The study of the negative pion production in neutron-proton collisions at beam momenta below 1.8 GeV/c

A detailed investigation of the reaction np -> pp\pi^{-} has been carried out using the data obtained with the continuous neutron beam produced by charge exchange scattering of protons off a deuterium target. A partial wave event-by-event based maximum likelihood analysis was applied to determine contributions of different partial waves to the pion production process. The combined analysis of the np -> pp\pi^{-} and pp -> pp\pi^{0} data measured in the same energy region allows us to determine the contribution of isoscalar partial waves (I=0) in the momentum range from 1.1 up to 1.8 GeV/c. The decay of isoscalar partial waves into (^1S_0)_{pp}\pi$ channel provides a good tool for a determination of the pp S-wave scalar scattering length in the final state which was found to be a_{pp}=-7.5\pm 0.3 fm.Comment: 6 pages, 6 figure

Observation of strong final-state effects in pi+ production in pp collisions at 400 MeV

Differential cross sections of the reactions $pp \to d\pi^+$ and $pp \to pn\pi^+$ have been measured at $T_p = 400$ MeV by detecting the charged ejectiles in the angular range $4^0 \leq \Theta_{Lab} \leq 21^\circ$. The deduced total cross sections agree well with those published previously for neighbouring energies. The invariant mass spectra are observed to be strongly affected by $\Delta$ production and $NN$ final-state interaction. The data are well described by Monte Carlo simulations including both these effects. The ratio of $pp \to pn\pi^+$ and $pp \to d\pi^+$ cross sections also compares favourably to a recent theoretical prediction which suggests a dominance of $np$-production in the relative $^3S_1$-state.Comment: 17 pages, 5 figure

Dependence of pp->pp pi0 near Threshold on the Spin of the Colliding Nucleons

A polarized internal atomic hydrogen target and a stored, polarized beam are used to measure the spin-dependent total cross section Delta_sigma_T/sigma_tot, as well as the polar integrals of the spin correlation coefficient combination A_xx-A_yy, and the analyzing power A_y for pp-> pp pi0 at four bombarding energies between 325 and 400 MeV. This experiment is made possible by the use of a cooled beam in a storage ring. The polarization observables are used to study the contribution from individual partial waves.Comment: 6 pages, 1 table, 4 figures, corrected equations 2 and

Economía circular. Aplicación empresarial y modelos de negocio

[Resumen]: La Economía Circular es un modelo económico que propone una nueva forma de producir y consumir. Constituye una alternativa viable para hacer frente a la problemática medioambiental y lograr un desarrollo sostenible. Para ello, es necesario un compromiso y esfuerzo integrado de todos sus agentes: el Estado, las empresas y los consumidores. En el presente trabajo se pretende abarcar la dimensión institucional, examinando iniciativas promovidas por las entidades involucradas; y la dimensión empresarial, poniendo especial foco en la aplicación práctica del modelo. Como punto de partida, y para contextualizar la situación actual, se abordan las principales estrategias y planes de acción desarrolladas a nivel mundial, en la Unión Europea y España. Con el objetivo de hacer visible su importancia y magnitud en la agenda de las instituciones, se explican sus iniciativas más relevantes. En el eje de empresas, se describe cómo las compañías podrían llevar adelante la transformación circular. Analizando el contexto, profundizando en diversos modelos de negocio y sus aplicaciones reales, se obtiene como resultado una hoja de ruta circular. Si bien las empresas implementan sus principios de forma heterogénea, según las características propias de la organización, se pueden establecer cinco modelos de negocio: suministros circulares, recuperación de recursos, extensión de vida útil, producto como servicio y plataformas de uso compartido. Dentro de cada uno se mencionan diversas estrategias para concretar la circularidad a lo largo de toda la cadena de valor. A partir de este análisis se concluye que la Economía Circular tiene un carácter sistémico y requiere una marcada etapa de transición. El compromiso de todos sus agentes permitirá avanzar progresivamente hacia un grado de circularidad mayor.[Abstract]: Circular Economy is an economic model that proposes a new way of producing and consuming. It is a viable alternative to tackle environmental issues and to achieve sustainable development. This requires an integrated commitment and effort from all its stakeholders: the State, companies, and consumers. This paper aims to cover the institutional dimension, examining initiatives promoted by the entities involved and the business dimension, emphasizing on the implementation of the model. As a starting point, and to contextualize the current situation, the main strategies and action plans developed globally in the European Union and Spain are addressed. The most relevant initiatives are explained to highlight their importance and magnitude in the agenda of the institutions. In the business axis, it is described how companies could carry out the circular transformation. By analyzing the context, delving into different business models and their actual applications, a circular roadmap is obtained as a result. Although companies implement their principles in heterogeneous ways, depending on the organization’s own characteristics, five business models can be established: circular sourcing, resource recovery, lifecycle extension, product-as-a-service and shared-use platforms. Within each of these models, various strategies are mentioned to implement circularity along the entire value chain. From this analysis, it is concluded that the Circular Economy has a systemic character and requires a significant transition phase. The commitment of all its stakeholders will allow progressively to move towards a higher degree of circularity.Traballo fin de mestrado (UDC.ECO). Dirección e administración de empresas. Curso 2022/202

