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San Marino.  


San Marino, an independent republic located in north central Italy, in 1983 had a population of 22,206 growing at an annual rate of .9%. The literacy rate is 97% and the infant mortality rate is 9.6/1000. The terrain is mountainous and the climate is moderate. According to local tradition, San Marino was founded by a Christian stonecutter in the 4th century A.D. as a refuge against religious persecution. Its recorded history began in the 9th century, and it has survived assaults on its independence by the papacy, the Malatesta lords of Rimini, Cesare Borgia, Napoleon, and Mussolini. An 1862 treaty with the newly formed Kingdom of Italy has been periodically renewed and amended. The present government is an alliance between the socialists and communists. San Marino has had its own statutes and governmental institutions since the 11th century. Legislative authority at present is vested in a 60-member unicameral parliament. Executive authority is exercised by the 11-member Congress of State, the members of which head the various administrative departments of the goverment. The posts are divided among the parties which form the coalition government. Judicial authority is partly exercised by Italian magistrates in civil and criminal cases. San Marino's policies are tied to Italy's and political organizations and labor unions active in Italy are also active in San Marino. Since World War II, there has been intense rivalry between 2 political coalitions, the Popular Alliance composed of the Christian Democratic Party and the Independent Social Democratic Party, and the Liberty Committee, coalition of the Communist Party and the Socialist Party. San Marino's gross domestic product was $137 million and its per capita income was $6290 in 1980. The principal economic activities are farming and livestock raising, along with some light manufacturing. Foreign transactions are dominated by tourism. The government derives most of its revenue from the sale of postage stamps to collectors around the world and from payment of an annual budget subsidy by the Italian government. Despite its close ties with Italy, San Marino has maintained its distinctive status for centuries. PMID:12178101



Dan Marino Helping Those with Autism Spectrum Disorders | NIH MedlinePlus the Magazine  


... Marino Foundation. Photo: Dan Marino Foundation Former NFL star quarterback Dan Marino and his wife Claire experienced ... to succeed in life,'" says the former NFL star. "That's where the focus for The Dan Marino ...


July 14, 2006: Consortium for Functional Glycomics, Pamela Marino

Paulson 2004 06/21/04 1 05/12/04 Consortium for Functional Glycomics Pamela A. Marino, Program Director Paulson 2004 06/21/04 2 05/12/04 Consortium for Functional Glycomics Define paradigms by which protein-carbohydrate


Hidráulica y transporte de sedimentos en ríos de montaña  

Microsoft Academic Search

RESUMEN: Actualmente el desarrollo de las áreas de montaña en el mundo hace que la hidráulica y el trans- porte de sedimentos en ríos de montaña sea un tema ampliamente tratado por varios investigadores, dada la complejidad de los mecanismos físicos que intervienen tanto en el proceso de flujo como en el de transporte. En este trabajo se ha realizado

D. F. García


Bridging the Gap Between Theory and Hardware Mario Marino, Gabriel Robins, Kevin Skadron, and Liang Wang  

E-print Network

of automatically translating theoretical computation models into an implementation-ready hardware description computational models, such as the Bounded-Error Quantum Polynomial-Time model employed in quantum computing [2Bridging the Gap Between Theory and Hardware Mario Marino, Gabriel Robins, Kevin Skadron, and Liang

Skadron, Kevin


An Analysis of Automatic Speech Recognition with Multiple Microphones Davide Marino and Thomas Hain  

E-print Network

substantial, typically error rate increases of more then 20% relative are observed. Microphone arrays can help time noise distortions are attenuated. Many ASR systems have made use of microphone arrays for bothAn Analysis of Automatic Speech Recognition with Multiple Microphones Davide Marino and Thomas Hain

Hain, Thomas


A population based study of Helicobacter pylori infection in a European country: the San Marino Study. Relations with gastrointestinal diseases  

Microsoft Academic Search

Helicobacter pylori is present worldwide but few large population studies exist on the epidemiology of the infection. A random cross sectional study was performed of H pylori infection in the adult population of San Marino, a European country with high gastric cancer rate, to assess its prevalence and to evaluate its relations with gastrointestinal disease. In 2237 subjects (77% of

G Gasbarrini; S Pretolani; F Bonvicini; M R Gatto; E Tonelli; F Mégraud; K Mayo; G Ghironzi; G Giulianelli; M Grassi



Radiobiological Studies with Monoenergetic Neutrons E. J. Hall; H. H. Rossi; A. M. Kellerer; L. Goodman; S. Marino  

E-print Network

. Goodman; S. Marino Radiation Research, Vol. 54, No. 3. (Jun., 1973), pp. 431-443. Stable URL: http://links.jstor by Radiation Research Society. Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at JSTOR's Terms and Conditions of Use


A fault-tolerant modular control approach to multi-robot perimeter patrol Alessandro Marino, Lynne E. Parker, Gianluca Antonelli, Fabrizio Caccavale and Stefano Chiaverini  

E-print Network

is focused on a a behavior-based approach to the problem of the multi-robot border patrollingA fault-tolerant modular control approach to multi-robot perimeter patrol Alessandro Marino, Lynne of the multi-robot patrolling problem. Along these directions, our approach has been validated in simulation

Parker, Lynne E.


Mass population screening for celiac disease in children: the experience in Republic of San Marino from 1993 to 2009  

PubMed Central

Background Prevalence of celiac disease in developed countries is assessed about 1:100–1:150. The real prevalence is unknown because mass screenings are expensive and difficult to organize. Moreover celiac disease can affect people at every age and studies on asymptomatic subjects at different ages are not comparable. In this study we wanted to know the real prevalence of celiac disease in children in the Republic of San Marino. We also analysed concordance of different tests used and costs of mass screening. Methods The study started in 1993. From 1993 to 1997 children aged 6, 10 and 14 were screened. Since 1997 only children aged 6 were monitored, in order to have a homogeneous population. In fact, every child born since 1980 was taken into account. Children were recruited by classroom lists of students for general paediatric examination. Until 2005 the screening test was based on dosage of antibodies anti-gliadin (AGA) IgA and IgG on venous blood. Since 2006 these tests were replaced by anti-transglutaminase IgA antibodies (ATTG). Anti-endomysial antibodies (EMA) were performed if result of any between either AGA or ATTG tests was positive or borderline; if EMA was positive, then an endoscopy with histological examination was performed to confirm the final diagnosis. Results Attendance to paediatric examination was 96%, submission to blood test was 87%. 42 on 5092 (0,8%; 1:125) children resulted affected by celiac disease. Histology always confirmed diagnosis by serology except for two cases. AGA test (until 2005) yielded 28 on 4304 (0,7% 1:143); ATTG test (since 2006) revealed 14 positive cases on 788 (1,8%; 1:55) leading to a larger percentage of diagnosis. EMA antibodies always confirmed positivity of ATTG. Conclusions Prevalence of celiac disease in children of Republic of San Marino is comparable to other North-European Countries. Sensitivity of ATTG proved much higher than that of anti-gliadin antibodies. Concordance between ATTG and EMA was 100%. Concordance between serology and histology was approximately 100%. Cost of screening was yearly about 5000 euros (250 children screened every year). PMID:24152602



The restart of meteorological observations in the 19th century in Lisbon: the contribution of Marino Miguel FRANZINI (1779-1861)  

NASA Astrophysics Data System (ADS)

After the early meteorological observations of the 1770s to the 1790s in continental Portugal (including a 5 year daily series by J. Velho), there were hardly any until 1815. In December 1815, a meteorological station was set up in Lisbon by Marino Miguel Franzini (1779-1861), an engineer who was also actively involved in Politics (liberal party). Following the tradition of the 18th century enlightenment movement, he took a keen interest in Nature and Sciences, particularly in the "influence" of weather and climate on health and agriculture. Franzini started his observations by request of a physician who sought to understand the reasons why the maximum mortality occurred on the summer months, unlike in northern countries of Europe where maximum mortality occurred in winter (as it happens nowadays in Portugal). The deterministic background of the two scientists is clear. Franzini was a member of the Lisbon Academy of Sciences (founded in 1799) and had contact with foreign Academies and foreign scientists. His instruments were carefully constructed and described, including graduation scales, and stations' location was indicated. Data from two years observations (several meteorological variables) was published in the Academy of Sciences Memoirs. From 1818 until 1826 and from 1835 until 1856 data was divulged in journals and newspapers, such as the "Journal of Medical Sciences", together with data on necrology in some of Lisbon parishes (illustrating the interest of physicians on weather); meteorological data and information about agriculture was also published in the "Lisbon Gazette". Unfortunately, there are hardly any daily data, as Franzini grouped his records according to weather types, as will be explained. Franzini's series will be presented in our talk. The gap between 1826 and 1835 was due to the political activities in which Franzini was involved: the civil war (liberals against absolutist) disruptedscientific research in Portugal. Official meteorological observations began in Lisbon,in December 1854, in a site not far away from Franzini's station. The long series of Lisbon includes the 1835-54 Franzini's series.

Alcoforado, Maria-Joao; Nunes, Fatima



With NSF support, Marino Xanthos,  

E-print Network

Mitra, professor of chemistry, is collaborating in an NIH-sponsored study to assess the potential biological and toxicological impacts of carbon nanotubes. 7 Cheul Cho, assistant professor of biomedical engi widespread meaningful use of health IT and facilitate use of an electronic health record for every person

Bieber, Michael



E-print Network

~ College Humanities sequ~nce integrates history, literature, and philosophy m a five-_guarter chronological, and the crisis in European culture smce 1848. Revelle Humanities measures critical thinking by good writing. Just writing and thinking in concrete, commonly understandable realities. We are not studying rhetorical

Russell, Lynn


LyricText: An Animated Display of Song Lyrics Rob Diaz-Marino1  

E-print Network

:// CR Categories: 1.3.8[Computer Graphics]: Applications Keywords: music, kinetic text, information about the mood of the singer, and can give insight into their speech and voice patterns. Lyric Typography [3] has been used to set mood and direct attention in Film and Television advertising. The Kinedit

Greenberg, Saul


PERCHE: A Public Registry for Choreographies Liliana Ardissono, Roberto Furnari, Anna Goy, Giovanna Petrone, Marino Segnan  

E-print Network

): in this perspective, the composition of Web Services can be viewed as the execution of a complex business process: When Web Service composition takes place in an open environment, involving services that belong: choreography, heterogeneous services interoperation, registry, service composition, service discovery, service

Goy, Anna


A Review of "Becoming Neapolitan. Citizen Culture in Baroque Naples" by John A. Marino  

E-print Network

century S. Giovanni had accumulated a week-long celebration with conspicuous popular involvement: the guilds decorated floats in the procession, there were mountains of free food, and there was nude bathing in the Bay of Naples. There was a... century S. Giovanni had accumulated a week-long celebration with conspicuous popular involvement: the guilds decorated floats in the procession, there were mountains of free food, and there was nude bathing in the Bay of Naples. There was a...

Litchfield, R. Burr



Classificação Textural de Sedimentos Praiais e a Relação com os Processos Morfogenéticos Eólicos e Marinhos  

Microsoft Academic Search

The quantification of morphodynamic parameters in a study of beach behavior and classification requires space-temporal observation of three variables: incident wave height and period, and settling velocity of grain size (Ws). The classic methodology of morphodynamic investigation is based on transverse topographic beach profiles suplemented by coastal sea condition observation and foreshore sand sampling. The sediments temporal flutuation on South



Basin boundary metamorphoses and phase J. M. Seoane, S. Zambrano, I. P. Mari~no and M. A. F. Sanjuan  

E-print Network

OFFPRINT Basin boundary metamorphoses and phase control J. M. Seoane, S. Zambrano, I. P. #12;May 2010 EPL, 90 (2010) 30002 doi: 10.1209/0295-5075/90/30002 Basin boundary PACS 05.45.Pq ­ Numerical simulations of chaotic systems Abstract ­ Basin boundary metamorphoses

Rey Juan Carlos, Universidad



Microsoft Academic Search

SUMMARY This paper used information collected by the Observer Program of the Tuna Fleet (PNOFA) between 1998 and 2007. The observers reported the presence of marine mammals when hauling in the drift pelagic longline and the incidental catches of this gear. Besides the killer whale (Orcinus orca), which had already been reported on several occasions, the species sighted were: sperm

Cecilia Passadore; María Szephegyi; Andrés Domingo


Bioenergetics and diving activity of internesting leatherback turtles Dermochelys coriacea at Parque Nacional Marino Las Baulas, Costa Rica.  


Physiology, environment and life history demands interact to influence marine turtle bioenergetics and activity. However, metabolism and diving behavior of free-swimming marine turtles have not been measured simultaneously. Using doubly labeled water, we obtained the first field metabolic rates (FMRs; 0.20-0.74 W kg(-1)) and water fluxes (16-30% TBW day(-1), where TBW=total body water) for free-ranging marine turtles and combined these data with dive information from electronic archival tags to investigate the bioenergetics and diving activity of reproductive adult female leatherback turtles Dermochelys coriacea. Mean dive durations (7.8+/-2.4 min (+/-1 s.d.), bottom times (2.7+/-0.8 min), and percentage of time spent in water temperatures (Tw) < or =24 degrees C (9.5+/-5.7%) increased with increasing mean maximum dive depths (22.6+/-7.1 m; all P< or =0.001). The FMRs increased with longer mean dive durations, bottom times and surface intervals and increased time spent in Tw< or =24 degrees C (all r2> or =0.99). This suggests that low FMRs and activity levels, combined with shuttling between different water temperatures, could allow leatherbacks to avoid overheating while in warm tropical waters. Additionally, internesting leatherback dive durations were consistently shorter than aerobic dive limits calculated from our FMRs (11.7-44.3 min). Our results indicate that internesting female leatherbacks maintained low FMRs and activity levels, thereby spending relatively little energy while active at sea. Future studies should incorporate data on metabolic rate, dive patterns, water temperatures, and body temperatures to develop further the relationship between physiological and life history demands and marine turtle bioenergetics and activity. PMID:16215215

Wallace, Bryan P; Williams, Cassondra L; Paladino, Frank V; Morreale, Stephen J; Lindstrom, R Todd; Spotila, James R



Uso de imagens LANDSAT como subsídio ao estudo da dispersão de sedimentos na região da foz do rio São Francisco  

Microsoft Academic Search

The construction of a sequence of water reservoirs along the lower São Francisco river basin has caused a severe change in the supply of water and sediments to the coastal zone. We present in this paper a first attempt to use Landsat data to estimate de Suspended Sediment Content (SSC) of the coastal plume. A simple log model proposed by

João Antonio Lorenzzetti; Eduardo Negri


Analise e Avaliacao Teorica dos Leiloes de Compra de Energia Eletrica Proveniente de Empreendimentos Existentes no Brasil  

Microsoft Academic Search

The reform process that the Brazilian electric industry has been undergoing since the mid 90's suffered a great inflection after the energy rationing of 2001 and the financial Revista EconomiA Set\\/Dez 2006

Tiago B. Correia; Elbia Melo


Different Limit to the Body's Ability of Increasing Fat-Free Mass Geltrude Mingrone, Simeone Marino, Andrea DeGaetano, Esmeralda Capristo, Steven B. Heymsfield,  

E-print Network

, age, and sex. Body composition data were obtained by isotopic dilution on 273 subjects ranging in body, increase-limited function of body weight. Model parameters were evaluated as functions of sex, age model (R 2 .95), with maximal AFT being determined by both sex and height and with AFT growth rate

Kirschner, Denise


A Designed Protein Interface That Blocks Fibril Formation Ushma J. Shukla, Heather Marino, Po-Ssu Huang, Stephen L. Mayo, and John J. Love*,  

E-print Network

-reactive protein has been shown to break down amyloid deposits in the body.3 In addition, Dumoulin et al. recently-B) altered their thermodynamic properties relative to the wild-type protein-G. The 12 mutations that resulted-A. Monomer-B fibrils were subjected to TEM imaging to confirm that the fibrils formed were indeed amyloid

Love, John J.


