Inhomogeneities on the surface of 21 Lutetia, the asteroid target of the Rosetta mission

CONTEXT: In July 2010 the ESA spacecraft Rosetta will fly-by the main belt asteroid 21 Lutetia. Several observations of this asteroid have been so far performed, but its surface composition and nature are still a matter of debate. For long time Lutetia was supposed to have a metallic nature due to its high IRAS albedo. Later on it has been suggested to have a surface composition similar to primitive carbonaceous chondrite meteorites, while further observations proposed a possible genetic link with more evolved enstatite chondrite meteorites. AIMS: In order to give an important contribution in solving the conundrum of the nature of Lutetia, in November 2008 we performed visible spectroscopic observations of this asteroid at the Telescopio Nazionale Galileo (TNG, La Palma, Spain). METHODS: Thirteen visible spectra have been acquired at different rotational phases. RESULTS: We confirm the presence of a narrow spectral feature at about 0.47-0.48 micron already found by Lazzarin et al. (2009) on the spectra of Lutetia. We also find a spectral feature at about 0.6 micron, detected by Lazzarin et al. (2004) on one of their Lutetia's spectra. More importantly, our spectra exhibit different spectral slopes between 0.6 and 0.75 micron and, in particular, we found that up to 20% of the Lutetia surface could have flatter spectra. CONCLUSIONS: We detected a variation of the spectral slopes at different rotational phases that could be interpreted as possibly due to differences in the chemical/mineralogical composition, as well as to inhomogeneities of the structure of the Lutetia's surface (e.g., the presence of craters or albedo spots) in the southern hemisphere.Comment: 3 pages, 2 figures. Accepted for publication in Astronomy and Astrophysics. Updated on 25 March 2010

A comparative review on the well-studied GAT1 and the understudied BGT-1 in the brain

γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system (CNS). Its homeostasis is maintained by neuronal and glial GABA transporters (GATs). The four GATs identified in humans are GAT1 (SLC6A1), GAT2 (SLC6A13), GAT3 (SLC6A11), and betaine/GABA transporter-1 BGT-1 (SLC6A12) which are all members of the solute carrier 6 (SLC6) family of sodium-dependent transporters. While GAT1 has been investigated extensively, the other GABA transporters are less studied and their role in CNS is not clearly defined. Altered GABAergic neurotransmission is involved in different diseases, but the importance of the different transporters remained understudied and limits drug targeting. In this review, the well-studied GABA transporter GAT1 is compared with the less-studied BGT-1 with the aim to leverage the knowledge on GAT1 to shed new light on the open questions concerning BGT-1. The most recent knowledge on transporter structure, functions, expression, and localization is discussed along with their specific role as drug targets for neurological and neurodegenerative disorders. We review and discuss data on the binding sites for Na+, Cl-, substrates, and inhibitors by building on the recent cryo-EM structure of GAT1 to highlight specific molecular determinants of transporter functions. The role of the two proteins in GABA homeostasis is investigated by looking at the transport coupling mechanism, as well as structural and kinetic transport models. Furthermore, we review information on selective inhibitors together with the pharmacophore hypothesis of transporter substrates

Matemática Inclusiva: Ensinando Matrizes a Deficientes Visuais

Nos últimos anos, a inclusão de portadores de deficiência no sistema educacional brasileiro vem sendo amplamente discutida. Entre as dificuldades desse processo, podem ser citados a estrutura inadequada das escolas e o despreparo dos professores. Nesse sentido, esforços individuais dos docentes são necessários na busca por estratégias pedagógicas que minimizem tais dificuldades. Neste artigo, temos por objetivo apresentar um estudo de caso em que o conteúdo de matrizes do Ensino Médio foi trabalhado com um aluno portador de deficiência visual total. Para este trabalho, fizemos uso de um  modelo de material concreto de baixo custo, que foi desenvolvido em conjunto com o Núcleo de Apoio às Pessoas com Necessidades Especiais (NAPNE) do Instituto Federal Farroupilha, campus Santo Augusto – RS. Serão apresentadas algumas técnicas diferenciadas usadas pelo aluno no decorrer do processo de aprendizagem e abordadas algumas posturas que o professor pode adotar para favorecer esse processo

