263 research outputs found
Cosmological interpretation of the color-magnitude diagrams of galaxy clusters
We investigate the color-magnitude diagram (CMD) of cluster galaxies in the
hierarchical -CDM cosmological scenario using both single stellar
populations and simple galaxy models. First, we analyze the effect of bursts
and mergers and companion chemical pollution and rejuvenation of the stellar
content on the integrated light emitted by galaxies. The dispersion of the
galaxy magnitudes and colors on the plane is mainly due to mixing
of ages and metallicities of the stellar populations, with mergers weighting
more than bursts of similar mass fractions. The analysis is made using the
Monte-Carlo technique applied to ideal model galaxies reduced to single stellar
populations with galaxy-size mass to evaluate mass, age and metallicity of each
object. We show that separately determining the contributions by bursts and
mergers leads to a better understanding of observed properties of CMD of
cluster galaxies. Then we repeat the analysis using suitable chemo-photometric
models of galaxies whose mass is derived from the cosmological predictions of
the galaxy content of typical clusters. Using the halo mass function and the
Monte-Carlo technique, we derive the formation redshift of each galaxy and its
photometric history. These are used to simulate the CMD of the cluster
galaxies. The main conclusion is that most massive galaxies have acquired the
red color they show today in very early epochs and remained the same ever
since. The simulations nicely reproduce the Red Sequence, the Green Valley and
the Blue Cloud, the three main regions of the CMD in which galaxies crowd.Comment: Accepted for publication in Ap
Effect of the essential oil of Minthostachys verticillata (Griseb.) epling and limonene on biofilm production in pathogens causing bovine mastitis
Bovine mastitis causes large annual economic losses around the world. Different microorganisms are associated with the disease. The capacity of pathogens to adhere to bovine mammary epithelial cells is associated with biofilm production which leads to antibiotic resistance. Research is now leading to search alternative control methods and medicinal plants constitute a natural, safe, effective and inexpensive option. Minthostachys verticillata is an autochthonous medicinal plant of Argentina with multiple ethnobotanical properties. In a previous study, we demonstrated that the essential oil (EO) of this species and limonene, one of its compounds, inhibited the growth of mastitis pathogens. The objective of the present work was to determine the inhibitory effect of the essential oil of M. verticillata and limonene, on biofilm formation and on mature biofilm produced by pathogens isolated from bovine mastitis. Time kill assay and bacterial lysis were also determined. Furthermore, RAPD-PCR assays were performed to determine changes in bacterial DNA after EO and limonene exposition. Bacterial isolates were identified as Escherichia coli (EC3 and EC9), Bacillus pumilus (BP5, BP6, and BP7) and Enterococcus faecium (EF1) by rRNA 16S sequencing and MALDI-TOF MS. All the strains were able to form biofilm. Addition of both lactose and sucrose did not affect biofilm production. MIC values for EO were 3.6 mg/ml for E. faecium; 0.9 mg/ml for E. coli (EC3), 14.5 mg/ml for E. coli (EC9), 1.8 mg/ml for B. pumilus (BP7), 3.63 mg/ml for B. pumilus (BP6) and 29.0 mg/ml for B. pumilus (BP7). MIC values for limonene were 6.6 mg/ml for B. pumilus (BP6) and 105 mg/ml for B. pumilus (BP5). These results demonstrated that EO was more effective than limonene, showing also bactericidal action against E. faecium (minimal inhibitory concentration (MBC) = 29.0 mg/ml). This result was corroborated by time of death assay, observing a cell decrease after at 6 h, and then by bacterial lysis assay. Both EO and limonene affected mature biofilm of isolated strains. The results contribute to the study of EO and limonene which may serve as a therapy against bovine mastitis pathogens inhibiting the development of pathogenic bacteria.Fil: Cerioli, Maria Florencia. Universidad Nacional de RĂo Cuarto; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Moliva, Melina Vanesa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Cariddi, Laura Noelia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; ArgentinaFil: Reinoso, Elina BeatrĂz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto; Argentin
The parallelism between galaxy clusters and early-type galaxies: I. The light and mass profiles
We have analyzed the parallelism between the properties of galaxy clusters
and early-type galaxies (ETGs) by looking at the similarity between their light
profiles. We find that the equivalent luminosity profiles of all these systems
in the \vfilt\ band, once normalized to the effective radius \re\ and shifted
in surface brightness, can be fitted by the S\'ersic's law \Sers\ and
superposed with a small scatter ( mag). By grouping objects in
different classes of luminosity, the average profile of each class slightly
deviates from the other only in the inner and outer regions (outside ), but the range of values of remains ample for the members of
each class, indicating that objects with similar luminosity have quite
different shapes. The "Illustris" simulation reproduces quite well the
luminosity profiles of ETGs, with the exception of in the inner and outer
regions where feedback from supernovae and active galactic nuclei, wet and dry
mergers, are at work. The total mass and luminosity of galaxy clusters as well
as their light profiles are not well reproduced. By exploiting simulations we
have followed the variation of the effective half-light and half-mass radius of
ETGs up to , noting that progenitors are not necessarily smaller in size
than current objects. We have also analyzed the projected dark+baryonic and
dark-only mass profiles discovering that after a normalization to the half-mass
radius, they can be well superposed and fitted by the S\'ersic's law.Comment: 25 pages, 19 figure
The mass assembly in galaxies and clusters: a new perspective from the luminosity profiles
Context: Galaxy clusters are the largest virialized structures in the observable Universe. Knowledge of their properties provides many useful astrophysical and cosmological information.
Aim: Our aim is to derive the luminosity and stellar mass profiles of the nearby galaxy clusters of the Omega-WINGS survey, to study the main scaling relations valid for such systems and to compare them with those valid for early-type galaxies (ETGs).
Methods: We merged data from the WINGS and Omega-WINGS databases, sorted the sources according to the distance from the brightest cluster galaxy (BCG), and calculated the integrated luminosity profiles in the B and V bands, taking into account extinction, photometric and spatial completeness, K correction, and background contribution. Then, by exploiting the spectroscopic sample we derived the stellar mass profiles of the clusters.
Results: We obtained the luminosity profiles of 46 galaxy clusters, reaching the virial radius in 30 cases, and the stellar mass profiles of 42 of our objects. We successfully fitted all the integrated luminosity growth profiles with one or two embedded SĂ©rsic components, deriving the main clusters parameters. We checked the main scaling relation among the clusters parameters in comparison with those obtained for a selected sample of ETGs of the same clusters.
Conclusions: We found that the nearby galaxy clusters are non-homologous structures such as ETGs and exhibit a color-magnitude (CM) red-sequence relation very similar to that observed for galaxies in clusters. These properties are not expected in the current cluster formation scenarios. In particular the existence of a CM relation for clusters, shown here for the first time, suggests that the baryonic structures grow and evolve in a similar way at all scales. We also provided an explanation of the properties of the fundamental plane relation of both clusters and ETGs in terms of a fine-tuning between the time-averaged star formation rate and the structural and dynamical characteristics of the system. Finally, we showed that the light profiles of clusters mirrors, in at least half cases, the light profile of the corresponding BCGs
First approaches in the study of cytotoxic and mutagenic damage induced by cold aqueous extract of Baccharis articulata on normal cells
Species of Genus Baccharis (Asteraceae) possess various bioactivities in vitro. The aim was to determine the cytogenotoxic activity of the cold aqueous extract (CAE) of Baccharis articulata. Peripheral blood lymphocytes from healthy individuals were in vitro faced to CAE (40, 78, 156, 313, 625 and 1250 ug/mL) for 18-24 h. Toxicity was evaluated by staining of trypan blue exclusion and MTT reduction. The genotoxicity was evaluated by the Micronucleus Test. Balb/c mice were injected with CAE (1800, 900 and 450 mg/kg), saline solution and cyclophosphamide as negative and positive controls respectively.