Close-to-threshold Meson Production in Hadronic Interactions

Studies of meson production at threshold in the hadron--hadron interaction began in the fifties when sufficient energies of accelerated protons were available. A strong interdependence between developments in accelerator physics, detector performance and theoretical understanding led to a unique vivid field of physics. Early experiments performed with bubble chambers revealed already typical ingredients of threshold studies, which were superseded by more complete meson production investigations at the nucleon beam facilities TRIUMF, LAMPF, PSI, LEAR and SATURNE. Currently, with the advent of the new cooler rings as IUCF, CELSIUS and COSY the field is entering a new domain of precision and the next step of further progress. The analysis of this new data in the short range limit permits a more fundamental consideration and a quantitative comparison of the production processes for different mesons in the few--body final states. The interpretation of the data take advantage of the fact that production reactions close-to-threshold are characterized by only a few degrees of freedom between a well defined combination of initial and exit channels. Deviations from predictions of phase-space controlled one-meson-exchange models are indications of new and exciting physics. Precision data on differential cross sections, isospin and spin observables -- partly but by no means adequately available -- are presently turning up on the horizon. There is work for the next years and excitement of the physics expected. Here we try to give a brief and at the same time comprehensive overview of this field of hadronic threshold production studies.Comment: 100 pages, Review article to be published in Prog. Part. Nucl. Phys. Vol. 49, issue 1 (2002

TOPAS 2 - ein hochaufloesendes Taggingsystem am Bonner SAPHIR-Detektor

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

a qualitative study

Die Ergebnisse einer randomisierten kontrollierten Studie (RCT) bei älteren Patienten mit chronischen Nackenschmerzen zeigten weder auf der Visuellen Analogskala noch auf der Neck, Pain and Disability Scale eine Verbesserung der Nackenschmerzen durch Qigong und physiotherapeutische Nackenübungen im Vergleich zu keiner Behandlung (Wartelistengruppe). Da ein größerer Teil der Patienten die Therapien nach Beendigung der Interventionen auf eigene Kosten fortführte, ergab sich ein Widerspruch zu den Ergebnissen. Die hier vorliegende qualitative Studie hatte zum Ziel, mögliche Effekte von Qigong und Nackenübungen und das Erleben des Trainings aus der individuellen Sicht der Studienteilnehmer zu evaluieren. Hierzu wurden die Teilnehmer der Qigonggruppe und der physiotherapeutischen Nackenübungsgruppe aus der RCT getrennt voneinander gerankt und in der Reihenfolge kontaktiert. Mit den ersten zehn Patienten, die in beiden Gruppen zustimmten, wurden semistrukturierte, problemzentrierte Einzelinterviews durchgeführt. Im Anschluss an die Datenerhebung wurde das Tonmaterial transkribiert und unter Verwendung der Software Atlas/ti® unter Anwendung der strukturierten Inhaltsanalyse nach Mayring analysiert. Die zu 100% weibliche Studienpopulation für die qualitative Studie war im Mittel 76,2 (±4,52) Jahre alt. Die Interviewdauer betrug durchschnittlich 37 Minuten (±12,14 min). Die Gruppen unterschieden sich deutlich hinsichtlich des berichteten zentralen Effekts der Therapien. In der Gruppe der physiotherapeutischen Nackenübungen sahen die Patientinnen das Üben als sinnvoll für den Erhalt ihrer Selbstständigkeit an und schätzten die Möglichkeit, aktiv gegen den altersbedingten, körperlichen Abbau vorgehen zu können. Für die Qigongteilnehmerinnen stellte die Möglichkeit, sich durch die Therapie entspannen zu können, den zentralen Gewinn dar. Von einem anfangs teils eher skeptischen Blickwinkel wechselte ihre Einstellung gegenüber der Qigongtherapie zu einer positiven Haltung und sie äußerten, dass die unerwartete Neuentdeckung eine Bereicherung in ihrem Alltag darstellte. Außerdem wurden in der Qigonggruppe positive vegetative Effekte erläutert, die oft in Schwachstellen der individuellen Gesundheit auftraten. Im Weiteren berichteten beide Gruppen von einer leichten bis mittleren Reduktion ihrer Beschwerden, jedoch von keiner Heilung. Berichte über die Schmerzreduktion wurden häufig von Äußerungen zu einer verbesserten Beweglichkeit begleitet. Gruppe und Lehrerin stellten in beiden Therapiegruppen wichtige Motivationsfaktoren für das regelmäßige und exakte Trainieren dar. Zusammenfassend lässt sich sagen, dass für Teilnehmerinnen der physiotherapeutischen Nackenübungen der Erhalt der Selbstständigkeit, für Patientinnen des Qigong die Möglichkeit, durch die Therapie zu entspannen, den zentralen therapeutischen Nutzen darstellte. Beide Gruppen berichteten von einer Reduktion der Schmerzen, welche für sie jedoch nicht zentral für das Weiterführen der Therapie war.The aim of this qualitative study was to evaluate the effects of qigong and exercise therapy on chronic neck pain from the perspective of elderly patients. To achieve this aim, participants from the Qigong group and the exercise group from a previously performed RCT were contacted. We performed semi-structured, problem-centered interviews with ten patients from both groups. After the data collection, the material was transcribed and analyzed according to the structured content analysis of Mayring, using the software Atlas / ti The study population was 100% female, with an average age of 76.2 (ą 4.52) years. The interviews had an average length of 37 minutes (ą 12.14 min). There was a clear difference between the main effect reported in the Qigong group and the main effect reported in the exercise therapy. For participants of the exercise group, the main benefit was the preservation of their self-independence in an older age. The clear benefit for patients of the Qigong group was the ability of deep relaxation during the training. Both groups reported a reduction of pain, however, this was not the main reason for them to continue the therapy