Self-Reflections Through a Screen: Self-Identity, Social Media, and Psychological Well-Being

Social media use among emerging adults is assumed to be related to a variety of negative psychological outcomes and has, in recent years, become a widely studied phenomenon (Kim, 2017, Pew Research Center, 2018). Despite the widespread assumption, the results from empirical studies of the effects of social media use on mental health in this population have been inconsistent and inconclusive (Keles et al., 2020, Yang et al., 2021). Several meta-analyses (e.g., Keles et al., 2020) demonstrate these inconsistent results across studies and point to the need to consider individual difference factors when researching this issue. Different self-identity styles have adaptive and maladaptive self-reflective processes which impact how individuals use social media (Berzonsky & Luyckx, 2008). This study examined the role of differences in self-identity styles among emerging adults and how those differences influence the ways emerging adults use social media as important mediators of psychological well-being. Partial support was found for the hypothesis that more negative identity styles (e.g., diffuse and normative styles) were associated with negative social media use (e.g., social comparison and self-disclosure). Stronger support was found for the hypothesis that such negative social media use was associated with higher levels of depression and anxiety

A new Method to Constrain the Iron Abundance from Cooling Delays in Coronal Loops

Recent observations with TRACE reveal that the time delay between the appearance of a cooling loop in different EUV temperature filters is proportional to the loop length, dt_12 ~ L. We model this cooling delay in terms of radiative loss and confirm this linear relationship theoretically. We derive an expression that can be used to constrain the coronal iron enhancement alpha_Fe=A_Fe^cor/A_Fe^Ph relative to the photospheric value as function of the cooling delay dt_12, flux F_2, loop width w, and filling factor q_w < 1. With this relation we find upper limits on the iron abundance enhancement of alpha_Fe < 4.8+/-1.7 for 10 small-scale nanoflare loops, and alpha_Fe < 1.4+/-0.4 for 5 large-scale loops, in the temperature range of T~1.0-1.4 MK. This result supports the previous finding that low-FIP elements, including Fe, are enhanced in the corona. The same relation constitutes also a lower limit for the filling factor, which is q_w > 0.2+/-0.1 and q_w > 0.8+/-0.2 for the two groups of coronal loops.Comment: 2 Figure

Multi-Thread Hydrodynamic Modeling of a Solar Flare

Past hydrodynamic simulations have been able to reproduce the high temperatures and densities characteristic of solar flares. These simulations, however, have not been able to account for the slow decay of the observed flare emission or the absence of blueshifts in high spectral resolution line profiles. Recent work has suggested that modeling a flare as an sequence of independently heated threads instead of as a single loop may resolve the discrepancies between the simulations and observations. In this paper we present a method for computing multi-thread, time-dependent hydrodynamic simulations of solar flares and apply it to observations of the Masuda flare of 1992 January 13. We show that it is possible to reproduce the temporal evolution of high temperature thermal flare plasma observed with the instruments on the \textit{GOES} and \textit{Yohkoh} satellites. The results from these simulations suggest that the heating time-scale for a individual thread is on the order of 200 s. Significantly shorter heating time scales (20 s) lead to very high temperatures and are inconsistent with the emission observed by \textit{Yohkoh}.Comment: Submitted to Ap

Non-equilibrium of Ionization and the Detection of Hot Plasma in Nanoflare-heated Coronal Loops

Impulsive nanoflares are expected to transiently heat the plasma confined in coronal loops to temperatures of the order of 10 MK. Such hot plasma is hardly detected in quiet and active regions, outside flares. During rapid and short heat pulses in rarified loops the plasma can be highly out of equilibrium of ionization. Here we investigate the effects of the non-equilibrium of ionization (NEI) on the detection of hot plasma in coronal loops. Time-dependent loop hydrodynamic simulations are specifically devoted to this task, including saturated thermal conduction, and coupled to the detailed solution of the equations of ionization rate for several abundant elements. In our simulations, initially cool and rarified magnetic flux tubes are heated to 10 MK by nanoflares deposited either at the footpoints or at the loop apex. We test for different pulse durations, and find that, due to NEI effects, the loop plasma may never be detected at temperatures above ~5 MK for heat pulses shorter than about 1 min. We discuss some implications in the framework of multi-stranded nanoflare-heated coronal loops.Comment: 22 pages, 7 figures, accepted for publicatio

Fast Time Structure During Transient Microwave Brightenings: Evidence for Nonthermal Processes

