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Wyszukujesz frazę "García, Ricardo" wg kryterium: Autor


Tytuł:
Banach spaces in which all multilinear forms are weakly sequentially continuous
Autorzy:
Castillo, Jesús M.F.
García, Ricardo
Gonzalo, Raquel
Tematy:
multilinear forms
polynomials
weak continuity
Pokaż więcej
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Powiązania:
https://bibliotekanauki.pl/articles/1216281.pdf  Link otwiera się w nowym oknie
Opis:
We solve several problems in the theory of polynomials in Banach spaces. (i) There exist Banach spaces without the Dunford-Pettis property and without upper p-estimates in which all multilinear forms are weakly sequentially continuous: some Lorentz sequence spaces, their natural preduals and, most notably, the dual of Schreier's space. (ii) There exist Banach spaces X without the Dunford-Pettis property such that all multilinear forms on X and X* are weakly sequentially continuous; this gives an answer to a question of Dimant and Zalduendo [20]. (iii) The sum of two polynomially null sequences need not be polynomially null; this answers a question of Biström, Jaramillo and Lindström [8] and also of González and Gutiérrez [23]. (iv), (v) The absolutely convex closed hull of a pw-compact set need not be pw-compact; the projective tensor product of two polynomially null sequences need not be a polynomially null sequence. This answers two questions of González and Gutiérrez [23]. (vi) There exists a Banach space without property (P); this answers a question of Aron, Choi and Llavona [5].
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationship between body composition and bone mineral density in American football players
Relación entre composición corporal y densidad mineral ósea en jugadores de fútbol americano
Autorzy:
López García, Ricardo
Lagunes Carrasco, José Omar
Carranza García, Luis Enrique
Navarro Orocio, Ricardo
Tematy:
Fútbol americano
mineral óseo
masa magra
DEXA
IMC.
American football
bone mineral density
lean mass
BMI
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Wydawca:
Atena Research Association
Powiązania:
https://bibliotekanauki.pl/articles/1491262.pdf  Link otwiera się w nowym oknie
Opis:
Objetivos: El objetivo de este estudio fue relacionar el índice de masa corporal (IMC) y la composición corporal con la densidad mineral ósea (DMO) en jugadores de fútbol americano universitario. Métodos: Participaron un total de 90 jugadores (22.44 + 1.71 años de edad), de la liga mayor de fútbol americano universitario en México. Se utilizó el equipo de la absorciometría dual de rayos X (DEXA), en la cual se obtuvieron los valores del IMC, masa grasa, masa magra, masa total y la DMO. Resultados: Los jugadores que presentaron un mayor IMC obtuvieron una mayor DMO. Conclusiones: si observamos que la mayoría de los jugadores suelen tener problemas de sobrepeso y obesidad, encontramos que la masa grasa no se asocia con la DMO, es decir, que el jugador a pesar de tener un peso corporal elevado, su beneficio de la elevada DMO se debe a la alta cantidad de masa magra.
Objectives: The objective of this study was to assess the relation between body composition and body mass index (BMI) to bone mineral density (BMD) in college American football players. Methods: A total of 90 players (22.44 + 1.71 years old) from the major college football league in Mexico participated. The dual-energy X-ray absorptiometry (DEXA) equipment was used, in which the values of BMI, fat mass, lean mass, total mass and BMD were obtained. Findings: Players who had higher BMI got higher BMD. The strongest significant positive correlations found were lean mass, body weight, and BMI with BMD of the arms, legs, trunk, and spine. Conclusions: Most of the players analyzed had problems of excess weight and obesity, however, those who had a higher BMI such as obesity type I, II and III had also higher BMD than those with excess weight and normal weight, with significant differences in the regions of arms, legs, spine and total body.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On a question of Pełczyński about multilinear operators
Mathematics
Bulletin of the Polish Academy of Sciences. Mathematics.
Bulletin of the Polish Academy of Sciences
Autorzy:
Villanueva Díez, Ignacio
García González, Ricardo
Cabello Sánchez, Félix
Współwytwórcy:
Polska Akademia Nauk.
Wydawca:
Polska Akademia Nauk. Centrum Upowszechniania Nauki.
Opis:
Text in English
Tekst w jęz. angielskim
24 cm
Dostawca treści:
RCIN - Repozytorium Cyfrowe Instytutów Naukowych
Książka
Tytuł:
A note on centrifugation for improving freshwater invertebrate sample conservation
Autorzy:
Valdecasas, Antonio G.
García-Jiménez, Ricardo
Marín F.-Campoamor, Mercedes
Tematy:
live sorting
sampling trips
optimal sample conservation
benthos
streams
sortowanie przeżyciowe
wyprawy badawcze
optymalna ochrona próbek
bentos
strumienie
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Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Powiązania:
https://bibliotekanauki.pl/articles/1386435.pdf  Link otwiera się w nowym oknie
Opis:
Sorting of freshwater invertebrate samples is best done while the animals are still alive. However, sorting in the field generally means less overall sampling can be done in the allotted time. Placing samples under cold conditions has been the traditional way to extend the life of the organisms contained within them. In this work, we evaluated whether the addition of a centrifugation step extends the survival time of organisms post-sampling, thus providing more time for sorting. Three salad spinners were tested for their capacity to extract water from samples. Additional observations were made on the compaction of samples due to excessive centrifugation. We conclude that adding a short centrifugation step of 30 seconds prolongs the life of several freshwater invertebrate taxa, including Hydrachnidia, Nematoda and Ostracoda. Furthermore, when fixation of samples in the field is necessary, centrifugation reduces the amount of fixative to be added to the samples to reach a certain concentration. Fixed samples can also be centrifuged, which may be particularly relevant when sampling abroad as inflam-mable liquids are often prohibited on planes. In our experience, centrifuging fixed samples does not compromise the fixed organisms, or their genetic material.
Sortowanie prób bezkręgowców słodkowodnych najlepiej wykonywać przeżyciowo, jednak sortowanie w terenie prowadzi na ogół do ograniczenia liczby wybieranych taksonów w wy-znaczonym czasie. Umieszczanie próbek w niskich temperaturach jest tradycyjnym sposobem przedłużania życia zawartych w nich organizmów. W tej pracy oceniliśmy, czy dodanie etapu wirowania wydłuża czas przeżycia organizmów po pobraniu próbek, zapewniając tym samym więcej czasu na sortowanie. Trzy odsączarki do warzyw przetestowano pod kątem ich zdolności do ekstrakcji wody z próbek. Dodatkowe obserwacje dotyczyły zagęszczenia próbek w wyniku nadmiernego wirowania. Doszliśmy do wniosku, że dodanie krótkiego, 30-sekundowego etapu wirowania przedłuża życie kilku taksonów bezkręgowców słodko-wodnych, w tym Hydrachnidia, Nematoda i Ostracoda. Ponadto, gdy konieczne jest utrwalenie próbek w terenie, wirowanie zmniejsza ilość środka utrwalającego dodawanego do próbek, aby osiągnąć określone stężenie. Utrwalone próbki można również odwirować, co może być szczególnie istotne w przypadku pobierania próbek za granicą, ponieważ płyny łatwopalne są często zabronione w samolotach. Z naszego doświadczenia wynika, że wirowanie utrwalonych próbek nie zagraża utrwalonym organizmom ani ich materiałowi genetycznemu.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Results on 4-Transitive Digraphs
Autorzy:
García-Vázquez, Patricio Ricardo
Hernández-Cruz, César
Tematy:
4-transitive digraph
k -transitive digraph
3-kernel
k -kernel
Laborde-Payan-Xuong Conjecture
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Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Powiązania:
https://bibliotekanauki.pl/articles/31342166.pdf  Link otwiera się w nowym oknie
Opis:
