Search results for " observation"
showing 10 items of 441 documents
Police violence in West Africa : Perpetrators' and ethnographers' dilemmas
2012
This article explores the use of violence by police officers and gendarmes in Ghana and Niger. We analyse how popular discourses, legal and organizational conditions frame the police use of violence. Acts of violence by police are situated in this inconsistent framework and can be seen as legal and appropriate, despicable and brutal, or as useful and morally legitimate. Thus, every time the police use violence, they face a major dilemma: legally and morally justified violence can be a source of long-term legitimacy; but because of multiple possible readings of a certain situation (according to different, conflicting moral and legal discourses), the very same action has potentially delegiti…
Rewriting Oromo History in the North: Diasporic Discourse about National Identity and Democracy in Ethiopia
2015
This article analyzes the way the Oromo intellectuals living in diaspora have reflected on and positioned themselves in the ethno-political conflict and related debate between the dominant Amharic- and Tigrinya-speaking “Abyssinian” groups and the descendants of the various Oromo groups, which were conquered by the former during the nineteenth century. Even though they are the largest ethnic group in Ethiopia, a large part of the Oromo perceive themselves as discriminated against and exploited by the groups holding political power, and many have fled the country. In the debate, the Oromo diaspora has had an important role. Theoretically, the article takes off from the concept of “orientati…
La verificació audiovisual en el procés d’evolució de les redaccions televisives: Al Jazeera i el trànsit del satèl·lit a l’estructura de núvol
2021
With the spread of the digital sphere and the proliferation of images from indirect sources that can be accessed by systems and users, verification routines have become essential to ensure media corporations' credibility. The advances in artificial intelligence which allow automated fact-checking (AFC) initiatives to be created help detect falsehoods, but they do not eliminate the need for human intervention. On the contrary, information professionals are necessary, and their functions increasingly include procedures such as mediating in videos and images. This study analyses the evolution of verification routines in audiovisual journalism and how new techniques have influenced the percepti…
Performing ethnography and ethnicity : an early documentation of Finnish immigrants in Nordiska museet
2010
This article discusses the first project of the Nordic Museum in Stockholm, Sweden, dealing with immigrants. It was carried out between 1972 and 1990, and it produced material based on interviews, participant observation, photographs and other written and visual sources. The article first examines why and how this extensive research project was carried out and then discusses the documentation project as performance. The project was an early attempt to document the contemporary lives of people through fieldwork, although the original aim of this pioneering project was merely to create and preserve ethnic identity by documenting “authentic” Finnish characteristics. Thus, it is a good example …
Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the $Kepler$ 2 Observations
2019
Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically-confirmed type Ia supernova (SN Ia) observed in the $Kepler$ field. The $Kepler$ data revealed an excess emission in its early light curve, allowing to place interesting constraints on its progenitor system (Dimitriadis et al. 2018, Shappee et al. 2018b). Here, we present extensive optical, ultraviolet, and near-infrared photometry, as well as dense sampling of optical spectra, for this object. SN 2018oh is relatively normal in its photometric evolution, with a rise time of 18.3$\pm$0.3 days and $\Delta$m$_{15}(B)=0.96\pm$0.03 mag, but it seems to have bluer $B - V$ colors. We construct the "uvoir" bolometric light curve hav…
FRIPON: a worldwide network to track incoming meteoroids
2020
Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile - hence precious - meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receiver…
Cloud masking and removal in remote sensing image time series
2017
Automatic cloud masking of Earth observation images is one of the first required steps in optical remote sensing data processing since the operational use and product generation from satellite image time series might be hampered by undetected clouds. The high temporal revisit of current and forthcoming missions and the scarcity of labeled data force us to cast cloud screening as an unsupervised change detection problem in the temporal domain. We introduce a cloud screening method based on detecting abrupt changes along the time dimension. The main assumption is that image time series follow smooth variations over land (background) and abrupt changes will be mainly due to the presence of clo…
Quantifying Vegetation Biophysical Variables from Imaging Spectroscopy Data: A Review on Retrieval Methods
2019
An unprecedented spectroscopic data stream will soon become available with forthcoming Earth-observing satellite missions equipped with imaging spectroradiometers. This data stream will open up a vast array of opportunities to quantify a diversity of biochemical and structural vegetation properties. The processing requirements for such large data streams require reliable retrieval techniques enabling the spatiotemporally explicit quantification of biophysical variables. With the aim of preparing for this new era of Earth observation, this review summarizes the state-of-the-art retrieval methods that have been applied in experimental imaging spectroscopy studies inferring all kinds of vegeta…
GW170817: Measurements of Neutron Star Radii and Equation of State
2018
On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation…
Tests of General Relativity with GW170817
2019
The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in presence of matter. In this paper, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polari…