A comparison of leaf crystal macropatterns in the two sister genera Piper and Peperomia (Piperaceae)

Premise of the study: This is the first large-scale study comparing leaf crystal macropatterns of the species-rich sister genera Piper and Peperomia. It focuses on identifying types of calcium oxalate crystals and their macropatterns in leaves of both genera. The Piper results are placed in a phylogenetic context to show evolutionary patterns. This information will expand knowledge about crystals and provide specific examples to help study their form and function. One example is the first-time observation of Piper crystal sand tumbling in chlorenchyma vacuoles. Methods: Herbarium and fresh leaves were cleared of cytoplasmic content and examined with polarizing microscopy to identify types of crystals and their macropatterns. Selected hydrated herbarium and fresh leaf punches were processed for scanning electron microscopy and x-ray elemental analysis. Vibratome sections of living Piper and Peperomia leaves were observed for anatomical features and crystal movement. Key results: Both genera have different leaf anatomies. Piper displays four crystal types in chlorenchyma-crystal sand, raphides, styloids, and druses, whereas Peperomia displays three types-druses, raphides, and prisms. Because of different leaf anatomies and crystal types between the genera, macropatterns are completely different. Crystal macropattern evolution in both is characterized by increasing complexity, and both may use their crystals for light gathering and reflection for efficient photosynthesis under low-intensity light environments. Conclusions: Both genera have different leaf anatomies, types of crystals and crystal macropatterns. Based on Piper crystals associated with photosynthetic tissues and low-intensity light, further study of their function and association with surrounding chloroplasts is warranted, especially active crystal movement

compte rendu d'ouvrage: Persyn-Vialard, Sandrine, La linguistique de Karl Bühler, Examen critique de la Sprachtheorie et de sa filiation

Histoire Epistémologie Langage, 30, 1, 163-165compte rendu de: Persyn-Vialard, Sandrine, La linguistique de Karl Bühler, Examen critique de la Sprachtheorie et de sa filiation, Presses Universitaires de Rennes, 2005, 280 p., ISBN 2-7535- 0149-1

SFGP 2007 - Investigation of a Novel Principle of Chemical Grafting for Modification of Cellulose Fibers

Natural cellulose fibres have been employed for packaging applications for a long time. Their use, however, has been hampered by their high hydrophilicity and their moisture sensitivity. It has, thus, been proposed to circumvent this problem through the hydrophobic modification of their surface thanks to the use of molecular grafting approaches. In this work, we describe the use of a novel solvent-free chemical pathway for molecular grafting that we have coined chromatogenic chemistry. It involves a reaction between a solid substrate and a reagent which is in a vapour-liquid equilibrium and diffuses within the solid substrate through a mechanism of adsorption/desorption akin to gas chromatography. Chromatogenic chemistry phenomenon has been studied and modelled through the extensive use of a new specific test, the Droplet Surface Migration Test. It involves the deposition upon a porous substrate of a small amount of reagent and in studying its subsequent migration and grafting. Whatman paper and various long chain acid chlorides were used for this modelling. The acid chloride carboxylic ends react with the external hydroxyl groups of cellulose fibres to give rise to the formation of long chain hydrophobic ester bonds. Upon immersion of the paper sheet in distilled water, a hydrophobic spot, extending well over the initial depot zone, could then be clearly visualized, allowing to follow conveniently the reagent migration and reaction. Grafting densities were performed by using the HPLC technique. The results obtained through the use of this test allowed a better understanding of chromatogenic chemistry phenomenon and an identification of the main parameters which affect the process: the nature of the reagent, the temperature, the reaction time, the nature of the substrate, etc. We have more particularly shown that the diffusion and grafting yields were maximal for a specific temperature which increases with the boiling point and therefore with the chain length of the reagents. We have proposed that this temperature should correspond to a compromise between the diffusion and reactivity properties of the reagent, its evaporation and its degradation by hydrolysis

KONSEP KESEHATAN MENTAL DALAM AL-QUR’ĀN DAN IMPLIKASINYA TERHADAP ADVERSITY QUOTIENT PERSPEKTIF TAFSIR AL-MISBAH

The objectives of this paper are: (1) How is the concept of mental health in the Qur'an, (2) How is the view of the Qur'ān about psychotherapy on mental health disorders. (3) What are the implications of the concept of al-Qur'ān on mental health against the attitude of the Adversity Quotient from the perspective of Al-Misbah's interpretation. This research is a qualitative study using the theoretical method of text hermeneutics. The results of this study indicate that the al-Qur'ān contains spiritual values so that it can overcome the difficulties of human life. The view of al-Qur'ān about psychotherapy is a model of healing with rukyah in accordance with the surah Al Isra '(17): 82. The essential implications of adversity Quotient Mental health contained in al-Qur'ān surah al-Baqarah (2): 153; al-Baqarah (2): 155; and Adz Dariyat: 56. These verses contain strong values and motivation for adversity quotient, namely patience and optimism. The results of this study are expected to be able to reconstruct a human perspective and a healthy mentality in facing life's problems so that they have a high Adversity Quotient and are not easily discouraged, resilient, abstinence and not easy to commit suicide.Keywords: Mental Health, Adversity Quotient, Tafsir Al Misba

