289 research outputs found
Biomass Equations for Tropical Tree Plantation Species Using Secondary Data from the Philippines
Estimation of the magnitude of sinks and sources of carbon requires reliable estimates of the biomass of forests and of individual trees. Equations for predicting tree biomass have been developed using secondary data involving destructive sampling in plantations in several localities in the Philippines. These equations allow estimates of carbon sequestration to be made at much lower cost than would be incurred if detailed stand inventories were undertaken. The species included in the study reported here include Gmelina arborea, Paraserianthes falcataria, Swietenia macrophylla and Dipterocarp species in Mindanao; Leucaena leucocephala from Laguna, Antique, Cebu, Iloilo, Rizal, and Ilocos Sur, and Acacia mangium, Acacia auriculiformis and G. arborea in Leyte. Non-linear regression was used to derive species-specific, site-specific and generic equations between yield and diameter of the form y = aDb. Equations were evaluated based on the correlation coefficient, standard error of the estimate and residual plots. Regressions resulted to high r values (>0.90). In some cases, non-homogeneous variance was encountered. The generic equation improved estimates compared with models used in previous studies
Carbon Storage and Sequestration Potential of Smallholder Tree Farms on Leyte Island, the Philippines
The role of terrestrial ecosystem in mitigating the effects of climate change entails the assessment of carbon stocks in various pools. This study predicts the carbon storage and sequestration potential of common tree farm species in Leyte Island, the Philippines. Data gathered from field measurements has been used to fit the Chapman-Richards growth function to predict the volume and biomass increment of Gmelina arborea and Swietenia macrophylla tree farms until they reached their respective rotation ages. Biomass and carbon density values are found to vary with age, type of species, site conditions and silvicultural treatments applied in the stand. Although differences in year when the trees were planted had no relation with its soil carbon storage, this pool had greater storage capacity than the above-ground biomass and roots. The average maximum growth was attained after 10 years for G. arborea and 13 years for S. macrophylla. Volume growth started to slow down when the tree species reached almost half its rotation age. The same trend was observed for the biomass and carbon density of each farm. The maximum mean annual increment of both species was attained before the expected maximum growth year. Growth increment decreased as the species reached their rotation age. The total C storage capacity of a 15-year-old G. arborea tree farm was estimated at 64 MgC/ha while that of a 25-year-old S. macrophylla was estimated at 159 MgC/ha. The average carbon sequestration rate of both species was 5 MgC/ha/yr which is lower than the average rate of most tree plantation species in the Philippines. With almost 2 M ha of grasslands in the country, establishing tree farms is a strategy to attain the national goal on sustainable development and at the same time reduce the greenhouse gases (GHGs) emissions
Biomass equations for tropical tree plantation species in young stands using secondary data from the Philippines
Estimation of the magnitude of sinks and sources of carbon requires reliable estimates of the biomass of forests and of individual trees. Equations for predicting tree biomass have been developed using secondary data involving destructive sampling in plantations (mostly less than 10 years of age) in several localities in the Philippines. These equations allow estimates of carbon sequestration to be made at much lower cost than would be incurred if detailed stand inventories were undertaken. The species included in the study reported here include Gmelina arborea Roxb., Paraserianthes falcataria (L.) Nielsen Swietenia macrophylla King and Dipterocarp species in Mindanao, and Leucaena leucocephala de Wit from Laguna, Antique, Cebu, Iloilo, Rizal, and Ilocos Sur. Non-linear regression was used to derive species-specific, site-specific and generic equations between yield and diameter of the form y = D. Equations were evaluated based on the correlation coefficient, standard error of estimate and residual plots. Regressions resulted in high r values (>0.90). In some cases, non-homogeneous variance was encountered. The generic equation improved estimates compared with models used in previous studies
Carbon storage and sequestration potential of small holder tree farms
The role of terrestrial ecosystem in mitigating the effects of climate change entails the assessment of carbon stocks in various pools. This study predicts the carbon storage and sequestration potential of common tree farm species in Leyte Island, the Philippines. Data gathered from field measurements has been used to fit the Chapman-Richards growth function to predict the volume and biomass increment of Gmelina arborea and Swietenia macrophylla tree farms until they reached their respective rotation ages. Biomass and carbon density values are found to vary with age, type of species, site conditions and silvicultural treatments applied in the stand. Although differences in year when the trees were planted had no relation with its soil carbon storage, this pool had greater storage capacity than the above-ground biomass and roots. The average maximum growth was attained after 10 years for G. arborea and 13 years for