Prospect Theory predicts that people tend to be more risk seeking if their reference point is perceived as a loss and more risk averse when the reference point is perceived as a gain. In line with this prediction, Franken, Georgieva, Muris and Dijksterhuis (2006) showed that young adults who had a prior experience of monetary gains make more safe choices on subsequent decisions than subjects who had an early experience of losses. There are no experimental studies on how experiencing prior gains and losses differently influences young and older adults on a subsequent decision-making task (the Iowa Gambling Task). Hence, in the current paper, adapting the methodology employed by Franken et al.’s (2006), we intended to test the generality of their effect across the life span. Overall, we found that subjects who experienced prior monetary gains or prior monetary losses did not display significant differences in safe/risky choices on subsequent performance in the Iowa Gambling task. Furthermore, the impact of prior gains and losses on risky/safe card selection did not significantly differ between young and older adults. These results showed that the effect found in the Franken et al.’s study (2006) is limited in its generality.

Este artigo analisa aspectos do patriarcalismo presentes em obras de Machado de Assis. O objetivo é evidenciar a crítica a uma cultura patriarcal idealizada, segundo padrões de uma antiguidade clássica difundida no século XIX. Trata-se, portanto, da anatomia de uma farsa, oculta na retórica refinada de representantes da oligarquia escravocrata. Machado de Assis revela, em seus escritos, o ethos da oligarquia que estruturou a sociedade brasileira do anos 1800.

The COVID-19 pandemic is a global traumatic experience for citizens, especially during sensitive time windows of heightened plasticity such as pregnancy and neonatal life. Pandemic-related stress experienced by mothers during pregnancy may act as an early risk factor for infants’ regulatory capacity development by altering maternal psychosocial well-being (e.g., increased anxiety, reduced social support) and caregiving environment (e.g., greater parenting stress, impaired mother–infant bonding). The aim of the present longitudinal study was to assess the consequences of pandemic-related prenatal stress on infants’ regulatory capacity. A sample of 163 mother–infant dyads was enrolled at eight maternity units in northern Italy. They provided complete data about prenatal stress, perceived social support, postnatal anxiety symptoms, parenting stress, mother–infant bonding, and infants’ regulatory capacity at 3 months of age. Women who experienced emotional stress and received partial social support during pregnancy reported higher anxious symptoms. Moreover, maternal postnatal anxiety was indirectly linked to the infants’ regulatory capacity at 3 months, mediated by parenting stress and mother–infant bonding. Dedicated preventive interventions should be delivered to mothers and should be focused on protecting the mother–infant dyad from the detrimental effects of pandemic-related stress during the COVID-19 healthcare emergency.

Mood disorders are characterized by manic and depressive episodes alternating with normal mood. While social function is heavily impaired during episodes of illness, there are conflicting opinions about inter-episode function. The present paper focuses on self-esteem and social adjustment in remitted mood disorders patients.

Patients with mood disorders (99 bipolar and 86 major depressive subjects, in remission) were compared with a group of 100 control subjects. The self-esteem scale (SES) and the social adjustment scale (SAS) were used to measure self-esteem and social adjustment, respectively, in both groups of subjects.

Patients with mood disorder exhibited worse social adjustment and lower self-esteem than control subjects.These results strongly confirm previous observations of poor inter-episode function in patients with mood disorder.

Objectives: The aim of the present study was to investigate “Proactive-Adjustment hypothesis” (PA) during the Stop Signal Task (SST). The PA is implied in the highly inconsistent literature, and it deals with the role of response inhibition (RI) in obsessive-compulsive disorder (OCD). This hypothesis assumed that participants would balance stopping and going by adjusting the response threshold (RT) in the go task. We verified whether the PA strategy was also implemented in our clinical group. Methods: To reach this goal, we analyzed SST performances in a group of 36 patients with OCD and 36 healthy controls (HCs). To identify different participants’ behaviors during the task, without preconceived notions regarding the diagnosis, we performed a cluster analysis. Furthermore, we analyzed the influence of drug therapy and we investigated whether the rule and reversal acquisition investigated with the Intra-Extra Dimensional Set Shift, differed in the two clusters. Results: We did not find any difference relative to the number of patients with OCD and HCs included in the two clusters. Furthermore, we found that only Not Proactive participants performed the task as fast as possible, while Proactive participants consistently slowed down their RTs and showed a lower number of Direction Errors, higher Stop Signal Delay, and worse cognitive flexibility. Conclusions: Our results show that among patients with OCD the use of PA is changeable and does not differ from HCs. This finding supports the idea that the RI heterogeneity concerning patients with OCD could be related to PA. (JINS, 2018, 24, 1–12)

III-nitrides (III-Ns) semiconductors and their alloys have shown in the last few years high potential for interesting applications in photonics and electronics. III-Ns based heterostructures (HS) have been under wide investigation for different applications such as high frequency transistors, ultraviolet photodetector, light emitters etc. In the present contribution a III-Ns based heterostructure, in particular the nearly lattice matched Al1-xInxN/AlN/GaN HS will be discussed. The formation of the two dimensional electron gas (2DEG), its origin, its electrical and optical properties, the confined subband states in the well and its effect on the conduction mechanisms have been studied. Moreover, extended defects and their effect on the degradation phenomena of the 2DEG have been analyzed.

