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Three experimental methods of nonlinear characterization of elastic behaviour are compared, based upon constant voltage, constant current and constant frequency respectively. Equivalence between them is shown, and implementation of the last one is described in detail. The best way to describe nonlinear behaviour is to look at the alteration of the electrical impedance as a function of the current level, around the resonance frequency. By taking this description, we are able to compute the onset of hysteresis phenomena. Between the nonlinear increment of the reactance X and the resistance R appears a fairly linear relationship, while the quantities of X and R depend on the motional current through a fractional power function. In order to avoid the overheating inherent to high signal measurement, an excitation by bursts is proposed, and electrical response and velocity, obtained during the steady state, has been treated afterwards. This method has been applied to hard and soft PZT ceramics. Elastic electrical and piezoelectric behaviours have been compared, leading to some relations that can be explained by the predominance of the extrinsic processes over the intrinsic onaes.Se describen y comparan tres métodos experimentales de la caracterización no lineal del comportamiento elástico de resonadores, según se mantenga constante la tensión, la corriente o la frecuencia. Se muestra la equivalencia entre los tres métodos, describiendo con detalle la implementación del último. La alteración de la impedancia eléctrica en función de la corriente en el entorno de la frecuencia de resonancia es la mejor forma de expresar el comportamiento no lineal, permitiendo predecir la aparición de histéresis. La relación entre incrementos no lineales de la reactancia X y de la resistencia R se mantiene notablemente lineal, la dependencia de estas magnitudes con la corriente mecánica obedece a una ley potencial de exponente no entero. Para evitar el calentamiento inherente a las medidas con alta señal se propone la excitación por medio de trenes de onda o ráfagas, y el tratamiento posterior de la respuesta eléctrica y de la velocidad v, obtenidas durante el régimen estacionario. El método se aplica adecuadamente tanto a cerámicas PZT blandas como duras. Sus características elásticas se comparan con las características dieléctricas y piezoeléctricas no lineales, obteniendo una relación explicable por el predominio de los mecanismos extrínsecos sobre los intrínsecos.

The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention1–6. The theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization due to time-dependent electric polarization in non-ferromagnetic materials7,8. In simple terms, the coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. Here we provide experimental evidence of room-temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. We resonantly drive the infrared-active soft phonon mode with an intense circularly polarized terahertz electric field and detect the time-resolved magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab initio calculations using self-consistent phonon theory at a finite temperature9, reproduces qualitatively our experimental observations. A quantitatively correct magnitude was obtained for the effect by also considering the phonon analogue of the reciprocal of the Einstein–de Haas effect, which is also called the Barnett effect, in which the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for the control of magnetism, for example, for ultrafast magnetic switches, by coherently controlling the lattice vibrations with light.We demonstrate the emergence of magnetism induced by a terahertz electric field in SrTiO3. [ABSTRACT FROM AUTHOR]

