995 resultados para Gamma chain
Resumo:
Tämän työn tarkoituksena oli kehittää toimintamalli, joka yhdenmukaistaisi Kone Elevators:in modernisointiliikealueen logistiset käytännöt. Toimintamalli luotiin kartoittamalla euroopan maayksiköiden nykyisiä logistisia käytäntöjä sekä perehtymällä asiaankuuluvaan kirjallisuuteen, case study:ihin sekä sähköisiin artikkeleihin. Tärkeää osaa työssä esittivät maayksiköiden sekä Koneen toimittajayksiköiden edustajien haastattelut. Haastatteluiden tuloksia vertailtiin ja analysoitiin. Niiden pohjalta huomattiin, että logistiset toimintatavat vaihtelevat maittain. Ongelmat ovat kuitenkin hyvin samanlaisia; tiedonkulun katkot toimitusprosessin aikana. Muiden Koneen liikealueiden toimintatapoja tutkimalla, haastattelujen tuloksia käyttämällä sekä kirjallisuustutkimuksen pohjalta muodostettiin näkemys parhaasta toimintatapamallista. Modernisointiliikealueen toimitusprosessi tullee perustumaan keskitettyyn ohjaukseen, mutta paikalliseen koordinointiin. Se tullee hyväksikäyttämään ulkoistetun logistiikan tarjoamia mahdollisuuksia sekä sähköistä tiedonsiirtoa. Fyysiselle siirrolle tarjotaan kolmea vaihtoehtoa, joista maayksiköt voivat valita tilanteeseen parhaiten sopivan.
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Tutkielman tavoitteena on tarkastella letkuventtiilien tilaus-toimitusketjua ja selvittää, kuinka se muodostuu. Tavoitteena on laatia selvitys yrityksen tilaus-toimitusketjun muodostumisen vaiheista yrityksen sisäiseen käyttöön ja tutkia, kuinka ketjua voitaisiin parantaa, jotta tulevaisuudessa asiakkaita voitaisiin palvella paremmin ja joustavammin. Tutkimusongelmaa lähestytään prosessiajattelun näkökulmasta ja tutkielmassa käytetään kvalitatiivista tutkimusmenetelmää, jonka pääasiallisena tiedonkeruuvälineenä on vapaamuotoiset haastattelut, yrityksen dokumenttien tutkiminen ja analysointi sekä yrityksen toiminnan havainnointi. Tilaus-toimitusketjun parantaminen edellyttää yritykseltä ja sen edustajilta asiakkaiden ostokäyttäytymisen ohjaamista, tiedon avointa ja oikea-aikaista jakamista kaikille sitä tarvitseville sekä kulttuurierojen huomioon ottamista. Erityisesti tilaus-toimitusketjun alkuvaiheisiin tulisi panostaa tulevaisuudessa, sillä monet ongelmat syntyvät tutkimuksen mukaan toimitusketjun alkupuolella.
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Microquasars are stellar x-ray binaries that behave as a scaled down version of extragalactic quasars. The star LS 5039 is a new microquasar system with apparent persistent ejection of relativistic plasma at a 3 kiloparsec distance from the sun. It may also be associated with a gamma-ray source discovered by the Energetic Gamma Ray Experiment Telescope (EGRET) on board the COMPTON-Gamma Ray Observatory satellite. Before the discovery of LS 5039, merely a handful of microquasars had been identified in the Galaxy, and none of them was detected in high-energy gamma-rays.
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The purpose of this thesis was to investigate Job Definition Format (JDF) and how it could be used in printing house's systems. JDF is a very new information exchange standard, and it gives a lot of opportunities to the printing industry. JDF is the first standard, that has an ability to carry a print job from genesis through completion. Besides, JDF has an ability to bridge the communication gap between production and management information services. In the study of JDF we focused on examining how JDF will effect on printing industry .The thesis also examines printing houses's systems ability to work with JDF standard. The result of the study is a comprehensive picture, what is JDF. We also researched the system developers' visions, how JDF will effect on their products in the future.
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Context.Massive stars form in dense and massive molecular cores. The exact formation mechanism is unclear, but it is possible that some massive stars are formed by processes similar to those that produce the low-mass stars, with accretion/ejection phenomena occurring at some point of the evolution of the protostar. This picture seems to be supported by the detection of a collimated stellar wind emanating from the massive protostar IRAS 16547-4247. A triple radio source is associated with the protostar: a compact core and two radio lobes. The emission of the southern lobe is clearly non-thermal. Such emission is interpreted as synchrotron radiation produced by relativistic electrons locally accelerated at the termination point of a thermal jet. Since the ambient medium is determined by the properties of the molecular cloud in which the whole system is embedded, we can expect high densities of particles and infrared photons. Because of the confirmed presence of relativistic electrons, inverse Compton and relativistic Bremsstrahlung interactions are unavoidable. Aims.We aim to make quantitative predictions of the spectral energy distribution of the non-thermal spots generated by massive young stellar objects, with emphasis on the particular case of IRAS 16547-4247. Methods.We study the high-energy emission generated by the relativistic electrons which produce the non-thermal radio source in IRAS 16547-4247. We also study the result of proton acceleration at the terminal shock of the thermal jet and make estimates of the secondary gamma rays and electron-positron pairs produced by pion decay. Results.We present spectral energy distributions for the southern lobe of IRAS 16547-4247, for a variety of conditions. We show that high-energy emission might be detectable from this object in the gamma-ray domain. The source may also be detectable in X-rays through long exposures with current X-ray instruments. Conclusions.Gamma-ray telescopes such as GLAST, and even ground-based Cherenkov arrays of new generation can be used to study non-thermal processes occurring during the formation of massive stars.
