyadi, Ismayadi Samsoedin, Terry Sunderland, Ishak Yassir, Francesco Rovero, Barbara Vinceti, Bruno Hérault, Shin-Ichiro Aiba, Kanehiro Kitayama, Armandu Daniels, Darlington Tuagben, John T. Woods, Muhammad Fitriadi, Alexander Karolus, Kho Lip Khoon, Noreen Majalap, Colin Maycock, Reuben Nilus, Sylvester Tan, Almeida Sitoe, Indiana Coronado G., Lucas Ojo, Rafael de Assis, Axel Dalberg Poulsen, Douglas Sheil, Karen Arévalo Pezo, Hans Buttgenbach Verde, Victor Chama Moscoso, Jimmy Cesar Cordova Oroche, Fernando Cornejo Valverde, Massiel Corrales Medina, Nallaret Davila Cardozo, Jano de Rutte Corzo, Jhon del Aguila Pasquel, Gerardo Flores Llampazo, Luis Freitas, Darcy Galiano Cabrera, Roosevelt García Villacorta, Karina Garcia Cabrera, Diego García Soria, Leticia Gatica Saboya, Julio Miguel Grandez Rios, Gabriel Hidalgo Pizango, Eurídice Honorio Coronado, Isau Huamantupa-Chuquimaco, Walter Huaraca Huasco, Yuri Tomas Huillca Aedo, Jose Luis Marcelo Peña, Abel Monteagudo Mendoza, Vanesa Moreano Rodriguez, Percy Núñez Vargas, Sonia Cesarina Palacios Ramos, Nadir Pallqui Camacho, Antonio Peña Cruz, Freddy Ramirez Arevalo, José Reyna Huaymacari, Carlos Reynel Rodriguez, Marcos Antonio Ríos Paredes, Lily Rodriguez Bayona, Rocio del Pilar Rojas Gonzales, Maria Elena Rojas Peña, Norma Salinas Revilla, Yahn Carlos Soto Shareva, Raul Tupayachi Trujillo, Luis Valenzuela Gamarra, Rodolfo Vasquez Martinez, Jim Vega Arenas, Christian Amani, Suspense Averti Ifo, Yannick Bocko, Patrick Boundja, Romeo Ekoungoulou, Mireille Hockemba, Donatien Nzala, Alusine Fofanah, David Taylor, Guillermo Bañares-de Dios, Luis Cayuela, Íñigo Granzow-de la Cerda, Manuel Macía, Juliana Stropp, Maureen Playfair, Verginia Wortel, Toby Gardner, Robert Muscarella, Hari Priyadi, Ervan Rutishauser, Kuo-Jung Chao, Pantaleo Munishi, Olaf Bánki, Frans Bongers, Rene Boot, Gabriella Fredriksson, Jan Reitsma, Hans ter Steege, Tinde van Andel, Peter van de Meer, Peter van der Hout, Mark van Nieuwstadt, Bert van Ulft, Elmar Veenendaal, Ronald Vernimmen, Pieter Zuidema, Joeri Zwerts, Perpetra Akite, Robert Bitariho, Colin Chapman, Eilu Gerald, Miguel Leal, Patrick Mucunguzi, Miguel Alexiades, Timothy R. Baker, Karina Banda, Lindsay Banin, Jos Barlow, Amy Bennett, Erika Berenguer, Nicholas Berry, Neil M. Bird, George A. Blackburn, Francis Brearley, Roel Brienen, David Burslem, Lidiany Carvalho, Percival Cho, Fernanda Coelho, Murray Collins, David Coomes, Aida Cuni-Sanchez, Greta Dargie, Kyle Dexter, Mat Disney, Freddie Draper, Muying Duan, Adriane Esquivel-Muelbert, Robert Ewers, Belen Fadrique, Sophie Fauset, Ted R. Feldpausch, Filipe França, David Galbraith, Martin Gilpin, Emanuel Gloor, John Grace, Keith Hamer, David Harris, Tommaso Jucker, Michelle Kalamandeen, Bente Klitgaard, Aurora Levesley, Simon L. Lewis, Jeremy Lindsell, Gabriela Lopez-Gonzalez, Jon Lovett, Yadvinder Malhi, Toby Marthews, Emma McIntosh, Karina Melgaço, William Milliken, Edward Mitchard, Peter Moonlight, Sam Moore, Alexandra Morel, Julie Peacock, Kelvin Peh, Colin Pendry, R. Toby Pennington, Luciana de Oliveira Pereira, Carlos Peres, Oliver L. Phillips, Georgia Pickavance, Thomas Pugh, Lan Qie, Terhi Riutta, Katherine Roucoux, Casey Ryan, Tiina Sarkinen, Camila Silva Valeria, Dominick Spracklen, Suzanne Stas, Martin Sullivan, Michael Swaine, Joey Talbot, James Taplin, Geertje van der Heijden, Laura Vedovato, Simon Willcock, Mathew Williams, Luciana Alves, Patricia Alvarez Loayza, Gabriel Arellano, Cheryl Asa, Peter Ashton, Gregory Asner, Terry Brncic, Foster Brown, Robyn Burnham, Connie Clark, James Comiskey, Gabriel Damasco, Stuart Davies, Tony Di Fiore, Terry Erwin, William Farfan-Rios, Jefferson Hall, David Kenfack, Thomas Lovejoy, Roberta Martin, Olga Martha Montiel, John Pipoly, Nigel Pitman, John Poulsen, Richard Primack, Miles Silman, Marc Steininger, Varun Swamy, John Terborgh, Duncan Thomas, Peter Umunay, Maria Uriarte, Emilio Vilanova Torre, Ophelia Wang, Kenneth Young, Gerardo A. Aymard C., Lionel Hernández, Rafael Herrera Fernández, Hirma Ramírez-Angulo, Pedro Salcedo, Elio Sanoja, Julio Serrano, Armando Torres-Lezama, Tinh Cong Le, Trai Trong Le, Hieu Dang Tra
