Spectral monitoring of AGNs: Preliminary results for Ark 564 and Arp 102B

We present preliminary results of the long term spectral monitoring of two active galactic nuclei with different broad line shapes: Ark 564 and Arp 102B. Ark 564 is a bright nearby narrow line Syfert 1 (NLS1) galaxy with relatively narrow permitted optical emission lines and a high FeII/H${\beta}$ ratio, while Arp 102B is a nearby broad-line radio galaxy with broad double-peaked Balmer emission lines. The spectra of Ark 564 were observed during 11-year period (1999-2009) and the spectra of Arp 102B in the 12-year period (1998-2009), with SAO 6-m and 1-m telescopes (Russia) and the GHAO 2.1-m telescope (Cananea, Mexico).Comment: Presented on "8th Serbian Conference on Spectral Line Shapes in Astrophysics". In revised version minor changes in the tex

Influences of precipitation and temperature trend on maize yields

Maize yield for three decade period of the last century (1961-1990) were in Hungary for 15% higher than in Croatia (means 3.81 and 4.39 t/ha, respectively) and this trend was continued in the 1996-2007 period. However, amplitude of maize yields (differences among year (for the 1996-2007) in Hungary were higher (from 3.60 to 7.56 t/ha) than in Croatia (from 3.86 to 6.92 t/ha). Aim of this study was testing maize yield, precipitation and air-temperature variations in four Counties (Croatia: Vukovarsko-Srijemska =VSC and Virovitiţko-Podravska =VPC; Hungary: Békés = BC and Fejér =FC). Mean yield in VSC for 1996-2007 period was for 16% higher than in VPC. Yields in three less favorable years (LFY: 2000, 2003 and 2007) were considerably lower (means 5.22 and 4.41 t/ha, for VSC and VPC, respectively) than in three more favorable years (MFY: 1997, 2002 and 2005) years (means 7.50 and 7.00, respectively). Precipitation (means of two sites: Osijek and Virovitica) in 3-months period June-August was in LFY for 58% lower than in MFY (129 mm and 305 mm, respectively). At the same time, air-temperatures were for 2.0°C higher (22.7 and 20.7°C, respectively). Mean yield in BC for 1996-2007 period was for 21% higher than in FC. Yields in three LSY were considerably lower (means 3.78 and 3.79 t/ha, for BC and FC, respectively) than in three MFY (means 6.13 and 7.30 t/ha, respectively). Precipitation (means of two sites: Békéscsaba and Székesfehérvár) in 3-months period June-August was in LFY for 51% lower (115 mm and 235 mm, respectively) and air-temperatures were for 1.9°C higher (22.1 and 20.2°C, respectively) than in MFY. Precipitation and temperature trends for LFY and MFY in two sites of both countries were similar with emphasis that in Hungary they were negligible lower

Economics of water injected air screw compressor systems

There is a growing need for compressed air free of entrained oil to be used in industry. In many cases it can be supplied by oil flooded screw compressors with multi stage filtration systems, or by oil free screw compressors. However, if water injected screw compressors can be made to operate reliably, they could be more efficient and therefore cheaper to operate. Unfortunately, to date, such machines have proved to be insufficiently reliable and not cost effective. This paper describes an investigation carried out to determine the current limitations of water injected screw compressor systems and how these could be overcome in the 15-315 kW power range and delivery pressures of 6-10 bar. Modern rotor profiles and approach to sealing and cooling allow reasonably inexpensive air end design. The prototype of the water injected screw compressor air system was built and tested for performance and reliability. The water injected compressor system was compared with the oil injected and oil free compressor systems of the equivalent size including the economic analysis based on the lifecycle costs. Based on the obtained results, it was concluded that water injected screw compressor systems could be designed to deliver clean air free of oil contamination with a better user value proposition than the oil injected or oil free screw compressor systems over the considered range of operations

Normal Rack Grid Generation Method for Screw Machines with Large Helix Angles

Improving the efficiency of the screw machine is highly significant for industry. Numerical simulation is an important tool in developing these machines. The 3D computational fluid dynamic simulation can give a valuable insight into the flow parameters of screw machines. However, it is currently difficult to generate high quality computational grids required for screw rotors with large helix angle. This is mainly due to the excessively high cell skewness of the rotors with large helix angel, which would introduce errors in numerical simulation. This paper presents a novel grid generation algorithm used for the screw rotors with large helix angel. This method is based on the principles developed for the grid generation in transverse cross-section. Such mesh is generated by SCORGTM using normal rack grid generation method which means numerical meshes are generated in a plane normal to the pitch helix line. The mesh lines are then parallel to the helix line and thus an orthogonal mesh will be produced. The main flow and leakage flow directions are orthogonal to the mesh, potentially reducing numerical diffusion. This developed algorithm could also be employed for single screw machines

TEMPORAL EVOLUTION OF THERMAL STRUCTURES AND WINTER HEAT CONTENT CHANGE FROM VOS-XBT DATA IN THE CENTRAL MEDITERRANEAN SEA

