The search for dark matter annihilation in galaxy clusters at VERITAS

Recent data and cosmological models point to a significant fraction of the Universe being comprised of Cold Dark Matter (DM), though little is known about it directly as it does not interact electromagnetically. The most likely explanation for DM is a Weakly Interacting Massive Particle (WIMP) having a mass as low as ∼10 GeV to as high as ∼10 TeV. WIMPs are believed to be their own antiparticles and self-annihilate into a variety of lighter particles including γ-rays. Many direct detection, indirect detection, and direct production schemes have been proposed to search for the elusive WIMP. Galaxy clusters, consisting of hundreds to thousands of galaxies, are the largest collections of matter in the Universe held together by gravity. As such, galaxy clusters also contain the highest concentrations of DM found anywhere. This thesis presents results on the VERITAS observations of 12 galaxy clusters selected from archival data. We seek to detect the γ-rays originating from the DM interactions within galaxy clusters. We calculate astrophysical J-factors for each of the galaxy clusters six of which had no prior J-factors with the DM simulations package CLUMPY. Since a DM detection is not made, the limit to the thermally-averaged DM annihilation velocity-weighted cross-section is then computed from the γ-ray flux upper limit. We employ a stacking method to combine the limits of the 12 galaxy clusters. The limits from the stacking method are found to be less constraining than some individual galaxy clusters due to the wide range of limits considered. We conclude that a larger number of galaxy clusters in the stacking method will yield more competitive limits to other DM searches

Gene-environment interaction influences attachment-like style in mice

Attachment styles are established soon after birth and form the basis for a healthy psychological life during adulthood. Here, we investigated whether genetic background (i.e. isogenic strains: C57BL/6N and BALB/c) and parent-of-origin (i.e. reciprocal hybrids) epigenetic effects influence attachment-like styles in mice. We discovered that a specific genetic and epigenetic assortment exerts a role on the development of a secure or insecure attachment-like style. In particular, when biological mothers raise their pups, the attachment-like style is mainly secure, independently of the genetic background. However, when foster mothers raise pups, the attachment-like style can be either secure or insecure, depending on the particular genetic background, and this effect is paternally transmitted. Finally, we observed that secure attachment-like in mice leads to greater sociability during adulthood, while insecure attachment-like leads to reduced sociability. Our study sheds light on gene-environment interactions that shape the attachment-like style early in development and pave the way for a healthy psychological life

ANALYSIS OF THE FACTORS AFFECTING 3D MODELS RESOLUTION – APPLICATION TO THE RECORDING OF VAULTS IN SANGALLO'S HOUSE

The paper will present the extraction of information from a laser scanning survey aimed to support historical studies on the Sangallo's house in Florence. In order to verify some study's hypothesis related to the building history and constructive techniques, high resolution models were needed. The meaning of "resolution" applied to 3D scanning will be briefly discussed stressing the difference between resolution and accuracy. Starting from the analysis of technical specifications of the used instruments, the expected performance of the model is described. The results obtained from acquired data are shown and the paper will conclude proposing some answers to the historian's questions

Mobility and Congestion in Dynamical Multilayer Networks with Finite Storage Capacity

Multilayer networks describe well many real interconnected communication and transportation systems, ranging from computer networks to multimodal mobility infrastructures. Here, we introduce a model in which the nodes have a limited capacity of storing and processing the agents moving over a multilayer network, and their congestions trigger temporary faults which, in turn, dynamically affect the routing of agents seeking for uncongested paths. The study of the network performance under different layer velocities and node maximum capacities, reveals the existence of delicate trade-offs between the number of served agents and their time to travel to destination. We provide analytical estimates of the optimal buffer size at which the travel time is minimum and of its dependence on the velocity and number of links at the different layers. Phenomena reminiscent of the Slower Is Faster (SIF) effect and of the Braess' paradox are observed in our dynamical multilayer set-up.Comment: 5 pages, 3 figure

Photogrammetry and 3D printing for marble statues replicas: Critical issues and assessment