Estudio de la seroprevalencia de la infección por los virus linfotrópicos humanos (HTLV) I y II en poblaciones del departamento de Córdoba, Colombia
Introducción: Se determinó la seroprevalencia de los virus linfotrópicos humanos tipos
I y II (HTLV-I y II) en varios municipios del Departamento de Córdoba.
Materiales y métodos: Se analizaron 962 muestras de suero mediante la prueba de ELISA
y de Western blot confirmatorio. Se analizaron genéticamente 5 aislamientos virales por
RFLP y secuenciación de la región LTR.
Resultados: Se confirmaron 20 aislamientos como HTLV-I y uno como HTLV-II. La
seroprevalencia de la infección por el HTLV-I en la muestra obtenida del departamento
de Córdoba fue 2.1% (20/962), y para el HTLV-II 0.1% (1/962). Mediante análisis
genéticos se determinó que tres correspondieron al subtipo africano b y dos el cosmopolita
a.
Conclusión: Este es el primer registro de la infección tanto por HTLV-I como por HTLVII
informado para el departamento de Córdoba en Colombia.. Introduction. We studied the seroprevalence
of human lymphotropic virus
(HTLV) types I and II infection in
several towns of the Department of
Cordoba in the Colombian Caribbean
region.
Materials and methods. By ELISA
and Westen blot we screened a total of
962 sera. From proviral PBMC DNA of
five HTLV-I seropositive individuals
RFLP and sequencing of LTR region
was performed.
Results. Twenty samples were confirmed
as HTLV-I and one as HTLV-II.
The seroprevalence for HTLV-I in the
sample of the department of Cordoba
was 2.07% (20/962) and 0.104% (1/
962) for the HTLV-II. The genetic
analysis showed that three isolates were
classified as West African b and two as
Cosmopolitan a.
Conclusion. The present is the first
report of HTLV-I and II infection in
towns of Cordoba Department in Colombia
Estudio de la seroprevalencia de la infección por los virus linfotrópicos humanos (HTLV) I y II en poblaciones del departamento de Córdoba, Colombia
Introduction. We studied the seroprevalence of human lymphotropic virus (HTLV) types I and II infection in several towns of the Department of Cordoba in the Colombian Caribbean region.
Materials and methods. By ELISA and Westen blot we screened a total of 962 sera. From proviral PBMC DNA of five HTLV-I seropositive individuals RFLP and sequencing of LTR region was performed.
Results. Twenty samples were confirmed as HTLV-I and one as HTLV-II. The seroprevalence for HTLV-I in the sample of the department of Cordoba was 2.07% (20/962) and 0.104% (1/962) for the HTLV-II. The genetic analysis showed that three isolates were classified as West African b and two as Cosmopolitan a.
Conclusion. The present is the first report of HTLV-I and II infection in towns of Cordoba Department in Colombia.
RESUMEN
Introducción: Se determinó la seroprevalencia de los virus linfotrópicos humanos tipos I y II (HTLV-I y II) en varios municipios del Departamento de Córdoba.
Materiales y métodos: Se analizaron 962 muestras de suero mediante la prueba de ELISA y de Western blot confirmatorio. Se analizaron genéticamente 5 aislamientos virales por RFLP y secuenciación de la región LTR.
Resultados: Se confirmaron 20 aislamientos como HTLV-I y uno como HTLV-II. La seroprevalencia de la infección por el HTLV-I en la muestra obtenida del departamento de Córdoba fue 2.1% (20/962), y para el HTLV-II 0.1% (1/962). Mediante análisis genéticos se determinó que tres correspondieron al subtipo africano b y dos el cosmopolita a.
