Selective Principal Component Extraction and Reconstruction: A Novel Method for Ground Based Exoplanet Spectroscopy

Context: Infrared spectroscopy of primary and secondary eclipse events probes the composition of exoplanet atmospheres and, using space telescopes, has detected H2O, CH4 and CO2 in three hot Jupiters. However, the available data from space telescopes has limited spectral resolution and does not cover the 2.4 - 5.2 micron spectral region. While large ground based telescopes have the potential to obtain molecular-abundance-grade spectra for many exoplanets, realizing this potential requires retrieving the astrophysical signal in the presence of large Earth-atmospheric and instrument systematic errors. Aims: Here we report a wavelet-assisted, selective principal component extraction method for ground based retrieval of the dayside spectrum of HD 189733b from data containing systematic errors. Methods: The method uses singular value decomposition and extracts those critical points of the Rayleigh quotient which correspond to the planet induced signal. The method does not require prior knowledge of the planet spectrum or the physical mechanisms causing systematic errors. Results: The spectrum obtained with our method is in excellent agreement with space based measurements made with HST and Spitzer (Swain et al. 2009b; Charbonneau et al. 2008) and confirms the recent ground based measurements (Swain et al. 2010) including the strong 3.3 micron emission.Comment: 4 pages, 3 figures; excepted for publication by A&

Transport and magnetic properties in YBaCo2O5.45: Focus on the high-temperature transition

The electronic transport properties and the magnetic susceptibility were measured in detail in $YBaCo_2O_{5.45}$. Close to the so-called metal-insulator transition, strong effects of resistance relaxation, a clear thermal hysteresis and a sudden increase of the resistance noise are observed. This is likely due to the first order character of the transition and to the underlying phases coexistence. Despite these out of equilibrium features, a positive and linear magneto-resistance is also observed, possibly linked to the heterogeneity of the state. From a magnetic point of view, the paramagnetic to ordered magnetic state transition is observed using non linear susceptibilty. This transition shows the characteristics of a continuous transition, and time dependent effects can be linked with the dynamics of magnetic domains in presence of disorder. Thus, when focusing on the order of the transitions, the electronic one and the magnetic one can not be directly associated.Comment: accepted for publication in PR

Ground-based NIR emission spectroscopy of HD189733b

We investigate the K and L band dayside emission of the hot-Jupiter HD 189733b with three nights of secondary eclipse data obtained with the SpeX instrument on the NASA IRTF. The observations for each of these three nights use equivalent instrument settings and the data from one of the nights has previously reported by Swain et al (2010). We describe an improved data analysis method that, in conjunction with the multi-night data set, allows increased spectral resolution (R~175) leading to high-confidence identification of spectral features. We confirm the previously reported strong emission at ~3.3 microns and, by assuming a 5% vibrational temperature excess for methane, we show that non-LTE emission from the methane nu3 branch is a physically plausible source of this emission. We consider two possible energy sources that could power non-LTE emission and additional modelling is needed to obtain a detailed understanding of the physics of the emission mechanism. The validity of the data analysis method and the presence of strong 3.3 microns emission is independently confirmed by simultaneous, long-slit, L band spectroscopy of HD 189733b and a comparison star.Comment: ApJ accepte

Reproductive ecology of the Mountain Dragon, Rankinia (Tympanocryptis) diemensis (Reptilia: Squamata: Agamidae) in Tasmania

The mountain dragon, Rankinta (7ympanocryptis) diemensis (Gray, 1841), is the only member of the Agamidae in Tasmania. It occurs in some of the coldest regions occupied by any dragon in Australia, and is found in a variety of habitats ranging from coastal heath to alpine scrub. This paper examines the reproductive ecology of R. diemensis in the most southerly range of its distribution, providing baseline data on timing of reproductive events, reproductive cycles, nesting behaviour and ovipositioning, clutch characteristics and incubation conditions. Winter torpor lasts approximately seven months with males emerging in early September and spermatogenesis occurring from September-November. Females emerge later, with vitellogenesis occurring from September-December. Gravid females may be found between October and January, but females are non-vitellogenic from late December until the following season. The first clutch is typically laid from October--December, with a variable clutch size (2-11 eggs). Females store sperm and a second clutch may be laid five weeks after the first. Eggs incubated in artificial enclosures at low altitude hatched after 72--106 days, after experiencing an average daily temperature of 19°-22°C, and a range of 50-39°C

Fatigue crack initiation and small crack growth in several airframe alloys

The growth of naturally-initiated small cracks under a variety of constant amplitude and variable amplitude load sequences is examined for several airframe materials: the conventional aluminum alloys, 2024-T3 and 7075-T6, the aluminum-lithium alloy, 2090-T8E41, and 4340 steel. Loading conditions investigated include constant amplitude loading at R = 0.5, 0, -1 and -2 and the variable amplitude sequences FALSTAFF, Mini-TWIST and FELIX/28. Crack growth was measured at the root of semicircular edge notches using acetate replicas. Crack growth rates are compared on a stress intensity factor basis, to those for large cracks to evaluate the extent of the small crack effect in each alloy. In addition, the various alloys are compared on a crack initiation and crack growth morphology basis

Electric Dipole Moments and Polarizability in the Quark-Diquark Model of the Neutron

For a bound state internal wave function respecting parity symmetry, it can be rigorously argued that the mean electric dipole moment must be strictly zero. Thus, both the neutron, viewed as a bound state of three quarks, and the water molecule, viewed as a bound state of ten electrons two protons and an oxygen nucleus, both have zero mean electric dipole moments. Yet, the water molecule is said to have a nonzero dipole moment strength $d=e\Lambda$ with $\Lambda_{H_2O} \approx 0.385\ \dot{A}$. The neutron may also be said to have an electric dipole moment strength with $\Lambda_{neutron} \approx 0.612\ fm$. The neutron analysis can be made experimentally consistent, if one employs a quark-diquark model of neutron structure.Comment: four pages, two figure

Influence of the Static Screen Inclination on the Effect-ive Separating Size and Concentration of Beach Sand Minerals

In this paper an attempt has been made to evaluate the effect of inclination of micro screen on the effective separating size of beach sand minerals. The results of these investigations indicate that the cut sizes of 130pm, 122pm, 63pm, 55pm and 40pm could be obtained from a feed containing —1mm size range with a variable deck inclina-tion such as 35°, 40°, 67°, 70° and 75° respectively. The cut sizes are evaluated based on the partition curve according to Tromp. The typical size analysis data obtained at cut size of 63pm, indicate that the overflow and +300pm size fraction of the under flow contain rejec-table tailings amounting to 51% by weight with overall heavies loss contain 4.7%, Thus micro screen is effective for dual purpose such as classifications like hydrocyclone and preconcentration like a spiral concentrator. Hence, it can be concluded that the micro screen is not only an effective for classification at different cut points but also can work as a good preconcentrator for beach sands