The evolution of galaxy sizes

We present a study of galaxy sizes in the local Universe as a function of galaxy environment, comparing clusters and the general field. Galaxies with radii and masses comparable to high-z massive and compact galaxies represent 4.4% of all galaxies more massive than 3 X 10^{10} M_sun in the field. Such galaxies are 3 times more frequent in clusters than in the field. Most of them are early-type galaxies with intermediate to old stellar populations. There is a trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. We show the relation between size and luminosity-weighted age for galaxies of different stellar masses and in different environments. We compare with high-z data to quantify the evolution of galaxy sizes. We find that, once the progenitor bias due to the relation between galaxy size and stellar age is removed, the average amount of size evolution of individual galaxies between high- and low-z is mild, of the order of a factor 1.6.Comment: to appear in the proceedings of the IAU S295: The intriguing life of massive galaxies, editors D. Thomas, A. Pasquali & I. Ferrera

The importance of the local density in shaping the galaxy stellar mass functions

Exploiting the capabilities of four different surveys --- the Padova-Millennium Galaxy and Group Catalogue (PM2GC), the WIde-field Nearby Galaxy-cluster Survey (WINGS), the IMACS Cluster Building Survey (ICBS) and the ESO Distant Cluster Survey (EDisCS) --- we analyze the galaxy stellar mass distribution as a function of local density in mass-limited samples, in the field and in clusters from low (z>0.04) to high (z<0.8) redshift. We find that at all redshifts and in all environments, local density plays a role in shaping the mass distribution. In the field, it regulates the shape of the mass function at any mass above the mass limits. In clusters, it seems to be important only at low masses (log M_ast/M_sun <10.1 in WINGS and log M_ast/M_sun < 10.4 in EDisCS), otherwise it seems not to influence the mass distribution. Putting together our results with those of Calvi et al. and Vulcani et al. for the global environment, we argue that at least at $z\leq 0.8$ local density is more important than global environment in determining the galaxy stellar mass distribution, suggesting that galaxy properties are not much dependent of halo mass, but do depend on local scale processes.Comment: MNRAS accepted, in pres

A adoção de sistemas agroflorestais na agricultura familiar de Medicilândia, Pará.

Sistemas agroflorestais (SAF) são uma alternativa às práticas agrícolas convencionais e de uso do solo ainda pouco utilizados por agricultores familiares. Incentivar a implantação desses sistemas é relevante devido as preocupações com a conservação da biodiversidade e as mudanças climáticas globais. O cacaueiro é uma cultura propícia à implantação em SAF devido à necessidade de sombreamento das lavouras, sendo o município de Medicilândia-PA, um dos principais pólos cacaueiros do país. Objetivando entender os fatores contribuem é/ou limitam a utilização dos SAF, foram aplicados questionários a 73 famílias agricultoras. Os principais fatores que determinam a adoção de SAF pelos agricultores estão relacionados à ordem econômica e produtiva, sendo a existência de mercado e o aumento da renda os fatores que se destacam para essa adoção. Em oposição, a principal limitação refere-se à insuficiência e baixa qualidade dos serviços de assistência técnica pública oferecida, afetando, diretamente, a produção dos si•s•temas uma vez que a gestão de SAF sem acompanhamento técnico poderá reduzir, consideravelmente, a produtividade da lavoura

The use of ciclosporin in paediatric inflammatory bowel disease: an Italian experience

Aim: To asses the efficacy and safety of ciclosporin in a paediatric population with inflammatory bowel disease. Patients and methods: Twenty-three Italian children treated with ciclosporin were studied retrospectively. The indications for treatment were severe unresponsive colitis, chronic active colitis or severe fistulizing Crohn's disease. The treatment duration, follow-up and causes of drug discontinuation were assessed. Results: Sixteen patients were treated intravenously for a mean time of 10 +/- 7 days (1-24 days) and 19 orally for a mean time of 133 days (17-660 days). The mean follow-up of all patients was 13.2 months. Ciclosporin was totally ineffective, being discontinued for surgery, in nine of 23 patients (39%); it was discontinued for partial response in three patients (13%). During treatment, clinical remission was achieved in eight children (35%) and maintained after drug withdrawal in four (17%). In severe unresponsive colitis, urgent colectomy was avoided in 12 (85%) of 14 patients who tolerated the drug. Side-effects appeared in six of 23 patients (26%), and three (13%) required ciclosporin to be discontinued due to neurotoxicity. Conclusions: Ciclosporin shows disappointing long-term results in the treatment of refractory inflammatory bowel disease, but can play an important role in preventing urgent surgery in unresponsive severe colitis. Severe side-effects can occur

