Photohadronic scenario in interpreting the February-March 2014 flare of 1ES 1011+496

The extraordinary multi-TeV flare from 1ES 1011 +496 during February-March 2014 was observed by MAGIC telescopes for 17 nights and the average spectrum of the whole period has a non-trivial shape. We have used the photohadronic model and a template EBL model to explain the average spectrum which fits well to the flare data. The spectral index $\alpha$ is the only free parameter in our model. We have also shown that the non-trivial nature of the spectrum is due to the change in the behavior of the optical depth above $\sim 600$ GeV $\gamma$-ray energy accompanied with the high SSC flux.Comment: 11 pages, 3 figures, LaTe

Blazar origin of some IceCube events

Recently ANTARES collaboration presented a time dependent analysis to a selected number of flaring blazars to look for upward going muon events produced from the charge current interaction of the muon neutrinos. We use the same list of flaring blazars to look for possible positional correlation with the IceCube neutrino events. In the context of photohadronic model we propose that the neutrinos are produced within the nuclear region of the blazar where Fermi accelerated high energy protons interact with the background synchrotron/SSC photons. Although we found that some objects from the ANTARES list are within the error circles of few IceCube events, the statistical analysis shows that none of these sources have a significant correlation.Comment: Latex file, 6 pages, two columns, 1 Figur

O não-poder do papa em Guilherme de Ockham

Os escritos políticos de Ockham giram ao redor da pergunta a respeito do poder do papa. Como esse poder foi concedido por Cristo, deve-se consultar a Sagrada Escritura para saber o que ela diz a respeito. Mas a exegese bíblica cabe aos teólogos e não aos juristas. Na qualidade de teólogo Ockham afirma que os poderes do papa situam-se na ordem espiritual e mesmo nessa ordem ele não é ilimitado, pois se atém ao que foi concedido expressamente por Cristo e deve respeitar a liberdade dos fiéi

Interactome Data and Databases: Different Types of Protein Interaction

In recent years, the biomolecular sciences have been driven forward by overwhelming advances in new biotechnological high-throughput experimental methods and bioinformatic genome-wide computational methods. Such breakthroughs are producing huge amounts of new data that need to be carefully analysed to obtain correct and useful scientific knowledge. One of the fields where this advance has become more intense is the study of the network of ‘protein–protein interactions’, i.e. the ‘interactome’. In this short review we comment on the main data and databases produced in this field in last 5 years. We also present a rationalized scheme of biological definitions that will be useful for a better understanding and interpretation of ‘what a protein–protein interaction is’ and ‘which types of protein–protein interactions are found in a living cell’. Finally, we comment on some assignments of interactome data to defined types of protein interaction and we present a new bioinformatic tool called APIN (Agile Protein Interaction Network browser), which is in development and will be applied to browsing protein interaction databases

Static Analysis of Usefulness States in Transition P systems

Transition P Systems are a parallel and distributed computational model based on the notion of the cellular membrane structure. Each membrane determines a region that encloses a multiset of objects and evolution rules. Transition P Systems evolve through transitions between two consecutive configurations that are determined by the membrane structure and multisets present inside membranes. Moreover, transitions between two consecutive configurations are provided by an exhaustive non-deterministic and parallel application of evolution rules. But, to establish the rules to be applied, it is required the previous calculation of useful, applicable and active rules. Hence, computation of useful evolution rules is critical for the whole evolution process efficiency, because it is performed in parallel inside each membrane in every evolution step. This work defines usefulness states through an exhaustive analysis of the P system for every membrane and for every possible configuration of the membrane structure during the computation. Moreover, this analysis can be done in a static way; therefore membranes only have to check their usefulness states to obtain their set of useful rules during execution

Preliminary results of an algorithm for customized soft contact lens ablation

OBJETIVO: Desenvolver simulação computadorizada de ablação para produzir lentes de contato personalizadas a fim de corrigir aberrações de alta ordem. MÉTODOS: Usando dados reais de um paciente com ceratocone, mensurados em um aberrômetro ("wavefront") com sensor Hartmann-Shack, foram determinados as espessuras de lentes de contato que compensam essas aberrações assim como os números de pulsos necessários para fazer ablação as lentes especificamente para este paciente. RESULTADOS: Os mapas de correção são apresentados e os números dos pulsos foram calculados, usando feixes com a largura de 0,5 mm e profundidade de ablação de 0,3 µm. CONCLUSÕES: Os resultados simulados foram promissores, mas ainda precisam ser aprimorados para que o sistema de ablação "real" possa alcançar a precisão desejada.PURPOSE: To develop a computer simulation for customized soft contact lenses in order to correct aberrations of higher order. METHODS: Using real data from a patient diagnosed with keratoconus, which were measured using a Hartmann-Shack wavefront sensor, the thickness of the contact lenses that compensate these aberrations as well the numbers of pulses required to ablate the lenses were specifically determined for the patient. RESULTS: The maps of correction are presented and the numbers of pulses are calculated, using a 0.5 mm beam width and a 0.3 µm ablation depth. CONCLUSIONS: The results shown here are promising, but they should be improved so that the ablation in actual physical systems can reach the desired accuracy