Relationship between PCBs in suspended and settled sediments from a coastal lagoon Relación entre PCBs en sedimentos suspendidos y depositados de una laguna costera  

Microsoft Academic Search

Polychlorinated biphenyl (PCB) congener concentrations and organic matter content were determined in 84 samples of suspended and settled sediments collected from six different locations in the Ria Formosa lagoon (Portugal). Total PCB (tPCB) concentrations were higher in the suspended matter (1.00-39.80 ng g -1 dw) than in the sediments (0.10-2.10 ng g -1 dw) and, in general, the same was

Luísa A. Barreira; Maria J. Bebianno; Stephen M. Mudge; Ana M. Ferreira; Clarisse I. Albino; Luís M. Veriato



Paleobiologia di un campione scheletrico tardoantico proveniente dal complesso paleocristiano di San Giusto (Lucera, V-VII secolo d.C.)  

Microsoft Academic Search

The cemetery area of San Giusto archaeological complex, especially the funerary basilica, seems to be a selective cemetery because of its considerable prevalence of male tombs, probable due to cultural reasons. The comparison of these samples with other skeleton remains proves that the samples in San Giusto cemetery have a moderate incidence of a porous hyperostosis and a tooth-socket pathology

Sublimi Saponetti; Patrizia Emanuel; Vito Scattarella


Use of digital multispectral videography to assess seagrass distribution in San Quintín Bay, Baja California, Mexico Uso de videografía multiespectral digital para evaluar la distribución del pasto marino en Bahía San Quintín, Baja California, México  

Microsoft Academic Search

Apparent threats to the spatial distribution of seagrass in San Quintín Bay prompted us to make a detailed assessment of habitats in the bay. Six coastal habitats and three seagrass subclasses were delineated using airborne digital multispectral videography (DMSV). Eelgrass, Zostera marina, was the predominant seagrass and covered 40% (1949 ha) of the areal extent of the bay in 1999.

David H. Ward; T. Lee Tibbitts; Alexandra Morton; Eduardo Carrera-González; Richard Kempka; Garza García



Caracterización bioquímica del pasto marino Zostera marina en el límite sur de su distribución en el Pacífico Norte Biochemical characterization of the eelgrass Zostera marina at its southern distribution limit in the North Pacific  

Microsoft Academic Search

The eelgrass Zostera marina L. is distributed along the Baja California Peninsula (Mexico) where it is exposed to a wide range of irradiances and temperatures that could promote changes in its biochemical composition. Consequently, the objective of this study was to characterize the variations in the levels of chlorophyll, carbohydrates, proteins, fiber, ash and calories in the shoots of Z.

Alejandro Cabello-Pasini; Raquel Muñiz-Salazar; David H. Ward


Contaminantes orgánicos persistentes en núcleos de sedimentos de la región sur de la Cuenca de las Californias Persistent organic pollutants in sediment cores from the southern region of the Bight of the Californias  

Microsoft Academic Search

In January 1998, four sediment cores were collected to reconstruct the history of contamination by persistent organic compounds in the southern region of the Bight of the Californias. Two groups of compounds were determined using chromatographic methods: petroleum hydrocarbons (aliphatic hydrocarbons, AHs, and polynuclear aromatic hydrocarbons, PAHs) and chlorinated hydrocarbons (pesticides and polychlorinated biphenyls, PCBs). The AHs had low concentrations,

D. I. Partida-Gutiérrez; J. A. Villaescusa


The MAJORANA DEMONSTRATOR A search for neutrinoless double-beta decay of germanium-76  

E-print Network

Rielage, Larry Rodriguez, Michael Ronquest, Harry Salazar, David Steele North Carolina State University, Jonathan Diaz, Peter J. Doe, Greg Harper, Robert Johnson, Andreas Knecht, Michael Marino, Mike Miller


LEVELS OF IMMUNOGLOBULIN-A IN TRACHEA, GUT AND BILE SAMPLES OF CHICKENS VACCINATED AGAINST NEWCASTLE DISEASE. Niveles de inmunoglobulina A en muestras de tráquea, intestino y bilis provenientes de aves vacunadas contra la enfermedad de Newcastle  

Microsoft Academic Search

Immunoglobulin-A (IgA) response to Newcastle diseases virus (NDV) vaccination was assessed using enzyme-linked immu- nosorbent assay. Total and NDV specific IgA levels were de- termined in tracheal washings, intestinal washings and bile. Chickens were primed with an in ovo recombinant avian adeno-associated vaccine coding for the NDV hemagglutinin- neuraminidase gene (rAAAV) and revaccinated with B1 or La- Sota strains of

Francisco Perozo; Giovanny Finol; Yaneth Mavárez


Numerical analysis of the hydrogeologic controls in a layered coastal aquifer system, Oahu, Hawaii, USA  

NASA Astrophysics Data System (ADS)

The coastal aquifer system of southern Oahu, Hawaii, USA, consists of highly permeable volcanic aquifers overlain by weathered volcanic rocks and interbedded marine and terrestrial sediments of both high and low permeability. The weathered volcanic rocks and sediments are collectively known as caprock, because they impede the free discharge of groundwater from the underlying volcanic aquifers. A cross-sectional groundwater flow and transport model was used to evaluate the hydrogeologic controls on the regional flow system in southwestern Oahu. Controls considered were: (a) overall caprock hydraulic conductivity; and (b) stratigraphic variations of hydraulic conductivity in the caprock. Within the caprock, variations in hydraulic conductivity, caused by stratigraphy or discontinuities of the stratigraphic units, are a major control on the direction of groundwater flow and the distribution of water levels and salinity. Results of cross-sectional modeling confirm the general groundwater flow pattern that would be expected in a layered coastal system. Groundwater flow is: (a) predominantly upward in the low-permeability sedimentary units; and (b) predominantly horizontal in the high-permeability sedimentary units. Résumé Le système aquifère littoral du sud d'Oahu (Hawaii, États-Unis) est constitué par des aquifères de terrains volcaniques très perméables, recouverts par des roches volcaniques altérées, et interstratifiés avec des sédiments marins et continentaux de perméabilité aussi bien forte que faible. Les roches volcaniques altérées et les sédiments sont globalement considérés comme une couverture, parce qu'ils s'opposent à l'écoulement de l'eau souterraine provenant des aquifères volcaniques sous-jacents. Les contrôles hydrogéologiques sur le système aquifère régional du sud-ouest d'Oahu ont étéévaluées au moyen d'un modèle d'écoulement et de transport sur une section transversale. Ces contrôles prennent en compte la conductivité hydraulique de la couverture dans son ensemble et les variations de la conductivité hydraulique liées à la stratigraphie de la couverture. A l'intérieur de la couverture, les variations de la conductivité hydraulique, dues à la stratigraphie ou à des discontinuités entre les unités stratigraphiques, sont le contrôle principal de la direction d'écoulement et de la répartition des niveaux et de la salinité de l'eau. La modélisation sur une section transversale a donné des résultats qui confirment l'organisation générale des directions d'écoulement, telle qu'elle pouvait être envisagée dans un aquifère littoral multicouche. L'écoulement souterrain est essentiellement vertical vers le haut dans les unités sédimentaires à faible perméabilité, et essentiellement horizontal dans les unités sédimentaires à forte perméabilité. Resumen El sistema acuífero costero de la zona sur de Oahu, en Hawaii, está formado por acuíferos volcánicos de alta permeabilidad, subyacentes a rocas volcánicas alteradas, con inclusiones de sedimentos marinos y terrestres, tanto de alta como de baja permeabilidad. Al conjunto de rocas volcánicas alteradas y sedimentos se le conoce por "tapón de roca", ya que impide la descarga libre de las aguas subterráneas del acuífero volcánico subyacente. Se usó un modelo de flujo de agua subterránea y transporte de solutos en sección vertical para evaluar los aspectos hidrogeológicos que controlan el flujo regional en la zona sudoeste de Oahu. Se consideraron: (a) la conductividad hidráulica global del tapón y (b) las variaciones estratigráficas de la conductividad hidráulica. En el tapón de roca, las variaciones de la conductividad hidráulica, causadas por la estratigrafía o por discontinuidades en las unidades estratigráficas, son las que controlan la dirección del flujo subterráneo y la distribución de niveles piezométricos y salinidad. Los resultados del modelo en sección transversal confirman la distribución del flujo subterráneo que cabría esperar en un sistema costero estrat

Oki, Delwyn S.; Souza, William R.; Bolke, Edward L.; Bauer, Glenn R.


Remember when you were a child and you shot up like a weed that one summer before  

E-print Network

in Autism 3 8 11Postdoctoral Training in Biobehavioral Intervention 5 Continued on page 2 TOMMYLAWSON was The Dan Marino Foundation announced a pledge of $1.2 million over 3 years to establish the Marino Autism and Research Institute for Autism Spectrum Disorders (TRIAD) and the University of Miami Center for Autism

Sarkar, Nilanjan


La Geologa: su filosofa y sus Angel F. Nieto-Samaniego  

E-print Network

un geólogo en la ciudad? Travertino (Hierve el Agua, Oax.) #12;#12;Geología La historia de las Rocas #12;Formación de rocas La acumulación de sedimentos (Agua) #12;Formación de rocas La acumulación de sedimentos (Agua) #12;Formación de rocas La acumulación de sedimentos (Agua) #12;Formación de rocas La

Bor, Gil


Biochemical characterization of the eelgrass Zostera marina at its southern distribution limit in the North Pacific [Caracterizacio??n bioqui??mica del pasto marino Zostera marina en el li??mite sur de su distribucio??n en el Paci??fico Norte  

USGS Publications Warehouse

The eelgrass Zostera marina L. is distributed along the Baja California Peninsula (Mexico) where it is exposed to a wide range of irradiances and temperatures that could promote changes in its biochemical composition. Consequently, the objective of this study was to characterize the variations in the levels of chlorophyll, carbohydrates, proteins, fiber, ash and calories in the shoots of Z. marina from the north (San Quintin) and south (Ojo de Liebre and San Ignacio lagoons) of the peninsula. Temperature in the southern lagoons was 5-6??C higher than in the northern lagoon; likewise, in situ irradiance was two-fold greater in the south than in the north. As a result of the lower irradiance levels, the concentration of chlorophyll in the shoots of Z. marina was twice as high (1.7 mg gWW-1) in the northern lagoon than in the southern ones (0.8 mg gWW-1). Similar to chlorophyll levels, the concentration of soluble carbohydrates in the shoots was greater in the northern lagoon than in the southern ones, suggesting that the high levels of chlorophyll are enough to compensate for the low irradiance levels and to maintain a positive carbon balance at San Quintin. On the other hand, the levels of proteins in the shoots from the north of the peninsula were slightly lower than those from the southern populations. In general, these results suggest that the different environmental conditions to which Z. marina is exposed along the peninsula impact its biochemical composition.

Cabello-Pasini, A.; Muniz-Salazar, R.; Ward, D.H.



Use of digital multispectral videography to assess seagrass distribution in San Quinti??n Bay, Baja California, Mexico [Uso de videografi??a multiespectral digital para evaluar la distributio??n del pasto marino en Bahi??a San Quinti??n, Baja California, Me??xico  

USGS Publications Warehouse

Apparent threats to the spatial distribution of seagrass in San Quinti??n Bay prompted us to make a detailed assessment of habitats in the bay. Six coastal habitats and three seagrass subclasses were delineated using airborne digital multispectral videography (DMSV), Eelgrass, Zostera marina, was the predominant seagrass and covered 40% (1949 ha) of the areal extent of the bay in 1999. Eelgrass grew over a wide range of tidal depths from about -3.0 in mean lower low water (MLLW) to about 1.0 m MLLW, but greatest spatial extent occurred in intertidal areas -0.6 m to 1.0 m MLLW. Exposed-continuous (i.e., high density) eelgrass was the most abundant habitat in the bay. Widgeongrass, Ruppia maritima, was the only other seagrass present and covered 3% (136 ha) of the areal extent of the entire bay. Widgeongrass grew in single species stands in the upper intertidal (??? 0.4 MLLW) and intermixed with eelgrass at lower tidal depths. Overall accuracy of the six habitat classes and three subclasses in the DMSV map was relatively high at 84%. Our detailed map of San Quintin Bay can be used in future change detection analyses to monitor the health of seagrasses in the bay.

Ward, D.H.; Tibbitts, T.L.; Morton, A.; Carrera-Gonzalez, E.; Kempka, R.



Astro Camp Counselors  

NASA Technical Reports Server (NTRS)

Barbara Marino (left), Stennis Space Center education technology specialist, shows Astro Camp Counselor Beverly Fitzsimmons a LEGO model during a teambuilding exercise May 29 at SSC's North Gate computer lab as a part of the counselors' `new hire' orientation.



8th. World Congress on Computational Mechanics (WCCM8) 5th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2008)  

E-print Network

8th. World Congress on Computational Mechanics (WCCM8) 5th European Congress on Computational-mail: Key Words: meshfree methods, point­sampled surfaces, thin shell analysis ABSTRACT

Huerta, Antonio


198 SDSU General Catalog 2012-2013 Computer Engineering  

E-print Network

198 SDSU General Catalog 2012-2013 Computer Engineering In the College of Engineering OFFICE., Panos Chair: Tummala Coordinator for Computer Engineering: Marino The Radio Frequency Communications and Computer Engineering Doctor of Philosophy degree in engineering sciences: (bioengineering), (electrical

Gallo, Linda C.


200 SDSU General Catalog 2013-2014 Computer Engineering  

E-print Network

200 SDSU General Catalog 2013-2014 Computer Engineering In the College of Engineering OFFICE., Panos Chair: Tummala Coordinator for Computer Engineering: Marino The Radio Frequency Communications and Computer Engineering Doctor of Philosophy degree in engineering sciences: (bioengineering), (electrical

Gallo, Linda C.


192 SDSU General Catalog 2010-2011 Computer Engineering  

E-print Network

192 SDSU General Catalog 2010-2011 Computer Engineering In the College of Engineering OFFICE: Tummala Coordinator for Computer Engineering: Marino The Radio Frequency Communications Systems Industry Assistant Professor: Sarkar Offered by the Department of Electrical and Computer Engineering Doctor

Gallo, Linda C.


196 SDSU General Catalog 2011-2012 Computer Engineering  

E-print Network

196 SDSU General Catalog 2011-2012 Computer Engineering In the College of Engineering OFFICE., Panos Chair: Tummala Coordinator for Computer Engineering: Marino The Radio Frequency Communications Engineering Doctor of Philosophy degree in engineering sciences: (bioengineering), (electrical and computer

Gallo, Linda C.


NU Intramural Sports 4 vs 4 Volleyball Rules  

E-print Network

games will be played at the Marino Center. Players must wear athletic clothing and appropriate footwear outside of the basketball court lines during play. Failure to do so will result in a point being awarded

Sridhar, Srinivas


26 CFR 1.955-4 - Definition of less developed country.  

...section with respect to— Australia Austria Belgium CanadaDenmark France Germany (Federal Republic) Hong Kong Italy Japan Liechtenstein Luxembourg Monaco Netherlands New Zealand Norway Union of South Africa San Marino...



An Evaluation of the TRIPS Computer System Mark Gebhart Bertrand A. Maher Katherine E. Coons Jeff Diamond Paul Gratz  

E-print Network

Diamond Paul Gratz Mario Marino Nitya Ranganathan Behnam Robatmili Aaron Smith James Burrill Stephen W in which blocks are composed of dataflow instructions. The goal of the TRIPS design is to mine concurrency

John, Lizy Kurian


Drugs of Abuse Pharm 4248 (2 credits) Fall 2012  

E-print Network

Stimulants (Methamphetamine, Ritalin) Montana Meth Marino (Chapter 5, p. 34-38) Oct 10 Hallucinogens (Ecstasy or MDMA) Ecstasy Rising Remmel (Chapter 8, p. 54-55) Oct 17 Depressants (Alcohol) Intervention Episode

Thomas, David D.


