Judul: Correlation between Use of Social Media, Sleep Quality,  Eating Habits, and Physical Activity with Nutritional Status of Common First  Year Program Students in IPB University
Abstrak: Penelitian ini bertujuan mengidentifikasi dan menganalisis hubungan media sosial, kualitas tidur, kebiasaan makan, dan aktivitas fisik dengan status gizi mahasiswa PPKU IPB. Studi cross sectional dilakukan pada mahasiswa PPKU IPB tahun ajaran 2019/2020. Jumlah subjek penelitian sebanyak 101 mahasiswa. Penelitian dilakukan pada bulan Oktober- November 2019 di Asrama PPKU IPB. Hasil penelitian menunjukkan bahwa subjek memiliki kebiasaan makan 3 kali sehari (63,4%), biasa sarapan pagi (85,1%), tingkat penggunaan internet tergolong tinggi (53,5%), aktivitas fisik subjek tergolong ringan (74,3%), dan kualitas tidur subjek tergolong buruk (78,2%). Hasil uji korelasi Spearman menunjukkan bahwa tidak terdapat hubungan signifikan antara aktivitas fisik, penggunaan media sosial, kualitas tidur dengan status gizi pada subjek (p<0,05). Hasil uji koreasi Spearman menunjukkan bahwa terdapat hubungan signifikan antara pendapatan keluarga (p=0,002) serta kebiasaan sarapan (p=0,005) dengan status gizi subjek., The aims of this research was to analyze correlation between social media, sleep quality, eating habits, and physical activity with nutritional status of Common First Year Program students (PPKU) in IPB University. This study used cross sectional design with student from PPKU for the 2019/2020 as the subjects. The number of study subjects is 101 students. The study was conducted in October November 2019 at the IPB Dormitory. The results showed that the subjects had the habit of eating 3 times per day (63.4%), usually doing breakfast (85.1%), the subject's internet use is classified as high (53.5%) the subject's physical activity was light (74.3%), and the subject's sleep quality was relatively poor (78.2%). The results of the correlation test showed that there was no significant relationship between physical activity, social media use, sleep quality and nutritional status in the subjects (p<0.05). However, the correlation between family income and breakfast habit with subject’s nutritional status shows a significant correlation with p-value 0.002 and 0.005 riepectively.
Keyword: Eating habits, nutritional status, sleep quality, social media

Judul: Correlation Between Stress Level, Sleep Quality, and Food Habits with Nutritional Status in IPB University Dormitory Students
Abstrak: Penelitian ini bertujuan mengetahui dan menganalisis hubungan tingkat stres, kualitas tidur, dan kebiasaan makan dengan status gizi pada mahasiswa asrama IPB. Desain penelitian ini merupakan studi cross sectional dengan jumlah subjek sebanyak 78 mahasiswa asrama IPB University. Penelitian dilakukan secara langsung pada bulan Mei 2024 melalui pengisian kuesioner dan wawancara. Instrumen pengukuran tingkat stres menggunakan kuesioner PSS-10, kualitas tidur menggunakan kuesioner Pittsburgh Sleep Quality Index (PSQI), kebiasaan makan menggunakan kuesioner Adolescent Food Habits Checklist (AFHC), status gizi diukur secara langsung pada berat badan dan tinggi badan. Sebagian besar subjek mengalami stres sedang (72%), kualitas tidur yang buruk (85%), dan kebiasaan makan yang tidak sehat (65%). Sebagian besar status gizi subjek tergolong normal (61%). Hasil analisis menunjukkan tidak terdapat hubungan signifikan antara tingkat stres, kualitas tidur, dan kebiasaan makan dengan status gizi (p>0,05)., This research aims to determine and analyze the correlation between stress level, sleep quality, and food habits with nutritional status in IPB University dormitory students. The design of this research was a cross-sectional study with 78 IPB University dormitory students as subjects. The research was conducted online in May 2024 by filling out questionnaires and interviews. Instruments for measuring stress levels using the PSS-10, sleep quality using the Pittsburgh Sleep Quality Index (PSQI) questionnaire, food habits using the Adolescent Food Habits Checklist (AFHC) questionnaire, nutritional status was measured directly on body weight and height. Most subjects experienced moderate stress (72%), poor sleep quality (85%), and unhealthy food habits (65%). Most of the subjects nutritional status was classified as normal (61%). The results of the analysis showed that there was no significant correlation between stress level, sleep quality, and food habits with nutritional status (p>0.05).
Keyword: nutritional status, sleep quality, food habits, stress level

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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