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Both freshwater floodplain (várzeas and igapós) forests and brackish-saline mangroves are abundant and well-described ecosystems in Brazil.

The hair mineralogram is a complementary multielement analysis that provides information to aid in the diagnosis of a patient’s health status; however, aesthetic treatments can affect the analysis results. This research aimed to identify standard patterns among mineralogram results and some variables, such as gender and the use of aesthetical treatments that can point out differences and causes of variation in elemental concentrations in hair. For this purpose, 151 hair samples were obtained from volunteers and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). This work is pilot research, part of a project to encourage girls to the STEM area, called “Girls in Science”, with financial support from the Brazilian Government. Mineralogram results were compared through statistical analysis. The results of natural hair indicate significant differences (p

Atmospheric pollution has been considered one of the most important topics in environmental science once it can be related to the incidence of respiratory diseases, climate change, and others. Knowing the composition of this complex and variable mixture of gases and particulate matter is crucial to understand the damages it causes, help establish limit levels, reduce emissions, and mitigate risks. In this work, the current scenario of the legislation and guideline values for indoor and outdoor atmospheric parameters will be reviewed, focusing on the inorganic and organic compositions of particulate matter and on biomonitoring. Considering the concentration level of the contaminants in air and the physical aspects (meteorological conditions) involved in the dispersion of these contaminants, different approaches for air sampling and analysis have been developed in recent years. Finally, this review presents the importance of data analysis, whose main objective is to transform analytical results into reliable information about the significance of anthropic activities in air pollution and its possible sources. This information is a useful tool to help the government implement actions against atmospheric air pollution.

Investigation were carried out targeting distribution and source apportioning of hydrocarbons in surface sediments from shallow to deep waters in the Campos Basin, one of the most important oil-producing provinces in Brazil. The observed levels of aliphatic (≤ 124 μg g−1) and polycyclic aromatic hydrocarbons (PAHs ≤ 599 ng g−1) are lower than those considered relevant for environmental risk to the benthic habitats. Higher median concentrations of aliphatic hydrocarbons (8.49 μg g−1) and PAHs (84.8 ng g−1) in the middle slope sediments (700–1000-m water depths) showed the influence of hydrodynamics upon hydrocarbon accumulation in the sediments. Diagnostic ratios and conventional statistical analysis applied to hydrocarbon data produced insufficient information on the contribution of different sources. These traditional approaches do not consider the potential changes affecting source assignment and therefore cannot deal with the uncertainties. The fuzzy logic applied as an alternative method for data treatment successfully incorporated the uncertainties in the differentiation between petrogenic and pyrolytic sources, including those due to degradation. Moreover, by using fuzzy logic, it was possible to identify that water circulation patterns, mass transport, deposition, and degradation processes are more relevant factors in determining hydrocarbon composition than source proximity.

The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 degrees C and (ii) a freeze-thaw cycle (FTC) alternating between -20 and 4 degrees C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes. Funding Agencies|Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)National Council for Scientific and Technological Development (CNPq); Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Carlos Chagas Filho Foundation for Research Support of the State of Rio de Janeiro (FAPERJ); Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CAPES; KAUSTKing Abdullah University of Science & Technology [BAS/1/1096-01-01]

Context.The Metis coronagraph on board Solar Orbiter offers a new view of coronal mass ejections (CMEs), observing them for the first time with simultaneous images acquired with a broad-band filter in the visible-light interval and with a narrow-band filter around the H ILy-αline at 121.567 nm, the so-called Metis UV channel.Aims.We show the first Metis observations of a CME, obtained on 16 and 17 January 2021. The event was also observed by the EUI/FSI imager on board Solar Orbiter, as well as by other space-based coronagraphs, such as STEREO-A/COR2 and SOHO/LASCO/C2, whose images are combined here with Metis data.Methods.Different images are analysed here to reconstruct the 3D orientation of the expanding CME flux rope using the graduated cylindrical shell model. This also allows us to identify the possible location of the source region. Measurements of the CME kinematics allow us to quantify the expected Doppler dimming in the Ly-αchannel.Results.Observations show that most CME features seen in the visible-light images are also seen in the Ly-αimages, although some features in the latter channel appear more structured than their visible-light counterparts. We estimated the expansion velocity of this event to be below 140 km s−1. Hence, these observations can be understood by assuming that Doppler dimming effects do not strongly reduce the Ly-αemission from the CME. These velocities are comparable with or smaller than the radial velocities inferred from the same data in a similar coronal structure on the east side of the Sun.Conclusions.The first observations by Metis of a CME demonstrate the capability of the instrument to provide valuable and novel information on the structure and dynamics of these coronal events. Considering also its diagnostics capabilities regarding the conditions of the ambient corona, Metis promises to significantly advance our knowledge of such phenomena.

The aim of this research was the replacement of conventional sample extraction techniques for polycyclic aromatic hydrocarbons (PAH) in tissue samples for a reliable, fast and ecofriendly procedure. The method was developed using a pressurized solvent extraction method and assessing two different standard reference materials (fish and mussel) and freeze-dried and fortified sardine samples (Sardinella sp.). Five different extraction procedures were evaluated and the best performance comprised 1 g of lyophilized tissue, 5 g of deactivated (5%) silica, a dichloromethane:methanol (4:1 v/v) mixture, a temperature of 80 °C, three cycles, 10 min of static time and 90 s of purge time. The method selected following these tests was further validated through the analysis of nine replicates of the National Institute of Standard and Technology (NIST) reference material No. 2976, resulting in an effective recovery of 83 ± 14%. The means and uncertainties attained for each PAH were equivalent to those of the reference material, corroborating the reliability of the developed method. A shorter processing time, less use of solvents and reagents and lower extract manipulation produced an effective method aligned with green-chemistry guidelines.

The concentrations of 37 polycyclic aromatic hydrocarbons (PAHs) and their potential risk to human health were determined in fifty sardine muscle (Sardinella brasiliensis) samples collected along the southern Brazilian shelf. Parental and alkylated PAHs were identified and quantified using a pressurized liquid extraction with in-cell purification method and gas chromatography–mass spectrometry identification and quantification. The concentrations of Σ37 PAHs in muscle ranged between 6.02 and 4074 μg kg−1 wet weight, which are comparable to levels reported for commercially important fish worldwide. The most abundant compounds were pyrene and fluoranthene, which originate from both petrogenic and pyrolytic hydrocarbon inputs. In only 4% of the samples the benzo[a] pyrene equivalent concentration was above the threshold of 6 μg kg−1 suggested for safe fish consumption in Brazil. These findings will serve as baseline data for monitoring the quality of sardines consumed in the country and for studying fish populations.

Aliphatic and polycyclic aromatic hydrocarbons (PAHs) were quantified in harbors sediments from SE Brazil. The aims were to (i) compare harbors with distinct sizes and under the influence of different environmental pressures with respect to the sources and level of hydrocarbon contamination and (ii) evaluate the potential of adverse biological effects of sediment contamination by PAHs, based on sediment quality guidelines and toxicity equivalence quotient. The concentrations of total aliphatics (39.9 μg g − 1 ; 22.9–113 μg g − 1 ) and total PAHs (727 ng g − 1 ; 366–1760 ng g − 1 ) varied according to the size of and urban development around each harbor. Mixed contamination by petrogenic and pyrolytic hydrocarbons, and input of biogenic compounds, indicated the influence of both harbor activities and a myriad of urban, industrial and atmospheric inputs. The quality of sediment poses a risk to benthic biological communities, and, if dredged, this material may cause environmental damage in the waste disposal area.

