Jurnal Ilmiah Sains

Geographically Weighted Regression Modeling with Adaptive Gaussian Kernel Weighting on GRDP in Indonesia

Frangly Elviano Tangka — 2024-06-11

The purpose of this study is to determine the variables that affect Gross Regional Domestic Product (GRDP) in Indonesia in 2022 using Geographically Weighted Regression (GWR) with Adaptive Gaussian kernel weighting function. The data used in this study uses secondary data taken from the website of the Central Bureau of Statistics. The variables used are gross regional domestic product of 34 provinces in Indonesia (Y, in billion rupiah), labor force participation rate (X1, in %), foreign investment (X2, in million dollars), open unemployment rate (X3, in %) and human development index (X4, in %). Data were analyzed using GWR with adaptive gaussian kernel weighting function. GRDP in all provinces on the island of Sumatra (11 provinces), DKI Jakarta province, Banten province, and West Kalimantan province are influenced by foreign investment (X₂) and human development index (X₄). Meanwhile, GRDP in the other 19 provinces is only influenced by foreign investment (X₂). GWR model with adaptive gaussian kernel weighting function is formed differently for each province in Indonesia.

Keywords: Adaptive gaussian kernel; GWR; gross regional domestic product

Interpolation Methods: A Study of Solving Annual Data into Quarterly and Monthly Data

Tri Oldy Rotinsulu — 2024-09-19

This study aims to analyse the effect of Export Value (EKS_US$) and Exchange Rate (KURS_US$) on Gross Domestic Product (GDP) as a proxy for economic growth in Indonesia using multiple linear regression based on interpolated monthly data from annual data. In this paper, it is also explained about calculation examples, quarterly and monthly data interpolation methods using data from the Central Bureau of Statistics, namely Indonesia's Gross Domestic Product (GDP) for 2021-2022 at constant 2010 prices. Based on the calculation results, using multiple linear regression of monthly data for the 2018-2022 period, it shows that the estimated model has the best estimator, which is indicated by the variables used, passing the diagnostic test in the form of Multicollinearity, Heteroscedasticity, Autocorrelation, Normality, and Linearity tests. This indicates that the estimator value of the observed data is able to represent the random behaviour of the actual data. However, everything returns to the researcher, at which stage will be chosen is greatly influenced by various factors and considerations of the researcher. Thus, at certain stages and situations, it is very open to researchers to use data interpolation, especially on all data that has flow characteristics, such as GDP data, export values, exchange rates and others.

Keywords: Interpolated data; annual data; quarterly data; monthly data; diagnostic tests

Measurement and Analysis of Noise Levels from Loudspeakers on Public Transportation in Kupang, East Nusa Tenggara

Theophilus Wellem — 2024-09-26

The government is very concerned about the threshold value of human hearing that causes permanent noise-induced hearing loss (NIHL), such as noise caused by public transportation (bemo) in Kupang. This research aims to increase the awareness of the bemo user in Kupang to prevent hearing loss due to noise from bemo audio devices. Noise measurements due to public transportation are usually carried out outside the vehicle, for example, on the street, but in this study, measurements were carried out inside the vehicle (bemo). Data was obtained from (1) Data on sound intensity in public transport taken manually using a Sound Pressure Level (SPL) meter and (2) Data on the working hours of the drivers taken manually by asking how long they drive in a day. The results of of each route and the average of of eight routes showed a sound intensity above the threshold set by the government, i.e., 70 dB. Routes 1 and 3 are bemo routes that need attention because they have maximum sound intensity of more than 100 dB and are included in the Very Loud category. Meanwhile, the other routes are included in the Loud category. Furthermore, the average time a driver stays in a bemo daily is 13.5 hours, which concluded that all drivers are at risk of hearing loss. Therefore, special attention is needed from the government because this can result in driver hearing loss.

