Antimatter research in Space

Two of the most compelling issues facing astrophysics and cosmology today are to understand the nature of the dark matter that pervades the universe and to understand the apparent absence of cosmological antimatter. For both issues, sensitive measurements of cosmic-ray antiprotons and positrons, in a wide energy range, are crucial. Many different mechanisms can contribute to antiprotons and positrons production, ranging from conventional reactions up to exotic processes like neutralino annihilation. The open problems are so fundamental (i.e.: is the universe symmetric in matter and antimatter ?) that experiments in this field will probably be of the greatest interest in the next years. Here we will summarize the present situation, showing the different hypothesis and models and the experimental measurements needed to lead to a more established scenario.Comment: 10 pages, 7 figures, Invited talk at the 18th European Cosmic Ray Symposium, Moscow, July 2002, submitted to Journal of Physics

The primordial environment of super massive black holes: large scale galaxy overdensities around z∼6z\sim6 QSOs with LBT

We investigated the presence of galaxy overdensities around four $z\sim6$ QSOs, namely SDSS J1030+0524 (z = 6.28), SDSS J1148+5251 (z = 6.41), SDSS J1048+4637 (z = 6.20) and SDSS J1411+1217 (z = 5.95), through deep $r$-, $i$- and $z$- band imaging obtained with the wide-field ($\sim23'\times25'$) Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT). We adopted color-color selections within the $i-z$ vs $r-z$ plane to identify samples of $i$-band dropouts at the QSO redshift and measure their relative abundance and spatial distribution in the four LBC fields, each covering $\sim8\times8$ physical Mpc at $z\sim6$. The same selection criteria were then applied to $z$-band selected sources in the $\sim$1 deg$^2$ Subaru-XMM Newton Deep Survey to derive the expected number of dropouts over a blank LBC-sized field ($\sim$0.14 deg$^2$). The four observed QSO fields host a number of candidates larger than what is expected in a blank field. By defining as $i$-band dropouts objects with $z_{AB}1.4$ and undetected in the $r$-band, we found 16, 10, 9, 12 dropouts in SDSS J1030+0524, SDSS J1148+5251, SDSS J1048+4637, and SDSS J1411+1217, respectively, whereas only 4.3 such objects are expected over a 0.14 deg$^2$ blank field. This corresponds to overdensity significances of 3.3, 1.9, 1.7, 2.5$\sigma$, respectively. By considering the total number of dropouts in the four LBC fields and comparing it with what is expected in four blank fields of 0.14 deg$^2$ each, we find that high-z QSOs reside in overdense environments at the $3.7\sigma$ level. This is the first direct and unambiguous measurement of the large scale structures around $z\sim6$ QSOs. [shortened]Comment: 12 pages, 8 figures. Accepted for publication in A&

Bone mineral density in patients on home parenteral nutrition: a follow-up study.

Home artificial nutrition

Cytarabine-related lung infiltrates on high resolution computerized tomography: a possible complication with benign outcome in leukemic patients.

Potentially fatal lung toxicity occurs in 12-20% of leukemic patients treated with cytarabine especially at intermediate to high doses, usually presenting as noncardiogenic pulmonary edema (NCPE). Anecdotally the association between cytarabine and the onset of bronchiolitis obliterans organizing pneumonia (BOOP) has been reported. We describe here three cases of patients affected by acute myeloid leukemia (AML) treated with chemotherapeutic regimens including high dose cytarabine, who developed early onset of fever, mild dyspnea, moderate hypoxemia on arterial blood gas analysis and lung infiltrates documented by high-resolution computerized tomography (HRCT), with a more indolent behaviour and a benign clinical outcome, compared with similar cases previously reported in the literature. Our cases widen the spectrum of clinical features of cytarabine-related toxicity in leukemic patients

THREE-DIMENSIONAL SCAFFOLDS FOR IN VITRO CULTURE OF FELINE OOCYTES.

The cumulus-denuded oocytes (CDOs) are not commonly involved in the assisted reproductive techniques (ARTs), as the absence of their surrounding cumulus cells negatively affects their maturational and developmental competence in vitro. In some cases these gametes could represent an interesting option for widening the germinal pool of high value individuals with very precious genetic material and could be the only genetic source when the selected cumulus-oocyte complexes (COCs, grade I) are cryopreserved. Therefore, enriched culture conditions to improve the CDOs in vitro full competence should be adopted. The innovative three-dimensional (3D) scaffolds, derived from the bioengineering and nanotechnology research, ensure the optimal culture conditions to maintain the cells physiological conformation and behavior as in the in vivo environment. In this thesis, the association of 3D barium alginate microcapsules with competent COCs was used to improve the in vitro performances of domestic cat CDOs. The results showed that the 3D BA microcapsules are suitable systems for the in vitro culture of feline oocytes, as their viability and in vitro maturation rates and embryonic development were similar to those obtain in the traditional 2D system. The enriched co-culture condition did not improve the in vitro competence of CDOs, as their full maturational (TI-MII) rates and late embryo stages (morulae and blastocysts) were similar to those of the CDOs cultured separately or to those of the COCs control. However, the presence of CDOs in the co-culture with COCs improved significantly the in vitro developmental rates of the high competence oocytes, presumably for the paracrine action of some specific oocyte-secreted factors (OSFs). A better knowledge of the expression profiles of potential oocyte quality markers, as the OSFs, and how they could differ from COCs and CDOs in the 3D and 2D systems could help the design of the optimal enriched culture conditions for the domestic cat low competence oocytes

Astrophysical Implications of a Visible Dark Matter Sector from a Custodially Warped-GUT

We explore, within the warped extra dimensional framework, the possibility of finding anti-matter signals in cosmic rays (CRs) from dark matter (DM) annihilation. Exchange of order 100 GeV radion, an integral part of our setup, generically results in Sommerfeld enhancement of the annihilation rate for TeV DM mass. No dark sector is required to obtain boosted annihilation cross sections. A mild hierarchy between the radion and DM masses can be natural due to the pseudo-Goldstone boson nature of the radion. Implications of Sommerfeld enhancement in warped grand unified theory (GUT) models, where proton stability implies a DM candidate, are studied. We show, via partially unified Pati-Salam group, how to incorporate a custodial symmetry for Z->b\bar b into the GUT framework such that a few TeV Kaluza-Klein (KK) mass scale is allowed by precision tests. The model with smallest fully unified SO(10) representation allows us to decouple the DM from the electroweak sector. Thus, a correct DM relic density is obtained and direct detection bounds are satisfied. Looking at robust CR observables, a possible future signal in the \bar p / p flux ratio is found. We show how to embed a similar custodial symmetry for the right handed tau, allowing it to be strongly coupled to KK particles. Such a scenario might lead to observed signal in CR positrons; however, the DM candidate in this case can not constitute all of the DM in the universe. Independently of the above, the strong coupling between KK particles and tau's can lead to striking LHC signals.Comment: 53 pages, 9 figure