An investigation into hybrid power trains for vehicles with regenerative braking

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Maximum Palinstrophy Growth in 2D Incompressible Flows

In this study we investigate vortex structures which lead to the maximum possible growth of palinstrophy in two-dimensional incompressible flows on a periodic domain. The issue of palinstrophy growth is related to a broader research program focusing on extreme amplification of vorticity-related quantities which may signal singularity formation in different flow models. Such extreme vortex flows are found systematically via numerical solution of suitable variational optimization problems. We identify several families of maximizing solutions parameterized by their palinstrophy, palinstrophy and energy and palinstrophy and enstrophy. Evidence is shown that some of these families saturate estimates for the instantaneous rate of growth of palinstrophy obtained using rigorous methods of mathematical analysis, thereby demonstrating that this analysis is in fact sharp. In the limit of small palinstrophies the optimal vortex structures are found analytically, whereas for large palinstrophies they exhibit a self-similar multipolar structure. It is also shown that the time evolution obtained using the instantaneously optimal states with fixed energy and palinstrophy as the initial data saturates the upper bound for the maximum growth of palinstrophy in finite time. Possible implications of this finding for the questions concerning extreme behavior of flows are discussed.Comment: 33 pages, 8 figures; to appear in "Journal of Fluid Mechanics

Social and environmental impacts of free port and mass tourism models on a small island : the case of San Andrés, Colombia

Tourism-driven development economic models have shaped the Caribbean region since the 1950s, generating major transformations as a result of the implementation of neo-liberal approaches to the territories. The archipelago of San Andrés, Providencia y Santa Catalina, has not been an exception to these phenomena. In particular, San Andrés Island has experienced a process of Colombianization, imposed economic development models, and population growth with serious implications for the local communities and the environment. This study investigated how the free port and mass tourism models for economic development have influenced the socio-economic realities of the island’s inhabitants and impacted the environmental conditions of San Andrés. 63 semi-structured interviews and extensive field observations were conducted. The study explored concepts of overpopulation and resource scarcity, neo-liberalism, neo-colonialism, land grabbing, and marginalization to illuminate the different roles of tourism and resident communities in relation to urbanization, infrastructure systems, population growth, and changes in landscape and land tenure. Large-scale changes have occurred in San Andrés in the last 60 years as a result of the implementation of the free port and mass tourism models. Major infrastructure projects, extensive urbanization and tourism infrastructure, and migration-driven population growth have caused substantial environmental degradation across the island. Events of land grabbing and displacements, unequal opportunities of access to drinking water, in combination with unsustainable tourism practices which generate significant pressure on the island’s resources and ecosystems and trigger conflicts with local inhabitants, have determined the marginalization of part of the Raizal and Continental societies. The economic dependence on tourism portrays a scenario of increasing vulnerability for excluded islanders that have abandoned traditional livelihoods to seek for a better future by joining tourism activities, becoming entirely dependent on the ever-growing tourism. The Colombianization of San Andrés, the free port and the mass tourism model are clear examples of neo-colonial approaches to a territory that shift the power from the local level to transfer it to external, more powerful actors. In an island that depends on the revenues generated by tourism, the uncertainty of the future due to climate change and global processes, require new forms of tourism, territorial planning, and diversification of livelihoods, which should give local communities of San Andrés adequate frameworks and tools to face future changes.M-IE

Effects of Wilting Extent on the Phytoestrogen Levels, Nutritional Value, Microbial Populations, and In Vitro Ruminal Methane Emissions of Red Clover Hay and Silage Across Stages