Background: The role of inflammation in mood disorders has received increased attention. There is substantial evidence that cytokine therapies, such as interferon alpha (IFN-alpha), can induce depressive symptoms. Indeed, proinflammatory cytokines change brain function in several ways, such as altering neurotransmitters, the glucocorticoid axis, and apoptotic mechanisms. This study aimed to evaluate the impact on mood of initiating IFN-alpha and ribavirin treatment in a cohort of patients with chronic hepatitis C. We investigated clinical, personality, and functional genetic variants associated with cytokine-induced depression. Methods: We recruited 344 Caucasian outpatients with chronic hepatitis C, initiating IFN-alpha and ribavirin therapy. All patients were euthymic at baseline according to DSM-IV-R criteria. Patients were assessed at baseline and 4, 12, 24, and 48 weeks after treatment initiation using the Patient Health Questionnaire (PHQ), the Hospital Anxiety and Depression Scale (HADS), and the Temperament and Character Inventory (TCI). We genotyped several functional polymorphisms of interleukin-28 (IL28B), indoleamine 2,3-dioxygenase (IDO-1), serotonin receptor-1A (HTR1A), catechol-O-methyl transferase (COMT), glucocorticoid receptors (GCR1 and GCR2), brain-derived neurotrophic factor (BDNF), and FK506 binding protein 5 (FKBP5) genes. A survival analysis was performed, and the Cox proportional hazards model was used for the multivariate analysis. Results: The cumulative incidence of depression was 0.35 at week 24 and 0.46 at week 48. The genotypic distributions were in Hardy-Weinberg equilibrium. Older age (p = 0.018, hazard ratio [HR] per 5 years = 1.21), presence of depression history (p = 0.0001, HR = 2.38), and subthreshold depressive symptoms at baseline (p = 0.005, HR = 1.13) increased the risk of IFNinduced depression. So too did TCI personality traits, with high scores on fatigability (p = 0.0037, HR = 1.17), impulsiveness (p = 0.0200 HR = 1.14), disorderliness (p = 0.0339, HR = 1.11), and low scores on extravagance (p = 0.0040, HR = 0.85). An interaction between HTR1A and COMT genes was found. Patients carrying the G allele of HTR1A plus the Met substitution of the COMT polymorphism had a greater risk for depression during antiviral treatment (HR = 3.83) than patients with the CC (HTR1A) and Met allele (COMT) genotypes. Patients carrying the HTR1A CC genotype and the COMT Val/Val genotype (HR = 3.25) had a higher risk of depression than patients with the G allele (HTR1A) and the Val/Val genotype. Moreover, functional variants of the GCR1 (GG genotype: p = 0.0436, HR = 1.88) and BDNF genes (Val/Val genotype: p = 0.0453, HR = 0.55) were associated with depression. Conclusions: The results of the study support the theory that IFN-induced depression is associated with a complex pathophysiological background, including serotonergic and dopaminergic neurotransmission as well as glucocorticoid and neurotrophic factors. These findings may help to improve the management of patients on antiviral treatment and broaden our understanding of the pathogenesis of mood disorders. [ABSTRACT FROM AUTHOR]

In this study, starting from an observational case of internal gravity waves (IGWs) generated at the top of a drainage flow during the SABLES2006 field campaign, we aim to reproduce the IGWs and their origin through mesoscale meteorological modelling. We used the Weather Research and Forecast (WRF) model with fine horizontal resolution (1 km), testing the model capabilities to simulate the IGWs through a WRF fixed physics package option but two different planetary boundary layer schemes, the Mellor-Yamada-Janjić (MYJ) and the Yonsei University (YSU). The comparison between model simulations and measurements from a 100 m meteorological tower reveals that the MYJ scheme simulation gives much better results, as it better represents the main features of the density current measured by the tower instruments, although the event is predicted to occur sooner than it is observed to occur. The study has also shown the capacity of this scheme to detect the oscillations in temperature and specific humidity generated by the arrival of the density current. In contrast, the YSU scheme captures the arrival of the current on time but it fails to correctly track its properties and therefore it does not reproduce the gravity waves with the current arrival. In addition, wave parameters calculated from model outputs (MYJ) using the wavelet method reveal waves with longer periods and longer wavelengths ( T = 20-22 min and λ = 8-10 km) than those calculated from measurements ( T = 9.2 min and λ = 3.5 km) using the same technique. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

BACKGROUND: Visceral leishmaniasis (VL) caused by Leishmania infantum is a zoonotic disease endemic throughout the Mediterranean basin. The existence of asymptomatic human infection entails the risk of transmission by blood transfusion. STUDY DESIGN AND METHODS: The prevalence of Leishmania infection was studied in 1437 blood donors from the Balearic Islands (Majorca, Formentera, and Minorca) using immunologic (Western blot [WB] and delayed-type hypersensitivity [DTH]), parasitologic (culture), and molecular (nested polymerase chain reaction [PCR]) methods. In addition, the efficiency of leukoreduction by filtration to remove the parasite was tested by nested PCR in the red blood cell (RBC) units. RESULTS: Leishmania antibodies were detected in 44 of the 1437 blood donors tested (3.1%). A sample of 304 donors from Majorca was selected at random. L. infantum DNA was amplified in peripheral blood mononuclear cells (PBMNCs) in 18 of the 304 (5.9%), and cultures were positive in 2 of the 304 (0.6%). DTH was performed on 73 of the 304 donors and was positive for 8 of them (11%). Of the 18 donors with positive L. infantum nested PCR, only 2 were seropositive. All the RBC samples tested (13 of 18) from donors with a positive PBMNC nested PCR yielded negative nested PCR results after leukodepletion. CONCLUSIONS: Cryptic Leishmania infection is highly prevalent in blood donors from the Balearic Islands. DTH and L. infantum nested PCR appear to be more sensitive to detect asymptomatic infection than the serology. The use of leukodepletion filters appears to remove parasites from RBC units efficiently. [ABSTRACT FROM AUTHOR]