Let D be a digraph with set of vertices V and set of arcs A. We say that D is k-transitive if for every pair of vertices u, v ∈ V, the existence of a uv-path of length k in D implies that (u, v) ∈ A. A 2-transitive digraph is a transitive digraph in the usual sense. A subset N of V is k-independent if for every pair of vertices u, v ∈ N, we have d(u, v), d(v, u) ≥ k; it is l-absorbent if for every u ∈ V \ N there exists v ∈ N such that d(u, v) ≤ l. A k-kernel of D is a k-independent and (k − 1)-absorbent subset of V. The problem of determining whether a digraph has a k-kernel is known to be NP-complete for every k ≥ 2. In this work, we characterize 4-transitive digraphs having a 3-kernel and also 4-transitive digraphs having a 2-kernel. Using the latter result, a proof of the Laborde-Payan-Xuong conjecture for 4-transitive digraphs is given. This conjecture establishes that for every digraph D, an independent set can be found such that it intersects every longest path in D. Also, Seymour’s Second Neighborhood Conjecture is verified for 4-transitive digraphs and further problems are proposed.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new consistent neutron star equation of state from a generalized Skyrme model
Autorzy:
Wereszczyński, Andrzej
Huidobro Garcia, Miguel
García Martín-Caro, Alberto
Adam, Christoph
Vazquez, Ricardo
Opis:
We propose a new equation of state for nuclear matter based on a generalized Skyrme model which is consistent with all current constraints on the observed properties of neutron stars. This generalized model depends only on two free parameters related to the ranges of pressure values at which different submodels are dominant, and which can be adjusted so that mass-radius and deformability constraints from astrophysical and gravitational wave measurements can be met. Our results support the Skyrme model and its generalizations as good candidates for a low energy effective field-theoretic description of nuclear matter even at extreme conditions such as those inside neutron stars.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Feasibility study for a fuel cell-powered unmanned aerial vehicle with a 75 kg payload
Autorzy:
Desantes, José M.
Novella, Ricardo
García-Cuevas, Luis M.
Lopez-Juarez, Marcos
Tematy:
Unmanned Aerial Vehicle
fuel cell
hydrogen
optimization
Pokaż więcej
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Powiązania:
https://bibliotekanauki.pl/articles/36455727.pdf  Link otwiera się w nowym oknie
Opis:
Among the possible electric powerplants currently driving low-payload UAVs (up to around 10 kg of payload), batteries offer certain clear benefits, but for medium-payload operation such as aerotaxis and heavy-cargo transportation UAVs, battery capacity requirements restrict their usage due to high weight and volume. In light of this situation, fuel cell (FC) systems (FCS) offer clear benefits over batteries for the medium-payload UAV segment (> 50 kg). Nevertheless, studies regarding the application of FCS powerplants to this UAV segment are limited and the in-flight performance has not been clearly analysed. In order to address this knowledge gap, a feasibility analysis of these particular applications powered by FCS is performed in this study. A validated FC stack model (40 kW of maximum power) was integrated into a balance of plant to conform an FCS. As a novelty, the management of the FCS was optimized to maximize the FCS efficiency at different altitudes up to 12500 ft, so that the operation always implies the lowest H2 consumption regardless of the altitude. In parallel, an UAV numerical model was developed based on the ATLANTE vehicle and characterized by calculating the aerodynamic coefficients through CFD simulations. Then, both models were integrated into a 0D-1D modelling platform together with an energy management strategy optimizer algorithm and a suitable propeller model. With the preliminary results obtained from the FCS and UAV models, it was possible to ascertain the range and endurance of the vehicle. As a result, it was concluded that the combination of both technologies could offer a range over 600 km and an endurance over 5 h. Finally, with the integrated UAV-FCS model, a flight profile describing a medium altitude, medium endurance mission was designed and used to analyse the viability of FC-powered UAV. The results showed how UAVs powered by FCS are viable for the considered aircraft segment, providing competitive values of specific range and endurance.
Dostawca treści:
Biblioteka Nauki
Artykuł

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