The stability of the swirling flows with applications to hydraulic turbines

The presence of a large variety of vortex flows in nature and technology has raised many theoretical and numerical problems concerning the stability of such structures. In these conditions, in order to minimize the simulation requirements for nonlinear time-dependent problems, stability analyses of vortexmotions are of main importance in flow control problems. A particular case arises in the Francis turbines operate at partial discharge. The swirling flow downstream the runner becomes unstable inside the draft tube cone, with the development of a precessing helical vortex and associated severe pressure fluctuations [1]

ENTRAPMENT OF FLUORESCENT E. COLI CELLS IN ALGINATE GEL

By this experiment we will demonstrate the possibility to obtain genetically modifiedmicrobial strains that can be used as markers in different studies. The traittransferred in this study is the fluorescence in UV light expressed by a gene isolatedfrom jellyfish. This gene was insered into a plasmid carrying ampiciline resistanceand in the operon for arabinose fermentation. The plasmid was called pGLO. E coliHB101 K-12, ampicillin resistant colonies has been obtained. The colonies on theLB/amp/ara plate fluoresce green under UV light and the transformed colonies cangrow on ampicillin. Transformation efficiency = 362 transformed colonies/ μg DNA.The cells where immobilized by entrapment in alginate gel to study the phenomenoninvolved in cells immobilization. After immobilization in alginate gel, 5x104 cells ofE. coli pGLO / capsule and 1,4 x 105 cells of E. coli HB101/capsule has been found.Fluorescent microscopy revealed the presence of pGLO carrying cells into thecapsules. After cultivation of alginate capsules containing E. coli in LB broth, andfluorescent microscopy of the capsule sections, several observations of thephenomenon involved in continuous fermentation using biocatalysts in has beenmade. These cells grow and migrate to the cortical part of the matrix where they areimmobilized

Coronal jet contribution to the slow Solar wind flux: preliminary results

The solar wind is a continuous flux of charged particles that are ejected from the Sun's atmosphere. The sources of this flux have not been clearly identiffed yet. Coronal jets are proposed as a possible candidate. They are small collimated ejections of plasma seen in white-light coronagraph images. Using an existing catalogue, a sample of events during the period 2007-2008 was analysed, and ejected particle flux has been estimated. First results are now presented. As future work, all the jets contained in the catalogue will be analysed in order to obtain the average particle flux. The results will be compared to in-situ measurements in order to assess the coronal jet contribution to the solar wind

Stock markets and effective exchange rates in European countries: threshold cointegration findings

© 2015, Eurasia Business and Economics Society. The nexus between stock markets and exchange rates is examined in the case of eight European countries. The sample consists of four economies with national currencies and four that have adopted the euro. Thus, if differences between the two groups in the relationship governing the two markets exist, they will be unveiled. To this effect, a threshold cointegration methodology is adopted that allows for more reliable inferences to be drawn for both the short and long run nexus between the two markets. Monthly data is used covering the period 01/2000–12/2014. The findings reported herein offer support in favor of the portfolio approach thesis over the recent economic crisis period, but this finding is not the case for the entire sample. Bidirectional causality is found for Norway and the UK, pointing to a currency effect on stock markets. In view of the findings reported herein, policies aiming at reducing uncertainty in the stock markets can exert beneficial effects on currency markets

The use of antibiotic-loaded bone cement and systemic antibiotic prophylactic use in 2,971,357 primary total knee arthroplasties from 2010 to 2020: an international register-based observational study among countries in Africa, Europe, North America, and Oceania

Background and purpose - Antibiotic-loaded bone cement (ALBC) and systemic antibiotic prophylaxis (SAP) have been used to reduce periprosthetic joint infection (PJI) rates. We investigated the use of ALBC and SAP in primary total knee arthroplasty (TKA).Patients and methods - This observational study is based on 2,971,357 primary TKAs reported in 2010-2020 to national/regional joint arthroplasty registries in Australia, Den-mark, Finland, Germany, Italy, the Netherlands, New Zealand, Norway, Romania, South Africa, Sweden, Switzerland, the UK, and the USA. Aggregate-level data on trends and types of bone cement, antibiotic agents, and doses and duration of SAP used was extracted from participating registries.Results - ALBC was used in 77% of the TKAs with variation ranging from 100% in Norway to 31% in the USA. Palacos R+G was the most common (62%) ALBC type used. The primary antibiotic used in ALBC was gentamicin (94%). Use of ALBC in combination with SAP was common prac-tice (77%). Cefazolin was the most common (32%) SAP agent. The doses and duration of SAP used varied from one single preoperative dosage as standard practice in Bolzano, Italy (98%) to 1-day 4 doses in Norway (83% of the 40,709 TKAs reported to the Norwegian arthroplasty register). Conclusion - The proportion of ALBC usage in pri-mary TKA varies internationally, with gentamicin being the most common antibiotic. ALBC in combination with SAP was common practice, with cefazolin the most common SAP agent. The type of ALBC and type, dose, and duration of SAP varied among participating countries.Orthopaedics, Trauma Surgery and Rehabilitatio

Numele de măsură româneşti

Romanian measure phrases such as 'pahar de apă' (‘glass of water’) are analyzed as being headed by a semi-lexical category, in the form of N1. What is specific for Romanian measure phrases is the fact that they occupy a very low position on the grammaticalization scale, preserving most of their lexical properties, including the referent. As true quantity designators, they can constitute the answer to the question ‘how much’

Built-in challenges within the supervisory architecture of the Eurozone

We analyse a sample of significant European financial intermediaries that fall under the Single Supervisory Mechanism, which is part of the existing institutional supervisory architecture of the Eurozone. Theory suggests that herding among financial intermediaries raises cross-sectional correlations and has negative implications for systemic risk. Empirically, herding behaviours are associated with clusters identifying commonalities in asset allocations and risk strategies. By adopting a novel clustering approach, we analyse whether some pre-determined classifications and criteria associated with the current supervisory framework can capture financial intermediaries’ herding behaviour. We find that simple classifications and criteria, which are less likely to be policy-biased, can be more efficient than complex ones when it comes to identifying commonalities posing the highest threats to systemic risk. The findings confirm the need for a macro- rather than micro-prudential approach to financial supervision by highlighting the importance of using a supervisory toolkit that includes indicators with a stronger cross-sectional and network dimension. Our methodology can serve as a final consistency check for quantitative-based classifications and criteria employed by supervisory authorities. © 2021, The Author(s), under exclusive licence to Springer Nature Limited

Exposing volatility spillovers: a comparative analysis based on vector autoregressive models

We present a comparative analysis of two empirical methods grounded on a common vector autoregressive framework. In this setting, we investigate the time-varying nature and direction of volatility spillovers between some major stock indexes spanning across Europe, China and US. We find evidence that drawing on partial Granger causality brings more robust results than relying on the information provided by generalized impulse responses, especially when there is uncertainty about what other relevant factors need to be modelled