Introduction: Admission to an intensive care unit can cause sequelae to both patients and family members. In some countries, the use of diaries is a preventive action., Aim: This research proposes to critically examine the concept of 'Intensive Care Unit Diary' by analysing the current state of the scientific literature to develop a precise conception of this phenomenon in nursing practice, since there are multiple unknowns regarding its use and content., Method: A bibliographic search was carried out in the PubMed, Cochrane Library, Scopus and CINAHL databases in January 2023. The terms used to search for their use and definitions in the databases included Nurse, Concept analysis, Family, Uci Diary, Patient Critical, Intensive Care Unit. We use Wilson's concept analysis, later developed by Walker and Avant., Results: The concept analysis shows that the 'ICU Diary' is a record made in colloquial language by health workers and relatives of the patient admitted to the intensive care unit. Aimed at the patient, with an empathic and reflective style, which offers a narrative of the process, daily life and the conduct or behaviour of the patient during his stay. It is a therapeutic tool led by nurses accepted by patients, families and professionals. Its use benefits the recovery process, reducing post-traumatic stress in family members and patients. It favours communication and the bond between nurses, family members and patients, helping to express feelings and emotions., Conclusions: The concept of 'UCI Diary' is complex. Through Wilson's model, a clarification of the concept has been achieved, creating a starting point for more precise research on this phenomenon and its effects on patients, family members, professionals and the health system., (Copyright © 2023 Sociedad Española de Enfermería Intensiva y Unidades Coronarias (SEEIUC). Published by Elsevier España S.L.U. All rights reserved.)

Recently developed terahertz (THz) two-dimensional coherent spectroscopy (2DCS) is a powerful technique to obtain materials information in a fashion qualitatively different from other spectroscopies. Here, we utilized THz 2DCS to investigate the THz nonlinear response of conventional superconductor NbN. Using broadband THz pulses as light sources, we observed a third-order nonlinear signal whose spectral components are peaked at twice the superconducting gap energy 2Δ. With narrow-band THz pulses, a THz nonlinear signal was identified at the driving frequency Ω and exhibited a resonant enhancement at temperature when Ω=2Δ. General theoretical considerations show that such a resonance can arise only from a disorder-activated paramagnetic coupling between the light and the electronic current. This proves that the nonlinear THz response can access processes distinct from the diamagnetic Raman-like density fluctuations, which are believed to dominate the nonlinear response at optical frequencies in metals. Our numerical simulations reveal that, even for a small amount of disorder, the Ω=2Δ resonance is dominated by the superconducting amplitude mode over the entire investigated disorder range. This is in contrast to other resonances, whose amplitude-mode contribution depends on disorder. Our findings demonstrate the unique ability of THz 2DCS to explore collective excitations inaccessible in other spectroscopies.

Ultrafast optical control of quantum systems is an emerging field of physics. In particular, the possibility of light-driven superconductivity has attracted much of attention. To identify nonequilibrium superconductivity, it is necessary to measure fingerprints of superconductivity on ultrafast timescales. Recently, nonlinear THz third-harmonic generation (THG) was shown to directly probe the collective degrees of freedoms of the superconducting condensate, including the Higgs mode. Here, we extend this idea to light-driven nonequilibrium states in superconducting La 2- x Sr x CuO 4 , establishing an optical pump-THz-THG drive protocol to access the transient superconducting order-parameter quench and recovering on few-picosecond timescales. We show in particular the ability of two-dimensional TH spectroscopy to disentangle the effects of optically excited quasiparticles from the pure order-parameter dynamics, which are unavoidably mixed in the pump-driven linear THz response. Benchmarking the gap dynamics to existing experiments shows the ability of driven THG spectroscopy to overcome these limitations in ordinary pump-probe protocols.