Deriving sediment quality guidelines in the Guadalquivir estuary associated with the Aznalcóllar mining spill: A comparison of different approaches Obtención de guías de calidad de sedimento en el estuario del Guadalquivir asociadas con el vertido minero de Aznalcóllar: Una comparación de diferentes métodos  

Microsoft Academic Search

Concentrations of heavy metals (Fe, Zn, Cd, Pb, Cu and Mn) and sediment toxicity tests (mortality of amphipods, Ampelisca brevicornis, of clams, Scrobicularia plana, and of fish, Solea senegalensis) were used to derive sediment quality guidelines (SQGs). The approaches are based on the determination of LC50, on the application of a multivariate analysis (MAA), and on the Threshold Effect Level

I. Riba; V. Zitko; J. M. Forja; T. A. DelValls



A review of "John Dryden: A Miscellany. And John Dryden (1631-1700): His Politics, His Plays, and His Poets." by Susan Green and Steven N. Zwicker eds. And Claude Rawson and Aaron Santesso eds.  

E-print Network

. San Marino, Cal.: Huntington Library, 2001. vii+255 pp. And Claude Rawson and Aaron Santesso, eds. John Dryden (1631-1700): His Politics, His Plays, and His Poets. Newark: University of Delaware Press, 2004. 301pp. Review by JEROME DONNELLY.... San Marino, Cal.: Huntington Library, 2001. vii+255 pp. And Claude Rawson and Aaron Santesso, eds. John Dryden (1631-1700): His Politics, His Plays, and His Poets. Newark: University of Delaware Press, 2004. 301pp. Review by JEROME DONNELLY...

Jerome Donnelly



Parasites of juvenile pompano from Galveston Island, Texas and preliminary trials of four chemicals for ectoparasitic activity  

E-print Network

taken from five different groups of pompano. The types of organisms which were isolated varied widely between groups. The bacteria 1 t d 1 fo ', h. ~h' ll d E t* h t 1, P d " ~11', P d 't 'f, P. p, "'d'd, P. p. , Pit? ~11 V. fuscus, V. marino... taken from five different groups of pompano. The types of organisms which were isolated varied widely between groups. The bacteria 1 t d 1 fo ', h. ~h' ll d E t* h t 1, P d " ~11', P d 't 'f, P. p, "'d'd, P. p. , Pit? ~11 V. fuscus, V. marino...

Coombs, Dan William



O "rompimento da caixa" e suas conseqüências na prática do projeto residencial no século XX.  

E-print Network

??Esta dissertação objetiva mostrar conseqüências ocorridas na prática do projeto residencial provenientes do ¿rompimento da caixa¿. O trabalho investiga um conjunto de residências unifamiliares concebidas… (more)

Merlin Janina Diemer



Energy impact of various inside air temperatures and humidities in a museum when located in five U. S. cities  

Microsoft Academic Search

The art conservation literature presents a wide range of recommended temperatures and relative humidities required to protect the safety of collections in museums, but the operating energy costs for specific criteria have not been identified. The Scott Gallery at the Huntington Library and Art Gallery in San Marino, CA, was selected for a detailed study of energy costs associated with

J. M. Ayres; H. Lau; J. C. Haiad



Fuzzy Behavioral Control for Multi-Robot Border Patrol  

E-print Network

Fuzzy Behavioral Control for Multi-Robot Border Patrol Alessandro Marino and Fabrizio Caccavale--This paper deals with the problem of multi-robot border patrolling. The patrolling algorithm is designed by three Pioneer robots. Index Terms--Behavioral control; Border Patrol; Platoon of vehicles; Multi

Parker, Lynne E.


Spring 2006 Anthropolog  

E-print Network

, "Archaeology and the Interpretation of Colonial Encounters, pp. 331-354, in G. J. Stein, ed., The Ar- chaeology Indians, Vol. 14: Southeast, specifically Paula Cardwell, Diane Della-Loggia, Cesare Marino, Roger Roop of Bruce D. Smith" (Fryxell symposium). "Archaeology From Behind the Blockade: New Re- search in Cuba

Mathis, Wayne N.


Eurographics/ ACM SIGGRAPH Symposium on Computer Animation (2008) M. Gross and D. James (Editors)  

E-print Network

approach is motivated by the behavior of a thin layer of fluid inserted in the empty space between nearly) Globally coupled collision handling using volume preserving impulses Eftychios Sifakis Sebastian Marino confounding cloth behaviors for digital costuming are external and self contact. Real and computer generated

Liblit, Ben



E-print Network

: Stephen A. Marino, M.S. Chief Physicist: Gerhard Randers-Pehrson, Ph.D. Funding During this year, we were delighted that NIH funding for continued development of our single-particle microbeam facility was renewed and awards from NIH, DOE, and NASA. Brief descriptions of these experiments are given here: Studies


Pratt & Whitney Two Dimensional HSR Nozzle Test in the NASA Lewis 9- By 15- Foot Low Speed Wind Tunnel: Aerodynamic Results  

NASA Technical Reports Server (NTRS)

This paper discusses a test that was conducted jointly by Pratt & Whitney Aircraft Engines and NASA Lewis Research Center. The test was conducted in NASA's 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT). The test setup, methods, and aerodynamic results of this test are discussed. Acoustical results are discussed in a separate paper by J. Bridges and J. Marino.

Wolter, John D.; Jones, Christopher W.



Unusual seasonal patterns and inferred processes of nitrogen retention in forested headwaters  

E-print Network

- ) loss from soils and streams, which contrib- utes to the acidification of soils and surface waters and to eutrophication of coastal ecosystems down- stream (e.g., Howarth et al. 2000; Aber et al. 2003; Driscoll et al to the Chesapeake Bay, where excess N drives eutrophication and hypoxia (Hagy et al. 2004; Howarth and Marino 2006

Elliott, Emily M.


Updated On: 4/12/2013 15:01 Teams: Galactic Unicorns points Yeah Dawg points  

E-print Network

Daniel Bartlett - C 5 Uri Litvin - C 0 Rob Toombs 2 Alberto Cohen 0 Chris Alexander 3 David Zebede 0 Dan Conner Peterson - *Ineligible* 0 Kathryn Terrell 0 Matthew Sullivan 0 Ryan Bell 0 Jacque Moore 0 Meryl Olofsson 1 Benjamin Bungert 0 James Marino 0 Adam Swatt 0 Shane Sullivan 0 Ryan Sweezey 0 Tyler Burns 0

Sridhar, Srinivas


ORIGINAL ARTICLE ApoA-1 mimetic restores adiponectin expression and  

E-print Network

disease; female obesity; heme oxygenase INTRODUCTION Obesity affects over 72 million adults in the United States with a disproportionate prevalence in women.1,2 Moderate to severe obesity is associated of changes in body weight in female obese mice JS Marino1 , SJ Peterson2 , M Li1 , L Vanella1 , K Sodhi1 , JW

Toledo, University of


Camden Campus Last updated 3/14  

E-print Network

, Athletics James Marino Assistant Dean Career Center Maria Serra Director, Health Services Kristin Walker, CCIB Timothy Martin Director Honors College Charlene Mires Director, MARCH Cyril Reade Director, Center, School Nurse Certification Program Carol Germain Senior Advisor, Scholarship/Research Nancy Powell

Hanson, Stephen José


The effects of nest environment on calcium mobilization by leatherback turtle embryos ( Dermochelys coriacea) during development  

Microsoft Academic Search

We investigated the effect of sand moisture content and sand temperature on developmental success and the mobilization of calcium during development using laboratory incubated eggs (n=251) collected from leatherbacks nesting at Parque Nacional Marino Las Baulas, Costa Rica. Calcium concentrations of egg components [eggshell, yolk plus albumen (Y+A) and embryo] changed significantly through incubation for both viable and undeveloped eggs.

Joseph J Bilinski; Richard D Reina; James R Spotila; Frank V Paladino



Journal of Theoretical Biology 227 (2004) 463486 The human immune response to Mycobacterium tuberculosis in  

E-print Network

tuberculosis in lung and lymph node Simeone Marino*, Denise E. Kirschner Department of Microbiology Abstract A key issue for the study of tuberculosis is to understand why individuals infected with Mycobacterium tuberculosis (Mtb) experience different clinical outcomes. To better understand the dynamics

Kirschner, Denise


Abstract The pathologic hallmark of tuberculosis is the granuloma. A granuloma is a multifaceted cellular structure that serves to focus the host immune response,  

E-print Network

127 Abstract The pathologic hallmark of tuberculosis is the granuloma. A granuloma tuberculosis infection, and if a granuloma is capable of inhibiting or killing most of the M. tuberculosis Granuloma Formation and Function in Tuberculosis Mohammad Fallahi-Sichani, Simeone Marino, JoAnne L. Flynn

Kirschner, Denise


Mycobacterium tuberculosis as viewed through a computer  

E-print Network

Mycobacterium tuberculosis as viewed through a computer Denise Kirschner and Simeone Marino of Mycobacterium tuberculosis and the immune system. Different mathematical models were formulated on the basis that contribute to the success of M. tuberculosis as a human pathogen. Our goal is to stimulate experimentation

Kirschner, Denise


TNF and IL-10 are major factors in modulation of the phagocytic cell environment in lung and lymph node in tuberculosis: A next-generation  

E-print Network

node in tuberculosis: A next-generation two-compartmental model Simeone Marino a , Amy Myers b , Jo a c t Tuberculosis (TB) is one of the earliest recorded human diseases and still one of the deadliest worldwide. Its causative agent is the bacteria Mycobacterium tuberculosis (Mtb). Cytokine

Kirschner, Denise


Wastewater and Watershed Influences on Primary Productivity and Oxygen Dynamics in the Lower Hudson River Estuary  

E-print Network

University of New York, Syracuse, NY 13210 #12;Abstract: Primary productivity in the saline Hudson RiverWastewater and Watershed Influences on Primary Productivity and Oxygen Dynamics in the Lower Hudson River Estuary Robert W. Howarth1, 2 , Roxanne Marino1, 2 Dennis P. Swaney2 , and Elizabeth W. Boyer3 1

Limburg, Karin E.


Exp Brain Res DOI 10.1007/s00221-013-3467-7  

E-print Network

the body image, regarded as a pictorial description of the body which is mainly based on visual the propriocep- tive input for motor control. Keywords Body schema · Body image · Body-size distortion · Reach the visual size of the body recalibrates the body schema N. F. Bernardi · B. F. Marino · A. Maravita · G

Malfait, Nicole



E-print Network

on planktonic nitrogen fixation in saline estuaries. I. Nutrient and trophic controls Roxanne Marino1, 2 N2 into available nitrogen (N) are common and critically important to nutrient cycling in many lakes development of planktonic, N-fixing cyanobacterial blooms in estuaries. KEY WORDS: Nitrogen fixation

Likens, Gene E.


LGBTQ Civil Rights: A Global Perspective 19th century  

E-print Network

1861 is amended to remove the death sentence for "buggery" (which had not been used since 1836). The penalty became imprisonment from 10 years to life. 1865 ­ San Marino decriminalizes sodomy. 1867 in Britain's history fails. 1923 ­ The word fag is first used in print in reference to gays in Nels Anderson


en las ciencias marinas Revista Universitaria  

E-print Network

animales, alimento principal de estos seres marinos. A partir de una recopilación de lo mejor de los que las estrellas de mar son animales que ejecutan su movimiento gracias a que están llenas de agua

Hernández-Walls, Rafael


Orlando 2014 Aprender ingls en familia... En EEUU!  

E-print Network

actividades científicas, artísticas, y lúdicas. Clases teóricas sobre hábitats y alimentación de los animales marinos y clases prácticas "behind the scenes" donde darán de comer a los animales, tocarán, y verán de

Oro, Daniel


Events, Magazines and Internal Communication Office | University of Trento | tel. + 39 0461 28322832251133 | fax +39 0461 282899  

E-print Network

, September 5th , 2012 Morning: session II "The brain cancer stem cell" 9.00 AM Peter Dirks (Toronto, Canada Steve Pollard (London, UK) Epigenetic reprogramming of brain cancer stem cells 11.45 AM Silvia Marino, September 8th , 2012 Morning: session V "Targeting the brain cancer stem cell" 9.00 AM Gaetano Finocchiaro


Why Should Community College Faculty Write Grant Proposals?  

Microsoft Academic Search

Community colleges have seen dramatic enrollment increases (Kasper, 2002), and some are now offering 4-year degrees (Evelyn, 2003). They are eligible for more grants than in the past, and community college funding from state and federal appropriations is shrinking (Lawrence & Marino, 2003). For these reasons, it is imperative that community college faculty become involved in grant proposal preparation and

Phyl Renninger; Anne Meilof; Todd Pitts; Janie K. Smalley



Why Should Community College Faculty Write Grant Proposals?  

ERIC Educational Resources Information Center

Community colleges have seen dramatic enrollment increases (Kasper, 2002), and some are now offering 4-year degrees (Evelyn, 2003). They are eligible for more grants than in the past, and community college funding from state and federal appropriations is shrinking (Lawrence & Marino, 2003). For these reasons, it is imperative that community…

Renninger, Phyl; Meilof, Anne; Pitts, Todd; Smalley, Janie



Biol. Rev. (2008) doi:10.1111/j.1469-185X.2008.00049.x  

E-print Network

to Manger's thermogenesis hypothesis of cetacean brain structure Lori Marino1 *, Camilla Butti2,3 , Richard by social and ecological forces. Key words: brain, brain size, marine mammals, thermogenesis, intelligence ..................................................... 2 (1) The real test of the thermogenesis hypothesis is in the Eocene

Hawaii at Hilo, University of


Biol. Rev. (2008), 83, pp. 417440. 417 doi:10.1111/j.1469-185X.2008.00049.x  

E-print Network

of evidence: reply to Manger's thermogenesis hypothesis of cetacean brain structure Lori Marino1 *, Camilla by social and ecological forces. Key words: brain, brain size, marine mammals, thermogenesis, intelligence ..................................................... 418 (1) The real test of the thermogenesis hypothesis is in the Eocene

Lefebvre, Louis



EPA Science Inventory

NRMRL-ADA-00230 Hantush*, M.M., Govindaraju, R.S., and Marino, M.A. Screening Model for Volatile Pollutants in Duel Porosity Soils. Journal of Hydrology 260:58-74 (2000). EPA/600/J-02/172. This paper develops mass fraction models for transport and fate of volatile organic chemi...


Graduate Studies Committee January 31, 2012  

E-print Network

; deployment; management. ENTRP 502: Business Planning ­ [Corbett] The purpose of this course is to learn how to successfully develop a business plan for a new business venture. ES/RP 501: Graduate Skills Seminar ­ [Marino] May be repeated for credit; cumulative maximum 12 hours. Continuous enrollment required for regularly

Collins, Gary S.


Central insulin and leptin-mediated autonomic control of glucose  

E-print Network

Central insulin and leptin-mediated autonomic control of glucose homeostasis Joseph S. Marino1,2 , Yong Xu4 and Jennifer W. Hill1,2,3 1 Center for Diabetes and Endocrine Research, College of Medicine, the incidence of type 2 diabetes is escalating rapidly. Type 2 diabetes results from multi-organ dysfunctional

Toledo, University of


An Analysis of Linux Scalability to Many Cores 1 / 44 An Analysis of Linux Scalability to Many Cores  

E-print Network

An Analysis of Linux Scalability to Many Cores 1 / 44 An Analysis of Linux Scalability to Many Cores Peter Tsonchev Ilias Marinos University College London 19 March 2012 #12;An Analysis of Linux Evaluation 5 Conclusions #12;An Analysis of Linux Scalability to Many Cores 3 / 44 Introduction Introduction

Karp, Brad


Jeudi 24 septembre 2009Jeudi 24 septembre 2009Jeudi 24 septembre 2009Jeudi 24 septembre 2009 Muse d'Art et d'Histoire du Judasme (Auditorium)  

E-print Network

cosmopolitisme Présidence de séance : Astrid STARCK-ADLER · 09h30-10h00 : MarinoGiuseppeGiuseppeGiuseppe BBBBEVILACQUAEVILACQUAEVILACQUAEVILACQUA (Università di Firenze) : Alfred Döblin und Joseph Roth. Aktive Erwartung und Resignation · 15h15


Concepts & Procedures. [SITE 2002 Section].  

