Cíl: Porovnání radiační zátěže a obrazové kvality při HRCT plic mezi třemi přístroji v jedné nemocnici. Metodika: Retrospektivně bylo zhodnoceno 3 x 50 náhodně vybraných pacientů, kteří podstoupili HRCT plic na třech různých přístrojích (Somatom Definition AS [SD], Somatom Emotion [SE], Brilliance iCT [iCT]) v rámci jedné nemocnice. Rekonstrukce byly provedeny standardně s použitím měkkotkáňového (mediastinálního) algoritmu a algoritmu s vysokým prostorovým rozlišením (HRCT). Obrazová kvalita byla měřena jako směrodatná odchylka denzity v trachee, levé síni, aortě a hodnocena na čtyřstupňové Likertově škále. Podle naměřených hodnot efektivního průměru pacientů byl vytvořen fantom, který byl zobrazen s pěti úrovněmi proudu na rentgence. Výsledky: Obrazová kvalita vyjádřená jako směrodatná odchylka denzity v zájmové oblasti byla v mediastinální rekonstrukci významně lepší u přístroje SD oproti SE (p = 0,0060), rozdíl v subjektivním hodnocení na čtyřstupňové škále významný nebyl (p = 0,11). V HRCT rekonstrukci byla směrodatná odchylka denzity významně nižší u přístroje iCT oproti SD (p = 0,0003), avšak obrazová kvalita byla subjektivně hodnocena o třetinu stupně hůře (p = 0,028). Průměrná radiační zátěž z vyšetření byla na přístroji SD 2,6násobná a na SE l,9násobná v porovnání siCT(p< 0,0001). Závěr: V práci jsme ukázali významný rozdíl v radiační zátěži při HRCT vyšetření plic na různých přístrojích v jedné nemocnici. Mezi přístroji s největším rozdílem byl minimální rozdíl v subjektivním hodnocení obrazové kvality HRCT, což je nejspíše dáno optimalizací vyšetření a zvyklostmi., Aim: To compare radiation dose and image quality in HRCT of the lung among three scanners in a single institution. Methods: HRCTs of the lung of fifty randomly selected patients per scanner in a single institution (Somatom Definition AS [SD], Somatom Emotion [SE], Brilliance iCT [iCT]) were evaluated. Reconstructions were performed with a standard soft-tissue (mediastinal) and high-resolution (HRCT) reconstruction algorithms. The image quality was measured as a standard deviation of the density in the trachea, left atrium, and aorta and evaluated on a four-point Likert scale. A phantom, that was constructed according to the real patient data, was scanned with five different levels of the tube current. Results: In the soft-tissue reconstruction, the image quality expressed as standard deviation of density was significantly better in the SD compared to SE (p = 0.0060) and there was no difference in subjective ratings of the image quality (p = 0.11). In HRCT reconstruction, the image quality was significantly better in iCT compared to SD (p = 0.0003) but the ratings were worse by a third of a point (p = 0.028). The average radiation dose estimate was 2.6 times (SD) and 1.9 times (SE) higher compared to iCT (p < 0.0001). Conclusion: A significant difference in radiation dose estimate in HRCT of the lung among three different scanners was demonstrated. Between the two scanners with the highest and the lowest radiation dose, only a minimal difference in subjective evaluation of image quality was found, which is probably due to optimization and established practice., Lukáš Lambert, Lucie Šimáková, Alena Lambertová, Patrik Matras, JiříVotruba, Josef Hořejš, and Literatura
Mine roadways developed in highly stressed strata are subject to roof shear, which under severe conditions may manifest as the well known symptom of guttering, particularly at the roadway edge leading into the major horizontal stress. This roof shear can progressively reduce the effectiveness of bolt confinement of the strata within the lower roof horizon affecting stability of the immediate roof. This paper presents the results of a study to investigate the effectiveness of polymers as skin reinforcement in highly stressed coal mine roadways, as they may provide better roadway skin support than the currently used steel mesh. A large concrete block intercepted with artificial joints and reinforced with steel bolts without skin support, was loaded until significant slip occurred along the joints. Upon loading, a roof cavity resembling a gutter developed, as some of the jointed concrete parted from the free surface. In addition to bolts, subsequent models with identical fracture planes were supported with steel mesh or with glass reinforced polymer skin bonded to the free side. Loads and displacements were compared for models with and without skin reinforcement. As expected the skin support helped resist gutter formation, to various degrees, while increasing the residual strength of the concrete block. It was found that there was significantly less bedding displacements in models with the polymer skin, when compared with both steel mesh and no skin reinforcement. This suggests that there would be benefits to using a spray on polymeric skin as surface support in roofs subject to severe roof shear., Jan Nemcik, Ernest Baafi and Ian Porter., and Obsahuje bibliografii
This paper examines the social origins of the members of the Premonstratensian Canonry at Strahov, Prague, in the last quarter of the 18th and the second quarter of the 19th centuries. In the introduction we outline changes in the composition of the community in the period under discussion (a decline in the number of canons in the late 18th C and its causes; changes in their activities both within the order and in the public sphere). The main focus of the study is two surveys into the social origins of individual Premonstratensians covering the intake of novices in the periods 1750-1763 and 1804-1816, in which we assume they would attain the peak of their monastic career after 20-25 years spent with the order. Our main source was the confirmation of baptism of individual candidates, records of which for the years in question are relatively intact in the Strahov archive; these were supplemented by research in the relevant registries. An analysis of the data showed that the majority of novices at Strahov monastery were young men with an urban background, whereby there is a clearly perceptible shift from the elite urban classes in the first sample to more artisan circles, as well as a higher proportion of privileged boys from small provincial towns, in the second. Surprisingly, in the early years of the 19th century we no longer find the sons of officials employed in patrimonial (i.e. estate) administration. However, a broader chronological sample would be necessary to confirm that this was indeed a long‐term trend. Neither was it confirmed that more young men of rural origin were interested in joining a monastery, as we had assumed, not even those from the Strahov estates. This shift was not to happen till far later in the century., Hedvika Kuchařová., and Obsahuje bibliografické odkazy
