| 1. |
- Adlarson, Patrik, et al.
(författare)
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Abashian-Booth-Crowe Effect in Basic Double-Pionic Fusion : A New Resonance?
- 2011
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 106:24, s. 242302-
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Tidskriftsartikel (refereegranskat)abstract
- We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn -> d pi(0)pi(0) over the full energy region of the ABC effect, a pronounced low-mass enhancement in the pi pi-invariant mass spectrum. The measurements, which cover also the transition region to the conventional t- channel Delta Delta process, were performed with the upgraded WASA detector setup at COSY. The data reveal the Abashian-Booth-Crowe effect to be uniquely correlated with a Lorentzian energy dependence in the integral cross section. The observables are consistent with a narrow resonance with m = 2.37 GeV, Gamma approximate to 70 MeV and I(J(P)) = 0(3(+)) in both pn and Delta Delta systems. Necessary further tests of the resonance interpretation are discussed.
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| 2. |
- Cederlund, Harald, et al.
(författare)
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Utveckling av metod för att bedöma behovet av ogräsbekämpning i spår
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A system for weed management on railway embankments that is both adapted to the environment and efficient in terms of resources requires knowledge and understanding about the growing conditions of vegetation so that methods to control its growth can be adapted accordingly. Automated records could complement present-day manual inspections and over time come to replace these. One challenge is to devise a method that will result in a reasonable breakdown of gathered information that can be managed rationally by affected parties and, at the same time, serve as a basis for decisions with sufficient precision. The project examined two automated methods that may be useful for the Swedish Transport Administration in the future: 1) A machine vision method, which makes use of camera sensors as a way of sensing the environment in the visible and near infrared spectrum; and 2) An N-Sensor method, which transmits light within an area that is reflected by the chlorophyll in the plants. The amount of chlorophyll provides a value that can be correlated with the biomass. The choice of technique depends on how the information is to be used. If the purpose is to form a general picture of the growth of vegetation on railway embankments as a way to plan for maintenance measures, then the N-Sensor technique may be the right choice. If the plan is to form a general picture as well as monitor and survey current and exact vegetation status on the surface over time as a way to fight specific vegetation with the correct means, then the machine vision method is the better of the two. Both techniques involve registering data using GPS positioning. In the future, it will be possible to store this information in databases that are directly accessible to stakeholders online during or in conjunction with measures to deal with the vegetation. The two techniques were compared with manual (visual) estimations as to the levels of vegetation growth. The observers (raters) visual estimation of weed coverage (%) differed statistically from person to person. In terms of estimating the frequency (number) of woody plants (trees and bushes) in the test areas, the observers were generally in agreement. The same person is often consistent in his or her estimation: it is the comparison with the estimations of others that can lead to misleading results. The system for using the information about vegetation growth requires development. The threshold for the amount of weeds that can be tolerated in different track types is an important component in such a system. The classification system must be capable of dealing with the demands placed on it so as to ensure the quality of the track and other pre-conditions such as traffic levels, conditions pertaining to track location, and the characteristics of the vegetation. The project recommends that the Swedish Transport Administration: Discusses how threshold values for the growth of vegetation on railway embankments can be determined Carries out registration of the growth of vegetation over longer and a larger number of railway sections using one or more of the methods studied in the project Introduces a system that effectively matches the information about vegetation to its position Includes information about the growth of vegetation in the records that are currently maintained of the track’s technical quality, and link the data material to other maintenance-related databases Establishes a number of representative surfaces in which weed inventories (by measuring) are regularly conducted, as a means of developing an overview of the long-term development that can serve as a basis for more precise prognoses in terms of vegetation growth Ensures that necessary opportunities for education are put in place
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| 3. |
- Hallgren, Mattias, et al.
