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Wyszukujesz frazę "Friedman, A." wg kryterium: Autor


Wyświetlanie 1-11 z 11
Tytuł:
Role of iron in pathogenesis of Parkinson disease
Autorzy:
Galazka-Friedman, J.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/80638.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cell membrane
electron microscopy
ELISA test
ferritin
free radical
human brain
iron
lipid peroxidation
liver
neurodegeneration
oxidative stress
Parkinson's disease
pathogenesis
substantia nigra
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2011, 92, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hospitality, tourism, and events industry competency model: Human resource management implications
Model kompetencyjny w sektorze usług turystycznych – implikacje dla zarządzania zasobami ludzkimi
Autorzy:
Friedman, Barry A.
Powiązania:
https://bibliotekanauki.pl/articles/415141.pdf
Data publikacji:
2019-09
Wydawca:
Małopolska Wyższa Szkoła Ekonomiczna w Tarnowie
Tematy:
competency model
hospitality
tourism
human resource management
model kompetencyjny
hotelarstwo
turystyka
zarządzanie zasobami ludzkimi
Opis:
This paper addresses the implications of hospitality, tourism and events industry competency modeling on human resource management for organizations and employees. To facilitate organizational effectiveness, competency models must explicitly define knowledge skills and abilities in key jobs, link to overall organizational strategy, and align human resource management with business objectives. The Employment and Training Administration under the sponsorship of the United States Department of Labor developed the most comprehensive competency model for the hospitality, tourism and event industry. This model provides a framework that aligns recruitment, selection, onboarding training and development, performance management, total rewards, human resource planning, and even employees’ retirement in the hospitality, tourism and events industry. The paper concludes with competency model limitations and future research proposals.
W artykule poruszono problem wpływu modelowania kompetencji w branżach: hotelarskiej, turystycznej i eventowej, na zarządzanie zasobami ludzkimi na poziomie organizacji i jej pracowników. Aby zwiększyć efektywność organizacyjną, modele kompetencji muszą wyraźnie określać umiejętności i możliwości w zakresie kluczowych zadań, łączyć się z ogólną strategią organizacyjną i dostosowywać zarządzanie zasobami ludzkimi do celów biznesowych. W artykule przedstawiono kompleksowy model kompetencyjny dla branż: hotelarskiej, turystycznej i eventowej, opracowany przez Urząd ds. Zatrudnienia i Szkoleń działający przy Departamencie Pracy USA. Model ten pozwala regulować działania związane z rekrutacją, selekcją, szkoleniem i rozwojem nowych pracowników, zarządzaniem ich efektywnością, nagradzaniem, planowaniem rozwoju zasobów ludzkich, a nawet przechodzeniem na emeryturę osób zatrudnionych w wymienionych branżach. Wskazano ograniczenia tego modelu i podano propozycje dalszych badań w tym zakresie.
Źródło:
Zeszyty Naukowe Małopolskiej Wyższej Szkoły Ekonomicznej w Tarnowie; 2019, 3(43); 101-116
1506-2635
Pojawia się w:
Zeszyty Naukowe Małopolskiej Wyższej Szkoły Ekonomicznej w Tarnowie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generation of Intense Free-Electron Laser Radiation in the Terahertz Regime
Autorzy:
Pinhasi, Y.
Lurie, Y.
Pinhasi, G.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/1401876.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.60.Cr
52.59.Rz
Opis:
Free-electron lasers are high power radiation sources that utilize a distributed interaction between an accelerated electron beam and the electromagnetic field. In these devices, the electron beam serves as the amplification medium generating electromagnetic radiation, while propagating in a periodic magnetic structure called "wiggler" or "undulator". When electrons pass in the wiggler, they oscillate and act as a moving dipole emitting a wave packet of undulator synchrotron radiation. Incoherent summation of the wave packets results in a spontaneous emission. When the electrons are bunched into a short pulse, they all emit their wave packets in the same phase. The radiation wave packets combine coherently, resulting in super-radiance (where the energy radiated is proportional to the square of the electric charge). Such short bunches can be generated by an RF linear accelerator, driven by a photocathode injector. The radiation wavelength is determined by the velocity of the electrons and the spatial period of the undulator. The super-radiance mechanism enables the generation of intense radiation in frequency bands, whereas conventional sources fail to produce a powerful coherent radiation. In this article, we describe the design and analysis of ultrashort pulse free-electron laser operating at the sub-millimeter and terahertz regimes. The free-electron laser is based on a magnetostatic planar wiggler, in which super-radiant emission is emanated by accelerated electron bunches. A three-dimensional, space-frequency theory is developed in order to study radiation excitation in the wiggler. The total electromagnetic field (radiation and space-charge waves) is presented in the frequency domain as an expansion in terms of transverse eigenmodes of the (cold) cavity, in which the field is excited and propagates. The mutual interaction between the electron beam and the electromagnetic field is fully described by coupled equations, expressing the evolution of mode amplitudes and electron beam dynamics. The approach is applied in a numerical particle code WB3D, simulating wide-band interaction of a free-electron laser operating in the linear and non-linear regimes. The model is utilized to study spontaneous and super-radiant emissions radiated by an electron bunch at the sub-millimeter regime, taking into account three-dimensional space-charge effects emerging in such ultrashort bunches.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 315-318
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
T1 and T2 Relaxation Times from Substantia Nigra in Parkinsons Disease and Control
Autorzy:
Kuliński, R.
