THE EFFECT OF SOIL CONSERVATION ON TECHNICAL EFFICIENCY: EVIDENCE FROM CENTRAL AMERICA

This study evaluates technical efficiency (TE) levels for rural households under high and low levels of investments in soil conservation in El Salvador and Honduras. To correct for potential self-selectivity bias a household-level switching regression framework is implemented to estimate separate stochastic production frontiers for the two groups of households under analysis. The main results indicate that a systematic difference exists between the two studied groups. Specifically, households with higher levels of investments in soil conservation show higher average TE than those with a lower level of investments. Constrains in the rural land and credit markets appear to be the reason behind these differences. Our estimations indicate that for farms with lower levels of investments in soil conservation access to credit is a significant factor explaining the sources of inefficiency. Conversely, households with higher levels of investments in soil conservation present the highest partial output elasticity for land, the highest levels of TE and the smallest farms. This result could suggest the presence of a market failure in the land market which is denying access to land to the more efficient producers.Land Economics/Use,

FARM BENEFITS AND NATURAL RESOURCE PROJECTS IN HONDURAS AND EL SALVADOR

A model of conservation adoption, diversification and household income, including farm and off-farm sources was formalized, wherein households simultaneously allocate assets to different activities. The mapping of assets to household income through both off and on farm activities can conceptually be considered as a production process, with assets corresponding to factors of production and income as the output. Either adoption of conservation technologies and farm output diversification are influenced by participation in natural resource management programs. Therefore, these technological improvements should foster farm production and productivity and, consequently, should be reflected in a greater household income,. Finally, household income improvement is considered a necessary condition for sustainability of the changes introduced by the projects. Overall, the results indicate that the variables more directly reflecting land allocation, such as area with staples and cash crops, output diversification and conservation practices are associated with the greatest gains in household income. Output diversification significantly decreases income from staple crops and greatly increases cash crop income. These results reaffirm the strategic role of diversification in fighting rural poverty. However, gains stemming from a more diversified income portfolio do not occur without cost, since an extra item added to the farm plan implies a reduction in the production of corn and beans (staples). This trade-off between diversification and subsistence food production suggests that switching to a more market-oriented production pattern may increase household food insecurity.Consumer/Household Economics,

Soil conservation and technical efficiency among hillside farmers in Central America: a switching regression model

The main objective of this paper is to evaluate and analyse technical efficiency (TE) levels for hillside farmers under different levels of adoption of soil conservation in El Salvador and Honduras. A switching regression model is implemented to examine potential selectivity bias for high and low level adopters, and separate stochastic production frontiers, corrected for selectivity bias, are estimated for each group. The main results indicate that households with above-average adoption show statistically higher average TE than those with lower adoption. Households with higher adoption have smaller farms and display the highest partial output elasticity for land. Constraints in the land and credit markets are likely explanations for these differences. In addition, all estimated models show that TE has a positive and significant association with education and extension.Central America, soil conservation, stochastic frontiers, switching regression, technical efficiency, Resource /Energy Economics and Policy,

Technical Efficiency and Adoption of Soil Conservation in El Salvador and Honduras

A household-level switching regression model is implemented to examine potential selectivity bias for rural households under high and low levels of investments in soil conservation in El Salvador and Honduras. In the presence of selectivity bias, separate stochastic production frontiers are estimated for low and high adopters. The main results indicate that households with higher levels of investments in soil conservation show higher average TE than those with a lower level of investments. Constrains in the rural land and credit markets are likely explanations for these differences. The results also indicate that for farms with lower levels of investments in soil conservation access to credit is a significant factor explaining the sources of inefficiency. Conversely, households with higher levels of investments have the highest partial output elasticity for land, the highest levels of TE and the smallest farms. These results are consistent with the presence of a failure in the land market which would limit access to land to the more efficient producers.Stochastic Frontiers, Technical Efficiency, Switching Regression, Central America, Soil Conservation, Land Economics/Use, d24, q12, o13, c21,

A measurement of the carbon sequestration potential of Guadua angustifolia in the Carrasco National Park, Bolivia

The carbon sequestration potential of an unmanaged and previously unstudied Guadua angustifolia bamboo forest in the Carrasco National Park of Bolivia has been studied, by estimating the total aboveground biomass contained in the forest. It was found that the aboveground biomass consisting of stems, branches, and foliage, contains a total of 200 tons per hectare, leading to an estimated 100 tons of carbon being stored per hectare aboveground, which is comparable to some species of tree such as the Chinese Fir; this bamboo species therefore has the potential to play a significant role in the mitigation of climate change. The relation between the biomass, M, of each component (stems, branches, and foliage) and the diameter, d, of the plant was also studied, by fitting allometric equations of the form M = αdβ. It was found that all components fit this power law relation very well (R2 > 0.7), particularly the stems (R2 > 0.8) and branches (R2 > 0.9) for which the relation is found to be almost linear

A Fuzzy Inference System for Closed-Loop Deep Brain Stimulation in Parkinson’s Disease

