145 research outputs found
Organizing for Results: The Philippine Agricultural Sector
While agriculture sector has performed poorly during the 1980s, it still remains as an important sector in the country. This paper proposes a set of policy and institutional reforms to improve the sector’s performance focusing on three aspects: completion of the sector’s deregulation, improvement of the allocation of public funds across policy instruments and restructuring the agricultural bureaucracy. These reforms will put down the foundation for an efficient incentive and institutional structure of support-service delivery.agriculture sector
Organizing for results : the Philippine agricultural sector
Philippine agriculture performed poorly in the 1980s. The average annual growth rate
declined from 4.8 percent in the 1970s to 2.1 percent, lower than the population growth rate.
As a result, export surpluses dwindled and agricultural imports rose. Although depressed world
commodity markets undoubtedly lowered agriculture's growth performance, other Asian
countries managed to grow faster, and most of them at a rate even higher than in the 1970s
(Table 1). The country's poor performance can be largely attributed to the slow growth of crop
productivity, eroding Philippine competitive advantage (Fig. la). Among the traditional
commodities, only yields of rice and, to a lesser extent, corn grew significantly. As Philippine
coconut and sugar yields stagnated, Malaysian oil palm and Thai sugar expanded their shares
of world markets. (Fig. lb).
With the closing of the land frontier and continued high population growth, agricultural
development will have to come from technological change and irrigation expansion that can
increase productivity and effective crop area. Yet government interventions in agriculture over
the past four decades have relied primarily on short-term price and trade regulations to lower
food prices, raise farmers' income, and achieve food self-sufficiency; regulations are easier to
implement, have short-term impact, and generate resources for the agency concerned. Market
regulations, however, have often protected consumers at the expense of farmers, raised
production costs, distorted incentives against commodities where our comparative advantage
lies,and misallocated government resources from growth-enhancing investments to unproductive
bureaucratic costs without achieving their stated objectives. On the other hand, too few resources
have been allocated to the more cost-effective, sustainable long-term policy instruments that raise
agricultural productivity and lower unit cost of production, such as agricultural research and
irrigation, to attain these conflicting objectives
Mechanism of Insulin Emission in Matrix Assisted Laser Ionization
In the present paper the emission of intact insulin quasi-molecular ion [M+H] + during laser ablation (MALDI) is studied. It was observed in particular that the insulin TOF molecular peak increases as the laser power increases. The DE-Vestal method for the initial velocity measurements was improved theoretically including the distance (d0) until the free expansion regime can be considered. According to the present analysis, the v0 parameter given by the DE-Vestal method is interpreted as the initial velocity that the desorbed ion would have if no collision occurs in the plasma. The improved method interprets v 0 as the "final" initial velocity, i.e., as the velocity that the desorbed ions have when the plasma free expansion starts and, effectively, collisions no longer occur. The new method allows also the determination of d 0 , the distance to the solid when the free expansion starts. The data fitting shows that the distance (d0) has a linear dependence on the laser's intensity. Extrapolation of these values gives I = 0.69 G W cm −2 as the minimum energy density necessary to produce high density plasma during the insulin ions desorption when using αCHCA matrix
Oscillatory behaviour on a non-autonomous hybrid SIR-Model
We study the impact of some abstract agent intervention on the disease spread modelled by a SIR-model with linear growth infectivity. The intervention is meant to decrease the infectivity, which are activated by a threshold on the number of infected individuals. The coupled model is represented as a nonlinear non-autonomous hybrid system. Stability and reduction results are obtained using the notions of non-autonomous attractors, Bohl exponents, and dichotomy spectrum. Numerical examples are given where the number of infected individuals can oscillate around a equilibrium point or be a succession of bump functions, which are validated with a tool based on the notion of delta-complete decision procedures for solving satisfiability modulo theories problems over the real numbers and bounded delta-reachability. These findings seem to show that hybrid SIR-models are more flexible than standard models and generate a vast set of solution profiles. It also raises questions regarding the possibility of the agent intervention been somehow responsible for the shape and intensity of future outbreaks.publishe
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The bacterial communities of Alaskan mosses and their contributions to N-2-fixation
Background
Mosses in high-latitude ecosystems harbor diverse bacterial taxa, including N2-fixers which are key contributors to nitrogen dynamics in these systems. Yet the relative importance of moss host species, and environmental factors, in structuring these microbial communities and their N2-fixing potential remains unclear. We studied 26 boreal and tundra moss species across 24 sites in Alaska, USA, from 61 to 69° N. We used cultivation-independent approaches to characterize the variation in moss-associated bacterial communities as a function of host species identity and site characteristics. We also measured N2-fixation rates via 15N2 isotopic enrichment and identified potential N2-fixing bacteria using available literature and genomic information.