ERIC Educational Resources Information Center

This document contains the following full and short papers on concepts and procedures from the SITE (Society for Information Technology & Teacher Education) 2002 conference: "Exploring Minds Network" (Marino C. Alvarez and others); "Learning Communities: A Kaleidoscope of Ecological Designs" (Alain Breuleux and others); "PDA's and Research: A…

Sarner, Ronald, Ed.; Mullick, Rosemary J., Ed.; Bauder, Deborah Y., Ed.



EPA Science Inventory

NRMRL-ADA-00232 Hantush*, M.M., Harada, M., and Marino, M.A. On the Hydraulics of Stream Flow Routing with Bank Storage. Journal of Hydrologic Engineering 7 (1):76-89 (2002). EPA/600/J-02/173. Bank storage is a process in which volumes o...


Unfaithful Glitch Propagation in Existing Binary Circuit Models  

E-print Network

Unfaithful Glitch Propagation in Existing Binary Circuit Models Matthias F¨ugger Embedded Computing that no existing continuous-time, binary value-domain model for digital circuits is able to correctly capture models, which follows from well-known results on the behavior of bi-stable circuits obtained by Marino

Paris-Sud XI, Université de



Microsoft Academic Search

Resumo - Os hidratos de metano constituem uma fonte interessante de ener- gia cujas reservas oceânicas recenseadas em 2001 foram estimadas em duas vezes as reservas conhecidas de gás natural, petróleo e carvão reunidas. Encontram-se nos sedimentos marinhos das margens continentais, e a fraca profundidade, no perma- frost. Tendo em conta a necessidade crescente da sociedade em energia e o





Microsoft Academic Search

La Confederación Hidrográfica del Ebro detectó en 1993 la necesidad de llevar a cabo un proyecto de rehabilitación de los desagües de fondo del embalse de Joaquín Costa (Barasona). La justificación de esta actuación radicaba en la necesidad de reparar las compuertas de fondo de la presa (mecanismos de apertura y cierre) y de retirar los sedimentos acumulados en el

Jorge Alcázar; Isabel Ferrán




Microsoft Academic Search

RESUMEN: En este artículo se estudia la capacidad de las corrientes de densidad, formadas por diferencia de temperatura, para resuspender el sedimento en el fondo de un embalse. El estudio se enmarca dentro de un suceso de contaminación que se produjo en el embalse de Flix en 2001, en el que murieron varios miles de peces y se vio afectada

Albert Herrero Casas; Vicente Medina Iglesias; Allen Bateman Pinzón


Identifying coseismic subsidence in tidal-wetland stratigraphic sequences at the Cascadia subduction zone of western North America  

Microsoft Academic Search

Tidal-wetland stratigraphy reveals that great plate boundary earthquakes have caused hundreds of kilometers of coast to subside at the Cascadia subduction zone. However, determining earthquake recurrence intervals and mapping the coastal extent of past great earthquake ruptures in this region are complicated by the effects of many sedimento!ogic, hydrographic, and oceanographic processes that occur on the coasts of tectonically passive

Alan R. Nelson; Ian Shennan; Antony J. Long



SCRS/2012/168 Collect. Vol. Sci. Pap. ICCAT, 69(5): 2087-2102 (2013) SEAMOUNTS AND TUNA FISHERIES: TUNA HOTSPOTS OR  

E-print Network

montes marinos activos basada en análisis del tiempo de pesca de las flotas y de patrones de puntos seleccionados con este método en el océano Atlántico durante el periodo 1999-2010 para las flotas rancesas y ambas flotas. Hay cambios en la composición por especies ya que aumenta la proporción de patudo en las

Paris-Sud XI, Université de


Astronomy & Astrophysics manuscript no. 2516 June 16, 2006 (DOI: will be inserted by hand later)  

E-print Network

to the solar cycle are not common among young stars. Indications of spectral variability was found in one star-term variability of low mass stars is present in all stellar life phases while long-term variations have never been-ray variability of NGC 2516 stars in the XMM-Newton observations A. Marino1, G. Micela2, I. Pillitteri1, and G


Influence of predation by a crab on the distribution of the size-groups of three intertidal gastropods in South Australia  

Microsoft Academic Search

Two South Australian rocky intertidal platforms were sampled in April 1981 and December 1982 (Marino Rocks) and in December 1982 (Lady Bay), respectively. Three snail species, Nerita atramentosa Reeve, 1855, Bembicium nanum (Lamarck, 1822) and Austrocochlea concamerata (Wood, 1828), exhibited shore-level size-gradients, with smaller individuals occupying the higher intertidal levels. The reef crab (Ozius truncatus M.-Edwards, 1834), whose distribution overlaps

N. B. Chilton; C. M. Bull



New books in review  

Microsoft Academic Search

12 AMERICANS SPEAK. Facsimiles of Original Editions selected and annotated by John E. Pomfret. San Marino, Calif: Hunting?ton Library, 1954; pp. vi+183. $5.00.AMERICAN DEMAGOGUES: TWENTIETH CENTURY. By Reinhard H. Luthin. Boston: The Beacon Press, 1954; pp. xv+368. $5.00,ADVENTURES IN POLITICS: WE GO TO THE LEGISLATURE. By Richard L. Neuberger. New York: Oxford University Press, 1954; pp. 203. $3.50.CIVILIZATION AND THE

Wilbur Samuel Howell; Barnet Baskerville; Robert D. Clark; James J. Murphy; Guy A. Cardwell; Jonathan Curvin; Russell W. Lembke; Harold Ehrensperger; E. J. West; Albert E. Johnson; Fairfax Proudfit Walkup; John T. Dugan; Edwin Duerr; Claude L. Shaver; Harold P. Zelko; Harold F. Harding; John Robson; Roy F. Hudson; Paul C. Boomsliter; R. S. Brubaker; John Keltner; Elwood Murray; John P. Highlander; Willard Bellman; E. Winston Jones



UNAM har monitoreo de cambio climtico en mares -El Universal -Ciencia[06/12/2011 18:05:03  

E-print Network

noviembre de 2011 Redacción | El Universal 00:07 Comenta la Nota Con la finalidad de evaluar impactos del Roo. Entre los impactos del cambio climático relacionados con el medio marino destacan el aumento en disminución o migración de las especies, el aumento de salinidad, pérdidas de turismo y daños a las

Islas, León


The Chemistry of Coffee  

NSDL National Science Digital Library

The paper Our Everyday Cup of Coffee: The Chemistry behind Its Magic by Marino Petracco provides a hearty blend of molecules for this month. The author deals with coffee at a number of different levels ranging from the economic and social to the still perplexing questions of flavor and aroma. The associated molecules demonstrate a range of structural features that students will benefit from examining in three dimensions.


Formulae of one-partition and two-partition Hodge integrals  

E-print Network

Based on the duality between open-string theory on noncompact Calabi-Yau threefolds and Chern-Simons theory on three manifolds, M Marino and C Vafa conjectured a formula of one-partition Hodge integrals in term of invariants of the unknot (hep-th/0108064). Many Hodge integral identities, including the lambda_g conjecture and the ELSV formula, can be obtained by taking limits of the Marino-Vafa formula. Motivated by the Marino-Vafa formula and formula of Gromov-Witten invariants of local toric Calabi-Yau threefolds predicted by physicists, J Zhou conjectured a formula of two-partition Hodge integrals in terms of invariants of the Hopf link (math.AG/0310282) and used it to justify physicists' predictions (math.AG/0310283). In this expository article, we describe proofs and applications of these two formulae of Hodge integrals based on joint works of K Liu, J Zhou and the author (math.AG/0306257, math.AG/0306434, math.AG/0308015, math.AG/0310272). This is an expansion of the author's talk of the same title at the BIRS workshop: "The Interaction of Finite Type and Gromov-Witten Invariants", November 15--20, 2003.

Chiu-Chu Melissa Liu



V Festival Iberoamericano de Teatro de Bogotá  

E-print Network

dineros provenientes del narcotráfico en la campaña presidencial - y se lanzaron con gran entusiasmo a disfrutar de los 32 países, 86 compañías, 484 espectáculos y 1800 artistas que se tomaron 23 escenarios de la capital para celebrar el V Festival...

Garavito, Lucí a



Representación y justicia en Manda patibularia de Santiago García  

E-print Network

el mundo. En efecto, a nivel nacional, la problemática del narcotráfico, de las cárceles de alta seguridad, y del llamado "Proceso 8000" relacionado con la infiltración de dinero proveniente del narcotráfico en la campaña presidencial de Ernesto...

Garavito, Lucí a



Periglacial landscape evolution and environmental changes of Arctic lowland areas for the last 60000 years (western Laptev Sea coast, Cape Mamontov Klyk)  

Microsoft Academic Search

Non-glaciated Arctic lowlands in north-east Siberia were subjected to extensive landscape and environmental changes during the Late Quaternary. Coastal cliffs along the Arctic shelf seas expose terrestrial archives containing numerous palaeoenvironmental indicators (e.g., pollen, plant macro-fossils and mammal fossils) preserved in the permafrost. The presented sedimento- logical (grain size, magnetic susceptibility and biogeochemical parameters), cryolithological, geochronological (radiocarbon, accelerator mass spectrometry

Lutz Schirrmeister; Guido Grosse; Viktor Kunitsky; Diana Magens; Hanno Meyer; Alexander Dereviagin; Tatyana Kuznetsova; Andrei Andreev; Olga Babiy; Frank Kienast; Mikhael Grigoriev; Pier Paul Overduin; Frank Preusser



LO SABA?... Jobbagy, Mercau & Nosetto  

E-print Network

zona saturada (todos los poros ocupados por agua) del perfil de un suelo/sedimento. Los hidrólogos las Verdadera. ZONA CAPILAR 1 El agua asciende sobre la altura de la napa por los capilares del suelo. En.0-1.5 m por sobre la napa. En suelos más arenosos hasta 0.5-1.0 m. En suelos más arcillosos la tasa de

Nacional de San Luis, Universidad


Identificacin de Humedales en Puerto Rico utilizando Imgenes Multiespectrales Lola Xiomara Bautista Rozo  

E-print Network

áreas cuyos suelos están saturados con agua durante toda la parte del tiempo y que alberga plantas características de suelos hidrícos. Son excelentes filtros biológicos y reducen el movimiento de nutrientes hacia suelo, la hidrología y la vegetación. El suelo se compone primordialmente de sedimentos anaeróbicos y

Gilbes, Fernando


Beautiful Science: Worth a Visit  

NASA Astrophysics Data System (ADS)

For those in the profession of teaching physics who reside in or plan to visit the Los Angeles area, I would highly recommend a trip to the Huntington Library in San Marino, specifically to a permanent exhibit entitled "Beautiful Science: Ideas that Changed the World" in the Dibner Hall of the History of Science. The exhibit contains original books and manuscripts from the library's own collections. The sheer magnitude of human achievement represented here and the amount of effort and money that must have been required to amass these books boggles the mind.

Bingham, Frederick M.



Convergence theorems of fixed points for Lipschitz pseudo-contractions in Hilbert spaces  

NASA Astrophysics Data System (ADS)

Let C be a closed convex subset of a real Hilbert space H and assume that T is a [kappa]-strict pseudo-contraction on C. Consider Mann's iteration algorithm given by It is proved that if the control sequence {[alpha]n} is chosen so that [kappa]<[alpha]n<1 and , then , where A=I-T and d(0,D) denotes the distance between the origin and the subset set D of H. As a consequence of this result, we prove that if T has a fixed point in C, then {xn} converges weakly to a fixed point of T. Also, we extend a result due to Reich to [kappa]-strict pseudo-contractions in the Hilbert space settingE Further, by virtue of hybridization projections, we establish a strong convergence theorem for Lipschitz pseudo-contractions. The results presented in this paper improve or extend the corresponding results of Browder and Petryshyn [F.E. Browder, W.V. Petryshyn, Construction of fixed points of nonlinear mappings in Hilbert spaces, J. Math. Anal. Appl. 20 (1967) 197-228], Rhoades [B.E. Rhoades, Fixed point iterations using infinite matrices, Trans. Amer. Math. Soc. 196 (1974) 162-176] and of Marino and Xu [G. Marino, H.-K. Xu, Weak and strong convergence theorems for strict pseudo-contractions in Hilbert spaces, J. Math. Anal. Appl. 329 (1) (2007) 336-346].

Zhou, Haiyun



Posibles implicaciones de la legalización del consumo, Producción y comercialización de las drogas en Colombia  

Microsoft Academic Search

Como reacción ante el aparente fracaso de la estrategia represiva de lucha contra las drogas ilícitas y debido al incremento considerable del conflicto en Colombia, el debate sobre las bondades y males de la legalización ha cobrado especial interés en el país. Propuestas provenientes de distintos sectores sociales, políticos y académicos coinciden en que para desincentivar el negocio del narcotráfico,




Senderos Geo-Arqueolgicos, 7 (2010) Geologa, aguas, romanos y romnico  

E-print Network

Senderos Geo-Arqueológicos, 7 (2010) Geología, aguas, romanos y románico de Tierra de Campos Roca #12;Senderos Geo-Arqueológicos, 7 (2010) Geología, aguas, romanos y románico en Tierra de Campos agua caudalosos que provenientes de la Cordillera Cantábrica, con sus importantes precipitaciones

Fitze, Patrick


Tratamento de águas residuárias: uma proposta para a sustentabilidade ambiental  

Microsoft Academic Search

RESUMO Neste trabalho foi estudado o desempenho de quatro sistemas de pós-tratamento de esgoto sanitário, operados com efluente proveniente de reator UASB. O eixo norteador do trabalho esteve diretamente direcionado para avaliar a remoção de nutrientes, organismos patogênicos e material carbonáceo. O processo de monitoramento teve duração média de 12 meses e o objetivo principal era produzir efluente para aplicação

José Tavares de Sousa; Israel Nunes Henrique; Valderi Duarte Leite; Wilton Silva Lopes



Variación mensual en el aporte de hojas de cuatro especies forestales nativas del Parque Chaqueño Húmedo (Argentina) Monthly variation of the litterfall in four forestal native species from the Humid  

Microsoft Academic Search

El objetivo del trabajo fue cuantificar la cantidad anual de hojas aportadas al suelo proveniente de cuatro especies forestales nativas del Parque Chaqueño Húmedo, y su relación con algunos elementos del clima, como precipitaciones, temperaturas mínimas mensuales, velocidad del viento, heliofanía relativa. Se ubicaron 5 parcelas de 1000 m 2 cada una y se seleccionaron cuatro especies forestales de importancia

J. Prause; G. Arce de Caram; P. N. Angeloni




Microsoft Academic Search

RESUMO: Com o objetivo de se estudar as características tecnológicas da fibra, inclusive a fiabilidade de cultivares de algodão herbáceo (Gossypium hirsutum L. r. latifolium Hutch) cultivadas nos países do Mercosul, um ensaio internacional foi instalado no município de Ipanguaçu, RN, em 199.8, envolvendo dez cultivares provenientes da Argentina, Brasil, Bolívia e Paraguai. Quatorze características da fibra foram investigadas, sendo



Características de Carcaça e do Couro de Bovinos Precoces e Superprecoces  

Microsoft Academic Search

6 Mestrando do Programa de Pós-graduação em Zootecnia - UESB\\/Itapetinga. Bolsista CNPq. Resumo : Objetivou-se avaliar o efeito do sistema de produ ção sobre características produtivas e do couro de bovinos cruzados precoces e superprecoces. Foram utilizados 36 animais, sendo 16 provenientes do sistema superprecoce (10 machos castrados e seis fêmeas), terminados em confinamento e 20 animais do sistema precoce

Luis Carlos Vinhas Ítavo; Fabio Candal Gomes; Manuel Antônio Chagas Jacinto; Celeste Brandão; Ferreira Ítavo; Liliane Suguisawa; Alex Resende; Pesquisador Embrapa; Gado de Corte


Evoluzione della vegetazione nei pressi del Lago di Lavarone (TN) negli ultimi 2200 anni  

Microsoft Academic Search

RIASSUNTO - Evoluzione della vegetazione nei pressi del Lago di Lavarone (TN) negli ultimi 2200 anni - Lo studio pollinico e paleolimnologico della sequenza S5 proveniente dal Lago di Lavarone, condotto nel corso del progetto OLOAMBIENT, ha permesso di ottenere un quadro dettagliato sull'evoluzione del territorio nei pressi del lago negli ultimi 2200 anni. Sulla base delle informazioni archeologiche e

Enrico ARPENTI; Maria Letizia FILIPPI


ISSN n 1676-7748 REVISTA MAGIS  

E-print Network

os interessados numa primeira aproximação com este tema complexo, permitindo na seqüência, outros instrumentos de sua catolicidade medie- val proveniente de Portugal, numa forma de brícolage - suas crenças e


Briófitas do Espírito Santo existentes no Herbário Científico do Estado \\  

Microsoft Academic Search

RESUMO: Estão sendo referidas as briófitas provenientes do estado do Espírito Santo, depositadas no herbário SP. Foram encontradas 265 espécies de briófitas, sendo 147 musgos, 115 hepáticas e 3 antóceros, distribuídas em 63 famílias e 128 gêneros. Destas, 83 espécies são ocorrências novas para o estado (55 musgos, 26 hepáticas e 2 antóceros) e Racomitrium microcarpon (Hedw.) Brid., é uma

Olga Yano; Denilson F. Peralta



E-print Network ABSTRACT We compared levels of DDE contamination in the eggs of burrowing owls (Athene cunicularia) from huevos del bu´ho machuelo excavador (Athene cunicularia) provenientes del Imperial Valley de California local de contaminante para esta poblacio´n residente de bu´hos. Burrowing owls (Athene cunicularia) fre

Gervais, Jennifer


Efeitos da monensina sobre a fermentação e sensibilidade de bactérias ruminais de bovinos sob dietas ricas em volumoso ou concentrado  

Microsoft Academic Search

RESUMO - Objetivou-se avaliar os efeitos da monensina sobre as mudanças nos padrões de fermentação e resistência à perda do potássio intracelular das bactérias ruminais provenientes de quatro bovinos recebendo dietas ricas em volumoso ou concentrado. As bactérias obtidas por centrifugação diferencial foram resuspensas em um meio pobre em potássio, no qual foi medida a perda do p otássio intracelular,

Rogério de Paula Lana; James B. Russell



Una Evaluación Geográfica de la Política de Educación Media Superior de la Ciudad de México  

Microsoft Academic Search

En este trabajo presentamos una evaluación geográfica de la política de las preparatorias creadas y administradas por el gobierno de la ciudad de México. La revisión teórica y evaluación estadística realizadas nos ha permitido (1) construir relaciones explicativas útiles entre varios conceptos de teorías urbanas provenientes de escuelas divergentes, y de disciplinas diferentes, y a la vez (2) hacer una




Futuro de las telecomunicaciones en México ¿Cuál debe ser el rol del gobierno ante los nuevos escenarios del mercado?  

Microsoft Academic Search

El objetivo del presente artículo es analizar las decisiones de política pública que está llevando a cabo el gobierno de México para impulsar la competencia en el mercado de telecomunicaciones. Para ello, se identifica la forma en la que está organizado este sector y se utilizan herramientas provenientes de la teoría económica de redes para evaluar las acciones de este

Fernando G. Toriz Flores



Energy impact of various inside air temperatures and humidities in a museum when located in five U. S. cities  

SciTech Connect

The art conservation literature presents a wide range of recommended temperatures and relative humidities required to protect the safety of collections in museums, but the operating energy costs for specific criteria have not been identified. The Scott Gallery at the Huntington Library and Art Gallery in San Marino, CA, was selected for a detailed study of energy costs associated with recommended environmental levels for museums. The results of computer simulations of the Scott Gallery when located in Albuquerque, NM; Burbank, CA; Minneapolis, MN; New Orleans, LA; and New York, NY are presented. The simulations were performed suing the DOE-2 building energy analysis computer program. The peak heating and cooling load components are identified, thermal zone loads quantified, and psychrometric analysis of the annual energy requirements with fixed and variable inside air temperature and relative humidity (RH) setpoints are presented. In all five climate regions the minimum energy consumption occurred with a 70 {degree} F and 50% RH setpoint.

Ayres, J.M.; Lau, H.; Haiad, J.C. (Ayres Ezer Lau Inc., Los Angeles, CA (US))



210Po Log-normal distribution in human urines: Survey from Central Italy people  

PubMed Central

The death in London of the former secret service agent Alexander Livtinenko on 23 November 2006 generally attracted the attention of the public to the rather unknown radionuclide 210Po. This paper presents the results of a monitoring programme of 210Po background levels in the urines of noncontaminated people living in Central Italy (near the Republic of S. Marino). The relationship between age, sex, years of smoking, number of cigarettes per day, and 210Po concentration was also studied. The results indicated that the urinary 210Po concentration follows a surprisingly perfect Log-normal distribution. Log 210Po concentrations were positively correlated to age (p < 0.0001), number of daily smoked cigarettes (p = 0.006), and years of smoking (p = 0.021), and associated to sex (p = 0.019). Consequently, this study provides upper reference limits for each sub-group identified by significantly predictive variables. PMID:19750019

Sisti, D.; Rocchi, M. B. L.; Meli, M. A.; Desideri, D.



Exact Slope and Interpolating Functions in N=6 Supersymmetric Chern-Simons Theory  

NASA Astrophysics Data System (ADS)

Using the quantum spectral curve approach we compute, exactly, an observable (called slope function) in the planar Aharony-Bergman-Jafferis-Maldacena theory in terms of an unknown interpolating function h(?) which plays the role of the coupling in any integrability based calculation in this theory. We verified our results with known weak coupling expansion in the gauge theory and with the results of semiclassical string calculations. Quite surprisingly at strong coupling the result is given by an explicit rational function of h(?) to all orders. By comparing the structure of our result with that of an exact localization based calculation for a similar observable in Marino and Putrov [J. High Energy Phys. 06 (2010) 011], we conjecture an exact expression for h(?).

Gromov, Nikolay; Sizov, Grigory



La corrosin es un problema permanente en la economa y la industria en general, y en particular, en el entorno ambiental: agua, suelo y atmsfera. Los contaminantes  

E-print Network

particular, en el entorno ambiental: agua, suelo y atmósfera. Los contaminantes provenientes de las descargas humana, alteran la vida acuática y la propia calidad del agua. El control de la corrosión contribuye petroquímica, marítima, vehicular y aeroespacial; agua y energía, incluyendo energías renovables, en diversas


Prevalencia de deficiencia subclínica de vitamina A y desnutrición en niños marginales de Maracaibo - Venezuela  

Microsoft Academic Search

RESUMEN. El presente estudio fue realizado para estimar la prevalencia de deficiencia de vitamina A en niños, mediante examen clínico, oftalmológico y por citología de impresión conjuntival (CIC); y el estado nutricional, analizando los indicadores antropométricos T\\/\\/E, P\\/\\/E y P\\/\\/T. La población de estudio incluyó 157 niños, 2-6 años de edad, provenientes de barrios marginales urbanos y rurales de Maracaibo,

Haydée V. Castejón; Pablo Ortega; María E. Díaz; Daisy Amaya; Gisela Gómez; María Ramos; María V. Alvarado; Jesús R. Urrieta


Elementos de apoio `as aulas de Detecc~ao Remota ISA Primeiro Ciclo  

E-print Network

. O sinal detectado pelo sensor pode ser devido a energia ­ de origem solar ou proveniente de um´etica As observa¸c~oes por detec~ao remota implicam algum tipo de transmiss~ao de energia entre o alvo e o sensor emissor artificial ­ reflectida pela superf´icie ou energia emitida pela pr´opria superf´icie. Em geral


What is 4-H? (Spanish)  

E-print Network

18 U.S.C. 707 4-H 3-5.201S 4/05 4-H es el programa para el desarrollo de la juventud del Servicio de Extensi?n Cooperativa. Se enfoca en las necesidades, preocupaciones e intereses de la gente joven. Su objetivo es ayudar a los j?venes a... planificados, los miembros desarrollan habilidades nuevas, aprenden a cooperar, desarrollan capacidades de liderazgo, mejoran su patriotismo/civismo y se divierten. ?Qu? es 4-H? Los j?venes provenientes de cualquier grupo ?tnico o cultural pueden participar...

Howard, Jeff W.



Safe Operation of Backup Power Generators (Spanish)  

E-print Network

E-395S 04/06 Los generadores port?tiles de electricidad son ?tiles cuando se necesita energ?a el?ctrica provisionalmente o en un sitio remoto, pero los mismos tambi?n pueden causar la muerte. Los peligros principales que se deben evitar al usar... un generador son el envenenamiento por mon?xido de carbono (CO) proveniente de los gases emitidos por el generador, la electrocuci?n y los incendios. Peligros del mon?xido de carbono El mon?xido de carbono es un subproducto sin olor ni color del...

Smith, David



Origen y evolución de la estructura del Universo  

NASA Astrophysics Data System (ADS)

Se presenta una revisión de diversos tópicos vinculados a la evolución de estructuras en el Universo y se discuten los escenarios más aceptados para la comprensión de las irregularidades primigenias y de su evolución temporal. Se analizan evidencias observacionales de la naturaleza jerárquica en los mecanismos de formación de sistemas, tales como las indicaciones provenientes de las correlaciones espaciales y de velocidades, la naturaleza del Universo a alto redshift, y la habilidad de los modelos jerárquicos en predecir diversas propiedades dinámicas, fotométricas y químicas de las galaxias.

García Lambas, D.


Feasibility study of a layer-oriented wavefront sensor for solar telescopes: comment.  


The future generation of telescopes will be equipped with multi-conjugate adaptive-optics (MCAO) systems in order to obtain high angular resolution over large fields of view. MCAO comes in two flavors: star- and layer-oriented. Existing solar MCAO systems rely exclusively on the star-oriented approach. Earlier we suggested a method to implement the layer-oriented approach, and in view of recent concerns by Marino and Wöger [Appl. Opt.53, 685 (2014)10.1364/AO.53.000685APOPAI1559-128X], we now explain the proposed scheme in further detail. We note that in any layer-oriented system one sensor is conjugated to the pupil and the others are conjugated to higher altitudes. For the latter, not all the sensing surface is illuminated by the entire field of view. The successful implementation of nighttime layer-oriented systems shows that the field reduction is no crucial limitation. In the solar approach the field reduction is directly noticeable because it causes vignetting of the Shack-Hartmann subaperture images. It can be accounted for by a suitable adjustment of the algorithms to calculate the local wavefront slopes. We discuss a further concern related to the optical layout of a layer-oriented solar system. PMID:25402984

Kellerer, Aglaé



Experimental studies of the direct flexoelectric effect in bone materials  

NASA Astrophysics Data System (ADS)

The piezoelectric effect in biological tissues has been attracting research interest due to the hypothesis that it may behave as a biological transducer, which can convert external stimuli into biologically-recognizable signals capable of controlling growth or resorptive processes. The piezoelectric effect in dried bone materials was first observed in 1957 [1]. A link between the effect and the adaptive response of bone cells was proposed in 1970 [2]. In this paper, we report our recent measurements on the direct flexoelectric effect in bone materials. Our specimens are both dried and wet bones. The origin of both piezoelectricity and flexoelectricity in bone may be ascribed to the crystalline alignment of the micelle of collagen molecules. The Curie group symmetries of the configuration of collagen fibres in the bone texture demonstrate the existence of both effects. However, our experimental results show that the piezoelectric responses in bone materials may be dominated by flexoelectricity at the micro and nano scales. Finally, we propose a link between the flexoelectric effect and bone spur (osteophyte). [1] E. Fukada and I. Yasuda, J. Phys. Soc. Jpn. 12, 1158 (1957). [2] A. Marino and R. Becker, Nature 228, 78 (1970).

Fu, John



An oceanographic context for the foraging ecology of eastern Pacific leatherback turtles: Consequences of ENSO  

NASA Astrophysics Data System (ADS)

We analyzed some of the primary biological and physical dynamics within the eastern Pacific leatherback turtle ( Dermochelys coriacea) migration area in relation to ENSO and leatherback nesting ecology at Parque Nacional Marino Las Baulas (PNMB), Costa Rica. We used data from remote sensing to calculate resource availability via a net primary production (NPP) model, and to analyze the physical dynamics of the migration area via sea surface temperature fronts. Within the migration area, NPP north of 15°S was highly governed by interannual variability as indicated by the Multivariate ENSO Index while south of 15°S, production had a more seasonal signal. Nesting peaks of leatherbacks at PNMB were associated with cool, highly productive La Niña events and with large-scale equatorial phytoplankton blooms encompassing 110°W that were induced by iron enrichment following the termination of El Niño events. Resource availability in the northern migration area (eastern equatorial Pacific) appeared to determine the nesting response for the population at PNMB, Costa Rica. We suggest that ENSO significantly influences the nesting ecology of leatherbacks at PNMB because the majority of the population consists of pelagic foragers that strictly rely on the eastern equatorial Pacific for prey consumption prior to the nesting season. Coastal foragers may be a minority in the population because of high mortality rates associated with coastal gillnet fisheries along Central and South America.

Saba, Vincent S.; Shillinger, George L.; Swithenbank, Alan M.; Block, Barbara A.; Spotila, James R.; Musick, John A.; Paladino, Frank V.



Surface topology of Minibody by selective chemical modifications and mass spectrometry.  

PubMed Central

The surface topology of the Minibody, a small de novo-designed beta-protein, has been probed by a strategy that combines selective chemical modification with a variety of reagents and mass spectrometric analysis of the modified fragments. Under appropriate conditions, the susceptibility of individual residues primarily depends on their surface accessibility so that their relative reactivities can be correlated with their position in the tertiary structure of the protein. Moreover, this approach provides information on interacting residues, since intramolecular interactions might greatly affect the reactivity of individual side chains by altering their pKa values. The results of this study indicate that, while overall the Minibody model is correct, the beta-sheet formed by the N- and C-terminal segments is most likely distorted. This is also in agreement with previous results that were obtained using a similar approach where mass spectrometry was used to identify Minibody fragments from limited proteolysis (Zappacosta F, Pessi A, Bianchi E, Venturini S, Sollazzo M, Tramontano A. Marino G, Pucci P. 1996. Probing the tertiary structure of proteins by limited proteolysis and mass spectrometry: The case of Minibody. Protein Sci 5:802-813). The chemical modification approach, in combination with limited proteolysis procedures, can provide useful, albeit partial, structural information to complement simulation techniques. This is especially valuable when, as in the Minibody case, an NMR and/or X-ray structure cannot be obtained due to insufficient solubility of the molecule. PMID:9300490

Zappacosta, F.; Ingallinella, P.; Scaloni, A.; Pessi, A.; Bianchi, E.; Sollazzo, M.; Tramontano, A.; Marino, G.; Pucci, P.



In vitro susceptibility testing of Mycobacterium tuberculosis complex strains isolated from seals to antituberculosis drugs.  


Mycobacteria strains belonging to the Mycobacterium tuberculosis complex were isolated from seals found in the South Atlantic. The animals were received in Mundo Marino installations and treated for Mycobacterium tuberculosis complex by conventional therapy of intensive care and enriched food supply; however, in all cases treatment failed. Necropsies of all animals revealed extensive lesions compatible with tuberculosis involving lungs, liver, spleen and lymphatic nodes. Classical biochemical methods as well as molecular techniques using the IS6110 probes were performed for mycobacterial identification. Furthermore, the LCx M. tuberculosis assay (Abbott Laboratories) identified all strains as Mycobacterium tuberculosis complex members. The in vitro susceptibility pattern was examined in mycobacterial strains isolated from seven seals and in 3 reference strains--BCG, H37Rv (M. tuberculosis) and AN5 (Mycobacterium bovis)--to 4 medications--isoniazid, rifampin, streptomycin and ethambutol. Minimal inhibitory drug concentrations were determined by the Mycobacterial Growth Indicator Tube (BD Argentina) method and a microdilution and colorimetric assay using 3-(4-5 dimethyltiazol-2)-2,5 diphenyltetrazolium bromide. All the isolates and the reference strains BCG and AN5 were inhibited by MIC values similar to those of H37Rv with good agreement obtained by both techniques. These findings suggest that a therapeutic regimen aimed to seals diagnosed with tuberculosis play an important role in the prevention of tuberculosis transmission from infected animals to humans that are in routine contact with them. PMID:15495576

Bernardelli, Amelia; Morcillo, Nora; Loureiro, Julio; Quse, Viviana; Davenport, Silvana



Marine hydrogeology: recent accomplishments and future opportunities  

NASA Astrophysics Data System (ADS)

Marine hydrogeology is a broad-ranging scientific discipline involving the exploration of fluid-rock interactions below the seafloor. Studies have been conducted at seafloor spreading centers, mid-plate locations, and in plate- and continental-margin environments. Although many seafloor locations are remote, there are aspects of marine systems that make them uniquely suited for hydrologic analysis. Newly developed tools and techniques, and the establishment of several multidisciplinary programs for oceanographic exploration, have helped to push marine hydrogeology forward over the last several decades. Most marine hydrogeologic work has focused on measurement or estimation of hydrogeologic properties within the shallow subsurface, but additional work has emphasized measurements of local and global fluxes, fluid source and sink terms, and quantitative links between hydrogeologic, chemical, tectonic, biological, and geophysical processes. In addition to summarizing selected results from a small number of case studies, this paper includes a description of several new experiments and programs that will provide outstanding opportunities to address fundamental hydrogeologic questions within the seafloor during the next 20-30 years. L'hydrogéologie marine est une large discipline scientifique impliquant l' exploration des interactions entre les fluides et les roches sous les fonds marins. Des études ont été menées dans les différents environnements sous-marins (zone abyssale, plaque océanique, marges continentales). Bien que de nombreux fonds marins soient connus, il existe des aspects des systèmes marins qui les rendent inadaptés à l'analyse hydrologique. De nouveaux outils et techniques, et la mise en oeuvre de nombreux programmes multidisciplinaires d'exploration océanographique, ont aidé à pousser en avant l'hydrogéologie marine ces dix dernières années. La plus part des études hydrogéologiques se sont concentrées jusqu'à présent sur la mesure ou l'estimation des propriétés à la sub-surface des fonds marins, et des travaux complémentaires ont mis en valeur les mesures de flux, local ou global, de termes « sources » et « pertes », et des liens quantitatifs entre l'hydrogéologie, la chimie, la tectonique, la biologie, et les processus géophysiques. Cet article vise à résumer des résultats sélectionnés parmi un petit nombre d'études, et à décrire plusieurs nouvelles expériences et programmes, qui sont autant d'opportunités pour répondre aux questions fondamentales relatives aux fonds marins, posées ces dernières 20-30 années. La hidrogeología marina es una disciplina científica de amplios alcances que involucra la exploración de interacciones fluido-roca por debajo del fondo del mar. Se han llevado a cabo estudios en centros de expansión del fondo del mar, lugares en medio de una placa, y en ambientes de placa y margen continental. Aunque muchos sitios en el fondo del mar son remotos, existen aspectos de estos sistemas marinos que los hacen particularmente adaptables para análisis hidrológico. Nuevas técnicas y herramientas desarrolladas, y el establecimiento de varios programas multidisciplinarios para exploración oceanográfica, han ayudado a impulsar la hidrogeología marina hacia delante durante las ultimas décadas. La mayor parte del trabajo hidrogeológico marino se ha enfocado en la medición o estimación de propiedades hidrogeológicas dentro del subsuelo superficial, pero trabajo adicionalha enfatizado mediciones de flujos globales y locales, términos de fuente y sumidero de fluidos, y vínculos cuantitativos entre procesos hidrogeológicos, químicos, tectónicos, biológicos y geofísicos. Además de resumir resultados seleccionados de un número pequeño de estudios de caso, este artículo incluye una descripción de varios programas y experimentos nuevos que aportarán oportunidades excepcionales para dirigir preguntas hidrogeológicas fundamentales dentro del fondo oceánico durante los siguientes 20-30 años.

Fisher, A. T.



Global Analysis of Anthropogenic Debris Ingestion by Sea Turtles  

PubMed Central

Ingestion of marine debris can have lethal and sublethal effects on sea turtles and other wildlife. Although researchers have reported on ingestion of anthropogenic debris by marine turtles and implied incidences of debris ingestion have increased over time, there has not been a global synthesis of the phenomenon since 1985. Thus, we analyzed 37 studies published from 1985 to 2012 that report on data collected from before 1900 through 2011. Specifically, we investigated whether ingestion prevalence has changed over time, what types of debris are most commonly ingested, the geographic distribution of debris ingestion by marine turtles relative to global debris distribution, and which species and life-history stages are most likely to ingest debris. The probability of green (Chelonia mydas) and leatherback turtles (Dermochelys coriacea) ingesting debris increased significantly over time, and plastic was the most commonly ingested debris. Turtles in nearly all regions studied ingest debris, but the probability of ingestion was not related to modeled debris densities. Furthermore, smaller, oceanic-stage turtles were more likely to ingest debris than coastal foragers, whereas carnivorous species were less likely to ingest debris than herbivores or gelatinovores. Our results indicate oceanic leatherback turtles and green turtles are at the greatest risk of both lethal and sublethal effects from ingested marine debris. To reduce this risk, anthropogenic debris must be managed at a global level. Análisis Global de la Ingesta de Residuos Antropogénicos por Tortugas Marinas La ingesta de residuos marinos puede tener efectos letales y subletales sobre las tortugas marinas y otros animales. Aunque hay investigadores que han reportado la ingesta de residuos antropogénicos por tortugas marinas y la incidencia de la ingesta de residuos ha incrementado con el tiempo, no ha habido una síntesis global del fenómeno desde 1985. Por esto analizamos 37 estudios publicados, desde 1985 hasta 2012, que reportan datos colectados desde antes de 1900 y a lo largo del 2011. Investigamos específicamente si el predominio de la ingesta ha cambiado con el tiempo, qué tipos de residuos se ingieren comúnmente, la distribución geográfica de la ingesta de residuos por tortugas marinas en relación a la distribución global de residuos y cuáles especies y etapas de vida tienen más probabilidad de ingerir residuos. La probabilidad de que las tortugas verdes (Chelonia mydas) y laúd (Dermochelys coriacea) ingieran escombros incrementa significativamente con el tiempo; plástico fue el residuo que más se ingirió. Las tortugas en casi todas las regiones estudiadas ingieren residuos, pero la probabilidad de ingesta no estuvo relacionada con las densidades modeladas de residuos. Además de esto, tortugas más pequeñas, en etapa oceánica de vida, tuvieron una mayor probabilidad de ingerir residuos que las tortugas forrajeras terrestres, mientras que las especies carnívoras tuvieron menos probabilidad de ingerir residuos que las herbívoras o las gelatinívoras. Nuestros resultados indican que las tortugas verdes y laúd tienen el mayor riesgo de efectos letales y subletales de la ingesta de residuos marinos. Para reducir el riesgo, los residuos antropogénicos deben manejarse en un nivel global. PMID:23914794

Schuyler, Qamar; Hardesty, Britta Denise; Wilcox, Chris; Townsend, Kathy



Effects of illegal harvest of eggs on the population decline of leatherback turtles in Las Baulas Marine National Park, Costa Rica.  


Within 19 years the nesting population of leatherback turtles (Dermochelys coriacea) at Parque Nacional Marino Las Baulas declined from 1500 turtles nesting per year to about 100. We analyzed the effects of fishery bycatch and illegal harvesting (poaching) of eggs on this population. We modeled the population response to different levels of egg harvest (90, 75, 50, and 25%) and the effect of eradicating poaching at different times during the population decline. We compared effects of 90% poaching with those of 20% adult mortality because both of these processes were present in the population at Las Baulas. There was a stepwise decline in number of nesting turtles at all levels of egg harvest. Extirpation times for different levels of poaching ranged from 45 to 282 years. The nesting population declined more slowly and survived longer with 20% adult mortality (146 years) than it did with 90% poaching (45 years). Time that elapsed until poaching stopped determined the average population size at which the population stabilized, ranging from 90 to 420 nesting turtles. Our model predicted that saving clutches lost naturally would restore the population when adult mortality rates were low and would contribute more to population recovery when there were short remigration intervals between nesting seasons and a large proportion of natural loss of clutches. Because the model indicated that poaching was the most important cause of the leatherback decline at Las Baulas, protecting nests on the beach and protecting the beach from development are critical for survival of this population. Nevertheless, the model predicted that current high mortality rates of adults will prevent population recovery. Therefore, protection of the beach habitat and nests must be continued and fishery bycatch must be reduced to save this population. PMID:18637915

Tomillo, Pilar Santidrián; Saba, Vincent S; Piedra, Rotney; Paladino, Frank V; Spotila, James R



The game of active search for extra-terrestrial intelligence: breaking the `Great Silence'  

NASA Astrophysics Data System (ADS)

The search for extra-terrestrial intelligence (SETI) has been performed principally as a one-way survey, listening of radio frequencies across the Milky Way and other galaxies. However, scientists have engaged in an active messaging only rarely. This suggests the simple rationale that if other civilizations exist and take a similar approach to ours, namely listening but not broadcasting, the result is a silent universe. A simple game theoretical model, the prisoner's dilemma, explains this situation: each player (civilization) can passively search (defect), or actively search and broadcast (cooperate). In order to maximize the payoff (or, equivalently, minimize the risks) the best strategy is not to broadcast. In fact, the active search has been opposed on the basis that it might be dangerous to expose ourselves. However, most of these ideas have not been based on objective arguments, and ignore accounting of the possible gains and losses. Thus, the question stands: should we perform an active search? I develop a game-theoretical framework where civilizations can be of different types, and explicitly apply it to a situation where societies are either interested in establishing a two-way communication or belligerent and in urge to exploit ours. The framework gives a quantitative solution (a mixed-strategy), which is how frequent we should perform the active SETI. This frequency is roughly proportional to the inverse of the risk, and can be extremely small. However, given the immense amount of stars being scanned, it supports active SETI. The model is compared with simulations, and the possible actions are evaluated through the San Marino scale, measuring the risks of messaging.

de Vladar, Harold P.



Climate change, marine environments, and the US Endangered species act.  


Climate change is expected to be a top driver of global biodiversity loss in the 21st century. It poses new challenges to conserving and managing imperiled species, particularly in marine and estuarine ecosystems. The use of climate-related science in statutorily driven species management, such as under the U.S. Endangered Species Act (ESA), is in its early stages. This article provides an overview of ESA processes, with emphasis on the mandate to the National Marine Fisheries Service (NMFS) to manage listed marine, estuarine, and anadromous species. Although the ESA is specific to the United States, its requirements are broadly relevant to conservation planning. Under the ESA, species, subspecies, and "distinct population segments" may be listed as either endangered or threatened, and taking of most listed species (harassing, harming, pursuing, wounding, killing, or capturing) is prohibited unless specifically authorized via a case-by-case permit process. Government agencies, in addition to avoiding take, must ensure that actions they fund, authorize, or conduct are not likely to jeopardize a listed species' continued existence or adversely affect designated critical habitat. Decisions for which climate change is likely to be a key factor include: determining whether a species should be listed under the ESA, designating critical habitat areas, developing species recovery plans, and predicting whether effects of proposed human activities will be compatible with ESA-listed species' survival and recovery. Scientific analyses that underlie these critical conservation decisions include risk assessment, long-term recovery planning, defining environmental baselines, predicting distribution, and defining appropriate temporal and spatial scales. Although specific guidance is still evolving, it is clear that the unprecedented changes in global ecosystems brought about by climate change necessitate new information and approaches to conservation of imperiled species. El Cambio Climático, los Ecosistemas Marinos y el Acta Estadunidense de Especies en Peligro. PMID:24299080

Seney, Erin E; Rowland, Melanie J; Lowery, Ruth Ann; Griffis, Roger B; McClure, Michelle M



Um supressor de fundo térmico para a câmara infravermelha CamIV  

NASA Astrophysics Data System (ADS)

O ângulo sólido subtendido pelos pixels na câmara infravermelha do NexGal (CamIV) que operamos no OPD/LNA contém contribuições provenientes do sistema de coleta de fluxo propriamente dito - sendo esta a parte que interessa para as medidas astronômicas - e contribuições da obstrução central, sistema de suporte do espelho secundário e região exterior à pupila de entrada do telescópio. Estas últimas contribuições são devi-das à emissão de corpo negro à temperatura ambiente e aumentam exponencialmente para comprimentos de onda maiores que 2 micra (banda K, no infravermelho próximo). Embora a resultante pode ser quantificada e subtraída dos sinais relevantes, sua variância se adiciona à variância do sinal, e pode ser facilmente a contribuição domi-nante para a incerteza final das medidas, tornando ineficiente o processo de extração de informação e degradando a sensibilidade da câmara. A maneira clássica de resolver esse problema em sistemas ópticos que operam no infravermelho, onde os efeitos da emissão térmica do ambiente são importantes, é restringir o ângulo sólido subtendido pelos pixels individuais exclusivamente aos raios provenientes do sistema óptico. Para tanto, projeta-se uma imagem real, bastante reduzida, da pupila de entrada do sistema óptico num anteparo que transmita para o sistema de imageamento só o que interessa, bloqueando as contribuições das bordas externas à pupila de entrada, obstrução central do telescópio e sistema de suporte. Como a projeção é realizada em ambiente criogênico, a contribuição térmica espúria é efetivamente eliminada. Nós optamos por um sistema do tipo Offner para implementar na prática esta função. Trata-se de um sistema baseado em espelhos esféricos, bastante compacto e ajustado por construção. A opção por espelhos do mesmo material que o sistema de suporte (Alumínio) minimiza a dilatação diferencial, crítica nesse tipo de aplicação. Apresentamos as soluções detalhadas do projeto óptico-mecânico, bem como uma análise de flexões e desempenho em termos de qualidade de imagem.

Jablonski, F.; Laporte, R.



Experimental simulation of gravity currents in erodible bed  

NASA Astrophysics Data System (ADS)

Gravity currents are commonly met in nature, when a flow of denser fluid moves into a less dense one. A typical example of a gravity current is given by the sea water which flows into the bottom of a river during the summer, in correspondence of the estuary, when the river's discharge attains low values. In this case, dangerous consequences can occur, because of the polluting of the aquifer caused by the salty water. Density currents also occurs in lakes and reservoirs, because of a change in temperature or because a flood, both can produce some environmental impacts that are of interest to the local water Agency of the different countries. Of particular relevance is also the interaction of the gravity current with the movement of the sediments from the bottom of the bed. The international state of the art is particularly concerned with experimental and numerical investigation on gravity currents on fixed and porous bed [1-2-3], while, to the authors' knowledge, the interaction of a gravity current with an erodible bed is still an open field of investigation. In this paper experiments concerning with the propagation of a gravity current over fixed and erodible bed are presented. The experiments, conducted at the laboratory of Hydraulics of the Universitat Politecnica de Catalunya (actually in the Prof. Bateman's blue room), were concerned with a transparent tank 2 m long, 0.2 m wide and 0.3 m deep, partly filled with salty water and partly with fresh water, up to a depth of 0.28 m. The salty water, whose density was in the range 1050Marino, P.F. Linden, Lock-release inertial gravity currents over a thick porous layer, The Journal of Fluid Mechanics, Vol. 503, 2004 [2] John E. Simpson. Gravity Currents [3] J.J. Monaghan, R.A.F. Cas, A.M. Kos, M. Hallworth, Gravity currents descending a ramp in a stratified tank, The Journal of Fluid Mechanics, Vol. 379, 1999

Bateman, A.; La Roca, M.; Medina, V.



