Eccentricity Evolution of Extrasolar Multiple Planetary Systems due to the Depletion of Nascent Protostellar Disks

Most extrasolar planets are observed to have eccentricities much larger than those in the solar system. Some of these planets have sibling planets, with comparable masses, orbiting around the same host stars. In these multiple planetary systems, eccentricity is modulated by the planets' mutual secular interaction as a consequence of angular momentum exchange between them. For mature planets, the eigenfrequencies of this modulation are determined by their mass and semi-major axis ratios. But, prior to the disk depletion, self gravity of the planets' nascent disks dominates the precession eigenfrequencies. We examine here the initial evolution of young planets' eccentricity due to the apsidal libration or circulation induced by both the secular interaction between them and the self gravity of their nascent disks. We show that as the latter effect declines adiabatically with disk depletion, the modulation amplitude of the planets' relative phase of periapse is approximately invariant despite the time-asymmetrical exchange of angular momentum between planets. However, as the young planets' orbits pass through a state of secular resonance, their mean eccentricities undergo systematic quantitative changes. For applications, we analyze the eccentricity evolution of planets around Upsilon Andromedae and HD168443 during the epoch of protostellar disk depletion. We find that the disk depletion can change the planets' eccentricity ratio. However, the relatively large amplitude of the planets' eccentricity cannot be excited if all the planets had small initial eccentricities.Comment: 50 pages including 11 figures, submitted to Ap

Three Dimensional Intracellular Structure of the Cochlea Using the A-O-D-O Method

We have observed the three-dimensional intracellular structure of the organ of Corti and the spiral ganglion of the chinchilla using the aldehyde osmium-DMSO-osmium (A-O-D-O) method, and compared our findings with previous studies in the guinea pig. In cells of the spiral ganglion and the organ of Corti, microtubules and other cytoplasmic filaments were digested by OsO4 during processing to provide a clear view of membranous structures such as mitochondria, endoplasmic reticulum and Golgi apparatus. The appropriate digestion time with 0.1% OsO4 solution was found to be 60-80 hrs for the organ of Corti and 70-90 hrs for the spiral ganglion. The A-O-D-O method has been especially useful to show the organization of the endoplasmic reticulum of the outer hair cells. We have made a further characterization of the apical cistern, a reticular network which appears to link the basal body of the (vestigial) kinocilium to both Hensen\u27s body and the subsurface cisternae

Correlation of Cochlear Pathology with Auditory Brainstem and Cortical Responses in Cats with High Frequency Hearing Loss

Newborn kittens were treated with the aminoglycoside amikacin to produce a bilateral high frequency cochlear hearing loss. The degree and stability of hearing loss were confirmed by recording auditory brainstem evoked potentials (ABR audiograms). After maturation, cochleotopic frequency representation within primary auditory cortex (Al) was mapped using standard microelectrode recording techniques. The cochlear sensory epithelium was assessed with SEM and the pattern of damage compared with the ABR audiograms and cortical frequency maps. Amikacin treatment resulted in various patterns of haircell damage towards the base of the cochlea. A relatively abrupt transition between damaged and undamaged haircell regions resulted in an ABR audiogram with normal threshold to low frequencies and a high frequency elevation with a steep cut-off slope. In the cortical map, low frequency representation was normal, but anterior areas contained only neurons tuned to a common frequency which corresponded to the frequency-place position of the boundary of the haircell lesion and to the cut-off frequency of the audiogram. A large transitional zone of the cochlear lesion correlated with a gradual cut-off slope to the audiogram and again a remapping of the anterior and normally high frequency area to a common lower frequency. Haircell loss or damage (i.e. disarray of stereocilia) in lower frequency regions of the cochlea correlated with a significant reorganization of the lower frequency bands in the cortical map. We conclude from this study that the pattern of cochleotopic organization of the cortex is dependent on the pattern of activity in the ascending sensory pathway during early stages of development

On the stochastic mechanics of the free relativistic particle

Given a positive energy solution of the Klein-Gordon equation, the motion of the free, spinless, relativistic particle is described in a fixed Lorentz frame by a Markov diffusion process with non-constant diffusion coefficient. Proper time is an increasing stochastic process and we derive a probabilistic generalization of the equation $(d\tau)^2=-\frac{1}{c^2}dX_{\nu}dX_{\nu}$. A random time-change transformation provides the bridge between the $t$ and the $\tau$ domain. In the $\tau$ domain, we obtain an \M^4-valued Markov process with singular and constant diffusion coefficient. The square modulus of the Klein-Gordon solution is an invariant, non integrable density for this Markov process. It satisfies a relativistically covariant continuity equation

Analiza oborine (1923-2004) u Ataru-Mauretaniji

The shortage of water resources in Adrar region, especially in Atar (Capital city of Adrar prefecture) and the surrounding villages along Seguelli watershed has been taken the concern of the policy maker and populations of this region since long time. This area had been suffering from recurrent droughts and faced water crises many times. Several attempts have been made to overcome these problems. Meanwhile the risk is still endangering the life and agricultural activities in one of the most important oasis areas. This study analyzed Atar rainfall time series periodicity, trends, and its relationship with Sea Surface Temperature (SST). The nonparametric Spearman test was used for trend analysis and the serial autocorrelation for persistency. Also, power spectrum and Fourier fit were deployed for analysis of frequency and periodicity. The tendency of Atar rainfall time series shows rainy periods in 1920’s and 1950’s and decreased rainfall since the late of 1950s. On the other hand, the prolonged drought periods appeared during 1970’s in contemporaneous with the Sahelian drought. The persistency analysis indicated the presence of biennial components in the annual and bimonthly rainfall in last three decades. SSTs of Atlantic, Indian and Pacific Ocean were modulating Atar rainfall during 1923–1992 period.U području Adrara, posebno u Ataru (glavnom gradu pokrajine Adrar) i okolnim selima duž Seguelli sliva proučavao se manjak vodenih resursa u odnosu na političke odnose i stanovništvo tog područja kroz duže vrijeme. To je područje karakterizirano čestim periodičnim sušama i nedostacima vode. Usprkos pokušajima da se taj problem prebrodi, život i poljoprivreda su i dalje ugroženi u jednoj od najvažnijih oaza u tom području. Ova studija analizira periodičnost vremenskog niza oborine u Ataru, trendove niza i njegov međuodnos s površinskom temperaturom mora. Pri analizi trenda koristio se neparametarski Spearman-ov test, dok je perzistencija analizirana putem autokorelacije. Također se koristio i spektar snage i harmonijska analiza za određivanje frekvencija i periodičnosti. Tendencija vremenskog niza oborina u Ataru pokazuje kišne periode u dvadesetim i pedesetim godinama 20. stoljeća i smanjenje oborine od kasnih pedesetih godina 20. stoljeća. Dugotrajni periodi suše pojavljuju se tijekom 70-tih istovremeno sa sušom u Sahelu. Analiza perzistencije ukazala je na postojanje dvogodišnjih komponenti u godišnjoj i dvomjesečnoj oborini u zadnje tri dekade. Površinske temperature mora Atlantika, Indijskog i Pacifičkog oceana utjecale su na količinu oborine u Ataru u razdoblju od 1923. do 1992. godine