S. macrophylla. Volume growth started to slow down when the tree species reached almost half its rotation age. The same trend was observed for the biomass and carbon density of each farm. The maximum mean annual increment of both species was attained before the expected maximum growth year. Growth increment decreased as the species reached their rotation age. The total C storage capacity of a 15-year-old G. arborea tree farm was estimated at 64 MgC/ha while that of a 25-year-old S. macrophylla was estimated at 159 MgC/ha. The average carbon sequestration rate of both species was 5 MgC/ha/yr which is lower than the average rate of most tree plantation species in the Philippines. With almost 2 M ha of grasslands in the country, establishing tree farms is a strategy to attain the national goal on sustainable development and at the same time reduce the greenhouse gases (GHGs) emissions
Marketing Benefits Derived from Clustering: the Case of Vegetable Clusters in Mindanao
One of the most limiting constraints for improving the profitability of smallholder vegetable farmers is poor marketing. With the lack of knowledge and inability to negotiate with downstream buyers, farmers have little option other than to sell their products to the traditional market. To facilitate access to technical information, credit and institutional markets, smallholder farmers are forming collaborative marketing groups. Clustering is one form of collaborative marketing in which smallholder farmers are organized into small groups within a defined territory or geographic area. Using the CRS Eight Step Plan for Agro-enterprise Development, 29 clusters were formed in three provinces in the Southern Philippines. This study explores the various marketing benefits smallholder farmers have achieved after joining the cluster. After interviewing 61 vegetable farmers from 10 clusters using a structured questionnaire, results show that upon joining the cluster, farmers became more aware of their buyer’s preference for product quality and gained knowledge on how to properly handle and package their produce. Cluster farmers increased their income from vegetable farming by selling a greater product variety, a larger volume and gaining access to high value markets
Timing to achieve the highest rate of pCR after preoperative radiochemotherapy in rectal cancer: a pooled analysis of 3085 patients from 7 randomized trials
Purpose: Optimal timing of surgery after neoadjuvant chemoradiotherapy (Nad-CRT) is still controversial in locally advanced rectal cancer (LARC). The primary goal of this study was to determine the best surgical interval (SI) to achieve the highest rate of pathological complete response (pCR) and secondly to evaluate the effect on survival outcomes according to the SI.Patients and methods: Patients data were extracted from the international randomized trials: Accord12/0405, EORTC22921, FFCD9203, CAO/ARO/AIO-94, CAO-ARO-AIO-04, INTERACT and TROG01.04. Inclusion criteria were: age >= 18, cT3-T4 and cN0-2, no clinical evidence of distant metastasis at diagnosis, Nad-CRT followed by surgery.Pearson's Chi-squared test with Yates' continuity correction for categorical variables, the MannWhitney test for continuous variables, Mann-Kendall test, Kaplan-Meier curves with log-rank test, univariate and multivariate logistic regression model was used for data analysis. Results: 3085 patients met the inclusion criteria. Overall, the pCR rate was 14% at a median SI of 6 weeks (range 1-31). The cumulative pCR rate increased significantly when SI lengthened, with 95% of pCR events within 10 weeks from Nad-CRT.At univariate and multivariate logistic regression analysis, lengthening of SI (p< 0.01), radiotherapy dose (p< 0.01), and the addition of oxaliplatin to Nad-CRT (p< 0.01) had a favorable impact on pCR. Furthermore, lengthening of SI was not impact on local recurrences, distance metastases, and overall survival.Conclusion: This pooled analysis suggests that the best time to achieve pCR in LARC is at 10 weeks, considering that the lengthening of SI is not detrimental concerning survival outcomes. (C) 2020 Elsevier B.V. All rights reserved.</p
An amphitropic cAMP-binding protein in yeast mitochondria
ABSTRACT: We describe the first example of a mitochondrial protein with a covalently attached phos-phatidylinositol moiety acting as a membrane anchor. The protein can be metabolically labeled with both stearic acid and inositol. The stearic acid label is removed by phospholipase D whereupon the protein with the retained inositol label is released from the membrane. This protein is a cAMP receptor of the yeast Saccharomyces cereuisiae and tightly associated with the inner mitochondrial membrane. However, it is converted into a soluble form during incubation of isolated mitochondria with Ca2+ and phospholipid (or lipid derivatives). This transition requires the action of a proteinaceous, N-ethylmaleimide-sensitive component of the intermembrane space and is accompanied by a decrease in the lipophilicity of the cAMP receptor. We propose that the component of the intermembrane space triggers the amphitropic behavior of the mitochondrial lipid-modified CAMP-binding protein through a phospholipase activity. Only in recent years specific fatty acids have been recog-nized to play important roles in the association of proteins with membranes. Both noncovalent and covalent interactions be-tween fatty acids and proteins have been reported. Among the latter are GTP-binding proteins (Molenaar et al., 1988)
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