EPR and ferromagnetism in diluted magnetic semiconductor quantum wells

Motivated by recent measurements of electron paramagnetic resonance (EPR) spectra in modulation-doped CdMnTe quantum wells, [F.J. Teran {\it et al.}, Phys. Rev. Lett. {\bf 91}, 077201 (2003)], we develop a theory of collective spin excitations in quasi-two-dimensional diluted magnetic semiconductors (DMSs). Our theory explains the anomalously large Knight shift found in these experiments as a consequence of collective coupling between Mn-ion local moments and itinerant-electron spins. We use this theory to discuss the physics of ferromagnetism in (II,Mn)VI quantum wells, and to speculate on the temperature at which it is likely to be observed in n-type modulation doped systems.Comment: 4 pages, 1 figur

Tailoring magnetic anisotropy in epitaxial half metallic La0.7Sr0.3MnO3 thin films

We present a detailed study on the magnetic properties, including anisotropy, reversal fields, and magnetization reversal processes, of well characterized half-metallic epitaxial La0.7Sr0.3MnO3 (LSMO) thin films grown onto SrTiO3 (STO) substrates with three different surface orientations, i.e. (001), (110) and (1-18). The latter shows step edges oriented parallel to the [110] (in-plane) crystallographic direction. Room temperature high resolution vectorial Kerr magnetometry measurements have been performed at different applied magnetic field directions in the whole angular range. In general, the magnetic properties of the LSMO films can be interpreted with just the uniaxial term with the anisotropy axis given by the film morphology, whereas the strength of this anisotropy depends on both structure and film thickness. In particular, LSMO films grown on nominally flat (110)-oriented STO substrates presents a well defined uniaxial anisotropy originated from the existence of elongated in-plane [001]-oriented structures, whereas LSMO films grown on nominally flat (001)-oriented STO substrates show a weak uniaxial magnetic anisotropy with the easy axis direction aligned parallel to residual substrate step edges. Elongated structures are also found for LSMO films grown on vicinal STO(001) substrates. These films present a well-defined uniaxial magnetic anisotropy with the easy axis lying along the step edges and its strength increases with the LSMO thickness. It is remarkable that this step-induced uniaxial anisotropy has been found for LSMO films up to 120 nm thickness. Our results are promising for engineering novel half-metallic magnetic devices that exploit tailored magnetic anisotropy.Comment: 10 pages, 10 figures, 1 tabl

A severe case of erythrodermic psoriasis associated with advanced nail and joint manifestations: a case report

<p>Abstract</p> <p>Introduction</p> <p>Erythrodermic psoriasis is a rare generalized clinical presentation of psoriasis in children and adults. Its systemic involvement and a diverse range of clinical findings in the joint and nails are commonly described. A high index of suspicion and an exhaustive differential diagnosis involving other causes of erythroderma should be initially considered.</p> <p>Case presentation</p> <p>We present the case of a 9-year-old native Hispanic girl with severe erythrodermic psoriasis associated with uncommon advanced nail and joint manifestations. Our patient showed an excellent response to methotrexate medication.</p> <p>Conclusion</p> <p>This case shows clinical features not commonly described or reported in severe cases of erythrodermic psoriasis, including severe and rare nail and arthritic findings in a pediatric scenario.</p

REVIZIJA DUGOTRAJNE MATERIJALNE I NEMATERIJALNE IMOVINE : Završni rad

Godišnji financijski izvještaji bi trebali prikazivati istinit, fer, pouzdan i nepristran pregled imovine, obveza, kapitala, dobiti ili gubitaka u određenoj poslovnoj godini. Budući da je računovodstveni regulatorni okvir do nekih granica fleksibilan, poduzetnici to često zloupotrebljavaju. Upravo mogućnost odabira određene računovodstvene politike, te samo utvrđivanje fer vrijednosti predstavljaju područja na koja utječu subjektivni stavovi menadžmenta te pripadaju području rizika. Glavni cilj revizije je provjera i ocjena financijskih izvještaja te upravo pojavom tog postupka povećava se razina povjerenja i sigurnosti u same financijske izvještaje. Ovim radom željela se skreniti pozornost na moguće netočne iskaze uslijed pogreške ili prijevare na poziciji dugotrajne materijalne i nematerijalne imovine te analiza istih. Analizom je utvrđeno da je većina hotela koji listaju na burzi u 2017. godini izvršila ispravak i prikazala svoj financijski položaj realno i objektivno, te je time zabilježeno manje modificiranih mišljenja koji za osnovu uzimaju greške na poziciji dugotrajne materijalne i nematerijalne imovine.The annual financial statements should show a true, fair, reliable and impartial review of assets, liabilities, capital, gains or losses in a given business year. Since the accounting regulatory framework is flexible to some limits, entrepreneurs often abuse them. Precisely the option of selecting a particular accounting policy, and just determining fair value, represent areas influenced by subjective managerial attitudes and belong to the risk area. The main purpose of the audit is to verify and evaluate the financial statements, and as a result of this process, the level of trust and confidence increases in the financial statements. This paper wanted to draw attention to possible incorrect statements as a result of errors or deception in the position of long-term material and non-material assets and their analysis. The analysis found that most of the hotels listed on the stock exchanges in 2017 made a correction and presented their financial position in a realistic and objective manner and thus recorded less modified opinions based on taking long-term tangible and intangible assets

Ising Quantum Hall Ferromagnet in Magnetically Doped Quantum Wells

We report on the observation of the Ising quantum Hall ferromagnet with Curie temperature $T_C$ as high as 2 K in a modulation-doped (Cd,Mn)Te heterostructure. In this system field-induced crossing of Landau levels occurs due to the giant spin-splitting effect. Magnetoresistance data, collected over a wide range of temperatures, magnetic fields, tilt angles, and electron densities, are discussed taking into account both Coulomb electron-electron interactions and s$-$d coupling to Mn spin fluctuations. The critical behavior of the resistance ``spikes'' at $T \to T_C$ corroborates theoretical suggestions that the ferromagnet is destroyed by domain excitations.Comment: revised, 4 pages, 4 figure

Urban water security: a comparative study of cities in the arid Americas

In this study we analyse how three cities in the arid Americas have addressed urban growth while facing water scarcity: Hermosillo, Mexico; Mendoza, Argentina; and Tucson, USA. We use the urban water security framework to examine five domains of water management: sociodemographic, economic, technological, ecological and governance (SETEG). Our analysis indicates that, in spite of water scarcity, urban growth has been promoted in the three cities. We argue that this expansion, although encouraged for economic development, is not sustainable in the long term. In the three cities, groundwater plays a major role in water supply, but growth has negatively affected riparian ecosystems, the health of the aquifers and access to domestic water. In order to pursue water security, several options are essential to enhance social?ecological system resilience. These include limits or reduction of urban expansion, reuse of treated effluent for riparian conservation, and community conservation efforts such as rainwater harvesting and other green infrastructure practices.Fil: Díaz Caravantes, Rolando E.. El Colegio de Sonora; MéxicoFil: Zuniga Teran, Adriana. University of Arizona; Estados UnidosFil: Martin, Facundo Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Bernabeu, María Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ciencias Humanas, Sociales y Ambientales; ArgentinaFil: Stoker, Philip. University of Arizona; Estados UnidosFil: Scott, Christopher. University of Arizona; Estados Unido