The main objective of this thesis is to improve the understanding and awareness of methodologies to decrease phytoestrogens in conserved legumes without sacrificing forage nutritive value. In chapter 1, we discussed the main factors influencing each stage of hay production and our current understanding of the hay microbiome dynamics. The primary objective of haymaking is to dry forage enough (80-85% DM) to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of DM losses. This chapter discusses these factors and the strategies that have been developed to mitigate these nutrient losses. A major emphasis was placed on hay microbiota dynamics, as it has been scarcely studied despite its importance on nutrient losses during storage and harvest, especially in high moisture conditions. Since soil particles are a significant source of undesirable microbes and ash contamination, the effects of cutting height, mower type, and swath manipulation on soil contamination were discussed. Also, the impact of environmental conditions and swath manipulation on wilting time was analyzed for both humid and arid conditions. Special attention was given to design improvements in harvesting equipment to reduce curing time and field losses. Furthermore, we assessed the nutrient losses during storage caused by undesirable microbial and residual plant enzymatic activity resulting from excessive moisture at baling or re-introduced moisture during storage. The extent of spoilage during storage depends not only on bale moisture but also on bale size, density, shape, wrapping, forage type, and storage facilities. A Venn diagram analysis condensed all relevant hay microbiology research and showed that each phase of the haymaking process has a unique microbiome. It also showed that certain fungal and bacterial genera could be shared across more than one hay production phase. For instance, Aspergillus, Cladosporium, and Alternaria are fungal genera that tend to be present throughout the haymaking process. In order to take corrective actions, hay producers need to be aware of the increased susceptibility to nutrient losses associated with particular field and storage practices, environmental conditions, and forage types. In Chapter 2, we evaluated the effects of insufficient (WET) or ample (CUR) wilting on the phytoestrogen levels, nutritional value, microbial populations, in vitro ruminal methane emissions, and in situ degradability of red clover silage (29.4 and 45.3% DM) and hay (65.1 and 89.1, respectively) across the storage stages. Measurements were taken at the start of storage (STRT), after 14 d (MicA), and once storage processes had stabilized for hay and silage (50 and 78 d, respectively; LATE). Only LATE samples of hay and silage were tested for the in situ procedure. Data were analyzed as a RCBD (5 blocks) with a 2 (wilting extents) x 2 (conservation methods) x 3 (storage stages) factorial. Results showed that storage DM losses were higher for WET hay than CUR but no differences were observed between WET and CUR silage. Ample wilting of hay and silage preserved better water-soluble carbohydrates during storage relative to insufficient wilting. Due to microbial spoilage, the NH3-N of WET hay was higher than CUR hay after 14 d of storage, but the opposite was observed after 50 d. For the WET and CUR silage, NH3-N increased across the ensiling period. The neutral detergent fiber of WET hay increased across storage stages while it remained stable for CUR hay. In contrast, the neutral detergent fiber of WET and CUR silage decreased during the ensiling period. The WET hay favored the growth of molds during storage, while CUR hay reduced their counts after 50 d of storage. For silage, mold counts were lower in WET compared to CUR after 14 d of storage but no differences were observed after 78 d. When the ensiling period is limited to 14 d, CUR silage that was aerobically exposed for 7 d was more susceptible to storage DM losses and subsequent heating relative to WET. However, if the ensiling period is extended to 78 d, no differences were observed between WET and CUR silage in terms of HDD and storage DM losses after being aerobically challenged. Ample wilting preserved the optimal ruminal fermentation kinetics of hay compared to insufficient wilting, while the ruminal fermentation kinetics of silage was not affected by the wilting extent. In vitro ruminal fermentation of WET silage resulted in higher methane yield than CUR, whereas methane yield of WET and CUR hay were not different. For both conservation methods, insufficient wilting reduced methane yield only at the end of storage. The in situ rumen degradability kinetics showed that ensiling increased the soluble DM fraction relative to haymaking. Ensiling reduced the potentially degradable DM fraction compared to haymaking but increased the rate of degradation of DM. Within insufficient wilting, silage had a higher degradation rate of NDF than hay. Ample wilting was more beneficial for silage than hay in terms of decreasing the levels of phytoestrogens. Across storage stages, hay had lower formononetin and biochanin A than silage. Formononetin and biochanin A of red clover hay decreased after 14 d of storage due to microbial degradation. Overall, ample wilting helped conserve the nutritional quality of hay and silage and decreased the phytoestrogens, especially in silage

