Two New Candidate Planets in Eccentric Orbits

Doppler measurements of two G-type main-sequence stars, HD210277 and HD168443, reveal Keplerian variations that imply the presence of companions with masses (M sin i) of 1.28 and 5.04 M_Jup and orbital periods of 437 d and 58 d, respectively. The orbits have large eccentricities of e=0.45 and e=0.54, respectively. All 9 known extrasolar planet candidates with a=0.2-2.5 AU have orbital eccentricities greater than 0.1, higher than that of Jupiter (e=0.05). Eccentric orbits may result from gravitational perturbations imposed by other orbiting planets or stars, by passing stars in the dense star-forming cluster, or by the protoplanetary disk. Based on published studies and our near-IR adaptive optics images, HD210277 appears to be a single star. However, HD168443 exhibits a long-term velocity trend consistent with a close stellar companion, as yet undetected directly.Comment: AASTeX, 31 pages including 10 Postscript figures, to appear in the Astrophysical Journal (July 1999

Amplicon rearrangements during the extrachromosomal and intrachromosomal amplification process in a glioma

International audienceThe mechanisms of gene amplification in tumour cells are poorly understood and the relationship between extrachromosomal DNA molecules, named double minutes (dmins), and intrachromosomal homogeneously staining regions (hsr) is not documented at nucleotide resolution. Using fluorescent in situ hybridization and whole genome sequencing, we studied a xenografted human oligodendroglioma where the co-amplification of the EGFR and MYC loci was present in the form of dmins at early passages and of an hsr at later passages. The amplified regions underwent multiple rearrangements and deletions during the formation of the dmins and their transformation into hsr. In both forms of amplification, non-homologous end-joining and microhomology-mediated end-joining rather than replication repair mechanisms prevailed in fusions. Small fragments, some of a few tens of base pairs, were associated in contigs. They came from clusters of breakpoints localized hundreds of kilobases apart in the amplified regions. The characteristics of some pairs of junctions suggest that at least some fragments were not fused randomly but could result from the concomi-tant repair of neighbouring breakpoints during the interaction of remote DNA sequences. This characterization at nucleotide resolution of the transition between extra-and intrachromosome amplifications highlights a hitherto uncharacterized organization of the amplified regions suggesting the involvement of new mechanisms in their formation

Starspots on the fastest rotators in the Beta Pic moving group

Aims: We carried out high-resolution spectroscopy and BV(I)_C photometric monitoring of the two fastest late-type rotators in the nearby Beta Pictoris moving group, HD199143 (F7V) and CD-641208 (K7V). The motivation for this work is to investigate the rotation periods and photospheric spot patterns of these very young stars, with a longer term view to probing the evolution of rotation and magnetic activity during the early phases of main-sequence evolution. We also aim to derive information on key physical parameters, such as rotational velocity and rotation period. Methods: We applied maximum entropy (ME) and Tikhonov regularizing (TR) criteria to derive the surface spot map distributions of the optical modulation observed in HD199143 (F7 V) and CD-641208 (K7V). We also used cross-correlation techniques to determine stellar parameters such as radial velocities and rotational velocities. Lomb-Scargle periodograms were used to obtain the rotational periods from differential magnitude time series. Results: We find periods and inclinations of 0.356 days and 21.5deg for HD199143, and 0.355 days and 50.1deg for CD-641208. The spot maps of HD199143 obtained from the ME and TR methods are very similar, although the latter gives a smoother distribution of the filling factor. Maps obtained at two different epochs three weeks apart show a remarkable increase in spot coverage amounting to ~7% of the surface of the photosphere over a time period of only ~20 days. The spot maps of CD-641208 from the two methods show good longitudinal agreement, whereas the latitude range of the spots is extended to cover the whole visible hemisphere in the TR map. The distributions obtained from the first light curve of HD199143 show the presence of an extended and asymmetric active longitude with the maximum filling factor at longitude ~325degree.Comment: Accepted by A&A. 13 pages, 13 figures (4 online included), 5 Table

Results of surgery for irreversible moderate to severe mitral valve regurgitation secondary to myocardial infarction

