4,241 research outputs found
Critical Steps of Plasmodium falciparum Ookinete Maturation
The egress and fertilization of Plasmodium gametes and development of a motile ookinete are the first crucial steps that mediate the successful transmission of the malaria parasites from humans to the Anopheles vector. However, limited information exists about the cell biology and regulation of this process. Technical impediments in the establishment of in vitro conditions for ookinete maturation in Plasmodium falciparum and other human malaria parasites further constrain a detailed characterization of ookinete maturation. Here, using fluorescence microscopy and immunolabeling, we compared P. falciparum ookinete maturation in Anopheles coluzzii mosquitoes in vivo and in cell culture in vitro. Our results identified two critical steps in ookinete maturation that are regulated by distinct mosquito factors, thereby highlighting the role of the mosquito environment in the transmission efficiency of malaria parasites
Asymptotic approach to Special Relativity compatible with a relativistic principle
We propose a general framework to describe Planckian deviations from Special
Relativity (SR) compatible with a relativistic principle. They are introduced
as the leading corrections in an asymptotic approach to SR going beyond the
energy power expansion of effective field theories. We discuss the conditions
in which these Planckian effects might be experimentally observable in the near
future, together with the non-trivial limits of applicability of this
asymptotic approach that such a situation would produce, both at the very high
(ultraviolet) and the very low (infrared) energy regimes.Comment: 12 page
Private land conservation policies: navigating from global gaps to local perceptions and needs.
Despite efforts to reverse the current global environmental crisis that threatens biodiversity and human well-being, many indicators suggest we are still far from changing the main trajectory towards sustainability. With privately owned land covering large areas of the world, private land conservation (PLC) has been recognized as a promising strategy to complement protected area networks in meeting biodiversity conservation objectives. However, the overall success of PLC depends on designing and implementing a suite of policies according to geographical contexts and to the needs, values, and capabilities of different stakeholders. In my doctoral thesis, I aim to identify challenges and opportunities to foster PLC at different geographical scales by understanding the main trends and gaps in a global PLC literature review and by assessing landowners’ preferences and needs at national and local levels. In order to do so I followed transdisciplinary approaches, combining theories and methods from the natural and social sciences in collaboration with stakeholders outside academia.
In the first chapter, I carried out an in-depth global literature review of PLC scientific articles. My results revealed that most studies have focused on limited geographical contexts and policies. This highlighted the need for i) assessing a more diverse set of policy instruments to increase participation; ii) increasing stakeholders’ engagement in research to better inform PLC policymaking; iii) better understanding barriers and opportunities to foster PLC in underrepresented regions, such as South America.
Based on findings from my first chapter, I conducted two empirical studies at local and national levels in Uruguay, a country where most of the land is privately owned (~96%). While the importance of voluntary PLC has been recognized by law in 2017, in Uruguay PLC policy has not been developed or implemented yet. Hence, there is a need to understand context-specific landowners’ preferences for voluntary PLC to inform policy-making at early stages.
In the second chapter, I applied qualitative methods to explore landowners´ perceptions, motivations and needs for voluntary conservation in a cultural landscape in north-eastern Uruguay. I found that landowners considered themselves and their neighbours as local environmental stewards and their main needs to support biodiversity conservation were mostly related to enhance land management and social cohesion. My results revealed that strengthening existing links between people and nature and addressing local rural development needs could confer both social and conservation benefits in a just and sustainable way.
In the third chapter, I used stated preference methods to assess landowners’ preferences for hypothetical voluntary PLC policies at the national level in Uruguay. My results revealed that landowners had high willingness to engage in voluntary conservation initiatives if future policies would meet their heterogeneous preferences. Offering a diverse set of policy instruments, mainly non-monetary incentives, while fostering networks and collaboration with different stakeholders could help increase participation and long-term engagement in voluntary PLC.
To conclude, by following a transdisciplinary approach my thesis contributes to identifying and addressing research gaps in PLC at different scales with practical implications for biodiversity conservation, sustainability, and policymaking in Uruguay and elsewhere in the world in similar contexts. In addition, my thesis highlights the need for future research to disentangle the main contextdependent dimensions driving PLC effectiveness but also to identify general principles that could inform the design, governance and implementation of legitimate and equitable policies across contexts.Agencia Nacional de Investigación e InnovaciónDissertation completion grant (2020) University of Helsink
La construcción de mundos imaginarios: la obra de Alfred Kubin
Recoge los trabajos presentados en el II Congreso sobre arte, literatura y cultura gótica urbana, celebrado en mayo 2013 en la Universidad Autónoma de MadridLa labor creativa de Alfred Kubin (1877-1959) se extiende a lo largo
de varias décadas que se manifestaron repletas de innovaciones, cambios
y rupturas políticas, sociales y culturales que dificulta cualquier
tentativa de encorsetar o reducir su obra a espacios determinados o a
ismos específicos. Aunque sus primeras obras mantienen una estrecha
relación con el Simbolismo, a lo largo de su existencia vio desarrollarse
movimientos artísticos como el Dadaísmo o el Surrealismo,
que han marcado profundamente el arte del siglo XX. Toda su obra
(ya sean dibujos o textos) es producto de la combinación de una observación
muy detenida con una distorsionada imaginación que hace
visible la tenue línea que separa (o une, según se mire) los aspectos
conscientes e inconscientes. El miedo y la ansiedad que sentía ante
un mundo en el que nunca llegó a sentirse integrado, fueron sus principales
fuentes de inspiración
About Locality and the Relativity Principle Beyond Special Relativity
Locality of interactions is an essential ingredient of Special Relativity.
