The aim of this study was to assess the performance of several approximation techniques for ionospheric total electron content (TEC) mapping. Approximation techniques based on data-fitting with local or general two-dimensional polynomials, local planes or distance-dependent interpolation were applied and tested. For the ionosphere modeling, dual-frequency GPS data from Polish GBAS system (ASG-EUPOS) were used, and TEC was estimated together with hardware delays from phasesmoothed pseudoranges. Next, grids of vertical TEC values with spatial resolution of 0.25 degrees in both latitude and longitude were generated using the evaluated approximation techniques. Subsequently the grids were used to create regional TEC maps with 5-minute temporal resolution, and also to create ionospheric delay corrections for GPS positioning. The quality of the resulting ionospheric maps was tested twofold, firstly by comparison to high-quality CODE global ionosphere maps (GIM), which were generated using data from about 150 GPS sites of the International GNSS Service (IGS). Secondly, by creating double-differenced ionospheric delay corrections and comparing them to reference values derived from the reference network data processing. For the correction tests, two perpendicular baselines directed North-South (N-S) and West-East (W-E) and reaching up to 100 km were selected. The approximation methods were analyzed with a special emphasis on the diverse ionospheric conditions. For the testing, a quiet ionosphere day of 20 March 2012 and an active ionosphere day of 9 March 2012 were selected. The results show that the regional models properly represent the changing ionosphere, with the best results provided by data-fitting into local functions., Anna Krypiak-Gregorczyk, Pawel Wielgosz, Dariusz Gosciewski and Jacek Paziewski., and Obsahuje bibliografii
Príspevok sa zaoberá analýzou konceptu validity a hľadaním dôvodov absencie konsenzu v jej definovaní a vnímaní. Najvýznamnejšie koncepcie validity sú konfrontované z diachronického hľadiska s dôrazom na konceptuálne a epistemologické otázky. Táto analýza naznačuje, že rozdiely medzi jednotlivými koncepciami validity nie sú terminologickými hrami, ale majú vecné dôsledky. Zároveň je demonštrované, že význam aj tej najužšej a najčastejšie uvádzanej definície (test je validný, ak meria to, čo má merať) závisí na niekoľkých voľbách, ktoré sú v zásade arbitrárne. Tie následne implikujú empirické postupy potrebné pre atribúciu prívlastku „validný“ a v konečnom dôsledku aj to, či by mala byť validita považovaná za relačný alebo kauzálny koncept., The article discusses the concept of validity and explores the reasons for the absence of a widespread consensus in its definition and perception. Applying a diachronic perspective, the most influential conceptions of validity are being confronted with an emphasis on both conceptual and epistemological issues. Based on that analysis, it is argued that differences between several conceptions of validity are not just a terminological quibble. Furthermore, it is demonstrated that the meaning of even the simplest and mostly cited definition (a test is valid if it measures what it purports to measure) depends on some choices that are in fact arbitrary. These choices made further imply the epistemological procedures needed for the attribution of the "validity" label and whether validity should be considered a relational or a causal concept., Ivan Ropovik., and Obsahuje seznam literatury
Úvod: Test 16 slov (T16S) (v originálu Enhanced Cued Recall Test) je skríningový test k diagnostice poruch paměti ve stáří. T16S využívá kategorickou nápovědu během kontrolovaného učení a vybavení. Předpokládá se, že testy vycházející z tohoto paradigmatu jsou schopny identifikovat tzv. hipokampální poruchu paměti, která je charakterizována nízkým skóre ve volném vybavení s minimálním efektem nápovědy a je typická pro Alzheimerovu demenci (AD), a odlišit ji od poruchy paměti frontálního typu, kdy například pacienti s behaviorální variantou frontotemporální demence (bvFTD) navzdory nízkému volnému vybavení relativně profitují z nápovědy. <p align="">Cíl: Ověřit rozlišovací schopnost a využitelnost T16S v diferenciální diagnostice poruch paměti u pacientů s AD a s bvFTD. Metodika: Třicet šest pacientů s diagnózou pravděpodobné AD ve stadiu lehké demence (MMSE 21,7 ? 2,4), 15 pacientů s pravděpodobnou bvFTD (MMSE 23,8 ? 2,4) a 45 kognitivně zdravých seniorů (KS) (MMSE 28,96 ? 1,17) bylo vyšetřeno klinicky, absolvovali komplexní vyšetření neuropsychologickou baterií včetně T16S. <p align="">Výsledky: Skupiny se lišily ve všech třech ověřovaných skórech T16S: ve volném a celkovém vybavení i ve využití nápovědy (p < 0,001). Pro odlišení obou demencí od norem je vhodné zejména skóre volného vybavení (senzitivita a specificita 94 % a 100 % pro AD a 80 % a 91 % pro bvFTD), pro diferenciální diagnostiku obou demencí je nejlepším indexem skór celkového vybavení (senzitivita 86 % a specificita 87 %). <p align="">Závěr: Test paměti T16S je senzitivní a specifický test pro diagnostiku specifické poruchy paměti u AD a bvFTD. Může přispět k diferenciální diagnostice a jako takový ho doporučujeme k praktickému použití v klinické praxi., Introduction: Enhanced Cued Recall (ECR) memory test is especially valuable in screening for cognitive impairment in the elderly. ECR uses categorical cues during controlled encoding and recall; tests based on this paradigm are considered to be able to identify hippocampal memory impairment characterized by poor free recall with minimal effect of cueing, typical of Alzheimer’s disease (AD). The test could aid in differentiating memory impairment in behavioural variant frontotemporal dementia (bvFTD) versus AD – despite the poor free recall bvFTD patients benefit considerably from cueing. <p align="">Objective: To establish the validity of ECR in diagnosing memory impairment in AD and bvFTD. Methods: Thirty six patients with probable mild AD (MMSE 21.7 ? 2.4), 15 with probable bvFTD (MMSE 23.8 ? 2.4) and 45 healthy elderly (HE) (MMSE 28.96 ? 1.17) underwent clinical and neuropsychological examination including ECR. <p align="">Results: There was a statistically significant difference between all groups in all three ECR memory performance scores: free recall, total recall and cueing effect (p < 0.001). Free recall was the most effective score for discriminating dementias from healthy elderly (sensitivity 94% and specificity 100% for AD and sensitivity 80% and specificity 91% for bvFTD); total recall was most effective for differential diagnosis of both dementias (sensitivity 86% and specificity 87%). <p align="">Conclusion: ECR is a highly sensitive and specific test for identification of memory impairment in AD and bvFTD, and can contribute to the differential diagnosis. We recommend it as highly useful test for clinical practice., and M. Urbanová, M. Vyhnálek, T. Nikolai, J. Michalec, K. Sheardová, J. Laczó, D. Hudeček, J. Hort
On the 14th May, on its annual general meeting the Learned Society of the Cezch Republic honored mathematician Prof. Miroslav Engliš and two young Czech scientists, N. Špačková and J. Čížek. The ceremony took part in Karolinum, a historical building of Charles University in Prague. and -red-.