465 research outputs found

    Kondo effect in quantum dots coupled to ferromagnetic leads with noncollinear magnetizations

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    Non-equilibrium Green's function technique has been used to calculate spin-dependent electronic transport through a quantum dot in the Kondo regime. The dot is described by the Anderson Hamiltonian and is coupled either symmetrically or asymmetrically to ferromagnetic leads, whose magnetic moments are noncollinear. It is shown that the splitting of the zero bias Kondo anomaly in differential conductance decreases monotonically with increasing angle between magnetizations, and for antiparallel configuration it vanishes in the symmetrical case while remains finite in the asymmetrical one.Comment: 4 pages, 3 figure

    Health literacy: impact on the health of HIV-infected individuals.

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    Health literacy is known to affect vulnerable communities such as persons living with HIV/AIDS. The purpose of this review was to provide a current summary of research on the impact of health literacy on the health of persons living with HIV/AIDS and to address future areas of need. Contemporary studies focused on expanding the reach of health literacy in HIV/AIDS to retention in HIV care, use of technology for assessing and intervening to improve health literacy, and health literacy across the globe, for example. A number of studies did not find health literacy to explain health behaviors whereas other studies supported such a relationship. Future issues relevant to health literacy in HIV/AIDS include the aging of the HIV population and associated comorbidities, studies to understand the role of health literacy in specific populations affected by HIV/AIDS, and the continued need to refine the definition and measurement of health literacy

    Ekonomiczna wartość danych a ochrona użytkowników-konsumentów na cyfrowych platformach Glosa do wyroku Okręgowego Sądu Administracyjnego w Lacjum z dnia 10 stycznia 2020 r., nr 261/2020

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    Przedmiotem niniejszej glosy jest analiza orzeczenia Okręgowego Sądu Administracyjnego wydanego w odniesieniu do decyzji włoskiego urzędu antymonopolowego (Autorità Garante della Concorrenza e del Mercato) nakładającej na spółkę Facebook karę 10 mln euro w związku z naruszaniem przez przedsiębiorcę prawa konsumenckiego. Artykuł koncentruje się przede wszystkim na ekonomicznej wartości danych osobowych oraz możliwości ich gospodarczego wykorzystywania przez podmioty cyfrowe. Rozważania dokonywane są w oparciu o unijne oraz krajowe przepisy znajdujące zastosowanie w odniesieniu do danych osobowych, z uwzględnieniem najnowszych zmian legislacyjnych w tej materii. Autorzy wskazują, że choć dane osobowe mają nietowarowy charakter, umożliwianie ich przetwarzania może być traktowane jako świadczenie niepieniężne użytkownika na rzecz platformy-przedsiębiorcy, a co za tym idzie powinno podlegać ochronie na podstawie krajowych regulacji dotyczących stosunków między przedsiębiorcą a konsumentem

    Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

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    Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses

    Resolution of diaschisis contributes to early recovery from post-stroke aphasia

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    Diaschisis is a phenomenon observed in stroke that is defined as neuronal dysfunction in regions spared by the infarction but connected to the lesion site. We combined lesion network mapping and task-based functional MRI in 71 patients with post-stroke aphasia to investigate, whether diaschisis and its resolution contribute to early loss and recovery of language functions. Language activation acquired in the acute, subacute and chronic phase was analyzed in compartments with high and low normative resting-state functional connectivity to the lesion site on an individual basis. Regions with high compared to regions with low lesion connectivity showed a steeper increase in language reactivation from the acute to the subacute phase. This finding is compatible with the assumption of resolution of diaschisis. Additionally, language performance in the subacute phase and improvement from the subacute to the chronic phase significantly correlated with the diaschisis effect and its resolution, respectively, suggesting a behavioral relevance of this effect. We therefore assume that undamaged but functionally connected regions become dysfunctional due to missing input from the lesion contributing to the aphasic deficit. Since these regions are structurally intact, dysfunction resolves over time contributing to the rapid early behavioral improvement observed in aphasic stroke patients. Our results demonstrate that diaschisis and its resolution might be a relevant mechanism of early loss and recovery of language function in acute stroke patients

    Macrofauna-sized foraminifera in epibenthic sledge samples from five areas in the eastern Clarion-Clipperton Zone (equatorial Pacific)

