Pengaruh Intensitas Cahaya Terhadap Pertumbuhan Dan Konten Rantai Panjang Polyisoprenoid Pada Mangrove Sejati Mayor Berjenis Sekresi Sonneratia Caseolaris (L.)

Each plant species has a different response to the light intensity. Some species need shade in the early growth, and there are species did not require shade in the early growth. Mangrove degradation have been occurred for recent years, rehabilition program therefore are needed for reforestation. The reforestation needs a superior and qualified seeds for the best growth. This study focus on S. caseolaris because this fruit species priority consumed by local people in the area of mangrove and for rehabilitation program. The applied research method is Complete Random Sampling, non factorial that consist of different repetition. The applied analysis method is variance analysis with advanced tesdt by determining the value that influence or not with Dunnet method on confidential level 5% with 4 treatments for light intensity 100%, 75%, 50% and 25%. This research was conducted at Pharmacy Laboratory and Faculty of Agriculture, Department of Forestry of University of Sumatera Utara since July of 2014 to January of 2015. The results of research indicates that the light intensity 50% showed best growth of morphology and polyisoprenoid content is not found in S. caseolaris because the dried weight is not sufficient for further analysis

Photometry of the Oort Cloud comet C/2009 P1(Garradd): pre-perihelion observations at 5.7 and 2.5 AU

The aim of this paper is to contribute to the characterization of the general properties of the Long Period Comets (LPCs) family, and in particular to report on the dust environment of comet C/2009 P1 (Garradd). The comet was observed at two epochs pre-perihelion, at ~6 AU and at ~2.5 AU: broad-band images have been used to investigate its coma morphology and properties and to model the dust production rate. Comet C/2009 P1 (Garradd) is one of the most active and “dust producing” LPCs ever observed, even at the large heliocentric distance rh~6 AU. Its coma presents a complex morphology, with subtle structures underlying the classical fan-shaped tail, and, at rh~2.5 AU, also jet-like structures and spiralling outflows. In the reference aperture of radius ρ=5°×104 km, the R-Afρ is 3693±156 cm and 6368±412 cm, in August 2010 (rh~6 AU) and July 2011 (rh~2.5 AU), respectively. The application of a first order photometric model, under realistic assumptions on grain geometric albedo, power-law dust size distribution, phase darkening function and grain dust outflow velocity, yielded a measure of the dust production rate for the two epochs of observation of Qd=7.27×102 kg/s and Qd=1.37×103 kg/s, respectively, for a reference outflow dust velocity of vsmall=25 m/s for small (0.1–10 µm) grains and vlarge=1 m/s for large (10 µm–1 cm) grains. These results suggest that comet Garradd is one of the most active minor bodies observed in recent years, highly contributing to the continuous replenishment of the Interplanetary Dust Complex also in the outer Solar System, and pose important constraints on the mechanism(s) driving the cometary activity at large heliocentric distances

Synthesis and gas-sensing properties of pd-doped SnO2 nanocrystals. A case study of a general methodology for doping metal oxide nanocrystals

Pd-modified SnO2 nanocrystals, with a Pd/Sn nominal atomic ratio of 0.025, were prepared by injecting SnO2 sols and a Pd precursor solution into tetradecene and dodecylamine at 160 degrees C. Two different doping procedures were investigated: in co-injection, a Pd acetylacetonate solution in chloroform was mixed with the SnO2 sol before the injection; in sequential injection, the Pd solution was injected separately after the SnO2 sol. The obtained suspensions were heated at the resulting 80 degrees C temperature, then the product was collected by centrifugation and dried at 80 degrees C. When using co-injection, in the dried products PdO and Pd nanoparticles were observed by high-resolution transmission electron microscopy. Only SnO2 nanocrystals were observed in dried products prepared by sequential injection. After heat-treatment at 500 degrees C, no Pd species were observed for both doping procedures. Moreover, X-ray photoelectron spectroscopy showed that, in both the doping procedures, after heat-treatment Pd is distributed only into the SnO2 nanocrystal structure. This conclusion was reinforced by the measurement of the electrical properties of Pd-doped nanocrystals, showing a remarkable increase of the electrical resistance if compared with pure SnO2 nanocrystals. This result was interpreted as Pd insertion as a dopant inside the cassiterite lattice of tin dioxide. The addition of Pd resulted in a remarkable improvement of the gas-sensing properties, allowing the detection of carbon monoxide concentrations below 50 ppm and of very low concentrations (below 25 ppm) of other reducing gases such as ethanol and acetone

