6,312 research outputs found
The Cosmic Ray p+He energy spectrum in the 3-3000 TeV energy range measured by ARGO-YBJ
The ARGO-YBJ experiment is a full coverage air shower detector operated at
the Yangbajing International Cosmic Ray Observatory. The detector has been in
stable data taking in its full configuration since November 2007 to February
2013. The high altitude and the high segmentation and spacetime resolution
offer the possibility to explore the cosmic ray energy spectrum in a very wide
range, from a few TeV up to the PeV region. The high segmentation allows a
detailed measurement of the lateral distribution, which can be used in order to
discriminate showers produced by light and heavy elements. In this work we
present the measurement of the cosmic ray light component spectrum in the
energy range 3-3000 TeV. The analysis has been carried out by using a
two-dimensional unfolding method based on the Bayes' theorem.Comment: Talk given at RICAP14 conferenc
Entanglement in fermionic systems
The anticommuting properties of fermionic operators, together with the
presence of parity conservation, affect the concept of entanglement in a
composite fermionic system. Hence different points of view can give rise to
different reasonable definitions of separable and entangled states. Here we
analyze these possibilities and the relationship between the different classes
of separable states. We illustrate the differences by providing a complete
characterization of all the sets defined for systems of two fermionic modes.
The results are applied to Gibbs states of infinite chains of fermions whose
interaction corresponds to a XY-Hamiltonian with transverse magnetic field.Comment: 13 pages, 3 figures, 4 table
Environmental impact related to electricity production:comparision of Finland and Sweden
Abstract. Environmental issues have been on the topic lately. Particular attention is paid to emissions which cause global warming. Electricity production causes significant amount of emissions. Therefore, switching to cleaner production is environmentally beneficial. None of the methods are fully clean but emissions are low in some production modes. These include such methods as electricity produced by the sun and wind, as well as nuclear energy. Fossil fuel resources are in short supply. For that reason, it is important to produce electricity from such renewable sources as wind-, solar- and bioenergy plants.
Electricity production and consumption occur simultaneously. For that reason, electricity production should match with consumption. Some of the electricity production methods depends on the weather and its sometimes unavailable. Electricity production and consumption is balanced by reserve power plants, like hydro power and imported electricity. Therefore, the electricity coming from the outlet is mixed electricity which contains electricity produced by different methods. In such the Nordic countries as Finland and Sweden, winter is cold and long which cause its own challenges to power generation.
This bachelor’s thesis compares the differences of Finnish and Swedish electricity production and clarifies which electricity mix is cleaner. In addition, the network and markets in the Nordic countries will be introduced. Bachelor’s thesis also explains shortly different electricity production methods and emissions caused by them.
Geographically Finland and Sweden are very identical, however, there are many differences in their power generation. Finland utilize a plenty amount of imported electricity. A large part of imported electricity comes from Sweden, because Sweden generates electricity beyond its needs. Sweden produces more electricity from renewable energy than Finland. Also, emissions from power generation in Sweden are lower than in Finland. Future plans with electricity production are different since Sweden is eliminating the use of nuclear energy, but Finland is increasing it. Both countries aim to reduce greenhouse gas emissions.Sähköntuotantoon liittyvät ympäristövaikutukset : vertailu Suomen ja Ruotsin välillä. Tiivistelmä. Ilmastoasiat ovat olleet viime aikoina paljon esillä. Etenkin päästöihin pyritään kiinnittämään huomiota entistä enemmän, koska ne vaikuttavat ilmastonmuutokseen. Sähköntuotanto aiheuttaa paljon päästöjä, joten ympäristön kannalta olisi hyvä siirtyä puhtaisiin tuotantomenetelmiin. Mikään menetelmä ei kuitenkaan ole täysin päästötön, mutta päästöt ovat vähäisiä osassa tuotantomuodoista. Näitä ovat esimerkiksi tuulen ja auringon kautta tuotettu sähkö, sekä ydinenergia. Fossiiliset luonnonvarat loppuvat myös ajallaan, joten sähköntuotannon olisi hyvä olla mahdollisimman uusiutuvaa, kuten esimerkiksi tuuli-, aurinko- ja bioenergialla tuotettu sähkö.
Sähköä tuotetaan samaan aikaan kuin sitä käytetään. Tämän takia sähköntuotannon on vastattava sen hetkistä kulutusta. Osa sähköntuotannon menetelmistä riippuu paljolti säästä, eikä siksi ole aina saatavilla. Sähköntuotantoa ja -kulutusta pidetään tasapainossa säätövoiman avulla, näitä ovat esimerkiksi vesivoima ja tuontisähkö. Niillä voidaan reagoida nopeasti muuttuvaan sähköntarpeeseen. Pistorasiasta tuleva sähkö on siis sekasähköä, joka sisältää eri menetelmin tuotettua sähköä. Pohjoismaissa, kuten Suomessa ja Ruotsissa, talvi ovat pitkä ja kylmä, joten sähköntuotannossa on omat haasteensa.
