The experience of using Arthrospira platensis as a feed additive in the cultivation of juveniles of the Far Eastern sea cucumber (Apostichopus japonicus)

The experience of using the culture of Arthrospira (Spirulina) platensis as an additive to feed when growing juveniles of the Far Eastern sea cucumber in aquarium conditions is described. The experimental food ration included live culture of spirulina, macroalgae, protein and stimulant supplements. There were no significant differences in the survival rates of individuals (experiment – 69.5%, control – 65.7%). The greatest increase in the mass of individuals was observed in the experimental container - by an average of 0.047 g. In the control group - an average of 0.009 g.

Uncovering Transcriptional Responses to Fractional Gravity in Arabidopsis Roots

Although many reports characterize the transcriptional response of Arabidopsis seedlings to microgravity, few investigate the effect of partial or fractional gravity on gene expression. Understanding plant responses to fractional gravity is relevant for plant growth on lunar and Martian surfaces. The plant signaling flight experiment utilized the European Modular Cultivation System (EMCS) onboard the International Space Station (ISS). The EMCS consisted of two rotors within a controlled chamber allowing for two experimental conditions, microgravity (stationary rotor) and simulated gravity in space. Seedlings were grown for 5 days under continuous light in seed cassettes. The arrangement of the seed cassettes within each experimental container results in a gradient of fractional g (in the spinning rotor). To investigate whether gene expression patterns are sensitive to fractional g, we carried out transcriptional profiling of root samples exposed to microgravity or partial g (ranging from 0.53 to 0.88 g). Data were analyzed using DESeq2 with fractional g as a continuous variable in the design model in order to query gene expression across the gravity continuum. We identified a subset of genes whose expression correlates with changes in fractional g. Interestingly, the most responsive genes include those encoding transcription factors, defense, and cell wall-related proteins and heat shock proteins.

UJI TANAMAN TALAS (Colocasia esculenta) SEBAGAI AGEN FITOREMEDIASI AIR SUNGAI CIKAPUNDUNG

Pencemaran sungai akibat akumulasi limbah domestik dan industri merupakan tantangan yang serius bagi kelestarian hidup biota perairan. Limbah domestik/rumah tangga yang sering dibuang ke perairan dapat mengganggu ekosistem yang ada di perairan tersebut. Sejauh ini berbagai upaya sudah mulai dilakukan industri dengan pembuatan instalasi limbah terpadu, namun upaya tersebut masih belum maksimal karena rendahnya kesadaran masyarakat dan lemahnya pengawasan dari instansi terkait. Salah satu upaya untuk mengurangi limbah domestik adalah dengan membuat biology irigation dengan memanfaatkan tanaman talas Colocasiaesculenta. Studi pemanfaatan tanaman air untuk pengolahan air limbah domestik dalam sistem biology irigation ini dilakukanuntuk mengetahui efisiensi penyerapan unsur hara oleh C. esculenta. Metode penelitian yang diterapkan adalah menumbuhkan C. esculenta dalam suatu wadah percobaan race ways yang dialiri air limbah domestic dengan sistem subsurface flow (SSF). Hasilpenelitian menunjukkanbahwa secara fisik C.Esculenta dapat tumbuh lebih baik pada substrat yang mengandung air sungai Cikapundung dibandingkan dengan C.Esculenta yang ditumbuhkan pada substrat yang ditambahkan air sumur. Hal tersebut ditunjukkan oleh perbedaan pertumbuhan panjang dan berat tanaman tersebut. Hasil analisis parameter karbon organik (C-organik), nitrogen (N-kejdahl) dan fosfat (P) pada jaringan tanaman talas (bagian daun dan akar) menunjukkan adanya peningkatan konsentrasi bahan organic dalam jaringan tanaman tersebut yang berbanding lurus dengan pertumbuhan tanaman talas (tinggi dan berat tanaman talas), sebagaimana ditunjukkan oleh konsentrasi penyerapan C sebesar 2000 mg dan N 100 mg selama 63 hari. Kata kunci : Colocasia esculenta, limbah domestik, fitoremediasi. AbstractPollution of rivers due to the accumulation of domestic and industrial wasteis aserious challenge to the survival ofaquatic biota. Domestic waste/ household is often thrown into the water can interfere waters ecosystems. So far, many efforts have been done such as installation integrated waste treatment, but these efforts are not yet fulfill the requirement due to low awareness and lack of oversight agencies. One of the efforts to reduce domestic wasteis by making use of plant biology irrigation with Colocasia esculenta. Study ofutilization of aquatic plants for domestic wastewater treatment systems biology irrigation was conducted to determine the efficiency of nutrient uptake by C.esculenta. The research method was applied by growing C.esculenta in an experimental container -carrying raceways domestic wastewater system with subsurface flow (SSF). The results showed that physical C.Esculenta may grow well on substrates containing water Cikapundung river compared to C.Esculentagrown ona substrateis added waterwells. This is shown by the differences in growth and weight of the plants. The results of the Laboratory analysis of organic carbon (C-organic), nitrogen (N-kejdahl) and phosphate (P) on the taro plant (the leaves and roots) showed an increase nutrient in plant tissues which is directly proportional to the growth of taro plants (taro plant height and weight), as shown by a concentration of 2000 mg C sequestration and N100 mg for 63 days. Keywords: Colocasia esculenta, domestic waste, phytoremediation.

Stability of multiple steady states of convection in laterally heated cavities

A parametric study of multiple steady states, their stability, onset of oscillatory instability, and some supercritical unsteady regimes of convective flow of a Boussinesq fluid in laterally heated rectangular cavities is presented. Cavities with four no-slip boundaries, isothermal vertical and perfectly insulated horizontal boundaries are considered. Four distinct branches of steady-state flows are found for this configuration. A complete study of stability of each branch is performed for the aspect ratio A (length/height) of the cavity varying continuously from 1 to 11 and for two fixed values of the Prandtl number: Pr = 0 and Pr = 0.015. The results are represented as stability diagrams showing the critical parameters (critical Grashof number and the frequency at the onset of the oscillatory instability) corresponding to transitions from steady to oscillatory states, appearance of multi-roll states, merging of multiple states and backwards transitions from multi-roll to single-roll states. For better comparison with the existing experimental data, an additional stability study for varying Prandtl number (0.015 [les ] Pr [les ] 0.03) and fixed value of the aspect ratio A = 4 was carried out. It was shown that the dependence of the critical Grashof number on the aspect ratio and the Prandtl number is very complicated and a very detailed parametric study is required to reproduce it correctly. Comparison with the available experimental data for A = 4 shows that the results of a two-dimensional stability analysis are in good agreement with the experimental results if the width ratio (width/height) of the experimental container is sufficiently large. The study is carried out numerically with the use of two independent numerical approaches based on the global Galerkin and finite-volume methods.

CROWDING AND ACTIVITY

When the relative velocity of flies is estimated from the frequency of contact of flies with a given area, the resulting picture of activity is misleading because of time-wasting activities arising from encounters between flies. Prediction of this encounter rate is greatly facilitated by the use of Lloyds (1967) index of crowding, which allows for the effects of the non-random distribution of the flies. Prediction of the number of contacts of flies with an inscribed area within the experimental container, was highly successful when the effects of the non-random locomotion of the flies was included in the model of activity.