Recently, a new framework under the name of relative locality
\cite{AmelinoCamelia:2011bm} has been proposed as a way to consider Planckian
modifications of the relativistic dynamics of particles. We note in this paper
that the loss of absolute locality is a general feature of theories beyond
Special Relativity with an implementation of a relativity principle. We give an
explicit construction of such an implementation and compare it both with the
previously mentioned framework of relative locality and the so-called Doubly
Special Relativity theories.Comment: 10 pages, no figure
Radiative decay Z_H-> \gamma A_H in the little Higgs model with T-parity
In the little Higgs model with T-parity (LHTM), the only tree-level
kinematically allowed two-body decay of the Z_H boson is Z_H-> A_H H and thus
one-loop induced two-body decays may have a significant rate. We study the
Z_H-> \gamma A_H decay, which is induced at the one-loop level by a fermion
triangle and is interesting as it depends on the mechanism of anomaly
cancellation of the model. All the relevant two- and three-body decays of the
Z_H gauge boson arising at the tree-level are also calculated. We consider a
small region of the parameter space where the scale of the symmetry breaking f
is still allowed to be as low as 500 GeV by electroweak precision data. We
first analyze the scenario of a Higgs boson with a mass of 120 GeV. We found
that the Z_H->\gamma A_H branching ratio can be of the order of a tree-level
three-body decay and may be at the reach of detection at the LHC for f close to
500 GeV, but it may be difficult to detect for f=1 TeV. There is also an
scenario where the Higgs boson has an intermediate mass such that the Z_H-> A_H
H decay is closed, the Z_H-> \gamma A_H gets considerably enhanced and the
chances of detection get a large boost.Comment: 19 pages, 9 figures, 2 table
Random Hermite differential equations: Mean square power series solutions and statistical properties
This paper deals with the construction of random power series solution of second order linear differential equations of Hermite containing uncertainty through its coefficients and initial conditions. Under appropriate hypotheses on the data, we establish that the constructed random power series solution is mean square convergent. We provide conditions in order to obtain random polynomial solutions and, as a consequence, random Hermite polynomial are introduced. Also, the main statistical functions of the approximate stochastic process solution generated by truncation of the exact power series solution are given. Finally, we apply the proposed technique to several illustrative examples comparing the numerical results with respect to those provided by other available approaches including Monte Carlo simulation. © 2011 Elsevier Inc. All rights reserved.This work has been partially supported by the Spanish M.C.Y.T. and FEDER grants MTM2009-08587, DPI2010-20891-C02-01 as well as the Universitat Politecnica de Valencia grant PAID-06-09 (Ref. 2588).Calbo Sanjuán, G.; Cortés López, JC.; Jódar Sánchez, LA. (2011). Random Hermite differential equations: Mean square power series solutions and statistical properties. Applied Mathematics and Computation. 218(7):3654-3666. https://doi.org/10.1016/j.amc.2011.09.008S36543666218
Conectividad tridimensional durante el verano en el norte del Golfo de California
Connectivity studies in the Gulf of California are an important tool for improving the use and management of the gulf’s natural resources. The goal of this work was to study the three-dimensional connectivity in the northern Gulf of California during two representative months of summer when most local marine species spawn. Passive particles were advected for eight weeks in a three-dimensional current field generated by a three-dimensional baroclinic numerical model. The results indicate that the locations of greatest particle retention were the Upper Gulf and the Seasonal Eddy. The Seasonal Eddy corresponded to the area of largest particle catchment because the continental coastal current carries most particles released in the Midriff Archipelago region; subsequently these particles were entrained in the seasonal cyclonic eddy, causing most of them to remain within it. We conclude that the continental coastal current and the Seasonal Eddy control the connectivity patterns in the northern Gulf of California.Los estudios de conectividad en el Golfo de California (GC) son una herramienta importante para mejorar el uso y la gestión de los recursos naturales del golfo. El objetivo de este trabajo fue estudiar la conectividad tridimensional en el norte del Golfo de California (NGC) durante dos meses representativos de verano, ya que es la temporada con mayor desove de especies marinas. Se advectaron partículas pasivas durante ocho semanas en un campo de corrientes tridimensional generado por un modelo numérico baroclínico tridimensional. Los resultados indicaron que los lugares con mayor retención de las partículas fueron el Alto Golfo (UG) y el Remolino Estacional (SE). A su vez, SE fue el área de máxima captación de partículas debido a que la corriente costera continental transporta la mayoría de las partículas liberadas en las localidades ubicadas en la zona de las Grandes Islas, posteriormente estas partículas son atrapadas por el remolino ciclónico estacional lo que provocó que la mayoría de las partículas liberadas se queden dentro de éste. Por último, concluimos que la corriente costera continental y el remolino estacional controlan los patrones de conectividad en el NGC
Special Geometry of Euclidean Supersymmetry III: the local r-map, instantons and black holes
We define and study projective special para-Kahler manifolds and show that
they appear as target manifolds when reducing five-dimensional vector
multiplets coupled to supergravity with respect to time. The dimensional
reductions with respect to time and space are carried out in a uniform way
using an epsilon-complex notation. We explain the relation of our formalism to
other formalisms of special geometry used in the literature. In the second part
of the paper we investigate instanton solutions and their dimensional lifting
to black holes. We show that the instanton action, which can be defined after
dualising axions into tensor fields, agrees with the ADM mass of the
corresponding black hole. The relation between actions via Wick rotation, Hodge
dualisation and analytic continuation of axions is discussed.Comment: 72 pages, 2 figure
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