Ubiquitous Mode Research Articles

Tuning Protein Dynamics to Sense Rapid Endoplasmic‐Reticulum Calcium Dynamics

AbstractMulti‐scale calcium (Ca2+) dynamics, exhibiting wide‐ranging temporal kinetics, constitutes a ubiquitous mode of signal transduction. We report a novel endoplasmic‐reticulum (ER)‐targeted Ca2+ indicator, R‐CatchER, which showed superior kinetics in vitro (koff≥2×103 s−1, kon≥7×106 M−1 s−1) and in multiple cell types. R‐CatchER captured spatiotemporal ER Ca2+ dynamics in neurons and hotspots at dendritic branchpoints, enabled the first report of ER Ca2+ oscillations mediated by calcium sensing receptors (CaSRs), and revealed ER Ca2+‐based functional cooperativity of CaSR. We elucidate the mechanism of R‐CatchER and propose a principle to rationally design genetically encoded Ca2+ indicators with a single Ca2+‐binding site and fast kinetics by tuning rapid fluorescent‐protein dynamics and the electrostatic potential around the chromophore. The design principle is supported by the development of G‐CatchER2, an upgrade of our previous (G‐)CatchER with improved dynamic range. Our work may facilitate protein design, visualizing Ca2+ dynamics, and drug discovery.

Characterising optical array particle imaging probes: implications for small-ice-crystal observations

Abstract. The cloud particle concentration, size, and shape data from optical array probes (OAPs) are routinely used to parameterise cloud properties and constrain remote sensing retrievals. This paper characterises the optical response of OAPs using a combination of modelling, laboratory, and field experiments. Significant uncertainties are found to exist with such probes for ice crystal measurements. We describe and test two independent methods to constrain a probe's sample volume that remove the most severely mis-sized particles: (1) greyscale image analysis and (2) co-location using stereoscopic imaging. These methods are tested using field measurements from three research flights in cirrus. For these cases, the new methodologies significantly improve agreement with a holographic imaging probe compared to conventional data-processing protocols, either removing or significantly reducing the concentration of small ice crystals (< 200 µm) in certain conditions. This work suggests that the observational evidence for a ubiquitous mode of small ice particles in ice clouds is likely due to a systematic instrument bias. Size distribution parameterisations based on OAP measurements need to be revisited using these improved methodologies.

The abrupt transition from face-to-face to online treatment for eating disorders: a pilot examination of patients\u2019 perspectives during the COVID-19 lockdown

BackgroundStudies investigating patients’ perspectives towards an abrupt transition from face-to-face to online treatment in eating disorders (EDs) are scarce. The current study aimed to (1) conduct a preliminary assessment of patients’ perspectives regarding this transition, and (2) explore potential demographic, clinical, and treatment-related factors associated with these perspectives.MethodsSixty-three patients with EDs whose treatment was moved to an online format, were surveyed during the COVID-19 lockdown (April–May 2020). A 6-item measure was developed to examine their perspectives toward this transition. Exploratory factor analyses (EFAs) were conducted to confirm the rational-theoretical structure of the measure (Eigenvalue = 3.745, explaining 62.4% of variance). The Cronbach’s alpha value was excellent (α = 0.878). Validated questionnaires were used to measure ED symptoms, general psychopathology, therapeutic alliance, and pandemic anxiety, and their associations with our transition-focused scale and telemedicine satisfaction were examined.ResultsMixed views were found regarding the transition, with the majority (68%) stating that they would not choose to continue online therapy given the option. Longer duration of treatment (r = 0.291, p = 0.022), stronger therapeutic alliance (r = 0.293, p = 0.028), and higher COVID-19 anxiety (r = 0.276, p = 0.029) were linked with more positive views towards the transition.ConclusionsAnalyses suggest that patients’ perspectives towards the transition can be measured using a Likert-type 6-item scale. Findings highlight the various responses to online treatment and indicate a need to identify patients who may face difficulties in the transition to this newly ubiquitous treatment mode. Clinicians should be cognizant of these potential difficulties and consider appropriate modes of treatment in the ongoing pandemic situation.

