6,364 research outputs found
Temperature dependent dynamic and static magnetic response in magnetic tunnel junctions with Permalloy layers
Ferromagnetic resonance and static magnetic properties of CoFe/Al2O3/CoFe/Py
and CoFe/Al2O3/CoFeB/Py magnetic tunnel junctions and of 25nm thick
single-layer Permalloy(Py) films have been studied as a function of temperature
down to 2K. The temperature dependence of the ferromagnetic resonance excited
in the Py layers in magnetic tunnel junctions shows knee-like enhancement of
the resonance frequency accompanied by an anomaly in the magnetization near
60K. We attribute the anomalous static and dynamic magnetic response at low
temperatures to interface stress induced magnetic reorientation transition at
the Py interface which could be influenced by dipolar soft-hard layer coupling
through the Al2O3 barrier
Magnetoelectric Effect in Type-II Quantum Cone Induced by Donor Impurity
We consider a model of donor centered at the base of a type-II nanocone, in which the excessive electron, released from the donor, is located within a narrow tube-shaped shell exterior region around the cone lateral surface. By solving the one-electron Schrödinger equation we analyze the alteration of the spatial probability distribution of the electron, the period of the Aharonov-Bohm oscillations of the energy levels, and the electric and magnetic moments induced by external electric and magnetic fields, applied along the symmetry axis. We show that the diamagnetic confinement provided by the magnetic field forces the electron to climb along the cone’s border, inducing the electric polarization of the structure. Similarly, the external electric field, which pushes the electron toward cone’s bottom, changes the order of the energy levels with different magnetic momenta varying the magnetic polarization of the structure. Our theoretical analysis reveals a new possibility for the coupling between the polarization and magnetization arising from the quantum-size effect in type-II semiconductor nanocones
New approaches on the study of the psychometric properties of the STAI
The main purpose of this study was to analyze the psychometric properties of the State-Trait Anxiety Inventory (STAI1). Previous studies have indicated different factor solutions. Nevertheless, there is still a lack of consensus about the best dimensional model of STAI scores.The sample consisted of 417 participants, composed of 387 (29.71% male) healthy participants (comparison group: M=35.5 years; SD=8.40), and 30 (36.66% male) patient (clinical group M=35.8 years; SD=12.94).The internal consistency evaluated through Ordinal Alpha was good, 0.98 and 0.94 in the non-clinical and the clinical samples, respectively. Test-retest reliability (two weeks) for Total Score was 0.81 for the non-clinical subsample, and 0.93 for the clinical subsample. Confirmatory factor analyses supported both a four factor model and bifactor model. Also, STAI scores showed statistically significant correlations with Burns Anxiety Inventory (Burns-A) scores. Furthermore, results showed statistically significant differences in the mean scores of the STAI between the clinical and the non-clinical subsamples.The psychometric properties of the STAI were adequate. The present study contributes to better understand the STAI structure through the comparison of new approaches in the study of the STAI internal structure. The results found may contribute in the efforts to improve the evaluation and identification of anxiety symptoms and disorders
Photodynamic inactivation of Lasiodiplodia theobromae: lighting the way towards an environmentally friendly phytosanitary treatment
The fungus Lasiodiplodia theobromae is one of the main causal agents of trunk canker and dieback of grapevine. The objective of this work was to evaluate the efficiency of photodynamic inactivation (PDI) of L. theobromae with synthetic and natural photosensitizers and irradiation with either sunlight or artificial photosynthetically active radiation. Although the growth of the mycelium could not be completely prevented with natural sunlight irradiation, phenothiazine dyes (methylene blue, MB; toluidine blue O, TBO), riboflavin and a cationic porphyrin (Tetra-Py+-Me) caused complete inhibition under continuous irradiation with artificial light. Free radicals were the main cytotoxic agents in the PDI with MB, indicating the predominance of the type I mechanism. PDI with MB or Tetra-Py+-Me may represent a promising approach for the sanitation of vine material in greenhouse nurseries, in order to reduce the risk of infection upon grafting.publishe
Cryptovalsa ampelina on Grapevines in N.E. Spain : Identification and Pathogenicity
Surveys conducted in diseased vineyards in Catalonia (N.E. Spain) showed that Cryptovalsa ampelina
was very abundant on pruned canes, although it was isolated occasionally from necrotic wood of living plants. Identification
of C. ampelina from the pruned canes was based on the morphology of the teleomorph. Its polysporous asci
and pigmented allantoid ascospores distinguish it from Eutypa lata, the causal agent of eutypiose. However, cultures
of C. ampelina are practically indistinguishable from cultures of other diatrypaceous species, therefore a PCR-based
test was developed to identify cultures isolated from cankered wood. The designed species-specific primer pair (Camp-
1/Camp-2R) allowed for the unambiguous identification of C. ampelina in all tested cases involving cultures of
diatrypaceous fungi. Additionally, the specificity of the primer pair to C. ampelina was confirmed by testing it on the
host and on several other fungi known to occur on grapevine, namely species in the genera Botryosphaeria, Fomitiporia,
Phaeoacremonium, Phaeomoniella and Phomopsis. The pathogenicity of C. ampelina on grapevine was confirmed
through the observation of significant vascular lesions in artificial inoculations of grapevine plants, but the low
frequencies of both mycelium reisolation and wound canker extension would suggest a low virulence for this fungus.
