Neutron skin thickness in the droplet model with surface width dependence: Indications of softness of the nuclear symmetry energy

We analyze the neutron skin thickness in finite nuclei with the droplet model and effective nuclear interactions. The ratio of the bulk symmetry energy J to the so-called surface stiffness coefficient Q has in the droplet model a prominent role in driving the size of neutron skins. We present a correlation between the density derivative of the nuclear symmetry energy at saturation and the J/Q ratio. We emphasize the role of the surface widths of the neutron and proton density profiles in the calculation of the neutron skin thickness when one uses realistic mean-field effective interactions. Next, taking as experimental baseline the neutron skin sizes measured in 26 antiprotonic atoms along the mass table, we explore constraints arising from neutron skins on the value of the J/Q ratio. The results favor a relatively soft symmetry energy at subsaturation densities. Our predictions are compared with the recent constraints derived from other experimental observables. Though the various extractions predict different ranges of values, one finds a narrow window L���45-75 MeV for the coefficient L that characterizes the density derivative of the symmetry energy that is compatible with all the different empirical indications.

Friedman's Excess energy and the McMillan-Mayer theory of solutions:Thermodynamics

In his version of the theory of multicomponent systems, Friedman used the analogy which exists between the virial expansion for the osmotic pressure obtained from the McMillan-Mayer (MM) theory of solutions in the grand canonical ensemble and the virial expansion for the pressure of a real gas. For the calculation of the thermodynamic properties of the solution, Friedman proposed a definition for the"excess free energy" that is a reminder of the ancient idea for the"osmotic work". However, the precise meaning to be attached to his free energy is, within other reasons, not well defined because in osmotic equilibrium the solution is not a closed system and for a given process the total amount of solvent in the solution varies. In this paper, an analysis based on thermodynamics is presented in order to obtain the exact and precise definition for Friedman"s excess free energy and its use in the comparison with the experimental data.

Reproducibility of Vertebral Fracture Assessment Readings From Dual-energy X-ray Absorptiometry in Both a Population-based and Clinical Cohort: Cohen's and Uniform Kappa.

Vertebral fracture assessments (VFAs) using dual-energy X-ray absorptiometry increase vertebral fracture detection in clinical practice and are highly reproducible. Measures of reproducibility are dependent on the frequency and distribution of the event. The aim of this study was to compare 2 reproducibility measures, reliability and agreement, in VFA readings in both a population-based and a clinical cohort. We measured agreement and reliability by uniform kappa and Cohen's kappa for vertebral reading and fracture identification: 360 VFAs from a population-based cohort and 85 from a clinical cohort. In the population-based cohort, 12% of vertebrae were unreadable. Vertebral fracture prevalence ranged from 3% to 4%. Inter-reader and intrareader reliability with Cohen's kappa was fair to good (0.35-0.71 and 0.36-0.74, respectively), with good inter-reader and intrareader agreement by uniform kappa (0.74-0.98 and 0.76-0.99, respectively). In the clinical cohort, 15% of vertebrae were unreadable, and vertebral fracture prevalence ranged from 7.6% to 8.1%. Inter-reader reliability was moderate to good (0.43-0.71), and the agreement was good (0.68-0.91). In clinical situations, the levels of reproducibility measured by the 2 kappa statistics are concordant, so that either could be used to measure agreement and reliability. However, if events are rare, as in a population-based cohort, we recommend evaluating reproducibility using the uniform kappa, as Cohen's kappa may be less accurate.

Utilisation of Short Term Electricity Derivatives in Industrial Energy Management