The design and evaluation of a multimodal ubiquitous learning application for EFL writers

ABSTRACT This study presents the design of a multimodal ubiquitous learning application (MULA) with different augmenting effects for enhancing English as a Foreign Language (EFL) academic writing instruction. In a pilot project, 17 undergraduates engaged in ubiquitous learning and writing at a green building and provided survey responses and interview feedback about their ubiquitous writing experience. The survey results were categorized into perceptions about (a) the ubiquitous learning mode, (b) effective writing facilitation, (c) motivation, self-efficacy, and attitude, (d) self-regulation, and (e) system usability. Interview results further illustrated how using MULA led to positive and negative experiences during ubiquitous writing. A final synthesis on the findings led to the identification of seven affordances that made MULA a potential tool for enhancing writing instruction in EFL settings. The seven affordances were considered effective design elements for multimodal context-aware ubiquitous learning that served the purpose of enriching English academic writing instruction. Implications about creating multimodal ubiquitous learning applications in higher education are also provided.

Multicellular and unicellular responses of microbial biofilms to stress.

Biofilms are a ubiquitous mode of microbial life and display an increased tolerance to different stresses. Inside biofilms, cells may experience both externally applied stresses and internal stresses that emerge as a result of growth in spatially structured communities. In this review, we discuss the spatial scales of different stresses in the context of biofilms, and if cells in biofilms respond to these stresses as a collection of individual cells, or if there are multicellular properties associated with the response. Understanding the organizational level of stress responses in microbial communities can help to clarify multicellular functions of biofilms.

New histological information on Holoptychius Agassiz, 1839 (Sarcopterygii, Porolepiformes) provides insights into the palaeoecological implications and evolution of the basal plate of the scales of osteichthyans

ABSTRACT The porolepiform Holoptychius Agassiz, 1839 from the Upper Devonian is one of the most widely found vertebrates in the Palaeozoic fossil record. Holoptychius is considered to display a more ubiquitous mode of life and a greater potential of dispersion than any other sarcopterygian taxon, consistent with its cosmopolitan distribution and profuse fossil record, mainly represented by scales. Previous studies on the squamation of Holoptychius have discussed the variable ornamentation of the superficial layer; however, the basal plate has been less explored. Here we furnish new histological data on the scales of Holoptychius, focusing on the mineralisation rate and organisation of the lamellar bone. Ground sections show that the basal plate is made of a stacking of thick collagenous layers with a plywood-like structure. Collagenous fibres are parallel within layers, with two successive layers orthogonally arranged and with every second layer rotated by an angle of 36º. This condition, known as a double-twisted plywood-like organisation, is similar to that of other sarcopterygians like Eusthenopteron and extant coelacanths and dipnoans. The new palaeohistological data provide insights into the morphofunctional, palaeoecological and phylogenetical implications of the microstructural characteristics of the scales, adding to our knowledge of the histological diversity of osteichthyans.

The Political Effects of Policy Drift: Policy Stalemate and American Political Development

In recent years, scholars have made major progress in understanding the dynamics of “policy drift”—the transformation of a policy's outcomes due to the failure to update its rules or structures to reflect changing circumstances. Drift is a ubiquitous mode of policy change in America's gridlock-prone polity, and its causes are now well understood. Yet surprisingly little attention has been paid to the political consequences of drift—to the ways in which drift, like the adoption of new policies, may generate its own feedback effects. In this article, we seek to fill this gap. We first outline a set of theoretical expectations about how drift should affect downstream politics. We then examine these dynamics in the context of four policy domains: labor law, health care, welfare, and disability insurance. In each, drift is revealed to be both mobilizing and constraining: While it increases demands for policy innovation, group adaptation, and new group formation, it also delimits the range of possible paths forward. These reactions to drift, in turn, generate new problems, cleavages, and interest alignments that alter subsequent political trajectories. Whether formal policy revision or further stalemate results, these processes reveal key mechanisms through which American politics and policy develop.

