Logarithmic periodicities in the bifurcations of type-I intermittent chaos

The critical relations for statistical properties on saddle-node bifurcations are shown to display undulating fine structure, in addition to their known smooth dependence on the control parameter. A piecewise linear map with the type-I intermittency is studied and a log-periodic dependence is numerically obtained for the average time between laminar events, the Lyapunov exponent and attractor moments. The origin of the oscillations is built in the natural probabilistic measure of the map and can be traced back to the existence of logarithmically distributed discrete values of the control parameter giving Markov partition. Reinjection and noise effect dependences are discussed and indications are given on how the oscillations are potentially applicable to complement predictions made with the usual critical exponents, taken from data in critical phenomena.Comment: 4 pages, 6 figures, accepted for publication in PRL (2004

GPS-based CERN-LNGS time link for Borexino

We describe the design, the equipment, and the calibration of a new GPS based time link between CERN and the Borexino experiment at the Gran Sasso Laboratory in Italy. This system has been installed and operated in Borexino since March 2012, and used for a precise measurement of CNGS muon neutrinos speed in May 2012. The result of the measurement will be reported in a different letter.Comment: 13 pages, 11 figure

Diversity of herbaceous forage species as sustainability indicator in Kenyan Rangeland.

Rangelands in Kenya make up for 70% of the land and hosts 60% of its livestock population. This ecosystem is largely inhabited by nomadic pastoralists whose livelihood depents on livestock. Land subdivision, population growth, climate change, devastating droughts, land degradation and unsustainable land use practices threaten the future of pastoralist and wildlife conservation in the rangelands. Knowledge about diversity of species is an important indicator of degraded land in the rangelands. Monitoring forage species can be a way to help livestock owning communities and farmers to recover degraded land and improve the natural environment. This study aimed to identify main herbaceous species present in nomadic pastoralist and farm rangelands in Kenya. This trial was conducted during the wet season in 2012. Two different environments were visited during a research expedition. Ol Maisor a commercial ranch that has been utilizing Holistic Management for the past years is located in Laikipia County. The second one being in Merti, Isiolo County composed of four sites: Bisan Biliquo, Bulesa, Korbesa and Malkagalla and being managed by the Merti Grazing Committee, a nomadic pastoralist community. Five randomly selected sites were visited in Ol Maisor and twelve sites in Merti. All sites were identified by GPS and their coordinates recorded. In each site, plants were collected to make exsiccates using traditional techniques (by press). Botanic characterization was done by identification of family, genus and species at the Herbarium of the Kenya Agricultural Research Institute (KARI) in Kiboko. At Ol Maisor Ranch the dominant family found was Poaceae (grasses). This family represents the most important species for grazing lands in Kenya indicating good and healthy rangelands. It was possible to identify 51 different grass species at Ol Maisor Ranch. At least, 13 genera were identified at least seven to eight times in this location: Aristida, Bothrichloa, Cenchrus, Cynodon, Digitaria, Eragrostis, Harpchne, Panicum, Paspalum, Pennisetum, Setaria, Themeda, Trachypogon. Eragrostis tenuiflora was the most abundant species. This grass is a poor constituent of pasture once livestock prefers other more palatable species when it is available. In Merti, forb were identified as more than 50% of the botanic pasture composition. The total number of species found were 67. At least ten different botanic families were present in this region: Acanthaceae, Amaranthaceae, Combretaceae, Fabaceae, Labiatae, Liliaceae, Malvaceae, Onagraceae, Poaceae, Polygonaceae and Sollanaceae. It was possible to identify 11 genera of grasses: Aristida, Cenchrus, Chloris, Cyprus, Digitaria, Eleusine, Eragrostis, Hyperenia, Panicum, Sehima, Tetrapogon. The most frequent genus was Eragrostis. Among the forb only three genera were important: Sida, Barelia and Ocimum. Two of these can be used as indicator of degraded lands and they were present in large areas. In Merti the observed biodiversity shows a potential for various livestock species other than cattle such as sheep, goats and other ruminants to use the land for grazing, Ol Maisor?s rangeland is more appropriate for cattle grazing, but it is necessary to monitor some of the less palatable species found in large density and the possibility to substitute it with better grass species. In both places a good biodiversity could be identified, however, it is necessary to carry out annual monitoring in order to keep weeds under control in the Kenyan rangelands

Evaluation degree of degraded rangeland on grazing communities in Kenya.