Ty��n p����tavoite on selvitt���� kuinka erityisesti s��hk��n markkinahinnan ennustamiseen ja johdannaismarkkinoiden tiet��mykseen perustuva lyhyen t��ht��imen s��hk��johdannaisten hy��dynt��minen tapahtuu teollisessa energianhallinnassa. T��t�� aihetta l��hestyt����n luomalla prosessi lyhyen t��ht��imen s��hk��johdannaisten hy��dynt��miselle. Prosessi esitell����n ja selvitet����n aina l��ht��kohdista todelliseen kaupank��yntiin asti erillisen esimerkkitehtaan avulla.Lyhyen t��ht��imen s��hk��johdannaisten hy��dynt��minen teollisessa energianhallinnassa perustuu p����osin tulevaisuuden odotuksiin s��hk��n markkinahinnan kehittymisest�� sek�� tehtaiden operatiiviseen tilanteeseen. Operatiiviseen tilanteeseen perustuva lyhyen t��ht��imen s��hk��johdannaisten kaupank��ynti on p����asiassa pitk��n t��ht��imen suojausten sopeuttamista lyhyelle t��ht��imelle sopivaksi.Hinnan ennustamisella on suuri rooli lyhyen t��ht��imen s��hk��johdannaisten hy��dynt��misprosessissa. Ty��ss�� esitelty hinnan ennustamismalli on sopiva p��iv��- ja viikkotason Nord Poolin Elspot -systeemihinnan ennustamiseen. Elspot -systeemihinnan ennustamismalli on suunniteltu k��yt��nn��nl��heiseksi ja sen perustana ovat todelliset fysikaaliset ja mitattavat suureet. Futuurimarkkinatiet��mys on tarpeen lyhyen t��ht��imen johdannaisia k��ytett��ess��. Ty��ss�� tutkitaan yleisi�� markkinoiden odotuksia ja futuurimarkkinoiden tietoisuuden kehittymist�� koskien tulevaa vallitsevaa tilannetta. Ty��ss�� luodaan my��s ty��kalu, mik�� auttaa kaupan laatijaa muodostamaan suuntaa-antavat todenn��k��isyydet eri hintan��kemyksille ja paikallistamaan mahdolliset markkinoiden ep��todenn��k��iset hintaodotukset.Kokemukset Elspot -systeemihinnan ennustamismallin soveltamisesta ovat lupaavia. Lis��ksi havainnot futuurimarkkinoiden k��ytt��ytymisest�� Nord Poolissa ja muodostettu ty��kalu suuntaa-antavien todenn��k��isyyksien selvitt��miseksi auttavat kaupan laatijaa p����t��ksenteossa. Lyhyen t��ht��imen s��hk��johdannaisten hy��dynt��minen teollisessa energianhallinnassa on periaatteessa mahdollista esitellyn prosessin avulla, vaikka t��ydellinen k��ytt����notto vaatisi viel�� joitakin j��rjestelyj��. Keskittym��ll�� tilanteisiin jotka ty��ss�� kuvatulla prosessilla ovat hoidettavissa, ty��ss�� m����ritellyll�� menettelyll�� on mahdollisuudet saavuttaa ep��edullisen hintakehityksen riskin v��heneminen ja parempi taloudellinen tulos teollisen energianhallinnan s��hk��kaupank��ynniss��.

Disturbance of wildlife by outdoor winter recreation: allostatic stress response and altered activity-energy budgets

Anthropogenic disturbance of wildlife is of growing conservation concern, but we lack comprehensive approaches of its multiple negative effects. We investigated several effects of disturbance by winter outdoor sports on free-ranging alpine Black Grouse by simultaneously measuring their physiological and behavioral responses. We experimentally flushed radio-tagged Black Grouse from their snow burrows, once a day, during several successive days, and quantified their stress hormone levels (corticosterone metabolites in feces [FCM] collected from individual snow burrows). We also measured feeding time allocation (activity budgets reconstructed from radio-emitted signals) in response to anthropogenic disturbance. Finally, we estimated the related extra energy expenditure that may be incurred: based on activity budgets, energy expenditure was modeled from measures of metabolism obtained from captive birds subjected to different ambient temperatures. The pattern of FCM excretion indicated the existence of a funneling effect as predicted by the allostatic theory of stress: initial stress hormone concentrations showed a wide inter-individual variation, which decreased during experimental flushing. Individuals with low initial pre-flushing FCM values augmented their concentration, while individuals with high initial FCM values lowered it. Experimental disturbance resulted in an extension of feeding duration during the following evening foraging bout, confirming the prediction that Black Grouse must compensate for the extra energy expenditure elicited by human disturbance. Birds with low initial baseline FCM concentrations were those that spent more time foraging. These FCM excretion and foraging patterns suggest that birds with high initial FCM concentrations might have been experiencing a situation of allostatic overload. The energetic model provides quantitative estimates of extra energy expenditure. A longer exposure to ambient temperatures outside the shelter of snow burrows, following disturbance, could increase the daily energy expenditure by >10%, depending principally on ambient temperature and duration of exposure. This study confirms the predictions of allostatic theory and, to the best of our knowledge, constitutes the first demonstration of a funneling effect. It further establishes that winter recreation activities incur costly allostatic behavioral and energetic adjustments, which call for the creation of winter refuge areas together with the implementation of visitor-steering measures for sensitive wildlife.