Pensamiento algebraico: contraste entre resoluciones de distintos niveles académicos, una tarea de generalización de patrones

El estudio aborda el análisis de la aplicación de una actividad sobre generalización de patrones realizada a dos estudiantes de diferentes niveles académicos, en la cual un estudiante no ha tenido ningún acercamiento al álgebra escolar y el otro pertenece a la Licenciatura en Educación Básica con Énfasis en Matemáticas (LEBEM), con el objetivo de reconocer que aspectos del pensamiento algebraico emergen en la resolución de dicha actividad y además, contrastar los diferentes resultados obtenidos en ambos casos, en términos de abordaje de la tarea y solución a ella, encontrando que al comprender el álgebra desde lo puramente simbólico se pueden generar obstáculos en el desarrollo de este tipo de actividades, dado que el pensamiento de alguna manera se condiciona a buscar una expresión netamente literal

Using improved Operator Product Expansion in Borel-Laplace Sum Rules with ALEPH τ\tau decay data, and determination of pQCD coupling

We use improved truncated Operator Product Expansion (OPE) for the Adler function, involving two types of terms with dimension $D=6$, in the double-pinched Borel-Laplace Sum Rules and Finite Energy Sum Rules for the V+A channel strangeless semihadronic $\tau$ decays. The generation of the higher order perturbative QCD terms of the $D=0$ part of the Adler function is carried out using a renormalon-motivated ansatz incorporating the leading UV renormalon and the first two leading IR renormalons. The trunacted $D=0$ part of the Sum Rules is evaluated by two variants of the fixed-order perturbation theory (FO), by Principal Value of the Borel resummation (PV), and by contour-improved perturbation theory (CI). For the experimental V+A channel spectral function we use the ALEPH $\tau$-decay data. We point out that the truncated FO and PV evaluation methods account correctly for the renormalon structure of the Sum Rules, while this is not the case for the truncated CI evaluation. We extract the value of the ${\overline {\rm MS}}$ coupling $\alpha_s(m_{\tau}^2) = 0.3235^{+0.0138}_{-0.0126}$ [$\alpha_s(M_Z^2)=0.1191 \pm 0.0016$] for the average of the two FO methods and the PV method, which we consider as our main result. If we included in the average also CI extraction, the value would be $\alpha_s(m_{\tau}^2) = 0.3299^{+0.0232}_{-0.0225}$ [$\alpha_s(M_Z^2)=0.1199^{+0.0026}_{-0.0028}$]. This work is an extension and improvement of our previous work [Eur.Phys.J.C81 (2021) 10, 930] where we used for the truncated OPE a more naive (and widely used) form and where the extracted values for $\alpha_s(M_Z^2)$ were somewhat lower.Comment: v3: 20 pages, 6 figures; corrected list of reference

Adaptation through chromosomal inversions in Anopheles

Chromosomal inversions have been repeatedly involved in local adaptation in a large number of animals and plants. The ecological and behavioral plasticity of Anopheles species—human malaria vectors—is mirrored by high amounts of polymorphic inversions. The adaptive significance of chromosomal inversions has been consistently attested by strong and significant correlations between their frequencies and a number of phenotypic traits. Here, we provide an extensive literature review of the different adaptive traits associated with chromosomal inversions in the genus Anopheles. Traits having important consequences for the success of present and future vector control measures, such as insecticide resistance and behavioral changes, are discussed.Anna Ullastres is an FPI fellow (BES-2012-052999) and Josefa González is a Ramón y Cajal fellow (RYC-2010-07306). This work was supported with startup funds from IRD-MIVEGEC awarded to Diego Ayala, and with grants from the European Commission (Marie Curie CIG PCIG-GA-2011-293860) and the Spanish Government (Fundamental Research Projects Grant BFU-2011-24397) awarded to Josefa González.Peer reviewe

Advances and Perspectives in the Study of the Malaria Mosquito Anopheles funestus

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