Micro-size plankton abundance and assemblages in the western North Pacific Subtropical Gyre under microscopic observation

While primary productivity in the oligotrophic North Pacific Subtropical Gyre (NPSG) is changing, the micro-size plankton community has not been evaluated in the last 4 decades, prompting a re-evaluation. We collected samples over three years (2016–2018) from depths of 10 to 200 m (n = 127), and the micro-size plankton were identified and counted to understand the heterogeneity of micro-size plankton community structure. The assemblages were consistent to the those of 4 decades ago. Dinophyceae (dinoflagellates) were the most numerically abundant, followed by Cryptophyceae and Bacillariophyceae (diatoms). The other micro-size plankton classes (Cyanophyceae, Haptophyceae, Dictyochophyceae, Euglenophyceae, and Prasinophyceae) were not always detected, whereas only Trichodesmium spp. was counted in the Cyanophyceae. Other unidentified autotrophic and heterotrophic flagellates were also significantly present, and their numeric abundance was higher than or at the same level as was that of the Dinophyceae. In the Dinophyceae, Gymnodiniaceae and Peridiniales were abundant. The chlorophyll a concentration and these class-level assemblages suggested micro-size plankton is not a major primary producer in this area. We applied generalized additive models (GAMs) and principal coordination analyses (PCoAs) to evaluate the habitats of every plankton group and the heterogeneity of the assemblages. The GAMs suggested that every classified plankton abundance showed a similar response to salinity, and we observed differences in habitats in terms of temperature and nitrate concentrations. Based on the PCoAs, we observed unique communities at the 200 m depth layer compared with those at the other sampling layers. The site scores of PCoAs indicated that the micro-size plankton assemblages are most heterogeneous at the 10 m depth layer. At such depth, diazotrophic Cyanophyceae (Trichodesmium spp.) are abundant, particularly in less-saline water. Therefore, nitrogen fixation may contribute to the heterogeneity in the abundance and assemblages in the western NPSG.

Nitrogen-Vacancy Color Centers Created by Proton Implantation in a Diamond

We present an experimental study of the longitudinal and transverse relaxation of ensembles of negatively charged nitrogen-vacancy (NV−) centers in a diamond monocrystal prepared by 1.8 MeV proton implantation. The focused proton beam was used to introduce vacancies at a 20 µµm depth layer. Applied doses were in the range of 1.5×1013 to 1.5×1017 ions/cm2. The samples were subsequently annealed in vacuum which resulted in a migration of vacancies and their association with the nitrogen present in the diamond matrix. The proton implantation technique proved versatile to control production of nitrogen-vacancy color centers in thin films.

Pengaruh Kelas Kemiringan dan Posisi Lereng terhadap Ketebalan Lapisan Olah, Kandungan Bahan Organik, Al dan Fe pada Alfisol di Desa Gunungsari Kabupaten Tasikmalaya

ABSTRACTEffect of slope gradient and its position to plow depth layer, organic matter, Al and Fe contentsThis research was done to know the influence of slope gradient and its position to plow depth layer, organic matter, Al and Fe contents. This research was carried out January-March 2011. The research used survey method with descriptive comparative analysis with free physiographic approach based on land cover. Sampling technique was used a purposive stratified sampling. Soil sampel took from three slope gradients: 8-15%, 16-25% and 26-40% with three position of crest, middle and lower positions. The result showed that the gradient of slope and its position have influenced plow layer depth and content of iron but organic material and Al were not influenced. The highest of plow layer depth and content of iron were occured at 8-15%, while the highest of content of Al and iron were occured at 16-25 %. Based on slope position, the thick of plow layer, the content of organic matter, Fe wereoccured highest in the lower position and Al was occured in the middle position.Keywords: Slope, plow depth layer, organic matter, Al, FeABSTRAKPenelitian ini dilakukan untuk mengetahui adanya pengaruh dari kelas kemiringan dan posisi lereng terhadap ketebalan lapisan olah, bahan organik, Al dan Fe. Penelitian dilakukan pada bulan Januari-Maret 2011 dengan menggunakan metode survai dan analisis deskriptif komparatif melalui pendekatan fisiografis secara bebas berdasarkan penampakan fisiografis lahan. Teknik sampling berdasarkan metode sampel pertimbangan dalam stratifikasi. Contoh tanah diambil dari tiga kelas kemiringan lereng : 8-15%, 16-25% dan 26-40% dengan tiga posisi lereng yaitu posisi atas, posisi tengah dan posisi bawah. Hasil penelitian menunjukkan bahwa kemiringan dan posisi lereng berpengaruh terhadap ketebalan lapisan olah dan kandungan Fe sedangkan terhadap bahan organik dan kandungan Al tidak berpengaruh. Ketebalan lapisan olah dan bahan organik tertinggi dijumpai pada kemiringan lereng 8-15% sedangkan kandungan Al dan Fe tertinggi yaitu pada kemiringan lereng 16-25%. Berdasarkan posisi lerengnya, ketebalan lapisan olah, bahan organik, kandungan Fe tertinggi dijumpai pada posisi lereng bawah sedangkan kandungan Al pada posisi lereng tengah.Kata Kunci: Lereng, Ketebalan lapisan olah, Bahan organik, Al, Fe