Numerical study of ubiquitous modes in tokamak plasmas in the presence of impurities

As an important branch of trapped electron modes (TEMs), the ubiquitous mode (UM) is a favored subject for the investigation of anomalous energy losses in magnetic fusion plasmas. In this paper, the numerical study of UMs was carried out in tokamak plasmas in the presence of impurities. The physical model and the gyrokinetic equations for TEM (and UM) instability is introduced, including the impurity effect. The numerical results show that impurity species impose significant impacts on the UM instability in many ways, one of which is that impurity effect on UMs is generally stabilizing, and on the whole the stabilizing effect is most pronounced for the case of −0.8 ≲ Lez < 0 ( with ). As the impurity charge concentration increases, or for the heavier or lower-ionized impurity ions, the UM instability is weaker. Compared to the ion and electron temperature gradient effects, impurity temperature gradient (expressed by ) has only a minor effect, while the ratio of electron to impurity temperature has a relatively larger effect on UMs, embodied in the mode linear growth rates and instability windows. The investigation of wavenumber threshold for UM showed that the mode was a fluid-like instability when and the presence of impurity resulted in the modification of the UM instability window. By surveying the parametric dependences of UMs in the presence of impurities, it is revealed that comparatively, the stabilizing effects of impurity is more pronounced in the regime of larger wavenumber, while the weakening effects of (i) decreasing the fraction of trapped electrons, (ii) increasing the magnetic shear, or (iii) decreasing the electron density gradient on UM instability are relatively more pronounced in the regime of smaller wavenumber. It also indicates that the stabilizing effect of impurity on UMs is owing to the non-resonant mechanism of the UM.

A decohesion pathway for hydrogen embrittlement in nickel: Mechanism and quantitative prediction

Hydrogen embrittlement (HE) is a ubiquitous and catastrophic mode of fracture in metals. Here, embrittlement is considered as an intrinsic ductile-brittle transition at the crack tip, where H at the crack tip can reduce the stress intensity KIc for cleavage below the value KIe required for ductile dislocation emission and blunting. Specifically, cleavage fracture along (111) planes in Ni occurs due to the formation of just 3 planar layers of H interstitial occupation at a sharp crack tip. During the cleavage process, the sub-surface H in the upper and lower layers can rapidly diffuse to the fracture surface, lowering the net fracture free energy to KIc < KIe and enabling brittle fracture. Details of the process are demonstrated using both first-principles density functional theory and a new interatomic potential for Ni-H. Thermodynamic and kinetic models show that the 3 layers of H can form at the crack tip in equilibrium at room temperature with bulk H concentrations and loading rates where H embrittlement in Ni is observed. The kinetic model also predicts the slow crack growth rate in agreement with experiments. The energetics of the mechanism is then shown to apply to cleavage along grain boundaries. All together, these results show that a version of “Hydrogen enhanced decohesion” is the operative embrittlement mechanism in Ni.

Characteristic Fatigue Life Research on the Centrifugal Impeller

The researched work quite essentially deals with the resoluteness of the safety and structural integrity of the centrifugal impeller in withstanding the forces impacted on the targeted materials Ti-6Al-4V and Au2gn. In order to counteract the effects prevalent as a result of profound instabilities such as surging, stalling and choking, the materials were subjected to an intense comparative study, undertaken with respect to primary parameters such as good strength yield, in addition to dispensing a rotational speed of 20000 rpm. The preliminary solid modeling was executed using CATIAV5. Structural Analysis is carried out using ANSYS software in order to establish their strengths together with the location of maximum stress and strain. 2D FEM simulation was done on the impeller. Furthermore the number of cycles to failure was computed using the best amongst the known strain – based life estimation methods. From the modal analysis the ubiquitous critical mode shape along with the frequency at which the maximum relative displacement occurs were obtained. Finally, Ti-6Al-4V was affirmed to be better than Au2gn.

