Impact of Land-Use Change on Soil Carbon Dynamics in Tropical Peatland, West Kalimantan- Indonesia

The conversion of tropical peat forest to other land uses can reduce organic carbon (C) and stable C isotope (δ13C) of peat soil. This research aimed at analyzing the soil organic-C and δ13C of peatland with respect to maturity (fibric, hemic and sapric) in five types of peatland use, which included primary peat forest, secondary peat forest, shrubs, oil palm plantations, and cornfield in West Kalimantan. Analysis of peat soil samples includes organic C with Loss in ignition method and δ13C  using an isotope ratio mass spectrometry(IRMS) method. Organic-C at fibric was higher than hemic and sapric, respectively (57.2%, 57.0%, 56.4%), meanwhile, organic-C was the highest on primary peat forest, followed by on secondary peat forest, oil palm plantation, cornfield, and shrubs, respectively 57.1%, 57.0%, 56.4%, 56.0%. The cause of increasing and decreasing organic C and δ13C due to land-use change due to changes in vegetation, burning during tillage, and age of organic matter of peat soil. This condition causes the opening of natural peat ecosystems and changes in anaerobic to aerobic conditions.

Emisi Co2 Tanah Akibat Alih Fungsi Lahan Hutan Rawa Gambut Di Kalimantan Barat (Soil Emissions of Co2 Due to Land Use Change of Peat Swamp Forest at West Kalimantan)

This study aims to analyze peatland use change that caused changes soil emissions of CO2 at primary peat swamp forest (HP), secondary peat forest (HS), shrub (SB), oil palm plantations (KS) and corn field (KJ), and to analyze the influence of temperature and water-table depth to soil emission of CO2. Soil samples were taken from each five replications that accunt for 25 samples. Simultaneously with measurement of soil respiration measuremnts soil temperature. Field measurement is carried out twice at the beginning of dry season and the rainy season. The research shows that the highest and lowest soil emissions of CO2 at the two measurements are at KJ (6.512 ton ha-1 yr-1) and SB (1.698 ton ha-1 yr-1), and at KS (6.701 ton ha-1 yr-1) and SB (3.169 ton ha-1 yr-1), respectively. The highest and lowest temperature of peat soil the two measurements are at SB (27.78 oC) and HP (22.78 oC), and at KS (29.08 oC) dan HP (26.56 oC). Also the highest and lowest water-table depth of peat soil are at KJ (56.2 cm) and SB (32.1 cm). The factors caused to differences of CO2 emissions are soil temperature, water-table depth and land cultivation which caused changing of peat-soil properties such as organic-C stock, soil pH and peat maturity

KARAKTERISTIK FISIK LAHAN AKIBAT ALIH FUNGSI LAHAN HUTAN RAWA GAMBUT

Tujuan penelitian ini adalah mengamati karakteristik serasah dan biomasa tanaman pada lima tipe lahan (hutan rawa gambut primer-HP, hutan gambut sekunder-HS, semak belukar-SB, kebun sawit-KS, kebun jagung-KJ), seperti berat basah, berat kering, kadar air, kadar abu, C-organik dan kandungan C, sebagai dampak perubahan penggunaan lahan. Penelitian ini dilakukan pada lahan gambut di Rasau Jaya-Propinsi Kalimantan Barat. Hasil penelitian ini menunjukkan bahwa berat basah, berat kering, kadar air, kadar abu dan C-organik biomasa pada KJ lebih tinggi daripada KS, SB, HS dan HP. Sedangkan serasah HP mempunyai kandungan C lebih tinggi daripada KS, HS, SB dan KJ. Kata kunci : biomasa tanaman, lahan gambut, perubahan penggunaan lahan, serasa

11q13 amplification status and human papillomavirus in relation to p16 expression defines two distinct etiologies of head and neck tumours

Two distinct etiologies of head and neck squamous cell carcinoma (HNSCC) have been proposed, DNA damage owing to tobacco and alcohol exposure and human papillomavirus (HPV) oncogene-mediated transformation. Common genetic alterations in HNSCC include TP53 mutations, 11q13 amplification (amp) and CDKN2A/p16 mutations or promoter methlyation. However, in HPV+ HNSCC it is frequent to observe wild-type TP53 and expression of p16. The relationship of this unusual pattern with 11q13 amp has not been tested. In a retrospective study on 125 HNSCC patients, only 17% (five out of 30) of HPV+ vs 44% (39 out of 89) of HPV − tumours expressed 11q13 amp (adjusted odds ratio (OR)=0.2, 95% confidence interval (CI)=0.1–0.6). A subpopulation of tumours (n=69) were classified according to the three molecular markers, TP53, p16 and 11q13 amp. In addition to wild-type TP53, and p16 expression, HPV+ tumours were more likely not to be amplified at 11q13 (OR=6.5, 95% CI=1.8–23.9). As HPV+ HNSCC lack the genetic alterations which are common in other tumours, we hypothesise that HPV infection may represent an early event in the HNSCC carcinogenic process, thus suggesting a distinct molecular pathway

New infant cranium from the African Miocene sheds light on ape evolution

The evolutionary history of extant hominoids (humans and apes) remains poorly understood. The African fossil record during the crucial time period, the Miocene epoch, largely comprises isolated jaws and teeth, and little is known about ape cranial evolution. Here we report on the, to our knowledge, most complete fossil ape cranium yet described, recovered from the 13 million-year-old Middle Miocene site of Napudet, Kenya. The infant specimen, KNM-NP 59050, is assigned to a new species of Nyanzapithecus on the basis of its unerupted permanent teeth, visualized by synchrotron imaging. Its ear canal has a fully ossified tubular ectotympanic, a derived feature linking the species with crown catarrhines. Although it resembles some hylobatids in aspects of its morphology and dental development, it possesses no definitive hylobatid synapomorphies. The combined evidence suggests that nyanzapithecines were stem hominoids close to the origin of extant apes, and that hylobatid-like facial features evolved multiple times during catarrhine evolution