Parkinsons disease is a complex neurodegenerative disorder for which patients present many symptoms, tremor being the main one. In advanced stages of the disease, Deep Brain Stimulation is a generalized therapy which can significantly improve the motor symptoms. However despite its beneficial effects on treating the symptomatology, the technique can be improved. One of its main limitations is that the parameters are fixed, and the stimulation is provided uninterruptedly, not taking into account any fluctuation in the patients state. A closed-loop system which provides stimulation by demand would adjust the stimulation to the variations in the state of the patient, stimulating only when it is necessary. It would not only perform a more intelligent stimulation, capable of adapting to the changes in real time, but also extending the devices battery life, thereby avoiding surgical interventions. In this work we design a tool that learns to recognize the principal symptom of Parkinsons disease and particularly the tremor. The goal of the designed system is to detect the moments the patient is suffering from a tremor episode and consequently to decide whether stimulation is needed or not. For that, local field potentials were recorded in the subthalamic nucleus of ten Parkinsonian patients, who were diagnosed with tremor-dominant Parkinsons disease and who underwent surgery for the implantation of a neurostimulator. Electromyographic activity in the forearm was simultaneously recorded, and the relation between both signals was evaluated using two different synchronization measures. The results of evaluating the synchronization indexes on each moment represent the inputs to the designed system. Finally, a fuzzy inference system was applied with the goal of identifying tremor episodes. Results are favourable, reaching accuracies of higher 98.7 % in 70 % of the patients.Centro de Investigación Biomédica en RedDepto. de Psicología Experimental, Procesos Cognitivos y LogopediaDepto. de Radiología, Rehabilitación y FisioterapiaFac. de PsicologíaFac. de MedicinaTRUEpu

HERMES: Towards an Integrated Toolbox to Characterize Functional and Effective Brain Connectivity

The analysis of the interdependence between time series has become an important field of research in the last years, mainly as a result of advances in the characterization of dynamical systems from the signals they produce, the introduction of concepts such as generalized and phase synchronization and the application of information theory to time series analysis. In neurophysiology, different analytical tools stemming from these concepts have added to the ‘traditional’ set of linear methods, which includes the cross-correlation and the coherency function in the time and frequency domain, respectively, or more elaborated tools such as Granger Causality. This increase in the number of approaches to tackle the existence of functional (FC) or effective connectivity (EC) between two (or among many) neural networks, along with the mathematical complexity of the corresponding time series analysis tools, makes it desirable to arrange them into a unified-easy-to-use software package. The goal is to allow neuroscientists, neurophysiologists and researchers from related fields to easily access and make use of these analysis methods from a single integrated toolbox. Here we present HERMES (http://hermes.ctb.upm.es), a toolbox for the Matlab® environment (The Mathworks, Inc), which is designed to study functional and effective brain connectivity from neurophysiological data such as multivariate EEG and/or MEG records. It includes also visualization tools and statistical methods to address the problem of multiple comparisons. We believe that this toolbox will be very helpful to all the researchers working in the emerging field of brain connectivity analysis

Comparison of two modes of vitamin B12 supplementation on neuroconduction and cognitive function among older people living in Santiago, Chile: a cluster randomized controlled trial. a study protocol [ISRCTN 02694183]

BACKGROUND: Older people have a high risk of vitamin B12 deficiency; this can lead to varying degrees of cognitive and neurological impairment. CBL deficiency may present as macrocytic anemia, subacute combined degeneration of the spinal cord, or as neuropathy, but is often asymptomatic in older people. Less is known about subclinical vitamin B12 deficiency and concurrent neuroconduction and cognitive impairment. A Programme of Complementary Feeding for the Older Population (PACAM) in Chile delivers 2 complementary fortified foods that provide approximately 1.4 μg/day of vitamin B12 (2.4 μg/day elderly RDA). The aim of the present study is to assess whether supplementation with vitamin B12 will improve neuroconduction and cognitive function in older people who have biochemical evidence of vitamin B12 insufficiency in the absence of clinical deficiency. METHODS: We designed a cluster double-blind placebo-controlled trial involving community dwelling people aged 70-79 living in Santiago, Chile. We randomized 15 clusters (health centers) involving 300 people (20 per cluster). Each cluster will be randomly assigned to one of three arms: a) a 1 mg vitamin B12 pill taken daily and a routine PACAM food; b) a placebo pill and the milk-PACAM food fortified to provide 1 mg of vitamin B12; c) the routine PACAM food and a placebo pill.The study has been designed as an 18 month follow up period. The primary outcomes assessed at baseline, 4, 9 and 18 months will be: serum levels of vitamin B12, neuroconduction and cognitive function. CONCLUSIONS: In view of the high prevalence of vitamin B12 deficiency in later life, the present study has potential public health interest because since it will measure the impact of the existing program of complementary feeding as compared to two options that provide higher vitamin B12 intakes that might potentially may contribute in preserving neurophysiologic and cognitive function and thus improve quality of life for older people in Chile. TRIAL REGISTRATION: ISRCTN: ISRCTN02694183

Effect of a Nutrition Supplement and Physical Activity Program on Pneumonia and Walking Capacity in Chilean Older People: A Factorial Cluster Randomized Trial

Alan Dangour and colleagues report results from the CENEX (Cost-effectiveness Evaluation of a Nutritional supplement and EXercise program for older people) trial, which evaluates a nutritional and exercise program aiming to prevent pneumonia and physical decline in Chilean people

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016