How Else Would You Take a Photo? #SelfieAmbivalence

Popular discourse describing selfies as the “narcissistic”2 practice of teenagers or a tool of personal empowerment, minimize the structural constraints under which selfies operate as a ubiquitous mode of sociality. Based on focus group discussions in two Canadian cities, we explore how young adults describe their selfie experiences and explore three discursive tensions expressed in the transcripts. First, how questions of “control” were taken up; second, how “visibility” was understood as fragile, and animated by an anxiety of invisibility; third, the nature of “fun” that selfies generate. We conclude by exploring some of the epistemological shifts that these practices indicate.

Anomalous attenuation of plasmons in strange metals and holography

The plasmon is a ubiquitous collective mode in charged liquids. Due to the long-range Coulomb interaction, the massless zero sound mode of the neutral system acquires a finite plasmon frequency in the long-wavelength limit. In the zero-temperature state of conventional metals -- the Fermi liquid -- the plasmon lives infinitely long at long wavelength when the system is (effectively) translationally invariant. In contrast, we will show that in strongly entangled strange metals the protection of zero sound fails at finite frequency and plasmons are always short lived regardless of their wavelength. Computing the explicit plasmon response in holographic strange metals as an example, we show that decay into the quantum critical continuum replaces Landau damping and this happens for any wavelength.

Hardcore Style, Queer Heteroeroticism, and After Dark

During the early to mid-1970s, when feature-length hardcore films became a popular cultural phenomenon in the United States, hardcore came to designate more than just a genre or an industry—it became a ubiquitous mode of performance, an ethos, and a style. This article explores how hardcore as a style was taken up by the popular gay-marketed entertainment magazine After Dark. Through a close descriptive analysis of three photo spreads from 1975–76, it illuminates how female, gay male, and otherwise non-straight-identifying performers participated in a hardcore stylistic that, paradoxically, worked to shape queer elaborations of heteroeroticism. Within these vital images of singers, dancers, models, and performance artists, created at the height of hardcore's newfound cultural influence, performances of female-male coupling and group-centered socio-sexual activity both worked with and moved to dissolve normative heterosexist configurations of sex and gender.

Focusing of Shear Shock Waves

Focusing is an ubiquitous mode of transforming waves---even within the human body, as it turns out. Recently, high-frame-rate ultrasound has enabled the observation of shear shock waves in soft solids, such as the brain. The present study uses that technique to further show that shear waves emitted by a cylindrical source into tissue-mimicking gelatin can be focused, and that they form a shock at the focus. This could explain why traumatic brain injuries, such as diffuse axonal injury, occur deep inside the organ, rather than near the skull.

A Candid Advantage? The Social Benefits of Candid Photos

Photos are a ubiquitous mode of social communication. Analysis of thousands of online profiles finds that people overwhelmingly post posed photos of themselves. But might candids actually lead observers to react more favorably? Five studies test this possibility. Compared to posed photos, candids made observers feel more connected to the poster, feel more interested in getting to know or date them, and like them more. This was driven by candids making people seem more genuine, which made others react more favorably. Furthermore, consistent with the hypothesized role of genuineness, the benefits of candids were diminished when observers learned that the poster realized their photo was being taken. These finding highlight the role of authenticity in person perception and a potential disconnect between photo posters and viewers. Although posters seem to post mostly posed photos, observers may prefer candids because they provide a more authentic sense of who the poster really is.

