Judul: Carbon Storage Estimation in Mangrove Above Ground Biomass in Kaliwlingi Village, Brebes.
Abstrak: Desa Kaliwlingi, Kabupaten Brebes, Jawa Tengah, memiliki sabuk hijau mangrove di pesisirnya yang berperan penting dalam penyimpanan karbon biru. Penelitian ini bertujuan mengamati vegetasi mangrove yang ada di Desa Kaliwlingi, serta mengestimasi simpanan karbon dan biomassa above ground (BAG). Survei mangrove pada 50 plot berukuran 10 m x 10 m dilakukan pada Oktober–November 2023. Estimasi biomassa dan simpanan karbon menggunakan metode non destructive sampling (Dharmawan dan Siregar 2008; Dharmawan 2010; SNI 7724: 2011) yang didasari oleh data diameter at breast height (DBH). Hasil penelitian mendapati ada dua spesies mangrove di Desa Kaliwlingi, yaitu Rhizophora mucronata dan Avicennia marina dengan kerapatan sebesar 2.632 ind/ha untuk pohon dan 2.808 ind/ha untuk anakan. Total simpanan karbon pada mangrove dipengaruhi oleh biomassa above ground dan diameter tegakan (DBH). Simpanan karbon dan BAG mangrove terbesar terdapat pada kelas DBH 9,08–24,04 cm (295,86 ton C/ha dan 629,49 ton/ha), sedangkan yang terendah pada DBH 1,34–5,30 cm (26,10 ton C/ha dan 55,54 ton/ha). Potensi karbon mangrove Desa Kaliwlingi belum mempertimbagkan nilai simpanan di bawah substrat., Kaliwlingi, a village in Brebes Regency of Central Java Province, features mangrove green belts along its coastline and of importance for blue carbon storage. The aim of this study was to conduct mangrove vegetation assessment at village scale, also to estimate above ground biomass (AGB) and carbon storage. Mangrove assessment was carried out in October–November 2023, to identify and measure diameter at breast height (DBH) at 50 plots, each with 10 m × 10 m quadrant. Biomass and carbon storage estimation was utilizing non-destructive methods by Dharmawan and Siregar 2008; Dharmawan 2010; and SNI 7724: 2011. Two mangrove species were observed in Kaliwlingi, namely Rhizophora mucronata and Avicennia marina, with density of 2.632 ind/ha for trees and 2.808 ind/ha for saplings. Carbon storage in mangroves is function of DBH and biomass. The highest stored carbon potential and biomass was observed for DBH range class of 9,08–24,04 cm (295.86 tons C/ha and 629.49 tons/ha), while the lowest at DBH 1,34–5,30 cm range (26,10 tons C/ha and 55,54 tons/ha). Blue carbon potential from mangroves at Kaliwlingi Village has yet to consider below ground carbon storage.
Keyword: biomassa, diameter, mangrove, simpanan karbon, desa kaliwlingi

Judul: Mapping of Mangrove Area Changes in Kaliwlingi Village, Brebes Regency, Jawa Tengah Province
Abstrak: Berdasarkan penelitian sebelumnya, Pesisir Desa Kaliwlingi, Kabupaten Brebes mengalami abrasi sepanjang 7 km dengan luas 186 hektar atau 30% dari luas abrasi di Kabupaten Brebes. Hal tersebut diakibatkan oleh adanya konversi lahan mangrove menjadi tambak yang dapat merusak lahan pantai. Peningkatan abrasi setiap tahun mendorong masyarakat peduli lingkungan melakukan kegiatan konservasi lahan mangrove untuk mengurangi abrasi dan akresi, disepanjang pantai. Penelitian ini bertujuan untuk mengetahui nilai threshold yang memisahkan mangrove dengan non-mangrove dan luasan mangrove. Penelitian ini menggunakan data citra Sentinel-2A dan data lapang hasi survei. Data satelit diolah dan dianalisis menggunakan algoritma Mangrove Vegetation Index (MVI). Simple random sampling digunakan untuk menentukan pengambilan titik lapang yang digunakan sebagai acuan klasifikasi kelas mangrove dan non-mangrove dari citra satelit. Uji akurasi algoritma MVI menggunakan matriks konfusi, dan koefisien kappa. Hasil penelitian menunjukan jenis mangrove di sekitar 4 stasiun penelitian adalah Avicennia marina, Avicennia alba, dan Rhizophora mucronata. Hasil pemetaan menggunakan algoritma MVI menunjukkan nilai threshold MVI mangrove berkisar antara 2,3 hingga 19,54, sementara nilai non-mangrove adalah <2,3 dan >19,54. Luasan mangrove dari tahun 2016 hingga 2022 mengalami peningkatan sebesar 27,62 ha. Uji akurasi algoritma MVI menunjukkan hasil yang baik dengan overall accuracy 86,81% dan koefisien kappa sekitar 0,73., Based on previous research, Kaliwlingi Village Coastal, Brebes Regency experienced abrasion along 7 km with an area of 186 hectares or 30% of the abrasion area in Brebes Regency. It happened due to the conversion of mangrove land into ponds that can damage coastal land. The increase in abrasion every year encourages people to care about the environment to carry out mangrove land conservation activities to reduce abrasion and accretion, along the coastal. This study aims to determine threshold value that separates class between mangroves and non-mangrove area, then estimate the changing area of mangrove. This study used Sentinel-2A imagery datas and survey field data. Satellite data processed and analyzed, was using the Mangrove Vegetation Index (MVI) algorithm. Simple random sampling used to determine the selection of field points used as a reference for classifying mangrove and non-mangrove classes from satellite images. Test the accuracy of the MVI algorithm used a fusion matrix, and a kappa coefficient. The results showed that the types of mangroves around 4 research stations were Avicennia marina, Avicennia alba, and Rhizophora mucronata. The mapping results used the MVI algorithm showed that the threshold value of mangrove MVI ranged from 2,30 to 19,54, while non-mangrove values were <2,30 and >19,54. The area of mangroves from 2016 to 2022 has increased by 27,62 ha. The MVI algorithm accuracy test showed good results with an overall accuracy was 86,81% and a kappa coefficient was 0,73.
Keyword: Abrasion, Mangrove, MVI, Non-mangrove, Threshold

Judul: Comparison of HIV Model with and without Time Delay
Abstrak: Acquired immunodeficiency syndrome (AIDS) is the reduction of the human immune system. AIDS is caused by human immunodeficiency virus (HIV). No medicine has been found for this desease until recently. An AIDS therapy is usually performed with highly active antiretroviral therapy, namely reverse transcriptase inhibitors, protease inhibitors and combination of both. Various models have been developed to explain the immune system of patients with AIDS, namely the HIV, response and the time delay model. This paper discusses the comparison between the dynamics of the HIV virus, the dynamic response of protease inhibitors and dynamics of time delay. The dynamics model of HIV is influenced by the level of white blood cells produced and the rate of its death. Dynamics of protease inhibitors on the response and the time delay model is influenced by the death rate of infected white blood cells and the failure rate of treatment.
Keyword: