Wavelet Reconstruction of Nonuniformly Sampled Signals

For the reconstruction of a nonuniformly sampled signal based on its noisy observations, we propose a level dependent l1 penalized wavelet reconstruction method. The LARS/Lasso algorithm is applied to solve the Lasso problem. The data adaptive choice of the regularization parameters is based on the AIC and the degrees of freedom is estimated by the number of nonzero elements in the Lasso solution. Simulation results conducted on some commonly used 1_D test signals illustrate that the proposed method possesses good empirical properties

Tunable variation of optical properties of polymer capped gold nanoparticles

Optical properties of polymer capped gold nanoparticles of various sizes (diameter 3-6 nm) have been studied. We present a new scheme to extract size dependent variation of total dielectric function of gold nanoparticles from measured UV-Vis absorption data. The new scheme can also be used, in principle, for other related systems as well. We show how quantum effect, surface atomic co - ordination and polymer - nanoparticle interface morphology leads to a systematic variation in inter band part of the dielectric function of gold nanoparticles, obtained from the analysis using our new scheme. Careful analysis enables identification of the possible changes to the electronic band structure in such nanoparticles.Comment: 13 pages,7 figures, 1 tabl

Bronze Age cooking pots: Thermal properties and cooking methods

This paper examines the interplay between manufacturing parameters and material properties in archaeological ceramic cooking ware. While previous studies on material properties have focused on the response of ceramic vessels to mechanical and thermal loads, emphasis is placed here on thermal properties and their influence on the suitability of a vessel to be used for different cooking methods. We illustrate how the material properties of a ceramic cooking vessel are influenced by its manufacture and how these material properties in turn may influence the performance and ultimately selection of certain vessels to be used for specific cooking practices for the example of late Bronze Age (LCIA) cooking vessels from Akrotiri, Greece.Cet article examine l’alternance entre les paramètres de la fabrication et les propriétés des matériaux des ustensiles en céramique archéologiques servant à la cuisson. Tandis que les études préalables concernant les vaisseaux en céramique étaient axées sur leur réaction aux contraintes mécaniques et thermiques, l’accent ici est mis sur les propriétés thermiques et leur influence sur l’aptitude d’un vaisseau en vue des différentes méthodes de cuisson. Nous montrons comment les propriétés des matériaux d’un vaisseau sont influencées par sa fabrication et de quelle manière enfin ces propriétés des matériaux peuvent influencer à leur tour la sélection de certains vaisseaux quant aux méthodes spécifiques de cuisson, exemple : les vaisseaux de cuisson d’Akrotiri, Grèce, datant de l’âge du Bronze final

Bronze Age cooking pots: Thermal properties and cooking methods

This paper examines the interplay between manufacturing parameters and material properties in archaeological ceramic cooking ware. While previous studies on material properties have focused on the response of ceramic vessels to mechanical and thermal loads, emphasis is placed here on thermal properties and their influence on the suitability of a vessel to be used for different cooking methods. We illustrate how the material properties of a ceramic cooking vessel are influenced by its manufacture and how these material properties in turn may influence the performance and ultimately selection of certain vessels to be used for specific cooking practices for the example of late Bronze Age (LCIA) cooking vessels from Akrotiri, Greece.Cet article examine l’alternance entre les paramètres de la fabrication et les propriétés des matériaux des ustensiles en céramique archéologiques servant à la cuisson. Tandis que les études préalables concernant les vaisseaux en céramique étaient axées sur leur réaction aux contraintes mécaniques et thermiques, l’accent ici est mis sur les propriétés thermiques et leur influence sur l’aptitude d’un vaisseau en vue des différentes méthodes de cuisson. Nous montrons comment les propriétés des matériaux d’un vaisseau sont influencées par sa fabrication et de quelle manière enfin ces propriétés des matériaux peuvent influencer à leur tour la sélection de certains vaisseaux quant aux méthodes spécifiques de cuisson, exemple : les vaisseaux de cuisson d’Akrotiri, Grèce, datant de l’âge du Bronze final

Inversion for Non-Smooth Models with Physical Bounds

Geological processes produce structures at multiple scales. A discontinuity in the subsurface can occur due to layering, tectonic activities such as faulting, folding and fractures. Traditional approaches to invert geophysical data employ smoothness constraints. Such methods produce smooth models and thefore sharp contrasts in the medium such as lithological boundaries are not easily discernible. The methods that are able to produce non-smooth models, can help interpret the geological discontinuity. In this paper we examine various approaches to obtain non-smooth models from a finite set of noisy data. Broadly they can be categorized into approaches: (1) imposing non-smooth regularization in the inverse problem and (2) solve the inverse problem in a domain that provides multi-scale resolution, such as wavelet domain. In addition to applying non-smooth constraints, we further constrain the inverse problem to obtain models within prescribed physical bounds. The optimization with non-smooth regularization and physical bounds is solved using an interior point method. We demonstrate the applicability and usefulness of these methods with realistic synthetic examples and provide a field example from crosswell radar data

Caractérisation pathologique in vitro de deightoniella torulosa (Syd.) Ellis sur les cultivars de bananiers figue sucrée (musa AA), grande naine (musa AAA) et orishele (musa AAB)

