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Microalgae is a promising and innovative biological resource. Indonesia has the potential for the development of microalgae production. One of the microalgae that have high economic value is Arthrospira platensis. In the production of microalgae, the development of suitable media and environmental conditions need to be factors that must be considered. This study aimed to analyze the effect of different nitrogen sources and nitrogen doses and their interaction on the growth of microalgae Arthrospira platensis cultured in fresh water. In addition, analyzing the water quality of Arthrospira platensis culture media. This study used an experimental method of Completely Randomized Factorial Design) with two factors. The first factor is the nitrogen source (Sodium nitrate, Potassium nitrate, and Calcium nitrate). The second factor is the dose of nitrogen source (2 g/l.2.5 g/l.3 g/l). The main parameter observed was microalgae growth, while the supporting parameter was the water quality which affected the growth of Arthrospira platensis. The highest density results were found in the provision of a nitrogen source of Ca(NO3)2 3 g/l, which was 370,000 cells/ml. The results of the ANOVA test showed that the type of nitrogen source, the dose, and the interaction between the two affected the specific growth rate of Arthrospira platensis. The environmental conditions during culture ranged from 20.2°C-26.2°C, pH values ​​8.95 – 10.18, and dissolved oxygen 9.17 – 9.77 mg/L.

Edwardsiella tarda is a type of gram-negative intracellular pathogen that can cause mass demise in fish farming. The development of edwarsiellosis due to E.tarda infection causes significant economic losses for cultivators. Aloe vera is a perennial succulent plant like a cactus, drought withstand, and belongs to the Liliaceae family, of which there are more than 360 known species (Wijaya and Masfufatun, 2022). Aloe vera is one of the plants known to contain active ingredients that can inhibit the growth of bacteria. The results of phytochemical analysis of a crude extract of Aloe vera showed the presence of active compounds, specifically flavonoids, tannins, triterpenoids, and saponins. MIC analysis showed that the lowest absorbance value of Aloe vera was obtained at a concentration of 50 mg/L with a value of 0.316, indicating a decrease at each concentration. The concentration of 50 mg/L is close to the positive control which indicates that at a concentration of 50 mg/L, it can be the reference for the lowest concentration in determining the dose of Aloe vera extract which is known that the presence of antibacterial compounds in Aloe vera extract can inhibit the growth of E.tarda bacteria. The inhibition zone test was carried out with graded concentrations of 50 mg/L, 100 mg/L, 150 mg/L, 200 mg/L and 250 mg/L with an observation time of 24 hours post-incubation and 48 hours post-incubation. Inhibition zone analysis with the highest diameter was at 200 mg/L. SEM analysis by distributing a crude extract of Aloe vera affected E.tarda bacteria specifically, lysis occurring in bacterial cells

Microplastics are contaminants resulting from plastic fragmentation with a size

Scientific literacy is the main key in facing the challenges of the 21st century. The reason for the low ability of students in scientific literacy is the lack of scientific literacy content in teaching materials. The importance of students' knowledge of scientific literacy skill information is to provide solutions to problems in the field of literacy. This study aimed to determine the scientific literacy abilities of Class VII students of the Umar Mas'ud Sangkapura School. A combination descriptive research method was used in this study. Under the direction of the Umar Mas'ud School, a cluster random sampling method was used to select the research sample, which included 40 seventh graders from MTS Umar Mas'ud and SMP Umar Mas'ud. The instrument was carried out by testing scientific literacy questions and interview guideline sheets. The results of the scientific literacy tests and interviews were carried out using data analysis techniques by giving a score to each student's answer. The data obtained were interpreted into two categories, scientific literacy scores, and interview results. The average grade VII grade IPA students of the Umar Mas'ud Sangkapura Foundation are 32,563, placing them in the low category. There are several factors that cause students' low scientific literacy skills, including a lack of interest in reading, instructional media that do not prioritize scientific literacy, and a lack of direction from the teacher

Arthrospira platensis culture requires macro and micronutrients. The nutrients needed by Arthrospira platensis according to Agustina and Herman (2021) are macronutrients consisting of nitrogen (N), phosphorus (P), potassium (K), sulfur (S), iron (Fe), magnesium (Mg), silicon (Si), and calcium (Ca). Micronutrients consist of zinc (Zn), cobalt (Co), molybdenum (Mo), boron (B), and copper (Cu). Rice-washing wastewater contains macro and micronutrients needed for the growth of Arthrospira platensis. Almost all of the nutrients needed by Arthrospira platensis are found in the wastewater, except for Co. Previous studies have shown that rice-washing wastewater can be used for Arthrospira platensis culture, but the growth rate is still higher than Walne fertilizer 0.5 ml/L. Zarrouk fertilizer as a standard growth medium for Arthrospira platensis shows that this fertilizer has better growth results than Urea and NPK fertilizers. This research was conducted to determine the effect of rice-washing wastewater as a nutrient source for culture media or a combination of Zarrouk fertilizer and rice-washing wastewater so that it can be used to increase the biomass and carotenoid pigments of Arthrospira platensis. This research used a Factorial Completely Randomized Design (CRD) with 12 treatments and 3 replications. Arthrospira platensis quality test was carried out by testing dry biomass and carotenoid content. The ANOVA test results showed that this study's treatment had a significant effect on the carotenoid content and biomass of Arthrospira platensis. The treatment with the highest effect of biomass and carotenoids was obtained in the treatment of 1.5 ml/L of rice-washing wastewater