The Breast-Q assessment: Sant'Andrea experience

Despite in the last 20 years breast surgery has become less mutilating, mastectomy is indicated in approximately 30% of cases, not only for large invasive carcinoma, but also for multicentric tumors and intraductal diffuse carcinomas. The nipple loss is experienced by the patients like a mutilation; we achieved a significant improvement of the aesthetic result performing Nipplesparing mastectomy (NSM), joined with reconstruction techniques. This approach has a positive impact on psychology and quality of life (QOL) of breast cancer patients. To evaluate these important aspects, we retrospectively applied the BREAST-Q questioner to 101 patients underwent a NSM. BREAST-Q is an instrument designed by the Evelyn H. Lauder Breast Center, MSKCC (NY), to assess outcomes among women undergoing different types of breast surgery: we chose reconstruction module that is comprised of two domains: patient satisfaction and QOL. There are six subthemes (physical, psychosocial and sexual well-being patient, satisfaction with breast, satisfaction with overall outcomes and satisfaction with care). From December 2003 to September 2013 we performed 157 NSMs with immediate breast reconstruction on a court of 117 patients. Selection criteria included women with preoperative diagnosis of breast cancer, tumor at least 1 cm from nipple- areola complex (NAC) without nipple discharge or NAC retraction. The median follow-up was 40 months with an age range between 19 and 72 y. We recorded 2 deaths for breast cancer, with a overall survival of 97% and a rate of local recurrence of 8.5% (10 cases). Our follow-up program included medical interview, examination of routine clinical and imaging findings, and collecting information by the BREAST-Q survey. 101 patients agreed the questioner. Our results confirm that BREAST-Q is an useful to evaluate QOL and obtain a more tailored surgery. Patients are very interested to a chance of explaining their point of view or suggesting improvements or propose grievances to the surgical equipe. This is a preliminary report, even if findings are tell now encouraging: the definitive results need greater casemix and longer follow-up. We are already satisfied about the contribution of our Breast Unit.Despite in the last 20 years breast surgery has become less mutilating, mastectomy is indicated in approximately 30% of cases, not only for large invasive carcinoma, but also for multicentric tumors and intraductal diffuse carcinomas. The nipple loss is experienced by the patients like a mutilation; we achieved a significant improvement of the aesthetic result performing Nipplesparing mastectomy (NSM), joined with reconstruction techniques. This approach has a positive impact on psychology and quality of life (QOL) of breast cancer patients. To evaluate these important aspects, we retrospectively applied the BREAST-Q questioner to 101 patients underwent a NSM. BREAST-Q is an instrument designed by the Evelyn H. Lauder Breast Center, MSKCC (NY), to assess outcomes among women undergoing different types of breast surgery: we chose reconstruction module that is comprised of two domains: patient satisfaction and QOL. There are six subthemes (physical, psychosocial and sexual well-being patient, satisfaction with breast, satisfaction with overall outcomes and satisfaction with care). From December 2003 to September 2013 we performed 157 NSMs with immediate breast reconstruction on a court of 117 patients. Selection criteria included women with preoperative diagnosis of breast cancer, tumor at least 1 cm from nipple- areola complex (NAC) without nipple discharge or NAC retraction. The median follow-up was 40 months with an age range between 19 and 72 y. We recorded 2 deaths for breast cancer, with a overall survival of 97% and a rate of local recurrence of 8.5% (10 cases). Our follow-up program included medical interview, examination of routine clinical and imaging findings, and collecting information by the BREAST-Q survey. 101 patients agreed the questioner. Our results confirm that BREAST-Q is an useful to evaluate QOL and obtain a more tailored surgery. Patients are very interested to a chance of explaining their point of view or suggesting improvements or propose grievances to the surgical equipe. This is a preliminary report, even if findings are tell now encouraging: the definitive results need greater casemix and longer follow-up. We are already satisfied about the contribution of our Breast Unit

Physical properties of ESA Rosetta target asteroid (21) Lutetia: Shape and flyby geometry

Aims. We determine the physical properties (spin state and shape) of asteroid (21) Lutetia, target of the ESA Rosetta mission, to help in preparing for observations during the flyby on 2010 July 10 by predicting the orientation of Lutetia as seen from Rosetta. Methods. We use our novel KOALA inversion algorithm to determine the physical properties of asteroids from a combination of optical lightcurves, disk-resolved images, and stellar occultations, although the latter are not available for (21) Lutetia. Results. We find the spin axis of (21) Lutetia to lie within 5 degrees of ({\lambda} = 52 deg., {\beta} = -6 deg.) in Ecliptic J2000 reference frame (equatorial {\alpha} = 52 deg., {\delta} = +12 deg.), and determine an improved sidereal period of 8.168 270 \pm 0.000 001 h. This pole solution implies the southern hemisphere of Lutetia will be in "seasonal" shadow at the time of the flyby. The apparent cross-section of Lutetia is triangular as seen "pole-on" and more rectangular as seen "equator-on". The best-fit model suggests the presence of several concavities. The largest of these is close to the north pole and may be associated with large impacts.Comment: 17 pages, 5 figures, 3 tables, submitted to Astronomy and Astrophysic