Seasonal and year-to-year time evolution of the thermal structure, including the heat content change in the upper water column and its relationship with the surface net heat fluxes, have been studied at five locations in the central Mediterranean Sea. The study is based on temperature profiles collected during XBT surveys (eXpendable Bathy- Thermograph) carried out on ships of opportunity, in the framework of the MFSPP (Mediterranean Forecasting System Pilot Project), between September 1999 and May 2001. The five investigated zones are located in the southern Adriatic, NW Ionian, southern and northern Tyrrhenian, and Ligurian Sea. Gradual erosion of the thermocline in autumn, formation of a mixed layer in winter, and the onset of the stratification in spring, are common properties of the temporal evolution of thermal structures at all five locations. Moreover, in the southern Adriatic, a deep convection took place down to about 600m in winter 1999/2000. On the other hand, mild climatic conditions and small surface heat loss in autumn and winter 2000/2001 drastically reduced a mixing/ convection depth which hardly reached 200 m. Simultaneously, the NW Ionian remained slightly stratified throughout the winter period. The heat storage rate in the upper portion of the water column (down to 450 m) is compared with the air-sea net heat flux at a monthly scale. A heat content decrease is determined by the surface heat loss, and the processes such as lateral advection, or upwelling of the colder waters through the base of the water column (for example, in the southern Adriatic and Ionian Seas). Elsewhere (for example, in the northern Tyrrhenian and Ligurian Seas), the upwelling does not contribute significantly to the heat balance within the water column, since the vertical temperature gradients in deeper layers are negligible

Tailoring antiplatelet therapy in older patients with coronary artery disease

The older population represents a unique subset of patients due to a higher rate of comorbidities and risk factors, which can lead to a higher rate of ischemic and bleeding events. As a result, older adults are mainly underrepresented or excluded from randomized trials. Although the advancement in the percutaneous coronary intervention field with the development of new technologies, techniques, and potent antiplatelet therapy led to a reduction of ischemic risk, there is still a concern regarding bleeding hazards. Apart from the global utilization of less invasive trans-radial approach and proton pump inhibitors to reduce bleeding risk, proper tailoring of antiplatelet therapy in the older person is imperative. So far, several antiplatelet drugs have been introduced in different clinical scenarios, with dual antiplatelet therapy (combination of acetylsalicylic acid and P2Y12 inhibitor) recommended after percutaneous coronary intervention. The decision on the choice of antiplatelet drug and the DAPT duration is challenging and should be based on the relationship between ischemia and bleeding with the purpose of reducing ischemic events but not at the expense of increased bleeding complications. This is particularly important in the older population, where the evidence is obscure. The main objective of this review is to summarize the available evidence on contemporary antiplatelet therapy and different approaches of de-escalation strategies in older patients after percutaneous coronary intervention.What is the context?The older population represents a unique subset of patients due to a higher rate of comorbidities, risk factors, and unfavorable prognostic features, which can lead to a higher rate of ischemic and bleeding events. They are either excluded or underrepresented in most randomized clinical trials, which is why guidelines recommendation should be taken cautiously. Thus, the decision on the choice of antiplatelet therapy and its duration after percutaneous coronary intervention in older adults is challenging and should be tailored to a particular patient to avoid bleeding complications but not at the expense of increased ischemic events.What is new?In this review, we summarize all available evidence on contemporary antiplatelet therapy and different approaches of de-escalation strategies in older patients after percutaneous coronary intervention. In particular, several recommended approaches in patients with high bleeding risk, are thoroughly discussed in this review: De-escalation strategies with discontinuation of one antiplatelet drugDe-escalation strategy with switching between P2Y12 inhibitorsDe-escalation strategy based on dose reductionFinally, based on the current knowledge on factors contributing to high bleeding risk and the aforementioned antiplatelet modification approaches, in this review, we propose antiplatelet algorithm after percutaneous coronary intervention in older adults.What is the impact?The review provides comprehensive knowledge on antiplatelet therapy in older population and may help in tailoring antiplatelet therapy in this unique subset of patients

Long-term variability of the optical spectra of NGC 4151: II. Evolution of the broad Ha and Hb emission-line profiles

Results of the long-term (11 years, from 1996 to 2006) H$\alpha$ and H$\beta$ line variations of the active galactic nucleus of NGC 4151 are presented. High quality spectra (S/N>50 and R~8A) of H$\alpha$ and H$\beta$ were investigated. We analyzed line profile variations during monitoring period. Comparing the line profiles of H$\alpha$ and H$\beta$, we studied different details (bumps, absorption features) in the line profiles. The variations of the different H$\alpha$ and H$\beta$ line profile segments have been investigated. Also, we analyzed the Balmer decrement for whole line and for line segments. We found that the line profiles were strongly changing during the monitoring period, showing blue and red asymmetries. This indicates a complex BLR geometry of NGC 4151 with, at least, three kinematically distinct regions: one that contributes to the blue line wing, one to the line core and one to the red line wing. Such variation can be caused by an accelerating outflow starting very close to the black hole, where the red part may come from the region {closer to the black hole than the blue part, which is coming} from the region having the highest outflow velocities. Taking into account the fact that the BLR of NGC 4151 has a complex geometry (probably affected by an outflow) and that a portion of the broad line emission seems to have not a pure photoionization origin, one can ask the question whether the study of the BLR by reverberation mapping may be valid in the case of this galaxy.Comment: 24 pages, 18 figures, accepted for publications in A&