Influence of Giant CCN on warm rain processes in the ECHAM5 GCM

International audienceIncreased Cloud Condensation Nuclei (CCN) load due to anthropogenic activity might lead to non-precipitating clouds because the cloud drops become smaller (for a constant liquid water content) and, therefore, less efficient in rain formation (aerosol indirect effect). Adding giant CCN (GCCN) into such a cloud can initiate precipitation (namely, drizzle) and, therefore, might counteract the aerosol indirect effect. The effect of GCCN on global climate, especially on clouds and precipitation, within a General Circulation Model (GCM) is investigated. GCCN are aerosol particles larger than 5?10 ?m in radius that can act as cloud condensation nuclei. One prominent GCCN species is sea salt. Sea salt concentrations depend mainly on wind speed but also on relative humidity, stability and precipitation history. Natural variability is much larger than the simulated one because sea salt emissions within ECHAM5 are a function of wind speed only. Giant sea salt concentrations in ECHAM5 are determined by using the tail of the coarse mode aerosol distribution with cutoff radii of 5 ?m or 10 ?m. It is assumed that activated GCCN particles directly form rain drops (of 25 ?m size). Thereby, the added rain water mass and number stems from the redistribution of the condensed water into cloud and rain water according to the number of activated GCCN. As the formed precipitation is most likely drizzle with rather small drops a prognostic rain scheme is applied to account for the lower fall speeds and, therefore, slower sedimentation of the drizzle drops. The ECHAM5 simulations with incorporated GCCN show that precipitation is affected only locally. Cloud properties like liquid water and cloud drop number show a larger sensitivity to GCCN. On the one hand, the increased rain water mass causes an increase in the accretion rate and, therefore, in the rain production. On the other hand, very high GCCN concentrations can lead to an artificially exaggerated transfer of cloud water to the rain class which then results in a strong decrease of the conversion rate and the rain production. The introduction of the GCCN reduces the anthropogenic increase of liquid water in the atmosphere from pre-industrial to present day because clouds are precipitating faster in the presence of the GCCN. Hence, the accumulation of liquid water in the atmosphere is reduced. According to those changes in the cloud properties, the radiative budget is also changing. The GCCN cause a reduction of the anthropogenic aerosol indirect effect of about 0.1?0.25 W m?2 which corresponds to 5?10% of the total effect. Thus, the GCCN in ECHAM5 partly offset the anthropogenic aerosol indirect effect

Influence of Giant CCN on warm rain processes in the ECHAM5 GCM

Predmet rada je detektirati i analizirati kanale distribucije proizvoda za njegu kose. U tu svrhu su obrađeni dostupni sekundarni izvori informacija te je provedeno empirijsko istraživanje na uzorku poznavatelja metodom dubinskog intervjua. Kanali distribucije proizvoda za njegu kose u Hrvatskoj su u većini slučajeva neizravni s jednim ili više posrednika. Posrednici mogu biti distributeri, veleprodaje, maloprodaje, ljekarne, frizerski saloni, drogerije, internet prodaja itd. Izbor posrednika ovisi o segmentu u kojem se proizvodi za kosu prodaju, a on može biti luksuzne, dermatološke, profesionalne prirode ili za masovnu potrošnju. Kod proizvoda za njegu kose se tržište značajno izmijenilo razvojem digitalne tehnologije. Kako bi pojedina marka uspjela, mora prije svega osluškivati postojeće i nadolazeće trendove, biti inovativna u razvoju proizvoda, pružiti prirodnost barem u dijelu svog asortimana, poznavati svoju ciljanu skupinu potrošača te njihove potrebe, navike i preferencije i na temelju toga pronaći dodanu vrijednost proizvoda koju im može ponuditi. Nakon toga mora pomno odabrati kanale distribucije, ali i tu treba biti vrlo fleksibilna i prilagođavati se čestim promjenama. Svakako mora biti prisutna online, imati svoju web stranicu, Facebook i Instagram profil, You Tube i IGTV kanal i mrežu influencera. Oni moraju biti pažljivo odabrani da svojim modnim, verbalnim i osobnim izričajem odgovaraju vrijednostima marke jer samo tako mogu biti vjerodostojni. Osim toga, vrlo je bitno da pratitelji influencera čine ciljanu skupinu marke kako bi se osiguralo doticanje pravih potencijalnih kupaca. U svim segmentima obraćanja publici, marka mora prenositi istu poruku jer je sve više kupaca koji informacije o proizvodima prikupljaju iz više različitih izvora. U porastu je prodaja putem interneta na koju se kupci odlučuju nakon što su se informirali na samom prodajnom mjestu ili također online. Zato je vrlo važno da svi sudionici kanala budu educirani o proizvodima, ali i da poznaju svoje kupce. No, to više nije dovoljno, oni moraju biti i i vrsni prodavači. Stoga se sve više ulaže u edukacije i načine motiviranja posrednika između proizvođača i potrošača jer su ovi potonji postali dosta zahtjevni i upućeni u ono što žele, kako mogu do toga doći i uz koje uvjete. Ni najbolji proizvodi za kosu se ne mogu uspješno prodati ukoliko se ne omogući dostupnost tih proizvoda na mjestima gdje i kada ju potrošači žele kupiti.The subject of this thesis is to detect and analyze distribution channels of hair care products. For this purpose, available secondary sources of information were processed and empirical research on a sample of experts was conducted through a deep interview method. Distribution channels of hair care products in Croatia are in most cases indirect with one or more intermediaries. Intermediary can be distributors, wholesalers, retailers, pharmacies, hairdressers, drugstores, internet sales, etc. The selection of mediators depends on the segment in which hair products are sold and it can be of luxurious nature, dermatologic, professional or mass market. Regarding hair care products, the market has significantly changed with the development of digital technology. In order for each brand to succeed, it must primarily listen to existing and upcoming trends, be innovative in product development, provide naturalness in at least part of its range, know its target consumer group and their needs, habits and preferences and find added value of products to offer them. Thereafter, it is necessary to carefully select distribution channels, but also be very flexible and adapt them to the frequent changes. Brand must be present online, have its website, Facebook and Instagram profiles, You Tube and IGTV channels and influencers network. They have to be carefully selected and present the brand's values by their personal, fashion and verbal expressions to ensure their credibility. Additionally, it is very important that influencer's followers are part of brand's target group to ensure that they are touching the right potential buyers. In all segments of addressing the audience, the brand has to deliver the same message because customers receive product information from a variety of sources. Online sales is growing and buyers buy online after they have been informed about products at the point of sale or online. That is why it is very important for all channel participants to be educated about products, but also to know their customers. That is not enough anymore; they must be excellent sellers as well. Therefore, investment in education and ways of motivating intermediaries between producers and consumers are rising, because the latter have become highly demanding and acquainted to what they want, how they can get it and under what conditions. Even the best hair products cannot be successfully sold unless you ensure that these products are available in places where and when consumers want to buy it

