Judul: Struktur tegakan pasca penebangan pada sistem tebang pilih tanam jalur di konsesi hutan PT Erna Djuliawati
Abstrak: Forest harvesting causes the changes of forest ecosystem stability that can posses structure and species composition of forest stands. Stand structure is needed to show timber standing stock and describe stands regeneration ability. Stand structure can be described by the model of stand structure, there are family distribution and regression model. This research data was taken from the observation plot logged silviculture system of selective cutting and line planting of forest conditions based of post-logging at 12, 8, 6, 4, 2 years. This research aims to determine the model equations that can describe the timber standing stock in silviculture system of selective cutting and line planting and analyze the composition of the dominant species in natural regeneration. The results showed that the family distribution model of lognormal is the best model to describe the condition of stand structure in the area of PT Erna Djuliawati. The forest area has high preference of diversity index within species dominant at several species.
Keyword: Bogor Agricultural University (IPB), Silviculture System of Selective Cutting and Line Planting, Stand Structure Model, Family Distribution Model

Judul: Struktur Dan Komposisi Tegakan Pada Areal Bekas Tebangan Dengan Sistem Silvikultur Tebang Pilih Tanam Jalur (Tptj)  (Di Areal Iuphhk Pt. Erna Djuliawati, Kalimantan Tengah)
Abstrak: INTRODUCTION. The application of selective cutting and strip planting (TPTJ) as one of silviculture system is predicted to cause a lot of changes in structure and composition stand. This is related to the limit of commercial cut tree diameter which has to be more than 40 cm and with activity in form of the making of 3 meters wide of clear path for planting strip. The research objectives are : to get information about development of forest production area by observing its composition and forest structure using TPTJ system, as well as to get information about the effect of forest yield harvesting by TPTJ silviculture system on gap opening and residual stands. METHODS. The research conducted at three different forest conditions, were : primary forest, logged over area 0 years after logged (Et+0 forest) and primary forest which is newly done stripped. The method is using line transecht sampling by 100 m x 100 m. In that plot there are sub-plots, sub-plot of tree by 25 m x 20 m (22 m x 20 m after stripping), sub-plot of pole by 10 m x 10 m, sub-plot of sapling by 5 m x 5 m and sub-plot of seedling by 2 m x 2 m. RESULT AND DISCUSSION. The result showed that species composition at forest after logged lower almost in all vegetation leve (seedling, sapling, pole and tree). Forest after stripped showed that average of all vegetation level was increasing. It becaused of difference observed plot in the forest and also a part of LOA in 2007. The activity harvesting of commercial species at silviculture system of selective cutting and strip planting (TPTJ) causes land openness 30,83 to 46,20%. The effects of the application of selective cutting and strip planting (TPTJ) on soil physical and chemical properties include the increase of bulk density, the decrease of soil permeability, the decrease of the value of water availability from primary forest condition down to the condition of post path-making, the decrease of soil pH and cation exchange capacity (KTK). The applicatin of selective cutting and strip planting (TPTJ) in IUPHHK PT. Erna Djuliawati, Central Kalimantan on primary forest instigates changes in the composition and structure of stands as well as in some physical and chemical properties of soil. Keywords : Structure, Composition, Silviculture system, TPTJ
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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