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Recent introduction of Gracilaria parvispora (Gracilariales, Rhodophyta) in Baja California, Mexico
Garcí,a-Rodrí,guez, Luis Daniel,Riosmena-Rodrí,guez, Rafael,Kim, Su Yeon,Ló,pez-Meyer, Melina,Orduñ,a-Rojas, Javier,Ló,pez-Vivas, Juan Manuel,Boo, Sung Min Walter de Gruyter GmbH 2013 Botanica marina Vol.56 No.2
Kubí,k, Petr,Š,ebek, Františ,ek,Petruš,ka, Jindř,ich,Hů,lka, Jiř,í,Park, Namsu,Huh, Hoon Elsevier 2018 Theoretical and applied fracture mechanics Vol.98 No.-
<P><B>Abstract</B></P> <P>This paper deals with a small punch test and ductile failure prediction of austenitic stainless steel 316L. Comprehensive investigation of fracture surfaces was conducted as well as examination of δ-ferrite and σ-phase present in the material in order to reveal the reason of occurrence of nonstandard type of fracture. Three phenomenological ductile fracture criteria were selected for comparative simulations regarding the prediction of crack initiation and propagation during the SPT. These criteria were calibrated by using the fracture tests of smooth cylindrical specimens, notched cylindrical specimens, notched tube specimens and cylinders with spherical recess. The whole material model including the fracture criteria with von Mises plasticity and element deletion technique for simulation of the crack initiation was implemented by using the user subroutine Vectorised User MATerial into the commercial finite element code of Abaqus. Finally, the simulation results with three ductile fracture criteria are compared and discussed based on the experimental results. Only one of the failure criteria captured the displacement at fracture correctly.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Wide range of stress states is experimentally described for AISI 316L. </LI> <LI> Detailed study of fracture surfaces produced by penetration tests. </LI> <LI> Non-standard cracking is observed due to ferrite phase. </LI> <LI> Uncoupled ductile fracture criteria are calibrated for austenitic stainless steel. </LI> </UL> </P>
Cardoso-Martí,nez, Faviola,de la Rosa, José,M.,Dí,az-Marrero, Ana R.,Darias, José,Cerella, Claudia,Diederich, Marc,Cueto, Mercedes The Royal Society of Chemistry 2015 Organic & Biomolecular Chemistry Vol.13 No.26
<P>Tanzawaic acids M (<B>1</B>), N (<B>2</B>), O (<B>3</B>) and P (<B>4</B>) and the known tanzawaic acids B (<B>5</B>) and E (<B>6</B>), have been isolated from an extract of a cultured marine-derived fungus (strain CF07370) identified as a member of the genus <I>Penicillium</I>. The structures of <B>1–4</B> were determined based on spectroscopic evidence. The antimicrobial and cytotoxic activities of compounds <B>1–6</B> were evaluated.</P> <P>Graphic Abstract</P><P>Tanzawaic acids M (<B>1</B>), N (<B>2</B>), O (<B>3</B>) and P (<B>4</B>) were isolated from an extract of a cultured marine-derived fungus (strain CF07370) identified as a member of the genus <I>Penicillium</I>. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5ob00773a'> </P>
Emission-line activity in type 2 quasars from the Sloan Digital Sky Survey
Villar-Martí,n, M.,Humphrey, A.,Martí,nez-Sansigre, A.,Pé,rez-Torres, M.,Binette, L.,Zhang, X. G. Blackwell Publishing Ltd 2008 Monthly notices of the Royal Astronomical Society Vol.390 No.1
<P>ABSTRACT</P><P>We have compared the optical emission-line ratios of type 2 quasars from Zakamska et al. with standard active galactic nucleus (AGN) photoionization model predictions, type 2 Seyfert galaxies, H <SMALL>II</SMALL> galaxies and narrow-line Fanaro–Riley type II radio galaxies. Moderate to high-ionization narrow-line radio galaxies and type 2 Seyfert galaxies are indistinguishable from type 2 quasars based on their optical line ratios. The standard AGN photoionization models, widely discussed for other type 2 AGN, can reproduce successfully the loci and trends of type 2 quasars in some of the main diagnostic diagrams. These models are not exempt of problems, and the discrepancies with the data are the same encountered for other type 2 AGN. As for these, realistic models must take into account a range of cloud properties, as widely demonstrated in the literature.</P><P>The Zakamska et al. sample is strongly biased towards objects with high line luminosities (L[O <SMALL>III</SMALL>] >10<SUP>42</SUP> erg s<SUP>−1</SUP>). We have found that stellar photoionization is obvious in a fraction of objects (3 out of 50) which are characterized by low [O <SMALL>III</SMALL>] luminosities compared with most type 2 quasars in the sample. We suggest that if the sample were expanded towards lower line luminosities (∼10<SUP>40–42</SUP> erg s<SUP>−1</SUP>) stellar photoionization might be evident much more frequently.</P><P>We explore an alternative scenario to pure AGN photoionization in which a varying contribution of stellar ionized gas contributes to the line fluxes. Although the models presented here are rather simplistic and not strong quantitative results can be extracted regarding the relative contribution of stellar versus AGN photoionization, our results suggest that adding a varying contribution of stellar photoionized gas works in the right direction to solve most of the problems affecting the standard AGN photoionization models. The ‘temperature problem’ on the other hand remains.</P>
<i>δ</i> Sct-type pulsations in eclipsing binary systems: Y Cam
Rodrí,guez, E.,Garcí,a, J. M.,Costa, V.,Lampens, P.,van Cauteren, P.,Mkrtichian, D. E.,Olson, E. C.,Amado, P. J.,Daszyń,ska-Daszkiewicz, J.,Turcu, V.,Kim, S.-L.,Zhou, A. Y.,Ló,p Blackwell Publishing Ltd 2010 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.408 No.4
<P>ABSTRACT</P><P>We present the results of a three-continent multisite photometric campaign carried out on the Algol-type eclipsing binary system Y Cam, in which the primary component is a multiperiodic δ Sct-type pulsator. The observations consist of 86 nights and more than 450 h of useful data collected mainly during the Northern winter 2002–2003. This means that this is the most extensive time series for such kind of systems obtained so far. These observations were collected mostly in the Johnson V filter, but they also include, for the first time, nearly complete binary light curves in simultaneous Strömgren <I>uvby</I> filters together with a few Crawford Hβ data obtained around the orbital phase of the first quadrature. A detailed photometric analysis is presented for both binarity and pulsation. The results indicate a semidetached system with the secondary filling its Roche lobe. No significant contribution from a third body is found. The residuals from the computed binary solution were then used to investigate the pulsational content of the primary component. The frequency analysis of the out-of-primary-eclipse data leads to a set of eight significant and independent pulsational peaks in a well-defined region of the frequency domain. This means that this is the largest set of excited modes discovered so far in the pulsating component of such kind of systems. The possibility of aliasing problems during the present run or short-term time-scale amplitude variations in some of them was investigated with null results. Indeed the results indicate that <I>f</I><SUB>1</SUB> and <I>f</I><SUB>3</SUB> form a frequency doublet with a beat period of <I>P</I><SUB>beat</SUB>= 17.065 d. Our results confirm the frequencies already detected by earlier authors and show the presence of some additional significant peaks. The observed amplitudes during the present run are also consistent with those derived from older data sets. We perform a preliminary mode identification for most of the frequencies on the basis of the collected multicolour photometry, the observed frequency spacings and the mode visibility in eclipsing binaries.</P>