Rendering Pacioli's rhombicuboctahedron

We analyze the glass rhombicuboctahedron (RCO) appearing in a famous painting of Pacioli (1495), considering the extent to which it might agree with a physically correct rendering of a corresponding glass container half-filled with water. This investigation shows that it is unlikely that the painter of the RCO was looking at such a physical object. We then ask what a proper rendering of such an object might look like. Our computer renderings, which take into account multiple internal and external reflections and refractions, yield visual effects that differ strongly from their depictions in the painting. Nevertheless, the painter of the RCO has clearly succeeded in providing a rendering that appears plausible and awe-inspiring to almost all observers

Clinical and Biological Features, Treatment and Long-Term Outcome of 65 Children with Ph- Myeloprolipherative Disorders (MPD).

Introduction: MPD rarely occur in children and published data of pediatric patients (pts) are limited. In adults, current diagnostic criteria are those of the WHO2008 and the therapeutic options are supported by controlled studies. From our experience, we suggested that the biological markers show a clinical relevance in Ph- MPD children and may influence their management. Patients and methods: We retrospectively analyzed 65 pts aged 20 years (yrs) at diagnosis (dx) with Ph-negative MPD, observed between December 1981 and March 2009. Dx was performed according to the PVSG or WHO criteria. Since 2002, 52/65 pts were studied for JAK2 mutations, polycytemia rubra vera-1 (PRV-1) RNA expression, thrombopoietin (TPO) and its receptor (c-MPL) mutations, erythropoietin receptor (EPO-r) gene mutations, spontaneous endogenous erythroid colony (EECs) growth, clonality on female pts. Results: Thirty-nine females and 26 males with a median age at dx of 14 yrs were classified as follow: 34 (52%) essential thrombocythemia (ET), 16 (24.5%) familial thrombocythemia (FT), 11 (17%) polycythemia vera (PV), 3 (4.5%) familial polycythemia (FP) and 1 idiopathic myelofibrosis (IM). Clinical and biological data, treatment and outcome are reported. Pts with familial disease were younger than those with the sporadic form (p<.05). Hematocrit (Hct) values were higher in ET than in FT pts (p .0047). Fifty pts underwent a bone marrow aspirate and biopsy (15 FT and FP children were excluded). No chromosome abnormalities were found. Overt fibrosis was present in 1 pt. Symptoms at dx were recorded in 21/64 pts (33%) and splenomegaly was present in 13/64 (20%), more frequently in sporadic disease pts. The JAK2V617F mutation was found in 47.5% of ET and 27% of PV. Clonal myelopoiesis was present in 7/11 (63.5%) ET and 2/3 PV females. None of the FT and FP pts showed JAK2V617F mutations or clonality. EECs grew in 58% of ET, in 42% of FT and in 40% of PV. PRV-1 RNA overexpression was found in 29/44 pts (66%). No EECs growth or EPO-r gene mutation was found in FP pts. The median EPO level was 5 mU/ml (1.1–16.4) in polycythemic pts. MPLS505A mutations were detected in15/16 FT pts and a novel HIF2A mutation in 1 FP pt. Treatment was modified during follow-up (f-up): 15 children did not undergo any treatment and 16 pts received more than one cytoreductive drugs. Phlebothomies were carried out in 9 polycythemic pts. Overall, 26 pts were treated with different cytoreductive drugs (hydroxyurea, interferone-alpha, anagrelide and pipobroman). Because of the persistently higher platelet (PLT) count, ET children needed more cytoreductive drugs than FT pts (p .0006). Anti-platelet agents were used in 40 pts and stopped in 30. No hemorrhagic events were recorded; 3 pts (5%) developed thromboses. Eight pts had 11 pregnancies (4 abortions: 2 spontaneous). Five pts showed progressive splenomegaly, 2 (1 PV and 1 ET, untreated) of them developed IM. Two pts developed a cancer. All pts are alive after a median f-up of 10 yrs. Conclusions: This represents the largest reported series of pediatric MPD. A broad familial work-up combined to molecular analyses allowed us to characterize the MPD disorders in our pediatric population, to plan suitable treatments and to better manage their disease. ET (34 pts) FT (16 pts) PV (11 pts) FP (3 pts) IM (1 pt) -------------------------------------------------------------------------------- M/F 10/24 7/9 8/3 1/2 F Age at Dx (yrs) 15.53 (5.24–19.75) 11.91 (0.22–17.45) 16.47 (3.68–18.8) 11.18 (11.18–14.16) 19 WBC x 109/L 9,88 (5,62–22,22) 8,43 (5,17–16,06) 6,73 (4,86–28,67) 6,76 (5,4–6,77) 13,35 Hct % 41.65 (29–53) 36.15 (32.3–42) 53.9 (50–72.5) 53.20 (42.4–54.5) 31 PLT x 109/L 1109 (633–2800) 990,5 (611–2950) 217 (166–945) 207 (202–271) 995 Symptoms 12/33 (36%) 4/16 (25%) 5/11 (45%) 0/3 no Splenomegaly 8/34 (23.5%) 2/15 (13%) 3/11 (27%) 0/3 no Anti-platelet agents 27/34 (79.4%) 9/16 (56%) 4/11 (36%) 0/3 no Cytoreductive drugs 23/34 (68%) 2/16 (12.5%) 1/11 (9%) 0/3 no EECs pos 11/19 (58%) 5/12 (42%) 4/10 (40%) 0/3 no PRV-1 RNA overexpr 14/19 (74%) 6/12 (50%) 6/10 (60%) 3/3 (100%) yes JAK2 V617F mut 10/21 (47.5%) 0/13 3/11 (27%) 0/3 no Monoclonality 7/11 (63.5%) 0/7 2/3 (66%) 0/2 yes MPLS505A mut 0/15 15/16 (94%) – – – Thromboses 1/34 (3%) 2/16 (12.5%) 0/11 0/3 no Pregnancies 9 2 – – – F-up (yrs) 10.02 (0.37–27.28) 11.02 (0.86–26.96) 9 (0.25–17.14) 2 (2–9) 1

A multisite photometric campaign on the pre-main-sequence d Scuti pulsator IP Persei

We present the results of a photometric multisite campaign on the d Scuti Pre-Main-Sequence star IP Per. Nine telescopes have been involved in the observations, with a total of about 190 h of observations over 38 nights. Present data confirms the multiperiodic nature of this star and leads to the identification of at least nine pulsational frequencies. Comparison with the predictions of linear non-adiabatic radial pulsation models allowed us to identify only five of the nine observed frequencies, and to constrain the position of IP Per in the HR diagram. The latter is in good agreement with the empirical determination of the stellar parameters obtained by Miroshnichenko et al. (2001, A&A, 377, 854). An initial interpretation of the observed frequencies using the Aarhus non-radial pulsation code suggests that three frequencies could be associated with non-radial (l = 2) modes. Finally, we present new evolutionary and pulsation models at lower metallicity (Z = 0.008) to take into account the possibility that IP Per is metal deficient, as indicated by Miroshnichenko et al. (2001, A&A, 377, 854). ESO 2006

Galactic globular cluster stars: From theory to observation

Available from: http://www.mpa-garching.mpg.de / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Optical and x-ray monitoring, doppler imaging, and space motion of the young star par 1724 in Orion

Available from TIB Hannover: RN 9303(436) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman