The Phoenix Deep Survey: The 1.4 GHz microJansky catalogue

The initial Phoenix Deep Survey (PDS) observations with the Australia Telescope Compact Array have been supplemented by additional 1.4 GHz observations over the past few years. Here we present details of the construction of a new mosaic image covering an area of 4.56 square degrees, an investigation of the reliability of the source measurements, and the 1.4 GHz source counts for the compiled radio catalogue. The mosaic achieves a 1-sigma rms noise of 12 microJy at its most sensitive, and a homogeneous radio-selected catalogue of over 2000 sources reaching flux densities as faint as 60 microJy has been compiled. The source parameter measurements are found to be consistent with the expected uncertainties from the image noise levels and the Gaussian source fitting procedure. A radio-selected sample avoids the complications of obscuration associated with optically-selected samples, and by utilising complementary PDS observations including multicolour optical, near-infrared and spectroscopic data, this radio catalogue will be used in a detailed investigation of the evolution in star-formation spanning the redshift range 0 < z < 1. The homogeneity of the catalogue ensures a consistent picture of galaxy evolution can be developed over the full cosmologically significant redshift range of interest. The 1.4 GHz mosaic image and the source catalogue are available on the web at http://www.atnf.csiro.au/~ahopkins/phoenix/ or from the authors by request.Comment: 16 pages, 11 figures, 4 tables. Accepted for publication by A

Suplementação mineral para bovinos de corte no Pantanal (Sub-região da Nhecolândia).

Os levantamentos de concentrações de minerais nas pastagens e nos tecidos de bovinos feitos em algumas sub-regiões do Pantanal indicaram ocorrência de deficiências acentuadas, principalmente de cálcio e fósforo. Baseado nesse trabalho, a Embrapa Pantanal elaborou cinco fórmulas de suplemento mineral para diferentes sub-regiões do Pantanal

Do fiscal imbalances deteriorate sovereign debt ratings ?

We use sovereign debt rating estimations from Afonso, Gomes and Rother (2009, 2011) for Fitch, Moody’s, and Standard & Poor’s, to assess to what extent the recent fiscal imbalances are being reflected on the sovereign debt notations. With macro and fiscal data up to 2010, and macro and fiscal projections, we obtain the expected rating for several OECD countries. The answer to the title question is yes, but in a diverse way for each country. Our average model predictions point to a heterogeneous behaviour of rating agencies across countries

Radio observations of the CDF-South: a possible link between radio emission and star formation in X-ray selected AGN

We explore the nature of the radio emission of X-ray selected AGN by combining deep radio (1.4GHz; 60micro-Jy) and X-ray data with multiwavelength (optical, mid-infrared) observations in the Extended Chandra Deep Field South (E-CDFS). The fraction of radio detected X-ray sources increases from 9% in the E-CDFS to 14% in the central region of this field, which has deeper X-ray coverage from the 1Ms CDFS. We find evidence that the radio emission of up to 60% of the hard X-ray/radio matched AGN is likely associated with star-formation in the host galaxy. Firstly, the mid-IR (24micron) properties of these sources are consistent with the infrared/radio correlation of starbursts. Secondly, most of them are found in galaxies with blue rest-frame optical colours (U-V), suggesting a young stellar population. On the contrary, X-ray/radio matched AGN which are not detected in the mid-infrared have red U-V colours suggesting their radio emission is associated with AGN activity. We also find no evidence for a population of heavily obscured radio-selected AGN that are not detected in X-rays. Finally, we do no confirm previous claims for a correlation between radio emission and X-ray obscuration. Assuming that the radio continuum measures star-formation, this finding is against models where the dust and gas clouds associated with circumnuclear starbursts are spherically blocking our view to the central engine.Comment: Accepted by A&

A Tale of Two Souths: microsatellite assessment of the role Portuguese Salmo salar populations play in Europe

Tese de mestrado, Biologia da Conservação, 2022, Universidade de Lisboa, Faculdade de CiênciasAtlantic salmon (Salmo salar L.) is an anadromous species with homing behaviour. Generally, individuals from this species are born in freshwater systems, migrate to feeding grounds in North Atlantic and return to their birthplace to reproduce. This reproductive isolation potentiates local adaptation. In recent years, Atlantic salmon populations in Europe have experienced great declines and are now classified as Vulnerable (VU). In Portugal, very little is known about this species, but this species is classified as Critically Endangered (CR), the highest threatened status. In this work, 14 microsatellite loci are used to assess population structure, migratory patterns and genetic diversity of 28 already identified and analysed populations (Gilbey et al., 2018), plus two additional populations, one from Galicia, Spain (Lerez River) and the other from Portuguese Minho basin (Mouro River). This is the first work to analyse Portuguese Atlantic salmon population’s genetics. The goal of the present study was to assess if the Portuguese populations were genetically distinguishable from other European populations. This work described a new Iberian genetic cluster, which is pointed out by several analysis (namely, STRUCTURE, PCoA and POPTREE2). This new group has a similar degree of differentiation from the Main European clusters as the Icelandic cluster that was described in previous works. Another important discovery described was the high relatedness among populations from Portugal and Galicia, when compared with the Asturian population, all located in the Iberian Peninsula. The genetic diversity analysis showed that the genetic uniqueness of each population is decreasing if compared to other works. The estimates of population effective size (Ne) indicate low Ne in most of the populations. It concludes that future genetic approaches to this species must consider this new Iberian cluster. On the other side, more studies must be done to fully understand the correlation between Iberian populations (in particular, northwestern coast populations and northern coast populations). It is also highlighted the necessity of management measures, for Portuguese populations since they are the most threatened populations