Recent experiments with strong THz fields in unconventional cuprate superconductors have clearly evidenced an increase of the non-linear optical response below the superconducting critical temperature T c . As in the case of conventional superconductors, a theoretical estimate of the various effects contributing to the non-linear response is needed in order to interpret the experimental findings. Here, we report a detailed quantitative analysis of the non-linear THz optical kernel in cuprates within a realistic model, accounting for the band structure and disorder level appropriate for these systems. We show that the BCS quasiparticle response is the dominant contribution for cuprates, and its polarization dependence accounts very well for the third-harmonic generation measurements. On the other hand, the polarization dependence of the THz Kerr effect is only partly captured by our calculations, suggesting the presence of additional effects when the system is probed using light pulses with different central frequencies.

Objective: The Results Centre's (RC) mission is to measure, evaluate and disseminate the results achieved by the different agents of the health system, based on relevant measures. The purpose of this research is to describe the evolution of indicators used in the social and health care network RC (RC-SH), including some indicators sensitive to nursing practice., Method: Observational, descriptive cross-sectional study based on data from 6 RC-SH reports (2013-2018). Indicators including activity carried out, days of stay, achievement of rehabilitation goals, discharge to home, mortality and pressure ulcers are analysed., Results: There was an increase in activity on the different social and health resources and days of stay decrease. Results were heterogeneous between centres. Functional improvement and home discharge showed an increasing trend, while mortality tended to decrease. The prevalence of grade III-IV pressure ulcers was maintained., Conclusions: RC-SH reports have included different indicators to improve the capacity of evaluation and benchmarking for social and health network. These reports provide transparency and accountability in the field and invite further improvement in this sector. Also RC-SH results show that social and health network evolves towards intermediate care with the entry of subacute resources and the greater efficiency of convalescence. The incorporation of indicators sensitive to nursing practice contributes to making nurses and nursing care visible., (Copyright © 2022 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.)

One of the consequences of the COVID-19 lockdowns has been the modification of the air quality in many cities around the world. This study focuses on the variations in pollutant concentrations and how important meteorological conditions were for those variations in Barcelona and the surrounding area during the 2020 lockdown. Boundary-layer height, wind speed, and precipitation were compared between mid-March and April 2016-2019 (pre-lockdown) and the same period in 2020 (during lockdown). The results show the limited influence of meteorological factors on horizontal and vertical dispersion conditions. Compared with the pre-lockdown period, during lockdown the boundary-layer height slightly increased by between 5% and 9%, mean wind speed was very similar, and the fraction of days with rainfall increased only marginally, from 0.33 to 0.34, even though April 2020 was extremely wet in the study area. Variations in nitrogen dioxide ( NO 2 ), particulate matter with a diameter less than 10 μ m (PM10), and ozone ( O 3 ) concentrations over a 10-year period showed a 66% reduction in NO 2 , 37% reduction in PM10, and 27% increase in O 3 at a traffic station in Barcelona. The differences in the daily concentration cycle between weekends and weekdays were heavily smoothed for all pollutants considered. The afternoon NO 2 peak at the traffic station was suppressed compared with the average daily cycle. The analysis of ozone was extended to the regional scale, revealing lower concentrations at rural sites and higher ones in urban zones, especially in Barcelona and the surrounding area. The results presented not only complement previous air quality COVID-19 lockdown studies but also provide insights into the effects of road-traffic reduction., (© The Author(s) 2021.)

The hallmark of superconductivity is the rigidity of the quantum-mechanical phase of electrons, responsible for superfluid behavior and Meissner effect. The strength of the phase stiffness is set by the Josephson coupling, which is strongly anisotropic in layered cuprates. So far, THz light pulses have been used to achieve non-linear control of the out-of-plane Josephson plasma mode, whose frequency lies in the THz range. However, the high-energy in-plane plasma mode has been considered insensitive to THz pumping. Here, we show that THz driving of both low-frequency and high-frequency plasma waves is possible via a general two-plasmon excitation mechanism. The anisotropy of the Josephson couplings leads to markedly different thermal effects for the out-of-plane and in-plane response, linking in both cases the emergence of non-linear photonics across T c to the superfluid stiffness. Our results show that THz light pulses represent a preferential knob to selectively drive phase excitations in unconventional superconductors.