Most of 80% of Kenya´s land is categorized as arid and semi-arid. Agropastoralism and pastoralism based on livestock production serve as the bedrock of site livelihoods and culture. Pastoralists? livelihoods are affected by frequent and severe droughts, growing demographic pressure and conflicts over natural resource utilization. Vulnerability worsened by accessible grazing lands is often mismanaged and either overgrazed or underutilized leading to land degradation. This work aimed to develop a score index to classify degraded land degree to help technician and pastoralist in adequate use of tools to recovery degraded lands. This trial was conducted using participatory research with four grazing communities (Bisan Biliquo, Bulesa, Korbesa and Malkagalla) in Kenyan dry land from May 2011 to November 2012. There were characterized three sites in each community. First of all, a general characterization was made. In this first characterization were collected information about soil, plant, land use, water source distance and wildlife. Based on this information was chosen spots to make monitoring rangeland on each site. Transect method was used to collect information about bare ground (%), plant cover(%), plant height(cm), number of species(unit), biomass(kg) and litter (kg) production. A practical sheet from Mpala Institute was used to collect data on field. These five parameters were chosen because it was easier to collect by technician and pastoralist. Each parameter was classified in categories according type of measure (%, kg or cm) and could be analyzed and received a grade between 0 and 5. From summing the grades a score index was created to classify stage of degraded land. Five categories were made: 1-6 grades meant high degraded land; 7-12 degraded rangeland; 13-18 recovery rangeland; 19-24 good rangeland and 25-30 healthy rangeland. None of the sites got good or healthy rangeland. In fact all these areas are included in a program to recovering degraded land. The best situation was found in Bulesa where most of areas were classified as recovery land. In this case was recommended to reduce grazing pressure in order to improve litter production. Korbesa place second and was classified as recovery land. It was recommended basically management adjustment for improve biomass production. Bisan Biliquo areas were classified as high or degraded and needed some interventions on management level. In one spot and reseeding was recommended in the two others. Malkagalla was the worse scored site and presented the worse condition rangeland. All spots monitored were classified as high degraded land. Management intervention in this place should be directed to recover biodiversity by reseeding native species and improve biomass production Based on this was highly recommended exclude animal grazing during a period of time. Tools to monitoring rangeland and support diagnostic for degraded lands can be useful to identify problems and propose solutions to recovery degraded lands in dry rangelands

Galactic or extragalactic chemical tagging for NGC 3201?: Discovery of an anomalous CN-CH relation

The origin of the globular cluster (GC) NGC 3201 is under debate. Its retrograde orbit points to an extragalactic origin, but no further chemical evidence supports this idea. Light-element chemical abundances are useful to tag GCs and can be used to shed light on this discussion. Aims. Recently it was shown that the CN and CH indices are useful to identify GCs that are anomalous to those typically found in the Milky Way. A possible origin of anomalous clusters is the merger of two GCs and/or the nucleus of a dwarf galaxy. We aim to derive CN and CH band strengths for red giant stars in NGC3201 and compare these with photometric indices and high-resolution spectroscopy and discuss in the context of GC chemical tagging. Methods. We measure molecular band indices of S(3839) and G4300 for CN and CH, respectively from low-resolution spectra of red giant stars. Gravity and temperature effects are removed. Photometric indices are used to indicate further chemical information on C+N+O or s-process element abundances that are not derived from low-resolution spectra. Results. We found three groups in the CN-CH distribution. A main sequence (S1), a secondary less-populated sequence (S2), and a group of peculiar (pec) CN-weak and CH-weak stars, one of which was previously known. The three groups seem to have different C+N+O and/or s-process element abundances, to be confirmed by high-resolution spectroscopy. These are typical characteristics of anomalous GCs. The CN distribution of NGC 3201 is quadrimodal, which is more common in anomalous clusters. However, NGC 3201 does not belong to the trend of anomalous GCs in the mass-size relation. Conclusions. The globular cluster NGC 3201 shows signs that it can be chemically tagged as anomalous: it has an unusual CN-CH relation, indications that pec-S1-S2 is an increasing sequence of C+N+O or s-process element abundances, and a multi-modal CN distribution that seems to correlate with s-process element abundances. The non-anomalous characteristics are that it has a debatable Fe-spread and it does not follow the trend of mass size of all anomalous clusters. Three scenarios are postulated here: (i) if the sequence pec-S1-S2 has increasing C+N+O and s-process element abundances, NGC 3201 would be the first anomalous GC outside of the mass-size relation; (ii) if the abundances are almost constant, NGC 3201 would be the first non-anomalous GC with multiple CN-CH anti-correlation groups; or (iii) it would be the first anomalous GC without variations in C+N+O and s-process element abundances. In all cases, the definition of anomalous clusters and the scenario in which they have an extragalactic origin must be revised.Fil: Dias, B.. European Southern Observatory Chile.; ChileFil: Araya, I.. Universidad de Valparaiso; ChileFil: Nogueira-Cavalcante, J. P.. Observatorio Do Valongo; Brasil. Universidade Federal do Rio de Janeiro; BrasilFil: Saker, Leila Yamila. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Shokry, A.. European Southern Observatory Chile.; Chil