Vannamei shrimp (Litopenaeus vannamei) is one of the leading commodities in Indonesian aquaculture. The cultivation potential that is developing at this time is with intensive technology. However, along with the development of intensive technology, it experienced problems, namely crop failure caused by a decrease in water quality. This study aims to examine the physical and chemical dynamics of vannamei shrimp pond water cultivated with a semi-biofloc system. This study used a survey method and was statistically analyzed using Ms. Excel and Principal component analysis (PCA). Physical and chemical parameters of water that are measured and observed include Temperature, Brightness, pH, Dissolved Oxygen, Salinity, Carbon Dioxide (CO2), Total Organic Matter, Nitrate (NO3), Phosphate (PO4-) and Ammonia (NH3). The results showed that all the physical and chemical parameters of pond water experienced daily and weekly fluctuations during shrimp rearing. Average temperature fluctuations during the study ranged from 26.7 – 32.5 oC, brightness ranged from 26.5 – 85.0 cm, pH ranged from 7 – 8 tended to be normal, dissolved oxygen ranged from 5.8 – 8.8 mg/L, salinity ranged from 18.3 – 22.8, carbon dioxide (CO2) average values during rearing were 0 mg/L, TOM ranged from 18.42 – 71.80 mg/l, nitrate 0.022 – 0.136 mg/l, phosphate 0.017 – 0.136 mg/L and ammonia ranging from 0.008 – 0.088 mg/l. While, the results of the PCA analysis show that dissolved oxygen and brightness significantly affect the life of the shrimp that are cultivated. So it can be concluded that the dynamics of the physics-chemistry of water measured during the study showed that dissolved oxygen and brightness fluctuated and affected aquaculture activities.

Research has been carried out on Measuring and Determining the Output Factors of 6 and 10 MV WFF photon beams in Small Square and Rectangular fields using Semiflex TM 31010 and PintPoint TM 31014 Ionization Chamber. This study aims to determine the value of the small field output factor. Measurements were carried out in a water phantom at a depth of 10 cm with a 100 cm SSD technique. The area of ​​the irradiation field used is (2 × 2; 3 × 3; 4 × 4; 2.5 × 1.6; 3.6 × 2.5; 4.5 × 2; and 5 × 3.2) cm2. Field output factor calculations were performed using the IAEA TRS. 483 dosimetry protocol. The results of measurements and calculations obtained for the two detectors used show that a decrease in the value of the output factor occurs when the field size is getting smaller. The output factor value in a small rectangular field looks smaller when compared to the output factor value in a small square field.

Landslides are one of the factors caused by subsurface structures that are not compact, and have low density or resistivity values due to changes in groundwater. Rainwater that infiltrates into the ground will reach to an impermeable layer which is identified as a slip plane. This research was conducted in the Kastoba Lake area, Bawean Island, Indonesia. The purpose of this study is to determine the slip plane and the direction of the landslide in the studied area. Data acquisition was carried out based on a preliminary study of residual anomaly contour analysis from gravity data, then geoelectric data acquisition was carried out in the studied area. The results of lithological analysis on 3D geoelectric resistivity modeling in this study obtained three layers of subsurface structures, namely topsoil, clay, and lavas. The slip plane of the study area is above the clay layer (7.25 meters depth). The results of the 3D interpretation indicated that the direction of the landslide was towards the north, as evidenced by the existence of public information that the area studied had landslides with the avalanche direction towards the north. For further analysis, a factor of safety analysis is needed based on the analysis of the bore hole drilling method in the studied area

Kastoba Lake in Bawean Island Indonesia is a tourist attraction that has a level of vulnerability in landslide disasters. The landslides has been happen. From the large and small scale in the Kastoba Lake. Base on the problem, the landslides occured due to the field of derailment. According to the above statement, it was necessary to know the subsurface structure and the field of avalanche derailment in the kastoba lake area. This data was allowed by geophysical resistivity method which a dipole-dipole configuration with 4 measurement points. The acquisition of data was based on preliminary studies from the analysis of landslide vulnerability level maps (DEM Alos data processing) that have been done first. The results of lithological analysis with geoelectric resistivity methods in this research obtained three layers of subsurface structure, namely top soil (top layer) with a resistivity value of 7-110 Ωm, clay (middle layer) which was a resistivity value of 110-210 Ωm and lava (bottommost layer) which was a resistivity value of 210-357 Ωm. The field of gelincir in the research area was on the top layer of soil composed of weathering of rocks mixed with organic material or leaf/tree decay with an average depth of 7.25 meters. Thus, this research can be one of the parameters of landslide disaster mitigation in the development of geotourism in Kastoba Lake