Investigation of Factors Influencing the Occurrence of 3C-Inclusions for the Thick Growth of on-Axis C-Face 4H-SiC Epitaxial Layers

In this study, we grew homoepitaxial layers on 3-inch on-axis carbon-face 4H-silicon carbide substrates and attempted to suppress the generation of 3C-inclusions. It was found that the 3C-inclusion density decreased with increasing time spent on reaching an objective flow rate for the precursors. It is suggested that 3C-SiC nucleation occurred on large terraces of the on-axis substrates, which existed before the substrates were covered with spiral hillocks. This nucleation was suppressed owing to the decrease in the degree of supersaturation at the initial growth stage. Moreover, we found that the 3C-inclusions were also generated owing to contamination in the form of graphite products. Furthermore, we succeeded in growing a thick on-axis 4H-SiC homoepitaxial layer on a 3-inch substrate and demonstrating its free-standing epitaxial layer with a thickness of 182 μm and a 3C-inclusion density of 2.0 cm−2.

Gas Exchange and Photochemical Efficiency of Caatinga Plants Submitted to Different Water Management Strategies

Water availability is a critical point for dryland recovered on tropical regions of the world. This problem to become higher with the lacking information about the ecophysiologial behavior of the native plants on the initial growth stage under field conditions, mainly when these plants are submitted to different water availability levels. To address this question, we evaluated different water management strategies on the ecophysiological features of the five young native plants establishment in a degraded area located in the Caatinga, a dryland Brazilian forest. The water management strategies effects on native plants were checked by analyzing the photosynthesis rates, gas exchange and photochemistry efficiency in leaves of Crataeva tapia, Erythrina mulungu, Handroanthus impetiginosus, Tabebuia aurea and Ziziphus joazeiro. The experiment had four treatments (waterbox use, bovine manure, hydrogel, bovine manure plus hydrogel) and control. In the initial growth stage and under field conditions, the effects of water stress or water deficiency on the photosynthetic rates, gas exchange and chlorophyll fluorescence a of the T. aurea, H. impetiginosus, C. tapia and E. mulungu, exposed to waterbox and hydrogel, associated or not with bovine manure, were partially or totally mitigated. The Z. joazeiro species has the adaptive intrinsic characteristics that allow them to with stand the most stressful environmental conditions and this naturally allowed presenting greater water use efficiency and absence of damage to the photosynthetic apparatus and high Fv/Fm ratio. In general, the water management strategies studied have alleviated the effects of water stress, totally or partially, on the ecophysiological processes of young native plants under field conditions.

Perkembangan sel telur ikan seriding, Ambassis nalua (Hamilton 1822) [Oocyte development of scalloped perchlet, Ambassis nalua (Hamilton 1822)]

Scalloped perchlet (Ambassis nalua) is a small, transparent, and abundant species inhabit in Pabean Bay, Indramayu. The present study aims to describes oosit development stages histologically and determine the spawning type of the Scalloped perchlet. Scalloped perchlet obtained from fishermen in Pabean bay, then gonads preserved by using a solution of BNF (Buffer Neutral Formalin). The gonadal histology of oosit made by HE staining method, then observed in microscope ca-mera. The development of the oocytes was classified into four stages i.e initial growth stage (the chromatin of the nucleus and perinuclear), cortical alveoli, vitellogenesis, and ripe. Based on the stages of oocytes, scalloped perchlet categorized as partial spawner. AbstrakIkan seriding (Ambassis nalua) merupakan salah satu jenis ikan di perairan Teluk Pabean, Indramayu yang berukuran kecil, transparan dan tersedia dalam jumlah melimpah. Penelitian ini bertujuan untuk melihat perkembangan sel telur secara histologis dan menentukan tipe pemijahan ikan seriding. Ikan seriding didapatkan dari hasil tangkapan nelayan di Teluk Pabean, kemudian gonad contoh diawetkan dengan menggunakan larutan BNF (Buffer Neutral Formalin). Preparat histo-logis sel telur dibuat dengan metode pewarnaan HE, kemudian diamati dibawah mikroskop berkamera. Tahapan perkembangan oosit pada ikan seriding yaitu kromatin nukleus dan perinuklear (tahap pertumbuhan awal), kortikal alveoli, vitelo-genesis, dan pematangan. Tahapan tersebut menunjukkan bahwa ikan seriding merupakan tipe ikan yang memijah secara bertahap.