Deightoniella torulosa est un champignon fréquemment associé aux attaques des cercosporioses sur les principaux cultivars de bananier en Côte-d\'Ivoire. Les symptômes qu\'il induit sont mal connus et les attaques occasionnées en plantation sont négligées. Le champignon a été isolé et son pouvoir pathogène a été mis en évidence sur des fragments de feuilles et des feuilles entières de différents cultivars de bananiers en utilisant différentes concentrations de spores : à 104, 5.104 et 105 spores / ml. Des coupes histologiques ont été aussi réalisées. Les résultats ont mis en évidence l\'activité parasitaire du champignon sur les fragments de feuilles et sur les feuilles entières. La période d\'incubation est de 3 à 5 jours. La germination des spores débute en moins d\'une heure et atteint 95 à 100 % au bout de 4 heures. L\'évolution des symptômes varie en fonction des cultivars. L\'ampleur des attaques s\'est révélée importante lorsque les concentrations de spores sont élevées. Le champignon provoque des attaques sévères pour des concentrations de 105 spores / ml. Ainsi, Deightoniella torulosa induit seul des attaques, colonise les tissus du limbe foliaire et contribue à la sénescence prématurée des feuilles de bananiers.Deightoniella torulosa is a fungus usually associated with symptoms of black sigatoka leaf streak in Côte-d\'Ivoire. The pathogenic activity of the fungus is not well known and its effect on field is neglected. The fungus has been isolated and its pathogenic activity has been determined on leaves of cultivated banana through the use of different concentrations of conidia: 104, 5.104 and 105 spores / ml. Inoculated samples have been fixed for histological observations. Results showed stomata penetration and pathogenic activity of fungus beginning from the third (3rd) to the fifth (5th) day after inoculation. We observed that conidia germination begins in less than 1 hour and reaches 95 to 100 % within 4 hours. The progress of the disease varies according to the according to the banana cultivars and the amount of conidia. 105 spores / ml have induced symptoms. Then, Deightoniella torulosa alone could induce symptoms and was involved in rapid necrosis of infected leaves in natural conditions. Keywords: Deightoniella torulosa, activité parasitaire, inoculations, cultivars de bananiers, sénescence, Côte-d\'Ivoire./Deightoniella torulosa, pathogenic activity, inoculations, cultivated banana, Côte-d\'Ivoire.Sciences & Nature Vol. 4 (2) 2007: pp. 179-18

PEMETAAN KONDISI FISIK DASAR WILAYAH BERBASIS SISTEM INFORMASI GEOGRAFIS (SIG) DI NEGERI TAWIRI KECAMATAN TELUK AMBON

Perencanaan suatu daerah atau pembangun sebuah kawasan berkelanjutan perlu memperhatikan aspek fisik dasar suatu wilayah. Pemahaman keadaan topografi, geologi (kerawanan bencana) dan geofisika (kemiringan lereng) wilayah sangat diperlukan dalam proses pembangunan. Sistem Informasi Geografis (SIG) menjadi salah satu sarana untuk mendapatkan informasi geografis secara cepat, tepat, dan akurat mengenai data tersebut. Tujuan dari PKM ini adalah untuk mengedukasi masyarakat negeri Tawiri untuk dapat memetakan sebuah kawasan secara baik. Kegiatan PKM ini melibatkan pemerintah Negeri Tawiri dan beberapa tokoh masyarakat. Metode yang digunakan dalam kegiatan ini adalah metode diskusi terpusat. Hasil dari kegiatan ini adalah rumusan arah kebijakan terkait pembangunan Negeri Tawiri berdasarkan kondisi fisik wilayah berupa pemetaan topografi, kemiringan lereng dan kerawanan bencana tanah longsor. Peta ini disusun dan dicetak, kemudian diserahkan kepada pemerintah Negeri Tawiri secara simbolis. Peta ini sangat penting untuk menjadi bahan pertimbangan dalam pengambilan keputusan di dalam pembangunan dan mitigasi bencana Negeri Tawiri di masa yang akan datang

Low thermal conductivity of the layered oxide (Na,Ca)Co_2O_4: Another example of a phonon glass and an electron crystal

The thermal conductivity of polycrystalline samples of (Na,Ca)Co_2O_4 is found to be unusually low, 20 mW/cmK at 280 K. On the assumption of the Wiedemann-Franz law, the lattice thermal conductivity is estimated to be 18 mW/cmK at 280 K, and it does not change appreciably with the substitution of Ca for Na. A quantitative analysis has revealed that the phonon mean free path is comparable with the lattice parameters, where the point-defect scattering plays an important role. Electronically the same samples show a metallic conduction down to 4.2 K, which strongly suggests that NaCo_2O_4 exhibits a glass-like poor thermal conduction together with a metal-like good electrical conduction. The present study further suggests that a strongly correlated system with layered structure can act as a material of a phonon glass and an electron crystal.Comment: 5 pages 3 figures, to be published in Phys. Rev.

Direct and plant community mediated effects of management intensity on annual nutrient leaching risk in temperate grasslands

Grassland management intensity influences nutrient cycling both directly, by changing nutrient inputs and outputs from the ecosystem, and indirectly, by altering the nutrient content, and the diversity and functional composition of plant and microbial communities. However, the relative importance of these direct and indirect processes for the leaching of multiple nutrients is poorly studied. We measured the annual leaching of nitrate, ammonium, phosphate and sulphate at a depth of 10 cm in 150 temperate managed grasslands using a resin method. Using Structural Equation Modeling, we distinguished between various direct and indirect effects of management intensity (i.e. grazing and fertilization) on nutrient leaching. We found that management intensity was positively associated with nitrate, ammonium and phosphate leaching risk both directly (i.e. via increased nutrient inputs) and indirectly, by changing the stoichiometry of soils, plants and microbes. In contrast, sulphate leaching risk was negatively associated with management intensity, presumably due to increased outputs with mowing and grazing. In addition, management intensification shifted plant communities towards an exploitative functional composition (characterized by high tissue turnover rates) and, thus, further promoted the leaching risk of inorganic nitrogen. Plant species richness was associated with lower inorganic nitrogen leaching risk, but most of its effects were mediated by stoichiometry and plant community functional traits. Maintaining and restoring diverse plant communities may therefore mitigate the increased leaching risk that management intensity imposes upon grasslands