The Power of Satire

The Power of Satire

Collisionless microinstabilities in stellarators. Part 4. The ion-driven trapped-electron mode

Optimised stellarators and other magnetic-confinement devices having the property that the average magnetic curvature is favourable for all particle orbits are called maximum-$J$ devices. They have recently been shown to be immune to trapped-particle instabilities driven by the density gradient. Gyrokinetic simulations reveal, however, that another instability can arise, which is also associated with particle trapping but causes less transport than typical trapped-electron modes. The nature of this instability is clarified here. It is shown to be similar to the ‘ubiquitous mode’ in tokamaks and is driven by ion free energy, but requires trapped electrons to exist.

Transient bifurcation condition of partially saturated porous media at finite strain

SummaryBifurcation of unsaturated soils into a localized shear band is a ubiquitous failure mode of partially saturated soils. The density and degree of saturation have major impacts on the inception of localized deformations in unsaturated soils. Unsaturated fluid flow may dramatically change the density and degree of fluid saturation of unsaturated soils. Therefore, the unsaturated fluid flow is a potential trigger for shear banding in such materials. In this paper, we derive a simplified bifurcation condition of localized deformation in unsaturated soils under the local transient condition at finite strain. This transient bifurcation condition is implemented into a nonlinear finite element code to study the inception of localized deformation in unsaturated soil specimens. Numerical simulations are conducted to study the impact of soil fabrics of density, a ‘bonding’ variable, and intrinsic permeability on the inception of localized failures via the transient bifurcation criterion. Mesh sensitivity analysis is performed to demonstrate the viscosity effect of unsaturated fluid flow on the localized deformation. Numerical simulations demonstrate that the transient bifurcation condition can detect the localized deformation triggered by the internal unsaturated fluid flow process in unsaturated soils. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Widespread transcriptional gene inactivation initiated by a repair intermediate of 8-oxoguanine.

DNA damage can significantly modulate expression of the affected genes either by direct structural interference with transcription components or as a collateral outcome of cellular repair attempts. Thus, DNA glycosylases of the base excision repair (BER) pathway have been implicated in negative transcriptional response to several spontaneously generated DNA base modifications, including a common oxidative DNA base modification 8-oxoguanine (8-oxoG). Here, we report that single 8-oxoG situated in the non-transcribed DNA strand of a reporter gene has a pronounced negative effect on transcription, driven by promoters of various strength and with different structural properties, including viral, human, and artificial promoters. We further show that the magnitude of the negative effect on the gene expression correlates with excision of the modified base by OGG1 in all promoter constructs tested. Moreover, by using expression vectors with nuclease resistant backbone modifications, we demonstrate that OGG1 does not catalyse DNA strand cleavage in vivo. Rather, cleavage of the phosphate bond 5′ to 8-oxodG (catalysed by APE1) is essential and universally required for the onset of transcriptional silencing, regardless of the promoter structure. Hence, induction of transcriptional silencing emerges as a ubiquitous mode of biological response to 8-oxoG in DNA.

Validation of a Novel Delay Discounting of Text Messaging Questionnaire

Using cellular phones for text messaging has become a ubiquitous mode of communication in today’s American culture. Text messaging has become a primary source of relationship development and maintenance for many Americans, especially youth. Researchers have begun classifying excessive reliance on text messaging as an addictive behavior, which may lead to risky activities such as texting while driving. This study interprets texting dependence within a behavioral economics framework of addictive behavior and proposes a novel Delay Discounting of Texting Questionnaire (DDTQ). The DDTQ involves a hypothetical scenario wherein the respondent chooses between paying for an immediate text now and waiting to receive a free text message in the future. We validated the DDTQ using a relatively diverse crowdsourced sample from Amazon Mechanical Turk. The DDTQ demonstrated expected degrees of systematic discounting and yielded higher rates of delay discounting with reward values in a within-subjects evaluation of the magnitude effect. Finally, the DDTQ successfully discriminated different profiles of possible text-messaging dependence. Collectively, these findings suggest the DDTQ is a viable task for use in studying the behavioral economics of possible text-messaging dependence.