In our study we find, from the analysis of VLBI observations, small quasi-periodic fluctuations of the period and quality factor of retrograde Free Core Nutation (FCN), ranging mainly between 429.8 to 430.8 days and 17000 to 21000, respectively. To this end, we use resonant effects in several dominant forced nutation terms to calculate the period and quality factor of FCN in running 6-year intervals. We also recently demonstrated that the atmospheric and oceanic excitations are capable of exciting FCN. Both amplitude and phase of the geophysically excited motion are consistent with the values observed by VLBI, in the interval of tens of years. The geophysical excitations are now numerically integrated, using Brzeziński’s broadband Liouville equations, and removed from the observed celestial pole offsets. The remaining part is then used to derive the period and quality factor of FCN in running intervals, and to study the temporal stability of these important Earth parameters. It is demonstrated that the observed quasi-periodic variations of both parameters are probably not caused by these geophysical excitations., Jan Vondrák and Cyril Ron., and Obsahuje bibliografii
V astronomické a fyzikální komunitě panuje všeobecné přesvědčení, že dodatečně relativistické stáčení perihelia dráhy Merkuru 43" za století je již dávno a mnohokrát prověřená hodnota, na které není třeba nic měnit. Že je dána rozdílem pozorovaného stáčení perihelia Merkuru a počítaného stáčení pomocí Newtonovy mechaniky. V tomto případě se ale odečítají dvě skoro stejně velká čísla, která jsou navíc zatížena mnoha chybami. Výsledný rozdíl 43" za století je tak nejistý a nemusí odpovídat skutečnosti., The perihelion shift of Mercury's orbit is thought to be one of the fundamental tests of the validity of the general theory of relativity. In the current (astro)physical community, it is generally accepted that the additional relativistic perihelion shift of Mercury is the difference between its observed perihelion shift and the one predicted by Newtonian mechanics, and that this difference equals 43" per century. However, as it results from the subtraction of two quite inexact numbers of almost equal magnitude, it may be subject to cancelation errors. As such, the above accepted value is highly uncertain and may not correspond to reality., Michal Křížek., and Obsahuje seznam literatury
Cíl: Analýza systému speciální ošetřovatelské péče na intervenčních pracovištích v ČR se zaměřením na dekanylaci arteriálního sheathu. Metodika: Pro sběr empirických údajů jsme použili metodu námi vytvořeného dotazníku jen pro účely této práce. Dotazník obsahoval sedm otázek (šest uzavřených, dichotomických, jedna otevřená). Oslovená pracoviště byla vybrána dle oficiálního seznamu Národního registru kardiovaskulárních intervencí (NRKI) ČR, kde je uvedeno 22 pracovišť provádějících kardiovaskulární intervence. Dotazník byl distribuován cestou oficiálních mailových adres. Výsledky byly zpracovány pro jednotlivé sledované položky do tabulky s určením absolutní četnosti. Výsledky: Z analyzovaných výsledků vyplývá, že se v ČR více uplatňuje přístup přes arteria radialis, až v 78 %. Dekanylaci sheathu z arteriálního povodí provádějí sestry na 16 pracovištích, přičemž zavedený standard má jen 10 pracovišť. Proškolení sester pro odborný výkon probíhá jen na čtyřech pracovištích, což je v nepoměru k množství dekanylací prováděných sestrou. Závěr: Zavedení ošetřovatelského standardu pro dekanylaci sheathu není na pracovištích v ČR podmínkou pro to, aby sestra mohla tento výkon provádět, přestože jej na 16 pracovištích provádí zcela rutinně. Dle získaných dat je management dekanylace shethu v rámci ČR velmi nejednotný., Aim: The analysis of special nursing care focusing on arterial sheath removal at interventional sites in the Czech Republic. Methods: The empirical data was collected by means of a questionnaire created by us for the purposes of this article. The questionnaire consisted of seven questions (six closed, dichotomous; one open). According to the National Register of Cardiovascular Interventions (NRKI) of the Czech Republic, there are 22 centres performing cardiovascular interventions. All of them were approached with a request to fill in the questionnaire. The questionnaire was distributed through official e‑mail addresses. The results for each monitored item were put into a chart showing absolute frequency. Results: The analysis showed that the most common approach in the Czech Republic is via radial artery, in up to 78% of cases. Sheath decannulation from the arterial basin is performed by nurses at 16 centres, 10 of which have implemented the specialised nursing standard. Nurse training for professional performance takes place at four centres only, which is disproportionate to the number of decannulations carried out by nurses. Conclusion: The introduction of the nursing standard for sheath removal is not a condition for a nurse to perform it, despite the fact that it is carried out quite routinely at 16 centres. According to the data obtained, the management of sheath decannulation in the Czech Republic is very disunited., and Klemsová L., Žiaková K.