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    Benthic foraminifera cannot be sampled adequately using a single device. Smaller taxa are best collected using multicorers, the larger with box corers, but towed devices (dredges, trawls and epibenthic sledges) also retain many larger species. Here, we describe macrofaunal (>300 µm) foraminiferal assemblages obtained using an epibenthic sledge (EBS) in the Clarion-Clipperton Zone (eastern equatorial Pacific), a region hosting seafloor deposits of polymetallic nodules. Twelve EBS samples were collected in four areas licenced for exploration by the International Seabed Authority (ISA) to German, IOM, Belgium and French contractors, and to APEI-3, one of the protected Areas of Special Scientific Interest designated by the ISA. We recognised 280 morphospecies among 1954 specimens, with between 74 (IOM) and 121 (Belgium) in particular areas. Most (92.7%) were single-chambered monothalamids, of which 75 species (26.8%) belonged to the Komokioidea (‘komoki’), 47 (16.8%) to branched and unbranched tubes, 33 (11.8%) to chain-like and 32 (11.4%) to various ‘komoki-like’ forms. Fragments of megafaunal xenophyophores represented 21 species (7.50%), including Spiculammina delicata, previously reported only from the Russian area. Rarefaction curves and sample coverage completeness curves suggest that only a fraction of the macrofaunal foraminiferal diversity had been sampled. The occurrence of 71.8% of species in 1-2 of the 12 samples and 84.9% in 1-3 of the samples was a likely result of substantial undersampling. Dissimilarity in species composition between areas was very high: 64.2% (German vs IOM area) to 86.9% (German area vs APEI-3). Similarity within a single area was quite low: 29.1% (German) to 45.1% (IOM). In multidimensional scaling (MDS) plots, the APEI-3 area was clearly distinct in terms of faunal composition from all other areas, the French area somewhat separated from the German, IOM and Belgium areas, with the German and IOM samples being the most similar. These patterns may reflect the geographical separation of the French and APEI-3 areas and their location in deeper, more oligotrophic waters. Our study demonstrates that EBS samples from the eastern CCZ are a rich source of novel foraminiferal taxa, particularly light, easily resuspended komoki, providing a valuable perspective on foraminiferal biodiversity

    9 Odczucia chorych na nowotwór narządu rodnego otrzymujących różne formy brachyterapii

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    Rak to choroba otoczona nimbem grozy, pełnią Ięku i ludzką niewiedzą. Z rozpoznaniem tej choroby każdorazowo łączy się poddanie bardzo specyficznym metodom leczenia, których wyobrażenie sobie przez pacjentów niejednokrotnie przerasta utarte stereotypy. U kobiet z rozpoznaniem raka szyjki macicy i raka błony śluzowej macicy proponowaną formą leczenia jest radioterapia składająca się z teleterapii i brachyterapii. Stosowane rodzaje brachyterapii w Wielkopolskim Centrum Onkologii to metody afterloading – Selektron LDR i HDR. U większości pacjentek przed przystąpieniem do leczenia występuje wysoki poziom Ięku, który w znacznej mierze burzy racjonalne sposoby radzenia sobie w sytuacjach trudnych.Celem pracy było przeanalizowanie odczuć i zachowań chorych w związku z czekającą ict brachyterapią.Badaniem objęto grupę 72 chorych na raka szyjki macicy i raka błony śluzowej macicy, leczonych od stycznia do czerwca 2000 roku na Oddziale Radioterapii Ginekologicznej Wielkopolskiego Centrum Onkologii w Poznaniu. Metodą badania była rozmowa psychologiczna i obserwacja.Na podstawie uzyskanych wyników stwierdzono:-żródłem informacji na temat proponowanego sposobu leczenia są najczęściej inne chore, które to leczenie już przeszły lub przebywają na oddziale stosunkowo długo i posiadają własną opinię na ten temat,-przekazywane przez inne chore informacje Są subiektywne w opisie i ocenie przeżyć, które poprzez silne emocje oddziałują na wyobrażnię,-rozmowy na temat brachyterapii z lekarzem nie wpływają uspokajająco na pacjentki,-największą wyobrażalną trudnością dla chorych związaną z założeniami Selektronu-LDR wydaje się trwające ponad 20 godzin leżenie w stałej pozycji, bez możliwości jej zmiany, ból, ograniczona samodzielność, przebywanie długiego czasu w zamkniętych pomieszczeniach, z dala od innych pacjentek-druga aplikacja Selektronu-LDR jest w ocenie pacjentek zdecydowanie trudniejszym doświadczeniem, aniżeli pierwsza,-pacjentki opisują swój wielki niepokój przed pierwszą aplikacją HDR-u, który nie znajduje pokrycia w rzeczywistości, problemem dla chorych jest to, że aplikacje odbywają się w zamkniętym pomieszczeniu, zlokalizowanym w bunkrze, w którym znajduje się aparat do teleterapii,-metoda HDR w porównaniu z Selektronem-LDR jest metodą leczenia bardziej preferowaną ze względu na krótki czas aplikacji,-indywidualnie każda chora ocenia brachyterapię jako najtrudniejszy sposób leczenia, jednakże możliwy do zaakceptowania ze względu na istniejąca nadzieję i wiarę w jej skuteczność.WnioskiBrachyterapia jest taką formą leczenia, która do momentu poddania się jej nigdy nie zyskuje w opinii chorych aprobaty. Obie metody – Selektron-LDR i HDR odbierane Są przez pacjentki jako trudne, ale w ich przekonaniu bardzo skuteczne