Szlachta, K.
Gałązka-Friedman, J.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/1360221.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.19.L-
Opis:
The diagnosis of Parkinson's disease, and also other neurodegenerative disorders, is based on clinical examination. Many attempts are undertaken to find a test that could confirm this clinical diagnosis. Many hopes were attributed to magnetic resonance imaging but its importance remains obscure. The aim of this study was to compare T1 and T2 relaxation times from substantia nigra of patients with clinical diagnosis of Parkinson's disease and age-matched controls. A decrease of T2 (54.5 ± 1.4 ms vs. 58.0 ± 1.5 ms) in Parkinson's disease vs. control was found with confidence level of 5%. T1 did not differ significantly between Parkinson's disease and control (624 ± 17 ms vs. 614 ± 21 ms).
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 869-871
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Different Signals of Magnetic Resonance Imaging and Ultrasound from Substantia Nigra in Parkinsons Disease and Control - Is Iron the Cause?
Autorzy:
Szlachta, K.
Sadowski, K.
Kuliński, R.
Gałązka-Friedman, J.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490100.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.19.L-
Opis:
Motor symptoms of Parkinson's disease are caused by a progressive degeneration of substantia nigra, a small structure located deep in the brain. The cause of this process is unknown but may be related to iron mediated oxidative stress. The aim of this study was to understand the mechanism of the change of magnetic resonance and ultrasound signals found in patients with Parkinson's disease, which were attributed by several authors to an important increase of the concentration of iron in substantia nigra. USG and MRI measurements were performed on phantoms simulating human brain to which high amounts of iron were introduced. The USG signal was unaffected by insertion of iron-loaded ferritin, while it was by insertion of glial tissue. Injections of iron-loaded ferritin and iron ions to the phantoms decreased $T_2$ relaxation time. Our results suggest that the observed change of the signal from Parkinsonian brains is probably due to a proliferation of glia and not to an increase of the concentration of iron.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 454-456
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An example of the application of Mössbauer spectroscopy for determination of concentration of iron in lyophilized brain tissue
Autorzy:
Rzepecka, P.
Duda, P.
Giebułtowicz, J.
Sochacka, M.
Friedman, A.
Gałązka-Friedman, J.
Powiązania:
https://bibliotekanauki.pl/articles/147214.pdf
Data publikacji:
2017
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Mössbauer spectroscopy
background spectrum
iron concentration
brain tissue
calibration curve
Opis:
Mössbauer spectroscopy is not routinely used for the determination of the concentration of iron. However, as this method does not need any pre-treatment of samples before measurements, it may be of extreme importance for the assessment of iron in samples, which can then be used for further investigations. Biological samples are a good example, however, as the concentrations of iron are very low in these, it is important to exclude possible artefacts from the background spectrum related to iron present in the counter and cryostat windows. The aim of this study was to compare two methods of determination of the amounts of iron in investigated sample: one, in which the background spectrum was subtracted from the sample spectrum measured, and the other, in which the obtained non-elaborated spectrum was fitted with two doublets – a doublet for the measured sample and a doublet for the background spectrum. Three samples containing known amounts of natural iron (400, 800 and 1600 µg) and a sample of lyophilized human brain tissue obtained from globus pallidus were assessed. Both methods led to the creation of a very good calibration curve with a correlation coefficient of 0.99. Although both methods gave similar results for the concentration of iron in the sample, the subtraction of the background spectrum had a significantly lower error of the final result.