A method for the determination of polychlorinated biphenyls (PCBs) in water from urban rivers was implemented and validated. Extractions of dissolved and particulate PCBs were performed using solid-phase extraction and a pressurized solvent extraction system, respectively, and the analytes were identified and quantified by gas chromatography with tandem mass spectrometry in selected reaction monitoring mode with no further purification. The method was successfully developed for the determination of 41 PCBs with two precursor-product confirmations for each analyte. Low method detection limits (0.06–0.50 ng L−1) and good precision (≤ 20%; n = 8) were obtained, as well a linear response of the calibration curve ranging from 1.0 to 50 ng L−1. Method performance for real samples was tested with water collected weekly in triplicate during April 2018 from a eutrophic river in the city of Rio de Janeiro. The total (dissolved + particulate) PCB concentrations ranged from 2.17 to 5.29 ng L−1, above the threshold for river water quality standards in Brazil.

Polycyclic aromatic (46 PAHs) and aliphatic hydrocarbons (C12−C40) were studied in atmospheric particulate matter sampled in Rio de Janeiro Metropolitan Area (RJMA). In total, 236 samples from six different sites were collected simultaneously and weekly over 1 year (January–December 2011) allowing a robust atmospheric characterization of fine particulate matter (PM2.5). Hydrocarbon concentration was in general low compared to previous studies in the area (PAHs range 0.25–19.3 ng m−3), possibly due to changes in fuel composition over time. Precipitation is the main meteorological parameter that rules particulate and hydrocarbon concentration, modifying PAH typology by scavenging. Aliphatic and aromatic diagnostic ratios gave indications conflicting with combustion features. However, ratios showed differences among sites. Principal component analysis (PCA) associated to multiple linear regressions (MLR) allowed quantitative estimate of sources and effectively indicated vehicular emission as the main hydrocarbon source in the atmospheric particulate matter.

RESUMO Lipidios biomarcadores [acidos graxos (FA), esterois e alcoois], isotopos estaveis (δ13C e δ15N), aminoacidos totais hidrolisaveis (THAA) e carbono orgânico total (COT) foram quantificados em 215 amostras de sedimentos superficiais coletadas em dois periodos (seco e chuvoso de 2008/2009) entre 25 e 3.000 m de profundidade ao longo de nove transectos transversais a margem continental. Tambem foram analisadas amostras de sedimento superficial em dois cânions (Grussai e Almirante Câmara) para os mesmos indicadores, com excecao de isotopos. O objetivo foi investigar os processos relacionados com a origem, transporte e acumulo de materia orgânica (MO) na regiao de estudo. Nas amostras dos transectos, a composicao de lipidios biomarcadores sugeriu a predominância de materia orgânica derivada de produtores primarios e secundarios na coluna d’agua, mas foram observados gradientes espaciais significativos da qualidade e quantidade da materia orgânica sedimentar. As menores concentracoes de lipidios, com predominância de compostos labeis, foram medidas na plataforma continental (< 150 m), exceto nas areas influenciadas por ressurgencia costeira e/ou por intrusao subsuperficial de aguas mais ricas em nutrientes, onde maiores concentracoes de carbono orgânico total e lipidios foram obtidas. O talude superior e medio (400 a 1.300 m) tambem exibiram elevadas concentracoes de carbono orgânico total e lipidios, mas com uma maior influencia de lipidios ja alterados pela atividade bacteriana. Isto sugeriu que ha exportacao de materiais de areas rasas para o talude, possivelmente devido a acao de vortices e meandros da Corrente do Brasil e por correntes de fundo. No talude inferior (1.900 a 3.000 m), apenas os compostos mais recalcitrantes foram medidos acima dos limites de deteccao. Em relacao aos cânions, a distribuicao dos lipidios biomarcadores sugeriram que eles sao locais efetivos de acumulo e transporte de materia orgânica labil para porcoes mais profundas da margem continental. No geral, os isotopos e os aminoacidos totais hidrolisaveis proveram informacoes que foram consistentes e corroboraram as observacoes feitas com base nos lipidios biomarcadores.