Although C. ampelina does not appear to be a major pathogen of grapevine, its implication as a contributing factor to
the decline of grapevines should deserve further investigations
Flavored CP asymmetries for type II seesaw leptogenesis
A novel contribution to the leptonic CP asymmetries in type II seesaw leptogenesis scenarios is obtained for the cases in which flavor effects are relevant for the dynamics of leptogenesis. In the so-called flavored leptogenesis regime, the interference between the tree-level amplitude of the scalar triplet decaying into two leptons and the one-loop wave function correction with leptons in the loop, leads to a new nonvanishing CP asymmetry contribution. The latter conserves total lepton number but violates lepton flavor. Cases in which this novel contribution may be dominant in the generation of the baryon asymmetry are briefly discussed
Clinical Characteristics and Risk Factors For Mortality During the \u27First Wave\u27 of COVID-19 In Reynosa, Tamaulipas
Background: The COVID-19 pandemic has impacted public health in Mexico. As of February 2020, there have been at least four waves of contagion that resulted in 5.82 million positive cases and more than 325 thousand deaths. At the beginning of the COVID-19 pandemic, hospital and population-based information was available, frequently with non-specific symptoms. Little was known about the risk factors for mortality in specific conditions. We described the clinical characteristics of patients with COVID-19 in Reynosa, Tamaulipas during 2020 and identified the risk factors for mortality.
Methods: The COVID-19 cases registered from March to November 2020 in Reynosa were divided into survivors and non-survivors. The study had a retrospective cohort design. Data was obtained from the platform of the Respiratory Disease Surveillance System (SISVER), belonging to the National Epidemiological Surveillance System (SINAVE) of the Mexican Ministry of Health (https://sinave.gob.mx/). The variables considered were the age and gender of each patient. Twenty-five symptoms were included (fever, cough, headache, myalgia, arthralgia, among others); the outcome variable was the detection of COVID-19. Associated comorbidities were diabetes, obesity, hypertension, among others. The outcome variable was mortality. Data were analyzed using χ2 tests, Mann-Whitney tests, principal component analysis, and the Cox regression model.
Results:The highest number of COVID-19 cases and deaths was observed in July, in men between 36-40 years old. The most frequent symptoms (37-51%) were headache, fever, cough, myalgia, and arthralgia. Clinical characteristics between survivors and non-survivors were significant (P
Conclusions: The most frequent symptoms in positive COVID-19 patients in Reynosa during 2020 were headache, fever, cough, myalgia, and arthralgia. Age, gender and diabetes, hypertension, heart disease, COPD, and CKD increase mortality. The factors with the highest risk of death were age over 80 years, admitted to the ICU or intubated
Minimal lepton flavor violating realizations of minimal seesaw models
We study the implications of the global U(1)R symmetry present in minimal
lepton flavor violating implementations of the seesaw mechanism for neutrino
masses. In the context of minimal type I seesaw scenarios with a slightly
broken U(1)R, we show that, depending on the R-charge assignments, two classes
of generic models can be identified. Models where the right-handed neutrino
masses and the lepton number breaking scale are decoupled, and models where the
parameters that slightly break the U(1)R induce a suppression in the light
neutrino mass matrix. We show that within the first class of models,
contributions of right-handed neutrinos to charged lepton flavor violating
processes are severely suppressed. Within the second class of models we study
the charged lepton flavor violating phenomenology in detail, focusing on mu to
e gamma, mu to 3e and mu to e conversion in nuclei. We show that sizable
contributions to these processes are naturally obtained for right-handed
neutrino masses at the TeV scale. We then discuss the interplay with the
effects of the right-handed neutrino interactions on primordial B - L
asymmetries, finding that sizable right-handed neutrino contributions to
charged lepton flavor violating processes are incompatible with the requirement
of generating (or even preserving preexisting) B - L asymmetries consistent
with the observed baryon asymmetry of the Universe.Comment: 21 pages, 4 figures; version 2: Discussion on possible generic models
extended, typos corrected, references added. Version matches publication in
JHE
Tunable room-temperature spin galvanic and spin Hall effects in van der Waals heterostructures
Spin-orbit coupling stands as a powerful tool to interconvert charge and spin
currents and to manipulate the magnetization of magnetic materials through the
spin torque phenomena. However, despite the diversity of existing bulk
materials and the recent advent of interfacial and low-dimensional effects,
control of the interconvertion at room-temperature remains elusive. Here, we
unequivocally demonstrate strongly enhanced room-temperature spin-to-charge
(StC) conversion in graphene driven by the proximity of a semiconducting
transition metal dichalcogenide(WS2). By performing spin precession experiments
in properly designed Hall bars, we separate the contributions of the spin Hall
and the spin galvanic effects. Remarkably, their corresponding conversion
effiencies can be tailored by electrostatic gating in magnitude and sign,
peaking nearby the charge neutrality point with a magnitude that is comparable
to the largest efficiencies reported to date. Such an unprecedented
electric-field tunability provides a new building block for spin generation
free from magnetic materials and for ultra-compact magnetic memory
technologies.Comment: 13 pages, 4 figure
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