Three Essays on Evaluating the Impact of Natural Resource Management Programs

This dissertation is composed of three papers describing the nexus between natural resource management programs, farmer well-being, and productivity. Our study sheds light on the effectiveness of actions that have been or could be implemented to address the “triangle of poverty.” This triangle connects low farm productivity to high poverty, which forces farmers to increase the pressure on natural resources thus further degrading the environment and resulting in even lower productivity and more poverty. Natural resource management (NRM) imbeds key agricultural policies, which aim at handling resource degradation while enhancing productivity particularly among smallholder farmers. Technologies promoted through the use of NRM programs encompass conservation agriculture, water and integrated pest management, agroforestry, and silvopastoral activities. Although most of these technologies have been promoted since the early 1960s, it was not until 1989 when the CGIAR emphasized the value of NRM technologies as tools to ensure the sustainability of agricultural systems. Since then, the implementation of NRM programs have evolved around the following definition: “Sustainable agriculture should involve the successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of the environment and conserving natural resources (Consultative Group on International Agricultural Research [CGIAR] 2006, p.4).” In general, these programs aim at developing and disseminating technologies, which improve the quality of soil and water, diversify the agro-ecosystem and build farm capacity to mitigate the effects of climate change. To examine to what extent NRM programs have achieved their aim, in the first essay, meta-regression analysis is used to explore the effect that natural resource management (NRM) programs have on monetary outcomes and on productivity. In doing so, we use a comprehensive dataset of 75 impact evaluation studies and 215 observations from all over the world (equivalent to a sample of 31,991 treated and 42,936 control farmers) to explain why impact varies among studies and across different interventions, regions, and methods. Econometric results from ordered probit, probit, OLS regression, and Bayesian regression models consistently show that NRM programs have a significant positive effect on the monetary outcomes and productivity of beneficiaries relative to control farmers. Overall, NRM technologies increase monetary outcomes on average by 8%, and yields by 13%. Furthermore, the impacts of NRM programs could be larger if: i) participatory methods to transfer the technology to the final user are incorporated in the design; ii) appropriate training to boost the adoption of the technology is provided; iii) NRM technologies are tailored to the rainfall patterns of the intervention area; iv) government units are more efficient in the delivery of technologies; and v) the evaluation of NRM programs account for the time necessary for these programs to produce results. The first essay compiles evidence from a large number of published analyses. We complement this evidence in the following two essays with original empirical analyses of a specific NRM intervention, the Socio-Environmental and Forestry Development Program-II (POSAF-II), which was implemented by the Nicaraguan Ministry of the Environment and Natural Resources (MARENA). The goal was to promote economic development and environmental sustainability. POSAF-II financed a total of 13,477 farmers occupying 69,767 hectares in several major river basins that were severely damaged by Hurricane Mitch in 1998. Therefore, this program represents a unique opportunity to evaluate the economic impact of NRM programs in an area affected by a massive weather event, characterized by high soil degradation and poverty. The second essay is an analysis of the economic impact of natural resource technologies delivered by POSAF-II. We use cross-sectional data for 1,483 households, from 212 treated and control communities. Results obtained through propensity score matching (PSM), ordinary least squares (OLS), weighted least squares regression (WLS) based on PSM, and instrumental variables (IV) regression indicate that POSAF-II has had a positive impact on the total value of agricultural production of beneficiary farmers relative to appropriate control groups. The estimated internal rate of return supports the hypothesis that increasing household income while encouraging the sustainable use of natural resources through the implementation of suitable management programs can be complementary development objectives. The third essay examines the impact of POSAF-II on two critical components of productivity: technological change (TC) and technical efficiency (TE). We use propensity score matching (PSM) to mitigate potential biases from observable variables along with a recently introduced stochastic production frontier (SPF) model that addresses sample selection bias arising from unobservable variables. Our results show that POSAF-II has had a positive impact on both TC and TE. This essay contributes to the literature on impact evaluation by showing how an intervention designed to improve natural resource management can also enhance the income of poor farm households through increases in productivity

Electrochemical determination of the antioxidant capacity of industrialized fruits juices using the CRAC assay

Fruits juices are natural sources of several compounds that present antioxidant action. Together with the fruits, they contribute with almost 40% of the antioxidant capacity in a healthy diet avoiding and preventing diseases deriving from oxidative stress. The present study determined the antioxidant capacity of seven samples of industrialized fruits juices applying CRAC (Ceric Reducing/Antioxidant Capacity) assay, a new electrochemistry assay that evaluates, by means of chronoamperometric measurements, the ability of a sample in reducing species Ce4+ in acid media. At the end of the assay was obtained the following classification: cashew > guava > grape > mango > apple > orange > passion fruit

A bracket for filming nests

Els patrons d'alimentació dels progenitors i la interacció entre els polls és de gran importància en qualsevol estudi sobre les relacions paternofilials en ocells altricials. La gravació de seqüències de vídeo ofereix una eina fonamental per a l'anàlisi d'aquests comportaments. En aquest article es descriu un suport per subjectar una càmera de video, emprada amb èxit en un estudi amb la garsa blava. El suport no va afectar negativament als ocells, ja que no es van detectar diferències en el desenvolupament dels polls ni en les taxes de predació entre els nius en els quals es va utilitzar el suport i aquells altres en els quals no es va emprar

Scale-invariance underlying the logistic equation and its social applications

On the basis of dynamical principles we i) advance a derivation of the Logistic Equation (LE), widely employed (among multiple applications) in the simulation of population growth, and ii) demonstrate that scale-invariance and a mean-value constraint are sufficient and necessary conditions for obtaining it. We also generalize the LE to multi-component systems and show that the above dynamical mechanisms underlie a large number of scale-free processes. Examples are presented regarding city-populations, diffusion in complex networks, and popularity of technological products, all of them obeying the multi-component logistic equation in an either stochastic or deterministic way.Instituto de Física La PlataConsejo Nacional de Investigaciones Científicas y Técnica