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We present a project that aims to provide a complete theoretical and observational framework for an as yet unexplored class of variable stars, the ultralong-period Cepheids (P longer than 80–100 days). Given their very high luminosities (MV up to −7 mag), with the Hubble Space Telescope we will be able to observe them easily in stellar systems located at large distances (~ 100 Mpc). This limit will be further increased, out to the Hubble flow (~ 350 Mpc), using future ground-based facilities such as the European Extremely Large Telescope. The nature of their pulsation is as yet unclear, as is their evolutionary status, which seems different from the central helium-burning phase generally associated with classical Cepheids. These objects have been found to cover a very large metallicity range, from [Fe/H] ~ −2 dex to solar values, and they are located in heterogeneous stellar systems, from dwarf to spiral galaxies. Once completely characterized, they could provide a crucial test, since they have been found in all Type Ia supernova host spiral galaxies that have been monitored for variability over long periods and that currently offer sound constraints on the estimated value of the Hubble constant.
There is much evidence to indicate the ability of Indinavir (IND) to reduce Cryptosporidium parvum infection in both in vitro and in vivo models. However, there are limitations to the administration of IND as such, due to its renal toxicity and the high rate of metabolism and degradation. We aimed to encapsulate IND in biodegradable poly (D,L-lactide-co-glycolide) nanoparticles (Np) and to engineer their surface by conjugation with an anti-Cryptosporidium IgG polyclonal antibody (Ab). Tetramethylrhodamine-labelled Np were loaded with IND and modified by conjugation with an Ab. The IND-loaded modified Np (Ab-TMR-IND-Np) did not show any change, as demonstrated by chemical analysis studies. Simultaneous addition of 50μM Ab-TMR-IND-Np and excysted oocysts to the cell culture resulted in complete inhibition of the infection. In C. parvum-infected cells, the extent to which the infection decreased depended on the duration of treatment with the Ab-TMR-IND-Np. The antibody-engineered Np loaded with IND were able to target C. parvum in infected cells and therefore might represent a novel therapeutic strategy against Cryptosporidium sp. infection. Moreover, the use of Np as an IND delivery device, allows the development of a more appropriate dose formulation thereby reducing the IND side effects.
The Fraser's dolphin (Lagenodelphis hosei) is distributed in tropical and subtropical pelagic waters worldwide between 30°N and 30°S. The first report of this species in Brazilian waters occurred only in 1997. The northernmost report, up to now, occurred in Ceará State in 2001. The purpose of this work is to report a live stranding of Lagenodelphis hosei in Caburé city situated in Maranhão State (01°31′S 45°07′W), northern Brazilian coast. This stranding was reported through four photographs donated by a fisherman in August 2006. The specimen had an estimated length of 250 cm and was apparently emaciated, indicating that the dolphin could have presented some pathology. Despite the conservation activities, the meat of the stranded specimen was used as a food source by local fishermen and the carcass was left in the sea before the arrival of the researchers. This is the first confirmed report of a specimen of L. hosei for the northern Brazilian coast.
We introduce the SMC in space and time, a large coordinated space and ground-based program to study star formation processes and history, as well as variable stars, structure, kinematics and chemical evolution of the whole SMC. Here, we present the Colour-Magnitude Diagrams (CMDs) resulting from HST/ACS photometry, aimed at deriving the star formation history (SFH) in six fields of the SMC. The fields are located in the central regions, in the stellar halo, and in the wing toward the LMC. The CMDs are very deep, well beyond the oldest Main Sequence Turn-Off, and will allow us to derive the SFH over the entire Hubble time.
The blue compact dwarf galaxy I Zw 18 holds the record of the lowest metallicity ever observed in the local universe. As such, it represents the closest analog to primordial galaxies in the early universe. More interestingly, it has recurrently been regarded as a genuinely young galaxy caught in the process of forming in the nearby universe. However, stars of increasingly older ages are found within I Zw 18 every time deeper high-resolution photometric observations are performed with the Hubble Space Telescope (HST): from the original few tens of Myrs to, possibly, several Gyrs. Here we summarize the history of I Zw 18 age and present an ongoing HST/ACS project which allowed us to precisely derive the galaxy distance by studying its Cepheid variables, and to firmly establish the age of its faintest resolved populations.
