War of Shadows MICHAEL F. BROWN; EDUARDO FERNÁNDEZ
09/2023
eBook
War of Shadows is the haunting story of a failed uprising
in the Peruvian Amazon-told largely by people who were there. Late
in 1965, Asháninka Indians, members of one of the Amazon's largest
native ...tribes, joined forces with Marxist revolutionaries who had
opened a guerrilla front in Asháninka territory. They fought, and
were crushed by, the overwhelming military force of the Peruvian
government. Why did the Indians believe this alliance would deliver
them from poverty and the depredations of colonization on their
rainforest home? With rare insight and eloquence, anthropologists
Brown and Fernández write about an Amazonian people whose contacts
with outsiders have repeatedly begun in hope and ended in tragedy.
The players in this dramatic confrontation included militants of
the Movement of the Revolutionary Left (MIR), the U. S. Embassy,
the Peruvian military, a "renegade" American settler, and the
Asháninka Indians themselves. Using press reports and archival
sources as well as oral histories, the authors weave a vivid
tapestry of narratives and counternarratives that challenges the
official history of the guerrilla struggle. Central to the story is
the Asháninkas' persistent hope that a messiah would lead them to
freedom, a belief with roots in eighteenth- and nineteenth-century
jungle rebellions and religious movements.
ABSTRACT
Plant persistence and migration in face of climate change depends on successful reproduction by seed, a central aspect of plant life that drives population dynamics, community assembly and ...species distributions. Plant reproduction by seed is a chain of physiological processes, the rates of which are a function of temperature, and can be modelled using thermal time models. Importantly, while seed reproduction responds to its instantaneous thermal environment, there is also evidence of phenotypic plasticity in response to the thermal history experienced by the plant's recent ancestors, by the reproducing plant since seedling establishment, and by its seeds both before and after their release. This phenotypic plasticity enables a thermal memory of plant reproduction, which allows individuals to acclimatise to their surroundings. This review synthesises current knowledge on the thermal memory of plant reproduction by seed, and highlights its importance for modelling approaches based on physiological thermal time. We performed a comprehensive search in the Web of Science and analysed 533 relevant articles, of which 81 provided material for a meta‐analysis of thermal memory in reproductive functional traits based on the effect size Zr. The articles encompassed the topics of seed development, seed yield (mass and number), seed dormancy (physiological, morphological and physical), germination, and seedling establishment. The results of the meta‐analysis provide evidence for a thermal memory of seed yield, physiological dormancy and germination. Seed mass and physiological dormancy appear to be the central hubs of this memory. We argue for integrating thermal memory into a predictive framework based on physiological time modelling. This will provide a quantitative assessment of plant reproduction, a complex system that integrates past and present thermal inputs to achieve successful reproduction in changing environments. The effects of a warming environment on plant reproduction cannot be reduced to a qualitative interpretation of absolute positives and negatives. Rather, these effects need to be understood in terms of changing rates and thresholds for the physiological process that underlie reproduction by seed.
An analysis of security issues for cloud computing Hashizume, Keiko; Rosado, David G; Fernández-Medina, Eduardo ...
Journal of internet services and applications,
01/2013, Letnik:
4, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Cloud Computing is a flexible, cost-effective, and proven delivery platform for providing business or consumer IT services over the Internet. However, cloud Computing presents an added level of risk ...because essential services are often outsourced to a third party, which makes it harder to maintain data security and privacy, support data and service availability, and demonstrate compliance. Cloud Computing leverages many technologies (SOA, virtualization, Web 2.0); it also inherits their security issues, which we discuss here, identifying the main vulnerabilities in this kind of systems and the most important threats found in the literature related to Cloud Computing and its environment as well as to identify and relate vulnerabilities and threats with possible solutions.
The present study analyzes the soiling losses of a 1 MW photovoltaic system installed in the South of Spain. Both the Levelized Cost of Energy and the Net Present Value are used to compare the ...convenience of different mitigation strategies. It is found that also photovoltaic installations located in moderate regions, where the yearly soiling losses are limited to 3%, can suffer of a severe seasonal soiling, with power drops higher than 20%. In these conditions, an optimized cleaning schedule can be considerably beneficial from an economic perspective. For the given site, an optimal cleaning schedule generates a raise in profits up to 3.6% if one yearly cleaning is performed within a ±31-day window in summer. The convenience of one and multiple cleaning strategies is investigated by considering variable electricity prices and cleaning costs. In addition, the impact of the module efficiency on the cleaning strategy is analyzed. It is found that an optimized cleaning schedule can enhance the benefits of installing high efficiency modules, as it increases the amount of energy recovered through each cleaning and, therefore, the profits.
Display omitted
•Optimized cleaning schedules can be highly beneficial in seasonal soiling conditions.•The investigated site can be profitably cleaned within a 31-day window in summer.•For the given site and conditions, the NPV is more cleaning-prone than the LCOE.•The optimal cleaning number varies with the cleaning cost and the electricity price.•The profits of an optimized cleaning strategy increase with high-efficiency modules.