(författare)
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A hybrid model of competitive capabilities
- 2011
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Ingår i: International Journal of Operations & Production Management. - : Emerald. - 0144-3577 .- 1758-6593. ; 31:5, s. 511-526
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – The purpose of this paper is to present and test a new model for competitive capabilities.Traditionally, a cumulative model has been viewed as having one sequence of building competitivecapabilities in a firm in support of market needs, including quality, delivery, cost efficiency andflexibility. Although appealing as a conceptual model, empirical testing has not been able to fullysupport the cumulative model. This paper acknowledges the need for a hybrid approach to managingcapability progression. It brings together the literature on trade-offs, cumulative capabilities, andorder winners and qualifiers.Design/methodology/approach – A new hybrid approach for modelling competitive capabilities istested empirically using data from the high performance manufacturing (HPM) study, round 3,including three industries and seven countries – a total of 211 plants.Findings – The hybrid model shows significantly better fit with the data from the sample than thecumulative models suggested by previous literature. Empirical support is found for the traditionalperception that a high level of quality is a prerequisite for a high level of delivery performance.However, cost efficiency and flexibility do not exhibit a cumulative pattern. Instead, the results showthat they are developed in parallel. The findings suggest that a balance between cost efficiency andflexibility is built upon high levels of quality and delivery performance.Research limitations/implications – Since we limit the empirical investigation to three industriesand seven countries, it would be interesting to extend the testing of this model to more industries andcountries. This research shows that combining perspectives and insights from different researchstreams – in this case, trade-off theory and the concepts of cumulative capabilities, and order winnersand qualifiers – can be fruitful.Practical implications – The results of this paper provides managers with guidelines concerningthe configuration of competitive capabilities. First, a qualifying level of quality needs to be attained,followed by a qualifying level of delivery. Then, a balance between potential order winners, i.e. costefficiency and flexibility, needs to be attained.Originality/value – This paper presents a new approach to modelling competitive capabilities thatsynthesises previous research streams and perspectives from cumulative capabilities, contestingcapabilities (trade-offs), and order winners and qualifiers.
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| 4. |
- Hallgren, Mattias, et al.
(författare)
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Competitive capabilities : a contingency perspective
- 2007
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Ingår i: Journal of Operations Management. - 0272-6963 .- 1873-1317.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we present and test an alternative model for competitive capabilities.Traditionally, a cumulative model has been viewed as having one sequence of buildingoperations capabilities in a firm in support of market needs, including quality,delivery, cost efficiency and flexibility. Although appealing as a conceptual model,empirical testing has not been able to fully support the cumulative model. This paperacknowledges the need for differentiated approaches to managing capability indifferent operating environments. The competitive capability model that is presented istested empirically using data from the High Performance Manufacturing (HPM) study,including three industries and seven countries – a total of 211 plants. The results showthat there is empirical support for differentiating the competitive capabilities; firmsproducing to stock follow a path of quality, delivery and cost, whereas those producingto customer order exhibit a capability path in the order of quality, delivery andflexibility. Thus, while quality and delivery are common, cost and flexibility acts asdifferentiators contingent upon the manufacturing environment.
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| 5. |
- Laskar, Tanmoy, et al.
(författare)
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The Radio to GeV Afterglow of GRB 221009A
- 2023
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 946:1
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Tidskriftsartikel (refereegranskat)abstract
- GRB 221009A ($z=0.151$) is one of the closest known long $gamma$-ray bursts (GRBs). Its extreme brightness across all electromagnetic wavelengths provides an unprecedented opportunity to study a member of this still-mysterious class of transients in exquisite detail. We present multi-wavelength observations of this extraordinary event, spanning 15 orders of magnitude in photon energy from radio to $gamma$-rays. We find that the data can be partially explained by a forward shock (FS) from a highly-collimated relativistic jet interacting with a low-density wind-like medium. The jet's beaming-corrected kinetic energy ($E_K sim 4times10<^>{50}$ erg) is typical for the GRB population, but its opening angle ($sim2<^>{circ}$) is one of the narrowest. The radio and mm data provide strong limiting constraints on the FS model, but require the presence of an additional emission component. From equipartition arguments, we find that the radio emission is likely produced by a small amount of mass ($lesssim6times10<^>{-7} M_odot$) moving relativistically ($Gammagtrsim9$) with a large kinetic energy ($gtrsim10<^>{49}$ erg). However, the temporal evolution of this component does not follow prescriptions for synchrotron radiation from a single power-law distribution of electrons (e.g. in a reverse shock or two-component jet), or a thermal electron population, perhaps suggesting that one of the standard assumptions of afterglow theory is violated. GRB 221009A will likely remain detectable with radio telescopes for years to come, providing a valuable opportunity to track the full lifecycle of a powerful relativistic jet.
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