Chandra observations of the old pulsar PSR B1451-68

We present 35 ks Chandra ACIS observations of the 42 Myr old radio pulsar PSR B1451-68. A point source is detected 0.32" +/- 0.73" from the expected radio pulsar position. It has ~200 counts in the 0.3-8 keV energy range. We identify this point source as the X-ray counterpart of the radio pulsar. PSR B1451-68 is located close to a 2MASS point source, for which we derive 7% as the upper limit on the flux contribution to the measured pulsar X-ray flux. The pulsar spectrum can be described by either a power-law model with photon index Gamma=2.4 (+0.4/-0.3) and a unrealistically high absorbing column density N(H)= (2.5 (+1.2/-1.3)) * 10^(21) cm^-2, or by a combination of a kT=0.35 (+0.12/-0.07) keV blackbody and a Gamma = 1.4 +/- 0.5 power-law component for N(H)[DM]= 2.6 * 10^(20) cm^-2, estimated from the pulsar dispersion measure. At the parallactic, Lutz-Kelker bias corrected distance of 480 pc, the non-thermal X-ray luminosities in the 0.3-8 keV energy band are either Lx(nonth)= (11.3 +/- 1.7) * 10^(29) erg/s or Lx(nonth)= (5.9 (+4.9/-5.0)) * 10^(29) erg/s, respectively. This corresponds to non-thermal X-ray efficiencies of either eta(nonth)= Lx(nonth) / (dE/dt) ~ 0.005 or 0.003, respectively.Comment: 19 pages, 9 figures, 2 tables, accepted by Ap

Space cowboys odyssey: beyond the Gould Belt

We present our new advanced model for population synthesis of close-by cooling NSs. Detailed treatment of the initial spatial distribution of NS progenitors and a detailed ISM structure up to 3 kpc give us an opportunity to discuss the strategy to look for new isolated cooling NSs. Our main results in this respect are the following: new candidates are expected to be identified behind the Gould Belt, in directions to rich OB associations, in particular in the Cygnus-Cepheus region; new candidates, on average, are expected to be hotter than the known population of cooling NS. Besides the usual approach (looking for soft X-ray sources), the search in 'empty' $\gamma$-ray error boxes or among run-away OB stars may yield new X-ray thermally emitting NS candidates.Comment: 3 pages, 2 figures, proceedings of the conference "40 Years of Pulsars ", 12-17 August 2007, Montreal, Canad

The Magnificent Seven in the dusty prairie -- The role of interstellar absorption on the observed neutron star population

The Magnificent Seven have all been discovered by their exceptional soft X-ray spectra and high ratios of X-ray to optical flux. They all are considered to be nearby sources. Searching for similar neutron stars with larger distances, one expects larger interstellar absorption resulting in harder X-ray counterparts. Current interstellar absorption treatment depends on chosen abundances and scattering cross-sections of the elements as well as on the 3D distribution of the interstellar medium. After a discussion of these factors we use the comprehensive 3D measurements of the Local Bubble by Lallement et al. 2003 to construct two simple models of the 3D distribution of the hydrogen column density. We test these models by using a set of soft X-ray sources with known distances. Finally, we discuss possible applications for distance estimations and population synthesis studies