The aim of this work was to test the efficiency of statistical methods as compared to the traditional diagnostic ratios to improve hydrocarbon source identification in sediments subjected to multiple inputs. Hydrocarbon determination in Guanabara Bay sediments pointed out high degradation and ubiquitous petrogenic pollution through the presence of high unresolved complex mixture. Polycyclic aromatic hydrocarbon (PAHs) ratios suggested pervasive contamination derived from combustion in all sediments and failed discriminating samples despite the specificity of sources in different sampling sites. Principal component analysis (PCA) effectively distinguished the petrogenic imprint superimposed to the ubiquitous combustion contamination, since this technique reduces the influence of PAHs distribution which is common to all samples. PCA associated to multivariate linear regression (MLR) allowed a quantitative assessment of sources confirming predominance of the pervasive contaminant component superimposed to a generalized petrogenic imprint. The pervasive component derives from combustion contributions as well as from differential PAHs degradation.

Polycyclic aromatic (46 PAHs) and aliphatic hydrocarbons (C12-C40) were studied in atmospheric particulate matter sampled in Rio de Janeiro Metropolitan Area (RJMA). In total, 236 samples from six different sites were collected simultaneously and weekly over 1 year (January-December 2011) allowing a robust atmospheric characterization of fine particulate matter (PM2.5). Hydrocarbon concentration was in general low compared to previous studies in the area (PAHs range 0.25-19.3 ng m(-3)), possibly due to changes in fuel composition over time. Precipitation is the main meteorological parameter that rules particulate and hydrocarbon concentration, modifying PAH typology by scavenging. Aliphatic and aromatic diagnostic ratios gave indications conflicting with combustion features. However, ratios showed differences among sites. Principal component analysis (PCA) associated to multiple linear regressions (MLR) allowed quantitative estimate of sources and effectively indicated vehicular emission as the main hydrocarbon source in the atmospheric particulate matter.

Aliphatic (n-C12-n-C40, unresolved complex mixture, resolved peaks) and aromatic hydrocarbons (46 PAH) were investigated in suspended particulate matter (SPM) sampled over eleven months in six of the major rivers and two channels of the Guanabara Bay Basin. PAH flow rates of the most contaminated rivers, the contribution to the PAH sediment load of the receiving bay, and the main sources of hydrocarbons were determined. PAH (38) ranged from 28 ng L(-1) to 11,514 ng L(-1). Hydrocarbon typology and statistical evaluation demonstrated contribution of distinct sources in different regions and allowed quantification of these contributions. Total flow rate for the five major rivers amounts to 3 t year(-1) and responds for 30% of the total PAH annual input into the northern area of the Guanabara Bay. For the first time PAH mass deposited in the bay sediments has been estimated and shall serve as base for decision making and source abatement.

The TOCAMM (TOrino CAgliari Measuring Machine) project undertaken jointly between Torino and Cagliari Astronomical Observatories aimed to convert the old measuring machine ASCORECORD into an automatic and impersonal one. This program is intended to contribute to the link of the HIPPARCOS Catalogue to the ICRS through the determination of precise position of optical counterparts of 80 extragalactic radiosources taken from the IERS list and to investigate the astrometric accuracy of the Guide Star Catalog (version 1 and 2). The calibration test phase, carried out first at the Astronomical Observatory of Torino and after at Cagliari Observatory, where the machine has been now installed, indicate that the available positional accuracy is about 0.5 microns in both x and y coordinates.

Lists of CCD photometric standard stars in the BVRc system of Johnson and Cousins are presented for two regions of importance in studies of galactic structure and kinematics: one at the North galactic pole (NGP) (bII =8 5), and a second on the galactic equator toward the anti{center (lII = 133:2, bII = 1:6). Precision of both magnitudes and colors is better than 0.05 mag down to V =1 8 :5 for the NGP sample, and to V =1 8 : 0f or the set on the galactic plane. Accuracy is also better than 0:05 mag, as shown by comparison to standard (intrinsic) color-color diagrams. These sequences should full the needs for faint refer- ence stars in the photometric calibration of old and new large-area surveys using wide-angle photographic plates. This is the case, for example, of the new multicolor sur- veys of the Palomar Observatory, which uses the Oschin Schmidt telescope, and the Second Generation Southern Sky Survey, which utilizes UK Schmidt of the Anglo Australian Observatory in Siding Spring.

