2,176 research outputs found
A model for the time uncertainty measurements in the Auger surface detector array
The precise determination of the arrival direction of cosmic rays is a
fundamental prerequisite for the search for sources or the study of their
anisotropies on the sky. One of the most important aspects to achieve an
optimal measurement of these directions is to properly take into account the
measurement uncertainties in the estimation procedure. In this article we
present a model for the uncertainties associated with the time measurements in
the Auger surface detector array. We show that this model represents well the
measurement uncertainties and therefore provides the basis for an optimal
determination of the arrival direction. With this model and a description of
the shower front geometry it is possible to estimate, on an event by event
basis, the uncertainty associated with the determination of the arrival
directions of the cosmic rays
Combining high-resolution scanning tunnelling microscopy and first-principles simulations to identify halogen bonding
Scanning tunnelling microscopy (STM) is commonly used to identify on-surface molecular self-assembled structures. However, its limited ability to reveal only the overall shape of molecules and their relative positions is not always enough to fully solve a supramolecular structure. Here, we analyse the assembly of a brominated polycyclic aromatic molecule on Au(111) and demonstrate that standard STM measurements cannot conclusively establish the nature of the intermolecular interactions. By performing high-resolution STM with a CO-functionalised tip, we clearly identify the location of rings and halogen atoms, determining that halogen bonding governs the assemblies. This is supported by density functional theory calculations that predict a stronger interaction energy for halogen rather than hydrogen bonding and by an electron density topology analysis that identifies characteristic features of halogen bonding. A similar approach should be able to solve many complex 2D supramolecular structures, and we predict its increasing use in molecular nanoscience at surfaces
First test of a BAE transducing scheme on a Resonant Gravitational-Wave Antenna
We present the results obtained with a resonant capacitive transducer, suitable for Back Action Evasion (BAE) measurements, coupled for the first time to a
gravitational-wave antenna. This scheme was developed in collaboration with the
Group of the University of Rome La Sapienza. The antenna is a 270 kg aluminum 5056 alloy cylinder, with a resonant frequency of 1805 Hz, operating at 4.2K in the ALTAIR
cryostat, located in Frascati (Italy) at the IFSI-CNR laboratory. The apparatus was able to work continuously for periods as long as days, both in up-conversion and BAE
configurations, with good stability. The behaviour of the system is in reasonable Agreement with a proposed model of a double harmonic oscillator in a BAE readout scheme. The limits on the sensitivity of this set-up are discussed as well as the possible future improvements
Enhanced pre-frontal functional-structural networks to support postural control deficits after traumatic brain injury in a pediatric population
Traumatic brain injury (TBI) affects the structural connectivity, triggering the re-organization of structural-functional circuits in a manner that remains poorly understood.
We focus here on brain networks re-organization in relation to postural control deficits after TBI. We enrolled young participants who had suffered moderate to severeTBI, comparing them to young typically developing control participants. In comparison to control participants, TBI patients (but not controls) recruited prefrontal
regions to interact with two separated networks: 1) a subcortical network including part of the motor network, basal ganglia, cerebellum, hippocampus, amygdala, posterior cingulum and precuneus; and 2) a task-positive network, involving regions of the dorsal attention system together with the dorsolateral and ventrolateral prefrontal regions
Successful private–public funding of paediatric medicines research: lessons from the EU programme to fund research into off-patent medicines
The European Paediatric Regulation mandated the European Commission to fund research on off-patent medicines with demonstrated therapeutic interest for children. Responding to this mandate, five FP7 project calls were launched and 20 projects were granted. This paper aims to detail the funded projects and their preliminary results. Publicly
available sources have been consulted and a descriptive
analysis has been performed. Twenty Research Consortia
including 246 partners in 29 European and non-European
countries were created (involving 129 universities or public funded research organisations, 51 private companies with 40 SMEs, 7 patient associations). The funded projects investigate 24 medicines, covering 10 therapeutic areas in all paediatric age groups. In response to the Paediatric Regulation and to apply for a Paediatric Use Marketing Authorisation, 15 Paediatric Investigation Plans have been granted by the EMAPaediatric Committee, including 71 studies of whom 29 paediatric clinical trials, leading to a total of 7,300 children to be recruited in more than 380 investigational centres.