The Roles of Dopamine Transport Inhibition and Dopamine Release Facilitation in Wake Enhancement and Rebound Hypersomnolence Induced by Dopaminergic Agents  

PubMed Central

Study Objective: Rebound hypersomnolence (RHS: increased sleep following increased wake) is a limiting side-effect of many wake-promoting agents. In particular, RHS in the first few hours following wake appears to be associated with dopamine (DA)-releasing agents, e.g., amphetamine, but whether it can also be produced by DA transporter (DAT) inhibition alone is unknown. In these studies, DA-releasing and DAT-inhibiting agents and their interaction were systematically examined for their ability to increase wake and induce RHS. Design: Chronically implanted rats were evaluated in a blinded, pseudo-randomized design. Participants: 237 rats were used in these studies with 1 week between repeat tests. Interventions: Animals were habituated overnight and dosed the next day, 5 h after lights on, with test agents. Measurements and Results: Sleep/wake activity and RHS were evaluated using EEG/EMG recording up to 22 h post dosing. In vitro dopamine release was evaluated in rat synaptosomes. At doses that produced equal increases in wake, DA-releasing (amphetamine, methamphetamine, phentermine) and several DAT-inhibiting agents (cocaine, bupropion, and methylphenidate) produced RHS during the first few hours after the onset of sleep recovery. However, other DAT-inhibiting agents (mazindol, nomifensine, GBR-12909, and GBR-12935) did not produce RHS. Combination treatment with amphetamine and nomifensine produced waking activity greater than the sum of their individual activities alone while ameliorating the amphetamine-like RHS. In rat synaptosomes, nomifensine reduced the potency of amphetamine to induce DA release ?270-fold, potentially explaining its action in ameliorating amphetamine-induced RHS. Conclusions: All DA releasing agents tested, and some DAT-inhibiting agents, produced RHS at equal wake-promoting doses. Thus amphetamine-like DA release appears sufficient for inducing RHS, but additional properties (pharmacologic and/or pharmacokinetic) evidently underlie RHS of other DAT inhibitors. Enhancing wake while mitigating RHS can be achieved by combining DAT-inhibiting and DA-releasing agents. Citation: Gruner JA; Marcy VR; LinYG; Bozyczko-Coyne D; Marino MJ; Gasior M. The roles of dopamine transport inhibition and dopamine release facilitation in wake enhancement and rebound hypersomnolence induced by dopaminergic agents. SLEEP 2009;32(11):1425-1438. PMID:19928382

Gruner, John A.; Marcy, Val R.; Lin, Yin-Guo; Bozyczko-Coyne, Donna; Marino, Michael J.; Gasior, Maciej



Very Low-Mass Stars and Brown Dwarfs  

NASA Astrophysics Data System (ADS)

Part I. Searches in Clusters, Stellar Associations and the Field: 1. Open clusters after HIPPARCOS J. S. Mermilliod; 2. Proper motions of very low mass stars and brown dwarfs in open clusters N. C. Hambly; 3. Parallaxes for brown dwarfs in clusters C. G. Tinney; 4. Very low mass stars and brown dwarfs in the Belt of Orion S. J. Wolk and F. M. Walter; 5. Photometric surveys in open clusters M. R. Zapatero Osorio; 6. The mass function of the Pleiades R. F. Jameson et al.; 7. Brown dwarfs and the low-mass initial mass function in young clusters K. L. Luhman; 8. Very low mass stars in globular clusters I. R. King and G. Piotto; 9. The DENIS very low mass star and brown dwarf results X. Delfosse and T. Forveille; 10. Preliminary results from the 2MASS core project J. Liebert et al.; Part II. Spectroscopic Properties, Fundamental Parameters and Modelling: 11. Properties of M dwarfs in clusters and the field S. L. Hawley et al.; 12. Spectroscopy of very low mass stars and brown dwarfs in young clusters E. L. Martin; 13. High resolution spectra of L type stars and brown dwarfs G. Basri et al.; 14. Modelling very low mass stars and brown dwarf atmospheres F. Allard; 15. Dust in very cool dwarfs T. Tsuji; 16. On the interpretation of the optical spectra of very cool dwarfs Ya. V. Pavlenko; 17. Absolute dimensions for M type dwarfs A. Gimenez; 18. Theory of very low mass stars and brown dwarfs I. Baraffe; Part III. Convection, Rotation and Acitivity: 19. Convection in low mass stars F. D'Antona; 20. Rotation law and magnetic field in M dwarf models G. Rudiger and M. Kuker; 21. Doppler imaging of cool dwarf stars K. G. Strassmeier; 22. X-ray Emission from cool dwarfs in clusters S. Randich; 23. X-ray variability for dM stars G. Micela and A. Marino; 24. The coronae of AD Leo and EV Lac S. Sciortino et al.; 25. Prospects of vuture X-ray missions for low mass stars and cluster stars R. Pallavicini.

Rebolo, Rafael; Rosa Zapatero-Osorio, Maria



Measuring Sleep: Accuracy, Sensitivity, and Specificity of Wrist Actigraphy Compared to Polysomnography  

PubMed Central

Objectives: We validated actigraphy for detecting sleep and wakefulness versus polysomnography (PSG). Design: Actigraphy and polysomnography were simultaneously collected during sleep laboratory admissions. All studies involved 8.5 h time in bed, except for sleep restriction studies. Epochs (30-sec; n = 232,849) were characterized for sensitivity (actigraphy = sleep when PSG = sleep), specificity (actigraphy = wake when PSG = wake), and accuracy (total proportion correct); the amount of wakefulness after sleep onset (WASO) was also assessed. A generalized estimating equation (GEE) model included age, gender, insomnia diagnosis, and daytime/nighttime sleep timing factors. Setting: Controlled sleep laboratory conditions. Participants: Young and older adults, healthy or chronic primary insomniac (PI) patients, and daytime sleep of 23 night-workers (n = 77, age 35.0 ± 12.5, 30F, mean nights = 3.2). Interventions: N/A. Measurements and Results: Overall, sensitivity (0.965) and accuracy (0.863) were high, whereas specificity (0.329) was low; each was only slightly modified by gender, insomnia, day/night sleep timing (magnitude of change < 0.04). Increasing age slightly reduced specificity. Mean WASO/night was 49.1 min by PSG compared to 36.8 min/night by actigraphy (? = 0.81; CI = 0.42, 1.21), unbiased when WASO < 30 min/night, and overestimated when WASO > 30 min/night. Conclusions: This validation quantifies strengths and weaknesses of actigraphy as a tool measuring sleep in clinical and population studies. Overall, the participant-specific accuracy is relatively high, and for most participants, above 80%. We validate this finding across multiple nights and a variety of adults across much of the young to midlife years, in both men and women, in those with and without insomnia, and in 77 participants. We conclude that actigraphy is overall a useful and valid means for estimating total sleep time and wakefulness after sleep onset in field and workplace studies, with some limitations in specificity. Citation: Marino M; Li Y; Rueschman MN; Winkelman JW; Ellenbogen JM; Solet JM; Dulin H; Berkman LF; Buxton OM. Measuring sleep: accuracy, sensitivity, and specificity of wrist actigraphy compared to polysomnography. SLEEP 2013;36(11):1747-1755. PMID:24179309

Marino, Miguel; Li, Yi; Rueschman, Michael N.; Winkelman, J. W.; Ellenbogen, J. M.; Solet, J. M.; Dulin, Hilary; Berkman, Lisa F.; Buxton, Orfeu M.



Aceptabilidad del diagn?stico r?pido casero para HIV entre hombres gay y otros hombres que tienen sexo con hombres (G&HSH) de la Ciudad de Buenos Aires  

PubMed Central

Resumen El uso del diagnóstico rápido para HIV en Argentina, así como otros países de Latinoamérica, ha sido limitado hasta el momento. Este trabajo reporta los resultados provenientes de un estudio cualitativo realizado entre hombres gays y otros hombres que tienen sexo con hombres (G&HSH) de la Ciudad de Buenos Aires, Argentina. El objetivo principal del mismo fue conocer las ventajas y desventajas que los hombres G&HSH perciben en relación al diagnóstico rápido casero para HIV. Se realizaron ocho grupos focales con 73 participantes en los cuales se discutió acerca de las ventajas y desventajas del uso de los diagnósticos rápidos. Las respuestas fueron codificadas utilizando un programa para análisis de datos cualitativos (NVivo) y analizadas temáticamente. Los participantes describieron numerosas ventajas sobre el uso del diagnóstico rápido casero, aunque algunos reportaron importantes preocupaciones dentro de las cuales se destaca la posibilidad de impulsos suicidas si alguien recibe un resultado positivo estando solo. En términos generales se observó una gran aceptabilidad para el uso del diagnóstico rápido si el mismo es realizado por personal de salud en lugares acondicionados para este fin.

Balan, Ivan C.; Carballo-Dieguez, Alex; Marone, Ruben O.; Pando, Maria A.; Barreda, Victoria; Avila, Maria M.



Argumentos Antrópicos  

NASA Astrophysics Data System (ADS)

A existência de observadores é um fato. Este fato, entretanto, permite que possam ser extraídas informações físicas, astrofísicas e cosmológicas. A realidade da existência de observadores foi elevada por Carter [1] ao nível de um princípio, chamado Princípio Antrópico. Em linhas gerais o Princípio Antrópico afirma que a existência de observadores só é possível dentro de certos parâmetros físicos muito restritos. O Princípio Antrópico é uma fonte de compreensão de fatos observáveis do Universo. Na ausência de explicações provenientes das leis da física, as previsões antrópicas tornam-se importantes fatores de esclarecimento. Além disso, o Princípio Antrópico pode ainda atuar como supressor da necessidade de novas teorias. Foi aliás no quadro de discussões em torno da necessidade de novas teorias que o Princípio Antrópico foi concebido, nomeadamente na discussão em torno dos números muito grandes. Para explicar estes grandes números, Dirac [2] formulou uma hipótese inovadora, a de que a constante gravitacional variaria com o tempo na forma 1 - µ G t . Se aceita, tal relação se constituiria numa revisão das leis da física já estabelecida. Daria origem a uma nova física. Entretanto, com a elaboração do Princípio Antrópico por Dicke [3] e Carter [1] a coincidência de tais grandes números foi compreendida dentro da física tradicional, sem a necessidade de recurso a novas leis.

Villas da Rocha, J.F.; Casarejos, F.



Establishing IUCN Red List Criteria for Threatened Ecosystems  

PubMed Central

Abstract The potential for conservation of individual species has been greatly advanced by the International Union for Conservation of Nature's (IUCN) development of objective, repeatable, and transparent criteria for assessing extinction risk that explicitly separate risk assessment from priority setting. At the IV World Conservation Congress in 2008, the process began to develop and implement comparable global standards for ecosystems. A working group established by the IUCN has begun formulating a system of quantitative categories and criteria, analogous to those used for species, for assigning levels of threat to ecosystems at local, regional, and global levels. A final system will require definitions of ecosystems; quantification of ecosystem status; identification of the stages of degradation and loss of ecosystems; proxy measures of risk (criteria); classification thresholds for these criteria; and standardized methods for performing assessments. The system will need to reflect the degree and rate of change in an ecosystem's extent, composition, structure, and function, and have its conceptual roots in ecological theory and empirical research. On the basis of these requirements and the hypothesis that ecosystem risk is a function of the risk of its component species, we propose a set of four criteria: recent declines in distribution or ecological function, historical total loss in distribution or ecological function, small distribution combined with decline, or very small distribution. Most work has focused on terrestrial ecosystems, but comparable thresholds and criteria for freshwater and marine ecosystems are also needed. These are the first steps in an international consultation process that will lead to a unified proposal to be presented at the next World Conservation Congress in 2012. Establecimiento de Criterios para la Lista Roja de UICN de Ecosistemas Amenazados Resumen El potencial para la conservación de muchas especies ha avanzado enormemente porque la Unión Internacional para la Conservación de la Naturaleza (UICN) ha desarrollado criterios objetivos, repetibles y transparentes para evaluar el riesgo de extinción que explícitamente separa la evaluación de riesgo de la definición de prioridades. En el IV Congreso Mundial de Conservación en 2008, el proceso comenzó a desarrollar e implementar estándares globales comparables para ecosistemas. Un grupo de trabajo establecido por la UICN ha formulado un sistema inicial de categorías y criterios cuantitativos, análogos a los utilizados para especies, para asignar niveles de amenaza a ecosistemas a niveles local, regional y global. Un sistema final requerirá de definiciones de ecosistemas; cuantificación del estatus de ecosistemas; identificación de las etapas de degradación y pérdida de los ecosistemas; medidas de riesgo (criterios) alternativas; umbrales de clasificación para esos criterios y métodos estandarizados para la realización de evaluaciones. El sistema deberá reflejar el nivel y tasa de cambio en la extensión, composición, estructura y funcionamiento de un ecosistema, y tener sus raíces conceptuales en la teoría ecológica y la investigación empírica. Sobre la base de esos requerimientos y la hipótesis de que el riesgo del ecosistema es una función del riesgo de las especies que lo componen, proponemos un conjunto de 4 criterios: declinaciones recientes en la distribución o funcionamiento ecológica, pérdida total histórica en la distribución o funcionamiento ecológico, distribución pequeña combinada con declinación, o distribución muy pequeña. La mayor parte del trabajo se ha concentrado en ecosistemas terrestres, pero también se requieren umbrales y criterios comparables para ecosistemas dulceacuícolas y marinos. Estos son los primeros pasos de un proceso de consulta internacional que llevará a una propuesta unificada que será

Rodriguez, Jon Paul; Rodriguez-Clark, Kathryn M; Baillie, Jonathan E M; Ash, Neville; Benson, John; Boucher, Timothy; Brown, Claire; Burgess, Neil D; Collen, Ben; Jennings, Michael; Keith, David A; Nicholson, Emily; Revenga, Carmen; Reyers, Belinda; Rouget, Mathieu; Smith, Tammy; Spalding, Mark; Taber, Andrew; Walpole, Matt; Zager, Irene; Zamin, Tara



INIC11 highlights implementation--Welcome note organizing committee  

PubMed Central

Our keynote addresses our main theme presenting three practical guides on integrated homecare (IHC) from the FP7-Homecare-project for patients suffering from stroke, Heart failure and COPD which together represent a fourth of the economic burden of disease and about every third deaths in the industrialized world. Our fourth keynote exemplifies good organization of integrated care by the German Kinzigtal-project. These themes are expanded in a number of other sessions and posters by other scientists demonstrating a good resonance in the scientific community. After INIC11 we may be close to the ‘critical mass’ of research required to expect a breakthrough in implementation! The broader profile of INIC is continued by a series of other excellent contributions i.e.: Effective collaborative care for depression and anxiety reported by a team from the Netherlands.Special sessions on Telerehabilitation and ‘Social Care Informatics’ present a series of good evidence and strategies on the use of tele-facilities within a framework where the collaborative integration of care—and not IT itself—is the main focus.A workshop on ‘Integrated oncology pathways’ is a joint Danish-Dutch venture.Also, we look forward to present a series of exciting virtual study trips to IC in San Marino (hosting INIC12), Germany, UK, Spain, Portugal, Finland and Italy.The Dutch contribution is as always impressive at INIC11. Participants from many countries may look forward to learn about the results from recent developments in the Dutch system of finance of integrated care to large groups with chronic conditions.Other sessions present specific projects funded by EU. These presentations are followed by a panel discussion on the finance of IC at the final part of INIC11.This year we have had a series of abstracts from projects with clearcut findings or experimental designs opted for poster presentation. The poster section comprises about 30 presentations.For more years experienced IC-scientists including Gus Schrijvers and Nick Goodwin have prepared a special initiative for PhD-students to improve the long-term competencies in the field of IC. We are proud to announce that INIC11 launches a special stream of sessions termed ‘IC-University for PhD-students’ with a focus on methodological issues. Also, we would like to draw your attention to the cultural richness of the town of Odense and the whole region of Funen if you have the opportunity to stay a few extra days. Finally—but not least—I would like to thank Guus, Clarine and Marianne for a wonderful collaboration during the practical preparation of INIC11 and Helmut, Albert, Silvina, Jeroen and Ilmo to complement us with the scientific program.