Animals were sacrificed at 6 h post-injection. Bone marrow samples were fixed and stained with May- GrĂŒnwald and Giemsa. Two thousand polychromatic erythrocytes (PCE) were counted to determine number
of micronuclei (MN) and normochromatic erythrocytes (NCE)/250 PCE to calculate toxicity index (TI). CAE toxicity on human lymphocytes was dose-dependent (Cytotoxic concentration 50% = 150 ug/mL). The
number of MNPCE for negative control was: 5 (+1), positive control: 372 (+23) and CAE in three doses: 26 (+8), 16 (+5) and 8 (+3). TI for negative control: 1.38 (+0.35) positive control: 3.1 (+1.06) and CAE in three doses: 0.78 (+0.05), 0.82 (+0.08) and 1.21 (+0.2). CAE treatment showed no statistical difference respect to negative control. CAE of B articulata was not cytogenotoxic.Fil: Cariddi, Laura Noelia. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Escobar, Franco Matias. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Sabini, Maria Carola. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Torres, Cristina Vanesa. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Zygadlo, Julio Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; ArgentinaFil: Sabini, Liliana Ines. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; Argentin
A search for peculiar stars in the open cluster Hogg 16
The study of chemically peculiar (CP) stars in open clusters provides
valuable information about their evolutionary status. Their detection can be
performed using the photometric system, which maps a characteristic
flux depression at \AA. This paper aims at studying the
occurrence of CP stars in the earliest stages of evolution of a stellar
population by applying this technique to Hogg 16, a very young Galactic open
cluster (about 25 Myr). We identified several peculiar candidates: two B-type
stars with a negative index (CD-60 4701, CPD-60 4706) are likely
emission-line (Be) stars, even though spectral measurements are necessary for a
proper classification of the second one; a third object (CD-60 4703),
identified as a Be candidate in literature, appears to be a background B-type
supergiant with no significant index, which does not rule out the
possibility that it is indeed peculiar as the normality line of for
supergiants has not been studied in detail yet. A fourth object (CD-60 4699)
appears to be a magnetic CP star of 8 M, but obtained spectral data
seem to rule out this hypothesis. Three more magnetic CP star candidates are
found in the domain of early F-type stars. One is a probable nonmember and
close to the border of significance, but the other two are probably pre-main
sequence cluster objects. This is very promising, as it can lead to very strong
constraints to the diffusion theory. Finally, we derived the fundamental
parameters of Hogg 16 and provide for the first time an estimate of its metal
content.Comment: Accepted for publication in New Astronomy. 9 pages, 4 figures, and 4
tables. A complete data table is available via CDS or upon request from the
corresponding autho
Efecto del aceite esencial de Minthostachys verticillata sobre la respuesta inmune de pacientes alérgicos a åcaros del polvo
El aceite esencial de hojas de M. verticillata fue obtenido por destilaciĂłn en corriente de vapor y analizado por cromatografĂa gaseosa. CĂ©lulas mononucleares de sangre perifĂ©rica de pacientes alĂ©rgicos, fueron estimuladas con aceite esencial. La proliferaciĂłn fue ensayada mediante mĂ©todo colorimĂ©trico del MTT o 3,(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide. Se cuantificaron cĂ©lulas CD4 + , CD8 + y B en cultivos de linfocitos y en sobrenadantes, IFN- Îł e IL-13. Se determinĂł la liberaciĂłn de la enzima ÎČ -hexosaminidasa de basĂłfilos adicionados de aceite esencial, y desafiados con el alergeno. Los efectos del aceite esencial fueron comparados con los de drogas antialĂ©rgicas. Los principales constituyentes identificados fueron pulegona, mentona y limoneno. Aceite esencial incrementĂł los valores de cĂ©lulas CD4 + , CD8 + y B (p<0.002), estimulĂł la sĂntesis de IFN- Îł y redujo los niveles de IL-13. El aceite esencial disminuyĂł la liberaciĂłn de ÎČ -hexosaminidasa de basĂłfilos (p<0.0001) con mayores efectos que los de las drogas ensayadas. Aceite esencial estimulĂł la desviaciĂłn Th1 y redujo la liberaciĂłn de la enzima ÎČ -hexosaminidasa de basĂłfilos de pacientes alĂ©rgicos.The essential oil from leaves of Minthostachys verticillata was obtained by steam distillation and analyzed by gas chromatography. Peripheral blood mononuclear cells from allergic patients were stimulated with essential oil. By application of MTT or 3,(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide colorimetric test the proliferation was assayed. In lymphocyte cultures CD4+, CD8+ and B cells were quantified, and in supernatants, IFN-Îł and IL-13. The liberation of ÎČ-hexosaminidase enzyme was determined for basophils with essential oil added and challenged with allergen and its effects were compared with those of anti-allergic drugs. The main constituents identified were pulegone, menthone and limonene. Essential oil increased absolute values of CD4+, CD8+ and B cells (p<0.002), stimulated IFN-Îł synthesis and reduced IL-13 levels. Essential oil diminished ÎČ-hexosaminidase liberation by basophils (p<0.0001), with effects majors to those of the drugs tested. Essential oil stimulated the Th1 deviation and reduced ÎČ-hexosaminidase enzyme liberation by basophils from allergic patientsFil: Cariddi, Laura Noelia. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Moser, Marina. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Andrada, Melisa. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Demo, Mirta Susana. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Zygadlo, Julio Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; ArgentinaFil: Sabini, Liliana Ines. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; ArgentinaFil: Maldonado, Ana Maria. Universidad Nacional de RĂo Cuarto. Facultad de Ciencias Exactas, FisicoquĂmicas y Naturales. Departamento de MicrobiologĂa e InmunologĂa; Argentin
In Vitro Screening of New Biological Limiters against Some of the Main Soil-Borne Phytopathogens
This study explored the role of Aphanocladium album (strain MX95), Pleurotus ostreatus (strain ALPO) and Pleurotus eryngii (strain AL142PE) as potential biological limiters. MX95, ALPO and AL142PE were screened under laboratory studies against Phytophthora nicotianae (PN), Fusarium oxysporum f. sp. radicis-lycopersici (FORL), Fusarium oxysporum f. sp. lycopersici (FOL), Fusarium solani (FS), Sclerotinia minor (SM), Sclerotinia sclerotiorum (SS), Athelia (Sclerotium) rolfsii (AR) and Verticillium dahliae (VD). The radial growth inhibition and the over-growth of potential antagonists on the targetorganisms were used to assess the interactions in the in vitro dual culture plate assay. The antagonistic ability of each challenge isolate was evaluated by calculating an index of the antagonism (AI) based on the interaction type in the dual cultures. MX95, reducing the growth of SS (20%) and FS (40%), displayed deadlock at mycelial contact against FOL and FORL, deadlock at distance versus VD and completely over-grew PN and SM. ALPO reduced (43 to 88%) the mycelial growth of tested pathogens except FORL and replaced PN and VD. AL142PE reducing (53 to 67%) SS, VD, FS and FOL mycelia growth and completely over-grew PN. AR showed combative ability against all the experienced biological limiters. Based on the results of the AI values, MX95 (AI = 16.5) was considered an active antagonist, while ALPO (AI = 11.5) and AL142PE (AI = 12.0) were moderately active antagonists. Strains MX95, ALPO and AL142PE were suitable as environment-friendly potential biocontrol agents to manage some of the main soil-borne agents of foot, root, soft rot and wilt diseases. These results are the first step in the assessment of the potential capacity of these organisms as biological limiters. Nevertheless, additional experiments should be performed for the translation to the field conditions in plant protection against soil-borne plant pathogens. In particular, the optimisation of dose and application time validation should be performed for a solid conclusion about the competitive ability of MX95, ALPO and AL142PE and the usefulness of potential biological limiters
Riesgos penales laborales. Un anaÌlisis criÌtico sobre el art. 316 del CP español y una propuesta de tipo penal de peligro para el ordenamiento juriÌdico argentino
Tesis doctoral ineÌdita leĂda en la Universidad AutoÌnoma de Madrid, Facultad de Derecho, Departamento de Derecho PuÌblico y FilosofiÌa JuriÌdica. Fecha de lectura: 8-09-2017Esta tesis tiene embargado el acceso al texto completo hasta el 08-03-201
PENGARUH EFISIENSI MODAL KERJA, LEVERAGE, LIKUIDITAS, TERHADAP PROFITABILITAS PADA PERUSAHAAN MAKANAN DAN MINUMAN YANG TERDAFTAR DI BEI PERIODE 2011-2015
Penelitian ini bertujuan untuk mengetahui pengaruh working capital
turnover, receivable turnover, inventory turnover, debt to asset ratio, debt to
equity ratio, current ratio terhadap profitabilitas pada perusahaan makanan
minuman yang terdaftar di Bursa Efek Indonesia pada tahun 2011-2015. Metode
analisis yang digunakan adalah analisis regresi data panel.
Hasil penelitian secara parsial menunjukan koefisien regresi variabel
working capital turnover tidak berpengaruh terhadap return on investment
ditunjukkan dengan nilai signifikan 0.2731>0.05; variabel receivable turnover
berpengaruh positif terhadap return on investment dengan nilai signifikan
0,0072<0,05; variabel inventory turnover tidak berpengaruh terhadap return on
investment dengan nilai signifikan 0,1177>0,05; variabel debt to asset ratio
berpengaruh negatif terhadap return on investment dengan nilai signifikan
0,0000<0,05; variabael debt to equity ratio tidak berpengaruh terhadap return on
investment dengan nilai signifikan 0,1276>0,05; variabel current ratio tidak
berpengaruh terhadap return on investment dengan nilai signifikan 0,6091<0,05.
Secara simultan variabel independen (working capital turnover, receivable
turnover, inventory turnover, debt to asset ratio, debt to equity ratio, current
ratio) secara bersama-sama berpengaruh signifikan terhadap variabel dependen
(return on investment) dengan nilai signifikan 0,000000<0,05.
Kata Kunci: Working Capital Turnover, Receivable Turnover, Inventory
Turnover, Debt To Asset Ratio, Debt To Equity Ratio, Current
Ratio, Return On Investment
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