Judul: Relationship between Diet Quality and Physical Activity with Nutritional Status of Adolescents during The Covid-19 Pandemic
Abstrak: Pandemi Covid-19 menyebabkan adanya pembatasan aktivitas yang dapat memengaruhi kualitas makan dan aktivitas fisik remaja. Tujuan dari penelitian ini adalah untuk menganalisis hubungan kualitas diet dan aktivitas fisik dengan status gizi remaja selama masa pandemi. Desain penelitian adalah cross sectional dengan jumlah subjek sebanyak 100 siswa di SMA Negeri 5 Bogor. Pengumpulan data dilakukan secara semi daring. Data kualitas diet dihitung dari konversi food recall 2x24 jam menggunakan indeks Diet Quality Indeks for Adolescents (DQI-A) yang dimodifikasi menggunakan Pedoman Gizi Seimbang 2014. Data aktivitas fisik didapatkan dengan wawancara subjek menggunakan International Physical Activity Questionnare Short Form (IPAQ-SF). Status gizi ditentukan menggunakan indikator z-score IMT/U. Sebagian besar subjek (60%) merupakan perempuan dengan rata-rata usia 16,8±0,6 tahun. Status gizi subjek berdasarkan IMT/U secara keseluruhan tergolong normal dengan persentase 78%. Rata-rata skor DQI-A subjek yaitu 52,6%±12,1% yang tergolong cukup baik. Aktivitas fisik subjek tergolong rendah ke sedang. Tidak terdapat hubungan yang signifikan antara kualitas diet dengan IMT/U (p>0,05). Namun, status gizi IMT/U memiliki hubungan signifikan dengan skor METs (p<0,05)., The Covid-19 pandemic has led to restrictions on activities that can affect the quality of food and physical activity in adolescents. The purpose of this study was to analyze the relationship between diet quality and physical activity with the nutritional status of adolescents during the pandemic. The research design was cross-sectional with the number of subjects as many as 100 students at SMA Negeri 5 Bogor. Data collection is done semi-online. Diet quality data was calculated from the 2x24 hour food recall conversion using the Diet Quality Index for Adolescents (DQI-A) modified using Balanced Nutrition Guidelines 2014. Physical activity data was obtained by interviewing subjects using the International Physical Activity Questionnare Short Form (IPAQ-SF). Nutritional status was determined using the BMI for age z-score indicator. Most of the subjects (60%) were female with an average age of 16.8±0.6 years old. Overall nutritional status based on BMI for age is normal with a percentage of 78%. The average DQI-A score of the subjects was 52.6%±12.1% which classified quite good. Physical activity is classified as low to moderate. There was no significant relationship between diet quality and BMI for age (p>0.05). However, BMI for age had a significant relationship with METs scores (p<0.05)
Keyword: Adolescents, diet quality, DQI-A, nutritional status, physical activity

Judul: Nutrients Intake and Lifestyle With Adolescent Nutritional Status During The Covid-19 Pandemic
Abstrak: Masa pandemi Covid-19 menimbulkan pembatasan aktivitas di luar rumah termasuk belajar secara daring yang mempengaruhi asupan zat gizi dan gaya hidup (screen time, durasi tidur, aktivitas fisik) terutama kelompok usia remaja. penelitian ini bertujuan menganalisis hubungan antara asupan zat gizi dan gaya hidup (screen time, durasi tidur, aktivitas fisik) dengan status gizi remaja. Desain penelitian cross sectional study dengan subjek sebanyak 99 orang yang dilakukan pada Desember 2020 hingga Januari 2021 di MTsN 5 Kuningan. Subjek dipilih secara purposive dengan pengumpulan data primer melalui kuesioner dan wawancara. Subjek berusia 13-15 tahun dengan sebagian besar (83,84%) memiliki status gizi baik. Selama pandemi Covid-19 subjek mengalami penurunan durasi tidur (44,4%) dan kebiasaan olahraga (53,6%), serta peningkatan screen time (57,6%) dan konsumsi camilan (44,4%). Durasi tidur tidak memiliki hubungan signifikan dengan screen time, aktivitas fisik, dan asupan zat gizi. Screen time juga tidak memiliki hubungan dengan aktivitas fisik dan asupan zat gizi. Sementara itu, status gizi memiliki hubungan negatif signifikan dengan kecukupan energi, protein, dan karbohidrat, namun kecukupan lemak dengan status gizi tidak memiliki hubungan signifikan. Status gizi subjek juga tidak memiliki hubungan dengan screen time, durasi tidur, dan aktivitas fisik., The Covid-19 pandemic period has caused restrictions on activities outside the home, including online learning which affects nutrient intake and lifestyle (screen time, sleep duration, physical activity), especially adolescent age group. This research aimed to analyze the correlation between nutrient intake and lifestyle (screen time, sleep duration, physical activity) with adolescent nutritional status. The research design used cross sectional study with total of 99 subjects, which was conducted from December 2020 to January 2021 at MTsN 5 Kuningan. Subjects were selected purposively by collecting primary data through questionnaires and interviews. Subjects aged 13-15 years with most (83,84%) had good nutritional status. During the Covid-19 pandemic, subjects experienced a decrease in sleep duration (44,4%) and exercise habits (53,6%), as well as an increase in screen time (57,6%) and snack consumption (44,4%). Sleep duration didn’t have a significant correlation with screen time, physical activity, and nutrient intake. Screen time also has no correlation with physical activity and nutrient intake. Meanwhile, nutritional status had a significant negative correlation with energy, protein, and carbohydrate adequacy, but fat adequacy with nutritional status didn’t have a significant correlation. The nutritional status of the subjects also had no correlation with screen time, sleep duration, and physical activity.
Keyword: nutrients adequacy level, nutritional status, physical activity, screen  time, sleep duration

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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