Differentiating Vogt-Koyanagi-Harada syndrome from recurrent optic neuritis: a case report and review of the literature concerning Hispanic patients

Abstract Background First recognized at the beginning of twentieth century and named after three authors who independently described some affected patients, Vogt-Koyanagi-Harada syndrome is a rare multisystemic autoimmune disease targeting melanin-containing tissues of the eye, meninges, inner ear and skin. It predominantly affects Asian people, but also people with darker skin pigmentation such as Native Americans and Hispanics (Mestizos), whose ancestors moved from Asia across the Bering strait to North America and further down to Central and South America. Heterogenous presentation is observed, especially among different ethnic groups. Here we describe the case of an Hispanic South American patient presenting with multiple visual relapses and thus mimicking recurrent optic neuritis; we provide insights into the differential diagnosis and a brief review of the literature concerning the epidemiology of Vogt-Koyanagi-Harada syndrome in Hispanic patients compared with other ethnic groups. Case presentation A 34-year-old Ecuadorian woman presented over years with multiple relapses involving the visual system. She was investigated in both neurologic and ophthalmic clinical settings. Brain Magnetic Resonance Imaging, cerebrospinal fluid examination, Spectral Domain Optical Coherence Tomography and Fluorescein Angiography were performed. She was misdiagnosed first as an optic neuritis pointing to a demyelinating disorder, then as a posterior scleritis. Due to the protean manifestations of Vogt-Koyanagi-Harada syndrome and the incomplete clinical presentation at the beginning, the right diagnosis was made only at a later disease stage using retrospective criteria. Conclusions Hispanic patients often present without extraocular symptoms in early phases of the disease and they have globally lower rates of intertegumentary signs compared to Asian patients. The diagnosis of a multisystemic disease such as Vogt-Koyanagi-Harada syndrome is a challenge involving specialists operating in different medical fields; especially in urban multiethnic populations, rare etiologies of common symptoms have to be taken into account when performing a differential diagnosis

User-centred design of flexible hypermedia for a mobile guide: Reflections on the hyperaudio experience

A user-centred design approach involves end-users from the very beginning. Considering users at the early stages compels designers to think in terms of utility and usability and helps develop the system on what is actually needed. This paper discusses the case of HyperAudio, a context-sensitive adaptive and mobile guide to museums developed in the late 90s. User requirements were collected via a survey to understand visitors’ profiles and visit styles in Natural Science museums. The knowledge acquired supported the specification of system requirements, helping defining user model, data structure and adaptive behaviour of the system. User requirements guided the design decisions on what could be implemented by using simple adaptable triggers and what instead needed more sophisticated adaptive techniques, a fundamental choice when all the computation must be done on a PDA. Graphical and interactive environments for developing and testing complex adaptive systems are discussed as a further step towards an iterative design that considers the user interaction a central point. The paper discusses how such an environment allows designers and developers to experiment with different system’s behaviours and to widely test it under realistic conditions by simulation of the actual context evolving over time. The understanding gained in HyperAudio is then considered in the perspective of the developments that followed that first experience: our findings seem still valid despite the passed time

Measurement and Interpretation of Fermion-Pair Production at LEP energies above the Z Resonance

This paper presents DELPHI measurements and interpretations of cross-sections, forward-backward asymmetries, and angular distributions, for the e+e- -> ffbar process for centre-of-mass energies above the Z resonance, from sqrt(s) ~ 130 - 207 GeV at the LEP collider. The measurements are consistent with the predictions of the Standard Model and are used to study a variety of models including the S-Matrix ansatz for e+e- -> ffbar scattering and several models which include physics beyond the Standard Model: the exchange of Z' bosons, contact interactions between fermions, the exchange of gravitons in large extra dimensions and the exchange of sneutrino in R-parity violating supersymmetry.Comment: 79 pages, 16 figures, Accepted by Eur. Phys. J.

Study of Leading Hadrons in Gluon and Quark Fragmentation

The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.