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: Relationship between Diet Quality, Sleep Quality, and  Physical Activity with the Nutritional Status of IPB Students.
Abstrak: Permasalahan gizi saat ini pada kelompok dewasa awal adalah permasalahan gizi ganda, yang disebabkan berbagai faktor, diantaranya kualitas diet, kualitas tidur, dan aktivitas fisik. Penelitian ini bertujuan menganalisis hubungan kualitas diet, kualitas tidur, dan aktivitas fisik terhadap status gizi mahasiswa tingkat akhir IPB. Desain penelitian adalah cross sectional study, dilaksanakan Desember 2022 sampai Januari 2023 pada 40 mahasiswa. Pengumpulan data dilakukan dengan wawancara, pengukuran antropometri, dan pengisian kuesioner. Hasil penelitian menunjukkan sebagian besar subjek (68%) memiliki pengetahuan gizi cukup. Hampir seluruh subjek (95%) memiliki kualitas diet rendah berdasarkan Diet Quality Index International (DQI-I). Lebih dari 3/4 subjek (77,5%) memiliki kualitas tidur buruk berdasarkan Pittsburgh Sleep Quallity Indeks (PSQI). Hampir separuh subjek (42,5%) memiliki aktivitas fisik sedang berdasarkan International Physical Activity Questionnaire (IPAQ-SF). Status gizi hampir 2/3 subjek normal (65%). Hasil Uji korelasi Spearman menunjukkan tidak ada hubungan signifikan (p>0.05) antara pengetahuan gizi dengan kualitas diet, kualitas diet dengan status gizi, kualitas tidur dengan status gizi, dan aktivitas fisik dengan status gizi. Terdapat kecenderungan skor pengetahuan gizi baik pada subjek dengan kualitas diet tinggi, kecenderungan skor kualitas diet rendah dan skor kualitas tidur buruk pada subjek dengan status gizi tidak normal. Kata kunci: aktivitas fisik, kualitas diet, kualitas tidur, pengetahuan gizi, status gizi, Current nutritional problem in early adulthood is double burden malnutrition, caused by various factors, including diet quality, sleep quality and physical activity. This study aims to analyze relationship between diet quality, sleep quality and physical activity on the nutritional status IPB final year students. Research design was cross-sectional study, carried out from December 2022 to January 2023 on 40 students. Data collection was carried out by interviews, anthropometric measurements, and filling out questionnaires. Results showed majority subjects (68%) had sufficient nutritional knowledge. Almost all subjects (95%) had low diet quality based on Diet Quality Index International (DQI-I). More than 3/4 subjects (77.5%) had poor sleep quality based on Pittsburgh Sleep Quality Index (PSQI). Almost half of subjects (42.5%) had moderate physical activity based on International Physical Activity Questionnaire (IPAQ-SF). Nutritional status of almost 2/3 subjects was normal (65%). Results of Spearman correlation test showed no significant relationship (p>0.05) between nutritional knowledge and diet quality, diet quality and nutritional status, sleep quality and nutritional status, physical activity and nutritional status. There was tendency for good nutritional knowledge scores in subjects with high diet quality, tendency for low diet quality scores and poor sleep quality scores in subjects with abnormal nutritional status
Keyword: diet quality, nutritional knowledge, nutritonal status, physical activity, sleep quality

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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