Search results for "FOS"
showing 10 items of 15075 documents
The case of equality in the dichotomy of Mohammadi-Oh
2017
If $n \geq 3$ and $\Gamma$ is a convex-cocompact Zariski-dense discrete subgroup of $\mathbf{SO}^o(1,n+1)$ such that $\delta_\Gamma=n-m$ where $m$ is an integer, $1 \leq m \leq n-1$, we show that for any $m$-dimensional subgroup $U$ in the horospheric group $N$, the Burger-Roblin measure associated to $\Gamma$ on the quotient of the frame bundle is $U$-recurrent.
IBRIDI FORMATI DA NANOTUBI DI CARBONIO A PARETE MULTIPLA E ESTERI FOSFORICI: PROPRIETA’ E STUDI STRUTTURALI
2012
Nel corso degli ultimi anni i nanotubi di carbonio in virtù delle loro proprietà fisiche, chimiche e meccaniche sono diventati tra i più promettenti materiali per la realizzazione di congegni a livello nanometrico. I CNT trovano numerose applicazioni nel campo, della nanoelettronica, nella costruzione di materiali ad elevata conducibilità elettrica ed elevata resistenza meccanica,2 e vengono, anche, impiegati come agenti di rinforzo dispersi in una matrice polimerica.3 Problema principale di questi materiali è che essi risultano scarsamente solubili in ambiente acquoso e in solventi organici, a causa delle forti forze attrattive di van der Waals che esistono tra le superfici dei CNT, che li…
Interazioni non covalenti tra esteri fosforici e nanotubi di carbonio a parete multipla
2010
Fin dal 1991, quando Iijima li osservò per la prima volta, i nanotubi di carbonio (CNT) sono diventati oggetto d'interesse scientifico, in virtù delle loro proprietà fisiche, chimiche e meccaniche. Un impiego molto interessante riguarda l'aumento di stabilità di matrici polimeriche. I nanocompositi polimerici, in cui sono presenti percentuali molto basse di CNT (2.5%), presentano enormi miglioramenti nelle caratteristiche termomeccaniche, nella resistenza al calore e nella conduttività elettrica. C'è, però, un impedimento fondamentale a tutte le applicazioni che riguarda l'insolubilità intrinseca dei CNT nei solventi. La funzionalizzazione sia essa covalente che non è un espediente per ovvi…
Estudio y modulación del metabolismo del glutatión en la tolerancia al estrés oxidativo generado por plaguicidas en organismos acuáticos de interés c…
2003
La utilización de plaguicidas para el cultivo del arroz en campos cercanos a humedales de gran valor ecológico como los Parques Naturales de la Albufera de Valencia y el Delta del Ebro (Tarragona) suponen un riesgo no sólo para los ecosistemas de estos Parques sino también para la pesca y acuicultura que se desarrolla en la zona. La anguila europea (Anguilla anguilla) reside en ambos hábitats y está expuesta a cantidades considerables de herbicidas tiocarbamatos como el molinato y tiobencarb. Estos plaguicidas disminuyen y oxidan los niveles del antioxidante intracelular más importante, el glutatión (GSH). Así, se ha descubierto que el principal mecanismo de toxicidad de los herbicidas tioc…
Euler Characteristics of Moduli Spaces of Curves
2005
Let ${mathcal M}_g^n$ be the moduli space of n-pointed Riemann surfaces of genus g. Denote by ${\bar {\mathcal M}}_g^n$ the Deligne-Mumford compactification of ${mathcal M}_g^n$. In the present paper, we calculate the orbifold and the ordinary Euler characteristic of ${\bar {\mathcal M}}_g^n$ for any g and n such that n>2-2g.
Optically pumped Cs magnetometers enabling a high-sensitivity search for the neutron electric dipole moment
2020
An array of 16 laser-pumped scalar Cs magnetometers was part of the neutron electric dipole moment (nEDM) experiment taking data at the Paul Scherrer Institute in 2015 and 2016. It was deployed to measure the gradients of the experiment's magnetic field and to monitor their temporal evolution. The originality of the array lies in its compact design, in which a single near-infrared diode laser drives all magnetometers that are located in a high-vacuum chamber, with a selection of the sensors mounted on a high-voltage electrode. We describe details of the Cs sensors' construction and modes of operation, emphasizing the accuracy and sensitivity of the magnetic-field readout. We present two app…
First measurement of proton's charge form factor at very low $Q^2$ with initial state radiation
2017
We report on a new experimental method based on initial-state radiation (ISR) in e-p scattering, in which the radiative tail of the elastic e-p peak contains information on the proton charge form factor ($G_E^p$) at extremely small $Q^2$. The ISR technique was validated in a dedicated experiment using the spectrometers of the A1-Collaboration at the Mainz Microtron (MAMI). This provided first measurements of $G_E^p$ for $0.001\leq Q^2\leq 0.004 (GeV/c)^2$.
Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009
2017
Astronomy and astrophysics 603, A31 (2017). doi:10.1051/0004-6361/201629540
Ezeru nogulumu netiešā datēšana, izmantojot sfērisko daļiņu identificēšanas metodi
2019
Bakalaura darbs ir par fosilo kurināmo izdedžu sfērisko daļiņu identificēšanas analīzi ezeru nogulumos, nosakot paraugos sfēriskās oglekļa daļiņas (SCP) un neorganiskās daļiņas (IAP), un to izmantošanu nogulumu datēšanā. Pētījumā analizēti divu ezeru nogulumi – Lielais Vipēdis (Zemgale) un Bricu (Vidzeme). Kopumā, rezultāti uzrāda loģiskas sfērisko daļiņu koncentrāciju izmaiņas ar strauju pieaugumu ap 1950. gadu, maksimālo koncentrāciju ap 1980. gadu un strauju samazinājumu pēc 1991. gada, kas skaidrojams ar politiskām un ekonomiskām izmaiņām laika gaitā. Iegūtie rezultāti norādīja, ka sfērisko daļiņu koncentrāciju ezeros ietekmē sedimentācijas apstākļi, bet, galvenokārt, atšķirības rada vē…
Normalizēto slāpekļa un fosfora savienojumu upju slodžu izvērtējums no 2000.-2011.gadam Latvijā
2015
Pētījumā analizētas slāpekļa un fosfora un to savienojumu slodzes, izmantojot četras dažādas aprēķinu metodes – divas faktiskās un divas normalizēto upju slodžu aprēķinu metodes. Rezultātā noteikts, ka aprēķinu rezultāti var atšķirties, turklāt atsevišķos gadījumos starp rezultātiem sasniedzot vairāk nekā 50% starpību, tomēr metodes ir savstarpēji salīdzināmas. Modelējot normalizētās upju slodzes kā, galvenais, mainīgais laikā ir upes caurplūdums un, veicot slodžu modelēšanu, iegūtie rezultāti liecina, ka normalizēto slodžu aprēķini lielākoties pie maziem upes caurplūdumiem dod ievērojami lielākas upju slodzes, bet pie augstākiem upes caurplūdumiem – ievērojami zemākas. Pēc Manna-Kendala te…