Search results for "Relativity"

Ajan ja avaruuden käsitteet ovat sekä filosofiaa että fysiikkaa

2014

Tässä lehdessä on käyty kiivasta ja provokatiivistakin keskustelua suhteellisuusteoriasta. Edellisessä numerossa Juha Himanka (Tieteessä tapahtuu 3/2014) väittää, että Albert Einsteinin suhteellisuusteoria, erotuksena luonnontieteestä, on yksinomaan filosofiaa. Se ylittää hänen mukaansa luonnontieteen rajat pyrkiessään yleispätevään esitykseen todellisuudesta, ajasta ja avaruudesta. Hän myös pitää sitä fenomenologiseen tieteenkritiikkiinsä vedoten ongelmallisena. Toisaalta Kari Enqvist ja Syksy Räsänen (Tieteessä tapahtuu 3/2014) ovat korostaneet suhteellisuusteorian kiistatonta empiiristä tukea sekä siihen pohjaavan teknologian toimivuutta osoituksena teorian paikkansapitävyydestä. Esitän …

A Conceptual Restructuring of Spatial Motion Expressions in Chinese L2

2018

This paper focuses on the patterns in the encoding of spatial motion events that play a major role in the acquisition of these type of expressions. The goal is to single out the semantic contribution of the linguistic items which surface in Chinese locative constructions. In this way, we intend to provide learners with an account of the spatial representation encoded in the Chinese language. In fact, Chinese grammar is often perceived as idiosyncratic, thus generating a frustration that turns into learned helplessness (Maier and Seligman, 1976). We will analyze Talmy (2000a,b) framework under the light of investigations such as Landau and Jackendoff (1993), Svenonius (2004, 2006, 2007), and…

Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network

2019

Gravitational wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event was detected in this sear…

All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems

2021

Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most s…

Dynamics of boson stars and fermion-boson stars: a numerical-relativity panorama

2022

Los albores de la astronomía de ondas gravitacionales, actualmente liderada por la Colaboración LIGO-Virgo-KAGRA, abren un nuevo canal para inspeccionar la verdadera naturaleza de los objetos compactos oscuros. Los miembros más convincentes de esta categoría son los agujeros negros, de los que se cree ampliamente que están bien descritos por la métrica de Kerr cerca del equilibrio. Se han propuesto varias posibilidades teóricas más exóticas, denominadas imitadores de agujeros negros, ya que sus propiedades y dinámica se parecen en ciertos aspectos a las de los agujeros negros. Entre esos objetos compactos oscuros alternativos, las estrellas bosónicas, descritas por un campo escalar o vector…

2020

Visually induced motion sickness is an unpleasant but common side-effect of many simulations and VR-applications. We investigated whether an earth-fixed reference frame provided in the simulation is able to reduce motion sickness. To do so, we created a moving starfield that did not contain any indicators of the spatial orientation of the observer. The observer wore a head-mounted display (HTC Vive) and was simulated to move through the randomly oscillating starfield, a time-to-contact task had to be carried out. Two colored stars on collision course with each other had to be spotted, then they disappeared and the time of their collision had to be judged. Eye-movements, task performance, an…

Saliency Based Aesthetic Cut of Digital Images

2013

Aesthetic cut of photos is a process well known to professional photographers. It consists of cutting the original photo to remove less relevant parts close to the borders leaving in this way the interesting subjects in a position that is perceived by the observer as more pleasant. In this paper we propose a saliency based technique to automatically perform aesthetic cut in images. We use a standard method to estimate the saliency map and propose some post processing on the map to make it more suitable for our scope. We then apply a greedy algorithm to determine the cut (i.e. the most important part of the original image) both in the cases of free and fixed aspect ratio. Experimental result…

Electromagnetic spectrum and color vision

2004

In most of occasions the maps, drawings and printed images are elaborated thinking that the observer will visualize them with illuminants like the light of the day. With these illuminants, for example the CIE D/sub 65/, we can distinguish the great quantity of colors that it is capable the human eye. But if the illuminant has a very different spectrum than the light of day, for example the light of acetylene, the number of colors that we are able to distinguish can decrease drastically.

International place branding through sporting events: a British perspective of the 2008 Beijing Olympics

2012

International audience; The goal of this study is to examine if hosting major sporting events represents a relevant strategy to brand a place ‘internationally’ through brand association transfer and to identify whether or not it should be seen as co-branding process. Based on social representation theory and an abductive research strategy, a survey was carried out among British citizens to identify their opinions about the Olympic Games and the city of Beijing following the organisation of the Games in August 2008. The content and the structure of the social representations were analysed and then compared to determine whether or not a double transfer of associations occurred between the pla…

Airy-function approach to binary black hole merger waveforms: The fold-caustic diffraction model

2022

From numerical simulations of the Einstein equations, and also from gravitational wave observations, the gravitational wave signal from a binary black hole merger is seen to be simple and to possess certain universal features. The simplicity is somewhat surprising given that non-linearities of general relativity are thought to play an important role at the merger. The universal features include an increasing amplitude as we approach the merger, where transition from an oscillatory to a damped regime occurs in a pattern apparently oblivious to the initial conditions. We propose an Airy-function pattern to model the binary black hole (BBH) merger waveform, focusing on accounting for its simpl…