We present results from new deep HST/ACS photometry of I Zw 18, the most metal-poor blue compact dwarf galaxy in the nearby universe. It has been previously argued that this is a very young system that started forming stars only ≲500 Gyr ago, but other work has hinted that older (≳1 Gyr) red giant branch (RGB) stars may exist in this galaxy. Our deeper data indeed reveal evidence for an RGB. Underlying old (≳1 Gyr) populations are therefore present in even the most metal-poor systems, implying that star formation started at z ≳ 0.1. The RGB tip (TRGB) magnitude and the properties of Cepheid variables identified from our program indicate that I Zw 18 is farther away (D = 19.0 ± 1.8 Mpc) than previously believed.
In the framework of an ongoing ACS@HST project (HST program #10586, PI: Aloisi) we have obtained deep multi-color imaging of the very metal-poor Blue Compact Dwarf galaxy IZw18. The data were acquired in time-series fashion to allow the identification of Classical Cepheids (CCs). The main aim of this project is to constrain both the distance and the Star Formation History of the galaxy. However, as a byproduct these data also provide new insights into the properties of CCs at very low metallicities. We have identified 24 candidate CCs in IZw18. New theoretical pulsation models of CCs specifically for the low metallicity of this primordial galaxy (Z=0.0004, Y=0.24) have been computed to interpret our results.
Background: The aim of this prospective, randomized, blinded study was to compare analgesic efficacy of continuous paravertebral and epidural analgesia for post-thoracotomy pain. Methods: Forty-two ASA physical status II–III patients undergoing lung resection surgery were randomly allocated to receive post-thoracotomy analgesia with either a thoracic epidural (group EPI, n = 21) or paravertebral (group PVB, n = 21) infusion of 0.2% ropivacaine (infusion rate: 5–10 mL h−1). The degree of pain at rest and during coughing, haemodynamic variables and blood gas analysis were recorded every 12 h for the first 48 h. Results: The area under the curve of the visual analogue pain score during coughing over time was 192 (60–444) cm h−1 in group EPI and 228 (72–456) cm h−1 in group PVB (P = 0.29). Rescue morphine analgesia was required in four patients of group EPI (19%) and five patients of group PVB (23%) (P = 0.99). The PaO2/FiO2 ratio reduced significantly from baseline values in both groups without between-group differences. The median (range) percentage reduction of systolic arterial pressure from baseline was −9 (0 to −9)% in group PVB and −17 (0 to −38)% in group EPI (P = 0.02); while clinically relevant hypotension (systolic arterial pressure decrease >30% of baseline) was observed in four patients of group EPI only (19%) (P = 0.04). Patient satisfaction with the analgesia technique was 8.5 (8–9.8) cm in group EPI and 9 (7.5–10) cm in group PVB (P = 0.65). Conclusions: Continuous thoracic paravertebral analgesia is as effective as epidural blockade in controlling post-thoracotomy pain, but is associated with less haemodynamic effects.
The prismatic variety of fluoro-edenite, a new amphibole found in lavas from Mt Etna in Biancavilla (Catania Province, Sicily, Italy), has been characterized by μ-Raman and μ-FTIR spectroscopy. The wavenumbers at which the bands are detected in the μ-Raman and μ-FTIR spectra are compared with tremolite, asbestos the chemical and crystallographic characteristics of which are very similar to those of fluoro-edenite.
Coeliac disease (CD) is a malabsorptive disorder of the small intestine resulting from ingestion of
gluten. The HLA risk factors involved in CD are well known but do not explain the whole genetic
susceptibility. Several regions of potential linkage on chromosomes 3q, 5q, 10q, 11q, 15q and 19q
have already been reported in the literature. These six regions were analyzed with the Maximum Lod
Score method on a dense set of markers. A new sample of 89 Italian sibpairs was available for study.
There was no evidence for linkage for any of the regions tested, except for chromosome 5q. For this
region, our data, as well as a sample of 93 sibpairs from our first genome screen (Greco et al. 1998),
are compatible with the presence of a risk factor for CD with a moderate effect.
