We assessed the effect of different doses of vitamin D supplementation on microcirculation, signs and symptoms of peripheral neuropathy and inflammatory markers in patients with type 2 diabetes ...(T2DM). Sixty-seven patients with T2DM and peripheral neuropathy (34 females) were randomized into two treatment groups: Cholecalciferol 5000 IU and 40,000 IU once/week orally for 24 weeks. Severity of neuropathy (NSS, NDS scores, visual analogue scale), cutaneous microcirculation (MC) parameters and inflammatory markers (ILs, CRP, TNFα) were assessed before and after treatment. Vitamin D deficiency/insufficiency was detected in 78% of the 62 completed subjects. Following treatment with cholecalciferol 40,000 IU/week, a significant decrease in neuropathy severity (NSS,
= 0.001; NDS,
= 0.001; VAS,
= 0.001) and improvement of cutaneous MC were observed (
< 0.05). Also, we found a decrease in IL-6 level (2.5 pg/mL vs. 0.6 pg/mL,
< 0.001) and an increase in IL-10 level (2.5 pg/mL vs. 4.5 pg/mL,
< 0.001) after 24 weeks of vitamin D supplementation in this group. No changes were detected in the cholecalciferol 5000 IU/week group. High-dose cholecalciferol supplementation of 40,000 IU/week for 24 weeks was associated with improvement in clinical manifestation, cutaneous microcirculation and inflammatory markers in patients with T2DM and peripheral neuropathy.
The popularity of econometric analyses that include variables obtained from text mining is growing rapidly. A frequently applied approach is to identify topics from large corpora, which makes it ...possible to determine trends that reflect the changing relevance of topics over time. We address the question of whether such topic trends are linked to quantitative economic indicators typically used for analysing the objects described by a topic. The analysis is based on academic economic articles from Poland and Germany from 1984 to 2020. There is a specific focus on whether relationships between topic trends and indicators are similar across national economies. The connection between topic trends and indicators is analysed using vector autoregressive models and Granger causality tests.
W ostatnim czasie obserwować można gwałtowny wzrost popularności metod analizy ekonomicznej wykorzystującej zmienne pozyskane z tekstów. Jednym z najczęściej stosowanych podejść jest modelowanie tematów, które pozwala na oszacowanie, jak waga poszczególnych tematów zmieniała się w czasie. Celem artykułu jest zbadanie, czy mierzona za pomocą wag popularność tematów była powiązana z wybranymi zmiennymi ekonomicznymi. W badaniu wykorzystano artykuły naukowe z obszaru ekonomii, opublikowane w Polsce i Niemczech w latach 1984–2020. Jednym z celów analizy było stwierdzenie, czy zależności pomiędzy popularnością wybranych tematów w Polsce i w Niemczech i powiązanymi z nimi wskaźnikami ekonomicznymi były podobne. Badanie przeprowadzono za pomocą modeli wektorowej autoregresji i testów przyczynowości Grangera.
In impulse response analysis estimation uncertainty is typically displayed by constructing bands around estimated impulse response functions. If they are based on the joint asymptotic distribution ...possibly constructed with bootstrap methods in a frequentist framework, often individual confidence intervals are simply connected to obtain the bands. Such bands are known to be too narrow and have a joint coverage probability lower than the desired one. If instead the Wald statistic is used and the joint bootstrap distribution of the impulse response coefficient estimators is taken into account and mapped into the band, it is shown that such a band is typically rather conservative. It is argued that, by using the Bonferroni method, a band can often be obtained which is smaller than the Wald band.
Nanostructured hydroxyapatite (HAP) and its nanoparticles are widely used for implantation into the human organism. The biocompatibility of the implants depends very much on the interaction between ...the implant and the cells regenerating tissue to be connected to the implant. An implant surface electrical charged density plays an important role in these processes. Possible instruments managing the surface electrical potential of HAP are in the focus of this paper. Both theoretical and experimental results evidence that:
- the surface electrical charge density of the nanoparticle depends on its size and shape;
- the electrical charge density of HAP could be engineered by contact less technique because of deposition of the electrical charge from the external radiation source, surface couples reconstruction.
Display omitted
•Biomaterial surface electric charge plays a significant role in sorption of microorganisms.•The surface electrical charge density of the nanoparticles depends on its size.•Engineering of HAp electrical charge density is possible by different methods.
Cross-Corpora Comparisons of Topics and Topic Trends Bystrov, Victor; Naboka, Viktoriia; Staszewska-Bystrova, Anna ...