Raman experiments on bulk FeSe revealed that the low-frequency part of the B_{1g} Raman response R_{B1g}(Ω), which probes nematic fluctuations, rapidly decreases below the nematic transition at T_{n}∼85  K. Such behavior is expected when a gap opens up and at a first glance is inconsistent with the fact that FeSe remains a metal below T_{n}. We argue that the drop of R_{B1g}(Ω) can be ascribed to the fact that the nematic order drastically changes the orbital content of low-energy excitations near hole and electron pockets, making them nearly mono-orbital. In this situation, the B_{1g} Raman response gets reduced by the same vertex corrections that enforce charge conservation in the symmetric Raman channel. The reduction holds at low frequencies and gives rise to gaplike behavior of R_{B1g}(Ω). We also show that the enhancement of the B_{1g} Raman response near T_{n} is consistent with the sign change of the nematic order parameter between hole and electron pockets.

Objective: To assess the utility of prophylactic administration of antidepressants in preventing a major depressive episode during antiviral treatment for chronic hepatitis C., Data Sources: A computerized literature search was conducted in MEDLINE, PsycINFO, EMBASE, the Cochrane Library, and ClinicalTrials.gov to locate articles published in any language from the earliest available online year until October 2012, using the following phrase and Boolean logic algorithm: "hepatitis and c and (interferon-alpha OR peginterferon OR (pegylated and interferon)) and (depression OR mood) and (prevention OR prophylactic OR prophylaxis OR antidepressant).", Study Selection: Double-blind, randomized, placebo-controlled trials using antidepressants prophylactically before starting antiviral therapy for chronic hepatitis C were included. At baseline, none of the patients in the trials presented depression (DSM-IV-TR criteria). Using keywords and cross-referenced bibliographies, 144 studies were identified and examined in depth. 137 articles were rejected because inclusion criteria were not met. Finally, 7 studies were included., Data Extraction: Data were extracted independently by 2 investigators. The primary outcome measure was the onset of a major depressive episode during the antiviral treatment. Depressive symptoms, other side effects, and sustained virologic response were also examined. A full review and meta-analysis were performed. Odds ratios (ORs), mean differences, and estimated numbers needed to treat (NNTs) with 95% confidence intervals (CIs) were calculated., Results: 591 patients were randomly assigned to antiviral treatment and another intervention: escitalopram (n = 197), paroxetine (n = 42), citalopram (n = 53), or placebo (n = 299). Selective serotonin reuptake inhibitors (SSRIs), as a group, reduced the incidence of a major depressive episode during antiviral treatment (OR = 0.53; 95% CI, 0.33 to 0.84). The NNT was 12 (95% CI, 7.0 to 37.9). SSRIs reduced depressive symptoms at 24 weeks of treatment (mean difference -2.18; 95% CI, -4.25 to -0.10). With regard to side effects, only dizziness was associated with administration of antidepressants (OR = 2.65; 95% CI, 1.46 to 4.80). There were no differences in sustained virologic response (OR = 1.22; 95% CI, 0.58 to 2.57)., Conclusions: Administration of SSRIs before starting antiviral treatment reduces the incidence of interferon-induced depression, with a relatively moderate prophylactic impact and good tolerability., (© Copyright 2014 Physicians Postgraduate Press, Inc.)

Current treatments of depression include psychological, pharmacological and physical approaches. Pharmacological interventions to treat depression have previously focused on modifying dysfunctional neurotransmitter systems. Overall, these treatments have demonstrated an ability to manage major depression but otucomes continue to be poor in many patients, especially those with long term illness or with previous multiple relapses. This may be due to the fact that depression is a systemic and neuroprogressive illness involving multiple biological pathways such as immunological factors. There is substantial evidence that cytokine therapies induce depressive symptoms in clinical populations. The model of cytokine-induced depression has provided important information relative to the risk factors and biological pathways involved in the etiology of depressive symptoms and, most importantly, the identification and knowledge of these factors has allowed new treatment targets to be explored. When an exogenous cytokine such as interferon-alpha is administered, proinflammatory cytokines are activated, leading to alterations in neurotransmission and endocrine pathways and producing neurotoxicity. Several new treatments for depression acting through pathways other than amine neurotransmission have emerged in recent years. The regulation of the inflammatory response, the decrease in the activity of the hypothalamic-pituitary-adrenal axis and the prevention of neurotoxicity are potential targets for new drugs. Though these drugs are mostly at the proof-of-concept stage, some of them have already shown promising results for the treatment of depression.