This paper reports the capture of seven adult Pipistrellus nathusii including a lactating female mist-netted in July 1997 in Varese province (northern Italy). This record represents the first identification of a breeding female Nathusius' pipistrelle in the south part of the Alps. Other data on the reproduction of this species in Europe are discussed in order to reconsider its distribution and breeding sites.
Coeliac disease (CD) is a multigenic and multifactorial enteropathy triggered by gluten-composing
proteins. A possible involvement of the intestinal Aminopeptidase N (APN) was investigated by an
association analysis. SSCP analysis detected four variants at position 281, 378, 956 and 2957
(referred to no. g178535, GenBank) that were studied in 193 Italian CD families. The haplotypic
combinations were determined from family segregation and pairwise linkage disequilibria
(D′ = D/Dmax) between the polymorphic sites were calculated. Significant D′ values ranged between 0.78
and 0.31. Association with CD was tested by TDT (Transmission Disequilibrium Test) utilizing as
markers the nucleotide substitutions and their haplotypic combinations. No statistically significant
transmission distortion to the probands or to their clinically silent sibs was observed. Our data
exclude an involvement in CD of the tested markers and of further undetected variation in strong
linkage disequilibrium (D′ ≅ 1) with them. The power of the test was not adequate to detect an
association with an unknown polymorphism which is not in complete linkage disequilibrium with
RR Lyrae stars both in the field and in clusters can be used to derive the metal abundance of the regions and systems where they are found.
(1) New data have been collected on a sample of field ab-type RR Lyraes with the aim of studying the composition of the halo and the disk of the galaxy, (Clementini et al. 1992a, in preparation), using the relation found by Clementini et al. (1991), (hereafter CTM91), between [Fe/H] and the equivalent width of the Ca II K-line W‘(K). (2) A quantitative chemical abundance analysis of the ab type RR Lyrae (V29) in the globular cluster M4 has been performed using high resolution, high S/N spectroscopy. We obtain [Fe/H]=–1.3 ± 0.2 and the α– elements (Mg and Ti) are overabundant by 0.6 dex. These results are in good agreement with determinations from high resolution spectra of giants and blue horizontal branch stars (Clementini et al. 1992b, in preparation).
Given the uncertainties in the derivation of the current and past SFR in galaxies of any kind, the SF regime in irregulars is subject of wide debate. Since the most direct information on the stellar populations and relative histories in any system can be derived from their CMD, we have undertaken a project for accurately studying the CMDs and luminosity functions (LF) of nearby, well resolved, irregulars. The method proceeds on two tracks: a) we have developed a numerical code for Montecarlo simulations of CMDs and b) we have taken deep and accurate CCD photometry of several galaxies and derived the corresponding CMDs and LFs. The comparison of the observational data with the corresponding theoretical expectations provides several constraints on the SF history and on the IMF of the analysed objects. We do not pretend to reach unique conclusions on the evolution of irregular galaxies, but we can sensibly reduce the range of possible interpretations.
All the irregulars in our sample were selected from the DDO Catalogue and were supposed to belong to the Local Group. Detailed descriptions of the data acquisition and reduction and of the simulation code can be found in Tosi et al. (1991). In the following we briefly summarize the results relative to Sextans B, NGC 3109 and DDO 210.
The process of star formation (SF) and the modalities with which it occurs in galaxies of different sizes are still poorly understood. On the other hand, interpretation of the chemical and photometric properties of galaxies requires the adoption of adequate laws for the SF rate and Initial Mass Function (IMF) in model computations. Dwarf irregular galaxies in the Local Group offer the chance to study their SF history through analysis of their HR diagrams, which can be derived down to V 25, corresponding to MV0, i.e. to main sequence stars of 2 M⊙. Therefore, for these galaxies, we can derive information on the star formation activity which has occurred over the last 1 Gyr approximately. In this framework, we have undertaken CCD observations of Dwarf irregular galaxies in the Local Group with ESO telescopes and briefly present here the results obtained for DDO 210, Sextans B and NGC 3109.
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