Conclusión: Este es el primer registro de la infección tanto por HTLV-I como por HTLV-II informado para el departamento de Córdoba en Colombia
El sistema orexinérgico/hipocretinérgico y su rol en los trastornos del sueño
ResumenLas orexinas o hipocretinas son neuropéptidos recientemente descritos (1998), encontradosen mayor densidad en neuronas de las regiones lateral, posterior y perifornical del hipotálamo,las cuales se han visto implicadas en procesos de modulación de la ingesta alimenticiay del ciclo sueño-vigilia. El sistema orexinérgico tiene amplias proyecciones a todo lo largoy ancho del SNC especialmente a centros monoaminérgicos, tales como el locus coeruleus,núcleo tuberomamilar, núcleos del rafé y el área tegmental ventral. Inicialmente se pensóen un papel fundamental de las orexinas en la regulación de la función alimenticia, sinembargo estudios recientes han implicado a estos neuropéptidos en la regulación del ciclosueño-vigilia. Estos hallazgos permiten conocer mejor una región como el hipotálamo, aligual que brinda un mejor entendimiento de la patogenia y fisiopatología relacionadas conlos trastornos de la alimentación y el sueño. Este artículo pretende presentar una revisión lomás completa posible de lo que se conoce hasta ahora de estos neuromoduladores y su papelen relación con los trastornos del sueño, especialmente su implicación en la narcolepsia.Palabras clave: Orexinas, trastornos del sueño, narcolepsia, hipotálamo lateral.AbstractOrexins or hypocretins are recently described (1998) neuropeptides found in greater densityin hypothalamic neurons, wich have been shown to be important for modulating feedingand sleep-wakefulness cycle. Orexinergic system has broad projections throughoutthe length and breadth of the CNS specially to monoaminergic centers such as the locuscoeruleus, tuberoamilar neclei, raphe nuclei, and ventral tegmental area. Initially it wasthought a key role of orexin in feedin behavior regulation, however, recent studies give aleading role to these neuropeptides in regulating the sleep-wakefulness cycle, this discoveryopens a door to help better understand the operation of an area so important for thehomeostasis of the human body, such as the hypothalamus, and gives some basis for a betterunderstanding of the pathogenesis and pathophysiology in relation to eating disordersand sleep. The aim of this paper is to provide an updated review of the morphological andfunctional aspects that are known so far in relation to these molecules and their relationshipwith sleep disorders, especially their involvement in narcolepsy.Key words: Orexins, sleep disorders, narcolepsy, lateral hypothalamus
Evaluation of ASTER and SRTM DEM data for lahar modeling: A case study on lahars from Popocatépetl Volcano, Mexico
Lahars are among themost serious and far-reaching volcanic hazards. In regions with potential interactions of lahars with populated areas and human structures the assessment of the related hazards is crucial for undertaking appropriate mitigating actions and reduce the associated risks. Modeling of lahars has become an important tool in such assessments, in particular where the geologic record of past events is insufficient. Mass-flow modeling strongly relies on digital terrain data. Availability of digital elevation models (DEMs), however, is often limited and thus an obstacle to lahar modeling.
Remote-sensing technology has now opened new perspectives in generating DEMs. In this study, we evaluate the feasibility of DEMs derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar TopographyMission (SRTM) for lahar modeling
on Popocatépetl Volcano, Mexico. Two GIS-based models are used for lahar modeling, LAHARZ and a flow-routing-based debris-flow model (modified single-flow direction model, MSF), both predicting areas potentially affected by lahars. Results of the lahar modeling show that both the ASTER and SRTM DEMs are basically suitable for use with LAHARZ and MSF. Flow-path prediction is found to be more reliable with SRTM data, though with a coarser spatial resolution. Errors of the ASTER DEMaffecting the prediction of flow paths due to the sensor geometry are associated with deeply incised gorges with north-facing slopes. LAHARZ is more sensitive to errors of the ASTER DEMthan theMSF model. Laharmodeling with the ASTERDEMresults in a more finely spaced predicted inundation area but does not add any significant information in comparisonwith the SRTMDEM.
Lahars at Popocatépetl are modeled with volumes of 1×105 to 8×106 m3 based on ice-melt scenarios of the glaciers on top of the volcano and data on recent and historical lahar events. As regards recently observed lahars, the travel distance of lahars of corresponding volume modeled with LAHARZ falls short by 2 to 4 km. An important finding is that the travel distance of potential lahar events modeled with LAHARZmay differ by about 2 km when using SRTMor ASTER data because of varying lateral flow-volume distribution. As a consequence, verification and sensitivity analysis of the DEMis fundamental to deriving hazard maps from predicted modeled inundation areas. Because of the global coverage of this type of remote-sensing data, the
conclusion that both SRTM and ASTER-derived DEMs are feasible for lahar modeling opens a wide field of application in volcanic-hazards studies