Organic single crystals offer the interesting and unique opportunity to investigate the intrinsic electrical behaviour of organic materials, excluding hopping phenomena due to grain boundaries and structural imperfections. Their structural asymmetry permits also to investigate the correlation between their three-dimensional order and their charge transport characteristics. Here we report on millimeter-sized, solution-grown organic single crystals, based on 4-hydroxycyanobenzene (4HCB), which exhibit three-dimensional anisotropic electrical properties along the three crystallographic axes a, b (constituting the main crystal flat face) and c (the crystal thickness), measured over several different samples. The carrier mobility was determined by means of space charge limited current (SCLC) and air-gap field effect transistors fabricated with 4HCB single crystals and the measured value well correlate with the structural packing anisotropy of the molecular crystal. A differential analysis of SCLC curves allowed to determine the distribution and the concentration of the dominant electrically active density of states within the gap.

We studied the anisotropic charge transport properties of solution-grown organic single crystals based on a dipolar molecule 4HCB (4-hydroxy-cyanobenzene) by electrical transport measurements, current-voltage and space charge limited current (SCLC), and by X-ray diffraction analyses.

Optical excitation differently affects the flow of charge carriers along the two main planar crystal axis, altering the charge transport anisotropy induced by the molecular π-orbitals stacking. We attribute this behaviour to the presence of an intrinsic molecular dipole and to its different orientation within the crystal lattice. The anisotropy of transport along the three crystallographic directions has been assessed by electrical characterization and correlated to the crystal molecular packing as determined by X-ray analyses.

We investigated the electronic levels of defects introduced in 4H-SiC α-particle detectors by irradiation with 1 MeV neutrons up to a fluence equal to 8x1015 n/cm2. As well, we investigated their effect on the detector radiation hardness. This study was carried out by deep level transient spectroscopy (DLTS) and photo-induced current transient spectroscopy (PICTS). As the irradiation level approaches fluences in the order of 1015 n/cm2, the material behaves as highly resistive due to a very great compensation effect but the diodes are still able to detect with a acceptably good charge collection efficiency (CCE) equal to 80%. By further increasing fluence, CCE decreases reaching the value of ≈ 20% at fluence of 8x1015 n/cm2.

The dominant peaks in the PICTS spectra occur in the temperature range [400, 700] K. Enthalpy, capture cross-section and order of magnitude of the density of such deep levels were calculated. In the above said temperature range the deep levels associated to the radiation induced defects play the key role in the degradation of the CCE. Two deep levels at Et = 1.18 eV and Et = 1.50 eV are likely to be responsible of such dramatic decrease of the charge collection efficiency. These levels were reasonably associated to an elementary defect involving a carbon vacancy and to a defect complex involving a carbon and a silicon vacancy, respectively.

We present a combined Capacitance-Voltage (C-V), Deep Level Transient Spectroscopy (DLTS) and Photocurrent (PC) study of short-term instabilities of InGaN/GaN LEDs submitted to forward current aging tests at room temperature. C-V profiles detect changes consisting in apparent doping and/or charge concentration increase within the quantum wells. This increase is correlated to dramatic modifications in the DLTS spectrum when the reverse bias and filling pulse are properly adjusted in order to probe the quantum well region. The new distribution of the electronic levels detected by DLTS could explain the observed decrease in the light emission efficiency [1,2] of the device, as the deep levels generated during the stress may provide alternative recombination paths for free carriers. The photocurrent spectra do not change in shape during stress, although their amplitude slightly decreases. This is related to a decrease of the device yield, in this photodetector configuration, with increasing aging time. Thus, we can suggest that the introduction of new defect levels in the bulk material lowers the free carrier mobility.

This paper reports on first results obtained on GaN epitaxial layer grown on a single wafer with a lateral variation in defect density. The chemically homogeneous GaN epitaxial layer was deposited by metalorganic chemical vapour deposition onto a specially prepared buffer layer. A chemical gradient in the nitrogen contents of the precursor flux was induced during the growth of the GaN buffer layer. This condition leads a corresponding gradient of the dislocation density within the epilayer. The electrical and optical properties of the GaN epilayer have been analysed by means of electron beam induced current, photoluminescence and photocurrent techniques. All our measurements reveal lateral gradients in the epilayer properties as concern (i) the density of recombining centres in the GaN film and (ii) their recombination activity, both radiative and nonradiative. This paper shows that a proper combination of beam based techniques can contribute to the detailed analysis of the well know yellow luminescence band which in the GaN epilayer here investigated consist of four well distinct peaks.

Self heating during long-term DC-aging is found to be responsible for the degradation of the electrical and optical characteristics of blue p-GaN/p-AlGaN/InGaN/n+-GaN/SiC LEDs. Electroluminescence and Cathodoluminescence studies reveal an additional large optical band, not observed in unstressed devices, on the p-type side of the LEDs. Deconvolution procedures shows the band, peaked at about 3.1 eV, is due to three main emissions at 2.93, 3.08 and 3.23 eV. Deep Level Transient Spectroscopy reveals the presence of four traps for majority carriers in p-type GaN. A comparison with the optical spectra suggests three of them (at 0.12, 0.22 and about 0.5 eV) are responsible for the additional emissions after stress, while a further trap at 1.21 eV is considered non-radiative in nature. A thermally activated mechanism inducing the dissociation of native Mg-H complexes and the subsequent formation of metastable Mg-H2 complexes is considered responsible for the LED degradation. The hypothesis is supported by high power electron beam irradiation during Cathodoluminescence studies which induced a complete disappearance of the band at 3.1 eV as a consequence of the dissociation under energetic electron beam of the metastable Mg-H2 complexes.