Communication, coordination, and surveillance in the shadow of repression

Abstract: Communication technology helps protesters organize, but also allows the government to monitor and repress their actions. We study this trade‐off in a model where protesters want to show up at the same time and place, but also want to avoid government forces. If leaders of a movement can send messages observed only by other protesters, they can successfully coordinate on a variety of sites and force the government to spread resources thin, helping the success of the movement. If the government always observes the messages too, protesters can do no better than always going to a “focal site” knowing that the government will send all resources there as well, and thus experience higher levels of repression for the sake of coordinating tactics. Intermediate cases where messages are partially observed generate dynamics where new technologies and media that are relatively known to other protesters and not the government are used until the government can reliably infiltrate them and the protesters move on to a new medium. When some protesters are more informed than others, the model can explain protest tactics observed in recent prominent cases like having smaller “parallel” protests at the same time but different location of the main gathering

The Evolution of Diffuse Radio Sources in Galaxy Clusters

We investigate the evolution and number distribution of radio halos in galaxy clusters. Without re-acceleration or regeneration, the relativistic electrons responsible for the diffuse radio emission will lose their energy via inverse-Compton and synchrotron losses in a rather short time, and radio halos will have lifetimes $\sim$ 0.1 Gyr. Radio halos could last for $\sim$ Gyr if a significant level of re-acceleration is involved. The lifetimes of radio halos would be comparable with the cosmological time if the radio-emitting electrons are mainly the secondary electrons generated by pion decay following proton-proton collisions between cosmic-ray protons and the thermal intra-cluster medium within the galaxy clusters. Adopting both observational and theoretical constraints for the formation of radio halos, we calculate the formation rates and the comoving number density of radio halos in the hierarchical clustering scheme. Comparing with observations, we find that the lifetimes of radio halos are $\sim$ Gyr. Our results indicate that a significant level of re-acceleration is necessary for the observed radio halos and the secondary electrons may not be a dominant origin for radio halos.Comment: 22 pages, 6 figures, ApJ, in press (v2:Corrected typos.

A review of the MSCA ITN ECOSTORE - Novel complex metal hydrides for efficient and compact storage of renewable energy as hydrogen and electricity

Hydrogen as an energy carrier is very versatile in energy storage applications. Developments in novel, sustainable technologies towards a CO2-free society are needed and the exploration of all-solid-state batteries (ASSBs) as well as solid-state hydrogen storage applications based on metal hydrides can provide solutions for such technologies. However, there are still many technical challenges for both hydrogen storage material and ASSBs related to designing low-cost materials with low-environmental impact. The current materials considered for all-solid-state batteries should have high conductivities for Na+, Mg2+ and Ca2+, while Al3+-based compounds are often marginalised due to the lack of suitable electrode and electrolyte materials. In hydrogen storage materials, the sluggish kinetic behaviour of solid-state hydride materials is one of the key constraints that limit their practical uses. Therefore, it is necessary to overcome the kinetic issues of hydride materials before discussing and considering them on the system level. This review summarizes the achievements of the Marie Skłodowska-Curie Actions (MSCA) innovative training network (ITN) ECOSTORE, the aim of which was the investigation of different aspects of (complex) metal hydride materials. Advances in battery and hydrogen storage materials for the efficient and compact storage of renewable energy production are discussed

Diagnostic Signatures of Radio and HXR Emission on Particle Acceleration Processes in the Coma Cluster

We investigate theoretical models for the radio halo and hard X-ray (HXR) excess in the Coma galaxy cluster. Time-independent and time-dependent re-acceleration models for relativistic electrons have been carried out to study the formation of the radio halo and HXR excess. In these models, the relativistic electrons are injected by merger shocks and re-accelerated by ensuing violent turbulence. The effects of different Mach numbers of the merger shocks on the radio and HXR excess emission are also investigated. We adopt 6 $\mu$G as the central magnetic field and reproduce the observed radio spectra via the synchrotron emission. We also obtain a central "plateau" in the radio spectral-index distribution, which have been observed in radio emission distribution. Our models can also produce the observed HXR excess emission via the inverse Compton scattering of the cosmic microwave background photons. We find that only the merger shocks with the Mach numbers around 1.6--2 can produce results in agreement with both the radio and HXR emission in the Coma cluster.Comment: 29 pages, 10 figures, ApJ in pres

Developmental Changes in PON1 Enzyme Activity in Young Children and Effects of PON1 Polymorphisms

BackgroundParaoxonase 1 (PON1) is an enzyme that detoxifies activated organophosphorus pesticides (OPs) and is also involved in oxidative stress pathways.ObjectivesPON1 activity in newborns is lower than in adults, but the ontogeny of PON1 activity is poorly characterized in young children. We examined the effects of age and PON1 genotype on enzyme activity in a birth cohort of Mexican-American children.MethodsWe determined three substrate-specific measures of PON1 activity in 1,143 plasma samples collected longitudinally from 458 children at five time points from birth through 7 years of age, and genotyped PON1 polymorphisms at positions 192 and -108 in these children.ResultsContrary to previous reports that PON1 activities plateau by 2 years of age, we observed an age-dependent increase in all three PON1 measures from birth through 7 years of age (p < 0.0001). The PON1(192) genotype significantly modified the effect of age on paraoxonase (POase) activity (p < 0.0001) such that increases in enzyme activity with age were influenced by the number of R alleles in a dose-dependent manner. Children with the PON1(-108CC192RR) diplotype had significantly higher mean PON1 activities and also experienced steeper increases of POase activity over time compared with children with the PON1(-108TT192QQ) diplotype.ConclusionsLower levels of the PON1 enzyme, which is involved in protection against OPs and oxidative stress, persist in young children past 2 years of age through at least 7 years of age. Future policies addressing pesticide exposure in children should take into account that the window of vulnerability to OPs in young children may last beyond infancy