The NEOShield-2 EU project: The Italian contribution

The NEOShield-2 (2015-2017) project has been recently approved by the European Commission in the framework of the Horizon 2020 programme with the aim i) to study specific technologies and instruments to conduct close approach missions to NEOs or to undertake mitigation demonstration, and ii) to acquire in-depth information of physical properties of the population of small NEOs (50-300 m), in order to design mitigation missions and assess the consequences of an impact on Earth. The Italian scientific community is widely involved in this project

Physical Investigation of the Potentially Hazardous Asteroid (144898) 2004 VD17

In this paper we present the observational campaign carried out at ESO NTT and VLT in April and May 2006 to investigate the nature and the structure of the Near Earth Object (144898) 2004 VD17. In spite of a great quantity of dynamical information, according to which it will have a close approach with the Earth in the next century, the physical properties of this asteroid are largely unknown. We performed visible and near--infrared photometry and spectroscopy, as well as polarimetric observations. Polarimetric and spectroscopic data allowed us to classify 2004 VD17 as an E-type asteroid. A good agreement was also found with the spectrum of the aubrite meteorite Mayo Belwa. On the basis of the polarimetric albedo (p_v=0.45) and of photometric data, we estimated a diameter of about 320 m and a rotational period of about 2 hours. The analysis of the results obtained by our complete survey have shown that (144898) 2004 VD17 is a peculiar NEO, since it is close to the breakup limits for fast rotator asteroids, as defined by Pravec and Harris (2000). These results suggest that a more robust structure must be expected, as a fractured monolith or a rubble pile in a "strength regime" (Holsapple 2002).Comment: 32 pages, 7 figure, paper accepted for publication in Icaru

Photometric survey of 67 near-Earth objects

Context. The near-Earth object (NEO) population is a window into the original conditions of the protosolar nebula, and has the potential to provide a key pathway for the delivery of water and organics to the early Earth. In addition to delivering the crucial ingredients for life, NEOs can pose a serious hazard to humanity since they can impact the Earth. To properly quantify the impact risk, physical properties of the NEO population need to be studied. Unfortunately, NEOs have a great variation in terms of mitigation-relevant quantities (size, albedo, composition, etc.) and less than 15% of them have been characterized to date. Aims. There is an urgent need to undertake a comprehensive characterization of smaller NEOs (D < 300 m) given that there are many more of them than larger objects; their small sizes make them intrinsically fainter and therefore harder to study. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Community in the framework of the Horizon 2020 program, is therefore to retrieve physical properties of a wide number of NEOs in order to design impact mitigation missions and assess the consequences of an impact on Earth. Methods. We carried out visible photometry of NEOs, making use of the DOLORES instrument at the Telescopio Nazionale Galileo (TNG, La Palma, Spain) in order to derive visible color indexes and the taxonomic classification for each target in our sample. Results. We attributed for the first time the taxonomical complex of 67 objects obtained during the first year of the project. While the majority of our sample belong to the S-complex, carbonaceous C-complex NEOs deserve particular attention. These NEOs can be located in orbits that are challenging from a mitigation point of view, with high inclination and low minimum orbit intersection distance (MOID). In addition, the lack of carbonaceous material we see in the small NEO population might not be due to an observational bias alone

Space Weathering on Near-Earth Objects investigated by neutral-particle detection

The ion-sputtering (IS) process is active in many planetary environments in the Solar System where plasma precipitates directly on the surface (for instance, Mercury, Moon, Europa). In particular, solar-wind sputtering is one of the most important agents for the surface erosion of a Near-Earth Object (NEO), acting together with other surface release processes, such as Photon Stimulated Desorption (PSD), Thermal Desorption (TD) and Micrometeoroid Impact Vaporization (MIV). The energy distribution of the IS-released neutrals peaks at a few eVs and extends up to hundreds of eVs. Since all other release processes produce particles of lower energies, the presence of neutral atoms in the energy range above 10 eV and below a few keVs (Sputtered High-Energy Atoms - SHEA) identifies the IS process. SHEA easily escape from the NEO, due to NEO's extremely weak gravity. Detection and analysis of SHEA will give important information on surface-loss processes as well as on surface elemental composition. The investigation of the active release processes, as a function of the external conditions and the NEO surface properties, is crucial for obtaining a clear view of the body's present loss rate as well as for getting clues on its evolution, which depends significantly on space weather. In this work, an attempt to analyze the processes that take place on the surface of these small airless bodies, as a result of their exposure to the space environment, has been realized. For this reason a new space weathering model (Space Weathering on NEO - SPAWN), is presented. Moreover, an instrument concept of a neutral-particle analyzer specifically designed for the measurement of neutral density and the detection of SHEA from a NEO is proposedComment: 36 page