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Among unidentified gamma-ray sources in the galactic plane, there are some that present significant variability and have been proposed to be high-mass microquasars. To deepen the study of the possible association between variable low galactic latitude gamma-ray sources and microquasars, we have applied a leptonic jet model based on the microquasar scenario that reproduces the gamma-ray spectrum of three unidentified gamma-ray sources, 3EG J1735-1500, 3EG J1828+0142 and GRO J1411-64, and is consistent with the observational constraints at lower energies. We conclude that if these sources were generated by microquasars, the particle acceleration processes could not be as efficient as in other objects of this type that present harder gamma-ray spectra. Moreover, the dominant mechanism of high-energy emission should be synchrotron self-Compton (SSC) scattering, and the radio jets may only be observed at low frequencies. For each particular case, further predictions of jet physical conditions and variability generation mechanisms have been made in the context of the model. Although there might be other candidates able to explain the emission coming from these sources, microquasars cannot be excluded as counterparts. Observations performed by the next generation of gamma-ray instruments, like GLAST, are required to test the proposed model.
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Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a strong concentration toward the inner spiral arms of the Galaxy. Variability, spectral and correlation analysis indicate that this population is not homogeneous. In particular, there is a subgroup of sources that display clear variability in their gamma-ray fluxes on timescales from days to months. Following the proposal by Kaufman Bernad\'o et al. (2002), we suggest that this group of sources might be high-mass microquasars, i.e. accreting black holes or neutron stars with relativistic jets and early-type stellar companions. We present detailed inhomogeneous models for the gamma-ray emission of these systems that include both external and synchrotron self-Compton interactions. We have included effects of interactions between the jet and all external photon fields to which it is exposed: companion star, accretion disk, and hot corona. We make broadband calculations to predict the spectral energy distribution of these objects from radio up to GeV energies. The results and predictions can be tested by present and future gamma-ray instruments like INTEGRAL, AGILE, and GLAST.
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The possible associations between the microquasars LS 5039 and LS I +61 303 and the EGRET sources 3EG J1824-1514 and 3EG J0241+6103 suggest that microquasars could also be sources of high-energy gamma-rays. In this work, we present a detailed numerical inverse Compton (IC) model, based on a microquasar scenario, that reproduces the high-energy gamma-ray spectra and variability observed by EGRET for the mentioned sources. Our model considers a population of relativistic electrons entrained in a cylindrical inhomogeneous jet that interact through IC scattering with both the radiation and the magnetic fields.
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Tämä tutkimus pyrkii selvittämään, miten toimitusketjun suorituskykyä voidaan mitata kohdeyrityksessä. Supply Chain Council (SCC) on vuonna 1996 kehittänyt Supply Chain Operations Reference (SCOR) – mallin, joka mahdollistaa myös suorituskyvyn mittaamisen. Tämän tutkimuksen tarkoituksena on soveltaa SCOR-mallin suorituskyvyn mittausmallia kohdeyrityksessä. Työ on kvalitatiivinen tapaustutkimus. Työn teoriaosassa on pääasiallisesti käsitelty toimitusketjua ja suorituskyvyn mittaamista koskevaa kirjallisuutta. Mittausjärjestelmän luominen alkaa kohdeyrityksen esittelyllä. SCOR – mallin mittarit on kohdeyrityksessä rakennettu SCC:n ehdotusten mukaisesti, jotta mittareiden tulokset olisivat käyttökelpoisia myös benchmarkkausta varten. Malli sisältää 10 SCOR – mittaria, sekä muutamia muita Haltonin omia mittareita. Lopputuloksena voidaan nähdä, että SCOR – malli antaa hyvän yleiskuvan toimitusketjun suorituskyvystä, mutta kohdeyrityksessä on silti tarvetta kehittää edelleen informatiivisempia mittareita, jotka antaisivat yksityiskohtaisempaa tietoa kohdeyrityksen johdolle.
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We prove that for a topological operad $P$ the operad of oriented cubical singular chains, $C^{\ord}_\ast(P)$, and the operad of simplicial singular chains, $S_\ast(P)$, are weakly equivalent. As a consequence, $C^{\ord}_\ast(P\nsemi\mathbb{Q})$ is formal if and only if $S_\ast(P\nsemi\mathbb{Q})$ is formal, thus linking together some formality results which are spread out in the literature. The proof is based on an acyclic models theorem for monoidal functors. We give different variants of the acyclic models theorem and apply the contravariant case to study the cohomology theories for simplicial sets defined by $R$-simplicial differential graded algebras.
