Bayesowskie uśrednianie klasycznych oszacowań w prognozowaniu wskaźników makroekonomicznych z użyciem danych z testów koniunktury

This paper presents another version of model designed to forecast main macroeconomic indicators with the use of economic survey data. In previous papers (Białowolski, Kuszewski, Witkowski, 2010a, 2010b, 2011, 2012a, 2012b) methods for developing models used for forecasting GDP growth rate, unemployment rate and CPI were proposed. The set of regressors in those models included only lagged dependent variables and indices based on various survey data. In this paper the specification of the forecasting model is selected with the use of Bayesian averaging of classical estimates (BACE). This algorithm enables an automatic process of selection of functional form of the model. Next the influence of deterministic and stochastic seasonality in time series on forecasting process is concerned. An intuitive procedure of applying and selecting among both types of seasonality in the forecasting process is discussed. Afterwards their forecasting capabilities are considered. (original abstract)W niniejszej pracy przedstawiono kolejną wersję modelu dla prognozowania podstawowych wskaźników makroekonomicznych z wykorzystaniem danych z testów koniunktury. W pracach Białowolskiego, Kuszewskiego i Witkowskiego (2010a, 2010b, 2011, 2012a, 2012b) rozwijano metodykę budowy modeli dla prognozowania tempa zmian produktu krajowego brutto, stopy bezrobocia i wskaźnika cen towarów konsumpcyjnych. W zbiorze regresorów tych modeli, oprócz opóźnionych w czasie zmiennych endogenicznych, uwzględnia się wyłącznie wyniki różnych testów koniunktury. Badanie dotyczy specyfikacji modelu prognostycznego metodą bayesowskiego uśredniania klasycznych oszacowań (Bayesian averaging of classical estimates, BACE). Przyjęte rozwiązanie umożliwia automatyzację proces doboru postaci modelu. W kolejnym etapie postępowania jest rozważany wpływ sezonowości deterministycznej i stochastycznej szeregów czasowych na wynik procesu prognozowania. Zaproponowano intuicyjną procedurę uwzględniania obu rodzajów sezonowości w procesie prognozowania. Po zakończeniu procesu estymacji i doboru modeli weryfikowano ich możliwości prognostyczne. (abstrakt oryginalny

Radiotherapy treatment planning for breast cancer patients after a subcutaneous mastectomy with the use of a prosthesis or expander

Introduction. Medical physicists planning radiation treatment are increasingly confronted with situations that require special attention. Undoubtedly, one such situation is the postoperative irradiation of a patient with breast cancer in which there is a prosthesis or an expander. In recent years, expanders have appeared in this location, which, due to the density of the device’s valve makes it difficult to prepare an acceptable treatment plan. The study aims to present treatment planning in these situation in various Polish cancer centres and to compare overall patient preparation for the treatment. Material and methods. A questionnaire was prepared and sent to more than 20 radiotherapy departments, which included basic questions regarding the preparation of an irradiation plan for patients treated for breast cancer after a subcutaneous mastectomy with immediate reconstruction with a prosthesis or expander. The survey encompassed eight radiotherapy departments. Results. Not all radiotherapy departments require a manufacturer’s certificate, which shows that the manufacturer does not prohibit the use of a prosthesis/expander during treatment with ionizing radiation. The X 6MV photons and the supine position, total and fraction doses: from 40 to 60 Gy and from 2 to 2.67 Gy, respectively, are the most commonly used. The way of defining them also depends on the oncological centre. The most commonly used irradiation technique is VMAT. Conclusion. The conclusion from the questionnaire – no standardisation of treatment planning – should encourage the community, at least medical physicists, to develop rules of conduct in this case. Irradiation techniques are mainly dynamic ones. The expander or prosthesis does not significantly affect the dose distributions

Neointima development in externally stented saphenous vein grafts

Introduction : The main limitation of coronary artery bypass grafting (CABG) is rapid neointimal hyperplasia leading to graft failure. Aim : To assess plaque formation in saphenous vein grafts (SVG) covered by an external Dacron stent in comparison with the classical technique. Material and methods : In the study group vein grafts covered by external stent mesh made of Dacron were implanted. An intravascular ultrasonography (IVUS) study was performed in 35 aorto-coronary SVG covered by an external Dacron stent and in 64 normal SVG during the first year after CABG. In each SVG 25 mm of good quality IVUS image, volumes of lumen, plaque (neointima), outer border of the vein graft (external SVG) and adventitia were calculated in three time periods: 0–130 days, 130–260 days and 260–390 days. Results : Between the first and second time period, lumen volume (mm3) was reduced from 10.33 ±4.4, to 6.80 ±2.23 in the second period and 5.69 ±1.26 in the third one. This effect was much less marked in normal grafts. The corresponding lumen volume (mm3) was: 10.90 ±3.9, 9.15 ±2.94 and 8.92 ±2.93 in consecutive time periods. Plaque volume (mm3) did not change in control grafts during the course of the study, but it increased very significantly in stented grafts from 0.86 ±1.24 in the first period to 2.70 ±1.58 in the second and 3.29 ±2.66 in the third one. Conclusions : The experimental technique of implanting SVG covered with an external elastic Dacron stent seems to be inferior to traditional ones. This is probably due to the more complicated process of vein implantation and higher micro-injury occurrence during the surgery