Results
Host species identity and host evolutionary history were both highly predictive of moss microbiome composition, highlighting strong phylogenetic coherence in these microbial communities. Although less important, light availability and temperature also influenced composition of the moss microbiome. Finally, we identified putative N2-fixing bacteria specific to some moss hosts, including potential N2-fixing bacteria outside well-studied cyanobacterial clades.
Conclusions
The strong effect of host identity on moss-associated bacterial communities demonstrates mosses’ utility for understanding plant-microbe interactions in non-leguminous systems. Our work also highlights the likely importance of novel bacterial taxa to N2-fixation in high-latitude ecosystems.
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Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation
Background: Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this.
Methodology/Principal Findings: A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum.
Conclusions: A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine serum
Characterising patterns of engagement of different participants in a public STEM-based analysis project
An analysis project undertaken in the context of a historic visitor site is described. The project offered different types of opportunity for scientific working, and involved four distinct groups of participants. Two distinguishing features of the different groups of participants were their primary motivation for engagement with the activity, and their level of previous engagement with formal science education. Participants in different parts of the project were assessed as to their level of science capital (Archer et al., 2015). Drawing upon engagement theory, the observable behaviours were used as an indicator of engagement and then categorised according to Pearson's (2010) taxonomy. The analysis showed that learner engagement was exhibited at different levels by the different categories of participants, with higher levels of engagement exhibited by participants with a higher level of science capital. Although there was general correlation between the level of science capital and the proportion of higher engagement learning behaviours, one group of participants deviated from this trend. The findings indicate that the level of science capital is a key determinant of engagement and associated learning behaviours, but did not completely account for participants’ engagement in the science outreach activity
Portuguese validation of the Internet Addiction Test: An empirical study
Abstract
Background and aims
Research into Internet addiction (IA) has increased greatly over the last decade. Despite its various definitions and general lack of consensus regarding its conceptualisation amongst researchers, instruments for measuring this phenomenon have proliferated in a number of countries. There has been little research on IA in Portugal and this may be partly due to the absence of standardised measurement tools for assessing IA.
Methods
This study attempted to address this issue by adapting a Portuguese version of the Internet Addiction Test (IAT) via a translation-back translation process and Confirmatory Factor Analysis in a sample of 593 Portuguese students that completed a Portuguese version of the IAT along with questions related to socio-demographic variables.
Results
The findings suggested that the IAT appears to be a valid and reliable instrument for measuring IA among Portuguese young adults as demonstrated by its satisfactory psychometric properties. However, the present findings also suggest the need to reword and update some of the IAT's items. Prevalence of IA found in the sample was 1.2% and is discussed alongside findings relating to socio-demographic correlates. Limitations and implications of the present study are also discussed.
Conclusions
The present study calls for a reflection of the IAT while also contributing to a better understanding of the basic aspects of IA in the Portuguese community since many health practitioners are starting to realise that Internet use may pose a risk for some individuals
Overexpression of the Endoplasmic Reticulum Chaperone BiP3 Regulates XA21-Mediated Innate Immunity in Rice
Recognition of pathogen-associated molecular patterns by pattern recognition receptors (PRRs) activates the innate immune response. Although PRR-mediated signaling events are critical to the survival of plants and animals, secretion and localization of PRRs have not yet been clearly elucidated. Here we report the in vivo interaction of the endoplasmic reticulum (ER) chaperone BiP3 with the rice XA21 PRR, which confers resistance to the Gram negative bacterium, Xanthomonas oryzae pv. oryzae (Xoo). We show that XA21 is glycosylated and is primarily localized to the ER and also to the plasma membrane (PM). In BiP3-overexpressing rice plants, XA21-mediated immunity is compromised, XA21 stability is significantly decreased, and XA21 proteolytic cleavage is inhibited. BiP3 overexpression does not affect the general rice defense response, cell death or brassinolide-induced responses. These results indicate that BiP3 regulates XA21 protein stability and processing and that this regulation is critical for resistance to Xoo
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