Źródło:
Nukleonika; 2017, 62, 2; 159-163
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mössbauer Studies of Pathological Brain Tissues Affected by PSP Disease
Autorzy:
Gałązka-Friedman, J.
Bauminger, E.
Szlachta, K.
Schweitzer, K.
Wszolek, Z.
Dickson, D.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/1809541.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kx
Opis:
Progressive supranuclear palsy (PSP) is a neurological disease leading to the damage of two brain structures: globus pallidus and substantia nigra. The pathomechanism of this disease is still unknown. One of the hypotheses is oxidative stress. Oxidative stress is an overproduction of free radicals in which iron may be involved. To verify the hypothesis that iron may play a role in PSP we performed the Mössbauer comparative studies of pathological and control tissues. Ten samples of PSP globus pallidus, ten samples of PSP substantia nigra, twelve control samples of globus pallidus and nine control samples of substantia nigra were measured in a conventional Mössbauer spectrometer at 90 K. The Mössbauer spectra obtained for all samples showed well resolved doublets with an isomer shift of 0.46±0.01 mm/s and a quadruple splitting of 0.70±0.02 mm/s. The main difference in these preliminary studies was in the concentration of iron. The concentration in PSP samples in globus pallidus was found to be 257±19 ng/mg tissue, compared to 183±22 ng/mg in control samples and 301±26 ng/mg in substantia nigra compared to 188±22 ng/mg in control samples. Taking into consideration that we did not notice any substantial increase in iron concentration in Parkinsonian substantia nigra compared to control substantia nigra, but a substantial increase in both substantia nigra and globus pallidus in PSP, may suggest that iron plays a different role in the pathomechanisms of PSP and of Parkinson's disease.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 545-547
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Iron in Alzheimers and Control Hippocampi - Mössbauer, Atomic Absorption and ELISA Studies
Autorzy:
Gałązka-Friedman, J.
Bauminger, E.
Szlachta, K.
Koziorowski, D.
Tomasiuk, R.
Jaklewicz, A.
Wszołek, Z.
Dickson, D.
Kaplińska, K.
Friedman, A.
Powiązania:
https://bibliotekanauki.pl/articles/1506657.pdf
Data publikacji:
2011-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kx
Opis:
Alzheimer disease is a neurodegenerative process of unknown mechanism taking place in a part of the brain - hippocampus. Oxidative stress and the role of iron in it is one of the suggested mechanisms of cells death. In this study several methods were used to assess iron and iron binding compounds in human hippocampus tissues. Mössbauer spectroscopy was used for identification of the iron binding compound and determination of total iron concentration in 12 control and one Alzheimer disease sample of hippocampus. Mössbauer parameters obtained for all samples suggest that most of the iron is ferritin-like iron. The average concentration of iron determined by Mössbauer spectroscopy in control hippocampus was 45±10 ng/mg wet tissue. The average concentration of iron in 10 Alzheimer disease samples determined by atomic absorption was 66±13 ng/mg wet tissue. The concentration of H and L chains of ferritin in 20 control and 10 AD hippocampi was assessed with enzyme-linked immuno-absorbent assay. The concentration of H and L ferritin was higher in Alzheimer disease compared to control (19.36±1.51 vs. 5.84±0.55 ng/μg protein for H, and 1.39±0.25 vs. 0.55±0.10 for L). This 3-fold increase of the concentration of ferritin is accompanied by a small increase of the total iron concentration.
Źródło:
Acta Physica Polonica A; 2011, 119, 1; 81-83
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Catalogue of Martian Mössbauer Spectra
Autorzy:
Maliszewski, A.
Gałązka-Friedman, J.
Szlachta, K.
Urbanski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1506298.pdf
Data publikacji:
2011-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
91.25.F-
Opis:
The suggestion of sending a Mössbauer spectrometer to the surface of Mars was elaborated in 1988 year. In 1989 realization of this project was taken by scientists from Western Europe and USSR. Finally a Mössbauer spectrometer adapted to measurements on the surface of Mars was constructed by an international team under the guidance of G. Klingelhöfer. Mössbauer data from Mars are available for open public access on a web site of Planetary Data System. Based on these data the catalogue of Martian Mössbauer spectra was prepared and located on the web site of one of the author (JGF). The aim of the construction of this catalogue was to create the possibility to compare quickly spectra from different places on the Martian surface.
Źródło:
Acta Physica Polonica A; 2011, 119, 1; 10-11
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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