Judul: Determinants and Norm of Circulant and Left Circulant Matrix with Entries of Circulant Numbers
Abstrak: Matriks circulant adalah suatu matriks berukuran n×n yang dibentuk dari n vektor dan setiap entri dari baris sebelumnya bergeser satu posisi ke kanan pada baris berikutnya. Pada karya ilmiah ini ditentukan determinan dan norm dari matriks circulant dan circulant kiri dengan entri bilangan Tribonacci. Dari hasil pembuktian diperoleh bahwa determinan dari matriks circulant merupakan hasil perkalian dari semua nilai eigen pada matriks tersebut, norm jumlah kolom maksimum adalah jumlah maksimum dari jumlah kolom absolut, norm jumlah baris maksimum adalah jumlah maksimum dari jumlah baris absolut, dan Frobenius norm adalah akar kuadrat dari jumlah kuadrat absolut setiap elemen matriks circulant. Kemudian diberikan penghitungan determinan, norm jumlah kolom maksimum, norm jumlah baris maksimum, dan Frobenius norm dengan entri bilangan Tribonacci untuk matriks circulant berukuran 2×2 dan 3×3., Circulant matrix is an n × n matrix formed from n vectors and each row is a cyclic shift of the row above to the right. In this scientific work we determine the determinants and norms of the circulant and left circulant matrix involving Tribonacci numbers. From the results of the proof it is obtained that the determinant of the circulant matrix is product of all eigenvalue in the matrix, the maximum coloumn sum matrix norm is the maximum number of absolute column sums, the maximum row sum matrix norm is the maximum number of absolute row sums, and the Frobenius norm is the square root of the absolute squared number of each circulant matrix element. Then given the calculation from the determinant, the maximum coloumn sum matrix norm, the maximum row sum matrix norm, and the Frobenius norm involving Tribonacci numbers for 2×2 and 3×3 circulant matrix.
Keyword: Tribonacci numbers, Determinants, Circulant Matrices, Left Circulant Matrices, The Frobenius Norms

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