Conclusion: Notwithstanding the EU contribution for each
study is lower than similar publicly funded projects, and also considering the complexity of paediatric research, these projects are performing high-quality research and are progressing towards the increase of new paediatric medicines on the market. Private–public partnerships have been effectively implemented, providing a good example for future collaborative actions. Since these projects cover a limited number of offpatent drugs and many unmet therapeutic needs in paediatrics remain, it is crucial foreseeing new similar initiatives in forthcoming European funding programmes
Ruptured aortic arch aneurysm: transposition of aortic arch branches after insertion of thoracic endovascular stent with extra-anatomic brain perfusion
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Minimally invasive rehabilitation of a severely atrophic and fully edentulous maxilla using 4-mm-ultrashort implants: A case report with 1-year follow-up
This case report describes an alternative minimally invasive treatment option using 4-mm-long ultrashort implants placed to rehabilitate a severely atrophic edentulous maxilla. The patient, coming from a full removable denture, asked for an implant prosthesis avoiding reconstructive surgeries and expensive procedures. Considering that the mean available bone was about 4.8 mm in height on Cone Beam Computed Tomography (CBCT) scans, 6 implants were placed where bone volumes were sufficient to receive 4-mm-ultrashort implants. Six months after implant placement an implant-supported bar-retained overdenture prosthesis was delivered. The healing process was uneventful and 1 year after loading the result appears clinically and radiographically stable and the patient is fully satisfied. The described approach, despite some prosthetic compromises, within all the limitations of this case report, might be applied in selected cases, reducing rehabilitative times, possible complications and costs. However, longer follow-ups on large number of patients coming from Randomised Controlled clinical Trials (RCTs) are necessary before making more reliable recommendations
Deep shower interpretation of the cosmic ray events observed in excess of the Greisen-Zatsepin-Kuzmin energy
We consider the possibility that the ultra-high-energy cosmic ray flux has a
small component of exotic particles which create showers much deeper in the
atmosphere than ordinary hadronic primaries. It is shown that applying the
conventional AGASA/HiRes/Auger data analysis procedures to such exotic events
results in large systematic biases in the energy spectrum measurement. SubGZK
exotic showers may be mis-reconstructed with much higher energies and mimick
superGZK events. Alternatively, superGZK exotic showers may elude detection by
conventional fluorescence analysis techniques.Comment: 22 pages, 5 figure
Perception of changes in marine benthic habitats: The relevance of taxonomic and ecological memory
Having a reliable ecological reference baseline is pivotal to understanding the current status of benthic assemblages. Ecological awareness of our perception of environmental changes could be better described based on historical data. Otherwise, we meet with the shifting baseline syndrome (SBS). Facing SBS harmful consequences on environmental and cultural heritage, as well as on conservation strategies, requires combining historical data with contemporary biomonitoring. In the present “era of biodiversity”, we advocate for (1) the crucial role of taxonomy as a study of life diversity and (2) the robust, informative value of museum collections as memories of past ecosystem conditions. This scenario requires taxonomist skills to understand community composition and diversity, as well as to determine ecosystem change trends and rates. In this paper, we focus on six Mediterranean benthic habitats to track biological and structural changes that have occurred in the last few decades. We highlight the perception of biological changes when historical records make possible effective comparisons between past reference situations and current data. We conclude that the better we know the past, the more we understand present (and will understand future) ecosystem functioning. Achieving this goal is intrinsically linked to investing in training new taxonomists who are able to assure intergeneration connectivity to transmit cultural and environmental heritage, a key aspect to understanding and managing our changing ecosystems
Leveraging fluorescent emission to unitary yield: dimerization of polycyclic aromatic hydrocarbons
We report on the synthesis and characterization of novel substituted 1,1′‐biperylene‐2,2′‐diols in which the dihedral angle between the two polycyclic aromatic hydrocarbon (PAH) units is tailored from ca. 60° to ca. 90° in the solid state by introduction of cyclo‐etheric straps or sterically hindered groups such as the triisopropylsilyl (TIPS) group. Depending on the type of substitution, we lock the dihedral angle between the perylenyl moieties enabling fine‐tuning of the molecular optoelectronic properties, with the molecules displaying the smallest angles acting as exceptionally strong emitters with unitary quantum yields
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