Trapezia systems are defined as multiple stars, having three or more components with separation ratios in the range 0.3 to 3. The revival of interest in Trapezia is due to their potential astrophysical significance, as they could originate from a single protostar and be in an expansion stage because of their possible positive energy (see, for example, Bernacca 1988 and references therein). Further decisive advancements in understanding the nature of these systems require data for establishing a list of physically bound systems as well as for the systematic study of their kinematics and energetics. In the present progress report we test three representative cases with the combined exploitation of astrometric, photometric, and spectroscopic data.

We present optical positions in the improved IAU System at the standard epoch J2000.0 of some extragalactic radio sources obtained at Torino Astronomical Observatory. The primary reference stars are taken from the Carlsberg Automatic Meridian Catalogues 1 and 2 (CAMC).

The combination of more than two beams is appealing from the scientific standpoint due to the increased sampling of the spatial frequency plane. Each telescope beam is affected by an independent piston noise, which must be measured and corrected in order to achieve stable observing conditions on the science targets. We discuss fringe sensor implementation concepts, taking into account aspects evidenced from the current experience at VLTI.

Faint surveys of accurate colors and proper motions are fundamental for studying the physical and kinematical properties of the stellar populations in the Galaxy. A program designed to address such issues has been initiated on selected fields utilizing prototype material from the GSC-II project (see McLean et al. in this volume, p. 431). Photographic photometry V, B–V, V–Rc, is derived down to V = 18.5 with a precision of about 0.1 mag, together with absolute proper motions to σμ ≃ 3 mas/yr.

BL Lacertae has been the target of four observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we present UBVRI light curves obtained by theWEBT from 1994 to 2002, including the last, extended BL Lac 2001 campaign. A total of about 7500 optical observations performed by 31 telescopes from Japan to Mexico have been collected, to be added to the ∼15 600 observations of the BL Lac Campaign 2000. All these data allow one to follow the source optical emission behaviour with unprecedented detail. The analysis of the colour indices reveals that the flux variability can be interpreted in terms of two components: longer-term variations occurring on a fewday time scale appear as mildly-chromatic events, while a strong bluer-when-brighter chromatism characterizes very fast (intraday) flares. By decoupling the two components, we quantify the degree of chromatism inferring that longer-term flux changes imply moving along a ∼0.1 bluerwhen- brighter slope in the B − R versus R plane; a steeper slope of ∼0.4 would distinguish the shorter-term variations. This means that, when considering the long-term trend, the B-band flux level is related to the R-band one according to a power law of index ∼1.1. Doppler factor variations on a “convex” spectrum could be the mechanism accounting for both the long-term variations and their slight chromatism. Reig Torres, Pablo, Pablo.Reig@uv.es

Accurate astrometric and photometric calibrations of all-sky photographic surveys, such as the Palomar Quick-V survey and the UK SERC-J survey, digitised for the construction of the Hubble Space Telescope Guide Star Catalog, are of extreme astrophysical value. Their wide range of applications includes, for example, galactic structure, stellar populations, extragalactic studies, and deep sky catalogs for mission planning and telescope operations. The Guide Star Photometric Catalog (GSPC-I, Lasker et al. 1988) provides stellar calibration sequences, placed approximately in the center of each survey plate, with a limiting magnitude of V = 15 mag. The goal of our program is to extend these calibrators to V = 20 mag in the Johnson-Kron-Cousins B, V and R passbands, with an accuracy of 0.05 mag. This is accomplished by taking CCD frames centered on the faintest star of each GSPC-I sequence. Typically, both long and short exposures are acquired in each field in order to link the bright and faint ends of the sequence.