Radio Imaging of the Very-High-Energy ��-Ray Emission Region in the Central Engine of a Radio Galaxy

The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 1012 electron volts and are bright sources of very-high-energy (VHE) ��-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE ��-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.

Risk Management Services in Energy Production

Ty�� k��sittelee energian tuotannossa esiintyvi�� t��rkeimpi�� taloudellisia ja teknisi�� riskej�� sek�� niiden hallitsemista energian tuottajan n��k��kulmasta. Ensiksi k��sitell����n yleisesti riskienhallintaa, eri riskityyppej�� ja esitet����n periaatteellinen riskienhallintaprosessi. Sen j��lkeen tarkastellaan energiamarkkinoiden nykytilannetta l��hinn�� Pohjoismaiden tasolla ja verrataan sit�� aikaisempaan tilanteeseen energian tuottajan kannalta. T��m�� siksi, ett�� energiamarkkinoiden vapautuminen on muuttanut merkitt��v��sti energian tuotantoon liittyvi�� taloudellisia riskej��, k��yt��nn��ss�� lis��nnyt niit��. P����paino on energian tuotannossa esiintyvien olennaisten riskien tarkastelussa ja niiden hallitsemisessa. Ensin esitell����n ty��n kannalta olennaiset riskit ja tekij��t joista ne aiheutuvat. Jokainen riski ja sen aiheuttamat haitat liiketoiminnalle kuvataan lyhyesti. Sen j��lkeen kiinnitet����n huomiota asioihin, jotka ovat tyypillisi�� energian tuotannolle ja aiheuttavat samalla erikoisvaatimuksia riskienhallinnalle. Sitten k��yd����n l��pi sopivat riskienhallinnan menetelm��t, jotka ovat yleisesti k��yt��ss�� energian tuotannossa, aiemmin esitetyille olennaisille riskeille. Esitetyist�� riskienhallinta menetelmist�� useimpia ei ole kohdistettu millek����n yksitt��iselle riskille, vaan monia niist�� voidaan k��ytt���� useammankin riskin hallintaan.

The reform of the European Energy Tax Directive reform : effect on prices

[spa] Para hacer frente a los riesgos relacionados con la contaminaci��n atmosf��rica, es ampliamente aceptada la necesidad de instrumentos de pol��tica encaminados a reducir las emisiones. La intervenci��n tiene por objeto reducir las conductas contaminantes y incentivar una conducta m��s respetuosa y el uso de tecnolog��as m��s eficientes. La Uni��n Europea cuenta con dos importantes mecanismos econ��micos para el control de emisiones a escala europea: la directiva sobre los impuestos energ��ticos, un instrumento de fiscalidad ambiental aprobado en 2003 que afecta el precio de los productos energ��ticos, y el sistema de comercio de los derechos de emisiones, introducido en 2005, que afecta directamente a la cantidad de emisiones de CO2. En 2011, la Comisi��n Europea propuso una nueva versi��n de la directiva sobre los impuestos energ��ticos. El objetivo principal de la propuesta es aumentar la eficacia del instrumento a trav��s de una mayor presi��n fiscal sobre los productos energ��ticos y de coordinar este instrumento de fiscalidad medioambiental con el sistema de comercio de los derechos de emisiones, para establecer una se��al de precio de CO2 coherente para todos los sectores. Sin embargo, en mayo de 2012 el Parlamento Europeo bloque�� la propuesta de la nueva versi��n del impuesto, y el proceso de actualizaci��n se detuvo. La preocupaci��n principal parec��a ser el efecto de dicha propuesta en la competitividad, en particular para los sectores que ser��an los m��s afectados dado el uso intensivo de los productos energ��ticos, como el sector del transporte. El objetivo de este estudio es analizar el efecto que la reforma de la directiva sobre los impuestos energ��ticos podr��a tener sobre el nivel de precios, en particular en los pa��ses de la Uni��n Europea donde esta reforma implicar��a un aumento de los impuestos energ��ticos. Utilizando datos del proyecto ���World Input-Output Database���, la principal conclusi��n es que el nuevo sistema de impuestos energ��ticos tendr��a un impacto muy bajo sobre los precios. Por lo tanto, dado que los precios no ser��an fuertemente afectados por la reforma, no habr�� inconvenientes para la competitividad y implicaciones en t��rminos de distribuci��n, pero, por otro lado, este resultado tambi��n implica una baja capacidad de esta reforma para provocar cambios en el consumo y la producci��n hacia menos presiones ambientales.