A project for realizing replicas of a couple of marble statues starting from reality-based 3D models is being presented in this paper. On the crowning element of the baptistry, consecrated to San Giovanni in Corte in Pistoia (Italy), there were originally a couple of marble statues that, in the 1980s, were removed to preserve them better and to avoid security issues. Recently, the Superintendence started a project aimed to reproduce both statues with additive manufacturing techniques. High-resolution 3D models are required for supporting the replica process. This project takes advantage of the structure from motion (SfM) technique to produce reality-based models and fused deposition modeling (FDM) to 3D print the replicas. This paper presents an overview of the potential of additive manufacturing systems in the field of cultural heritage conservation and describes all the phases of the project, up to the evaluation of the correspondence between the original and the copy

Optimization of graphene-based materials outperforming host epoxy matrices

The degree of graphite exfoliation and edge-carboxylated layers can be controlled and balanced to design lightweight materials characterized by both low electrical percolation thresholds (EPT) and improved mechanical properties. So far, this challenging task has been undoubtedly very hard to achieve. The results presented in this paper highlight the effect of exfoliation degree and the role of edge-carboxylated graphite layers to give self-assembled structures embedded in the polymeric matrix. Graphene layers inside the matrix may serve as building blocks of complex systems that could outperform the host matrix. Improvements in electrical percolation and mechanical performance have been obtained by a synergic effect due to finely balancing the degree of exfoliation and the chemistry of graphene edges which favors the interfacial interaction between polymer and carbon layers. In particular, for epoxy-based resins including two partially exfoliated graphite samples, differing essentially in the content of carboxylated groups, the percolation threshold reduces from 3 wt% down to 0.3 wt%, as the carboxylated group content increases up to 10 wt%. Edge-carboxylated nanosheets also increase the nanofiller/epoxy matrix interaction, determining a relevant reinforcement in the elastic modulus

A framework for temporal and spatial rockfall early warning using micro-seismic monitoring

Rockfall risk is usually characterized by a high frequency of occurrence, difficulty in prediction (given high velocity, lack of noticeable forerunners, abrupt collapse, and complex mechanism), and a relatively high potential vulnerability, especially against people and communication routes. Considering that larger rockfalls and rockslides are generally anticipated by an increased occurrence of events, in this study, a framework based on microseismic monitoring is introduced for a temporal and spatial rockfall early warning. This approach is realized through the detection, classification, and localization of all the rockfalls recorded during a 6-month-long microseismic monitoring performed in a limestone quarry in central Italy. Then, in order to provide a temporal warning, an observable quantity of accumulated energy, associated to the rockfall rolling and bouncing and function of the number and volume of events in a certain time window, has been defined. This concept is based on the material failure method developed by Fukuzono-Voight. As soon as the first predicted time of failure and relative warning time are declared, all the rockfalls occurred in a previous time window can be located in a topographic map to find the rockfall susceptible area and thus to complement the warning with spatial information. This methodology has been successfully validated in an ex post analysis performed in the aforementioned quarry, where a large rockfall was forecasted with a lead time of 3 min. This framework provides a novel way for rockfall spatiotemporal early warning, and it could be helpful for activating traffic lights and closing mountain roads or other transportation lines using the knowledge of the time and location of a failure. Since this approach is not based on the detection of the triggering events (like for early warnings based on rainfall thresholds), it can be used also for earthquake-induced failures

Three years field trials to assess the effect of kaolin made particles and copper on olive-fruit fly (B.oleae Gmelin) infestations in Sicily

In most countries of Mediterranean Basin, Bactrocera oleae (Gmel), the olive fruit fly, is the key pest insect on olives. In Sicily this pest causes losses of fruits and a poor quality olive oil. Many researchers have recently carried out some field studies which were based on the use of kaolin and copper against the olive-fruit fly. In the last years these products have been effective several times in reducing olive fly infestation. Kaolin had, also, some important effect in reducing heat-stress in fruit crops and olive-trees. The aim of the present study was to assess the effect of kaolin and copper treatment on olive infestations in Sicily and to evaluate chemical and sensory parameters of oils extracted. For this reason, within 2003-2005, the IX Servizio of Assessorato Regionale Agricoltura e Foreste, selected some olive groves where to carry out trials with kaolin and copper and to realize information and divulgation activities

Photo editing: Enhancing social media images to reflect appearance ideals

Many of the images used in traditional forms of mass media have been modified to portray unrealistic and idealised beauty characteristics. Further to this, members of the general public have now begun to digitally enhance their own pictures for social media posts, in order to fulfil these often unattainable standards. Ella Guest explores the impact exposure to idealised images of peers may have on health and wellbein