Keywords: Bemo; Kupang; Noise-induced hearing loss; Public transportation; Sound intensity

Effect of Phosphate Source on Growth of Chlorella vulgaris Cultured with Indole-3-Acetic Acid-Producing Bacteria

Lintang Guritno Cucu Wijaya — 2024-10-17

The need for energy sources in Indonesia continues to increase, in 2018 Indonesia is a country with energy consumption of around 114 Million Tons of Oil Equivalent (MTOE). Therefore, alternative energy from biomass such as biodiesel is needed. Chlorella vulgaris is a microbe suitable for alternative energy because it contains up to 80% lipids. Chlorella vulgaris needs phosphorus for cell growth from fertilizer for the production of Adenosine Triphosphate (ATP). In addition to phosphorus, co-cultures with IAA-producing bacteria can promote the growth of C. vulgaris. This study was conducted to evaluate the influence of phosphate sources on the growth of C. vulgaris cultured with IAA-producing bacteria. This study was carried out by co-culture C. vulgaris and IAA-producing bacteria with different phosphate sources on Gusrina medium for 27 days. The treatment consisted of treatment A (control), B Triple Super Phosphate (TSP), and C Super Phosphate-36 (SP-36). Cell growth was calculated using the Petroff-Hausser counting chamber method followed by the ANOVA test. The highest cell growth was obtained in treatment B (TSP), followed by treatment C (SP-36), and finally treatment A (control). The results showed that the addition of phosphate sources had an effect on the growth of C. vulgaris with the highest number of cells found in treatment B (TSP) of 2,66 × 10⁶ cells/mL.

Keywords: Chlorella vulgaris; co-culture; phosphorus

Analysis of Drought in the Sekayam Watershed during a Very Strong El Niño Event (1997)

Ajeng Candra Indrawati — 2024-10-19

Low rainfall and limited surface water availability during El Niño events leave significant portions of Indonesia highly susceptible to drought. As a mitigation strategy to address the impacts of the El Niño phenomenon, a comprehensive analysis of drought characteristics in affected regions is essential. This study aims to assess the characteristics of meteorological drought using the Standardized Precipitation Index (SPI) method, and hydrological drought through the Standardized Streamflow Index (SSI) method, within the Sekayam Watershed. The data utilized in this study includes rainfall and streamflow data from the period of the exceptionally strong El Niño event in 1997.The findings indicate that meteorological drought in the Sekayam Watershed was predominantly classified as moderately dry, with the most severe drought conditions observed in January, March, and December, affecting a small portion of the upstream area of the watershed. In contrast, hydrological drought was primarily categorized as dry, with the most severe conditions occurring in July. Moreover, the correlation between SPI and SSI during the 1997 El Niño event was found to be strong, with a correlation coefficient of 0.77.

Keywords: Rainfall; drought; el niño; standardized precipitation index

Differences in Anti-inflammatory Effects of Celecoxib Emulgel Preparations with Variations in Surfactant Concentration between Lecithin and Tween 80

Achmad Quraisy Aljufri — 2024-10-31

Celecoxib is a non-steroidal anti-inflammatory drug (NSAID) which is widely used to treat inflammation such as rheumatoid arthritis and primary dysmenorrhea. The absorption of celecoxib in the body is very low when taken orally, so it can be increased by changing the route of administration via transdermal route such as emulgel. This study aims to determine the increase in the anti-inflammatory activity of celecoxib emulgel with varying concentrations of surfactants in formula with Lecithin and formula with Tween 80. Celecoxib emulgel, was made into 3 formulas with variations in the concentration for each formula with Lecithin (FI=3%; FII=5%; FIII=7%) and Tween 80 (FI=5%; FII=10%; FIII=15%). The anti-inflammatory activity test was carried out by inducing edema in the soles of rats' feet using carrageenan. Rats were divided into 5 groups for each formula: 1) negative control, 2) without surfactant, 3) FI, 4) FII, and 5) FIII. The edema volume was measured every 1 hour for 6 hours using a plethysmometer. Results of the anti-inflammatory test showed that the average value of AUC_0-360 in the Lecithin group = 57.97-77.17 μg/hour/mL and in the Tween 80 group = 51.45-77.17 μg/hour/mL. %DAI results of formula without surfactant=9.33%, FI (Lecithin=10.01%; Tween 80=24.49%), FII (Lecithin=18.36%; Tween 80=29.05%), and FIII (Lecithin=24.88%; Tween 80=33.33%). Based on these data, it can be concluded that there is an increase in the anti-inflammatory effect of celecoxib emulgel with increasing surfactant concentration in the formula with Lecithin and in the formula with Tween 80.

