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Disentangling the response of tropical convective updrafts to enhanced aerosol concentrations has been challenging. Leading theories for explaining the influence of aerosol concentrations on tropical convection are based on the dynamical response of convection to changes in cloud microphysics, neglecting possible changes in the environment. In recent years, global convection‐permitting models (GCPM) have been developed to circumvent problems arising from imposing artificial scale separation on physical processes associated with deep convection. Here, we use a global model in the convective gray zone that partially simulates deep convection to investigate how enhanced concentrations of aerosols that act as cloud condensate nuclei (CCN) impact tropical convection features by modulating the convection‐circulation interaction. Results from a pair of idealized non‐rotating radiative‐convective equilibrium simulations show that the enhanced CCN concentration leads to weaker large‐scale circulation, the closeness of deep convective systems to the moist cluster edges, and more mid‐level cloud water at an equilibrium state in which convective self‐aggregation occurred. Correspondingly, the enhanced CCN concentration modulates how the physical processes that support or oppose convective aggregation maintain the aggregated state at equilibrium. Overall, the enhanced CCN concentration facilitates the development of deep convection in a drier environment but reduces mean precipitation. Our results emphasize the importance of allowing atmospheric phenomena to evolve continuously across spatial and temporal scales in simulations when investigating the response of tropical convection to changes in cloud microphysics.

 

This article introduces an analytic formula for entraining convective available potential energy (ECAPE) with an entrainment rate that is determined directly from an environmental sounding, rather than prescribed by the formula user. Entrainment is connected to the background environment using an eddy diffusivity approximation for lateral mixing, updraft geometry assumptions, and mass continuity. These approximations result in a direct correspondence between the storm-relative flow and the updraft radius and an inverse scaling between the updraft radius squared and entrainment rate. The aforementioned concepts, combined with the assumption of adiabatic conservation of moist static energy, yield an explicit analytic equation for ECAPE that depends entirely on state variables in an atmospheric profile and a few constant parameters with values that are established in past literature. Using a simplified Bernoulli-like equation, the ECAPE formula is modified to account for updraft enhancement via kinetic energy extracted from the cloud’s background environment. CAPE and ECAPE can be viewed as predictors of the maximum vertical velocityw_maxin an updraft. Hence, these formulas are evaluated usingw_maxfrom past numerical modeling studies. Both of the new formulas improve predictions ofw_maxsubstantially over commonly used diagnostic parameters, including undiluted CAPE and ECAPE with a constant prescribed entrainment rate. The formula that incorporates environmental kinetic energy contribution to the updraft correctly predicts instances of exceedance ofbyw_max, and provides a conceptual explanation for why such exceedance is rare among past simulations. These formulas are potentially useful in nowcasting and forecasting thunderstorms and as thunderstorm proxies in climate change studies.

Substantial mixing occurs between the upward-moving air currents in thunderstorms (updrafts) and the surrounding comparatively dry environmental air, through a process called entrainment. Entrainment controls thunderstorm intensity via its diluting effect on the buoyancy of air within updrafts. A challenge to representing entrainment in forecasting and predictions of the intensity of updrafts in future climates is to determine how much entrainment will occur in a given thunderstorm environment without a computationally expensive high-resolution simulation. To address this gap, this article derives a new formula that computes entrainment from the properties of a single environmental profile. This formula is shown to predict updraft vertical velocity more accurately than past diagnostics, and can be used in forecasting and climate prediction to improve predictions of thunderstorm behavior and impacts.

 

Are the results of aerosol invigoration studies that neglect entrainment valid for diluted deep convective clouds? We address this question by applying an entraining parcel model to soundings from tropical and midlatitude convective environments, wherein pollution is assumed to increase parcel condensate retention. Invigoration of 5%–10% and <2% is possible in undiluted tropical and midlatitude parcels respectively when freezing is rapid. This occurs because the positive buoyancy contribution from freezing is larger than the negative buoyancy contribution from condensate loading, leading to positive net condensate contribution to buoyancy. However, aerosol‐induced weakening is more likely when realistic entrainment rates occur because water losses from entrainment more substantially reduce the latent heating relative to the loading contribution. This leads to larger net negative buoyancy contribution from condensates in polluted than in clean entraining parcels. Our results demonstrate that accounting for entrainment is critical in conceptual models of aerosol indirect effects in deep convection.

 

Haptic interfaces can be used to add sensations of touch to virtual and augmented reality experiences. Soft, flexible devices that deliver spatiotemporal patterns of touch across the body, potentially with full-body coverage, are of particular interest for a range of applications in medicine, sports and gaming. Here we report a wireless haptic interface of this type, with the ability to display vibro-tactile patterns across large areas of the skin in single units or through a wirelessly coordinated collection of them. The lightweight and flexible designs of these systems incorporate arrays of vibro-haptic actuators at a density of 0.73 actuators per square centimetre, which exceeds the two-point discrimination threshold for mechanical sensation on the skin across nearly all the regions of the body except the hands and face. A range of vibrant sensations and information content can be passed to mechanoreceptors in the skin via time-dependent patterns and amplitudes of actuation controlled through the pressure-sensitive touchscreens of smart devices, in real-time with negligible latency. We show that this technology can be used to convey navigation instructions, to translate musical tracks into tactile patterns and to support sensory replacement feedback for the control of robotic prosthetics. 

Unalloyed nickel aluminide has important applications but lacks ductility at room temperature. In this study, iron-added nickel aluminide alloys exhibit plasticity enhancement. The nickel aluminide alloys are prepared with different iron contents (0, 0.25, and 1 at%) to study their plasticity. The indentation-induced deformed areas are mapped by the synchrotron X-ray diffraction to compare their plastic zones. A complimentary tight binding calculation and generalized embedded atom method demonstrate how the Fe-addition enhances the plasticity of the iron-added nickel aluminide alloys. 

Cowpea (Vigna unguiculata) cultivar B301 is resistant to races SG4 and SG3 of the root parasitic weedStriga gesnerioides, developing a hypersensitive response (HR) at the site of parasite attachment. By contrast, race SG4z overcomes B301 resistance and successfully parasitises the plant.

Comparative transcriptomics andin silicoanalysis identified a small secreted effector protein dubbed Suppressor of Host Resistance 4z (SHR4z) in the SG4z haustorium that upon transfer to the host roots causes a loss of host immunity (i.e. decreased HR and increased parasite growth). SHR4z has significant homology to the short leucine‐rich repeat (LRR) domain of SOMATIC EMBRYOGENESIS RECEPTOR‐LIKE KINASE (SERK) family proteins and functions by binding to VuPOB1, a host BTB‐BACK domain‐containing ubiquitin E3 ligase homologue, leading to its rapid turnover.

VuPOB1 is shown to be a positive regulator of HR since silencing of VuPOB1 expression in transgenic B301 roots lowers the frequency of HR and increases the levels of successful SG4 parasitism and overexpression decreases parasitism by SG4z.

These findings provide new insights into how parasitic weeds overcome host defences and could potentially contribute to the development of novel strategies for controllingStrigaand other parasitic weeds thereby enhancing crop productivity and food security globally.

 

The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro–B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro– to pre–B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1’s critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.