Mutation screening of the RNF8, UBC13 and MMS2 genes in Northern Finnish breast cancer families

<p>Abstract</p> <p>Background</p> <p>Currently known susceptibility genes such as <it>BRCA1 </it>and <it>BRCA2 </it>explain less than 25% of familial aggregation of breast cancer, which suggests the involvement of additional susceptibility genes. RNF8, UBC13 and MMS2 are involved in the DNA damage response pathway and play important roles in BRCA1-mediated DNA damage recognition. Based on the evidence that several players in the ubiquitin-mediated BRCA1-dependent DDR seem to contribute to breast cancer predisposition, <it>RNF8, UBC13 </it>and <it>MMS2 </it>were considered plausible candidate genes for susceptibility to breast cancer.</p> <p>Methods</p> <p>The entire coding region and splice junctions of <it>RNF8, UBC13 </it>and <it>MMS2 </it>genes were screened for mutations in affected index cases from 123 Northern Finnish breast cancer families by using conformation sensitive gel electrophoresis, high resolution melting (HRM) analysis and direct sequencing.</p> <p>Results</p> <p>Mutation analysis revealed several changes in <it>RNF8 </it>and <it>UBC13</it>, whereas no aberrations were observed in <it>MMS2</it>. None of the found sequence changes appeared to associate with breast cancer susceptibility.</p> <p>Conclusions</p> <p>The present data suggest that mutations in <it>RNF8, UBC13 </it>and <it>MMS2 </it>genes unlikely make any sizeable contribution to breast cancer predisposition in Northern Finland.</p

A Twilight Search for Atiras, Vatiras, and Co-orbital Asteroids: Preliminary Results

Near-Earth objects (NEOs) that orbit the Sun on or within Earth's orbit are tricky to detect for Earth-based observers due to their proximity to the Sun in the sky. These small bodies hold clues to the dynamical history of the inner solar system as well as the physical evolution of planetesimals in extreme environments. Populations in this region include the Atira and Vatira asteroids, as well as Venus and Earth co-orbital asteroids. Here we present a twilight search for these small bodies, conducted using the 1.2 m Oschin Schmidt and the Zwicky Transient Facility (ZTF) camera at Palomar Observatory. The ZTF twilight survey operates at solar elongations down to 35° with a limiting magnitude of r = 19.5. During a total of 40 evening sessions and 62 morning sessions conducted between 2018 November 15 and 2019 June 23, we detected six Atiras, including two new discoveries, 2019 AQ₃ and 2019 LF₆, but no Vatiras or Earth/Venus co-orbital asteroids. NEO population models show that these new discoveries are likely only the tip of the iceberg, with the bulk of the population yet to be found. The population models also suggest that we have only detected 5%–7% of the H < 20 Atira population over the seven month survey. Co-orbital asteroids are smaller in diameter and require deeper surveys. A systematic and efficient survey of the near-Sun region will require deeper searches and/or facilities that can operate at small solar elongations

PON1 and Neurodevelopment in Children from the CHAMACOS Study Exposed to Organophosphate Pesticides in Utero

BackgroundParaoxonase 1 (PON1) detoxifies oxon derivatives of some organophosphate (OP) pesticides, and its genetic polymorphisms influence enzyme activity and quantity. We previously reported that maternal urinary concentrations of dialkyl phosphate (DAP) metabolites, a marker of OP pesticide exposure, were related to poorer mental development and maternally reported symptoms consistent with pervasive developmental disorder (PDD) in 2-year-olds participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study.ObjectiveWe determined whether PON1 genotypes and enzyme measurements were associated with child neurobehavioral development and whether PON1 modified the association of in utero exposure to OPs (as assessed by maternal DAPs) and neurobehavior.MethodsWe measured DAP concentrations in maternal urine during pregnancy, PON1₁₉₂ and PON1₋₁₀₈ genotypes in mothers and children, and arylesterase (ARYase) and paraoxonase (POase) in maternal, cord, and 2-year-olds' blood. We assessed 353 2-year-olds on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) of the Bayley Scales of Infant Development and queried their mothers on the Child Behavior Checklist to obtain a score for PDD.ResultsChildren with the PON1(-108T) allele had poorer MDI scores and somewhat poorer PDI scores. Children were less likely to display PDD when they or their mothers had higher ARYase activity and when their mothers had higher POase activity. The association between DAPs and MDI scores was strongest in children with PON1(-108T) allele, but this and other interactions between DAPs and PON1 polymorphisms or enzymes were not significant.ConclusionPON1 was associated with child neurobehavioral development, but additional research is needed to confirm whether it modifies the relation with in utero OP exposure

Desmoplakin assembly dynamics in four dimensions: multiple phases differentially regulated by intermediate filaments and actin

The intermediate filament (IF)–binding protein desmoplakin (DP) is essential for desmosome function and tissue integrity, but its role in junction assembly is poorly understood. Using time-lapse imaging, we show that cell–cell contact triggers three temporally overlapping phases of DP-GFP dynamics: (1) the de novo appearance of punctate fluorescence at new contact zones after as little as 3 min; (2) the coalescence of DP and the armadillo protein plakophilin 2 into discrete cytoplasmic particles after as little as 15 min; and (3) the cytochalasin-sensitive translocation of cytoplasmic particles to maturing borders, with kinetics ranging from 0.002 to 0.04 μm/s. DP mutants that abrogate or enhance association with IFs exhibit delayed incorporation into junctions, altering particle trajectory or increasing particle pause times, respectively. Our data are consistent with the idea that DP assembles into nascent junctions from both diffusible and particulate pools in a temporally overlapping series of events triggered by cell–cell contact and regulated by actin and DP–IF interactions