Jahrbücher für Nationalökonomie und Statistik,
08/2022, Letnik:
242, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Textual data gained relevance as a novel source of information for applied economic research. When considering longer periods or international comparisons, often different text corpora have to be ...used and combined for the analysis. A methods pipeline is presented for identifying topics in different corpora, matching these topics across corpora and comparing the resulting time series of topic importance. The relative importance of topics over time in a text corpus is used as an additional indicator in econometric models and for forecasting as well as for identifying changing foci of economic studies. The methods pipeline is illustrated using scientific publications from Poland and Germany in English and German for the period 1984–2020. As methodological contributions, a novel tool for data based model selection, sBIC, is impelemented, and approaches for mapping of topics of different corpora (including different languages) are presented.
Inference on impulse response functions from vector autoregressive models is commonly done using bootstrap methods. These methods can be inaccurate in small samples and for persistent processes. This ...article investigates the construction of skewness-adjusted confidence intervals and joint confidence bands for impulse responses with improved small sample performance. We suggest to adjust the skewness of the bootstrap distribution of the autoregressive coefficients before the impulse response functions are computed. Using extensive Monte Carlo simulations, the approach is shown to improve the coverage accuracy in small- and medium-sized samples and for unit-root processes.
In this work, computational molecular modeling and exploration was applied to study the nature of the negative piezoelectric effect in the ferroelectric polymer polyvinylidene fluoride (PVDF), and ...the results confirmed by actual nanoscale measurements. First principle calculations were employed, using various quantum-chemical methods (QM), including semi-empirical (PM3) and various density functional theory (DFT) approaches, and in addition combined with molecular mechanics (MM) methods in complex joint approaches (QM/MM). Both PVDF molecular chains and a unit cell of crystalline β-phase PVDF were modeled. This computational molecular exploration clearly shows that the nature of the so-called negative piezo-electric effect in the ferroelectric PVDF polymer has a self-consistent quantum nature, and is related to the redistribution of the electron molecular orbitals (wave functions), leading to the shifting of atomic nuclei and reorganization of all total charges to the new, energetically optimal positions, under an applied electrical field. Molecular modeling and first principles calculations show that the piezoelectric coefficient
d
33
has a negative sign, and its average values lies in the range of
d
33
~ −16.6 to −19.2 pC/N (or pm/V) (for dielectric permittivity ε = 5) and in the range of
d
33
~ −33.5 to −38.5 pC/N (or pm/V) (for ε = 10), corresponding to known data, and allowing us to explain the reasons for the negative sign of the piezo-response. We found that when a field is applied perpendicular to the PVDF chain length, as polarization increases the chain also stretches, increasing its length and reducing its height. For computed value of ε ~ 5 we obtained a value of d
31
~ +15.5 pC/N with a positive sign. This computational study is corroborated by measured nanoscale data obtained by atomic force and piezo-response force microscopy (AFM/PFM). This study could be useful as a basis for further insights into other organic and molecular ferroelectrics.
The goal of the paper is to investigate the estimation precision of forecast error variance decomposition (FEVD) based on stable structural vector autoregressive models identified using short run and ...long run restrictions. The analysis is performed by means of Monte Carlo experiments. It is demonstrated that for processes with roots close to one, selected FEVD parameters can be estimated more accurately using recursive restrictions on the long run multipliers than under recursive restrictions on the impact effects of shocks. This finding contributes to the discussion of pros and cons of using alternative identification schemes by providing counterexamples for the notion that short run identifying restrictions lead to smaller estimation errors than long run restrictions. // Celem artykułu jest zbadanie dokładności estymacji parametrów dekompozycji wariancji błędów prognozy dla strukturalnych modeli wektorowej autoregresji zidentyfikowanych z użyciem restrykcji na parametry krótko i długookresowe. W analizie wykorzystano eksperymenty Monte Carlo. Wykazano, że dla procesów o pierwiastkach, których wartość zbliżona jest do jedności, wybrane parametry dekompozycji wariancji błędów prognozy można oszacować z większą precyzją przy założeniu trójkątnej macierzy mnożników długookresowych niż przy restrykcji trójkątnej macierzy mnożników bezpośrednich. Uzyskane wyniki wnoszą wkład do dyskusji dotyczącej zalet i wad różnych schematów identyfikacji przez wskazanie kontrprzykładów dla hipotezy, że wykorzystanie restrykcji krótkookresowych prowadzi do mniejszych błędów szacunku niż zastosowanie restrykcji na parametry długookresowe.
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