Tässä kandidaatin työssä vertaillaan Suomen ja Ruotsin välisiä eroja sähköntuotannossa, sekä selvitetään, kumman sähkö on puhtaampaa. Lisäksi tutustutaan sähköverkkoihin ja -markkinoihin pohjoismaissa. Kandidaatin työ käsittelee myös lyhyesti erilaisia sähköntuotanto menetelmiä, sekä niiden aiheuttamia päästöjä.
Maantieteellisesti Suomi ja Ruotsi ovat hyvin samanlaisia, mutta sähköntuotannossa on paljon eroja. Suomessa käytetään paljon tuontisähköä. Tuontisähköstä iso osa tulee Ruotsista, koska Ruotsi tuottaa sähköä yli tarpeidensa. Ruotsissa tuotetaan sähköä enemmän uusiutuvasta energiasta kuin suomessa. Lisäksi, Ruotsin sähköntuotannon päästöt ovat alhaisempia kuin Suomen. Tulevaisuuden Ruotsi on irrottautumasta ydinenergian käytöstä, mutta suomessa sitä ollaan lisäämässä. Molemmat maat pyrkivät vähentämään kasvihuonekaasuja
Experimental determination of molar polarizability of nitrogen by a multi-reflection inteferometric technique
A novel optical pressure standard, based on a multi-reflection interferometric technique, has been recently developed. It is based on the measurement of the refractive index of a gas through an unbalanced homodyne interferometer (UINT) and is able to measure pressure with a relative standard uncertainty of 10 ppm at 100 kPa [1]. In this work, the interferometer was used to measure the molar polarizability of nitrogen, which resulted in agreement with recent previous determinations, paving the way for using photonic pressure standards as accurate and fast transfer standards of the pascal
Le imprese femminili in Italia: i risultati di un'indagine esplorativa
Entrepreneurship has usually been considered a male-dominated activity. In 2012, however, 224mout of 400mentrepreneurs worldwide were women (GEM 2012).Female entrepreneurship therefore clearly represents an important component of the business sector at global level. To date, however, the scope of research on such a relevant topic is still confined to the US and Anglo-Saxon countries. Also, academic research on Italian female entrepreneurship is very limited, despite Italy has the highest number of female-owned firms in Europe (Eurostat, 2013). This paper thus contributes to fill this research gap by investigating the characteristics, the main problems and motivations of 310 Italian female-owned firms
Normal form decomposition for Gaussian-to-Gaussian superoperators
In this paper we explore the set of linear maps sending the set of quantum
Gaussian states into itself. These maps are in general not positive, a feature
which can be exploited as a test to check whether a given quantum state belongs
to the convex hull of Gaussian states (if one of the considered maps sends it
into a non positive operator, the above state is certified not to belong to the
set). Generalizing a result known to be valid under the assumption of complete
positivity, we provide a characterization of these Gaussian-to-Gaussian (not
necessarily positive) superoperators in terms of their action on the
characteristic function of the inputs. For the special case of one-mode
mappings we also show that any Gaussian-to-Gaussian superoperator can be
expressed as a concatenation of a phase-space dilatation, followed by the
action of a completely positive Gaussian channel, possibly composed with a
transposition. While a similar decomposition is shown to fail in the multi-mode
scenario, we prove that it still holds at least under the further hypothesis of
homogeneous action on the covariance matrix
Women entrepreneurs and innovation: Retrospect and prospect
This paper answers the call for a deeper understanding of innovation issues in relation to female entrepreneurship. In doing so, it offers a comprehensive and updated picture of the state of the art of management research on innovation in women-owned firms. Specifically, by conducting a systematic literature review, which is widely used in management studies, and by using rigorous and replicable criteria, this manuscript seeks to understand this crucial intersection through an in depth investigation of 48 papers, thus addressing a relevant gap that exists in literature to date. Results demonstrate that, despite the increasing attention given to female entrepreneurship and innovation at both political and social levels, due to their key role worldwide, a significant gap in the integration of these two areas still exists. Thus, it is time for scholars to reimagine the concept of innovation and to explore the untapped potential within female entrepreneurship, redefining and bringing to light all the facets that innovation may have. The study provides avenues on which scholars should focus in order to help policy makers to work towards fostering a more inclusive and dynamic entrepreneurial ecosystem that empowers women to drive innovation and economic growth
The social psychology of collective victimhood
Collective victimhood, which results from the experience of being targeted as members of a group, has powerful effects on individuals and groups. The focus of this Special Issue is on how people respond to collective victimhood and how these responses shape intergroup relations. We introduce the Special Issue with an overview of emerging social psychological research on collective victimhood. To date, this research has focused mostly on destructive versus positive consequences of collective victimhood for relations with an adversary group, and examined victim groups' needs, victim beliefs, and underlying social identity and categorization processes. We identify several neglected factors in this literature, some of which are addressed by the empirical contributions in the current issue. The Special Issue offers novel perspectives on collective victimhood, presenting findings based on a diverse range of methods with mostly community samples that have direct and vicarious experiences of collective harm in different countries
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