Objective: Moderate to severe irreversible mitral regurgitation secondary to myocardial infarction is an independent risk factor for reduced long-term survival. Late effects of correction of mitral incompetence concomitant with coronary artery bypass grafting (CABG) are less well known and the choice of mitral valve procedure is still debated. Methods: From 1988 to 1998, 93 consecutive patients (mean age 63±9 years) were treated for moderate to severe irreversible mitral regurgitation secondary to myocardial infarction; 84 were in NYHA functional class III-IV and 19 were in cardiogenic shock. Thirty-seven patients underwent emergency surgery. Perioperative intraaortic balloon pump (IABP) was necessary in 33 patients. Follow-up ranged from 6 months to 12 years (mean 51 months±41). Results: Mitral valve was repaired in 30 patients and replaced in 63. Replacement was preferably performed in patients with major displacement of papillary muscle and in patients with acute papillary muscle rupture. CABG (3.4 distal anastomoses) was performed in all patients and was complete in 92%. Early mortality was 15% (14/93). Multivariable analysis identified need for IABP (P=0.005) and COPD (P=0.02) as risk factors for early death. Emergency surgery had only a trend (P=0.15) for increased mortality; age, low ejection fraction, repair vs. replacement had no influence. Actuarial survival rates at 1, 5 and 10 years were 81, 65 and 56%, respectively. Late survival was similar in patients with replacement or repair (P=0.46). At last follow-up, all but one patient were in NYHA functional class I or II. Conclusions: Combined mitral valve procedure and myocardial revascularization, as complete as possible, for moderate to severe mitral regurgitation secondary to myocardial infarction achieve satisfactory early and late outcome despite the increased operative mortality. Acute papillary muscle rupture, severe restriction of the mitral valve by major displacement of the papillary muscle are better managed by valve replacemen

The ``Outside-In'' Outburst of HT Cassiopeiae

We present results from photometric observations of the dwarf nova system HT Cas during the eruption of November 1995. The data include the first two--colour observations of an eclipse on the rise to outburst. They show that during the rise to outburst the disc deviates significantly from steady state models, but the inclusion of an inner-disc truncation radius of about 4 $R_{wd}$ and a ``flared'' disc of semi-opening angle of $10^{\circ}$ produces acceptable fits. The disc is found to have expanded at the start of the outburst to about $0.41R_{L1}$, as compared to quiescent measurements. The accretion disc then gradually decreases in radius reaching $<0.32R_{L1}$ during the last stages of the eruption. Quiescent eclipses were also observed prior to and after the eruption and a revised ephemeris is calculated.Comment: 9 pages, 11 figures, to appear in MNRA

Influencia de la temperatura en el comportamiento alimentario de peltocephalus dumerilianus (testudines podocnemidae)

Objetivo. Analizar los comportamientos de alimentación bajo diferentes condiciones de temperatura en un grupo de neonatos de Peltocephalus dumerilianus (Testudines Podocnemididae). Materiales y Métodos. Los individuos experimentales fueron obtenidos mediante incubación en el laboratorio, se dividieron en 5 grupos al azar. Durante 2 meses con tres repeticiones a la semana se hicieron pruebas de temperatura utilizando dentro de las bandejas calentadores eléctricos, con registro continuo de temperatura mediante termómetro digital - 10 a + 60ºC (± 0.1ºC), procurando mantener un ritmo constante de incremento equivalente a 0,25ºC cada 10 minutos, hasta llegar a la temperatura seleccionada, que fue mantenida por 60 minutos en cada ensayo. Las temperaturas seleccionadas para cada ensayo, fueron: 26ºC, 30ºC, 34ºC, 38ºC y ambiente que fue de 26,8ºC en promedio. Fueron evaluados los siguientes parámetros: duración en minutos de la ingesta, tiempo de inicio de comportamientos agonísticos, presencia de dos tipos de despliegues característicos: morder y disputa por alimento. Resultados. En general todos los parámetros fueron significativos, a mayor temperatura el tiempo de ingestión fue mayor, a menor temperatura el volumen de consumo fue menor, a menor temperatura el inicio de los despliegues agonísticos fue mayor y se mantuvo una relación inversamente proporcional. Conclusiones. Los resultados mostraron que existe relación directamente proporcional entre la temperatura ambiental y los procesos de alimentación, además que se relacionaron con aspectos básicos del comportamiento lo cual se manifestó en los despliegues agonísticos observados