Nuclear Symmetry Energy Probed by Neutron Skin Thickness of Nuclei

We describe a relation between the symmetry energy coefficients csym(��) of nuclear matter and asym(A) of finite nuclei that accommodates other correlations of nuclear properties with the low-density behavior of csym(��). Here, we take advantage of this relation to explore the prospects for constraining csym(��) of systematic measurements of neutron skin sizes across the mass table, using as example present data from antiprotonic atoms. The found constraints from neutron skins are in harmony with the recent determinations from reactions and giant resonances.

Profit at Risk as a Risk Management Tool in Deregulated Energy Markets

Euroopan energiamarkkinat ovat olleet viimeisen kymmenen vuoden aikana suurten muutosten alla. Markkinoiden kehitys on ollut huomattavaa my��s Iso-Britanniassa, jossa s��hk��- ja kaasumarkkinat ovat olleet avoinna kilpailulle jo muutamia vuosia. Ennen markkinoiden avautumista energiyhti��t pystyiv��t siirt��m����n kaikki riskit suoraan asiakkaan kannettaviksi. Markkinoiden avautumisen my��t�� lis����ntynyt kilpailu on kuitenkin pakottanut energiayhti��it�� ajanmukaistamaan n��kemyksi����n riskeist��. Riskitekij��t, joista ei aiemmin tarvinnut v��litt����, on nyt pystytt��v�� tunnistamaan ja hallitsemaan. T��m�� ty�� keskittyy hinta- ja volyymiriskien hallintaan. Rahoitusmarkkinoilla pitk����n k��ytettyj�� riskienhallintaty��kaluja on otettu k��ytt����n my��s energiamarkkinoilla. Energiamarkkinoiden piirteet poikkeavat kuitenkin rahoitusmarkkinoista, eik�� n��it�� ty��kaluja voida ottaa k��ytt����n muutoksitta. Silti, jopa muutosten j��lkeen rahoitusmarkkinoiden riskienhallitav��lineet aliarvioivat energiamarkkinoiden hinta- ja volyymiriskej��. T��ss�� yhteydess�� ty��ss�� esitet����n Profit at Risk, PaR. PaR on skenaariopohjainen riskienhallinnan ty��kalu, joka on kehitetty erityisesti energiamarkkinoille ja t��ten huomioi niiden erikoispiirteet. Ty��n rungon muodostavat energiamarkkinoiden k��ytt��ytyminen, hinta- ja volyymiriskitekij��t sek�� pohdinta miten hinta- ja volyymiriskeilt�� voidaan suojautua ja miten niit�� voidaan hallita. PaR-metodologiaa verrataan perinteisiin riskienhallintamenetelmiin ja ty��n tavoitteena on tuoda esiin ne tekij��t, joiden ansiosta PaR on sopivampi ty��kalu energiamarkkinoiden riskienhallintaan kuin perinteiset menetelm��t. K��yt��nn��n esimerkkin�� ty��ss�� toimii Fortum Energy plus���n PaR ���malli. Koska PaR on kehitetty erityisesti energiamarkkinoille, se huomioi t��ysin markkinoiden aiheuttamat hinta- ja volyymiriskit. K��yt��nn��n esimerkki kuitenkin osoittaa, ett�� PaR menetelm��st�� ei ole riskienhallinnallista hy��ty�� ellei ty��kalun k��ytt��j��ll�� ole t��ydellist�� tiet��myst�� niin energiamarkkinoista kuin markkinoiden muutoksiin vaikuttavien tekij��iden k��ytt��ytymisest��.