Judul: The Determinant Formulation of Circulant Matrix with entry of the 2nd Order Recurrence Relation Number Formasi Jangkar
Abstrak: Matriks circulant merupakan matriks segi yang entri-entri pada setiap barisnya sama dengan entri-entri pada baris sebelumnya dan bergeser posisi ke kanan. Entri-entri dari matriks circulant dapat diisi dengan berbagai entri, salah satunya adalah bilangan-bilangan yang membentuk suatu barisan bilangan. Barisan bilangan dapat dibuat dengan menggunakan relasi rekurensi orde-2. Pada karya ilmiah ini, relasi rekurensi tersebut didefinisikan sebagai \[J_{n}=2J_{n−1}+3J_{n−2}\] dengan syarat awal \[J_0=3,J_1=1,n≥2,\] dan membentuk barisan bilangan yang dinamakan Formasi Jangkar. Kemudian, determinan matriks circulant dengan entri barisan bilangan Formasi Jangkar dapat dirumuskan secara eksplisit menggunakan sifat-sifat determinan sederhana yang berkaitan dengan operasi baris dasar., The circulant matrix is a faceted matrix where the entries in each row are the same as the entries in the previous row and shift position to the right. The entries of the circulant matrix can be filled with various entries, one of which is the numbers that form a sequence of numbers. Sequences of numbers can be constructed by a recurrence relation of order-2. In this scientific work, the recurrence relation is defined as \[J_{n}=2J_{n−1}+3J_{n−2}\] with initial condition \[J_0=3,J_1=1,n≥2,\] and form a sequence of numbers called Formasi Jangkar. Then, the determinant of the circulant matrix with entry the Formasi Jangkar can be formulated eksplicitly using the properties of determinants based on elementary row operations.
Keyword: bilangan Formasi Jangkar, determinan, matriks circulant, operasi baris  dasar, Relasi rekurensi, circulant matrix, elementary row operation, Formasi  Jangkar number, recurrence relation, determinant

Judul: Perhitungan Determinan dan Invers Matriks Circulant dengan Entri Jacobsthal Numbers Menggunakan Operasi Baris atau Kolom Dasar
Abstrak: Matriks circulant merupakan matriks segi berukuran n × n dengan setiap diagonal mempunyai elemen yang sama serta elemen matriks pada baris sebelumnya digeser satu posisi ke kanan pada baris berikutnya. Salah satu sifat yang dimiliki matriks circulant, yaitu inversnya juga berupa circulant. Entri-entri dari matriks circulant dapat menggunakan entri dengan berbagai bilangan, salah satunya adalah Jacobsthal Number. Pada karya ilmiah ini ditentukan perhitungan determinan dan invers matriks circulant dengan entri Jacobsthal Numbers. Pembuktian formulasi determinan matriks circulant dengan entri Jacobsthal Numbers didapatkan dari serangkaian operasi baris dasar sehingga terbentuk matriks segitiga atas, sedangkan formulasi invers matriks didapatkan berdasarkan sifat-sifat ekuivalensi matriks dari hasil serangkaian operasi baris dan kolom dasar sehingga terbentuk matriks diagonal. Matrix circulant is a n × n triangular matrix with the identical elements on each diagonal and the elements from the previous row relocated one place to the right in the next row. The circulant's entries can contain a variety of numbers, one of which is the Jacobsthal numbers. In this scientific work, it is determined the calculation of the determinant and the inverse of the circulant with the entry of Jacobsthal Numbers. The determinant formulation is obtained from a series of elementary row operations to get an upper triangular matrix, and the inverse formulation is based on the matrix equivalence properties of a series of elementary row and column operations to get a diagonal matrix.
Keyword: elementary row or column operation, circulant matrices, determinant, invers, jacobsthal numbers

Judul: Durability of Specific Immunoglobulin (Ig) Y Againts Influenza and Covid-19 in Sunscreen
Abstrak: The benefit of specific immunoglobulin Y (Ig Y) as an active ingredient in personal care products such as sunscreen has not been properly studied. Our study aims to evaluate the reliability of specific IgY against influenza and the COVID-19 virus in a sample sunscreen product. Specific IgY influenza and COVID-19 viruses were inserted in the sample sunscreen at two concentrations of 0.1% and 0.25%. Three treatments were observed: control (C) sunscreen without IgY, treatment 1 (T1) sunscreen with 0.1% IgY, and treatment 2 (T2) sunscreen with 0.25% IgY. Organoleptic observations were carried out to monitor changes in aroma, color, and texture, and sunscreen sampling was done every week for 6 weeks. The durability of IgY was evaluated using an enzyme-linked immunosorbent assay (ELISA) and a neutralization assay. Organoleptic observation from weeks 1 to 6 showed consistency in its aroma, color, and texture. Enzyme-linked immunosorbent assay and neutralization assay (NA) results of the T1 and T2 groups showed negative results except for sample T1 at week 5, which showed a positive result in the Influenza A ELISA. Based on the results, it seems that IgY concentrations of 0.1% or 0.25% were not optimal. However, this negative result might be due to low concentration of the IgY and the presence of beeswax, which inhibits IgY and causes it to dissolve in distilled water, thus preventing it from being detected in the assay.
Keyword: Immunoglobulin Y, Sunscreen, Influenza, COVID-19, Biological Activity