Transient microwave brightenings (TMBs) are small-scale energy releases from the periphery of sunspot umbrae, with a flux density two orders of magnitude smaller than that from a typical flare. Gopalswamy et al (1994) first reported the detection of the TMBs and it was pointed out that the radio emission implied a region of very high magnetic field so that the emission mechanism has to be gyroresonance or nonthermal gyrosynchrotron, but not free-free emission. It was not possible to decide between gyroresonance and gyrosynchrotron processes because of the low time resolution (30 s) used in the data analysis. We have since performed a detailed analysis of the Very Large Array data with full time resolution (3.3 s) at two wavelengths (2 and 3.6 cm) and we can now adequately address the question of the emission mechanism of the TMBs. We find that nonthermal processes indeed take place during the TMBs. We present evidence for nonthermal emission in the form of temporal and spatial structure of the TMBs. The fast time structure cannot be explained by a thermodynamic cooling time and therefore requires a nonthermal process. Using the physical parameters obtained from X-ray and radio observations, we determine the magnetic field parameters of the loop and estimate the energy released during the TMBs. The impulsive components of TMBs imply an energy release rate of 1.3 x 10^22 erg/s so that the thermal energy content of the TMBs could be less than 10^24 erg.Comment: 15 pages (Latex), 4 figures (eps). ApJ Letters in press (1997

The Value Stream Hierarchical Model: A Practical Tool to Apply the Lean Thinking Concepts at All the Firms’ Levels

The increasing competition in the global markets is pushing many manufacturers to start the lean transformation with the final goal of being a Lean Enterprise, which applies the Lean thinking concepts at all its levels, from production to management. The biggest problem in this transition is to have a tool that consistently measures the undergoing evolution in the value stream selected, regardless of its extent, in order to take the subsequent actions needed. The main objective of this paper is to provide such a tool, the Value Stream Hierarchical Model (VSH Model), which could fit with every kind of manufacturing enterprise taking into account also the recent shift to industry 4.0 and the related new technologies available. In addition, another purpose of the model is to provide a scalable point of view that allows to “zoom in” on the company entity, based on the desired level of detail and the related information required. The VSH Model has born as a mix of the architectures existent in literature (ARIS, CIMOSA, PERA), which describe the enterprise from different point of views and levels, and the Lean Thinking concepts, starting from the Lean production tools and variables, passing through the Lean Accounting variables and ending with the Lean Management KPIs. The VSH model has already been applied to practical cases, consisting of a group of companies, as part of the industrial research carried out in Italy by the Politecnico di Torino

EVIDENCE OF WEAK CHAOS WITHIN PLUG-SLUG TRANSITION IN HORIZONTAL TWO PHASE FLOW

Intermittent behaviour has been observed in gas-liquid flows in a horizontal pipe and a weak sign of deterministic chaos has been diagnosed within a transition from plug to slug flow. The analysis has been performed on the basis of an algorithm which exploits the concept of short-term predictability of chaotic motions. The method is completely non-parametric and works whatever the distribution function of the data points may be. The weak sign of chaos is in contrast with the Lorenz-type systems (strong chaos) and supports the idea of Kolmogorov about irregular motion in hydrodynamical systems

TDP-43 and FUS mislocalization in VCP mutant motor neurons is reversed by pharmacological inhibition of the VCP D2 ATPase domain

RNA binding proteins have been shown to play a key role in the pathogenesis of amyotrophic lateral sclerosis (ALS). Mutations in valosin-containing protein (VCP/p97) cause ALS and exhibit the hallmark nuclear-to-cytoplasmic mislocalization of RNA binding proteins (RBPs). However, the mechanism by which mutations in VCP lead to this mislocalization of RBPs remains incompletely resolved. To address this, we used human-induced pluripotent stem cell-derived motor neurons carrying VCP mutations. We first demonstrate reduced nuclear-to-cytoplasmic ratios of transactive response DNA-binding protein 43 (TDP-43), fused in sarcoma/translocated in liposarcoma (FUS) and splicing factor proline and glutamine rich (SFPQ) in VCP mutant motor neurons. Upon closer analysis, we also find these RBPs are mislocalized to motor neuron neurites themselves. To address the hypothesis that altered function of the D2 ATPase domain of VCP causes RBP mislocalization, we used pharmacological inhibition of this domain in control motor neurons and found this does not recapitulate RBP mislocalization phenotypes. However, D2 domain inhibition in VCP mutant motor neurons was able to robustly reverse mislocalization of both TDP-43 and FUS, in addition to partially relocalizing SFPQ from the neurites. Together these results argue for a gain-of-function of D2 ATPase in VCP mutant human motor neurons driving the mislocalization of TDP-43 and FUS. Our data raise the intriguing possibility of harnessing VCP D2 ATPase inhibitors in the treatment of VCP-related ALS