The Phoenix Deep Survey: spectroscopic catalog

The Phoenix Deep Survey is a multi-wavelength survey based on deep 1.4 GHz radio imaging, reaching well into the sub-100 microJy level. One of the aims of this survey is to characterize the sub-mJy radio population, exploring its nature and evolution. In this paper we present the catalog and results of the spectroscopic observations aimed at characterizing the optically ``bright'' (R<~ 21.5 mag) counterparts of faint radio sources. Out of 371 sources with redshift determination, 21% have absorption lines only, 11% show AGN signatures, 32% are star-forming galaxies, 34% show narrow emission lines that do not allow detailed spectral classification (due to poor signal-to-noise ratio and/or lack of diagnostic emission lines) and the remaining 2% are identified with stars. For the star-forming galaxies with a Balmer decrement measurement we find a median extinction of A(Ha)=1.9 mag, higher than that of optically selected samples. This is a result of the radio selection, which is not biased against dusty systems. Using the available spectroscopic information, we estimate the radio luminosity function of star-forming galaxies in two independent redshift bins at z~0.1 and 0.3 respectively. We find direct evidence for strong luminosity evolution of these systems consistent with L(1.4 GHz) ~ (1+z)^(2.7).Comment: 39 pages, 12 figures. References added, and minor changes to reflect published versio

The Phoenix Deep Survey: X-ray properties of faint radio sources

In this paper we use a 50ks XMM-Newton pointing overlapping with the Phoenix Deep Survey, a homogeneous radio survey reaching muJy sensitivities, to explore the X-ray properties and the evolution of star-forming galaxies. UV, optical and NIR photometry is available and is used to estimate photometric redshifts and spectral types for radio sources brighter than R=21.5mag (total of 82). Sources with R<21.5mag and spiral galaxy SEDs (34) are grouped into two redshift bins with a median of z=0.240 and 0.455 respectively. Stacking analysis for both the 0.5-2 and 2-8keV bands is performed on these subsamples. A high confidence level signal (>3.5sigma) is detected in the 0.5-2keV band corresponding to a mean flux of ~3e-16cgs for both subsamples. This flux translates to mean luminosities of ~5e40 and 1.5e41cgs for the z=0.240 and 0.455 subsamples respectively. Only a marginally significant signal (2.6sigma) is detected in the 2-8keV band for the z=0.455 subsample. We argue that the stacked signal above is dominated by star-formation. The mean L_X/L_B ratio and the mean L_X of the two subsamples are found to be higher than optically selected spirals and similar to starbursts. We also find that the mean L_X and L_1.4 of the faint radio sources studied here are consistent with the L_X-L_1.4 correlation of local star-forming galaxies. Moreover, the X-ray emissivity of sub-mJy sources to z~0.3 is found to be elevated compared to local HII galaxies. The observed increase is consistent with L_X evolution of the form (1+z)^3. Assuming that our sample is indeed dominated by starbursts this is direct evidence for evolution of such systems at X-ray wavelengths. Using an empirical L_X to SFR conversion we estimate a global SFR density at z~0.3 of \~0.029M_o/yr/Mpc in agreement with previous studies.Comment: 12 pages, 6 figures, accepted for publication in MNRA

The impact of online news’ context on the effects of display advertising : comparing the effects of positive and negative online news

The investment on digital media is a growing trend in today’s marketing environment, being display advertising a format usually adopted by marketers. Online news consumption is accompanying this growth and it is extremely hard to find online news articles without multiple elements that can influence readers' attention to other third-party content, such as display ads. While it is evident that advertisements exposed next to related articles is relevant and effective for advertisers. The real effect of the valence of the online news context - positive or negative - on consumers' attitudes and purchase intention towards the brand advertised is poorly known. An online survey was conducted in which two different versions of online news - positive and negative - about the CO2 emission in the automobile industry were created. One group of participants was exposed to the positive news and the other group to negative news. The groups were further analysed and compared for their differences on the dependent variables. The result indicates that the valence of the news context – positive or negative - has no significant impact on the attitude towards the ad, the attitude towards the brand and purchase intention. However, the attitude towards the ad positively affects the purchase intention. This research is relevant for advertisers, so they can redefine ad placement strategies, allocating display ads on relevant webpages and thus ensuring positive attitudes towards the website content. Finally, limitations and future research are presented.O investimento em media digital é uma tendência crescente no contexto de marketing atual, sendo o display advertising um formato geralmente adotado pelos marketers. O consumo de notícias online acompanha este crescimento e é cada vez mais difícil encontrar artigos de notícias online sem vários elementos periféricos que podem distrair a atenção dos leitores para outros conteúdos de terceiros, como os display ads. Embora seja evidente que a exposição de anúncios ao lado de artigos relacionados seja relevante e eficaz para os anunciantes, pouco se sabe sobre os efeitos da valência do contexto das notícias online nas atitudes dos consumidores e na intenção de compra em relação à marca anunciada. Foi realizado um questionário online, na qual foram criadas duas notícias online - positiva e negativa - sobre a emissão de CO2 na indústria automóvel. Um grupo foi exposto à notícia positiva e outro à notícia negativa, sendo posteriormente analisados e comparados para testar diferenças nas variáveis dependentes estudadas. O resultado indica que a valência do contexto das notícias - positiva ou negativa - não tem impacto significativo na atitude em relação ao anúncio, na atitude em relação à marca e na intenção de compra. Contudo, a atitude em relação ao anúncio afeta positivamente a intenção de compra. Esta pesquisa é relevante para anunciantes, para que possam redefinir as suas estratégias de posicionamento de anúncios em websites relevantes, a fim de garantir atitudes positivas em relação ao conteúdo do website. Finalmente, as limitações e pesquisas futuras são apresentadas