Judul: Factors Related with Vegetables and Fruits Consumption among IPB University Students During the Distance  Learning Period
Abstrak: Pandemi covid-19 menyebabkan diterapkannya sistem Pembelajaran Jarak Jauh (PJJ) pada mahasiswa IPB yang juga mengubah pola konsumsi makanannya termasuk sayur dan buah. Tujuan penelitian ini ialah mengetahui faktor-faktor yang berhubungan dengan konsumsi sayur dan buah pada mahasiswa IPB selama PJJ. Penelitian ini dilakukan pada November 2020 menggunakan desain studi cross sectional dengan metode pengambilan sampel non-probability accidental sampling yang melibatkan 66 subjek dari mahasiswa semester 3 IPB. Faktor-faktor yang menjadi fokus penelitian ini ialah karakteristik subjek, karakteristik sosial ekonomi keluarga subjek, ketersediaan sayur dan buah di rumah, suku subjek, wilayah tempat tinggal, preferensi sayur dan buah, serta waktu mengenal sayur dan buah. Terdapat hubungan signifikan negatif konsumsi sayur dengan pendidikan ayah (p=0,020, r=-0,287) serta hubungan signifikan positif konsumsi buah dengan preferensi buah (p=0,000, r=0,000). Terdapat perbedaan signifikan konsumsi sayur antara subjek yang tinggal di kota dengan subjek yang tinggal di desa (p=0,039)., The COVID-19 pandemic led to the implementation of the Distance Learning (PJJ) system for IPB students who also changed their food consumption patterns, including vegetables and fruit. The purpose of this study to know the related factors with the vegetables and fruit consumption among IPB University students during PJJ. This research was conducted in November 2020 using a cross sectional study design with a non-probability accidental sampling method involving 66 subjects from 3rd semester students. The factors that become a focus of this research are the subject characteristics, socio-economic of subject's family, the availability of vegetables and fruit at home, the subject's ethnicity, the residential area, preferences of vegetables and fruits, and the time to know vegetables and fruits. There is a significant negative relationship of vegetable consumption with father's education (p=0.020, r=-0.287) and a significant positive relationship of fruit consumption with fruit preference (p=0.000, r=0.000). There was a significant difference of vegetable consumption between subjects who living in cities and subjects living in villages (p=0.039).
Keyword: college student, distance learning, vegetable and fruit consumption

Judul: The Relationship Between Eating Behavior and Physical Activity with Nutrition Status of IPB University Students During Distance Learning Period
Abstrak: Pandemi COVID-19 menyebabkan banyak perubahan pada hal yang bersifat besar untuk masyarakat seperti kesehatan masyarakat, ketenagakerjaan dan ekonomi, hingga yang kecil dan individual seperti gaya hidup. Mahasiswa program sarjana biasanya masuk ke dalam kelompok usia dewasa mudah yang mudah dipengaruhi oleh perubahan mental dan emosional. Metode Pembelajaran Jarak Jauh (PJJ) akibat pandemi dapat meningkatkan perubahan secara tidak langsung kepada tingkatan aktivitas fisik, perilaku makan, dan kebutuhan gizi. Desain penelitian ini adalah cross sectional dengan jumlah subjek 63 subjek mahasiswa Program Studi (Prodi) Ilmu Gizi dan Aktuaria IPB. Tujuan penelitian ini adalah mengetahui hubungan antara perilaku makan dan aktivitas mahasiswa Prodi Ilmu Gizi dan Aktuaria IPB dengan status gizi pada masa PJJ. Perilaku makan diukur menggunakan kuesioner Adult Eating Behavior Questionnaire, aktivitas fisik diukur dengan kuesioner IPAQ berdasarkan satuan MET menit/minggu. Uji Pearson dan Spearman menunjukkan terdapat hubungan signifikan antara perilaku makan dengan status gizi (p < 0,05) hanya pada dua subskala sifat nafsu makan (subskala rasa lapar (hunger) dan respons terhadap rasa lapar (satiety responsiveness) pada subjek Prodi Aktuaria, sedangkan pada subjek Prodi Ilmu Gizi tidak terdapat hubungan yang signifikan. Uji Spearman menunjukkan tidak adanya hubungan yang signifikan antara tingkat aktivitas fisik dengan status gizi pada subjek di kedua prodi., COVID-19 pandemic has caused many changes from public health, employment, and economy, to individual changes such as lifestyle. Undergraduate students usually fall into the age group of young adults who are easily influenced by mental and emotional changes. Distance Learning Methods due to the pandemic can make indirect changes to physical activity, eating behavior, and nutrition needs. The design of this study was cross sectional with a sample of 63 subjects from Nutrition and Actuarial Science Study Program IPB University. The purpose of this study was to determine the relationship between eating behavior and physical activity of Nutrition and Actuarial students of IPB with nutritional status during Distance Learning Period. Eating behavior was measured using the Adult Eating Behavior Questionnaire, physical activity levels were measured by the IPAQ questionnaire based on MET minutes/week. Pearson and Spearman tests showed that there was a significant relationship between eating behavior and nutritional status (p < 0,05) only on two subscales of appetitive traits (Hunger and Satiety Responsiveness) in Actuarial subjects, while there was no significant relationship between Nutrition Science subjects. Spearman’s test shows that there is no association between the level of physical activity and nutritional status in both study programs.
Keyword: appetitive traits, distance learning, eating behavior, physical activity, university students

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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