Evolution of magnetic fields through cosmological perturbation theory

The origin of galactic and extra-galactic magnetic fields is an unsolved problem in modern cosmology. A possible scenario comes from the idea of these fields emerged from a small field, a seed, which was produced in the early universe (phase transitions, inflation, ...) and it evolves in time. Cosmological perturbation theory offers a natural way to study the evolution of primordial magnetic fields. The dynamics for this field in the cosmological context is described by a cosmic dynamo like equation, through the dynamo term. In this paper we get the perturbed Maxwell's equations and compute the energy momentum tensor to second order in perturbation theory in terms of gauge invariant quantities. Two possible scenarios are discussed, first we consider a FLRW background without magnetic field and we study the perturbation theory introducing the magnetic field as a perturbation. The second scenario, we consider a magnetized FLRW and build up the perturbation theory from this background. We compare the cosmological dynamo like equation in both scenarios

Uma análise econômica e benefícios ambientais decorrentes da adoção de tecnologias em pastagens melhoradas no Acre.

O objetivo deste artigo foi de avaliar os resultados econômicos dos sistemas de produção tradicional, melhorado e avançado da pecuária de corte no Acre e os benefícios ambientais decorrentes da adoção de tecnologias em pastagens melhoradas. Esta avaliação é relevante, uma vez que demonstra a necessidade de uma reestruturação do sistema produtivo da pecuária de corte no Estado. Os dados utilizados na análise foram obtidos pelo método de painel técnico, que consiste em selecionar e reunir um grupo de produtores e técnicos com grande conhecimento no assunto. Na reunião técnica foi caracterizado detalhadamente o sistema modal e seus coeficientes técnicos de produção. A partir do sistema modal delinearam-se os sistemas de produção melhorados e avançados, com incorporação de inovações tecnológicas já testadas e adotadas por pequeno número de produtores. As conseqüências da utilização das tecnologias são observadas no aumento da capacidade suporte das pastagens nos níveis tecnológico melhorado e avançado em 50% e 150%, respectivamente, quando comparado com o sistema tradicional. Conclui-se que o maior nível tecnológico utilizado nos sistemas melhorado e avançado confere impactos econômicos e ambientais positivos, tornando estes sistemas de produção economicamente mais viáveis e ecologicamente mais sustentáveis

Grass and forage research indexed by the Web of Science from 2005 to 2015.

Beef and milk production in Brazil is mainly pasture-based (Assis et al., 2005; ABIEC, 2018; FERRAZ; FELÍCIO, 2010). There is around 160 million ha of pasturelands in Brazil, which represents 45% of the agricultural area (IBGE, 2017). Sown pastures represent around 70% of the total pasture areas and are located mainly in the North, Southeast and Center-West regions of Brazil (IBGE, 2018). Grass and forage research in Brazil has shifted focus along the years. Traditionally, grass and forage research focused mostly on topics related to forage and animal production. Currently, besides the search for increasing production to fulfill a growing worldwide animal protein demand, grass and forage research faces new challenges like land degradation, climate change, competing land use, environmental impacts, including natural resources utilization, deforestation, loss of biodiversity, fragmentation, and loss of habitats, reduction on ?labor force? in rural areas, sustainability, among others. Indicators on science and technology reflect the central tendencies on scientific, technological and innovative activities from a country, institution or knowledge area. The development of specific indicators on science and technology on grass and forage science may be helpful for planning and evaluating activities of research groups and policy-makers alike. Based on specific indicators on science and technology it is possible to identify the main topics and grass and forage science research groups, and also verify if their activity is related to the main problems from the pasturebased animal production sector. This information may contribute to the more efficient use of research resources and to the progress of scientific advance on pasture-based animal production sustainability and competitiveness