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Background: Gamma Knife surgery (GKS) for vestibular schwannomas (VS) has a long-term clinical and scientific track record. After a period of de-escalation of dose prescription, results show a high rate of tumor control with improvement of clinical outcome (less than 1% facial palsy, 50-70% hearing preservation). Currently, there is controversial data about the active early treatment of intracanalicular (Koos I) VS. Methods: We prospectively analyzed 208 VS, focusing on 42 Koos I patients treated with GKS as first intention in Lausanne University Hospital, between July 2010 and February 2015. We concentrated on patient, tumor, and dosimetric characteristics. Special attention was given on the dose to the cochlea and its impact in maintaining serviceable hearing. Results: The mean follow-up period was 1.7 years (range 0.6-4.2). Twenty-six (61.9%) were females and 16 (38.1%) males. Preoperative serviceable hearing was present in 33 (78.57%) patients. The mean maximal diameter was 7.7 (5-10). The median target volume at the moment of GKS was 90 mm3 (range 17-317). The median prescription isodose volume was 118 mm3 (range 37-603). The median marginal dose administrated was 12 Gy (range 11-12). The median number of shots was 2 (range 1-9). The median isodose prescription was 50% (range 45-80%). The median maximal dose received by the cochlea in patients in GR class 1 and 2 was 4.2 Gy (mean 4.4 Gy, range 1.8-7.6). Our preliminary results showed 98% tumor control, with 30% shrinkage on MRI. The actuarial probability of keeping the same audition class for those with functional hearing at GKS was 80% at 3 years; the probability of keeping a functional hearing was more than 90%. A paraclinical evolution (on MRI and/or audiometry) at the time diagnosis, before GKS, was associated with a less good prognosis (p < 0.05). Conclusions: Our preliminary data suggest that Koos I patients should be treated early with GKS, before tumor growth, and/or hearing deterioration, as they have the highest probability of hearing preservation. The results in terms of functional outcome seemed comparable to, or even better than, the other Koos classes (i.e., larger lesions).
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Objectives: We present the retrospective analysis of a single-institution experience for radiosurgery (RS) in brain metastasis (BM) with Gamma Knife (GK) and Linac. Methods: From July 2010 to July 2012, 28 patients (with 83 lesions) had RS with GK and 35 patients (with 47 lesions) with Linac. The primary outcome was the local progression-free survival (LPFS). The secondary outcome was the overall survival (OS). Apart a standard statistical analysis, we included a Cox regression model with shared frailty, to modulate the within-patient correlation (preliminary evaluation showed a significant frailty effect, meaning that the correlation within patient could be ignored). Results: The mean follow-up period was 11.7 months (median 7.9, 1.7-22.7) for GK and 18.1 (median 17, 7.5-28.7) for Linac. The median number of lesions per patient was 2.5 (1-9) in GK compared with 1 (1-3) in Linac. There were more radioresistant lesions (melanoma) and more lesions located in functional areas for the GK group. The median dose was 24 Gy (GK) compared with 20 Gy (Linac). The LPFS actuarial rate was as follows: for GK at 3, 6, 9, 12, and 17 months: 96.96, 96.96, 96.96, 88.1, and 81.5%, and remained stable till 32 months; for Linac at 3, 6, 12, 17, 24, and 33 months, it was 91.5, 91.5, 91.5, 79.9, 55.5, and 17.1%, respectively (p = 0.03, chi-square test). After the Cox regression analysis with shared frailty, the p-value was not statistically significant between groups. The median overall survival was 9.7 months for GK and 23.6 months for Linac group. Uni- and multivariate analysis showed a lower GPA score and noncontrolled systemic status were associated with lower OS. Cox regression analysis adjusting for these two parameters showed comparable OS rate. Conclusions: In this comparative report between GK and Linac, preliminary analysis showed that more difficult cases are treated by GK, with patients harboring more lesions, radioresistant tumors, and highly functional located. The groups look, in this sense, very heterogeneous at baseline. After a Cox frailty model, the LPFS rates seemed very similar (p < 0.05). The OS was similar, after adjusting for systemic status and GPA score (p < 0.05). The technical reasons for choosing GK instead of Linac were the anatomical location related to highly functional areas, histology, technical limitations of Linac movements, especially lower posterior fossa locations, or closeness of multiple lesions to highly functional areas optimal dosimetry with Linac
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We present preliminary results of a campaign undertaken with different radio interferometers to observe a sample of the most variable unidentified EGRET sources. We expect to detect which of the possible counterparts of the gamma-ray sources (any of the radio emitters in the field) varies in time with similar timescales as the gamma-ray variation. If the gamma-rays are produced in a jet-like source, as we have modelled theoretically, synchrotron emission is also expected at radio wavelengths. Such radio emission should appear variable in time and correlated with the gamma-ray variability.