GIADA performance during Rosetta mission scientific operations at comet 67P

The Grain Impact Analyser and Dust Accumulator (GIADA) instrument onboard Rosetta studied the dust environment of comet 67P/Churyumov–Gerasimenko from 3.7 au inbound, through perihelion, to 3.8 au outbound, measuring the dust flow and the dynamic properties of individual particles. GIADA is composed of three subsystems: 1) Grain Detection System (GDS); 2) Impact Sensor (IS); and 3) Micro-Balances System (MBS). Monitoring the subsystems’ performance during operations is an important element for the correct calibration of scientific measurements. In this paper, we analyse the GIADA inflight calibration data obtained by internal calibration devices for the three subsystems during the period from 1 August 2014 to 31 October 2015. The calibration data testify a nominal behaviour of the instrument during these fifteen months of mission; the only exception is a minor loss of sensitivity for one of the two GDS receivers, attributed to dust contamination

The NEOShield-2 EU project: The Italian contribution

The NEOShield-2 (2015-2017) project has been recently approved by the European Commission in the framework of the Horizon 2020 programme with the aim i) to study specific technologies and instruments to conduct close approach missions to NEOs or to undertake mitigation demonstration, and ii) to acquire in-depth information of physical properties of the population of small NEOs (50-300 m), in order to design mitigation missions and assess the consequences of an impact on Earth. The Italian scientific community is widely involved in this project

Photometric survey of 67 near-Earth objects

Context. The near-Earth object (NEO) population is a window into the original conditions of the protosolar nebula, and has the potential to provide a key pathway for the delivery of water and organics to the early Earth. In addition to delivering the crucial ingredients for life, NEOs can pose a serious hazard to humanity since they can impact the Earth. To properly quantify the impact risk, physical properties of the NEO population need to be studied. Unfortunately, NEOs have a great variation in terms of mitigation-relevant quantities (size, albedo, composition, etc.) and less than 15% of them have been characterized to date. Aims. There is an urgent need to undertake a comprehensive characterization of smaller NEOs (D < 300 m) given that there are many more of them than larger objects; their small sizes make them intrinsically fainter and therefore harder to study. One of the main aims of the NEOShield-2 project (2015-2017), financed by the European Community in the framework of the Horizon 2020 program, is therefore to retrieve physical properties of a wide number of NEOs in order to design impact mitigation missions and assess the consequences of an impact on Earth. Methods. We carried out visible photometry of NEOs, making use of the DOLORES instrument at the Telescopio Nazionale Galileo (TNG, La Palma, Spain) in order to derive visible color indexes and the taxonomic classification for each target in our sample. Results. We attributed for the first time the taxonomical complex of 67 objects obtained during the first year of the project. While the majority of our sample belong to the S-complex, carbonaceous C-complex NEOs deserve particular attention. These NEOs can be located in orbits that are challenging from a mitigation point of view, with high inclination and low minimum orbit intersection distance (MOID). In addition, the lack of carbonaceous material we see in the small NEO population might not be due to an observational bias alone

Characterisation of the main belt asteroid (223) Rosa: A proposed flyby target of ESA's JUICE mission

Context. The ESA JUICE space mission, on its way to study Jupiter's environment and icy moons, will pass twice through the main asteroid belt. For this reason, the possibility to perform an asteroid flyby has been investigated. Aims. We aim to gain insight into the physical properties of the outer main belt asteroid (223) Rosa, which has been proposed as a potential JUICE flyby target. Methods. We report new visible and near-infrared spectroscopic observations at different rotation phases. Additionally, we perform a literature review of all the available physical properties, such as diameter, albedo, mass, and rotational period. Results. We find that asteroid Rosa is an X-type asteroid that shows no significant spectral variability combining the new and literature spectroscopic data. Its large size and orbital semimajor axis in the outer main belt indicate that Rosa does not belong to the Themis family, while its albedo is only marginally compatible with the family. Rosa's estimated density is in agreement with those of other low-albedo X-type asteroids. Hence, we propose that Rosa is a planetesimal that accreted in the protoplanetary disk beyond the snow line

Planning the HRIC (High Resolution Imaging Channel) observations of Mercury surface

The High Resolution Imaging Channel (HRIC) of SIMBIOSYS [1]onboard the BepiColombo mission to Mercury, is the visible imaging camera devoted to the detailed characterization of the Hermean surface. The potential huge amount of data that HRIC can produce must cope with the allocated (and shared) mission resources in terms of power, data volume,and pointing maneuvers. For this reason , well before the mission launch, it is extremely important the definition of an operative plan compatible with both the available resources and the scientific objectives accomplishment