SGRs and AXPs proposed as ancestors of the Magnificent seven

The recently suggested correlation between the surface temperature and the magnetic field in isolated neutron stars does not seem to work well for SGRs, AXPs and X-ray dim isolated neutron stars (XDINs; specifically the Magnificent Seven or M7). Instead by appealing to a Color-Flavor Locked Quark Star (CFLQS) we find a more natural explanation. In this picture, the heating is provided by magnetic flux expulsion from a crust-less superconducting quark star. Combined with our previous studies concerning the possibility of SGRs, AXPs, and XDINs as CFLQSs, this provides another piece of evidence that these objects are all related. Specifically, we propose that XDINs are the descendants of SGRs and AXPs.Comment: submitted to A&A letters to the edito

Molecular Characterisation of Bacterial Wilt Resistance in \u3cem\u3eLolium Multiflorum\u3c/em\u3e Lam.

Italian ryegrass (Lolium multiflorum Lam.), a forage grass of prime importance throughout the world, is adversely affected by the pathogen Xanthomonas translucens pv graminis. Breeding for resistant cultivars is the only practicable means of disease control. However, the inheritance of bacterial wilt resistance is largely unknown. The aim of our research is to elucidate genetic control of bacterial wilt resistance using molecular technologies such as genetic linkage mapping and the analysis of quantitative trait loci (QTL)

Nothing to hide: An X-ray survey for young stellar objects in the Pipe Nebula

We have previously analyzed sensitive mid-infrared observations to establish that the Pipe Nebula has a very low star-formation efficiency. That study focused on YSOs with excess infrared emission (i.e, protostars and pre-main sequence stars with disks), however, and could have missed a population of more evolved pre-main sequence stars or Class III objects (i.e., young stars with dissipated disks that no longer show excess infrared emission). Evolved pre-main sequence stars are X-ray bright, so we have used ROSAT All-Sky Survey data to search for diskless pre-main sequence stars throughout the Pipe Nebula. We have also analyzed archival XMM-Newton observations of three prominent areas within the Pipe: Barnard 59, containing a known cluster of young stellar objects; Barnard 68, a dense core that has yet to form stars; and the Pipe molecular ring, a high-extinction region in the bowl of the Pipe. We additionally characterize the X-ray properties of YSOs in Barnard 59. The ROSAT and XMM-Newton data provide no indication of a significant population of more evolved pre-main sequence stars within the Pipe, reinforcing our previous measurement of the Pipe's very low star formation efficiency.Comment: Accepted for publication in Ap

Aerosol size-dependent below-cloud scavenging by rain and snow in the ECHAM5-HAM

Wet deposition processes are highly efficient in the removal of aerosols from the atmosphere, and thus strongly influence global aerosol concentrations, and clouds, and their respective radiative forcings. In this study, physically detailed size-dependent below-cloud scavenging parameterizations for rain and snow are implemented in the ECHAM5-HAM global aerosol-climate model. Previously, below-cloud scavenging by rain in the ECHAM5-HAM was simply a function of the aerosol mode, and then scaled by the rainfall rate. The below-cloud scavenging by snow was a function of the snowfall rate alone. The global mean aerosol optical depth, and sea salt burden are sensitive to the below-cloud scavenging coefficients, with reductions near to 15% when the more vigorous size-dependent below-cloud scavenging by rain and snow is implemented. The inclusion of a prognostic rain scheme significantly reduces the fractional importance of below-cloud scavenging since there is higher evaporation in the lower troposphere, increasing the global mean sea salt burden by almost 15%. Thermophoretic effects are shown to produce increases in the global and annual mean number removal of Aitken size particles of near to 10%, but very small increases (near 1%) in the global mean below-cloud mass scavenging of carbonaceous and sulfate aerosols. Changes in the assumptions about the below-cloud scavenging by rain of particles with radius smaller than 10 nm do not cause any significant changes to the global and annual mean aerosol mass or number burdens, despite a change in the below-cloud number removal rate for nucleation mode particles by near to five-fold. Annual and zonal mean nucleation mode number concentrations are enhanced by up to 30% in the lower troposphere with the more vigourous size-dependent below-cloud scavenging. Closer agreement with different observations is found when the more physically detailed below-cloud scavenging parameterization is employed in the ECHAM5-HAM model

Small Angle Scattering by Fractal Aggregates: A Numerical Investigation of the Crossover Between the Fractal Regime and the Porod Regime

Fractal aggregates are built on a computer using off-lattice cluster-cluster aggregation models. The aggregates are made of spherical particles of different sizes distributed according to a Gaussian-like distribution characterised by a mean $a_0$ and a standard deviation $\sigma$. The wave vector dependent scattered intensity $I(q)$ is computed in order to study the influence of the particle polydispersity on the crossover between the fractal regime and the Porod regime. It is shown that, given $a_0$, the location $q_c$ of the crossover decreases as $\sigma$ increases. The dependence of $q_c$ on $\sigma$ can be understood from the evolution of the shape of the center-to-center interparticle-distance distribution function.Comment: RevTex, 4 pages + 6 postscript figures, compressed using "uufiles", published in Phys. Rev. B 50, 1305 (1994