Détection optique de la dynamique magnéto-acoustique

In the developing field of spin wave-based information technology, this work investigates the possibility to use surface acoustic waves (SAW) to excite spin-waves in ferromagnetic thin layers relying on the magnetoelastic coupling. This would provide a non-inductive, efficient, and remote addressing of spin waves. In the first project we develop an experimental setup to generate electrically excited SAWs phase-locked to probe laser pulses. The magnetization dynamics is detected by an optical bridge using magneto-optical effects (Kerr and Voigt). We investigate the resonant magneto-elastic coupling in a thin film of the ferromagnetic semiconductor (Ga,Mn)As. To reach resonant coupling, the spin-wave frequency is scanned across the SAW frequency using a magnetic field. We disentangle the photoelastic contribution from the magneto-optical one, from which we obtain the amplitude of magnetization precession. We show that it is driven solely by the acoustic wave. Its field dependence is shown to agree well with theoretical calculations. Its amplitude resonates at the same field as the resonant attenuation of the acoustic wave, clearly evidencing the magnetoacoustic resonance with high sensitivity. The influence of temperature, SAW frequency and power on the coupling efficiency are studied. In the second project we use SAWs thermoelastically excited by a tightly focused laser beam on ferromagnetic metals (Ni, FeGa, Co) on a transparent substrate (glass, sapphire). Spatio-temporal maps of the surface displacement and magneto-optical signal are obtained. A high-frequency shift of the frequency spectrum of the latter gives a hint for spin-wave excitation by SAWs.Ce travail se situe dans le contexte de l’utilisation des ondes de spin comme vecteur d’information. Il explore la possibilité d’exciter l’aimantation dans de fines couches ferromagnétiques grâce au couplage magnéto-élastique. Cela permettrait un adressage non-inductif, efficace, et distant des ondes de spin. Dans un premier volet, nous avons développé un dispositif expérimental générant des ondes acoustiques de surface (ODS) électriquement, verrouillées en phase à des impulsions de laser sonde. La dynamique d’aimantation est détectée grâce aux effets magnéto-optiques (Kerr et Voigt). Nous étudions le couplage magnétoélastique résonant dans une couche mince du semiconducteur magnétique (Ga,Mn)As. Afin d’atteindre la résonance, la fréquence des ondes de spin est ajustée à celle des ODS par un champ magnétique. Nous isolons les contributions photo-élastique et magnéto-optique du signal, pour quantifier l’amplitude de la précession d’aimantation. Nous montrons que la précession observée est exclusivement déclenchée par l’ODS. La variation en champ de son amplitude correspond très bien à celle calculée, et elle est maximum au champ pour laquelle l’absorption de l’ODS est maximale, démontrant clairement la résonance magnétoacoustique. L’influence de la fréquence et de la puissance de l’ODS, ainsi que de la température sur l’efficacité du couplage est également explorée. Dans un deuxième volet, nous avons excité des ODS par effet thermoélastique grâce à un faisceau laser focalisé, et cela sur des couches magnétiques métalliques cette fois-ci (Ni, FeGa, Co), déposées sur un substrat transparent (verre, sapphire). Des cartes spatio-temporelles du déplacement de la surface et du signal magnéto-optique ont été obtenues. Un décalage du spectre magnéto-optique vers les hautes fréquences semble indiquer une excitation des ondes de spin par les ODS

Bayesian Averaging of Classical Estimates in Forecasting Macroeconomic Indicators with Using Business Survey Data

W niniejszej pracy przedstawiono kolejną wersję modelu dla prognozowania podstawowych wskaźników makroekonomicznych z wykorzystaniem danych z testów koniunktury. W pracach Białowolskiego, Kuszewskiego i Witkowskiego (2010a, 2010b, 2011, 2012a, 2012b) rozwijano metodykę budowy modeli dla prognozowania tempa zmian produktu krajowego brutto, stopy bezrobocia i wskaźnika cen towarów konsumpcyjnych. W zbiorze regresorów tych modeli, oprócz opóźnionych w czasie zmiennych endogenicznych, uwzględnia się wyłącznie wyniki różnych testów koniunktury. Badanie dotyczy specyfikacji modelu prognostycznego metodą bayesowskiego uśredniania klasycznych oszacowań (Bayesian averaging of classical estimates, BACE). Przyjęte rozwiązanie umożliwia automatyzację proces doboru postaci modelu. W kolejnym etapie postępowania jest rozważany wpływ sezonowości deterministycznej i stochastycznej szeregów czasowych na wynik procesu prognozowania. Zaproponowano intuicyjną procedurę uwzględniania obu rodzajów sezonowości w procesie prognozowania. Po zakończeniu procesu estymacji i doboru modeli weryfikowano ich możliwości prognostyczne.This paper presents another version of model designed to forecast main macroeconomic indicators with the use of economic survey data. In previous papers (Białowolski, Kuszewski, Witkowski, 2010a, 2010b, 2011, 2012a, 2012b) methods for developing models used for forecasting GDP growth rate, unemployment rate and CPI were proposed. The set of regressors in those models included only lagged dependent variables and indices based on various survey data. In this paper the specification of the forecasting model is selected with the use of Bayesian averaging of classical estimates (BACE). This algorithm enables an automatic process of selection of functional form of the model. Next the influence of deterministic and stochastic seasonality in time series on forecasting process is concerned. An intuitive procedure of applying and selecting among both types of seasonality in the forecasting process is discussed. Afterwards their forecasting capabilities are considered