Influencia de la temperatura en el comportamiento alimentario de peltocephalus dumerilianus (testudines podocnemidae)

Objetivo. Analizar los comportamientos de alimentación bajo diferentes condiciones de temperatura en un grupo de neonatos de Peltocephalus dumerilianus (Testudines Podocnemididae). Materiales y Métodos. Los individuos experimentales fueron obtenidos mediante incubación en el laboratorio, se dividieron en 5 grupos al azar. Durante 2 meses con tres repeticiones a la semana se hicieron pruebas de temperatura utilizando dentro de las bandejas calentadores eléctricos, con registro continuo de temperatura mediante termómetro digital - 10 a + 60ºC (± 0.1ºC), procurando mantener un ritmo constante de incremento equivalente a 0,25ºC cada 10 minutos, hasta llegar a la temperatura seleccionada, que fue mantenida por 60 minutos en cada ensayo. Las temperaturas seleccionadas para cada ensayo, fueron: 26ºC, 30ºC, 34ºC, 38ºC y ambiente que fue de 26,8ºC en promedio. Fueron evaluados los siguientes parámetros: duración en minutos de la ingesta, tiempo de inicio de comportamientos agonísticos, presencia de dos tipos de despliegues característicos: morder y disputa por alimento. Resultados. En general todos los parámetros fueron significativos, a mayor temperatura el tiempo de ingestión fue mayor, a menor temperatura el volumen de consumo fue menor, a menor temperatura el inicio de los despliegues agonísticos fue mayor y se mantuvo una relación inversamente proporcional. Conclusiones. Los resultados mostraron que existe relación directamente proporcional entre la temperatura ambiental y los procesos de alimentación, además que se relacionaron con aspectos básicos del comportamiento lo cual se manifestó en los despliegues agonísticos observados

ECOLOGÍA POBLACIONAL DE Peltocephalus dumerilianus (TESTUDINES, PODOCNEMIDIDAE) EN DOS TRIBUTARIOS DEL RÍO NEGRO, AMAZONAS, BRASIL

In the present work about Peltocephalus dumerilianus ("big-head" Amazon turtle), an aquatic chelonian inhabiting the Am-azon basin, the sex composition was analyzed by the capture-recapture method in two tributaries of the Rio Negro, and mor-phometric parameters were compared individually and by sex. By means of a mathematical model the populational abundance was calculated. Also, through telemetry, the occupied home range was calculated according to sex, and differences among populations were established

Ovarian cycle and follicular hierarchy of Peltocephalus dumerilianus (Testudines: Podocnemididae)

Forty pairs of ovaries of mature female Peltocephalus dumerilianus (Schweigger 1812) were analyzed, to establish the morphologic monthly changes that take place during one year; we examined macroscopically the oviducts and the ovaries of specimens that the riverside inhabitants of the municipality of Barcelos, Amazons, Brazil, used for their consumption. We measured the diameter and recorded the number of enlarged ovarian follicles and corpora lutea. The results show the gradual enlargement of follicles in agreement with the reproductive period, observing that during the last third of the process; just before oviposition they become more evident. The positive relationship between the size of the female and the ovarian mass, is statistically significant (F (10.29)=3.655, p < 0.05). Follicullar sizes suggest that this species nests only once a year.Se analizaron cuarenta pares de ovarios de hembras adultas de Peltocephalus dumerilianus (Schweigger 1812), para establecer los cambios morfológicos mensuales producidos durante un año. Se llevaron a cabo exámenes macroscópicos de los oviductos y de los ovarios de especímenes que los habitantes ribereños del municipio de Barcelos, Amazonas, Brasil, utilizaron para su consumo, usando metodológicamente la medida del diámetro y conteo de los folículos ováricos y de los cuerpos lúteos. Los resultados muestran la presencia gradual de folículos acorde con la época reproductiva, resaltando que durante el último tercio del proceso, justo antes de la postura se hacen más evidentes; se analiza la relación existente entre el tamaño de la hembra y la masa ovárica, la cual es estadísticamente significativa (F (10,29)=3,655, p < 0,05). Se hace evidente la existencia de una jerarquía ovario folicular que demuestra que para esta especie solo es posible fisiológicamente una postura por año