    High concordance between mental stress-induced and adenosine-induced myocardial ischemia assessed using SPECT in heart failure patients:Hemodynamic and biomarker correlates

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    Mental stress can trigger myocardial ischemia, but the prevalence of mental stress–induced ischemia in congestive heart failure (CHF) patients is unknown. We characterized mental stress–induced and adenosine-induced changes in myocardial perfusion and neurohormonal activation in CHF patients with reduced left-ventricular function using SPECT to precisely quantify segment-level myocardial perfusion. Methods: Thirty-four coronary artery disease patients (mean age ± SD, 62 ± 10 y) with CHF longer than 3 mo and ejection fraction less than 40% underwent both adenosine and mental stress myocardial perfusion SPECT on consecutive days. Mental stress consisted of anger recall (anger-provoking speech) followed by subtraction of serial sevens. The presence and extent of myocardial ischemia was quantified using the conventional 17-segment model. Results: Sixty-eight percent of patients had 1 ischemic segment or more during mental stress and 81% during adenosine. On segment-by-segment analysis, perfusion with mental stress and adenosine were highly correlated. No significant differences were found between any 2 time points for B-type natriuretic peptide, tumor necrosis factor-α, IL-1b, troponin, vascular endothelin growth factor, IL-17a, matrix metallopeptidase-9, or C-reactive protein. However, endothelin-1 and IL-6 increased, and IL-10 decreased, between the stressor and 30 min after stress. Left-ventricular end diastolic dimension was 179 ± 65 mL at rest and increased to 217 ± 71 after mental stress and 229 ± 86 after adenosine (P < 0.01 for both). Resting end systolic volume was 129 ± 60 mL at rest and increased to 158 ± 66 after mental stress (P < 0.05) and 171 ± 87 after adenosine (P < 0.07), with no significant differences between adenosine and mental stress. Ejection fraction was 30 ± 12 at baseline, 29 ± 11 with mental stress, and 28 ± 10 with adenosine (P = not significant). Conclusion: There was high concordance between ischemic perfusion defects induced by adenosine and mental stress, suggesting that mental stress is equivalent to pharmacologic stress in eliciting clinically significant myocardial perfusion defects in CHF patients. Cardiac dilatation suggests clinically important changes with both conditions. Psychosocial stressors during daily life may contribute to the ischemic burden of CHF patients with coronary artery disease. Keywords: heart failure, mental stress, ischemia, myocardial perfusion, adenosine, single-photon emission computed tomograph

    Spin effects in single electron tunneling

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    An important consequence of the discovery of giant magnetoresistance in metallic magnetic multilayers is a broad interest in spin dependent effects in electronic transport through magnetic nanostructures. An example of such systems are tunnel junctions -- single-barrier planar junctions or more complex ones. In this review we present and discuss recent theoretical results on electron and spin transport through ferromagnetic mesoscopic junctions including two or more barriers. Such systems are also called ferromagnetic single-electron transistors. We start from the situation when the central part of a device has the form of a magnetic (or nonmagnetic) metallic nanoparticle. Transport characteristics reveal then single-electron charging effects, including the Coulomb staircase, Coulomb blockade, and Coulomb oscillations. Single-electron ferromagnetic transistors based on semiconductor quantum dots and large molecules (especially carbon nanotubes) are also considered. The main emphasis is placed on the spin effects due to spin-dependent tunnelling through the barriers, which gives rise to spin accumulation and tunnel magnetoresistance. Spin effects also occur in the current-voltage characteristics, (differential) conductance, shot noise, and others. Transport characteristics in the two limiting situations of weak and strong coupling are of particular interest. In the former case we distinguish between the sequential tunnelling and cotunneling regimes. In the strong coupling regime we concentrate on the Kondo phenomenon, which in the case of transport through quantum dots or molecules leads to an enhanced conductance and to a pronounced zero-bias Kondo peak in the differential conductance.Comment: topical review (36 figures, 65 pages), to be published in J. Phys.: Condens. Matte
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