Consistency between hydrological model, large aperture scintillometer and remote sensing based evapotranspiration estimates for a heterogeneous catchment

The catchment averaged actual evapotranspiration rate is a hydrologic model variable that is difficult to quantify. Evapotranspiration rates - up till present - cannot be continuously observed at the catchment scale. The objective of this paper is to estimate the evapotranspiration rates (or its energy equivalent, the latent heat fluxes LE) for a heterogeneous catchment of 102.3 km(2) in Belgium using three fundamentally different algorithms. One possible manner to observe this variable could be the continuous measurement of sensible heat fluxes (H) across large distances (in the order of kilometers) using a large aperture scintillometer (LAS), and converting these observations into evapotranspiration rates. Latent heat fluxes are obtained through the energy balance equation using a series of sensible heat fluxes measured with a LAS over a distance of 9.5 km in the catchment, and point measurements of net radiation (R-n) and ground heat flux (G) upscaled to catchment average through the use of TOPLATS, a physically based land surface model. The resulting LE-values are then compared to results from the remote sensing based surface energy balance algorithm ETLook and the land surface model. Firstly, the performance of ETLook for the energy balance terms has been assessed at the point scale and at the catchment scale. Secondly, consistency between daily evapotranspiration rates from ETLook, TOPLATS and LAS is shown

Verhuellia is a segregate lineage in Piperaceae: more evidence from flower, fruit and pollen morphology, anatomy and development

Background and Aims The perianthless Piperales, i.e. Saururaceae and Piperaceae, have simple reduced flowers strikingly different from the other families of the order (e.g. Aristolochiaceae). Recent molecular phylogenies proved Verhuellia to be the first branch in Piperaceae, making it a promising object to study the detailed structure and development of the flowers. Based on recently collected material, the first detailed study since 1872 was conducted with respect to morphology, anatomy and development of the inflorescence, pollen ultrastructure and fruit anatomy. Methods Original Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Light Microscopy (LM) observations on Verhuellia lunaria were compared with Piperaceae, Saururaceae and fossils. Key results The inflorescence is an indeterminate spike with sessile flowers, each in the axil of a bract, developing in acropetal, helical succession. Flowers consist of two (occasionally three) stamens with basifixed tetrasporangiate anthers and latrorse dehiscence by a longitudinal slit. The gynoecium lacks a style but has three to four stigma branches and a single, basal orthotropous, and unitegmic ovule. The fruit is a drupe with large multicellular epidermal protuberances. The pollen is very small, inaperturate, and areolate with hemispherical microechinate exine elements. Conclusions Despite the superficial similarities with different genera of Piperaceae and Saururaceae, the segregate position of Verhuellia revealed by molecular phylogenetics is supported by morphological, developmental and anatomical data presented here. Unitegmic ovules and inaperturate pollen, which are synapomorphies for the genus Peperomia, are also present in Verhuellia

METHOD FOR FAST BOOTSTRAP AND LOSS RECOVERY FOR CLIENTS CONNECTED TO A SELECTIVE FORWARDING UNIT (SFU)

Proposed herein is a technique to reduce the time to obtain an I-frame for video conferencing participants that are unable to decode video stream(s) of the main active speaker(s) by decoding video stream(s) of the main active speaker(s) at a Selective Forwarding Unit (SFU) and re-encoding the video stream(s) using only I-frames. The technique also provides for the ability reduce network traffic by unicasting the I-frames only to participants that may need the I-frames, rather than broadcasting the I-frames to all participants

A New Application of the Lunar Laser Retroreflectors: Searching for the "Local" Hubble Expansion

Precise measurements of the Earth-Moon distance by the lunar laser ranging (LLR), which begun in the early 1970's, contributed significantly to geodesy, geophysics, and lunar planetology, as well as enabled astrophysicists to perform several fine tests of the relativistic gravitational field theory (General Relativity). Yet another promising application of LLR arises just now in the context of recent cosmological models, whose dynamics is substantially affected by some kinds of the dark matter (or the so-called "dark energy") uniformly distributed in space, and therefore should be accompanied by some residual Hubble expansion at any spatial scales, particularly, in the Earth-Moon system. The "local" Hubble expansion can be revealed by comparing the rate of increase in the lunar semi-major axis measured by LLR (which should be produced both by the well-known tidal exchange of angular momentum between the Earth and Moon and the local Hubble expansion) with the same quantity derived indirectly from astrometric data on the Earth's rotation deceleration (which is produced only by the tidal interaction). Such analysis really points to the discrepancy 1.3 cm/yr, which corresponds to the local Hubble constant H_0^(loc) = 33 +/- 5 (km/s)/Mpc. This value is about two times less than at intergalactic scales but many orders of magnitude greater than was predicted in earlier theoretical works.Comment: Single PS file, 6 pages, submitted to "Advances in Space Research". Substantial new explanations, requested by the reviewers', were introduced; minor misprints were correcte