2,351 research outputs found

    Spin injection from EuS/Co multilayers into GaAs detected by polarized electroluminescence

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    We report on the successful spin injection from EuS/Co multilayers into (100) GaAs at low temperatures. The spin injection was verified by means of polarized electroluminescence (EL) emitted from AlGaAs/GaAs-based spin-light-emitting diodes in zero external magnetic field. Spin-polarized electrons were injected from prototype EuS/Co spin injector multilayers. The use of semiconducting and ferromagnetic EuS circumvents the impedance mismatch. The EL was measured in side emission with and without an external magnetic field. A circular polarization of 5% at 8 K and 0 T was observed. In view of the rather rough interface between the GaAs substrate and first EuS layer, improvement of the interface quality is expected to considerably enhance the injected electron spin polarization

    β-blockers : their new life from hypertension to cancer and migraine

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    The pharmacological class of \u3b2-blockers includes a plea of molecules with largely different pharmacokinetic and pharmacodynamic characteristics with a protective effect that may span far beyond the cardiovascular system. Although all these compounds share the pharmacological blockade of the adrenergic receptors, each of them is characterized by specific pharmacological properties, including selectivity of action depending on the adrenergic receptors subtypes, intrinsic sympathomimetic activity (ISA), lipid solubility, pharmacokinetic profile, and also other ancillary properties that impact their clinical effect. Their use in the treatment of hypertension has been extensively debated and at the moment a class indication is not present. However, in specific niche of patients, such as in those young individuals in which hypertension is mainly driven by a sympathetic hyperactivation, strong evidence pose \u3b2-Blockers as a highly reasonable \ufb01rst-line treatment. Lipophilic \u3b2-blockers, specifically propranolol and metoprolol, can cross the Blood Brain Barrier and have a Class A indication for the prophylactic treatment of migraine attacks. Moreover, since \u3b2-adrenergic receptors affect the proliferative process of both cancer and immune cells, their blockade has been associated with metastasis reduction in several epithelial and solid organ tumors posing \u3b2-Blockers as a new attractive, inexpensive and relatively safe therapeutic strategy in patients with several types of cancer. However, further dedicated prospective, randomized, placebo-controlled studies are needed to determine the real efficacy of these compounds

    Directly imaging damped Ly α galaxies at z > 2 – III. The star formation rates of neutral gas reservoirs at z ∼ 2.7

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    We present results from a survey designed to probe the star formation properties of 32 damped Lyman α systems (DLAs) at z ∼ 2.7. By using the ‘double-DLA’ technique that eliminates the glare of the bright background quasars, we directly measure the rest-frame far-ultraviolet flux from DLAs and their neighbouring galaxies. At the position of the absorbing gas, we place stringent constraints on the unobscured star formation rates (SFRs) of DLAs to 2σ limits of ψ˙<0.09-0.27M⊙ yr−1, corresponding to SFR surface densities Σsfr < 10−2.6–10−1.5M⊙ yr−1 kpc−2. The implications of these limits for the star formation law, metal enrichment, and cooling rates of DLAs are examined. By studying the distribution of impact parameters as a function of SFRs for all the galaxies detected around these DLAs, we place new direct constraints on the bright end of the UV luminosity function of DLA hosts. We find that ≤13 per cent of the hosts have ψ˙≥2M⊙ yr−1 at impact parameters bdla≤(ψ˙/M⊙yr−1)0.8+6kpc, differently from current samples of confirmed DLA galaxies. Our observations also disfavour a scenario in which the majority of DLAs arise from bright Lyman-break galaxies at distances 20 ≤ bdla < 100 kpc. These new findings corroborate a picture in which DLAs do not originate from highly star-forming systems that are coincident with the absorbers, and instead suggest that DLAs are associated with faint, possibly isolated, star-forming galaxies. Potential shortcomings of this scenario and future strategies for further investigation are discussed

    Cardiac rhythm analysis during ongoing cardiopulmonary resuscitation using the Analysis During Compressions with Fast reconfirmation technology

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    BACKGROUND Pauses in chest compressions (CCs) have a negative association with survival from cardiac arrest. Electrocardiographic (ECG) rhythm analysis and defibrillator charging are significant contributors to CC pauses. OBJECTIVE Accuracy of the Analysis During Compressions with Fast Reconfirmation (ADC-FR) algorithm, which features automated rhythm analysis and charging during CCs to reduce CC pauses, was retrospectively determined in a large database of ECGs from 2701 patients with out-of-hospital cardiac arrest. METHODS The ADC-FR algorithm generated a total of 7264 advisories, of which 3575 were randomly assigned to a development data set and 3689 to a test data set. With ADC-FR, a high-pass digital filter is used to remove CC artifacts, while the underlying ECG rhythm is automatically interpreted. When CCs are paused at the end of the 2-minute cardiopulmonary resuscitation interval, a 3-second reconfirmation analysis is performed using the artifact-free ECG to confirm the shock/no-shock advisory. The sensitivity and specificity of the ADC-FR algorithm in correctly identifying shockable/nonshockable rhythms during CCs were calculated. RESULTS In both data sets, the accuracy of the ADC-FR algorithm for each ECG rhythm exceeded the recommended performance goals, which apply to a standard artifact-free ECG analysis. Sensitivity and specificity were 97% and 99%, respectively, for the development data set and 95% and 99% for the test data set. CONCLUSION The ADC-FR algorithm is highly accurate in discriminating shockable and nonshockable rhythms and can be used to reduce CC pauses

    Directly imaging damped Lyα galaxies at z > 2 – II. Imaging and spectroscopic observations of 32 quasar fields

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    Damped Lyα absorbers (DLAs) are a well-studied class of absorption line systems, and yet the properties of their host galaxies remain largely unknown. To investigate the origin of these systems, we have conducted an imaging survey of 32 quasar fields with intervening DLAs between z ∼ 1.9 and 3.8, leveraging a technique that allows us to image galaxies at any small angular separation from the background quasars. In this paper, we present the properties of the targeted DLA sample, new imaging observations of the quasar fields, and the analysis of new and archival spectra of the background quasars

    An Exploratory Study of Users&#8217; Preference for Different Planting Combinations along Rural Greenways

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    The literature highlights the importance of vegetation to enhance the ecological and visual qualities of streets and paths; however, when studies specifically focus on rural greenways they do not consider users' assessments of the planting design. This exploratory study aims to contribute to this issue. It is hypothesized that planting combinations characterized by greater variety and aesthetic flow may be more preferred and restorative. To this end, four virtual scenarios simulating bikers moving along a greenway at 25 km/h were created to find out the following: first, what kind of planting combination is the most preferred, and second, which planting combination is perceived as the most restorative by bicycle riders. To assess the experience, subjects were administered a questionnaire made up of: (i) the Perceived Restorativeness Scale-11 with additional items to assess compatibility, familiarity, and preference; (ii) a list of physical and aesthetic attributes; and (iii) information on bicycle use. The results show that participants' preferences were a ffected by the perception of the scenario's restorative value, which was not given exclusively by the degree of naturalness, but by the opportunity the greenway o ffered to engage in social/physical activities. This study shows that preference and restorativeness are not a "simple" matter of quantity of vegetation, but of quality instead, i.e., planting variety. Designers have to consider that the restorative value of greenways is related to the opportunities they offer to engage in physical/social activities

    I WATERFRONT EXTRAURBANI : ELEMENTI PER LA RIQUALIFICAZIONE DEL PAESAGGIO DI FRANGIA

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    Il territorio di frangia urbana presenta al suo interno molteplici usi del suolo tra i quali si trovano spesso anche porzioni di corsi d\u2019acqua che, assieme con alcuni frammenti di vegetazione spontanea ancora presenti, si snodano fra aree urbanizzate, vie di comunicazione e porzioni via via crescenti di territori agricoli. Tale sovrapposizione di funzioni spesso si risolve in un paesaggio estremamente disordinato privo di elementi connotativi guida e ricco di spazi residuali. In tale contesto il tracciato dei corsi d\u2019acqua (waterfront) pu\uf2 rappresentare un elemento guida per la riqualificazione delle aree di confine fra citt\ue0 e campagna. Scopo del lavoro \ue8 stata la definizione di un percorso metodologico originale per la pianificazione di un waterfront extraurbano con funzione ecologica e ricreativa, percorso volto a definire la localizzazione pi\uf9 adeguata delle funzioni e delle attivit\ue0 previste in modo da valorizzare le risorse del territorio rurale ancora presenti nelle aree di frangia urbana. La metodologia si \ue8 basata sull\u2019utilizzo delle informazioni territoriali disponibili nel sistema informatico territoriale della Regione Lombardia ed \ue8 quindi utilizzabile su larga scala. Le fasi di valutazione delle risorse e di pianificazione, condotte con gli strumenti propri dell\u2019analisi di rete, hanno permesso, da un lato, di individuare con sufficiente rapidit\ue0 i potenziali corridoi basandosi sugli usi del suolo attuali dando cos\uec concretezza al tema delle reti ecologiche, e dall\u2019altro, di affrontare il tema dei percorsi ciclopedonali ad una scala superiore rispetto a quella comunale. La validazione del metodo \ue8 avvenuta attraverso la sua applicazione al tratto del fiume Lambro compreso fra il Parco di Monza e la citt\ue0 di Milano
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