Larsen, Torben



Chlorine-36 in groundwater of the United States: empirical data  

NASA Astrophysics Data System (ADS)

Natural production of the radionuclide chlorine-36 (36Cl) has provided a valuable tracer for groundwater studies. The nuclear industry, especially the testing of thermonuclear weapons, has also produced large amounts of 36Cl that can be detected in many samples of groundwater. In order to be most useful in hydrologic studies, the natural production prior to 1952 should be distinguished from more recent artificial sources. The object of this study was to reconstruct the probable preanthropogenic levels of 36Cl in groundwater in the United States. Although significant local variations exist, they are superimposed on a broad regional pattern of 36Cl/Cl ratios in the United States. Owing to the influence of atmospherically transported ocean salt, natural ratios of 36Cl/total Cl are lowest near the coast and increase to a maximum in the central Rocky Mountains of the United States. Résumé. La production naturelle du radionucléide chlore-36 (36Cl) fournit un intéressant traceur pour l'étude des eaux souterraines. L'industrie nucléaire, en particulier les essais de bombes thermonucléaires, a également produit de grandes quantités de 36Cl qui a pu être détecté dans de nombreux échantillons d'eau souterraine. Afin d'en améliorer l'usage dans les études hydrologiques, la production naturelle avant 1952 doit être distinguée des sources artificielles plus récentes. L'objectif de cette étude a été la reconstruction des niveaux probables de 36Cl dans les eaux souterraines des États-Unis, avant la production anthropique du 36Cl. Bien qu'il existe des variations locales significatives, elles se surimposent à un canevas régional de rapports 36Cl/Cl dans les États-Unis. Du fait de l'influence du sel océanique transporté dans l'atmosphère, les rapports naturels de 36Cl/Cl total sont plus faibles près de la côte et augmentent jusqu'à un maximum dans les Montagnes Rocheuses centrales des États-Unis. Resumen. La producción natural del radionucleido cloro-36 (36Cl) representa un trazador valioso para estudios de hidrogeología. La industria nuclear, sobretodo por los ensayos con armas nucleares, también ha producido grandes cantidades de 36Cl que pueden ser detectadas en muchas muestras de aguas subterráneas. Para que sean lo más útiles posible en estudios hidrológicos, la producción natural anterior al año 1952 debe ser diferenciada de la procedente de fuentes artificiales más recientes. El objeto de este estudio era la reconstrucción de los niveles probables de 36Cl en las aguas subterráneas de los Estados Unidos de América con anterioridad a las aportaciones de origen antrópico. Aunque existen variaciones locales significativas, éstas se superponen a un extenso patrón regional de la relación 36Cl/Cl en el país. Debido a la influencia de la sal transportada en los aerosoles marinos, las proporciones naturales de 36Cl/Cl total son menores cerca de la costa, y alcanzan su máximo en el centro de las Montañas Rocosas.

Davis, Stanley; Moysey, Stephen; Cecil, DeWayne; Zreda, Marek



Um estudo espectrofotométrico da variável cataclísmica V3885 Sgr  

NASA Astrophysics Data System (ADS)

Variáveis Cataclísmicas são sistemas binários cerrados compostos de uma anã vermelha que transfere matéria para uma anã branca, em sistemas não magnéticos ocorre a formação de um disco de acresção em torno da anã branca. V3885 Sgr é uma variável cataclísmica classificada como sendo do tipo nova-like. É apresentado um estudo espectrofotométrico de V3885 Sgr de alta resolução temporal feito na região do visível. A região observada é centrada em Ha e abrange também a linha de HeI 6678. O primeiro resultado obtido neste estudo é a determinação do período orbital a partir de medidas da velocidade radial da linha de Ha como sendo 0,20716071(22) dias, resolvendo inconsistências quanto a esse valor na literatura e definindo uma efeméride a longo prazo para o sistema. Com este período e as medidas de velocidade radial do perfil de linha de Ha foi construído um diagrama de massas, através do qual restringimos as massas das componentes estelares do sistema e limitamos a inclinação orbital do sistema. Foram construídos diagramas de Greenstein para as linhas de Ha e HeI, onde os espectros médios em cada intervalo de fase são representados lado a lado em escala de cinza, indicando a existência de uma emissão intensa proveniente da parte posterior do disco. A partir da tomografia Doppler obtivemos perfis de emissividade radial para o disco tanto para a linha de Ha como para HeI. Os resultados obtidos são comparados com os de outros sistemas estudados com a mesma técnica. Serão apresentados também resultados da tomografia de flickering para o sistema.

Ribeiro, F. M. A.; Diaz, M. P.



Las fulguraciones como manifestación de reconexión en el campo magnético solar  

NASA Astrophysics Data System (ADS)

Las fulguraciones solares son fenómenos transitorios de liberación de energía que se desarrollan en las estructuras magnéticas de las regiones activas del Sol. Las fulguraciones pueden llegar a liberar hasta 1032 erg en 100 seg. en todo el rango electromagnético, y acelerar partículas. En este trabajo mostramos que la ubicación de los abrillantamientos en H? de diversas fulguraciones está relacionado con las propiedades de las conexiones de las líneas del campo magnético de la región, como se espera por las teorías de reconexión en 3D recientemente desarrolladas (Démoulin et al, 1996a). El campo magnético coronal se extrapola del campo fotosférico observado suponiendo una configuración libre de fuerzas lineal. Por medio de un algoritmo se determinan las regiones donde existe un cambio drástico en la conectividad de las líneas de campo (límites ``cuasi-discontinuos'', o cuasi-separatrices CS). Las CS son bandas abiertas que identifican zonas donde el campo magnético se reconectará con más probabilidad y, siempre que las mismas sean lo suficientemente finas, se producirá allíla liberación de energía proveniente del campo magnético. Hemos encontrado que en todas las regiones fulgurantes estudiadas (Démoulin et al, 1996b) existen CS en los mismos lugares donde se observaron los abrillantamientos en H?. Allídonde coinciden los abrillantamientos con las CS, éstas tienen un espesor menor que 1 Mm. Las líneas de campo coronales extrapoladas de nuestro modelo tienen sus orígenes fotosféricos a ambos lados de las CS, como se espera dados los recientes estudios de reconexión magnética en 3D. Estos resultados ponen a prueba los modelos presentes sobre fulguraciones solares.

Bagalá, L. G.; Mandrini, M. C.; Rovira, M. G.; Démoulin, P.


Courtship behavior of different wild strains of Ceratitis Capitata (Diptera: Tephritidae)  

SciTech Connect

This study documents differences in the courtship behavior of wild strains of Ceratitis capitata (Wiedemann) from Madeira (Portugal), Hawaii (U.S.A.), Costa Rica, and Patagonia (Argentina). Some traits showed large variations and others substantial overlaps. The angle at which the male faced toward the female at the moment of transition from continuous wing vibration and intermittent buzzing changed very little during the course of courtship in all strains, but males from Madeira tended to face more directly toward the female than other males. Females tended to look more, and more directly, toward the males as courtship progressed in all strains. The distance between male and female tended to decrease as courtship proceeded in all strains, but the distances at which males initiated continuous vibration, intermittent buzzing, and jumped onto the female were relatively less variable between strains, except for the strain from Costa Rica. Flies of Madeira courted for longer and the male moved his head and buzzed his wings longer than the other strains. (author) [Spanish] Este estudio documenta diferencias en el comportamiento de cortejo de cepas silvestres de Ceratitis capitata (Wied.) provenientes de Madeira (Portugal), Hawaii (Estados Unidos de Norte America), Costa Rica y Patagonia (Argentina). Algunas caracteristicas mostraron grandes variaciones y traslape substancial. Los angulos a los cuales los machos miraron hacia las hembras cambiaron muy poco en el momento de la transicion de la vibracion continua al zumbido intermitente durante el curso del cortejo en todo las cepas, pero los machos de Madeira tendieron a enfrentar mas directamente a la hembra que otros machos. Los angulos de las hembras disminuyeron claramente durante el cortejo en todas las cepas. La distancia entre el macho y la hembra tendio a disminuir conforme el cortejo continuaba en todas las cepas, pero las distancias a las cuales los machos iniciaron la vibracion continua, el zumbido intermitente, y el salto sobre la hembra eran relativamente menos variables entre cepas excepto la cepa de Costa Rica. Moscas de Madeira cortejaron mas tiempo y el macho moviosu cabeza y zumbaba sus alas mas prolongadamente que las otras cepas. (author)

Briceno, D. [Escuela de Biologia, Universidad de Costa Rica, Ciudad Universitaria (Costa Rica); Eberhard, W. [Escuela de Biologia, Universidad de Costa Rica, Ciudad Universitaria and Smithsonian Tropical Research Institute (Costa Rica); Vilardi, J. [Dpto. de Ciencias Biologicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Cayol, J.-P. [Technical Cooperation Division, IAEA, Wagramerstrasse 5, P.O. Box 100 A-1400, Vienna (Austria); Shelly, T. [A. C. , D. , E. USDA/APHIS/CPHST, 41-650 Ahiki St. Waimanalo, HI 96795 (United States)



A thick lens of fresh groundwater in the southern Lihue Basin, Kauai, Hawaii, USA  

NASA Astrophysics Data System (ADS)

A thick lens of fresh groundwater exists in a large region of low permeability in the southern Lihue Basin, Kauai, Hawaii, USA. The conventional conceptual model for groundwater occurrence in Hawaii and other shield-volcano islands does not account for such a thick freshwater lens. In the conventional conceptual model, the lava-flow accumulations of which most shield volcanoes are built form large regions of relatively high permeability and thin freshwater lenses. In the southern Lihue Basin, basin-filling lavas and sediments form a large region of low regional hydraulic conductivity, which, in the moist climate of the basin, is saturated nearly to the land surface and water tables are hundreds of meters above sea level within a few kilometers from the coast. Such high water levels in shield-volcano islands were previously thought to exist only under perched or dike-impounded conditions, but in the southern Lihue Basin, high water levels exist in an apparently dike-free, fully saturated aquifer. A new conceptual model of groundwater occurrence in shield-volcano islands is needed to explain conditions in the southern Lihue Basin. Résumé. Dans le sud du bassin de Lihue (Kauai, Hawaii, USA), il existe une épaisse lentille d'eau souterraine douce dans une vaste région à faible perméabilité. Le modèle conceptuel conventionnel pour la présence d'eau souterraine à Hawaii et dans les autres îles de volcans en bouclier ne rend pas compte d'une lentille d'eau douce si épaisse. Dans ce modèle conceptuel, les accumulations de lave dont sont formés la plupart des volcans en bouclier couvrent de vastes régions à relativement forte perméabilité, avec des lentilles d'eau douce peu épaisses. Dans le sud du bassin de Lihue, les laves remplissant le bassin et les sédiments constituent une région étendue à faible conductivité hydraulique régionale, qui, sous le climat humide du bassin, est saturée presque jusqu'à sa surface; les surfaces piézométriques sont plusieurs centaines de mètres au-dessus du niveau de la mer à quelques kilomètres de la côte. On pensait jusqu'à présent que des niveaux piézométriques aussi élevés dans des îles de volcans en bouclier n'existaient que dans le cas de nappes perchées ou de blocage par un dyke, mais dans le sud du bassin de Lihue, des niveaux piézométriques élevés existent dans un aquifère apparemment sans dyke et complètement saturé. Un nouveau modèle conceptuel de présence d'eau souterraine dans les îles de volcans en bouclier est nécessaire pour expliquer les conditions observées dans le sud du bassin de Lihue. Resumen. Se ha determinado la existencia de un espeso lentejón de aguas subterráneas dulces en una extensa región de baja permeabilidad situada al sur de la cuenca de Lihue, en Kauai (Hawaii, Estados Unidos de América). El modelo conceptual convencional de las aguas subterráneas en Hawai y en otros cinturones de islas volcánicas no considera la existencia de lentejones tan gruesos de agua dulce. En dicho modelo, las acumulaciones de flujos de lava que constituyen la mayoría de los cinturones volcánicos se desarrollan en grandes áreas de permeabilidad relativamente baja y con pequeños lentejones de agua dulce. En el sur de la cuenca de Lihue, las lavas de relleno y los sedimentos forman una región extensa de baja conductividad hidráulica regional que, con el clima húmedo de la zona, está saturada hasta prácticamente la superficie del terreno, mientras que el nivel freático se encuentra centenares de metros por encima del nivel del mar a pocos kilómetros de la línea de costa. Se creía hasta ahora que, en los cinturones de islas volcánicas, tales niveles sólo tenían lugar en acuíferos colgados o en condiciones de confinamiento por diques, pero, al sur de la cuenca de Lihue, se dan en acuíferos completamente saturados que no están limitados por diques. Se necesita un nuevo modelo conceptual de las aguas subterráneas en cinturones de islas volcánicas para explicar las condiciones halladas en la cuenca meridional de Lihue.

Izuka, Scot; Gingerich, Stephen



Caracterización espectroscópica de hielos de interés atmosférico y astrofísico  

NASA Astrophysics Data System (ADS)

En años recientes se ha incrementado el estudio de procesos físicos y químicos que tienen lugar en la superficie o el interior de hielos, tanto en medios astrofísicos como en la atmósfera terrestre y en otros cuerpos del sistema solar. Se ha comprobado que las partículas heladas actúan como catalizadores de reacciones químicas, que no ocurrirían en su ausencia. En la atmósfera terrestre, es bien conocida la importancia de partículas de hidratos de ácido nítrico, formando las llamadas nubes estratosféricas polares, en los procesos de destrucción de ozono estratosférico. En hielos astrofísicos, átomos como H, C, N y O pueden adherirse o introducirse en la estructura cristalina o amorfa del hielo, y dar lugar a reacciones de formación de moléculas evitando su barrera de activación. Existen partículas heladas en el medio interestelar formando parte de las llamadas nubes moleculares densas y frías, con valores del orden de 106 átomos de H por cm3 y temperaturas entre 3 y 90 K. Alrededor de protoestrellas, pueden formarse hielos de distinta composición, polares o apolares, en las zonas de alejamiento y temperatura decreciente a partir del núcleo caliente. Por su parte, los cometas están formados por un núcleo de hielo y rocas, sobre el que se encuentran adheridas moléculas gaseosas, y una cola, formada por los gases liberados por efecto del calentamiento debido a la radiación solar incidente. En nuestro sistema solar, los polos de La Tierra y de Marte están cubiertos de hielo, así como la mayoría de los cuerpos externos. Los satélites de Júpiter han sido estudiados detalladamente, y se han encontrado en ellos, y en Tritón (satélite de Neptuno), hielos de moléculas como SON2, CO2, N2, CH4 y otros. Para la caracterización espectroscópica de estos hielos se precisan medidas en el laboratorio, aún conociendo la imposibilidad intrínseca de reproducir exactamente las condiciones en que se formaron y se encuentran en los medios astrofísicos. El montaje experimental requiere un sistema que permita alcanzar bajas presiones y temperaturas, formado usualmente por una cámara en cuyo interior se forman películas de hielo de la composición deseada, depositadas sobre un sustrato inerte. Las películas pueden ser a continuación tratadas por diversas técnicas, tales como irradiación UV, bombardeo con electrones o iones, calentamiento y enfriamiento, etc. Habitualmente todos los procesos se controlan por espectroscopía de infrarrojo. La radiación proveniente de un espectrómetro se hace incidir sobre la muestra y se extrae de la cámara mediante ventanas, y se enfoca posteriormente sobre el detector. En el laboratorio de Física Molecular del Instituto de Estructura de la Materia disponemos de un montaje experimental diseñado para el estudio de partículas de hielo similares a las formadas en las nubes estratosféricas polares de nuestra atmósfera. El montaje es similar al descrito anteriormente, excepto en lo que se refiere a las condiciones de presión y temperatura, que son menos estrictas en nuestros experimentos. La extensión de estas condiciones de trabajo a las requeridas en medios astrofísicos es una posibilidad a discutir. Por otra parte, disponemos de un método de cálculo de estructuras periódicas, basado en el programa SIESTA (acrónimo de Spanish Initiative for Electronic Simulations of Thousands of Atoms), que ha proporcionado excelentes resultados en lo relativo a la determinación de estructuras cristalinas y predicción de su espectro infrarrojo, en los sistemas estudiados hasta la fecha, es decir, los hidratos de ácido nítrico de interés atmosféricos. Su aplicación para el estudio de hielos de relevancia astrofísica podría ser del máximo interés.

Escribano, R.