Keywords: Anti-inflammatory; celecoxib; emulgel; surfactant

Effect Pineapple Extract (Ananas comosus L, Merr) To Dadih Quality During Cold Temperature Storage

Benika Naibaho — 2024-11-03

The objectives of this research were to study the effect of storage temperature and pineapple extract on physicochemical, organoleptic, and total bacterial colony of curd. This study used factorial completely randomized design with 2 factors, with two replications. The results showed that storage temperature, pineapple extract and interaction affected significantly fat and protein content, total bacterial colonies, and organoleptis. Storage temperature significantly affected pH, while pineapple extract did not affect pH. The highest fat content wat at room temperature storage without the addition of pineapple extract, namely 12.91%, the highest protein content was at room temperature storage with the addition of 10% pineapple extract, namely 4.74%. Storage at cold temperatures with the addition of 2.5% pineapple extract produced the highest total colonies, namely 2.6 x 10⁶ CFU. At room temperature storage, panelists tended to dislike the color, aroma, and texture of the curd. However, at refrigerator temperature storage, panelists preferred the color of the curd and really liked the taste. Panelists tended to like the curd both without pineapple extract and with pineapple extract. The addition of 7.5% pineapple extract and storage at cold temperatures resulted in a protein content of 4.78% and a fat content of 10.67% which met the National Yoghurt Quality Standard.

Keywords: Lactic Acid Bacteria; Curd; Pineapple; Total Bacterial Colonies

Physical Characteristics, Moisture Content and Organoleptic Properties of Afkir Laying Hen Meat with Different Marination Durations in Pineapple Crown Extract

Siti Susanti — 2024-11-03

Afkir laying hen meat has a tough texture, making it less desirable to consumers. Pineapple crown extract is known to improve the texture of spent laying hen meat due to its bromelain enzyme content. This study aims to determine the effect of marination duration using pineapple crown extract on the pH, cooking loss, water content, water holding capacity, texture, and organoleptic value of spent laying hen meat. The study was conducted using a Completely Randomized Design with 4 treatments (different marination times of 0, 2, 4, and 6 hours) and 5 replications. The parameters observed in this study included pH, cooking loss, water content, water holding capacity, texture, and organoleptic values. Test data were analyzed statistically using Analysis of Variance with a 5% significance level, and if significant effects were found, the analysis was followed by Duncan’s Multiple Range Test. Organoleptic test data were analyzed with the Kruskal-Wallis method, and if there were significant effects, further analysis was conducted using the Mann-Whitney test. The results showed a significant effect (P<0.05) of marination time using pineapple crown extract on the pH, water content, and organoleptic parameters, including taste, texture, color, and overall preference, with no significant effect (P>0.05) on cooking loss, water holding capacity, or the aroma attribute in the organoleptic test. Marination time also decreased the toughness of afkir laying hen meat texture, as analyzed descriptively. Marination for 2-6 hours decreased pH and water content, tenderized the texture, and improved meat preference.

Keywords: Afkir laying hen; bromelain; tenderness; pineapple crown; marination

Detection of Aquifer Infiltration Zones Using Resistivity and Induced Polarization Methods

As'ari As'ari — 2024-11-18

Infiltration zones that are water providers for aquifers are often neglected, resulting in the sustainable use of groundwater resources will be disrupted. The research is intended to determine rainwater catchment areas as water suppliers for aquifers on the coast of East Tondano Beach. The location of the research is in the coastal area of East Tondano, Minahasa Regency. Exploration of subsurface rock layer detection using the resistivity geoelectric method and induced polarisation, dipole-dipole configuration, 10 m space. Data acquisition using multielectrode resistivity and IP meter MAE type X612-EM. The measurement line of the two methods is the same, the data was measured on 2 lines, with line 1 being 240 m long and line 2 being 360 m long. A rainwater infiltration zone with a resistivity of 48<ρ<192 Ωm was identified, on track 1 there was a infiltration zone at meters 105-135, a layer with low resistivity was identified at meters 70-150 with a resistivity of 3-48 Ωm and a depth of ≥ 15 m.. Based on the results of the IP meter, no suspected groundwater aquifer was found, so rainwater is estimated to flow directly into the sea. On line 2, the infiltration zone was detected at meters 80-105 and meters 275-315. The layer with a low resistivity value at 100-275 meters with a resistivity of 3-48 Ωm, has a depth of ≥ 20 m. The results of the IP measurement, layer with low chargeability ≤ 0.8 ms are found on the 180-200th meter. Suspected groundwater aquifer at 180-200 meters with a depth of 45-65 m.

Keywords: Aquifer; resistivity; infiltration zones