Search results for "78"
showing 10 items of 1163 documents
A note on Kakeya sets of horizontal and SL(2) lines
2022
We consider unions of $SL(2)$ lines in $\mathbb{R}^{3}$. These are lines of the form $$L = (a,b,0) + \mathrm{span}(c,d,1),$$ where $ad - bc = 1$. We show that if $\mathcal{L}$ is a Kakeya set of $SL(2)$ lines, then the union $\cup \mathcal{L}$ has Hausdorff dimension $3$. This answers a question of Wang and Zahl. The $SL(2)$ lines can be identified with horizontal lines in the first Heisenberg group, and we obtain the main result as a corollary of a more general statement concerning unions of horizontal lines. This statement is established via a point-line duality principle between horizontal and conical lines in $\mathbb{R}^{3}$, combined with recent work on restricted families of projecti…
On the Dimension of Kakeya Sets in the First Heisenberg Group
2021
We define Kakeya sets in the Heisenberg group and show that the Heisenberg Hausdorff dimension of Kakeya sets in the first Heisenberg group is at least 3. This lower bound is sharp since, under our definition, the $\{xoy\}$-plane is a Kakeya set with Heisenberg Hausdorff dimension 3.
Storm Energy Flux Characterization along the Mediterranean Coast of Andalusia (Spain)
2019
This paper investigates wave climate and storm characteristics along the Mediterranean coast of Andalusia, for the period 1979&ndash
Dune systems' characterization and evolution in the andalusia mediterranean coast (Spain)
2020
This paper deals with the characterization and evolution of dune systems along the Mediterranean coast of Andalusia, in the South of Spain, a first step to assess their relevant value in coastal flood protection and in the determination of sound management strategies to protect such valuable ecological systems. Different dune types were mapped as well as dune toe position and fragmentation, which favors dune sensitivity to storms&rsquo
Future Climate Forcings and Olive Yield in a Mediterranean Orchard
2014
The olive tree is one of the most characteristic rainfed trees in the Mediterranean region. Observed and forecasted climate modifications in this region, such as the CO2 concentration and temperature increase and the net radiation, rainfall and wind speed decrease, will likely alter vegetation water stress and modify productivity. In order to simulate how climatic change could alter soil moisture dynamic, biomass growth and fruit productivity, a water-driven crop model has been used in this study. The numerical model, previously calibrated on an olive orchard located in Sicily (Italy) with a satisfactory reproduction of historical olive yield data, has been forced with future climate scenar…
Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils
2017
Assessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration experi…
Treatment of Oily Wastewater with Membrane Bioreactor Systems
2017
The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants, extracellular polymeric substances production, and membrane fouling rates were monitored. The MBR plant was operated for more than 200 days, and the results highlighted good carbon removal and nitrification, suggesting a sort of biomass adaptation to hydrocarbons. Membrane fouling analysis showed an increase in total resistance, likely due to hydrocarbons, which caused an irreversible fouling (pore blocking) mainly…
Brief an Karl Axel Christer Freiherr von Bruiningk
1839
Ms. 930a, Nr. 6b, Bl. 19r-19v Merkel, Garlieb H. Brief an Karl Axel Christer Freiherr von Bruiningk, [Depkinshof ?], [bez datuma; ohne Datum, pēc / nach 1839] Autora rokraksts / Autograph, vācu val. / Deutsch, [2] lpp. / S. Attēlu numuri / Bildnummern: 930a-006b-1 – 930a-006b-2 In dem undatierten Entwurf einer Antwort auf einen Brief Bruiningks [womit der unter Ms. 930a, Nr. 6a gemeint wird, bleibt noch unklar] lobt Merkel dessen Einsatz für die Bauernbefreiung. Das Problem des fehlenden Grundbesitzes für die freigelassenen Bauern sei ein Grund für die wirtschaftliche Rückständigkeit der „vaterländische[n] Provinzen“. Selbst in Posen (Preußen) und Galizien (Österreich) hätte die wirtschaftl…
Bioactive metabolites from the endophytic fungus Ampelomyces sp. isolated from the medicinal plant Urospermum picroides
2007
Extracts of cultures grown in liquid or on solid rice media of the fungal endophyte Ampelomyces sp. isolated from the medicinal plant Urospermum picroides exhibited considerable cytotoxic activity when tested in vitro against L5178Y cells. Chromatographic separation yielded 14 natural products that were unequivocally identified based on their 1H and 13C NMR as well as mass spectra and comparison with previously published data. Six compounds (2, 4, 5, 7, 9 and 11) were natural products. Both fungal extracts differed considerably in their secondary metabolites. The extract obtained from liquid cultures afforded a pyrone (2) and sulfated anthraquinones (7 and 9) along with the known compounds …
Mitochondrial dynamics in type 2 diabetes: Pathophysiological implications
2017
Mitochondria play a key role in maintaining cellular metabolic homeostasis. These organelles have a high plasticity and are involved in dynamic processes such as mitochondrial fusion and fission, mitophagy and mitochondrial biogenesis. Type 2 diabetes is characterised by mitochondrial dysfunction, high production of reactive oxygen species (ROS) and low levels of ATP. Mitochondrial fusion is modulated by different proteins, including mitofusin-1 (MFN1), mitofusin-2 (MFN2) and optic atrophy (OPA-1), while fission is controlled by mitochondrial fission 1 (FIS1), dynamin-related protein 1 (DRP1) and mitochondrial fission factor (MFF). PARKIN and (PTEN)-induced putative kinase 1 (PINK1) partici…