POTENTIAL GEOLOGIC ISSUES OF VON KÁRMÁN CRATER REVEALED BY MULTISOURCE REMOTE SENSING DATA

<p><strong>Abstract.</strong> Von Kármán crater is the landing area for CE-4 mission, which provides a chance to further study the evolution of South-Pole Aitken basin. In this paper, the topography, composition, temperature and deep structures of Von Kármán crater are systematically studied with LRO LOLA data, Clementine UV-VIS data, CE-2 CELMS data, and GRAIL data. Several potential geologic issues are postulated as follows: (1) There exists a difference for the southern and northern parts of the crater floor in topography. The surface topography is influenced by Leibnitz and Finsen events. (2) There exists an FTA-rich material in depth layer of the crater floor, and the later bombardments exposed the original material in the crater floor. And the material in depth is homogeneous. (3) The composition apparently changes with depth, and there exist a warm anomaly in the northern part of the crater floor and a cold anomaly in the southern part. (4) A large amount of magma has been uplifted after Von Kármán M impact event, and the crust has been melted several times and condensed into dense basalt layer. Generally, this is a good place to measure the material from the original SPA basin and the material from the depth layer of the Moon for the CE-4 landing site.</p>

Pengaruh Kelas Kemiringan dan Posisi Lereng terhadap Ketebalan Lapisan Olah, Kandungan Bahan Organik, Al dan Fe pada Alfisol di Desa Gunungsari Kabupaten Tasikmalaya

ABSTRACTEffect of slope gradient and its position to plow depth layer, organic matter, Al and Fe contents in alfisol soil located at Gunungsari Village, Tasikmalaya RegencyThis research was done to know the influence of slope gradient and its position to plow depth layer, organic matter, Al and Fe contents. This research was carried out January-March 2011. Theresearch used survey method with descriptive comparative analysis with free physiographic approach based on land cover. Sampling technique was used a purposive stratified sampling. Soil sampel took from three slope gradients: 8-15%, 16-25% and 26-40% with three position of crest, middle and lower positions. The result showed that the gradient of slope and its position have influenced plow layer depth and content of iron but organic material and Al were not influenced. The highest of plow layer depth and content of iron were occured at 8-15%, while the highest of content of Al and iron were occured at 16-25 %. Based on slope position, the thick of plow layer, the content of organic matter, Fe were occured highest in the lower position and Al was occured in the middle position.Keywords: Slope, plow depth layer, organic matter, Al, FeABSTRAKPenelitian ini dilakukan untuk mengetahui adanya pengaruh dari kelas kemiringan dan posisi lereng terhadap ketebalan lapisan olah, bahan organik, Al dan Fe. Penelitian dilakukan pada bulan Januari-Maret 2011 dengan menggunakan metode survai dan analisis deskriptif komparatif melalui pendekatan fisiografis secara bebas berdasarkan penampakan fisiografis lahan. Teknik sampling berdasarkan metode sampel pertimbangan dalam stratifikasi. Contoh tanah diambil dari tiga kelas kemiringan lereng : 8-15%, 16-25% dan 26-40% dengan tiga posisi lereng yaitu posisi atas, posisi tengah dan posisi bawah. Hasil penelitian menunjukkan bahwa kemiringan dan posisi lereng berpengaruh terhadap ketebalan lapisan olah dan kandungan Fe sedangkan terhadap bahan organik dan kandungan Al tidak berpengaruh. Ketebalan lapisan olah dan bahan organik tertinggi dijumpai pada kemiringan lereng 8-15% sedangkan kandungan Al dan Fe tertinggi yaitu pada kemiringan lereng 16-25%. Berdasarkan posisi lerengnya, ketebalan lapisan olah, bahan organik, kandungan Fe tertinggi dijumpai pada posisi lereng bawah sedangkan kandungan Al pada posisi lereng tengah.Kata Kunci: Lereng, Ketebalan lapisan olah, Bahan organik, Al, Fe

Direct Depth SLAM: Sparse Geometric Feature Enhanced Direct Depth SLAM System for Low-Texture Environments

This paper presents a real-time, robust and low-drift depth-only SLAM (simultaneous localization and mapping) method for depth cameras by utilizing both dense range flow and sparse geometry features from sequential depth images. The proposed method is mainly composed of three optimization layers, namely Direct Depth layer, ICP (iterative closet point) Refined layer and Graph Optimization layer. The Direct Depth layer uses a range flow constraint equation to solve the fast 6-DOF (six degrees of freedom) frame-to-frame pose estimation problem. Then, the ICP Refined layer is used to reduce the local drift by applying local map based motion estimation strategy. After that, we propose a loop closure detection algorithm by extracting and matching sparse geometric features and construct a pose graph for the purpose of global pose optimization. We evaluate the performance of our method using benchmark datasets and real scene data. Experiment results show that our front-end algorithm clearly over performs the classic methods and our back-end algorithm is robust to find loop closures and reduce the global drift.