Many astrophysical issues require adequately accurate astrometry, which is broadly based on measurement of target positions on the celestial sphere. An elementary step is the evaluation of coordinates on an image, such as a CCD frame. We discuss the results achieved by a low cost experiment aimed at assessing the location accuracy of a CCD camera by evaluation of measurement repeatability throughout a set of images of a simulated stellar field. The dispersion in the image position achieved in our experiment is of the order of 1/100 of the CCD pixel size, with dominant common mode systematic effects. After removing these terms, during the data reduction phase, we obtain a final location accuracy of 1/700 of a pixel. The source of the common mode perturbations appears to be the CCD thermal control, which induces structural deformations of the set-up and induces movement of the detector.

Faint surveys of accurate colors and proper motions are fundamental for studying the physical and kinematical properties of the stellar populations in the Galaxy. A program designed to address such issues has been initiated on selected fields utilizing prototype material from the GSC-II project (see McLean et al. in this volume, p. 431). Photographic photometry V, B-V, V-Rc, is derived down to V = 18.5 with a precision of about 0.1 mag, together with absolute proper motions to σ μ ≃ 3 mas/yr.

Accuracy in the absolute position in the sky is one of the limiting factors for pulsar timing, and timing parameters have a direct impact on the understanding of the physics of Isolated Neutron Stars (INS). This is particularly true for Geminga, the only example of radio silent neutron star known so far. We have combined the Hipparcos and Tycho catalogues, ground-based astrometric data, and Hubble Space Telescope (HST) Wide Field Planetary Camera (WFPC2) images, to yield for the mv=25.5 optical counterpart of Geminga a∼40 mas (per coordinate) uncertainty. Such a positional accuracy, unprecedented for the optical position of an object this faint, is needed to combine in phase γ-ray photons collected over more than 20 years, i.e. over 2.5 billions of the star’s revolutions.

We present new X-ray data with an improved position for the supersoft X-ray source RXJ0537.6-7033, and propose a candidate for the optical identification.

We discuss CCD UBVRI and NICMOS3 JHK observations of the young open cluster Westerlund 2, with emphasis on both reduction techniques and absolute calibrations.

Accurate astrometric and photometric calibrations of all-sky photographic surveys, such as the Palomar Quick-V survey and the UK SERC-J survey, digitised for the construction of the Hubble Space Telescope Guide Star Catalog, are of extreme astrophysical value. Their wide range of applications includes, for example, galactic structure, stellar populations, extragalactic studies, and deep sky catalogs for mission planning and telescope operations. The Guide Star Photometric Catalog (GSPC-I, Lasker et al. 1988) provides stellar calibration sequences, placed approximately in the center of each survey plate, with a limiting magnitude of V = 15 mag. The goal of our program is to extend these calibrators to V = 20 mag in the Johnson-Kron-Cousins B, V and R passbands, with an accuracy of 0.05 mag. This is accomplished by taking CCD frames centered on the faintest star of each GSPC-I sequence. Typically, both long and short exposures are acquired in each field in order to link the bright and faint ends of the sequence.

Measurements of precise positions of optical counterparts of extragalactic radio-sources, with the aim to compare them with VLBI positions, is in progress at Torino Observatory. The Carlsberg Automatic Meridian Circle Catalogue (CAMC) is used for plate reductions. Presently, about 40% of the plate material required to complete the project has been taken and some significant improvements have been made both in the material and the reduction methods. Improvements are also due to the publication of a new volume of the CAMC catalogue that significantly increases the number of stars in the fields.

High precision work in photographic astrometry requires accurate monitoring of the telescope+filter+emulsion system being used.

We discuss CCD UBVRI and NICMOS3 JHK observations of the young open cluster Westerlund 2, with emphasis on both reduction techniques and absolute calibrations.