Bifacial technology is attracting the attention of the photovoltaic community. Although considered premature, research and development activities still need to be carried out to improve bPV ...performance. In addition, the need for a standard test reference will aid bankability and increase confidence in this technology. This article describes the state of the art of bifacial technology, going through the bPV cell and its difference compared to conventional monofacial cells and listing the different sources of limitations, with an identification of different parameters that characterize the performance of the bifacial. Then, the paper reviews the different modeling methods that allow predicting the performance of bPV systems, and ends with the most important applications, whether for dual use of land to produce energy and food (agrivoltaic) or for placing bPV modules on water bodies instead of on the ground (aquavoltaics), or for vertical use as solar fences, acoustic barriers, or building-integrated photovoltaic modules.
The size of the cerebral cortex increases dramatically across amniotes, from reptiles to great apes. This is primarily due to different numbers of neurons and glial cells produced during embryonic ...development. The evolutionary expansion of cortical neurogenesis was linked to changes in neural stem and progenitor cells, which acquired increased capacity of self‐amplification and neuron production. Evolution works via changes in the genome, and recent studies have identified a small number of new genes that emerged in the recent human and primate lineages, promoting cortical progenitor proliferation and increased neurogenesis. However, most of the mammalian genome corresponds to noncoding DNA that contains gene‐regulatory elements, and recent evidence precisely points at changes in expression levels of conserved genes as key in the evolution of cortical neurogenesis. Here, we provide an overview of basic cellular mechanisms involved in cortical neurogenesis across amniotes, and discuss recent progress on genetic mechanisms that may have changed during evolution, including gene expression regulation, leading to the expansion of the cerebral cortex.
•Ultra-high concentrator photovoltaics are promising to low the cost of electricity.•Thermal management is challenging due to the heat produced at ultra-high levels.•The feasibility of flat ...heat-sinks is studied using a Finite Element Analysis (FEA)•Key parameters for passive cooling within 2000–10,000 suns are investigated.•Results show that the temperature stays below 60 °C for cell areas lower than 1 mm2.
Concentrator photovoltaic (CPV) systems replace semiconductor material by cost-efficient optical elements. The potential cost reduction of these systems is closely related to the concentration factor because higher light concentrations imply lower amount of semiconductor material required for the solar cells. Thus, one promising way for improving this technology is moving towards ultra-high (UH) concentration levels (>2000 suns). However, the thermal management at such extreme light fluxes is difficult. Using small-sized solar cells is beneficial for improving the thermal management. Among the possible cooling strategies, the use of flat-plate heat-sinks for passive cooling, if feasible, would be the simplest way to dissipate the heat and would accelerate the development of UHCPV prototypes. However, the feasibility of flat-plate heat-sinks using microscale solar cells for UHCPV applications has not been analysed in detail yet. In this work, a thermal 3D finite-element model is used to investigate the possibilities of flat-plate heat-sinks at concentration ratios not tested to date, i.e. 2000–10,000 suns. Critical parameters such as solar cell area and efficiency, substrate thickness, heat-sink area, and heat-sink material are evaluated and discussed. Results show that solar cells of 1 mm × 1 mm area or below can be thermally handled with conventional Aluminium flat heat-sinks up to 10,000 suns.
High-power laser transmission (HPLT) is attracting a huge interest from both the scientific and industrial community due to its large number of potential applications and future perspectives. This ...technology consists of the use of a monochromatic light source to power supply a remote system by using a photovoltaic converter. HPLT offers a technological paradigm shift with the possibility of transmitting kilowatts to several kilometres without the use of wires. However, HPLT is still under development and the current efficiency, ≈20%, needs to be improved to achieve the actual potential of the technology. This work is focused on the investigation of the most suitable materials to improve the performance of HPLT systems under a wide range of scenarios. For the first time, the monochromatic efficiency of PV converters, considering the attenuation of the atmosphere with the distance, and for various input light intensities and series resistance scenarios, is deeply investigated. The results indicate that high energy gap materials such as ZnS (3.54 eV) or 6H–SiC (3 eV) could lead to record efficiencies and improve current values in more than 30%.
We have investigated the most suitable band-gap materials to transfer kilowatts of laser power to remote systems considering a wide range of scenarios, i.e. energy gap, series resistance, laser power, atmosphere and distance. Our results indicate the high energy gap materials (>2 eV) such as ZnS, SiC, AlP, CdS or InN offer a novel route to improve the efficiency of high-power laser transmission in more than 30%. Display omitted
•The suitable band-gap materials for remote laser high-power are investigated.•Different scenario of energy gap, series resistance and power are selected.•The spectral attenuation of the atmosphere with distance is considered.•High energy gap materials could improve the efficiency in more than 30%.
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