Measurements of precise positions of optical counterparts of extra-galactic radio-sources, with the aim to compare them with VLBI positions, is in progress at Torino Observatory. The Carlsberg Automatic Meridian Circle Catalogue (CAMC) is used for plate reductions. Presently, about 40% of the plate material required to complete the project has been taken and some significant improvements have been made both in the material and the reduction methods. Improvements are also due to the publication of a new volume of the CAMC catalogue that significantly increases the number of stars in the fields.

Three windows towards the Galactic bulge, located at (l, b) = (1.6,-2.8), (5.2,-3.5), and (4.2,-4.8), were identified from deep astrometric plates. Deep BVRI CCD photometry of these fields reaching V = 18.5 was obtained at the ESO Dutch telescope. The color-color and color magnitude diagrams of these fields allow us to select different bulge tracers, including blue horizontal branch stars, red clump giants, and RGB tip stars, as well as disk main-sequence stars. A first catalogue of some 2000 red clump giants was constructed, and measurement of their proper motions in under way. We are deriving absolute proper motions in the Hipparcos system using a two step procedure. First, plates from the Cordoba archive of the Astrographic Catalogue (epochs 1903-1913) are used in combination with recent plates from theESO GPO telescope to tie a set of intermediate magnitude field stars in the Hipparcos system of positions and proper motions. Second, deeper intermediate epoch (1958) and final epoch CCD images (epoch 1996.5) are used to determine the absolute proper motions of the fainter bulge stars. The average uncertainty in the absolute proper motion of a single giant, based on a preliminary sample of few tens of stars, is 0”.006 yr-1. This relatively small error, in combination with the sample size, would allow usto study the shape of the velocity ellipsoid for the different Galactic components present in the inner regions as function of Galactocentric distance, and also to measure an accurate distance to the Galactic center and the mass of the bulge. In addition, we identified about 20 faint objects which are potential members of the Sgr dwarf, based on their location in the color-magnitude diagrams, and are also measuring their proper motions.Other windows with measured proper motions are located along the Galactic minor axis, including Baade’s window at l, b = (1, −4) (Spaenhauer, A., Jones, B. F., &: Whitford, A. E., 1992, A3, 103, 297), and the Plaut field at l, b = (0, - 8 ) (Mendez, R. et al., 1997, in 4th ESO/CTIO Workshop on “The Galactic Center”, in press). Our proper motions are complementary, probing the kinematics off the Galactic minor axis, where the signature of rotation should be evident. The fields chosen for this study overlap fields that the MACHO project is following since 1993. Their variable star database would provide with excellent tracers of different populations. The 3-D motions of these different Galactic components would be measured for the first time. These include RR Lyrae tracers of the inner metal-poor halo, Miras, LPVs and delta Scuti stars tracers of the metal-rich bulge, and eclipsing binaries tracers of the Galactic disk (Minniti, D., et al., 1996, in IAP Coll. on “Variable Stars and the Astrophysical Returns of Microlensing Surveys”, ed. R. Ferlet, p. 257; Alcock, C, et al., 1997, astro-ph/9707311).

We present new X-ray data with an improved position for the supersoft X-ray source RXJ0537.6–7033, and propose a candidate for the optical identification.The source was initially designated as RXJ0537.7–7034 because there was a high uncertainty in the position, at the edge of the field of the ROSAT PSPC (Orio & Ögelman 1993). It was later observed three more times by the ROSAT PSPC at intervals of approximately 6 months, from the beginning of 1992 to the end of 1993. The change of the name is due to the new, more precise position obtained in these observations. The count rate was 0.021 ± 0.005 count s−1 in the first 1992 observation and remained at the same level in the second 1992 observation. The source was not detected in the first half of 1993, with an upper limit of 0.002 count s−1; finally in 1993 December it was detected with only 0.0035±0.0007 count s−1. It seems therefore to be very variable.

High precision work in photographic astrometry requires accurate monitoring of the telescope+filter+emulsion system being used.